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Sample records for acetate sedimentation concentration

  1. Acetate biodegradation by anaerobic microorganisms at high pH and high calcium concentration

    Acetate biodegradation at a high pH and a high calcium concentration was examined to clarify the effect of bacterial activity on the migration of organic 14C compounds in cementitious repositories. Tamagawa river sediment or Teganuma pond sediment was anaerobically cultured with 5 mM acetate and 10 mM nitrate at pH 9.5-12 at 30 oC. After 20 and 90 days, the acetate concentration of the culture medium was analyzed and found to have decreased below 5 mM at pH ≤ 11. On the other hand, it did not decrease when either sediment was incubated in the absence of nitrate. These results suggest that nitrate-reducing bacteria can biodegrade acetate under more alkaline conditions than the reported pH range in which nitrate-reducing bacteria can exhibit activity. Acetate biodegradation was also examined at a high calcium concentration. Sediments were anaerobically cultured at pH 9.5 with 5 mM acetate and 10 mM nitrate in solution, equilibrated with ordinary Portland cement hydrate, in which the Ca concentration was 14.6 mM. No decrease in acetate concentration after incubation of the sediments was observed, nor was it lower than in the absence of cementitious composition, suggesting that kinetics of acetate biodegradation by anaerobic microorganisms is lowered by a high Ca concentration. - Research highlights: → Acetate biodegradation at a high pH and a high calcium concentration was examined to clarify the effect of bacterial activity on the migration of organic 14C compounds in cementitious repositories. → Nitrate-reducing bacteria can biodegrade acetate at pH ≤ 11. → Kinetics of acetate biodegradation by anaerobic microorganisms might be lowered by a high Ca concentration.

  2. Elevated acetate concentrations in the rhizosphere of Spartina alterniflora and potential influences on sulfate reduction

    Hines, Mark E.; Tugel, Joyce B.; Giblin, A. E.; Banta, G. T.; Hobbie, J. E.

    1992-01-01

    Acetate is important in anaerobic metabolism of non-vegetated sediments but its role in salt marsh soils was not investigated thoroughly. Acetate concentrations, oxidation (C-14) and SO4(2-) reduction (S-35) were measured in S. alterniflora soils in NH and MA. Pore water from cores contained greater than 0.1 mM acetate and in some instances greater than 1.0 mM. Non-destructive samples contained less than 0.01 mM. Acetate was associated with roots and concentrations were highest during vegetative growth and varied with changes in plant physiology. Acetate turnover was very low whether whole core or slurry incubations were used. Radiotracers injected directly into soils yielded rates of SO4(2-) reduction and acetate oxidation not significantly different from core incubation techniques. Regardless of incubation method, acetate oxidation did not account for a significant percentage of SO4(2-) reduction. These results differ markedly from data for non-vegetated coastal sediments where acetate levels are low, oxidation rate constants are high and acetate oxidation rates greatly exceed rates of SO4(2-) reduction. The discrepancy between rates of acetate oxidation and SO4(2-) reduction in marsh soils may be due either to the utilization of substrates other than acetate by SO4(2-) reducers or artifacts associated with measurements of organic utilization by rhizosphere bacteria.

  3. Acetate consumption in anoxic marine sediments: Identification of key players using mixed pure cultures and sediment incubations

    Na, Hyunsoo

    at 10 mM acetate-2 mM (low) sulfate and lower (0.1 and 1 mM) acetate-high sulfate conditions, as revealed by Ion Torrent sequencing of 16S rRNA gene sequences. At 0.1 and 1 mM acetate concentrations, members of the phyla Firmicutes (Fusibacter-related), Fusobacteria, and Bacteroidetes were...... here the flexibility of the microbial communities in response to different geochemical conditions, in high resolution, with biological replicates, using Ion Torrent sequencing. Secondly, we used two different sediment incubation techniques, dialysis tube batch and continuous flow-through bioreactors...

  4. New Technique for Speciation of Uranium in Sediments Following Acetate-Stimulated Bioremediation

    Acetate-stimulated bioremediation is a promising new technique for sequestering toxic uranium contamination from groundwater. The speciation of uranium in sediments after such bioremediation attempts remains unknown as a result of low uranium concentration, and is important to analyzing the stability of sequestered uranium. A new technique was developed for investigating the oxidation state and local molecular structure of uranium from field site sediments using X-Ray Absorption Spectroscopy (XAS), and was implemented at the site of a former uranium mill in Rifle, CO. Glass columns filled with bioactive Rifle sediments were deployed in wells in the contaminated Rifle aquifer and amended with a hexavalent uranium (U(VI)) stock solution to increase uranium concentration while maintaining field conditions. This sediment was harvested and XAS was utilized to analyze the oxidation state and local molecular structure of the uranium in sediment samples. Extended X-Ray Absorption Fine Structure (EXAFS) data was collected and compared to known uranium spectra to determine the local molecular structure of the uranium in the sediment. Fitting was used to determine that the field site sediments did not contain uraninite (UO2), indicating that models based on bioreduction using pure bacterial cultures are not accurate for bioremediation in the field. Stability tests on the monomeric tetravalent uranium (U(IV)) produced by bioremediation are needed in order to assess the efficacy of acetate-stimulation bioremediation.

  5. The Effects of Acetate Buffer Concentration on Lysozyme Solubility

    Forsythe, Elizabeth L.; Pusey, Marc L.

    1996-01-01

    The micro-solubility column technique was employed to systematically investigate the effects of buffer concentration on tetragonal lysozyme solubility. While keeping the NaCl concentrations constant at 2%, 3%, 4%, 5% and 7%, and the pH at 4.0, we have studied the solubility of tetragonal lysozyme over an acetate buffer concentration range of 0.01M to 0.5M as a function of temperature. The lysozyme solubility decreased with increasing acetate concentration from 0.01M to 0.1M. This decrease may simply be due to the net increase in solvent ionic strength. Increasing the acetate concentration beyond 0.1M resulted in an increase in the lysozyme solubility, which reached a peak at - 0.3M acetate concentration. This increase was believed to be due to the increased binding of acetate to the anionic binding sites of lysozyme, preventing their occupation by chloride. In keeping with the previously observed reversal of the Hoffmeister series for effectiveness of anions in crystallizing lysozyme, acetate would be a less effective precipitant than chloride. Further increasing the acetate concentration beyond 0.3M resulted in a subsequent gradual decrease in the lysozyme solubility at all NaCl concentrations.

  6. Vertical distribution of sediment concentration

    Sai-hua HUANG; Zhi-lin SUN; Dan XU; Shan-shan XIA

    2008-01-01

    A simple formula is proposed to predict the vertical distribution of a suspended load concentration in a 2D steady turbulent flow.The proposed formula significantly improves the well-known Rouse formula where sediment concentration has an infinitely large value at the channel bottom and a zero value at the water surface.Based on this formula and the logarithmic ve-locity profile,a theoretical elementary function for the transport rate of a suspended load is developed.This equation improves the Einstein equation in which the unit-width suspended sediment discharge must be solved by numerical integration and a contra-diction between the lower limit of the integral and that of velocity distribution exists.

  7. Three manganese oxide-rich marine sediments harbor similar communities of acetate-oxidizing manganese-reducing bacteria

    Vandieken, Verona; Pester, Michael; Finke, Niko; Hyun, Jung-Ho; Friedrich, Michael W.; Loy, Alexander; Thamdrup, Bo

    2012-01-01

    Dissimilatory manganese reduction dominates anaerobic carbon oxidation in marine sediments with high manganese oxide concentrations, but the microorganisms responsible for this process are largely unknown. In this study, the acetate-utilizing manganese-reducing microbiota in geographically well-separated, manganese oxide-rich sediments from Gullmar Fjord (Sweden), Skagerrak (Norway) and Ulleung Basin (Korea) were analyzed by 16S rRNA-stable isotope probing (SIP). Manganese reduction was the p...

  8. Highly Concentrated Acetic Acid Poisoning: 400 Cases Reviewed

    Konstantin Brusin

    2012-12-01

    Full Text Available Background: Caustic substance ingestion is known for causing a wide array of gastrointestinal and systemic complications. In Russia, ingestion of acetic acid is a major problem which annually affects 11.2 per 100,000 individuals. The objective of this study was to report and analyze main complications and outcomes of patients with 70% concentrated acetic acid poisoning. Methods: This was a retrospective study of patients with acetic acid ingestion who were treated at Sverdlovsk Regional Poisoning Treatment Center during 2006 to 2012. GI mucosal injury of each patient was assessed with endoscopy according to Zargar’s scale. Data analysis was performed to analyze the predictors of stricture formation and mortality. Results: A total of 400 patients with median age of 47 yr were included. GI injury grade I was found in 66 cases (16.5%, IIa in 117 (29.3%, IIb in 120 (30%, IIIa in 27 (16.7% and IIIb in 70 (17.5%. 11% of patients developed strictures and overall mortality rate was 21%. Main complications were hemolysis (55%, renal injury (35%, pneumonia (27% and bleeding during the first 3 days (27%. Predictors of mortality were age 60 to 79 years, grade IIIa and IIIb of GI injury, pneumonia, stages “I”, “F” and “L” of kidney damage according to the RIFLE scale and administration of prednisolone. Predictors of stricture formation were ingestion of over 100 mL of acetic acid and grade IIb and IIIa of GI injury. Conclusion: Highly concentrated acetic acid is still frequently ingested in Russia with a high mortality rate. Patients with higher grades of GI injury, pneumonia, renal injury and higher amount of acid ingested should be more carefully monitored as they are more susceptible to develop fatal consequences.          

  9. Methane production from bicarbonate and acetate in an anoxic marine sediment

    Crill, P. M.; Martens, C. S.

    1986-01-01

    Methane production from C-14 labeled bicarbonate and acetate was measured over the top 28 cm of anoxic Cape Lookout Bight sediments during the summer of 1983. The depth distribution and magnitude of summed radioisotopically determined rates compare well with previous measurements of total methane production and the sediment-water methane flux. Methane production from CO2 reduction and acetate fermentation accounts for greater than 80 percent of the total production rate and sediment-water flux. Methane production from bicarbonate was found to occur in all depth intervals sampled except those in the top 2 cm, whereas significant methane production from acetate only occurred at depths below 10 cm where sulfate was exhausted. Acetate provided 20 to 29 percent of the measured methane production integrated over the top 30 cm of the sediments.

  10. Greenhouse gas production in a pond sediment: Effects of temperature, nitrate, acetate and season

    In this paper we investigate the impact of nitrate (NO3-) concentration and temperature on the production of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). We studied sediment collected during spring, summer and autumn from a constructed pond in South Sweden. Homogenised sediment samples were dark incubated in vitro under N2 atmosphere at 13 oC and 20 oC after addition of five NO3- concentrations, between 0 and 16 mg NO3--N per litre. We found higher net production of N2O and CO2 at the higher temperature. Moreover, increased NO3- concentrations had strong positive impact on the N2O concentration, but no effect on CH4 and CO2 production. The lack of response in CO2 is suggested to be due to the use of alternative oxidants as electron acceptors. Interaction between NO3- and temperature suggests a further increase of N2O net production when both NO3- and temperature are high. Our interpretation of the CH4 data is that at high concentrations of NO3- temperature is of less importance for CH4 production. We also found that at 13 deg. C CH4 production was substrate limited and that the addition of acetate increased CH4 as well as CO2 production. There was a seasonal effect on gas production potential, with more CH4 and N2O produced in spring than in summer. Re-calculation of the gas concentrations into global warming potential (GWP) units (i.e. CO2, CH4, and N2O transferred to CO2 equivalents) shows that GWP increases with temperature. However, under environmental conditions generally occurring in South Swedish ponds, i.e. low temperature and high NO3- concentration during spring and high temperature and low NO3- concentration during summer, NO3- concentration is of minor importance

  11. Formate, acetate, and propionate as substrates for sulfate reduction in sub-arctic sediments of Southwest Greenland

    Glombitza, Clemens; Jaussi, Marion; Røy, Hans;

    2015-01-01

    Volatile fatty acids (VFAs) are key intermediates in the anaerobic mineralization of organic matter in marine sediments. We studied the role of VFAs in the carbon and energy turnover in the sulfate reduction zone of sediments from the sub-arctic Godthåbsfjord (SW Greenland) and the adjacent...... turnover times increased from several hours at the sediment surface to several years at the bottom of the sulfate reduction zone. Thus, diffusion was not limiting the VFA turnover. Despite constant VFA concentrations, the Gibbs energies (ΔGr) of VFA-dependent sulfate reduction decreased downcore, from −28...... energetic limit at ~ −30 kJ (mol acetate)−1. It is not clear what controls VFA concentrations in the porewater but cell physiological constraints such as energetic costs of VFA activation or uptake could be important. We suggest that such constraints control the substrate turnover and result in a minimum...

  12. The carbon isotope biogeochemistry of acetate from a methanogenic marine sediment

    Blair, N. E.; Carter, W. D., Jr.

    1992-01-01

    The delta C-13 value of porewater acetate isolated from the anoxic sediments of Cape Lookout Bight (North Carolina) ranged from -17.6 percent in the sulfate reduction zone to -2.8 percent in the underlying methanogenic zone. The large C-13 enrichment in the sulfate-depleted sediments appears to be associated with the dissimilation of acetate to CH4 and CO2. Fractionation factors for that process were estimated to be 1.032 +/- 0.014 and 1.036 +/- 0.019 for the methyl and carboxyl groups. A subsurface maximum in delta C-13 of the total acetate molecule, as well as the methyl and carboxyl carbons at 10-15 cm depth within the sediment column, indicate that changes in the relative rates of acetate cycling pathways occur in the methanogenic zone. The methyl group of the acetate was depleted in C-13 by 7-14 percent relative to the carboxyl moiety. The intramolecular heterogeneity may be the result of both synthetic and catabolic isotope effects.

  13. Overflow Concentration and Sedimentation in Hoppers

    Hjelmager Jensen, Jacob; Saremi, Sina

    2014-01-01

    result of different timescales in the segregation of the various sediment fractions. The heavier constituents in a mixture will have had time to settle, and overflowing sediments are therefore primarily composed of the finer and lighter constituents, whose concentrations potentially exceed those at the...... inflow. The hopper constitutes a complex system despite its geometrical regularity; the complexities are largely from the settling processes in concentrated polydisperse mixtures. These settling processes can, however, be captured by employing available settling formulas applicable for multifractional...... mixtures, the former analytically. Although assumptions tied to the mathematical model are fulfilled best for hoppers rigged with a multiple-inflow system, the model accurately predicts measured concentrations in the final stage of overflow for single-inflow systems. The model can be used as a...

  14. Acoustic estimation of suspended sediment concentration

    朱维庆; 朱敏; 周忠来; 潘锋; 霍其增; 张向军

    2001-01-01

    In this paper, the acoustic estimation of suspended sediment concentration is discussed and two estimation methods of suspended sediment concentration are presented. The first method is curve fitting method, in which, according to the acoustic backscattering theory we assume that the fit-ting factor K1 (r) between the concentration M(r) obtained by acoustic observation and the concentra-tion M0(r) obtained by sampling water is a high order power function of distance r. Using least-square algorithm, we can determine the coefficients of the high order power function by minimizing the differ-ence between M(r) and M0(r) in the whole water profile. To the absorption coefficient of sound due to the suspension in water we do not give constraint in the first method. The second method is recur-sive fitting method, in which we take M0(r) as the conditions of initialization and decision and give ra-tional constraints to some parameters. The recursive process is stable. We analyzed the two methods with a lot of experimental data. The analytical results show that the estimate error of the first method is less than that of the second method and the latter can not only estimate the concentration of suspended sediment but also give the absorption coefficient of sound. Good results have been obtained with the two methods.

  15. Study on utilizing ultrasonic for measurement of sediment concentration distribution

    JiaChunjuan; TangMaoguan

    1998-01-01

    In the course of sedimentation research, the measurement of sediment concentration and its distribution is very important. At present, most traditional methods are arduous and cannot measure the sediment timely and successively. In order to seek the new measurement method,the paper reports utilizing ultrasonic measurement. When ultrasonic wave spreads along the depth in aqueous suspensions, the scatter intensity of sediment particles changes the depth and sediment concentration. Based on this principle,

  16. 5.3. The kinetics of acetic acid decomposition of calcined borosilicate concentrate

    Present article is devoted to kinetics of acetic acid decomposition of calcined borosilicate concentrate. The experimental data of kinetics of boron oxide extraction from the calcined danburite concentrate at acetic acid decomposition was obtained at 30-90 deg C temperature ranges and 15-60 minutes process duration. It was defined that at temperature increasing the extraction rate of boron oxide from the calcined danburite concentrate significantly increases. The influence of extraction rate of boron oxide on process duration at acetic acid decomposition was studied.

  17. Thermodynamic modeling of neptunium(V)-acetate complexation in concentrated NaCl media

    The complexation of neptunium(V), Np(V), with the acetate anion, Ac-, was measured in sodium chloride media to high concentration using an extraction technique. The data were interpreted using the thermodynamic formalism of Pitzer, which is valid to high electrolyte concentrations. A consistent model for the deprotonation constants of acetic acid in NaCl and NaClO4 media was developed. For the concentrations of acetate expected in a waste repository, only the neutral complex NpO2Ac(aq) was important in describing the interactions between the neptunyl ion and acetate. The thermodynamic stability constant log β0101 for the reaction NpO2+ + Ac- ↔ NpO2Ac was calculated to be 1.46±0.11. This weak complexing behavior between the neptunyl ion and acetate indicates that acetate will not significantly enhance dissolved Np(V) concentrations in ground waters associated with nuclear waste repositories that may contain acetate

  18. Change in the plasmid copy number in acetic acid bacteria in response to growth phase and acetic acid concentration.

    Akasaka, Naoki; Astuti, Wiwik; Ishii, Yuri; Hidese, Ryota; Sakoda, Hisao; Fujiwara, Shinsuke

    2015-06-01

    Plasmids pGE1 (2.5 kb), pGE2 (7.2 kb), and pGE3 (5.5 kb) were isolated from Gluconacetobacter europaeus KGMA0119, and sequence analyses revealed they harbored 3, 8, and 4 genes, respectively. Plasmid copy numbers (PCNs) were determined by real-time quantitative PCR at different stages of bacterial growth. When KGMA0119 was cultured in medium containing 0.4% ethanol and 0.5% acetic acid, PCN of pGE1 increased from 7 copies/genome in the logarithmic phase to a maximum of 12 copies/genome at the beginning of the stationary phase, before decreasing to 4 copies/genome in the late stationary phase. PCNs for pGE2 and pGE3 were maintained at 1-3 copies/genome during all phases of growth. Under a higher concentration of ethanol (3.2%) the PCN for pGE1 was slightly lower in all the growth stages, and those of pGE2 and pGE3 were unchanged. In the presence of 1.0% acetic acid, PCNs were higher for pGE1 (10 copies/genome) and pGE3 (6 copies/genome) during the logarithmic phase. Numbers for pGE2 did not change, indicating that pGE1 and pGE3 increase their PCNs in response to acetic acid. Plasmids pBE2 and pBE3 were constructed by ligating linearized pGE2 and pGE3 into pBR322. Both plasmids were replicable in Escherichia coli, Acetobacter pasteurianus and G. europaeus, highlighting their suitability as vectors for acetic acid bacteria. PMID:25575969

  19. Continuous Ethanol Production with a Membrane Bioreactor at High Acetic Acid Concentrations

    Päivi Ylitervo

    2014-07-01

    Full Text Available The release of inhibitory concentrations of acetic acid from lignocellulosic raw materials during hydrolysis is one of the main concerns for 2nd generation ethanol production. The undissociated form of acetic acid can enter the cell by diffusion through the plasma membrane and trigger several toxic effects, such as uncoupling and lowered intracellular pH. The effect of acetic acid on the ethanol production was investigated in continuous cultivations by adding medium containing 2.5 to 20.0 g·L−1 acetic acid at pH 5.0, at a dilution rate of 0.5 h−1. The cultivations were performed at both high (~25 g·L−1 and very high (100–200 g·L−1 yeast concentration by retaining the yeast cells inside the reactor by a cross-flow membrane in a membrane bioreactor. The yeast was able to steadily produce ethanol from 25 g·L−1 sucrose, at volumetric rates of 5–6 g·L−1·h−1 at acetic acid concentrations up to 15.0 g·L−1. However, the yeast continued to produce ethanol also at a concentration of 20 g·L−1 acetic acid but at a declining rate. The study thereby demonstrates the great potential of the membrane bioreactor for improving the robustness of the ethanol production based on lignocellulosic raw materials.

  20. Growing and laying performance of Japanese quail fed diet supplemented with different concentrations of acetic acid

    Youssef A. Attia

    2013-04-01

    Full Text Available In order to evaluate the effect of acetic acid on growing and laying performance of Japanese Quail (JQ, 180 15-day-old JQ were divided into 4 groups. During the growing (15-42 days of age and laying (43-84 days of age periods, the groups fed the same basal diets supplemented with 0, 1.5, 3 and 6% of acetic acid. Each diet was fed to five replicates of 9 JQ (3 males:6 females during the growing period. During the laying period, 128 birds were housed in 32 cages (4 birds per cage, 1 male and 3 females, 8 replicates per treatment. Birds were housed in wire cages (46L×43W×20H cm in an open room. Acetic acid supplementation at 3% in the diets significantly increased the growth and laying rate and the Haugh unit score. The liver percentage significantly decreased with acetic acid at 6%. Acetic acid at 3% significantly increased hemoglobin concentrations at 6 weeks of age and increased weight of day old chicks hatched. Acetic acid affected the immune system as manifested by an excess of cellular reactions in the intestine as well as lymphoid hyperplasia in the spleen tissue. Degenerative changes in the covering epithelium of the intestinal villi were noted at the 6% concentration of acetic acid. Hepatocyte vacuolation and fatty changes were also observed at this concentration of treatment. In conclusion, 3% acetic acid may be used as a feed supplement for JQ during the growing and laying period to improve the productive performance.

  1. A Study of the Catalysts for the Complete Oxidation of Low Concentration Ethyl Acetate and n-Butyl Acetate

    2001-01-01

    @@ In this work, we have synthesized mixed oxides catalysts supported on γ-Al2O3,using some base metals such as La、 Sr、 Ce、 Ni、 Cu. At the space velocity of 56,000h-1 and at some range of concentration, the complete conversion temperatures( ≥ 98% )of Ethyl acetate and n-butyl acetate are 260℃ and 250℃ respectively. The work has an excellent prospect of industrial application. I will introduce the experiment and results from the following tluee aspects. According to Figure 1, X-ray diffraction pattern of the catalyst have shown not only perovskite structure but also much independent CeO2 phase. During the preparation, the CeO2 was coated over support γ-A12O3 for the better Oxygen storage capacity .By co1mparison, we found that the activity of the catalyst with CeO2 was higher than the activity of the catalyst without CeO2.

  2. THE EFFECTS OF ANIMAL AGE AND ACETIC ACID CONCENTRATION ON PIGSKIN GELATIN CHARACTERISTICS

    Y. Pranoto; A. Pertiwiningrum; Triatmojo, S.; M. Sompie

    2012-01-01

    This research was aimed to study the influence of animal age and concentration of the acetic acid solution on physical and chemical properties of pigskin gelatin. The experiment used Completely Randomized Design (CRD) with two factors. The first factor was animal age consisted of 3 levels (5, 7 and 9 months). The second factor was concentration of acetic acid solution consisted of 3 levels (2, 4 and 6 percents). The result showed that animal age had significant effect (P0.05) on the yields,...

  3. TEMPORAL VARIATION OF SUSPENDED SEDIMENT CONCENTRATION FOR WAVES OVER RIPPLES

    Hyoseob KIM

    2003-01-01

    Variations of suspended sediment concentration over ripples in regular waves were described using an existing numerical model system. Nielsen's (1992) empirical formula for sediment entrainment rate from the bed surface was used with an additional scale factor in the model system. The model system was applied to two typical laboratory experimental conditions selected for description of the variation of suspended sediment concentration.The flow model results are described with regard to wave orbital velocities, vorticity, shear stress, and pressure. The suspended sediment model results show that the suspended sediment concentrations have four or more peak values in a wave period depending on flow and sediment conditions. The model results suggest that the suspended sediment concentrations have four peaks when the ratio of the orbital excursion length amplitude and ripple length is close to 1, and more than four peaks when the ratio of the orbital excursion length amplitude over the ripple length is larger than 1. The computed temporal variations of the suspended sediment concentration for Bosman's (1982) case were compared with measurements, and agreements between them were reasonably good. The computed profiles of the wave-period average suspended sediment concentrations also agreed well with measurements near the beds for the two experimental conditions.

  4. Characterization of a halotolerant acetoclastic methanogen highly enriched from marine sediment and its application in removal of acetate.

    Kita, Akihisa; Suehira, Kazuhito; Miura, Toyokazu; Okamura, Yoshiko; Aki, Tsunehiro; Matsumura, Yukihiko; Tajima, Takahisa; Nishio, Naomichi; Nakashimada, Yutaka

    2016-02-01

    A marine sediment collected from Hiroshima Bay was cultured in artificial seawater, containing 0.51 M NaCl and 60 mM acetate and was found to exhibit active methane production at 37°C. Following four successive serial dilutions of cultures in medium containing 0.51 M NaCl, 60 mM acetate, and antibiotics, the well-acclimated methanogen was found to exhibit growth over a range of NaCl concentration (between 0 M and 2.06 M). The specific growth rates of the highly enriched methanogen, termed strain HA, in the absence of NaCl and in the presence of 1.54 M NaCl were estimated to be 0.037 h(-1) and 0.027 h(-1), respectively. The pH and temperature for optimum growth were determined to be 7.0-8.8 and 37°C, respectively. Although cells that had morphology similar to Methanosaeta sp. became dominant in the culture, methane production was still detected in the medium containing 0.51 M NaCl and other substrates such as methanol, formate, and methylamine, indicating contamination with other methanogens. The phylogenetic tree based on 16S rRNA gene sequences revealed that the strain HA was closely related to Methanosaeta harundinacea 6Ac and 8Ac(T), with sequence similarity of 98% and 97%, respectively. The continuous removal of acetate with upflow anaerobic filter reactor for industrial use of strain HA determined a methane production rate of 70 mM/d under condition of 0.51 M NaCl and successful methane production even under 1.54 M NaCl. PMID:26126941

  5. Memory CD8(+) T Cells Require Increased Concentrations of Acetate Induced by Stress for Optimal Function.

    Balmer, Maria L; Ma, Eric H; Bantug, Glenn R; Grählert, Jasmin; Pfister, Simona; Glatter, Timo; Jauch, Annaïse; Dimeloe, Sarah; Slack, Emma; Dehio, Philippe; Krzyzaniak, Magdalena A; King, Carolyn G; Burgener, Anne-Valérie; Fischer, Marco; Develioglu, Leyla; Belle, Réka; Recher, Mike; Bonilla, Weldy V; Macpherson, Andrew J; Hapfelmeier, Siegfried; Jones, Russell G; Hess, Christoph

    2016-06-21

    How systemic metabolic alterations during acute infections impact immune cell function remains poorly understood. We found that acetate accumulates in the serum within hours of systemic bacterial infections and that these increased acetate concentrations are required for optimal memory CD8(+) T cell function in vitro and in vivo. Mechanistically, upon uptake by memory CD8(+) T cells, stress levels of acetate expanded the cellular acetyl-coenzyme A pool via ATP citrate lyase and promoted acetylation of the enzyme GAPDH. This context-dependent post-translational modification enhanced GAPDH activity, catalyzing glycolysis and thus boosting rapid memory CD8(+) T cell responses. Accordingly, in a murine Listeria monocytogenes model, transfer of acetate-augmented memory CD8(+) T cells exerted superior immune control compared to control cells. Our results demonstrate that increased systemic acetate concentrations are functionally integrated by CD8(+) T cells and translate into increased glycolytic and functional capacity. The immune system thus directly relates systemic metabolism with immune alertness. PMID:27212436

  6. Estimation of suspended sediment concentrations with ADCP in Danube River

    Baranya, Sándor; Jóusa, János

    2013-01-01

    An estimation procedure for suspended sediment concentrations based on the intensity of backscattered sound of acoustic Doppler current profilers (ADCP) is introduced in this paper. Based on detailed moving and fixed boat ADCP measurements with concurrent sediment sampling, we have successfully calibrated the estimation method for a reach of River Danube in Hungary, characterized by significant suspended sediment transport. The effect of measurement uncertainty and various data filtering on s...

  7. Effect of various penetration enhancers concentrations on diclafenac sodium release from cellulose acetate phthalate polymeric film

    El-Nahas Hanan; Fakhry Ghazy; El-Ghamry Hanaa; Sabry; Shereen

    2011-01-01

    An investigation was conducted to evaluate the influence of different penetration enhancers in various concentrations on the release of diclofenac sodium (DFS) as a water-soluble drug from Cellulose acetate phthalate polymeric films containing 50% w/w PEG 600 as plasticizer, to choose the most appropriate enhancer and its optimum concentration to be used to achieve the maximum release and permeation of the drug. The addition of various enhancers, as isopropylmyristate (IPM; 0.2_5...

  8. The effect of oral sodium acetate administration on plasma acetate concentration and acid-base state in horses

    Lindinger Michael I

    2007-12-01

    Full Text Available Abstract Aim Sodium acetate (NaAcetate has received some attention as an alkalinizing agent and possible alternative energy source for the horse, however the effects of oral administration remain largely unknown. The present study used the physicochemical approach to characterize the changes in acid-base status occurring after oral NaAcetate/acetic acid (NAA administration in horses. Methods Jugular venous blood was sampled from 9 exercise-conditioned horses on 2 separate occasions, at rest and for 24 h following a competition exercise test (CET designed to simulate the speed and endurance test of 3-day event. Immediately after the CETs horses were allowed water ad libitum and either: 1 8 L of a hypertonic NaAcetate/acetic acid solution via nasogastric tube followed by a typical hay/grain meal (NAA trial; or 2 a hay/grain meal alone (Control trial. Results Oral NAA resulted in a profound plasma alkalosis marked by decreased plasma [H+] and increased plasma [TCO2] and [HCO3-] compared to Control. The primary contributor to the plasma alkalosis was an increased [SID], as a result of increased plasma [Na+] and decreased plasma [Cl-]. An increased [Atot], due to increased [PP] and a sustained increase in plasma [acetate], contributed a minor acidifying effect. Conclusion It is concluded that oral NaAcetate could be used as both an alkalinizing agent and an alternative energy source in the horse.

  9. Simulation of suspended sediment transport initialized with satellite derived suspended sediment concentrations

    Ratheesh Ramakrishnan; A S Rajawat

    2012-10-01

    Suspended sediment transport in the Gulf of Kachchh is simulated utilizing the suspended sediment concentration (SSC) derived from Oceansat OCM imagery, as the initial condition in MIKE-21 Mud Transport model. Optimization of the model mud parameters, like settling velocity and critical shear stress for erosion are realized with respect to the sediment size distribution and the bottom bed materials observed in the Gulf. Simulated SSCs are compared with alternate OCM derived SSC. The results are observed to be impetus where the model is able to generate the spatial dynamics of the sediment concentrations. Sediment dynamics like deposition, erosion and dispersion are explained with the simulated tidal currents and OCM derived sediment concentrations. Tidal range is observed as the important physical factor controlling the deposition and resuspension of sediments within the Gulf. From the simulation studies; maximum residual current velocities, tidal fronts and high turbulent zones are found to characterise the islands and shoals within the Gulf, which results in high sediment concentrations in those regions. Remarkable variability in the bathymetry of the Gulf, different bed materials and varying tidal conditions induces several circulation patterns and turbulence creating the unique suspended sediment concentration pattern in the Gulf.

  10. Extraction and concentration of phenolic compounds from water and sediment

    Goldberg, M.C.; Weiner, Eugene R.

    1980-01-01

    Continuous liquid-liquid extractors are used to concentrate phenols at the ??g l-1 level from water into dichloromethane; this is followed by Kuderna-Danish evaporative concentration and gas chromatography. The procedure requires 5 h for 18 l of sample water. Overall concentration factors around 1000 are obtained. Overall concentration efficiencies vary from 23.1 to 87.1%. Concentration efficiencies determined by a batch method suitable for sediments range from 18.9 to 73.8%. ?? 1980.

  11. Acoustic estimation of suspended sediment concentration

    ZHU; Weiqing(

    2001-01-01

    [1]Morse, P. H. , Theoretical Acoustics, New York: McGraw-Hill Book Co. , 1968.[2]Skudrjuk, E., Die Grundlagen der Akustik, Wien: Springer-Verlag, 1954.[3]Olshevskii, V. V., Statistical Characteristics of Sea Reverberation, Moscow: Nauka Publisher, 1966.[4]Thorne, P. D., Hardcastl, P. J., Soulsby, R. L., Analysis of acoustic measurements of suspended sediments, J. Geop.Res. , 1993, 98: 899.[5]Guo Jijie, Ren Laifa, Li Yunwu, ln-situ calibration of acoustic measurement of suspended sedienmt, Acta Oceanologica Sini-ca, 1998, (20): 120-125.[6]Zhang Shuying, Li Yunwu, Development and application of an acoustic suspended sediemnt monitoring system, Acta Oceanologica Sinica, 1998, (20): 114-119.[7]Zhang Shuying, Li Yunwu, A theoretical analysis of acoustic suspended sediment obsvervation, Acta Acoustica, 1999, (24):267-274.[8]Zhu Weiqing, Pan Feng, Zhu Min et al. , IOA-1 Multi-function Acoustic Doppler Current Profiler (MADCP), OCEAN'2000,Rhode Island, USA.

  12. Concentration Changes of Medroxyprogesterone Acetate in Serum and Milk in Lactating Woman Who Used Depo Geston

    Su-hua FANG; Dan-li SUN; Hai-ying JIANG; Hong-ying LUO

    2004-01-01

    Objective To determine the concentration changes of medroxyprogesterone acetate (MPA) in serum and milk in the Chinese lactating women who used Depo Geston Methods Ten postpartum and breastfeeding women received an injectable contraceptive of Depo Geston (depo medroxyprogesterone acetate, DMPA, 150 mg/ampoule). Serum and milk samples were collected in the 1st, 2nd, 4th, 6th, 8th 10th and 12th week after contraceptive injection. The concentrations of medroxyprogesterone acetate (MPA) in serum and milk were determined by radioimmunoassay.Results The highest MPA concentration in serum was observed at the 1st week and then the level of serum MPA decreased obviously at the 2nd and 4th week. After the 4th week, the decline of serum MPA level slowed down. The concentration of milk MPA reached the highest level at 1st week. But at the 2nd week the average level of MPA in milk dropped by half The MPA concentration in the milk was changed in the range of 5.2 -8.3 ng/mL in the following 10 weeks. During observation, the average ratios of concentration and area under curve (AUC) in milk/serum were both 0.55. There was a wide variation in MPA concentrations and ratios of milk/serum between subjects.Conclusion MPA concentrations maintained a certaim level at the 12th week after DMPA injection. However, whether mather's intake of DMPA during feeding period has effect on children 's growth, espcially pubertal growth, deserves further studies.

  13. An intercomparison of measurement systems for vapor and particulate phase concentrations of formic and acetic acids

    Keene, William C; Talbot, Robert W.; Andreae, Meinrat O.; Beecher, Kristene; Berresheim, Harold; Castro, Mark; Farmer, J. Carl; Galloway, James N.; Hoffmann, Michael R.; Li, Shao-Meng; Maben, John R.; Munger, J. William; Norton, Richard B.; Pszenny, Alexander A. P.; Puxbaum, Hans

    1989-01-01

    During June 1986, eight systems for measuring vapor phase and four for measuring particulate phase concentrations of formic acid (HCOOH) and acetic acid (CH_3COOH) were intercompared in central Virginia. HCOOH and CH_3COOH vapors were sampled by condensate, mist, Chromosorb 103 GC resin, NaOH-coated annular denuders, NaOH impregnated quartz filters, K_2CO_3 and Na_2CO_3 impregnated cellulose filters, and Nylasorb membranes. Atmospheric aerosol was collected on Teflon and Nuclepore filters usi...

  14. Trace metal concentrations in tropical mangrove sediments, NE Brazil.

    Miola, Brígida; Morais, Jáder Onofre de; Pinheiro, Lidriana de Souza

    2016-01-15

    Sediment cores were taken from the mangroves of the Coreaú River estuary off the northeast coast of Brazil. They were analyzed for grain size, CaCO3, organic matter, and trace metal (Cd, Pb, Zn, Cu, Al, and Fe) contents. Mud texture was the predominant texture. Levels of trace metals in surface sediments indicated strong influence of anthropogenic processes, and diagenetic processes controlled the trace metal enrichment of core sediments of this estuary. The positive relationships between trace metals and Al and Fe indicate that Cu, Zn, Pb, and Cd concentrations are associated mainly with Al and Fe oxy-hydroxides and have natural sources. PMID:26608507

  15. Aromatic hydrocarbon concentrations in sediments of Placentia Bay, Newfoundland

    A study was conducted to examine the potential for contamination of recent sediments with polycyclic aromatic hydrocarbons due to tanker and refinery activity in Placentia Bay, Newfoundland, an area without large local anthropogenic sources of aromatics. Sediment samples were taken from the vicinity of the Come By Chance refinery, Woody Island, Wild Cove, and Port Royal Arm, all in the north end of the bay. The samples were extracted by two methods, dichloromethane extraction of dried sediment for determination of total aromatic hydrocarbon content and hexane extraction of wet sediment for estimation of the bioavailability of hydrocarbons and determination of more volatile compounds. Class analysis of aromatic hydrocarbons was conducted on a NH2 column with detection at 255 nm. Total concentrations of di-tricyclic aromatics were highest at the Woody Island site (0.6 μg/g). The sediments from the Come By Chance site, Wild Cove, and Port Royal Arm sediments contained 0.3, 0.1, and 0.2 μg/g respectively. The hexane extracts from Come By Chance were lowest in di-tricyclic aromatics (0.007 μg/g), with the other sites being equal in concentration (0.01 μg/g). It is evident from the study that aromatic hydrocarbon concentrations in Placentia Bay are elevated in some parts of the bay in the absence of local combustion sources, and that the most likely source is petroleum. 12 refs., 5 figs., 2 tabs

  16. Morphological analysis of Polyethersulfone/polyvinyl Acetate blend membrane synthesized at various polymer concentrations

    Hadi, S. H. A. A.; Mannan, H. A.; Mukhtar, H.; Shaharun, M. S.; Murugesan, T.

    2016-06-01

    This paper reports the effect of varying polymer concentration i.e. solvent/polymer ratio on the morphology and gas transport behaviour of polyethersulfone/polyvinyl acetate blend membrane. The solvent used was dimethylformamide, while the manipulated variable was polymer concentration. The concentrations were varied from 75-90 weight % solvent. A homogeneous surface with dense cross-section structure membranes were successfully developed as deduced from FESEM images. The permeability of CO2 and CH4 gases increased with increasing polymer concentration and an improved CO2/CH4 selectivity was observed. These observation made from the characterization justified the applicability of the blend to be synthesized as membrane for gas separation.

  17. Predictive value of serum medroxyprogesterone acetate concentration for response in advanced or recurrent breast cancer.

    Nishimura, R; Nagao, K; Matsuda, M; Baba, K; Matsuoka, Y; Yamashita, H; Fukuda, M; Higuchi, A; Ikeda, K

    1997-08-01

    Medroxyprogesterone acetate (MPA) is one of the most commonly prescribed drugs for endocrine therapy of metastatic breast cancer. In this study, the serum MPA concentration was measured by high-performance liquid chromatography (HPLC) and evaluated for its usefulness in predicting the response in 79 cases of advanced or recurrent breast cancers. Overall, 29 patients (37%) achieved an objective response. The response rate correlated significantly with the oestrogen receptor (ER) status (P = 0.03), proliferative activity determined by DNA polymerase alpha (P = 0.04), the disease-free interval (DFI) (P = 0.05) and the serum MPA concentration (P < 0.001). Patients with ER-positive tumours, lower proliferative activity, a longer (DFI) or a higher serum MPA concentration responded more frequently. The mean serum MPA concentration in the responders with ER-positive tumours (P = 0.01) or tumours with a lower proliferative activity (P = 0.008) were significantly lower than in cases with ER-negative tumours or tumours with a higher proliferative activity, respectively. Cases with soft tissue metastases showed responses at significantly lower MPA concentrations (P = 0.003) than those with bone or visceral metastases. Furthermore, there was a dramatic decrease in the MPA concentration when a responder with a high concentration became unresponsive to the therapy. Thus, the serum MPA concentration is a determining factor for the response to treatment. PMID:9337682

  18. Sediment acoustic index method for computing continuous suspended-sediment concentrations

    Landers, Mark N.; Straub, Timothy D.; Wood, Molly S.; Domanski, Marian M.

    2016-01-01

    Suspended-sediment characteristics can be computed using acoustic indices derived from acoustic Doppler velocity meter (ADVM) backscatter data. The sediment acoustic index method applied in these types of studies can be used to more accurately and cost-effectively provide time-series estimates of suspended-sediment concentration and load, which is essential for informed solutions to many sediment-related environmental, engineering, and agricultural concerns. Advantages of this approach over other sediment surrogate methods include: (1) better representation of cross-sectional conditions from large measurement volumes, compared to other surrogate instruments that measure data at a single point; (2) high temporal resolution of collected data; (3) data integrity when biofouling is present; and (4) less rating curve hysteresis compared to streamflow as a surrogate. An additional advantage of this technique is the potential expansion of monitoring suspended-sediment concentrations at sites with existing ADVMs used in streamflow velocity monitoring. This report provides much-needed standard techniques for sediment acoustic index methods to help ensure accurate and comparable documented results.

  19. An intercomparison of measurement systems for vapor and particulate phase concentrations of formic and acetic acids

    Keene, William C.; Talbot, Robert W.; Andreae, Meinrat O.; Beecher, Kristene; Berresheim, Harold

    1989-01-01

    During June 1986, eight systems for measuring vapor phase and four for measuring particulate phase concentrations of formic acid (HCOOH) and acetic acid (CH3COOH) were intercompared in central Virginia. HCOOH and CH3COOH vapors were sampled by condensate, mist, Chromosorb 103 GC resin, NaOH-coated annular denuders, NaOH-impregnated quartz filters, K2CO3 and NaCO3-impregnated cellulose filters, and Nylasorb membranes. Atmospheric aerosol was collected on Teflon and Nuclepore filters using both hi-vol and lo-vol systems to measure particulate phase concentrations. Performances of the mist chamber and K2CO3-impregnated filter techniques were evaluated using zero air and ambient air spiked with HCOOH(g) and CH3COOH(g), and formaldehyde from permeation sources. The advantages and drawbacks of these methods are reported and discussed.

  20. Groundwater arsenic concentrations in Vietnam controlled by sediment age

    Postma, Dieke; Larsen, Flemming; Thai, Nguyen Thi; Trang, Pham Thi Kim; Jakobsen, Rasmus; Nhan, Pham Quy; Long, Tran Vu; Viet, Pham Hung; Murray, Andrew Sean

    2012-01-01

    Arsenic contamination of groundwater continues to threaten the health of millions of people in southeast Asia. The oxidation of organic carbon, coupled to the reductive dissolution of arsenic-bearing iron oxides, is thought to control the release of sediment-bound arsenic into groundwater. However......, the cause of the high spatial variability in groundwater arsenic concentrations—which can range from 5 to 500 μg l−1 within distances of a few kilometres—has been uncertain. Here, we combine measurements of sediment age, organic-matter reactivity and water chemistry at four locations along a cross......-section of the arsenic-contaminated Red River floodplain in Vietnam to determine the origin of variations in groundwater arsenic concentrations. The burial age of the aquifer sediments, determined using optical stimulated luminescence, ranged from 460 years near the course of the present-day river to 5...

  1. Comparison of acetate turnover in methanogenic and sulfate- reducing sediments by radiolabeling and stable isotope labeling and by use of specific inhibitors: Evidence for isotopic exchange

    De Graaf, W.; Wellsbury, P.; Parkes, R.J.; Cappenberg, T.E.

    1996-01-01

    Acetate turnover in the methanogenic freshwater anoxic sediments of Lake Vechten, The Netherlands, and in anoxic sediments from the Tamar Estuary, United Kingdom, and the Grosser Jasmunder Bodden, Germany, the latter two dominated by sulfate reduction, was determined, Stable isotopes and radioisotop

  2. Model-based adaptive control of acetate concentration during the production of recombinant proteins with E. coli

    Rocha, I; Ferreira, E. C.

    2003-01-01

    A model-based adaptive linearizing control law was derived for the regulation of the acetate concentration during the fed-batch fermentation of recombinant proteins with high cell density culture of Escherichia coli growing on glucose. An unstructured model for the growth was applied to the major metabolic pathways: oxidative growth on glucose, fermentative growth on glucose, oxidative growth on acetate, and maintenance. A model order reduction method was used to allow the d...

  3. Radioisotope Concentration in Lake Sediments of Maracaibo, Venezuela

    Maracaibo Lake is one of the most important water basing and oil producing regions in Venezuela. Changes in the local environment have been monitored for chemical pollution in the past. For this study we selected a set of sediment samples collected in the shore and analyzed for its radioisotope content. Results show the gamma emitting isotopes distribution. Isotopes concentrations have been determined within the natural K, Th and U families

  4. The variations of suspended sediment concentration in Yangtze River Estuary

    杨云平; 张明进; 李义天; 张为

    2015-01-01

    With the Yangtze River Estuary as an example, this paper analyzes the influence of human activity on the sea water content, the sediment content and the regional transport situation. In both flood seasons and dry seasons, as well as in the whole year, the sediment discharge rate and the suspended sediment concentration (SSC) in the estuary area of the Yangtze River show decreasing trends. In the estuary area, the amount of sediment transported into the South and North Branches and the offshore area is also in a decreasing trend over the years. The SSCs at the sections at the entrances of the South Branch, the South Channel, the North Channel and the South Passage in the Yangtze River Estuary show decreasing trends during 1959-2011. The remote-sensing data reveal that for the same runoff and tidal current combination, the SSC in the surface water is decreased, caused by the dramatic decrease in the sediment discharge and the sediment content from the watershed. Although the SSC in the offshore area does not exhibit an apparent decreasing trend, the SSC in the nearshore area drops by 21.42% during the period of 2003-2011 as compared with that during the period of 1985-2002 before the impounding of the Three Gorges Reservoir. The sediment re-suspension in the estuary slows down the reduction of the SSC. The period of 2003-2011 is dry years for the Yangtze River, when the flow is relatively low. The peak value of the SSC in the coast area shifts inwards for about 1/6°degree of longitude. Due to the deepwater channel improvement project in the North Passage at the Yangtze River Estuary in 1998, the SSC in the waterway area is decreased. With the decrease of the divided flow ratio and the sediment splitting ratio in the entrance and the exit of the North Passage, the SSC in the upper and lower reaches of the North Passage during the period of 2008-2011 is decreased by about 14.25% as compared with that during the period of 2000-2007. Primarily due to the jetty at the

  5. Milk synthetic response of the bovine mammary gland to an increase in the local concentration of amino acids and acetate.

    Purdie, N G; Trout, D R; Poppi, D P; Cant, J P

    2008-01-01

    Rates of secretion of components into milk are a function of precursor concentrations and parameters that describe expression of the milk synthetic enzymes and their sensitivity to precursor concentrations. To establish the enzymatic sensitivities of milk fat yield and mammary acetate utilization to circulating acetate concentration, lactating cows were infused for 10 h with 0 or 40 g of acetate/h in an external iliac artery supplying one udder half. In addition, to investigate the possibility that energy supply influences the milk protein response to an elevated amino acid (AA) concentration, 2 different AA profiles were infused with and without acetate. Six cows, fed a total mixed ration of 21% crude protein ad libitum, were infused with AA at 0 g/h, 30 g/h in the profile of rumen microbes, or 30 g/h in the profile of milk proteins, in a 3 x 2 factorial arrangement with the 2 acetate treatments of 0 and 40 g/h, all in a 6 x 6 Latin square. Amino acid infusion caused a 60% increase, on average, in plasma concentration of AA entering the infused udder half. From the microbial AA profile, 49% of infused AA were taken up by the udder half, 42% of which occurred during the first pass. From the milk AA profile, 44% of infused AA were taken up by the udder half, 50% of which occurred during the first pass. There was an 8% increase in yield of milk protein with AA infusion, representing 7% capture, but no effect of the infused profile. Acetate infusion caused a decrease in the yields of milk protein and lactose when AA were infused, but not when AA were absent. Milk fat yields were not affected, although acetate concentrations in plasma entering the infused udder half increased by 123% and mammary uptakes increased by 128%. Mammary uptakes of long-chain fatty acids and beta-hydroxybutyrate were not affected by acetate infusion, whereas glucose uptakes tended to increase. It was suggested that excess acetate may have been sequestered in adipose tissue in the udder. Yields

  6. Biohydrogen production from household solid waste (HSW) at extreme-thermophilic temperature (70 degrees C) - Influence of pH and acetate concentration

    Liu, Dawei; Min, Booki; Angelidaki, Irini

    2008-01-01

    Hydrogen production from household solid waste (HSW) was performed via dark fermentation by using an extreme-thermophilic mixed culture, and the effect of pH and acetate on the biohydrogen production was investigated. The highest hydrogen production yield was 257 +/- 25 mL/gVS(added) at the optimum...... pH of 7.0. Acetate was proved to be inhibiting the dark fermentation process at neutral pH, which indicates that the inhibition was caused by total acetate concentration not by undissociated acetate. Initial inhibition was detected at acetate concentration of 50 mM, while the hydrogen fermentation...... negative effect on the hydrogen yield, acetate was resulting in the longer lag phase during batch fermentations. The lag phase was more than 100 h at acetate concentration of more than 150 mM, while it was only 3-4 h at 5-25 mM acetate....

  7. Metal and radionuclide concentrations in L-lake sediments

    The cycling of iron, manganese and other metals can have important ecological implications in acidic southeastern lakes and reservoirs. When water in a lake's hypolimnion is anoxic, as typically occurs in summer, the solubility of certain elements, such as iron and manganese, increases. During such anoxic conditions, remobilization of elements from lake sediments into the hypolimnion may also occur. Concentrations of these elements can reach levels that are toxic to organisms. Perhaps more importantly, when turnover of the water column occurs in autumn, oxygenation of the anoxic hypolimnion may cause precipitation of metal oxides, forming colloids that can be harmful to fish and other organisms, e.g., by physically obstructing gills. all of these processes can have bearing on the development of a balanced biological community in L-Lake. The inventory of metal and radionuclide concentrations in L-Lake basin sediments will be used to assess potential remobilization of these elements from the lake sediments into the overlying water column. These data will be used in conjunction with laboratory microcosm studies and lake measurements to determine the potential for element remobilization under existing lake conditions. 1 figure, 2 tables

  8. Plasma concentrations of medroxyprogesterone acetate and megesterol acetate during long-term follow-up in patients treated for metastatic breast cancer.

    Miller, A A; Becher, R; Schmidt, C G

    1988-01-01

    A total of 32 patients with metastatic breast cancer responding with at least disease stabilization to treatment with two commercially available preparations of medroxyprogesterone acetate (MPA) or one preparation of megestrol acetate (MA) were followed for their plasma concentrations. The MPA and MA were measured by HPLC. MPA from Upjohn and Farmitalia was given to 12 patients (median age, 61 years; median follow-up, 20 weeks) and 8 patients (54 years, 16 weeks), respectively, on a schedule of 1000 mg daily i.m. for 10 days followed by 200 mg t.i.d.p.o. for the remainder of the treatment course. The peak concentrations (means, 163 vs 97 ng/ml), the time to peak levels (medians, 3 vs 10 weeks), and the areas under the concentration curves from time 0 to 24 weeks (means, 2400 vs 1868 ng/ml X weeks) were significantly different in the respective treatment groups (t-test; significance level, 0.05). MA from Bristol-Myers was administered orally in one daily dose of 160 mg throughout the treatment course in 12 patients (median age, 51 years; median follow-up, 20 weeks). A mean MA peak concentration of 218 ng/ml was reached after a median of 7 days. Plateau plasma levels were higher for MA than MPA. PMID:2965155

  9. Sodium chloride concentration determines exoelectrogens in anode biofilms occurring from mangrove-grown brackish sediment.

    Miyahara, Morio; Kouzuma, Atsushi; Watanabe, Kazuya

    2016-10-01

    Single-chamber microbial fuel cells (MFCs) were inoculated with mangrove-grown brackish sediment (MBS) and continuously supplied with an acetate medium containing different concentrations of NaCl (0-1.8M). Different from MFCs inoculated with paddy-field soil (high power outputs were observed between 0.05 and 0.1M), power outputs from MBS-MFCs were high at NaCl concentrations from 0 to 0.6M. Amplicon-sequence analyses of anode biofilms suggest that different exoelectrogens occurred from MBS depending on NaCl concentrations; Geobacter occurred abundantly below 0.1M, whereas Desulfuromonas was abundant from 0.3M to 0.6M. These results suggest that NaCl concentration is the major determinant of exoelectrogens that occur in anode biofilms from MBS. It is also suggested that MBS is a potent source of microbes for MFCs to be operated in a wide range of NaCl concentrations. PMID:27420153

  10. Zymomonas with improved ethanol production in medium containing concentrated sugars and acetate

    Caimi, Perry G.; Chou, Yat-Chen; Franden, Mary Ann; Knoke, Kyle; Tao, Luan; Viitanen, Paul V.; Zhang, Min; Zhang, Yuying

    2010-09-28

    Through screening of a Zymomonas mutant library the himA gene was found to be involved in the inhibitory effect of acetate on Zymomonas performance. Xylose-utilizing Zymomonas further engineered to reduce activity of the himA gene were found to have increased ethanol production in comparison to a parental strain, when cultured in medium comprising xylose and acetate.

  11. Alternative procedure to determine radionuclide concentrations for marine sediment dating

    The development of an alternative method to prepare and to measure marine sediment samples for dating purpose using high resolution gamma spectrometry is given. To calculate the 137 Cs and the supported and unsupported 210 Pb concentrations, cylindrical tablets subjected to different pressures were analyzed. Mass attenuation coefficients (MAC) were determined by our variant of the transmission method, the Bragg law (using MACs provided by the web program XCOM) and the method of average composition of the analyzed sediment samples. The differences between obtained results are smaller than the experimental error (10%). The influence of pressure and sediment mass on the MAC, mechanical stability of the sample, and self-absorption corrections for different gamma energies is studied. Optimal dimensions of the tablets were determined from considerations on the infinite thickness, minimum detectable activity, precision of results, radiation self-absorption and geometric efficiency. Based on the differential peak absorption analysis, through a relative efficiency curve, a new method to evaluate the existence of radioactive equilibrium between 226 Ra, 222 Rn and its progeny is given. Experimental error of the proposed methodology is evaluated, as well as accuracy, precision and detection limit. With the use of developed methodology, the 210 Pb, 226 Ra and 137 Cs activities in recent sediment samples from near shore of the Orinoco River Delta were determined. The results were comparable with the obtained by two of the most used methods, while precision is improved and radiation self-absorption in sample container is avoided since sample encapsulation is not required. (Full Text)

  12. Microplastic concentrations in beach sediments along the German Baltic coast.

    Stolte, Andrea; Forster, Stefan; Gerdts, Gunnar; Schubert, Hendrik

    2015-10-15

    The contamination with microplastic particles and fibres was evaluated on beaches along the German Baltic coast. Sediments were sampled near the Warnow and Oder/Peene estuaries, on Rügen island and along the Rostock coast to derive possible entry pathways. Seasonal variations were monitored along the Rostock coast from March to July 2014. After density separation in saline solution, floating particles were found to be dominated by sand grains. Water surface tension is shown to be sufficient to explain floatation of grains with sizes less than 1.5mm. Selecting intensely coloured particles and fibres, we find lower limits of the microplastic concentrations of 0-7 particles/kg and 2-11 fibres/kg dry sediment. The largest microplastic contaminations are measured at the Peene outlet into the Baltic Sea and in the North Sea Jade Bay. City discharges, industrial production sites, fishing activity and tourism are the most likely sources for the highest microplastic concentrations. PMID:26198261

  13. Concentration of 60Co by marine organisms through sediments

    Uptake of 60Co absorbed on sea sands by benthic marine organisms was observed in laboratory experiments, since the radioactive cobalt released from nuclear power plants or other establishments into coastal seawater trends to be absorbed on sea sediments and also various kinds of marine organisms live in bottom sediments. Few kinds of flatfishes (Limanda spp.) and shrimp (Trachypenaeus curvirostris) were reared in aquariums contained seawater and sea sands which were highly contaminated with 60Co previously, and whole body retention and distribution of radioactivity were measured on the organisms taken up from the aquariums occasionally by a scintillation counter. Uptake of 60Co from ingested sea sands was also observed on the flatfishes administrating the contaminated sands orally. Concentration of 60Co by the flatfishes reared in the sands was not significant while the shrimp showed high retention of the radioactivity. The food habit of shrimp which usually feeds on organic detritus with other small benthic organisms is different from that of flatfishes, one of the carnivorous, and considered to bring the difference on the pathway of radionuclides concentration. Assimilation of 60Co via the digestive tract of flatfishes through the sands was estimated as about 10 per cent of the administrated radioactivity. (auth.)

  14. Effect of various penetration enhancers concentrations on diclafenac sodium release from cellulose acetate phthalate polymeric film

    El-Nahas Hanan

    2011-01-01

    Full Text Available An investigation was conducted to evaluate the influence of different penetration enhancers in various concentrations on the release of diclofenac sodium (DFS as a water-soluble drug from Cellulose acetate phthalate polymeric films containing 50% w/w PEG 600 as plasticizer, to choose the most appropriate enhancer and its optimum concentration to be used to achieve the maximum release and permeation of the drug. The addition of various enhancers, as isopropylmyristate (IPM; 0.2_5% w/w, oleic acid (OA; 0.2_5% w/w and linoleic acid (LOA; 0.2_5% w/w, Tween 80 (T80;1_10% w/w and transcutol, (TC; 1_10% w/w enhanced the DFS release from the polymeric films. The enhancement ratio of the penetration enhancers used in the formulation of DFS were found to increase in the order of IPM>LOA>OA>T80>TC. (56.2, 54.1, 50, 48.7 and 48%, respectively. In vitro permeation studies were performed using rabbit abdominal skin as the permeating membrane. The results indicated that maximum permeation was obtained at 24hrs (0.5% IPM, 0.2% LOA, 1% OA, 0.5% T80 and 10% TC, increased skin permeation of DFS by 4.46, 4.06, 3.37, 1.65 and 1.49 time, respectively. IPM was found to be the most efficient enhancer. The results obtained from ANOVA test indicate that the difference in drug permeation rates is highly significant compared to the control formulation (P<0.05. The mechanism of drug release from the polymeric films obey Higuchi′s model.

  15. Exhaled breath concentrations of acetic acid vapour in gastro-esophageal reflux disease

    Dryahina, Kseniya; Pospíšilová, Veronika; Sovová, Kristýna; Shestivska, Violetta; Kubišta, Jiří; Spesyvyi, Anatolii; Pehal, F.; Turzíková, J.; Votruba, J.; Španěl, Patrik

    2014-01-01

    Roč. 8, č. 3 (2014), 037109. ISSN 1752-7155 Institutional support: RVO:61388955 Keywords : SIFT-MS * gastro-esophageal reflux * acetic acid Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.631, year: 2014

  16. Phase diagram of uranyl acetate-water-tri-n-butyl phosphate system in the region of high salt concentrations

    The results of investigations into mutual solubility in the system of uranyl acetate-water-tributyl phosphate (the range of high salt concentrations) at 25 deg C are presented. The phase diagram of the system in the solubility range is shown to differ sharply from the most of diagrams of the known systems of salt-water-tributyl phosphate. An attempt is made to associate the unusual character of the solubility isotherm with change of the role of water in extraction and dissolution processes at transition from halogenoacetates to uranyl acetate. Based on IR spectroscopic data the conclusion is made on uranyl acetate solvation in the organic phase only with one molecule of tributyl phosphate, but not two molecules, as it was considered earlier

  17. SEDIMENT YIELD MODELING FOR SINGLE STORM EVENTS BASED ON HEAVY-DISCHARGE STAGE CHARACTERIZED BY STABLE SEDIMENT CONCENTRATION

    2007-01-01

    The relation between runoff volume and sediment yield for individual events in a given watershed receives little attention compared to the relation between water discharge and sediment yield, though it may underlie the event-based sediment-yield model for large-size watershed. The data observed at 12 experimental subwatersheds in the Dalihe river watershed in hilly areas of Loess Plateau, North China,was selected to develop and validate the relation. The peak flow is often considered as an important factor affecting event sediment yield. However, in the study areas, sediment concentration remains relatively constant when water discharge exceeds a certain critical value, implying that the heavier flow is not accompanied with the higher sediment transport capacity. Hence, only the runoff volume factor was considered in the sediment-yield model. As both the total sediment and runoff discharge were largely produced during the heavy-discharge stage, and the sediment concentration was negligibly variable during this stage, a proportional function can be used to model the relation between event runoff volume and sediment yield for a given subwatershed. The applicability of this model at larger spatial scales was also discussed, and it was found that for the Yaoxinzhuang station at the Puhe River basin, which controls a drainage area of 2264km2, a directly proportional relation between event runoff volume and sediment yield may also exist.

  18. PREDICTION OF THE GRAIN SIZE OF SUSPENDED SEDIMENT: IMPLICATIONS FOR CALCULATING SUSPENDED SEDIMENT CONCENTRATIONS USING SINGLE FREQUENCY ACOUSTIC BACKSCATTER

    R. A. KUHNLE; D. G. WREN; J. P. CHAMBERS

    2007-01-01

    Collection of samples of suspended sediment transported by streams and rivers is difficult and expensive. Emerging technologies, such as acoustic backscatter, have promise to decrease costs and allow more thorough sampling of transported sediment in streams and rivers. Acoustic backscatter information may be used to calculate the concentration of suspended sand-sized sediment given the vertical distribution of sediment size. Therefore, procedures to accurately compute suspended sediment size distributions from easily obtained river data are badly needed. In this study, techniques to predict the size of suspended sand are examined and their application to measuring concentrations using acoustic backscatter data are explored. Three methods to predict the size of sediment in suspension using bed sediment, flow criteria, and a modified form of the Rouse equation yielded mean suspended sediment sizes that differed from means of measured data by 7 to 50 percent. When one sample near the bed was used as a reference, mean error was reduced to about 5 percent. These errors in size determination translate into errors of 7 to 156 percent in the prediction of sediment concentration using backscatter data from 1 MHz single frequency acoustics.

  19. Impact of acetic acid concentration of fermented liquid feed on growth performance of piglets

    Canibe, Nuria; Pedersen, Anni Øyan; Jensen, Bent Borg

    2010-01-01

    acid in FLF on feed intake of weaners. Three experimental FLF diets were prepared to contain varying levels of acetic acid (30, 60, and 120 mM). Twenty piglets per treatment, weaned at 4 weeks of age and housed individually, were fed the experimental diets during six weeks starting at weaning. Feed...

  20. Satellite estimates of wide-range suspended sediment concentrations in Changjiang (Yangtze) estuary using MERIS data

    Shen, F; W. Verhoef; Zhou, Y.; Salama, M.S.; X. Liu

    2010-01-01

    The Changjiang (Yangtze) estuarine and coastal waters are characterized by suspended sediments over a wide range of concentrations from 20 to 2,500 mg l-1. Suspended sediment plays important roles in the estuarine and coastal system and environment. Previous algorithms for satellite estimates of suspended sediment concentration (SSC) showed a great limitation in that only low to moderate concentrations (up to 50 mg l-1) could be reliably estimated. In this study, we developed a semi-empirical...

  1. Measuring and modeling suspended sediment concentration profiles in the surf zone

    2012-01-01

    Time-averaged suspended sediment concentration profiles across the surf zone were measured in a large-scale three-dimensional movable bed laboratory facility (LSTF:Large-scale Sediment Transport Facility). Sediment suspension under two different types of breaking waves, spilling and plunging breakers, was investigated. The magnitudes and shapes of the concentration profiles varied substantially at different locations across the surf zone, reflecting the different intensities of breaking-induced turbulence. Sediment sus- pension at the energetic plunging breaker-line was much more active, resulting in nearly homogeneous concentration profiles throughout most of the water column, as compared to the reminder of the surf zone and at the spilling breaker-line. Four suspended sediment concentration models were examined based on the LSTF data, including the mixing turbulence length approach, segment eddy viscosity model, breaking-induced wave-energy dissipation approach, and a combined breaking and turbulence length model developed by this study. Neglecting the breaking-induced turbulence and subsequent sediment mixing, suspended sediment concentration models failed to predict the across-shore variations of the sediment suspension, especially at the plunging breaker-line. Wave-energy dissipation rate provided an accurate method for estimating the intensity of turbulence generated by wave breaking. By incorporating the breaking-induced turbulence, the combined breaking and turbulence length model reproduced the across-shore variation of sediment suspension in the surf zone. The combined model reproduced the measured time-averaged suspended sediment concentration profiles reasonably well across the surf zone.

  2. Sediment concentration rating curves for a monsoonal climate: upper Blue Nile

    Moges, Mamaru A.; Zemale, Fasikaw A.; Alemu, Muluken L.; Ayele, Getaneh K.; Dagnew, Dessalegn C.; Tilahun, Seifu A.; Steenhuis, Tammo S.

    2016-07-01

    Information on sediment concentration in rivers is important for design of reservoirs and for environmental applications. Because of the scarcity of continuous sediment data, methods have been developed to predict sediment loads based on few discontinuous measurements. Traditionally, loads are being predicted using rating curves that relate sediment load to discharge. The relationship assumes inherently a unique relationship between concentration and discharge and therefore although performing satisfactorily in predicting loads, it may be less suitable for predicting concentration. This is especially true in the Blue Nile Basin of Ethiopia where concentrations decrease for a given discharge with the progression of the rainy monsoon phase. The objective of this paper is to improve the sediment concentration predictions throughout the monsoon period for the Ethiopian highlands with a modified rating type equation. To capture the observed sediment concentration pattern, we assume that the sediment concentration was at the transport limit early in the rainy season and then decreases linearly with effective rainfall towards source-limited concentration. The modified concentration rating curve was calibrated for the four main rivers in the Lake Tana basin where sediment concentrations affect fish production and tourism. Then the scalability of the rating type equation was checked in three 100 ha watersheds for which historic data were available. The results show that for predicting sediment concentrations, the (modified) concentration rating curve was more accurate than the (standard) load rating curve as expected. In addition loads were predicted more accurately for three of the four rivers. We expect that after more extensive testing over a wider geographical area, the proposed concentration rating curve will offer improved predictions of sediment concentrations in monsoonal climates.

  3. Sediment concentration rating curves for a monsoonal climate: upper Blue Nile Basin

    Moges, M. A.; Zemale, F. A.; Alemu, M. L.; Ayele, G. K.; Dagnew, D. C.; Tilahun, S. A.; Steenhuis, T. S.

    2015-12-01

    Information on sediment content in rivers is important for design of reservoirs and for environmental applications. Because of scarcity of continuous sediment data, methods have been developed to predict sediment loads based on few discontinuous measurements. Traditionally, loads are being predicted using rating curves that relate sediment load to discharge. The relationship assumes inherently a unique relationship between concentration and discharge and therefore although performing satisfactorily in predicting loads, it may be less suitable for predicting concentration. This is especially true in the Blue Nile basin of Ethiopia where concentrations decrease for a given discharge with the progression of the rainy monsoon phase. The objective of this paper is to improve the sediment concentration predictions throughout the monsoon period for the Ethiopian highlands with a modified rating type equation. To capture the observed sediment concentration pattern, we assume that the sediment concentration was at the transport limit early in the rainy season and then decrease linearly with effective rainfall towards source limited concentration. The modified concentration rating curve was calibrated for the four main rivers in the Lake Tana basin where sediment concentrations affect fish production and tourism. Then the scalability of the rating type equation was checked in three 100-ha watersheds for which historic data was available. The results show, that for predicting sediment concentrations, the (modified) concentration rating curve was more accurate than the (standard) load rating curve as expected. In addition loads were predicted more accurately for three of the four rivers. We expect that after more extensive testing over a wider geographical area, the proposed concentration rating curve will offer improved predictions of sediment concentrations in monsoonal climates.

  4. Impact of rainfall intensity and cutslope material on sediment concentration from forest roads in northern Iran

    Rahbari Sisakht S; Majnounian B; Mohseni Saravi M; Abdi E; Surfleet C

    2014-01-01

    Forest roads are important for adequate management of natural resources, but they are also a dominant contributor of sediment to forest streams and water pollution. This study measured road sediment concentration from forest roads to determine the impact of rainfall intensity and cutslope types on sediment concentration in the Patom district of northern Iran. Two 110 m road segments with variable soil and rock fragment cover exposed at the cutslopes were studied. Seven rainfall and correspond...

  5. Suspended sediment concentration profiles from synoptic satellite observations

    Ramakrishnan, R.; Rajawat, A.S.; Chauhan, O.S.

    , vertical SSC profiles are defined by power law being based on the frictional velocities and sediment settling velocities. For each water pixel in OCM, the vertical variations in SSC are determined from the SSC profiles calculated from power law using...

  6. Saturation Concentrations of Suspended Fine Sediment: Computations with the Prandtl Mixing-Length Model

    Kranenburg, C.

    1998-01-01

    Adopting a 1DV numerical model including the standard k-eps turbulence model, Winterwerp et al. (1999) calculated a saturation concentration for an initially uniform distribution of fine sediment concentration in steady flow. At concentrations exceeding the saturation concentration the concentration

  7. The Use of Measured Suspended Sediment Concentrations at Alcatraz to Infer Net Suspended Sediment Transport at the Golden Gate

    Erikson, L. H.; Wright, S. A.; Elias, E.; Hanes, D. M.; Schoellhamer, D. H.

    2012-12-01

    Numerical model simulations combined with physical measurements were used to estimate the net volumetric water and suspended sediment flux at teh Golden Gate between San Francisco Bay and the coastal ocean. Measurements were obtained using vessel-mounted acoustic Doppler current profilers and semi-empirical calibrations between backscatter intensity and in situ suspended-sediment concentrations throughout the water column. Transects across the inlet were repeated continuously for >12 h during both spring and neap tides to provide near-synoptic measurements over full tidal cycles. A numerical model was validated against volumetric water flux and calibrated against sediment flux measurements which were then used to estimate net sediment exchange. The product of current vectors computed with a numerical model and synoptic measurements of suspended- sediment concentrations at the nearby continuous monitoring site on Alcatraz Island showed reasonable correlation with tide-averaged sediment flux through the Gate; this provided a basis for the development of an analytical relationship to estimate suspended sediment flux through the Golden Gate using continuous measurements at Alcatraz as a proxy.

  8. Concentration-dependent sedimentation properties of ferritin: implications for estimation of iron contents of serum ferritins

    Serum ferritins from various sources sedimented at lower densities than tissue ferritins in sucrose gradient centrifugation systems. The sedimentation patterns of ferritins, however, were shown to be dependent on the concentration of the protein; as the concentration decreased the protein appeared to sediment at lower densities. Thus, at the low concentration levels usually used for analysis of serum ferritin, tissue ferritins also sedimented in the same lower density regions. Iron labeling experiments indicated that the sedimentation changes upon dilution were not due to release of iron or was there any indication that the protein dissociated into subunits. The anomalous sedimentation behavior of serum ferritin should therefore not be interpreted in terms of its iron content. The disclosure that serum ferritins may have full complements of iron is counter to the prevalent view that serum ferritins are low iron forms and has potential implications with regard to the sources and possible function of this protein in the circulation

  9. Trace metal concentrations in lake and overbank sediments in southern Norway

    Rognerud, S. [Norwegian Institute for Water Research, Ottestad (Norway); Hongve, D. [Statens Inst. for Folkehelse, Oslo (Norway); Fjeld, E. [Norsk Inst. for Vannforskning, Oslo (Norway); Ottesen, R.T. [Norges Geologiske Undersoekelse, Trondheim (Norway)

    2000-05-01

    As, Be, Cd, Co, Cr, Cu, Hg, Ni, Pb, V, Se and Zn concentrations were determined and compared in lake and overbank sediments from 33 catchments without local pollution sources in southern Norway. There were no significant differences in concentrations of Be, Co, Cr, Cu, Ni, and V in overbank and pre-industrial lake sediments. In areas with shallow overburden, and significant influence from long-range atmospheric pollution, concentrations of As, Cd, Hg, Pb, Se, and Zn in overbank sediments were probably modified by vertical percolating water. In such areas, we suggest using lake sediments as a better sampling medium for mapping pre-industrial concentrations. Pre-industrial lake sediments yield natural concentrations of Hg and Se, which consist of both geogenic and natural atmospheric deposition. Important covariables like organic carbon content, Fe oxides, and fine mineral fraction were generally higher in pre-industrial lake sediments as compared to overbank sediments. By adjusting for such differences overbank sediments could be used as an alternative in mapping background concentrations of trace metals in regions with few lakes. (orig.)

  10. MODELLING OF SEDIMENTS CONCENTRATION DISTRIBUTION IN DREDGED CANALS OF THE NIGER DELTA ESTUARINE REGION, NIGERIA

    Charles Chizom Dike

    2013-01-01

    Full Text Available Previous sediments concentration distributi on models used in the study of sediment characteristics of the dredged canals in the Niger-Delta estuarine region, Nigeria; did not take into consideration the lateral in flow due to tidal effects, which affects tremendously, the sediment intake into the estuarine waters. In the current research, existing models are modified by incorpora ting the missing lateral inflow parameters, which are peculiar to the Niger Delta environment, to obtain more accurate model results. Details are given herein, of the deve lopment and application of a 3-dimensional numerical model (EKU 2.8 Models to predict sediment concentration distribution (total suspended sediment & bed sediment load s in the Niger Delta estuarine canals, with Ekulama well 19 access canal as a case study. The approach in this paper involved coupling a sediment transport equation (w ith the inclusion of lateral inflow parameters, with an estuarine hydro-dy namics equation to generate a generic 3- dimensional sediment concentration distribu tion model, using deterministic approach. Predicted results using this model compar ed favorably with measured field results. Average sediment concentration of 29mg/l was obtained compared with 31mg/l measured in the field for bed sediment loads. Finally, the predicted sediment concentration distribution (TSS, when comp ared with field results, gave average correlation coefficient of 0.9.; hence, the present model will assist in generating adequate information /data on sediment ch aracteristics and transport mechanism, required for effective design of canals to redu ce rate of siltation. The application of the above knowledge/parameters generated from this model to effectively design canals to reduce siltation will be treated in subsequent articles.

  11. Spatial and temporal variability of suspended-sediment concentrations in a shallow estuarine environment

    Catherine A. Ruhl

    2004-05-01

    Full Text Available Shallow subembayments respond differently than deep channels to physical forces acting in estuaries. The U.S. Geological Survey measured suspended-sediment concentrations at five locations in Honker Bay, a shallow subembayment of San Francisco Bay, and the adjacent channel to investigate the spatial and temporal differences between deep and shallow estuarine environments. During the first freshwater pulse of the wet season, the channel tended to transport suspended sediments through the system, whereas the shallow area acted as off-channel storage where deposition would likely occur. Following the freshwater pulse, suspended-sediment concentrations were greater in Honker Bay than in the adjacent deep channel, due to the larger supply of erodible sediment on the bed. However, the tidal variability of suspended-sediment concentrations in both Honker Bay and in the adjacent channel was greater after the freshwater pulse than before. During wind events, suspended-sediment concentrations in the channel were not affected; however, wind played a crucial role in the resuspension of sediments in the shallows. Despite wind-wave sediment resuspension in Honker Bay, tidally averaged suspended-sediment flux was controlled by the flood-dominated currents.

  12. Nutrient Concentration Distribution in Sediment and Overlying Water at Bukit Merah Reservoir, Perak

    Talib S. H. A.

    2016-01-01

    Full Text Available Bukit Merah Reservoir (BMR is the oldest reservoir in Malaysia constructed to supply irrigation water to the Kerian Irrigation Scheme. Depletion of storage capacity due to sedimentation process is the most concerning issue of the reservoir recently. Sediment analysis is also very important when monitoring the substances that appear in the reservoir water. Environmental toxins, like heavy metals and hydrophobic organic components, as well as nutrients such as nitrogen and phosphorus are readily bond to the particulate matter. Factors in the reservoir that affect the particulate matter will aid the distribution of contaminants in the sediments. The contaminants in the sediments could have higher concentrations compared to those found in the overlying water. This means that the sediment plays an important role in the cycling of nutrients and distribution of contaminants in the ecosystem. The objectives of this research are to determine the relationship of nutrient and heavy metal content for sediment and overlying water. Nutrient profile information is provided from sediment sample analysis. Based on the data from the horizontal distribution of surface sediment phosphorus in BMR, it was apparent that the highest concentration occurred in the reservoir inlet from Sungai Kurau catchment area. Phosphorus and nitrogen in BMR have a similar trend of decreasing concentration from upstream to downstream. The phosphorus and nitrogen concentrations of surface sediment were in fact significantly correlated with phosphorus and nitrogen concentrations of surface water because of the high value of determination of correlation (R2. As a conclusion, the deposition of sediments was found to bring along external nutrients. Variability of phosphorus and nitrogen concentrations in the sediment directly affects the quality of water which is very important for irrigation and domestic uses.

