Sediment and toxic contaminant transport modeling in coastal waters

International Nuclear Information System (INIS)

Onishi, Yasuo; Mayer, D.W.; Argo, R.S.

1982-01-01

Models are presented to estimate the migration of toxic contaminants in coastal waters. Ocean current is simulated by the vertically-averaged, finite element, two-demensional model known as CAFE-I with the Galerkin weighted residual technique. The refraction of locally generated waves or swells is simulated by the wave refraction model, LO3D. Using computed current, depth, and wave characteristics, the finite element model, FETRA, simulated sediment and contaminant transport in coastal waters, estuaries and rivers. Prior to the application of these models to the Irish Sea and other coastal waters, the finite element model, FETRA, was tested to demonstrate its ability to simulate sediment and contaminant interaction, and the mechanism governing the transport, deposition, and resuspension of contaminated sediment. Several simple equations such as the unsteady, advection-diffusion equation, the equation for noncohesive-sediment load due to wind-induced waves in offshore and surf zones, and the equation for sediment-radionuclide transport simulation were solved during the preliminary testing of the model. (Kato, T.)

Effect of zinc-enriched natural sediments, in isolated and microcosm models, on three species of benthic invertebrates

International Nuclear Information System (INIS)

Galar Martinez, Marcela; Martinez-Tabche, Laura; Sanchez-Hidalgo, Eugenia; Lopez Lopez, Eugenia

2006-01-01

Availability of toxic in aquatic bodies is limited by the physicochemical characteristics of sediments and water, as well as by the interactions between the different xenobiotics and inhabits species. The aim of this work was to relate the effect produced by zinc (Zn) spiked in sediments of the Ignacio Ramirez dam (PIR), in isolated and microcosm models, on ATP concentration of three benthic organisms with the metal biodisponibility. The selected species were a crustacean, an annelid and a mollusk: Hyalella azteca (Amphipoda: Hyalellidae), Limnodrilus hoffmeisteri (Oligochaeta: Tubificidae) and Stagnicola attenuata (Basommatophora: Lymnaeidae), species that are found at high proportions in the reservoir and use different spaces in the benthos. Samples of sediments and organisms were collected from the PIR during the dry season (February of 1999). Metal concentration (Zn, Fe, Cu and Ni), pH, texture, particle size, total nitrogen and organic matter were determined in sediments. Sublethal studies were carried out using two types of static systems (isolated and in microcosm organisms). Both models contained PIR sediments enriched with Zn (nominal concentration of 0.8129 mg/kg) and synthetic water in a proportion of 1:4. The test organisms were added to the systems once the equilibrium was reached (2 hr) considering the biomass quantity with respect to volume (1.0 g of organism by each 100 ml of water:sediment). After 0, 12, 24, 36, 48 and 72 hr of exposure, samples of sediment and hydrobionts were taken, and Zn content was quantified by atomic absorption. ATP concentration was also determined in organisms. The effect produced by natural sediments spiked with Zn is increased by the presence of more than one specie in the system (microcosm). With respect to Zn levels, two of the organisms (L. hoffmeisteri y S. attenuata) tend to lose this metal in isolated and microcosm models, probably as a regulation strategy in its accumulation, as well as Fe presence in the

Competition between two wetland macrophytes under different levels of sediment saturation

Directory of Open Access Journals (Sweden)

Feng Li

2015-02-01

Full Text Available Plant-plant interactions have been widely studied under various environmental conditions. However, in wetland ecosystems how plant interactions change in response to variation in sediment saturation remains largely unclear, even though different levels of sediment saturation play important roles in determining plant growth performance in wetland ecosystems. To this end, a competition experiment with two typical wetland species, Carex brevicuspis (neighbor plant and Polygonum hydropiper (target plant, was conducted in a target-neighbor design. Two water levels (0 cm and -40 cm water levels representing waterlogged and drained sediments, respectively and three neighbor plant densities (0 plants m-2, 400 plants m-2, and 1600 plants m-2 were tested in a factorial design. Biomass accumulation of P. hydropiper decreased along with enhanced C. brevicuspis density in the waterlogged treatment. However, in the drained treatment, biomass accumulation did not change under two C. brevicuspis densities. Above-ground relative neighbor effect index (ARNE and relative neighbor effect index (RNE of C. brevicuspis on P. hydropiper increased along with enhanced C. brevicuspis density only under waterlogged conditions. The below-ground relative neighbor effect index (BRNE was not affected at the different water level and density treatments. The below-ground mass fraction of P. hydropiper was much higher in the waterlogged treatment than it was in the drained one, especially with no C. brevicuspis treatment. However, the leaf mass fraction displayed the opposite pattern. The longest root length of P. hydropiper was much shorter under waterlogged treatment than under the drained treatment. These results suggest that the competition intensity of C. brevicuspis to P. hydropiper increased along with increasing C. brevicuspis density only under waterlogged conditions. Moreover, this study also confirms that P. hydropiper can acclimate to water stress mainly through

Sediment-water gas exchange in two Swedish lakes measured by Eddy Correlation

Science.gov (United States)

Kokic, J.; Sahlee, E.; Brand, A.; Sobek, S.

2014-12-01

Lake sediments are hotspots for carbon (C) cycling, acting both as sinks and sources through C burial and production of carbon dioxide (CO2) and methane. The fate of this CO2 in the water column is controlled by bottom water turbulence, a factor not accounted for in current estimates of sediment CO2 fluxes. This study is aimed to quantify the turbulent CO2 flux across the sediment-water interface (SWI) by measuring the oxygen (O2) flux with the non-invasive Eddy Correlation (EC) method that combines measurements of 3D velocity (ADV) and O2 fluctuations with a microsensor. Using the metabolic relation (respiratory quotient, RQ) of O2 and CO2 derived from a sediment incubation experiment we present the first estimates of turbulent lake sediment CO2 flux from two boreal lakes in Sweden (Erssjön and Erken, 0.07 km2 and 23.7 km2 respectively). Only ~10 % of the total dataset was extracted for flux calculations due to poor signal-to-noise ratio in the velocity and O2 signals. The sediment in Lake Erssjön was both consuming and producing O2, related to bacterial respiration and photosynthesis. Mean O2 flux was -0.19 and 0.17 μmol O2 m-2 sec-1, comparing to 0.04 μmol O2 m-2 sec-1 derived from the sediment incubation experiment. Fluxes for Lake Erken are still to be determined. Experimentally derived RQ of the both lake sediments were close to unity implying that in-situ CO2 fluxes are of similar magnitude as O2 fluxes, varying between -0.15 and 0.18 μmol C m-2 sec-1. The first measurement of turbulent sediment O2 flux and estimate of turbulent CO2 flux from a small boreal lake show higher and more variable fluxes than previously found in experimental studies. The low amount of data extracted for flux calculations (~10%) point towards the difficulties in EC measurement in low-turbulence environments. On-going work focuses on the turbulence structure in lakes and its influence on the gas fluxes at the SWI.

Toxicity of silicon carbide nanowires to sediment-dwelling invertebrates in water or sediment exposures

Science.gov (United States)

Mwangi, Joseph N.; Wang, Ning; Ritts, Andrew; Kunz, James L.; Ingersoll, Christopher G.; Li, Hao; Deng, Baolin

2011-01-01

Silicon carbide nanowires (SiCNW) are insoluble in water. When released into an aquatic environment, SiCNW would likely accumulate in sediment. The objective of this study was to assess the toxicity of SiCNW to four freshwater sediment-dwelling organisms: amphipods (Hyalella azteca), midges (Chironomus dilutus), oligochaetes (Lumbriculus variegatus), and mussels (Lampsilis siliquoidea). Amphipods were exposed to either sonicated or nonsonicated SiCNW in water (1.0 g/L) for 48 h. Midges, mussels, and oligochaetes were exposed only to sonicated SiCNW in water for 96 h. In addition, amphipods were exposed to sonicated SiCNW in whole sediment for 10 d (44% SiCNW on dry wt basis). Mean 48-h survival of amphipods exposed to nonsonicated SiCNW in water was not significantly different from the control, whereas mean survival of amphipods exposed to sonicated SiCNW in two 48-h exposures (0 or 15% survival) was significantly different from the control (90 or 98% survival). In contrast, no effect of sonicated SiCNW was observed on survival of midges, mussels, or oligochaetes. Survival of amphipods was not significantly reduced in 10-d exposures to sonicated SiCNW either mixed in the sediment or layered on the sediment surface. However, significant reduction in amphipod biomass was observed with the SiCNW either mixed in sediment or layered on the sediment surface, and the reduction was more pronounced for SiCNW layered on the sediment. These results indicated that, under the experimental conditions, nonsonicated SiCNW in water were not acutely toxic to amphipods, sonicated SiCNW in water were acutely toxic to the amphipods, but not to other organisms tested, and sonicated SiCNW in sediment affected the growth but not the survival of amphipods.

Effects of light and microbial activity on the degradation of two fluoroquinolone antibiotics in pond water and sediment.

Science.gov (United States)

Lin, Juo-Shan; Pan, Hung-Yu; Liu, Shiu-Mei; Lai, Hong-Thih

2010-07-01

Enrofloxacin (ENR) and ciprofloxacin (CIP) are two fluoroquinolone (FQ) antibiotics widely used to treat diseases of human beings and cultured animals. These two FQs are usually detected in the effluent of municipal sewage plants and related aquatic environments. The purpose of this study was to understand the fates of ENR and CIP in aquaculture pond water and a sediment slurry in a laboratory-scale experiment. Effects of light and microbial activity on the degradation of these two FQs were investigated. Results indicated that natural irradiation plays a major role in the degradation of ENR and CIP in pond water and the sediment slurry. The 50 % dissipation times (DT(50)) with non-sterile treatment were 0.01 and 18.4 d for ENR, and 0.04 and 17.3 d for CIP in the water and sediment slurry, respectively. On the other hand, the degradation of ENR and CIP under dark conditions was slow or even hindered, and all of their DT(50) values exceeded 100 d. These two FQs degraded faster in the sediment slurry than in pond water under dark conditions. Artificial ultraviolet (UV) and fluorescence light had similar effects on the degradation of ENR in the pond water and sediment slurry. Degradation of CIP was faster with UV than with fluorescence light treatment, while no such difference was found for ENR degradation. CIP was a degradation product of ENR under both light and dark conditions, and DT(50) values for both compounds were shorter in the presence of light. The phenomenon of biodegradation was observed during degradation of CIP in the sediment slurry under natural light.

Effect of the settlement of sediments on water infiltration in two urban infiltration basins

OpenAIRE

LASSABATERE, Laurent; ANGULO JARAMILLO, R; GOUTALAND, David; LETELLIER, Laetitia; GAUDET, JP; WINIARSKI, Thierry; DELOLME, C

2010-01-01

The sealing of surfaces in urban areas makes storm water management compulsory. The suspended solids from surface runoff water accumulate in infiltration basins and may impact on water infiltration. This paper describes a study of the effect of the settlement of sedimentary layers on the water infiltration capacity of two urban infiltrations basins. In situ water infiltration experiments were performed (1) to quantify the effect of sediment on water infiltration at local scale and (2) to deri...

Macrobenthic diversity and sediment-water exchanges of oxygen and ammonium: Example of two subtidal communities of the eastern English Channel

Science.gov (United States)

Tous Rius, Armonie; Denis, Lionel; Dauvin, Jean-Claude; Spilmont, Nicolas

2018-06-01

In organic-rich shallow habitats, benthic macrofauna is known to play a major role in the geochemical functioning of surficial sediments through its metabolism, as well as its bioirrigation and/or bioturbation activity. In this paper, the effects of benthic macrofauna on metabolic fluxes at the sediment-water interface were studied at four dates, from winter to late summer, on two major macrobenthic communities of the eastern English Channel (macrotidal system): the fine sand Abra alba community (2 stations) and the sandy gravel Ophiothrix fragilis community (1 station). Oxygen and ammonium fluxes showed temporal changes that could be attributed to the variation of sea water temperature. Once the effect of temperature removed (using Q10 = 2.5), the average fauna mediated fluxes (FFauna) represented respectively 77% and 76% of average total fluxes. Considering the whole dataset, species number and biomass showed a significant correlation with fauna mediated fluxes of O2 and NH4+, while the relationships with abundance were not significant. The species composition of the community might influence ecosystem functioning, but in the present study, functional groups have a very poor relationship with FFauna (O2) and FFauna (NH4+). Despite the presence of engineer species, establishing general and simple rules to link macrofaunal parameters to functional attributes remains very difficult, suggesting that communities rather followed the idiosyncrasy and rivet hypothesis.

Nonlinear acoustics of water-saturated marine sediments

DEFF Research Database (Denmark)

Jensen, Leif Bjørnø

1976-01-01

Interest in the acoustic qualities of water-saturated marine sediments has increased considerably during recent years. The use of sources of high-intensity sound in oil propsecting, in geophysical and geological studies of bottom and subbottom materials and profiles and recently in marine...... archaeology has emphasized the need of information about the nonlinear acoustic qualities of water-saturated marine sediments. While the acoustic experiments and theoretical investigations hitherto performed have concentrated on a determination of the linear acoustic qualities of water-saturated marine...... sediments, their parameters of nonlinear acoustics are still unexplored. The strong absorption, increasing about linearly with frequency, found in most marine sediments and the occurrence of velocity dispersion by some marine sediments restrict the number of nonlinear acoustic test methods traditionally...

BOGDAŁÓW SEDIMENT TRAP OF DIRTY WATERS AS AN ECO-HYDROLOGICAL OBJECT

Directory of Open Access Journals (Sweden)

Mirosława Gilewska

2015-11-01

Full Text Available Sediment traps of dirty waters are, generally speaking, temporary hydrotechnical constructions associated with the purification of mine waters from mineral-organic suspensions. Once coal mining is finished and artificial supplies are cut off, such sediment traps – depending on hydrological and hydrotechnical conditions – undergo drainage or are utilised as water reservoirs. Drained sediment traps most commonly go through a period of self-generated reclamation – renaturalisation and become, similarly to water reservoirs, eco-hydrological objects. Bearing in mind the fact that the role of sediment traps is cleaning dirty waters, it seemed advisable to recognise the properties of sediments accumulated in them and to assess their impact on the arising plant communities. Two years after its closure, the entire area of the sediment trap (16 ha was subjected to soil science and phytosociological investigation. Differentiated moisture content and soil conditions of the sediment tank surface were favourable for the settlement of various species characterised by differing site requirements which conferred a completely new quality to this post-industrial land and its biodiversity. The invasion of herbaceous and woody plants indicates that despite the function of sediment tank played earlier in the brown coalmine infrastructure, the material which was accumulated in it provided a favourable habitat for the development of plant cover. It may be assumed that it can be attributed to a significant admixture of brown coal.

Arsenic mobility from anthropogenic impoundment sediments - Consequences of contamination to biota, water and sediments, Posa, Eastern Slovakia

Energy Technology Data Exchange (ETDEWEB)

Hiller, E.; Jurkovic, L.; Kordik, J.; Slaninka, I.; Jankular, M.; Majzlan, J.; Gottlicher, J.; Steininger, R. [Geological Survey of Slovak Republic, Bratislava (Slovakia). Dept. of Environmental Geochemistry

2009-11-15

An impoundment located near the village of Posa, Slovakia, is a significant source of contamination with As originating from the deposited coal fly-ash. Waters penetrating the impoundment are enriched in As and other potentially toxic elements. As a consequence of the contamination, the Kyjov Brook and the Ondava River have been extensively polluted. The mobility and solid-state partitioning of As in the impoundment material and stream sediments were investigated using column leaching and batch extraction tests, and a five-step sequential extraction procedure. Moreover, to investigate the bioavailability of As, two native plant species (Typha latifolia, or cattail, and Phragmites australis, or common reed) growing at the site were collected and analyzed. The As concentrations in representative sediment and water samples ranged from 36.3 to 3210 mg/kg and from 4.05 to 613 {mu} g/L, respectively, both being many times above the background levels. Although a part of As was present in a readily soluble form (6.6%), the majority of As was mainly associated with Fe and Mn oxides (37%) and residual phases (51%). Combined results of the column leaching, batch extraction, and sequential extraction tests, as well as mineralogical analysis, indicated that As mobilisation potential from the sediments is likely controlled by Fe, Al and Mn oxides, and by pH. There was no influence of various anions (PO{sub 4}{sup 3-}, SO{sub 4}{sup 2-}, NO{sup 3-}, Cl{sup -} and HCO{sub 3}{sup -}) on As mobility when present in aqueous solution at concentrations analogous to those in the water of the Kyjov Brook. Plants growing in the impoundment had As concentrations 10-100 times greater than did the same plants growing in a relatively non-polluted area.

The study on three-dimensional mathematical model of river bed erosion for water-sediment two-phase flow

Science.gov (United States)

Fang, Hongwei

1996-02-01

Based on the tensor analysis of water-sediment two-phase flow, the basic model equations for clear water flow and sediment-laden flow are deduced in the general curve coordinates for natural water variable-density turbulent flow. Furthermore, corresponding boundary conditions are also presented in connection with the composition and movement of non-uniform bed material. The theoretical results are applied to the calculation of the float open caisson in the construction period and good results are obtained.

Towards more ecological relevance in sediment toxicity testing with fish: Evaluation of multiple bioassays with embryos of the benthic weatherfish (Misgurnus fossilis).

Science.gov (United States)

Schreiber, Benjamin; Fischer, Jonas; Schiwy, Sabrina; Hollert, Henner; Schulz, Ralf

2018-04-01

The effects of sediment contamination on fish are of high significance for the protection of ecosystems, human health and economy. However, standardized sediment bioassays with benthic fish species, that mimic bioavailability of potentially toxic compounds and comply with the requirements of alternative test methods, are still scarce. In order to address this issue, embryos of the benthic European weatherfish (Misgurnus fossilis) were exposed to freeze-dried sediment (via sediment contact assays (SCA)) and sediment extracts (via acute fish embryo toxicity tests) varying in contamination level. The extracts were gained by accelerated solvent extraction with (i) acetone and (ii) pressurized hot water (PHWE) and subsequently analyzed for polycyclic aromatic hydrocarbons, polychlorinated biphenyls and polychlorinated dibenzodioxins and dibenzofurans. Furthermore, embryos of the predominately used zebrafish (Danio rerio) were exposed to extracts from the two most contaminated sediments. Results indicated sufficient robustness of weatherfish embryos towards varying test conditions and sensitivity towards relevant sediment-bound compounds. Furthermore, a compliance of effect concentrations derived from weatherfish embryos exposed to sediment extracts (96h-LC 50 ) with both measured gradient of sediment contamination and previously published results was observed. In comparison to zebrafish, weatherfish embryos showed higher sensitivity to the bioavailability-mimicking extracts from PHWE but lower sensitivity to extracts gained with acetone. SCAs conducted with weatherfish embryos revealed practical difficulties that prevented an implementation with three of four sediments tested. In summary, an application of weatherfish embryos, using bioassays with sediment extracts from PHWE might increase the ecological relevance of sediment toxicity testing: it allows investigations using benthic and temperate fish species considering both bioavailable contaminants and animal welfare

Field Validation of Toxicity Tests to Evaluate the Potential for Beneficial Use of Produced Water

Energy Technology Data Exchange (ETDEWEB)

Joseph Bidwell; Jonathan Fisher; Naomi Cooper

2008-03-31

This study investigated potential biological effects of produced water contamination derived from occasional surface overflow and possible subsurface intrusion at an oil production site along the shore of Skiatook Lake, Oklahoma. We monitored basic chemistry and acute toxicity to a suite of standard aquatic test species (fathead minnow-Pimephales promelas, Daphnia pulex, Daphnia magna, and Ceriodaphnia dubia) in produced water and in samples taken from shallow groundwater wells on the site. Toxicity identification evaluations and ion toxicity modeling were used to identify toxic constituents in the samples. Lake sediment at the oil production site and at a reference site were also analyzed for brine intrusion chemically and by testing sediment toxicity using the benthic invertebrates, Chironomus dilutus, and Hyallela azteca. Sediment quality was also assessed with in situ survival and growth studies with H. azteca and the Asian clam, Corbicula fluminea, and by benthic macroinvertebrate community sampling. The produced water was acutely toxic to the aquatic test organisms at concentrations ranging from 1% to 10% of the whole produced water sample. Toxicity identification evaluation and ion toxicity modeling indicated major ion salts and hydrocarbons were the primary mixture toxicants. The standardized test species used in the laboratory bioassays exhibited differences in sensitivity to these two general classes of contaminants, which underscores the importance of using multiple species when evaluating produced water toxicity. Toxicity of groundwater was greater in samples from wells near a produced water injection well and an evaporation pond. Principle component analyses (PCA) of chemical data derived from the groundwater wells indicated dilution by lake water and possible biogeochemical reactions as factors that ameliorated groundwater toxicity. Elevated concentrations of major ions were found in pore water from lake sediments, but toxicity from these ions was

Assessment of chemical and biological significance of arsenical species in the Maurice River drainage basin (N. J. ). Part I. Distribution in water and river and lake sediments

Energy Technology Data Exchange (ETDEWEB)

Faust, S.D.; Winka, A.J.; Belton, T.

1987-01-01

Levels of arsenic were determined in the bottom sediments and waters of the Maurice River, Blackwater Branch, and Union Lake, (N.J.) that were contaminated by a local chemical industry. This was the only known source of the arsenic. Levels of total arsenic in the sediments and waters were determined quarterly over the course of one year. Sediments were extracted for water soluble and total extractable arsenic fractions and partitioned into four species: monomethylarsonic acid (MMAA), dimethylarsinic acid (DMAA), arsenite (As(III)), and arsenate (As(V)). In Union Lake at a shallow sandy sediment site, As (V) predominates. In organic sediments, As (III) or (V) predominate depending upon the dissolved oxygen content of the overlying waters. The oxidations state of the arsenic was affected also by the seasonal lake cycles of stratifying or mixing.

Geno-toxicity assay of sediment and water samples from the Upper Silesia post-mining areas, Poland by means of Allium-test

Energy Technology Data Exchange (ETDEWEB)

Geras' kin, S.; Oudalova, A.; Michalik, B.; Dikareva, N.; Dikarev, V. [Russian Institute of Agricultural Radiology & Agroecology RAAS, Obninsk (Russian Federation)

2011-05-15

Genotoxic potential of two environmental compartments (water and sediment) from the Upper Silesia Coal Basin (USCB), Poland were evaluated and compared by employing root meristem cells of Allium cepa. The clear genotoxic effect of water and sediment sampled was shown, with an important contribution of severe types of cytogenetic abnormalities. The most biologically relevant pollutants were revealed through multivariate statistical analysis of relationships between biological effects registered and the environment contamination. Overall, results of simultaneous use of conventional monitoring methods and biological tests suggested that contemporary levels of persistent pollutants in post-mining areas of the USCB may enhance the risk both for human health and biological components of natural ecosystems.

Studies of trace metals in fish, sediment and water from kpong reservior

International Nuclear Information System (INIS)

Yikpo, Wisdom Kwasi

2014-06-01

Water of good quality is indispensable to human survival on earth. The provision of potable water to both the rural and the urban populations is necessary to prevent health hazards. The aim of this research was to assess water quality with respect to physicochemical parameters and trace metals levels in the water, the sediment and the fish species from the Kpong Reservoir on the Lower Volta River. The water, the sediment and the fish samples were collected monthly for six (6) months from November 2011 to February 2012 (dry season) and from May to July 2012 ( wet season). The water, the sediment and the fish samples were analyzed for Hg, Se, Fe, Mn and Pb using Atomic Absorption spectroscopy (AAS). Mercury was determined using a cold vapour technique with the AAS equipped with a hydride generator. Selenium was also determined by hydride generation. A mixture of nitric acid (HNO3 65%), hydrochloric acid ( HCl 35%) and hydrogen peroxide (H2O2 30%) was used for complete oxidation of the organic sample in a fume chamber. The samples were loaded on a Milestone microwave Labstation ETHOS 900, INSTR:MLS -1200 MEGA. The results of this study showed that there were significant differences in concentrations of the physicochemical parameters between the two seasons. Domestic, municipal and Agricultural waste might have contributed to the release of higher contaminants into the sediment in both seasons. Coefficients of variation for the physicochemical parameters were below 50%, while iron and lead in addition to phosphate and sulphate were more than 50%. The mean concentration of trace metals in the water were 0.008 mg/L for Hg, 0.0035 mg/L for Se, 0.255 mg/L for Fe, 0.087 mg/L for Mn and 0.135 mg/L for Pb. Levels of all trace metals were below the WHO guideline values, except Pb which exceeded at 0.05 mg/L. Levels of nutrients were also below the WHO guideline value except phosphate which recorded a standard deviation of ±0.02 for the WHO guideline value of 0.3 mg/ L. The

Sediment type affects competition between a native and an exotic species in coastal China.

Science.gov (United States)

Li, Hong-Li; Wang, Yong-Yang; An, Shu-Qing; Zhi, Ying-Biao; Lei, Guang-Chun; Zhang, Ming-Xiang

2014-10-23

Different types of sediments in salt marsh have different physical and chemical characters. Thus sediment type plays a role in plant competition and growth in salt marsh ecosystems. Spartina anglica populations have been increasingly confined to upper elevation gradients of clay, and the niche sediment has changed. Because the niches of S. anglica and the native species Scirpus triqueter overlap, we conducted a greenhouse experiment to test the hypothesis that plant competition has changed under different types of sediments. Biomass and asexual reproduction were analyzed, and inter- and intraspecific competition was measured by log response ratio for the two species in both monoculture and combination under three sediment types (sand, clay and mixture of sand and clay). For S. anglica, biomass, ramet number and rhizome length in combination declined significantly compared with those in monoculture, and the intensity of interspecific competition was significantly higher than that of intraspecific competition under all sediments. For S. triqueter, the intensities of intra- and interspecific competition were not significantly different. This indicates that S. triqueter exerts an asymmetric competitive advantage over S. anglica across all sediments, but especially clay. Thus the sediment type changes competition between S. anglica and S. triqueter.

Toxicity of water and sediment from stormwater retarding basins to Hydra hexactinella

DEFF Research Database (Denmark)

Rosenkrantz, Rikke Tjørnhøj; Pollino, Carmel A.; Nugegoda, Dayanthi

2008-01-01

of 50 ml/L and 100 ml/L, while the 7 h pulse exposure caused a significant increase in the mean population growth rate compared to the control. Water samples from the two other retarding basins were found non-toxic to H. hexactinella. This is the first study to employ sediment tests with Hydra spp....... on stormwater sediments and a lower population growth rate was observed for organisms exposed to sediment from the Avoca St retarding basins. The behavioral study showed that H. hexactinella tended to avoid the sediment-water interface when exposed to sediment from all retarding basins, compared...... to the reference sediment. Further work is needed to determine the long-term effects of stormwater polluted sediments and acute effects due to organism exposure to short-term high concentrations during rain events. (C) 2008 Elsevier Ltd. All rights reserved....

Opportunistic Pathogens and Microbial Communities and Their Associations with Sediment Physical Parameters in Drinking Water Storage Tank Sediments

Science.gov (United States)

Qin, Ke; Struewing, Ian; Domingo, Jorge Santo; Lytle, Darren

2017-01-01

The occurrence and densities of opportunistic pathogens (OPs), the microbial community structure, and their associations with sediment elements from eight water storage tanks in Ohio, West Virginia, and Texas were investigated. The elemental composition of sediments was measured through X-ray fluorescence (XRF) spectra. The occurrence and densities of OPs and amoeba hosts (i.e., Legionella spp. and L. pneumophila, Mycobacterium spp., P. aeruginosa, V. vermiformis, Acanthamoeba spp.) were determined using genus- or species-specific qPCR assays. Microbial community analysis was performed using next generation sequencing on the Illumina Miseq platform. Mycobacterium spp. were most frequently detected in the sediments and water samples (88% and 88%), followed by Legionella spp. (50% and 50%), Acanthamoeba spp. (63% and 13%), V. vermiformis (50% and 25%), and P. aeruginosa (0 and 50%) by qPCR method. Comamonadaceae (22.8%), Sphingomonadaceae (10.3%), and Oxalobacteraceae (10.1%) were the most dominant families by sequencing method. Microbial communities in water samples were mostly separated with those in sediment samples, suggesting differences of communities between two matrices even in the same location. There were associations of OPs with microbial communities. Both OPs and microbial community structures were positively associated with some elements (Al and K) in sediments mainly from pipe material corrosions. Opportunistic pathogens presented in both water and sediments, and the latter could act as a reservoir of microbial contamination. There appears to be an association between potential opportunistic pathogens and microbial community structures. These microbial communities may be influenced by constituents within storage tank sediments. The results imply that compositions of microbial community and elements may influence and indicate microbial water quality and pipeline corrosion, and that these constituents may be important for optimal storage tank management

Testing the behaviour of different kinetic models for uptake/release of radionuclides between water and sediments when implemented in a marine dispersion model

International Nuclear Information System (INIS)

Perianez, R.

2004-01-01

Three kinetic models for adsorption/release of 137 Cs between water and sediments have been tested when they are included in a previously validated dispersion model of the English Channel. Radionuclides are released to the Channel from La Hague nuclear fuel reprocessing plant (France). The kinetic models are a 1-step model consisting of a single reversible reaction, a 2-step model consisting of two consecutive reversible reactions and an irreversible model consisting of three parallel reactions: two reversible and one irreversible. The models have been tested under three typical situations that correspond to the source terms that can generally be found: instantaneous release, continuous release and redissolution of radionuclides from contaminated sediments. Differences between the models become more evident when contact times between water and sediments are larger (continuous release) and in the case of redissolution from sediments. Time scales for the redissolution process are rather different between the three models. The 1-step model produces a redissolution that is too fast when compared with experimental evidence. The irreversible model requires that saturation effects of the irreversible phase are included. Probably, the 2-step model represents the best compromise between ease and level of detail of the description of sorption/release processes

Origin of preferential clay particle orientation in faults, and relationships with pore-water flow and water-sediment interactions. Two natural examples

International Nuclear Information System (INIS)

Labaume, P.

1998-01-01

Two natural examples are presented of shear deformation associated with thrust faulting in clayey sediments. The first example is the basal decollement fault of the Barbados accretionary prism (Lesser Antilles), drilled during ODP Leg 156. This decollement is an active fault where the relationships between pore-water and deformation can be studied in situ. The second example is the Eocene south-Pyrenean basin (northern Spain), studied by the European Community EBRO Network Working Group. In this case, fluid activity in fossil thrust-faults was studied indirectly through the products of water-sediment interactions. (author)

Water-level fluctuations influence sediment porewater ...

Science.gov (United States)

Reservoirs typically have elevated fish mercury (Hg) levels compared to natural lakes and rivers. A unique feature of reservoirs is water-level management which can result in sediment exposure to the air. The objective of this study is to identify how reservoir water-level fluctuations impact Hg cycling, particularly the formation of the more toxic and bioaccumulative methylmercury (MeHg). Total-Hg (THg), MeHg, stable isotope methylation rates and several ancillary parameters were measured in reservoir sediments (including some in porewater and overlying water) that are seasonally and permanently inundated. The results showed that sediment and porewater MeHg concentrations were over 3-times higher in areas experiencing water-level fluctuations compared to permanently inundated sediments. Analysis of the data suggest that the enhanced breakdown of organic matter in sediments experiencing water-level fluctuations has a two-fold effect on stimulating Hg methylation: 1) it increases the partitioning of inorganic Hg from the solid phase into the porewater phase (lower log Kd values) where it is more bioavailable for methylation; and 2) it increases dissolved organic carbon (DOC) in the porewater which can stimulate the microbial community that can methylate Hg. Sulfate concentrations and cycling were enhanced in the seasonally inundated sediments and may have also contributed to increased MeHg production. Overall, our results suggest that reservoir management a

Origin and biogeography of the deep-water Mediterranean Hydromedusae including the description of two new species collected in submarine canyons of Northwestern Mediterranean

Directory of Open Access Journals (Sweden)

J. M. Gili

1998-06-01

Full Text Available Two new species of hydromedusae (Foersteria antoniae and Cunina simplex are described from plankton collected in sediment traps placed in the Lacaze-Duthiers Submarine Canyon and along Banyuls-sur-Mer coast (northwestern Mediterranean. The Mediterranean hydromedusan deep-water fauna contains 41 species which represent 45.5 % of the world-wide deep-sea hydromedusae fauna (90 and 20% of the total number of Mediterranean hydromedusae (204. The Mediterranean deep-water hydromedusan fauna is characterised by a large percentage of holoplanktonic species (61%, mainly Trachymedusae. Nevertheless, contrary to the general opinion, the percentage of meroplanktonic species is equally high. The most original features of this fauna lies however in the importance of the number of endemic species (22% and in the fact that the majority of them are meroplanktonic Leptomedusae with a supposed bathybenthic stage. Some of the endemic species could still represent relics of the primitive Tethys fauna having survived to the Messinian crisis. The origin of the Mediterranean deep-water hydromedusan fauna is discussed and a general hypothesis is proposed.

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

Directory of Open Access Journals (Sweden)

Kristi S Shaw

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

Effects of linuron on a rooted aquatic macrophyte in sediment-dosed test systems

NARCIS (Netherlands)

Buresova, H.; Crum, S.J.H.; Belgers, J.D.M.; Adriaanse, P.I.; Arts, G.H.P.

2013-01-01

Effects of linuron on the sediment-rooted aquatic macrophyte Myriophyllum spicatum L. were studied in sediment-dosed test systems following a proposed guideline with extended test duration. Sediment, pore water, overlying water and macrophyte shoots were sampled weekly for chemical analyses. Linuron

Neutron activation analysis studies of marine biological species and related marine sediments

International Nuclear Information System (INIS)

Guinn, V.P.; Di Casa, M.; de Goeij, J.J.M.; Young, D.R.

1974-01-01

To assess the effects, if any, of elemental pollution of the Pacific Ocean from the major Southern California sewage outfalls, samples of ocean sediments were obtained and specimens of Dover Sole were caught in a number of locations. Liver tissue samples from Dover Sole specimens were analyzed for 12 elements and sediment samples for 4 elements. Although a number of the elements were highly concentrated in the surface sediments in the heavily-polluted areas, the Dover Sole showed no evidence of picking up any of the 12 elements from these polluted sediments. Sediment profiles, versus depth, (0-34 cm) were also determined for As, Sb, Se, and Hg. Stemming partly from the results of the NSF Baseline Study, the Southern California Coastal Water Research Project (SCCWRP) became interested in a more intensive multi-element study of marine biological species and ocean sediments off the coast of Southern California. The purpose of this study was to assess the effects, if any, of a number of selected elements of interest being discharged into the Pacific Ocean from the principal sewage outfalls in the Southern California (Los Angeles) area upon marine biological species. The 12 elements selected for study were Cr, Fe, Co, Cu, Zn, As, Se, Mo, Ag, Cd, Sb, and Hg. Since a number of these elements were not amenable to purely instrumental NAA measurements, a suitable post-irradiation radiochemical separation procedure was devised, thoroughly tested, and then applied to 39 samples of liver tissue from specimens of Dover Sole caught in non-polluted, slightly-polluted, fairly-polluted, and heavily-polluted areas along the coast. A number of surface sediment samples from these same locations were also analyzed, by both instrumental and radiochemical NAA. In the following sections, the samples analyzed are cited, the procedures developed and employed are described, the results obtained are presented, and the conclusions reached are discussed

Biodegradation of sulfamethoxazole photo-transformation products in a water/sediment test.

Science.gov (United States)

Su, Tong; Deng, Huiping; Benskin, Jonathan P; Radke, Michael

2016-04-01

Occurrence of the antibiotic sulfamethoxazole (SMX) in the aquatic environment is of concern due to its potential to induce antibiotic resistance in pathogenic bacteria. While degradation of SMX can occur by numerous processes, the environmental fate of its transformation products (TPs) remains poorly understood. In the present work, biodegradation of SMX photo-TPs was investigated in a water/sediment system. Photo-TPs were produced by exposing SMX to artificial sunlight for 48 h. The resulting mixture of 8 photo-TPs was characterized using a combination of ultra-high performance liquid chromatography coupled to high-resolution mass spectrometry and tandem mass spectrometry, and then used in biodegradation experiments. Significant differences in transformation among SMX photo-TPs were observed in the water/sediment system, with four photo-TPs displaying evidence of biodegradation (dissipation half-lives [DT50] of 39.7 d for 3-amino-5-methylisoxazole, 12.7 d for 4-nitro-sulfamethxoazole, 7.6 d for an SMX isomer and 2.4 d for [C10H13N3O4S]), two displaying primarily abiotic degradation (DT50 of 31 d for sulfanilic acid and 74.9 d for 5-methylisoxazol-3-yl-sulfamate), and two photo-TPs behaving largely recalcitrantly. Remarkably, TPs previously reported to be photo-stable also were persistent in biodegradation experiments. The most surprising observation was an increase in SMX concentrations when the irradiated solution was incubated, which we attribute to back-transformation of certain photo-TPs by sediment bacteria (85% from 4-nitro-sulfamethoxazole). This process could contribute to exposure to SMX in the aquatic environment that is higher than one would expect based on the fate of SMX alone. The results highlight the importance of considering TPs along with their parent compounds when characterizing environmental risks of emerging contaminants. Copyright © 2016 Elsevier Ltd. All rights reserved.

Evaluation of water column and sediment toxicity from an abandoned uranium mine using a battery of bioassays

International Nuclear Information System (INIS)

Antunes, S.C.; Figueiredo, D.R. de; Marques, S.M.; Castro, B.B.; Pereira, R.; Goncalves, F.

2007-01-01

Uranium mining activities in Cunha Baixa, Mangualde (Portugal), were extensive between 1967 and 1993, with high production of poor ore. Ore exploitation left millions of tons of tailings in the surrounding area, close to human houses. Contamination of the area (water and soil compartment) presently represents a serious hazard to humans and wildlife. The aim of this work was to evaluate the acute toxicity of water and sediments from a pond that floods a uranium mine pit, in two periods (spring and autumn). High contents of metals were found in water samples (chiefly Mn, Fe, Al, U, Sr). A battery of assays was applied to screen the acute toxicity of the different compartments using algae, crustaceans and dipterans. Results showed that the sediments were non-toxic, unlike the superficial water. Water toxicity was higher in the autumn, when the effluent was more acidic, compared to spring. In the water toxicity assays, the relative sensitivity of the test species used was Daphnia longispina > Pseudokirchneriella subcapitata > Daphnia magna. The present study is part of the chemical and ecotoxicological characterisation of the aquatic compartment performed in the Tier 1 of the Ecological Risk Assessment of the Cunha Baixa mining area

Sediment pore water distribution coefficients of PCB congeners in enriched black carbon sediment

International Nuclear Information System (INIS)

Martinez, Andres; O'Sullivan, Colin; Reible, Danny; Hornbuckle, Keri C.

2013-01-01

More than 2300 sediment pore water distribution coefficients (K PCBids ) of 93 polychlorinated biphenyls (PCBs) were measured and modeled from sediments from Indiana Harbor and Ship Canal. K PCBids were calculated from previously reported bulk sediment values and newly analyzed pore water. PCBs in pore waters were measured using SPME PDMS-fiber and ∑PCB ranged from 41 to 1500 ng L −1 . The resulting K PCBids were ∼1 log unit lower in comparison to other reported values. A simple model for the K PCBid consisted of the product of the organic carbon fraction and the octanol–water partition coefficient and provided an excellent prediction for the measured values, with a mean square error of 0.09 ± 0.06. Although black carbon content is very high in these sediments and was expected to play an important role in the distribution of PCBs, no improvement was obtained when a two-carbon model was used. -- Highlights: •PCB sediment-pore water distribution coefficients were measured and modeled. •Distribution coefficients were lower in comparison to other reported values. •Organic carbon fraction times the K OW yielded the best prediction model. •The incorporation of black carbon into a model did not improve the results. -- The organic carbon fraction times the octanol–water partition coefficient yielded the best prediction model for the sediment pore water distribution coefficient of PCBs

Toxicity of sediments potentially contaminated by coal mining and natural gas extraction to unionid mussels and commonly tested benthic invertebrates

Science.gov (United States)

Wang, Ning; Ingersoll, Christopher G.; Kunz, James L.; Brumbaugh, William G.; Kane, Cindy M.; Evans, R. Brian; Alexander, Steven; Walker, Craig; Bakaletz, Steve

2013-01-01

Sediment toxicity tests were conducted to assess potential effects of contaminants associated with coal mining or natural gas extraction activities in the upper Tennessee River basin and eastern Cumberland River basin in the United States. Test species included two unionid mussels (rainbow mussel, Villosa iris, and wavy-rayed lampmussel, Lampsilis fasciola, 28-d exposures), and the commonly tested amphipod, Hyalella azteca (28-d exposure) and midge, Chironomus dilutus (10-d exposure). Sediments were collected from seven test sites with mussel communities classified as impacted and in proximity to coal mining or gas extraction activities, and from five reference sites with mussel communities classified as not impacted and no or limited coal mining or gas extraction activities. Additional samples were collected from six test sites potentially with high concentrations of polycyclic aromatic hydrocarbons (PAHs) and from a test site contaminated by a coal ash spill. Mean survival, length, or biomass of one or more test species was reduced in 10 of 14 test samples (71%) from impacted areas relative to the response of organisms in the five reference samples. A higher proportion of samples was classified as toxic to mussels (63% for rainbow mussels, 50% for wavy-rayed lampmussels) compared with amphipods (38%) or midge (38%). Concentrations of total recoverable metals and total PAHs in sediments did not exceed effects-based probable effect concentrations (PECs). However, the survival, length, or biomasses of the mussels were reduced significantly with increasing PEC quotients for metals and for total PAHs, or with increasing sum equilibrium-partitioning sediment benchmark toxic units for PAHs. The growth of the rainbow mussel also significantly decreased with increasing concentrations of a major anion (chloride) and major cations (calcium and magnesium) in sediment pore water. Results of the present study indicated that (1) the findings from laboratory tests were generally

Effects of Feeding Strategy, Sediment Characteristics, and Chemical Properties on Polychlorinated Biphenyl and Polybrominated Diphenyl Ether Bioaccumulation from Marine Sediments in Two Invertebrates.

Science.gov (United States)

Frouin, H; Jackman, P; Dangerfield, N D; Ross, P S

2017-08-01

Shellfish and sediment invertebrates have been widely used to assess pollution trends over space and time in coastal environments around the world. However, few studies have compared the bioaccumulation potential of different test species over a range of sediment-contaminant concentrations and profiles. The bioavailability of sediment-related contaminants was evaluated using sediments collected from sites (n = 12) throughout the Salish Sea, British Columbia, Canada. Two benthic marine invertebrates-the Baltic clam Macoma balthica and the polychaete worm Neanthes arenaceodentata-were exposed for 28 days in a controlled environment to these field-collected coastal sediments. The congener-specific uptake of legacy polychlorinated biphenyls (PCBs) and emergent polybrominated diphenyl ethers (PBDEs) was determined using high-resolution gas chromatography/mass spectrometry in sediments and in invertebrates after the experimental exposure. The polychaete Neanthes accumulated lower concentrations of PCBs but higher concentrations of PBDEs. The present study indicates that differences in bioaccumulation between these two invertebrates shape the accumulation of PCB and PBDE congeners, reflect differences in feeding strategies, and reveal the physicochemical properties of the contaminants and sediment properties. Because biota-sediment accumulation factor values are often calculated for environmental monitoring or site-specific impact assessments, our results provide insight into potentially confounding factors and the need for caution when selecting indicator species for coastal marine pollution.

Benthic solute exchange and carbon mineralization in two shallow subtidal sandy sediments: Effect of advective pore-water exchange

DEFF Research Database (Denmark)

Cook, Perran L. M.; Wenzhofer, Frank; Glud, Ronnie N.

2007-01-01

within the range measured in the chambers. The contribution of advection to solute exchange was highly variable and dependent on sediment topography. Advective processes also had a pronounced influence on the in situ distribution of O-2 within the sediment, with characteristic two-dimensional patterns...... of O-2 distribution across ripples, and also deep subsurface O-2 pools, being observed. Mineralization pathways were predominantly aerobic when benthic mineralization rates were low and advective pore-water flow high as a result of well-developed sediment topography. By contrast, mineralization...... proceeded predominantly through sulfate reduction when benthic mineralization rates were high and advective pore-water flow low as a result of poorly developed topography. Previous studies of benthic mineralization in shallow sandy sediments have generally ignored these dynamics and, hence, have overlooked...

Migration of trace heavy metals at the sea water/sediment interface

International Nuclear Information System (INIS)

Terada, Kikuo; Tomiyama, Chisato

1984-01-01

Migration behavior of some trace heavy metals such as Co(II), Cu(II), Mn(II) and Zn(II) at the sea water/sediment interface was investigated by tank experiments. The sea water which was doped with these metal ions (ppb to ppm levels) allowed to contact with the raw-, ignited- and autoclaved-marine sediments and the change of the concentration of each metal was traced at definite time intervals. At the end of the experiments, a core sample of the sediment was taken and analyzed for each metal in every 1 mm thick segment. On the other hand, the surface sediment was submitted to partial extraction with various kinds of reagents to estimate the chemical species of the metals captured in the sediment. While every metal ion was quickly adsorbed on surface of the raw sediment, a concentration gradient from surface to bottom of the water phase occurred in the ignited sediment system. The migration of manganese to the sediment phase was assumed to be concerned with bacterial activity in the sediment. Copper and zinc seemed to be adsorbed very quickly onto some fine sediment particles by the formation of organometallic complexes with some organic materials existing in the sediments. Cobalt migrated relatively fast downward within the sediment phase after its deposition. (author)

Reconnaissance On Chi-Square Test Procedure For Determining Two Species Association

Science.gov (United States)

Marisa, Hanifa

2008-01-01

Determining the assosiation of two species by using chi-square test has been published. Utility of this procedure to plants species at certain location, shows that the procedure could not find "ecologically" association. Tens sampling units have been made to record some weeds species in Indralaya, South Sumatera. Chi square test; Xt2 = N[|(ad)-(bc)|-(N/2)]2/mnrs (Eq:1) on two species (Cleome sp and Eleusine indica) of the weeds shows positive assosiation; while ecologically in nature, there is no relationship between them. Some alternatives are proposed to this problem; simplified chi-square test steps, make further study to find out ecologically association, or at last, ignore it.

Studying Suspended Sediment Mechanism with Two-Phase PIV

Science.gov (United States)

Matinpour, H.; Atkinson, J. F.; Bennett, S. J.; Guala, M.

2017-12-01

Suspended sediment transport affects soil erosion, agriculture and water resources quality. Turbulent diffusion is the most primary force to maintain sediments in suspension. Although extensive previous literature have been studying the interactions between turbulent motion and suspended sediment, mechanism of sediments in suspension is still poorly understood. In this study, we investigate suspension of sediments as two distinct phases: one phase of sediments and another phase of fluid with turbulent motions. We designed and deployed a state-of-the-art two-phase PIV measurement technique to discriminate these two phases and acquire velocities of each phase separately and simultaneously. The technique that we have developed is employing a computer-vision based method, which enables us to discriminate sediment particles from fluid tracer particles based on two thresholds, dissimilar particle sizes and different particle intensities. Results indicate that fluid turbulence decreases in the presence of suspended sediments. Obtaining only sediment phase consecutive images enable us to compute fluctuation sediment concentration. This result enlightens understanding of complex interaction between the fluctuation velocities and the fluctuation of associated mass and compares turbulent viscosity with turbulent eddy diffusivity experimentally.