  13. Light attenuation - a more effective basis for the management of fine suspended sediment than mass concentration?

    Davies-Colley, Robert J; Ballantine, Deborah J; Elliott, Sandy H; Swales, Andrew; Hughes, Andrew O; Gall, Mark P

    2014-01-01

    Fine sediment continues to be a major diffuse pollution concern with its multiple effects on aquatic ecosystems. Mass concentrations (and loads) of fine sediment are usually measured and modelled, apparently with the assumption that environmental effects of sediment are predictable from mass concentrations. However, some severe impacts of fine sediment may not correlate well with mass concentration, notably those related to light attenuation by suspended particles. Light attenuation per unit mass concentration of suspended particulate matter in waters varies widely with particle size, shape and composition. Data for suspended sediment concentration, turbidity and visual clarity (which is inversely proportional to light beam attenuation) from 77 diverse New Zealand rivers provide valuable insights into the mutual relationships of these quantities. Our analysis of these relationships, both across multiple rivers and within individual rivers, supports the proposition that light attenuation by fine sediment is a more generally meaningful basis for environmental management than sediment mass. Furthermore, optical measurements are considerably more practical, being much cheaper (by about four-fold) to measure than mass concentrations, and amenable to continuous measurement. Mass concentration can be estimated with sufficient precision for many purposes from optical surrogates locally calibrated for particular rivers. PMID:24804661

  14. ESTIMATING SUSPENDED SEDIMENT CONCENTRATIONS IN SURFACE WATER OF TRI AN LAKE (VIETNAM) USING LANDSAT MULTISPECTRAL IMAGES

    Hung, Trinh; Tuyen, Vu

    2014-01-01

    Monitoring of suspended sediment is important to maintain water quality and geomorphologic balance. Traditional methods based on field surveys only solve the problem on a small scale. Along with the development of remote sensing technology, satellite images are widely used in the study, analysis of suspended sediment. This article presents a method based on spectral mixture analysis to estimate the suspended sediment concentrations (SSC) in surface water of the Tri An lake from LANDSAT multis...

  15. Sediment-copper distributions in hyper-concentrated turbulent solid-liquid system

    YANG Jun; NI Jin-ren

    2007-01-01

    This study presents a special problem on vertical distribution for sediment and copper in hyper-concentrated turbulent solid-liquid system that is essentially different from the ordinary low-concentrated turbulent system. A resonance type turbulent simulation equipment is used for the experimental study in which a vertically uniform turbulent field of the mixture of loess and water is produced in a testing cylinder with a grille stirrer that moves up and down harmoniously with varying vibration frequencies. In order to compare the variations of the vertical profiles of sediment and copper in low- and hyper-concentrated solid-liquid system, different scenarios for input sediment content ranging from 5 to 800 kg/m3 was considered in the experimental studies. It was found that solids copper content increases with input sediment content, S0, and reaches its peak as S0 goes to 10 kg/m3 and then decreases rapidly with increasing input sediment content. Such a behavior is possibly resulted from the joint effect of the specific adsorption of copper on loess, precipitation of carbonate and hydroxide of copper due to high carbonate content in the loess and the so-called "particulate concentration effect" due to the present of the sediment variation in water. The vertical sediment concentration distribution resulted from the uniform turbulence is generally uniform, but slight non-uniformity does occur as sediment concentration exceeds certain value. However, the vertical concentration distributions of soluble copper seem not affected much by the variation of sediment concentrations.

  16. Comparison of manufactured and black carbon nanoparticle concentrations in aquatic sediments

    Koelmans, A.A.; Nowack, B.; Wiesner, M.

    2009-01-01

    In this paper, we show that concentrations of manufactured carbon-based nanoparticles (MCNPs) in aquatic sediments will be negligible compared to levels of black carbon nanoparticles (BCNPs). This is concluded from model calculations accounting for MCNP sedimentation fluxes, removal rates due to agg

  17. Satellite estimates of wide-range suspended sediment concentrations in Changjiang (Yangtze) estuary using MERIS data

    Shen, F.; Verhoef, W.; Zhou, Y.; Salama, M.S.; Liu, X.

    2010-01-01

    The Changjiang (Yangtze) estuarine and coastal waters are characterized by suspended sediments over a wide range of concentrations from 20 to 2,500 mg l-1. Suspended sediment plays important roles in the estuarine and coastal system and environment. Previous algorithms for satellite estimates of sus

  18. Operational remote sensing mapping of estuarine suspended sediment concentrations (ORMES)

    Sterckx, S; Knaeps, E; Bollen, M.; Trouw, K.; Houthuys, R.

    2006-01-01

    Within the ORMES project a service is developed which provides suspended sediment maps from remote sensing images in an efficient way. Our main test site is a part of the Belgian Scheldt Estuary near Antwerp. A reliable semi-empirical algorithm has been developed to derive near-surface suspended matter maps in an operational way. This algorithm is applied to a series of hyperspectral airborne data obtained at different stages of the tidal cycle. The produced TSM maps showed good agreement wit...

  19. Sediment Metal Concentration Survey Along the Mine-Affected Molonglo River, NSW, Australia.

    Marasinghe Wadige, Chamani P M; Taylor, Anne M; Krikowa, Frank; Maher, William A

    2016-04-01

    Metal concentrations were measured in sediments of the mine-affected Molonglo River to determine current metal concentrations and distribution along the river. Compared with an uncontaminated site at 6.5 km upstream of the Captains Flat mine, sediments collected from the river at ≤12.5 km distance below the mine had a significantly higher percentage of finely divided silt and clay with higher concentrations of cadmium (Cd), copper (Cu), lead (Pb), and zinc (Zn). The measured metal concentrations in the mine affected sites of the river were in the following order: Zn = 697-6818 > Pb = 23-1796 > Cu = 10-628 > Cd = 0.13-8.7 µg/g dry mass. The highest recorded metal concentrations were Cd at 48, Cu at 45, Pb at 240, and Zn at 81 times higher than the background concentrations of these metals in the river sediments. A clear sediment metal-contamination gradient from the mine site to 63 km downstream was established for Cd, Cu, Pb, and Zn in the river sediments. Compared with sediment metal concentrations before a major flood in 2010, only Zn concentrations increased. For all of the mine-affected sites studied, Cd and Zn concentrations exceeded the (ANZECC/ARMCANZ, Australian and New Zealand guidelines for fresh and marine water quality. Australian and New Zealand Environment and Conservation Council/Agriculture and Resource Management Council of Australia and New Zealand, 2000) interim sediment-quality guidelines low values for Cd (1.5 µg/g dry mass) and the high value for Zn (410 µg/g dry mass). Existing metal loads in the riverbed sediments may still be adversely affecting the river infauna. PMID:26795293

  20. Passive sampling methods for contaminated sediments: Scientific rationale supporting use of freely dissolved concentrations

    Mayer, Philipp; Parkerton, Thomas F.; Adams, Rachel G.;

    2014-01-01

    Passive sampling methods (PSMs) allow the quantification of the freely dissolved concentration (Cfree ) of an organic contaminant even in complex matrices such as sediments. Cfree is directly related to a contaminant's chemical activity, which drives spontaneous processes including diffusive upta...

  1. Vertical distribution of 137Cs activity concentration in marine sediments at Amvrakikos Gulf, western of Greece

    The aim of the present work is the study of 137Cs migration in sediment column taking into account the sedimentation rate in the Amvrakikos Gulf, at the western part of Greece. Marine core sediments were collected and the measurements were performed using the high resolution gamma-ray spectrometry method. The vertical distribution of 137Cs activity concentration, as part of anthropogenic marine radioactivity, provided averaged sedimentation rate by identifying the depths of activity concentrations due to the Chernobyl accident and the nuclear tests signals. Furthermore, 137Cs measurements were reproduced using the proposed one-dimensional diffusion–advection model which provides mainly as an output, the sedimentation rate and the average diffusivity of 137Cs in the sediment column. The proposed model estimates the temporal variation of 137Cs activity concentration from 1987 (one year after the Chernobyl accident) till today (2014). - Highlights: • Two sediment cores were studied using 137Cs as a tracer. • Two peaks are observed due to nuclear tests and Chernobyl accident. • Diffusivities, as well as 137Cs apparent sedimentation speeds are estimated

  2. The relationship between suspended sediment concentration and remotely sensed spectral radiance - a review

    Curran, P. J.; Novo, E.

    1988-01-01

    Information on the concentration of suspended sediments in coastal waters is necessary for the understanding and management of the coastal environment. Traditionally, suspended sediment concentration (SSC) has been measured by time-consuming and costly boat surveys which allow the accurate measurement of SSC for single points in space and time. Remote sensing from airborne and spaceborne sensors has proved to be a useful adjunct to such surveys as it provides an instantaneous and synoptic vie...

  3. Metal concentrations in sediment and Nereis diversicolor in two Moroccan lagoons: Khnifiss and Oualidia

    Idardare, Zaina; Chiffoleau, Jean-francois; A. Moukrim; Alla, A.; Auger, Dominique; Lefrere, L; Rozuel, Emmanuelle

    2008-01-01

    Metal concentrations were measured monthly during an annual cycle (December 2004 to January 2006) in the tissues of Nereis diversicolor ragworms and sediment from two Moroccan Atlantic coastal lagoons: Oualidia in the north, situated in a highly industrialised urban area and Khnifiss in the south, far from anthropogenic influences. Relatively high levels of Zn, Ag and Cd were found in the sediment of Oualidia lagoon, while Ni concentrations were shown to be high at Khnifiss. The significant m...

  4. Radiometric dating of sediment core from waterwork reservoir Rozgrund and analysis of mercury concentration depth profile

    Radioisotope dating of lake sediments combined with analysis of chemical properties of the sediment layers allow us to study the history of the human impact on nature. Undisturbed sediment layers in the core samples serve as chronicle database with information about lake ecosystem and surrounding environment in the time of deposition. A sediment core sample from the bottom of the water-work reservoir Rozgrund was collected and separated into 2 cm thick layers. Samples were analysed by HPGe spectrometry for anthropogenous Cs-137 activity. From identified peaks corresponding to nuclear tests and Chernobyl accident the sedimentation rate was calculated and the chronology of layers established. Sub-samples from each layer were prepared separately for the analysis of the Hg concentration by atomic absorption spectrometry. The results show very small variations in Hg concentrations and there is no significant trend present in the profile. (author)

  5. Evaluation of bleach-sedimentation for sterilising and concentrating Mycobacterium tuberculosis in sputum specimens

    Valencia Teresa

    2011-10-01

    Full Text Available Abstract Background Bleach-sedimentation may improve microscopy for diagnosing tuberculosis by sterilising sputum and concentrating Mycobacterium tuberculosis. We studied gravity bleach-sedimentation effects on safety, sensitivity, speed and reliability of smear-microscopy. Methods This blinded, controlled study used sputum specimens (n = 72 from tuberculosis patients. Bleach concentrations and exposure times required to sterilise sputum (n = 31 were determined. In the light of these results, the performance of 5 gravity bleach-sedimentation techniques that sterilise sputum specimens (n = 16 were compared. The best-performing of these bleach-sedimentation techniques involved adding 1 volume of 5% bleach to 1 volume of sputum, shaking for 10-minutes, diluting in 8 volumes distilled water and sedimenting overnight before microscopy. This technique was further evaluated by comparing numbers of visible acid-fast bacilli, slide-reading speed and reliability for triplicate smears before versus after bleach-sedimentation of sputum specimens (n = 25. Triplicate smears were made to increase precision and were stained using the Ziehl-Neelsen method. Results M. tuberculosis in sputum was successfully sterilised by adding equal volumes of 15% bleach for 1-minute, 6% for 5-minutes or 3% for 20-minutes. Bleach-sedimentation significantly decreased the number of acid-fast bacilli visualised compared with conventional smears (geometric mean of acid-fast bacilli per 100 microscopy fields 166, 95%CI 68-406, versus 346, 95%CI 139-862, respectively; p = 0.02. Bleach-sedimentation diluted paucibacillary specimens less than specimens with higher concentrations of visible acid-fast bacilli (p = 0.02. Smears made from bleach-sedimented sputum were read more rapidly than conventional smears (9.6 versus 11.2 minutes, respectively, p = 0.03. Counting conventional acid-fast bacilli had high reliability (inter-observer agreement, r = 0.991 that was significantly reduced (p

  6. Evaluation of suspended sediment concentrations, sediment fluxes and sediment depositions along a reservoir by using laser diffraction and acoustic backscatter data

    Lizano, Laura; Haun, Stefan

    2015-04-01

    The construction of dams and reservoirs disturb the natural morphological behavior of rivers. A natural settling effect occurs due to the reduced turbulences and flow velocities. As a consequence, reservoirs fill up with sediments which results in a reduction of storage volume, influences the operation of hydropower plants and leads in several cases to flood protection problems. The sediment depositions in reservoirs are standardly evaluated by using bathymetric data, obtained by a single beam sonar from pre-defined cross sections or by an extensive evaluation of the reservoir bed by a side scan sonar. However, a disadvantage of this method is that it is not possible to evaluate the pore water content of the depositions, which may lead as consequence to an uncertainty in the measured amount of deposited sediments. Given that a major part of sediments entering reservoirs are transported in suspension, sediment flux measurements along defined transects could give more reliable information on the settled amount of sediments and additional information on the sediment transport mechanism within the reservoir. An evaluation of the sediment fluxes is in practice often conducted by a single suspended sediment concentration (SSC) measurement in combination with a cross sectional calibration factor to take changes in the SSC along the transect into account. However, these calibration factors are often developed only for one specific in-situ condition and may give unreliable results in case that the boundaries change e.g. the hydraulic conditions. Hence an evaluation of the sediment fluxes along the whole transect would give a more reliable number for the amount of transported sediments through the reservoir. This information can afterwards be used to calculate the amount of settled sediments in different sections of the reservoir and the amount of sediments which will enter the intake. For this study the suspended sediment transport within the Peñas Blancas reservoir in

  7. Anthropogenic lead concentrations and sources in Baltic Sea sediments based on lead isotopic composition

    Highlights: • Pb concentrations reach even 147 μg/g at Gdansk Basin sediments. • Marine sediments deposited before 1860 are not contaminated by Pb. • Contemporary inventories of anthropogenic Pb in marine sediments was of 0.5–11 g for m2. • The lowest 206Pb/207Pb (1.165) were measured in sediments deposited between 1970s–90s. • Coal burning was always the most important Pb source in Poland. - Abstract: The Gulf of Gdańsk is influenced by heavy metals of anthropogenic origin. In this study, temporal concentration changes of Pb, Zn, Cd, and Cu were studied in six, 50 cm long sediment cores. The main aim of the study was to concentrate on the history of Pb fluxes and Pb isotopic composition (206Pb/207Pb and 208Pb/206Pb) to trace Pb sources. The lowest Pb concentrations (19 μg g−1) were measured in sediments deposited circa 1860, while the highest Pb concentrations (63–147 μg g−1) were measured in sediments deposited between 1960s and 70s. Pre-industrial Pb fluxes were 7 Pb m2 year−1, while after WWII they reached 199 Pb m2 year−1. Highest 206Pb/207Pb ratios (∼1.22) were measured in the oldest sediment layers, and the lowest 206Pb/207Pb ratios (∼1.165) were measured in the sediments deposited in 1970s–90s. During the period of highest Pb contamination, the anthropogenic Pb fraction reached up to 93%. A general discussion of the Pb sources, emissions, and loads for Poland is included

  8. A geochemical reconnaissance survey of Sri Lanka using panned mineral concentrates of stream sediments

    Thirteen elements (Au, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sn, Th, U and Zn) were determined in 120 heavy mineral concentrates from Sri Lankan stream sediments of the Highland Group of rocks in central Sri Lanka. The data indicate sporadic occurrences of gold, notably in the north of the region where this metal had not previously been found. The possibility of the existence of a previously unknown area of ultramafic rocks near Balangoda close to the plate boundary with the Vijayan Complex was indicated by high levels of chromium and nickel in the sediments. Background levels of uranium (8 μg/g) were relatively high and three anomalies (>35 μg/g) were detected in stream sediment concentrates. The project has pinpointed several areas where localized intensive exploration for specific minerals should be undertaken. Background levels have also been established for thirteen elements in stream sediment concentrates derived from the Highland Group of rocks. (orig.)

  9. Water demand for ecosystem protection in rivers with hyper-concentrated sediment-laden flow

    LUO; Huaming; LI; Tianhong; NI; Jinren; WANG; Yudong

    2004-01-01

    Sediment transport is one of the main concerns in a river system with hyper-concentrated flows. Therefore, the water use for sediment transport must be considered in study on the water demand for river ecosystem. The conventional methods for calculating the Minimum Water Demand for River Ecosystem (MWDRE) are not appropriate for rivers with high sediment concentration. This paper studied the MWDRE in wet season, dry season and the whole year under different water-and-sediment conditions in the Lower Yellow River, which is regarded as a typical river with sediment-laden flows. The characteristics of MWDRE in the river are analyzed. Firstly,the water demand for sediment transport (WDST) is much larger than the demands for other riverine functions, the WDST accounts for the absolute majority of the MWDRE.Secondly, in wet season when the WDST is satisfied, not only most of the annual incoming sediment can be transported downstream, but also the water demands for other river functions can be satisfied automatically, so that the MWDRE in wet season is identical to the WDST. Thirdly, in dry season, when the WDST is satisfied, the water demands for other river functions can also be satisfied, but the low sediment transport efficiency results in significant waste of water resources. According to these characteristics and aiming at decreasing sediment deposition in the riverbed and improving the utilization efficiency of water resources, hydrological engineering works can be used to regulate or control flow and sediment so that the sediment incoming in dry season can be accumulated and be transported downstream intensively and thus efficiently in wet season.

  10. Water Quality and Heavy Metal Concentrations in Sediment of Sungai Kelantan, Kelantan, Malaysia: A Baseline Study

    A study on water quality and heavy metal concentration in sediment at selected sites of Sungai Kelantan was carried out. Ten water samples were collected along the river for physical and chemical analysis and twenty-six water and sediment samples were collected for heavy metal analysis. Water was sampled at three different dates throughout the study period whereas sediments were collected once. In addition to heavy metal analysis, sediment samples were also analysed for texture, ph and organic content. The physical and chemical water quality analyses were carried out according to the ALPHA procedures. Result of water quality analysis (physico-chemical) indicated that Sungai Kelantan is characterised by excellent water quality and comparable to pristine ecosystems such as the National Park and Kenyir Lake. This river was classified into class I - class III based on Malaysian interim water quality standard criteria (INWQS). Heavy metals Pb, Zn, Cu and Cd was detected at low concentration in sediment samples, except for Fe and Mn. The presence of Fe and Mn in sediment samples was though to be of natural origin from the soil. Anthropogenic metal concentrations in sediment were low indicating that Sungai Kelantan has not experienced extreme pollution. (author)

  11. Acetate, lactate, propionate, and isobutyrate as electron donors for iron and sulfate reduction in Arctic marine sediments, Svalbard

    Finke, Niko; Vandieken, Verona; Jørgensen, Bo Barker

    2007-01-01

    oxidized (0-2 cm) and the reduced (5-9 cm) zone. In the 0-2 cm layer, 2/3 of the mineralization could be attributed to sulfate reduction and 1/3 to iron reduction. In the 5-9 cm layer, sulfate reduction was the sole mineralization process. Acetate and lactate turnover rates were measured by radiotracer....... Inhibition of sulfate reduction with selenate resulted in the accumulation of acetate, propionate, and isobutyrate. The acetate turnover rates determined by radiotracer and accumulation after inhibition were similar. VFA turnover accounted for 21% and 52% of the mineralization through sulfate reduction in...... the 0-2 and 5-9 cm layer, respectively. Acetate and lactate turnover in the inhibited 0-2 cm slurry was attributed to iron reduction and accounted for 10% and 2% of the iron reduction. Therefore, 88% and 79% of the iron and sulfate reduction in the 0-2 cm layer, respectively, must be fueled by...

  12. Background concentrations of radionuclides in soils and river sediments in northern New Mexico, 1974-1986

    Purtymun, W.D.; Peters, R.J.; Buhl, T.E.; Maes, M.N.; Brown, F.H.

    1987-11-01

    This report documents the range and the upper limit for background concentrations of radionuclides and radioactivity in soils and river sediments that occur as natural rock-forming minerals and worldwide fallout from atmospheric nuclear weapons tests. Documentation is based on the collection of soil and sediment in northern New Mexico and analyzed for /sup 137/Cs, /sup 238/Pu, /sup 239,240/Pu, /sup 90/Sr, total uranium, gross gamma, and tritium. The data used to establish the statistical range and upper limit of background concentration cover a 9- or 13-year period ending in 1986. The knowledge of background levels is necessary to interpret soil and sediment data collected for the annual environmental surveillance report and other reports relating to radionuclides or radioactivity in soils and sediments. 11 refs., 1 fig., 5 tabs.

  13. PAHs concentration and toxicity in organic solvent extracts of atmospheric particulate matter and sea sediments.

    Ozaki, Noriatsu; Takeuchi, Shin-ya; Kojima, Keisuke; Kindaichi, Tomonori; Komatsu, Toshiko; Fukushima, Takehiko

    2012-01-01

    The concentration of polycyclic aromatic hydrocarbons (PAHs) and the toxicity to marine bacteria (Vibrio fischeri) were measured for the organic solvent extracts of sea sediments collected from an urban watershed area (Hiroshima Bay) of Japan and compared with the concentrations and toxicity of atmospheric particulate matter (PM). In atmospheric PM, the PAHs concentration was highest in fine particulate matter (FPM) collected during cold seasons. The concentrations of sea sediments were 0.01-0.001 times those of atmospheric PM. 1/EC50 was 1-10 L g(-1) PM for atmospheric PM and 0.1-1 L g(-1) dry solids for sea sediments. These results imply that toxic substances from atmospheric PM are diluted several tens or hundreds of times in sea sediments. The ratio of the 1/EC50 to PAHs concentration ((1/EC50)/16PAHs) was stable for all sea sediments (0.1-1 L μg(-1) 16PAHs) and was the same order of magnitude as that of FPM and coarse particulate matter (CPM). The ratio of sediments collected from the west was more similar to that of CPM while that from the east was more similar to FPM, possibly because of hydraulic differences among water bodies. The PAHs concentration pattern analyses (principal component analysis and isomer ratio analysis) were conducted and the results showed that the PAHs pattern in sea sediments was quite different to that of FPM and CPM. Comparison with previously conducted PAHs analyses suggested that biomass burning residues comprised a major portion of these other sources. PMID:22797225

  14. Concentration of 134Cs + 137Cs bonded to the organic fraction of sediments offshore Fukushima, Japan

    We conducted a sequential chemical extraction experiment for radiocesium (134Cs + 137Cs) using 21 surface sediment samples and two sets of size-fractionated surface sediment samples collected offshore Fukushima. Our results support earlier reports in this area that organic substances in marine sediments have an apparently higher preference for radiocesium than mineral substances. Observations suggest that mineral and organic substances in the marine sediments offshore Fukushima have the same order of preference for radiocesium, primarily because of the existence of ionic competitors in seawater. The apparent preference of radiocesium for organic material is greater because of the partial coverage of sediment mineral surfaces by organic substances. By using these relationships, we created a 2-D map of radiocesium concentration in sediment organic fraction in offshore-Fukushima region. Combining our results with existing monitoring data of marine benthos in offshore-Fukushima sediments, we estimated a transfer coefficient of radiocesium from sediment organic materials to benthic polychaetes as less than 0.03-0.008. (author)

  15. Textural characteristics and heavy metal concentrations in billabong sediments from the Magela Creek System, Northern Australia

    The objective of this study was to assess the usefulness of Magela Creek billabong sediments to monitor the potential buildup in heavy metals as a result of the Ranger uranium mining operation and the regional township at Jabiru. Major differences were found in the physical characteristics of the sediments both between billabongs and, in some cases, within the same billabong. The sediments in the backflow billabongs were fine-grained, being mostly silt and clay, and rich in organic matter (approx. 20%). The floodplain billabongs also contained predominantly fine-grained sediments but the organic content was considerably lower (6 to 7%). A large number of sediments from Magela Creek billabongs were analysed for iron, manganese, cadmium, copper, chromium, lead, zinc and mercury. From these data three main points emerge: (i) The concentrations of all metals in the less than 63 μm fraction are very low when compared with published values for unpolluted sediments. (ii) The metals were evenly distributed over fractions less than 63 μm in size. (iii) A digestion procedure involving extraction of the sediments with H2O2 and HNO3 has proved to be most effective. Comparison with the results obtained using a complete digestion procedure (H2O2/HNO3/HF) showed that most of the chromium (63%), much of the zinc (46%), but only 25 to 36% of the iron, manganese, copper and lead were associated with the mineral phase of the sediments and would be unavailable to the biota

  16. Assessment of Suspended Sediments Concentration in Surface Waters, Using Modis Images

    Mobasheri M. Reza

    2008-01-01

    Remote sensing from air-borne and space-borne sensors have proved to be a useful method for Suspended Sediment Concentration (SSC) estimation as it provides an instantaneous and synoptic view of suspended sediments that would otherwise be unavailable. The reason for the success of remote sensing in such surveys is the strong positive relationship that exists between SSC and remotely sensed water leaving radiance. To find an algorithm relating SSC to spectral radiance&#...

  17. MODELING OF THE HIGH CONCENTRATION LAYER OF COHESIVE SEDIMENT UNDER THE ACTION OF WAVES AND CURRENTS

    Qinghe ZHANG; Yongsheng WU; Jijian LIAN; Pingxing DING

    2001-01-01

    High concentration layer of cohesive sediment frequently occurs in muddy estuaries and coastal zones, and causes rapid siltation of the waterways. A one dimensional vertical coupled model describing the interactions between waves, currents and suspended cohesive sediment is developed in the present paper. The numerical results and analyses with field measurements reveal the mechanism of the formation and transport behaviors of the layer under the action of waves and currents.

  18. Metal concentrations in stream biofilm and sediments and their potential to explain biofilm microbial community structure

    Concentrations of metals associated with sediments have traditionally been analysed to assess the extent of heavy metal contamination in freshwater environments. Stream biofilms present an alternative medium for this assessment which may be more relevant to the risk incurred by stream ecosystems as they are intensively grazed by aquatic organisms at a higher trophic level. Therefore, we investigated zinc, copper and lead concentrations in biofilms and sediments of 23 stream sites variously impacted by urbanisation. Simultaneously, biofilm bacterial and ciliate protozoan community structure was analysed by Automated Ribosomal Intergenic Spacer Analysis and Terminal Restriction Fragment Length Polymorphism, respectively. Statistical analysis revealed that biofilm associated metals explained a greater proportion of the variations observed in bacterial and ciliate communities than did sediment associated-metals. This study suggests that the analysis of metal concentrations in biofilms provide a good assessment of detrimental effects of metal contaminants on aquatic biota. - Highlights: ► Zn, Cu and Pb concentrations in biofilm and sediments from 23 streams were assessed. ► Bacteria and ciliate protozoa were simultaneously used as biological indicators. ► Zn and Cu were generally enriched in biofilm compared to sediments. ► Metals in biofilm provide a useful assessment of freshwater ecosystem contamination. ► Results highlight the likely ecological importance of biofilm associated metals. - Metal concentrations in stream biofilms provide a good assessment of the effects of trace metal contaminants on freshwater ecosystems.

  19. ANN modelling of sediment concentration in the dynamic glacial environment of Gangotri in Himalaya.

    Singh, Nandita; Chakrapani, G J

    2015-08-01

    The present study explores for the first time the possibility of modelling sediment concentration with artificial neural networks (ANNs) at Gangotri, the source of Bhagirathi River in the Himalaya. Discharge, rainfall and temperature have been considered as the main controlling factors of variations in sediment concentration in the dynamic glacial environment of Gangotri. Fourteen feed forward neural networks with error back propagation algorithm have been created, trained and tested for prediction of sediment concentration. Seven models (T1-T7) have been trained and tested in the non-updating mode whereas remaining seven models (T1a-T7a) have been trained in the updating mode. The non-updating mode refers to the scenario where antecedent time (previous time step) values are not used as input to the model. In case of the updating mode, antecedent time values are used as network inputs. The inputs applied in the models are either the variables mentioned above as individual factors (single input networks) or a combination of them (multi-input networks). The suitability of employing antecedent time-step values as network inputs has hence been checked by comparative analysis of model performance in the two modes. The simple feed forward network has been improvised with a series parallel non-linear autoregressive with exogenous input (NARX) architecture wherein true values of sediment concentration have been fed as input during training. In the glacial scenario of Gangotri, maximum sediment movement takes place during the melt period (May-October). Hence, daily data of discharge, rainfall, temperature and sediment concentration for five consecutive melt periods (May-October, 2000-2004) have been used for modelling. High Coefficient of determination values [0.77-0.88] have been obtained between observed and ANN-predicted values of sediment concentration. The study has brought out relationships between variables that are not reflected in normal statistical analysis. A

  20. Evaluation of ADCP backscatter inversion to suspended sediment concentration in estuarine environments

    Park, Hyo-Bong; Lee, Guan-hong

    2016-03-01

    Acoustic Doppler Current Profilers (ADCP), designed for measuring velocity profiles, are widely used for the estimation of suspended sediment concentration from acoustic backscatter strength, but its application to estuarine environments requires further refinement. In this study, we examined the inversion capability of two ADCPs with 600 and 1200 kHz in three Korean estuaries: the supra-macrotidal Han River Estuary (HRE), microtidal Nakdong River Estuary (NRE), and anthropogenically altered macrotidal Yeongsan River Estuary (YRE). In particular, we examined the relative importance of the sound attenuations due to water (αw) and sediment (αs) in response to sediment characteristics (size and concentration) as well as changing salinity and temperature. The inverted concentration was compared with reference concentrations obtained either from water samples or Optical Backscatter Sensors. In NRE and YRE, where suspended sediment concentrations were less than 0.2 g/l, the acoustic inversion performed poorly only with αs (r = 0.20 and 0.38 for NRE and YRE, respectively), but well with αw (r = 0.66 and 0.42 for NRE and YRE, respectively). Thus, it is important to accurately constrain αw in low-concentration estuarine environments. However, we did not find that the varying αw performed considerably better than the constant αw. On the other hand, the acoustic inversion was poorest at HRE regardless of αw and αs (r = 0.71 and mean relative error = 45%). The large discrepancy appears to result from the poorly constrained, spatially and temporally varying sediment characteristics (grain size, density and concentration) due to non-local sediment transport in the macrotidal HRE.

  1. Acoustic observations of near-bed sediment concentration and flux statistics above migrating sand dunes

    Wilson, G. W.; Hay, A. E.

    2016-06-01

    A coherent Doppler profiler was used to measure coincident time series of velocity (u,w), sediment mass concentration (c), and sediment grain size (d), above mobile sand dunes in unidirectional flow (˜1 m/s, ˜1 m water depth). The measurements are used to extract statistical distributions of sediment concentration and flux just above the bed. Observed mass fluxes (uc,wc) were well fit by quasi-exponential distributions, at all positions along the dune profile, similar to previous observations of single-particle momenta for bed load over flat beds. Observed concentrations of moving particles were well fit by negative-binomial distributions, also similar to previous observations over flat beds. These probability distributions relate to two recent stochastic theories, previously derived and verified for uniform flow over flat beds. It is hypothesized that these theories may also be used as a local approximation in natural-scale flows with bed forms.

  2. Assessment of Suspended Sediments Concentration in Surface Waters, Using Modis Images

    Mobasheri M. Reza

    2008-01-01

    Full Text Available Remote sensing from air-borne and space-borne sensors have proved to be a useful method for Suspended Sediment Concentration (SSC estimation as it provides an instantaneous and synoptic view of suspended sediments that would otherwise be unavailable. The reason for the success of remote sensing in such surveys is the strong positive relationship that exists between SSC and remotely sensed water leaving radiance. To find an algorithm relating SSC to spectral radiance over Bahmansheer River Estuary at the North-West of Persian Gulf, a three-month field expedition (April to June 2003 was conducted while the MODIS sensor on board Terra simultaneously flew over the scene. Fifty seven samples in fifteen trips were collected. The collected samples were analyzed by measuring concentration, diameters of the sediment particles and by determining the sediment constituents. Total concentration ranged between 30 and 500 mg, the range of particle diameter was from less than a micrometer to more than 20 micrometers and finally it was found that the sediment was composed of Quartz, Kaolinite, Orthoclase, Chlorite, Calcite, Gypsum, Muscovite, Halite, Anhydrite, Apatite, Biotite and a low amount of Albite. It is found that the spectral characteristics of these compositions are partly responsible for the reflected and/or scattered energy in different bands while the correlation between larger suspended particle concentration and spectral radiance was profound.

  3. Indole-3-acetic acid-induced oxidative burst and an increase in cytosolic calcium ion concentration in rice suspension culture.

    Nguyen, Hieu T H; Umemura, Kenji; Kawano, Tomonori

    2016-08-01

    Indole-3-acetic acid (IAA) is the major natural auxin involved in the regulation of a variety of growth and developmental processes such as division, elongation, and polarity determination in growing plant cells. It has been shown that dividing and/or elongating plant cells accompanies the generation of reactive oxygen species (ROS) and a number of reports have suggested that hormonal actions can be mediated by ROS through ROS-mediated opening of ion channels. Here, we surveyed the link between the action of IAA, oxidative burst, and calcium channel activation in a transgenic cells of rice expressing aequorin in the cytosol. Application of IAA to the cells induced a rapid and transient generation of superoxide which was followed by a transient increase in cytosolic Ca(2+) concentration ([Ca(2+)]c). The IAA-induced [Ca(2+)]c elevation was inhibited by Ca(2+) channel blockers and a Ca(2+) chelator. Furthermore, ROS scavengers effectively blocked the action of IAA on [Ca(2+)]c elevation. PMID:27149194

  4. The effect of undissociated acetic-acid concentration of buffer solutions on artificial caries-like lesion formation in human tooth enamel

    Groeneveld, A.; Theuns, H.M.; Dijk, J.W.E. van; Driessens, F.C.M.

    1984-01-01

    A chemical system for lesion production was used. The influence on lesion characteristics of the concentration of undissociated acetic acid in a calcium and phosphate-containing buffer solution was investigated. Artificial lesions obtained after demineralization in buffers with a pH of 4.0, 4.5, 5.0

  5. Antifoulant (butyltin and copper) concentrations in sediments from the Great Barrier Reef World Heritage Area, Australia

    Antifoulant concentrations are generally low in the Great Barrier Reef, although ship grounding sites present a previously unidentified significant source of antifoulant pollutants in the Great Barrier Reef. - Antifoulant concentrations were determined in marine sediments collected from commercial harbours, marinas, mooring locations on mid-shelf continental islands, and outer reef sites in four regions within the Great Barrier Reef World Heritage Area in 1999. Highest copper concentrations were present in sediments collected from commercial harbour sampling sites (28-233 μg Cu g-1 dry wt.). In contrast, copper concentrations in sediments collected from boat mooring sites on mid-shelf continental islands and outer reef sites were at background concentrations (i.e. -1 dry wt.). Butyltin was only detectable in four of the 42 sediments sampled for analysis, and was only present in sediments collected from commercial harbours (18-1275 ng Sn g-1 dry wt.) and from marinas (4-5 ng Sn g-1 dry wt.). The detection of tributyltin at marina sites implies that this antifoulant may continue to be used illegally on the hulls of smaller recreational vessels. Sediment samples were also collected opportunistically from the site of a 22,000 t cargo ship grounding in May 1999 at Heath Reef, in the far northern Great Barrier Reef. Butyltin concentrations were grossly elevated (660-340,000 ng Sn g-1 dry wt.) at the grounding site. The impact of residual antifoulants at large ship grounding sites should be recognised as a significant, long-term environmental problem unless antfoulant clean-up strategies are undertaken

  6. SIMULATION OF LOW-CONCENTRATION SEDIMENT-LADEN FLOW BASED ON TWO-PHASE FLOW THEORY

    2007-01-01

    Low concentration sediment-laden flow is usually involved in water conservancy, environmental protection, navigation and so on. In this article, a mathematical model for low-concentration sediment-laden flow was suggested based on the two-phase flow theory, and a solving scheme for the mathematical model in curvilinear grids was worked out. The observed data in the Zhang River in China was used for the verification of the model, and the calculated results of the water level, velocity and river bed deformation are in agreement with the observed ones.

  7. Degradation of fipronil in anaerobic sediments and the effect on porewater concentrations.

    Brennan, Amanda A; Harwood, Amanda D; You, Jing; Landrum, Peter F; Lydy, Michael J

    2009-09-01

    The current study measured the degradation of fipronil in laboratory-spiked silt loam sediment under anaerobic conditions at different aging times. The half-life of fipronil in anaerobic sediments spiked at 5.8+/-0.049 and 21+/-1.4microg/kg dry weight (dw) was 21+/-0.22 and 15+/-0.11d, respectively. Fipronil-sulfide was the primary degradation product with fipronil-sulfone detected at lower concentrations. No degradation occurred to fipronil-sulfide and fipronil-sulfone over 200d in separate systems. A concurrent decline in sediment concentrations resulted in a decline of fipronil in sediment porewater with an increase in fipronil-sulfide and fipronil-sulfone measured by matrix-solid phase microextraction (matrix-SPME). Equilibrium among sediment, porewater, and matrix-SPME fiber occurred within 138d for fipronil and fipronil-sulfone; however, fipronil-sulfide did not reach equilibrium during the test, and modeling predicted upwards of 1083d to reach equilibrium. Regardless of the time to reach equilibrium, the rapid degradation of fipronil has little ecological significance given that fipronil-sulfide and fipronil-sulfone have equal or greater toxicity, and exhibit greater environmental stability in both the sediment and porewater, thereby becoming bioavailable. PMID:19576615

  8. Well-constructed cellulose acetate membranes for forward osmosis: Minimized internal concentration polarization with an ultra-thin selective layer

    Zhang, Sui

    2010-09-01

    The design and engineering of membrane structure that produces low salt leakage and minimized internal concentration polarization (ICP) in forward osmosis (FO) processes have been explored in this work. The fundamentals of phase inversion of cellulose acetate (CA) regarding the formation of an ultra-thin selective layer at the bottom interface of polymer and casting substrate were investigated by using substrates with different hydrophilicity. An in-depth understanding of membrane structure and pore size distribution has been elucidated with field emission scanning electronic microscopy (FESEM) and positron annihilation spectroscopy (PAS). A double dense-layer structure is formed when glass plate is used as the casting substrate and water as the coagulant. The thickness of the ultra-thin bottom layer resulted from hydrophilic-hydrophilic interaction is identified to be around 95nm, while a fully porous, open-cell structure is formed in the middle support layer due to spinodal decomposition. Consequently, the membrane shows low salt leakage with mitigated ICP in the FO process for seawater desalination. The structural parameter (St) of the membrane is analyzed by modeling water flux using the theory that considers both external concentration polarization (ECP) and ICP, and the St value of the double dense-layer membrane is much smaller than those reported in literatures. Furthermore, the effects of an intermediate immersion into a solvent/water mixed bath prior to complete immersion in water on membrane formation have been studied. The resultant membranes may have a single dense layer with an even lower St value. A comparison of fouling behavior in a simple FO-membrane bioreactor (MBR) system is evaluated for these two types of membranes. The double dense-layer membrane shows a less fouling propensity. This study may help pave the way to improve the membrane design for new-generation FO membranes. © 2010 Elsevier B.V.

  9. Minimal inhibitory concentrations of undissociated lactic, acetic, citric and propionic acid for Listeria monocytogenes under conditions relevant to cheese.

    Wemmenhove, Ellen; van Valenberg, Hein J F; Zwietering, Marcel H; van Hooijdonk, Toon C M; Wells-Bennik, Marjon H J

    2016-09-01

    Minimal inhibitory concentrations (MICs) of undissociated lactic acid were determined for six different Listeria monocytogenes strains at 30 °C and in a pH range of 4.2-5.8. Small increments in pH and acid concentrations were used to accurately establish the growth/no growth limits of L. monocytogenes for these acids. The MICs of undissociated lactic acid in the pH range of 5.2-5.8 were generally higher than at pH 4.6 for the different L. monocytogenes strains. The average MIC of undissociated lactic acid was 5.0 (SD 1.5) mM in the pH range 5.2-5.6, which is relevant to Gouda cheese. Significant differences in MICs of undissociated lactic acid were found between strains of L. monocytogenes at a given pH, with a maximum observed level of 9.0 mM. Variations in MICs were mostly due to strain variation. In the pH range 5.2-5.6, the MICs of undissociated lactic acid were not significantly different at 12 °C and 30 °C. The average MICs of undissociated acetic acid, citric acid, and propionic acid were 19.0 (SD 6.5) mM, 3.8 (SD 0.9) mM, and 11.0 (SD 6.3) mM, respectively, for the six L. monocytogenes strains tested in the pH range 5.2-5.6. Variations in MICs of these organic acids for L. monocytogenes were also mostly due to strain variation. The generated data contribute to improved predictions of growth/no growth of L. monocytogenes in cheese and other foods containing these organic acids. PMID:27217360

  10. Predicting pollutant concentrations in the water column during dredging operations: Implications for sediment quality criteria.

    Wasserman, Julio Cesar; Wasserman, Maria Angélica V; Barrocas, Paulo Rubens G; Almeida, Aline Mansur

    2016-07-15

    The development of new dredging techniques that can reduce, or at least predict, the environmental impacts, is in high demand by governments in developing countries. In the present work, a new methodology was developed, to evaluate the level of metals contamination (i.e. cadmium, lead and zinc) of the water column, during a dredging operation. This methodology was used to evaluate the impacts of the construction of a new maritime terminal in Sepetiba Bay, Brazil. The methodology quantifies the amount of resuspended sediments and calculates the expected contaminants concentrations in the water column. The results indicated that sediment quality criteria were not compatible with water quality criteria, because the dredging of contaminated sediments does not necessarily yield contaminated water. It is suggested that the use of sediment quality criteria for dredging operations might be abandoned, and the methodology presented in this study applied to assess dredging's environmental impacts, predicting water contamination levels. PMID:27216043

  11. Assessment of metal concentrations in sediment samples from Billings reservoir, Rio Grande tributary, Sao Paulo, Brazil

    The present study chemically characterized sediment samples from the Billings reservoir, Rio Grande tributary, in the Metropolitan region of Sao Paulo, by determining metal concentration and other elements of interest. The chosen chemical parameters for this characterization were Aluminum, Arsenic, Barium, Cadmium, Copper, Chromium, Iron, Lead, Manganese, Mercury, Nickel, Selenium and Zinc. These parameters are also used in the water quality index, with the exception of Selenium. The concentrations were determined through different analytical techniques such as atomic absorption spectrometry (FAAS, GFAAS and CVAAS), optical emission spectrometry (ICP OES) and neutron activation analysis. These analytical methodologies were assessed for precision, accuracy and detection and/or quantification limits for the sediment elements in question. Advantages and disadvantages of each technique for each element and its concentration were also discussed. From these assessment the most adequate technique was selected for the routine analysis of sediment samples for each element concentration determination. This assessment verified also that digestion in a closed microwave system with nitric acid is efficient for the evaluation of extracted metals of environmental interest. The analytical techniques chosen were equally efficient for metals determination. In the case of Cd and Pb, the FAAS technique was selected due to better results than ICP OES, as it does not present matrix interference. The concentration values obtained for metals As, Cd, Cu, Cr, Hg, Ni, Pb and Zn in the sediment samples were compared to Canadian Council of Minister of the Environment (CCME) TEL and PEL values. (author)

  12. Assessment of metal concentrations in sediment samples from Billings Reservoir, Rio Grande tributary, Sao Paulo, Brazil

    The present study chemically characterized sediment samples from the Billings reservoir, Rio Grande tributary, in the Metropolitan region of Sao Paulo, by determining metal concentration and other elements of interest. The chosen chemical parameters for this characterization were Aluminum, Arsenic, Barium, Cadmium, Copper, Chromium, Iron, Lead, Manganese, Mercury, Nickel, Selenium and Zinco. These parameters are also used in the water quality index, with the exception of Selenium. The concentrations were determined through different analytical techniques such as atomic absorption spectrometry (FAAS, GFAAS and CVAAS), optical emission spectrometry (ICP OES) and neutron activation analysis. These analytical methodologies were assessed for precision, accuracy and detection and/or quantification limits for the sediment elements in question. Advantages and disadvantages of each technique for each element and its concentration were also discussed. From these assessments the most adequate technique was selected for the routine analysis of sediment samples for each element concentration determination. This assessment verified also that digestion in a closed microwave system with nitric acid is efficient for the evaluation of extracted metals of environmental interest. The analytical techniques chosen were equally efficient for metals determination. In the case of Cd and Pb, the FAAS technique was selected due to better results than ICP OES, as it does not present matrix interference. The concentration values obtained for metals As, Cd, Cu, Cr, Hg, Ni, Pb and Zn in the sediment samples were compared to Canadian Council of Minister of the Environment (CCME) TEL and PEL values. (author)

  13. A catchment-wide assessment of bed sediment metal concentrations in the first industrial city

    Hurley, Rachel; Rothwell, James; Woodward, Jamie

    2016-04-01

    Manchester is often heralded as the 'first industrial city'. Rapid industrialisation in the 18th and 19th centuries saw vast quantities of fine-grained sediments (e.g. boiler ash and cinders) and contaminants (e.g. dyes, bleaches, and chemicals) deposited into the river channels of the Irwell and Mersey in a manner largely unchecked until the 1970s. Although water quality has improved in recent decades, there is a paucity of information on fluvial sediment quality and the extent to which a legacy of historical contamination persists in the contemporary river network. Forty five sites were sampled across the Irwell and Mersey catchments during low flow conditions in spring/summer 2015. Fine-grained bed sediment was collected using the Lambert and Walling (1988) method. Wet sieving was used to isolate the <63 μm fraction for geochemical analysis. Heavy metal concentrations were obtained via XRF with a particular focus on As, Cr, Cu, Pb and Zn. In order to explore controls on sediment-associated metal concentrations, additional characteristics of the bed sediment were also investigated, including particle size and organic matter content. Enrichment factors, based on mean concentrations obtained from pre-industrial floodplain deposits, were calculated. The enrichment factors reveal severe or very severe metal contamination across the whole catchment, including the headwater basins. Relationships between bed sediment quality and hotspots of historic industrial activity have been examined - these reveal complex spatial patterns associated with the high number and variety of historic contaminant inputs. These data form the first baseline assessment and will be used within a larger project investigating the impact of extreme hydrological events on bed sediment quality and transfer in these catchments.

  14. Differences in nutrient concentrations and resources between seagrass communities on carbonate and terrigenous sediments in South Sulawesi, Indonesia

    Erftemeijer, P.L.A.

    1994-01-01

    Water column, sediment and plant parameters were studied in six tropical seagrass beds in South Sulawesi, Indonesia, to evaluate the relation between seagrass bed nutrient concentrations and sediment type. Coastal seagrass beds on terrigenous sediments had considerably higher biomass of phytoplankto

  15. Sediment suspension in oscillatory flow: measurements of instantaneous concentration at high shear

    Staub, Carsten; Jonsson, Ivar G; Svendsen, Ib A.

    Different syphon type suspended load probes were used together with a specially developed ''carousel'' sampler for measurements of the instantaneous sediment concentration in turbulent oscillatory flow over a sand bed, Shields parameters were well above the ripple/flat bed transition region...

  16. Interannual heavy element and nutrient concentration trends in the top sediments of Venice Lagoon (Italy)

    Highlights: • Heavy element concentrations in sediments of a transitional system were studied. • Element contamination in the recent years has generally declined. • Mercury and cadmium contamination still remain above the limits in hot spots. • The role of sediment resuspension due to anthropogenic activity is discussed. • A basic knowledge to assess the impact of the MOSE construction is provided. - Abstract: The elemental composition of surficial sediments of Venice Lagoon (Italy) in 1987, 1993, 1998 and 2003 were investigated. Zn and Cr concentrations resulted in higher than background levels, but only Cd and Hg were higher than legal quality standards (Italian Decree 2010/260 and Water Framework Directive 2000/60/EC). Contaminants with similar spatial distribution are sorted into three groups by means of correlation analysis: (i) As, Co, Cd, Cu, Fe, Pb, Zn; (ii) Ni, Cr; (iii) Hg. Interannual concentrations are compared by applying a factor analysis to the matrix of differences between subsequent samplings. A general decrease of heavy metal levels is observed from 1987 to 1993, whereas particularly high concentrations of Ni and Cr are recorded in 1998 as a consequence of intense clam fishing, subsequently mitigated by better prevention of illegal harvesting. Due to the major role played by anthropogenic sediment resuspension, bathymetric variations are also considered

  17. Impact of urbanization on the concentrations and distribution of organic contaminants in boreal lake sediments.

    Honkonen, Olga; Rantalainen, Anna-Lea

    2013-02-01

    The main goal of this study was to evaluate the impacts of a middle-sized Finnish urban area on the quality of sediments in an adjacent boreal lake. We investigated the sources and distribution of organic pollutants (polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs)) in the sediments from urban stormwater traps and from Lake Vesijärvi. Grab surface sediment samples were taken from Lake Vesijärvi at various distances (25-2,000 m) from four major stormwater drainage outlets and at 15 urban stormwater traps in areas with different degrees of urbanization. These samples were analysed for 16 PAHs and 28 PCBs with gas chromatography-mass spectrometry. The concentrations of pollutants in the lake sediments were elevated in the vicinity of the urban shore (∑PAH 3-16, ∑PCB up to 0.02-0.3 mg/kg dw) and decreased as a function of distance (∑PAH 0.1-2.5, ∑PCB 0.01-0.3 mg/kg dw at a distance of more than 500 m from the shore), whereas contamination levels in suburban areas were notably lower (∑PAH 0.1-3, ∑PCB trap sediments contained predominantly asphalt-derived PAHs due to pulverized pavement. PAHs in lake sediments were of pyrogenic origin, including the combustion of gasoline, diesel and coal. Suggested pathways of lake contamination are urban runoff discharge, boat traffic and atmospheric deposition. PMID:22527470

  18. EFFECTS OF FEED CONCENTRATION AND WATER VAPOR ON CATALYTIC COMBUSTION OF ETHYL ACETATE AND BENZENE IN AIR OVER CR-ZSM-5 CATALYST

    Ahmad Zuhairi Abdullah

    2010-09-01

    Full Text Available Catalytic combustion of ethyl acetate (EAc and benzene (Bz over chromium exchanged ZSM-5 (Si/Al=240 is reported. An 11 mm i.d. fixed-bed catalytic reactor, operated at temperatures between 100 oC and 500 oC, and under excess oxygen condition, was used for the catalytic activity measurement. Apparent order of reaction and apparent activation energy were determined by operating the reactor differentially at a gas hourly space velocity (GHSV of 78,900 h-1 and feed concentrations between 3,500 ppm to 17,700 ppm and 3,700 to 12,400 ppm for ethyl acetate and benzene, respectively. Ethyl acetate was more reactive than benzene due to highly reactive carbonyl group in the molecule. The combustion process satisfactorily fitted pseudo first-order kinetics with respect to organic concentration and a zero-order dependence on the oxygen concentration. The presence of water vapor (9,000 ppm in the feed stream was found to weaken the reactivity of these organics which could also be demonstrated with increases in the activation energy from 23.1 kJ/mole to 37.6 kJ/mole for ethyl acetate and from 27.6 kJ/mole to 46.1 kJ/mole for benzene. Water vapor was found to play a positive role in the formation of carbon dioxide yield in ethyl acetate combustion. Deactivation of catalyst by water appeared to be only temporary and the activity reverted back to its original value once the source of water vapor was removed.

  19. Uranium series isotopes concentration in sediments at San Marcos and Luis L. Leon reservoirs, Chihuahua, Mexico

    Spatial and temporal distribution of the radioisotopes concentrations were determined in sediments near the surface and core samples extracted from two reservoirs located in an arid region close to Chihuahua City, Mexico. At San Marcos reservoir one core was studied, while from Luis L. Leon reservoir one core from the entrance and another one close to the wall were investigated. 232Th-series, 238U-series, 40K and 137Cs activity concentrations (AC, Bq kg−1) were determined by gamma spectrometry with a high purity Ge detector. 238U and 234U ACs were obtained by liquid scintillation and alpha spectrometry with a surface barrier detector. Dating of core sediments was performed applying CRS method to 210Pb activities. Results were verified by 137Cs AC. Resulting activity concentrations were compared among corresponding surface and core sediments. High 238U-series AC values were found in sediments from San Marcos reservoir, because this site is located close to the Victorino uranium deposit. Low AC values found in Luis L. Leon reservoir suggest that the uranium present in the source of the Sacramento – Chuviscar Rivers is not transported up to the Conchos River. Activity ratios (AR) 234U/238U and 238U/226Ra in sediments have values between 0.9–1.2, showing a behavior close to radioactive equilibrium in the entire basin. 232Th/238U, 228Ra/226Ra ARs are witnesses of the different geological origin of sediments from San Marcos and Luis L. Leon reservoirs

  20. Uranium series isotopes concentration in sediments at San Marcos and Luis L. Leon reservoirs, Chihuahua, Mexico

    Méndez-García, C.; Montero-Cabrera, M. E., E-mail: elena.montero@cimav.edu.mx [Centro de Investigación en Materiales Avanzados, CIMAV, Miguel de Cervantes 120, 31109, Chihuahua, Chihuahua (Mexico); Renteria-Villalobos, M. [Facultad de Zootecnia y Ecología Universidad Autónoma de Chihuahua, Periferico Francisco R. Almada Km 1, 31410, Chihuahua (Mexico); García-Tenorio, R. [Applied Nuclear Physics Group, University of Seville, ETS Arquitectura, Avda. Reina Mercedes s/n, 41012 Seville (Spain)

    2008-01-01

    Spatial and temporal distribution of the radioisotopes concentrations were determined in sediments near the surface and core samples extracted from two reservoirs located in an arid region close to Chihuahua City, Mexico. At San Marcos reservoir one core was studied, while from Luis L. Leon reservoir one core from the entrance and another one close to the wall were investigated. ²³²Th-series, ²³⁸U-series, ⁴⁰K and ¹³⁷Cs activity concentrations (AC, Bq kg⁻¹) were determined by gamma spectrometry with a high purity Ge detector. ²³⁸U and ²³⁴U ACs were obtained by liquid scintillation and alpha spectrometry with a surface barrier detector. Dating of core sediments was performed applying CRS method to ²¹⁰Pb activities. Results were verified by ¹³⁷Cs AC. Resulting activity concentrations were compared among corresponding surface and core sediments. High ²³⁸U-series AC values were found in sediments from San Marcos reservoir, because this site is located close to the Victorino uranium deposit. Low AC values found in Luis L. Leon reservoir suggest that the uranium present in the source of the Sacramento – Chuviscar Rivers is not transported up to the Conchos River. Activity ratios (AR) ²³⁴U/²³⁸U and ²³⁸U/²²⁶Ra in sediments have values between 0.9–1.2, showing a behavior close to radioactive equilibrium in the entire basin. ²³²Th/²³⁸U, ²²⁸Ra/²²⁶Ra ARs are witnesses of the different geological origin of sediments from San Marcos and Luis L. Leon reservoirs.

  1. Cadmium distribution in sediment and the lugworm Arenicola marina in a low concentration exposure experiment

    Everaarts, J.M.; Devi, K.S.

    /L), which is about 10 times the background concentration of the western Wadden Sea. Two aquaria were used as controls. The experiment lasted 36 days, with intermittent Cd dosing from days 0 to 5 and from days 15 to 25. The animals were not fed during... in the sediment column and the uptake and depuration in the lugworms indicated a dynamic interaction between the animals and their habitat. Evaluation of the present data strongly supported the following mechanisms of Cd distribution through the sediment column...

  2. Radionuclide concentrations in bed sediment and fish tissue within the Rio Grande drainage basin

    In 1992-93, Los Alamos National Laboratory collaborated with the U.S. Geological Survey in an effort to characterize radionuclide concentrations in bed sediment and fish tissue within the Rio Grande drainage basin from Colorado to Texas. Bed sediment was sampled from 18 locations for cesium (137Cs), tritium (3H), strontium (90Sr), plutonium (238Pu and 239Pu), americium (241Am), total uranium (totU) and alpha, beta, and gamma activity. Fish tissue was sampled from 12 locations for 137Cs, 90Sr, 238Pu, 239Pu and totU

  3. Sediment Ksub(d)s and concentration factors for radionuclides in the marine environment

    Both the biological and geochemical processes, which are dependent on the chemical form of the element in question, and the radioactive decay of the nuclide are important parameters in the models used for the calculation of dumping limits for radioactive wastes disposed of in the deep sea. The geochemical processes were not adequately represented in earlier models and only rough approximations of parameters were used in the calculations. This report provides an approach for the calculation of deep-sea sediment distribution coefficients and coastal sediment concentration factors for radionuclides in marine biological materials based, whenever possible, on field data

  4. Radionuclide concentrations in bed sediment and fish tissue within the Rio Grande drainage basin

    Booher, J.L.; Fresquez, P.R.; Carter, L.F.; Gallaher, B.M.; Mullen, M.A.

    1998-02-01

    In 1992-93, Los Alamos National Laboratory collaborated with the U.S. Geological Survey in an effort to characterize radionuclide concentrations in bed sediment and fish tissue within the Rio Grande drainage basin from Colorado to Texas. Bed sediment was sampled from 18 locations for cesium ({sup 137}Cs), tritium ({sup 3}H), strontium ({sup 90}Sr), plutonium ({sup 238}Pu and {sup 239}Pu), americium ({sup 241}Am), total uranium ({sup tot}U) and alpha, beta, and gamma activity. Fish tissue was sampled from 12 locations for {sup 137}Cs, {sup 90}Sr, {sup 238}Pu, {sup 239}Pu and {sup tot}U.

  5. Sediment suspension in oscillatory flow: measurements of instantaneous concentration at high shear

    Staub, Carsten; Jonsson, Ivar G; Svendsen, Ib A.

    1996-01-01

    , resulting in intense sediment transport over a flat bed, The measurements were performed at different levels in a large oscillating water tunnel. They showed some characteristic features of the temporal concentration variation at fixed levels, including a pronounced effect of the orientation of the suction......Different syphon type suspended load probes were used together with a specially developed ''carousel'' sampler for measurements of the instantaneous sediment concentration in turbulent oscillatory flow over a sand bed, Shields parameters were well above the ripple/flat bed transition region...... tube relative to the flow. The variation with height of the average concentration is reasonably well described assuming a constant turbulent diffusivity, and the magnitude of this can be predicted relatively well using simple turbulence arguments. Two empirical formulae for the extrapolated bed...

  6. The attenuation of concentrations model: a new method for assessing mercury mobility in sediments

    Julio C. Wasserman

    2004-02-01

    Full Text Available In this work we propose a new approach for the determination of the mobility of mercury in sediments based on spatial distribution of concentrations. We chose the Tainheiros Cove, located in the Todos os Santos Bay, Brazil, as the study area, for it has a history of mercury contamination due to a chloro-alkali plant that was active during 12 years. Twenty-six surface sediment samples were collected from the area and mercury concentrations were measured by cold vapour atomic absorption spectrophotometry. A contour map was constructed from the results, indicating that mercury accumulated in a "hot spot" where concentrations reach more than 1 µg g-1. The model is able to estimate mobility of mercury in the sediments based on the distances between iso-concentration contours that determines an attenuation of concentrations factor. Values of attenuation ranged between 0.0729 (East of the hot spot, indicating higher mobility to 0.7727 (North of the hot spot, indicating lower mobility.

  7. Partition of organochlorine concentrations among suspended solids, sediments and brown mussel Perna perna, in tropical bays.

    Galvao, Petrus; Henkelmann, Bernhard; Longo, Renan; Dorneles, Paulo Renato; Torres, João Paulo Machado; Malm, Olaf; Schramm, Karl-Werner

    2014-11-01

    For evaluating the brown mussel Perna perna as a sentinel organism regarding environmental concentrations of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs), the present study reports original data on the relationship between the concentrations of these chemicals in bottom surface sediments, suspended solids (SS) and concentrations bioaccumulated by this bivalve. Three P. perna cultivation areas, located at three bays in southeastern Brazil were used in this study. The three estuaries are under different degrees of environmental impact. Variations in the OCP and PCB concentrations bioaccumulated by the bivalves tended to be similar to those observed in the sediment, but differed from those found in SS. This latter difference might suggest that the SS trapping apparatuses should have been left in place for approximately 60 days (not only 15 days). This longer period would allow the integration of the environmental variability of the OCP and PCB burden adsorbed to this compartment. Authors encourage future studies to evaluate P. perna exposure to OCPs and PCBs through the evaluation of sediment concentrations. PMID:25113178

  8. Factors affecting metal concentrations in the upper sediment layer of intertidal reedbeds along the river Scheldt.

    Du Laing, Gijs; Vandecasteele, Bart; De Grauwe, Pieter; Moors, Wouter; Lesage, Els; Meers, Erik; Tack, Filip M G; Verloo, Marc G

    2007-05-01

    Factors that play a role in determining metal accumulation in sediments of 26 intertidal marshes which are mainly vegetated by reed plants (Phragmites australis) were assessed along the Scheldt estuary (Belgium and The Netherlands). In the upper 20 cm sediment layer, several physico-chemical properties (clay, silt and sand content, organic matter, carbonate and chloride content, pH and conductivity) and aqua regia extractable metals (Cd, Cr, Cu, Ni, Pb, Zn) were determined. The sediments were significantly contaminated with trace metals. The Cd concentrations often exceeded the Flemish soil remediation thresholds for nature areas, whereas Cr, Cu and Zn levels indicated moderate contamination. Pb concentrations occasionally were high, whereas Ni concentrations leaned towards background values. Organic matter was the single most important predictor variable for total metal contents in regression models, except for Cr. Additional significant predictor variables were clay or chloride content, depending on the metal. Observed metal concentrations at sites within a range of a few km from specific point-sources of metals (e.g. shipyards, industrial areas with metallurgic activities, affluents, major motorways) were somewhat higher than predicted by the models, whereas they were lower than predicted at sites which are regularly subjected to flooding by water of high salinity. The ratio between observed and predicted concentrations seems to be a valuable tool for the identification of areas which are specifically impacted by point sources. PMID:17492090

  9. Concentrations of petroleum hydrocarbons in sediments and seawater from the Barents and Norwegian Seas 2003-2005

    Boitsov, Stepan; Klungsøyr, Jarle; Jensen, Henning K. B.

    2007-01-01

    During 2003-2005 cruises have been carried out in the Norwegian Sea and the Barents Sea to collect samples of sediments and seawater for analyses of total hydrocarbons (THC) and polyaromatic hydrocarbons (PAH). The report presents the results from these monitoring studies. The THC and PAH concentrations in sediments and water are generally low and no significant anthropogenic influence is apparent. Natural sources contribute to higher concentrations of THC and PAH in sediments ...

  10. Radionuclide and heavy metal concentrations in water, sediments and biota in the vicinity of Cluff mining operations

    Data is presented on the concentrations of U, Ra-226, Pb-210, Th-230, Th, As, Cu, Pb, Mo, Ni and Zn in water, sediments, aquatic macrophytes and fish near a high grade uranium mining facility. Baseline data acquired in 1975 and 1978-79 is compared to post-development environmental monitoring data from 1980 to 1985. Distribution coefficients (KD) for sediment, and transfer coefficients (T.C.) for biota and derived from the water, sediment and biota concentrations

  11. Hysteresis effects in suspended sediment concentration of an allogenic river channel in a very arid environment

    Yu, Guo-An; Disse, Markus; Yu, Yang

    2016-04-01

    Suspended sediment dynamics of the Tarim River, an allogenic and perennial river flowing in a very arid environment in China, are analyzed to examine the hysteresis effects based on data of flow discharge (Q) and suspended sediment concentration (SSC) from two hydrologic gauging stations in the river in the last five decades (1960-2011). Strong hysteresis effects existed in the sediment rating curves of the Tarim River. Under similar flow conditions, the first flood event in a year quite often causes higher suspended sediment concentration (SSC value), and form a rating curve visibly different from later flood processes. The successive flood events often form rating curves gradually from left to right progressively with time on the SSC-Q plot, indicating that higher flow intensity is needed for later flood events to reach the same SSC value of the earlier flood events. Three hysteresis loop forms, i.e., clockwise, anti-clockwise and Figure-eight existed with occurrence frequency of 57%, 27.3% and 15.6% respectively, showing that clockwise loop is the major hysteresis form and sediment load is generally derived from the channel bed. The very weak banks due to composition of quite homogeneous noncohesive particles (fine sand, silt and almost no clay content) often induce bank failure, which complicates suspended sediment dynamics and causes to shape different hysteresis loops. Somehow random but occurrence of bank collapse with higher possibility near the peak and at the falling limb of a flood hydrograph is probably the major reason causing anti-clockwise and figure-eight hysteresis loops.

  12. Two-dimensional depth-averaged model simulation of suspended sediment concentration distribution in a groyne field

    Duan, Jennifer G.; Nanda, S. K.

    2006-08-01

    SummaryRiver-training structures, such as spur dikes, are effective engineered methods used to protect banks and improve aquatic habitat. This paper reports the development and application of a two-dimensional depth-averaged hydrodynamic model to simulate suspended sediment concentration distribution in a groyne field. The governing equations of flow hydrodynamic model are depth-averaged two-dimensional Reynold's averaged momentum equations and continuity equation in which the density of sediment laden-flow varies with the concentration of suspended sediment. The depth-averaged two-dimensional convection and diffusion equation was solved to obtain the depth-averaged suspended sediment concentration. The source term is the difference between suspended sediment entrainment and deposition from bed surface. One laboratory experiment was chosen to verify the simulated flow field around a groyne, and the other to verify the suspended sediment concentration distribution in a meandering channel. Then, the model utility was demonstrated in a field case study focusing on the confluence of the Kankakee and Iroquois Rivers in Illinois, United States, to simulate the distribution of suspended sediment concentration around spur dikes. Results demonstrated that the depth-averaged, two-dimensional model can approximately simulate the flow hydrodynamic field and concentration of suspended sediment. Spur dikes can be used to effectively relocate suspended sediment in alluvial channels.

  13. Arsenic concentrations in Baltic Sea sediments close to chemical munitions dumpsites

    Bełdowski, Jacek; Szubska, Marta; Emelyanov, Emelyan; Garnaga, Galina; Drzewińska, Anna; Bełdowska, Magdalena; Vanninen, Paula; Östin, Anders; Fabisiak, Jacek

    2016-06-01

    In addition to natural sources and land-originated pollution, the Baltic Sea has another anthropogenic source of arsenic in bottom sediments-arsenic-based Chemical Warfare Agents (CWA). To examine the potential usage of arsenic contents results for monitoring the leakage from chemical weapons, sediment samples were collected from officially reported and potential chemical weapon dumpsites located in the Baltic Sea, and total and inorganic arsenic concentrations were analyzed. Results showed an elevated arsenic content in dumpsite areas compared to reference areas. Correlations of arsenic with other metals and organic matter were studied to elucidate any unusual behavior of arsenic in the dumpsites. In the area of the Bornholm Deep, such behavior was observed for inorganic arsenic. It appears that in close vicinity of dumped munitions, the inorganic arsenic concentration of sediments is not correlated with either organic matter content or authigenic minerals formation, as is commonly observed elsewhere. Investigations on CWA concentrations, performed within the CHEMSEA (Chemical Munition Search and Assesment) project, allowed us to compare the results of arsenic concentrations with the occurrence of arsenic-containing CWA.

  14. Experimental Research on Quantitative Inversion Models of Suspended Sediment Concentration Using Remote Sensing Technology

    2007-01-01

    Research on quantitative models of suspended sediment concentration (SSC) using remote sensing technology is very important to understand the scouring and siltation variation in harbors and water channels. Based on laboratory study of the relationship between different suspended sediment concentrations and reflectance spectra measured synchronously, quantitative inversion models of SSC based on single factor, band ratio and sediment parameter were developed, which provides an effective method to retrieve the SSC from satellite images. Results show that the b1 (430-500nm) and b3 (670-735nm) are the optimal wavelengths for the estimation of lower SSC and the b4 (780-835nm) is the optimal wavelength to estimate the higher SSC. Furthermore the band ratio B2/B3 can be used to simulate the variation of lower SSC better and the B4/B1 to estimate the higher SSC accurately. Also the inversion models developed by sediment parameters of higher and lower SSCs can get a relatively higher accuracy than the single factor and band ratio models.

  15. Sediment distribution coefficients and concentration factors for biota in the marine environment

    In 1985 the IAEA published Technical Reports Series No. 247 (TRS 247), Sediment Kds and Concentration Factors for Radionuclides in the Marine Environment, which provided sediment distribution coefficients (Kds) and concentration factor (CF) data for marine biological material that could be used in models simulating the dispersion of radioactive waste that had been disposed of in the sea. TRS 247 described an approach for calculating sediment or water Kds using stable element geochemical data developed by J.M. Bewers, even though the use of field derived data was emphasized whenever possible. Over the years, TRS 247 has proved to be a valuable reference for radioecologists, marine modellers and other scientists involved in assessing the impact of radionuclides in the marine environment. In 2000 the IAEA initiated a revision of TRS 247 to take account of the new sets of data obtained since 1985.The outcome of this work is this report, which contains revised sediment Kds for the open ocean and ocean margins and CFs for marine biota. CFs for deep ocean ferromanganese nodules. In addition, this report contains CFs for a limited number of elements for marine mammals not included in TRS 247. This revision was carried out at three IAEA Consultants Meetings held in Monaco and Vienna between April 2000 and December 2002

  16. Distribution Characteristics, Concentrations, and Sources of Cd and Pb in Laoxiawan Channel Sediments from Zhuzhou, China.

    Chen, Wen-Wen; Zhang, Jian-Xin; Abass, Olusegun-Kazeem; Wen, Xin-Yu; Huang, Huan-Fang; Qu, Cheng-Kai; Qi, Shi-Hua

    2016-06-01

    Twenty sediment cores encompassing surface (0-20 cm) and deeper (50-60 cm) sediment layers were retrieved from the 3000 m-long Laoxiawan Channel, which receives industrial effluents from Zhuzhou City (China). Analytical results showed that cadmium (Cd) concentrations ranged between 115.7-1126.7 and 108.8-2059.3 mg/kg while lead (Pb) values ranged between 234-3000 and 145-4292 mg/kg in the surface and bottom sediments, respectively. The results also indicated that high levels of Cd and Pb were present in the vicinity of the channel mouth and confluence area. Indices for potential ecological risk and geo-accumulation were used to evaluate the environmental effects and intensity of heavy metal pollution over time. High concentrations of Cd and Pb in the bottom sediments of Laoxiawan Channel were mainly associated with wastewater discharge (10(6) m(3)/year). Thus, the Laoxiawan Channel may be an important metal contaminant source for the Xiang River. PMID:27025765

  17. Application of PAH concentration profiles in lake sediments as indicators for smelting activity.

    Warner, Wiebke; Ruppert, Hans; Licha, Tobias

    2016-09-01

    The ability of lake sediment cores to store long-term anthropogenic pollution establishes them as natural archives. In this study, we focus on the influence of copper shale mining and smelting in the Mansfeld area of Germany, using the depth profiles of two sediment cores from Lake Süßer See. The sediment cores provide a detailed chronological deposition history of polycyclic aromatic hydrocarbons (PAHs) and heavy metals in the studied area. Theisen sludge, a fine-grained residue from copper shale smelting, reaches the lake via deflation by wind or through riverine input; it is assumed to be the main source of pollution. To achieve the comparability of absolute contaminant concentrations, we calculated the influx of contaminants based on the sedimentation rate. Compared to the natural background concentrations, PAHs are significantly more enriched than heavy metals. They are therefore more sensitive and selective for source apportionment. We suggest two diagnostic ratios of PAHs to distinguish between Theisen sludge and its leachate: the ratio fluoranthene to pyrene ~2 and the ratio of PAH with logKOW5.7 converging to an even lower value than 2.3 (the characteristic of Theisen sludge) to identify the particulate input in lake environments. PMID:27176930

  18. Toxicity Assessment of Sediments with Natural Anomalous Concentrations in Heavy Metals by the Use of Bioassay

    Francisco Martín

    2010-01-01

    Full Text Available The potential toxicity in riverbed sediments was assessed with a bioassay using the bioluminescent bacteria Vibrio fischeri. The selected area was characterized by the presence of ultramafic rocks (peridotites, and the sediments had high values in Ni, Cr, and Co. For the toxicity bioassay with Vibrio fischeri, water-soluble forms were used. The results indicated that most of the samples had a very low degree of toxicity, with 10% of reduction in luminescence in relation to the control; meanwhile 25% of the samples had a moderate degree of toxicity with a reduction in luminescence between 13 and 21% in relation to the control. The toxicity index correlated significantly with the concentrations of Ni and Cr in the water extracts. This toxicity bioassay was proved to be a sensitive and useful tool to detect potential toxicity in solutions, even with anomalous concentrations in heavy metals of natural origin.

  19. Radionuclide concentrations in a recent McNary Dam sediment core

    On February 2, 1971, a bed sediment core sample was obtained from behind McNary Dam for radioanalysis. This sample was obtained by Environmental Evaluations after learning, in late 1970, that the Radiological Sciences Department had terminated their core sampling programs. Since occasional core sampling was considered to be a useful adjunct to the environmental evaluation program, the fine-sediment corer was borrowed from Radiological Sciences, and two cores were obtained, one of which was analyzed by the Technical Analysis Section. Concentrations of 46Sc, 54Mn, 60Co, 65Zn, 152Eu, 154Eu, and 155Eu, the only radionuclides for which analyses were requested, are plotted as a function of depth. Concentrations of 46Sc, 60Co, and 65Zn found in an October 1965 core are plotted for comparison. An interesting similarity exists between these two sets of data obtained more than five years apart. 1 ref., 5 figs

  20. Reducing sediment concentration and soil loss using organic and inorganic amendments at plot scale

    S. H. R. Sadeghi; L. Gholami; Homaee, M.; A. Khaledi Darvishan

    2015-01-01

    Various organic and inorganic mulches are used for soil conservation purposes, the effectiveness of which on soil characteristics has not been comprehensively considered from different aspects. The present study surveys the efficiency of straw mulch, manure and TA-200 polyacrylamide with respective rates of 500, 300 and 50 g m−2 in changing sediment concentration and soil loss. The experiments were conducted for sandy-loam soil taken from a summer rangeland, the ...

  1. Reducing sediment concentration and soil loss using organic and inorganic amendments at plot scale

    S. H. R. Sadeghi; L. Gholami; M. Homaee; A. Khaledi Darvishan

    2015-01-01

    Although various organic and inorganic mulches are used for soil conservation purposes, the comparative effectiveness of them on soil characteristics has not been comprehensively considered from different aspects. The present study is therefore an attempt to determine the efficiency of straw mulch, manure and TA-200 polyacrylamide with respective rates of 500, 300 and 50 g m-2, respectively, in changing sediment concentration and soil loss. The experiments were conduc...

  2. Investigating sampling accuracy to estimate sediment concentrations in erosion plot tanks

    NIKKAMI, Davood

    2012-01-01

    Significant errors when sampling from collection tanks installed at the lower end of soil erosion plots may lead researchers toward wrong conclusions. Limited research has been found on sampling accuracy. In this study, a cylindrical sampler is introduced as a new sampling device and its sampling accuracy is investigated and compared with 2 other manual methods, namely bottle and pipette. Three target sediment concentrations were prepared in separate 213.5-L collection tanks as 3 replications...

  3. Estimating suspended sediment concentrations using a broadband ADCP in Mahshahr tidal channel

    P. Ghaffari

    2011-07-01

    Full Text Available Data sets of Acoustic Doppler Current Profiler (ADCP backscatter intensities (ABS were used to evaluate suspended sediment concentrations (SSC in the Mahshahr Channel (MC of the Persian Gulf. Since the echo intensity is closely related to turbidity in water, the ADCP may be a promising tool to monitor the sediment transport. The low susceptibility of the acoustic backscatter to bio-fouling and the ADCP provision of current profiles as well as sediment time series makes this monitoring method more advantageous compared with the traditional methods. Time series of ADCP backscatter intensity profiles were used for improving temporal resolution of SSC estimates. Backscatter and traditional observational data were separated into two segments. The first part was utilized for calibrating the backscatter data and attributing the intensity to suspended particle concentrations and using the second part acoustic intensities were validated. Acoustic based SSC estimates are slightly underestimated in comparison with traditional water sample based SSC values, but still there is good agreement between acoustic SSC and traditional observations. Results illustrate a rather high correlation between lab based and acoustic based particles in suspension (R2 = 88 %. Additionally measurements reveal the domination of a semidiurnal ebb asymmetric system in the MC. Tidal currents provide the main energy source for particle resuspension and transport. Maximum suspended load concentrations are evident in ebb tides, while the currents strengths are enough to refloat loads from the bed. In general spring tides show higher SSC values compared with neap tides in the study area.

  4. NORM activity concentration in sediment cores from the Peninsular Malaysia East Coast Exclusive Economic Zone

    Study for distribution of Naturally Occurring Radioactive Materials (NORM) i.e. 226Ra, 228Ra and 40K in the east coast of Peninsular Malaysia Exclusive Economic Zone (EEZ) was carried out as part of the national marine environment project. Sixteen marine sediment cores from selected locations within the EEZ were collected for determination of NORM activity concentrations using high-purity germanium (HPGe) gamma spectrometer. From the measurement, the activity concentration of 226Ra, 228Ra and 40K is ranged from 16 ± 4 Bq/kg to 46 ± 6 Bq/kg (total mean 30), 28 ± 7 Bq/kg to 87 ± 11 Bq/kg (total mean 56) and 171 ± 33 Bq/kg to 690 ± 89 Bq/kg (total mean 420), dry wt., respectively. The activity concentrations of radionuclides in most of the core were quite uniform suggesting that there were thorough vertical mixed of sediment throughout the core. The results obtained were also in good agreement with those previous reported from other countries in the region and therefore can be used to enhance present radioactivity database. The calculated external hazard values were ranged from 0.25 to 0.51 with the mean of 0.38 (less than unity) showed little risk of external hazard to the workers handling the sediments and it was likely low level of the mainland natural gamma-radiation in the east coast of Peninsular Malaysia. (author)

  5. Heavy Metal Concentration in the Surface Sediment of Tanjung Lumpur Mangrove Forest, Kuantan, Malaysia

    Surface sediment samples from 2 transect (20 sampling points) of Tanjung Lumpur mangrove forest were analyzed for the concentrations of Pb, Cu, Co and Mn. In this study, the average concentrations of Pb, Cu, Co and Mn were 44.41 μg/g dry weight, 32.79 μg/g dry weight, 5.79 μg/g dry weight and 117.73 μg/g dry weight, respectively. The calculated enrichment factors (EF) obtained for Co and Mn can be considered to have the terigeneous in sources while Pb and Cu are considered to have anthropogenic input. (author)

  6. Organic carbon concentration profiles in recent cave sediments: records of agricultural pollution or diagenesis?

    Bottrell, S H

    1996-01-01

    Recent (<7 years old) cave sediments in Speedwell Cavern, Derbyshire, show an approximately exponential decay of organic carbon with depth. This phenomenon was thought to be due to one of two causes: (i) changing agricultural practice within the catchment feeding the cave, especially the increased use of sewage sludge and animal slurry as fertilizer; (ii) a relatively constant organic carbon concentration over time in the input sediment, with subsequent carbon mineralization during diagenesis. Carbon isotope composition of the organic material and the evolution of H/C ratio with depth indicate that the latter hypothesis is correct and that the profiles result from microbial diagenesis, not increased organic carbon inputs. By comparison with sediment of known (7 years) age, temporal decay constants for organic matter can be derived; these lie between rates previously determined for organic matter decomposition in marine sediments and soils. The H/C ratio of organic matter can be modelled as a function of time and proceeds in a similar fashion to soil organic material. PMID:15091425

  7. Parameterization of Time-Averaged Suspended Sediment Concentration in the Nearshore

    Hyun-Doug Yoon

    2015-11-01

    Full Text Available To quantify the effect of wave breaking turbulence on sediment transport in the nearshore, the vertical distribution of time-averaged suspended sediment concentration (SSC in the surf zone was parameterized in terms of the turbulent kinetic energy (TKE at different cross-shore locations, including the bar crest, bar trough, and inner surf zone. Using data from a large-scale laboratory experiment, a simple relationship was developed between the time-averaged SSC and the time-averaged TKE. The vertical variation of the time-averaged SSC was fitted to an equation analogous to the turbulent dissipation rate term. At the bar crest, the proposed equation was slightly modified to incorporate the effect of near-bed sediment processes and yielded reasonable agreement. This parameterization yielded the best agreement at the bar trough, with a coefficient of determination R2 ≥ 0.72 above the bottom boundary layer. The time-averaged SSC in the inner surf zone showed good agreement near the bed but poor agreement near the water surface, suggesting that there is a different sedimentation mechanism that controls the SSC in the inner surf zone.

  8. Determination of naturally occurring uranium concentrations in seawater, sediment, and marine organisms in Japanese estuarine areas

    For safety assessments of geological repositories of nuclear waste, understanding of uranium (U) fate in estuarine areas is important because U chemical behavior in the areas is expected to be complex. Environmental transfer parameters such as sediment-water distribution coefficients (Kd) and concentration ratios (CRs) for marine organisms are useful in mathematical models for the assessment. However, due to its low concentration in estuarine water, Kd and CF data for U are scarce. Thus we studied a rapid method for separation and concentration of U from estuarine water samples using NOBIAS-CHELATE PA1 resin columns followed by inductively coupled plasma mass spectrometry (ICP-MS) for U measurement. Chemical recovery was about 100% at pH of 5.7 ± 0.1 from the water samples and alkali and alkaline earth metals were removed. The method was used to measure U concentrations in estuarine water samples collected at eight Japanese estuarine areas; they ranged from 0.1 to 3.8 μg L-1. We also measured U concentrations in sediment and marine organism samples by ICP-MS after acid digestion. Using these values, we observed K d (range: 39-284 L kg-1) and CRs (0.86-52 L kg-1 for macroalgae, 0.087-15 L kg-1 for crustaceans, and 0.52-93 L kg-1 for molluscs). (author)

  9. Experimental Study on Suspended Sediment Concentration and Its Vertical Distribution under Spilling Breaking Wave Actions in Silty Coast

    XIA Yun-feng; XU Hua; CHEN Zhong; WU Dao-wen; ZHANG Shi-zhao

    2011-01-01

    In this paper,flume experiments are focused on sediment transport inside and outside the surf zone.According to the energy dissipation balance principle of sediment-laden flow and the similarity between energy dissipation of spilling breaking wave and hydraulic jump,formulas are proposed to predict time averaged suspended sediment concentration under both non-breaking and breaking waves.Assuming that the sediment diffusion coefficient,which is related with energy dissipation,is proportional to water depth,formulas are proposed to predict close-to-bed suspended sediment concentration and vertical distribution of suspended sediment under spilling breaking waves,and the prediction shows a good agreement with the measurement.

  10. A randomized, double-blind, placebo-controlled trial of calcium acetate on serum phosphorus concentrations in patients with advanced non-dialysis-dependent chronic kidney disease

    Ho Chiang-Hong

    2011-02-01

    Full Text Available Abstract Background Hyperphosphatemia in patients with chronic kidney disease (CKD contributes to secondary hyperparathyroidism, soft tissue calcification, and increased mortality risk. This trial was conducted to examine the efficacy and safety of calcium acetate in controlling serum phosphorus in pre-dialysis patients with CKD. Methods In this randomized, double-blind, placebo-controlled trial, 110 nondialyzed patients from 34 sites with estimated GFR 2 and serum phosphorus > 4.5 mg/dL were randomized to calcium acetate or placebo for 12 weeks. The dose of study drugs was titrated to achieve target serum phosphorus of 2.7-4.5 mg/dL. Serum phosphorus, calcium, iPTH, bicarbonate and serum albumin were measured at baseline and every 2 weeks for the 12 week study period. The primary efficacy endpoint was serum phosphorus at 12 weeks. Secondary endpoints were to measure serum calcium and intact parathyroid hormone (iPTH levels. Results At 12 weeks, serum phosphorus concentration was significantly lower in the calcium acetate group compared to the placebo group (4.4 ± 1.2 mg/dL vs. 5.1 ± 1.4 mg/dL; p = 0.04. The albumin-adjusted serum calcium concentration was significantly higher (9.5 ± 0.8 vs. 8.8 ± 0.8; p p Conclusions In CKD patients not yet on dialysis, calcium acetate was effective in reducing serum phosphorus and iPTH over a 12 week period. Trial Registration www.clinicaltrials.gov NCT00211978.

  11. Controls on Suspended Sediment Concentrations and Turbidity within a Reforested, Southern Appalachian Headwater Basin

    Jerry R. Miller

    2015-06-01

    Full Text Available Water quality data collected between 2007 and 2014 within the Allen Creek Watershed were used to: (1 determine the factors controlling the temporal variations in turbidity and suspended sediment concentration (SSC within a representative, high-gradient headwater basin in the Southern Appalachians; and (2 assess the recovery of water quality following extensive logging operations during the early to mid-1900s. Regression analysis suggests that suspended sediment is primarily derived from upland areas and variations in concentration reflect rainfall intensity and total event precipitation. Overall, SSC and turbidity were low in stream waters in comparison to both reference values for stable streams and more developed basins in the region. Some floods were characterized by high SSC values, but limited turbidity and vice versa. Differences in measured SSC and turbidity between storms reflect different controls on the two parameters, and the apparent influence of natural organic matter on turbidity during rainfall events that are incapable of transporting sediment to the channel via overland flow. Low SSC and turbidity values are presumably related to the reforestation of hillslopes and riparian buffers following the cessation of logging operations. They also are due to a historical reduction in the sedimentological connectivity of hillslopes and tributaries with the axial channel that occurred during logging operations.

  12. Improved Method for the Quantification of Methane Concentrations in Unconsolidated Lake Sediments.

    Tyroller, Lina; Tomonaga, Yama; Brennwald, Matthias S; Ndayisaba, Cyprien; Naeher, Sebastian; Schubert, Carsten; North, Ryan P; Kipfer, Rolf

    2016-07-01

    There is conclusive evidence that the methods most commonly used to sample methane (CH4) dissolved in the pore water of lake sediments produce results that are likely to be affected by gas loss or gas exchange with the atmosphere. To determine the in situ amount of CH4 per unit mass of pore water in sediments, we developed and validated a new method that combines techniques developed for noble-gas analysis in pore waters with a standard headspace technique to quantify the CH4 present in the pore space in dissolved and gaseous form. The method was tested at two sites: Lake Lungern, where CH4 concentrations were close to saturation; and Lake Rotsee, where CH4 concentrations are known to exceed saturation and where CH4 bubble formation and gas ebullition are commonly observed. We demonstrate that the new method, in contrast to the available methods, more reliably captures the total amount of CH4 per unit mass of pore water consisting of both dissolved and free CH4 (i.e., gas bubbles) in the pore space of the sediment. PMID:27244276

  13. A Stochastic Framework For Sediment Concentration Estimation By Accounting Random Arrival Processes Of Incoming Particles Into Receiving Waters

    Tsai, C.; Hung, R. J.

    2015-12-01

    This study attempts to apply queueing theory to develop a stochastic framework that could account for the random-sized batch arrivals of incoming sediment particles into receiving waters. Sediment particles, control volume, mechanics of sediment transport (such as mechanics of suspension, deposition and resuspension) are treated as the customers, service facility and the server respectively in queueing theory. In the framework, the stochastic diffusion particle tracking model (SD-PTM) and resuspension of particles are included to simulate the random transport trajectories of suspended particles. The most distinguished characteristic of queueing theory is that customers come to the service facility in a random manner. In analogy to sediment transport, this characteristic is adopted to model the random-sized batch arrival process of sediment particles including the random occurrences and random magnitude of incoming sediment particles. The random occurrences of arrivals are simulated by Poisson process while the number of sediment particles in each arrival can be simulated by a binominal distribution. Simulations of random arrivals and random magnitude are proposed individually to compare with the random-sized batch arrival simulations. Simulation results are a probabilistic description for discrete sediment transport through ensemble statistics (i.e. ensemble means and ensemble variances) of sediment concentrations and transport rates. Results reveal the different mechanisms of incoming particles will result in differences in the ensemble variances of concentrations and transport rates under the same mean incoming rate of sediment particles.

  14. Method for relating suspended-chemical concentrations to suspended-sediment particle-size classes in storm-water runoff

    Rinella, Joseph F.; McKenzie, Stuart W.

    1982-01-01

    A method has been developed to relate suspended-chemical concentrations (associated with suspended sediments) in storm-water runoff to suspended-sediment particle-size classes. These classes are based on settling velocities in quiescent native water. This method requires processing 20 liters of water having a suspended-sediment concentration greater than 500 milligrams per liter. However, samples with suspended-sediment concentrations as low as 250 milligrams per liter may be analyzed, if sample volumes are increased to 50 liters. The time required for one person to separate suspended sediments into particle-size classes ranges from 6 to 14 hours. This report outlines procedures for processing metal, nutrient, and organic samples.

  15. Heavy metal concentrations in litteral sediments from the Beagle Channel, Tierra del Fuego, Argentina.

    Amin, O; Ferrer, L; Marcovecchio, J

    1996-07-01

    For the first time the concentration of trace metals (Fe, Pb, Cu, Zn, Cd and total Hg) of sediments from the coastal zone of the Beagle Channel (Tierra del Fuego, in Southern Argentina) were measured. Atomic absorption spectrophotometry was utilized in order to determine the metal contents. The level of metals as observed in the sediments was recognized as the natural background, even though the use of normalization of lead, copper, and zinc to iron allowed the identification of the main sources of metal pollution for this environment. In order to develop future environmental monitoring programmes for the area of Ushuaia city and the Beagle Channel, the present results need to be considered. PMID:24193396

  16. Follicular dynamics, estradiol-17[beta] concentrations, and luteinizing hormone release following norgestomet implant insertion during estrus synchronization with melengestrol acetate

    Faber, Eric G.

    1995-01-01

    The objective of this experiment was to determine whether norgestomet implant insertion following melengestrol acetate (MGA) administration altered LH pulse frequency and follicular dynamics. Multiparous Angus cows were randomly assigned to receive MGA (.5 mg*cow-l*d-l ; MGA; n = 14) for 18 d or to receive MGA (.5 mg*cow·-l l*d-l; MGA-N; n = 11) for 15 d and a norgestomet implant for 4 d beginning on d 15. Ultrasound was used to record images of each ovary in cows beginning on...

  17. Trace metal concentrations and their transfer from sediment to leaves of four common aquatic macrophytes.

    Łojko, Renata; Polechońska, Ludmiła; Klink, Agnieszka; Kosiba, Piotr

    2015-10-01

    In the present study, the concentrations of trace and alkali metals in leaves of four common helophytes, Sparganium erectum, Glyceria maxima, Phalaris arundinacea, and Phragmites australis, as well as in corresponding water and bottom sediments were investigated to ascertain plant bioaccumulation ability. Results showed that Mn and Fe were the most abundant trace metals in all plant species, while Co and Pb contents were the lowest. Leaves of species studied differed significantly in respect of element concentrations. The highest concentrations of Mg, Na, Fe, Mn, Cu, Pb, and Ni were noted in S. erectum while the highest contents of Co, Ca, Zn, and Cr in Phalaris arundinacea. Phragmites australis contained the lowest amounts of most elements. Concentrations of Co, Cr, Fe, and Mn in all species studied and Ni in all except for Phragmites australis were higher than natural for hydrophytes. The leaves/sediment ratio was more than unity for all alkali metals as well as for Cu and Mn in Phragmites australis; Cr, Co, and Zn in Phalaris arundinacea; Cr and Mn in S. erectum; and Cr in G. maxima. High enrichment factors and high levels of toxic metals in the species studied indicated a special ability of these plants to absorb and store certain non-essential metals and, consequently, their potential for phytoremediation of contaminated aquatic ecosystems. PMID:26004561

  18. Climate-induced fluctuations of 10Be concentration in Lake Baikal sediments

    Sedimentary 10Be records covering the last 150 kyr were obtained from three cores collected at the Academician Ridge (BDP-96/hole2 core and VER96/st.3 core) and at the Buguldeika Saddle (BDP-93/hole2 core) in Lake Baikal. The 10Be concentrations of the three cores varied between 0.5x109 and 1.5x109 atoms/g, and coincidently dropped at the stratigraphic intervals of marine oxygen isotope stages (MIS) 2, 4, 5d and 6. The depositional fluxes of 10Be, on the other hand, generally rose in those stages having an increase in the dry bulk densities and sediment accumulation rates. These results are consistent with previous work (Horiuchi et al., 1999), suggesting that the dilution effects of low-10Be-concentration particles principally controlled the fluctuations of the 10Be concentrations of Lake Baikal sediments. Low-10Be-concentration particles have been intensively produced by mechanical weathering and physical erosion under the cold and dry climatic conditions during the peak glaciation period, and have been directly brought from the source areas into the lake as a result of the thin vegetative cover of the watershed

  19. The effects of sediment depth and oxygen concentration on the use of organic matter: An experimental study using an infiltration sediment tank.

    Freixa, A; Rubol, S; Carles-Brangarí, A; Fernàndez-Garcia, D; Butturini, A; Sanchez-Vila, X; Romaní, A M

    2016-01-01

    Water flowing through hyporheic river sediments or artificial recharge facilities promotes the development of microbial communities with sediment depth. We performed an 83-day mesocosm infiltration experiment, to study how microbial functions (e.g., extracellular enzyme activities and carbon substrate utilization) are affected by sediment depth (up to 50 cm) and different oxygen concentrations. Results indicated that surface sediment layers were mainly colonized by microorganisms capable of using a wide range of substrates (although they preferred to degrade carbon polymeric compounds, as indicated by the higher β-glucosidase activity). In contrast, at a depth of 50 cm, the microbial community became specialized in using fewer carbon substrates, showing decreased functional richness and diversity. At this depth, microorganisms picked nitrogenous compounds, including amino acids and carboxyl acids. After the 83-day experiment, the sediment at the bottom of the tank became anoxic, inhibiting phosphatase activity. Coexistence of aerobic and anaerobic communities, promoted by greater physicochemical heterogeneity, was also observed in deeper sediments. The presence of specific metabolic fingerprints under oxic and anoxic conditions indicated that the microbial community was adapted to use organic matter under different oxygen conditions. Overall the heterogeneity of oxygen concentrations with depth and in time would influence organic matter metabolism in the sediment tank. PMID:25900223

  20. Dilution of riverine heavy metal input concentrations by suspension of sediments and algal growth in the IJsselmeer.

    Winkels, H.J.; Blom, G.; Kroonenberg, S.B.; Lijklema, L.

    1998-01-01

    This study evaluates the effects of sediment erosion and primary production on the temporal and spatial variability of heavy metals concentration in settling solids in the lakes IJsselmeer and Ketelmeer. Settling solids were sampled fortnightly using sediment traps at two sites in the IJsselmeer and

  1. Distinguishing between natural and aquaculture-derived sediment concentrations of heavy metals in the Broughton Archipelago, British Columbia

    Marine sediment samples were collected in the Broughton Archipelago, British Columbia, to assess the use of a geochemical normalization technique in the identification of a chemical tracer of aquaculture waste material. Zinc and copper were suggested as tracers of feed pellets, while copper was considered an indicator of anti-foulant agents used on netpen systems. The sediment samples were analyzed for carbon, nitrogen, organic matter, water, trace-element, and free sulfide concentrations, and sediment grain-size distribution. Sediment texture analysis revealed a wide range of substrate types from sand to silty loam categories. Strong relationships between sediment texture, sediment porosity, and organic content were observed across both near-field and far-field stations. Excess zinc and copper sediment concentrations, identified using a lithium-normalization technique, were restricted to near-field sampling stations (0 and 30 m from netpen systems). The relationships between these metal tracers and organic content and sulfur concentrations were explored to account for variations in sediment concentrations of zinc and copper

  2. Sediment concentration profiles in bed-near-bed layers under unsteady flow and sediment conditions : a CT-Scanned flume investigation

    Leclair, Suzanne; Long, Bernard

    2015-04-01

    This paper presents a case study from a CT-scan flume experiment on the variation in sediment transport (concentration) under transitional, initially high-regime (but decreasing), sub-critical flow with bed erosion or no net aggradation. The objective is to better understand sediment transport during unsteady flows such as during a wining flood. In particular, the effect of mud-aggregate transport on sediment concentration in the bed-near-bed continuum was addressed. CT-scans were taken during sediment transport, with plane beds or dunes being the bed state. The density material (water and/or sediment) in over 105 volumes (voxels, each approximately equivalent to a grain of 0.8 mm) were analysed. Computed Tomography technology provides high-resolution results, both in time and space, and allows recognition of subtle changes in the shape of relative sediment concentration profile with bed states. The migration and attrition of mud aggregates in this experiment increased the mean volume fraction sediment concentration in the bed-near-bed layer (lower 5% of the flow) by a factor of about 2, from an inital value of 0.12 up to 0.25, and back to 0.13 when the supply ended. Also, the presence of mud-aggregates in the preserved deposits (transported as bedload) increases bed porosity. This case study demonstrates the great potential of Computed Tomography in process-oriented, experimental sedimentology. The community would benefit from more collaborative research using this technology, including data sharing as suggested by initiatives such as the Sediment Experimentalists Network (http://workspace.earthcube.org/sen)

  3. Concentration ratios for small mammals collected from the exposed sediments of a 137Cs contaminated reservoir

    137Cs concentration ratios were computed for small mammals collected from the dried sediments of a partially drained, contaminated reservoir. Soil 137Cs activity concentrations were heterogeneous on small and large spatial scales and had a geometric mean of 253 (range 23-2110) Bq/kg dry weight. Mean 137Cs activity concentrations in composite cotton rat Sigmodon hispidus and cotton mouse Peromyscus gossypinus samples averaged 2480 (range 556-6670) and 471 (range 96-1000) Bq/kg whole body dry weight, respectively. About 50% of the variance in cotton rat tissue 137Cs activity was explained by variation in soil 137Cs activity. Soil-to-animal dry weight concentration ratios averaged 6.0 for cotton rats and 1.2 for cotton mice and were generally similar to 137Cs concentration ratios for herbivorous, homeothermic animals from other contaminated ecosystems. In the RESRAD-BIOTA dose model, the default wet-weight concentration ratio for 137Cs in terrestrial animals is 110 resulting in an estimate of internal and external radiation doses to terrestrial biota that is 44 times more than the dose calculated with the actual measured wet-weight concentration ratio for cotton rats (1.6). These results show that site-specific concentration ratios can significantly affect the estimation of dose

  4. A report on the trace element concentrations in sediments, vegetation, and fishes from the Lake Thompson Wetland Complex, South Dakota

    US Fish and Wildlife Service, Department of the Interior — The results of this study identify the contaminants present, if any, and their concentrations in fish, cattail roots, and sediments from areas of concern in the...

  5. Suspended sediment concentration and optical property observations of mixed-turbidity, coastal waters through multispectral ocean color inversion

    Multispectral satellite ocean color data from high-turbidity areas of the coastal ocean contain information about the surface concentrations and optical properties of suspended sediments and colored dissolved organic matter (CDOM). Empirical and semi-analytical inversion algorit...

  6. Reducing sediment concentration and soil loss using organic and inorganic amendments at plot scale

    S. H. R. Sadeghi

    2015-01-01

    Full Text Available Although various organic and inorganic mulches are used for soil conservation purposes, the comparative effectiveness of them on soil characteristics has not been comprehensively considered from different aspects. The present study is therefore an attempt to determine the efficiency of straw mulch, manure and TA-200 polyacrylamide with respective rates of 500, 300 and 50 g m-2, respectively, in changing sediment concentration and soil loss. The experiments were conducted for sandy-loam soil (collected from the top 0–20 cm-layer taken from a summer rangeland, the Alborz Mountains, Northern Iran under laboratory conditions with simulated rainfall intensities of 30, 50, 70 and 90 mm h-1 and the slope of 30%. The results showed that the straw mulch decreased soil concentration at rate of 45.60% compared to the control plots, and performed better than manure (8.98% reduction and PAM (4.74% reduction. The results showed that the maximum reduction in sediment concentration and soil loss for all soil amendments occurred in the rainfall intensity of 90 mm h-1 with the rates of 58.69 and 63.24%, for straw mulch, 14.65 and 13.14%, for manure and 20.15 and 23.44% for TA-200, respectively.

  7. Study of metal concentration in sediment of some springs of Lebanon

    Full text.Surficial sediment samples were collected from seventeen springs distributed all over Lebanon (east, west, north and south). Concentrations of metals Ca, Fe, Mn, Ni, Cu, Cr, Zn and Pb were determined by energy dispersive x-ray fluorescence technique. Irradiation was done by the radioisotope source Cd-109 and the detection by an EG and G Si(Li) detector. These analysis was done in attempt to assess the impact of anthropogenic sources on ground water quality. Metals concentration in sediment were found to be (Ca:0.05-47%, Fe:0.24-4.2%, Cr:< dl-641 mg/Kg, Zn:< dl-268 mg/Kg, Ni:< dl-96 mg/Kg, Mn:< dl-1356 mg/Kg, Pb:6.6-79 mg/Kg dry weight). Elevated levels of Fe and Mn were found in some sites and of Zn, Ni and Cr in other sites in comparison with other areas of the world were attributed to anthropogenic inputs. Lead concentrations obtained in this study were of the same order of magnitude as those obtained from other regions of the world including come polluted ones due to influence arising out of gasoline combustion related activities

  8. Metal toxicity in a sediment-dwelling polychaete: Threshold body concentrations or overwhelming accumulation rates?

    Carmen Casado-Martinez, M., E-mail: c.casado-martinez@nhm.ac.u [Department of Zoology, The Natural History Museum, Cromwell Road, London SW7 5BD (United Kingdom); Smith, Brian D. [Department of Zoology, Natural History Museum, Cromwell Road, London SW7 5BD (United Kingdom); Luoma, Samuel N. [John Muir Institute of the Environment, University of California at Davis, Davis, CA 95616 (United States); Rainbow, Philip S. [Department of Zoology, Natural History Museum, Cromwell Road, London SW7 5BD (United Kingdom)

    2010-10-15

    We followed the net accumulation of As, Cu and Zn in the deposit-feeding polychaete Arenicola marina exposed in the laboratory to natural metal-contaminated sediments, one exposure leading to mass mortality between day 10 and 20, and the other not causing lethality over a period of 60 days of exposure. The worms showed lower total accumulated metal concentrations just before mortality occurred (<20 days) at the lethal exposure, than after 30 days of exposure to sediments not causing mortality. Moreover rates of accumulation of As, Cu and Zn were significantly higher in the lethal exposure than in the sublethal exposure. Our results show that it is not possible to link mortality to a critical total body concentration, and we add to a growing body of literature indicating that metal toxicity occurs when organisms cannot cope with overwhelming influx and subsequent accumulation rates. - Laboratory exposures with the deposit-feeding polychaete Arenicola marina suggest that toxicity is not caused by the accumulated concentration of toxic metals in the body of the animal, but by the rate at which the toxic metal is accumulated.

  9. Metal toxicity in a sediment-dwelling polychaete: Threshold body concentrations or overwhelming accumulation rates?

    We followed the net accumulation of As, Cu and Zn in the deposit-feeding polychaete Arenicola marina exposed in the laboratory to natural metal-contaminated sediments, one exposure leading to mass mortality between day 10 and 20, and the other not causing lethality over a period of 60 days of exposure. The worms showed lower total accumulated metal concentrations just before mortality occurred (<20 days) at the lethal exposure, than after 30 days of exposure to sediments not causing mortality. Moreover rates of accumulation of As, Cu and Zn were significantly higher in the lethal exposure than in the sublethal exposure. Our results show that it is not possible to link mortality to a critical total body concentration, and we add to a growing body of literature indicating that metal toxicity occurs when organisms cannot cope with overwhelming influx and subsequent accumulation rates. - Laboratory exposures with the deposit-feeding polychaete Arenicola marina suggest that toxicity is not caused by the accumulated concentration of toxic metals in the body of the animal, but by the rate at which the toxic metal is accumulated.

  10. Ratios of total suspended solids to suspended sediment concentrations by particle size

    Selbig, W.R.; Bannerman, R.T.

    2011-01-01

    Wet-sieving sand-sized particles from a whole storm-water sample before splitting the sample into laboratory-prepared containers can reduce bias and improve the precision of suspended-sediment concentrations (SSC). Wet-sieving, however, may alter concentrations of total suspended solids (TSS) because the analytical method used to determine TSS may not have included the sediment retained on the sieves. Measuring TSS is still commonly used by environmental managers as a regulatory metric for solids in storm water. For this reason, a new method of correlating concentrations of TSS and SSC by particle size was used to develop a series of correction factors for SSC as a means to estimate TSS. In general, differences between TSS and SSC increased with greater particle size and higher sand content. Median correction factors to SSC ranged from 0.29 for particles larger than 500m to 0.85 for particles measuring from 32 to 63m. Great variability was observed in each fraction-a result of varying amounts of organic matter in the samples. Wide variability in organic content could reduce the transferability of the correction factors. ?? 2011 American Society of Civil Engineers.

  11. Evaluation of formalin-acetone sedimentation in the concentration of stool for intestinal parasites.

    Parija, S C; Bhattacharya, S; Padhan, P; Shivaprakash, M R

    2003-07-01

    Formalin-acetone sedimentation was compared with the formalin-ether method for the concentration of stool for intestinal parasites. Of 80 stool specimens, 45 (56.25%) were positive for parasites by the formalin-acetone method. The figures for the two methods were formalin-ether 35 (43.75%) and for the direct lacto-phenol cotton blue wet mount method 17 (21.25%). There was no statistically significant difference in the parasite recovery rate between the two methods. Acetone is more stable, safer, and a cheaper fat solvent and promises to be a useful alternative to ether. PMID:12870605

  12. Delineating suspended sediment concentration patterns in surface waters of the Changjiang Estuary by remote sensing analysis

    LI Jing; GAO Shu; WANG Yaping

    2010-01-01

    Three Landsat TM imageries (taken on 18 May 1987,4 August 1998 and 28 July 2007) were used as the data source to identify the spatial and temporal variations of the suspended sediment concentration (SSC) in surface waters of the Changjiang Estuary.Atmospheric correction was carried out to determine the water-leaving reflectance using the FLAASH module.A regression equation between surveyed SSC and suspended sediment index was chosen to retrieve the SSC from the Landsat TM images.In addition,tidal harmonic analysis was performed to calculate tidal conditions corresponding to the acquisition time of satellite images.The results show that the SSC spatial patterns are similar to the in situ observation results,which show the highest SSC in the region of turbidity maximum zone in the Changjiang Estuary.For the period of 1987 to 2007,the SSC pattern is controlled mainly by tidal dynamic conditions and wind speeds,rather than sediment discharges from the river.

  13. Heavy metals concentration in water and sediments of the Prut River lower sector

    Matache M. L.

    2013-04-01

    Full Text Available A 120 km sector of the Prut River, Eastern Romania, was surveyed for the concentration of four heavy metals (Cd, Cu, Pb and Zn in water and sediments samples. The analysed sector is located on the border between Romania and Moldova and it is part of the Lower Prut Floodplain Natural Park. The most important steel-producing factory in Romania is located in the park vicinity. Four campaigns have been performed for water collection during different river regimes (both flooding and drought. The water quality is an essential condition for the wetland ecosystems within the park area and the aquatic biota they support, as trace elements bioaccumulation along the food webs might appear (David et al., 2012. Sediments can provide useful information regarding mid- and long-term pollution of the aquatic bodies, being capable of sequestering and releasing important amounts of heavy metals depending on the river regime and extreme situations (van Gestel, 2008; Verhoeven, 2009. For the sediments samples, there is an ascendant trend from upstream to the junction with the Danube River, as the distance to the main urban pole approaches, consequence of a strong human insertion. Romanian standards were used for comparison (MEWM, 2006.

  14. The Concentration Levels Of Some Isotopic Radionuclides In The Coastal Sediments Of The Red Sea, Egypt

    The radionuclide activities of 238U, 232Th, 40K and 137Cs were measured using high resolution gamma spectrometry system. The total organic matter (TOM) and carbonate contents were also measured in the surface sediments of three valleys downstream at the southern Egyptian Red Sea coast. These localities are characterized by the presence of mangrove swamps with dense aerobic roots that provide calm conditions for particulate and fine sediments settlement. 238U and 232Th recorded almost equal activity values in the studied localities and their occurrence in the localities indicated that the metal accumulation are due to the complex and multiple processes that characterize the mangrove environments including accumulation in particulate form with the fine sediments, absorption on iron and manganese oxides and hydroxides from the sea water, incorporation inside the carbonate frameworks and as detrital phase. 40K showed obvious radioactivity in the three localities indicating the presence of terrestrial radionuclide. 137Cs concentrations were not evident in the studied localities which may indicate non-significant artificial source of radionuclide activity.

  15. Heavy metal concentrations in sediment cores from the northern Baltic Sea: Declines over the last two decades

    Highlights: • Trends in Hg, Cd, Cu, Pb, Zn, and As concentrations were investigated in Baltic Sea sediment cores. • Heavy metal deposition in surface sediment of the northern and eastern Baltic Sea is declining. • Arsenic concentrations in sediments from the Bothnian Bay remain at high levels. • Cd and Hg concentrations still occur at unacceptably high levels. - Abstract: The Baltic Sea has received considerable loads of pollutants due to industrialization in Eastern Europe. Concern for the Baltic’s ecological health eventually led to legislation and voluntary measures to limit pollution during the last decades of the 20th century. Heavy metal concentrations in open sea surface sediments reflected these steps to limit contaminant loads almost immediately, suggesting the possibility that the trend would continue in the ensuing years. Recent seafloor samples reveal that the declines have persisted over the past two decades. Currently, almost all heavy metal species have declined in surface sediments to levels approaching the safe limits for humans and the environment. Cadmium and mercury however remain at relatively high concentrations in many areas. Arsenic concentrations, which occur at safe levels within the Gulf of Finland persist at unacceptably high levels in surface sediments of the Bothnian Bay, and thus pose a potential threat to marine life in the area

  16. Effects of suspended sediment concentration and grain size on three optical turbidity sensors

    Merten, Gustavo Henrique; Capel, Paul D.; Minella, Jean P.G.

    2014-01-01

    Purpose: Optical turbidity sensors have been successfully used to determine suspended sediment flux in rivers, assuming the relation between the turbidity signal and suspended sediment concentration (SSC) has been appropriately calibrated. Sediment size, shape and colour affect turbidity and are important to incorporate into the calibration process. Materials and methods: This study evaluates the effect of SSC and particle size (i.e. medium sand, fine sand, very fine sand, and fines (silt + clay)) on the sensitivity of the turbidity signal. Three different turbidity sensors were used, with photo detectors positioned at 90 and 180 degrees relative to the axis of incident light. Five different sediment ratios of sand:fines (0:100, 25:75, 50:50, 75:25 and 100:0) were also evaluated for a single SSC (1000 mg l-1). Results and discussion: The photo detectors positioned at 90 degrees were more sensitive than sensor positioned at 180 degrees in reading a wide variety of grain size particles. On average for the three turbidity sensors, the sensitivity for fines were 170, 40, and 4 times greater than sensitivities for medium sand, fine sand, and very fine sand, respectively. For an SSC of 1000 mg l-1 with the treatments composed of different proportions of sand and fines, the presence of sand in the mixture linearly reduced the turbidity signal. Conclusions: The results indicate that calibration of the turbidity signal should be carried out in situ and that the attenuation of the turbidity signal due to sand can be corrected, as long as the proportion of sand in the SSC can be estimated.

  17. Spatial Evaluation of Heavy Metals Concentrations in the Surface Sediment of Taihu Lake

    Yong Niu

    2015-11-01

    Full Text Available With regard to the size of China’s freshwater lakes, Taihu Lake ranks third and it plays an important role in the supply of drinking water, flood prevention, farming and navigation, as well as in the travelling industry. The problem of environmental pollution has attracted widespread attention in recent years. In order to understand the levels, distribution and sources of heavy metals in sediments of Taihu Lake, random selection was carried out to obtain 59 samples of surface sediment from the entire lake and study the concentrations of Pb, Cd, Cu, Zn, Cr and Ni. Toxic units were also calculated to normalize the toxicities caused by various heavy metals. As a result, Cd and Cu in sediment were considered lower than the effect range low (ERL at all regions where samples were gathered, while Pb and Ni were categorized into ERL-effect range median (ERM at over 22% of the regions where samples were obtained. Nevertheless, all average concentrations of the samples were below the level of potential effect. According to the findings of this research, significant spatial heterogeneity existed in the above heavy metals. In conclusion, the distribution areas of heavy metals with higher concentrations were mainly the north bays, namely Zhushan Bay, Meiliang Bay as well as Gonghu Bay. The distribution areas of Cu, Zn, Cr and Ni with higher concentration also included the lake’s central region, whereas the uniform distribution areas of those with lower concentrations were the lake’s southeast region. In addition, it was most probable that the spatial distribution of heavy metals was determined by river inputs, whereas atmospheric precipitation caused by urban and traffic contamination also exerted considerable effects on the higher concentrations of Pb and Cd. Through evaluating the total amount of toxic units (ΣTU, it was found that higher toxicity existed primarily in the north bays and central region of the lake. If the heavy metals were sorted by

  18. Spatial Evaluation of Heavy Metals Concentrations in the Surface Sediment of Taihu Lake.

    Niu, Yong; Jiao, Wei; Yu, Hui; Niu, Yuan; Pang, Yong; Xu, Xiangyang; Guo, Xiaochun

    2015-12-01

    With regard to the size of China's freshwater lakes, Taihu Lake ranks third and it plays an important role in the supply of drinking water, flood prevention, farming and navigation, as well as in the travelling industry. The problem of environmental pollution has attracted widespread attention in recent years. In order to understand the levels, distribution and sources of heavy metals in sediments of Taihu Lake, random selection was carried out to obtain 59 samples of surface sediment from the entire lake and study the concentrations of Pb, Cd, Cu, Zn, Cr and Ni. Toxic units were also calculated to normalize the toxicities caused by various heavy metals. As a result, Cd and Cu in sediment were considered lower than the effect range low (ERL) at all regions where samples were gathered, while Pb and Ni were categorized into ERL-effect range median (ERM) at over 22% of the regions where samples were obtained. Nevertheless, all average concentrations of the samples were below the level of potential effect. According to the findings of this research, significant spatial heterogeneity existed in the above heavy metals. In conclusion, the distribution areas of heavy metals with higher concentrations were mainly the north bays, namely Zhushan Bay, Meiliang Bay as well as Gonghu Bay. The distribution areas of Cu, Zn, Cr and Ni with higher concentration also included the lake's central region, whereas the uniform distribution areas of those with lower concentrations were the lake's southeast region. In addition, it was most probable that the spatial distribution of heavy metals was determined by river inputs, whereas atmospheric precipitation caused by urban and traffic contamination also exerted considerable effects on the higher concentrations of Pb and Cd. Through evaluating the total amount of toxic units (ΣTU), it was found that higher toxicity existed primarily in the north bays and central region of the lake. If the heavy metals were sorted by the reduction of mean

  19. Effects of salinity and particle concentration on sediment hydrodynamics and critical bed-shear-stress for erosion of fine grained sediments used in wetland restoration projects

    Ghose-Hajra, M.; McCorquodale, A.; Mattson, G.; Jerolleman, D.; Filostrat, J.

    2015-03-01

    Sea-level rise, the increasing number and intensity of storms, oil and groundwater extraction, and coastal land subsidence are putting people and property at risk along Louisiana's coast, with major implications for human safety and economic health of coastal areas. A major goal towards re-establishing a healthy and sustainable coastal ecosystem has been to rebuild Louisiana's disappearing wetlands with fine grained sediments that are dredged or diverted from nearby rivers, channels and lakes to build land in open water areas. A thorough geo-hydrodynamic characterization of the deposited sediments is important in the correct design and a more realistic outcome assessment of the long-term performance measures for ongoing coastal restoration projects. This paper evaluates the effects of salinity and solid particle concentration on the re-suspension characteristics of fine-grained dredged sediments obtained from multiple geographic locations along the Gulf coast. The critical bed-shear-stress for erosion has been evaluated as a function of sedimentation time. The sediment hydrodynamic properties obtained from the laboratory testing were used in a numerical coastal sediment distribution model to aid in evaluating sediment diversions from the Mississippi River into Breton Sound and Barataria Bay.

  20. Denitrification activity is closely linked to the total ambient Fe concentration in mangrove sediments of Goa, India

    Fernandes, S.O.; Gonsalves, M.J.B.D.; Michotey, V.D.; Bonin, P.C.; LokaBharathi, P.A.

    ) and prepared as follows: filtered seawater was supplemented with ammonium chloride (0.05 g L-1), potassium nitrate (0.101 g L-1) sodium acetate (0.2 g L-1), sodium succinate (0.2 g L-1), Biotrypticase (1 g L-1) and 20 kPa acetylene (Bonin et al., 2002). 2.... Seawater from the sampling sites was collected in clean, well-rinsed carbuoys and used for media preparation during microbiological analyses. 2.2. Physico-chemical analyses Sediment cores were sectioned at 2 cm intervals to obtain representative...

  1. Concentrations of heavy metals in sediment and organisms during a harmful algal bloom (HAB) at Kun Kaak Bay, Sonora, Mexico

    In early April 2003, fishermen from Kino Bay Sonora alerted us about a massive die-off of fish and mollusks occurring at Kun Kaak Bay. Phytoplankton samples taken on 17 May 2003 reported the presence of a harmful algal bloom composed of Chatonella marina, Chatonella cf. ovata, Gymnodinium catenatum and Gymnodinium sanguineum. On 22 of May, we collected samples of water, sediment and organisms at the affected area. Physicochemical parameters and nutrients were measured in water samples from different depths. Sediment and benthic organisms were analyzed for Cd, Cu, Zn, Pb and Hg. We found concentrations of heavy metals higher than background levels for this area. Cadmium and Lead concentrations in sediment from the HAB area were up to 6x greater than background levels and Cd in mollusks was 8x greater than regulations allow. A relationship between elevated Cd and Pb concentrations in sediment and the survival of toxic dinoflagellates is suspected

  2. Concentrations of heavy metals in sediment and organisms during a harmful algal bloom (HAB) at Kun Kaak Bay, Sonora, Mexico

    Garcia-Hernandez, Jaqueline [Centro de investigacion en Alimentacion y Desarrollo AC (CIAD) Guaymas Unit, Carretera al Varadero Nal. Km 6.6, Apdo. Postal 284, CP 85480 Guaymas, Sonora (Mexico)]. E-mail: jaqueline@cascabel.ciad.mx; Garcia-Rico, Leticia [Centro de investigacion en Alimentacion y Desarrollo AC (CIAD), Carretera a la Victoria Km 0.6, Apdo. Postal 1735, CP 83000 Hermosillo, Sonora (Mexico)]. E-mail: lgarciar@cascabel.ciad.mx; Jara-Marini, Martin E. [Centro de investigacion en Alimentacion y Desarrollo AC (CIAD), Carretera a la Victoria Km 0.6, Apdo. Postal 1735, CP 83000 Hermosillo, Sonora (Mexico)]. E-mail: mjara@cascabel.ciad.mx; Barraza-Guardado, Ramon [Departamento de Investigaciones Cientificas y Tecnologicas de la Universidad de Sonora (DICTUS), Rosales y Ninos Heroes s/n Col. Centro, CP 83000 Hermosillo, Sonora (Mexico)]. E-mail: rbarraza@rtn.uson.mx; Hudson Weaver, Amy [Comunidad y Biodiversidad AC - COBI, Terminacion Bahia de Bacochibampo s/m, Fraccionamiento Lomas de Cortes, CP 85450 Guaymas, Sonora (Mexico)]. E-mail: ahw@cobi.org.mx

    2005-07-01

    In early April 2003, fishermen from Kino Bay Sonora alerted us about a massive die-off of fish and mollusks occurring at Kun Kaak Bay. Phytoplankton samples taken on 17 May 2003 reported the presence of a harmful algal bloom composed of Chatonella marina, Chatonella cf. ovata, Gymnodinium catenatum and Gymnodinium sanguineum. On 22 of May, we collected samples of water, sediment and organisms at the affected area. Physicochemical parameters and nutrients were measured in water samples from different depths. Sediment and benthic organisms were analyzed for Cd, Cu, Zn, Pb and Hg. We found concentrations of heavy metals higher than background levels for this area. Cadmium and Lead concentrations in sediment from the HAB area were up to 6x greater than background levels and Cd in mollusks was 8x greater than regulations allow. A relationship between elevated Cd and Pb concentrations in sediment and the survival of toxic dinoflagellates is suspected.

  3. Suspended sediment concentration and particle size distribution, and their relationship with heavy metal content

    S H R Sadeghi; M Kiani Harchegani; H A Younesi

    2012-02-01

    This paper aims at assessing the feasibility of suspended sediment concentration (SSC) estimation by using predictor variables of heavy metal concentration (HMC, viz., iron, chromium, zinc and nickel) transported in solution and solid. The study was conducted in the Research and Educational Forest Watershed of the Tarbiat Modares University (Kojour) which comprises an area of ca. 50000 ha. For this study, suspended sediment samples were collected from the left bank of the Kojour River twice a week, as well as during runoff events from November 2007 to June 2008. The samples were then prepared through direct digestion and finally analyzed by atomic absorption spectrophotometry (AAS). The relationship between SSC and particle size distribution (PSD) were correlated with HMC by using bivariate and multivariate regression models. Proposed models were then selected based on statistical criteria. The results showed high correlation between dissolved and particulate chromium content with efficiency coefficients beyond 77% ( > 0.001). However, a lower relationship was found between SSC and nickel content. From these results, it is clearly shown that the HMC can practically be estimated by SSC in watersheds with different accuracy and vice versa. It is also understood that heavy metal pollution can be easily managed by controlling SSC.

  4. Reducing sediment concentration and soil loss using organic and inorganic amendments at plot scale

    Sadeghi, S. H. R.; Gholami, L.; Homaee, M.; Khaledi Darvishan, A.

    2015-04-01

    Various organic and inorganic mulches are used for soil conservation purposes, the effectiveness of which on soil characteristics has not been comprehensively considered from different aspects. The present study surveys the efficiency of straw mulch, manure and TA-200 polyacrylamide with respective rates of 500, 300 and 50 g m-2 in changing sediment concentration and soil loss. The experiments were conducted for sandy-loam soil taken from a summer rangeland, the Alborz Mountains, northern Iran. The experiments were performed under laboratory conditions with simulated rainfall intensities of 30, 50, 70 and 90 mm h-1 and a slope of 30%. The results showed that the straw mulch decreased soil erosion at rate of 45.60% compared to the control plots and performed better than manure (8.98% reduction) and PAM (4.74% reduction). The results showed that the maximum reduction in sediment concentration and soil loss for all soil amendments occurred at the rainfall intensity of 90 mm h-1 with the rates of 58.69 and 63.24% for straw mulch, 14.65 and 13.14% for manure and 20.15 and 23.44% for TA-200.

  5. A MATHEMATICAL MODEL TO PREDICT NICKEL CONCENTRATION IN KARAJ RIVER SEDIMENTS

    R. Ramezankhani, A. A. M. Sharif, M. T. Sadatipour, R.Abdolahzadeh

    2008-04-01

    Full Text Available The contamination of surface waters through human activities has been intensified over the past years as population density has increased. Nickel is a metallic element and fuel combustion, nickel mining, refining waste, sewage sludge, and incineration are the major sources of nickel propagation. Nickel from various industrial wastewaters and other sources finally are disposed into water bodies. In this work, Karaj river was considered from 50º to 50º 14´longitudes and 35º 45´ to 35º 58´ latitudes and the presence of nickel was also assessed in this area. Sixteen stations were randomly selected and sediment samples were collected in polyethylene containers. Some water quality parameters such as pH, temperature, dissolved oxygen, electrical conductivity, were determind by direct on-site measurements. To measure COD, 16 water samples were collected in dark bottles and transferred to laboratory spatial parameters such as slope and distance from start point were also calculated by ARCGIS 9.2. The relation between Ni concentration with spatial parameters and water quality parameters were obtained by multivariate analysis. Results showed that there was a significant relation between Ni concentration in sediments and distance from start point and electrical conductivity.

  6. Spatiotemporal Trends Analysis of Pyrethroid Sediment Concentrations Spanning 10 Years in a Residential Creek in California.

    Hall, Lenwood W; Anderson, Ronald D; Killen, William D

    2016-02-01

    The objective of this study was to assess temporal and spatial trends for eight pyrethroids monitored in sediment spanning 10 years from 2006 to 2015 in a residential stream in California (Pleasant Grove Creek). The timeframe for this study included sampling 3 years during a somewhat normal non-drought period (2006-2008) and 3 years during a severe drought period (2013-2015). Regression analysis of pyrethroid concentrations in Pleasant Grove Creek for 2006, 2007, 2008, 2012, 2013, 2014, and 2015 using ½ the detection limit for nondetected concentrations showed statistically significant declining trends for cyfluthrin, cypermethrin, deltamethrin, permethrin, and total pyrethoids. Additional trends analysis of the Pleasant Grove Creek pyrethroid data using only measured concentrations, without nondetected values, showed similar statistically significant declining trends for cyfluthrin, cypermethrin, deltamethrin, esfenvalerate, fenpropathrin, permethrin, and total pyrethroids. Spatial trends analysis for the specific creek sites showed that six of the eight pyrethroids had a greater number of sites with statistically significant declining concentrations. Possible reasons for reduced pyrethroid concentrations in the stream bed in Pleasant Grove Creek during this 10-year period are label changes in 2012 that reduced residential use and lack of precipitation during the later severe drought years of 2013-2015. PMID:26643307

  7. Quartz concentration as an index of sediment mixing: hydraulic mine-tailings in the Sierra Nevada, California

    Allan James, L.

    1991-06-01

    Hydraulic gold mining delivered large volumes of sediment to northern California stream channels from 1853 to 1884. Distinctive quartz compositions of this sediment allow development of a sediment mixing index for determination of tailings concentrations in contemporaneous and reworked deposits. This index reveals patterns of sediment mixing in the Bear River, California over the last 100 years. A conceptual model summarizes the nature of sediment mixing in the Bear River basin through time and space. High terrace sediment compositions suggest that hydraulic mining sediment was diluted by about 22% other alluvium as it moved more than 60 km to the Sacramento Valley. This substantial volume of other alluvium was introduced during the mining period by human activities in addition to hydraulic mining. Sediment compositions in modern low-flow channels indicate that most channel reaches within the mining districts remain dominated by tailings due to sustained reworking of stored alluvium. Tailings are substantially diluted downstream in modern channel deposits, however, due to trapping of sediment by dams and local erosion of Quarternary alluvium.

  8. Concentration of Antifouling Biocides and Metals in Sediment Core Samples in the Northern Part of Hiroshima Bay

    Noritaka Tsunemasa

    2014-06-01

    Full Text Available Accumulation of Ot alternative antifoulants in sediment is the focus of this research. Much research had been done on surface sediment, but in this report, the accumulation in the sediment core was studied. The Ot alternative antifoulants, Diuron, Sea-Nine211, and Irgarol 1051, and the latter’s degradation product, M1, were investigated in five samples from the northern part of Hiroshima Bay. Ot compounds (tributyltin (TBT and triphenyltin (TPT were also investigated for comparison. In addition, metal (Pb, Cu, Zn, Fe and Mn levels and chronology were measured to better understand what happens after accumulation on the sea floor. It was discovered that Ot alternative antifoulant accumulation characteristics in sediment were like Ot compounds, with the concentration in the sediment core being much higher than surface sediment. The concentration in sediment seems to have been affected by the regulation of Ot compounds in 1990, due to the concentration of Ot alternative antifoulants and Ot compounds at the survey point in front of the dock, showing an increase from almost the same layer after the regulation.

  9. Minimal inhibitory concentrations of undissociated lactic, acetic, citric and propionic acid for Listeria monocytogenes under conditions relevant to cheese

    Wemmenhove, Ellen; Valenberg, van Hein J.F.; Zwietering, Marcel H.; Hooijdonk, van Toon C.M.; Wells-Bennik, Marjon H.J.

    2016-01-01

    Minimal inhibitory concentrations (MICs) of undissociated lactic acid were determined for six different Listeria monocytogenes strains at 30 °C and in a pH range of 4.2-5.8. Small increments in pH and acid concentrations were used to accurately establish the growth/no growth limits of L. monocyto

  10. Uranium hydrogeochemical and stream sediment reconnaissance of the Craig NTMS Quadrangle, Colorado, including concentrations of forty-three additional elements

    A hydrogeochemical and stream sediment reconnaissance for uranium in the Craig NTMS Quadrangle, Colorado, was conducted as part of the National Uranium Resource Evaluation. Totals of 1234 water and 1732 sediment samples were collected from 1743 locations over a 18,900 km2 area at an average density of one location per 11 km2. Water and/or sediment samples were collected from streams and springs. All water samples were analyzed for uranium and 12 other elements. Sediment samples were analyzed for uranium, thorium, and 41 additional elements. The uranium concentrations in water samples range from below 0.02 ppB to 856.44 ppB. The recalculated mean uranium concentration for all water types is 1.55 ppB. The recalculated mean was obtained after dropping five samples with values greater than 50.00 ppB. Waters with anomalous uranium concentrations were found in tributaries of streams that drain upper Cretaceous formations southwest of Craig, north of the Williams Fork Mountains, in Middle Park, and in an area underlain by Tertiary volcanics in the southeast corner of the Craig Quadrangle. Sediment samples from the quadrangle were found to have uranium concentrations that range from 1.53 ppM to 385.60 ppM, with a recalculated mean uranium concentration for all sediments of 6.23 ppM. The recalculated mean was obtained after dropping 13 samples with values greater than 50.00 ppM. Eight areas containing clusters of sediments with anomalous uranium concentrations are delineated. The two areas containing sediment samples with the highest uranium concentrations are in the Sand Wash basin and in the Park Range northeast of Steamboat Springs. Thorium concentrations in sediment samples range from 1.10 ppM to 1596.00 ppM with a mean of 26.75 ppM. Seven areas contain clusters of samples with individual thorium concentrations greater than 70 ppM. The areas containing the highest thorium values coincide with clusters of high uranium sediment samples in the Sand Wash basin

  11. Natural Uranium concentrations in surface water and sediments from former Uranium mining locations for 2012–2013

    Uranium is consistently redistributed in the environment by natural processes that may be affected by anthropogenic factors. One of the primary industrial processes that cause this redistribution is uranium mining. Waters and bottom sediments in the region of 29 former uranium mining sites in Bulgaria were studied to assess the pollution as a result of the discharge of groundwater from former mine works. Results on the uranium concentration in 68 water samples and 48 sediment samples are presented. The concentrations of natural uranium in water were determined by spectrophotometric analysis and, in sediment, by gamma-ray spectrometry. The range of uranium concentrations in water samples for the points of mine discharge (adits, tunnels, drain water conduits) ranges from 0.02 to 6.80 mg U/l, and in sediment samples – from 2.23 to 317 mg U/kg. The regional background concentration of uranium in water is below the minimum detectable quantity (0.01 mgU/l) and for sediments – from 1.23 to 12.7 mg U/kg. The distribution coefficient which describes uranium sorption to sediment was assessed in the study and can be used to justify the necessary reclamation activities. (author)

  12. Computing time-series suspended-sediment concentrations and loads from in-stream turbidity-sensor and streamflow data

    Rasmussen, Patrick P.; Gray, John R.; Glysson, G. Doug; Ziegler, Andrew C.

    2010-01-01

    Over the last decade, use of a method for computing suspended-sediment concentration and loads using turbidity sensors—primarily nephelometry, but also optical backscatter—has proliferated. Because an in- itu turbidity sensor is capa le of measuring turbidity instantaneously, a turbidity time series can be recorded and related directly to time-varying suspended-sediment concentrations. Depending on the suspended-sediment characteristics of the measurement site, this method can be more reliable and, in many cases, a more accurate means for computing suspended-sediment concentrations and loads than traditional U.S. Geological Survey computational methods. Guidelines and procedures for estimating time s ries of suspended-sediment concentration and loading as a function of turbidity and streamflow data have been published in a U.S. Geological Survey Techniques and Methods Report, Book 3, Chapter C4. This paper is a summary of these guidelines and discusses some of the concepts, s atistical procedures, and techniques used to maintain a multiyear suspended sediment time series.

  13. Central Colorado Assessment Project (CCAP)-Geochemical data for rock, sediment, soil, and concentrate sample media

    Granitto, Matthew; DeWitt, Ed H.; Klein, Terry L.

    2010-01-01

    This database was initiated, designed, and populated to collect and integrate geochemical data from central Colorado in order to facilitate geologic mapping, petrologic studies, mineral resource assessment, definition of geochemical baseline values and statistics, environmental impact assessment, and medical geology. The Microsoft Access database serves as a geochemical data warehouse in support of the Central Colorado Assessment Project (CCAP) and contains data tables describing historical and new quantitative and qualitative geochemical analyses determined by 70 analytical laboratory and field methods for 47,478 rock, sediment, soil, and heavy-mineral concentrate samples. Most samples were collected by U.S. Geological Survey (USGS) personnel and analyzed either in the analytical laboratories of the USGS or by contract with commercial analytical laboratories. These data represent analyses of samples collected as part of various USGS programs and projects. In addition, geochemical data from 7,470 sediment and soil samples collected and analyzed under the Atomic Energy Commission National Uranium Resource Evaluation (NURE) Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) program (henceforth called NURE) have been included in this database. In addition to data from 2,377 samples collected and analyzed under CCAP, this dataset includes archived geochemical data originally entered into the in-house Rock Analysis Storage System (RASS) database (used by the USGS from the mid-1960s through the late 1980s) and the in-house PLUTO database (used by the USGS from the mid-1970s through the mid-1990s). All of these data are maintained in the Oracle-based National Geochemical Database (NGDB). Retrievals from the NGDB and from the NURE database were used to generate most of this dataset. In addition, USGS data that have been excluded previously from the NGDB because the data predate earliest USGS geochemical databases, or were once excluded for programmatic reasons

  14. Secondary grain-size effects on Li and Cs concentrations and appropriate normalization procedures for coastal sediments

    Jung, Hoisoo; Lim, Dhongil; Xu, Zhaokai; Jeong, Kapsik

    2016-06-01

    The sediment grain-size effect (GSE), a fundamental factor relevant to the interpretation of elemental concentrations and isotopic compositions, has been normalized using conservative elements such as aluminum (Al), cesium (Cs), and lithium (Li) (C(Al,Cs,Li)), which serve as proxies for the natural metal-controlling variables of grain size, mineralogy, and organic matter. However, a secondary GSE reportedly remains even after compensation by the Al-normalization procedure, particularly for the concentrations of transition metals (CT.M). This secondary effect also occurred in the C(Li,Cs)/CAl ratios of the Korean coastal sediments examined in this study. The primary and secondary GSEs on Cs and Li concentrations can be explained by the quartz-dilution effect and the Cs- and Li-incorporation effect of phyllosilicate minerals, respectively, based on a model involving three component end-members: a Cs- and Li-free sand-dominated sediment component consisting mostly of quartz and feldspar, a Cs- and Li-bearing silt-dominated component of mica, and a Cs- and Li-enriched clay-dominated component of illite. Although the primary and secondary GSEs on the concentrations of transition metals (particularly Cu and Ni) in coastal sediments might be normalized by dividing the metal concentrations by the square of the Al concentration (CT.M./(CAl)2), the GSEs can also be normalized by dividing the concentrations by the exact Cs (or Li) concentration (CT.M./CCs).

  15. Estimation of suspended sediment concentrations using Terra MODIS: an example from the Lower Yangtze River, China.

    Wang, J-J; Lu, X X

    2010-02-01

    Traditional measurements of suspended sediment concentrations (SSC) through in-situ sampling in rivers are expensive and time-consuming to perform. Thus, these methods cannot provide continuous SSC records. Although remote sensing has been used for SSC estimation, little research has been undertaken on inland rivers, especially for highly turbid rivers like the Yangtze. Previous studies have proposed Landsat TM/ETM+ Band 4 as a spectral SSC indicator for the Yangtze, but its limitation on temporal resolution is insufficient for the study of dynamic changes of sediment. This paper presents a method of estimating SSC of the Yangtze at Jiujiang using time-series satellite data of high temporal resolution Terra MODIS. It was found that differences in water reflectance between Band 2 and Band 5 could provide relatively accurate SSC estimation even when in-situ atmospheric conditions were unknown. After cross-validation, mean absolute relative error (ARE) and relative root mean square error (RRMSE) were relatively low (i.e., 25.5% and 36.5%, respectively). This empirical relationship was successfully applied to the estimation of SSC at Datong in the Lower Yangtze River, although the SSC values were generally underestimated. This study suggests that Terra MODIS could be used to estimate SSC in large turbid rivers, although some influencing factors require further study to improve the accuracy of SSC estimation. PMID:20022078

  16. Evaluation of data driven models for river suspended sediment concentration modeling

    Zounemat-Kermani, Mohammad; Kişi, Özgür; Adamowski, Jan; Ramezani-Charmahineh, Abdollah

    2016-04-01

    Using eight-year data series from hydrometric stations located in Arkansas, Delaware and Idaho (USA), the ability of artificial neural network (ANN) and support vector regression (SVR) models to forecast/estimate daily suspended sediment concentrations ([SS]d) was evaluated and compared to that of traditional multiple linear regression (MLR) and sediment rating curve (SRC) models. Three different ANN model algorithms were tested [gradient descent, conjugate gradient and Broyden-Fletcher-Goldfarb-Shanno (BFGS)], along with four different SVR model kernels [linear, polynomial, sigmoid and Radial Basis Function (RBF)]. The reliability of the applied models was evaluated based on the statistical performance criteria of root mean square error (RMSE), Pearson's correlation coefficient (PCC) and Nash-Sutcliffe model efficiency coefficient (NSE). Based on RMSE values, and averaged across the three hydrometric stations, the ANN and SVR models showed, respectively, 23% and 18% improvements in forecasting and 18% and 15% improvements in estimation over traditional models. The use of the BFGS training algorithm for ANN, and the RBF kernel function for SVR models are recommended as useful options for simulating hydrological phenomena.

  17. An evaluation of selenium concentrations in water, sediment, invertebrates, and fish from the Solomon River Basin

    May, T.W.; Fairchild, J.F.; Petty, J.D.; Walther, M.J.; Lucero, J.; Delvaux, M.; Manring, J.; Armbruster, M.

    2008-01-01

    The Solomon River Basin is located in north-central Kansas in an area underlain by marine geologic shales. Selenium is an indigenous constituent of these shales and is readily leached into the surrounding groundwater. Portions of the Basin are irrigated primarily through the pumping of selenium-contaminated groundwater from wells onto fields in agricultural production. Water, sediment, macroinvertebrates, and fish were collected from various sites in the Basin in 1998 and analyzed for selenium. Selenium concentrations were analyzed spatially and temporally and compared to reported selenium toxic effect thresholds for specific ecosystem components: water, sediments, food-chain organisms, and wholebody fish. A selenium aquatic hazard assessment for the Basin was determined based on protocol established by Lemly. Throughout the Basin, water, macroinvertebrate, and whole fish samples exceeded levels suspected of causing reproductive impairment in fish. Population structures of several fish species implied that successful reproduction was occurring; however, the influence of immigration of fish from low-selenium habitats could not be discounted. Site-specific fish reproduction studies are needed to determine the true impact of selenium on fishery resources in the Basin. ?? Springer Science+Business Media B.V. 2007.

  18. Evaluating suitability of MODIS-Terra images for reproducing historic sediment concentrations in water bodies: Lake Tana, Ethiopia

    Kaba, Essayas; Philpot, William; Steenhuis, Tammo

    2014-02-01

    Government and NGO funded conservation programs are being implemented in developing countries with the potential benefit of reduced sediment inflow into fresh water lakes. However, these claims are difficult to verify due to limited historical sediment concentration data in lakes and rivers. Remote sensing can potentially aid in monitoring sediment concentration. With almost daily availability over the past ten years and consistent atmospheric correction applied to the images, Moderate Resolution Imaging Spectroradiometer (MODIS) 250 meter images are potential resources capable of monitoring future concentrations and reconstructing historical sediment concentration records. In this paper, site-specific relationships are developed between reflectance in near-infrared (NIR) images and three factors: total suspended solids (TSS), turbidity and Secchi depth for Lake Tana near the mouth of the Gumara River. The first two sampling campaigns on November 27, 2010 and May 13, 2011 are used in calibration. Reflectance in the NIR varies linearly with turbidity (R2 = 0.89) and TSS (R2 = 0.95). Secchi depth fit best to an exponential relation with R2 of 0.74. The relationships are validated using a third sample set collected on November 7, 2011 with RMSE of 11 Nephelometric Turbidity Units (NTU) for Turbidity, 16.5 mg l-1 for TSS and 0.12 meters for Secchi depth. The MAE was 10% for TSS, 14% for turbidity and 0.1% for Secchi depth. Using the relationship for TSS, a 10-year time series of sediment concentration in Lake Tana near the Gumara River was plotted. It was found that after the severe drought of 2002 and 2003 the concentration in the lake increased significantly. The results showed that MODIS images are potential cost effective tools to monitor suspended sediment concentration and obtain a past history of concentration for evaluating the effect of best management practices.

  19. Investigating high zircon concentrations in the fine fraction of stream sediments draining the Pan-African Dahomeyan Terrane in Nigeria

    Sixteen hundred stream sediments (<150 μm fraction) collected during regional geochemical surveys in central and SW Nigeria have high median and maximum concentrations of Zr that exceed corresponding Zr concentrations found in stream sediments collected from elsewhere in the World with similar bedrock geology. X-ray diffraction studies on a sub-set of the analysed stream sediments showed that Zr is predominantly found in detrital zircon grains. However, the main proximal source rocks (Pan-African ‘Older Granites’ of Nigeria and their Proterozoic migmatitic gneiss country rocks) are not enriched in zircon (or Zr). Nevertheless, U–Pb LA-ICP-MS dating with cathodoluminescence imaging on detrital zircons, both from stream sediment samples and underlying Pan-African ‘Older Granites’ confirms a local bedrock source for the stream sediment zircons. A combination of tropical/chemical weathering and continuous physical weathering, both by ‘wet season’ flash flooding and ‘dry season’ unidirectional winds are interpreted to have effectively broken down bedrock silicate minerals and removed much of the resultant clay phases, thereby increasing the Zr contents in stream sediments. The strong correlation between winnowing index (Th/Al) and Zr concentration across the study area support this interpretation. Therefore, ‘anomalous’ high values of Zr, as well as other elements concentrated in resistant ‘heavy’ minerals in Nigeria’s streams may not reflect proximal bedrock concentrations of these elements. This conclusion has important implications for using stream sediment chemistry as an exploration tool in Nigeria for primary metal deposits associated with heavy minerals.

  20. Preparing Process of Cerium Acetate and Rare Earth Acetate

    Qiao Jun; Ma Ying; Xu Yanhui; Zhang Jun; Chang Shu; Hao Xianku

    2004-01-01

    Preparing process was presented and the influences of concentration of acetic acid, reaction temperature, the ratio of cerium carbonate and acetic acid, heat preservation time to the yield of cerium acetate were discussed.The crystalline cerium acetate and rare earth acetate such as ( La, Ce, Pr, Nd) (Ac) 3, ( Ce, Pr, Nd) (Ac) 3, ( Pr, Nd, Er,Y) (Ac) 3 and yttrium acetate were prepared under this condition.The shape, structure and composition of the crystals were determined by the methods of SEM, TG-DTA, X-ray diffraction and chemical analysis.The optimum prepared conditions of cerium acetate were described.This prepared process has characteristics such as simple process route, low cost, high yield, good quality, no pollution to environment, etc.

  1. Radiocarbon concentration of lake sediment cellulose from Lake Erhai in southwest China

    To improve age models for lake sediment cores without suitable 14C dating materials such as terrestrial plant fossils, we investigated the radiocarbon dating of lake sediment cellulose. The cellulose fraction in the sediments was obtained by a sequential decomposition of other organic matter, and subsequently dated by AMS. In general, 14C ages of the lake sediment cellulose obtained from a 10-m sediment core from Lake Erhai on the Yunnan-Guizhou Plateau are in agreement with 14C dates from terrestrial plant fossils. For the early Holocene, however, differences of up to 1000 14C years are observed between lake sediment cellulose and terrestrial plant fossils. This disagreement is probably caused by the contribution of 14C-depleted cellulose synthesized by aquatic plants/algae in the lake. To obtain a precise and accurate chronology based on 14C ages of lake sediment cellulose, the origin of lake sediment cellulose needs to be established

  2. CONCENTRATIONS OF Cd, Cu AND Zn IN SEDIMENTS COLLECTED FROM URBAN LAKES AT KELANA JAYA, PENINSULAR MALAYSIA

    Ahmad Ismail; Chee Kong YAP; Fong Fei Chan

    2004-01-01

    Kelana Jaya Municipal Park is a popular recreation park in Petaling Jaya. The five lakes, located within the Park, were ex-mining ponds, functioning as flood retention ponds and receiving effluents from nearby human activities mainly from residents and transportation. A study was conducted to determine the distribution and sources of heavy metals (Cd, Cu and Zn) in the sediments of Kelana Jaya Lakes. Concentrations of Cd, Cu, and Zn for surface sediment were determined by using aqua-regia method and sequential extraction technique. Total Cd concentrations ranged from 0.48 μg/g to 2.68 μg/g dry weight (dw) for all lakes. Total Cd concentrations in sediment of all lakes exceeded CCME (Canadian Council of Ministers of the Environment, 2001) guidelines. Total Cu concentrations ranged from 7.37μg/g to 73.6 μg/g (dw). Only Cu concentration in one lake exceeded the CCME guidelines besides having the highest mean concentration among all. Total Zn concentrations ranged from 107 μg/g to 529 μg/g (dw). Again, The Zn concentrations in three lakes were found to exceed CCME guidelines for Zn concentration in freshwater sediment. Geochemical study on sediment revealed that nonresistant fractions for Cd, Cu and Zn for other lakes there Cu and Zn indicated that lakes in the park, especially near oxidation pond and monsoon drains, could have received anthropogenic metals from domestic wastes. Rehabilitation program and regular biomonitoring at Kelana Jaya Lakes are therefore recommended.

  3. Heavy metal concentration in marine sediments and vegetation (caltha palustrvis) from river ramos in bayelsa and delta states of nigeria

    Heavy metals concentration in marine sediments and vegetation from River Ramos have been studied. Metals such as arsenic, mercury, cadmium, lead, chromium, nickel, iron, copper and zinc were analysed using atomic absorption spectrometer (AAS). The levels of these metals were determined from top and bottom river sediments, side and middle vegetation. The analytical results revealed that arsenic levels were high in all the samples. Secondly, the highest concentration of metals were found on the top sediment (68.00mg/kg dry weight) and vegetation (64.90mg/kg dry weight). Other metals such as mercury, chromium, nickel and iron were found to have high levels. The high levels of the above mentioned heavy metals are the cause of pollution, the concentration due to other metals such as cadmium, lead, copper and zinc was low. The high accumulation of heavy metals in the matrices are due to activities of oil companies and geochemistry of rocks. (author)

  4. Evaluation of suspended sediment concentrations in a hydropower reservoir by using a Laser In-Situ Scattering and Transmissometry instrument

    Lizano, Laura; Haun, Stefan

    2014-05-01

    Sediment transported by rivers start to settle when they enter a reservoir due to reduced flow velocities and turbulences. Reservoir sedimentation is a common problem today and eliminates about 1% of the worldwide existing storage capacity annually. However, depending on the climate conditions and the geology in the catchment area this value can increase up to 5% and higher. Among the results of reservoir deposition is the loss of the storage capacity, a loss of flood control benefits or even blockage of intakes due to sediment accumulation in front of the structure. As a consequence, management tasks have to be planned and conducted to guarantee a safe and economical reservoir operation. A major part of the sediment particles entering the reservoir is transported as suspended sediment load. Hence, accurate knowledge of the transport processes of these particles in the reservoir is advantageous for planning and predicting a sustainable reservoir operation. Of special interest is the spatial distribution of the grain sizes in the reservoir, for example, which grain sizes can be expected to enter the waterway and have a major contribution in turbine abrasion. The suspended sediment concentrations and the grain size distribution along the Sandillal reservoir in Costa Rica were measured in this study by using a Laser In-Situ Scattering and Transmissometry instrument (LISST-SL). The instrument measures sediment concentrations as well as the grain size distributions instantaneously (32 grain sizes in the range between 2.1 and 350 μm) with a frequency of 0.5 Hertz. The measurements were applied at different pre-specified transects along the reservoir, in order to assess the spatial distribution of the suspended sediment concentrations. The measurements were performed in vertical lines, at different depths and for a period of 60 seconds. Additionally, the mean grain size distribution was calculated from the data for each measured point. The measurements showed that the

  5. Environmental Risk Limits for Ethylene Diamine Tetra Acetic acid (EDTA)

    Kalf DF; Hoop MAGT van den; Rila JP; Posthuma C; Traas TP; SEC

    2003-01-01

    In this report maximum permissible concentration (MPC) and negligible concentration (NC) in water are derived for Ethylene Diamine Tetra Acetic acid (EDTA; CAS No. 64-02-8, EINECS No. 200-573-9), based on the EU risk assessment report for this compound. The Maximum Permissible Concentration (MPC) for the water compartment is 2.2 mg/l, and the Negligible Concentration (NC) is 0.022 mg/l. Calculation of MPCs for sediment or soil is not possible due to complex speciation of EDTA.

  6. Determination Of Concentrations Of Cs-137 And Pu-239/240 In Sediment From Muria Peninsula And Surrounding

    The determination of concentration of Cs-137 and Pu-239/240 on sediment from Muria Peninsula and Surrounding has been done. The samples were collected from 10 locations. The aim of this research is to get status data of concentrations of Cs-137 and Pu-239/240 in sediment at those locations. Concentration of Cs-137 was determined after drying the sediment, then was measured directly by using Gamma Spectrometer with high pure. Germanium Detector (HPGe), mean while concentration Pu-239/240 was determined by leaching using HNO sub.3 solution, and then separated from other materials by anion exchanger and measured with alpha spectrometer Silicon Surface Barrier Detector. The results show that the concentration of Cs-137 in sediment is in the range of between under lower limit detection (< MDC) value to (0,71 n 0,15) Bq/kg, and the concentrations of Pu-239/240 is in the range of between (< MDC) and (26,47 n 2,98) mBq/kg

  7. Electron donor concentrations in sediments and sediment properties at the agricultural chemicals team research site near New Providence, Iowa, 2006-07

    Maharjan, Bijesh; Korom, Scott F.; Smith, Erik A.

    2013-01-01

    The concentrations of electron donors in aquifer sediments are important to the understanding of the fate and transport of redox-sensitive constituents in groundwater, such as nitrate. For a study by the U.S. Geological Survey National Water-Quality Assessment Program, 50 sediment samples were collected from below the water table from 11 boreholes at the U.S. Geological Survey Agricultural Chemicals Team research site near New Providence, Iowa, during 2006-07. All samples were analyzed for gravel, sand (coarse, medium, and fine), silt, clay, Munsell soil color, inorganic carbon content, and for the following electron donors: organic carbon, ferrous iron, and inorganic sulfide. A subset of 14 sediment samples also was analyzed for organic sulfur, but all of these samples had concentrations less than the method detection limit; therefore, the presence of this potential electron donor was not considered further. X-ray diffraction analyses provided important semi-quantitative information of well-crystallized dominant minerals within the sediments that might be contributing electron donors.

  8. Assessment of sediment concentration and nutrient loads in effluents drained from extensively managed fishponds in France

    Expansion of aquaculture has increased concern over its environmental impact. The composition of effluents from intensive aquaculture is well documented, but few data on extensive aquaculture are available. During 12 draining operations, 523 water samples were collected downstream from six extensively-managed fishponds in northeastern France. Study ponds had surface areas of 2-620 ha and were managed for production of Cyprinids and Percids. Concentrations of total suspended solids, total phosphorus, and Kjeldahl nitrogen in effluents from the ponds were greatest during the final stage of draining. Loads of phosphorus were higher than those reported for effluents of more intensive aquaculture ponds in the USA, but the source of the potential pollutants was catchments and sediment rather than feeds and fertilizer. It will be necessary to reduce the water drawdown rate during the fishing stage and possibly implement other best management practices to prevent the TSS concentration from exceeding 1 g/L. - Effluent phosphorus loads were higher than those reported for more intensive aquaculture ponds, but the pollutant source was catchments rather than feeds and fertilizers

  9. Cytotoxicity of TiO{sub 2} nanoparticles towards freshwater sediment microorganisms at low exposure concentrations

    Kumari, Jyoti; Kumar, Deepak; Mathur, Ankita; Naseer, Arif; Kumar, Ravi Ranjan [Centre for Nanobiotechnology, VIT University, Vellore 632014 (India); Thanjavur Chandrasekaran, Prathna [Department of Materials Engineering, Indian Institute of Science, Bangalore (India); Chaudhuri, Gouri; Pulimi, Mrudula [Centre for Nanobiotechnology, VIT University, Vellore 632014 (India); Raichur, Ashok M. [Department of Materials Engineering, Indian Institute of Science, Bangalore (India); Department of Chemical Technology, University of Johannesburg (South Africa); Babu, S. [School of Bio Sciences and Technology, VIT University, Vellore (India); Chandrasekaran, Natarajan [Centre for Nanobiotechnology, VIT University, Vellore 632014 (India); Nagarajan, R. [Department of Chemical Engineering, IIT Madras, Chennai (India); Mukherjee, Amitava, E-mail: amit.mookerjea@gmail.com [Centre for Nanobiotechnology, VIT University, Vellore 632014 (India)

    2014-11-15

    There is a persistent need to assess the effects of TiO{sub 2} nanoparticles on the aquatic ecosystem owing to their increasing usage in consumer products and risk of environmental release. The current study is focused on TiO{sub 2} nanoparticle-induced acute toxicity at sub-ppm level (≤1 ppm) on the three different freshwater sediment bacterial isolates and their consortium under two different irradiation (visible light and dark) conditions. The consortium of the bacterial isolates was found to be less affected by the exposure to the nanoparticles compared to the individual cells. The oxidative stress contributed considerably towards the cytotoxicity under both light and dark conditions. A statistically significant increase in membrane permeability was noted under the dark conditions as compared to the light conditions. The optical and fluorescence microscopic images showed aggregation and chain formation of the bacterial cells, when exposed to the nanoparticles. The electron microscopic (SEM, TEM) observations suggested considerable damage of cells and bio-uptake of nanoparticles. The exopolysaccrides (EPS) production and biofilm formation were noted to increase in the presence of the nanoparticles, and expression of the key genes involved in biofilm formation was studied by RT-PCR. - Highlights: • Toxicity of NPs towards freshwater sediment bacteria at sub-ppm concentrations. • Decreased toxicity of the nanoparticles in the consortium of microorganisms. • Enhanced bacterial resistance through EPS and biofilm formation in the presence of NPs. • Considerable surface damage of cells and internalization of NPs. • Gene expression analyses related to biofilm formation in the presence of NPs.