Investigations into the differential reactivity of endogenous and exogenous mercury species in coastal sediments.

Science.gov (United States)

Bouchet, S; Rodriguez-Gonzalez, P; Bridou, R; Monperrus, M; Tessier, E; Anschutz, P; Guyoneaud, R; Amouroux, D

2013-03-01

Stable isotopic tracer methodologies now allow the evaluation of the reactivity of the endogenous (ambient) and exogenous (added) Hg to further predict the potential effect of Hg inputs in ecosystems. The differential reactivity of endogenous and exogenous Hg was compared in superficial sediments collected in a coastal lagoon (Arcachon Bay) and in an estuary (Adour River) from the Bay of Biscay (SW France). All Hg species (gaseous, aqueous, and solid fraction) and ancillary data were measured during time course slurry experiments under variable redox conditions. The average endogenous methylation yield was higher in the estuarine (1.2 %) than in the lagoonal sediment (0.5 %), although both methylation and demethylation rates were higher in the lagoonal sediment in relation with a higher sulfate-reducing activity. Demethylation was overall more consistent than methylation in both sediments. The endogenous and exogenous Hg behaviors were always correlated but the exogenous inorganic Hg (IHg) partitioning into water was 2.0-4.3 times higher than the endogenous one. Its methylation was just slightly higher (1.4) in the estuarine sediment while the difference in the lagoonal sediment was much larger (3.6). The relative endogenous and exogenous methylation yields were not correlated to IHg partitioning, demonstrating that the bioavailable species distributions were different for the two IHg pools. In both sediments, the exogenous IHg partitioning equaled the endogenous one within a week, while its higher methylation lasted for months. Such results provide an original assessment approach to compare coastal sediment response to Hg inputs.

Multi-Elements in Waters and Sediments of Shallow Lakes: Relationships with Water, Sediment, and Watershed Characteristics.

Science.gov (United States)

Kissoon, La Toya T; Jacob, Donna L; Hanson, Mark A; Herwig, Brian R; Bowe, Shane E; Otte, Marinus L

2015-06-01

We measured concentrations of multiple elements, including rare earth elements, in waters and sediments of 38 shallow lakes of varying turbidity and macrophyte cover in the Prairie Parkland (PP) and Laurentian Mixed Forest (LMF) provinces of Minnesota. PP shallow lakes had higher element concentrations in waters and sediments compared to LMF sites. Redundancy analysis indicated that a combination of site- and watershed-scale features explained a large proportion of among-lake variability in element concentrations in lake water and sediments. Percent woodland cover in watersheds, turbidity, open water area, and macrophyte cover collectively explained 65.2 % of variation in element concentrations in lake waters. Sediment fraction smaller than 63 µm, percent woodland in watersheds, open water area, and sediment organic matter collectively explained 64.2 % of variation in element concentrations in lake sediments. In contrast to earlier work on shallow lakes, our results showed the extent to which multiple elements in shallow lake waters and sediments were influenced by a combination of variables including sediment characteristics, lake morphology, and percent land cover in watersheds. These results are informative because they help illustrate the extent of functional connectivity between shallow lakes and adjacent lands within these lake watersheds.

Geochemical control on the reduction of U(VI) to mononuclear U(IV) species in lacustrine sediments

Science.gov (United States)

Stetten, L.; Mangeret, A.; Brest, J.; Seder-Colomina, M.; Le Pape, P.; Ikogou, M.; Zeyen, N.; Thouvenot, A.; Julien, A.; Alcalde, G.; Reyss, J. L.; Bombled, B.; Rabouille, C.; Olivi, L.; Proux, O.; Cazala, C.; Morin, G.

2018-02-01

Contaminated systems in which uranium (U) concentrations slightly exceed the geochemical background are of particular interest to identify natural processes governing U trapping and accumulation in Earth's surface environments. For this purpose, we examined the role of early diagenesis on the evolution of U speciation and mobility in sediments from an artificial lake located downstream from a former mining site. Sediment and pore water chemistry together with U and Fe solid state speciation were analyzed in sediment cores sampled down to 50 cm depth at four locations in the lake. These organic-rich sediments (∼12% organic C) exhibited U concentrations in the 40-80 mg kg-1 range. The sediment columns were anoxic 2-3 mm below the sediment-water interface and pore waters pH was circumneutral. Pore water chemistry profiles showed that organic carbon mineralization was associated with Fe and Mn reduction and was correlated with a decrease in dissolved U concentration with depth. Immobilization of U in the sediment was correlated with the reduction of U(VI) to U(IV) at depth, as shown by U LIII-edge XANES spectroscopic analysis. XANES and EXAFS spectroscopy at the Fe K-edge showed the reduction of structural Fe(III) to Fe(II) in phyllosilicate minerals with depth, coincident with U(VI) to U(IV) reduction. Thermodynamic modeling suggests that Fe(II) could act as a major reducing agent for U(VI) during early diagenesis of these sediments, leading to complete U reduction below ∼30 cm depth. Shell-by-shell and Cauchy-Wavelet analysis of U LIII-EXAFS spectra indicates that U(VI) and U(IV) are mainly present as mononuclear species bound to C, P or Si ligands. Chemical extractions confirmed that ∼60-80% of U was present as non-crystalline species, which emphasizes that such species should be considered when evaluating the fate of U in lacustrine environments and the efficiency of sediment remediation strategies.

Performance testing of the sediment-contaminant transport model, SERATRA, at different rivers

International Nuclear Information System (INIS)

Onishi, Y.; Yabusaki, S.B.; Kincaid, C.T.

1982-04-01

Mathematical models of sediment-contaminant migration in surface water must account for transport, intermedia transfer, decay and degradation, and transformation processes. The unsteady, two dimensional, sediment-contaminant transport code, SERATRA (Onishi, Schreiber and Codell 1980) includes these mechanisms. To assess the accuracy of SERATRA to simulate the sediment-contaminant transport and fate processes, the code was tested against one-dimensional analytical solutions, checked for its mass balance, and applied to field sites. The field application cases ranged from relatively simple, steady conditions to unsteady, nonuniform conditions for large, intermediate, and small rivers. It was found that SERATRA is capable of simulating sediment-contaminant transport under a wide range of conditions

Habitat selection by two species of burrowing mayfly nymphs in the Les Cheneaux Islands region of northern Lake Huron

Science.gov (United States)

Blouin, Marc A.; Hudson, Patrick; Chriscinske, Margret

2004-01-01

This study focused primarily on the habitat preferences of Hexagenia limbata andEphemera simulans, two species prevalent in northern Lake Huron, to gain a better understanding of the key components that determined their distribution and abundance. Both species preferred habitats based upon depth and sediment type. In addition, the burrowing activity of H. limbata was examined using in-situ, underwater sampling techniques specifically designed for the study. SCUBA divers made resin casts and took clear sediment cores in order to study how the burrow densities of H. limbata related to the sediment: water volume ratios. H. limbata contributed to the bioturbation and sediment porosity in specific, fine-sediment habitats. Younger age classes of this species utilized the burrows of their larger cohorts, an adaptation that could allow for energy savings and optimized growth.

Comparison of Mercury in Water, Bottom Sediment, and Zooplankton in Two Front Range Reservoirs in Colorado, 2008-09

Science.gov (United States)

Mast, M. Alisa; Krabbenhoft, David P.

2010-01-01

The U.S. Geological Survey, in cooperation with the Colorado Department of Public Health and Environment, conducted a study to investigate environmental factors that may contribute to the bioaccumulation of mercury in two Front Range reservoirs. One of the reservoirs, Brush Hollow Reservoir, currently (2009) has a fish-consumption advisory for mercury in walleye (Stizostedion vitreum), and the other, Pueblo Reservoir, which is nearby, does not. Water, bottom sediment, and zooplankton samples were collected during 2008 and 2009, and a sediment-incubation experiment was conducted in 2009. Total mercury concentrations were low in midlake water samples and were not substantially different between the two reservoirs. The only water samples with detectable methylmercury were collected in shallow areas of Brush Hollow Reservoir during spring. Mercury concentrations in reservoir bottom sediments were similar to those reported for stream sediments from unmined basins across the United States. Despite higher concentrations of fish-tissue mercury in Brush Hollow Reservoir, concentrations of methylmercury in sediment were as much as 3 times higher in Pueblo Reservoir. Mercury concentrations in zooplankton were at the low end of concentrations reported for temperate lakes in the Northeastern United States and were similar between sites, which may reflect the seasonal timing of sampling. Factors affecting bioaccumulation of mercury were assessed, including mercury sources, water quality, and reservoir characteristics. Atmospheric deposition was determined to be the dominant source of mercury; however, due to the proximity of the reservoirs, atmospheric inputs likely are similar in both study areas. Water-quality constituents commonly associated with elevated concentrations of mercury in fish (pH, alkalinity, sulfate, nutrients, and dissolved organic carbon) did not appear to explain differences in fish-tissue mercury concentrations between the reservoirs. Low methylmercury

Organochlorine Pesticides (OCPs) in Sediment and Fish of Two Tropical Water Bodies Under Different Land Use.

Science.gov (United States)

Hinojosa-Garro, Demián; Burgos Chan, Adriana M; Rendón-von Osten, Jaime

2016-07-01

In this study we quantified and compared bioaccumulated OCPs in target fish species Cichlasoma urophthalmus (Mayan cichlid) and Oreochromis niloticus (Nile tilapia) and sediment in two lentic systems neighboring areas with different land use (Xnoha = agricultural/Mocu = nature reserve). Fish at both sites showed the same number of pesticide compounds (17) while in sediment were 17 and 20, respectively. ∑chlordane concentrations were significantly higher in Xnoha in both fish and sediment (1.0 and 0.17 µg/g, respectively). Here higher concentrations of o,p'DDT were found in fish than in sediments, this was similarly demonstrated in Mocu but to a lesser extent. The proportion of endosulfan sulfate was lower in Xnoha (<20 %) than in Mocu (<50 %) compared to the original product. Detected concentrations of ∑DDT and chlordane exceed international permissible limits. Results indicate that OCPs were present in both aquatic systems regardless of the differences in land use.

Resistance of Two Mediterranean Cold-Water Coral Species to Low-pH Conditions

Directory of Open Access Journals (Sweden)

Juancho Movilla

2013-12-01

Full Text Available Deep-water ecosystems are characterized by relatively low carbonate concentration values and, due to ocean acidification (OA, these habitats might be among the first to be exposed to undersaturated conditions in the forthcoming years. However, until now, very few studies have been conducted to test how cold-water coral (CWC species react to such changes in the seawater chemistry. The present work aims to investigate the mid-term effect of decreased pH on calcification of the two branching CWC species most widely distributed in the Mediterranean, Lophelia pertusa and Madrepora oculata. No significant effects were observed in the skeletal growth rate, microdensity and porosity of both species after 6 months of exposure. However, while the calcification rate of M. oculata was similar for all colony fragments, a heterogeneous skeletal growth pattern was observed in L. pertusa, the younger nubbins showing higher growth rates than the older ones. A higher energy demand is expected in these young, fast-growing fragments and, therefore, a reduction in calcification might be noticed earlier during long-term exposure to acidified conditions.

Levels of potentially toxic metals in water, sediment and peat from Wonderfonteinspruit, North West Province, South Africa.

Science.gov (United States)

Nsaka, Ntumba C; McCrindle, Robert I; Ambushe, Abayneh A

2018-04-30

Environmental monitoring of the levels of potentially toxic metals is of importance because of possible adverse effects on living species. This study was conducted to assess the levels of Cd, Cr, Cu, Hg, Mn, Pb, U and V in water, sediment and peat samples collected from the region of Wonderfonteinspruit. Water samples were simply filtered and acidified with HNO 3 prior to analysis. Sediment and peat were oven-dried, ground, sieved and mineralised using a microwave digestion system. Concentrations of the selected elements in all samples were determined by inductively coupled plasma-mass spectrometry. A Zeeman mercury analyser was also used for quantification of Hg in the same sediment and peat samples. The method validation was carried out using SRM 1643e water and BCR 320R sediment certified reference materials. The results showed no significant difference at 95% level of confidence between the certified and measured values after using the Student's t-test. The levels of Cd, Cr, Cu, Pb, V and U found in rivers and dams were lower than the tentative South African water quality range guideline for domestic and irrigation purposes. However, water from dams and certain rivers was unsuitable for irrigation and domestic use.

Two specialized delayed-neutron detector designs for assays of fissionable elements in water and sediment samples

International Nuclear Information System (INIS)

Balestrini, S.J.; Balagna, J.P.; Menlove, H.O.

1976-01-01

Two specialized neutron-sensitive detectors are described which are employed for rapid assays of fissionable elements by sensing for delayed neutrons emitted by samples after they have been irradiated in a nuclear reactor. The more sensitive of the two detectors, designed to assay for uranium in water samples, is 40% efficient; the other, designed for sediment sample assays, is 27% efficient. These detectors are also designed to operate under water as an inexpensive shielding against neutron leakage from the reactor and neutrons from cosmic rays. (Auth.)

Sediment and toxic contaminant transport modeling in coastal waters

International Nuclear Information System (INIS)

Onishi, Y.; Mayer, D.W.; Argo, R.S.

1982-02-01

A hydrodynamic model, CAFE-I, a wave refraction model, LO3D, and a sediment and contaminant transport model, FETRA, were selected as tools for evaluating exposure levels of radionuclides, heavy metals, and other toxic chemicals in coastal waters. Prior to the application of these models to the Irish Sea and other coastal waters, the finite element model, FETRA, was tested to demonstrate its ability to simulate sediment and contaminant interactions (e.g., adsorption and desorption), and the mechanisms governing the transport, deposition, and resuspension of contaminated sediments

Nutrient fluxes across sediment-water interface in Bohai Bay Coastal Zone, China.

Science.gov (United States)

Mu, Di; Yuan, Dekui; Feng, Huan; Xing, Fangwei; Teo, Fang Yenn; Li, Shuangzhao

2017-01-30

Sediment cores and overlying water samples were collected at four sites in Tianjin Coastal Zone, Bohai Bay, to investigate nutrient (N, P and Si) exchanges across the sediment-water interface. The exchange fluxes of each nutrient species were estimated based on the porewater profiles and laboratory incubation experiments. The results showed significant differences between the two methods, which implied that molecular diffusion alone was not the dominant process controlling nutrient exchanges at these sites. The impacts of redox conditions and bioturbation on the nutrient fluxes were confirmed by the laboratory incubation experiments. The results from this study showed that the nutrient fluxes measured directly from the incubation experiment were more reliable than that predicted from the porewater profiles. The possible impacts causing variations in the nutrient fluxes include sewage discharge and land reclamation. Copyright © 2016 Elsevier Ltd. All rights reserved.

The Effects of Sediments Burdened by Sewerage Water Originating in Car Batteries Production in the Klenice River (CZ

Directory of Open Access Journals (Sweden)

Petra Beránková

2009-01-01

Full Text Available The aim of this work was to perform tests of genotoxicity and toxicity on samples of riverine sediments from a location subject to motor industry load (car battery production. Together with sediment samples we also collected benthos, biofilm and juvenile fish. Concentration of lead was established in all the samples since the sewage waters discharged from the car battery production plant are heavily polluted with lead. Genotoxicity was tested with two tests of genotoxicity: the SOS chromotest and the Escherichia coli WP2 test. The toxicity of sediments was tested with a test of toxicity performed on a water crustacean Daphnia magna. A profound toxic influence upon benthic organisms was found; a consequence of the river pollution with waste water and flush water from the car battery production plant. This toxic effect was also proven by an aqueous leach from the test performed with Daphnia magna. Both tests of genotoxicity proved a significant genotoxic potential of the sediment samples linked with the growth of the concentration of lead in the sediments (up to 647 mg kg-1. The content of lead also increased in the biofilm (up to 3.37 mg kg-1 of dry mass as well as in the fish bodies (up to 804.5 mg kg-1 of dry mass. This thesis is the first study of the load imposed on this river as a consequence of the waste water and flush water discharge from the motor industry production plant (car battery production.

Integrating the fish embryo toxicity test as triad element for sediment toxicity assessment based on the water framework directive approach

Energy Technology Data Exchange (ETDEWEB)

Bartzke, Mariana [Dept. Aquatic Ecotoxicology, Goethe Univ. Frankfurt am Main (Germany); Gobio GmbH, Aarbergen/Kettenbach (Germany); Dept. Bioanalytical Ecotoxicology, Helmholtz Centre for Environmental Research, UFZ, Leipzig (Germany); Delov, Vera [Dept. Aquatic Ecotoxicology, Goethe Univ. Frankfurt am Main (Germany); Gobio GmbH, Aarbergen/Kettenbach (Germany); Ecotoxicology, Fraunhofer Inst. for Molecular Biology and Applied Ecology IME, Aachen (Germany); Stahlschmidt-Allner, Petra; Allner, Bernhard [Gobio GmbH, Aarbergen/Kettenbach (Germany); Oehlmann, Joerg [Dept. Aquatic Ecotoxicology, Goethe Univ. Frankfurt am Main (Germany)

2010-04-15

Purpose: The objective of this study was to complement analyses according to the European Union Water Framework Directive (WFD) with a sediment toxicity analysis as part of an integrated river assessment. To this end, Hessian water courses were analyzed using the sediment quality triad concept according to Chapman with chemical analyses, in situ effect evaluations, and ecotoxicological assessments. For the ecotoxicological assessment (fish embryo toxicity test with Danio rerio), a new evaluation scheme was developed, the fish teratogenicity index (FTI), that allows for a classification of sediments into ecological quality classes compliant to the WFD. Materials and methods sediment and macrozoobenthos samples were taken from tributaries of the rivers Fulda and Lahn. Sediments were characterized regarding particle size, carbon, heavy metals, and polyaromatic hydrocarbon content. Macroinvertebrate samples were taken via multi-habitat sampling. The fish embryo toxicity test with D. rerio was conducted as a contact assay on the basis of DIN 38415-6. Results and discussion The integrated assessment indicated a significant influence of heavy metals and carbon content on macroinvertebrate communities. The bioaccessibility of sediment pollutants were clearly demonstrated by the FTI, which showed a wide range of adverse effects. A significant linear relationship between metals and the FTI was detected. However, there was no statistically significant evidence that macroinvertebrate communities were affected by the hydromorphological quality clements at the sampling sites. Conclusions The new scheme for the assessment of fish embryo toxicity test was successfully applied. The results suggest that sediment compounds impact macroinvertebrate communities and early development of fish. It demonstrates that the quality of sediments should be evaluated on a routine basis as part of an integrated river assessment. (orig.)

Development of a two-phase SPH model for sediment laden flows

Science.gov (United States)

Shi, Huabin; Yu, Xiping; Dalrymple, Robert A.

2017-12-01

A SPH model based on a general formulation for solid-fluid two-phase flows is proposed for suspended sediment motion in free surface flows. The water and the sediment are treated as two miscible fluids, and the multi-fluid system is discretized by a single set of SPH particles, which move with the water velocity and carry properties of the two phases. Large eddy simulation (LES) is introduced to deal with the turbulence effect, and the widely used Smagorinsky model is modified to take into account the influence of sediment particles on the turbulence. The drag force is accurately formulated by including the hindered settling effect. In the model, the water is assumed to be weakly compressible while the sediment is incompressible, and a new equation of state is proposed for the pressure in the sediment-water mixture. Dynamic boundary condition is employed to treat wall boundaries, and a new strategy of Shepard filtering is adopted to damp the pressure oscillation. The developed two-phase SPH model is validated by comparing the numerical results with analytical solutions for idealized cases of still water containing both neutrally buoyant and naturally settling sand and for plane Poiseuille flows carrying neutrally buoyant particles, and is then applied to sand dumping from a line source into a water tank, where the sand cloud settles with a response of the free water surface. It is shown that the numerical results are in good agreement with the experimental data as well as the empirical formulas. The characteristics of the settling sand cloud, the pressure field, and the flow vortices are studied. The motion of the free water surface is also discussed. The proposed two-phase SPH model is proven to be effective for numerical simulation of sand dumping into waters.

Toxicity of sediments and pore water from Brunswick Estuary, Georgia

Science.gov (United States)

Winger, Parley V.; Lasier, Peter J.; Geitner, Harvey

1993-01-01

A chlor-alkali plant in Brunswick, Georgia, USA, discharged >2 kg mercury/d into a tributary of the Turtle River-Brunswick Estuary from 1966 to 1971. Mercury concentrations in sediments collected in 1989 along the tributary near the chlor-alkali plant ranged from 1 to 27 μg/g (dry weight), with the highest concentrations found in surface (0–8 cm) sediments of subtidal zones in the vicinity of the discharge site. Toxicity screening in 1990 using Microtox® bioassays on pore water extracted on site from sediments collected at six stations distributed along the tributary indicated that pore water was highly toxic near the plant discharge. Ten-day toxicity tests on pore water from subsequent sediment samples collected near the plant discharge confirmed high toxicity to Hyalella azteca, and feeding activity was significantly reduced in whole-sediment tests. In addition to mercury in the sediments, other metals (chromium, lead, and zinc) exceeded 50 μg/g, and polychlorobiphenyl (PCB) concentrations ranged from 67 to 95 μg/g. On a molar basis, acid-volatile sulfide concentrations (20–45 μmol/g) in the sediments exceeded the metal concentrations. Because acid-volatile sulfides bind with cationic metals and form metal sulfides, which are generally not bioavailable, toxicities shown by these sediments were attributed to the high concentrations of PCBs and possibly methylmercury.

Influence of sediment organic enrichment and water alkalinity on growth of aquatic isoetid and elodeid plants

DEFF Research Database (Denmark)

Raun, Ane-Marie Løvendahl; Borum, Jens; Jensen, Kaj Sand

2010-01-01

1. Lake eutrophication has increased phytoplankton blooms and sediment organic matter. Among higher plants, small, oligotrophic rosette species (isoetids) have disappeared, while a few tall, eutrophic species (elodeids) may have persisted. Despite recent reduction of nutrient loading in restored...... lakes, the vegetation has rarely regained its former composition and coverage. Patterns of recovery may depend on local alkalinity because HCO3- stimulates photosynthesis of elodeids and not of isoetids. In laboratory growth experiments with two isoetids (Lobelia dortmanna and Littorella uniflora......) and two elodeids (Potamogeton crispus and P. perfoliatus), we test whether organic enrichment of lake sediments has a long-lasting influence by: (i) reducing plant growth because of oxygen stress on plant roots and (ii) inhibiting growth more for isoetids than elodeids. We also test whether (iii...

Oxidative stress induced on Cyprinus carpio by contaminants present in the water and sediment of Madin Reservoir.

Science.gov (United States)

Galar-Martinez, Marcela; Gomez-Olivan, Leobardo Manuel; Amaya-Chavez, Araceli; Razo-Estrada, Celene; Garcia-Medina, Sandra

2010-01-01

Madin Reservoir (MR), located in the State of Mexico, is fed mainly by the Rio Tlalnepantla. MR supplies potable water to the municipalities of Naucalpan and Atizapan, and various recreational activities take place in its vicinity, such as sailing and the fishing of diverse species including the common carp Cyprinus carpio. The purpose of this study was to determine the toxic effects of contaminants present in MR water and sediment on C. carpio. Five sampling stations were selected (those considered to have the most problems due to discharges). Water and sediment samples were taken and toxicity studies were performed, including acute toxicity (lethality) and subacute toxicity assays. The biomarkers used in the subacute assays were lipid peroxidation (LPX) and activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) in the liver and brain of test organisms. These biomarkers were also evaluated in local carp, i.e. carp with chronic exposure in situ to reservoir contaminants. Results show that contaminants in the water and sediment of the different sampling stations induce oxidative stress, this toxicity being more evident in samples from stations near the entry point of the Rio Tlalnepantla tributary and in local carp. This may be due to high contaminant levels as well as the fact that the physicochemical characteristics of the matrices might favor their bioavailability. Thus, both the water and sediment of this reservoir are contaminated with xenobiotics hazardous to C. carpio, a species consumed by the local human population.

Enantioselective analysis of ibuprofen and its biotransformation products in water/sediment systems,

DEFF Research Database (Denmark)

Sundström, Maria; Escola, Monica; Radke, Michael

2015-01-01

of the sediments in the aquatic systems has neither been taken in account previously. In this study, four water-sediment systems were chosen according to anthropogenic exposure and sediment conditions. A low anthropogenic impact lake (Largen), a river receiving wastewater (Fyrisån) and two sediments (anoxic......As ibuprofen degrades enantioselectively in activated sludge, the same process is assumed to occur in surface lake-water and in river-water based biofilms. Yet, the effects of the wastewater inflow, containing non-racemic ibuprofen, into natural systems have never been studied. The role......-7 days in Tvären and B1 respectively. Largen sediments, not impacted by wastewater, degraded ibuprofen faster than Fyrisån sediments did. Yet, these two sediments sediments showed no significant difference with respect to the degradation rates of the ibuprofen enantiomers. A connection between wastewater...

Sediment-stabilizing and Destabilizing Ecoengineering Species from River to Estuary: the Case of the Scheldt System

Science.gov (United States)

Selakovic, S.; Cozzoli, F.; Leuven, J.; Van Braeckel, A.; Speybroeck, J.; Kleinhans, M. G.; Bouma, T.

2017-12-01

Interactions between organisms and landscape forming processes play an important role in evolution of coastal landscapes. In particular, biota has a strong potential to interact with important geomorphological processes such as sediment dynamics. Although many studies worked towards quantifying the impact of different species groups on sediment dynamics, information has been gathered on an ad hoc base. Depending on species' traits and distribution, functional groups of ecoengineering species may have differential effects on sediment deposition and erosion. We hypothesize that the spatial distributions of sediment-stabilizing and destabilizing species across the channel and along the whole salinity gradient of an estuary partly determine the planform shape and channel-shoal morphology of estuaries. To test this hypothesis, we analyze vegetation and macrobenthic data taking the Scheldt river-estuarine continuum as model ecosystem. We identify species traits with important effects on sediment dynamics and use them to form functional groups. By using linearized mixed modelling, we are able to accurately describe the distributions of the different functional groups. We observe a clear distinction of dominant ecosystem engineering functional groups and their potential effects on the sediment in the river-estuarine continuum. The first results of longitudinal cross section show the highest effects of stabilizing plant species in riverine and sediment bioturbators in weak polyhaline part of continuum. The distribution of functional groups in transverse cross sections shows dominant stabilizing effect in supratidal zone compared to dominant destabilizing effect in the lower intertidal zone. This analysis offers a new and more general conceptualization of distributions of sediment stabilizing and destabilizing functional groups and their potential impacts on sediment dynamics, shoal patterns, and planform shapes in river-estuarine continuum. We intend to test this in future

Copper, Cadmium and Lead in superficial sediment, water and the fish Cyprinodon Dearborni, in two Lagoons of Venezuela

International Nuclear Information System (INIS)

Toledo, J.; Lemus, M.; Chung, K. S

2000-01-01

The concentration of copper, cadmium and lead in superficial sediment, water and the fish Cyprenodon dearborni was determined in two coastal lagoons of Sucre State, Venezuela. Chacopata lagoon is hyper saline while Los Patos Lagoon is hypo saline and receives significant waste water from Cumana city. Water, sediment and fish samples were collected in Frebruary 1998. In the laboratory, samples underwent acid digestion and were analysed by atomic absorption spectrophotometry. The mean values of the metals in C dearborni from the Chacopata lagoon were: 159.26± 210.68 μg/g for Cu, 44.71±45.58 μg/g for Cd, and 9.31±23.34 μg/g for Pb, while for Los Patos lagoon the mean values were: 64.88±16.30, 19.48± 5.81 and 22.85±20.00, respectively. In the water column, the metal concentration ranges were: 2.3-11.6, 3.9-5.4 and 21-32 mg/l for cooper, cadmium and lead, respectively. These results suggest that metal levels in sediment, water column and organisms in both lagoons do not differ, except for lead, even though only Los Patos receives waste water. (Author) [es

Acclimation of Hydrilla verticillata to sediment anoxia in vegetation restoration in eutrophic waters.

Science.gov (United States)

Wu, Juan; Dai, Yanran; Rui, Shengyang; Cui, Naxin; Zhong, Fei; Cheng, Shuiping

2015-12-01

Sediment anoxia generally results from intense organic enrichment and is a limiting factor in the restoration of vegetation in eutrophic waters. To investigate the effect of sediment anoxia on a typical pollution-tolerant submerged macrophyte species, Hydrilla verticillata, and acclimation mechanisms in the plant, a gradient of sediment anoxia was simulated with additions of sucrose to the sediment, which can stimulate increased concentrations of total nitrogen, NH4(+) and Fe in pore water. H. verticillata growth was significantly affected by highly anoxic conditions, as indicated by reduced total biomass in the 0.5 and 1% sucrose treatments. However, slight anoxia (0.1% sucrose addition) promoted growth, and the shoot biomass was 22.64% higher than in the control. In addition to morphologic alterations, H. verticillata showed physiological acclimations to anoxia, including increased anaerobic respiration and changes in carbon and nitrogen metabolism in roots. The soluble protein and soluble carbohydrate contents in roots of the 1% treatment were both significantly higher compared with those in the control. The increase in alcohol dehydrogenase activity and pyruvate content in the roots suggested that H. verticillata has a well-developed capacity for anaerobic fermentation. This study suggests that highly anoxic sediments inhibit the growth of H. verticillata and the species has a degree of tolerance to anoxic conditions. Further in situ investigations should be conducted on the interactions between sediment conditions and macrophytes to comprehensively evaluate the roles of sediment in the restoration of vegetation in eutrophic waters.

Heavy metal partitioning of suspended particulate matter-water and sediment-water in the Yangtze Estuary.

Science.gov (United States)

Feng, Chenghong; Guo, Xiaoyu; Yin, Su; Tian, Chenhao; Li, Yangyang; Shen, Zhenyao

2017-10-01

The partitioning of ten heavy metals (As, Cd, Co, Cr, Cu, Hg, Ni, Pb, Sb, and Zn) between the water, suspended particulate matter (SPM), and sediments in seven channel sections during three hydrologic seasons in the Yangtze Estuary was comprehensively investigated. Special attention was paid to the role of tides, influential factors (concentrations of SPM and dissolved organic carbon, and particle size), and heavy metal speciation. The SPM-water and sediment-water partition coefficients (K p ) of the heavy metals exhibited similar changes along the channel sections, though the former were larger throughout the estuary. Because of the higher salinity, the K p values of most of the metals were higher in the north branch than in the south branch. The K p values of Cd, Co, and As generally decreased from the wet season to the dry season. Both the diagonal line method and paired samples t-test showed that no specific phase transfer of heavy metals existed during the flood and ebb tides, but the sediment-water K p was more concentrated for the diagonal line method, owing to the relatively smaller tidal influences on the sediment. The partition coefficients (especially the K p for SPM-water) had negative correlations with the dissolved organic carbon (DOC) but positive correlations were noted with the particle size for most of the heavy metals in sediment. Two types of significant correlations were observed between K p and metal speciation (i.e., exchangeable, carbonate, reducible, organic, and residual fractions), which can be used to identify the dominant phase-partition mechanisms (e.g., adsorption or desorption) of heavy metals. Copyright © 2017 Elsevier Ltd. All rights reserved.

Discriminating sediment and clear water over coastal water using GD technique

Directory of Open Access Journals (Sweden)

Amin Abd Rahman Mat

2017-03-01

Full Text Available Currently two algorithms are being used routinely by the MODIS Atmosphere and Ocean Team in order to distinguish sediment influence and clear water pixels over turbid water area. These two algorithms require complicated computational analyses. In this paper, a simple algorithm based on empirical technique to detect the sediment-influenced pixels over coastal waters is proposed as an alternative to these two algorithms. This study used apparent reflectance acquired from MODIS L1B product. This algorithm is based on the gradient difference of the line connecting the 0.47- and 1.24-μm channels and 0.47- and 0.66-μm channels of a log-log graph of the apparent reflectance values against MODIS wavelengths. Over clear-water areas (deep blue sea, the 0.47-, 0.66- and 1.24-μm channels fitted very well in line with correlation R > 0.99. Over turbid waters, a substantial increase of 0.66 μm in the reflectance leads to a low correlation value. By computing the difference between the gradient of the line connecting 0.47 and 0.66 μm and the gradient of the line connecting 0.47 and 1.24 μm, the threshold to discriminate turbid and shallow coastal waters from clear-water pixels can be obtained. If the gradient difference is greater than 0, the pixels were then marked as sediment-influenced pixels. This proposed algorithm works well for MODIS Terra and Aqua sensor. The comparison of this algorithm with an established algorithm also showed a good agreement.

Effect of water flux and sediment discharge of the Yangtze River on PAHs sedimentation in the estuary.

Science.gov (United States)

Li, Rufeng; Feng, Chenghong; Wang, Dongxin; He, Maozhi; Hu, Lijuan; Shen, Zhenyao

2016-12-01

Historical distribution characteristics of polycyclic aromatic hydrocarbons (PAHs) and their carriers (i.e., organic matter and mineral particles) in the sediment cores of the Yangtze Estuary were investigated, with emphasis laid on the role of the Yangtze River. Grain size component of sediments (clay, silt, and sand) and organic carbon (black carbon and total organic carbon) in the sediment cores were markedly affected by water flux and sediment discharge of the Yangtze River. Qualitative and quantitative analysis results showed that sands and black carbon acted as the main carriers of PAHs. The sedimentation of two-ring to three-ring PAHs in the estuary had significant correlations with water flux and sediment discharge of the Yangtze River. The relative lower level of the four-ring and five-ring to six-ring PAHs concentrations appeared around the year 2003 and remained for the following several years. This time period accorded well with the water impoundment time of the Three Gorges Reservoir. The decreased level of two-ring to three-ring PAHs occurred in the year 1994, and the peak points around the year 2009 indicated that PAHs sedimentation in the estuary also had close relationship to severe drought and flood in the catchments. The findings presented in this paper could provide references for assessing the impacts of water flux and sediment discharge on the historical deposition of PAHs and their carriers in the Yangtze Estuary.

Occurence of antibiotic compounds found in the water column and bottom sediments from a stream receiving two waste water treatment plant effluents in northern New Jersey, 2008

Science.gov (United States)

Gibs, Jacob; Heckathorn, Heather A.; Meyer, Michael T.; Klapinski, Frank R.; Alebus, Marzooq; Lippincott, Robert

2013-01-01

An urban watershed in northern New Jersey was studied to determine the presence of four classes of antibiotic compounds (macrolides, fluoroquinolones, sulfonamides, and tetracyclines) and six degradates in the water column and bottom sediments upstream and downstream from the discharges of two wastewater treatment plants (WWTPs) and a drinking-water intake (DWI). Many antibiotic compounds in the four classes not removed by conventional WWTPs enter receiving waters and partition to stream sediments. Samples were collected at nine sampling locations on 2 days in September 2008. Two of the nine sampling locations were background sites upstream from two WWTP discharges on Hohokus Brook. Another background site was located upstream from a DWI on the Saddle River above the confluence with Hohokus Brook. Because there is a weir downstream of the confluence of Hohokus Brook and Saddle River, the DWI receives water from Hohokus Brook at low stream flows. Eight antibiotic compounds (azithromycin (maximum concentration 0.24 μg/L), ciprofloxacin (0.08 μg/L), enrofloxacin (0.015 μg/L), erythromycin (0.024 μg/L), ofloxacin (0.92 μg/L), sulfamethazine (0.018 μg/L), sulfamethoxazole (0.25 μg/L), and trimethoprim (0.14 μg/L)) and a degradate (erythromycin-H2O (0.84 μg/L)) were detected in the water samples from the sites downstream from the WWTP discharges. The concentrations of six of the eight detected compounds and the detected degradate compound decreased with increasing distance downstream from the WWTP discharges. Azithromycin, ciprofloxacin, ofloxacin, and trimethoprim were detected in stream-bottom sediments. The concentrations of three of the four compounds detected in sediments were highest at a sampling site located downstream from the WWTP discharges. Trimethoprim was detected in the sediments from a background site. Pseudo-partition coefficients normalized for streambed sediment organic carbon concentration were calculated for azithromycin, ciprofloxacin, and

Sediment toxicity testing with the amphipod Ampelisca abdita in Calcasieu Estuary, Louisiana

Science.gov (United States)

Redmond, M.S.; Crocker, P.A.; McKenna, K.M.; Petrocelli, E.A.; Scott, K.J.; Demas, C.R.

1996-01-01

Discharges from chemical and petrochemical manufacturing facilities have contaminated portions of Louisiana's Calcasieu River estuary with a variety of organic and inorganic contaminants. As part of a special study, sediment toxicity testing was conducted to assess potential impact to the benthic community. Ten-day flow-through sediment toxicity tests with the amphipod Ampelisca abdita revealed significant toxicity at 68% (26 of 38) of the stations tested. A. abdita mortality was highest in the effluent-dominated bayous, which are tributaries to the Calcasieu River. Mortality was correlated with total heavy metal and total organic compound concentrations in the sediments. Ancillary experiments showed that sediment interstitial water salinity as low as 2.5 o/o-o did not significantly affect A. abdita's, response in the flow-through system; sediment storage for 7 weeks at 4??C did not significantly affect toxicity. Sediment toxicity to A. abdita was more prevalent than receiving water toxicity using three short-term chronic bioassays. Results suggest that toxicity testing using this amphipod is a valuable tool when assessing sediments containing complex contaminant mixtures and for assessing effects of pollutant loading over time. In conjunction with chemical analyses, the testing indicated that the effluent-dominated, brackish bayous (Bayou d'Inde and Bayou Verdine) were the portions of the estuary most impacted by toxicity.

Using an interlaboratory study to revise methods for conducting 10-d to 42-d water or sediment toxicity tests with Hyalella azteca

Science.gov (United States)

Ivey, Chris D.; Ingersoll, Christopher G.; Brumbaugh, William G.; Hammer, Edward J.; Mount, David R.; Hockett, J. Russell; Norberg-King, Teresa J.; Soucek, Dave; Taylor, Lisa

2016-01-01

Studies have been conducted to refine US Environmental Protection Agency, ASTM International, and Environment Canada standard methods for conducting 42-d reproduction tests with Hyalella azteca in water or in sediment. Modifications to the H. azteca method include better-defined ionic composition requirements for exposure water (i.e., >15 mg/L of chloride and >0.02 mg/L of bromide) and improved survival, growth, and reproduction with alternate diets provided as increased rations over time in water-only or whole-sediment toxicity tests. A total of 24 laboratories volunteered to participate in the present interlaboratory study evaluating the performance of H. azteca in 42-d studies in control sand or control sediment using the refined methods. Improved growth and reproduction of H. azteca was observed with 2 alternate diets of 1) ramped diatoms (Thalassiosira weissflogii) + ramped Tetramin or 2) yeast–cerophyll–trout chow (YCT) + ramped Tetramin, especially when compared with results from the traditional diet of 1.8 mg YCT/d. Laboratories were able to meet proposed test acceptability criteria and in most cases had lower variation in growth or reproduction compared with previous interlaboratory studies using the traditional YCT diet. Laboratory success in conducting 42-d H. azteca exposures benefited from adherence to several key requirements of the detailed testing, culturing, and handling methods. Results from the present interlaboratory study are being used to help revise standard methods for conducting 10-d to 42-d water or sediment toxicity exposures with H. azteca.

Water and sediment temperature dynamics in shallow tidal environments: The role of the heat flux at the sediment-water interface

Science.gov (United States)

Pivato, M.; Carniello, L.; Gardner, J.; Silvestri, S.; Marani, M.

2018-03-01

In the present study, we investigate the energy flux at the sediment-water interface and the relevance of the heat exchanged between water and sediment for the water temperature dynamics in shallow coastal environments. Water and sediment temperature data collected in the Venice lagoon show that, in shallow, temperate lagoons, temperature is uniform within the water column, and enabled us to estimate the net heat flux at the sediment-water interface. We modeled this flux as the sum of a conductive component and of the solar radiation reaching the bottom, finding the latter being negligible. We developed a "point" model to describe the temperature dynamics of the sediment-water continuum driven by vertical energy transfer. We applied the model considering conditions characterized by negligible advection, obtaining satisfactory results. We found that the heat exchange between water and sediment is crucial for describing sediment temperature but plays a minor role on the water temperature.

Water and sediment temperatures at mussel beds in the upper Mississippi River basin

Science.gov (United States)

Newton, Teresa J.; Sauer, Jennifer; Karns, Byron

2013-01-01

Native freshwater mussels are in global decline and urgently need protection and conservation. Declines in the abundance and diversity of North American mussels have been attributed to human activities that cause pollution, waterquality degradation, and habitat destruction. Recent studies suggest that effects of climate change may also endanger native mussel assemblages, as many mussel species are living close to their upper thermal tolerances. Adult and juvenile mussels spend a large fraction of their lives burrowed into sediments of rivers and lakes. Our objective was to measure surface water and sediment temperatures at known mussel beds in the Upper Mississippi (UMR) and St. Croix (SCR) rivers to estimate the potential for sediments to serve as thermal refugia. Across four mussel beds in the UMR and SCR, surface waters were generally warmer than sediments in summer, and were cooler than sediments in winter. This suggests that sediments may act as a thermal buffer for mussels in these large rivers. Although the magnitude of this effect was usually cause mortality in laboratory studies. These data suggest that elevated water temperatures resulting from global warming, thermal discharges, water extraction, and/or droughts have the potential to adversely affect native mussel assemblages.

Water and bottom sediments quality of brackish water shrimp farms in Kaliganj Upazila, Satkhira, Bangladesh

Directory of Open Access Journals (Sweden)

Mohammed Aktaruzzaman, Mohammed Shakhaoat Hossain, Abu Naieum Muhammad Fakhruddin, Mohammed Jamal Uddin, Syed Hafizur Rahman

2013-05-01

Full Text Available Shrimp culture plays a central part in the fisheries sector of Bangladesh that leads to a significant change in the structure and composition of frozen food export sector. An investigation was carried out to determine physiochemical parameters, nutrients content, bacterial contamination and metal content in shrimp “Gher” (Farms water and sediments. Physicochemical parameters were analyzed in situ by portable meters. Ammonia, phosphate, bacterial counts, and metals contents were analyzed by Nesslerization, colorimetric and standard microbiological methods and Atomic Absorption Spectrophotometery (AAS, respectively. Except Dissolve oxygen and temperature all other physiochemical parameters were unsuitable for shrimp culture. The concentration of ammonia was 0.384 to 1.5 mg L-1 and the concentration of phosphate ranged from 0.02 to 0.818 mg L-1. In bacteriological analysis, highest levels of coliform were found in the tested samples and total colifom count reached up to 2.04x103 cfu mL-1. Among the tested metals, Cr was highest in water and sediment samples. Concentration of Cr ranged from 0.150 to 0.807 mg L-1 and 1.957 to 3.436 mg kg-1 in water and sediment samples, respectively. A significant difference was observed for the concentration of metals in sediment and water samples. The high concentration of nutrients and metals in shrimp “Gher” water and sediment as well as the presence of pathogenic bacteria in the “Gher” and river water indicated unhygienic environment and the sources of contamination of shrimp “Gher”.

The evaluation of the equilibrium partitioning method using sensitivity distributions of species in water and soil or sediment

NARCIS (Netherlands)

Beelen P van; Verbruggen EMJ; Peijnenburg WJGM; ECO

2002-01-01

The equilibrium partitioning method (EqP-method) can be used to derive environmental quality standards (like the Maximum Permissible Concentration or the intervention value) for soil or sediment, from aquatic toxicity data and a soil/water or sediment/water partitioning coefficient. The validity of

Mobilization of radionuclides from sediments. Potential sources to Arctic waters

International Nuclear Information System (INIS)

Oughton, D.H.; Boerretzen, P.; Mathisen, B.; Salbu, B.; Tronstad, E.

1995-01-01

Contaminated soils and sediments can act as secondary sources of radionuclides to Arctic waters. In cases where the original source of contamination has ceased or been greatly reduced (e.g., weapons' testing, waste discharges from Mayak and Sellafield) remobilization of radionuclides from preciously contaminated sediments increases in importance. With respect to Arctic waters, potential secondary sources include sediments contaminated by weapons' testing, by discharges from nuclear installations to seawater, e.g., the Irish Sea, or by leakages from dumped waste containers. The major land-based source is run-off from soils and transport from sediments in the catchment areas of the Ob and Yenisey rivers, including those contaminated by Mayak discharges. Remobilization of radionuclides is often described as a secondary source of contamination. Whereas primary sources of man-made radionuclides tend to be point sources, secondary sources are usually more diffuse. Experiments were carried out on marine (Kara Sea, Irish Sea, Stepovogo and Abrosimov Fjords), estuarine (Ob-Yenisey) and dirty ice sediments. Total 137 Cs and 90 Sr concentrations were determined using standard radiochemical techniques. Tracer studies using 134 Cs and 85 Sr were used to investigate the kinetics of radionuclide adsorption and desorption. It is concluded that 90 Sr is much less strongly bound to marine sediments than 137 Cs, and can be chemically mobilized through ion exchange with elements is seawater. Radiocaesium is strongly and rapidly fixed to sediments. Discharges of 137 Cs to surface sediments (i.e., from dumped containers) would be expected to be retained in sediments to a greater extent than discharges to sea-waters. Physical mobilization of sediments, for example resuspension, may be of more importance for transport of 137 Cs than for 90 Sr. 7 refs., 4 figs

Interaction between water, sediments and radionuclides

International Nuclear Information System (INIS)

Snodgrass, W.J.; McKee, P.; Garnett, J.; Stieff, L.

1988-08-01

A model-based measurements program was carried out to evaluate the primary mechanisms controlling transport of uranium 238 and thorium 232 decay chain radionuclides in Quirke Lake, a water body draining much of the uranium mining and milling district near Elliot Lake, Ontario. This program included studies of radionuclide accumulation in sediments, particle settling and lake mass-balance studies. Also, sediment studies were undertaken to evaluate chemical fractionation, mineralogical associations, and sediment-water adsorption and release. A limnocorral experiment was conducted in an isolated portion of a lake to measure radium 226 removal from the water column and diffusion from the sediments back to the water. Modelling studies were made to assess the data. Substantial agreement was obtained using the model originally developed for the AECB between model predictions and observations for Quirke Lake and for the limnocorrals. Further work is required to complete the studies undertaken in this project to assess the significance of the efflux of radionuclides from the sediments. These studies include a laboratory program to measure kinetics of adsorption, sediment-water modelling studies of the results and a field measurement program to develop a mass-balance analysis for thorium. (numerous refs)

Polyphosphates as a source of enhanced P fluxes in marine sediments overlain by anoxic waters: Evidence from 31P NMR

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Ingall Ellery

2005-06-01

Full Text Available Sedimentary phosphorus (P composition was investigated in Effingham Inlet, a fjord located on the west coast of Vancouver Island in Barkley Sound. Solid-state 31P nuclear magnetic resonance (NMR spectroscopy was applied to demineralized sediment samples from sites overlain by oxic and anoxic bottom waters. The two sites were similar in terms of key diagenetic parameters, including the mass accumulation rate, integrated sulfate reduction rate, and bulk sediment organic carbon content. In contrast, P benthic fluxes were much higher at the anoxic site. 31P NMR results show that P esters and phosphonates are the major organic P species present at the surface and at depth in sediments at both sites. Polyphosphates were only found in the surface sediment of the site overlain by oxic waters. The varying stability of polyphosphates in microorganisms under different redox conditions may, in part, explain their distribution as well as differences in P flux between the two sites.