  10. Cytotoxicity of TiO2 nanoparticles towards freshwater sediment microorganisms at low exposure concentrations

    There is a persistent need to assess the effects of TiO2 nanoparticles on the aquatic ecosystem owing to their increasing usage in consumer products and risk of environmental release. The current study is focused on TiO2 nanoparticle-induced acute toxicity at sub-ppm level (≤1 ppm) on the three different freshwater sediment bacterial isolates and their consortium under two different irradiation (visible light and dark) conditions. The consortium of the bacterial isolates was found to be less affected by the exposure to the nanoparticles compared to the individual cells. The oxidative stress contributed considerably towards the cytotoxicity under both light and dark conditions. A statistically significant increase in membrane permeability was noted under the dark conditions as compared to the light conditions. The optical and fluorescence microscopic images showed aggregation and chain formation of the bacterial cells, when exposed to the nanoparticles. The electron microscopic (SEM, TEM) observations suggested considerable damage of cells and bio-uptake of nanoparticles. The exopolysaccrides (EPS) production and biofilm formation were noted to increase in the presence of the nanoparticles, and expression of the key genes involved in biofilm formation was studied by RT-PCR. - Highlights: • Toxicity of NPs towards freshwater sediment bacteria at sub-ppm concentrations. • Decreased toxicity of the nanoparticles in the consortium of microorganisms. • Enhanced bacterial resistance through EPS and biofilm formation in the presence of NPs. • Considerable surface damage of cells and internalization of NPs. • Gene expression analyses related to biofilm formation in the presence of NPs

  11. Distribution of 210Pb activity concentrations in marine surface sediments within East Coast Peninsula Malaysia Exclusive Economic Zone (EEZ)

    A sampling expedition into the East Coast Peninsula Malaysia Exclusive Economic Zone (EEZ) was carried in June 2008. Marine surface sediment samples were taken and the activity concentrations of 210Pb have been determined. Its distribution was plotted and the findings show that the activity concentrations decline from north to south. On the other hand, the activity concentrations are increasing from west to east right to the edge of the EEZ. The highest activity concentrations were found to be near offshore oil platforms. The 210Pb activity concentrations were found to be in the range of 18.3 - 123.1 Bq/ kg. (author)

  12. Polycyclic aromatic hydrocarbons and black carbon in intertidal sediments of China coastal zones: Concentration, ecological risk, source and their relationship.

    Li, Xiaofei; Hou, Lijun; Li, Ye; Liu, Min; Lin, Xianbiao; Cheng, Lv

    2016-10-01

    Polycyclic aromatic hydrocarbons (PAHs) and black carbon (BC) have attracted many attentions, especially in the coastal environments. In this study, spatiotemporal distributions of PAHs and BC, and the correlations between BC and PAHs were investigated in the intertidal sediments of China coastal zones. BC in sediments was measured through dichromate oxidation (BCCr) and thermal oxidation (BCCTO). The concentrations of BCCr in the intertidal sediments ranged between 0.61 and 6.32mgg(-1), while BCCTO ranged between 0.57 and 4.76mgg(-1). Spatial variations of δ(13)C signatures in TOC and BC were observed, varying from -21.13‰ to -24.87‰ and from -23.53‰ to -16.78‰, respectively. PAH contents of sediments ranged from 195.9 to 4610.2ngg(-1) in winter and 98.2 to 2796.5ngg(-1) in summer, and significantly seasonal variations were observed at most sampling sites. However, the results of potential toxicity assessment indicated low ecological risk in the intertidal sediments of China coastal zones. Greater concentrations of PAHs measured in the sediments of estuarine environments indicated that rivers runoff may have been responsible for the higher PAH pollution levels in the intertidal sediments of China coastal zones. Pearson's correlation analysis suggested that pyrogenic compounds of PAH were significantly related to BC, due to that both BC and these compounds derived mainly from the combustion process of fossil fuels and biomass. Overall, increasing energy consumptions caused by anthropogenic activities can contribute more emissions of BC as well as PAHs and thus improve the importance of BC in indicating pyrogenic compounds of PAHs in the intertidal sediments of China coastal zones. PMID:27266522

  13. Concentration Levels and Ecological Risks of Persistent Organic Pollutants in the Surface Sediments of Tianjin Coastal Area, China

    Xiaoxia Lu

    2013-01-01

    Full Text Available Sediments were sampled from different surface water bodies in Tianjin coastal area, China, and persistent organic pollutants (POPs including polycyclic aromatic hydrocarbons (PAHs, organochlorine pesticides (OCPs, polychlorinated biphenyls (PCBs, and polybrominated diphenyl ethers (PBDEs were measured using GC/MS or GC/ECD. The purposes were to investigate the concentration levels of the POPs and to assess their ecological risks. The results showed that all the 16 priority PAHs were detected from the 10 sediments sampled with the total concentrations of the 16 PAHs ranging from 274.06 μg/kg to 2656.65 μg/kg, while the concentrations of the halogenated POPs were generally low except in the Dagu waste discharging river where the total concentrations of 24 OCPs, 35 PCBs, and 14 PBDEs were 3103.36 μg/kg, 87.31 μg/kg, and 13.88 μg/kg, respectively. In the studied sediments, PAHs exhibited risks to benthonic organisms; particularly the concentrations of naphthalene and/or acenaphthene exceeded their probable effect concentrations in several locations. In comparison, only in the Dagu waste discharging river, OCPs exhibited risks with the concentrations of heptachlor epoxide and lindane exceeding their probable effect concentrations. PCBs and PBDEs posed rare risks in the studied area.

  14. Comparison of contaminant concentrations on surface sediments and in surface water in White Oak Creek Embayment

    Department of Energy activities at Oak Ridge National Laboratory have released 137Cs and other contaminants to White Oak Creek which drains directly into the Clinch River and Watts Bar Reservoir. The largest annual releases occurred in the mid-1950s, but have been significantly reduced since the 1960s. Contaminated sediments have accumulated in the White Oak Creek Embayment (WOCE), an arm of Watts Bar. Highly contaminated sediment, containing 137Cs level corresponding to peak release values, had been buried deep in embayment sediments. However, recent sediment data show that these high 137Cs levels are now observed at the sediment surface. This study, performed in order to further characterize contamination of WOCE sediments and surface water, is part of the site characterization and contaminant screening study for WOCE

  15. Factors affecting metal concentrations in the upper sediment layer of intertidal reedbeds along the river Scheldt

    Du Laing, G; Vandecasteele, Bart; P. DE GRAUWE; Moors, W; Lesage, E.; Meers, E; Tack, F.M.G.; Verloo, M.G.

    2007-01-01

    Factors that play a role in determining metal accumulation in sediments of 26 intertidal marshes which are mainly vegetated by reed plants (Phragmites australis) were assessed along the Scheldt estuary (Belgium and The Netherlands). In the upper 20 cm sediment layer, several physico-chemical properties (clay, silt and sand content, organic matter, carbonate and chloride content, pH and conductivity) and aqua regia extractable metals (Cd, Cr, Cu, Ni, Pb, Zn) were determined. The sediments were...

  16. Suppression of local haze variations in MERIS images over turbid coastal waters for retrieval of suspended sediment concentration

    Shen, F.; Verhoef, W.

    2010-01-01

    Atmospheric correction over turbid waters can be problematic if atmospheric haze is spatially variable. In this case the retrieval of water quality is hampered by the fact that haze variations could be partly mistaken for variations in suspended sediment concentration (SSC). In this study we propose

  17. Ecotoxicological Serious Risk Concentrations for soil, sediment and (ground)water: updated proposals for first series of compounds. Annex

    Posthumus R; Verbruggen EMJ; CSR

    2001-01-01

    This annex is supplementary to RIVM report 711701020, 'Ecotoxicological Serious Risk Concentrations for soil, sediment and (ground)water: updated proposals for first series of compounds' (E.M.J. Verbruggen, R. Posthumus and A.P. van Wezel). For the compounds considered in this report, which were not

  18. Radionuclide activities and metal concentrations in sediments of the Sebou Estuary, NW Morocco, following a flooding event.

    Laissaoui, A; Mas, J L; Hurtado, S; Ziad, N; Villa, M; Benmansour, M

    2013-06-01

    This study presents metal concentrations (Fe, Mg, Mn, Co, Cu, Zn, Pb, As, Sr and V) and radionuclide activities ((40)K, (137)Cs, (210)Pb, (226)Ra, (228)Ac, (234)Th and (212)Pb) in surface deposits and a sediment core from the Sebou Estuary, Northwest Morocco. Samples were collected in April 2009, about 2 months after a flooding event, and analysed using a well-type coaxial gamma-ray detector and inductively coupled plasma-quadrupole mass spectrometry. Activities of radionuclides and concentrations of almost all elements in surface samples displayed only moderate spatial variation, suggesting homogenous deposition of eroded local soil in response to intense precipitation. Excess (210)Pb displayed relatively constant activity throughout the sediment core, preventing dating and precluding determination of the historical accumulation rates of pollutants at the core site. Some elements showed non-systematic trends with depth and displayed local maxima and minima. Other elements presented relatively systematic concentration trends or relatively constant levels with discrete maxima and/or minima. Except for Mn, Sr and Cr, all metal concentrations in sediment were below levels typical of polluted systems, suggesting little human impact or losses of metals from sediment particles. PMID:23054286

  19. Uranium hydrogeochemical and stream sediment reconnasissance of the Trinidad NTMS Quadrangle, Colorado, including concentrations of forty-two additional elements

    Uranium and other elemental data resulting from the Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) of the Trinidad National Topographic Map Series (NTMS) quadrangle, Colorado, by the Los Alamos Scientific Laboratory (LASL) are reported herein. This study was conducted as part of the United States Department of Energy's National Uranium Resource Evaluation (NURE), which is designed to provide improved estimates of the availability and economics of nuclear fuel resources and to make available to industry information for use in exploration and development of uranium resources. The HSSR data will ultimately be integrated with other NURE data (e.g., airborne radiometric surveys and geological investigations) to complete the entire NURE program. This report is a supplement to the HSSR uranium evaluation report for the Trinidad quadrange (Morris et al, 1978), which presented the field and uranium data for the 1060 water and 1240 sediment samples collected from 1768 locations in the quadrangle. The earlier report contains an evaluation of the uranium concentrations of the samples as well as descriptions of the geology, hydrology, climate, and uranium occurrences of the quadrange. This supplement presents the sediment field and uranium data again and the analyses of 42 other elements in the sediments. All uranium samples were redetermined by delayed-neutron counting (DNC) when the sediment samples were analyzed for 31 elements by neutron activation. For 99.6% of the sediment samples analyzed, the differences between the uranium contents first determined (Morris et al, 1978) and the analyses reported herein are less than 10%

  20. Temporal changes in concentration of radiocaesium in lake sediment and fish of southern Finland as related to environmental factors

    In 1992 the concentration of radiocaesium in the surface layer of bottom sediment of 52 lakes of southern Finland was found to have declined on average to 27.4% of 1987-88 levels and to 25.7, 28.0 and 38.6% of 1988 levels in the tissues of perch, pike and roach, respectively. The sediment radiocaesium concentration was higher in larger lakes and in lakes having a large catchment, but lower in oligotrophic than eutrophic lakes, when the total amount of electrolytes and organic matter was high. The concentration of radiocaesium in perch and pike was lower in eutrophic than oligotrophic lakes and lower in all three fish species when the concentration of electrolytes was high. Lower radiocaesium values in both sediments and fish of eutrophic when compared with oligotrophic lakes may be due to a greater dilution of this contaminant into a higher biomass. Water colour and pH were negatively correlated with radiocaesium in perch only. A lower radiocaesium level in perch in humic water lakes may be due to an adsorption of radiocaesium onto humus particles which reduces its bioavailability and transfer along the food chain. Radiocaesium in fish and in sediment were positively correlated with each other for perch and roach whose diets comprise mainly the detritivore or sediment feeding bottom animals. In perch the radiocaesium concentration was high when the water retention time of the lake was long. A tropic level bioconcentration was evident in the threefold higher radiocaesium level in predatory pike compared with roach. The decline in radiocaesium was most pronounced in sediment when the catchment area was large, when the water pH was high and when the sediment surface contained a low proportion of organic matter. In fish the largest decline in radiocaesium was recorded in pike from eutrophic or shallow lakes and when the lake water retention time was short. In perch and roach the reduced radiocaesium levels were not due to effects of water quality or lake morphometrical

  1. Influence of Dilute Acetic Acid Treatments on Survival of Monoecious Hydrilla Tubers in the Oregon House Canal, California

    Spencer, David F.; Ksander, Gregory G.

    1999-01-01

    Hydrilla (Hydrilla verticillata (L.f.)Royle), a serious aquatic weed, reproduces through formation of underground tubers. To date, attacking this life-cycle stage has been problematic. The purpose of this study was to measure the impact of exposure to dilute acetic acid on monoecious hydrilla tubers under field conditions. In this field experiment, treatments were acetic acid concentration (0, 2.5, or 5%) and sediment condition (perforated or not perforated). Each of 60, 1x1 m plots (in t...

  2. Uranium hydrogeochemical and stream sediment reconnaissance of the Arminto NTMS quadrangle, Wyoming, including concentrations of forty-three additional elements

    During the summers of 1976 and 1977, 570 water and 1249 sediment samples were collected from 1517 locations within the 18,000-km2 area of the Arminto NTMS quadrangle of central Wyoming. Water samples were collected from wells, springs, streams, and artifical ponds; sediment samples were collected from wet and dry streams, springs, and wet and dry ponds. All water samples were analyzed for 13 elements, including uranium, and each sediment sample was analyzed for 43 elements, including uranium and thorium. Uranium concentrations in water samples range from below the detection limit to 84.60 parts per billion (ppb) with a mean of 4.32 ppb. All water sample types except pond water samples were considered as a single population in interpreting the data. Pond water samples were excluded due to possible concentration of uranium by evaporation. Most of the water samples containing greater than 20 ppb uranium grouped into six clusters that indicate possible areas of interest for further investigation. One cluster is associated with the Pumpkin Buttes District, and two others are near the Kaycee and Mayoworth areas of uranium mineralization. The largest cluster is located on the west side of the Powder River Basin. One cluster is located in the central Big Horn Basin and another is in the Wind River Basin; both are in areas underlain by favorable host units. Uranium concentrations in sediment samples range from 0.08 parts per million (ppm) to 115.50 ppm with a mean of 3.50 ppm. Two clusters of sediment samples over 7 ppm were delineated. The first, containing the two highest-concentration samples, corresponds with the Copper Mountain District. Many of the high uranium concentrations in samples in this cluster may be due to contamination from mining or prospecting activity upstream from the sample sites. The second cluster encompasses a wide area in the Wind River Basin along the southern boundary of the quadrangle

  3. A multiple-state discrete-time Markov chain for estimating suspended sediment concentrations in open channel flow

    Tsai, Christina; Wu, Nai-Kuang

    2015-04-01

    In this study, transport processes of uniform size sediment particles under steady and uniform flow are described by the multi-state discrete-time Markov chain. The multi-state discrete-time Markov chain is employed to estimate the suspended sediment concentration distribution versus water depth for various steady and uniform flow conditions. Model results are validated against available measurement data and the Rouse profile. Moreover, the multi-state discrete-time Markov chain can be used to quantify the average time spent for the flow to reach the dynamic equilibrium of particle deposition and entrainment processes. In the first part of this study, suspended sediment concentration under three different flow conditions are discussed. As the Rouse number decreases, the difference between the suspended sediment concentration estimated by the Markov chain model and the Rouse profile becomes more significant, and such discrepancy can be observed at a larger relative height from the bed. It can be attributed to the fact that the use of the terminal settling velocity in the transport process can lead to underestimation of the model residence probability and overestimation of the deposition probability. In the second part, laboratory experiments are used to validate the proposed multi-state discrete-time Markov chain model. It is observed that it would take more time for the sediment concentration to reach a dynamic equilibrium as the Rouse number decreases. In addition, the flow depth is found to be a contributing factor that impacts the time spent to reach the concentration dynamic equilibrium. It is recognized that the performance of the proposed multi-state discrete-time Markov chain model relies significantly on the knowledge of the vertical distribution of the turbulence intensity.

  4. Effects of increasing temperatures on methane concentrations and methanogenesis during experimental incubation of sediments from oligotrophic and mesotrophic lakes

    Fuchs, Andrea; Lyautey, Emilie; Montuelle, Bernard; Casper, Peter

    2016-05-01

    Global warming is expected to raise temperatures in freshwater lakes, which have been acknowledged to contribute up to 10% of the atmospheric methane concentrations. Increasing temperature enhances methane production and oxidation rates, but few studies have considered the balance between both processes at experimentally higher temperatures within lake sediments. The temperature dependence of methane concentrations, methane production rates, and methanogenic (mcrA) and methanotrophic (pmoA) community size was investigated in intact sediment cores incubated with aerobic hypolimnion water at 4, 8, and 12°C over 3 weeks. Sediment cores of 25 cm length were collected at two temperate lakes—Lake Stechlin (Germany; mesotrophic-oligotrophic, maximum depth 69.5 m) and Lake Geneva (France/Switzerland; mesotrophic, maximum depth 310 m). While methane production rates in Lake Stechlin sediments did not change with increasing temperatures, methane concentrations decreased significantly. In contrast, methane production rates increased in 20-25 cm in Lake Geneva sediments with increasing temperatures, but methane concentrations did not differ. Real-time PCR demonstrated the methanogenic and methanotrophic community size remained stable independently of the incubation temperature. Methane concentrations as well as community sizes were 1-2 orders of magnitude higher in Lake Stechlin than in Lake Geneva, while potential methane production rates after 24 h were similar in both lakes, with on average 2.5 and 1.9 nmol g-1 DW h-1, respectively. Our results suggest that at higher temperatures methane oxidation could balance, and even exceed, methane production. This suggests that anaerobic methane oxidation could be involved in the methane balance at a more important rate than previously anticipated.

  5. Inoculum characterization: identification of acetate consumption routes

    García Ruiz, Javier; Flotats Ripoll, Xavier; Tey, Laura; Fernández García, Belén

    2015-01-01

    A mesophilic inoculum, likely to have syntrophic acetate oxidation bacteria (SAOB) and hydrogenotrophic methanogen (HM) activity due to operational conditions, was characterized by means of methanogenic activity tests, submitting it to different acetate and ammonia nitrogen (TAN) concentrations.

  6. Impact of seasonal variation on Escherichia coli concentrations in the riverbed sediments in the Apies River, South Africa.

    Abia, Akebe Luther King; Ubomba-Jaswa, Eunice; Momba, Maggy Ndombo Benteke

    2015-12-15

    Many South Africans living in resource-poor settings with little or no access to pipe-borne water still rely on rivers as alternative water sources for drinking and other purposes. The poor microbial quality of such water bodies calls for appropriate monitoring. However, routine monitoring only takes into consideration the microbial quality of the water column, and does not include monitoring of the riverbed sediments for microbial pollution. This study sought to investigate the microbial quality of riverbed sediments in the Apies River, Gauteng Province, South Africa, using Escherichia coli as a faecal indicator organism and to investigate the impact of seasonal variation on its abundance. Weekly samples were collected at 10 sampling sites on the Apies River between May and August 2013 (dry season) and between January and February 2014 (wet season). E. coli was enumerated using the Colilert®-18 Quanti-Tray® 2000 system. All sites tested positive for E. coli. Wastewater treatment work effluents had the highest negative impact on the river water quality. Seasonal variations had an impact on the concentration of E. coli both in water and sediments with concentrations increasing during the wet season. A strong positive correlation was observed between temperature and the E. coli concentrations. We therefore conclude that the sediments of the Apies River are heavily polluted with faecal indicator bacteria and could also harbour other microorganisms including pathogens. The release of such pathogens into the water column as a result of the resuspension of sediments due to extreme events like floods or human activities could increase the health risk of the populations using the untreated river water for recreation and other household purposes. There is therefore an urgent need to reconsider and review the current South African guidelines for water quality monitoring to include sediments, so as to protect human health and other aquatic lives. PMID:26318680

  7. Recruitment of benthic animals as a function of petroleum hydrocarbon concentrations in the sediment

    Anderson, J. W.; Riley, R. G.; Bean, R. M.

    1977-01-01

    Three separate field installations, consisting of clean and oiled sediment in fiberglass trays, were placed in the intertidal zone of Sequim Bay, Washington to determine rates of hydrocarbon depuration and recruitment of benthic organisms. Detailed chemical analysis, using glass capillary gas chromatography, and GC/MS, were conducted such that individual components and hydrocarbon classes associated with the sediment after varying periods of field depuration could be quantitated. Depuration rates of hydrocarbon types in sediment receiving oil on the surface decreased in the order of saturates, methylnaphthalenes and methylphenanthrenes. The time to 50% depuration (half-time) for these coarse sediments was approximately 100 days, while sediment mixed with oil had only decreased by about 20 to 30% by 100 days. Levels of the aromatics (naphthalenes and phenanthrenes) in the two systems followed the general pattern, but very little loss was exhibited when oil was mixed with sediment. No substantial inhibition of benthic organism recruitment was produced by either type of sediment contamination. There was a tendency for suppression of populations of mature and juvenile bivalves (Mysella tumida) at the last sampling interval for all three installations. Future sampling of these populations and further analyses of all benthic organisms may provide a better evaluation of effects of specific hydrocarbon components in sediments on benthic recruitment. These results are discussed in light of oil spill studies and other field experiments.

  8. Methane and carbon dioxide concentrations in sediments and diffusive fluxes at the sediment-water interface from three tropical systems in Brazil during the pre-impoundment phase

    Abe, D. S.; Sidagis-Galli, C.; Grimberg, D. E.; Blanco, F. D.; Rodrigues-Filho, J. L.; Tundisi, J. G.; Matsumura-Tundisi, T.; Tundisi, J. E.; Cimbleris, A. C.; Damázio, J. M.; Project Balcar

    2013-05-01

    The concentrations of methane and carbon dioxide in the sediments pore water were quantified by gas chromatography in three hydroelectric reservoirs under construction during the pre-impoundment phase. Sediment sampling was performed in ten to twelve stations in each river by a Kajak-Brinkhurst corer coupled to a 3 m long aluminum rod in four seasons. The theoretical diffusive fluxes of these gases at the sediment-water interface were also calculated using the Fick's first law of diffusion. The mean annual concentration and diffusive flux of methane were highest in the sediments of the Xingu River (12.71 ± 3.03 mmol CH4 m-2 and 3.84 ± 0.91 mmol CH4 m-2 d-1), located in the Amazon, influenced by the presence of organic matter originating from the surrounding forest. The mean annual concentration of carbon dioxide was highest in the São Marcos River (71.36 ± 10.36 mmol CO2 m-2), located in an area of cerrado savanna, while the highest diffusive flux of carbon dioxide was observed in the Madeira River (30.23 ± 2.41 mmol CO2 m-2 d-1), which rises in the Andes Cordillera and has a very high water flow. The mean concentration and diffusive flux of carbon dioxide in the three studied systems were much higher (64-98%) in comparison with the methane, influenced by the oxic condition in these lotic systems. Nevertheless, the present study shows that the sediments of these systems, especially in the Xingu River, have significant amount of methane dissolved in the pore water which is being diffused to the overlying water. The information obtained in this study during the pre-filling phase will be important for the calculation of net flows of greenhouse gases after the impoundment of these future reservoirs. This study is part of the Strategic Project "Monitoring Emissions of Greenhouse Gases in Hydroelectric Reservoirs" - Call 099/2008 of the Brazilian Agency of Electric Energy (ANEEL) and sponsored by ELETRONORTE, FURNAS and CHESF.

  9. Dynamic Model Of Suspended Sediment Concentration River Discharge And Rainfall Intensity At Padang Watershed North Sumatra Indonesia

    Kemala Sari Lubis

    2015-07-01

    Full Text Available Abstract Sediment transport has relationship with hydrologic input primarily river discharge and rainfall intensity. Fluctuation of river discharge and rainfall intensity have great effect on suspended sediment concentration. Bayesian Dynamic Linear Model DLMs is used to study relation of input hydrology and basin response variables. Response variables were taken from suspended sediment concentration and river discharge from a year July 2012 to June 2013 at two outlets at Padang sub-watershed upstream and Padang Hilir sub-watershed downstream of Padang watershed North Sumatra. Datas were analyzed by regression analysis of Suspended Sediment Concentration SSC as a dependent variables while river discharge and rainfall intensity as independent variables. The results showed that river discharge value are the highest on July 2012 and October 2012 at upstream and downstream of Padang watershed respectively. The SSC value are the highest on July 2012 and April 2013 at upstream and downstream of Padang watershed respectively. There is a weak correlation r2 0.002 between SSC and rainfall intensity at source points of outlet at upstream of Padang watershed. There is decreasing of forest paddy and plantation areas but increasing of bush and farming areas from 2012 to 2015 at upstream of Padang watershed. Meanwhile at downstream of Padang watershed were increasing of plantation areas since 2012 to 2015

  10. Bioavailability of PAHs in aluminum smelter affected sediments: evaluation through assessment of pore water concentrations and in vivo bioaccumulation.

    Ruus, Anders; Bøyum, Olav; Grung, Merete; Næs, Kristoffer

    2010-12-15

    Bioaccumulation of polycyclic aromatic hydrocarbons (PAHs) from coal tar pitch polluted sediments was predicted by (1) a generic approach based on organic carbon-water partitioning and Gibbs linear free energy relationship (between K(OW) and K(OC)), and (2) measurements of freely dissolved concentrations of PAHs in the sediment pore water, using passive samplers and solid phase extraction. Results from these predictions were compared with those from in vivo bioaccumulation experiments using Nereis diversicolor (Polychaeta), Hinia reticulata (Gastropoda), and Nuculoma tenuis (Bivalvia). Measured sediment/water partition coefficients were higher than predicted by the generic approach. Furthermore, predicted biota-to-sediment accumulation factors (BSAFs) derived from measured pore water concentrations were more in agreement with the bioaccumulation observed for two of the three species. Discrepancies associated with the third species (N. tenuis) were likely a result of particles remaining in the intestine (as shown by microscopic evaluation). These results indicate the importance of conducting site-specific evaluations of pore water concentrations and/or bioaccumulation studies by direct measurements to accurately provide a basis for risk assessment and remediation plans. The importance of knowledge regarding specific characteristics of model organisms is emphasized. PMID:21077669

  11. Influence of land use on metal concentrations in playa sediments and amphibians in the Southern High Plains

    The Southern High Plains (SHP) is a semi-arid region in which playa wetlands are the focal points of biodiversity. Playas are highly influenced by surrounding land use. Most of the SHP is in agricultural production (primarily cotton) with a history of arsenic-containing herbicide use. Metals influence reproduction and development in amphibians. We analyzed metal residues in playa sediment and whole body tissue of Spea spp. and Bufo cognatus metamorphs from two land uses: cropland and native grassland. Cd and Ni concentrations in B. cognatus tissues differed between land uses. Metal concentrations in Spea spp. tissues did not differ between land uses. Ba was higher in Spea spp. than B. cognatus collected from the same grassland playas, indicating differential habitat use. No correlations between sediment and tissue concentrations were found. Land use appeared to have little influence on metal concentrations and levels were below those known to cause effects in amphibians. - Land use surrounding playas has little effect on metal concentrations in sediments

  12. Preparation of a novel PAN/cellulose acetate-Ag based activated carbon nanofiber and its adsorption performance for low-concentration SO2

    Wu, Yan-bo; Bi, Jun; Lou, Ting; Song, Tie-ben; Yu, Hong-quan

    2015-04-01

    Polyacrylonitrile (PAN), PAN/cellulose acetate (CA), and PAN/CA-Ag based activated carbon nanofiber (ACNF) were prepared using electrostatic spinning and further heat treatment. Thermogravimetry-differential scanning calorimetry (TG-DSC) analysis indicated that the addition of CA or Ag did not have a significant impact on the thermal decomposition of PAN materials but the yields of fibers could be improved. Scanning electron microscopy (SEM) analysis showed that the micromorphologies of produced fibers were greatly influenced by the viscosity and conductivity of precursor solutions. Fourier transform infrared spectroscopy (FT-IR) analysis proved that a cyclized or trapezoidal structure could form and the carbon scaffold composed of C=C bonds appeared in the PAN-based ACNFs. The characteristic diffraction peaks in X-ray diffraction (XRD) spectra were the evidence of a turbostratic structure and silver existed in the PAN/CA-Ag based ACNF. Brunner-Emmett-Teller (BET) analysis showed that the doping of CA and Ag increased surface area and micropore volume of fibers; particularly, PAN/CA-Ag based ACNF exhibited the best porosity feature. Furthermore, SO2 adsorption experiments indicated that all the three fibers had good adsorption effects on lower concentrations of SO2 at room temperature; especially, the PAN/CA-Ag based ACNF showed the best adsorption performance, and it may be one of the most promising adsorbents used in the fields of chemical industry and environment protection.

  13. The use of deuterated ethyl acetate in highly concentrated electrolyte as a low-cost solvent for in situ neutron diffraction measurements of Li-ion battery electrodes

    A low-cost deuterated electrolyte suitable for in situ neutron diffraction measurements of normal and high voltage Li-ion battery electrodes is reported here. Li[Ni0.4Mn0.4Co0.2]O2/graphite (NMC(442)/graphite) pouch cells filled with 1:0.1:2 (molar ratio) of lithium bis(fluorosulfonyl) imide (LiFSi):LiPF6: ethyl acetate (EA) and LiFSi:LiPF6:deuterated EA (d8-EA) electrolytes were successfully cycled between 2.8 V and 4.7 V at 40°C for 250 h without significant capacity loss, polarization growth, or gas production. The signal-to-noise ratio of neutron powder diffraction patterns taken on NMC(442) powder with a conventional deuterated organic carbonate-based electrolyte and filled with LiFSi:LiPF6:d8-EA electrolyte were virtually identical. Out of all the solvents widely available in deuterated form tested in highly-concentrated systems, EA was the only one providing a good balance between cost and charge-discharge capacity retention to 4.7 V. The use of such an electrolyte blend would half the cost of deuterated solvents needed for in situ neutron diffraction measurements of Li-ion batteries compared to conventional deuterated carbonate-based electrolytes

  14. Effect of oxalic acid treatment on sediment arsenic concentrations and lability under reducing conditions.

    Sun, Jing; Bostick, Benjamin C; Mailloux, Brian J; Ross, James M; Chillrud, Steven N

    2016-07-01

    Oxalic acid enhances arsenic (As) mobilization by dissolving As host minerals and competing for sorption sites. Oxalic acid amendments thus could potentially improve the efficiency of widely used pump-and-treat (P&T) remediation. This study investigates the effectiveness of oxalic acid on As mobilization from contaminated sediments with different As input sources and redox conditions, and examines whether residual sediment As after oxalic acid treatment can still be reductively mobilized. Batch extraction, column, and microcosm experiments were performed in the laboratory using sediments from the Dover Municipal Landfill and the Vineland Chemical Company Superfund sites. Oxalic acid mobilized As from both Dover and Vineland sediments, although the efficiency rates were different. The residual As in both Dover and Vineland sediments after oxalic acid treatment was less vulnerable to microbial reduction than before the treatment. Oxalic acid could thus improve the efficiency of P&T. X-ray absorption spectroscopy analysis indicated that the Vineland sediment samples still contained reactive Fe(III) minerals after oxalic acid treatment, and thus released more As into solution under reducing conditions than the treated Dover samples. Therefore, the efficacy of enhanced P&T must consider sediment Fe mineralogy when evaluating its overall potential for remediating groundwater As. PMID:26970042

  15. The effects of varying concentrations of growth regulators benzyladenine and naphthalene acetic acid and gamma irradiation on the gross plantlet morphology of Garcinia mangostana L

    Mangosteen (Garcinia mangostana L.) is regarded as one of the best flavored fruits in the world. Though this fruit yields high income and has great potential as an export, productivity in the Philippines is still limited due to its slow and difficult conventional propagation. To increase the plants' productivity, growth regulators can be added, the seeds can be exposed to irradiation to cause genetic mutations, and micropropagation techniques can be used. This study seeks to determine the effects of these three variables on the general morphological characteristics of the plantlets grown both in vitro and in vivo. The first set of mangosteen seeds was inoculated and grown in Murashige and Skoog (MS) basal culture medium with different treatment combinations of growth regulators, naphthalene acetic acid (NAA) and benzyladenine (BA). Treatment concentrations ranged from 0 parts per million (ppm) to 6 ppm. The treatment that best induced stem, leaf and root formation, and produced plantlets with long stems and roots was MS with 6 ppm NAA combined with 6 ppm BA. A second set of seeds was then exposed to varying levels of gamma radiation and propagated in vivo and in vitro. For in vivo, it was observed that the length of stem of the plantlet decreases with increasing radiation dose; length of leaves of the mangosteen plantlets was best noted in seeds exposed to 10 Gy gamma rays. In in vitro, the two treatment concentrations that best helped seeds to develop callus, which were 0 ppm BA with 4 pmm NAA and 4 ppm BA with 6 ppm NAA, were added to MS basal medium. Seeds exposed to 5 Gy and grown in basal medium with 0 ppm BA and 4 ppm NAA were observed to have developed the most callus. (Author)

  16. Petroleum hydrocarbon concentration in sediments along northern west coast of India

    Ram, A.; Kadam, A.N.

    Gas chromatography revealed that nonpolar material extracted from surface sediments collected along the northern west coast of India was originated from petroleum hydrocarbon residue. Petroleum hydrocarbon levels as determinEd. by fluorescence...

  17. Alaska Geochemical Database (AGDB)-Geochemical data for rock, sediment, soil, mineral, and concentrate sample media

    Granitto, Matthew; Bailey, Elizabeth A.; Schmidt, Jeanine M.; Shew, Nora B.; Gamble, Bruce M.; Labay, Keith A.

    2011-01-01

    The Alaska Geochemical Database (AGDB) was created and designed to compile and integrate geochemical data from Alaska in order to facilitate geologic mapping, petrologic studies, mineral resource assessments, definition of geochemical baseline values and statistics, environmental impact assessments, and studies in medical geology. This Microsoft Access database serves as a data archive in support of present and future Alaskan geologic and geochemical projects, and contains data tables describing historical and new quantitative and qualitative geochemical analyses. The analytical results were determined by 85 laboratory and field analytical methods on 264,095 rock, sediment, soil, mineral and heavy-mineral concentrate samples. Most samples were collected by U.S. Geological Survey (USGS) personnel and analyzed in USGS laboratories or, under contracts, in commercial analytical laboratories. These data represent analyses of samples collected as part of various USGS programs and projects from 1962 to 2009. In addition, mineralogical data from 18,138 nonmagnetic heavy mineral concentrate samples are included in this database. The AGDB includes historical geochemical data originally archived in the USGS Rock Analysis Storage System (RASS) database, used from the mid-1960s through the late 1980s and the USGS PLUTO database used from the mid-1970s through the mid-1990s. All of these data are currently maintained in the Oracle-based National Geochemical Database (NGDB). Retrievals from the NGDB were used to generate most of the AGDB data set. These data were checked for accuracy regarding sample location, sample media type, and analytical methods used. This arduous process of reviewing, verifying and, where necessary, editing all USGS geochemical data resulted in a significantly improved Alaska geochemical dataset. USGS data that were not previously in the NGDB because the data predate the earliest USGS geochemical databases, or were once excluded for programmatic reasons

  18. Spatial Evaluation of Heavy Metals Concentrations in the Surface Sediment of Taihu Lake

    Yong Niu; Wei Jiao; Hui Yu; Yuan Niu; Yong Pang; Xiangyang Xu; Xiaochun Guo

    2015-01-01

    With regard to the size of China’s freshwater lakes, Taihu Lake ranks third and it plays an important role in the supply of drinking water, flood prevention, farming and navigation, as well as in the travelling industry. The problem of environmental pollution has attracted widespread attention in recent years. In order to understand the levels, distribution and sources of heavy metals in sediments of Taihu Lake, random selection was carried out to obtain 59 samples of surface sediment from th...

  19. Measurements of radiocarbon concentrations by accelerator mass spectrometry in the bottom sediments from Lake Tilitso in Nepal, Himalayas

    Concentrations of radionuclides such as14C, 137Cs, 210Pb, and 214Pb, the contents of organic C and N, and 13C/12C ratios were measured for near surface sediments collected from Tilitso, a high altitude lake in Nepal, Himalayas, Living attached algae obtained from the streams feeding Lake Tilitso were also analyzed on their 14C abundances. The 14C concentration Δ14C, was measured by direct detection of 14C atoms using a Tandetron accelerator mass spectrometer, on the acid-insoluble organic carbon that was extracetd from each sediment or each algae sample. Activities of 137Cs, 210Pb, and 214Pb in the sediments were measured with a coaxial-well-type high-purity-germanium detector. The sedimentation rate was estimated to be 0.56±0.27 cm y-1 by the 210Pb method. The content of carbon as acid-insoluble organic compounds was from 0.5 to 0.7%, and such carbon was depleted in 14C, yielding Δ14C values between -855±5 and -905±4mil (apparent 14C ages between 15,520±250 and 18,910±360 y BP). Values of Δ14C for attached algae samples were also low, ranging from -463±31 to -701±29mil (apparent ages from 4,980±460 to 9,700±780 y BP). The unexpectedly low 14C concentrations of these sediment and attached algae samples can be reasonably explained by considering geological and climatic environments around Lake Tilitso. (author)

  20. Intratidal and neap-spring variations of suspended sediment concentrations and sediment transport processes in the North Branch of the Changjiang Estuary

    LI Zhanhai; LI Michael Z; DAI Zhijun; ZHAO Fangfang; LI Jiufa

    2015-01-01

    Profiles of tidal current and suspended sediment concentration (SSC) were measured in the North Branch of the Changjiang Estuary from neap tide to spring tide in April 2010. The measurement data were analyzed to determine the characteristics of intratidal and neap-spring variations of SSC and suspended sediment transport. Modulated by tidal range and current speed, the tidal mean SSC increased from 0.5 kg/m3in neap tide to 3.5 kg/m3 in spring tide. The intratidal variation of the depth-mean SSC can be summarized into three types: V-shape variation in neap tide, M-shape and mixed M-V shape variation in medium and spring tides. The occurrence of these variation types is controlled by the relative intensity and interaction of resuspension, settling and impact of water exchange from the rise and fall of tide. In neap tide the V-shape variation is mainly due to the dominant effect of the water exchange from the rise and fall of tide. During medium and spring tides, resuspension and settling processes become dominant. The interactions of these processes, together with the sustained high ebb current and shorter duration of low-tide slack, are respon-sible for the M-shape and M-V shape SSC variation. Weakly consolidated mud and high current speed cause significant resuspension and remarkable flood and ebb SSC peaks. Settling occurs at the slack water periods to cause SSC troughs and formation of a thin fluff layer on the bed. Fluxes of water and suspended sediment averaged over the neap-spring cycle are all seawards, but the magnitude and direction of tidal net sediment flux is highly variable.

  1. Incipient motion of surf zone sediments

    Frank, Donya; Foster, Diane; Sou, In Mei; Calantoni, Joseph

    2015-08-01

    Incipient motion experiments were conducted with natural gravel, acetate beads, and coarse-gravel-sized electronic grains called Smart Sediment Grains in a Small-Oscillatory Flow Tunnel. Measurements of fluid velocity were made using Particle Image Velocimetry. The strength of the fluid shear stresses and the pressure gradients were examined for a range of oscillatory flow conditions at the onset of motion of the sediment particles to determine which mechanism had induced particle motion. The three sediment types utilized in these experiments facilitated an assessment of the effects of sediment grain size diameter, shape, and density on incipient motion. Results suggested that the onset of sediment motion was dominated by the pressure gradients for flows with small orbital excursion amplitudes, by the shear stresses for flows with large orbital excursion amplitudes and by the combined effects for intermediate flows. The denser, angular gravel required greater free-stream accelerations to trigger sediment motion than the spherical, less dense acetate beads, and Smart Sediment Grains. A combined parameter for incipient motion that accounts for the simultaneous effects of both shear stresses and pressure gradients while depending on the static coefficient of friction and the packing concentration of the mobile bed layer was evaluated for accuracy using a range of sediment types. The results suggested that the combined parameter may be a better indicator of sediment mobilization under oscillatory flows than the typically assumed shear stress criterion.

  2. Dioxin concentrations in sediments of the Baltic Sea. A preliminary survey of existing data

    Verta, M.; Salo, S.; Korhonen, M. [Finnish Environment Institute, Helsinki (Finland); Kiviranta, H. [National Public Health Institute, Helsinki (Finland); Koistinen, J.; Ruokojaervi, P.; Isosaari, P. [National Public Health Institute, Kuopio (Finland)

    2004-09-15

    The Baltic Sea region is one of the most contaminated areas with persistent organic pollutants (POPs) including polychlorinated dibenzo-p-dioxins and dibenzofurans (dioxins). The high load of dioxins in Baltic fish has lead to restrictions of the use of contaminated fish for human consumption. Uncertainties about sources, geographical distribution of these contaminants, the pathways of bioaccumulation and possible ecotoxicological and human health effects are of concern. POPs may enter the Baltic Sea from atmospheric deposition, riverine input and point sources along the coast. The ultimate sink for the majority of the compounds is the open sea and coastal sediments, although some fraction enters the food chain. Analysis of sediment has been widely used to study regional and temporal trends of dioxin pollution in freshwater and oceans and the Baltic Sea has been one of the most studied sea areas for dioxin-like compounds as well. Only a fraction (unknown) of the analytical results have been published in scientific papers, however. Here we present regional distribution of certain congeners of dioxins in surface sediments and in six sediment cores from the Baltic Sea. New data is compared with data on earlier Finnish sediment surveys. Some data from published papers and unpublished data from the Kattegat Sound is also given for reference. The purpose of this paper is to: 1. get an ''draft'' picture of regional distribution (possible hot spots, major regional differences) along the Finnish-Swedish-Danish-German coastal and open sea sites in the Baltic 2. study differences in congener distributions (source identification) 3. study temporal changes in sediment profiles 4. identify major areas with gap of data 5. call for more data (both published and grey literature as well as new sediment surveys)

  3. Concentration Levels and Ecological Risks of Persistent Organic Pollutants in the Surface Sediments of Tianjin Coastal Area, China

    Xiaoxia Lu; Chaoqi Chen; Shu Zhang; Zhen Hou; Junjun Yang

    2013-01-01

    Sediments were sampled from different surface water bodies in Tianjin coastal area, China, and persistent organic pollutants (POPs) including polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) were measured using GC/MS or GC/ECD. The purposes were to investigate the concentration levels of the POPs and to assess their ecological risks. The results showed that all the 16 priority PAHs were dete...

  4. Vitamin B1 in marine sediments: pore water concentration gradient drives benthic flux with potential biological implications

    Monteverde, Danielle R.; Gómez-Consarnau, Laura; Cutter, Lynda; Chong, Lauren; Berelson, William; Sañudo-Wilhelmy, Sergio A.

    2015-01-01

    Vitamin B1, or thiamin, can limit primary productivity in marine environments, however the major marine environmental sources of this essential coenzyme remain largely unknown. Vitamin B1 can only be produced by organisms that possess its complete synthesis pathway, while other organisms meet their cellular B1 quota by scavenging the coenzyme from exogenous sources. Due to high bacterial cell density and diversity, marine sediments could represent some of the highest concentrations of putativ...

  5. Non-stationary Concentration-Discharge Relationships for Nitrogen, Phosphorus, and Sediment for Nine Major Tributaries of the Chesapeake Bay

    Zhang, Q.; Ball, W. P.

    2015-12-01

    Derived from river water-quality monitoring data, concentration-discharge (C-Q) relationships are a powerful tool for understanding nutrient and sediment dynamics. Here we first present a brief review of C-Q relationships documented in the scientific literature. Major categories of observed relationships for nutrient and sediment include: (a) "dilution" patterns (i.e., negative C-Q relationships), particularly for point-source dominated rivers; and (b) "concentration" patterns (i.e., positive C-Q relationships), particularly for nonpoint-source dominated rivers. In the second part of our work, we present a comprehensive evaluation of riverine C-Q patterns for multiple water-quality constituents for the nine major non-tidal tributaries of the Chesapeake Bay. Specifically, we have analyzed concentration data sets of total nitrogen, nitrate plus nitrite, total phosphorus, dissolved orthophosphate, and suspended sediment for the period between the 1980s and 2015. Separation of the monitoring data into non-overlapping decadal periods revealed clear non-stationarity in C-Q relationships for many of the selected site-constituent combinations. These temporal changes in C-Q relationships generally reflected changes in dominant watershed sources of nutrients and sediment (e.g., reduction in point-source dominance for total nitrogen in the Patuxent River due to technology upgrade at wastewater treatment plants) and are consistent with trends observed in previous research. The findings also highlight the potential pitfalls of assuming stationary C-Q relationships when estimating riverine concentrations and fluxes or analyzing their trends.

  6. Response of suspended sediment concentration to tidal dynamics at a site inside the mouth of an inlet: Jiaozhou Bay (China

    S. L. Yang

    2004-01-01

    Full Text Available Observations of fair weather currents and suspended sediment concentrations (SSC were made using an acoustic Doppler current profiler and two YSI turbidity sensors over a neap to spring time cycle at a site near the inner mouth of a semi-enclosed mesotidal-macrotidal embayment (Jiaozhou Bay to examine the influence of tidal dynamics on concentration and transport of suspended sediment. During the investigation, SSC varied from about 3 to 16 mg L–1 at the surface and about 6 to 40 mg L–1 close to the bed, while the current velocity reached 79 cm s–1 at the surface and 61 cm s–1 near the bed. SSC was tidally cyclic. The near-bed instantaneous SSC was closely related to current velocity with almost no time lag, indicating that the variability of SSC was governed by current-induced settling/resuspension. At the surface, however, instantaneous SSC was poorly related to instantaneous current velocity because the peak SSC tended to occur around ebb slack water. This suggests that the surface SSC was controlled by horizontal advection from landward higher concentration areas. Both at the surface and near the bed, on the other hand, tidally-averaged SSC was well correlated to tidal range and current speed. Current velocity and SSC were flood-dominated for all the tides investigated, which resulted in significant landward residual suspended sediment transport at the study site. The observed flood dominance was mainly attributed to the location of the study site on the landward side of the bay’s inlet where flow separation is favoured during flood tide. It was concluded that tides are the dominant hydrodynamic component controlling the variability of SSC during fair weather at the study area. Keywords: sediment, concentration, suspension, advection, currents, shoalling effect, Jiaozhou Bay, China

  7. Concentration, distribution, and comparison of selected trace elements in bed sediment and fish tissue in the South Platte River Basin, USA, 1992-1993.

    Heiny, J S; Tate, C M

    1997-04-01

    During August-November 1992 and August 1993, bed sediment and fish liver were sampled in the South Platte River Basin and analyzed for 45 elements in bed sediment and 19 elements in fish liver. The results for aluminum, arsenic, cadmium, chromium, copper, iron, lead,manganese, selenium, silver, uranium, and zinc are presented here. All 12 trace elements were detected in bed sediment, but not all were detected in fish liver or in all species of fish. A background concentration of trace elements in bed sediment was calculated using the cumulative frequency curves of trace element concentrations at all sites. Arsenic, cadmium, copper, lead, manganese, silver, uranium, and zinc concentrations were greater than background concentrations at sites in mining areas or at sites that have natural sources of these elements. Trace element concentrations in fish liver generally did not follow the same patterns as concentrations in bed sediment, although concentrations of aluminum and cadmium were higher in fish liver collected at mountain sites that had been disturbed by mining. Concentrations of aluminum, arsenic, cadmium, chromium, copper, iron, lead, silver, and zinc increased in bed sediments in urban areas. Iron, silver, and zinc concentrations in fish liver also increased in urban areas. Concentrations of cadmium, copper, silver, and zinc in fish liver increased in the agricultural areas of the basin. Downstream changes in trace element concentrations may be the result of geological changes in addition to changes in land use along the river. PMID:9096073

  8. A data reconnaissance on the effect of suspended-sediment concentrations on dissolved-solids concentrations in rivers and tributaries in the Upper Colorado River Basin

    Tillman, Fred D; Anning, David W.

    2014-01-01

    The Colorado River is one of the most important sources of water in the western United States, supplying water to over 35 million people in the U.S. and 3 million people in Mexico. High dissolved-solids loading to the River and tributaries are derived primarily from geologic material deposited in inland seas in the mid-to-late Cretaceous Period, but this loading may be increased by human activities. High dissolved solids in the River causes substantial damages to users, primarily in reduced agricultural crop yields and corrosion. The Colorado River Basin Salinity Control Program was created to manage dissolved-solids loading to the River and has focused primarily on reducing irrigation-related loading from agricultural areas. This work presents a reconnaissance of existing data from sites in the Upper Colorado River Basin (UCRB) in order to highlight areas where suspended-sediment control measures may be useful in reducing dissolved-solids concentrations. Multiple linear regression was used on data from 164 sites in the UCRB to develop dissolved-solids models that include combinations of explanatory variables of suspended sediment, flow, and time. Results from the partial t-test, overall likelihood ratio, and partial likelihood ratio on the models were used to group the sites into categories of strong, moderate, weak, and no-evidence of a relation between suspended-sediment and dissolved-solids concentrations. Results show 68 sites have strong or moderate evidence of a relation, with drainage areas for many of these sites composed of a large percentage of clastic sedimentary rocks. These results could assist water managers in the region in directing field-scale evaluation of suspended-sediment control measures to reduce UCRB dissolved-solids loading.

  9. Uranium hydrogeochemical and stream sediment reconnaissance of the thermopolis NTMS Quadrangle, Wyoming, including concentrations of forty-two additional elements

    The Los Alamos Scientific Laboratory conducted a hydrogeochemical and stream sediment reconnaissance for uranium in the Thermopolis National Topographic Map Series quadrangle, Wyoming. Totals of 920 water and 1821 sediment samples were collected from 1977 locations at an average density of one sample location per 9 km2 over an 18,000-km2 area. Water samples were collected from streams, springs, and wells; sediment samples were collected from streams and springs. The uranium contents of water samples range from below the detection limit of 0.02 ppB to 307.98 ppB with a median of 0.56 ppB. Six clusters of anomalous water samples were delineated within the Wind River Basin and are associated predominantly with the Wind River formation. Two clusters of anomalous waters were collected on the southern margin of the Bighorn Basin and are associated with sandstone and shales of Permian through Cretaceous age. The uranium contents of sediment samples range from 0.43 to 94.65 ppM with a median of 2.90 ppM. Most sediment samples with uranium concentrations of greater than 12 ppM are underlain by Precambrian crystalline rocks of the Wind River Range; this area contains the highest uranium values found in sediments from the Thermopolis quadrangle. Other samples containing greater than 12 ppM uranium are found associated with the Wind River and Aycross formations along the northern margin of the Wind River Basin, and one sample was collected from Precambrian granitic terrain of the Owl Creek Mountains

  10. Estimating mercury concentrations and fluxes in the water column and sediment of Lake Ontario with HERMES model

    The HERMES model-predicted Hg concentrations and fluxes in Lake Ontario were based on twelve lake and drainage basin variables (i.e., water temperature, precipitation rate, air Hg, surface area, mean depth, water volume, water inflow rate, inflow water Hg, inflow and lake suspended particulate matter, air–water and water–air mass transfer coefficients, and sedimentation rate). The HERMES model-predicted Hg water and surface sediment concentrations were found to be significantly correlated (±20%) with measured values (r2 = 0.94, p 2 = 0.95, p 2) lakes in Nova Scotia and Ontario, Canada (i.e., water and sediment Hg concentrations were ±15% of measured data). Results suggest that HERMES could be applicable to a broad range of lake sizes. Uncertainty analyses on HERMES model input variables indicated a larger atmospheric Hg contribution for Lake Ontario when compared to previous predictions for smaller lakes. - Highlights: ► A screening-level Hg model (HERMES) was evaluated on a large urban lake. ► HERMES was significantly (p < 0.0001) correlated with measured values. ► HERMES was significantly (p < 0.0001) correlated with predicted LOTOX2-Hg values. ► HERMES shows larger atmospheric Hg input then previously studied smaller lakes. - Evaluation of a screening-level Hg model (HERMES) on a large well-studied urban lake (Lake Ontario).

  11. Effects of season and altitude on copper and zinc concentrations in benthos (Chironomids and Gammarids and sediment

    Arash Javanshir

    2013-04-01

    Full Text Available Concentration of heavy metals in aquatic ecosystems is considered as an important environmantal issue. In this study, the Namrood River located in Firoozkooh (Tehran province, Iran was assessed for the existence of heavy metals. The Namrood river is situated by the main road being by pollutants from tourism and recreational centers, gas stations, sewage of villages, agricultural wastewater and fish culture effluent. The water is extremely contaminated in some parts and possibly contains heavy metals. In the present study, two stations up- and downstream were determined to sample the sediments and Chironomidae and Gammarus pluex in both cold and warm seasons of the year (middle of March and middle of August. The copper and zinc were measured in sediment and benthos. The results showed that copper and zinc concentrations ranged 0.170-0.966 and 0.187-3.846 ppm, respectively. Sediments of the upstream station had the highest copper concentration among the samples in both cold and warm seasons of the year.

  12. Temporal variations of 90Sr and 137Cs concentrations in Japanese coastal surface seawater and sediments from 1974 to 1998

    Ikeuchi, Yoshihiro

    2003-09-01

    90Sr and 137Cs concentrations were determined in surface water and bottom sediments collected at 11 sites offshore from Japan during the period 1974-1998, to investigate their temporal variations and behaviour in the coastal marine environment. The concentrations of 90Sr and 137Cs in surface water have decreased with time since 1974. After the period of atmospheric nuclear weapons tests, the mean residence times of 90Sr and 137Cs were about 41 and 51 years, respectively. The 137Cs/ 90Sr activity ratios in coastal seawater during the atmospheric nuclear weapons tests (up until 1980) were lower than those after the tests due to the inflow of 90Sr in river water. A sharp increase in 137Cs levels was observed in airborne dust, in precipitation on the Japanese islands, and in coastal surface seawater in 1986 following the Chernobyl accident. However, the 137Cs levels in surface water returned to pre-1986 levels quickly, indicating rapid removal of Cs from the surface to deeper water. Concentrations of 90Sr in sediments were generally much lower than those for 137Cs, reflecting the more effective scavenging of Cs from the water column. In Ca-rich sediments, consisting of corals and shells, higher 90Sr levels and 90Sr/ 137Cs activity ratios were found, reflecting higher accumulation of Sr than Cs in marine organisms. Higher accumulation of 90Sr than 137Cs was also found in seaweed (gulfweed and wakame).

  13. Estimating mercury concentrations and fluxes in the water column and sediment of Lake Ontario with HERMES model.

    Ethier, Adrienne L M; Atkinson, Joseph F; Depinto, Joseph V; Lean, David R S

    2012-02-01

    The HERMES model-predicted Hg concentrations and fluxes in Lake Ontario were based on twelve lake and drainage basin variables (i.e., water temperature, precipitation rate, air Hg, surface area, mean depth, water volume, water inflow rate, inflow water Hg, inflow and lake suspended particulate matter, air-water and water-air mass transfer coefficients, and sedimentation rate). The HERMES model-predicted Hg water and surface sediment concentrations were found to be significantly correlated (±20%) with measured values (r(2) = 0.94, p < 0.0001, n = 13) and mechanistic model predictions (LOTOX2-Hg, r(2) = 0.95, p < 0.0001, n = 10). The predictive capacity of HERMES was previously tested on smaller (≤1 km(2)) lakes in Nova Scotia and Ontario, Canada (i.e., water and sediment Hg concentrations were ±15% of measured data). Results suggest that HERMES could be applicable to a broad range of lake sizes. Uncertainty analyses on HERMES model input variables indicated a larger atmospheric Hg contribution for Lake Ontario when compared to previous predictions for smaller lakes. PMID:21726924

  14. Combined use of remote sensing and continuous monitoring to analyse the variability of suspended-sediment concentrations in San Francisco Bay, California

    Ruhl, C.A.; Schoellhamer, D.H.; Stumpf, R.P.; Lindsay, C.L.

    2001-01-01

    Analysis of suspended-sediment concentration data in San Francisco Bay is complicated by spatial and temporal variability. In situ optical backscatterance sensors provide continuous suspended-sediment concentration data, but inaccessibility, vandalism, and cost limit the number of potential monitoring stations. Satellite imagery reveals the spatial distribution of surficial-suspended sediment concentrations in the Bay; however, temporal resolution is poor. Analysis of the in situ sensor data in conjunction with the satellite reflectance data shows the effects of physical processes on both the spatial and temporal distribution of suspended sediment in San Francisco Bay. Plumes can be created by large freshwater flows. Zones of high suspended-sediment concentrations in shallow subembayments are associated with wind-wave resuspension and the spring-neap cycle. Filaments of clear and turbid water are caused by different transport processes in deep channels, as opposed to adjacent shallow water.

  15. Seasonal and Spatial Variability in Lake Michigan Sediment Small-Subunit rRNA Concentrations

    MacGregor, Barbara J.; Moser, Duane P.; Baker, Brett J.; Alm, Elizabeth W.; Maurer, Max; Nealson, Kenneth H.; Stahl, David A.

    2001-01-01

    We have used molecular biological methods to study the distribution of microbial small-subunit rRNAs (SSU rRNAs), in relation to chemical profiles, in offshore Lake Michigan sediments. The sampling site is at a depth of 100 m, with temperatures of 2 to 4°C year-round. RNA extracted from sediment was probed with radiolabeled oligonucleotides targeting bacterial, archaeal, and eukaryotic SSU rRNAs, as well as with a universal probe. The coverage of these probes in relation to the present sequen...

  16. Estimating concentrations of fine-grained and total suspended sediment from close-range remote sensing imagery

    Mosbrucker, Adam; Spicer, Kurt R.; Christianson, Tami; Uhrich, Mark A.

    2015-01-01

    Fluvial sediment, a vital surface water resource, is hazardous in excess. Suspended sediment, the most prevalent source of impairment of river systems, can adversely affect flood control, navigation, fisheries and aquatic ecosystems, recreation, and water supply (e.g., Rasmussen et al., 2009; Qu, 2014). Monitoring programs typically focus on suspended-sediment concentration (SSC) and discharge (SSQ). These time-series data are used to study changes to basin hydrology, geomorphology, and ecology caused by disturbances. The U.S. Geological Survey (USGS) has traditionally used physical sediment sample-based methods (Edwards and Glysson, 1999; Nolan et al., 2005; Gray et al., 2008) to compute SSC and SSQ from continuous streamflow data using a sediment transport-curve (e.g., Walling, 1977) or hydrologic interpretation (Porterfield, 1972). Accuracy of these data is typically constrained by the resources required to collect and analyze intermittent physical samples. Quantifying SSC using continuous instream turbidity is rapidly becoming common practice among sediment monitoring programs. Estimations of SSC and SSQ are modeled from linear regression analysis of concurrent turbidity and physical samples. Sediment-surrogate technologies such as turbidity promise near real-time information, increased accuracy, and reduced cost compared to traditional physical sample-based methods (Walling, 1977; Uhrich and Bragg, 2003; Gray and Gartner, 2009; Rasmussen et al., 2009; Landers et al., 2012; Landers and Sturm, 2013; Uhrich et al., 2014). Statistical comparisons among SSQ computation methods show that turbidity-SSC regression models can have much less uncertainty than streamflow-based sediment transport-curves or hydrologic interpretation (Walling, 1977; Lewis, 1996; Glysson et al., 2001; Lee et al., 2008). However, computation of SSC and SSQ records from continuous instream turbidity data is not without challenges; some of these include environmental fouling, calibration, and

  17. Impacts of anthropic pressures on soil phosphorus availability, concentration, and phosphorus forms in sediments in a Southern Brazilian watershed

    Pellegrini, Joao Batista Rossetto; Rheinheimer dos Santos, Danilo; Goncalves, Celso Santos; Copetti, Andre Carlos Cruz [Dept. de Solos, Univ. Federal de Santa Maria, Centro de Ciencias Rurais, Santa Maria, RS (Brazil); Bortoluzzi, Edson Campanhola [Faculdade de Agronomia e Medicina Veterinaria da Univ. de Passo Fundo, RS (Brazil); Tessier, Daniel [Inst. National de la Recherche Agronomique, Versailles (France)

    2010-04-15

    Purpose: The transfer of soil sediments and phosphorus from terrestrial to aquatic systems is a common process in agricultural lands. The aims of this paper are to quantify the soil phosphorus availability and to characterize phosphorus forms in soil sediments as contaminant agents of waters as a function of anthropic pressures. Materials and methods On three subwatersheds with different anthropic pressure, water and sediment samples were collected automatically in upstream and downstream discharge points in six rainfall events during the tobacco growing season. Phosphorus desorption capacity from soil sediments was estimated by successive extractions with anion exchange resins. First-order kinetic models were adjusted to desorption curves for estimating potentially bioavailable particulate phosphorus, desorption rate constant, and bioavailable particulate phosphorus. Results and discussion The amount of bioavailable particulate phosphorus was directly correlated with the iron oxide content. The value of desorption rate constant was directly related with the total organic carbon and inversely with the iron oxide contents. Phosphate ions were released to solution, on average, twice as rapidly from sediments collected in subwatersheds with low anthropic activity than from those ones of highly anthropic subwatersheds. Anthropic pressure on watershed can engender high sediment discharge, but these solid particles seem to present low phosphorus-releasing capacity to water during transport due to the evidenced high affinity between phosphorus and iron oxide from sediments. Conclusions Anthropic pressure was related with sediment concentration and phosphorus release to aquatic systems. While natural vegetation along streams plays a role on soil and water depuration, it is unable to eliminate the phosphorus inputs intrinsic to the agricultural-intensive systems. Recommendations and perspectives The contamination of water in watershed by phosphates is facilitated by the

  18. Episodic Fan Dissection: Insights from Total Mercury Concentrations on Transport and Storage of Legacy Gold Mining Sediments in California

    Singer, M. B.; James, L.; Aalto, R.

    2008-12-01

    Nineteenth century hydraulic mining in the Sierra Nevada foothills of California displaced ~ 1.0 x 109 m3 of sediment, much of which constructed large tailings fans that linked up into valley-scale fans (e.g. Yuba fan) and graded into the Central Valley more than 50 km downstream. Additionally, ~4.0 x 106 kg of mercury used in gold separation was lost, leading to widespread contamination of mined sediments and the potential for tracing the evolution of the tailings fans over the last century. We conducted total mercury analysis on sediments from a range of geomorphic units spanning the region from the gold mining districts to the Central Valley to investigate aspects of the basin-scale adjustment to this extreme sediment loading. Samples were primarily extracted from bank exposures along vertical sections and from floodplain sediment cores, enabling determination of various phases of deposition and erosion. They were subsequently sieved to 63 microns to normalize samples from different geomorphic units containing a wide range of grain sizes and analyzed for total mercury on a Tekran cold vapor atomic fluorescence spectrophotometry detector. The resulting data show good discrimination in total mercury between the various sedimentary units ranging over two orders of magnitude, wherein prehistoric soils have values ~50 ppb and primary mining tailings contain concentrations up to ~7000 ppb. The data from the Yuba fan, which are corroborated by radionuclides and other geochemistry, support a conceptual model of transport and storage that resembles glacial outwash analogues, wherein successive phases of fan development and dissection can be identified. More importantly, the data suggest ongoing, episodic transport of hydraulic mining sediment from the Sierra piedmont to the lowland valley areas and delta, where conditions are favorable for mercury methylation (conversion of mercury from inorganic to organic forms). This sediment remobilization occurs largely during major

  19. Heavy Metal Concentrations in Water, Sediments and Common Carp (Cyprinus carpio Fish Species from Lake Naivasha, Kenya

    G.M. Ogendi

    2014-08-01

    Full Text Available Heavy metals are potentially toxic to organisms causing lethal and sub lethal effects. Above threshold levels, these metals have been shown to adversely affect both aquatic and terrestrial organisms. Human health may also be impacted negatively through consumption of metal-contaminated foods and water. Lake Naivasha, Kenya, like many freshwater bodies in developing countries is a source of fish and water for human consumption in Naivasha town and its environs. Ironically, the lake receives untreated floricultural, agricultural and industrial effluents from its catchment area. In the recent past, there have been unconfirmed reports that fish from this lake are contaminated with heavy metals mainly Cu, Hg, Cd and Pb to levels that are harmful to humans. It is against this background that this study was conducted to determine the sources of the aforementioned heavy metals in the lake, their concentrations in water and sediments and in common carp (Cyprinus carpio that constitutes a major portion of the Lake Naivasha fishery. Water, sediment and fish samples were collected from purposefully selected sites in six sampling occasions during both the dry and wet seasons. Analyses for heavy metals in fish, sediment and water samples were done using an Atomic Absorption Spectrophotometer (AAS. The study findings indicate that the heavy metal concentrations in the water and sediments collected from impacted sites were significantly higher (p<0.05 compared to those from unexpected sites. In spite of this, the metal concentrations in water were significantly lower than those recommended by the WHO and USEPA as drinking water guideline values. Metal concentrations in C. carpio were also significantly lower (p<0.05 than the World Health Organization (WHO recommended levels for fish intended for human consumption. Based on these findings, it is safe to conclude that drinking water and fish collected from Lake Naivasha do not pose immediate health risks to human

  20. Assessment of heavy metal concentrations in water, sediment and biota (fish and crabs) samples from the Densu Delta

    The aim of the study was assess the concentration of some selected heavy metals in water, sediments and biota (fish and crab) sampled from the Densu Delta. In situ and laboratory based analysis were carried out to measure the following physicochemical properties of surface water from the delta; temperature, pH, electrical conductivity (EC), salinity, total dissolved solids (TDS), alkalinity, sodium ion concentration (Na+), potassium ion concentration (K+), chloride ion concentration (Cl), bicarbonate concentration, phosphate concentration, nitrate concentration, sulphate concentration and biochemical oxygen demand (BOD). Heavy metal (Fe, Zn, Cu, Ni, Cd, Cr, Pb and Hg) concentrations in water, sediments, fish and crab sampled at six sites from the Densu Delta wetland in the month of December, 2009 were analysed using VARIAN Fast Sequential Atomic Absorption Spectrophotometer (AAS) model AA240 FS. Two fish species; Blackchin tilapia (Sarotherodon melanotheron), White mullet (Mugil curema) and one species of crab; Blue swimming crab (Callinectes amnicola) were collected from the Densu Delta wetland and analysed. Heavy metal contents in the fish were higher in gill tissue than muscle tissue while in crabs concentrations were higher in the soft tissue than the shell. Levels of Fe, Zn and Cu in the muscle tissue of S. melanotheron were greater than the levels detected in the muscle tissue of M. curema. Cd, Ni and Hg were detected in gill tissue but not in the muscle tissue of S. melanotheron, M. curema on the other hand contained these metals in both gill and muscle tissue. The maximum level of Fe (34.98 mg/L), Zn (25.08 mg/L) in the muscle of S. melanotheron was observed at Bortianor and Zn (2.70 mg/L) was observed at Tetegu. In the M. curema, the maximum level of Fe (34.66 mg/L), Zn (15.9 mg/L) and Cu (1.43 mg/L) was detected at Aplaku, Tetegu and Faana respectively. Heavy metal concentrations were higher in sediment than water. The presence of elevated levels of Cd

  1. Seasonal variations of concentrations, profiles and possible sources of polycyclic aromatic hydrocarbons in sediments from Taihu Lake, China

    Zhang, Yuan; Guo, Chang-Sheng; Xu, Jian [Chinese Research Academy of Environmental Sciences, Beijing (China). State Key Laboratory of Environmental Criteria and Risk Assessment, and Laboratory of Riverine Ecological Conservation and Technology; Shi, Guo-Liang; Tian, Ying-Ze; Feng, Yin-Chang; Wang, Yu-Qiu [Nankai Univ., Tianjin (China). State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control

    2012-06-15

    Obtaining a better understanding of the concentrations and origins of polycyclic aromatic hydrocarbons (PAHs) in the sediments Taihu Lake, China, is of paramount importance for the environmental protection and remediation of this lake. To investigate temporal and spatial variations in PAH concentrations, composition and possible source categories, 29 sediment samples were collected from Taihu Lake during both the flooding and dry seasons of the lake. Materials and methods: Fifteen US Environmental Protection Agency priority PAHs were detected in 58 surface sediments (29 for each season) by gas chromatograph/mass selective detection, following extraction by accelerated solvent extraction. The concentrations of the total and individual PAHs in the flooding season were higher than those in the dry season, suggesting that high levels of fishing activity may be an important contributor to PAH pollution in the flooding season. The fractions of high molecular weight PAHs in the flooding season ranged from 63 % to 71 % and were higher than those in the dry season (which ranged from 52 % to 65 %). These results indicate that vehicle exhaust may be a more important pollutant source in the flooding season than in the dry season. Diagnostic ratios, principal component analysis and hierarchical cluster analysis were used to study possible source categories in the different seasons. Consistent results were obtained for all techniques. Seasonal and spatial variations were also investigated by the coefficient of divergence method. The results of previous studies support the conclusion of source identification. Vehicle emissions were the dominant contributor to PAHs in the flooding season, while PAHs in the dry season sediments may have come from multiple sources. The findings of this study may provide a theoretical basis for seasonal PAH control strategies for Taihu Lake. (orig.)

  2. Effects of near-bottom water oxygen concentration on biogeochemical cycling of C, N and S in sediments of the Gulf of Gdansk (southern Baltic)

    Lukawska-Matuszewska, Katarzyna; Kielczewska, Joanna

    2016-04-01

    Sediments from four sampling sites in the Gulf of Gdansk were sampled to test how different oxygen concentrations in near-bottom water affects biogeochemical cycling of C, N and S. Vertical distributions of content of organic carbon (OC), total nitrogen (TN) and total sulfur (TS) and number of sulfate-reducing bacteria (SRB) in sediments were determined. Pore water total alkalinity (TA), dissolved inorganic carbon (DIC), sulfate, hydrogen sulfide, ammonium and phosphate were analyzed and benthic fluxes of DIC, hydrogen sulfide and ammonium were calculated. Concentrations of OC and TN decreased and concentration of TS increased with sediment depth. Highest concentrations of OC, TN and TS were observed in silty clay sediments from hypoxic and anoxic sediments below the permanent halocline. Organic matter (OM) accumulation in sediments and oxygen deficiency in near-bottom water stimulate preservation of OC and burial of TS in this area. Concentrations of TA, DIC, hydrogen sulfide, ammonium and phosphate in pore water increased, while concentration of sulfate decreased with sediment depth. Hydrogen sulfide, ammonium and phosphate was a significant additional source of TA in pore water under hypoxic and anoxic conditions. Mineralization of OM at oxygen concentrations water DIC fluxes under hypoxic and anoxic conditions were much lower and ranged from 1015 to 1208 μmol m-2 d-1.

  3. Evaluation of the boundary condition influence on PAH concentrations in the water column during the sediment dredging of a port.

    Cutroneo, L; Castellano, M; Carbone, C; Consani, S; Gaino, F; Tucci, S; Magrì, S; Povero, P; Bertolotto, R M; Canepa, G; Capello, M

    2015-12-30

    The mobilisation of sediments and related contaminants connected to dredging activities is one of the most critical issues to the environmental risk and exposure assessment of a dredging project. The aim of this paper was an investigation of the mobilisation of polycyclic aromatic hydrocarbons (PAHs) due to the dredging of the Port of Genoa (Italy) to identify the temporal and spatial extent of the contaminant transport, and the influence of the dredging and the boundary conditions on it. The results showed relatively low background PAH concentrations in the water column and confirmed the dredging as the primary rising factor of concentrations in the water column, but also showed a complex scenario in which the different environmental and dredging factors forced the concentrations at different levels and moments. The post dredging phase showed PAH values close to the background conditions and the concentrations remained relatively high only for a few PAHs. PMID:26517941

  4. Effect of Hydrograph Separation on Suspended Sediment Concentration Predictions in a Forested Headwater with Thick Soil and Weathered Gneiss Layers

    Naoki Kabeya

    2014-06-01

    Full Text Available Two-component hydrograph separation using oxygen-18 concentrations was conducted at a sediment runoff observation weir installed in a small subcatchment of a forested gneiss catchment in Japan. The mean soil thickness of this catchment is 7.27 m, which comprises 3.29 m of brown forest soil (A and B layers and a 3.98-m layer of heavily weathered gneiss. Data were collected for a storm on 20–21 May 2003, and the percentage of event water separated by the stable isotope ratio in comparison with the total rainfall amount was about 1%. This value is within the ratio of a riparian zone in a drainage area. Temporal variation of suspended sediment concentration exhibited higher correlation with the event water component than with the total runoff or pre-event water component. This shows that the riparian zone causes rainwater to flow out quickly during a rain event, and that this is an important area of sediment production and transportation in a forested headwater with thick soil and weathered gneiss layers.

  5. Investigation of the concentration, distribution, and inventory of radionuclides in the sediment of Process Waste System Basin 3524

    Process Waste System Basin 3524 is used as a collection basin for process liquid waste from facilities at the Oak Ridge National Laboratory. This investigation was conducted to determine the radionuclide concentrations, distributions, and inventory of the sediments in this basin in preparation for future decontamination and decommissioning activities. Twenty-four sediment cores were extracted from the basin and 80 aliquots were analyzed for their radionuclide concentrations. The sediment is estimated to contain a total of 5.5 x 1012 Bq (150 Ci) of activity, 87% of which is contributed by two radionuclides, 137Cs (68%) and 90Sr (19%). The radionuclide content is estimated as follows: 137Cs, 3.77 x 1012 Bq (102 Ci); 90Sr, 1.07 x 1012 Bq (29 Ci); gross alpha, 4.06 x 1011 Bq (11 Ci); 241Am, 1.70 x 1011 Bq (4.6 Ci); 60Co, 8.32 x 1010 Bq (2.2 Ci); and 154Eu, 3.35 x 1010 Bq (0.9 Ci). 9 references, 8 figures, 7 tables

  6. Detailed uranium hydrogeochemical and stream sediment reconnaissance data release for the eastern portion of the Montrose NTMS Quadrangle, Colorado, including concentrations of forty-five additional elements

    In September and October 1979, the Los Alamos Scientific Laboratory (LASL) conducted a detailed geochemical survey for uranium primarily in the Sawatch Range in the eastern part of the Montrose National Topographic Map Series (NTMS) quadrangle, Colorado, as part of the National Hydrogeochemical and Stream Sediment Reconnaissance (HSSR). Totals of 1034 water and 2087 sediment samples were collected from streams and springs from 2088 locations within a 5420-km2 area. Statistical data for uranium concentrations in water and sediment samples are presented. Elemental concentration, field measurement, weather, geologic, and geographic data for each sample location are listed for waters and for sediments in appendices. Uranium/thorium ratios for sediment samples are also included. This report contains uranium analyses for water samples and multielement analyses for sediment samples. Sediments were analyzed for uranium and thorium as well as Al, Sb, As, Ba, Be, Bi, Cd, Ca, Ce, Cs, Cl, Cr, Co, Cu, Dy, Eu, Au, Hf, Fe, La, Pb, Li, Lu, Mg, Mn, Ni, Nb, K, Rb, Sm, Sc, Se, Ag, Na, Sr, Ta, Tb, Sn, Ti, W, V, Yb, Zn, and Zr. All elemental analyses were performed at the LASL. Water samples were analyzed for uranium by fluorometry. Sediments were analyzed for uranium by delayed neutron counting. Other elemental concentrations in sediments were determined by neutron activation analysis for 31 elements, by x-ray fluorescence for 12 elements, and by arc-source emission spectrography for 2 elements. Descriptions of procedures as analytical precisions and detection limits are given in the appendix

  7. Guidelines and Procedures for Computing Time-Series Suspended-Sediment Concentrations and Loads from In-Stream Turbidity-Sensor and Streamflow Data

    Rasmussen, Patrick P.; Gray, John R.; Glysson, G. Douglas; Ziegler, Andrew C.

    2009-01-01

    In-stream continuous turbidity and streamflow data, calibrated with measured suspended-sediment concentration data, can be used to compute a time series of suspended-sediment concentration and load at a stream site. Development of a simple linear (ordinary least squares) regression model for computing suspended-sediment concentrations from instantaneous turbidity data is the first step in the computation process. If the model standard percentage error (MSPE) of the simple linear regression model meets a minimum criterion, this model should be used to compute a time series of suspended-sediment concentrations. Otherwise, a multiple linear regression model using paired instantaneous turbidity and streamflow data is developed and compared to the simple regression model. If the inclusion of the streamflow variable proves to be statistically significant and the uncertainty associated with the multiple regression model results in an improvement over that for the simple linear model, the turbidity-streamflow multiple linear regression model should be used to compute a suspended-sediment concentration time series. The computed concentration time series is subsequently used with its paired streamflow time series to compute suspended-sediment loads by standard U.S. Geological Survey techniques. Once an acceptable regression model is developed, it can be used to compute suspended-sediment concentration beyond the period of record used in model development with proper ongoing collection and analysis of calibration samples. Regression models to compute suspended-sediment concentrations are generally site specific and should never be considered static, but they represent a set period in a continually dynamic system in which additional data will help verify any change in sediment load, type, and source.

  8. Anaerobic Microflora of Everglades Sediments: Effects of Nutrients on Population Profiles and Activities

    Drake, H. L.; Aumen, N. G.; Kuhner, C.; Wagner, C.; Griesshammer, A.; Schmittroth, M.

    1996-01-01

    Everglades sediments (wetland soils) near sources of agricultural runoff had low redox potentials, were blackened with sulfide, and displayed high porewater phosphorus (total) concentrations and high water column conductivities. These sediments yielded 10(sup3)- to 10(sup4)-fold-higher numbers of culturable anaerobes, including methanogens, sulfate reducers, and acetate producers, than did sediments from Everglades and Lake Okeechobee comparative control sites not as directly associated with ...

  9. Polybrominated diphenyl ethers in sediments from the Southern Yellow Sea: Concentration, composition profile, source identification and mass inventory.

    Wang, Guoguang; Peng, Jialin; Xu, Xiang; Zhang, Dahai; Li, Xianguo

    2016-02-01

    The Southern Yellow Sea (SYS) is believed to be influenced by the contaminants from mainland China and the Korean peninsula. Here we report the first record about concentrations of polybrominated diphenyl ethers (PBDEs) in the sediments of the SYS. The concentrations of ∑(7)PBDEs (BDE-28, 47, 99, 100, 153, 154, 183) and BDE-209 were 0.064-0.807 ng g(-1) (dry weight) and 0.067-1.961 ng g(-1) with a mean value of 0.245 ng g(-1) and 0.652 ng g(-1), respectively. These are distinctively low compared with the PBDE levels previously reported in other regions of the world. PBDE concentrations gradually increased from the coastal areas to the central mud area. BDE-209 was the dominant congener, accounting for 70.2-91.6% of the total PBDEs. Congener profiles of PBDEs were similar to those in sediments from the Bohai Sea (BS), Laizhou Bay and modern Yellow River, which might be a tentative indication that they shared similar sources. Principal component analysis (PCA) revealed that PBDEs in the SYS were mainly from continental runoff (69.0%) and atmospheric deposition (31.0%). Depth profile of PBDEs in a sediment core collected from the edge of the central mud area showed that concentration of BDE-209 rapidly increased in recent years, which is in accordance with the replacement in demand and consumption of Penta- and Octa-BDEs by the Deca-BDE. Compared with BS, East China Sea, Erie and Ontario, the SYS was a relatively weak sink of PBDEs (0.102-1.288 t yr(-1) for ∑(7)PBDEs and 0.107-3.129 t yr(-1) for BDE-209) in the world. PMID:26580721

  10. Contribution to the electrochemical study of corrosion in low-conductivity environments. Application to the study of the behaviour of austenitic stainless steels in concentrated solutions of acetic acid

    As the use of conventional electrochemical methods to study metal and alloy corrosion in concentrated solutions of acetic acid is challenged by difficulties due the low conductivity of these environments, the first part of this research thesis proposes a critical, theoretical and experimental study of these difficulties. It notably evokes the use of electrochemical impedance techniques, the different compensation devices and means of correction of the ohmic voltage drop, and artefacts used during high frequency impedance measurements in lesser conductive solutions. The second part addresses the characterization of the corrosion behaviour of austenitic stainless steels in a concentrated acetic acid at 25 and 95 degrees C. Electrochemical techniques are coupled with analytical methods (solution analysis, sample surface analysis after corrosion tests). The roles of molybdenum as alloying element, of dissolved oxygen, of impurities (sulfites) or of formic acid additions are studied and discussed

  11. Exploring the uncertainty in attributing sediment contributions in fingerprinting studies due to uncertainty in determining element concentrations in source areas.

    Gomez, Jose Alfonso; Owens, Phillip N.; Koiter, Alex J.; Lobb, David

    2016-04-01

    One of the major sources of uncertainty in attributing sediment sources in fingerprinting studies is the uncertainty in determining the concentrations of the elements used in the mixing model due to the variability of the concentrations of these elements in the source materials (e.g., Kraushaar et al., 2015). The uncertainty in determining the "true" concentration of a given element in each one of the source areas depends on several factors, among them the spatial variability of that element, the sampling procedure and sampling density. Researchers have limited control over these factors, and usually sampling density tends to be sparse, limited by time and the resources available. Monte Carlo analysis has been used regularly in fingerprinting studies to explore the probable solutions within the measured variability of the elements in the source areas, providing an appraisal of the probability of the different solutions (e.g., Collins et al., 2012). This problem can be considered analogous to the propagation of uncertainty in hydrologic models due to uncertainty in the determination of the values of the model parameters, and there are many examples of Monte Carlo analysis of this uncertainty (e.g., Freeze, 1980; Gómez et al., 2001). Some of these model analyses rely on the simulation of "virtual" situations that were calibrated from parameter values found in the literature, with the purpose of providing insight about the response of the model to different configurations of input parameters. This approach - evaluating the answer for a "virtual" problem whose solution could be known in advance - might be useful in evaluating the propagation of uncertainty in mixing models in sediment fingerprinting studies. In this communication, we present the preliminary results of an on-going study evaluating the effect of variability of element concentrations in source materials, sampling density, and the number of elements included in the mixing models. For this study a virtual

  12. The Suspended Sediment Concentration Distribution in the Bohai Sea, Yellow Sea and East China Sea

    BIAN Changwei; JIANG Wensheng; Richard J.Greatbatch; DING Hui

    2013-01-01

    The distribution of the suspended sediment eoncentration (SSC) in the Bohai Sea,Yellow Sea and East China Sea (BYECS) is studied based on the observed turbidity data and model simulation results.The observed turbidity results show that (i)the highest SSC is found in the coastal areas while in the outer shelf sea areas turbid water is much more difficult to observe,(ii) the surface layer SSC is much lower than the bottom layer SSC and (iii) the winter SSC is higher than the summer SSC.The Regional Ocean Modeling System (ROMS) is used to simulate the SSC distribution in the BYECS.A comparison between the modeled SSC and the observed SSC in the BYECS shows that the modeled SSC can reproduce the principal features of the SSC distribution in the BYECS.The dynamic mechanisms of the sediment erosion and transport processes are studied based on the modeled results.The horizontal distribution of the SSC in the BYECS is mainly determined by the current-wave induced bottom stress and the fine-grain sediment distribution.The current-induced bottom stress is much higher than the wave-induced bottom stress,which means the tidal currents play a more significant role in the sediment resuspension than the wind waves.The vertical mixing strength is studied based on the mixed layer depth and the turbulent kinetic energy distribution in the BYECS.The strong winter time vertical mixing,which is mainly caused by the strong wind stress and surface cooling,leads to high surface layer SSC in winter.High surface layer SSC in summer is restricted in the coastal areas.

  13. The effect of combination treatment with trenbolone acetate and estradiol-17β on skeletal muscle expression and plasma concentrations of oxytocin in sheep.

    Kongsuwan, K; Knox, M R; Allingham, P G; Pearson, R; Dalrymple, B P

    2012-07-01

    Implantation of trenbolone acetate (TBA) in conjunction with estradiol-17β (E(2)) increases growth, feed conversion efficiency, and carcass leanness in cattle. Our previous study in Brahman steers suggested that the neuropeptide hormone oxytocin (OXT) may be involved in increasing muscle growth after TBA-E(2) treatment. The present study aimed to determine whether OXT mRNA expression in the longissimus muscle (LM) is also up-regulated in TBA-E(2-)implanted wethers as has been found in steers. Real-time quantitative PCR was used to measure the expression of the gene encoding the OXT precursor, three genes with increased expression in the LM muscle of TBA-E(2)-treated steers, MYOD1 (muscle transcription factor), GREB1 (growth regulation by estrogen in breast cancer 1), and WISP2 (Wnt-1 inducible signaling pathway protein 2), and two genes encoding IGF pathway proteins, IGF1, IGFR, in the LM of both untreated and TBA-E(2)-treated wethers. The expression of OXT mRNA in wethers that received the TBA-E(2) treatment was increased ~4.4-fold (P = 0.01). TBA-E(2) treatment also induced a 2.3-fold increase in circulating OXT (P = 0.001). These data, together with the observation that untreated wethers had much higher baseline concentrations of circulating OXT than previously observed in steers, suggest that wethers and steers have quite different OXT hormone systems. TBA-E(2) treatment had no effect on the expression of IGF1, IGFR, and the muscle regulatory gene MYOD1 mRNA levels in wethers (P ≥ 0.15), but there was an increase in the expression of the two growth-related genes, GREB1 (P = 0.001) and WISP2 (P = 0.04). Both genes are common gene targets for both the estrogen and androgen signaling pathways. Consequently, their actions may contribute to the positive interaction between TBA and E(2) on additive improvements on muscle growth. PMID:22503145

  14. 226Ra concentrations in crayfish tissues, water, and sediments from the Serpent River Basin in Northeastern Ontario, Canada

    Lower Serpent River, as well as Elliot, McCarthy and McCabe lakes had highest 226Ra contamination, Chrisman, Quirke and Whiskey lakes a moderate one, Flack and Semiwhite lakes and the 'distant' control, Lake Wanapitei, the lowest. 226Ra activity in Cambarus robustus tissues was directly related to their background levels. Thus, concentration coefficient (tissue/sediment concentrations) for 226Ra ranged from 0.53 to 0.74 in highly contaminated Elliot and McCarthy lakes, 0.28 to 0.59 in moderately contaminated Quirke and Whiskey lakes, and from 0.27 to 3.44 in least contaminated Semiwhite and Flack lakes. Among various organs analysed, exoskeleton showed the highest (43.04 - 90.69%) and the tail muscles the lowest (2.95 -17.14%) 226Ra activity. 226Ra concentrations in the alimentary canal were considered a part of the ambient environment as they had not been absorbed

  15. Analysis of Selenium Concentrations in Biota and Sediment from Stewart Lake and the Middle Green River, 1995-1999: Evaluation of Phase IV Remediation

    US Fish and Wildlife Service, Department of the Interior — This report presents the analytical results and analysis of selenium concentrations in biota and sediment samples collected by the U.S. Fish and Wildlife Service...

  16. Heavy metal concentrations in soils, sediments, and surface water of mineral licks, Dunkel Mine, Denali National Park and Preserve, Alaska: GLARSU report #10

    US Fish and Wildlife Service, Department of the Interior — This report covers heavy metal concentrations in soils, sediments, and surface water of mineral licks in Dunkel Mine, Denali National Park and Preserve. The...

  17. A step decrease in sediment concentration in a highly modified tidal river delta following the 1983 El Niño floods

    Hestir, Erin L.; Schoellhamer, David H.; Morgan-King, Tara; Ustin, Susan L.

    2013-01-01

    Anthropogenic activities in watersheds can have profound effects on sediment transport through river systems to estuaries. Disturbance in a watershed combined with alterations to the hydro-climatologic regime may result in changes to the sediment flux, and exacerbate the impacts of extreme events (such as large-magnitude floods) on sediment transport. In the San Francisco Estuary, suspended sediment has been declining over the past 30 years as a result of declining sediment supply, contributing to dramatic changes in the ecology and geomorphology of the estuary. However, the decline has not been gradual. Recent observations of an abrupt decrease in suspended sediments in the San Francisco Bay have been explained by a model that suggests that the step change has occurred due to exceedance of a sediment regulation threshold that triggered the change from a sediment transport regime to a supply-limited system. We investigated structural changes in the historical record of total suspended solids (TSS) concentration measured in the upper estuary to verify the model predictions. TSS in the upper estuary exhibited an abrupt step decrease in 1983 corresponding to the record-high winter and summer flows from the 1982 to 1983 El Niño event. After this step change, TSS concentrations had a significant declining trend despite subsequent near-record high flows. The abrupt change in TSS followed by the declining trend provides evidence for the hypothesis of sediment supply limitation in the San Francisco Estuary.

  18. A Semi-Analytical Model for Remote Sensing Retrieval of Suspended Sediment Concentration in the Gulf of Bohai, China

    Jin-Ling Kong; Xiao-Ming Sun; David W. Wong; Yan Chen; Jing Yang; Ying Yan; Li-Xia Wang

    2015-01-01

    Suspended sediment concentration (SSC) is one of the most critical parameters in ocean ecological environment evaluation and it can be determined using ocean color remote sensing (RS). The purpose of this study is to develop a model that provides a reliable and sensitive evaluation of SSC retrieval using RS data. Data were acquired for and gathered from the Gulf of Bohai where SSC levels are relatively low with an average value below 30 mg·L−1. The study indicates that the most sensitive ban...

  19. A new XRF probe for in-situ determining concentration of multi-elements in ocean sediments

    Ge Liang Quan; Zhou Si Chun; Lin Ling; Lin Yan Chang; Ren Jia Fu

    2001-01-01

    The author introduces a new X-ray fluorescence probe for in-situ determining the concentration of multi-elements in ocean sediments. The probe consists of Si-Pin X-ray detector with an electro-thermal colder, two isotope sources, essential electrical signal processing units and a notebook computer. More than 10 elements can be simultaneously determined at a detection limit of (10-200) x 10 sup - sup 6 and precision of 5%-30% without liquid Nitrogen supply. tests show that the probe can perform the analytical tasks under the water at the depth of less than 1000 meters

  20. A Survey of Mercury Concentrations in Soft Tissue of Bivalves Callista umbonella, Saccostrea cucullata and Sediment in the Coastline of Bandar Abbas

    Zahra Bagheri; Alireza Riyahi Bakhtiari

    2014-01-01

    Background and Objectives: The present study was designed to determine total mercury concentrations in sediment and the soft tissues of two bivalve species, Saccostrea cucullata and Callista umbonella, in coastline of Bandar Abbas in 2011. Materials and Methods: Generally, 67 bivalves and 10 sediment samples were collected from two stations (terminal of Bandar Abbas and tourism park of Soro). We measured total mercury concentrations in each sample using Mercury Analyzer (Leco AMA 254). ...

  1. Use of pre-industrial floodplain lake sediments to establish baseline river metal concentrations downstream of Alberta oil sands: a new approach for detecting pollution of rivers

    In the Alberta oil sands region, insufficient knowledge of pre-disturbance reference conditions has undermined the ability of the Regional Aquatics Monitoring Program (RAMP) to detect pollution of the Athabasca River, because sampling began three decades after the industry started and the river naturally erodes oil-bearing strata. Here, we apply a novel approach to characterize pre-industrial reference metal concentrations in river sediment downstream of Alberta oil sands development by analyzing metal concentrations in sediments deposited in floodplain lakes of the Athabasca Delta during 1700–1916, when they were strongly influenced by Athabasca River floodwaters. We compared results to metal concentrations in surficial bottom sediments sampled by RAMP (2010–2013) at downstream sites of the Athabasca River and distributaries. When normalized to lithium content, concentrations of vanadium (a metal of concern in the oil sands region) and other priority pollutants (Be, Cd, Cr, Cu, Pb, Ni, Zn) in nearly all of the RAMP river sediment samples lie below the upper 95% prediction interval linearly extrapolated from the river-derived lake sediments. Assuming the RAMP protocols obtained recently deposited sediment, this indicates that the metal concentrations in downstream Athabasca River sediment have not increased above pre-disturbance levels. Reference conditions derived from the lake sediment data were used to develop profiles of metal residual concentrations versus time for the RAMP river sediment data, which provides an excellent tool for decision-makers to identify and quantify levels of metal pollution for any given sample, and to monitor for future trends. We recommend that the approach be applied to resurrect the utility of RAMP data at other river sampling locations closer to the development, and for ongoing risk assessment. The approach is also readily transferable to other rivers where insufficient pre-disturbance reference data impairs an ability to

  2. Fate of polychlorinated biphenyls in a contaminated lake ecosystem: Combining equilibrium passive sampling of sediment and water with total concentration measurements of biota

    Mäenpää, Kimmo; Leppänen, Matti T.; Figueiredo, Kaisa;

    2015-01-01

    hydrophobic organic chemicals in biota lipids. The authors' aim was to assess the equilibrium status of polychlorinated biphenyls (PCBs) in a contaminated lake ecosystem and along its discharge course using equilibrium sampling devices for measurements in sediment and water and by also analyzing biota. The...... authors used equilibrium sampling devices (silicone rubber and polyethylene [PE]) to determine freely dissolved concentrations and chemical activities of PCBs in the water column and sediment porewater and calculated for both phases the corresponding equilibrium concentrations and chemical activities in...... model lipids. Overall, the studied ecosystem appeared to be in disequilibrium for the studied phases: sediment, water, and biota. Chemical activities of PCBs were higher in sediment than in water, which implies that the sediment functioned as a partitioning source of PCBs and that net diffusion occurred...

  3. Effect of dietary 7-ketocholesterol, pure, or oxidized cholesterol on hepatic 3-hydroxy-3-methylglutaryl-coenzyme A reductase activity, energy balance, egg cholesterol concentration, and 14C-acetate incorporation into yolk lipids of laying hens.

    Vargas, R E; Allred, J B; Biggert, M D; Naber, E C

    1986-07-01

    Experiments were conducted to study the effect of 7-ketocholesterol (7-k) in the presence or absence of pure cholesterol (PCH) or oxidized cholesterol (OCH) in diets of laying hens on reproductive performance and several parameters of cholesterol metabolism. In the first experiment, cholesterol synthesis and transport was examined by the in ovo incorporation of 14C-acetate into yolk triglycerides and cholesterol. Energy balances were also conducted. In the second experiment, hepatic 3 hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase activity was measured in vitro to evaluate potential cholesterol synthesis. In both experiments, reproductive performance and egg yolk cholesterol concentration were measured. Dietary PCH or OCH (.5%) significantly reduced relative acetate incorporation into yolk cholesterol, while 7-k (.025%) had no effect on carbon flow from acetate into egg cholesterol. While 7-k alone did not alter total yolk cholesterol concentration, it moderated the effect of PCH or OCH on increasing yolk cholesterol concentration. No consistent effects of dietary sterols on reproductive performance or energy balance were observed. Hepatic HMG CoA reductase activity was dramatically suppressed by feeding PCH or OCH and moderately suppressed by 7-k. In combination with PCH or OCH, 7-k did not further depress enzyme activity. The observations that 7-k alone depressed hepatic HMG-CoA reductase activity, without changing relative acetate incorporation into yolk cholesterol while limiting cholesterol deposition in egg yolk from PCH or OCH, is interpreted to mean that 7-k may stimulate sterol transport and excretion while limiting cholesterol synthesis. PMID:3748946

  4. Bioavailability and concentration of heavy metals in the sediments and leaves of grey mangrove, Avicennia marina (Forsk.) Vierh, in Sirik Azini Creek, Iran.

    Parvaresh, Hossein; Abedi, Zahra; Farshchi, Parvin; Karami, Mahmood; Khorasani, Nematullah; Karbassi, Abdolreza

    2011-11-01

    The concentration and bioavailability of Ni, Cu, Cd, Zn, and Pb in the sediments and leaves of grey mangrove, Avicennia marina, were studied throughout Sirik Azini creek (Iran) with a view to determine heavy metals bioavailability, and two methods were used. Results show that Zn and Ni had the highest concentrations in the sediments, while Cd and Cu were found to have the lowest concentrations in the sediments. Compared to the mean concentrations of heavy metals in sedimentary rock (shales), Zn and Cu showed lower concentration, possibly indicating that the origin of these heavy metals is natural. A geo-accumulation index (Igeo) was used to determine the degree of contamination in the sediments. Igeo values for Zn, Cu, Pb, and Ni showed that there is no pollution from these metals in the study area. As heavy metal concentrations in leaves were higher than the bioavailable fraction of metals in sediments, it follows that bioconcentration factors (leaf/bioavailable sediment) for some metals were higher than 1. PMID:21053092

  5. Estimation of suspended sediment concentrations from remotely sensed spectral reflectance: a field calibration for the Yellow River

    Qu, Liqin; Civco, Daniel; Lei, Tingwu; Yang, Xiusheng

    2014-06-01

    The dynamic sediment distribution in large rivers with dams constructed has often been the focus of considerable attention because of their potential adverse environmental impacts. Sedimentation modeling and environmental assessment of man-made projects are often hindered by the lack of sediment measurements with spatial details. This study aimed to investigate the method used to estimate the suspended sediment concentrations (SSCs) from on-site spectral measurements. The study investigated the spectral signature of river water from the natural channel and Sanmenxia Reservoir on the Yellow River. A field spectral survey was conducted through on-site spectral measurements by using a spectroradimeter and SSC estimation by sampling. Reectance at 750 nm to 950 nm, with all correlation coefficient (r) between SSC and reectance > 0:7, seemed to be the appropriate range for SSC estimation. Simulated Landsat Enhanced Thematic Mapper Plus Band 4 (760 nm to 900 nm) was used to build the single band model for estimating SSC. The results confirmed that the exponential model based on the relationship between SSC and reectance (R2 = 0:92, root mean square error [RMSE]= 0:241 g=l) was better than the linear model between reectance and logarithm-transformed SSC (R2 = 0:90, RMSE = 0:310 g=l). We also applied the Spectral Mixing Algorithm (SMA) from the tank experiment to the on-site spectral measurements. The result showed that the SMA models performed as well as the single band exponential model (R2 = 0:86, RMSE = 0:280 g=l). However, the valid range for application was improved from 1:99 g=l to 347 g=l. This study could provide critical instructional assistance for estimating SSC directly from remote sensing data.

  6. Evaluation of the anthropogenic radionuclide concentrations in sediments and fauna collected in the Beaufort Sea and northern Alaska

    This study was performed to establish a quality controlled data set about the levels of radio nuclide activity in the environment and in selected biota in the U.S. Arctic. Sediment and biota samples were collected by the National Oceanic and Atmospheric Administration (NOAA), the National Biological Service, and the North Slope Borough's Department of Wildlife Management to determine the impact of anthropogenic radionuclides in the Arctic. The results summarized in this report are derived from samples collected in northwest Alaska with emphasis on species harvested for subsistence in Barrow, Alaska. Samples were analyzed for the anthropogenic radionuclides 90Sr, 137Cs, 238Pu, 239Pu, 240Pu and 241Am. The naturally occurring radionuclides 40K, 212Pb and 214Pb were also measured. One goal of this study was to determine the amounts of anthropogenic radionuclides present in the Beaufort Sea. Sediment samples were isotopically fingerprinted to determine the sources of radio nuclide activities. Biota samples of subsistence and ecological value were analyzed to search for evidence of bio-accumulation of radionuclides and to determine the radiation exposures associated with subsistence living in northern Alaska. The anthropogenic radio nuclide content of sediments collected in the Beaufort Sea was predominantly the result of the deposition of global fallout. No other sources of anthropogenic radionuclides could be conclusively identified in the sediments. The anthropogenic radio nuclide concentrations in fish, birds and mammals were very low. Assuming that ingestion of food is an important pathway leading to human contact with radioactive contaminants and given the dietary patterns in coastal Arctic communities, it can be surmised that marine food chains are presently not significantly affected

  7. Uranium hydrogeochemical and stream sediment reconnaissance data release for the Butte NTMS Quadrangle, Montana, including concentrations of forty-two additional elements

    This report contains data collected during a geochemical survey for uranium in the Butte National Topographic Map Series (NTMS) quadrangle of west-central Montana. Histograms and statistical data for uranium concentrations in water and sediment samples and thorium concentrations in sediment samples are given. Elemental concentration, field measurement, weather, geologic, and geographic data for each sample location are listed for waters and for sediments. Uranium/thorium ratios for sediment samples are also included. This report contains uranium analyses for water samples and multielement analyses for sediment samples. A supplemental report containing the results of multielement analyses of water samples will be open filed in the near future. Sediments were analyzed for uranium and thorium as well as aluminum, antimony, barium, beryllium, bismuth, cadmium, calcium, cerium, cesium, chlorine, chromium, cobalt, copper, dysprosium, europium, gold, hafnium, iron, lanthanum, lead, lithium, lutetium, magnesium, manganese, nickel, niobium, potassium, rubidium, samarium, scandium, silver, sodium, strontium, tantalum, terbium, tin, titanium, tungsten, vanadium, ytterbium, and zinc. All elemental analyses were performed at the LASL. Water samples were initially analyzed for uranium by fluorometry. All water samples containing more than 40 ppB uranium were reanalyzed by delayed-neutron counting (DNC). All sediments were analyzed for uranium by DNC. Other elemental concentrations in sediments were determined by neutron activation analysis for 31 elements, by x-ray fluorescence for 9 elements, and by arc-source emission spectrography for 2 elements. Analytical results for sediments are reported as parts per million. Descriptions of procedures used for analysis of water and sediment samples as well as analytical precisions and detection limits are given

  8. Bioleaching of heavy metals from contaminated sediment by indigenous sulfur-oxidizing bacteria in an air-lift bioreactor: effects of sulfur concentration.

    Chen, Shen-Yi; Lin, Jih-Gaw

    2004-01-01

    The effects of sulfur concentration on the bioleaching of heavy metals from the sediment by indigenous sulfur-oxidizing bacteria were investigated in an air-lift reactor. Increasing the sulfur concentration from 0.5 to 5 g/l enhanced the rates of pH reduction, sulfate production and metal solubilization. A Michaelis-Menten type equation was used to explain the relationships between sulfur concentration, sulfate production and metal solubilization in the bioleaching process. After 8 days of bioleaching, 97-99% of Cu, 96-98% of Zn, 62-68% of Mn, 73-87% of Ni and 31-50% of Pb were solubilized from the sediment, respectively. The efficiency of metal solubilization was found to be related to the speciation of metal in the sediment. From economical consideration, the recommended sulfur dosage for the bioleaching of metals from the sediment is 3g/l. PMID:15276736

  9. The Role of Sedimentation on Waters Edge and Analysis Pb and Zn Concentration in Water from Sentani Lake, Jayapura-Papua

    Frans Deminggus

    2015-05-01

    Full Text Available We have conducted research on the role of sediment on the waters edge and content analysis of metal concentrations of lead (Pb, zinc (Zn in the water of Sentani Lake in Jayapura, Papua Province. The experiment was conducted in April 2013. The study was conducted to determine the role of lake sediments on water quality, sediment characteristics and metal analysis has been analyzed in the laboratory to determine the concentration of Pb and Zn in the sediment. Metal analysis using Atomic Absorption Spectrophotometry (AAS instrumentation. Sediment characteristics that have analysis, namely physical and chemical parameters are bulk density, density, porosity, water content, texture, pH, DO, colors and others. Sediment sampling locations are Ifale, estuary, Yahim beach and Yoboy with each location in depth of 0-5 cm, 5-10 cm and 10-15 cm vertically. The results showed that at each sampling site and every sediment depths showed highly significant influence on the metal content of Pb and Zn. In general, the deeper the sediment content of Pb and Zn showed different results. Average content of heavy metals (Pb and Zn in sediments at each location that are Ifale at 27.37 mg/Kg and 35.04 mg/Kg, estuary of 15.37 mg/Kg and Pb is 28.01 mg/Kg, Yahim beach of 3.83 mg/Kg and 33.50 mg/Kg, while the location of Yoboy of 6.69 mg/Kg and 34.60 mg/Kg. Concentration of Pb (3.83 to 27.37 mg/Kg and Zn (6.69 to 35.04 mg/Kg in sediments is lower than the standard quality of heavy metals in sediments (EPA Region Va is 40 mg/Kg for Pb and 90 mg/Kg for Zn metals, therefore concentrations of Pb and Zn in sediments at four locations of Sentani lake is still below the quality standard so that the levels of Pb and Zn in the sediment is not contaminated. The existence of Sentani lake sediments act as a reservoir heavy metal and not as a source of pollutants to the water quality in the Sentani lake.

  10. Estimating suspended sediment concentrations in turbid coastal waters of the Santa Barbara Channel with SeaWiFS

    Warrick, J.A.; Mertes, L.A.K.; Siegel, D.A.; Mackenzie, C.

    2004-01-01

    A technique is presented for estimating suspended sediment concentrations of turbid coastal waters with remotely sensed multi-spectral data. The method improves upon many standard techniques, since it incorporates analyses of multiple wavelength bands (four for Sea-viewing Wide Field of view Sensor (SeaWiFS)) and a nonlinear calibration, which produce highly accurate results (expected errors are approximately ±10%). Further, potential errors produced by erroneous atmospheric calibration in excessively turbid waters and influences of dissolved organic materials, chlorophyll pigments and atmospheric aerosols are limited by a dark pixel subtraction and removal of the violet to blue wavelength bands. Results are presented for the Santa Barbara Channel, California where suspended sediment concentrations ranged from 0–200+ mg l−1 (±20 mg l−1) immediately after large river runoff events. The largest plumes were observed 10–30 km off the coast and occurred immediately following large El Niño winter floods.

  11. Changes in the concentration of selected metals in sediments of the River Chotla in northwest Poland in its section affected by various anthropogenic factors

    Włodarczyk Małgorzata

    2015-06-01

    Full Text Available The purpose of the paper was to assess the changes in the concentration of selected metals in the bottom sediment and interstitial water of the River Chotla in northwest Poland. The research was conducted on the river section flowing through Zaspy Małe and a salmonid fish breeding farm. Samples of water and bottom sediment were taken in four control and measurement points, located above and below the village and on a backwater above the trouteries and below the fish breeding ponds. The pH and the concentration of the metals potassium, iron, calcium, manganese and zinc were determined in the water and sediment samples. The lowest concentrations of the metals were found in the samples collected above and below Zaspy Małe, while the highest concentrations of metals in the water and sediment were found in the samples taken in the backwater, above the fish breeding ponds. Exceptions were calcium and potassium, with the highest concentrations of metals in the water being found in the samples taken below the fish breeding ponds. The content of metals in sediments of the analysed section of the River Chotla was mainly determined by the content of organic matter, which varied as it is dependent on water accumulation processes and the operation of nearby fishery facilities. The slightly alkaline pH facilitated long-lasting accumulation of metals in sediments.

  12. Particle size distribution and radioactivity concentration in sea sediment around Kashiwazaki-Kariwa nuclear power station (2)

    As for the sea sediment at 20 points in the range of 2 km offshore in the coastal sea area of Kashiwazaki, between which there is Kashiwazaki-Kariwa Nuclear Power Station, the particle size distribution and the ignition loss were analyzed, and their relations with the radioactivity concentration were investigated. As the result, the soil in the investigated sea area is the sandy soil, in which the particles of 0.063-0.5 mm take 90%, and the ignition loss was about 1%. The range of the concentrations of natural radionuclides, 238U, 232Th and 40K was 10-58, 12-74 and 320-550 Bq/Kg dry, respectively, and the average values were 24, 27 and 450 Bq/Kg dry, respectively. In the concentrations of 238U and 232Th, the positive correlation with the proportion of the particles smaller than 0.125 mm was high, and in 40K, the negative correlation was high. As to artificial radionuclides, 239+240Pu were detected at all the points, and its range of concentration was 0.079-0.42 Bq/Kg dry, and the average value was 0.26 Bq/Kg dry. The relation of these concentrations with the particle size distribution and the ignition loss was not observed. (author)

  13. Uranium hydrogeochemical and stream sediment reconnaissance data release for Saint Johns NTMS quadrangle, Arizona/New Mexico including concentrations of forty-two additional elements

    This report contains data collected during a geochemical survey for uranium in the St. Johns National Topographic Map Series (NTMS) quadrangle of Arizona/New Mexico by the Los Alamos Scientific Laboratory (LASL) as part of the nationwide Hydrogeochemical and Stream Sediment Reconnaissance (HSSR). Totals of 848 water and 1475 sediment samples were collected from 2136 locations in the quadrangle. Histograms and statistical data for uranium concentrations in water and sediment samples and thorium concentrations in sediment samples are given. Listings of the field and uranium data for water samples are given in Appendix I-A. Listings of the field and elemental data for sediment samples are given in Appendix I-B. Uranium/thorium ratios for sediment samples are also included. Appendix II describes standard LASL HSSR field and analytical procedures and explains the codes used in Appendix I. Water samples were initially analyzed for uranium by fluorometry. Water samples collected in 1976 containing more than 10 ppB uranium and those collected in 1979 containing more than 40 ppB uranium were reanalyzed by delayed-neutron counting (DNC). Sediments were analyzed for uranium and thorium as well as aluminum, antimony, barium, beryllium, bismuth, cadmium, calcium, cerium, cesium, chlorine, chromium, cobalt, copper, dysprosium, europium, gold, hafnium, iron, lanthanum, lead, lithium, lutetium, magnesium, manganese, nickel, niobium, potassium, rubidium, samarium, scandium, silver, sodium, strontium, tantalum, terbium, tin, titanium, tungsten, vanadium, ytterbium, and zinc. All sediments were analyzed for uranium by DNC. Other elemental concentrations in sediments were determined by neutron-activation analysis for 31 elements, by x-ray fluorescence for 9 elements, and by arc-source emission spectroscopy for 2 elements. Analytical results for sediments are reported as parts per million

  14. Uranium hydrogeochemical and stream sediment reconnaissance data release for the Billings NTMS Quadrangle, Montana, including concentrations of forty-three additional elements

    This report contains data collected during a geochemical survey for uranium in the Billings quadrangle of south-central Montana. Totals of 1665 water and 1424 sediment samples were collected from 1998 locations in the quadrangle. Histograms and statistical data for uranium concentrations in water and sediment samples and thorium concentrations in sediment samples are given. Elemental concentration, field measurement, weather, geologic, and geographic data for each sample location are listed for waters in Appendix I-A and for sediments in Appendix I-B. Uranium/thorium ratios for sediment samples are also included in Appendix I-B. Appendix II describes standard LASL HSSR field and analytical procedures and explains the codes used in Appendix I. In addition to uranium, waters were analyzed for calcium, chromium, cobalt, copper, iron, lead, magnesium, manganese, molybdenum, nickel, titanium, and zinc (Appendix I-A). Sediments were analyzed for uranium and thorium as well as aluminum, antimony, barium, beryllium, bismuth, cadmium, calcium, cerium, cesium, chlorine, chromium, cobalt, copper, dysprosium, europium, gold, hafnium, iron, lanthanum, lead, lithium, lutetium, magnesium, manganese, nickel, niobium, potassium, rubidium, samarium, scandium, silver, sodium, strontium, tantalum, terbium, tin, titanium, tungsten, vanadium, ytterbium, and zinc (Appendix I-B). All elemental analyzes were performed at the LASL. Water samples delayed neutron counting, and plasma-source emission spectroscopy. Sediments were analyzed by delayed neutron counting, neutron activation analysis, x-ray fluorescence, and arc-source emission spectrography

  15. Geospatial approach towards enumerative analysis of suspended sediment concentration for Ganges-Brahmaputra Bay

    Pandey, P.; Kunte, P.D.

    This study presents an easy, modular, user-friendly, and flexible software package for processing of Landsat 7 ETM and Landsat 8 OLI-TIRS data for estimating suspended particulate matter concentrations in the coastal waters. This package includes 1...

  16. Identification of crystaline sediments in apple juice concentrate with the method of structural rentgenography

    The juice before concentrating was exposed to the pectinolysis and ultrafiltration. The researches to find the causes of coming to being the connection of the calcium with the malic acid are performing. It's supposed that raised quantity of calcium ions in the juice designed to concentration is the effect of pectinolysis. The preparations with low contents of pectinoestherase don't initiate the reaction of calcium precipitation with pectin acid after demethylation

  17. Potential Release Site Sediment Concentrations Correlated to Storm Water Station Runoff through GIS Modeling

    C.T. McLean

    2005-06-01

    This research examined the relationship between sediment sample data taken at Potential Release Sites (PRSs) and storm water samples taken at selected sites in and around Los Alamos National Laboratory (LANL). The PRSs had been evaluated for erosion potential and a matrix scoring system implemented. It was assumed that there would be a stronger relationship between the high erosion PRSs and the storm water samples. To establish the relationship, the research was broken into two areas. The first area was raster-based modeling, and the second area was data analysis utilizing the raster based modeling results and the sediment and storm water sample results. Two geodatabases were created utilizing raster modeling functions and the Arc Hydro program. The geodatabase created using only Arc Hydro functions contains very fine catchment drainage areas in association with the geometric network and can be used for future contaminant tracking. The second geodatabase contains sub-watersheds for all storm water stations used in the study along with a geometric network. The second area of the study focused on data analysis. The analytical sediment data table was joined to the PRSs spatial data in ArcMap. All PRSs and PRSs with high erosion potential were joined separately to create two datasets for each of 14 analytes. Only the PRSs above the background value were retained. The storm water station spatial data were joined to the table of analyte values that were either greater than the National Pollutant Discharge Elimination System (NPDES) Multi-Sector General Permit (MSGP) benchmark value, or the Department of Energy (DOE) Drinking Water Defined Contribution Guideline (DWDCG). Only the storm water stations were retained that had sample values greater than the NPDES MSGP benchmark value or the DOE DWDCG. Separate maps were created for each analyte showing the sub-watersheds, the PRSs over background, and the storm water stations greater than the NPDES MSGP benchmark value or the

  18. Potential Release Site Sediment Concentrations Correlated to Storm Water Station Runoff through GIS Modeling

    This research examined the relationship between sediment sample data taken at Potential Release Sites (PRSs) and storm water samples taken at selected sites in and around Los Alamos National Laboratory (LANL). The PRSs had been evaluated for erosion potential and a matrix scoring system implemented. It was assumed that there would be a stronger relationship between the high erosion PRSs and the storm water samples. To establish the relationship, the research was broken into two areas. The first area was raster-based modeling, and the second area was data analysis utilizing the raster based modeling results and the sediment and storm water sample results. Two geodatabases were created utilizing raster modeling functions and the Arc Hydro program. The geodatabase created using only Arc Hydro functions contains very fine catchment drainage areas in association with the geometric network and can be used for future contaminant tracking. The second geodatabase contains sub-watersheds for all storm water stations used in the study along with a geometric network. The second area of the study focused on data analysis. The analytical sediment data table was joined to the PRSs spatial data in ArcMap. All PRSs and PRSs with high erosion potential were joined separately to create two datasets for each of 14 analytes. Only the PRSs above the background value were retained. The storm water station spatial data were joined to the table of analyte values that were either greater than the National Pollutant Discharge Elimination System (NPDES) Multi-Sector General Permit (MSGP) benchmark value, or the Department of Energy (DOE) Drinking Water Defined Contribution Guideline (DWDCG). Only the storm water stations were retained that had sample values greater than the NPDES MSGP benchmark value or the DOE DWDCG. Separate maps were created for each analyte showing the sub-watersheds, the PRSs over background, and the storm water stations greater than the NPDES MSGP benchmark value or the

  19. Total and methyl mercury concentrations in sediment and water of a constructed wetland in the Athabasca Oil Sands Region.

    Oswald, Claire J; Carey, Sean K

    2016-06-01

    In the Athabasca Oil Sands Region in northeastern Alberta, Canada, oil sands operators are testing the feasibility of peatland construction on the post-mining landscape. In 2009, Syncrude Canada Ltd. began construction of the 52 ha Sandhill Fen pilot watershed, including a 15 ha, hydrologically managed fen peatland built on sand-capped soft oil sands tailings. An integral component of fen reclamation is post-construction monitoring of water quality, including salinity, fluvial carbon, and priority pollutant elements. In this study, the effects of fen reclamation and elevated sulfate levels on mercury (Hg) fate and transport in the constructed system were assessed. Total mercury (THg) and methylmercury (MeHg) concentrations in the fen sediment were lower than in two nearby natural fens, which may be due to the higher mineral content of the Sandhill Fen peat mix and/or a loss of Hg through evasion during the peat harvesting, stockpiling and placement processes. Porewater MeHg concentrations in the Sandhill Fen typically did not exceed 1.0 ng L(-1). The low MeHg concentrations may be a result of elevated porewater sulfate concentrations (mean 346 mg L(-1)) and an increase in sulphide concentrations with depth in the peat, which are known to suppress MeHg production. Total Hg and MeHg concentrations increased during a controlled mid-summer flooding event where the water table rose above the ground surface in most of the fen. The Hg dynamics during this event showed that hydrologic fluctuations in this system exacerbate the release of THg and MeHg downstream. In addition, the elevated SO4(2-) concentrations in the peat porewaters may become a problem with respect to downstream MeHg production once the fen is hydrologically connected to a larger wetland network that is currently being constructed. PMID:27017139

  20. COMPARISON OF HEAVY METAL CONCENTRATIONS IN SURFACE SEDIMENT OF TANJUNG PIAI WETLAND WITH OTHER SITES RECEIVING ANTHROPOGENIC INPUTS ALONG THE SOUTHWESTERN COAST OF PENINSULAR MALAYSIA

    2006-01-01

    Tanjung Piai wetland has now been proclaimed to be a wetland of international importance since 2003. Therefore, its heavy metal pollution status should be known and recorded. In this study, sediments in Tanjung Piai wetland were collected in 2002 and 2005 and were analysed for Cd, Cu, Ni, Pb and Zn. For comparison purpose, sediments were also collected for metal analysis from a known polluted site at Kg. Pasir Puteh, four jetties and a river. A comparison with the polluted sediment collected from Kg. Pasir Puteh and the established Sediment Quality Criteria showed that Tanjung Piai was not polluted with Cd, Cu, Ni, Pb and Zn. These background concentrations or baseline data of heavy metals in the sediment is important for future reference. Therefore, Tanjung Piai wetland is a suitable site for sanctuary and wetland conservation and it should be conserved for its pristine conditions in order to support its high biodiversity.

  1. Bioreduction of iodate in sediment microcosms

    Fabiola Guido-Garcia, Gareth T. W. Law, Jonathan R. Lloyd, Paul Lythgoe; and Katherine Morris

    2015-01-01

    Iodine-129 is a high-yield fission product formed in nuclear reactors and is a risk-driving radionuclide in both contaminated land and radioactive waste disposal due to its high mobility and long half-life. Here, the bioreduction behaviour of iodate was investigated by tracking iodine speciation and concentration in solution during the development of progressive anoxia in sediment microcosm experiments incubated at neutral pH. Experiments with acetate added as an electron donor sh...

  2. Spontaneous concentrations of solids through two-way drag forces between gas and sedimenting particles

    Lambrechts, M.; Johansen, A.; Capelo, H. L.; Blum, J.; Bodenschatz, E.

    2016-06-01

    The behaviour of sedimenting particles depends on the dust-to-gas ratio of the fluid. Linear stability analysis shows that solids settling in the Epstein drag regime would remain homogeneously distributed in non-rotating incompressible fluids, even when dust-to-gas ratios reach unity. However, the nonlinear evolution has not been probed before. Here, we present numerical calculations indicating that, in a particle-dense mixture, solids spontaneously mix out of the fluid and form swarms that are overdense in particles by at least a factor 10. The instability is caused by mass-loaded regions locally breaking the equilibrium background stratification. The driving mechanism depends on nonlinear perturbations of the background flow and shares some similarity to the streaming instability in accretion discs. The resulting particle-rich swarms may stimulate particle growth by coagulation. In the context of protoplanetary discs, the instability could be relevant for aiding small particles to settle to the midplane in the outer disc. Inside the gas envelopes of protoplanets, enhanced settling may lead to a reduced dust opacity, which facilitates the contraction of the envelope. We show that the relevant physical set up can be recreated in a laboratory setting. This will allow our numerical calculations to be investigated experimentally in the future.

  3. Spontaneous concentrations of solids through two-way drag forces between gas and sedimenting particles

    Lambrechts, Michiel; Capelo, Holly L; Blum, Jürgen; Bodenschatz, Eberhard

    2016-01-01

    The behaviour of sedimenting particles depends on the dust-to-gas ratio of the fluid. Linear stability analysis shows that solids settling in the Epstein drag regime would remain homogeneously distributed in non-rotating incompressible fluids, even when dust-to-gas ratios reach unity. However, the non-linear evolution has not been probed before. Here, we present numerical calculations indicating that in a particle-dense mixture solids spontaneously mix out of the fluid and form swarms overdense in particles by at least a factor 10. The instability is caused by mass-loaded regions locally breaking the equilibrium background stratification. The driving mechanism depends on non-linear perturbations of the background flow and shares some similarity to the streaming instability in accretion discs. The resulting particle-rich swarms may stimulate particle growth by coagulation. In the context of protoplanetary discs, the instability could be relevant for aiding small particles to settle to the midplane in the outer...

  4. Assessment of total suspended sediment concentrations in Poyang Lake using HJ-1A/1B CCD imagery

    YU Zhifeng; CHEN Xiaoling; ZHOU Bin; TIAN Liqiao; YUAN Xiaohong; FENG Lian

    2012-01-01

    We explored the potential of the environment and disaster monitoring and forecasting small satellite constellations (HJ-1A/1B satellites) charge-coupled device (CCD) imagery (spatial resolution of 30 m,revisit time of 2 days) in the monitoring of total suspended sediment (TSS) concentrations in dynamic water bodies using Poyang Lake,the largest freshwater lake in China,as an example.Field surveys conducted during October 17-26,2009 showed a wide range of TSS concentration (3-524 mg/L).Atmospheric correction was implemented using the Fast Line-of-sight Atmospheric Analysis of Spectral Hypercubes (FLAASH) module in ENVI with the aid of aerosol information retrieved from concurrent Terra/Moderate Resolution Imaging Spectroradiometer (MODIS) surveys,which worked well at the CCD bands with relatively high reflectance.A practical exponential retrieval algorithm was created between satellite remote sensing reflectance and in-situ measured TSS concentration.The retrieved results for the whole water area matched the in-situ data well at most stations.The retrieval errors may be related to the problem of scale matching and mixed pixel.In three selected subregions of Poyang Lake,the distribution trend of retrieved TSS was consistent with that of the field investigation.It was shown that HJ-1A/1B CCD imagery can be used to estimate TSS concentrations in Poyang Lake over synoptic scales after applying an appropriate atmospheric correction method and retrieval algorithm.

  5. Effect of flexibility on the growth of concentration fluctuations in a suspension of sedimenting fibers: Particle simulations

    Manikantan, Harishankar; Saintillan, David [Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California 92093 (United States)

    2016-01-15

    Three-dimensional numerical simulations are performed to study the stability of a sedimenting suspension of weakly flexible fibers. It is well known that a suspension of rigid rods sedimenting under gravity at low Reynolds number is unstable to concentration fluctuations owing to hydrodynamic interactions. Flexible fibers, however, reorient while settling and even weak flexibility can alter their collective dynamics. In our recent work [Manikantan et al., “The instability of a sedimenting suspension of weakly flexible fibres,” J. Fluid Mech. 756, 935–964 (2014)], we developed a mean-field theory to predict the linear stability of such a system. Here, we verify these predictions using accurate and efficient particle simulations based on a slender-body model. We also demonstrate the mechanisms by which flexibility-induced reorientation alters suspension microstructure, and through it, its stability. Specifically, we first show that the anisotropy of the base state in the case of a suspension of flexible fibers has a destabilizing effect compared to a suspension of rigid rods. Second, a conflicting effect of flexibility is also shown to suppress particle clustering and slow down the growth of the instability. The relative magnitude of filament flexibility and rotational Brownian motion dictates which effect dominates, and our simulations qualitatively follow theoretically predicted trends. The mechanism for either effects is tied to the flexibility-induced reorientation of particles, which we illustrate using velocity and orientation statistics from our simulations. Finally, we also show that, in the case of an initially homogeneous and isotropic suspension, flexibility always acts to suppress the growth of the instability.

  6. Detailed uranium hydrogeochemical and stream sediment reconnaissance data release for the eastern portion of the Montrose NTMS quadrangle, Colorado, including concentrations of forty-five additional elements

    In September and October 1979, the Los Alamos Scientific Laboratory (LASL) conducted a detailed geochemical survey for uranium primarily in the Sawatch Range in the eastern part of the Montrose National Topographic Map Series (NTMS) quadrangle, Colorado, as part of the National Hydrogeochemical and Stream Sediment Reconnaissance (HSSR). This study was done as a follow-up to the uranium reconnaissance previously conducted by the LASL (Broxton et al, 1974). Totals of 1034 water and 2087 sediment samples were collected from streams and springs from 2088 locations within a 5420-km2 area. Statistical data for uranium concentrations in water and sediment samples are tabulated. Elemental concentration, field measurement, weather, geologic, and geographic data for each sample location are listed for waters in and for sediments in appendices. This report contains uranium analyses for water samples and multielement analyses for sediment samples. Sediments were analyzed for uranium and thorium as well as aluminum, antimony, arsenic, barium, beryllium, bismuth, cadmium, calcium, cerium, cesium, chlorine, chromium, cobalt, copper, dysprosium, europium, gold, hafnium, iron, lanthanum, lead, lithium, lutetium, magnesium, manganese, nickel, niobium, potassium, rubidium, samarium, scandium, selenium, silver, sodium, strontium, tantalum, terbium, tin, titanium, tungsten, vanadium, ytterbium, zinc, and zirconium. All elemental analyses were performed at the LASL. Water samples were analyzed for uranium by fluorometry and are reported as parts per billion. Sediments were analyzed for uranium by delayed neutron counting. Other elemental concentrations in sediments were determined by neutron activation analysis for 31 elements, by x-ray fluorescence for 12 elements, and by arc-source emission spectrography for 2 elements. Analytical results for sediments are reported as parts per million

  7. Fate of polychlorinated biphenyls in a contaminated lake ecosystem: combining equilibrium passive sampling of sediment and water with total concentration measurements of biota.

    Mäenpää, Kimmo; Leppänen, Matti T; Figueiredo, Kaisa; Mayer, Philipp; Gilbert, Dorothea; Jahnke, Annika; Gil-Allué, Carmen; Akkanen, Jarkko; Nybom, Inna; Herve, Sirpa

    2015-11-01

    Equilibrium sampling devices can be applied to study and monitor the exposure and fate of hydrophobic organic chemicals on a thermodynamic basis. They can be used to determine freely dissolved concentrations and chemical activity ratios and to predict equilibrium partitioning concentrations of hydrophobic organic chemicals in biota lipids. The authors' aim was to assess the equilibrium status of polychlorinated biphenyls (PCBs) in a contaminated lake ecosystem and along its discharge course using equilibrium sampling devices for measurements in sediment and water and by also analyzing biota. The authors used equilibrium sampling devices (silicone rubber and polyethylene [PE]) to determine freely dissolved concentrations and chemical activities of PCBs in the water column and sediment porewater and calculated for both phases the corresponding equilibrium concentrations and chemical activities in model lipids. Overall, the studied ecosystem appeared to be in disequilibrium for the studied phases: sediment, water, and biota. Chemical activities of PCBs were higher in sediment than in water, which implies that the sediment functioned as a partitioning source of PCBs and that net diffusion occurred from the sediment to the water column. Measured lipid-normalized PCB concentrations in biota were generally below equilibrium lipid concentrations relative to the sediment (CLip ⇌Sed ) or water (CLip ⇌W ), indicating that PCB levels in the organisms were below the maximum partitioning levels. The present study shows the application versatility of equilibrium sampling devices in the field and facilitates a thermodynamic understanding of exposure and fate of PCBs in a contaminated lake and its discharge course. PMID:26053463

  8. Denitrification activity is closely linked to the total ambient Fe concentration in mangrove sediments of Goa, India

    Fernandes, Sheryl Oliveira; Gonsalves, Maria-Judith; Michotey, Valérie D.; Bonin, Patricia C.; Loka, A.; Bharathi, P.

    2013-10-01

    Denitrification activity (DNT) and associated environmental parameters were examined in two mangrove ecosystems of Goa, India - the relatively unimpacted Tuvem and the anthropogenically-influenced Divar. Sampling was carried out at every 2 cm interval within the 0-10 cm depth range to determine (1) seasonal (pre-monsoon, monsoon and post-monsoon) down-core variation in DNT (2) assess the environmental factors influencing the DNT and (3) to build predictive models for benthic DNT. Denitrification generally decreased with depth and showed marked seasonal variation at both the locations. Denitrification peaked during the pre-monsoon occurring at a rate of up to 21.00 ± 12.84 nmol N2O g-1 h-1 within 0-4 cm at both the locations. Further, DNT at pre-monsoon was significantly influenced by Fe content at Tuvem and Divar suggesting Fe-mediated nitrate respiration. The influence of other limiting substrates such as NO3- and NO2- was most important during the monsoon and post-monsoon especially at Divar. The multiple regression models developed could predict 67-98% of the observed variability in DNT through the seasons. About 6-9 environmental variables were required to relatively well-predict DNT in these sediments with the complexity governing DNT decreasing from pre-monsoon to post-monsoon. Our results reveal that seasonal dynamics of DNT in tropical mangrove sediments are closely linked to the total Fe at the prevailing ambient concentration in both the systems.

  9. COMPARISON OF TWO 4.7-MILLIGRAM TO ONE 9.4-MILLIGRAM DESLORELIN ACETATE IMPLANTS ON EGG PRODUCTION AND PLASMA PROGESTERONE CONCENTRATIONS IN JAPANESE QUAIL (COTURNIX COTURNIX JAPONICA).

    Petritz, Olivia A; Guzman, David Sanchez-Migallon; Hawkins, Michelle G; Kass, Philip H; Conley, Alan J; Paul-Murphy, Joanne

    2015-12-01

    Reproductive disease in captive avian species is common, and medical management is often chosen over surgical removal of the reproductive tract. In a previous study with Japanese quail, a single 4.7-mg deslorelin acetate implant reversibly decreased egg production in 6 out 10 birds for 70 days. The objective of the current study was to evaluate the effects of two 4.7-mg deslorelin acetate implants versus one 9.4-mg implant on egg production and plasma progesterone concentrations in Japanese quail ( Coturnix coturnix japonica). Following a 10-day period of consistent egg laying, 30 adult female Japanese quail were anesthetized and received two 4.7-mg deslorelin implants (n = 10), one 9.4-mg deslorelin implant (n = 10), or a single, identical placebo implant (n = 10) s.c. between the scapulae. Egg production was monitored daily, and plasma progesterone concentrations were measured on days 0, 14, 29, 120, 148, and 182 via enzyme-linked immunoassay. All birds were weighed periodically and euthanized at day 182, after which their reproductive tracts were evaluated at gross necropsy. Seven out of 10 birds treated with two 4.7-mg implants ceased egg laying 1 wk after implantation and remained nonovulatory for approximately 100 days. Cessation of egg laying for the 9.4-mg treatment group occurred in 7 out of 10 birds; onset was variable (weeks 5-12) and continued for the remainder of the study period. Plasma progesterone concentrations for deslorelin treatment groups were not significantly different compared to the placebo group at any time point. In conclusion, the two 4.7-mg and the one 9.4-mg implant treatments ceased egg laying in a similar number of birds, but the 9.4-mg implant had a slower onset of action and the effects on egg laying were inconsistent throughout the study period. Further studies evaluating use of deslorelin acetate in other avian species are needed. PMID:26667535

  10. Uranium hydrogeochemical and stream sediment reconnaissance data release for the Rock Springs NTMS Quadrangle, Wyoming, including concentrations of forty-two additional elements

    This report contains data collected by the Los Alamos Scientific Laboratory (LASL) during a regional geochemical survey for uranium in the Rock Springs National Topographic Map Series (NTMS) quadrangle, southwestern Wyoming, as part of the nationwide hydrogeochemical and Stream Sediment Reconnaissance (HSSR). Totals of 397 water and 1794 sediment samples were collected from 1830 locations in the Rock Springs quadrangle of southern Wyoming during the summer of 1976. The average uranium concentration of all water samples is 6.57 ppb and the average sediment uranium concentration is 3.64 ppM. Elemental concentration, field measurement, weather, geologic, and geographic data for each sample location are listed for waters and for sediments in the appendices. Uranium/thorium ratios for sediment samples are also included. A sample location overlay (Plate I) at 1:250 000 scale for use in conjunction with the Rock Springs NTMS quadrangle sheet (US Geological Survey, 1954) is provided. All elemental analyses were performed at the LASL. Water samples were initially analyzed for uranium by fluorometry. All water samples containing more than 40 ppB uranium were reanalyzed by delayed-neutron counting. Sediments were analyzed for uranium and thorium as well as Al, Sb, Ba, Be, Bi, Cd, Ca, Ce, Cs, Cl, Cr, Co, Cu, Dy, Eu, Au, Hf, Fe, La, Pb, Li, Lu, Mg, Mn, Ni, Nb, K, Rb, Sm, Sc, Ag, Na, Sr, Ta, Tb, Sn, T, W, V, Yb, and Zn. All sediments were analyzed for uranium by delayed-neutron counting. Other elemental concentrations in sediments were determined by neutron-activation analysis for 30 elements, by x-ray fluorescence for 12 elements, and by arc-source emission spectrography for 2 elements. These analytical methods are described briefly in the appendix. This report is simply a data release and is intended to make the data available to the DOE and to the public as quickly as possible

  11. Uranium hydrogeochemical and stream sediment reconnaissance data release for the Rock Springs NTMS quadrangle, Wyoming, including concentrations of forty-two additional elements

    Totals of 397 water and 1794 sediment samples were collected from 1830 locations in the Rock Springs quadrangle of southern Wyoming during the summer of 1976. Water samples were collected from 230 streams, 123 springs, 28 wells, and 16 artificial ponds. Sediment samples were collected from 231 wet streams and 1389 dry streams, 119 wet springs and 8 dry springs 29 artificial ponds and 18 natural ponds. The average uranium concentration of all water samples if 6.57 ppB and the average sediment uranium concentration is 3.64 ppM. Elemental concentration, field measurement, weather, geologic, and geographic data for each sample location are listed for waters and for sediments in Appendices. Uranium/thorium ratios for sediment samples are also included. All elemental analyses were performed at the LASL. Water samples were initially analyzed for uranium by fluorometry. All water samples containing more than 40 ppB uranium were reanalyzed by delayed-neutron counting (DNC). Sediments were analyzed for uranium and thorium as well as aluminum, antimony, barium, beryllium, bismuth, cadmium, calcium, cerium, cesium, chlorine, chromium, cobalt, copper, dysprosium, europium, gold, hafnium, iron, lanthanum, lead, lithium, lutetium, magnesium, manganese, nickel, niobium, potassium, rubidium, samarium, scandium, silver, sodium, strontium, tantalum, terbium, tin, titanium, tungsten, vanadium, ytterbium, and zinc. All sediments were analyzed for uranium by delayed-neutron counting. Other elemental concentrations in sediments were determined by neutron-activation analysis for 30 elements by x-ray fluorescence for 12 elements, and by arc-source emission spectrography for 2 elements. These analytical methods are described briefly

  12. A Seasonally Robust Empirical Algorithm to Retrieve Suspended Sediment Concentrations in the Scheldt River

    Dries Raymaekers

    2010-08-01

    Full Text Available A seasonally robust algorithm for the retrieval of Suspended Particulate Matter (SPM in the Scheldt River from hyperspectral images is presented. This algorithm can be applied without the need to simultaneously acquire samples (from vessels and pontoons. Especially in dynamic environments such as estuaries, this leads to a large reduction of costs, both in equipment and personnel. The algorithm was established empirically using in situ data of the water-leaving reflectance obtained over the tidal cycle during different seasons and different years. Different bands and band combinations were tested. Strong correlations were obtained for exponential relationships between band ratios and SPM concentration. The best performing relationships are validated using airborne hyperspectral data acquired in June 2005 and October 2007 at different moments in the tidal cycle. A band ratio algorithm (710 nm/596 nm was successfully applied to a hyperspectral AHS image of the Scheldt River to obtain an SPM concentration map.

  13. Acyclic archaebacterial ether lipids in swamp sediments

    Pauly, George G.; Van Vleet, Edward S.

    1986-06-01

    Acyclic phytanyl diether glycerol and biphytanyl ether lipids have been quantified in two modern swamp sediment cores in concentrations ranging up to 360 μg/ml porewater. Methanogenic bacteria are the only known source organisms which can inhabit the swamp sediments. Variations in relative abundance between these lipids may reflect taxonomic changes in methanogen populations or the stage of growth. Maxima in methanogen lipid concentrations coincide with local maxima of 13C of organic matter, possibly the result of a pool effect on CO 2 or acetate. Methane production estimates calculated from lipid concentrations in swamp sediments range from 0.1 to 1.3 mmol cm -2 yr -1, values which are consistent with published methane fluxes.

  14. Suspended sediment concentration mapping based on the MODIS satellite imagery in the East China inland, estuarine, and coastal waters

    Yang, Xianping; Sokoletsky, Leonid; Wei, Xiaodao; Shen, Fang

    2016-04-01

    The purpose of this research is to improve the retrieval accuracy for the suspended sediment concentration (SSC) from in situ and satellite remote sensing measurements in turbid East China estuarine and coastal waters. For this aim, three important tasks are formulated and solved: 1) an estimation of remote-sensing reflectance spectra R rs(λ) after atmospheric correction; 2) an estimation of R rs(λ) from the radiometric signals above the air-water surface; and 3) an estimation of SSC from R rs(λ). Six different models for radiometric R rs(λ) determination and 28 models for SSC versus R rs(λ) are analyzed based on the field observations made in the Changjiang River estuary and its adjacent coastal area. The SSC images based on the above-mentioned analysis are generated for the area.

  15. The effects of wind and rainfall on suspended sediment concentration related to the 2004 Indian Ocean tsunami

    The effects of rainfall and wind speed on the dynamics of suspended sediment concentration (SSC), during the 2004 Indian Ocean tsunami, were analyzed using spatial statistical models. The results showed a positive effect of wind speed on SSC, and inconsistent effects (positive and negative) of rainfall on SSC. The effects of wind speed and rainfall on SSC weakened immediately around the tsunami, indicating tsunami-caused floods and earthquake-induced shaking may have suddenly disturbed the ocean-atmosphere interaction processes, and thus weakened the effects of wind speed and rainfall on SSC. Wind speed and rainfall increased markedly, and reached their maximum values immediately after the tsunami week. Rainfall at this particular week exceeded twice the average for the same period over the previous 4 years. The tsunami-affected air-sea interactions may have increased both wind speed and rainfall immediately after the tsunami week, which directly lead to the variations in SSC.

  16. Comparing sediment equilibrium partitioning and passive sampling techniques to estimate benthic biota PCDD/F concentrations in Newark Bay, New Jersey (U.S.A.)

    Sediment and polyethylene sampler-based estimates of polychlorinated dibenzo-p-dioxin/dibenzofuran (PCDD/F) concentrations in Newark Bay, New Jersey (USA) benthic biota were compared. Biota concentrations based on sediment were estimated using an organic carbon (OC)-water partitioning model and an OC and black carbon (BC)-water dual model. Biota concentrations based on polyethylene were estimated from samplers deployed in the Newark Bay water column and samplers immersed in a sediment/porewater slurry in the laboratory. Porewater samplers provided the best estimates of biota concentrations (within 3.1×), with best results achieved for deposit-feeders (within 1.6×). Polyethylene deployed in deep water also provided good estimates of biota concentrations (within 4×). By contrast, OC-water partitioning overestimated biota concentrations by up to 7×, while OC and BC combined underestimated biota concentrations by up to 13×. We recommend passive samplers such as polyethylene for estimating concentrations of hydrophobic organic contaminants in field biota given its simplicity and relatively lower uncertainty compared to sediment equilibrium partitioning. -- Highlights: • PE samplers accurately estimate Newark Bay biota PCDD/F concentrations. • A traditional KOC partitioning model overestimated PCDD/F uptake by a factor of 4–7. • A dual KOC and KBC model underestimated biota PCDD/F uptake by a factor of 4–13. • Sediment- and depth-specific KBCs improved predictions of PCDD/F uptake. • Deposit feeder uptake switches from porewater control to ingestion at log KOW 6–7. -- Using polyethylene samplers to measure porewater concentrations is a more efficient approach for estimating site-specific bioavailable organic contaminants than equilibrium partitioning

  17. Tracing euxinia by molybdenum concentrations in sediments using handheld X-ray fluorescence spectroscopy (HHXRF)

    Dahl, Tais W.; Ruhl, Micha; Hammarlund, Emma U.;

    2013-01-01

    sigma) after a daily calibration to samples covering a range of Mo concentrations from 0 to >30 ppm. Hand-held XRF equipment also allows Mo measurements directly on fresh rock surfaces, both in the field and under laboratory conditions. Rock-samples from a Cambrian drill core closely match ICPMS...... levels is, however, expensive and cannot be directly performed in the field. Here, we show that handheld x-ray absorption spectroscopy (HHXRF) on both rock-powders and rock surfaces provides a powerful tool for laboratory or field-based, geochemical characterization of Mo content and the tracing of...

  18. Bioaccumulation of native polycyclic aromatic hydrocarbons from sediment by a polychaete and a gastropod: freely dissolved concentrations and activated carbon amendment.

    Cornelissen, Gerard; Breedveld, Gijs D; Naes, Kristoffer; Oen, Amy M P; Ruus, Anders

    2006-09-01

    The present paper describes a study on the bioaccumulation of native polycyclic aromatic hydrocarbons (PAHs) from three harbors in Norway using the polychaete Nereis diversicolor and the gastropod Hinia reticulata. First, biota-sediment accumulation factors (BSAFs) were measured in laboratory bioassays using the original sediments. Median BSAFs were 0.004 to 0.01 kg organic carbon/kg lipid (10 PAHs and 6 organism-sediment combinations), which was a factor of 89 to 240 below the theoretical BSAF based on total sediment contents (which is approximately one). However, if BSAFs were calculated on the basis of measured freely dissolved PAH concentrations in the pore water (measured with polyoxymethylene passive samplers), it appeared that these BSAFfree values agreed well with the measured BSAFs, within a factor of 1.7 to 4.3 (median values for 10 PAHs and six organism-sediment combinations). This means that for bioaccumulation, freely dissolved pore-water concentrations appear to be a much better measure than total sediment contents. Second, we tested the effect of 2% (of sediment dry wt) activated carbon (AC) amendments on BSAE The BSAFs were significantly reduced by a factor of six to seven for N. diversicolor in two sediments (i.e., two of six organism-sediment combinations), whereas no significant reduction was observed for H. reticulata. This implies that either site-specific evaluations of AC amendment are necessary, using several site-relevant benthic organisms, or that the physiology of H. reticulata caused artifactually high BSAF values in the presence of AC. PMID:16986789

  19. Long-term trends of 137Cs concentrations in marine biota, sediments and seawater in the coastal seas in the vicinity of nuclear power plants in Japan

    The results of the long-term trend analyses of the 137Cs data obtained during the marine environmental radioactivity monitoring program sponsored by the Ministry of Education, Culture, Sports, Science and Technology and carried out from 1983 to 2000 by the Marine Ecology Research Institute are presented. In 86.8% of the marine biota, 75.6% of the sediments, 100% of the surface seawater and 91.1% of the bottom seawater, a statistically significant decrease of 137Cs concentrations was observed. The 137Cs concentrations in the bottom seawater and sediments below the depth of 200 m decreased more slowly than those above the 200 m depth. The 137Cs concentrations in the marine biota, surface seawater, and bottom seawater and sediments above 200 m decreased by similar annual rates of 0.039, 0.041, 0.045 and 0.041 year-1, respectively. Those of the bottom seawater and sediments below the 200 m depth (200∼500 m) decreased by the rates of 0.025 and 0.026 year-1, respectively. These results suggest that an equilibrium in 137Cs concentrations in the seawater and sediments, including the marine biota above the 200 m depth, is attained both above and below the depth of 200 m. (author)

  20. Spatial distribution and concentration assessment of total petroleum hydrocarbons in the intertidal zone surface sediment of Todos os Santos Bay, Brazil.

    Silva, Carine S; Moreira, Icaro T A; de Oliveira, Olivia M C; Queiroz, Antonio F S; Garcia, Karina S; Falcão, Brunno A; Escobar, Narayana F C; Rios, Mariana Cruz

    2014-02-01

    The primary objective of this study was to investigate the concentrations and spatial distribution of the total petroleum hydrocarbons (TPHs) in the intertidal zone surface sediment of Todos os Santos Bay, Brazil, to assess the distribution and degree of contamination by TPHs, measure the level of TPH degradation in the surface sediment, and identify the organic matter sources. The surface sediment used in this study was collected in 50 stations, and TPHs, isoprenoid alkanes (pristane and phytane), and unresolved complex mixture (UCM) were analyzed by gas chromatography with a flame ionization detector. The total concentrations ranged from 0.22 to 40,101 μg g(-1) dry weight and showed a strong correlation with the total organic carbon (TOC) content. The highest TPH concentrations were observed in samples from the mangrove sediments of a river located near a petroleum refinery. Compared with other studies in the world, the TPH concentrations in the intertidal surface sediment of Todos os Santos Bay were below average in certain stations and above average in others. An analysis of the magnitude of UCM (0.11 to 17,323 μg g(-1) dry weight) and the ratios nC17/Pr and nC18/Ph suggest that an advanced state of oil weathering, which indicates previous contamination. The molar C/N ratios varied between 5 and 43, which indicate organic matter with a mixed origin comprising marine and continental contributions. PMID:24100798

  1. Suspended-sediment concentrations, loads, total suspended solids, turbidity, and particle-size fractions for selected rivers in Minnesota, 2007 through 2011

    Ellison, Christopher A.; Savage, Brett E.; Johnson, Gregory D.

    2014-01-01

    Sediment-laden rivers and streams pose substantial environmental and economic challenges. Excessive sediment transport in rivers causes problems for flood control, soil conservation, irrigation, aquatic health, and navigation, and transports harmful contaminants like organic chemicals and eutrophication-causing nutrients. In Minnesota, more than 5,800 miles of streams are identified as impaired by the Minnesota Pollution Control Agency (MPCA) due to elevated levels of suspended sediment. The U.S. Geological Survey, in cooperation with the MPCA, established a sediment monitoring network in 2007 and began systematic sampling of suspended-sediment concentrations (SSC), total suspended solids (TSS), and turbidity in rivers across Minnesota to improve the understanding of fluvial sediment transport relations. Suspended-sediment samples collected from 14 sites from 2007 through 2011 indicated that the Zumbro River at Kellogg in the driftless region of southeast Minnesota had the highest mean SSC of 226 milligrams per liter (mg/L) followed by the Minnesota River at Mankato with a mean SSC of 193 mg/L. During the 2011 spring runoff, the single highest SSC of 1,250 mg/L was measured at the Zumbro River. The lowest mean SSC of 21 mg/L was measured at Rice Creek in the northern Minneapolis- St. Paul metropolitan area. Total suspended solids (TSS) have been used as a measure of fluvial sediment by the MPCA since the early 1970s; however, TSS concentrations have been determined to underrepresent the amount of suspended sediment. Because of this, the MPCA was interested in quantifying the differences between SSC and TSS in different parts of the State. Comparisons between concurrently sampled SSC and TSS indicated significant differences at every site, with SSC on average two times larger than TSS concentrations. The largest percent difference between SSC and TSS was measured at the South Branch Buffalo River at Sabin, and the smallest difference was observed at the Des Moines

  2. Uranium hydrogeochemical and stream sediment reconnaissance data release for the Dubois NTMS Quadrangle, Idaho/Montana, including concentrations of forty-five additional elements

    Totals of 1024 water samples and 1600 sediment samples were collected from 1669 locations in the Dubois quadrangle. Water samples were taken at streams, springs, and wells; sediment samples were collected from streams and springs. All field and analytical data are presented for waters in Appendix I-A and for sediments in I-B. All elemental analyses were performed at the LASL. Water samples were initially analyzed for uranium by fluorometry. All water samples containing more than the upper detection limit of uranium were reanalyzed by delayed neutron counting. Sediments were analyzed for uranium and thorium as well as aluminum, antimony, arsenic, barium, beryllium, bismuth, cadmium, calcium, cerium, cesium, chlorine, chromium, cobalt, copper, dysprosium, europium, gold, hafnium, iron, lanthanum, lead, lithium, lutetium, magnesium, manganese, nickel, niobium, potassium rubidium, samarium, scandium, selenium, silver, sodium, strontium, tantalum, terbium, tin, titanium, tungsten, vanadium, ytterbium, zinc and zirconium. All sediments were analyzed for uranium by delayed-neutron counting. Other elemental concentrations in sediments were determined by neutron-activation analysis for 30 elements, by x-ray fluorescence for 12 elements, and by arc-source emission spectrography for 2 elements. Analytical results for sediments are reported as parts per million

  3. Uranium concentrations in stream waters and sediments from selected sites in the eastern Seward Peninsula, Koyukuk, and Charley River areas, and across South-Central Alaska

    Sharp, R.R. Jr.; Hill, D.E.

    1978-04-01

    During the summer of 1975, a 6-week reconnaissance was conducted in widespread areas of Alaska as part of the National Uranium Resource Evaluation (NURE) program; Water, stream sediment, and bedrock samples were taken from the eastern Seward Peninsula, from north of Koyukuk River, from the Charley River area, and from across south central Alaska. This report contains the LASL uranium determinations resulting from fluorometric analysis of the water samples and delayed-neutron counting of the stream sediment samples. Results of total uranium for 611 water and 641 sediment samples, from 691 stream locations, are presented. Overlays showing the numbered sample locations and graphically portraying the concentrations of uranium in water and stream sediment samples, at 1:250,000 scale for use with existing National Topographic Map Series (NTMS) sheets and published geologic maps, are provided as plates. The main purposes of this work are to make the uranium data available to the public in the standard computer format used in the NURE Hydrogeochemical and Stream Sediment Reconnaissance (i.e., with a DOE sample number giving the latitude and longitude of each sample location) and to provide uranium concentration overlays at the standard scale of 1:250,000 adopted by the DOE for the NURE program. It also allows a plausible explanation of differences between the uranium values for sediment as determined by acid dissolution/extraction/fluorometry and by delayed-neutron counting that were noted in the earlier report.

  4. Uranium concentrations in stream waters and sediments from selected sites in the eastern Seward Peninsula, Koyukuk, and Charley River areas, and across South-Central Alaska

    During the summer of 1975, a 6-week reconnaissance was conducted in widespread areas of Alaska as part of the National Uranium Resource Evaluation (NURE) program; Water, stream sediment, and bedrock samples were taken from the eastern Seward Peninsula, from north of Koyukuk River, from the Charley River area, and from across south central Alaska. This report contains the LASL uranium determinations resulting from fluorometric analysis of the water samples and delayed-neutron counting of the stream sediment samples. Results of total uranium for 611 water and 641 sediment samples, from 691 stream locations, are presented. Overlays showing the numbered sample locations and graphically portraying the concentrations of uranium in water and stream sediment samples, at 1:250,000 scale for use with existing National Topographic Map Series (NTMS) sheets and published geologic maps, are provided as plates. The main purposes of this work are to make the uranium data available to the public in the standard computer format used in the NURE Hydrogeochemical and Stream Sediment Reconnaissance (i.e., with a DOE sample number giving the latitude and longitude of each sample location) and to provide uranium concentration overlays at the standard scale of 1:250,000 adopted by the DOE for the NURE program. It also allows a plausible explanation of differences between the uranium values for sediment as determined by acid dissolution/extraction/fluorometry and by delayed-neutron counting that were noted in the earlier report

  5. Impact of Hurricane Irene on Vibrio vulnificus and Vibrio parahaemolyticus concentrations in surface water, sediment and cultured oysters in the Chesapeake Bay, Maryland, USA

    KristiSShaw

    2014-05-01

    Full Text Available To determine if a storm event (i.e., high winds, large volumes of precipitation could alter concentrations of Vibrio vulnificus and Vibrio parahaemolyticus in aquacultured oysters (Crassostrea virginica and associated surface water and sediment, this study followed a sampling timeline before and after Hurricane Irene impacted the Chesapeake Bay estuary in late August 2011. Aquacultured oysters were sampled from two levels in the water column: surface 0.3 m and near-bottom just above the sediment. Concentrations of each Vibrio spp. and associated virulence genes were measured in oysters with a combination of real-time PCR and most probable number enrichment methods, and in sediment and surface water with real-time PCR. While concentration shifts of each Vibrio species were apparent post-storm, statistical tests indicated no significant change in concentration change for either Vibrio species by location (surface or near bottom oysters or date sampled (oyster tissue, surface water and sediment concentrations. V. vulnificus in oyster tissue was correlated with total suspended solids (r=0.41, p=0.04, and V. vulnificus in sediment was correlated with secchi depth (r=-0.93, p< 0.01, salinity (r=-0.46, p=0.02, tidal height (r=-0.45, p=0.03, and surface water V. vulnificus (r=0.98, p< 0.01. V. parahaemolyticus in oyster tissue did not correlate with environmental measurements, but V. parahaemolyticus in sediment and surface water correlated with several measurements including secchi depth (r=-0.48, p=0.02[sediment]; r=-0.97 p< 0.01[surface water] and tidal height (r=-0.96. p< 0.01[sediment], r=-0.59,p< 0.01 [surface water]. The concentrations of Vibrio spp. were higher in oysters relative to other studies (average V. vulnificus 4x105 MPN g-1, V. parahaemolyticus 1x105 MPN g-1, and virulence-associated genes were detected in most oyster samples. This study provides a first estimate of storm-related Vibrio density changes in oyster tissues, sediment and

  6. Concentrations and loads of suspended sediment-associated pesticides in the San Joaquin River, California and tributaries during storm events

    Hladik, M.L.; Domagalski, J.L.; Kuivila, K.M.