Simultaneous determination of butyltin and phenyltin species in sediments using ultrasound-assisted leaching

Energy Technology Data Exchange (ETDEWEB)

Carpinteiro, J.; Rodriguez, I.; Cela, R. [Dpto. Quimica Analitica, Nutricion y Bromatologia, Universidad de Santiago de Compostela (Spain)

2001-08-01

A fast and simple procedure is presented for the simultaneous leaching of butyl (mono, di and tributyl) and phenyl organotin species from sediment samples. Leached compounds are further ethylated with sodium tetraethylborate in aqueous medium, and analyzed by gas chromatography. After testing the stability of triphenyltin under different extraction conditions, ultrasound-assisted leaching at room temperature in the presence of acetic acid was been proposed as an extraction procedure compatible with the simultaneous determination of phenyl- and butyltin compounds in sediments. Recoveries between 70 and 90% were obtained for phenyl species in spiked samples prepared in the laboratory. Results for butyltin species were validated by use of the reference material PACS-2. Quantification limits, using GC-MIP-AES as measurement technique, were approximately 5-10 ng g{sup -1}. Precision in the consecutive analysis of three sediment samples varied between 3 and 10%. (orig.)

Rates of nocturnal transpiration in two evergreen temperate woodland species with differing water-use strategies.

Science.gov (United States)

Zeppel, Melanie; Tissue, David; Taylor, Daniel; Macinnis-Ng, Catriona; Eamus, Derek

2010-08-01

Nocturnal fluxes may be a significant factor in the annual water budget of forested ecosystems. Here, we assessed sap flow in two co-occurring evergreen species (Eucalyptus parramattensis and Angophora bakeri) in a temperate woodland for 2 years in order to quantify the magnitude of seasonal nocturnal sap flow (E(n)) under different environmental conditions. The two species showed different diurnal water relations, demonstrated by different diurnal curves of stomatal conductance, sap flow and leaf water potential. The relative influence of several microclimatic variables, including wind speed (U), vapour pressure deficit (D), the product of U and D (UD) and soil moisture content, were quantified. D exerted the strongest influence on E(n) (r² = 0.59-0.86), soil moisture content influenced E(n) when D was constant, but U and UD did not generally influence E(n). In both species, cuticular conductance (G(c)) was a small proportion of total leaf conductance (G(s)) and was not a major pathway for E(n). We found that E(n) was primarily a function of transpiration from the canopy rather than refilling of stem storage, with canopy transpiration accounting for 50-70% of nocturnal flows. Mean E(n) was 6-8% of the 24-h flux across seasons (spring, summer and winter), but was up to 19% of the 24-h flux on some days in both species. Despite different daytime strategies in water use of the two species, both species demonstrated low night-time water loss, suggesting similar controls on water loss at night. In order to account for the impact of E(n) on pre-dawn leaf water potential arising from the influence of disequilibria between root zone and leaf water potential, we also developed a simple model to more accurately predict soil water potential (ψ(s)).

Comparison of test specific sediment effect concentrations with marine sediment quality assessment guidelines

International Nuclear Information System (INIS)

Carr, R.S.; Biedenbach, J.M.; MacDonald, D.D.

1995-01-01

As part of NOAA's National Status and Trends (NS and T) Bioeffects Assessment program and studies conducted by the National Biological Service, numerous sediment quality assessment surveys have recently been conducted along the Atlantic and Gulf coasts of the US using the sea urchin (Arbacia punctulata) fertilization and embryological development tests with pore water. Additional toxicity tests were also conducted in conjunction with most of these studies. The areas that have been sampled include Boston harbor, Massachusetts; Charleston Harbor, Winyah Bay, and Savannah River, South Carolina; St. Simon Sound, Georgia; Biscayne Bay, Tampa Bay, Choctawhatchee Bay, Apalachicola Bay, St. Andrew Bay, and Pensacola Bay, Florida; Galveston Bay, Lavaca Bay, and Sabine Lake, Texas, and 200 stations in the vicinity of offshore oil and gas production platforms in the Gulf of Mexico. Sufficient data are now available from this series of surveys to calculate test specific sediment effect concentrations (SECs). Based on these recent studies, SECs were developed for the sea urchin porewater and amphipod tests and compared with existing marine sediment quality assessment guidelines

Sediment core fossils in ancient Lake Ohrid: testing for faunal change since the Last Interglacial

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C. Albrecht

2010-11-01

Full Text Available Ancient Lake Ohrid is probably of early Pleistocene or Pliocene origin and amongst the few lakes in the world harbouring an outstanding degree of endemic biodiversity. Although there is a long history of evolutionary research in Lake Ohrid, particularly on molluscs, a mollusc fossil record has been missing up to date. For the first time, gastropod and bivalve fossils are reported from the basal, calcareous part of a 2.6 m long sediment succession (core Co1200 from the north-eastern part of Lake Ohrid. Electron spin resonance (ESR dating of mollusc shells from the same stratigraphic level yielded an age of 130 ± 28 ka. Lithofacies III sediments, i.e. a stratigraphic subdivision comprising the basal succession of core Co1200 between 181.5–263 cm, appeared solid, greyish-white, and consisted almost entirely of silt-sized endogenic calcite (CaCO₃>70% and intact and broken mollusc shells. Here we compare the faunal composition of the thanatocoenosis with recent mollusc associations in Lake Ohrid. A total of 13 mollusc species (9 gastropod and 4 bivalve species could be identified within Lithofacies III sediments. The value of sediment core fossils for reconstructing palaeoenvironmental settings was evaluated and the agreement between sediment and palaeontological proxies was tested.

The study also aims at investigating major faunal changes since the Last Interglacial and searching for signs of extinction events.

The combined findings of the ecological study and the sediment characteristics suggest deposition in a shallow water environment during the Last Interglacial. The fossil fauna exclusively included species also found in the present fauna, i.e. no extinction events are evident for this site since the Last Interglacial. The thanatocoenosis showed the highest similarity with recent Intermediate Layer (5–25 m water depth mollusc assemblages. The demonstrated existence of a mollusc fossil record in Lake Ohrid

Microscale ecotoxicity testing of Moselle river watershed (Lorraine Province, France sediments

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Jean François Férard

2015-06-01

Full Text Available The ecotoxic potential of seven Moselle river watershed sediments was assessed with a battery of bioassays comprised of rapid phototrophic [LuminoTox solid phase (L-SPA and elutriate (L-ELU assays] and bacterial [Microtox solid phase assay (M-SPA] exposure tests, as well as with two micro-invertebrate solid phase tests conducted with Hydra attenuata (lethal and sublethal effects solid phase assay, HL-SPA and HSL-SPA and Chironomus riparius. Measured effects of sediments and their elutriates were varied and reflected responses that were ecotoxicity test-, endpoint- and site-dependent, suggesting some degree of risk toward benthic and water column organisms, respectively, at specific sites. Correlation analysis demonstrated that L-SPA and M-SPA ecotoxicity responses were significantly linked with the Hydra HSL-SPA assay, indicating their ability to predict ecotoxicity towards an invertebrate taxonomic group representing secondary consumers. While the L-SPA and M-SPA assays hold promise as rapid screens for sediment ecotoxicity, correlation analysis with grain size (L-SPA: r=-0.795, P=0.033; M-SPA: r=-0.73, P=0.07 points out that their responses can be influenced by the presence of fines (i.e., sediment particles ≤0.063 mm in size and that this information is essential to properly interpret ecotoxicity data generated with these assays. Finally, notable differences observed in trophic level sensitivities once again recall the importance of employing a test battery to adequately appraise the ecotoxicity of sediments.

Minimal barcode distance between two water mite species from Madeira Island: a cautionary tale.

Science.gov (United States)

García-Jiménez, Ricardo; Horreo, Jose Luis; Valdecasas, Antonio G

2017-06-01

In this work, we compare morphological and molecular data in their ability to distinguish between species of water mites (Acari, Prostigmata, Hydrachnidia). We have focused on the two species of the genus Lebertia inhabiting the island of Madeira. While traditional morphological traits were initially sufficient to distinguish between these two species, the molecular data were more dependable on the kind of analysis carried out. Single arbitrary genetic distance (e.g. a K2P distance below 2%) may lead to the conclusion that the specimens under study belong to the same species. Analysing the same specimens with the coalescent model has proved the evolutionary independence of both Lebertia clades in Madeira. Furthermore, multi-rate Poisson Tree Process analysis confirmed both lineages as independent species. Our results agree with previous studies warning of the dangers of rigid species delimitation based on arbitrary molecular distances. In addition, the importance of different molecular data approaches for correct species delimitation in water mites is highlighted.

The impact of water pollution on fish species in southeast region of Goiás, Brazil.

Science.gov (United States)

Vaz S Silva, Sabrina; Dias, Aurélio Henrique C; Dutra, Elaine S; Pavanin, Alfredo L; Morelli, Sandra; Pereira, Boscolli B

2016-01-01

The rivers from the region of Catalão, Southeast Goiás State, Brazil, are exposed to intense anthropogenic influences including agricultural activities, industry, and urban waste. The aim of this study was to determine the severity of water pollution by conducting an experiment involving in situ biomonitoring of water constituents on genotoxicity in fish inhabiting these sites. The genotoxicity of three sites of the region were analyzed utilizing the micronucleus (MN) test. It was of interest to determine whether there were differences between sampling sites such as urban perimeter, agriculture, and fertilizer industry in control, and monitored species including Astyanax fasciatus, Astyanax altiparanae, and Characidium fasciatum. Data demonstrated that the species at sites 1, 2, and 3 exhibited a marked increase in frequency of MN compared to fish from site 4. Significant elevation in frequency of MN occurred in erythrocytes of A. fasciatus and A. altiparanae at sites 1 and 2. At site 3 higher frequencies of MN were observed in C. fasciatum. MN induction in C. fasciatum was correlated with chromium levels in water and sediment, while A. fasciatum and A. altiparanae showed an association with zinc in water and sediment. Data suggest that benthic and nektonic fish species display different sensitivities in relation to anthropogenic contaminant influences.

Water quality assessment in the "German River of the years 2014/2015": how a case study on the impact of a storm water sedimentation basin displayed impairment of fish health in the Argen River (Southern Germany).

Science.gov (United States)

Thellmann, Paul; Kuch, Bertram; Wurm, Karl; Köhler, Heinz-R; Triebskorn, Rita

2017-01-01

The present work investigates the impact of discharges from a storm water sedimentation basin (SSB) receiving runoff from a connected motorway in southern Germany. The study lasted for almost two years and was aimed at assessing the impact of the SSB on the fauna of the Argen River, which is a tributary of Lake Constance. Two sampling sites were examined up- and downstream of the SSB effluent. A combination of different diagnostic methods (fish embryo test with the zebrafish, histopathology, micronucleus test) was applied to investigate health impairment and genotoxic effects in indigenous fish as well as embryotoxic potentials in surface water and sediment samples of the Argen River, respectively, in samples of the SSB effluent. In addition, sediment samples from the Argen River and tissues of indigenous fish were used for chemical analyses of 33 frequently occurring pollutants by means of gas chromatography. Furthermore, the integrity of the macrozoobenthos community and the fish population were examined at both investigated sampling sites. The chemical analyses revealed a toxic burden with trace substances (originating from traffic and waste water) in fish and sediments from both sampling sites. Fish embryo tests with native sediment and surface water samples resulted in various embryotoxic effects in exposed zebrafish embryos (Fig. 1). In addition, the health condition of the investigated fish species (e.g., severe alterations in the liver and kidney) provided clear evidence of water contamination at both Argen River sites (Fig. 2). At distinct points in time, some parameters (fish development, kidney and liver histopathology) indicated stronger effects at the sampling site downstream of the SSB effluent than at the upstream site. Our results clearly showed that the SSB cannot be assigned as the main source of pollutants that are released into the investigated Argen River section. Moreover, we showed that there is moderate background pollution with substances

Sediment-water interactions affecting dissolved-mercury distributions in Camp Far West Reservoir, California

Science.gov (United States)

Kuwabara, James S.; Alpers, Charles N.; Marvin-DiPasquale, Mark; Topping, Brent R.; Carter, James L.; Stewart, A. Robin; Fend, Steven V.; Parcheso, Francis; Moon, Gerald E.; Krabbenhoft, David P.

2003-01-01

Field and laboratory studies were conducted in April and November 2002 to provide the first direct measurements of the benthic flux of dissolved (0.2-micrometer filtered) mercury species (total and methylated forms) between the bottom sediment and water column at three sampling locations within Camp Far West Reservoir, California: one near the Bear River inlet to the reservoir, a second at a mid-reservoir site of comparable depth to the inlet site, and the third at the deepest position in the reservoir near the dam (herein referred to as the inlet, midreservoir and near-dam sites, respectively; Background, Fig. 1). Because of interest in the effects of historic hydraulic mining and ore processing in the Sierra Nevada foothills just upstream of the reservoir, dissolved-mercury species and predominant ligands that often control the mercury speciation (represented by dissolved organic carbon, and sulfides) were the solutes of primary interest. Benthic flux, sometimes referred to as internal recycling, represents the transport of dissolved chemical species between the water column and the underlying sediment. Because of the affinity of mercury to adsorb onto particle surfaces and to form insoluble precipitates (particularly with sulfides), the mass transport of mercury in mining-affected watersheds is typically particle dominated. As these enriched particles accumulate at depositional sites such as reservoirs, benthic processes facilitate the repartitioning, transformation, and transport of mercury in dissolved, biologically reactive forms (dissolved methylmercury being the most bioavailable for trophic transfer). These are the forms of mercury examined in this study. In contrast to typical scientific manuscripts, this report is formatted in a pyramid-like structure to serve the needs of diverse groups who may be interested in reviewing or acquiring information at various levels of technical detail (Appendix 1). The report enables quick transitions between the initial

Microcosm investigations of stormwater pond sediment toxicity to embryonic and larval amphibians: Variation in sensitivity among species

Energy Technology Data Exchange (ETDEWEB)

Snodgrass, Joel W. [Department of Biological Sciences, Towson University, 8000 York Road, Towson, MD 21252 (United States)], E-mail: jsnodgrass@towson.edu; Casey, Ryan E. [Department of Chemistry, Towson University, 8000 York Road, Towson, MD 21252 (United States); Joseph, Debra; Simon, Judith A. [Department of Biological Sciences, Towson University, 8000 York Road, Towson, MD 21252 (United States)

2008-07-15

Stormwater ponds have become common features of modern development and often represent significant amounts of open space in urbanized areas. Although stormwater ponds may provide habitat for wildlife, factors responsible for producing variation in wildlife use of ponds have received limited attention. To investigate the role of variation in species tolerances of pollutants in structuring pond-breeding amphibian assemblages, we exposed species tolerant (Bufo americanus) and not tolerant (Rana sylvatica) of urbanization to pond sediments in laboratory microcosms. Pond microcosms had elevated sediment metal levels and chloride water concentrations. Among R. sylvatica embryos, exposure to pond sediments resulted in 100% mortality. In contrast, B. americanus embryos and larvae experienced only sublethal effects (i.e., reduced size at metamorphosis) due to pond sediment exposure. Our results suggest variation in pollutant tolerance among early developmental stages of amphibians may act in concert with terrestrial habitat availability to structure amphibian assemblages associated with stormwater ponds. - Variation among species in sensitivity to pollutants can influence stormwater pond amphibian assemblages.

Elucidating Microbial Species-Specific Effects on Organic Matter Transformation in Marine Sediments

Science.gov (United States)

Mahmoudi, N.; Enke, T. N.; Beaupre, S. R.; Teske, A.; Cordero, O. X.; Pearson, A.

2017-12-01

Microbial transformation and decomposition of organic matter in sediments constitutes one of the largest fluxes of carbon in marine environments. Mineralization of sedimentary organic matter by microorganisms results in selective degradation such that bioavailable or accessible compounds are rapidly metabolized while more recalcitrant, complex compounds are preserved and buried in sediment. Recent studies have found that the ability to use different carbon sources appears to vary among microorganisms, suggesting that the availability of certain pools of carbon can be specific to the taxa that utilize the pool. This implies that organic matter mineralization in marine environments may depend on the metabolic potential of the microbial populations that are present and active. The goal of our study was to investigate the extent to which organic matter availability and transformation may be species-specific using sediment from Guaymas Basin (Gulf of California). We carried out time-series incubations using bacterial isolates and sterilized sediment in the IsoCaRB system which allowed us to measure the production rates and natural isotopic signatures (δ13C and Δ14C) of microbially-respired CO2. Separate incubations using two different marine bacterial isolates (Vibrio sp. and Pseudoalteromonas sp.) and sterilized Guaymas Basin sediment under oxic conditions showed that the rate and total quantity of organic matter metabolized by these two species differs. Approximately twice as much CO2 was collected during the Vibrio sp. incubation compared to the Pseudoalteromonas sp. incubation. Moreover, the rate at which organic matter was metabolized by the Vibrio sp. was much higher than the Pseudoalteromonas sp. indicating the intrinsic availability of organic matter in sediments may depend on the species that is present and active. Isotopic analyses of microbially respired CO2 will be used to constrain the type and age of organic matter that is accessible to each species

FARO tests corium-melt cooling in water pool: Roles of melt superheat and sintering in sediment

Energy Technology Data Exchange (ETDEWEB)

Hwang, Gisuk [Department of Mechanical Engineering, Wichita State University, Wichita, KS 67260 (United States); Kaviany, Massoud [Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109 (United States); Division of Advance Nuclear Engineering, POSTECH, Pohang, Gyeongbuk 790-784 (Korea, Republic of); Moriyama, Kiyofumi [Division of Advance Nuclear Engineering, POSTECH, Pohang, Gyeongbuk 790-784 (Korea, Republic of); Park, Hyun Sun, E-mail: hejsunny@postech.ac.kr [Division of Advance Nuclear Engineering, POSTECH, Pohang, Gyeongbuk 790-784 (Korea, Republic of); Hwang, Byoungcheol; Lee, Mooneon; Kim, Eunho; Park, Jin Ho [Division of Advance Nuclear Engineering, POSTECH, Pohang, Gyeongbuk 790-784 (Korea, Republic of); Nasersharifi, Yahya [Department of Mechanical Engineering, Wichita State University, Wichita, KS 67260 (United States)

2016-08-15

Highlights: • The numerical approach for FARO experimental data is suggested. • The cooling mechanism of ex-vessel corium is suggested. • The predicted minimum pool depth for no cake formation is suggested. - Abstract: The FARO tests have aimed at understanding an important severe accident mitigation action in a light water reactor when the accident progresses from the reactor pressure vessel boundary. These tests have aimed to measure the coolability of a molten core material (corium) gravity dispersed as jet into a water pool, quantifying the loose particle diameter distribution and fraction converted to cake under range of initial melt superheat and pool temperature and depth. Under complete hydrodynamic breakup of corium and consequent sedimentation in the pool, the initially superheated corium can result in debris bed consisting of discrete solid particles (loose debris) and/or a solid cake at the bottom of the pool. The success of the debris bed coolability requires cooling of the cake, and this is controlled by the large internal resistance. We postulate that the corium cake forms when there is a remelting part in the sediment. We show that even though a solid shell forms around the melt particles transiting in the water pool due to film-boiling heat transfer, the superheated melt allows remelting of the large particles in the sediment (depending on the water temperature and the transit time) using the COOLAP (Coolability Analysis with Parametric fuel-cooant interaction models) code. With this remelting and its liquid-phase sintering of the non-remelted particles, we predict the fraction of the melt particles converting to a cake through liquid sintering. Our predictions are in good agreement with the existing results of the FARO experiments. We address only those experiments with pool depths sufficient/exceeding the length required for complete breakup of the molten jet. Our analysis of the fate of molten corium aimed at devising the effective

Arsenic Transfer from As-Rich Sediments to River Water in the Presence of Biofilms

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Diego Martiñá Prieto

2016-01-01

Full Text Available The influence of epipsammic biofilms on As release from river sediments was evaluated in a microcosm experiment where biofilms were grown on sediments containing 106 mg kg−1 As, collected in the Anllóns River, and compared with control systems without biofilms. The As transfer to the water column was low (<0.11% of total As in the sediment and was further reduced by 64% in the presence of biofilms. AsV was the predominant species in the overlying water in both systems. AsIII concentration was higher (up to 12% of total dissolved As in the control systems than in the systems with biofilms, where this species was almost absent. This fact is of toxicological relevance due to the usually higher mobility and toxicity of the reduced AsIII species. Control systems exhibited higher As mobility in water, in sulphate solution, and in weak acid medium and higher bioavailability in diffusive gradient in thin films (DGT devices. Arsenic retained by the biofilm was equally distributed between extracellular and intracellular compartments. Inside the cells, significant concentrations of AsIII, monomethylarsonic acid (MMAV, and dimethylarsinic acid (DMAV were detected, suggesting that active methylation (detoxification processes are occurring in the intracellular compartment.

Effects of water stress and high temperature on photosynthetic rates of two species of Prosopis.

Science.gov (United States)

Delatorre, Jose; Pinto, Manuel; Cardemil, Liliana

2008-08-21

The main aim of this research was to compare the photosynthetic responses of two species of Prosopis, Prosopis chilensis (algarrobo) and Prosopis tamarugo (tamarugo) subjected to heat and water stress, to determine how heat shock or water deficit, either individually or combined, affect the photosynthesis of these two species. The photosynthetic rates expressed as a function of photon flow density (PFD) were determined by the O(2) liberated, in seedlings of tamarugo and algarrobo subjected to two water potentials: -0.3 MPa and -2.5 MPa and to three temperatures: 25 degrees C, 35 degrees C and 40 degrees C. Light response curves were constructed to obtain light compensation and light saturation points, maximum photosynthetic rates, quantum yields and dark respiration rates. The photochemical efficiency as the F(v)/F(m) ratio and the amount of RUBISCO were also determined under heat shock, water deficit, and under the combined action of both stress. Photosynthetic rates at a light intensity higher than 500 micromole photons m(-2)s(-1) were not significantly different (P>0.05) between species when measured at 25 degrees C under the same water potential. The maximum photosynthetic rates decreased with temperature in both species and with water deficit in algarrobo. At 40 degrees C and -2.5 MPa, the photosynthetic rate of algarrobo fell to 72% of that of tamarugo. The quantum yield decreased in algarrobo with temperature and water deficit and it was reduced by 50% when the conditions were 40 degrees C and -2.5 MPa. Dark respiration increased by 62% respect to the control at 40 degrees C in tamarugo while remained unchanged in algarrobo. The photochemical efficiency decreased with both, high temperature and water deficit, without differences between species. RUBISCO content increased in algarrobo 35 degrees C. Water deficit reduced the amount of RUBISCO in both species. The results of this work support the conclusion that in both Prosopis species, the interaction between

Laboratory leach tests of phosphate/sulfate waste grout and leachate adsorption tests using Hanford sediment

Energy Technology Data Exchange (ETDEWEB)

Serne, R.J.; Martin, W.J.; McLaurine, S.B.; Airhart, S.P.; LeGore, V.L.; Treat, R.L.

1987-12-01

An assessment of the long-term risks posed by grout disposal at Hanford requires data on the ability of grout to resist leaching of waste species contained in the grout via contact with water that percolates through the ground. Additionally, data are needed on the ability of Hanford sediment (soil) surrounding the grout and concrete vault to retard migration of any wastes released from the grout. This report describes specific laboratory experiments that are producing empirical leach rate data and leachate-sediment adsorption data for Phosphate-Sulfate Waste (PSW) grout. The leach rate and adsorption values serve as inputs to computer codes used to forecast potential risk resulting from the use of ground water containing leached species. In addition, the report discusses other chemical analyses and geochemical computer code calculations that were used to identify mechanisms that control leach rates and adsorption potential. Knowledge of the controlling chemical and physical processes provides technical defensibility for using the empirical laboratory data to extrapolate the performance of the actual grout disposal system to the long time periods of interest. 59 refs., 83 figs., 18 tabs.

Laboratory leach tests of phosphate/sulfate waste grout and leachate adsorption tests using Hanford sediment

International Nuclear Information System (INIS)

Serne, R.J.; Martin, W.J.; McLaurine, S.B.; Airhart, S.P.; LeGore, V.L.; Treat, R.L.

1987-12-01

An assessment of the long-term risks posed by grout disposal at Hanford requires data on the ability of grout to resist leaching of waste species contained in the grout via contact with water that percolates through the ground. Additionally, data are needed on the ability of Hanford sediment (soil) surrounding the grout and concrete vault to retard migration of any wastes released from the grout. This report describes specific laboratory experiments that are producing empirical leach rate data and leachate-sediment adsorption data for Phosphate-Sulfate Waste (PSW) grout. The leach rate and adsorption values serve as inputs to computer codes used to forecast potential risk resulting from the use of ground water containing leached species. In addition, the report discusses other chemical analyses and geochemical computer code calculations that were used to identify mechanisms that control leach rates and adsorption potential. Knowledge of the controlling chemical and physical processes provides technical defensibility for using the empirical laboratory data to extrapolate the performance of the actual grout disposal system to the long time periods of interest. 59 refs., 83 figs., 18 tabs

Water developments and canids in two North American deserts: a test of the indirect effect of water hypothesis.

Directory of Open Access Journals (Sweden)

Lucas K Hall

Full Text Available Anthropogenic modifications to landscapes intended to benefit wildlife may negatively influence wildlife communities. Anthropogenic provisioning of free water (water developments to enhance abundance and distribution of wildlife is a common management practice in arid regions where water is limiting. Despite the long-term and widespread use of water developments, little is known about how they influence native species. Water developments may negatively influence arid-adapted species (e.g., kit fox, Vulpes macrotis by enabling water-dependent competitors (e.g., coyote, Canis latrans to expand distribution in arid landscapes (i.e., indirect effect of water hypothesis. We tested the two predictions of the indirect effect of water hypothesis (i.e., coyotes will visit areas with free water more frequently and kit foxes will spatially and temporally avoid coyotes and evaluated relative use of free water by canids in the Great Basin and Mojave Deserts from 2010 to 2012. We established scent stations in areas with (wet and without (dry free water and monitored visitation by canids to these sites and visitation to water sources using infrared-triggered cameras. There was no difference in the proportions of visits to scent stations in wet or dry areas by coyotes or kit foxes at either study area. We did not detect spatial (no negative correlation between visits to scent stations or temporal (no difference between times when stations were visited segregation between coyotes and kit foxes. Visitation to water sources was not different for coyotes between study areas, but kit foxes visited water sources more in Mojave than Great Basin. Our results did not support the indirect effect of water hypothesis in the Great Basin or Mojave Deserts for these two canids.

Contrasting impacts of light reduction on sediment biogeochemistry in deep- and shallow-water tropical seagrass assemblages (Green Island, Great Barrier Reef).

Science.gov (United States)

Schrameyer, Verena; York, Paul H; Chartrand, Kathryn; Ralph, Peter J; Kühl, Michael; Brodersen, Kasper Elgetti; Rasheed, Michael A

2018-05-01

Seagrass meadows increasingly face reduced light availability as a consequence of coastal development, eutrophication, and climate-driven increases in rainfall leading to turbidity plumes. We examined the impact of reduced light on above-ground seagrass biomass and sediment biogeochemistry in tropical shallow- (∼2 m) and deep-water (∼17 m) seagrass meadows (Green Island, Australia). Artificial shading (transmitting ∼10-25% of incident solar irradiance) was applied to the shallow- and deep-water sites for up to two weeks. While above-ground biomass was unchanged, higher diffusive O 2 uptake (DOU) rates, lower O 2 penetration depths, and higher volume-specific O 2 consumption (R) rates were found in seagrass-vegetated sediments as compared to adjacent bare sand (control) areas at the shallow-water sites. In contrast, deep-water sediment characteristics did not differ between bare sand and vegetated sites. At the vegetated shallow-water site, shading resulted in significantly lower hydrogen sulphide (H 2 S) levels in the sediment. No shading effects were found on sediment biogeochemistry at the deep-water site. Overall, our results show that the sediment biogeochemistry of shallow-water (Halodule uninervis, Syringodium isoetifolium, Cymodocea rotundata and C. serrulata) and deep-water (Halophila decipiens) seagrass meadows with different species differ in response to reduced light. The light-driven dynamics of the sediment biogeochemistry at the shallow-water site could suggest the presence of a microbial consortium, which might be stimulated by photosynthetically produced exudates from the seagrass, which becomes limited due to lower seagrass photosynthesis under shaded conditions. Copyright © 2018 Elsevier Ltd. All rights reserved.

MEASUREMENT OF THE VISCOELASTIC PROPERTIES OF WATER-SATURATED CLAY SEDIMENTS.

Science.gov (United States)

The complex shear modulus of both kaolin -water and bentonite-water mixtures has been determined in the laboratory. The method involved measuring the...range two to forty-three kHz. Dispersed sediments behaved like Newtonian liquids. Undispersed sediments, however, were viscoelastic in character, and...their shear moduli exhibited no dependence on frequency. For undispersed kaolin mixtures, a typical result is (21.6 + i 1.2) x 1,000 dynes per square

Testing lagoonal sediments with early life stages of the copepod Acartia tonsa (Dana): An approach to assess sediment toxicity in the Venice Lagoon

DEFF Research Database (Denmark)

Picone, Marco; Bergamin, Martina; Delaney, Eugenia

2018-01-01

between samples and control) and to investigate the possible correlation with sediment chemistry and physical properties. The results showed that statistical performances of the LDR test with A. tonsa correspond with the outcomes of other tests applied to the sediment-water interface (Strongylocentrotus...

Sediment transport, light and algal growth in the Markermeer : a two-dimensional water quality model for a shallow lake

NARCIS (Netherlands)

Duin, van E.H.S.

1992-01-01

This thesis reports on a study of the water quality in the Markermeer, focusing on the relationships between sediment transport, the light field and the growth of Oscillatoria agardhii . The study comprises two aspects: an extensive data collection program with the data

Reactive transport modeling of nitrogen in Seine River sediments

Science.gov (United States)

Akbarzadeh, Z.; Laverman, A.; Raimonet, M.; Rezanezhad, F.; Van Cappellen, P.

2016-02-01

Biogeochemical processes in sediments have a major impact on the fate and transport of nitrogen (N) in river systems. Organic matter decomposition in bottom sediments releases inorganic N species back to the stream water, while denitrification, anammox and burial of organic matter remove bioavailable N from the aquatic environment. To simulate N cycling in river sediments, a multi-component reactive transport model has been developed in MATLAB®. The model includes 3 pools of particulate organic N, plus pore water nitrate, nitrite, nitrous oxide and ammonium. Special attention is given to the production and consumption of nitrite, a N species often neglected in early diagenetic models. Although nitrite is usually considered to be short-lived, elevated nitrite concentrations have been observed in freshwater streams, raising concerns about possible toxic effects. We applied the model to sediment data sets collected at two locations in the Seine River, one upstream, the other downstream, of the largest wastewater treatment plant (WWTP) of the Paris conurbation. The model is able to reproduce the key features of the observed pore water depth profiles of the different nitrogen species. The modeling results show that the presence of oxygen in the overlying water plays a major role in controlling the exchanges of nitrite between the sediments and the stream water. In August 2012, sediments upstream of the WWTP switch from being a sink to a source of nitrite as the overlying water becomes anoxic. Downstream sediments remain a nitrite sink in oxic and anoxic conditions. Anoxic bottom waters at the upstream location promote denitrification, which produces nitrite, while at the downstream site, anammox and DNRA are important removal processes of nitrite.

Toxicities of sediments below 10 effluent outfalls to near-coastal areas of the Gulf of Mexico

International Nuclear Information System (INIS)

Lewis, M.; Weber, D.; Stanley, R.

1995-01-01

The chemical quality and toxicities of sediments collected in the receiving waters below 10 wastewater outfalls to Northwest Florida coastal areas were evaluated at multiple stations during 1994--1996. Eight types of toxicity tests using 11 test species were used to assess acute and chronic toxicity of the sediments collected below industrial, municipal, power generation and pulp mill outfalls. The primary objectives of the study were to evaluate the relative ability of different assessment procedures to detect toxicity and to provide some much-needed perspective on the impact of major point sources on sediment quality in Gulf of Mexico estuaries. The major chemical contaminants were heavy metals and PAHs. Acute and chronic toxicities were noted. Results of tests with sediment collected at the same location but several months later often differed. The most sensitive species were mysids and an estuarine amphipod. The least sensitive species were fish and macrophyte seedlings. There was poor correlation of effluent toxicity to sediment toxicity in the receiving water. Toxicity of the effluents was greater than that of the sediments. Overall, the unavailability of relevant chronic toxicity methods, uncertain criteria for choice of control stations, lack of guidance on frequency of testing and the dynamic physical and chemical characteristics of sediments are factors that need consideration if sediment monitoring is to be part of the NPDES regulatory process

Lethal and sublethal responses to a sediment bound toxicant by two oligochaetes from Lake Michigan: stylodrilus heringianus and limnodrilus hoffmeisteri

International Nuclear Information System (INIS)

Keilty, T.J.

1987-01-01

Short-term lethal, and short and long-term sublethal responses by Stylodrilus heringianus (Lumbriculidae) and Limnodrilus hoffmeisteri (Tubificidae) to sediments dosed with endrin were measured in single and mixed species tests. Ninety-six hour LC 50 values were 2588 +/- 1974 and 2757 +/- 995 ug/g dry weight sediment for S. heringianus and L. hoffmeisteri respectively. Ninety-six hour EC 50 burrowing avoidance values (concentration where 50% do not burrow) were one to two orders of magnitude lower than the LC 50 's. Short-term mixed species LC 50 data suggested that L. hoffmeisteri may benefit from the presence of S. heringianus. Long-term sublethal responses were quantified by measuring sediment reworking rates (the rate at which subsurface sediments are egested at the surface and re-buried) in laboratory microcosms. Rates were determined by monitoring a gamma-emitting 137 Cesium marker layer with a well-collimated NaI detector. Sediment endrin concentrations ranged from 3 ng/g to 82 ug/g in six 1300 hour experiments. For S. heringianus, reworking rates were stimulated at low concentrations during the first half of experiments, followed by gradual decreases relative to controls. Stimulation of L. hoffmeisteri reworking was not observed. At high concentrations, early reworking rates were reduced for both species, followed by dramatic decreases later on. In mixed species experiments at high concentrations, the presence of S. heringianus enhanced the reworking of L. hoffmeisteri, although the reverse was not observed. Decreased mortality and increased post experimental dry weights of L. hoffmeisteri in mixed, relative to single species tests were also observed. Generally, post experimental worm weights were inversely related to sediment endrin loads, and bioconcentration factors for S. heringianus (10-40) were approximately fourfold that of L. hoffmeisteri (1-10)

Evaluation of experimental studies on technetium transfers to sediments and benthic marine species, and comparison with in situ data

Energy Technology Data Exchange (ETDEWEB)

Aprosi, G [Electricite de France, 78 - Chatou; Masson, M [Commisariat a l' Energie Atomique, Institut de Protection et de Surete Nucleaire, 50 - Cherbourg (France)

1984-01-01

To obtain basic information for the evaluation of the radiological impact of technetium (Tc) on the marine environment, investigations are performed by different laboratories. Technetium is not a natural element and the main source of production is the nuclear fuel cycle. Under anoxic conditions, in presence of reducing sediments, the distribution coefficients are very high (Ksub(D)=10/sup 3/). Concentration factors from water to species are mostly very low (FC 1 to 10); however, concentration factors up to 1000 have been observed for a few species such as macrophytic brown algae, worms and lobster. Biochemical analysis shows that Tc is bound with protein. The transfer factors between sediment and species are very low (FT<0,5). The biological half-life (Tb) was determined in some marine organisms which had accumulated the radionuclide from water-contamined food or from sediments. The loss is biphasic in storage organs (liver and kidney); uptake in the edible parts is low. Among the parameters studied (light for algae, physico-chemical form of Tc, salinity and temperature) only light and the physico-chemical forms have an effect on the accumulation of technetium. Analyses of /sup 99/Tc concentrations in species collected near the La Hague and Windscale (Sellafield) reprocessing plants confirm the experimental studies. Since sea water is likely to be an oxidant environment, technetium appears as a conservative element.

Bioavailability, ecotoxicity, and geological characteristics of trace lead in sediments from two sites on Negro River, Uruguay, South America.

Science.gov (United States)

Míguez, Diana M; Huertas, Raquel; Carrara, María V; Carnikián, Agustín; Bouvier, María E; Martínez, María J; Keel, Karen; Pioda, Carolina; Darré, Elena; Pérez, Ramiro; Viera, Santiago; Massa, Enrique

2012-04-01

Bioassays of two sites along the Rio Negro in Uruguay indicate ecotoxicity, which could be attributable to trace concentrations of lead in river sediments. Monthly samples at two sites at Baygorria and Bonete locations were analyzed for both particle size and lead. Lead was determined by atomic spectrometry in river water and sediment and particle size by sieving and sedimentation. Data showed that Baygorria's sediments have greater percentage of clay than Bonete's (20.4 and 5.8%, respectively). Lead was measurable in Baygorria's sediments, meanwhile in Bonete's, it was always below the detection limit. In water samples, lead was below detection limit at both sites. Bioassays using sub-lethal growth and survival test with Hyalella curvispina amphipod, screening with bioluminescent bacteria Photobacterium leiognathi, and acute toxicity bioassay with Pimephales promelas fish indicated toxicity at Baygorria, with much less effect at Bonete. Even though no lethal effects could be demonstrated, higher sub-lethal toxicity was found in samples from Baygorria site, showing a possible concentration of the contaminant in the clay fraction.

Testing lagoonal sediments with early life stages of the copepod Acartia tonsa (Dana): An approach to assess sediment toxicity in the Venice Lagoon.

Science.gov (United States)

Picone, Marco; Bergamin, Martina; Delaney, Eugenia; Ghirardini, Annamaria Volpi; Kusk, Kresten Ole

2018-01-01

The early-life stages of development of the calanoid copepod Acartia tonsa from egg to copepodite I is proposed as an endpoint for assessing sediment toxicity by exposing newly released eggs directly onto the sediment-water interface. A preliminary study of 5 sediment samples collected in the lagoon of Venice highlighted that the larval development rate (LDR) and the early-life stages (ELS) mortality endpoints with A. tonsa are more sensitive than the standard amphipod mortality test; moreover LDR resulted in a more reliable endpoint than ELS mortality, due to the interference of the sediment with the recovery of unhatched eggs and dead larvae. The LDR data collected in a definitive study of 48 sediment samples from the Venice Lagoon has been analysed together with the preliminary data to evaluate the statistical performances of the bioassay (among replicate variance and minimum significant difference between samples and control) and to investigate the possible correlation with sediment chemistry and physical properties. The results showed that statistical performances of the LDR test with A. tonsa correspond with the outcomes of other tests applied to the sediment-water interface (Strongylocentrotus purpuratus embryotoxicity test), sediments (Neanthes arenaceodentata survival and growth test) and porewater (S. purpuratus); the LDR endpoint did, however, show a slightly higher variance as compared with other tests used in the Lagoon of Venice, such as 10-d amphipod lethality test and larval development with sea urchin and bivalves embryos. Sediment toxicity data highlighted the high sensitivity and the clear ability of the larval development to discriminate among sediments characterized by different levels of contamination. The data of the definitive study evidenced that inhibition of the larval development was not affected by grain-size and the organic carbon content of the sediment; in contrast, a strong correlation between inhibition of the larval development

Preparation and characterization of nickel-spiked freshwater sediments for toxicity tests: toward more environmentally realistic nickel partitioning

Science.gov (United States)

Brumbaugh, William G.; Besser, John M.; Ingersoll, Christopher G.; May, Thomas W.; Ivey, Chris D.; Schlekat, Christian E.; Garman, Emily R.

2013-01-01

Two spiking methods were compared and nickel (Ni) partitioning was evaluated during a series of toxicity tests with 8 different freshwater sediments having a range of physicochemical characteristics. A 2-step spiking approach with immediate pH adjustment by addition of NaOH at a 2:1 molar ratio to the spiked Ni was effective in producing consistent pH and other chemical characteristics across a range of Ni spiking levels. When Ni was spiked into sediment having a high acid-volatile sulfide and organic matter content, a total equilibration period of at least 10 wk was needed to stabilize Ni partitioning. However, highest spiking levels evidently exceeded sediment binding capacities; therefore, a 7-d equilibration in toxicity test chambers and 8 volume-additions/d of aerobic overlying water were used to avoid unrealistic Ni partitioning during toxicity testing. The 7-d pretest equilibration allowed excess spiked Ni and other ions from pH adjustment to diffuse from sediment porewater and promoted development of an environmentally relevant, 0.5- to 1-cm oxic/suboxic sediment layer in the test chambers. Among the 8 different spiked sediments, the logarithm of sediment/porewater distribution coefficient values (log Kd) for Ni during the toxicity tests ranged from 3.5 to 4.5. These Kd values closely match the range of values reported for various field Ni-contaminated sediments, indicating that testing conditions with our spiked sediments were environmentally realistic.

Hydrological Conditions Affect the Interspecific Interaction between Two Emergent Wetland Species

Directory of Open Access Journals (Sweden)

Jian Zhou

2018-01-01

Full Text Available Hydrological conditions determine the distribution of plant species in wetlands, where conditions such as water depth and hydrological fluctuations are expected to affect the interspecific interactions among emergent wetland species. To test such effects, we conducted a greenhouse experiment with three treatment categories, interspecific interaction (mixed culture or monoculture, water depth (10 or 30 cm depth, and hydrological fluctuation (static or fluctuating water level, and two common emergent wetland plant species, Scirpus planiculumis Fr. (Cyperaceae and Phragmites australis var. baiyangdiansis (Gramineae. An increase in the water depth significantly restrained the growth of both S. planiculumis and P. australis, while hydrological fluctuations did not obviously alter the growth of either species. In addition, both water depth and hydrological fluctuations significantly affected the interspecific interaction between these two wetland species. P. australis benefited from interspecific interaction under increasing water depth and hydrological fluctuations, and the RII values were clearly positive for plants grown at a water depth that fluctuated around 30 cm. The results may have some implications for understanding how S. planiculumis and P. australis, as well as wetland communities, respond to the natural variation or human modification of hydrological conditions.

Heat stress of two tropical seagrass species during low tides

DEFF Research Database (Denmark)

Pedersen, Ole; Colmer, Timothy D.; Borum, Jens

2016-01-01

Seagrasses grow submerged in aerated seawater but often in low O2 sediments. Elevated temperatures and low O2 are stress factors. Internal aeration was measured in two tropical seagrasses, Thalassia hemprichii and Enhalus acoroides, growing with extreme tides and diel temperature amplitudes......), the high temperatures and reduced CO2 would have diminished PN, whereas RD increased (Q10 of 2.0-2.7) above that at 33°C (0.45 and 0.33 μmol O2 m-2 s-1, respectively). During night-time low tides, O2 declined resulting in shoot base anoxia in both species, but incoming water containing c. 20 kPa O2...

Mercury in water and bottom sediments from a mexican reservoir

International Nuclear Information System (INIS)

Avila Perez, P.; Zarazua Ortega, G.; Barcelo Quintal, D.; Rosas, P.; Diazdelgado, C.

2001-01-01

The Lerma-Santiago river's source is located in the State of Mexico. Its drainage basin occupies an area of 129,632 km2. The river receives urban wastewater discharges from 29 municipalities, as well as industrial water discharges, both treated and untreated, mainly from the industrial zones of Toluca, Lerma, Ocoyoacac, Santiago Tianguistengo, Pasteje and Atlacomulco. It is estimated that during a year, the stream receives 536 x 106 m3 of waste waters, which carries 350,946 ton of organic load; 33% of these waste waters come from urban discharges, and 67% originate from industrial discharges. The Jose Antonio Alzate Reservoir fed by the Lerma river is the first significant water reservoir downstream of the main industrial areas in the State of Mexico and both are considered the most contaminated water bodies in the State of Mexico. Mercury concentrations in water and bottom sediments in the Jose Antonio Alzate Reservoir were determined in 6 different sampling zones over a 1-year period. Mercury was measured by instrumental neutron activation analysis (INAA) and irradiated with a thermal neutron flux of 9 x 1012 n. cm-2 s-1 for a period of 26 hours. High variations of mercury concentrations in water in both, soluble and suspended forms, were observed to depend on the sampling season. During the rainy season, rain events contribute with a substantial water volume to modify physicochemical parameters like pH, which dilute chemical species in the Alzate Reservoir. There are evidence that in the Jose Antonio Alzate reservoir, sedimentation and adsorption act as a natural cleaning process, decreasing the dissolved concentrations and increasing the metallic content of the sediments. A negative gradient was identified for mercury concentrations, from the Lerma river inlet to Alzate Reservoir dam, which demonstrates the considerable influence of the Lerma river inlet. This gradient also proves the existence of a metal recycling process between water and sediment, while the

Radon-222 and radium-226 in southeastern Bering Sea shelf waters and sediment

International Nuclear Information System (INIS)

Glover, D.M.; Reeburgh, W.S.

1987-01-01

Radon-222 and 226 Ra activities were measured in the waters and sediment of the southeastern Bering Sea shelf to evaluate the use of radon as a tracer of gas exchange, water column mixing and sediment-water exchange. Cross-shelf distributions of 222 Rn and 226 Ra are presented. Gas transfer coefficients were estimated using near-surface 222 Rn deficiency measurements. A statistically significant linear relationship between averaged wind speed and transfer coefficient was found. Vertical eddy diffusivities were evaluated by applying a one-dimensional model to near-bottom excess 222 Rn distributions; these diffusivities were compared to independently determined values. The one-dimensional model applied to the near-bottom 222 Rn data was found to be inadequate and a two-dimensional model was applied to improve the fit between model and data. Exchange across the sediment-water interface was computed from the deficiency of 222 Rn measured in sediment cores, standing crop estimates of excess 222 Rn in the water column and 222 Rn production rates of sediment surface grab samples. Biological irrigation of the sediments appeared to be the primary exchange mechanism between the sediment and water columns. Distributions in the water column showed finestructure reported previously and suggested biological removal of 226 Ra. (author)

The Effect of Landuse and Other External Factors on Water Quality Within two Creeks in Northern Kentucky

Science.gov (United States)

Boateng, S.