    2009-01-01

    Current-use pesticides associated with suspended sediments were measured in the San Joaquin River, California and its tributaries during two storm events in 2008. Nineteen pesticides were detected: eight herbicides, nine insecticides, one fungicide and one insecticide synergist. Concentrations for the herbicides (0.1 to 3000 ng/g; median of 6.1 ng/g) were generally greater than those for the insecticides (0.2 to 51 ng/g; median of 1.5 ng/g). Concentrations in the tributaries were usually greater than in the mainstem San Joaquin River and the west side tributaries were higher than the east side tributaries. Estimated instantaneous loads ranged from 1.3 to 320 g/day for herbicides and 0.03 to 53 g/day for insecticides. The greatest instantaneous loads came from the Merced River on the east side. Instantaneous loads were greater for the first storm of 2008 than the second storm in the tributaries while the instantaneous loads within the San Joaquin River were greater during the second storm. Pesticide detections generally reflected pesticide application, but other factors such as physical-chemical properties and timing of application were also important to pesticide loads.

  7. Concentrations and chemical forms of potentially toxic metals in road-deposited sediments from different zones of Hangzhou, China

    ZHANG Mingkui; WANG Hao

    2009-01-01

    The 25 road-deposited sediments were collected from five different land-use zones (industrial, residential, commercial, park, and countryside) in Hangzhou, China. The concentrations of metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in these samples were determined using the ICP-AES after digestion with the mixture of HNO3-HF-HCl (aqua regia), and chemically fractionated using the modified BCR (the European Community Bureau of Reference) sequential extraction procedure. The highest metal concentration level was detected in the sample from industrial zone and commercial zone having heavy traffic. While the lowest metal level was noted in the street dust sample from residential zone, park, and countryside zone. The mobility sequence based on the sum of the BCR sequential extraction stages was: Zn (80.28%), Pb (78.68%), Cd (77.66%) > Cu (73.34%) > Mn (67.92%) > Co (41.66%) > Ni (30.36%) > Cr (21.56%), Fe (20.86%). Correlation analysis and principal component analysis were applied to the data matrix to evaluate the analytical results and to identify the possible pollution sources of metals. Factor analysis showed that these areas were mainly contaminated by three sources, namely lithology, traffic, and industry.

  8. Concentration profiles for fine and coarse sediments suspended by waves over ripples: An analytical study with the 1-DV gradient diffusion model

    Absi, Rafik

    2010-01-01

    Field and laboratory measurements of suspended sediments over wave ripples show, for time-averaged concentration profiles in semi-log plots, a contrast between upward convex profiles for fine sand and upward concave profiles for coarse sand. Careful examination of experimental data for coarse sand shows a near-bed upward convex profile beneath the main upward concave profile. Available models fail to predict these two profiles for coarse sediments. The 1-DV gradient diffusion model predicts the main upward concave profile for coarse sediments thanks to a suitable $\\beta$(y)-function (where $\\beta$ is the inverse of the turbulent Schmidt number and y is the distance from the bed). In order to predict the near-bed upward convex profile, an additional parameter {\\alpha} is needed. This parameter could be related to settling velocity ($\\alpha$ equal to inverse of dimensionless settling velocity) or to convective sediment entrainment process. The profiles are interpreted by a relation between second derivative of ...

  9. Suspended sediment concentration in the Lower Sea Scheldt (Belgium): long term trends and relation to mud disposal

    Depreiter, Davy; van Holland, Gijsbert; Lanckriet, Thijs; Beirinckx, Kirsten; Vanlede, Joris; Maris, Tom

    2015-04-01

    In this presentation, results from different monitoring and research projects (OMES, MONEOS, Flexible Disposal and Marine-Fluvial mud ratio) will be integrated to increase the insight in the trends and relation between mud disposal and the increasing sediment concentrations (SSC) in the Lower Sea Scheldt. In the Scheldt Estuary, major projects have been carried out in the past decade, among which the third deepening of the navigation channel and the opening of the Deurganck dock. Maintenance dredging is carried out to guarantee a minimum navigation depth. A rising trend in the volume of mud dredged in the Lower Sea Scheldt is observed since 2006, the year after the opening of the Deurganck Dock. The trend is explained by increasing mud volumes dredged in this dock and on a nearby sill. This volume culminated in 2011 (4.8 million m³) when the depth of this dock was increased to its design depth. The dredged mud is disposed upstream, quickly to be resuspended. Near the mud disposal location, yearly averaged SSC (measured at 4.5 m above bed) tripled between 2005 and 2011 (108 to 348 mg/L), and SSC peaks increased even stronger. A multivariate regression model indicated a strong correlation between mud disposal volumes and timing and observed SSC. Mud disposal volumes and SSC where somewhat lower again after 2011. The SSC increase raises an alert with regard to the risk for a regime shift towards a hyperturbid system. Increasing SSC may indeed decrease the hydraulic resistance initiating a feedback mechanism that results in further increasing SSC values. It thus appears that more mud is being circulated: the Deurganck dock acts as mud sink, from which the mud is - after dredging and disposal - resuspended. The mud may have different sources: fluvial or marine influx. The increasing SSC might not only be related to the mud disposal, but also to changing tidal characteristics that enhance the influx of marine suspended sediments. To elucidate this, an analysis of the

  10. Empirical models for estimating the suspended sediment concentration in Amazonian white water rivers using Landsat 5/TM

    Montanher, Otávio C.; Novo, Evlyn M. L. M.; Barbosa, Cláudio C. F.; Rennó, Camilo D.; Silva, Thiago S. F.

    2014-06-01

    Suspended sediment yield is a very important environmental indicator within Amazonian fluvial systems, especially for rivers dominated by inorganic particles, referred to as white water rivers. For vast portions of Amazonian rivers, suspended sediment concentration (SSC) is measured infrequently or not at all. However, remote sensing techniques have been used to estimate water quality parameters worldwide, from which data for suspended matter is the most successfully retrieved. This paper presents empirical models for SSC retrieval in Amazonian white water rivers using reflectance data derived from Landsat 5/TM. The models use multiple regression for both the entire dataset (global model, N = 504) and for five segmented datasets (regional models) defined by general geological features of drainage basins. The models use VNIR bands, band ratios, and the SWIR band 5 as input. For the global model, the adjusted R2 is 0.76, while the adjusted R2 values for regional models vary from 0.77 to 0.89, all significant (p-value < 0.0001). The regional models are subject to the leave-one-out cross validation technique, which presents robust results. The findings show that both the average error of estimation and the standard deviation increase as the SSC range increases. Regional models were more accurate when compared with the global model, suggesting changes in optical proprieties of water sampled at different sampling stations. Results confirm the potential for the estimation of SSC from Landsat/TM historical series data for the 1980s and 1990s, for which the in situ database is scarce. Such estimates supplement the SSC temporal series, providing a more comprehensive SSC temporal series which may show environmental dynamics yet unknown.

  11. Phase Preference by Active, Acetate-Utilizing Bacteria at the Rifle, CO Integrated Field Research Challenge Site

    Kerkhof, L.; Williams, K.H.; Long, P.E.; McGuinness, L.

    2011-02-21

    Previous experiments at the Rifle, Colorado Integrated Field Research Challenge (IFRC) site demonstrated that field-scale addition of acetate to groundwater reduced the ambient soluble uranium concentration. In this report, sediment samples collected before and after acetate field addition were used to assess the active microbes via {sup 13}C acetate stable isotope probing on 3 phases [coarse sand, fines (8-approximately 150 {micro}m), groundwater (0.2-8 {micro}m)] over a 24-day time frame. TRFLP results generally indicated a stronger signal in {sup 13}C-DNA in the 'fines' fraction compared to the sand and groundwater. Before the field-scale acetate addition, a Geobacter-like group primarily synthesized {sup 13}C-DNA in the groundwater phase, an alpha Proteobacterium primarily grew on the fines/sands, and an Acinetobacter sp. and Decholoromonas-like OTU utilized much of the {sup 13}C acetate in both groundwater and particle-associated phases. At the termination of the field-scale acetate addition, the Geobacter-like species was active on the solid phases rather than the groundwater, while the other bacterial groups had very reduced newly synthesized DNA signal. These findings will help to delineate the acetate utilization patterns of bacteria in the field and can lead to improved methods for stimulating distinct microbial populations in situ.

  12. Decline in suspended sediment concentration delivered by the Changjiang (Yangtze) River into the East China Sea between 1956 and 2013

    Dai, Zhijun; Fagherazzi, Sergio; Mei, Xuefei; Gao, Jinjuan

    2016-09-01

    The temporal evolution of suspended sediment concentration (SSC) in a river debouching into the ocean provides vital insights into erosion processes in the watershed and dictates the evolution of the inner continental shelf. While the delivery of sediment from rivers to the ocean has received special attention in the recent past, few studies focused on the variability and dynamics of river SSC, especially in the Changjiang (Yangtze) river, China, the longest river in Asia. Here, variations in SSC delivered by the Changjiang River to the East China Sea and possible causes of its variability were detected based on a long-term time series of daily SSC and monthly water discharge measured at the Datong gauging station. The SSC data are further compared to a hydrological analysis of yearly precipitation covering the entire catchment. The results indicate the presence of a decline in SSC in the period 1956-2013, which can be divided into three phases: (i) high SSC (0.69 kg/m3) in the wet season and low SSC (0.2 kg/m3) in the dry season from 1956 to 1970; (ii) relative high SSC (0.58 kg/m3) in the wet season and low SSC (0.15 kg/m3) in the dry season from 1971 to 2002; and (iii) low SSC (0.19 kg/m3) in the wet season and very low SSC (0.09 kg/m3) in the dry season after 2002. These three periods have a mean yearly SSC values of 0.62, 0.42, and 0.18 kg/m3, respectively. Compared with 1956-1970, the slope of the rating curve between SSC and water discharge decreased, respectively, by 2% and 30% during the period 1971-2002 and 2002-2013. Soil erosion, dam construction, and banks reinforcement along the Changjiang River are the main causes of SSC variations. Fluctuations in water discharge are also controlling the SSC long-term variations. Specifically, from 1956 to 1970, the effect of soil erosion overrules that of dam impoundment, which is likely responsible for the high SSC; during the period 1970-2002, the influence of dam impoundment increases while that of soil erosion

  13. Comparison between heavy metal concentrations in sediments analysed by two methods: Analyses on detection limits and data quality

    Chemical components in geological samples are often measured by more than one method to be able to measure high concentrations in resistant minerals as well as low concentrations in other mineral phases. For quality control, it is necessary to evaluate if the results from these methods are consistent or not. A total of 1884 sediment samples taken from the Leinster area of Ireland were analysed by both instrumental neutron activation analysis (INAA) and atomic absorption spectrometry (AAS) for 5 chemical elements (Co, Cr, Fe, Ni, and Zn). It is well known that INAA detects the total concentrations of chemical elements, but it has much higher detection limits than AAS. In this study, descriptive statistics, scatter plots, statistical tests and GIS mapping techniques were employed to compare the differences between the results from the two analytical methods, and to evaluate the impact of detection limits on data quality. Descriptive statistics and scatter plots were effective in showing the discrepancies between values of the two methods. Scatter plots showed outliers and the poor accuracy of INAA for concentrations close to or below the detection limits. It is suggested that errors may have happened during both INAA and AAS processes for some samples. Statistical results of both nonparametric sign and Wilcoxon signed rank tests showed that the differences between concentrations measured with the two methods were significant at the level of p < 0.001, and the average differences were 20-30% for the 5 elements. Meanwhile, more than 25% of all samples showed differences greater than 40-60% for these elements. After removing values lower than 3 times detection limits of both methods, only a slight improvement was achieved for the consistency between the two methods. Besides detection limits, the incomplete digestion prior to AAS may have played an important role. The higher AAS values of Ni than its INAA values may have been caused by multiple detection limits in

  14. Assessments of radioactivity concentration of natural radionuclides and radiological hazard indices in sediment samples from the East coast of Tamilnadu, India with statistical approach.

    Ravisankar, R; Chandramohan, J; Chandrasekaran, A; Prince Prakash Jebakumar, J; Vijayalakshmi, I; Vijayagopal, P; Venkatraman, B

    2015-08-15

    This paper reports on the distribution of three natural radionuclides (238)U, (232)Th and (40)K in coastal sediments from Pattipulam to Devanampattinam along the East coast of Tamilnadu to establish baseline data for future environmental monitoring. Sediment samples were collected by a Peterson grab samples from 10m water depth parallel to the shore line. Concentration of natural radionuclides were determined using a NaI(Tl) detector based γ-spectrometry. The mean activity concentration is ⩽2.21, 14.29 and 360.23Bqkg(-1) for (238)U, (232)Th and (40)K, respectively. The average activity of (232)Th, (238)U and (40)K is lower when compared to the world average value. Radiological hazard parameters were estimated based on the activity concentrations of (238)U, (232)Th and (40)K to find out any radiation hazard associated with the sediments. The radiological hazard parameters such as radium equivalent activity (Raeq), absorbed gamma dose rates in air (DR), the annual gonadal dose equivalent (AGDE), annual effective dose equivalent (AEDE), external hazard index (Hex) internal hazard index (Hin), activity utilization index (AUI) and excess lifetime cancer (ELCR) associated with the radionuclides were calculated and compared with internationally approved values and the recommended safety limits. Pearson correlation, principal component analysis (PCA) and hierarchical cluster analysis (HCA) have been applied in order to recognize and classify radiological parameters in sediments collected at 22 sites on East coast of Tamilnadu. The values of radiation hazard parameters were comparable to the world averages and below the recommended values. Therefore, coastal sediments do not to pose any significant radiological health risk to the people living in nearby areas along East coast of Tamilnadu. The data obtained in this study will serve as a baseline data in natural radionuclide concentration in sediments along the coastal East coast of Tamilnadu. PMID:26036177

  15. Uranium hydrogeochemical and stream sediment reconnaissance of the Dalhart NTMS quadrangle, New Mexico/Texas/Oklahoma, including concentrations of forty-two additional elements

    Morgan, T.L.

    1980-08-01

    Totals of 1583 water samples and 503 sediment samples were collected from 2028 locations within the 20 000-km/sup 2/ area of the quadrangle at an average density of one location per 9.86 km/sup 2/. Water samples were collected from wells, springs, and streams and were analyzed for uranium. Sediment samples were collected from streams and springs and were analyzed for uranium, thorium, and 41 additional elements. All field and analytical data are listed in the appendixes of this report. Discussion is limited to anomalous samples, which are considered to be those containing over 20 ppB uranium for waters and over 5 ppM uranium for sediments. Uranium concentrations in water samples range from below the detection limit of 0.2 ppB to 1457.65 ppB and average 7.41 ppB. Most of the seventy anomalous water samples (4.4% of all water samples) are grouped spatially into five clusters or areas of interest. Samples in three of the clusters were collected along the north edge of the quadrangle where Mesozoic strata are exposed. The other two clusters are from the central and southern portions where the Quaternary Ogallala formation is exposed. Sediment samples from the quadrangle have uranium concentrations that range from 0.90 ppM to 27.20 ppM and average 3.27 ppM. Fourteen samples (2.8% of all sediment samples) contain over 5 ppM uranium and are considered anomalous. The five samples with the highest concentrations occur where downcutting streams expose Cretaceous units beneath the Quaternary surficial deposits. The remaining anomalous sediment samples were collected from scattered locations and do not indicate any single formation or unit as a potential source for the anomalous concentrations.

  16. Seasonal mercury concentrations and δ15N and δ13C values of benthic macroinvertebrates and sediments from a historically polluted estuary in south central Chile

    The Lenga Estuary is one of the most industrialized sites in south central Chile where the historic operation of chlor-alkali plants resulted in large quantities of mercury (Hg) being deposited into the estuary. This historical contamination may still represent a risk to the biota in the estuary. To investigate this four macroinvertebrates, Neotrypaea uncinata (ghostshrimp), Elminius kingii (barnacle), Hemigrapsus crenulatus (shore crab) and Perinereis gualpensis (ragworm) were collected seasonally from three different sites in the Lenga Estuary and one in a reference estuary (Tubul Estuary), and analyzed for Hg and stable isotopes (δ15N and δ13C). Mercury concentrations in Lenga sediments ranged from 0.4 ± 0.1 to 13 ± 3 mg/kg, while those in Tubul sediments ranged from 0.02 ± 0.01 to 0.07 ± 0.09 mg/kg. Total Hg concentrations of invertebrates were significantly different between estuaries (p 0.05). In contrast, organic Hg concentrations were different by species and season with shore crab muscle tissues exhibiting the greatest percent difference. Site-specific relationships demonstrated that total Hg concentrations in ragworm best reflected the total Hg sediment mercury concentrations. Signatures of δ13C were correlated to the organic Hg % rather than total Hg. This suggests that organic Hg concentrations in these species were related to the carbon sources. -- Highlights: ► Hg in sediments and biota from Lenga Estuary were elevated compared to nearby estuary. ► Invertebrates showed interspecific and seasonal differences in terms of organic Hg %. ► Total Hg levels in the ragworm best reflect Hg sediment gradient in Lenga Estuary. ► Interspecific variation in δ13C signatures indicated different feeding modes. ► Organic forms of Hg in invertebrates were mainly related to the carbon sources.

  17. Tryptophan hydroxylase gene 1 (TPH1) variants associated with cerebrospinal fluid 5-hydroxyindole acetic acid and homovanillic acid concentrations in healthy volunteers

    Andreou, Dimitrios; Saetre, Peter; Werge, Thomas; Andreassen, Ole A; Agartz, Ingrid; Sedvall, Göran C; Hall, Håkan; Terenius, Lars; Jönsson, Erik G

    Tryptophan hydroxylase (TPH) is the rate-limiting enzyme in serotonin synthesis. We investigated possible relationships between five TPH1 gene polymorphisms and cerebrospinal fluid (CSF) concentrations of the major serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA), the major dopamine...

  18. Responses in sediment phosphorus and lanthanum concentrations and composition across 10 lakes following applications of lanthanum modified bentonite

    Dithmer, Line; Nielsen, Ulla Gro; Lürling, Miquel;

    2016-01-01

    A combined field and laboratory scale study of 10 European lakes treated between 2006 and 2013 with a lanthanum (La) modified bentonite (LMB) to control sediment phosphorus (P) release was conducted. The study followed the responses in sediment characteristics including La and P fractions and...... were also reported, in the earliest treated lake. Molar ratios between La and P in the sediments were generally above 1, demonstrating excess La relative to P. Lanthanum was vertically mixed in the sediment down to a depth of 10 cm for eight of the ten lakes, and recovery of La in excess of 100% of the...

  19. Regional variability in bed-sediment concentrations of wastewater compounds, hormones and PAHs for portions of coastal New York and New Jersey impacted by hurricane Sandy

    Phillips, Patrick; Gibson, Cathy A; Fisher, Shawn C.; Fisher, Irene; Reilly, Timothy J.; Smalling, Kelly; Romanok, Kristin; Foreman, William; ReVello, Rhiannon C.; Focazio, Michael J.; Jones, Daniel K.

    2016-01-01

    Bed sediment samples from 79 coastal New York and New Jersey, USA sites were analyzed for 75 compounds including wastewater associated contaminants, PAHs, and other organic compounds to assess the post-Hurricane Sandy distribution of organic contaminants among six regions. These results provide the first assessment of wastewater compounds, hormones, and PAHs in bed sediment for this region. Concentrations of most wastewater contaminants and PAHs were highest in the most developed region (Upper Harbor/Newark Bay, UHNB) and reflected the wastewater inputs to this area. Although the lack of pre-Hurricane Sandy data for most of these compounds make it impossible to assess the effect of the storm on wastewater contaminant concentrations, PAH concentrations in the UHNB region reflect pre-Hurricane Sandy conditions in this region. Lower hormone concentrations than predicted by the total organic carbon relation occurred in UHNB samples, suggesting that hormones are being degraded in the UHNB region.

  20. Regional variability in bed-sediment concentrations of wastewater compounds, hormones and PAHs for portions of coastal New York and New Jersey impacted by hurricane Sandy.

    Phillips, Patrick J; Gibson, Catherine A; Fisher, Shawn C; Fisher, Irene J; Reilly, Timothy J; Smalling, Kelly L; Romanok, Kristin M; Foreman, William T; ReVello, Rhiannon C; Focazio, Michael J; Jones, Daniel K

    2016-06-30

    Bed sediment samples from 79 coastal New York and New Jersey, USA sites were analyzed for 75 compounds including wastewater associated contaminants, PAHs, and other organic compounds to assess the post-Hurricane Sandy distribution of organic contaminants among six regions. These results provide the first assessment of wastewater compounds, hormones, and PAHs in bed sediment for this region. Concentrations of most wastewater contaminants and PAHs were highest in the most developed region (Upper Harbor/Newark Bay, UHNB) and reflected the wastewater inputs to this area. Although the lack of pre-Hurricane Sandy data for most of these compounds make it impossible to assess the effect of the storm on wastewater contaminant concentrations, PAH concentrations in the UHNB region reflect pre-Hurricane Sandy conditions in this region. Lower hormone concentrations than predicted by the total organic carbon relation occurred in UHNB samples, suggesting that hormones are being degraded in the UHNB region. PMID:27177500

  1. COMPARISON AMONG ORGANIC MATTER, NUTRIENTS AND HEAVY METALS CONCENTRATIONS IN SEDIMENTS OF TWO LOTIC AQUATIC SYSTEMS, RIBEIRA DO IGUAPE WATERSHED, SP, BRAZIL

    Maria do Carmo Calijuri

    2008-08-01

    Full Text Available Developed in Ribeira do Iguape Watershed, one of the poorest regions in São Paulo state, Southeast Brazil, this research aimed to characterize the sediment of Jacupiranguinha and Pariquera-Açu Rivers. Eight sampling stations were demarcated on each river, covering strategic places. In all samples, organic matter content, total phosphorus and nitrogen, cadmium, lead, copper, manganese and mercury concentrations were determined. The results showed that the sediment of both rivers could be considered mineral, since the organic matter contents were all lower than 10%. There was evident increment on total phosphorus and nitrogen concentrations after the discharge of a fertilizers’ factory effluent, in Jacupiranguinha River, and after the effluent of a stabilization pound in Pariquera-Açu River. The highest copper, manganese and mercury concentrations were detected in Jacupiranguinha River sediment: 22.0 mg kg-1, 551.0 mg kg-1 e 0.15 mg kg-1 (Sampling Station 6, which corresponds to the discharge of the industrial effluent. The highest lead concentration was found in Pariquera-Açu River, 26.0 mg kg-1, in Sampling Station 8. Igeo (Geoaccumulation Index calculus revealed that the sediments of both rivers were not polluted by the metals that were quantified.

  2. Carbon isotopes and iodine concentrations in a Mississippi River delta core recording land use, sediment transport, and dam building in the river?s drainage basin

    Santschi, Peter H.; Oktay, Sarah D.; Cifuentes, Luis

    2007-01-01

    Carbon isotopes and iodine concentrations in a Mississippi River delta core recording land use, sediment transport, and dam building in the river?s drainage basin correspondence: Corresponding author. (Santschi, Peter H.) (Santschi, Peter H.) Laboratory for Oceanographic and Environmental Research (LOER), Dept. of Marine Sciences and Oceanography, Texas A&M University at Galveston - 5007 Ave U--> , Galveston--> ...

  3. Mercury concentration in the sediments as a function of changing climate in coastal zone of Southern Baltic Sea – preliminary results

    Bełdowska M.

    2013-04-01

    Full Text Available Mercury, despite of its many uses in industry, is also highly toxic. It is highly neurotoxic, and because of the ability of mercury to penetrate placental barrier, in some countries ban on predatory fish consumption (the main route of mercury into human organism by pregnant women was introduced. There are very little publications describing the consequences of weather anomalies on contaminants cycles. No research was published concerning the reemission of Hg due to climate change in the Southern Baltic Sea. The study area was situated in the coastal zone of the Gulf of Gdansk - the Southern Baltic. Samples of different species of macrophytobenthos were collected once a month during 2006-2012. Samples of Potamogeton pectinatus, sediments and pore waters were collected once a month from February 2011 to January 2012. The climate changes in the moderate latitudes: extension of the fall season, has contributed to stabilization of high concentrations of mercury in pore waters. Lack of ice cover in the coastal zone and simultaneous occurrence of storms had an impact on supply of the organic matter to the sediments and the increased concentration of Hg. More intense burning of fossil fuels in this season favored the increased metal concentration in the atmosphere and consequently an increase of the atmospheric deposition of metals to the sediments. This led to a fourfold increase of the mercury concentration in sediments as compared to fall season.

  4. Sediment-associated aliphatic and aromatic hydrocarbons in coastal British Columbia, Canada: Concentrations, composition, and associated risks to protected sea otters

    Sediment-associated hydrocarbons can pose a risk to wildlife that rely on benthic marine food webs. We measured hydrocarbons in sediments from the habitat of protected sea otters in coastal British Columbia, Canada. Alkane concentrations were dominated by higher odd-chain n-alkanes at all sites, indicating terrestrial plant inputs. While remote sites were dominated by petrogenic polycyclic aromatic hydrocarbons (PAHs), small harbour sites within sea otter habitat and sites from an urban reference area reflected weathered petroleum and biomass and fossil fuel combustion. The partitioning of hydrocarbons between sediments and adjacent food webs provides an important exposure route for sea otters, as they consume ∼25% of their body weight per day in benthic invertebrates. Thus, exceedences of PAH sediment quality guidelines designed to protect aquatic biota at 20% of the sites in sea otter habitat suggest that sea otters are vulnerable to hydrocarbon contamination even in the absence of catastrophic oil spills. - Highlights: → Sediment hydrocarbon signatures differed between remote and impacted coastal sites. → A natural background comprised terrestrial plant alkanes and petrogenic PAHs. → Impacted sites reflected a history of petrogenic and pyrogenic hydrocarbon inputs. → Hydrocarbons at some sites exceeded guidelines for the protection of aquatic life. → Protected sea otters may thus be at risk as they rely primarily on benthic prey. - Anthropogenically-derived hydrocarbons in coastal sediments in British Columbia may pose a risk to protected sea otters.

  5. Sediment-associated aliphatic and aromatic hydrocarbons in coastal British Columbia, Canada: Concentrations, composition, and associated risks to protected sea otters

    Harris, Kate A. [Fisheries and Oceans Canada, Institute of Ocean Sciences, P.O. Box 6000, Sidney BC V8L 4B2 (Canada); University of Victoria, School of Earth and Ocean Sciences, P.O. Box 1700 STN CSC, Victoria BC V8W 2Y2 (Canada); Yunker, Mark B. [7137 Wallace Dr., Brentwood Bay, BC V8M 1G9 (Canada); Dangerfield, Neil [Fisheries and Oceans Canada, Institute of Ocean Sciences, P.O. Box 6000, Sidney BC V8L 4B2 (Canada); Ross, Peter S., E-mail: Peter.S.Ross@dfo-mpo.gc.ca [Fisheries and Oceans Canada, Institute of Ocean Sciences, P.O. Box 6000, Sidney BC V8L 4B2 (Canada)

    2011-10-15

    Sediment-associated hydrocarbons can pose a risk to wildlife that rely on benthic marine food webs. We measured hydrocarbons in sediments from the habitat of protected sea otters in coastal British Columbia, Canada. Alkane concentrations were dominated by higher odd-chain n-alkanes at all sites, indicating terrestrial plant inputs. While remote sites were dominated by petrogenic polycyclic aromatic hydrocarbons (PAHs), small harbour sites within sea otter habitat and sites from an urban reference area reflected weathered petroleum and biomass and fossil fuel combustion. The partitioning of hydrocarbons between sediments and adjacent food webs provides an important exposure route for sea otters, as they consume {approx}25% of their body weight per day in benthic invertebrates. Thus, exceedences of PAH sediment quality guidelines designed to protect aquatic biota at 20% of the sites in sea otter habitat suggest that sea otters are vulnerable to hydrocarbon contamination even in the absence of catastrophic oil spills. - Highlights: > Sediment hydrocarbon signatures differed between remote and impacted coastal sites. > A natural background comprised terrestrial plant alkanes and petrogenic PAHs. > Impacted sites reflected a history of petrogenic and pyrogenic hydrocarbon inputs. > Hydrocarbons at some sites exceeded guidelines for the protection of aquatic life. > Protected sea otters may thus be at risk as they rely primarily on benthic prey. - Anthropogenically-derived hydrocarbons in coastal sediments in British Columbia may pose a risk to protected sea otters.

  6. Concentrations and transport of suspended sediment, nutrients, and pesticides in the lower Mississippi-Atchafalaya River subbasin during the 2011 Mississippi River flood, April through July

    Welch, Heather L.; Coupe, Richard H.; Aulenbach, Brent T.

    2014-01-01

    High streamflow associated with the April–July 2011 Mississippi River flood forced the simultaneous opening of the three major flood-control structures in the lower Mississippi-Atchafalaya River subbasin for the first time in history in order to manage the amount of water moving through the system. The U.S. Geological Survey (USGS) collected samples for analysis of field properties, suspended-sediment concentration, particle-size, total nitrogen, nitrate plus nitrite, total phosphorus, orthophosphate, and up to 136 pesticides at 11 water-quality stations and 2 flood-control structures in the lower Mississippi-Atchafalaya River subbasin from just above the confluence of the upper Mississippi and Ohio Rivers downstream from April through July 2011. Monthly fluxes of suspended sediment, suspended sand, total nitrogen, nitrate plus nitrite, total phosphorus, orthophosphate, atrazine, simazine, metolachlor, and acetochlor were estimated at 9 stations and 2 flood-control structures during the flood period. Although concentrations during the 2011 flood were within the range of what has been observed historically, concentrations decreased during peak streamflow on the lower Mississippi River. Prior to the 2011 flood, high concentrations of suspended sediment and nitrate were observed in March 2011 at stations downstream of the confluence of the upper Mississippi and Ohio Rivers, which probably resulted in a loss of available material for movement during the flood. In addition, the major contributor of streamflow to the lower Mississippi-Atchafalaya River subbasin during April and May was the Ohio River, whose water contained lower concentrations of suspended sediment, pesticides, and nutrients than water from the upper Mississippi River. Estimated fluxes for the 4-month flood period were still quite high and contributed approximately 50 percent of the estimated annual suspended sediment, nitrate, and total phosphorus fluxes in 2011; the largest fluxes were estimated at

  7. A Semi-Analytical Model for Remote Sensing Retrieval of Suspended Sediment Concentration in the Gulf of Bohai, China

    Jin-Ling Kong

    2015-04-01

    Full Text Available Suspended sediment concentration (SSC is one of the most critical parameters in ocean ecological environment evaluation and it can be determined using ocean color remote sensing (RS. The purpose of this study is to develop a model that provides a reliable and sensitive evaluation of SSC retrieval using RS data. Data were acquired for and gathered from the Gulf of Bohai where SSC levels are relatively low with an average value below 30 mg·L−1. The study indicates that the most sensitive band to SSC levels in the study area is the NIR band of Landsat5 TM images. A quadratic polynomial semi-analytical model appears to be the best retrieval model based on the relationship between the inherent optical properties (IOPs and apparent optical properties (AOPs of water as described by the quasi-analytical algorithm (QAA. The model has a higher precision and effectiveness for SSC retrieval than data-driven statistical models, especially when SSC level is relatively high. The average relative error and the root mean square error (RMSE are 12.32% and 4.53 mg·L−1, respectively, while the correlation coefficient between observed and estimated SSC by the model is 0.95. Using the proposed retrieval model and TM data, SSC levels of the entire study region in the Gulf of Bohai were estimated. These estimates can serve as the baseline for efficient monitoring of the ocean environment in the future.

  8. In situ Raman-based measurements of high dissolved methane concentrations in hydrate-rich ocean sediments

    Zhang, Xin; Hester, Keith C.; Ussler, William; Walz, Peter M.; Peltzer, Edward T.; Brewer, Peter G.

    2011-04-01

    Ocean sediment dissolved CH4 concentrations are of interest for possible climate-driven venting from sea floor hydrate decomposition, for supporting the large-scale microbial anaerobic oxidation of CH4 that holds the oceanic CH4 budget in balance, and for environmental issues of the oil and gas industry. Analyses of CH4 from recovered cores near vent locations typically show a maximum of ˜1 mM, close to the 1 atmosphere equilibrium value. We show from novel in situ measurement with a Raman-based probe that geochemically coherent profiles of dissolved CH4 occur rising to 30 mM (pCH4 = 3 MPa) or an excess pressure ˜3× greater than CO2 in a bottle of champagne. Normalization of the CH4 Raman ν1 peak to the ubiquitous water ν2 bending peak provides a fundamental internal calibration. Very large losses of CH4 and fractions of other gases (CO2, H2S) must typically occur from recovered cores at gas rich sites. The new data are consistent with observations of microbial biomass and observed CH4 oxidation rates at hydrate rich sites and support estimates of a greatly expanded near surface oceanic pore water CH4 reservoir.

  9. Remotely sensed variability of the suspended sediment concentration and its response to decreased river discharge in the Yangtze estuary and adjacent coast

    Shen, Fang; Zhou, Yunxuan; Li, Jiufa; He, Qing; Verhoef, Wouter

    2013-10-01

    Satellite observation is an excellent tool for exploring the variability of the suspended sediment concentration (SSC) of turbid estuarine and coastal waters. We used a recently developed semi-empirical radiative transfer model combined with a multi-wavelength switching algorithm for the SSC retrieval from MEdium Resolution Imaging Spectrometer (MERIS) satellite data. This method can successfully retrieve SSC from satellite data in turbid estuarine and coastal waters with a wide range of sediment concentrations (20-2500 mg l-1) and is robust for quantifying realistic patterns of the surface sediment dynamics. The seasonal and annual variability of the MERIS-derived SSC from 2003 to 2010 were analysed in this work. Five regions-of-interest (ROIs) in the Yangtze estuary and coast are included in the analysis: the upper estuary, the lower estuary, the outer estuary, the Hangzhou Bay and the Qidong shore. The results reveal that the SSC of the upper estuary has significant seasonal and annual variations in response to seasonal cycling and annual fluctuation of the river discharge. A long-term continuing decrease of river discharge may cause an overall decline of the SSC in the entire estuary and adjacent areas. The existence of horizontal exchanges of the sediments between the Yangtze estuary and the Jiangsu coast implies that the decreased fluvial sediment loads of the estuary may partially be compensated by supplementing contributions from other origins.

  10. Concentrations of metals in water, sediment, biofilm, benthic macroinvertebrates, and fish in the boulder river watershed, Montana, and the role of colloids in metal uptake

    Farag, A.M.; Nimick, D.A.; Kimball, B.A.; Church, S.E.; Harper, D.D.; Brumbaugh, W.G.

    2007-01-01

    To characterize the partitioning of metals in a stream ecosystem, concentrations of trace metals including As, Cd, Cu, Pb, and Zn were measured in water, colloids, sediment, biofilm (also referred to as aufwuchs), macroinvertebrates, and fish collected from the Boulder River watershed, Montana. Median concentrations of Cd, Cu, and Zn in water throughout the watershed exceeded the U.S. EPA acute and chronic criteria for protection of aquatic life. Concentrations of As, Cd, Cu, Pb, and Zn in sediment were sufficient in the tributaries to cause invertebrate toxicity. The concentrations of As, Cu, Cd, Pb, and Zn in invertebrates from lower Cataract Creek (63, 339, 59, 34, and 2,410 ??g/g dry wt, respectively) were greater than the concentrations in invertebrates from the Clark Fork River watershed, Montana (19, 174, 2.3, 15, and 648 ??g/g, respectively), that were associated with reduced survival, growth, and health of cutthroat trout fed diets composed of those invertebrates. Colloids and biofilm seem to play a critical role in the pathway of metals into the food chain and concentrations of As, Cu, Pb, and Zn in these two components are significantly correlated. We suggest that transfer of metals associated with Fe colloids to biological components of biofilm is an important pathway where metals associated with abiotic components are first available to biotic components. The significant correlations suggest that Cd, Cu, and Zn may move independently to biota (biofilm, invertebrates, or fish tissues) from water and sediment. The possibility exists that Cd, Cu, and Zn concentrations increase in fish tissues as a result of direct contact with water and sediment and indirect exposure through the food chain. However, uptake through the food chain to fish may be more important for As. Although As concentrations in colloids and biofilm were significantly correlated with As water concentrations, As concentrations in fish tissues were not correlated with water. The pathway for

  11. Relationships between Heavy Metal Concentrations in the American Oyster (Crassostrea virginica and Metal Levels in the Water Column and Sediment in Apalachicola Bay, Florida

    Dennis A. Apeti

    2005-01-01

    Full Text Available This study aims to assess baseline concentrations of heavy metals (Cd, Cr, Cu, Pb and Zn in the oyster soft tissue as they relate to concentrations in the water column (particulate phase and sediment in Apalachicola Bay. In order to conduct these assessments, a total of 360 samples, collected in two seasons (winter and summer and were analyzed using atomic absorption spectrometry. Results indicated that elemental concentrations in particulate phase correlate significantly with concentration in the tissue than those in the sediment. Moreover, assessment of seasonal and spatial variations have indicated that oysters collected in the winter have significantly higher (P<0.05 Cu, Pb and Zn concentrations than oysters collected in the summer. However, metal concentrations in sediment did not show such patterns. These observations confirmed the fact that metals in the particulate phase are more bioavailable to oysters and that the oysters can be used as good indicators of the spatial and temporal variation of the heavy metals in the aquatic system.

  12. Surprising abundance of Gallionella-related iron oxidizers in creek sediments at pH 4.4 or at high heavy metal concentrations

    Maria eFabisch

    2013-12-01

    Full Text Available We identified and quantified abundant iron-oxidizing bacteria (FeOB at three iron-rich, metal-contaminated creek sites with increasing sediment pH from extremely acidic (R1, pH 2.7, to moderately acidic (R2, pH 4.4, to slightly acidic (R3, pH 6.3 in a former uranium-mining district. The geochemical parameters showed little variations over the 1.5 year study period. The highest metal concentrations found in creek sediments always coincided with the lowest metal concentrations in creek water at the slightly acidic site R3. Sequential extractions of R3 sediment revealed large portions of heavy metals (Ni, Cu, Zn, Pb, U bound to the iron oxide fraction. Light microscopy of glass slides exposed in creeks detected twisted stalks characteristic of microaerobic FeOB of the family Gallionellaceae at R3 but also at the acidic site R2. Sequences related to FeOB such as Gallionella ferruginea, Sideroxydans sp. CL21, Ferritrophicum radicicola, and Acidovorax sp. BrG1 were identified in the sediments. The highest fraction of clone sequences similar to the acidophilic ‘Ferrovum myxofaciens’ was detected in R1. Quantitative PCR using primer sets specific for Gallionella spp., Sideroxydans spp., and ‘Ferrovum myxofaciens’ revealed that approximately 72% (R2 sediment and 37% (R3 sediment of total bacterial 16S rRNA gene copies could be assigned to groups of FeOB with dominance of microaerobic Gallionella spp. at both sites. Gallionella spp. had similar and very high absolute and relative gene copy numbers in both sediment communities. Thus, Gallionella-like organisms appear to exhibit a greater acid and metal tolerance than shown before. Microaerobic FeOB from R3 creek sediment enriched in newly developed metal gradient tubes tolerated metal concentrations of 35 mM Co, 24 mM Ni, and 1.3 mM Cd, higher than those in sediments. Our results will extend the limited knowledge of FeOB at contaminated, moderately to slightly acidic environments.

  13. Analysis of bio-obtainable endocrine disrupting metals in river water and sediment, sewage influent/effluent, sludge, leachate, and concentrated leachate, in the irish midlands shannon catchment.

    Reid, Antoinette M

    2009-01-01

    The application of an acid digestion and subsequent solid-phase extraction (SPE) procedure were implemented as preliminary treatments prior to quantifying the levels of potentially endocrine disrupting metals (EDMs) in a variety of solid and liquid matrices. These included (solid) river sediment, leachate sediment and sewage sludge and also (liquid) river water, landfill leachate, concentrated leachate, sewage influent, and sewage effluent, sampled in the Irish Midlands. The total concentrations of cobalt (Co), cadmium (Cd), copper (Cu), chromium (Cr), nickel (Ni), lead (Pb), zinc (Zn), and manganese (Mn), after extraction and preconcentration, were determined by atomic absorption spectroscopy (AAS). Mercury (Hg) in sediment and sludge was determined using cold-vapour atomic fluorescence spectroscopy (AFS). For sewage sludge maximum values (mg\\/kg(dw)) of 4700 Ni, 1642 Mn, 100.0 Cd, 3400 Zn, 36.70 Co, 750.0 Pb, 485.8 Cr, and 1003 Cu were determined whilst in leachate sediment, maximum values (mg\\/kg(dw)) of 32.10 Ni, 815.0 Mn, 32.78 Cd, 230.3 Zn, 26.73 Co, 3525 Pb, 124.9 Cr, and 50.13 Cu were found. Over several months, the data showed elevated levels in sewage influents, effluents, and sludges compared to a battery of adjacent river water samples and corresponding sediments. There was a definite trend for target values for sediments to be exceeded, while intervention values were only exceeded for cadmium. Overall the pattern in terms of concentration was sewage > leachate > river matrices. A nonparametric assessment of the effect of sewage treatment method on median metal levels in sludge revealed statistically significant differences at the 95% level of confidence for Co, Cr, and Hg and at the 90% level of confidence for Cd.

  14. Influence of the sea rush Juncus maritimus on metal concentration and speciation in estuarine sediment colonized by the plant.

    Almeida, C Marisa R; Mucha, Ana P; Vasconcelos, M Teresa S D

    2004-06-01

    Metal accumulation by Juncus maritimus and the role of this plant on the physical and chemical composition of sediments, from the Douro river estuary (NW Portugal), were investigated. The contents of Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn were determined (by atomic absorption spectrophotometry) in sediments, rhizosediments (those among plant roots and rhizomes), and different plant tissues (roots, rhizomes, leaves, and stems). Metal fractionation in sediments through sequential extraction was carried out and used for interpretation of sediment/J. maritimus interactions. Two estuarine sites with different characteristics were studied: site I displayed sandy sediment with lower organic matter and metals more weakly bound to it than site II sediment, which was muddy. At both sites, higher metal contents were observed in rhizosediments than in the surrounding sediment, but metals were more weakly bound to rhizosediment. Therefore, J. maritimus markedly influenced the sediments among its roots and rhizomes, changing metal distribution and speciation. Different patterns of both metal uptake and metal distribution among J. maritimus tissues were observed at the two sites. Plant bioaccumulation was only observed for Cd, Cu, and Zn, being similar for Cd atthe two sites and significantly higher for Cu and Zn (9 and 4 times higher, respectively) at site I. In conclusion, J. maritimus was shown to have potential for phytoextraction (or phytostabilization) of Cd, Cu, and Zn in estuarine environment. However, an eventual application of J. maritimus for this purpose will require a periodic removal of the plants together with their own rhizosediment. PMID:15224743

  15. Concentration and speciation of plutonium, americium, uranium, thorium, potassium and 137Cs in a venice canal sediment sample

    Testa, C.; Desideri, D.; Guerra, F.; Meli, M. A.; Roselli, C.; Degetto, S.

    1999-01-01

    A sequential extraction method consisting of six operationally-defined fractions has been developed for determining the geochemical partitioning of natural (U, Th, 40K) and antropogenic (Pu, Am, 137Cs) radionuclides in a 40-50 cm deep sediment sample collected in a Venice canal. Extraction chromatography with Microthene-TOPO (U, Th), Microthene-TNOA (Pu) and Microthene-HDEHP (Am) column was used for the chemical separation of a single radionuclide; the final recoveries were calculated by adding 236U, 229Th, 242Pu and 243Am as the yield tracers. After electrodeposition the alpha spectrometry was carried out. 137Cs and 40K were measured by gamma spectrometry. The total concentrations in the wet sample (Bq/kgd), obtained by a complete disgregation of the matrix by wet and dry treatment, were the following: 239+240Pu=1.03±0.07, 238Pu=0.022±0.005, 241Am=0.337±0.027, 137Cs=9.78±0.78, 238U=28.84±1.62, 232Th=21.42±1.93, 40K=376.05±12.78. The mean ratio 238Pu/239+240Pu (0.02) shows a contamination due essentially to fall-out and U and Th alpha spectra indicate the natural origin of two elements. The absence of 134Cs in the sample proves that at 40-50 cm depth the sediment was not affected by the Chernobyl fall-out. As far as the speciation is concerned the following fractions were considered: water soluble, carbonates, Fe-Mn oxides, organic matter, acid soluble, residue. Pu (˜67%) an Am (˜95%) were present principally in the carbonate fraction; U was more distributed and about 30% and 45% appeared in the carbonate fraction and in the residue respectively; the majority of Th was present in the residue (˜60%); 40K was totally present in the residue; finally 137Cs was found mostly in the acid soluble fraction (˜53%) and in the residue (˜47%). Some stable elements (Fe, Mn, Al, Ti, Ca, Pb, Ba) were also determined in the different fractions to get more information about the chemical association of the single radionuclides.

  16. Characteristics of sediment concentration variations in offshore area south of the Oujiang Estuary%瓯江南口外浅滩含沙浓度特征

    余蝶双; 李瑞杰; 丰青; 孔丛颖

    2013-01-01

    Based on the measured data of sediment in offshore area south of the Oujiang Estuary in Oct.2010,temporal and spatial variations of the sediment concentration were studied.A new sediment concentration formula was fitted by nonlinear least square method.Compared with the simple format of the Jiaju Liu formula ignoring the effect of wave,the applicability of the new formula was discussed.The results show that (1) sediment concentration decreases gradually from the south mouth of the Oujiang river to open sea.It is different during spring tide,middle tide and neap tide along the coastline; (2) sediment concentration increases gradually from surface to bottom in the vertical direction; (3) sediment concentration in spring tide is the highest,and higher in middle tide,and low in neap tide.It is higher in flood tide than that in ebb tide; (4) compared with the simple format of the Jiaju Liu formula ignoring the effect of wave,the fitting result of the new formula is highly related to the measured data of sediment concentration,and the relative error is small.%基于2010年10月瓯江南口外浅滩的泥沙实测资料,对含沙浓度的时空变化进行了分析研究.利用非线性最小二乘法拟合出了新的含沙量公式,并与刘家驹公式在不考虑波浪作用下的简式作比较,对新公式的适用性进行了探讨.分析结果表明:(1)含沙浓度从瓯江南口门向外海逐渐减小,沿岸方向的变化则存在大、中、小潮差异;(2)垂向上,含沙浓度由表层向底层逐渐增大;(3)含沙浓度具有大潮最大、中潮次之、小潮最小的特点,涨潮含沙浓度基本大于落潮含沙浓度;(4)与刘家驹公式相比,新公式的拟合结果与实测含沙量的相对误差较小,相关性较高.

  17. Benthic community structure in the Gorgan Bay (Southeast of the Caspian Sea, Iran: Correlation to water physiochemical factors and heavy metal concentration of sediment

    Mahmood Saghali

    2013-11-01

    Full Text Available Macrobentos frequency and biomass was investigated in the Gorgan Bay in 2011. Five sampling sites were chosen to collect benthos and sediment from the Bay using a Van Veen grab sampler. Samples were collected seasonally. Macrobenthos were indentified and their biomass was recorded. Sediment heavy metals concentration were measured using Atomic Absorption Spectroscopy. A total of 11 families belonging to three phyla of invertebrates were found. The phyla were Annelids (Nereidae, Naididae, Ampharetidae, Lumbriculidae, Tubificidae and Amphiporidae, Arthropods (Pontogammaridae, Balanidae and Chironomidae and Mollusks (Cardiidae and Scrobicularidae. Lumbriculidae (413 individuals m-2, corresponding to 18.7% and Cardiidae (55.2 g m-2, corresponding to 82.4% had the highest frequency and biomass, respectively. Annelids with an average of 1557 individuals m-2 was the most frequent groups, while, mollusks with the average of 141 g per m2 had the highest biomass. Results showed that macrobenthos frequency in summer was significantly higher than those of the other seasons, however, in the case of biomass, there was a significantly higher biomass in the spring than the other seasons. The maximum metal concentration was related to Zn and Pb, whereas, Cr and Cd had the lowest values. There was no significant difference in Zn and Cr concentrations among the sampling seasons. Pb concentration in winter was significantly lower than the other seasons, whereas, Cd concentrations in the spring and summer were significantly lower than the autumn and winter. There were some correlations between benthos frequency and water physiochemical characteristics and sediment heavy metal levels. This study indicated that benthic fauna of the Gorgan Bay and the Caspian Sea are not similar. Also, results showed that benthic fauna communities are affected by sediment heavy metal concentrations and water physiochemical characteristics, however, different benthos groups show

  18. Variations in selected water quality variables and metal concentrations in the sediment of the lower Olifants and Selati rivers, South Africa

    T. Seymore; H. H. du Preez; J.H.J. van Vuren; Deacon, A; Strydom, G

    1994-01-01

    A survey of the water and sediment quality of the lower Olifants River and lower Selati River was carried out. Metal concentrations (Cr, Cu, Fe, Mn, Ni, Pb, Sr and Zn) in the water and sediment, as well as the physical and chemical characteristics of the water were determined over a two-year period (April 1990 - February 1992). The water quality of the lower Selati River, which flows through the Phalaborwa area, was found to be influenced by the mining and industrial activities in the area. I...

  19. Fourier transform infrared spectroscopy, a new method for rapid determination of total organic and inorganic carbon and biogenic silica concentration in lake sediments

    Rosén, Peter; Vogel, Hendrik; Cunningham, Laura;

    2010-01-01

    We demonstrate the use of Fourier transform infrared spectroscopy (FTIRS) to make quantitative measures of total organic carbon (TOC), total inorganic carbon (TIC) and biogenic silica (BSi) concentrations in sediment. FTIRS is a fast and cost-effective technique and only small sediment samples are...... varied between r = 0.84-0.99 for TOC, r = 0.85-0.99 for TIC, and r = 0.68-0.94 for BSi. Because FTIR spectra contain information on a large number of both inorganic and organic components, there is great potential for FTIRS to become an important tool in paleolimnology....

  20. Investigating how fundamental parameters of XRF sample preparation and analysis affect the observed elemental concentration: an experiment using fluvial sediment from Sabah, Borneo.

    Higton, Sam; Walsh, Rory

    2015-04-01

    X-Ray Fluorescence (XRF) is an important technique for measuring the concentrations of geochemical elements and inorganic contaminants adsorbed to sediments as an input to sediment tracing methods used to evaluate sediment transport dynamics in river catchments. In addition to traditional laboratory-based XRF instruments, the advent of increasingly advanced portable handheld XRF devices now mean that samples of fluvial sediment can be analysed in the field or in the laboratory following appropriate sample preparation procedures. There are limitations and sources of error associated with XRF sample preparation and analysis, however. It is therefore important to understand how fundamental parameters involved in sample preparation and analysis, such as sample compression and measurement exposure duration, affect observed variability in measurement results. Such considerations become important if the resulting measurement variability is high relative to the natural variability in element concentrations at a sample site. This paper deployed a simple experimental design to assess the impacts of varying a number of sample preparation and XRF analysis parameters on recorded measurements of elemental concentrations of the fine fraction (machine versus a handheld Niton XL3t-900 XRF elemental analyser. Helium purging was used on both machines to enable measurement of lighter geochemical elements. Sediment sub-samples were taken from a larger homogenised sample from a sediment core taken from an in-channel lateral bench deposit of the Brantian river in Sabah, Borneo; the core site is being used for research into multi-proxy sediment fingerprinting as part of the Stability of Altered Forest Ecosystems (SAFE) project. Some fundamental sample preparation procedures consistent with US EPA Method 6200 were applied to all sediment samples in order to explore key variables of interest. All sediment samples were air-dried to constant weight and sample quantity was sufficient to

  1. Acetic acid extraction from aqueous solutions using fatty acids

    IJmker, H.M.; Gramblicka, M.; Kersten, S.R.A.; Ham, van der A.G.J.; Schuur, B.

    2014-01-01

    A major challenge for production of acetic acid via bio-based routes is cost-effective concentration and purification of the acetic acid from the aqueous solutions, for which liquid–liquid extraction is a possible method. A main challenge in extraction of acetic acid from dilute aqueous solutions is

  2. Fermentation characteristics of Fusarium oxysporum grown on acetate

    Panagiotou, Gianni; Pachidou, Fotini; Petroutsos, Dimitris;

    2008-01-01

    In this study, the growth characteristics of Fusarium oxysporum were evaluated in minimal medium using acetate or different mixtures of acetate and glucose as carbon source. The minimum inhibitory concentration (MIC) of acetic acid that F oxysporum cells could tolerate was 0.8% w/v while glucose...

  3. Concentrations and compositions of organochlorine contaminants in sediments, soils, crustaceans, fishes and birds collected from Lake Tai, Hangzhou Bay and Shanghai city region, China

    Contamination by persistent organochlorines (OCs), such as DDTs, hexachlorocyclohexane isomers (HCHs), chlordane compounds (CHLs), hexachlorobenzene (HCB) and polychlorinated biphenyls (PCBs) were examined in sediments, soils, fishes, crustaceans, birds, and aquaculture feed from Lake Tai, Hangzhou Bay, and in the vicinity of Shanghai city in China during 2000 and 2001. OCs were detected in all samples analyzed, and DDT and its metabolites were the predominant contaminants in most sediments, soils and biota. Concentrations of p,p'-DDT and ratio of p,p'-DDT to ΣDDTs were significantly higher in marine fishes than those in freshwater fishes. While the use of DDTs has been officially banned in China since 1983, these results indicate a recent input of technical DDTs into the marine environment around Hangzhou Bay. Comparison of organochlorine concentrations in fishes collected from Lake Tai and Hangzhou Bay suggests the presence of local sources of HCHs, chlordanes and PCBs at Lake Tai. Higher proportions of penta- and hexa-PCB congeners in fishes at Lake Tai may suggest the use of highly chlorinated PCB product, such as PCB5, around this lake. To our knowledge, this is a first comprehensive study to examine the present status of organochlorine contamination in various environmental media, such as sediments, soils and wildlife, in China. - Elevated concentrations of DDTs were detected in sediments, soils, and wildlife collected from China

  4. Equilibrium Sampling of Persistent and Bioaccumulative Compounds in Soil and Sediment: Comparison of Two Approaches To Determine Equilibrium Partitioning Concentrations in Lipids

    Mäenpää, Kimmo; Leppänen, Matti T.; Reichenberg, Fredrik; Figueiredo, Kaisa; Mayer, Philipp

    2011-01-01

    The equilibrium sampling in silicone is increasingly applied to measure freely dissolved concentrations and chemical activities within bioaccumulation research of hydrophobic organic chemicals. Two equilibrium methods were applied to PCBcontaminated soil and sediment, and directly calibrated with...... respect to equilibrium partitioning concentrations in lipids (Clipid,partitioning): (i) Solid phase microextraction in the headspace above the sample (HS-SPME) required optimization for its application to PCBs, and it was calibrated above external partitioning standards in olive oil. (ii) Equilibrium...... results of the two methods were in good agreement and thus validated each other. Finally, the coated glass jar method was applied to field sediment containing invertebrates, which lead to Clipid,partitioning thatwereabouttwotimes higher thanmeasuredlipidnormalized concentrations in the organisms...

  5. Nitrification Potential of Mud Sediment of the Ariake Sea Tidal Flat and the Individual Effect of Temperature, pH, Salinity and Ammonium Concentration on its Nitrification Rate

    Alim Isnansetyo

    2011-08-01

    Full Text Available The aims of this study were to know the nitrification potential of the mud sediment of the Ariake sea tidal flat, and to investigate the individual influence of environmental parameters such as temperature, pH, salinity and ammonium concentration on its nitrification rate. The Ariake Sea is a semi-closed shallow sea with macro-tidal and the largest tidal flat in Japan. Nitrification Potential Rate (NPR and Nitrification Rate (NR of the tidal flat mud sediment were determined by amending sodium chlorate to inhibit the oxidation of NO2-N to NO3-N. NPRs of the sediment were 91.4, 71.2 and 64.8 nmol N/g Dry Weight Sediment (DWS/h at the depth of 0-3, 3-6 and 6-9 cm, respectively. NRs were relatively high in the temperatures range of 20-35oC with the optimum temperature of 29.3oC. Relatively high NRs were determined in the range of pHs 7.5-8 with the optimum pH 7.7. The optimum salinity for nitrification was 15 ppt. NRs increased drastically in the range of salinity 10 to 15 ppt, but it decreased sharply at 15 to 20 ppt. Relationship between ammonium concentration and NR resulted a hyperbolic Michaëlis-Menten type curve (R2 = 0.98 with the maximum NR rate (Vmax 32.5 nmol N/g DWS/h at NH4-N concentration 3,000 mM and the half saturation constant (Ks 700 mM NH4-N. To our knowledge, this is the first report on nitrification of mud sediment of the Ariake sea tidal flat, and its optimal temperature, pH, salinity and NH4-N concentration as a single parameter.

  6. Effects of wind farm construction on concentrations and fluxes of dissolved organic carbon and suspended sediment from peat catchments at Braes of Doune, central Scotland

    I. Grieve

    2008-07-01

    Full Text Available This paper assesses the impacts of disturbance associated with the construction of a wind farm on fluxes of dissolved organic carbon (DOC and suspended sediment from a blanket peat catchment in central Scotland during the period immediately following completion of construction. Six streams draining the site were sampled on six dates from October 2006, when construction was completed, and an additional three control streams to the west of the site were sampled on the same dates. Turbidity and stage were recorded semi-continuously in the two largest streams (one disturbed and one control, which were also sampled during storm events. Absorbance (400 nm and DOC concentrations were determined on all samples, and suspended sediment was determined on the event samples. Absorbance and DOC were closely correlated in both the disturbed and undisturbed streams, with slightly greater absorbance per unit DOC in the disturbed streams. DOC concentrations in disturbed tributaries were always greater than those in undisturbed streams, with mean differences ranging from 2 to around 5 mg L-1. DOC and stage were positively correlated during events with maximum concentrations in excess of 30 mg L 1 at peak flow. Suspended sediment concentrations were markedly elevated in the disturbed stream with maximum concentrations at peak flow some 4–5 times greater than in the control. The colour of the sediment suggested that it was highly organic in nature at peak flow, and suspended particulate organic carbon represented a further loss of C from the site. Using flow-weighted mean DOC concentrations calculated for the storms monitored in autumn 2007, dissolved carbon losses can be estimated for the catchments of the disturbed and control streams. From these data the additional DOC loss related to disturbance associated with the wind farm is estimated at 5 g m-2.

  7. MODIS-based retrieval of suspended sediment concentration and diffuse attenuation coefficient in Chinese estuarine and coastal waters

    Sokoletsky, Leonid; Yang, Xianping; Shen, Fang

    2014-11-01

    Radiative transfer modelling in atmosphere, water, and on the air-water surface was used to create an algorithm and computer code for satellite monitoring Chinese estuarine and coastal waters. The atmospheric part of the algorithm is based on the Reference Evaluation of Solar Transmittance (REST) model for calculation of optical properties of the atmosphere from the top of the atmosphere to the target; for modelling optical properties from target towards satellite's sensor, an optical reciprocity principle has been used. An algorithm uses estimates derived from three different sources: 1) the MODIS-based software; 2) radiative transfer equations, and 3) well-known empirical relationships between measured parameters and optical depths and transmittances for such atmospheric components as molecules, aerosols, ozone, nitrogen dioxide, precipitable water vapor and uniformly mixed gases. Using this model allowed us to derive a reliable relationship relating an important parameter, the diffuse-to-global solar incoming irradiance ratio, to the aerosol optical thickness, solar zenith angle and wavelength. The surface and underwater parts of the algorithm contained theoretical and semi-empirical relationships between inherent (such as absorption, scattering and backscattering coefficients) and apparent (remote-sensing reflectance and diffuse attenuation coefficient, Kd) optical properties, and suspended sediment concentration (SSC) measured in the Yangtze River Estuary and its adjacent coastal area. The first false colour maps of SSC and Kd demonstrated a well accordance with the multi-year field observations in the region, and suggest promise for use of this algorithm for the regular monitoring of Chinese and worldwide natural waters.

  8. Contributions To The Study Of Heavy Metals Concentration Variation In Sedimentable Dusts According To The Distance From The Pollution Source

    Mariana DOBRA

    2006-01-01

    Full Text Available The environment in areas where geological and mining activities, such as the extraction of ores containing heavy metals, take place, is heavily polluted with dusts resulting from these activities, as well as with residual waters from the mines. Depending on the meteorological conditions, as well as on the conditions under which sedimentable dusts or dusts in suspension are emitted into the air, the distance from the main pollution source varies considerably. In order to estimate the pollution level and the danger presented by this phenomenon, some analyses are required with regard to determining the concentration of heavy pollutant metals in air, soil and plants samples, as well as in dusts from the air. For the precise determination of the major components, as well as the minor ones, and also the ones in traces, the analytical techniques used must have low detection limits and the lowest matrix effects possible [1,2]. The methods that respond to these requirements are from the category of inductively coupled plasma atomic emission spectrometry (ICP-AES. The research was done in an area where there are industrial units whose main field of activity is extraction of certain ores which contain Pb, Cu and Zn as major components, as well as Cr, Mn, Ni, Co, Ag, Au, Al, and Fe as minor components or in traces. It is obvious that the presence of these metals in the air, water and soil has a negative impact on human health, plants and animals. This paper is a study of these aspects in an area where pollution with heavy metals reaches alarming quotas.

  9. The effects of unpaved roads on suspended sediment concentration of third- to fifth-order streams- A case study from southern Brazil

    Thomaz, E. L.; Vestena, L. R.; Ramos-Scharron, C. E.

    2012-12-01

    Unpaved roads have earned a reputation of inducing adverse effects on downstream water resources by increasing suspended sediment concentration because they typically generate sediment at rates up to several orders of magnitude above background and because they may enhance the efficiency of sediment delivery to fluvial networks. Although much research has been conducted on road effects in forested landscapes, proper understanding of their hydro-geomorphic role in rural areas is still desired. Unpaved roads are fundamental in the agricultural systems employed for the cultivation of maize and black beans on topographically-steep, marginal lands of southern Brazil. Marginal lands generate a sizeable fraction of the agricultural production in the state of Paraná, one of Brazil's agricultural powerhouses. This study documents the localized impacts on suspended sediment concentration of seven unpaved road crossings in the Guarabiroba River Catchment, Paraná, Brazil. A total of 156 suspended sediment samples were manually collected both upstream and downstream of road-crossings between 22-Apr-09 and 26-Apr-10 during 14 rainfall events ranging between 16 and 96 mm in total rainfall. The average length of road directly delivering runoff to each crossing varied from 0.56 - 2.4 km, and the size of the catchment areas of the third to fifth order monitored streams ranged from 0.3 to 13.5 km2. In addition to stream samples, 78 samples representing unpaved road runoff were collected during the same rain events. Upstream and downstream mean concentration values were compared for each storm at every site based on a paired t-test analysis (0.05% level). Mean suspended sediment concentration at stream segments located upstream of road crossings was 0.04 mg L-1 (s.d. = 0.05 mg L-1), while the mean downstream concentration was 0.11 mg L-1 (s.d. = 0.14 mg L-1) or 2.9 times higher than upstream samples. Meanwhile, road runoff had an average concentration of 0.93 mg L-1 (s.d. = 0.97 mg

  10. Microbial acetate oxidation in horizontal rotating tubular bioreactor

    A Slavica; B Šantek; S Novak; V Marić

    2004-06-01

    The aim of this work was to investigate the possibility of conducting a continuous aerobic bioprocess in a horizontal rotating tubular bioreactor (HRTB). Aerobic oxidation of acetate by the action of a mixed microbial culture was chosen as a model process. The microbial culture was not only grown in a suspension but also in the form of a biofilm on the interior surface of HRTB. Efficiency of the bioprocess was monitored by determination of the acetate concentration and chemical oxygen demand (COD). While acetate inlet concentration and feeding rate influenced efficiency of acetate oxidation, the bioreactor rotation speed did not influence the bioprocess dynamics significantly. Gradients of acetate concentration and pH along HRTB were more pronounced at lower feeding rates. Volumetric load of acetate was proved to be the most significant parameter. High volumetric loads (above 2 g acetate l–1 h–1) gave poor acetate oxidation efficiency (only 17 to 50%). When the volumetric load was in the range of 0.60–1.75 g acetate l–1 h–1, acetate oxidation efficiency was 50–75%. At lower volumetric loads (0.14–0.58 g acetate l–1 h–1), complete acetate consumption was achieved. On the basis of the obtained results, it can be concluded that HRTB is suitable for conducting aerobic continuous bioprocesses.

  11. Trace element concentrations in sediment and biota from the Benton Lake Wetland Management District, north-central Montana

    US Fish and Wildlife Service, Department of the Interior — This study was conducted to determine if trace elements are accumulating in either sediment or the aquatic food chain of water-bird habitats within the U.S. Fish...

  12. Petroleum hydrocarbon concentration in surface sediments in continental shelf region along the central west coast of India

    Ram, A.; Kadam, A.N.

    Gas chromatography revealed that nonpolar material extracted from surface sediments collected along the northern west coast of India was originated from petroleum hydrocarbon residue. Petroleum hydrocarbon levels as determinEd. by fluorescence...

  13. Characterization of heavy metal concentrations in the sediments of three freshwater rivers in Huludao City, Northeast China

    Wuli River, Cishan River, and Lianshan River are three freshwater rivers flowing through Huludao City, in a region of northeast China strongly affected by industrialization. Contamination assessment has never been conducted in a comprehensive way. For the first time, the contamination of three rivers impacted by different sources in the same city was compared. This work investigated the distribution and sources of Hg, Pb, Cd, Zn and Cu in the surface sediments of Wuli River, Cishan River, and Lianshan River, and assessed heavy metal toxicity risk with the application of two different sets of Sediment Quality Guideline (SQG) indices (effect range low/effect range median values, ERL/ERM; and threshold effect level/probable effect level, TEL/PEL). Furthermore, this study used a toxic unit approach to compare and gauge the individual and combined metal contamination for Hg, Pb, Cd, Zn and Cu. Results showed that Hg contamination in the sediments of Wuli River originated from previous sediment contamination of the chlor-alkali producing industry, and Pb, Cd, Zn and Cu contamination was mainly derived from atmospheric deposition and unknown small pollution sources. Heavy metal contamination to Cishan River sediments was mainly derived from Huludao Zinc Plant, while atmospheric deposition, sewage wastewater and unknown small pollution were the primary sources for Lianshan River. The potential acute toxicity in sediment of Wuli River may be primarily due to Hg contamination. Hg is the major toxicity contributor, accounting for 53.3-93.2%, 7.9-54.9% to total toxicity in Wuli River and Lianshan River, respectively, followed by Cd. In Cishan River, Cd is the major sediment toxicity contributor, however, accounting for 63.2-66.9% of total toxicity. - Sediment in Wuli River, Cishan River, and Lianshan River has been contaminated by heavy metals and adverse effects would be expected frequently in Wuli River and Cishan River

  14. Dose uniformity of loteprednol etabonate ophthalmic gel (0.5% compared with branded and generic prednisolone acetate ophthalmic suspension (1%

    Marlowe ZT

    2013-12-01

    Full Text Available Zora T Marlowe, Stephen R DavioPharmaceutical Product Development, Global Pharmaceutical Research and Development, Bausch and Lomb, Inc, Rochester, NY, USAIntroduction: Loteprednol etabonate (LE ophthalmic gel 0.5% (Lotemax® is a new polycarbophil-based, nonsettling topical ophthalmic formulation. The formulation is a semisolid gel at rest and a shear thinning fluid when expressed through a dropper tip. The present study was undertaken to determine how the nonsettling character of LE ophthalmic gel affects dose uniformity. Prednisolone acetate ophthalmic suspension 1% (Pred Forte® and a generic prednisolone acetate suspension 1% were used as comparators.Methods: Drug concentrations of LE ophthalmic gel, Pred Forte, and a generic prednisolone acetate suspension were determined following simulated dosing – consisting of 2 drops, expressed four times daily for 2 weeks, with bottles that were shaken or not shaken immediately prior to expressing the drops. Drug concentrations were determined using a reverse-phase high-performance liquid chromatography (HPLC method and reported as a percentage of the declared (labeled concentration. Comparative kinetics of drug particle sedimentation were also determined for each formulation, using dispersion analysis under gravity.Results: Mean drug concentrations in drops of all three formulations were within a few percentage points of the declared concentration when the bottles were shaken for 5 seconds prior to dispensing. Only LE ophthalmic gel showed consistent and on-target concentrations when the bottles were unshaken prior to dispensing, with a mean (standard deviation [SD] percent declared concentration of 102% (1.92% over the 2-week dosing regimen. Drug concentrations for the branded and generic prednisolone acetate suspensions following expression from unshaken bottles were highly variable (overall relative SDs of 16.8% and 20.3%, respectively, with mean concentrations for both falling significantly

  15. Uranium hydrogeochemical and stream sediment reconnaissance of the McGrath and Talkeetna NTMS Quadrangles, Alaska, including concentrations of forty-three additional elements

    During the summer of 1977, 1268 water and 1206 sediment samples were collected from 1292 lakes and streams throughout the two quadrangles in south-central Alaska. Each of the water samples was analyzed for uranium and 12 other elements and each of the sediment samples for uranium, thorium, and 41 other elements. Uranium concentrations in water samples range from below 0.02 ppB to 19.64 ppB. In general, lake waters contain somewhat less uranium than stream waters, and the highest concentrations in both sample types were found in or near the Alaska Range. Uranium concentrations in sediment samples range from 0.10 ppM to 172.40 ppM. The highest concentrations are found in samples collected in the Alaska Range near areas of felsic igneous rocks. Sediment samples having high thorium concentrations also come from areas underlain by felsic igneous rocks in the Alaska Range. The following areas were found to be most favorable for significant uranium mineralization: (1) the Windy Fork stock on the southeastern boundary of the McGrath quadrangle; (2) an area in the northwest corner of the Talkeetna quadrangle near the Mespelt prospects; (3) the Hidden River drainage in the northeast corner of the Talkeetna quadrangle; (4) an area near Chelatna Lake in the center of the Talkeetna quadrangle; (5) the Kichatna River drainage, near the western border of the Talkeetna quadrangle; and (6) an area near the Mount Estelle pluton in the extreme southwest corner of the Talkeetna quadrangle

  16. Geochemical provenance of anomalous metal concentrations in stream sediments in the Ashton 1:250,000 quadrangle, Idaho/Montana/Wyoming

    Stream-sediment samples from 1500 sites in the Ashton, Idaho/Montana/Wyoming 1:250,000 quadrangle were analyzed for 45 elements. Almost all samples containing anomalous concentrations (exceeding one standard deviation above the mean value of any element) were derived from drainage basins underlain by Quaternary rhyolite, Tertiary andesite or Precambrian gneiss and schist. Aluminum, barium, calcium, cobalt, iron, nickel, magnesium, scandium, sodium, strontium, and vanadium have no andesite provenance. Most anomalous manganese, europium, hafnium, and zirconium values were derived from Precambrian rocks. All other anomalous elemental concentrations are related to Quaternary rhyolite. This study demonstrates that multielemental stream-sediment analyses can be used to infer the provenance of stream sediments. Such data are available for many parts of the country as a result of the National Uranium Resource Evaluation. This study suggests that stream-sediment samples collected in the Rocky Mountains can be used either as pathfinders or as direct indicators to select targets for mineral exploration for a host of metals

  17. A passive sampler based on solid phase microextraction (SPME) for sediment-associated organic pollutants: Comparing freely-dissolved concentration with bioaccumulation.

    Maruya, Keith A; Lao, Wenjian; Tsukada, David; Diehl, Dario W

    2015-10-01

    The elevated occurrence of hydrophobic organic chemicals (HOCs) such as polycyclic aromatic hydrocarbons (PAH), polychlorinated biphenyls (PCBs) and legacy organchlorine pesticides (e.g. chlordane and DDT) in estuarine sediments continues to poses challenges for maintaining the health of aquatic ecosystems. Current efforts to develop and apply protective, science-based sediment quality regulations for impaired waterbodies are hampered by non-concordance between model predictions and measured bioaccumulation and toxicity. A passive sampler incorporating commercially available solid phase microextraction (SPME) fibers was employed in lab and field studies to measure the freely dissolved concentration of target HOCs (Cfree) and determine its suitability as a proxy for bioaccumulation. SPME deduced Cfree for organochlorines was highly correlated with tissue concentrations (Cb) of Macoma and Nereis spp. co-exposed in laboratory microcosms containing both spiked and naturally contaminated sediments. This positive association was also observed in situ for endemic bivalves, where SPME samplers were deployed for up to 1 month at an estuarine field site. The concordance between Cb and Cfree for PAH was more variable, in part due to likely biotransformation by model invertebrates. These results indicate that SPME passive samplers can serve as a proxy for bioaccumulation of sediment-associated organochlorines in both lab and field studies, reducing the uncertainty associated with model predictions that do not adequately account for differential bioavailability. PMID:26246043

  18. Cross-Validation of Suspended Sediment Concentrations Derived from Satellite Imagery and Numerical Modeling of the 1997 New Year's Flood on the Feather River, CA

    Kilham, N. E.

    2009-12-01

    Image analysis was applied to assess suspended sediment concentrations (SSC) predicted by a numerical model of 2D hydraulics and sediment transport (Telemac-2D), coupled to a solver for the advection-diffusion equation (SISYPHE) and representing 18 days of flooding over 70 kilometers of the lower Feather-Yuba Rivers. Sisyphe treats the suspended load as a tracer, removed from the flow if the bed shear velocity, u* is lower than an empirically derived threshold (ud* = 7.8E-3 m s-1). Agreement between model (D50 = 0.03 mm) and image-derived SSC (mg L-1) suggests that image interpretation could prove to be a viable approach for verifying spatially-distributed models of floodplain sediment transport if imagery is acquired for a particular flood and at a sufficient spatial and radiometric resolution. However, remotely derived SSC represents the integrated concentration of suspended sediment at the water surface. Hence, comparing SSC magnitudes derived from imagery and numerical modeling requires that a relationship is first established between the total suspended load and the portion of this load suspended within the optical range of the sensor (e.g., Aalto, 1995). Using the optical depth (0.5 m) determined from radiative transfer modeling, surface SSC measured from a 1/14/97 Landsat TM5 image (30 m) were converted to depth-integrated SSC with the Rouse (1937) equation. Surface concentrations were derived using a look-up table for the sensor to convert endmember fractions obtained from a spectral mixture analysis of the image. A two-endmember model (2.0 and 203 mg L-1) was used, with synthetic endmembers derived from optical and radiative transfer modeling and inversion of field spectra collected from the Sacramento and Feather Rivers and matched to measured SSC values. Remotely sensed SSC patterns were then compared to the Telemac results for the same day and time. Modeled concentrations are a function of both the rating curve boundary conditions, and the transport and

  19. Polycyclic aromatic hydrocarbons (PAHs) in plastic pellets: variability in the concentration and composition at different sediment depths in a sandy beach.