2006-05-01

The purpose of this study was to monitor the water quality in two creeks in Northern Kentucky. These are the Banklick Creek in Kenton County and the Woolper Creek in Boone County, Kentucky. The objective was to evaluate the effect of landuse and other external factors on surface water quality. Landuse within the Banklick watershed is industrial, forest and residential (urban) whereas that of Woolper Creek is agricultural and residential (rural). Two testing sites were selected along the Banklick Creek; one site was upstream the confluence with an overflow stream from an adjacent lake; the second site was downstream the confluence. Most of the drainage into the lake is over a near-by industrial park and the urban residential areas of the cities of Elsmere and Erlanger, Kentucky. Four sampling locations were selected within the Woolper Creek watershed to evaluate the effect of channelization and subsequent sedimentation on the health of the creek. Water quality parameters tested for include dissolved oxygen, phosphates, chlorophyll, total suspended sediments (TSS), pH, oxidation reduction potential (ORP), nitrates, and electrical conductivity. Sampling and testing were conducted weekly and also immediately after storm events that occurred before the regular sampling dates. Sampling and testing proceeded over a period of 29 weeks. Biological impact was determined, only in Woolper Creek watershed, by sampling benthic macroinvertebrates once every four weeks. The results showed significant differences in the water quality between the two sites within the Banklick Creek. The water quality may be affected by the stream overflow from the dammed lake. Also, channelization in the Woolper Creek seemed to have adverse effects on the water quality. A retention pond, constructed to prevent sediments from flowing into the Woolper Creek, did not seem to be effective. This is because the water quality downstream of the retention pond was significantly worse than that of the

Americium and plutonium in water, biota, and sediment from the central Oregon coast

International Nuclear Information System (INIS)

Nielsen, R.D.

1982-06-01

Plutonium-239, 240 and americium-241 were measured in the mussel Mytilus californianus from the region of Coos Bay, OR. The flesh of this species has a plutonium concentration of about 90 fCi/kg, and an Am-241/Pu-239, 240 ratio that is high relative to mixed fallout, ranging between two and three. Transuranic concentrations in sediment, unfiltered water, and filterable particulates were also measured; none of these materials has an Am/Pu ratio as greatly elevated as the mussels, and there is no apparent difference in the Am/Pu ratio of terrestrial runoff and coastal water. Sediment core profiles do not allow accumulation rates or depositional histories to be identified, but it does not appear that material characterized by a high Am/Pu ratio has ever been introduced to this estuary. Other bivalves (Tresus capax and Macoma nasuta) and a polychaete (Abarenicola sp.) do not have an elevated Am/Pu ratio, although the absolute activity of plutonium in the infaunal bivalves is roughly four times that in the mussels

Modelling of flow and settling in storm water sedimentation tanks

NARCIS (Netherlands)

Kluck, J.

1994-01-01

In the near future in the Netherlands many reservoirs will have to be built to abate the pollution of the surface water by overflowing storm water from combined sewer systems [Kluck, 1992-a]. These reservoirs, called storm water sedimentation tanks, reduce the pollution in two ways. The most

Report on water quality, sediment and water chemistry data for water and sediment samples collected from source areas to Melton Hill and Watts Bar reservoirs

International Nuclear Information System (INIS)

Tomaszewski, T.M.; Bruggink, D.J.; Nunn, D.L.

1995-01-01

Contamination of surface water and sediments in the Clinch River and Watts Bar Reservoir (CR/WBR) system as a result of past and present activities by the US Department of Energy (DOE) on the Oak Ridge Reservation (ORR) and also activities by non-ORR facilities are being studied by the Clinch River Environmental Restoration Program (CR-ERP). Previous studies have documented the presence of heavy metals, organics, and radionuclides in the sediments of reservoirs in the vicinity. In support of the CR-ERP, during the summer of 1991, TVA collected and evaluated water and sediment samples from swimming areas and municipal water intakes on Watts Bar Reservoir, Melton Hill Reservoir and Norris Reservoir, which was considered a source of less-contaminated reference or background data. Despite the numerous studies, until the current work documented by this report, relatively few sediment or water samples had been collected by the CR-ERP in the immediate vicinity of contaminant point sources. This work focused on water and sediment samples taken from points immediately downstream from suspected effluent point sources both on and off the ORR. In August and September, 1994, TVA sampled surface water and sediment at twelve locations in melton Hill and Watts Bar Reservoirs

Sediment and Nutrient Sources as well as Interspecific Competition Control Growth of 2 Common Species of Coral Reef Macroalgae

Science.gov (United States)

Moore, T.; Fong, P.; Cuker, B.

2016-02-01

Aquatic communities worldwide are increasingly subjected to multiple anthropogenic stressors that often result in shifts in structure and function. On coral reefs, human impacts have been associated with phase-shifts from coral to algal domination. We hypothesized that the proliferation of these algal communities, especially on fringing reefs, may be facilitated by human alterations in nutrient enrichment and input of sediments from developed watersheds, which may also influence competitive outcomes among dominant algal species. To evaluate how changes in these abiotic stressors as well as competition may affect the growth of 2 common species of calcifying coral reef algae, Galaxaura fasciculata and Padina boryana, we conducted 3 separate 2 factor mesocosm experiments modeling fringing reefs in Moorea, French Polynesia. In the first experiment, we varied sediment source (marine vs. terrestrial) and water column nutrients (ambient vs. enriched) for each species separately and measured growth after 7 days. While both algae grew faster in enriched compared to ambient nutrients, P. boryana performed best with marine sediment (+27% change in biomass) and G. fasciculata with terrestrial sediment (+14% change in biomass). Next, we varied sediment source (as above) as well as sediment nutrients (ambient/enriched) for each species. While P. boryana lost 44% biomass in the eutrophic terrestrial sediment treatment, G. fasciculata performed the best and gained 19% biomass. Finally, we varied competition (alone/together) and terrestrial sediment nutrients (ambient/enriched). Over the 7 day period, P. boryana lost 64% biomass when in competition with G. fasciculata in the enriched treatment while G. fasciculata gained 38% biomass when in competition with P. boryana in the ambient treatment. These results indicate that, while growth of both species of macroalgae was regulated by nutrients, sediments, and competition, each responded uniquely to these controlling factors.

Fate of isotopically labeled zinc oxide nanoparticles in sediment and effects on two endobenthic species, the clam Scrobicularia plana and the ragworm Hediste diversicolor.

Science.gov (United States)

Buffet, Pierre-Emmanuel; Amiard-Triquet, Claude; Dybowska, Agnieszka; Risso-de Faverney, Christine; Guibbolini, Marielle; Valsami-Jones, Eugénia; Mouneyrac, Catherine

2012-10-01

Although it is reported that metal and metal oxide nanoparticles, which are among the most rapidly commercialized materials, can cause toxicity to organisms, their fate in the environment and toxicity to marine organisms are not well understood. In this study, we used a stable isotope labelling approach to trace the fate of nanoparticles (NPs) in sediments and also investigated bio-uptake in two estuarine intra-sedimentary invertebrates Scrobicularia plana and Nereis diversicolor. We selected exposure to 3 mg kg(-1) sediment ZnO NPs since this level is a realistic prediction of the environmental concentration in sediments. 67ZnO NPs (DLS: 21-34 nm, positively charged: 31.3 mV) suspensions were synthesised in diethylene glycol (DEG). We explored the fate of 67ZnO NPs in sediment, 67Zn bioaccumulation and the biochemical (biomarkers of defence and damage) and behavioural (burrowing kinetics and feeding rates) biomarkers in both species to 67ZnO NPs and DEG on its own during a 16 d laboratory exposure. After exposure, 67Zn concentrations in sediment showed higher levels in the upper section (1cm: 2.59 mg kg(-1)) decreasing progressively (2 cm: 1.63 mg kg(-1), 3 cm: 0.90 mg kg(-1), 4 cm: 0.67 mg kg(-1)) to a minimum value at the bottom (5 cm: 0.31 mg kg(-1)). 67Zn bioaccumulation was observed in both organisms exposed to 67ZnO NPs in DEG but no major inter-species differences were found. At the biochemical level, 67ZnO NPs exposure significantly induced increased glutathione-S-transferase activity in worms and catalase activity in clams whereas superoxide dismutase activity and thiobarbituric acid reactive substance levels were not affected in any species. Exposure to DEG on its own leads to a significant increase of metallothionein-like protein levels in clams compared with those exposed to 67ZnO NPs or controls. Burrowing behaviour as well as feeding rate were significantly impaired in both species exposed to 67ZnO NPs. Concerning exposure to DEG on its own

Prospective Environmental Risk Assessment for Sediment-Bound Organic Chemicals: A Proposal for Tiered Effect Assessment.

Science.gov (United States)

Diepens, Noël J; Koelmans, Albert A; Baveco, Hans; van den Brink, Paul J; van den Heuvel-Greve, Martine J; Brock, Theo C M

A broadly accepted framework for prospective environmental risk assessment (ERA) of sediment-bound organic chemicals is currently lacking. Such a framework requires clear protection goals, evidence-based concepts that link exposure to effects and a transparent tiered-effect assessment. In this paper, we provide a tiered prospective sediment ERA procedure for organic chemicals in sediment, with a focus on the applicable European regulations and the underlying data requirements. Using the ecosystem services concept, we derived specific protection goals for ecosystem service providing units: microorganisms, benthic algae, sediment-rooted macrophytes, benthic invertebrates and benthic vertebrates. Triggers for sediment toxicity testing are discussed.We recommend a tiered approach (Tier 0 through Tier 3). Tier-0 is a cost-effective screening based on chronic water-exposure toxicity data for pelagic species and equilibrium partitioning. Tier-1 is based on spiked sediment laboratory toxicity tests with standard benthic test species and standardised test methods. If comparable chronic toxicity data for both standard and additional benthic test species are available, the Species Sensitivity Distribution (SSD) approach is a more viable Tier-2 option than the geometric mean approach. This paper includes criteria for accepting results of sediment-spiked single species toxicity tests in prospective ERA, and for the application of the SSD approach. We propose micro/mesocosm experiments with spiked sediment, to study colonisation success by benthic organisms, as a Tier-3 option. Ecological effect models can be used to supplement the experimental tiers. A strategy for unifying information from various tiers by experimental work and exposure-and effect modelling is provided.

Model testing of radioactive contamination by {sup 90}Sr, {sup 137}Cs and {sup 239,240}Pu of water and bottom sediments in the Techa River (Southern Urals, Russia)

Energy Technology Data Exchange (ETDEWEB)

Kryshev, I.I. [Scientific and Production Association ' Typhoon' , 82 Lenin Ave., Obninsk, Kaluga Region, 249038 (Russian Federation)], E-mail: ecomod@obninsk.com; Boyer, P.; Monte, L.; Brittain, J.E.; Dzyuba, N.N.; Krylov, A.L.; Kryshev, A.I.; Nosov, A.V.; Sanina, K.D.; Zheleznyak, M.I. [Scientific and Production Association ' Typhoon' , 82 Lenin Ave., Obninsk, Kaluga Region, 249038 (Russian Federation)

2009-03-15

This paper presents results of testing models for the radioactive contamination of river water and bottom sediments by {sup 90}Sr, {sup 137}Cs and {sup 239,240}Pu. The scenario for the model testing was based on data from the Techa River (Southern Urals, Russia), which was contaminated as a result of discharges of liquid radioactive waste into the river. The endpoints of the scenario were model predictions of the activity concentrations of {sup 90}Sr, {sup 137}Cs and {sup 239,240}Pu in water and bottom sediments along the Techa River in 1996. Calculations for the Techa scenario were performed by six participant teams from France (model CASTEAUR), Italy (model MARTE), Russia (models TRANSFER-2, CASSANDRA, GIDRO-W) and Ukraine (model RIVTOX), all using different models. As a whole, the radionuclide predictions for {sup 90}Sr in water for all considered models, {sup 137}Cs for MARTE and TRANSFER-2, and {sup 239,240}Pu for TRANSFER-2 and CASSANDRA can be considered sufficiently reliable, whereas the prediction for sediments should be considered cautiously. At the same time the CASTEAUR and RIVTOX models estimate the activity concentrations of {sup 137}Cs and {sup 239,240}Pu in water more reliably than in bottom sediments. The models MARTE ({sup 239,240}Pu) and CASSANDRA ({sup 137}Cs) evaluated the activity concentrations of radionuclides in sediments with about the same agreement with observations as for water. For {sup 90}Sr and {sup 137}Cs the agreement between empirical data and model predictions was good, but not for all the observations of {sup 239,240}Pu in the river water-bottom sediment system. The modelling of {sup 239,240}Pu distribution proved difficult because, in contrast to {sup 137}Cs and {sup 90}Sr, most of models have not been previously tested or validated for plutonium.

Textural features of the beach sediments of Wast Water Lake, Northwest England

Directory of Open Access Journals (Sweden)

Bala Emilia

2016-06-01

Full Text Available This study is dedicated to Wast Water Lake (Northwest England, Great Britain and the character of its beach sediments. The aim of the study is to identify the textural features of the lake’s beach sediments based on two methods. The first is a granulometric analysis and the second a pebble shape analysis according to Zingg (1935 and Sneed & Folk (1958. Both analyses were carried out for all of the lake’s accessible beaches and the cliffs adjacent to them. The transport and deposition history of the examined sediments was identified through field research and laboratory analysis. The results show that the textural features of the sediments at Wast Water are more often typical of a fluvial environment, rather than having been changed by lacustrine water movements.

18O/16O ratios of the pore water of Baltic Sea sediments

International Nuclear Information System (INIS)

Foerstel, H.

1983-01-01

Two cores of Baltic Sea sediment were collected in 1975. The 18 O/ 16 O ratio of the water enclosed in the sediment (pore water) was measured after the separation of the liquid from the solid phase. The results may support the discussion about the history of the Baltic Sea. At the top of the core the 18 O/ 16 O ratio of the water represents the oxygen isotope composition of the sea water above. Towards the deeper parts of the sediment, independently of the salt content, the 18 O/ 16 O ratio decreases towards values observed in the precipitation of the surrounding land areas. (author)

Variability of sediment-contact tests in freshwater sediments with low-level anthropogenic contamination - Determination of toxicity thresholds

International Nuclear Information System (INIS)

Hoess, S.; Ahlf, W.; Fahnenstich, C.; Gilberg, D.; Hollert, H.; Melbye, K.; Meller, M.; Hammers-Wirtz, M.; Heininger, P.; Neumann-Hensel, H.; Ottermanns, R.; Ratte, H.-T.

2010-01-01

Freshwater sediments with low levels of anthropogenic contamination and a broad range of geochemical properties were investigated using various sediment-contact tests in order to study the natural variability and to define toxicity thresholds for the various toxicity endpoints. Tests were performed with bacteria (Arthrobacter globiformis), yeast (Saccharomyces cerevisiae), nematodes (Caenorhabditis elegans), oligochaetes (Lumbriculus variegatus), higher plants (Myriophyllum aquaticum), and the eggs of zebrafish (Danio rerio). The variability in the response of some of the contact tests could be explained by particle size distribution and organic content. Only for two native sediments could a pollution effect not be excluded. Based on the minimal detectable difference (MDD) and the maximal tolerable inhibition (MTI), toxicity thresholds (% inhibition compared to the control) were derived for each toxicity parameter: >20% for plant growth and fish-egg survival, >25% for nematode growth and oligochaete reproduction, >50% for nematode reproduction and >60% for bacterial enzyme activity. - Sediment-contact tests require toxicity thresholds based on their variability in native sediments with low-level contamination.

Variability of sediment-contact tests in freshwater sediments with low-level anthropogenic contamination - Determination of toxicity thresholds

Energy Technology Data Exchange (ETDEWEB)

Hoess, S., E-mail: hoess@ecossa.d [Ecossa, Giselastr. 6, 82319 Starnberg (Germany); Institute of Biodiversity - Network (IBN), Dreikronengasse 2, 93047 Regensburg (Germany); Ahlf, W., E-mail: ahlf@tu-harburg.d [Institute of Environmental Technology and Energy Economics, Technical University Hamburg-Harburg, Eissendorfer Str. 40, 21071 Hamburg (Germany); Fahnenstich, C. [Institute of Environmental Technology and Energy Economics, Technical University Hamburg-Harburg, Eissendorfer Str. 40, 21071 Hamburg (Germany); Gilberg, D., E-mail: d-gilberg@ect.d [ECT Oekotoxikologie, Boettgerstr. 2-14, 65439 Floersheim (Germany); Hollert, H., E-mail: henner.hollert@bio5.rwth-aachen.d [Department of Ecosystem Analysis, Institute for Environmental Research (Biology 5), RWTH Aachen University, Worringerweg 1, 52074 Aachen (Germany); Melbye, K. [Dr. Fintelmann and Dr. Meyer, Mendelssohnstr. 15D, 22761 Hamburg (Germany); Meller, M., E-mail: m-meller@ecotox-consult.d [ECT Oekotoxikologie, Boettgerstr. 2-14, 65439 Floersheim (Germany); Hammers-Wirtz, M., E-mail: hammers-wirtz@gaiac.rwth-aachen.d [Research Institute for Ecosystem Analysis and Assessment (gaiac), RWTH Aachen University, Worringerweg 1, 52056 Aachen (Germany); Heininger, P., E-mail: heininger@bafg.d [Federal Institute of Hydrology (BfG), Am Mainzer Tor 1, 56070 Koblenz (Germany); Neumann-Hensel, H., E-mail: hensel@fintelmann-meyer.d [Dr. Fintelmann and Dr. Meyer, Mendelssohnstr. 15D, 22761 Hamburg (Germany); Ottermanns, R., E-mail: ottermanns@bio5.rwth-aachen.d [Chair for Environmental Biology and Chemodynamics, Institute for Environmental Research (Biology 5), RWTH Aachen University, Worringerweg 1, 52074 Aachen (Germany); Ratte, H.-T., E-mail: toni.ratte@bio5.rwth-aachen.d [Chair for Environmental Biology and Chemodynamics, Institute for Environmental Research (Biology 5), RWTH Aachen University, Worringerweg 1, 52074 Aachen (Germany)

2010-09-15

Freshwater sediments with low levels of anthropogenic contamination and a broad range of geochemical properties were investigated using various sediment-contact tests in order to study the natural variability and to define toxicity thresholds for the various toxicity endpoints. Tests were performed with bacteria (Arthrobacter globiformis), yeast (Saccharomyces cerevisiae), nematodes (Caenorhabditis elegans), oligochaetes (Lumbriculus variegatus), higher plants (Myriophyllum aquaticum), and the eggs of zebrafish (Danio rerio). The variability in the response of some of the contact tests could be explained by particle size distribution and organic content. Only for two native sediments could a pollution effect not be excluded. Based on the minimal detectable difference (MDD) and the maximal tolerable inhibition (MTI), toxicity thresholds (% inhibition compared to the control) were derived for each toxicity parameter: >20% for plant growth and fish-egg survival, >25% for nematode growth and oligochaete reproduction, >50% for nematode reproduction and >60% for bacterial enzyme activity. - Sediment-contact tests require toxicity thresholds based on their variability in native sediments with low-level contamination.

Speciation of As(III) and As(V) in water and sediment using reverse-phase ion-pair high-performance liquid chromatography-neutron activation analysis (HPLC-NAA).

Science.gov (United States)

Tulasi, Delali; Adotey, Dennis; Affum, Andrews; Carboo, Derick; Serfor-Armah, Yaw

2013-10-01

Total As content and the As species distribution in water and sediments from the Kwabrafo stream, a major water body draining the Obuasi gold mining community in southwestern Ghana, have been investigated. Total As content was determined by instrumental neutron activation analysis (INAA). Ion-pair reverse phase high-performance liquid chromatography-neutron activation analysis (HPLC-NAA) was used for speciation of As species. Solid phase extraction with phosphate buffer was used to extract soluble As species from lyophilized sediment. The mass balance after phosphate extraction of soluble As species in sediment varied from 89 to 96 %. Compositionally appropriate reference material International Atomic Energy Agency (IAEA)-Lake Sediment (SL)-1 was used to check the validity of INAA method for total As determination. The measured values are in good agreement with the IAEA recommended value and also within the 95 % confidence interval. The accuracy of the measurement in terms of relative deviation from the IAEA recommended value was ±0.83 %. "In-house" prepared As(III) and As(V) standards were used to validate the HPLC-INAA method used for the As species determination. Total As concentration in the water samples ranged from 1.15 to 9.20 mg/L. As(III) species in water varied from 0.13 to 0.7 mg/L, while As(V) species varied from 0.79 to 3.85 mg/L. Total As content in sediment ranged from 2,134 to 3,596 mg/kg dry mass. The levels of As(III) and As(V) species in the sediment ranges from 138 to 506 mg/kg dry mass and 156 to 385 mg/kg dry mass, respectively.

The distribution and accumulation of chromium in the water, sediment and macrophytes of Skadar lake

Directory of Open Access Journals (Sweden)

Kastratović Vlatko

2016-01-01

Full Text Available The aquatic macrophytes Phragmites australis (Cav. Trin. ex Steud., Ceratophyllum demersum L., and Lemna minor L. were used as bioindicator plant species in order to define contamination level by Cr in Skadar lake (Montenegro. Plants, water and sediments were tested for the content of Cr at six locations around Lake Skadar during four periods in 2011. The content of Cr in the examined sediment was in the range of 35.6-127 mg/kg dry weight. The largest proportion of detected Cr (50.6% was associated with the oxidizable phase in the form of organic complexes. The concentration of Cr in the studied macrophytes declined in the following order: C. demersum > P. australis > L. minor. The highest average content of Cr was detected in the leaf of C. demersum (11.4 mg/kg in April.

Trace metals in water and sediments from Ologe Lagoon, southwestern Nigeria

International Nuclear Information System (INIS)

Yusuf, K.A.; Osibanjo, O.

2006-01-01

The concentrations of trace metals in water and sediment samples from Ologe lagoon located in southwestern Nigeria were investigated. The lagoon is a source of water for domestic, transportation and fishing activities. The water quality characteristics for a period of two years (January, 1997 - November, 1998), and the speciation of metals in the lagoon sediments were evaluated. The lagoon water quality characteristics, with respect to heavy metal contamination, were compared with global averages for freshwater and international water quality standards for drinking water. All elements except iron, were well within the safety limits. Sequential extraction techniques were used to establish the association of the total concentrations of Zn, Cu, Pb, Cd and Mn in the sediment samples with their contents as exchangeable, carbonates, Fe/Mn oxides, and organic and residual fractions. The concentrations of trace metals in the whole sediments were generally below the world-wide background levels. When compared to a number of sediment quality guidelines, the concentrations of trace metals were found to be below the level considered to have the potential to cause biological effects. Pb and Cd were extracted from the residual fraction at values greater than 50%. The metals that were most easily extractable in the samples analyzed were Mn and Zn, which posed the highest risk to water contamination. The low level of industrialization in the study area has kept the lagoon relatively free from heavy metal contamination. (author)

Water-quality conditions and suspended-sediment transport in the Wilson and Trask Rivers, northwestern Oregon, water years 2012–14

Science.gov (United States)

Sobieszczyk, Steven; Bragg, Heather M.; Uhrich, Mark A.

2015-07-28

In October 2011, the U.S. Geological Survey began investigating and monitoring water-quality conditions and suspended-sediment transport in the Wilson and Trask Rivers, northwestern Oregon. Water temperature, specific conductance, turbidity, and dissolved oxygen were measured every 15–30 minutes in both streams using real-time instream water-quality monitors. In conjunction with the monitoring effort, suspended-sediment samples were collected and analyzed to model the amount of suspended sediment being transported by each river. Over the course of the 3-year study, which ended in September 2014, nearly 600,000 tons (t) of suspended-sediment material entered Tillamook Bay from these two tributaries. 