    Fisner, Mara; Taniguchi, Satie; Moreira, Fabiana; Bícego, Márcia C; Turra, Alexander

    2013-05-15

    Plastic pellets have the ability to adsorb organic pollutants such as PAHs. This study analyzed the variability in the concentration and composition of PAHs on plastic pellets sampled up to 1m deep in the sediment of a sandy beach. The toxic potential of PAHs was analyzed, and the possible sources of contamination are discussed. The total PAHs varied, with the highest concentrations in the surface layer; the priority PAHs showed a different pattern. PAHs at greater depths did not reach toxicity levels above the PEL. The composition of PAHs differed between pellets from the shallower and from deeper sediment layers, and was suggested a mixture of sources. These results provided the first information on the depth distribution of PAHs in sandy beaches, associated with plastic pellets; and evidenced the potential environmental risk. Similarly to the abundance of pellets, the toxic potential is underestimated in surface samples. PMID:23582976

  20. Quantifying sediment source contributions in coastal catchments impacted by the Fukushima nuclear accident with carbon and nitrogen elemental concentrations and stable isotope ratios

    Laceby, J. Patrick; Huon Huon, Sylvain; Onda, Yuichi; Evrard, Olivier

    2016-04-01

    The Fukushima Dai-ichi Nuclear Power Plant accidental release of radioactive contaminants resulted in the significant fallout of radiocesium over several coastal catchments in the Fukushima Prefecture. Radiocesium, considered to be the greatest risk to the short and long term health of the local community, is rapidly bound to fine soil particles and thus is mobilized and transported during soil erosion and runoff processes. As there has been a broad-scale decontamination of rice paddy fields and rural residential areas in the contaminated region, one important long term question is whether there is, or may be, a downstream transfer of radiocesium from forests that covered over 65% of the most contaminated region. Accordingly, carbon and nitrogen elemental concentrations and stable isotope ratios are used to determine the relative contributions of forests and rice paddies to transported sediment in three contaminated coastal catchments. Samples were taken from the three main identified sources: cultivated soils (rice paddies and fields, n=30), forest soils (n=45), and subsoils (channel bank and decontaminated soils, n = 25). Lag deposit sediment samples were obtained from five sampling campaigns that targeted the main hydrological events from October 2011 to October 2014. In total, 86 samples of deposited sediment were analyzed for particulate organic matter elemental concentrations and isotope ratios, 24 from the Mano catchment, 44 from the Niida catchment, and 18 from the Ota catchment. Mann-Whitney U-tests were used to examine the source discrimination potential of this tracing suite and select the appropriate tracers for modelling. The discriminant tracers were modelled with a concentration-dependent distribution mixing model. Preliminary results indicate that cultivated sources (predominantly rice paddies) contribute disproportionately more sediment per unit area than forested regions in these contaminated catchments. Future research will examine if there are

  1. Sulfate Reduction and Methanogenesis in the Sediment of a Saltmarsh on the East Coast of the United Kingdom

    Senior, Eric; Lindström, E. Börje; Banat, Ibrahim M.; Nedwell, David B.

    1982-01-01

    The rates of sulfate reduction, methanogenesis, and methane loss were measured in saltmarsh sediment at monthly intervals. In addition, dissolved methane and sulfate concentrations together with pS2− and pH were determined. Methane formation from carbon dioxide, but not from acetate, was detected within the same horizon of sediment where sulfate reduction was most active. Sulfate reduction was about three orders of magnitude greater than annual methanogenesis. The two processes were not separ...

  2. Assessments of radioactivity concentration of natural radionuclides and radiological hazard indices in sediment samples from the East coast of Tamilnadu, India with statistical approach

    Graphical abstract: Figure shows the clustering of radioactive variables. - Highlights: • The radiation hazard parameters were below the recommended values of safety limits. • Radiation hazard indices reflect study area become radiological safe to human beings. • Pearson correlation, PCA and HCA results are in good agreement with each other. - Abstract: This paper reports on the distribution of three natural radionuclides 238U, 232Th and 40K in coastal sediments from Pattipulam to Devanampattinam along the East coast of Tamilnadu to establish baseline data for future environmental monitoring. Sediment samples were collected by a Peterson grab samples from 10 m water depth parallel to the shore line. Concentration of natural radionuclides were determined using a NaI(Tl) detector based γ-spectrometry. The mean activity concentration is ⩽2.21, 14.29 and 360.23 Bq kg−1 for 238U, 232Th and 40K, respectively. The average activity of 232Th, 238U and 40K is lower when compared to the world average value. Radiological hazard parameters were estimated based on the activity concentrations of 238U, 232Th and 40K to find out any radiation hazard associated with the sediments. The radiological hazard parameters such as radium equivalent activity (Raeq), absorbed gamma dose rates in air (DR), the annual gonadal dose equivalent (AGDE), annual effective dose equivalent (AEDE), external hazard index (Hex) internal hazard index (Hin), activity utilization index (AUI) and excess lifetime cancer (ELCR) associated with the radionuclides were calculated and compared with internationally approved values and the recommended safety limits. Pearson correlation, principal component analysis (PCA) and hierarchical cluster analysis (HCA) have been applied in order to recognize and classify radiological parameters in sediments collected at 22 sites on East coast of Tamilnadu. The values of radiation hazard parameters were comparable to the world averages and below the recommended

  3. Evaluation of the activity concentration of 226Ra, 228Ra and 210Pb in sediments from Antarctica in the Admiralty bay region

    The natural radionuclides from radioactive series of 238U, 235U and 232Th have been applied as tracers in environmental studies for understanding the dynamics that occur in both marine and terrestrial environment, as for example, in research of oceanic processes and management of the coastal region. In the marine environment, these radionuclides can be used to estimate biogeochemical fluxes of marine particles and nutrients that occur in the water column as well as in the sediment. Several research works applied the distribution and the respective disequilibrium degree of natural radionuclides in the environment, including geochronological models for obtaining historical information on samples of certain sediment profile. In this study we performed a radiochemical characterization of the distribution of 226Ra, 228Ra and 210Pb from a sedimentary column called 1B (248 cm long) collected in the Admiralty Bay, Antarctic Peninsula region. The methodology used included the acid leaching of sediment samples followed by the radiochemical sequential separation of 226Ra and 228Ra by co-precipitation with Ba(Ra)SO4 and 210Pb by co-precipitation with PbCrO4. All measurements were carried out by counting of gross alpha and gross beta measures in a low background gas flow proportional detector. The activity concentrations of 226Ra and 210Pb were used to estimate the unsupported 210Pb activities present in sediment profile 1 B. Based on unsupported 210Pb data and the application of the CIC model (Constant Initial Concentration), it was possible to determine the sedimentation rate of 0.59 ± 0.05 cm /year. (author)

  4. Determination of natural radioactivity and the concentration of heavy metal in tissue of Guppy Fish, Poecilia Reticulata and sediment on urban drawn in Klang, Selangor

    This study has been carried out to determine the natural radioactivity and concentration of heavy metal in guppy fish, Poecilia Reticulata and sediment sample on urban drawn in Klang, Selangor. Natural radioactivity (U-238, Ra-226, Th-232 and K-40) was determined using gamma ray spectrometry. The concentration of heavy metal was determined using Coupled-Plasma Optical Emission Spectrometry (ICP-OES). Guppy fish and sediment sample was taken from three different locations in research area. Sample treatment process was starting with separation of impurities in sample. Samples were dried in the oven at 100 degree Celsius in 72 hours, homogenization process, and then samples were filled into counts bottles, sealed and kept for a month to achieved secular equilibrium. The activities found for each location varied. In sediment samples the activity concentration of U-238, Ra-226, Th-232 and K-40 were in the range of 87.61 ± 13.47 to 180.88 ± 30.50 Bq/ kg, 59.45 ± 9.12 to 88.29 ± 2.73 Bq/ kg, 6.70 ± 3.13 to 8.53 ± 4.90 Bq/ kg and 246.83 ± 12.27 to 495.28 ± 22.30 Bq/ kg. For sediment samples, have 12 elements of heavy metals found are Mg, K, Cr, Mn, Fe, Co, Cu, Zn, Al, As, Ba and Pb. For guppy fish, P. Reticulata have 7 elements of heavy metals achieved found are Mg, K, Mn, Fe, Cu, Zn and Al. Concentration of U-238 and K-40 is higher than the world average value reported by UNSCEAR (2000). Th-232 is below the world average value. From comparative with IAEA (1990) report showed that the concentration of heavy metals in sediment sample was at background level except for As and Pb. For concentration of heavy metal in guppy fish, P. Reticulata showed that the values are highly than value of IAEA-407 report except for Zn and Mn. (author)

  5. Carbon isotopes and iodine concentrations in a Mississippi River delta core recording land use, sediment transport, and dam building in the river's drainage basin.

    Santschi, Peter H; Oktay, Sarah D; Cifuentes, Luis

    2007-04-01

    Sedimentary material from coastal and nearshore areas in the Mississippi Delta region are comprised of different organic carbon sources with diverse ages that require isotopic and elemental records for resolving the various sources of plant residues. Carbon isotopic ((13)C, (14)C) values were used to differentiate contributions from plants using the C3, C4, and/or CAM (crassulacean acid metabolism) carbon fixation pathways., and iodine concentrations indicated that wetland plant residues are a significant source of organic carbon in a sediment core from the Mississippi River delta region collected at a 60 m water depth. This sediment core had been extensively described in Oktay et al. [Oktay, S.D., Santschi, P.H., Moran, J.E., Sharma, P., 2000. The (129)Iodine Bomb Pulse Recorded in Mississippi River delta Sediments: Results from Isotopes of I, Pu, Cs, Pb, and C. Geochim. Cosmochim. Acta 64 (6), 989-996.] and significantly, includes unique features that had not previously been seen in the marine environment. These special features include a plutonium isotopic close-in fallout record that indicates a purely terrestrial source for these sediment particles and the elements associated with it, and a distinct iodine isotopic peak (as well as peaks for plutonium and cesium isotopes) that indicate little bioturbation in this core. Our carbon isotopic and iodine data can thus be compared to published records of changes in drainage basin land use, river hydrology, and hydrodynamic sorting of suspended particles to elucidate if these changes are reflected in nearshore sediments. This comparison suggests a significant contribution for organic carbon (OC) from C4 plants to these sediments during the 1950's to early 1960's. Relative older carbon isotopes, and episodically high iodine concentrations (up to 34 ppm) were observed during this time period that (1) indicate sediment deposition that is coincident with the times of major hydrological changes induced from dam and levee

  6. Studies on the Gamma-Initiated Polymerization of Vinyl Acetate in Aqueous Media

    1. Gamma-initiated Polymerization of Vinyl Acetate in an Aqueous Solution of Uranyl Acetate. From a consideration of the rate and degree of polymerization of the gamma- initiated polymerization of vinyl-acetate in three systems (vinyl acetate-acetic acid, vinyl acetate-acetic acid, water, and vinyl acetate-acetic acid-water-uranyl acetate), the G-values of each component for the initiation of polymerization are estimated as follows G vinylacetateinitiation = 10,6; G aceticacidinitiation = 52; G waterinitiation = 480; G uranylacetateinitiation = 23,000. 2. Gamma-initiated Polymerization of Vinyl Acetate in Aqueous Solutions of Detergents. The emulsion polymerization of vinyl acetate in the presence of anionic, cationic and non ionic detergents is discussed. The rate is found to be greatest for the anionic detergent lauryl benzene sulphonate. The rate and degree of polymerization increase with detergent concentration. It is found that the rate of polymerization is ∝ (Intensity)0.25.

  7. Concentration and distribution patterns of naturally occurring radionuclides in sediments and flood plain soils of the catchment area of the river Elbe

    The impact of uranium mining and milling as well as that of traditional mining activities on river sediments and flood plain soils in the catchment area of the river Elbe was investigated over the years 1994 to 1995. Contamination resulting from mining activities has been identified by comparing the median values for the measured radionuclides, and by establishing the ratio between Ra-226 and Ra-228. The transport and deposition of contaminated materials as a result of high water events, and river discharge of waste water from mining and milling facilities, can be considered to be the main paths of sediment and soil contamination. Sediments and flood plain soils located in the vicinity of former uranium mining and milling sites are primarily influenced by discharges of waste water. Long distance transport and deposition at dams, barrages and on flood plains has mainly been caused by high water events. In many cases the radionuclide concentrations were higher in the subsurface layer than in the top layer of flood plain soil. Due to termination of uranium mining and milling activities, no significant contamination of newer or fresh sediments was found. Radiation exposure arising in relation to angling or walking on flood plains is low

  8. Mercury Concentrations in Fish and Sediment within Streams are Influenced by Watershed and Landscape Variables including Historical Gold Mining in the Sierra Nevada, California

    Alpers, C. N.; Yee, J. L.; Ackerman, J. T.; Orlando, J. L.; Slotton, D. G.; Marvin-DiPasquale, M. C.

    2015-12-01

    We compiled available data on total mercury (THg) and methylmercury (MeHg) concentrations in fish tissue and streambed sediment from stream sites in the Sierra Nevada, California, to assess whether spatial data, including information on historical mining, can be used to make robust predictions of fish fillet tissue THg concentrations. A total of 1,271 fish from five species collected at 103 sites during 1980-2012 were used for the modeling effort: 210 brown trout, 710 rainbow trout, 79 Sacramento pikeminnow, 93 Sacramento sucker, and 179 smallmouth bass. Sediment data were used from 73 sites, including 106 analyses of THg and 77 analyses of MeHg. The dataset included 391 fish (mostly rainbow trout) and 28 sediment samples collected explicitly for this study during 2011-12. Spatial data on historical mining included the USGS Mineral Resources Data System and publicly available maps and satellite photos showing the areas of hydraulic mine pits and other placer mines. Modeling was done using multivariate linear regression and multi-model inference using Akaike Information Criteria. Results indicate that fish THg, accounting for species and length, can be predicted using geospatial data on mining history together with other landscape characteristics including land use/land cover. A model requiring only geospatial data, with an R2 value of 0.61, predicted fish THg correctly with respect to over-or-under 0.2 μg/g wet weight (a California regulatory threshold) for 108 of 121 (89 %) size-species combinations tested. Data for THg in streambed sediment did not improve the geospatial-only model. However, data for sediment MeHg, loss on ignition (organic content), and percent of sediment less than 0.063 mm resulted in a slightly improved model, with an R2 value of 0.63. It is anticipated that these models will be useful to the State of California and others to predict areas where mercury concentrations in fish are likely to exceed regulatory criteria.

  9. Influence of Reservoir Water Level Fluctuations on Sediment Methylmercury Concentrations Downstream of the Historical Black Butte Mercury Mine, OR

    Mercury (Hg) is a pollutant of global concern due to its ability to accumulate as methylmercury (MeHg) in biota. Mercury is methylated by anaerobic microorganisms such as sulfate reducing bacteria (SRB) in water and sediment. Throughout North America, reservoirs tend to have e...

  10. The last 41.000 years fluctuation in atmospheric CO2 concentration inferred from the changes in oxygen and carbon stable isotopes ratios of marine sediments

    The past atmospheric CO2 concentrations were reconstructed based on the results of measurements of stable oxygen and carbon isotopic ratios of fossil foraminifera and total organic carbon contained in marine sediment taken from the Okinawa Trough. East China Sea. In' this study, we utilized two models of Popp et al and Rau et al, for the reconstruction. The results show that the whole trends of the changes in CO2 concentrations are very similar, even when it is compared to the atmospheric CO2 concentration of air trapped in ice core from southern pole. Changes in atmospheric CO2 concentrations are interpreted as a consequence of fluctuation in ocean surface water utilization of CO2 by marine organism and those are closely related to glacial interglacial (cold-warm) fluctuations between maximum and minimum values through most Quaternary. (author)

  11. Ecotoxicological response of marine organisms to inorganic and organic sediment amendments in laboratory exposures.

    Rosen, Gunther; Leather, James; Kan, Jinjun; Arias-Thode, Yolanda Meriah

    2011-10-01

    Experimental materials currently being investigated for use as amendments for the in situ remediation of contaminated sediments were assessed for their potential impacts on marine benthos. Laboratory toxicity tests involving lethal and sublethal endpoints were conducted on sediments amended with apatite, organoclay, chitin, or acetate, with the polychaete Neanthes arenaceodentata, the amphipod Eohaustorius estuarius, and the larval sheepshead minnow Cyprinodon variegatus. Amendments were mixed loosely into uncontaminated or metal-contaminated sediments, and also added inside experimental geotextile mats, at sediment dry weight (dw) concentrations ranging from 0.5% to 10%. The geotextile mats, containing apatite (5 or 10% dw), and/or organoclay (5%) did not result in adverse effects on any of the test organisms. Chitin and acetate, however, repetitively resulted in adverse effects on survival and/or adverse or positive effects on organism growth at concentrations of ≤ 2.5% dw. The adverse effects were attributed to water quality degradation in the exposure vessels (notably ammonia and dissolved oxygen concentration, for chitin and acetate, respectively) as a result of the microbial breakdown of the amendments. For N. arenaceodentata, growth was enhanced in the presence of chitin at concentrations as low as 0.5% sediment dw, which stimulated bacterial growth that may have provided an additional food source for the polychaete. Sediment chitin concentrations of 0.5% resulted in a statistically significant reduction in N. arenaceodentata body burdens of 61%, 29%, and 54%, relative to unamended contaminated sediment, for Cu, Zn, and Cd, respectively. The studies suggest a lack of inherent toxicity of these materials on the experimental organisms, as the adverse or positive responses observed are likely related to artifacts associated with laboratory exposure. Assessments in field settings are needed to verify this conclusion. PMID:21840599

  12. Acetate availability and its influence on sustainable bioremediation of uranium-contaminated groundwater

    Field biostimulation experiments at the U.S. Department of Energy's Integrated Field Research Challenge (IFRC) site in Rifle, Colorado, have demonstrated that uranium concentrations in groundwater can be decreased to levels below the U.S. Environmental Protection Agency's (EPA) drinking water standard (0.126 (micro)M). During successive summer experiments - referred to as 'Winchester' (2007) and 'Big Rusty' (2008) - acetate was added to the aquifer to stimulate the activity of indigenous dissimilatory metal-reducing bacteria capable of reductively immobilizing uranium. The two experiments differed in the length of injection (31 vs. 110 days), the maximum concentration of acetate (5 vs. 30 mM), and the extent to which iron reduction ('Winchester') or sulfate reduction ('Big Rusty') was the predominant metabolic process. In both cases, rapid removal of U(VI) from groundwater occurred at calcium concentrations (6 mM) and carbonate alkalinities (8 meq/L) where Ca-UO2-CO3 ternary complexes constitute >90% of uranyl species in groundwater. Complete consumption of acetate and increased alkalinity (>30 meq/L) accompanying the onset of sulfate reduction corresponded to temporary increases in U(VI); however, by increasing acetate concentrations in excess of available sulfate (10 mM), low U(VI) concentrations (0.1-0.05 (micro)M) were achieved for extended periods of time (>140 days). Uniform delivery of acetate during 'Big Rusty' was impeded due to decreases in injection well permeability, likely resulting from biomass accumulation and carbonate and sulfide mineral precipitation. Such decreases were not observed during the short-duration 'Winchester' experiment. Terminal restriction fragment length polymorphism (TRFLP) analysis of 16S rRNA genes demonstrated that Geobacter sp. and Geobacter-like strains dominated the groundwater community profile during iron reduction, with 13C stable isotope probing (SIP) results confirming these strains were actively utilizing acetate to

  13. Acetate availability and its influence on sustainable bioremediation of Uranium-contaminated groundwater

    Williams, K.H.; Long, P.E.; Davis, J.A.; Wilkins, M.J.; N'Guessan, A. L.; Steefel, Carl; Yang, L.; Newcomer, D.; Spane, F.A.; Kerkhof, L.J.; Mcguinness, L.; Dayvault, R.; Lovley, D.R.

    2011-01-01

    Field biostimulation experiments at the U.S. Department of Energy's Integrated Field Research Challenge (IFRC) site in Rifle, Colorado, have demonstrated that uranium concentrations in groundwater can be decreased to levels below the U.S. Environmental Protection Agency's (EPA) drinking water standard (0.126??M).During successive summer experiments - referred to as "Winchester" (2007) and "Big Rusty" (2008) - acetate was added to the aquifer to stimulate the activity of indigenous dissimilatory metal reducing bacteria capable of reductively immobilizing uranium. The two experiments differed in the length of injection (31 vs. 110 days), the maximum concentration of acetate (5 vs. 30 mM),and the extent to which iron reduction ("Winchester") or sulfate reduction("Big Rusty") was the predominant metabolic process. In both cases, rapid removal of U(VI) from groundwater occurred at calcium concentrations (6 mM) and carbonate alkalinities (8 meq/L) where Ca-UO2-CO3 ternary complexes constitute >90% of uranyl species in groundwater. Complete consumption of acetate and increased alkalinity (>30 meq/L) accompanying the onset of sulfate reduction corresponded to temporary increases in U(VI);however, by increasing acetate concentrations in excess of available sulfate (10 mM), low U(VI) concentrations (0.1-0.05 ??M) were achieved for extended periods of time (>140 days). Uniform delivery of acetate during "Big Rusty" was impeded due to decreases in injection well permeability, likely resulting from biomass accumulation and carbonate and sulfide mineral precipitation. Such decreases were not observed during the short-duration "Winchester" experiment. Terminal restriction fragment length polymorphism (TRFLP) analysis of 16S rRNA genes demonstrated that Geobacter sp. and Geobacter-like strains dominated the groundwater community profile during iron reduction, with 13C stable isotope probing (SIP) results confirming these strains were actively utilizing acetate to replicate their

  14. Mercury(II) Acetate

    Dejmek, Milan

    2012-01-01

    Roč. 23, č. 19 (2012), s. 2867-2868. ISSN 0936-5214 Institutional support: RVO:61388963 Keywords : mercury(II) acetate * oxymercuration Subject RIV: CC - Organic Chemistry Impact factor: 2.655, year: 2012

  15. An investigation of spatial variation of suspended sediment concentration induced by a bay bridge based on Landsat TM and OLI data

    Cai, LiNa; Tang, DanLing; Li, CongYing

    2015-07-01

    This study investigates the spatial variation of suspended sediment concentration (SSC) induced by Hangzhou Bay Bridge (HBB) in the coastal waters of the East China Sea. Based on Landsat Thematic Mapper (TM), Operational Land Imager (OLI) data and in-situ measurements, spectral characteristics of waters in Hangzhou Bay and SSC retrieved from near infrared single band have been analyzed. The results revealed significant difference of SSC in the water on two sides of HBB. SSC increases downstream of the bridge under conditions of low turbidity (SSC 400 mg l-1) upstream. This study shows that the interaction of bridge piers and currents has important influences on SSC distribution by inducing hydrodynamic factors and by changing suspended sediment transport. Remotely sensed data with high spatial resolution as TM and OLI can be applied to investigate SSC variations induced by a bridge in the bay area.

  16. Activity concentration and spatial distribution of radionuclides in marine sediments close to the estuary of Shatt al-Arab/Arvand Rud River, the Gulf.

    Patiris, D L; Tsabaris, C; Anagnostou, C L; Androulakaki, E G; Pappa, F K; Eleftheriou, G; Sgouros, G

    2016-06-01

    Tigris and Euphrates rivers both emerge in eastern Turkey and cross Syria and Iraq. They unite to Shatt al-Arab/Arvand Rud River and discharge in Arabic/Persian Gulf. The activity concentration of natural and anthropogenic radionuclides was measured during the August of 2011 in a number of surficial sediment samples collected from the seabed along an almost straight line beginning near the estuary mouth and extending seaward. The results exhibited low activity concentration levels and an almost homogeneous spatial distribution except locations where sediment of biogenic origin, poor in radionuclides, dilute their concentrations. Dose rates absorbed by reference marine biota were calculated by the ERICA Assessment Tool considering the contribution of 40 K. The results revealed a relatively low impact of 40 K mainly to species living in, on and close to the seabed. Also, statistical association of radionuclides with selected stable elements (Ca, Ba and Sr) did not indicate presence of by-products related with oil and gas exploitation and transportation activities. Moreover, a semi-empirical sedimentology model applied to reproduce seabed granulometric facies based entirely on radionuclides activity concentrations. PMID:26945883

  17. Dietary assimilation of cadmium associated with bacterial exopolymer sediment coatings by the estuarine amphipod Leptocheirus plumulosus: Effects of Cd concentration and salinity

    Schlekat, C.E.; Decho, Alan W.; Chandler, G.T.

    1999-01-01

    Bacterial extracellular substances (also known as exopolysaccharides, or EPS) may serve as vectors for trophic transfer of metals in benthic systems because these ubiquitous sediment coatings can sorb high concentrations of toxic metals, and because many benthic invertebrates assimilate EPS sediment coatings upon ingestion. We conducted 3 sets of experiments to determine the assimilative bioavailability of EPS-associated Cd to the benthic amphipod Leptocheirus plumulosus as a function of Cd concentration and salinity. Bioavailability was measured as L. plumulosus Cd assimilation efficiency (AE) from EPS-coated silica (EPS-Si) and from uncoated silica (NC-Si) using modified pulse-chase methods with the gamma-emitting radioisotope 109Cd. Cd AE was significantly greater from NC-Si than from EPS-Si at 7.5???, but not at 2.5 or 25???. Overall, Cd AE from EPS-Si was between 15.1 and 21.5%. Because EPS-Si sorbed more Cd than NC-Si, EPS coatings magnified the amount of Cd amphipods accumulated at each salinity by up to a factor of 10. Salinity did not directly affect Cd AE from EPS-Si, but because Cd-EPS partitioning increased with decreasing salinity, amphipods accumulated more Cd from EPS at the lowest Cd-EPS incubation salinity (2.5 ???) than at higher salinities (7.5 and 25 ???). Finally, Cd concentration in EPS exhibited an inverse relationship with Cd AE at 2.5 ???, but not at 25 ???. Specifically, Cd AE was 12 times greater at 1 compared with 10 ??g Cd ??g-1 EPS. Together, these results show that estuarine benthos can accumulate Cd from EPS sediment coatings, but that the degree to which this phenomenon occurs is dependent upon seawater salinity and Cd concentration in EPS.

  18. Proposal of reference concentration values for metals and metalloids in limnic and fluvial sediments of Tiete River, Sao Paulo State, Brazil

    This project represents the first efforts in Brazil in the proposition and establishment of reference concentration values for metals and metalloids in limnic and fluvial sediments. The selected study site is the Tiete river basin (Sao Paulo state, southeast region), a watershed which is under significant environmental impact and degradation since the onset of the Brazilian revolution at early-mid 50's. In order to consolidate the analytical values 1,100 analyses were performed encompassing 95 sampling points in 29 municipalities, from the upper stream parts of the river down to its mouth at the Parana river, covering an extension of approximate 800 km. Sediment samples were collected in small streams and rivers as closest as possible to their upper reaches, as well as in rivers and reservoirs in locations minimally affected by human contamination. Samples were initially sieved for separation of the particles 3, HF, HClO4 and HCl). Chemical analyses were performed by induced coupled plasma atomic emission spectrometry for Cr, Ti, Zn, and V, and via atomic absorption spectrometry using conventional flame for Co, Cu, Ni and Pb, graphite furnace for Cd and Ag, hydride generation for As and Se, and cold vapor for Hg. U and Th were analysed by molecular absorption spectrophotometry using the chromogenic reagent Arsenazo III. The referent concentrations determined by this study showed significant differences with respect to the assumed global geological reference for some elements; differences were also detected among the concentrations of the same element from different basin regions and are attributed to differences in regional geochemical characteristics. As a consequence of these lithological variations, four different sets of reference concentration values are proposed valid to the different regions of the studied basin. This study also presents application of different sediment quality classifications models and potential ecological risk index for Bariri, Billings

  19. Translocation of Cd and Mn from Bark to Leaves in Willows on Contaminated Sediments: Delayed Budburst Is Related to High Mn Concentrations

    Bart Vandecasteele

    2015-04-01

    Full Text Available Changes in the hydrology of sediments in tidal marshes or landfills may affect the uptake of metals in the vegetation. Leaf and stem samples of Salix cinerea (grey sallow were collected during four consecutive growing seasons at six contaminated plots on a polluted dredged sediment landfill and one plot on an uncontaminated reference site. The first three contaminated plots were already emerged in the first half of the first growing season, while the other three were submerged in the first year, but became increasingly dry over the study period. Foliar and stem cutting concentrations for Cd, Zn and Mn increased on the latter three plots over the four years. Willow bark contained high concentrations of Cd, Zn and Mn. In two consecutive greenhouse experiments with willow cuttings from different origins (uncontaminated and contaminated sites and grown under different soil conditions (uncontaminated and contaminated, we observed an important translocation of Mn from bark to shoots. In a third experiment with willow cuttings collected on soils with a range of heavy metal concentrations and, thus, with a broad range of Cd (4–67 mg/kg dry matter, Zn (247–660 mg/kg dry matter and Mn (38–524 mg/kg dry matter concentrations in the bark, high Mn concentrations in the bark were found to affect the budburst of willow cuttings, while no association of delayed budburst with Cd and Zn concentrations in the bark was found. We conclude that wood and, especially, bark are not a sink for metals in living willows. The high Mn concentrations in the bark directly or indirectly caused delayed or restricted budburst of the willow cuttings.

  20. Application of a Weighted Regression Model for Reporting Nutrient and Sediment Concentrations, Fluxes, and Trends in Concentration and Flux for the Chesapeake Bay Nontidal Water-Quality Monitoring Network, Results Through Water Year 2012

    Chanat, Jeffrey G.; Moyer, Douglas L.; Blomquist, Joel D.; Hyer, Kenneth E.; Langland, Michael J.

    2016-01-01

    In the Chesapeake Bay watershed, estimated fluxes of nutrients and sediment from the bay’s nontidal tributaries into the estuary are the foundation of decision making to meet reductions prescribed by the Chesapeake Bay Total Maximum Daily Load (TMDL) and are often the basis for refining scientific understanding of the watershed-scale processes that influence the delivery of these constituents to the bay. Two regression-based flux and trend estimation models, ESTIMATOR and Weighted Regressions on Time, Discharge, and Season (WRTDS), were compared using data from 80 watersheds in the Chesapeake Bay Nontidal Water-Quality Monitoring Network (CBNTN). The watersheds range in size from 62 to 70,189 square kilometers and record lengths range from 6 to 28 years. ESTIMATOR is a constant-parameter model that estimates trends only in concentration; WRTDS uses variable parameters estimated with weighted regression, and estimates trends in both concentration and flux. WRTDS had greater explanatory power than ESTIMATOR, with the greatest degree of improvement evident for records longer than 25 years (30 stations; improvement in median model R2= 0.06 for total nitrogen, 0.08 for total phosphorus, and 0.05 for sediment) and the least degree of improvement for records of less than 10 years, for which the two models performed nearly equally. Flux bias statistics were comparable or lower (more favorable) for WRTDS for any record length; for 30 stations with records longer than 25 years, the greatest degree of improvement was evident for sediment (decrease of 0.17 in median statistic) and total phosphorus (decrease of 0.05). The overall between-station pattern in concentration trend direction and magnitude for all constituents was roughly similar for both models. A detailed case study revealed that trends in concentration estimated by WRTDS can operationally be viewed as a less-constrained equivalent to trends in concentration estimated by ESTIMATOR. Estimates of annual mean flow

  1. Acetic acid removal from corn stover hydrolysate using ethyl acetate and the impact on Saccharomyces cerevisiae bioethanol fermentation.

    Aghazadeh, Mahdieh; Ladisch, Michael R; Engelberth, Abigail S

    2016-07-01

    Acetic acid is introduced into cellulose conversion processes as a consequence of composition of lignocellulose feedstocks, causing significant inhibition of adapted, genetically modified and wild-type S. cerevisiae in bioethanol fermentation. While adaptation or modification of yeast may reduce inhibition, the most effective approach is to remove the acetic acid prior to fermentation. This work addresses liquid-liquid extraction of acetic acid from biomass hydrolysate through a pathway that mitigates acetic acid inhibition while avoiding the negative effects of the extractant, which itself may exhibit inhibition. Candidate solvents were selected using simulation results from Aspen Plus™, based on their ability to extract acetic acid which was confirmed by experimentation. All solvents showed varying degrees of toxicity toward yeast, but the relative volatility of ethyl acetate enabled its use as simple vacuum evaporation could reduce small concentrations of aqueous ethyl acetate to minimally inhibitory levels. The toxicity threshold of ethyl acetate, in the presence of acetic acid, was found to be 10 g L(-1) . The fermentation was enhanced by extracting 90% of the acetic acid using ethyl acetate, followed by vacuum evaporation to remove 88% removal of residual ethyl acetate along with 10% of the broth. NRRL Y-1546 yeast was used to demonstrate a 13% increase in concentration, 14% in ethanol specific production rate, and 11% ethanol yield. This study demonstrated that extraction of acetic acid with ethyl acetate followed by evaporative removal of ethyl acetate from the raffinate phase has potential to significantly enhance ethanol fermentation in a corn stover bioethanol facility. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:929-937, 2016. PMID:27090191

  2. A three-band semi-analytical model for deriving total suspended sediment concentration from HJ-1A/CCD data in turbid coastal waters

    Chen, Jun; Cui, Tingwei; Qiu, Zhongfeng; Lin, Changsong

    2014-07-01

    The accurate assessment of total suspended sediment (TSM) concentration in coastal waters by means of remote sensing is quite challenging, due to the optical complexity and significant variability of these waters. In this study, three-band semi-analytical TSM retrieval (TSTM) model with HJ-1A/CCD spectral bands was developed for the retrieval of TSM concentration from turbid coastal waters. This model was calibrated and validated by means of one calibration dataset and three independent validation datasets obtained from three different turbid waters. It was found that the TSTM model may be used to retrieve accurate TSM concentration data from highly turbid waters without the spectral slope of the model requiring further optimization. Finally, the TSM concentration data were quantified from the HJ-1A/CCD images after atmospheric correction using the dark-object subtraction technique. Upon comparing the model-derived and field-measured TSM concentration data, it was observed that the TSTM model produced <29% uncertainty in deriving TSM concentration from the HJ-1A/CCD data. These findings imply that the TSTM model may be used for the quantitative monitoring of TSM concentration in coastal waters, provided that the atmospheric correction scheme for the HJ-1A/CCD imagery is available.

  3. Concentration of heavy metal As, Pb, Mn, Ni, Sn, Zn, Cr, Fe and radon gas in bottom sediment from abandoned tin mines in the Phuket Province

    Suteerasak, T.

    2006-05-01

    Full Text Available This research is aimed at analyzing the heavy metals: As, Pb, Mn, Ni, Sn, Zn, Cr, Fe, and radon gas emission in bottom sediment from six abandoned tin mines in Phuket Province. Fe, Mn, and Sn were found in higher concentrations (but non-polluting than Cr and Ni. As, Pb, and Zn were polluting at lower levels. The concentration ranges for As, Pb, and Zn were 75.3-169, 98.6-547.5, and 120.4-323.3 mg/kg respectively. The activity of radon gas emission from bottom sediment from an abandoned tin mine in Amphur Muang was in the range of 162-212 Bq/kg., in the Amphur Katoo mine the range was 122-266 Bq/kg. and in the Amphur Talang mine the range was 180-263 Bq/kg. All these sites have higher concentrations of radon gas emissions than other similar sites. The heavy metals and radon gas come from geochemical materials such as soil and granite rock, found around the abandoned tin mines.

  4. Variations in selected water quality variables and metal concentrations in the sediment of the lower Olifants and Selati rivers, South Africa

    T. Seymore

    1994-09-01

    Full Text Available A survey of the water and sediment quality of the lower Olifants River and lower Selati River was carried out. Metal concentrations (Cr, Cu, Fe, Mn, Ni, Pb, Sr and Zn in the water and sediment, as well as the physical and chemical characteristics of the water were determined over a two-year period (April 1990 - February 1992. The water quality of the lower Selati River, which flows through the Phalaborwa area, was found to be influenced by the mining and industrial activities in the area. It was also the case with the lower Olifants River after the Selati-Olifants confluence, although the concentrations of most variables did decrease from the western side of the Kruger National Park to the eastern side due to dilution of the water by tributaries of the Olifants River. Variables of special concern were sodium, fluoride. chloride, sulphate, potassium, the total dissolved salts and the metal concentrations (except strontium. The water quality of the Selati River in the study area is a great cause of concern and a further degradation thereof cannot be afforded.

  5. National Geochemical Database: Sediment

    U.S. Geological Survey, Department of the Interior — Geochemical analysis of sediment samples from the National Geochemical Database. Primarily inorganic elemental concentrations, most samples are of stream sediment...

  6. Interpretation of geochemical data from panned concentrates of wadi sediments using R-mode factor analysis, Jabal Habashi Quadrangle, sheet 26F, Kingdom of Saudi Arabia

    Allen, M.S.; Tidball, R.R.; Samater, R.M.; Selner, G.I.

    1985-01-01

    Panned-concentrate samples from wadi sediments were collected over terranes of Precambrian age intrusive, volcanic, sedimentary, and metamorphic rocks, within the Jabal Habashi quadrangle, sheet 26F, Kingdom of Saudi Arabia. Multivariate analysis of the chemical data indicates that a significant base-metal association occurs in three areas within the quadrangle. An association of strontium, barium, and calcium possibly indicates areas of hydrothermal alteration. Three other associations that were found define the major rock lithologies: niobium-yttrium-lanthanum outlines granitic terranes; magnesium-nickel indicates mafic rocks; and cobalt-vanadium-chromium have an indefinite relation with units mapped as graywacke in the central part of the quadrangle.

  7. Concentrations and Fractionation of Carbon, Iron, Sulfur, Nitrogen and Phosphorus in Mangrove Sediments Along an Intertidal Gradient (Semi-Arid Climate, New Caledonia

    Jonathan Deborde

    2015-02-01

    Full Text Available In mangrove ecosystems, strong reciprocal interactions exist between plant and substrate. Under semi-arid climate, Rhizophora spp. are usually predominant, colonizing the seashore, and Avicennia marina develops at the edge of salt-flats, which is the highest zone in the intertidal range. Along this zonation, distribution and speciation of C, Fe, S, N, and P in sediments and pore-waters were investigated. From the land-side to the sea-side of the mangrove, sediments were characterized by I/ increase in: (i water content; (ii TOC; (iii mangrove-derived OM; II/ and decrease in: (i salinity; (ii redox; (iii pH; (iv solid Fe and solid P. Beneath Avicennia and Rhizophora, TS accumulated at depth, probably as a result of reduction of iron oxides and sulfate. The loss of total Fe observed towards the sea-side may be related to sulfur oxidation and to more intense tidal flushing of dissolved components. Except the organic forms, dissolved N and P concentrations were very low beneath Avicennia and Rhizophora stands, probably as a result of their uptake by the root systems. However, in the unvegetated salt-flat, NH4+ can accumulate in organic rich and anoxic layers. This study shows: (i the evolution of mangrove sediment biogeochemistry along the intertidal zone as a result of the different duration of tidal inundation and organic enrichment; and (ii the strong links between the distribution and speciation of the different elements.

  8. Evaluating the techniques for a tiered testing approach to dredged sediment assessment--a study over a metal concentration gradient

    Porebski, L.M.; Doe, K.G.; Zajdlik, B.A.; Lee, D.; Pocklington, P.; Osborne, J.M.

    1999-11-01

    A sediment quality triad approach was used to evaluate Environment Canada's battery of marine bioassays and the proposed pass/fail criteria along a metals gradient in Belledune Harbour, New Brunswick, Canada. Most assays performed consistently, but certain tests provided less response than expected at the more contaminated stations (amphipod survival and light reduction in photoluminescent bacteria tests passed according to proposed pass/fail criteria). Echinoid fertilization tests were quite sensitive. Bioaccumulation of lead and benthic community structure were related to bulk sediment values. Test interpretation criteria appear reasonable, but as the response rate was low in certain tests, further assessment is recommended. With respect to species suitability, only the clam Macoma balthica used in the bioaccumulation test was thought to be less than optimal for routine use on a large scale because of practical handling and cost considerations. Canadian draft Interim Sediment Quality Guidelines, which the Disposal at Sea Program may use for screening purposes in a tiered testing approach, were used in this study as the chemical benchmarks to select test stations on the basis of the relative probability of effects. Guidelines at the threshold effects level (TEL) performed well in the study as levels below which unacceptable biological effects were unlikely to occur. The ratio of simultaneously extractable metals to acid volatile sulfides was also used in addition to the guideline levels to help explain responses (or lack thereof) along the gradient. Each of the chemical approaches was useful in the prediction/explanation of some but not all of the responses seen in the toxicity and/or benthic community results.

  9. Comparison of fluvial suspended-sediment concentrations and particle-size distributions measured with in-stream laser diffraction and in physical samples

    Czuba, Jonathan A.; Straub, Timothy D.; Curran, Christopher A.; Landers, Mark N.; Domanski, Marian M.

    2014-01-01

    Laser-diffraction technology, recently adapted for in-stream measurement of fluvial suspended-sediment concentrations (SSCs) and particle-size distributions (PSDs), was tested with a streamlined (SL), isokinetic version of the Laser In-Situ Scattering and Transmissometry (LISST) for measuring volumetric SSCs and PSDs ranging from 1.8-415 µm in 32 log-spaced size classes. Measured SSCs and PSDs from the LISST-SL were compared to a suite of 22 datasets (262 samples in all) of concurrent suspended-sediment and streamflow measurements using a physical sampler and acoustic Doppler current profiler collected during 2010-12 at 16 U.S. Geological Survey streamflow-gaging stations in Illinois and Washington (basin areas: 38 – 69,264 km2). An unrealistically low computed effective density (mass SSC / volumetric SSC) of 1.24 g/ml (95% confidence interval: 1.05-1.45 g/ml) provided the best-fit value (R2 = 0.95; RMSE = 143 mg/L) for converting volumetric SSC to mass SSC for over 2 orders of magnitude of SSC (12-2,170 mg/L; covering a substantial range of SSC that can be measured by the LISST-SL) despite being substantially lower than the sediment particle density of 2.67 g/ml (range: 2.56-2.87 g/ml, 23 samples). The PSDs measured by the LISST-SL were in good agreement with those derived from physical samples over the LISST-SL's measureable size range. Technical and operational limitations of the LISST-SL are provided to facilitate the collection of more accurate data in the future. Additionally, the spatial and temporal variability of SSC and PSD measured by the LISST-SL is briefly described to motivate its potential for advancing our understanding of suspended-sediment transport by rivers.

  10. Concentration of lead, cadmium, and iron in sediment dust and total suspended particles before and after initialisation of integral production in iron and steel work plant Zenica.

    Prcanović, Halim; Duraković, Mirnes; Beganović, Sanela

    2012-06-01

    Poor air quality is a common fact for all areas with base industry. The city of Zenica was once the metallurgical centre of Ex-Yugoslavia and is therefore highly polluted at present. Air pollution peaked in 1987 when average concentration of pollutants was extremely high (daily average concentration of SO(2) was 1800 μg m(-3)). With the beginning of the war in 1992, integral production in the steel work plant was shut down, to be re-launched in 2008. Limit values for iron do not exist, but iron has been monitored in Zenica for the past 28 years because of the presence of steel works. Concentrations of cadmium and lead have also been measured because they are very much present in polluted areas with steel works. The concentration of mentioned elements in air deposit and total suspended particles before and after integral production in the steel work plant was re-launched is the subject of this paper. Total suspended particles were measured in two locations using German standard VDI 2463 Blatt 4. Sediment dust was measured in nine locations using Bergerhoff method. The concentration of iron, lead, and cadmium was performed in the chemical laboratory of the Metallurgical Institute "Kemal Kapetanović" Zenica using standard methods. Higher concentrations of these parameters during the period of integral production clearly point to the impact of steel works on Zenica valley. PMID:22728800

  11. The geostatistics of the metal concentrations in sediments from the eastern Brazilian continental shelf in areas of gas and oil production

    Aguiar, Jose Edvar; de Lacerda, Luiz Drude; Miguens, Flavio Costa; Marins, Rozane Valente

    2014-04-01

    Geostatistical techniques were used to evaluate the differences in the geochemistry of metals in the marine sediments along the Eastern Brazilian continental margin along the states of Ceará and Rio Grande do Norte (Northeastern sector) and Espírito Santo (Southeastern sector). The concentrations of Al, Fe, Mn, Ba, Cd, Cu, Cr, Ni, Pb, V, Hg, and Zn were obtained from acid digestion and quantified using flame atomic absorption spectrometry (AAS), inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma atomic emission spectrometry (ICP-AES). The metals showed a similar order of concentration: Al > Fe > Ba > Mn > V > Ni > Pb > Cr > Zn > Cu, in both the Ceará; and Rio Grande do Norte shelf regions but different in the Espírito Santo shelf (Fe > Al > Mn > Ba > Zn > V > Cr > Ni > Pb > Cu. The concentrations of Hg and Cd were below the detection limit in all areas. A multivariate analysis revealed that the metals of siliciclastic origin on the continental shelf of Ceará are carried by Al. In addition, a large portion of metal deposits is connected to the iron and manganese oxides on the continental margin of Rio Grande do Norte. The metals from the continental supply on the coast of Espírito Santo (Cu, Ni, Ba, and Mn) are associated with Al; whereas Cr, Pb, V, and Zn are associated with iron in this southern area. Geochemical evaluations are needed to distinguish the origin and mineralogical differences of marine sediments within the regions. Scanning electron microscopy/energy dispersive spectrometry (SEM/EDS) applied to the sediments from the coast of Ceará showed the morphological diversity of sediment grains: biological fragments, multifaceted particles, aggregates, and crystals occurred in the three regions analyzed. Among these grains, calcite, Mg-calcite, and aragonite were predominant in the northeastern sector, whereas silicates and other minerals were predominant the southeastern sector. Mg, K, Ti, and Zr as well as the

  12. Solid/liquid partition coefficients (Kd) and plant/soil concentration ratios (CR) for selected soils, tills and sediments at Forsmark

    Solid/liquid partition coefficients (Kd) are used to indicate the relative mobility of radionuclides and elements of concern from nuclear fuel waste, as well as from other sources. To indicate the uptake of radionuclides in biota concentration ratios (CR) between soil and biota are used. This report summarized Kd data for regolith and marine sediments based on concentrations of 69 indigenous stable elements measured from samples collected at the Forsmark site and CR data concerning cereals growing on these soils. The samples included 50 regolith samples from agricultural land and wetlands, 8 samples of till collected at different depths, and two marine sediment samples. In addition, cereal grains, stems and roots were collected from 4 sites for calculation of CRs. The regolith samples represented the major 5 deposits, which can be used as arable land, at the site (clayey till, glacial clay, clay gyttja and peat (cultivated and undisturbed)). Kd values were generally lower for peat compared to clay soils. There were also clear differences in Kd resulting from differences in soil chemistry within each regolith type. Soil pH was the most important factor, and Kd values for many elements were lower in acidic clay soils compared to basic clay soils. Although there were only a few samples of sandy till and marine sediment, the Kd values were generally consistent with the corresponding regolith Kd values. Of the different cereal parts the grain always had the lowest CR. In most cases, the root CR was significantly higher than the grain CR, whereas only for a few elements were the grain and stem CR values different

  13. Solid/liquid partition coefficients (K{sub d}) and plant/soil concentration ratios (CR) for selected soils, tills and sediments at Forsmark

    Sheppard, Steve (ECOMatters Inc. (Canada)); Sohlenius, Gustav (Sveriges geologiska undersoekning (Sweden)); Omberg, Lars-Gunnar (ALS Scandinavia AB (Sweden)); Borgiel, Mikael (Sveriges Vattenekologer AB (Sweden)); Grolander, Sara (Facilia AB (Sweden)); Norden, Sara (Svensk Kaernbraenslehantering AB (Sweden))

    2011-11-15

    Solid/liquid partition coefficients (K{sub d}) are used to indicate the relative mobility of radionuclides and elements of concern from nuclear fuel waste, as well as from other sources. To indicate the uptake of radionuclides in biota concentration ratios (CR) between soil and biota are used. This report summarized K{sub d} data for regolith and marine sediments based on concentrations of 69 indigenous stable elements measured from samples collected at the Forsmark site and CR data concerning cereals growing on these soils. The samples included 50 regolith samples from agricultural land and wetlands, 8 samples of till collected at different depths, and two marine sediment samples. In addition, cereal grains, stems and roots were collected from 4 sites for calculation of CRs. The regolith samples represented the major 5 deposits, which can be used as arable land, at the site (clayey till, glacial clay, clay gyttja and peat (cultivated and undisturbed)). K{sub d} values were generally lower for peat compared to clay soils. There were also clear differences in K{sub d} resulting from differences in soil chemistry within each regolith type. Soil pH was the most important factor, and K{sub d} values for many elements were lower in acidic clay soils compared to basic clay soils. Although there were only a few samples of sandy till and marine sediment, the K{sub d} values were generally consistent with the corresponding regolith K{sub d} values. Of the different cereal parts the grain always had the lowest CR. In most cases, the root CR was significantly higher than the grain CR, whereas only for a few elements were the grain and stem CR values different

  14. Assessment of the governance system for the management of the East Sea-Jung dumping site, Korea through analysis of heavy metal concentrations in bottom sediments

    Song, Ki-Hoon; Choi, Ki-Young; Kim, Chang-Joon; Kim, Young-Il; Chung, Chang-Soo

    2015-12-01

    As with many countries, the Korea government has made a variety of efforts to meet the precautionary principle under the London Convention and Protocol acceded in 1994 and 2009. However, new strategies for the suitable marine dumping of waste materials have since been developed. In this study, the distribution and contamination of heavy metals including Al, Fe, Mn, Li, Co, Cr, Ni, Cu, Zn, As, Cd, Pb and Hg in bottom sediments were analyzed and compared to various criteria in order to evaluate the effectiveness of the management of the East Sea-Jung (ES-Jung) dumping site by the Korea government. The results indicate that the average metal concentrations were significantly lower than Effects Range Low (ERL) values, and generally similar to or lower than the Threshold Effect Levels (TEL) from the Sediment Quality Guidelinces (SQGs). According to analyses of various metal contamination indexes (Enrichment Factor: EF, Pollution Load Index: PLI and the Index of Geoaccumulation: Igeo), most areas were found to be uncontaminated by heavy metals with the exception of several moderately contaminated stations (ESJ 33, 54, 64 and ESJR 20). Heavy metal concentrations in areas grouped as G1, G2, DMDA, N-Ref and S-Ref which showed similar characteristics between 2007-2013 and 2014, were compared. Unexpectedly, most concentrations in the northern reference area (N-Ref) were much higher than those in the actual dumping areas (G1 and G2), may be due to the influences from nearby cities to the west of the ES-Jung site, rather than from the dumping site itself. Additionally, heavy metal concentrations in the dredged material dumping area (DMDA) were found to be low although they have slightly increased over time and those in the southern reference area (S-Ref) were found to have gradually decreased with year. The concentrations of most metals in the East Sea-Jung dumping site were similar to or less than those in the Earth's crust and approximately the same as those in continental

  15. 杭州湾湾口水体含沙量的时空分布%Spaciai-temporai distribution of suspended sediment concentration in Hangzhou Bay

    吴明阳; 许家帅; 冯玉林

    2011-01-01

    利用卫星遥感资料,结合现场实测数据,研究杭州湾湾口水体含沙量的时空分布,综合分析得出:杭州湾水体含沙量具有冬大夏小、高浓度悬沙广泛分布的特性,岛屿效应引起的局部高含沙是杭州湾岛屿群的共性.%Based on the information from the satelite remote sensing image and the measured SSC data from the field stations, this paper studies the spacial-temporal distribution of the sediment concentration in the Hangzhou Bay. The SSC of the Hangzhou Bay is high in winter and low in summer and the high SSC distributes extensively in the bay. It is common in the Hangzhou Bay that the locally high sediment concentration is caused by the archipelago effect.

  16. Evaluation of the activity concentration of {sup 226}Ra, {sup 228}Ra and {sup 210}Pb in sediments from Antarctica in the Admiralty Bay region

    Mora, Tamires de A.; Oliveira, Joselene de, E-mail: tamires.mora@usp.br, E-mail: jolivei@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Figueira, Rubens C.L.; Mahiques, Michel M.; Sousa, Silvia H.M., E-mail: rfigueira@usp.br, E-mail: mahiques@usp.br, E-mail: smsousa@usp.br [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Instituto Oceanografico

    2015-07-01

    In this study, we performed the radiochemical characterization of a sedimentary record (1B profile), collected in the vicinity of Admiralty Bay, King George Island in Antarctic Operation XXXI (January/2013). The activities of {sup 226}Ra, {sup 228}Ra and {sup 210}Pb were determined by the counting of gross alpha and gross beta activities in the precipitates of Ba(Ra)SO{sub 4} and PbCrO{sub 4}. Those measurements were carried out in a low background gas flow proportional detector. The {sup 226}Ra and {sup 228}Ra were measured after 21 days of the final precipitation. The {sup 210}Pb activity was determined after 10 days of the precipitation date by gross beta counting of its {sup 210}Bi decay product. The activity concentration of {sup 226}Ra ranged from 11±1 (mBq g-1) to 54±3 (mBq g{sup -1}), and the {sup 228}Ra ranged from 48±5 (mBq g{sup -1}) to 155±16 (mBq g{sup -1}). The activity concentration of {sup 210}Pb varied from 8±1 (mBq g{sup -1}) to 458±46 (mBq g{sup -1}), while unsupported {sup 210}Pb ranged from 6±1 (mBq g{sup -1}) to 434±65 (mBq g{sup -1}). The {sup 210}Pb concentrations in sediments have often been used to dating events like deposition and accumulation in various marine environments. Taking into account the results of {sup 210}Pb and {sup 226}Ra activities obtained in testimony-1B it was estimated the unsupported {sup 210}Pb activity which was applied to the CIC geochronological dating model (Constant Initial Concentration). Based in these data, the sedimentation rate obtained was 0.63±0.02 cm year{sup -1}. (author)

  17. Element concentrations in water spinach (Ipomoea aquatica Forssk.), fish and sediment from a wetland production system that receives wastewater from Phnom Penh, Cambodia.

    Marcussen, Helle; Dalsgaard, Anders; Holm, Peter E

    2009-01-01

    The Cheung Ek Lake, which is located south of Phnom Penh, Cambodia, receives most of the industrial and domestic wastewater that is produced in the city. The lake is used for fishing and production of water spinach (Ipomoea aquatica Forssk). Concentrations of 35 elements were determined in water spinach and sediment that were collected along transects of two wastewater inlets in the lake, at the lake outlet, and in a non-wastewater exposed pond. Elevated concentrations of the potentially toxic elements (PTEs) Cd, Cu, Ni, Pb, Sb, and Zn were found in the water spinach and sediment samples collected near the wastewater inlets. The highest determined PTE concentrations in water spinach were, in mg kg(- 1) fresh weight (f.w.), As 0.19, Cd 0.022, Cu 2.95, Fe 251, Pb 0.206 and Zn 9.08. For an adult person in Phnom Penh, the maximum intake of PTEs from consumption of water spinach harvested near the wastewater inlets amounts to 5.7% As, 1.4% Cd, 0.4% Cu, 20.5% Fe, 3.8% Pb and 0.6% Zn of the maximum tolerable intake set by the Codex Alimentarious Commission. Arsenic, Cd and Pb concentrations in the liver, skin, and muscle of three fish species caught in the lake were below or near the detection limits, except for a high accumulation of the three elements in the skin of the blackskin catfish. In conclusion, the consumption of water spinach and fish from Cheung Ek Lake constitutes a low food safety risk with respect to PTEs. PMID:19085597

  18. Concentrations of heavy metals in river sediments of the Canes River Basin, the state of Rio de Janeiro, Brazil

    Research about chimism in the Bengalas river basin was performed as a part of the environmental study project developed in the area, encompassing several knowledge fields. Among these, Environmental Geochemistry played an important role. This work presents the results related to heavy metals in stream sediments, indicating its origins (natural or anthropic) and its availability for aquatic biota. The basin under study has 135.07 Km2, laying in the oriental portion of the Teresópolis country, 100 Km far from the of Rio de Janeiro city. The rivers forming the Bengalas basin cut Pre-Cambrian terrain, formed by Orthognaiss takes 70% of the area, post-tectonic granite(20%), migmatite gneiss (10%) and gabro dikes. The methodology used was the determination of the content of heavy metals through sequencial extraction technique, consisting in the selective remove of metals in the geochemical fractions found in the sediments, cation exchange (bioavailable), carbonaceous, reducible and organic (potentially bioavailable) and residual (non available).The analyze of the results showed that iron was present in all sequential phases and predominated in the residual phase The same behavior was verified for zinc and copper. Manganese had the best distribution through the fractions due to its redox character, allowing bigger solubility and transportation; it appeared in the exchange, residual, organic and carbonaceous phases. Cadmium was found only in the carbonaceous phase, confirming its geochemical tendency. Chrome, on the other hand, was present in the residual and organic phase, while lead was found in the residual and carbonaceous phase

  19. Transport Model of Underground Sediment in Soils

    Sun Jichao; Wang Guangqian

    2013-01-01

    Studies about sediment erosion were mainly concentrated on the river channel sediment, the terrestrial sediment, and the underground sediment. The transport process of underground sediment is studied in the paper. The concept of the flush potential sediment is founded. The transport equation with stable saturated seepage is set up, and the relations between the flush potential sediment and water sediment are discussed. Flushing of underground sediment begins with small particles, and large pa...

  20. Adaptation and tolerance of bacteria against acetic acid.

    Trček, Janja; Mira, Nuno Pereira; Jarboe, Laura R

    2015-08-01

    Acetic acid is a weak organic acid exerting a toxic effect to most microorganisms at concentrations as low as 0.5 wt%. This toxic effect results mostly from acetic acid dissociation inside microbial cells, causing a decrease of intracellular pH and metabolic disturbance by the anion, among other deleterious effects. These microbial inhibition mechanisms enable acetic acid to be used as a preservative, although its usefulness is limited by the emergence of highly tolerant spoilage strains. Several biotechnological processes are also inhibited by the accumulation of acetic acid in the growth medium including production of bioethanol from lignocellulosics, wine making, and microbe-based production of acetic acid itself. To design better preservation strategies based on acetic acid and to improve the robustness of industrial biotechnological processes limited by this acid's toxicity, it is essential to deepen the understanding of the underlying toxicity mechanisms. In this sense, adaptive responses that improve tolerance to acetic acid have been well studied in Escherichia coli and Saccharomyces cerevisiae. Strains highly tolerant to acetic acid, either isolated from natural environments or specifically engineered for this effect, represent a unique reservoir of information that could increase our understanding of acetic acid tolerance and contribute to the design of additional tolerance mechanisms. In this article, the mechanisms underlying the acetic acid tolerance exhibited by several bacterial strains are reviewed, with emphasis on the knowledge gathered in acetic acid bacteria and E. coli. A comparison of how these bacterial adaptive responses to acetic acid stress fit to those described in the yeast Saccharomyces cerevisiae is also performed. A systematic comparison of the similarities and dissimilarities of the ways by which different microbial systems surpass the deleterious effects of acetic acid toxicity has not been performed so far, although such exchange

  1. Adamantane-1-ammonium acetate

    Elise J. C. de Vries

    2011-06-01

    Full Text Available In the title compound, C10H18N+·C2H3O2−, the ammonium H atoms of the cation are linked to three acetate anions via N—H...O hydrogen bonds, forming a chain structure extending along the b axis.

  2. Formation of asymmetric cellulose acetate membranes

    Bokhorst, H.; Altena, F.W.; Smolders, C.A.

    1981-01-01

    Cellulose acetate membranes were prepared from casting solutions containing dioxane as a solvent and varying concentrations (up to 6%) of maleic acid as an additive. Coagulation took place in water at different temperatures. The effect of these variables on membrane structure and membrane properties

  3. Concentration of polybrominated diphenyl ethers (PBDEs) in sediment cores of Sundarban mangrove wetland, northeastern part of Bay of Bengal (India)

    The paper presents the first comprehensive survey of congener profiles (12 congeners) of polybrominated diphenyl ethers (PBDEs) in core sediment samples (12 PBDE values ranging from 0.08 to 29.03 ng g-1, reflecting moderate to low contamination closely in conformity to other Asian aquatic environments. The general order of decreasing congener contribution to the total load was: BDE 47 > 99 > 100 > 154, similar to the distribution pattern worldwide. Although tetrabromodiphenyl ether BDE 47 was found in all samples followed by hexabromodiphenyl ether BDE-154, they were not necessarily the dominant congeners. No uniform temporal trend on PBDE levels was recorded probably due to particular hydrological characteristics of the wetland and/on non-homologous inputs from point sources (untreated municipal wastewater and local industries, electronic wastes from the dump sites, etc.) of these compounds. Because of the propensity of PBDEs to accumulate in various compartments of wildlife and human food webs, evaluation of biological tissues should be undertaken as a high priority

  4. Concentration of polybrominated diphenyl ethers (PBDEs) in sediment cores of Sundarban mangrove wetland, northeastern part of Bay of Bengal (India)

    Binelli, Andrea [Department of Biology, University of Milan, Via Celoria 26, 20133 Milan (Italy)]. E-mail: andrea.binelli@unimi.it; Sarkar, Santosh Kumar [Department of Marine Science, University of Calcutta, 35 Ballygunge Circular Road, Calcutta 700 019 (India); Chatterjee, Mousumi [Department of Marine Science, University of Calcutta, 35 Ballygunge Circular Road, Calcutta 700 019 (India); Riva, Consuelo [Department of Biology, University of Milan, Via Celoria 26, 20133 Milan (Italy); Parolini, Marco [Department of Biology, University of Milan, Via Celoria 26, 20133 Milan (Italy); Bhattacharya, Bhaskar deb [Department of Marine Science, University of Calcutta, 35 Ballygunge Circular Road, Calcutta 700 019 (India); Bhattacharya, Asok Kumar [Department of Marine Science, University of Calcutta, 35 Ballygunge Circular Road, Calcutta 700 019 (India); Satpathy, Kamala Kanta [Indira Gandhi Center for Atomic Research, Environmental and Industrial Safety Section, Safety Group, Kalpakkam 603 102, Tamil Nadu (India)

    2007-08-15

    The paper presents the first comprehensive survey of congener profiles (12 congeners) of polybrominated diphenyl ethers (PBDEs) in core sediment samples (<63 {mu}m) covering seven sites in Sundarban mangrove wetland (India). Gas-chromatographic analyses were carried out in GC-Ms/Ms for tri- to hepta- brominated congeners. Results pointed out a non-homogenous contamination of the wetland with {sigma}{sub 12} PBDE values ranging from 0.08 to 29.03 ng g{sup -1}, reflecting moderate to low contamination closely in conformity to other Asian aquatic environments. The general order of decreasing congener contribution to the total load was: BDE 47 > 99 > 100 > 154, similar to the distribution pattern worldwide. Although tetrabromodiphenyl ether BDE 47 was found in all samples followed by hexabromodiphenyl ether BDE-154, they were not necessarily the dominant congeners. No uniform temporal trend on PBDE levels was recorded probably due to particular hydrological characteristics of the wetland and/on non-homologous inputs from point sources (untreated municipal wastewater and local industries, electronic wastes from the dump sites, etc.) of these compounds. Because of the propensity of PBDEs to accumulate in various compartments of wildlife and human food webs, evaluation of biological tissues should be undertaken as a high priority.

  5. Heavy metal accumulation in Diplodus annularis, Liza aurata, and Solea vulgaris relevant to their concentration in water and sediment from the southwestern Mediterranean (coast of Sfax).

    Ben Salem, Zohra; Ayadi, Habib

    2016-07-01

    The concentrations of heavy metals (Cd, Cu, Fe, Pb, Ni, and Zn) were measured in the liver, gills, and muscle of Solea vulgaris, Liza aurata, and Diplodus annularis, collected from the south coast of Sfax (Gabes Gulf, southwestern Mediterranean). The concentrations of heavy metals in water exhibited the following decreasing order (expressed in μg l(-1)): Fe > Ni > Zn > Cu > Pb > Cd whereas the trend is somewhat different in sediments (mg kg(-1) D.W.) Fe > Zn > Pb > Ni > Cu > Cd. The levels of heavy metals varied significantly among fish species and tissues. Heavy metal levels were found generally higher in the liver and gills than the muscle in all species. The liver was the target organ for Cd, Cu, Fe, Ni, and Zn accumulation. Nickel and lead, however, exhibited their highest concentrations in the gills. The three studied fishes showed a difference in metals accumulation decreasing in following order S. vulgaris > D. annularis > L. aurata. Solea vulgaris with the highest TFwater, TFsediment, and metal concentrations in tissues would be considered as a potential bio-indicator in the south coast of Sfax for the assessment of environmental pollution status. Comparative studies with Luza zone indicate considerable bioaccumulation of heavy metals (Pb and Zn) in the various tissues of fish samples of the south coast of Sfax. PMID:27040537

  6. Estimation of suspended sediment concentration based on bio-optical mechanism and HJ-1 image in Chaohu Lake

    2010-01-01

    Synchronization experiment was conducted in June,2009 to get Inherent Optical Properties(IOP) of water component in Chaohu Lake.Water bio-optical mechanism was studied combined with multispectral data of Environmental Satellite 1(CCD),and then inversion models of total suspended matter(TSM),inorganic suspended matter(ISM) and organic suspended matter(OSM) concentration were built.The data indicated that:the absorption ratio of suspended particulate matter and CDOM to total were almost no change from band 1 to band 2 with about 85% and 9%,respectively.The ratio of pure water to total increased from 0.4% to 5.6%.Water reflectance in these two bands were influenced by absorption of three kinds of components:algae particles absorption surpassed non-algal particles in band 3,and so played an important role in total absorption with about 35.7%;the proportion of pure water absorption and particles matter backscattering both were 99% in band 4,so these two components decided the main inherent optical properties in band 4.The models of TSM and ISM concentration inversion based on band combination(band 3 + band 4)/(band 1 + band 2) were built,while OSM concentration was estimated by band 4/(band 1 + band 2) index.Inversed by image data,RE of TSM concentration between modeled and measured was 33.4%,and RMSE was 18.68 mg/L.RE of ISM and OSM concentration were 39.9% and 35.2% respectively.The inversion was more accurate when satellite-ground data were just in the same day.At this situation,RE of ISM concentration dropped to 25.4%,and that of TSM and OSM reduced to 26.5% and 26.8% as well.

  7. Remote sensing observations and numerical studies of a super typhoon-induced suspended sediment concentration variation in the East China Sea

    Li, Yangdong; Li, Xiaofeng

    2016-08-01

    By integrating remote sensing observations and a numerical modeling technique, we studied the influences of super Typhoon Saomai on the suspended sediment concentration (SSC) in the Yangtze River estuary and its adjacent coastal areas in the East China Sea. First, three consecutive Moderate Resolution Imaging Spectroradiometer (MODIS) images acquired during the post-typhoon stage were used to estimate the SSC. Then, we implemented a hydrodynamic model, including a sediment transport module, based on Delft3D to simulate the sediment erosion, re-suspension, transport and deposition processes in the study area during the passage of Typhoon Saomai. The model-simulated water level was validated against the in situ station data to show the feasibility of the model. The simulated SSC results agree reasonably well with the satellite observations. Time series of the simulation results showed that the model revealed the whole SSC variations during this extreme weather event and made up for the scarcity of in-situ and satellite observations. SSC significantly increased during the passage of the typhoon and decreased gradually during the post-typhoon stage. Modeled results also reveal that the spring-neap tidal effect significantly controlled the distribution and variation of SSC in the shallower coastal water (typhoon-induced re-suspension is evident in most of the study area, especially in the coastal waters near the Yangtze River estuary and Hangzhou Bay during the passage of the typhoon. Finally, based on the simulation results, we discuss the dynamic mechanisms including turbulent energy, bed shear stress and vertical mixing that caused the SSC variation.

  8. A Semi-Analytic Model for Estimating Total Suspended Sediment Concentration in Turbid Coastal Waters of Northern Western Australia Using MODIS-Aqua 250 m Data

    Passang Dorji

    2016-06-01

    Full Text Available Knowledge of the concentration of total suspended sediment (TSS in coastal waters is of significance to marine environmental monitoring agencies to determine the turbidity of water that serve as a proxy to estimate the availability of light at depth for benthic habitats. TSS models applicable to data collected by satellite sensors can be used to determine TSS with reasonable accuracy and of adequate spatial and temporal resolution to be of use for coastal water quality monitoring. Thus, a study is presented here where we develop a semi-analytic sediment model (SASM applicable to any sensor with red and near infrared (NIR bands. The calibration and validation of the SASM using bootstrap and cross-validation methods showed that the SASM applied to Moderate Resolution Imaging Spectroradiometer (MODIS-Aqua band 1 data retrieved TSS with a root mean square error (RMSE and mean averaged relative error (MARE of 5.75 mg/L and 33.33% respectively. The application of the SASM over our study region using MODIS-Aqua band 1 data showed that the SASM can be used to monitor the on-going, post and pre-dredging activities and identify daily TSS anomalies that are caused by natural and anthropogenic processes in coastal waters of northern Western Australia.

  9. Sediment concentrations, loads, and particle-size distributions in the Red River of the North and selected tributaries near Fargo, North Dakota, during the 2011 spring high-flow event

    Galloway, Joel M.; Blanchard, Robert A.; Ellison, Christopher A.

    2011-01-01

    To provide accurate and reliable information on sediment near the Fargo-Moorhead metropolitan area, the U.S. Geological Survey in cooperation with the U.S. Army Corps of Engineers conducted a study in the spring (March-May) of 2010 and the spring of 2011 to examine sediment concentrations, loads, and particle-size distributions at nine selected sites in the Red River and its tributaries. Samples of suspended sediment, bed material, and bedload were collected at the nine sites at various time intervals during the high-flow events.

  10. Organotin and osmoregulation: quantifying the effects of environmental concentrations of sediment-associated tri-n-butyltin and triphenyltin on osmoregulatory processes in the European flounder Platichthys flesus (L)

    Hartl, Mark G.J.

    2000-01-01

    The disruption of physiological and morphological aspects of osmoregulatory processes in freshwater-adapted 0-group European flounders, Platichthys flesus (L.), caused by exposure to environmental concentrations (150 ng triorganotin g"1 dry weight sediment) of sediment-associated tri-o-butyltin chloride (TBTCl) and triphenyltin chloride (TPhTCl), was examined and quantified. Radiotracers were used to measure hydromineral fluxes, the water balance and passive sodium efflux of ch...

  11. Spatio-temporal variability of phytoplankton (Chlorophyll-a) in relation to salinity, suspended sediment concentration, and light intensity in a macrotidal estuary

    Azhikodan, Gubash; Yokoyama, Katsuhide

    2016-09-01

    The influences of environmental gradients on the spatio-temporal variability of phytoplankton (Chlorophyll-a) in the macrotidal Chikugo River Estuary were studied during a two-week period of September 2010. Vertical profiles of salinity, turbidity, and light intensity were measured at 18 stations separated by a 1-km interval. Water samples for the determination of suspended sediment concentration (SSC), concentration of Chlorophyll-a (Chl-a) and Pheophytin-a (Pheo-a) were collected from the surface layer at all stations. The estuarine water column was vertically well mixed with high SSC (100-2000 mg L-1) during spring tide and the photic depth (zp) was less than 0.2 m. The mixing depth (zm) was more than 10 times the photic depth for the major part of the estuary. The estuary gradually changed to partially mixed with decrease in SSC (≤400 mg L-1) during the intermediate tide. The estuary became stratified with low SSC (20-50 mg L-1) during neap tide and the zp reached 4 m. The zm was less than 0.5 times the zp for the whole estuary. Light attenuation was dominated by SSC and the zp varied according to semidiurnal and semilunar tidal cycle. The zp: zm ratio did not show any relationship with Chl-a in the Chikugo river estuary. This is because the Chl-a concentration reached maximum two to three days after the neap tide. The peak concentration of Chl-a was located near the low salinity region and that of Pheo-a was located in the Estuarine Turbidity Maximum (ETM) zone. The Pheo-a concentration reached maximum during the spring tide. A good relation between zp: zm ratio and Pheo-a indicates that the increase in Pheo-a was caused by the light limitation due to suspended sediment and the responses of the Pheo-a on the light condition was instantaneous. These phenomena were remarkably found in the interface between freshwater and saltwater. Light availability driven by mixing and ETM process during semidiurnal and semilunar tidal cycle is the controlling factor of the

  12. Discharge and sediment concentration in the Bill Williams River and turbidity in Lake Havasu during and following high releases from Alamo Dam, Arizona, in March and April 2010

    Wiele, Stephen M.; Macy, Jamie P.; Darling, Hugh L.; Hart, Robert J.; Hautzinger, Andrew B.

    2011-01-01

    Discharges higher than are typically released from Alamo Dam in west-central Arizona were planned and released in 2005, 2006, 2007, 2008 and 2010 to study the effects of these releases on the Bill Williams River. The Bill Williams River Wildlife Refuge is located above the mouth of the Bill Williams River on Lake Havasu, and the river is the subject of ongoing ecological studies. Sediment concentrations and water discharges were measured in the Bill Williams River and turbidity, water temperature, specific conductance, pH, dissolved oxygen, and Secchi depth were measured in Lake Havasu during and after experimental releases in 2005 and 2006 from Alamo Dam. Additional measurements of the same parameters in the Bill Williams River and Lake Havasu were made during releases in 2010, and these are the subject of this report.

  13. Acetate transport across the intestinal epithelium of an herbivorous teleost

    3H-acetate transport across the upper intestine of the tilapia, Oreochromis mossabicus, using brush border and basolateral membrane vesicles, and intestinal sheets mounted in modified Ussing chambers was investigated. Brush border and basolateral vesicles demonstrated qualitatively similar anion antiport activity where, in the presence of a full profile of organic and inorganic anions, volatile fatty acids (VFA; acetate, propionate, butyrate) and bicarbonate showed reciprocal trans-stimulation and cis-inhibition of 3H-acetate influx, suggesting both membranes had the same VFA/bicarbonate exchange mechanism. Kinetic analysis of 3H-acetate influx into brush border and basolateral vesicles revealed different half-saturation constants (Km) as a function of external acetate concentrations (6.43 mM and 11.91 mM, respectively) and as a function of internal bicarbonate (5.89 mM and 0.41 mM, respectively). Intestinal sheets supported net absorptive fluxes when serosal acetate concentrations were held steady at 1.0 mM and mucosal acetate was varied from 1.60 to 10.0 mM. Unidirectional fluxes were significantly diminished by the addition of acetazolamide. This study postulates a transcellular transport pathway for VFA whereby qualitatively similar antiporters in series lead to a downhill flow of luminal acetate to the blood, which is driven by intracellular carbonic anhydrase and a transmural VFA concentration gradient

  14. Geochemical Fractionation of Copper (Cu, Lead (Pb, and Zinc (Zn in Sediment and their Correlations with Concentrations in Bivalve Mollusc Anadara indica from Coastal Area of Banten Province, Indonesia

    Noverita Dian Takarina

    2013-06-01

    Full Text Available Surface sediments collected from four sampling stations, each from the coastal area of Tanjung Pasir, Tangerang, and coastal areas of Panimbang, Pandeglang, Banten Province have been geochemically [easily, freely, leachable or exchangeable (EFLE, acid-reducible/Fe-Mn Oxides, oxidisable-organic and resistant] analyzed using AAS Shimadzu 6300 series. Cu, Pb, and Zn content in sediment fraction were correlated with the respective metal concentrations in tissues of Anadara indica collected from the same stations as for those sediment samples. The objective of this study was to determine the concentrations of heavy metals Cu, Pb and Zn in sediments and A. indica as well as to relate the possible differences in the accumulation patterns of Cu, Pb and Zn in A. indica to those in the geochemical fractions in the surface sediment. The results revealed that heavy metal concentrations were recorded to be higher in stations closed to the industries and anthropogenic activities (Garapan rivermouth, Tanjung Pasir compared to agricultural activities (Cibungur rivermouth, Panimbang. Significant (p < 0.01 correlations were observed between Cu in the soft tissue of A. indica with exchangeable, Fe-Mn oxides, oxidisable organic, residual fractions of Cu in the sediment, and Fe-Mn oxides, oxidisable organic, residual fraction for Pb, while significant correlations were observed between Zn in soft tissue of A. indica with Fe-Mn oxides and oxidisable organic fractions. It is suggested that the soft tissue of A. indica could be used as a useful biomonitoring agent for Cu, Pb, and Zn pollution.

  15. Sea to land transfer of anthropogenic radionuclides to the North Wales coast, Part I: External gamma radiation and radionuclide concentrations in intertidal sediments, soil and air

    Previous projects specifically aimed at performing radiological assessments in the vicinity of North Wales, investigating the presence and transfer of radionuclides from sea to land, were in 1986 and 1989. Since then, changes have occurred in the radioactive discharges from the British Nuclear Group Sellafield site. Annual discharges of 137Cs, 238Pu, 239,340Pu and 241Am have decreased markedly whereas, up until recent years, discharges of 99Tc have increased. It is therefore desirable to quantify current transfer processes of radionuclides in the North Wales region and thus provide an update on 15-year-old studies. A field campaign was conducted collecting soil samples from 10 inland transects and air particulates on air filters from three High Volume Air Samplers, along the northern coast of Wales at Amlwch, Bangor Pier and Flint. Complementary field data relating to external gamma dose rates were collected at the soil sites. The field data generated for 137Cs, 238Pu, 239,340Pu and 241Am were consistent with what had been reported 15 years previously. Therefore, there has been no increase in the supply of these Sellafield-derived radionuclides to the terrestrial environment of the North Wales coast. The 99Tc data in sediments were consistent with reported values within annual monitoring programmes, however, a relatively high activity concentration was measured in one sediment sample. This site was further investigated to determine the reason why such a high value was found. At present there is no clear evidence as to why this elevated concentration should be present, but the role of seaweed and its capacity in accumulating 99Tc and transferring it to sediment is of interest. The analysis of the field samples for 99Tc, 137Cs, 238Pu, 239,240Pu and 241Am has provided a data set that can be used for the modelling of the transfer of anthropogenic radionuclides from sea to land and its subsequent radiological implications and is reported in an accompanying paper

  16. Element composition of biota, water and sediment in the Forsmark area, Baltic Sea. Concentrations, bioconcentration factors and partitioning coefficients (K{sub d}) of 48 elements

    Kumblad, Linda; Bradshaw, Clare (Dept. of Systems Ecology, Stockholm Univ. (Sweden))

    2008-08-15

    In this study the elemental composition of biota, water and sediment from a shallow bay in the Forsmark region have been determined. The report presents data for 48 different elements (Al, As, Ba, Br, C, Ca, Cd, Ce, Cl, Co, Cr, Cs, Cu, Dy, Er, Eu, F, Fe, Gd, Hg, Ho, I, K, Li, Lu, Mg, Mn, N, Na, Nd, Ni, P, Pb, Pr, Ra, Rb, S, Se, Si, Sm, Tb, Th, Ti, Tm, V, Yb, Zn, Zr) in all major functional groups of the coastal ecosystem (phytoplankton, zooplankton, benthic microalgae, macroalgae, macrophytes, benthic herbivores, benthic filter feeders, benthic detrivores, planktivorous fish, benthic omnivorous fish, carnivorous fish, dissolved and particulate matter in the water and the sediment) during spring 2005. The overall aim of the study is to contribute to a better understanding of ecological properties and processes that govern uptake and transfer of trace elements, heavy-metals, radionuclides and other non-essential elements/contaminants in coastal environments of the Baltic Sea. In addition, the data was collected to provide site-specific Bioconcentration Factors (BCF), Biomagnification Factors (BMF), partitioning coefficients (K{sub d}) and element ratios (relative to carbon) for use in ongoing SKB safety assessments. All these values, as well as the element concentration data from which they are derived, are presented here. As such, this is mainly a data report, although initial interpretations of the data also are presented and discussed. Reported data include element concentrations, CNP-stoichiometry, and multivariate data analysis. Elemental concentrations varied greatly between organisms and environmental components, depending on the function of the elements, and the habitat, ecosystem function, trophic level and morphology (taxonomy) of the organisms. The results show for instance that food intake and metabolism strongly influence the elemental composition of organisms. The three macrophytes had quite similar elemental composition (despite their taxonomic

  17. Element composition of biota, water and sediment in the Forsmark area, Baltic Sea. Concentrations, bioconcentration factors and partitioning coefficients (Kd) of 48 elements

    In this study the elemental composition of biota, water and sediment from a shallow bay in the Forsmark region have been determined. The report presents data for 48 different elements (Al, As, Ba, Br, C, Ca, Cd, Ce, Cl, Co, Cr, Cs, Cu, Dy, Er, Eu, F, Fe, Gd, Hg, Ho, I, K, Li, Lu, Mg, Mn, N, Na, Nd, Ni, P, Pb, Pr, Ra, Rb, S, Se, Si, Sm, Tb, Th, Ti, Tm, V, Yb, Zn, Zr) in all major functional groups of the coastal ecosystem (phytoplankton, zooplankton, benthic microalgae, macroalgae, macrophytes, benthic herbivores, benthic filter feeders, benthic detrivores, planktivorous fish, benthic omnivorous fish, carnivorous fish, dissolved and particulate matter in the water and the sediment) during spring 2005. The overall aim of the study is to contribute to a better understanding of ecological properties and processes that govern uptake and transfer of trace elements, heavy-metals, radionuclides and other non-essential elements/contaminants in coastal environments of the Baltic Sea. In addition, the data was collected to provide site-specific Bioconcentration Factors (BCF), Biomagnification Factors (BMF), partitioning coefficients (Kd) and element ratios (relative to carbon) for use in ongoing SKB safety assessments. All these values, as well as the element concentration data from which they are derived, are presented here. As such, this is mainly a data report, although initial interpretations of the data also are presented and discussed. Reported data include element concentrations, CNP-stoichiometry, and multivariate data analysis. Elemental concentrations varied greatly between organisms and environmental components, depending on the function of the elements, and the habitat, ecosystem function, trophic level and morphology (taxonomy) of the organisms. The results show for instance that food intake and metabolism strongly influence the elemental composition of organisms. The three macrophytes had quite similar elemental composition (despite their taxonomic differences

  18. Concentration of Beryllium (Be) and Depleted Uranium (DU) in Marine Fauna and Sediment Samples from Illeginni and Boggerik Islands at Kwajalein Atoll

    Robison, W L; Hamilton, T F; Martinelli, R E; Kehl, S R; Lindman, T R

    2005-02-24

    Lawrence Livermore National Laboratory (LLNL) personnel have supported US Air Force (USAF) ballistic missile flight tests for about 15 years for Peacekeeper and Minuteman missiles launched at Vandenberg Air Force Base (VAFB). Associated re-entry vehicles (RV's) re-enter at Regan Test Site (RTS) at the US Army base at Kwajalein Atoll (USAKA) where LLNL has supported scoring, recovery operations for RV materials, and environmental assessments. As part of ongoing USAF ballistic missile flight test programs, LLNL is participating in an updated EA being written for flights originating at VFAB. Marine fauna and sediments (beach-sand samples) were collected by US Fish and Wildlife Service (USFWS), National Marine Fisheries Service (NMFS), and LLNL at Illeginni Island and Boggerik Island (serving as a control site) at Kwajalein Atoll. Data on the concentration of DU (hereafter, U) and Be in collected samples was requested by USFWS and NMFS to determine whether or not U and Be in RV's entering the Illeginni area are increasing U and Be concentrations in marine fauna and sediments. LLNL agreed to do the analyses for U and Be in support of the EA process and provide a report of the results. There is no statistically significant difference in the concentration of U and Be in six species of marine fauna from Illeginni and Boggerik Islands (p - 0.14 for U and p = 0.34 for Be). Thus, there is no evidence that there has been any increase in U and Be concentrations in marine fauna as a result of the missile flight test program. Concentration of U in beach sand at Illeginni is the same as soil and beach sand in the rest of the Marshall Islands and again reflects an insignificant impact from the flight test program. Beach sand from Illeginni has a mean concentration of Be higher than that from the control site, Boggeik Island. Seven of 21 samples from Ileginni had detectable Be. Four samples had a concentration of Be ranging from 4 to 7 ng g {sup -1} (4 to 7 parts per

  19. 4-Carbamoylpiperidinium acetate monohydrate

    Urs D. Wermuth

    2010-12-01

    Full Text Available In the structure of the title compound, C6H13N2O+·C2H3O2−·H2O, the amide H atoms of the cations form centrosymmetric cyclic hydrogen-bonding associations incorporating two water molecules [graph set R42(8], which are conjoint with cyclic water-bridged amide–amide associations [R44(12] and larger R44(20 associations involving the water molecule and the acetate anions, which bridge through the piperidinium H-bond donors, giving an overall three-dimensional framework structure.

  20. Uranium hydrogeochemical and stream sediment reconnaissance data listing release for the Three Forks Basin, Spanish Peaks, and Boulder River areas for the Bozeman NTMS quadrangle, Montana, including concentrations of forty-six additional elements

    Totals of 531 water and 1275 sediment samples were collected from 1275 stream and spring locations. Elemental concentration, field measurement, weather, geologic, and geographic data for each sample location are listed for waters and for sediments. Uranium/thorium ratios for sediment samples are also included. Water samples were initially analyzed for uranium by fluorometry. All water samples containing more than 40 ppB uranium were reanalyzed by delayed-neutron counting (DNC). All sediments were analyzed for uranium by DNC. Other elemental concentrations in sediments were determined by neutron activation analysis for 31 elements (Al, Sb, Ba, Ca, Ce, Cs, Cl, Cr, Co, Dy, Eu, Au, Hf, Fe, La, Lu, Mg, Mn, K, Rb, Sn, Sc, Na, Sr, Ta, Tb, Th, Ti, V, Yb, and Zn), by x-ray fluorescence for 13 elements (As, Bi, Cd, Cu, Pb, Mo, Ni, Nb, Se, Ag, Sn, W, and Zr), and by arc-source emission spectrography for Li and Be. Analytical results for sediments are reported as parts per million

  1. Water quality - Evaluation of the aerobic biodegradability of organic compounds at low concentrations. Part 1: Shake-flask batch test with surface water or suface water/sediment suspensions. ISO 14592-1

    Nyholm, Niels; Pagga, U.

    ISO 14592-1:2002 specifies a test method for evaluating the biodegradability of organic test compounds by aerobic microorganisms in surface waters by means of a shake-flask batch test with suspended biomass. It is applicable to natural surface water, free from coarse particles to simulate a pelagic...... environment (pelagic test) or to surface water with suspended solids or sediments added to obtain a level of 0,1 g/l to 1 g/l dry mass (suspended sediment test) to simulate a water-to-sediment interface or a water body with resuspended sediment material. ISO 14592-1:2002 is applicable to organic test......-growth kinetics). This test method is not recommended for use as proof of ultimate biodegradation which is better assessed using other standardized tests. It is also not applicable to studies on metabolite formation and accumulation which require higher test concentrations....

  2. Patterns of landscape evolution on the central and northern Tibetan Plateau investigated using in-situ produced 10Be concentrations from river sediments

    Li, Yingkui; Li, Dewen; Liu, Gengnian; Harbor, Jon; Caffee, Marc; Stroeven, Arjen P.

    2014-07-01

    Quantifying long-term erosion rates across the Tibetan Plateau and its bordering mountains is of critical importance to an understanding of the interaction between climate, tectonic movement, and landscape evolution. We present a new dataset of basin-wide erosion rates from the central and northern Tibetan Plateau derived using in-situ produced 10Be concentrations of river sediments. Basin-wide erosion rates from the central plateau range from 10.1±0.9 to 36.8±3.2 mm/kyr, slightly higher than published local erosion rates measured from bedrock surfaces. These values indicate that long-term downwearing of plateau surfaces proceeds at low rates and that the landscape is demonstrably stable in the central plateau. In contrast, basin-wide erosion rates from the Kunlun Shan on the northern Tibetan Plateau range from 19.9±1.7 to 163.2±15.9 mm/kyr. Although the erosion rates of many of these basins are much higher than the rates from the central plateau, they are lower than published basin-wide erosion rates from other mountains fringing the Tibetan Plateau, probably because the basins in the Kunlun Shan include both areas of low-relief plateau surface and high-relief mountain catchments and may also result from retarded fluvial sediment transport in an arid climate. Significantly higher basin-wide erosion rates derived from the Tibetan Plateau margin, compared to the central plateau, reflect a relatively stable plateau surface that is being dissected at its margins by active fluvial erosion.

  3. Effects of lead-contaminated sediment and nutrition on mallard duckling brain growth and biochemistry

    Day-old mallard (Anas platyryhnchos) ducklings received either a clean sediment (24%) supplemented control diet, Coeur d'Alene River Basin, Idaho (CDARB) sediment (3449 μg/g lead) supplemented diets at 12% or 24%, or a positive control diet (24% clean sediment with equivalent lead acetate to the 24% CDARB diet) for 6 weeks. The 12% CDARB diet resulted in a geometric mean concentration of 396 ppb (WW) brain lead with decreased brain protein and ATP concentrations but increased oxidized glutathione (GSSG) relative to the control diet. The 24% CDARB diet resulted in a concentration of 485 ppb brain lead with lower brain weight and ATP concentration than controls but higher concentrations of reduced glutathione (GSH) and calcium. Lead acetate accumulated twice as well as CDARB derived lead and resulted in histopathological lesions of the brain. With a combination of a suboptimal diet and 24% CDARB, brain lead concentration was higher (594 ppb) than with 24% CDARB in the standard diet, histopathological lesions became apparent and GSH was higher than suboptimal diet controls

  4. Effects of lead-contaminated sediment and nutrition on mallard duckling brain growth and biochemistry

    Douglas-Stroebel, E.; Hoffman, D.J.; Brewer, G.L.; Sileo, L.

    2004-01-01

    Day-old mallard (Anas platyryhnchos) ducklings received either a clean sediment (24%) supplemented control diet, Coeur d'Alene River Basin, Idaho (CDARB) sediment (3449 I?g/g lead) supplemented diets at 12% or 24%, or a positive control diet (24% clean sediment with equivalent lead acetate to the 24% CDARB diet) for 6 weeks. The 12% CDARB diet resulted in a geometric mean concentration of 396 ppb (WW) brain lead with decreased brain protein and ATP concentrations but increased oxidized glutathione (GSSG) relative to the control diet. The 24% CDARB diet resulted in a concentration of 485 ppb brain lead with lower brain weight and ATP concentration than controls but higher concentrations of reduced glutathione (GSH) and calcium. Lead acetate accumulated twice as well as CDARB derived lead and resulted in histopathological lesions of the brain. With a combination of a suboptimal diet and 24% CDARB, brain lead concentration was higher (594 ppb) than with 24% CDARB in the standard diet, histopathological lesions became apparent and GSH was higher than suboptimal diet controls.

  5. Assessment of metal concentrations in sediment samples from Billings Reservoir, Rio Grande tributary, Sao Paulo, Brazil; Avaliacao da concentracao de metais em amostras de sedimento do Reservatorio Billings, Braco Rio Grande, Sao Paulo, Brasil

    Bostelmann, Eleine

    2006-07-01

    The present study chemically characterized sediment samples from the Billings reservoir, Rio Grande tributary, in the Metropolitan region of Sao Paulo, by determining metal concentration and other elements of interest. The chosen chemical parameters for this characterization were Aluminum, Arsenic, Barium, Cadmium, Copper, Chromium, Iron, Lead, Manganese, Mercury, Nickel, Selenium and Zinco. These parameters are also used in the water quality index, with the exception of Selenium. The concentrations were determined through different analytical techniques such as atomic absorption spectrometry (FAAS, GFAAS and CVAAS), optical emission spectrometry (ICP OES) and neutron activation analysis. These analytical methodologies were assessed for precision, accuracy and detection and/or quantification limits for the sediment elements in question. Advantages and disadvantages of each technique for each element and its concentration were also discussed. From these assessments the most adequate technique was selected for the routine analysis of sediment samples for each element concentration determination. This assessment verified also that digestion in a closed microwave system with nitric acid is efficient for the evaluation of extracted metals of environmental interest. The analytical techniques chosen were equally efficient for metals determination. In the case of Cd and Pb, the FAAS technique was selected due to better results than ICP OES, as it does not present matrix interference. The concentration values obtained for metals As, Cd, Cu, Cr, Hg, Ni, Pb and Zn in the sediment samples were compared to Canadian Council of Minister of the Environment (CCME) TEL and PEL values. (author)

  6. Acetic Acid Production by an Electrodialysis Fermentation Method with a Computerized Control System

    Nomura, Yoshiyuki; Iwahara, Masayoshi; Hongo, Motoyoshi

    1988-01-01

    In acetic acid fermentation by Acetobacter aceti, the acetic acid produced inhibits the production of acetic acid by this microorganism. To alleviate this inhibitory effect, we developed an electrodialysis fermentation method such that acetic acid is continuously removed from the broth. The fermentation unit has a computerized system for the control of the pH and the concentration of ethanol in the fermentation broth. The electrodialysis fermentation system resulted in improved cell growth an...

  7. Dissolution of paracetamol crystallized in the presence of poly(vinyl acetate-co-maleic anhydride)

    Raval D; Parikh D; Patel V

    2006-01-01

    Copolymer of vinyl acetate and maleic anhydride, poly (vinyl acetate-co-maleic anhydride) was prepared by precipitation polymerization and characterized. Paracetamol was crystallized in presence of different concentrations of poly (vinyl acetate-co-maleic anhydride). Crystals were characterized by sieve analysis, solubility and dissolution study. Crystallization of paracetamol in presence of poly (vinyl acetate-co-maleic anhydride) caused a marked enhancement in its dissolution rate with incr...

  8. Biogas Production through the Syntrophic Acetate-Oxidising Pathway. Characterisation and Detection of Syntrophic Acetate- Oxidising Bacteria

    Westerholm, Maria [Faculty of Natural Resources and Agricultural Sciences, Dept. of Microbiology, Swedish Univ. of Agricultural Sciences, Uppsala (Sweden)

    2012-11-01

    Biogas produced from wastes, residues and energy crops has promising potential to reduce greenhouse gas emissions and to secure future energy supply. Methane is the energy-rich component of biogas, and is formed as the end product during degradation of organic material without oxygen (anaerobic). Acetate is an important intermediate in anaerobic degradation and can be converted to methane through two pathways: aceticlastic methanogenesis and syntrophic acetate oxidation (SAO). SAO is a two-step reaction, consisting of acetate oxidation to hydrogen and carbon dioxide by syntrophic acetate-oxidising bacteria (SAOB), followed by conversion of these products to methane by hydrogenotrophic methanogens. Ammonia and acetate concentration, hydraulic retention time, temperature and methanogenic population structure are operational parameters considered to influence the acetate conversion pathway. This thesis sought to increase understanding of SAO by examining syntrophic acetate oxidisers in pure culture, co-culture and methanogenic reactors. Two novel species of SAOB, Syntrophaceticus schinkii and Tepidanaerobacter acetatoxydans, were isolated and their phenotypic and phylogenetic traits were characterised. Quantitative molecular approaches were developed and applied to determine structural dynamics in the methane-producing population in a mesophilic biogas reactor during an ammonia-induced shift from aceticlastic to syntrophic acetate degradation. The abundance of SAOB increased, with a simultaneous decrease in aceticlastic methanogens. The majority of known SAOB are considered acetogens, and gradually increased ammonia concentration was shown to cause distinct shifts in the putative acetogenic population structure in mesophilic biogas reactors. However, the acetogenic bacterial abundance remained relatively stable. Bioaugmentation of syntrophic acetate-oxidising cultures did not improve process performance or support establishment of SAO as the dominant acetate

  9. Quantitative determination of microbial activity and community nutritional status in estuarine sediments: evidence for a disturbance artifact

    Findlay, R. H.; Pollard, P. C.; Moriarty, D. J.; White, D. C.

    1985-01-01

    In estuarine sediments with a high degree of vertical heterogeneity in reduced substrate and terminal electron acceptor concentrations, the method of exposure of the microbiota to labeled substrates can introduce a "disturbance artifact" into measures of metabolic activity. The detection of this artifact is based on quantitative measurement of the relative rates of incorporation of [14C]acetate into phospholipid fatty acids (PLFA) and endogenous storage lipid, poly-beta-hydroxyalkanoate (PHA). Previous studies have shown that PLFA synthesis measures cellular growth and that PHA synthesis measures carbon accumulation (unbalanced growth). The "disturbance artifact" of exposure to [14C]acetate was demonstrated by comparing injection of a core with the usual or pore-water replacement or slurry techniques. Only injection of labeled substrate allowed detection of preassay disturbance of the sediment with a garden rake. The raking increased PLFA synthesis with little effect to differences in concentration or distribution of [14C]acetate in the 10-min incubation. Bioturbation induced by sand dollar feeding in estuarine sediment could be detected in an increased PLFA/PHA ratio which was due to decreased PHA synthesis if the addition of labeled substrate was by the injection technique. Addition of labeled precursors to sediment by slurry or pore-water replacement induces greater disturbance artifacts than injection techniques.

  10. Comparison of the role of the sea club-rush Scirpus maritimus and the sea rush Juncus maritimus in terms of concentration, speciation and bioaccumulation of metals in the estuarine sediment.

    Almeida, C Marisa R; Mucha, Ana P; Vasconcelos, M Teresa S D

    2006-07-01

    The capability of Scirpus maritimus and of Juncus maritimus to accumulate metals and the role of each plant on the physico-chemical composition of sediments, from Douro river estuary (NW Portugal), were investigated through a year of plants' life. The contents of Al, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn were determined (by atomic absorption spectrophotometry) in sediment, rhizosediments (those in contact with each plant roots and rhizomes) and different tissues of S. maritimus and of J. maritimus. Both plants influenced the sediment composition (concentrating metals around its roots) and were able to bioaccumulate Cd, in spite of some seasonal variations in the metal levels in the system (both in rhizosediments and plants' roots). Therefore, both plants showed to have potential for Cd phytostabilization. S. maritimus could also concentrate Pb in its roots, probably by sorption on the root surface in (hydr)oxide forms, therefore, denoting capability for Pb phytostabilization. PMID:16278040

  11. Controls of channel morphology and sediment concentration on flow resistance in a large sand-bed river: A case study of the lower Yellow River

    Ma, Yuanxu; Huang, He Qing

    2016-07-01

    Accurate estimation of flow resistance is crucial for flood routing, flow discharge and velocity estimation, and engineering design. Various empirical and semiempirical flow resistance models have been developed during the past century; however, a universal flow resistance model for varying types of rivers has remained difficult to be achieved to date. In this study, hydrometric data sets from six stations in the lower Yellow River during 1958-1959 are used to calibrate three empirical flow resistance models (Eqs. (5)-(7)) and evaluate their predictability. A group of statistical measures have been used to evaluate the goodness of fit of these models, including root mean square error (RMSE), coefficient of determination (CD), the Nash coefficient (NA), mean relative error (MRE), mean symmetry error (MSE), percentage of data with a relative error ≤ 50% and 25% (P50, P25), and percentage of data with overestimated error (POE). Three model selection criterions are also employed to assess the model predictability: Akaike information criterion (AIC), Bayesian information criterion (BIC), and a modified model selection criterion (MSC). The results show that mean flow depth (d) and water surface slope (S) can only explain a small proportion of variance in flow resistance. When channel width (w) and suspended sediment concentration (SSC) are involved, the new model (7) achieves a better performance than the previous ones. The MRE of model (7) is generally < 20%, which is apparently better than that reported by previous studies. This model is validated using the data sets from the corresponding stations during 1965-1966, and the results show larger uncertainties than the calibrating model. This probably resulted from the temporal shift of dominant controls caused by channel change resulting from varying flow regime. With the advancements of earth observation techniques, information about channel width, mean flow depth, and suspended sediment concentration can be

  12. ACETIC ACID AND A BUFFER

    2009-01-01

    The present invention relates to a composition comprising : a) 0.01-20% wt/wt acetic acid and b) a physiologically tolerable buffer capable of maintaining acetic acid at a pH in the range of 2-7; and use of such a composition as an antimicrobial agent.......The present invention relates to a composition comprising : a) 0.01-20% wt/wt acetic acid and b) a physiologically tolerable buffer capable of maintaining acetic acid at a pH in the range of 2-7; and use of such a composition as an antimicrobial agent....

  13. A study of flow in alluvial channels: the effect of large concentrations of fine sediment on the mechanics of flow in a small flume

    Haushild, William Leland; Simons, Daryl Baldwin; Richadrson, Everett V.

    A flume study was made using a natural river sand as the bed material, median diameter = 0. 54 millimeters. Clear-water flow was compared with flow containing from 6 1 000 to 65,000 parts per million of fine sediment (bentonite). The study shows that the form of bed roughness could be changed by adding sufficient fine sediment (bentonite) to the clear-water flow. The total bed material transport was decreased by 50 percent with increasing fine sediment

  14. Application of acetate, lactate, and fumarate as electron donors in microbial fuel cell

    Vasyliv, Oresta M.; Bilyy, Oleksandr I.; Ferensovych, Yaroslav P.; Hnatush, Svitlana O.

    2013-09-01

    Microbial fuel cells (MFCs) are devices that use bacteria as the catalysts to oxidize organic and inorganic matter and generate current. Up to now, several classes of extracellular electron transfer mechanisms have been elucidated for various microorganisms. Shewanellaceae and Geobacteraceae families include the most of model exoelectrogenic microorganisms. Desulfuromonas acetoxidans bacterium inhabits aquatic sedimental sulfur-containing environments and is philogenetically close to representatives of Geobacteraceae family. Two chamber microbial fuel cell (0.3 l volume) was constructed with application of D. acetoxidans IMV B-7384 as anode biocatalyst. Acetic, lactic and fumaric acids were separately applied as organic electron donors for bacterial growth in constructed MFC. Bacterial cultivation in MFC was held during twenty days. Lactate oxidation caused electric power production with the highest value up to 0.071 mW on 64 hour of D. acetoxidans IMV B-7384 growth. Addition of acetic and fumaric acids into bacterial growth medium caused maximal power production up to 0.075 and 0.074 mW respectively on the 40 hour of their growth. Increasing of incubation time up to twentieth day caused decrease of generated electric power till 0.018 mW, 0.042 mW and 0.047 mW under usage of lactic, acetic and fumaric acids respectively by investigated bacteria. Power generation by D. acetoxidans IMV B-7384 was more stabile and durable under application of acetic and fumaric acids as electron donors in constructed MFC, than under addition of lactic acid in the same concentration into the growth medium.

  15. Relief evolution of the Continental Rift of Southeast Brazil revealed by in situ-produced 10Be concentrations in river-borne sediments

    Salgado, André Augusto Rodrigues; Rezende, Eric de Andrade; Bourlès, Didier; Braucher, Régis; da Silva, Juliana Rodrigues; Garcia, Ricardo Alexandrino

    2016-04-01

    This study aims to quantify the denudation dynamics of the Brazilian passive margin along a segment of the Continental Rift of Southeast Brazil. The denudation rates of 30 basins that drain both horsts of the continental rift, including the mountain ranges of the Serra do Mar (seaside horst); and the Serra da Mantiqueira (continental horst); were derived from 10Be concentrations measured in sand-sized river sediment. The mean denudation rate ranges from 9.2 m Ma-1 on the plateau of the Serra do Mar to 37.1 m Ma-1 along the oceanic escarpment of the Serra do Mar. The seaward-facing scarps of both mountain ranges exhibit mean denudation rates that are approximately 1.5 times those of the inland-facing scarps. The escarpments of the horst nearer to the ocean (Serra do Mar) exhibit higher denudation rates (mean 30.2 m Ma-1) than the escarpments of the continental horst (Serra da Mantiqueira) (mean 16.5 m Ma-1). The parameters that impact these denudation rates include the catchment relief, the slope gradient, the rock and the climate. The incongruent combination of a mountainous landscape and moderate to low 10Be-based denudation rates averaging at ∼20 m Ma-1 suggests a reduction in intraplate tectonic activity beginning in the Middle Quaternary or earlier.

  16. Inversion of suspended sediment concentration at the Hangzhou Bay based on the high-resolution satellite HJ-1A/B imagery

    Meng, Qinghui; Mao, Zhihua; Huang, Haiqing; Shen, Yuzhang

    2013-09-01

    HJ-1A/B were two small satellite constellations, that were launched for the environment and disaster monitoring and forecasting on September 6th, 2008. Based on the advantages of high temporal and spacial resolution of the HJ CCD data, this paper aims at evaluate four inversion algorithms of suspended sediments concentration by the remote sensing reflectance in the Hangzhou Bay. First, the atmospheric correction of HJ-1 A/B CCD imagery was carried out using fast line-of-sight atmospheric analysis of spectral hypercubes (FLAASH) model, in which aerosol optical depth was retrieved from synchronous Terra/MODIS data. Then, four classical band ratio algorithms were evaluated. Results show that He's GOCI model was better than others with 12.75% relative error. At last, we compare the discrepancy between He's GOCI algorithm and any other three model, results indicate that the other three empirical algorithms performance not very good because of the difference come from different satellite data, various study area, different research season, distinct correction result. This research has an important practical significance to improving the SSC inversion in the HZB.

  17. Filling of the Three Gorges Reservoir to the 135-m Level:Instant Effects on the Yangtze Discharge and Suspended Sediment Concentration Entering the Estuary

    CHU Zhongxin; ZHAI Shikui; ZHANG Jing; DING Dong

    2009-01-01

    Via the valuable opportunity of the Three Gorges Reservoir (TGR) 135-m filling in June 2003, the Yangtze discharge and suspended sediment concentration (SSC) entering the estuary during the period from 15 May to 15 July 2003 were analyzed to examine the instant effects of the filling on them. The Yangtze discharge and SSC entering the estuary in the periods before, during and after the filling clearly indicated three phases: 1) the pre-storage phase characterized by natural conditions, in which the SSC increased with increasing water discharge; 2) the storage phase, during which the SSC decreased dramatically with decreasing water discharge; and 3) the post-storage phase, during which both the SSC and water discharge remained at relatively low levels first until the end of June, then the SSC increased gradually with increasing water discharge. It seems that the times for the instant effects of the decreasing discharge downstream from the upper Yangtze on the Yangtze discharge and SSC entering the estuary due to the TGR 135-m filling to take place were about 5d and 1d respectively, while both were about 18d for those of the increasing discharge. This probably reflects the buffering and resultantly hysteresis of the 1800-km stretch from the upper Yangtze to the estuary. The results are helpful for scientific and hydrological investigation of the Yangtze mainstream downstream from the TGR Dam and of the estuarine and adjacent coastal waters.

  18. Response of reef corals on a fringing reef flat to elevated suspended-sediment concentrations: Molokaʻi, Hawaiʻi

    Paul L. Jokiel

    2014-12-01

    Full Text Available A long-term (10 month exposure experiment on effects of suspended sediment on the mortality, growth, and recruitment of the reef corals Montipora capitata and Porites compressa was conducted on the shallow reef flat off south Molokaʻi, Hawaiʻi. Corals were grown on wire platforms with attached coral recruitment tiles along a suspended solid concentration (SSC gradient that ranged from 37 mg l−1 (inshore to 3 mg l−1 (offshore. Natural coral reef development on the reef flat is limited to areas with SSCs less than 10 mg l−1 as previously suggested in the scientific literature. However, the experimental corals held at much higher levels of turbidity showed surprisingly good survivorship and growth. High SSCs encountered on the reef flat reduced coral recruitment by one to three orders of magnitude compared to other sites throughout Hawaiʻi. There was a significant correlation between the biomass of macroalgae attached to the wire growth platforms at the end of the experiment and percentage of the corals showing mortality. We conclude that lack of suitable hard substrate, macroalgal competition, and blockage of recruitment on available substratum are major factors accounting for the low natural coral coverage in areas of high turbidity. The direct impact of high turbidity on growth and mortality is of lesser importance.

  19. A Kinetic Study of the Emulsion Polymerization of Vinyl Acetate

    Friis, N.; Nyhagen, L.

    1973-01-01

    The emulsion polymerization of vinyl acetate was studied at 50°C. It was found that the rate of polymerization was proportional to the 0.5 power of the initiator concentration and the 0.25 power of the number of particles. The number of particles was proportional to the power 0.5 ± 0.05 of the...... emulsifier concentration, but independent of the initiator concentration. The limiting viscosity number of the polymers produced was independent of the initiator concentration and number of polymer particles. It is suggested that the mechanism of vinyl acetate emulsion polymerization is similar to that of...

  20. Overview on mechanisms of acetic acid resistance in acetic acid bacteria.

    Wang, Bin; Shao, Yanchun; Chen, Fusheng

    2015-02-01

    Acetic acid bacteria (AAB) are a group of gram-negative or gram-variable bacteria which possess an obligate aerobic property with oxygen as the terminal electron acceptor, meanwhile transform ethanol and sugar to corresponding aldehydes, ketones and organic acids. Since the first genus Acetobacter of AAB was established in 1898, 16 AAB genera have been recorded so far. As the main producer of a world-wide condiment, vinegar, AAB have evolved an elegant adaptive system that enables them to survive and produce a high concentration of acetic acid. Some researches and reviews focused on mechanisms of acid resistance in enteric bacteria and made the mechanisms thoroughly understood, while a few investigations did in AAB. As the related technologies with proteome, transcriptome and genome were rapidly developed and applied to AAB research, some plausible mechanisms conferring acetic acid resistance in some AAB strains have been published. In this review, the related mechanisms of AAB against acetic acid with acetic acid assimilation, transportation systems, cell morphology and membrane compositions, adaptation response, and fermentation conditions will be described. Finally, a framework for future research for anti-acid AAB will be provided. PMID:25575804

  1. Defining element associations and inferring geological processes from total element concentrations in Australian catchment outlet sediments: Multivariate analysis of continental-scale geochemical data

    Highlights: ► Australia-wide geochemical dataset of catchment outlet sediments covers 6 M km2. ► Total element concentrations analysed by PCA after imputation and clr-transformation. ► Four first PCs account for 59% of variance. ► Element associations show lithology, weathering, etc. control regolith composition. ► Maps of PC distributions relate to ground, airborne and spaceborne datasets. - Abstract: In this paper, the geochemical composition of surficial regolith is statistically analysed and compared to independent geoscientific datasets to infer processes governing regolith composition. Surface (0–10 cm depth) and sub-surface (∼60–80 cm depth) transported sediment samples from the National Geochemical Survey of Australia were analysed for total element content in both coarse (<2 mm) and fine (<75 μm) grain-size fractions. Multi-element total content data was obtained from mainly XRF and total digestion ICP-MS analysis, of which the 50 elements satisfying data quality criteria, plus Loss on Ignition, are used herein. Censored data (

  2. Catalytic Esterification of Methyl Alcohol with Acetic Acid

    2001-01-01

    Esterification of methyl alcohol with acetic acid catalysed by Amberlyst-15 (cation-exchange resin) was carried out in a batch reactor in the temperature ranging between 318-338 K, at atmospheric pressure. The reaction rate increased with increase in catalyst concentration and reaction temperature, but decreased with an increase in water concentration. Stirrer speed had virtually no effect on the rate under the experimental conditions. The rate data were correlated with a second-order kinetic model based on homogeneous reaction. The apparent activation energy was found to be 22.9kJ.mo1-1 for the formation of methyl acetate. The methyl acetate production was carried out aa batch and continuous in a packed bed restive distillation column with high purity methyl acetate produced.

  3. Comparison of growth, acetate production, and acetate inhibition of Escherichia coli strains in batch and fed-batch fermentations.

    Luli, G W; Strohl, W R

    1990-04-01

    The growth characteristics and acetate production of several Escherichia coli strains were compared by using shake flasks, batch fermentations, and glucose-feedback-controlled fed-batch fermentations to assess the potential of each strain to grow at high cell densities. Of the E. coli strains tested, including JM105, B, W3110, W3100, HB101, DH1, CSH50, MC1060, JRG1046, and JRG1061, strains JM105 and B were found to have the greatest relative biomass accumulation, strain MC1060 accumulated the highest concentrations of acetic acid, and strain B had the highest growth rates under the conditions tested. In glucose-feedback-controlled fed-batch fermentations, strains B and JM105 produced only 2 g of acetate.liter-1 while accumulating up to 30 g of biomass.liter-1. Under identical conditions, strains HB101 and MC1060 accumulated less than 10 g of biomass.liter-1 and strain MC1060 produced 8 g of acetate.liter-1. The addition of various concentrations of sodium acetate to the growth medium resulted in a logarithmic decrease, with respect to acetate concentration, in the growth rates of E. coli JM105, JM105(pOS4201), and JRG1061. These data indicated that the growth of the E. coli strains was likely to be inhibited by the acetate they produced when grown on media containing glucose. A model for the inhibition of growth of E. coli by acetate was derived from these experiments to explain the inhibition of acetate on E. coli strains at neutral pH. PMID:2187400

  4. Serum concentrations of type I and III procollagen propeptides in healthy children and girls with central precocious puberty during treatment with gonadotropin-releasing hormone analog and cyproterone acetate

    Hertel, Niels; Stoltenberg, Meredin; Juul, A;

    1993-01-01

    Serum levels of type I and III procollagen propeptides (s-PICP and s-PIIINP) were measured in 466 healthy school children and in 23 girls with central precocious puberty (CPP) during GnRH analog and cyproterone acetate therapy, using two commercially available RIAs. In normal children, s-PICP and s......-PIIINP levels to height velocity in girls (r = 0.35; P <0.001 and r = 0.33; P <0.001, respectively), while in boys, only s-PIIINP showed significant correlation to height velocity (r = 0.40; P <0.001). In untreated girls with CPP, serum levels of s-PIIINP were elevated [PIIINP SD score (SDS), 2.13]. Levels of s...

  5. KINETIC STUDY OF CARBONYLATION OF METHANOL TO ACETIC ACID AND ACETIC ANHYDRIDE OVER A NOVEL COPOLYMER- BOUND CIS- DICARBONYLRHODIUM COMPLEX

    CHEN Yuying; YUAN Guoqing; CHEN Rongyao

    1989-01-01

    The kinetic study of carbonylation of methanol-acetic acid mixture to acetic acid and acetic anhydride over a cis-dicarbonylrhodium complex (MVM' Rh)coordinated with the ethylene diacrylate (M')crosslinked copolymer of methyl acrylate (M) and 2 - vinylpyridine (V) shows that the rate of reaction is zero order with respect to both reactants methanol and carbon monoxide, but first order in the concentrations of promoter methyl iodide and rhodium in the complex . Polar solvents can accelerate the reaction .Activation parameters were calculated from the experimental results, being comparable to that of the homogeneous system . A mechanism similar to that of soluble rhodium catalyst was proposed .

  6. Relations of benthic macroinvertebrates to concentrations of trace elements in water, streambed sediments, and transplanted bryophytes and stream habitat conditions in nonmining and mining areas of the upper Colorado River basin, Colorado, 1995-98

    Mize, Scott V.; Deacon, Jeffrey R.

    2002-01-01

    Intensive mining activity and highly mineralized rock formations have had significant impacts on surface-water and streambed-sediment quality and aquatic life within the upper reaches of the Uncompahgre River in western Colorado. A synoptic study by the U.S. Geological Survey National Water-Quality Assessment Program was completed in the upper Uncompahgre River Basin in 1998 to better understand the relations of trace elements (with emphasis on aluminum, arsenic, copper, iron, lead, and zinc concentrations) in water, streambed sediment, and aquatic life. Water-chemistry, streambed-sediment, and benthic macroinvertebrate samples were collected during low-flow conditions between October 1995 and July 1998 at five sites on the upper Uncompahgre River, all downstream from historical mining, and at three sites in drainage basins of the Upper Colorado River where mining has not occurred. Aquatic bryophytes were transplanted to all sites for 15 days of exposure to the water column during which time field parameters were measured and chemical water-quality and benthic macroinvertebrate samples were collected. Stream habitat characteristics also were documented at each site. Certain attributes of surface-water chemistry among streams were significantly different. Concentrations of total aluminum, copper, iron, lead, and zinc in the water column and concentrations of dissolved aluminum, copper, and zinc were significantly different between nonmining and mining sites. Some sites associated with mining exceeded Colorado acute aquatic-life standards for aluminum, copper, and zinc and exceeded Colorado chronic aquatic-life standards for aluminum, copper, iron, lead, and zinc. Concentrations of copper, lead, and zinc in streambed sediments were significantly different between nonmining and mining sites. Generally, concentrations of arsenic, copper, lead, and zinc in streambed sediments at mining sites exceeded the Canadian Sediment Quality Guidelines probable effect level (PEL

  7. OU3 sediment dating and sedimentation rates

    Environmental Technologies at Rocky Flats Environmental Technology Site (RFS) investigated the sediment history of Standley Lake, Great Western Reservoir, and Mower Reservoir using 137Cs and 239,240Pu global fall-out as dating indicators. These Colorado Front Range reservoirs have been the subject of study by various city, state and national agencies due to suspected Department of Energy Rocky Flats Plant impacts. We performed sediment dating as part of the RCRA Facility Investigation/Remedial Investigation Report for Operable Unit 3. A sediment chronology profile assists scientist in determining the year of sedimentation for a particular peak concentration of contaminants. Radioisotope sediment dating for the three reservoirs indicated sedimentation rates of 0.7 to 0.8 in./yr. for Standley Lake (SL), 0.9 in./yr. for Great Western Reservoir (GWR), and 0.3 in./yr. in Mower Reservoir (MR). RFS sediment dating for Operable Unit 3 compared favorably with the Hardy, Livingston, Burke, and Volchok Standley Lake study. This report describes the cesium/plutonium sediment dating method, estimates sedimentation rates for Operable Unit 3 reservoirs, and compares these results to previous investigations

  8. Methane Production from Protozoan Endosymbionts Following Stimulation of Microbial Metabolism within Subsurface Sediments

    DawnElenaHolmes

    2014-08-01

    Full Text Available Previous studies have suggested that protozoa prey on Fe(III- and sulfate-reducing bacteria that are enriched when acetate is added to uranium contaminated subsurface sediments to stimulate U(VI reduction. In order to determine whether protozoa continue to impact subsurface biogeochemistry after these acetate amendments have stopped, 18S rRNA and ß-tubulin sequences from this phase of an in situ uranium bioremediation field experiment were analyzed. Sequences most similar to Metopus species predominated, with the majority of sequences most closely related to M. palaeformis, a cilitated protozoan known to harbor methanogenic symbionts. Quantification of mcrA mRNA transcripts in the groundwater suggested that methanogens closely related to Metopus endosymbionts were metabolically active at this time. There was a strong correlation between the number of mcrA transcripts from the putative endosymbiotic methanogen and Metopus ß-tubulin mRNA transcripts during the course of the field experiment, suggesting that the activity of the methanogens was dependent upon the activity of the Metopus species. Addition of the eukaryotic inhibitors cyclohexamide and colchicine to laboratory incubations of acetate-amended subsurface sediments significantly inhibited methane production and there was a direct correlation between methane concentration and Metopus ß-tubulin and putative symbiont mcrA gene copies. These results suggest that, following the stimulation of subsurface microbial growth with acetate, protozoa harboring methanogenic endosymbionts become important members of the microbial community, feeding on moribund biomass and producing methane.

  9. Comparison between some trace and heavy metals concentrations in sediments of a river and a natural wetland system in Ribeira do Iguape Basin, São Paulo State, Brazil

    Maria do Carmo Calijuri

    2007-07-01

    Full Text Available ResumoThe sediment is an integrator site of many processes that take place in the water column. Its study is extremely important for the assessment of environmental impacts to which aquatic ecosystems are subordinated, since the sediments are able to accumulate nutrients and pollutants. The aim of this research was to compare copper, lead, manganese and mercury concentrations in the sediments of Jacupiranguinha River and of a natural wetland, observing the spatial-temporal variation of these concentrations in two sampling periods: October, 2004 and January, 2005. The study area is located in one of the most miserable regions in Brazil, Ribeira do Iguape Basin, whose economy is based on banana cultivation and mining activities. The obtained results contributed to better understand the differences in contaminants´ dynamic for lotic and lentic biological systems. Copper, lead and manganese concentrations were higher in the natural wetland sediment when compared to the river, probably due to the variability of processes in one and other ecosystem. It was possible to observe temporal variation, since the highest concentrations of these three metals were obtained in the sampling during the rainy period. Mercury, however, presented a different behavior. The highest concentrations were obtained in Jacupiranguinha River, reaching 0.8 mg kg-1, painting a deep and serious public health problem. Besides, mercury concentrations during the rainy period were lower in comparison with the period with less intense precipitation, pointing the possibility of this metal’s transportation from Jacupiranguinha river to the other rivers located in the basin.

  10. 辐射沙脊群海域悬沙场遥感反演方法%Remote Sensing Retrieval of Suspended Sediment Concentration Field in Radial Sand Ridges Area

    潘进; 丁贤荣; 康彦彦; 葛小平; 李森

    2013-01-01

    Suspended sediment field has great significance in the study of sand ridge development and geomorphic evolution, also in the matter of tidal flat reclamation and coastal engineering. In this paper, on the basis of hydrology-sediment data obtained in JS9O8 investigation in 2006 and contemporaneous MODIS images, remote sensing quantitative retrieval model was established. Suspended sediment concentration distribution maps in different tide levels and mean sediment concentration distribution map of a half tidal cycle were obtained. The retrieval map was compared with the numerical simulation map using suspended sediment dynamic mathematical model. The result showed that: the precision of (B1-B4) / (B1+B4) logarithm mode was high. The remote sensing retrieval map was similar to the numerical simulation map. High-concentration region of suspended sediment were mainly located in near Jianggang, Feihuanghe estuary and Yangtze estuary. Retrieval map had more details than the simulation map. It can reflect clearly the influence of the estuaries, sandbars, waterways on the distribution of suspended sediment, and can provide technical support for the exploration of suspended sediment transport.%利用2006年江苏908调查水文泥沙测验数据和同期MODIS影像建立遥感定量反演模式,获取了半个潮周期的悬沙场以及全潮平均悬沙场,进行了辐射沙脊群海域悬沙场遥感反演方法的研究,并结合悬沙数学模型对结果进行了验证.研究表明,在辐射沙脊群海域,敏感参数(B1-B4)/(B1+B4)的对数模式反演悬沙场精度较高;遥感反演结果在总体上与数学模型计算结果相似,悬沙高值区主要分布在弶港、废黄河口和长江口附近;在细节上比数学模型表现得更精细,能清晰地反映河口、沙洲、水道等地貌对悬沙分布的影响.

  11. Detailed uranium geochemical stream sediment survey data release for selected portions of the Craig NTMS Quadrangle, Colorado, and Rawlins NTMS Quadrangle, Wyoming, including concentrations of forty-five additional elements

    This detailed study was undertaken at the request of the NURE Program Office, Grand Junction, Colorado, to aid in the evaluation of the uranium potential of the Browns Park and North Park formations in the area east of the Maybell-Lay, Colorado, uranium district and southeast of the Baggs, Wyoming, uranium district. A total of 1199 stream sediment samples was collected from 1199 locations in five areas in the quadrangle. The areas are designated Spring Creek, Hahns Peak, Elkhead Mountains, Yampa, and White River. All samples were collected at a nominal density of one sample location per 1.4 km2 Standardized field, analytical, and data base management procedures used during the sampling program are described briefly in the appendixes of this report. Elemental concentration, field measurement, weather, geologic, and geographic data for each sample location are listed in Appendix I. Uranium values range from 1.47 to 27.34 and have a mean of 3.53 ppM. Uranium/thorium ratios for sediment samples are also included in Appendix I. Sediments were analyzed for uranium and thorium as well as aluminum, antimony, arsenic, barium, beryllium, bismuth, cadmium, calcium, cerium, cesium, chlorine, chromium, cobalt, copper, dysprosium, europium, gold, hafnium, iron, lanthanum, lead, lithium, lutetium, magnesium, manganese, nickel, niobium, potassium, rubidium, samarium, scandium, selenium, silver, sodium, strontium, tantalum, terbium, tin, titanium, tungsten, vanadium, ytterbium, zinc, and zirconium (Appendix I). All sediments were analyzed for uranium by delayed neutron counting. Other elemental concentrations in sediments were determined by neutron activation analysis for 31 elements, by x-ray fluorescence for 12 elements, and by arc-source emission spectrography for 2 elements. Analytical results for sediments are reported as ppM

  12. Impact of uranyl-calcium-carbonato complexes on uranium(VI) adsorption to synthetic and natural sediments.

    Stewart, Brandy D; Mayes, Melanie A; Fendorf, Scott

    2010-02-01

    Adsorption on soil and sediment solids may decrease aqueous uranium concentrations and limit its propensity for migration in natural and contaminated settings. Uranium adsorption will be controlled in large part by its aqueous speciation, with a particular dependence on the presence of dissolved calcium and carbonate. Here we quantify the impact of uranyl speciation on adsorption to both goethite and sediments from the Hanford Clastic Dike and Oak Ridge Melton Branch Ridgetop formations. Hanford sediments were preconditioned with sodium acetate and acetic acid to remove carbonate grains, and Ca and carbonate were reintroduced at defined levels to provide a range of aqueous uranyl species. U(VI) adsorption is directly linked to UO(2)(2+) speciation, with the extent of retention decreasing with formation of ternary uranyl-calcium-carbonato species. Adsorption isotherms under the conditions studied are linear, and K(d) values decrease from 48 to 17 L kg(-1) for goethite, from 64 to 29 L kg (-1) for Hanford sediments, and from 95 to 51 L kg(-1) for Melton Branch sediments as the Ca concentration increases from 0 to 1 mM at pH 7. Our observations reveal that, in carbonate-bearing waters, neutral to slightly acidic pH values ( approximately 5) and limited dissolved calcium are optimal for uranium adsorption. PMID:20058915

  13. Simultaneous production of acetic and gluconic acids by a thermotolerant Acetobacter strain during acetous fermentation in a bioreactor.

    Mounir, Majid; Shafiei, Rasoul; Zarmehrkhorshid, Raziyeh; Hamouda, Allal; Ismaili Alaoui, Mustapha; Thonart, Philippe

    2016-02-01

    The activity of bacterial strains significantly influences the quality and the taste of vinegar. Previous studies of acetic acid bacteria have primarily focused on the ability of bacterial strains to produce high amounts of acetic acid. However, few studies have examined the production of gluconic acid during acetous fermentation at high temperatures. The production of vinegar at high temperatures by two strains of acetic acid bacteria isolated from apple and cactus fruits, namely AF01 and CV01, respectively, was evaluated in this study. The simultaneous production of gluconic and acetic acids was also examined in this study. Biochemical and molecular identification based on a 16s rDNA sequence analysis confirmed that these strains can be classified as Acetobacter pasteurianus. To assess the ability of the isolated strains to grow and produce acetic acid and gluconic acid at high temperatures, a semi-continuous fermentation was performed in a 20-L bioreactor. The two strains abundantly grew at a high temperature (41°C). At the end of the fermentation, the AF01 and CV01 strains yielded acetic acid concentrations of 7.64% (w/v) and 10.08% (w/v), respectively. Interestingly, CV01 was able to simultaneously produce acetic and gluconic acids during acetic fermentation, whereas AF01 mainly produced acetic acid. In addition, CV01 was less sensitive to ethanol depletion during semi-continuous fermentation. Finally, the enzymatic study showed that the two strains exhibited high ADH and ALDH enzyme activity at 38°C compared with the mesophilic reference strain LMG 1632, which was significantly susceptible to thermal inactivation. PMID:26253254

  14. Catalytic Combustion of Ethyl Acetate

    ÖZÇELİK, Tuğba GÜRMEN; ATALAY, Süheyda; ALPAY, Erden

    2007-01-01

    The catalytic combustion of ethyl acetate over prepared metal oxide catalysts was investigated. CeO, Co2O3, Mn2O3, Cr2O3, and CeO-Co2O3 catalysts were prepared on monolith supports and they were tested. Before conducting the catalyst experiments, we searched for the homogeneous gas phase combustion reaction of ethyl acetate. According to the homogeneous phase experimental results, 45% of ethyl acetate was converted at the maximum reactor temperature tested (350 °C). All the prepare...

  15. Concentrations of Inorganic and Organic Chemicals in Fish and Sediments from Major Tributaries of the Missouri River in North Dakota, 1989-91

    US Fish and Wildlife Service, Department of the Interior — Fish and sediments from the Missouri River and its major tributaries in North Dakota were collected in 1989 and 1991 and analyzed for organochlorines petroleum...

  16. Alaska Geochemical Database, Version 2.0 (AGDB2)--including “best value” data compilations for rock, sediment, soil, mineral, and concentrate sample media

    Granitto, Matthew; Schmidt, Jeanine; Shew, Nora B.; Gamble, Bruce M.; Labay, Keith A.

    2013-01-01

    The Alaska Geochemical Database Version 2.0 (AGDB2) contains new geochemical data compilations in which each geologic material sample has one “best value” determination for each analyzed species, greatly improving speed and efficiency of use. Like the Alaska Geochemical Database (AGDB, http://pubs.usgs.gov/ds/637/) before it, the AGDB2 was created and designed to compile and integrate geochemical data from Alaska in order to facilitate geologic mapping, petrologic studies, mineral resource assessments, definition of geochemical baseline values and statistics, environmental impact assessments, and studies in medical geology. This relational database, created from the Alaska Geochemical Database (AGDB) that was released in 2011, serves as a data archive in support of present and future Alaskan geologic and geochemical projects, and contains data tables in several different formats describing historical and new quantitative and qualitative geochemical analyses. The analytical results were determined by 85 laboratory and field analytical methods on 264,095 rock, sediment, soil, mineral and heavy-mineral concentrate samples. Most samples were collected by U.S. Geological Survey personnel and analyzed in U.S. Geological Survey laboratories or, under contracts, in commercial analytical laboratories. These data represent analyses of samples collected as part of various U.S. Geological Survey programs and projects from 1962 through 2009. In addition, mineralogical data from 18,138 nonmagnetic heavy-mineral concentrate samples are included in this database. The AGDB2 includes historical geochemical data originally archived in the U.S. Geological Survey Rock Analysis Storage System (RASS) database, used from the mid-1960s through the late 1980s and the U.S. Geological Survey PLUTO database used from the mid-1970s through the mid-1990s. All of these data are currently maintained in the National Geochemical Database (NGDB). Retrievals from the NGDB were used to generate

  17. Quantitative research for pollution levels in marine sediments of Ha Long Bay by nuclear technique

    Under the theme of Quantitative study of pollution levels in marine sediments of Halong bay by nuclear techniques conducted from June 2011 to June 2013, the authors conducted monitoring, sediment samples collected in the bay below the sediment column at 8 locations, in which 7 columns located at the estuary near Tuan Chau Island and 1 column at the area near the harbor of Cam Pha. The column samples were taken to the laboratory, cut slices with a distance of 2 cm in the form of frozen and conduct tests of radioactive Pb-210 to determine the rate of sediment in the survey area. Evaluation results based on the method by determining 210Pb, the sediment rate showed speed in the survey area ranged from 0.3 cm.a-1 to 1.2 cm.a-1 and an average of 1.0 cm.a-1. The slices of sediment samples (110 samples) were analyzed heavy metals (KLN) and As elemental by ICP-MS method. These sediment sample also were analyzed for simultaneous determination of N and P and total organic carbon (TOC). Results showed that heavy metal concentrations and As is smaller than the value specified in the National Technical Regulation on Sediment Quality of Vietnam (QCVN), phosphorus concentration less than that can cause harmful effects, but the concentration of total nitrogen and organic carbon that may exceed be harmful as directed by Canadian standards (Persuad et al. 1992). The concentration data in the Halong bay sediment were processed by statistical software SPSS-18, results showed high correlation between the quality TOC, N, P, K and correlation the majority of KLN, this proves the origin of sediments is part of the natural soil components and parts (TOC, N, P, K) is due to the activity of human activity as well as by agricultural fertilizers. The average content of elements in sediments Halong be compared with other data published works of sediment Quang Ninh area, the results show the correlation figures are also high. However, the results of the analysis of KLN and As in Halong sediment

  18. Characterisation of chitosan solubilised in aqueous formic and acetic acids

    Esam A. El-Hefian

    2009-01-01

    The intrinsic viscosity of chitosan (MW 7.9 x 105 g mol-1) having a high degree of deacetylation and solubilised in aqueous formic and acetic acids was determined at room temperature. Contact angle and conductivity of the chitosan solutions were also studied. The values of critical coagulation concentration (CCC) were then obtained from the plots of contact angle or conductivity versus concentration.

  19. Nomegestrol acetate: pharmacology, safety profile and therapeutic efficacy.

    Lello, Stefano

    2010-03-26

    This review summarizes the pharmacology, safety and clinical efficacy of nomegestrol acetate, based on the available published literature, and assesses the pharmacological characteristics that underlie a role in different gynaecological disorders and hormone replacement therapy (HRT), and a potential role in combination estrogen/progestogen oral contraception. Nomegestrol acetate is a potent, orally active progestogen with a favourable tolerability profile and neutral metabolic characteristics. Unlike the majority of older progestogens, which were 19-nortestosterone derivatives synthesized primarily for their antigonadotropic activity as a component of hormonal contraception in combination with an estrogen, nomegestrol acetate is a 19-norprogesterone derivative designed to bind specifically to the progesterone receptor, and is relatively lacking in affinity for other steroid receptors. Nomegestrol acetate exerts strong antiestrogenic effects at the level of the endometrium and has potent antigonadotropic activity, but without any residual androgenic or glucocorticoid properties. At a dosage of 1.25 mg/day, nomegestrol acetate inhibits ovulation while permitting follicle growth, whereas at dosages of 2.5 or 5 mg/day, both ovulation and follicle development are suppressed. The antigonadotropic action of nomegestrol acetate is mediated, like other progestins, at the hypothalamic and pituitary level. Moreover, nomegestrol acetate has partial antiandrogenic activity. Absorption of nomegestrol acetate is rapid after oral administration, reaching a peak serum concentration within 4 hours, with a terminal half-life of approximately 50 hours. Nomegestrol acetate has been used successfully for the treatment of some gynaecological disorders (menstrual disturbances, dysmenorrhoea, premenstrual syndrome) and as a component of HRT in combination with estradiol for the relief of menopausal symptoms; it has been approved in Europe as monotherapy for the treatment of the menopausal

  20. Cell morphology variations of Klebsiella pneumoniae induced by acetate stress using biomimetic vesicle assay.

    Lu, Shengguo; Han, Yuwang; Duan, Xujia; Luo, Fang; Zhu, Lingyan; Li, Shuang; Huang, He

    2013-10-01

    Supplementation with acetate under low levels was used as a novel approach to control the morphological development of Klebsiella pneumoniae aimed to improve 1,3-propanediol (1,3-PD) production. A full range of morphological types formed from rod shape to oval shape even round shape in response to different concentrations of acetate. The cell growth and 1,3-PD productions in the shake flasks with 0.5 g/L acetate addition were improved by 9.4 and 28.37%, respectively, as compared to the control, while the cell became shorter and began to lose its original shape. The cell membrane penetration by acetate was investigated by the biomimetic vesicles, while higher concentration of acetate led to more moderate colorimetric transitions. Moreover, the percentage composition of unsaturated fatty acid (UFA) was increased as well as the increased concentrations of acetate, whereas higher UFA percentage, higher fluidity of bacterial cell membrane. PMID:23892619

  1. Acetate catabolism by Methanosarcina barkeri

    Cell suspensions of Methanosarcina barkeri convert the carboxyl and methyl group carbons of acetate to carbon dioxide and methane at pH 6 under an atmosphere of 100% CO2. The rate of loss of radioactivity from [1-14C]acetate was over three times greater than that from [2-14C]acetate under these conditions. Control experiments with both labeled substrates present showed that the rates were additive. Addition of a high level of 2-bromoethanesulfonate to selectively inhibit methane formation largely inhibited release of 14C from methyl-labeled acetate but only marginally decreased the rate of loss from [1-14C]acetate. Thus, in the absence of the inhibitor loss of 14C from [1-14C]acetate likely reflects an isotopic exchange reaction with CO2 superimposed on the overall conversion of acetate to CO2 and CH4. The exchange reaction was inhibited by uncouplers such as 2,4-dinitrophenol, CCCP, and FCCP. Cells permeabilized by treatment with nonionic detergents or disrupted by passage through a French pressure cell failed to catalyze the exchange reaction. Exchange activity was not restored by addition of ATP or by use of [1-14C]acetyl CoA as substrate. No evidence for involvement of carbon monoxide dehydrogenase in the exchange was found in these experiments when CO2 was replaced by CO. However, the soluble extracts retained the ability to convert acetate to methane in the presence of H2 and ATP

  2. Acetate metabolism in Methanothrix soehngenii.

    Jetten, M. S. M.

    1991-01-01

    Acetate is quantitatively the most important intermediate in the anaerobic degradation of soluble organic matter. The conversion rate of acetate by methanogenic bacteria is proposed to be the rate limiting step in this degradation The study of acetoclastic methanogens, therefore is of relevance to our understanding of anaerobic processes and their optimal application in treatment of waste water from various sources.Until now only two genera of methane bacteria have been described which are ab...

  3. Phytotoxkit® and Ostracodtoxkit® tests for assessing the toxicity of sediment samples with high concentration of heavy metals

    Garcia-Lorenzo, Maria Luz; Martinez-Sanchez, Maria Jose; Molina, Jose; Hernandez-Cordoba, Manuel

    2010-05-01

    To estimate the risk of contaminants, chemical methods need to be complemented with biological methods. Ecotoxicological testing may be a useful approach for assessing the toxicity as a complement to chemical analysis. The aim of this study was to evaluate the sensitivity and applicability of two bioassays representing multiple trophic levels, for the preliminary ecotoxicological screening of sediments from sites contaminated by mining activities: a chronic toxicity test with the ostracod Heterocypris incongruens and a phytotoxicity test using Lepidium sativum, Sorghum saccharatum and Sinapis alba seeds. For this study, 30 soils samples were collected from the Sierra Minera (Murcia, SE Spain) for general analytical determinations and the total metal content (Pb, Zn, Cd and As) was determined. The Phytotoxkit® test measures the decrease in (or the absence of) seed germination and of the growth of the young roots after 3 days of exposure of seeds of selected higher plants to a contaminated matrix compared with the controls germinated in a reference soil. The plants selected for the Phytotoxkit® microbiotest were: the monocotyl Sorghum saccharatum (Sorgho) and the dicotyls Lepidium sativum (Garden cress) and Sinapis alba (mustard) (Phytotoxkit®, 2004). The percent inhibition of seed germination (SG) and root growth inhibition (RI) for each plant were calculated. Ostracodtoxkit® test consists of placing freshly hatched ostracod neonates in multiwell cups in 2 ml synthetic freshwater, with 300 µl sediment and 3x107 algal cells (Selenastrum capricornutum). After 6 days, incubation at 25 °C in darkness, the mortality of test organisms was determined (Ostracodtoxkit® FTM, 2001) and growth inhibition was calculated. Soil samples showed a mean pH value of 6.0 in water and 5.7 in KCl. The EC varied from 1.0 dS m-1 to 56.2 dS m-1, with a mean value of 17.7 dS m-1. The mean value for Pb was 0.84 mg kg-1, 10593 mg kg-1 for Zn, 23.18 mg kg-1 for Cd and 0.16 mg kg-1 for As

  4. Concentrations of geogenic heavy metals in meadowland sediments and soils in the Saale river catchment area. A contribution to the ecological assessment of heavy metal pollution in bodies of surface water

    In a joint project covering the main tributaries of the Elbe river, heavy metal concentrations in recent river sediments of the Saale river were measured. Apart from the most relevant pollutants (Cd, Zn, Pb, Cu, Cr, Ni, Hg, As), further metals and Se were also measured. The results provided information on the volumes, distribution, sources and regional distribution of heavy metal pollution as well as on the development of pollution with time since 1991. Natural (geogenic) metal concentrations are an issue as renaturing plans are being developed. In order to avoid unrealistic sanitation goals, an attempt was made to assess the distribution of the geogenic background values of fine-grained river sediments in part catchment areas of a large river catchment area (here: the Saale river) in order to obtain a standard regional geogenic background value for each element

  5. Precipitation Reaction of SDS and Potassium Salts in Flocculation of a Micronized Megestrol Acetate Suspension

    Hejazi, Seyed Mahdi; Erfan, Mohammad; MORTAZAVI, Seyed Alireza

    2013-01-01

    In this work attempts were made to evaluate K+-SDS and hydrocolloid polymer-SDS interactions in flocculation of megestrol acetate dispersions to enhance their stability as a part of suspension formulation. Different dispersions of micronized megestrol acetate and SDS were prepared. KCl and KH2PO4 and their corresponding sodium salts were added to the dispersions and the preparations were evaluated using general physicochemical and stability tests including appearance, sedimentation volume, se...

  6. Evaluating turbidity and suspended-sediment concentration relations from the North Fork Toutle River basin near Mount St. Helens, Washington; annual, seasonal, event, and particle size variations - a preliminary analysis.

    Uhrich, Mark A.; Spicer, Kurt R.; Mosbrucker, Adam; Christianson, Tami

    2015-01-01

    Regression of in-stream turbidity with concurrent sample-based suspended-sediment concentration (SSC) has become an accepted method for producing unit-value time series of inferred SSC (Rasmussen et al., 2009). Turbidity-SSC regression models are increasingly used to generate suspended-sediment records for Pacific Northwest rivers (e.g., Curran et al., 2014; Schenk and Bragg, 2014; Uhrich and Bragg, 2003). Recent work developing turbidity-SSC models for the North Fork Toutle River in Southwest Washington (Uhrich et al., 2014), as well as other studies (Landers and Sturm, 2013, Merten et al., 2014), suggests that models derived from annual or greater datasets may not adequately reflect shorter term changes in turbidity-SSC relations, warranting closer inspection of such relations. In-stream turbidity measurements and suspended-sediment samples have been collected from the North Fork Toutle River since 2010. The study site, U.S. Geological Survey (USGS) streamgage 14240525 near Kid Valley, Washington, is 13 river km downstream of the debris avalanche emplaced by the 1980 eruption of Mount St. Helens (Lipman and Mullineaux, 1981), and 2 river km downstream of the large sediment retention structure (SRS) built from 1987–1989 to mitigate the associated sediment hazard. The debris avalanche extends roughly 25 km down valley from the edifice of the volcano and is the primary source of suspended sediment moving past the streamgage (NF Toutle-SRS). Other significant sources are debris flow events and sand deposits upstream of the SRS, which are periodically remobilized and transported downstream. Also, finer material often is derived from the clay-rich original debris avalanche deposit, while coarser material can derive from areas such as fluvially reworked terraces.

  7. Concentration, distribution, and translocation of mercury and methylmercury in mine-waste, sediment, soil, water, and fish collected near the Abbadia San Salvatore mercury mine, Monte Amiata district, Italy

    Rimondi, V.; Gray, J.E.; Costagliola, P.; Vaselli, O.; Lattanzi, P.

    2012-01-01

    The distribution and translocation of mercury (Hg) was studied in the Paglia River ecosystem, located downstream from the inactive Abbadia San Salvatore mine (ASSM). The ASSM is part of the Monte Amiata Hg district, Southern Tuscany, Italy, which was one of the world’s largest Hg districts. Concentrations of Hg and methyl-Hg were determined in mine-waste calcine (retorted ore), sediment, water, soil, and freshwater fish collected from the ASSM and the downstream Paglia River. Concentrations of Hg in calcine samples ranged from 25 to 1500 μg/g, all of which exceeded the industrial soil contamination level for Hg of 5 μg/g used in Italy. Stream and lake sediment samples collected downstream from the ASSM ranged in Hg concentration from 0.26 to 15 μg/g, of which more than 50% exceeded the probable effect concentration for Hg of 1.06 μg/g, the concentration above which harmful effects are likely to be observed in sediment-dwelling organisms. Stream and lake sediment methyl-Hg concentrations showed a significant correlation with TOC indicating considerable methylation and potential bioavailability of Hg. Stream water contained Hg as high as 1400 ng/L, but only one water sample exceeded the 1000 ng/L drinking water Hg standard used in Italy. Concentrations of Hg were elevated in freshwater fish muscle samples and ranged from 0.16 to 1.2 μg/g (wet weight), averaged 0.84 μg/g, and 96% of these exceeded the 0.3 μg/g (methyl-Hg, wet weight) USEPA fish muscle standard recommended to protect human health. Analysis of fish muscle for methyl-Hg confirmed that > 90% of the Hg in these fish is methyl-Hg. Such highly elevated Hg concentrations in fish indicated active methylation, significant bioavailability, and uptake of Hg by fish in the Paglia River ecosystem. Methyl-Hg is highly toxic and the high Hg concentrations in these fish represent a potential pathway of Hg to the human food chain.

  8. [A comparative study between low-dose and high-dose medroxyprogesterone acetate (MPA) in the treatment of advanced and recurrent breast cancer--in relation to dose, serum concentration and response. Osaka Breast Cancer Research Group].

    Furukawa, J; Yayoi, E; Takatsuka, Y; Aikawa, T; Maeura, Y; Kobayashi, T; Miyauchi, K; Kotsuma, Y

    1997-05-01

    A prospective randomized study was carried out to evaluate the effectiveness of MPA in the treatment of breast cancer by comparing low dose (600 mg/day) with high dose (1,200 mg/day) of MPA. In 35 evaluable cases, the response rate to treatment was 40.0% (8/20) with low dose MPA and 26.7% (4/15) with high dose MPA. There was no significant difference between the two groups. The serum MPA concentration measured by high-performance liquid chromatography (HPLC) assay was 23.2 +/- 17.6 ng/ml in the low-dose group and 89.5 +/- 56.7 ng/ml in the high-dose group. Intrapatient variability in serum MPA concentration was relatively stable, but interpatient variability was large. No correlation was found between the response rate and serum MPA concentration. The above results indicate that a low dose of MPA (600 mg/day) is a useful treatment with high effectiveness and safety in advanced and recurrent breast cancer patients. Though no exact data on the optimal serum concentration could not be obtained, it was obvious that a successful response cannot be expected from a serum MPA concentration of less than 17 ng/ml, which was the average serum concentration in NC and PD patients of the low-dose group. PMID:9170519

  9. 基于MODIS影像估算鄱阳湖泥沙浓度及其时空变化%Estimation of Poyang Lake Sediment Concentration and Its Temporal and Spatial Distribution Based MODIS Image

    刘德坤; 齐述华

    2013-01-01

    悬浮泥沙浓度是衡量水质的重要指标之一,估算其泥沙浓度及获得其在空间和时间上的分布信息对于保护与管理湖泊生态系统是有利的。该研究以鄱阳湖区域为例,利用MODIS。感影像,并结合反演模型对鄱阳湖区域的悬浮泥沙浓度进行反演。结果显示:2010年鄱阳湖悬浮泥沙浓度呈明显的时间和空间分布特征。%Suspended sediment concentration was one of the important parameters to evaluate water quality,evaluating and obtaining the information of temporal and spatial distribution was benefical to the management and protection of lakes ecosystem. Taking Poyang Lake area as an example,combined with inversion model,Poyang Lake area suspended sediment concentration was inversed by using MODIS remote sensing image,The results showed that the suspended sediment concentration of Poyang Lake had obviously temporal and spatial distribution characteristics in 2010.

  10. Concentration of heavy metals, Mn, Fe, Ni, Pb, Cr and Cd in bottom sediments of the Outer Songkhla Lake deposited between the year B.E. 2520-2538

    Bhongsuwan, T.

    2002-01-01

    Full Text Available The study aimed to analyse the heavy metals Mn, Fe, Ni, Pb, Cr and Cd in 20 bottom sedimentsamples from 0 - 9 cm depth collected in 4 sites in the Outer Songkhla Lake. These sediment samples were deposited during the year B.E. 2520-2538 according to the Cs-137 dating. Total acid digestion was used to totally dissolve the samples using aqua regia and hydrofluoric acids. A quality control was performed by digesting the certified reference material IAEA SL-1 (lake sediment. Percent recoveries of selected heavy metals were between 79.96 (Ni and 99.26 (Cr. Concentrations of Mn, Fe, Ni, Pb and Cr in the sediment samples were in ranges 368-756, 21014-36683, 1.1-16.7, 24.5-59.8 and 30.1-67.5 mg/kg, respectively.Cadmium was non-detectable but calculated to be less than 2.5 mg/kg in all samples. Result showed thatMn has significantly increased between the depth 9-0 cm (the deposition years B.E. 2520-2538, while Fe,Ni, Pb and Cr had not changed significantly. It was concluded that Mn, Fe, Ni and Cr were still in low concentration comparable to those of sediments in several remote lakes worldwide both in Europe and America. Only Pb concentration was found to be higher than that in remote lakes worldwide. Iron was found to be the best conservative element in the outer Songkhla Lake. Regional anomaly criteria showed that Mn, Ni, Pband Cr in most samples were within the natural geochemical population except for Ni in one sample of coreU, which was considered to be a regional anomaly. Geoaccumulation index calculated in comparison with heavy metal concentration in average shale showed that sediment samples of the outer Songkhla Lake were not polluted by Mn, Fe, Ni, Cr at any site, and were unpolluted/moderately polluted for Pb at site T. Analysis of the magnetic susceptibility and the heavy metal contents in sediments showed no clear relation between them.

  11. Seasonal mercury concentrations and {delta}{sup 15}N and {delta}{sup 13}C values of benthic macroinvertebrates and sediments from a historically polluted estuary in south central Chile

    Diaz-Jaramillo, Mauricio, E-mail: mdiazjaramillo@conicet.gov.ar [Aquatic Systems Research Unit, EULA Chile Environmental Sciences Centre, Universidad de Concepcion (Chile); Munoz, Claudia; Rudolph, Ignacio [Aquatic Systems Research Unit, EULA Chile Environmental Sciences Centre, Universidad de Concepcion (Chile); Servos, Mark [Department of Biology, University of Waterloo, ON (Canada); Barra, Ricardo [Aquatic Systems Research Unit, EULA Chile Environmental Sciences Centre, Universidad de Concepcion (Chile)

    2013-01-01

    The Lenga Estuary is one of the most industrialized sites in south central Chile where the historic operation of chlor-alkali plants resulted in large quantities of mercury (Hg) being deposited into the estuary. This historical contamination may still represent a risk to the biota in the estuary. To investigate this four macroinvertebrates, Neotrypaea uncinata (ghostshrimp), Elminius kingii (barnacle), Hemigrapsus crenulatus (shore crab) and Perinereis gualpensis (ragworm) were collected seasonally from three different sites in the Lenga Estuary and one in a reference estuary (Tubul Estuary), and analyzed for Hg and stable isotopes ({delta}{sup 15}N and {delta}{sup 13}C). Mercury concentrations in Lenga sediments ranged from 0.4 {+-} 0.1 to 13 {+-} 3 mg/kg, while those in Tubul sediments ranged from 0.02 {+-} 0.01 to 0.07 {+-} 0.09 mg/kg. Total Hg concentrations of invertebrates were significantly different between estuaries (p < 0.05), but not by species or season for each estuary (p > 0.05). In contrast, organic Hg concentrations were different by species and season with shore crab muscle tissues exhibiting the greatest percent difference. Site-specific relationships demonstrated that total Hg concentrations in ragworm best reflected the total Hg sediment mercury concentrations. Signatures of {delta}{sup 13}C were correlated to the organic Hg % rather than total Hg. This suggests that organic Hg concentrations in these species were related to the carbon sources. -- Highlights: Black-Right-Pointing-Pointer Hg in sediments and biota from Lenga Estuary were elevated compared to nearby estuary. Black-Right-Pointing-Pointer Invertebrates showed interspecific and seasonal differences in terms of organic Hg %. Black-Right-Pointing-Pointer Total Hg levels in the ragworm best reflect Hg sediment gradient in Lenga Estuary. Black-Right-Pointing-Pointer Interspecific variation in {delta}{sup 13}C signatures indicated different feeding modes. Black

  12. Analyzing turbidity, suspended-sediment concentration, and particle-size distribution resulting from a debris flow on Mount Jefferson, Oregon, November 2006

    Uhrich, Mark A.

    2010-01-01

    A debris flow and sediment torrent occurred on the flanks of Mt Jefferson in Oregon on November 6, 2006, inundating 150 acres of forest. The massive debris flow was triggered by a rock and snow avalanche from the Milk Creek glaciers and snowfields during the early onset of an intense storm originating near the Hawaiian Islands. The debris flow consisted of a heavy conglomerate of large boulders, cobbles, and coarse-grained sediment that was deposited at depths of up to 15 ft and within 3 mi of the glaciers, and a viscous slurry that deposited finer-grained sediments at depths of 0.5 to 3 ft. The muddy slurry coated standing trees within the lower reaches of Milk Creek as it moved downslope.

  13. Concentrations and Fractionation of Carbon, Iron, Sulfur, Nitrogen and Phosphorus in Mangrove Sediments Along an Intertidal Gradient (Semi-Arid Climate, New Caledonia)

    Jonathan Deborde; Cyril Marchand; Nathalie Molnar; Luc Della Patrona; Tarik Meziane

    2015-01-01

    In mangrove ecosystems, strong reciprocal interactions exist between plant and substrate. Under semi-arid climate, Rhizophora spp. are usually predominant, colonizing the seashore, and Avicennia marina develops at the edge of salt-flats, which is the highest zone in the intertidal range. Along this zonation, distribution and speciation of C, Fe, S, N, and P in sediments and pore-waters were investigated. From the land-side to the sea-side of the mangrove, sediments were characterized by I/ in...

  14. Effect of nitrate, organic carbon, and temperature on potential denitrification rates in nitrate-rich riverbed sediments

    Pfenning, K.S.; McMahon, P.B.

    1997-01-01

    A study conducted in 1994 as part of the US Geological Survey's National Water-Quality Assessment Program, South Platte River Basin investigation, examined the effect of certain environmental factors on potential denitrification rates in nitrate-rich riverbed sediments. The acetylene block technique was used to measure nitrous oxide (N2O) production rates in laboratory incubations of riverbed sediments to evaluate the effect of varying nitrate concentrations, organic carbon concentrations and type, and water temperature on potential denitrification rates. Sediment incubations amended with nitrate, at concentrations ranging from 357 to 2142 ??mol l-1 (as measured in the field), produced no significant increase (P > 0.05) in N2O production rates, indicating that the denitrification potential in these sediments was not nitrate limited. In contrast, incubations amended with acetate as a source of organic carbon, at concentrations ranging from 0 to 624 ??mol l-1, produced significant increases (P organic carbon concentration, indicating that the denitrification potential in these sediments was organic carbon limited. Furthermore, N2O production rates also were affected by the type of organic carbon available as an electron donor. Acetate and surface-water-derived fulvic acid supported higher N2O production rates than groundwater-derived fulvic acid or sedimentary organic carbon. Lowering incubation temperatures from 22 to 4??C resulted