A hydrologic regression sediment-yield model for two ungaged watershed outlet stations in Africa

International Nuclear Information System (INIS)

Moussa, O.M.; Smith, S.E.; Shrestha, R.L.

1991-01-01

A hydrologic regression sediment-yield model was established to determine the relationship between water discharge and suspended sediment discharge at the Blue Nile and the Atbara River outlet stations during the flood season. The model consisted of two main submodels: (1) a suspended sediment discharge model, which was used to determine suspended sediment discharge for each basin outlet; and (2) a sediment rating model, which related water discharge and suspended sediment discharge for each outlet station. Due to the absence of suspended sediment concentration measurements at or near the outlet stations, a minimum norm solution, which is based on the minimization of the unknowns rather than the residuals, was used to determine the suspended sediment discharges at the stations. In addition, the sediment rating submodel was regressed by using an observation equations procedure. Verification analyses on the model were carried out and the mean percentage errors were found to be +12.59 and -12.39, respectively, for the Blue Nile and Atbara. The hydrologic regression model was found to be most sensitive to the relative weight matrix, moderately sensitive to the mean water discharge ratio, and slightly sensitive to the concentration variation along the River Nile's course

Antibiotics in surface water and sediments from Hanjiang River, Central China: Occurrence, behavior and risk assessment.

Science.gov (United States)

Hu, Ying; Yan, Xue; Shen, Yun; Di, Mingxiao; Wang, Jun

2018-08-15

Thirteen antibiotics including sulfonamides (SAs), tetracyclines (TETs) and fluoroquinolones (FQs) were measured in Hanjiang River (HR) during two periods. The total concentrations of 13 antibiotics in surface water and sediments ranged from 3.1 to 109 ng/l and from 10 to 45 ng/g dry weight, respectively. SAs were dominant in water while the concentrations of TETs were the highest in sediments in two seasons. For their spatial distribution, total concentrations of 13 antibiotics in both matrices were significantly higher in the lower section of HR (p  5.15) due to wastewater release, agricultural activities and water transfer project. Obvious seasonal variations of sulfadiazine, sulfameter, trimethoprim and oxytetracycline in water were observed (p  4.62). Phase partition of antibiotics between water and sediments suggested a greater affinity of TETs and FQs to sediments. In addition, significantly positive relationships were found between SAs (sulfameter, sulfamethoxazole and trimethoprim) and sediment TOC (p Risk assessment indicated that the hazard quotients of antibiotics were higher in the sediment than those in the water. Moreover, antibiotic mixtures posed higher ecological risks to aquatic organisms. Copyright © 2018 Elsevier Inc. All rights reserved.

Surface water, particulate matter, and sediments of inland waters

International Nuclear Information System (INIS)

Mundschenk, H.

1985-01-01

The Bundesanstalt fuer Gewaesserkunde (BfG) since 1958 runs a system for monitoring the surface water and sediments of Federal German waterways in its capacity as a directing water monitoring centre. The data recorded over the years show that the radioactivity released by the various emission sources leads to radionuclide concentrations in water, particulate matter, or sediments that generally are below the detection limits defined in the relevant legal provisions governing monitoring and surveillance of nuclear facilities effluents. Representative examples of measuring methods and results (as for e.g. for H-3) are given. (DG) [de

A sediment resuspension and water quality model of Lake Okeechobee

Science.gov (United States)

James, R.T.; Martin, J.; Wool, T.; Wang, P.-F.

1997-01-01

The influence of sediment resuspension on the water quality of shallow lakes is well documented. However, a search of the literature reveals no deterministic mass-balance eutrophication models that explicitly include resuspension. We modified the Lake Okeeehobee water quality model - which uses the Water Analysis Simulation Package (WASP) to simulate algal dynamics and phosphorus, nitrogen, and oxygen cycles - to include inorganic suspended solids and algorithms that: (1) define changes in depth with changes in volume; (2) compute sediment resuspension based on bottom shear stress; (3) compute partition coefficients for ammonia and ortho-phosphorus to solids; and (4) relate light attenuation to solids concentrations. The model calibration and validation were successful with the exception of dissolved inorganic nitrogen species which did not correspond well to observed data in the validation phase. This could be attributed to an inaccurate formulation of algal nitrogen preference and/or the absence of nitrogen fixation in the model. The model correctly predicted that the lake is lightlimited from resuspended solids, and algae are primarily nitrogen limited. The model simulation suggested that biological fluxes greatly exceed external loads of dissolved nutrients; and sedimentwater interactions of organic nitrogen and phosphorus far exceed external loads. A sensitivity analysis demonstrated that parameters affecting resuspension, settling, sediment nutrient and solids concentrations, mineralization, algal productivity, and algal stoichiometry are factors requiring further study to improve our understanding of the Lake Okeechobee ecosystem.

Chronic toxicity of nickel-spiked freshwater sediments: variation in toxicity among eight invertebrate taxa and eight sediments

Science.gov (United States)

Besser, John M.; Brumbaugh, William G.; Ingersoll, Christopher G.; Ivey, Chris D.; Kunz, James L.; Kemble, Nile E.; Schlekat, Christian E.; Garman, Emily R.

2013-01-01

This study evaluated the chronic toxicity of Ni-spiked freshwater sediments to benthic invertebrates. A 2-step spiking procedure (spiking and sediment dilution) and a 2-stage equilibration period (10 wk anaerobic and 1 wk aerobic) were used to spike 8 freshwater sediments with wide ranges of acid-volatile sulfide (AVS; 0.94–38 µmol/g) and total organic carbon (TOC; 0.42–10%). Chronic sediment toxicity tests were conducted with 8 invertebrates (Hyalella azteca, Gammarus pseudolimnaeus, Chironomus riparius, Chironomus dilutus, Hexagenia sp., Lumbriculus variegatus, Tubifex tubifex, and Lampsilis siliquoidea) in 2 spiked sediments. Nickel toxicity thresholds estimated from species-sensitivity distributions were 97 µg/g and 752 µg/g (total recoverable Ni; dry wt basis) for sediments with low and high concentrations of AVS and TOC, respectively. Sensitive species were tested with 6 additional sediments. The 20% effect concentrations (EC20s) for Hyalella and Gammarus, but not Hexagenia, were consistent with US Environmental Protection Agency benchmarks based on Ni in porewater and in simultaneously extracted metals (SEM) normalized to AVS and TOC. For Hexagenia, sediment EC20s increased at less than an equimolar basis with increased AVS, and toxicity occurred in several sediments with Ni concentrations in SEM less than AVS. The authors hypothesize that circulation of oxygenated water by Hexagenia led to oxidation of AVS in burrows, creating microenvironments with high Ni exposure. Despite these unexpected results, a strong relationship between Hexagenia EC20s and AVS could provide a basis for conservative site-specific sediment quality guidelines for Ni.

Cesium, manganese and cobalt water-sediment transfer kinetics and diffusion into mangrove sediments inferred by radiotracer experiments

International Nuclear Information System (INIS)

Machado, E.C.; Machado, W.; Patchineelam, S.R.

2012-01-01

A study on the trace elements transfer from tidal water to mangrove sediments from Guanabara Bay (southeastern Brazil) was performed in laboratory microcosms. Sediment cores were covered with tidal water spiked with 137 Cs, 54 Mn and 57 Co during 5-h experiments, and water samples were taken at regular intervals to measure uptake kinetics at the sediment-water interface. At the end of the experiments, the uptake and diffusional penetration into the sediments was evaluated. Half-removal times from water to sediments were slightly higher for 137 Cs (3.4 ± 1.7 h) than observed for 54 Mn (2.3 ± 0.2 h) and 57 Co (2.6 ± 1.1 h). After these experiments, all radioisotopes presented decreasing activities with increasing sediment depth, being the distribution of 137 Cs indicative of higher diffusion within the upper 2 cm. This study on the removal of 137 Cs, 54 Mn and 57 Co from tidal water by mangrove sediments suggests that while 57 Co and 54 Mn presented closer behaviors, there was a slightly higher mobility of 137 Cs. (author)

Microplastic particles in sediments from Danish waters

DEFF Research Database (Denmark)

Strand, Jakob; Lassen, Pia; Shashoua, Yvonne

. In some samples, several hundred particles consisting of fibres, flakes, spherules, and/or granules were identified per 100 g sediment, and also in sediments from open waters. Relationships to sediment characteristics (e.g. dry weight, TOC, grain size) and inorganic and organic contaminants including...

Occurrence and origin of Escherichia coli in water and sediments at two public swimming beaches at Lake of the Ozarks State Park, Camden County, Missouri, 2011-13

Science.gov (United States)

Wilson, Jordan L.; Schumacher, John G.; Burken, Joel G.

2014-01-01

In the past several years, the Missouri Department of Natural Resources has closed two popular public beaches, Grand Glaize Beach and Public Beach 1, at Lake of the Ozarks State Park in Osage Beach, Missouri when monitoring results exceeded the established Escherichia coli (E. coli) standard. As a result of the beach closures, the U.S. Geological Survey and Missouri University of Science and Technology, in cooperation with the Missouri Department of Natural Resources, led an investigation into the occurrence and origins of E. coli at Grand Glaize Beach and Public Beach 1. The study included the collection of more than 1,300 water, sediment, and fecal source samples between August 2011 and February 2013 from the two beaches and vicinity. Spatial and temporal patterns of E. coli concentrations in water and sediments combined with measurements of environmental variables, beach-use patterns, and Missouri Department of Natural Resources water-tracing results were used to identify possible sources of E. coli contamination at the two beaches and to corroborate microbial source tracking (MST) sampling efforts. Results from a 2011 reconnaissance sampling indicate that water samples from Grand Glaize Beach cove contained significantly larger E. coli concentrations than adjacent coves and were largest at sites at the upper end of Grand Glaize Beach cove, indicating a probable local source of E. coli contamination within the upper end of the cove. Results from an intensive sampling effort during 2012 indicated that E. coli concentrations in water samples at Grand Glaize Beach cove were significantly larger in ankle-deep water than waist-deep water, trended downward during the recreational season, significantly increased with an increase in the total number of bathers at the beach, and were largest during the middle of the day. Concentrations of E. coli in nearshore sediment (sediment near the shoreline) at Grand Glaize Beach were significantly larger in foreshore samples

Developing and testing an Early Warning System for Non Indigenous Species and Ballast Water Management

Science.gov (United States)

Magaletti, Erika; Garaventa, Francesca; David, Matej; Castriota, Luca; Kraus, Romina; Luna, Gian Marco; Silvestri, Cecilia; Forte, Cosmo; Bastianini, Mauro; Falautano, Manuela; Maggio, Teresa; Rak, Giulietta; Gollasch, Stephan

2018-03-01

This paper describes the methodological approach used for the development of an Early Warning System (EWS) for Non Indigenous Species (NIS) and ballast water management and summarizes the results obtained. The specific goals of the EWS are firstly to warn vessels to prevent loading of ballast water when critical biological conditions occur in ports and surrounding areas i.e. mass development or blooms of Harmful Aquatic Organisms and Pathogens (HAOP). Secondly, to warn environmental and health authorities when NIS or pathogens are present in ports or surrounding areas to enable an early response and an implementation of remediation measures. The EWS is designed to be used for implementing various parallel obligations, by taking into consideration different legal scopes, associated information and decision-making needs. The EWS was elaborated, tested in the Adriatic Sea and illustrated by two case studies. Although the EWS was developed with an Adriatic Sea focus, it is presented in a format so that it may be used as a model when establishing similar systems in other locations. The role of the various actors is discussed and recommendations on further developments of the EWS are presented. It was concluded that the EWS is a suitable tool to reduce the spread of potentially harmful and ballast water mediated species.

Managing erosion, sediment transport and water quality in drained peatland catchments

Energy Technology Data Exchange (ETDEWEB)

Marttila, H.

2010-07-01

effect of the PRC is on SS and SS-bound nutrients. The sixth paper is concentrated to test new restoration structure to be used in degraded headwater brooks. The results show that addition of woody restoration structures to the channel is effective and simple sediment management methods in headwater areas. New information provided in this thesis on sediment erosion and transport processes in drained peatland areas can help to improve water quality control in these areas. In-channel processes are important for both peatland uses, since the drainage network often constitutes temporary interstorm storage for eroding and transporting material. Therefore, controlling these processes is a key to effective water quality management, which can be achieved using the PRC method in drainage areas or by utilisation of natural fluvial processes in natural channels downstream. (orig.)

Suspended sediment, turbidity, and stream water temperature in the Sauk River Basin, western Washington, water years 2012-16

Science.gov (United States)

Jaeger, Kristin L.; Curran, Christopher A.; Anderson, Scott W.; Morris, Scott T.; Moran, Patrick W.; Reams, Katherine A.

2017-11-01

The Sauk River is a federally designated Wild and Scenic River that drains a relatively undisturbed landscape along the western slope of the North Cascade Mountain Range, Washington, which includes the glaciated volcano, Glacier Peak. Naturally high sediment loads characteristic of basins draining volcanoes like Glacier Peak make the Sauk River a dominant contributor of sediment to the downstream main stem river, the Skagit River. Additionally, the Sauk River serves as important spawning and rearing habitat for several salmonid species in the greater Skagit River system. Because of the importance of sediment to morphology, flow-conveyance, and ecosystem condition, there is interest in understanding the magnitude and timing of suspended sediment and turbidity from the Sauk River system and its principal tributaries, the White Chuck and Suiattle Rivers, to the Skagit River.Suspended-sediment measurements, turbidity data, and water temperature data were collected at two U.S. Geological Survey streamgages in the upper and middle reaches of the Sauk River over a 4-year period extending from October 2011 to September 2015, and at a downstream location in the lower river for a 5-year period extending from October 2011 to September 2016. Over the collective 5-year study period, mean annual suspended-sediment loads at the three streamgages on the upper, middle, and lower Sauk River streamgages were 94,200 metric tons (t), 203,000 t, and 940,000 t streamgages, respectively. Fine (smaller than 0.0625 millimeter) total suspended-sediment load averaged 49 percent at the upper Sauk River streamgage, 42 percent at the middle Sauk River streamgage, and 34 percent at the lower Sauk River streamgage.

Using aquatic macroinvertebrate species traits to build test batteries for sediment toxicity assessment: accounting for the diversity of potential biological responses to toxicants.

Science.gov (United States)

Ducrot, Virginie; Usseglio-Polatera, Philippe; Péry, T Alexandre R R; Mouthon, Jacques; Lafont, Michel; Roger, Marie-Claude; Garric, Jeanne; Férard, Jean-François

2005-09-01

An original species-selection method for the building of test batteries is presented. This method is based on the statistical analysis of the biological and ecological trait patterns of species. It has been applied to build a macroinvertebrate test battery for the assessment of sediment toxicity, which efficiently describes the diversity of benthic macroinvertebrate biological responses to toxicants in a large European lowland river. First, 109 potential representatives of benthic communities of European lowland rivers were selected from a list of 479 taxa, considering 11 biological traits accounting for the main routes of exposure to a sediment-bound toxicant and eight ecological traits providing an adequate description of habitat characteristics used by the taxa. Second, their biological and ecological trait patterns were compared using coinertia analysis. This comparison allowed the clustering of taxa into groups of organisms that exhibited similar life-history characteristics, physiological and behavioral features, and similar habitat use. Groups exhibited various sizes (7-35 taxa), taxonomic compositions, and biological and ecological features. Main differences among group characteristics concerned morphology, substrate preferendum and habitat utilization, nutritional features, maximal size, and life-history strategy. Third, the best representatives of the mean biological and ecological characteristics of each group were included in the test battery. The final selection was composed of Chironomus riparius (Insecta: Diptera), Branchiura sowerbyi (Oligochaeta: Tubificidae), Lumbriculus variegatus (Oligochaeta: Lumbriculidae), Valvata piscinalis (Gastropoda: Valvatidae), and Sericostoma personatum (Trichoptera: Sericostomatidae). This approach permitted the biological and ecological variety of the battery to be maximized. Because biological and ecological traits of taxa determine species sensitivity, such maximization should permit the battery to better account

Contaminant characterization of sediment and pore-water in the Clinch River and Poplar Creek

International Nuclear Information System (INIS)

Levine, D.A.; Harris, R.A.; Campbell, K.R.; Hargrove, W.W.; Rash, C.D.

1995-01-01

Sediment and pore-water samples were collected from 80 locations in the Clinch River and Poplar Creek system to characterize concentrations and spatial distribution of contaminants for use in ecological risk assessment. Sediment cores were collected at each site and the top 15 cm was analyzed to represent the biologically active zone. Sediment for pore-water extraction was collected in large volumes using a Ponar grab sampler. Pore-water was extracted from this sediment using centrifugation, All samples were analyzed for metals (including methyl mercury), organics, and radiological constituents. Additionally, sediment was analyzed for physical properties: particle size distribution, density, and porosity. Sediment and pore-water were also analyzed for total organic carbon and nitrogen and ammonia levels. Sediment and pore-water were also analyzed for total organic carbon and nitrogen and ammonia levels. Sediment and pre-water results indicate that there are several areas where concentrations of a variety of contaminants are high enough to causes ecological effects. These locations in the river are immediately downstream from know sources of Contamination from on-site DOE facilities. East Fork Poplar Creek is a source of several metals, including mercury, cadmium, chromium, and copper. Mitchell Branch is a source of number of metals, uranium isotopes, technetium-99, and several PAHs. There are two clear sources of arsenic and selenium to the system, one in Poplar Creek and one in Melton Hill Reservoir, both related to past disposal of coal-ash. High concentrations in sediments did not always coincide with high concentrations in pore-water for the same sites and contaminants. This appears to be related to particle size of the sediment and total organic carbon

Arsenic and antimony geochemistry of mine wastes, associated waters and sediments at the Giant Mine, Yellowknife, Northwest Territories, Canada

International Nuclear Information System (INIS)

Fawcett, Skya E.; Jamieson, Heather E.; Nordstrom, D. Kirk; McCleskey, R. Blaine

2015-01-01

Highlights: • Antimony and arsenic were speciated in sediments and pore waters near Giant Mine. • Sediments will continue to be a source of arsenic and antimony to overlying water. • Aquatic vegetation traps contaminated sediment and takes up antimony and arsenic. - Abstract: Elevated levels of arsenic (As) and antimony (Sb) in water and sediments are legacy residues found downstream from gold-mining activities at the Giant Mine in Yellowknife, Northwest Territories (NWT), Canada. To track the transport and fate of As and Sb, samples of mine-waste from the mill, and surface water, sediment, pore-water, and vegetation downstream of the mine were collected. Mine waste, pore-water, and sediment samples were analyzed for bulk chemistry, and aqueous and solid-state speciation. Sediment and vegetation chemistry were evaluated using scanning electron microscope imaging, synchrotron-based element mapping and electron microprobe analysis. The distributions of As and Sb in sediments were similar, yet their distributions in the corresponding pore-waters were mostly dissimilar, and the mobility of As was greater than that of Sb. Competition for sorption sites is the most likely cause of elevated Sb concentrations in relatively oxidized pore-water and surface water. The aqueous and solid-state speciation of As and Sb also differed. In pore-water, As(V) dominated in oxidizing environments and As(III) in reducing environments. In contrast, the Sb(V) species dominated in all but one pore-water sample, even under reducing conditions. Antimony(III) appears to preferentially precipitate or adsorb onto sulfides as evidenced by the prevalence of an Sb(III)-S secondary solid-phase and the lack of Sb(III)(aq) in the deeper zones. The As(V)–O solid phase became depleted with depth below the sediment–water interface, and the Sb(V)–O phase persisted under relatively reducing conditions. In the surficial zone at a site populated by Equisetum fluviatile (common horsetail), As and

Lead (Pb Accumulation in Water, Sediment and Mussels (Hiatula chinensis from Pasir Panjang Coast, Lekok-Pasuruan

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Defri Yona

2016-10-01

Full Text Available This study attempted to evaluate Pb accumulation in the water, sediment and mussels (Hiatula chinensis from Lekok-Pasuruan. There were four sampling stations representing the study area: (1 urban areas, (2 water flow area from steam power plant (PLTU, (3 waste disposal area of PLTU, (4 fishing port. The average concentration of lead varied between stations in the water (0.279 ppm, sediment (0.423 ppm and mussels (0.427 ppm. Pearson`s correlation test shows strong relationship (p > 0.05 between Pb in the water, sediment and Hiatula chinensis. Mussels accumulation of lead from the sediment was assessed using bio-concentration factor (BCF and the result shows Hiatula chinensis is an accumulator of Pb (BCF > 1.

Bioturbation and dissolved organic matter enhance contaminant fluxes from sediment treated with powdered and granular activated carbon.

Science.gov (United States)

Kupryianchyk, D; Noori, A; Rakowska, M I; Grotenhuis, J T C; Koelmans, A A

2013-05-21

Sediment amendment with activated carbon (AC) is a promising technique for in situ sediment remediation. To date it is not clear whether this technique sufficiently reduces sediment-to-water fluxes of sediment-bound hydrophobic organic chemicals (HOCs) in the presence of bioturbators. Here, we report polychlorobiphenyl (PCB) pore water concentrations, fluxes, mass transfer coefficients, and survival data of two benthic species, for four treatments: no AC addition (control), powdered AC addition, granular AC addition and addition and subsequent removal of GAC (sediment stripping). AC addition decreased mass fluxes but increased apparent mass transfer coefficients because of dissolved organic carbon (DOC) facilitated transport across the benthic boundary layer (BBL). In turn, DOC concentrations depended on bioturbator activity which was high for the PAC tolerant species Asellus aquaticus and low for AC sensitive species Lumbriculus variegatus. A dual BBL resistance model combining AC effects on gradients, DOC facilitated transport and biodiffusion was evaluated against the data and showed how the type of resistance differs with treatment and chemical hydrophobicity. Data and simulations illustrate the complex interplay between AC and contaminant toxicity to benthic organisms and how differences in species tolerance affect mass fluxes from sediment to the water column.

Water induced sediment levitation enhances downslope transport on Mars.

Science.gov (United States)

Raack, Jan; Conway, Susan J; Herny, Clémence; Balme, Matthew R; Carpy, Sabrina; Patel, Manish R

2017-10-27

On Mars, locally warm surface temperatures (~293 K) occur, leading to the possibility of (transient) liquid water on the surface. However, water exposed to the martian atmosphere will boil, and the sediment transport capacity of such unstable water is not well understood. Here, we present laboratory studies of a newly recognized transport mechanism: "levitation" of saturated sediment bodies on a cushion of vapor released by boiling. Sediment transport where this mechanism is active is about nine times greater than without this effect, reducing the amount of water required to transport comparable sediment volumes by nearly an order of magnitude. Our calculations show that the effect of levitation could persist up to ~48 times longer under reduced martian gravity. Sediment levitation must therefore be considered when evaluating the formation of recent and present-day martian mass wasting features, as much less water may be required to form such features than previously thought.

Heavy metals and hydrocarbon concentrations in water, sediments and tissue of Cyclope neritea from two sites in Suez Canal, Egypt and histopathological effects.

Science.gov (United States)

Sharaf, Hesham M; Shehata, Abdalla M

2015-01-01

Heavy metals and hydrocarbons are of the most common marine pollutants around the world. The present study aimed to assess the concentration of petroleum hydrocarbons and heavy metals in tissues of the snail cyclope neritea, water and sediments from two sites of the study area (Temsah lake and Suez canal) represent polluted and unpolluted sites respectively. The results showed that, the levels of the heavy metals (Pb, Cd, Co, Mg and Zn) in the polluted area have reached harmful limits recorded globally. Lead in water, sediment and tissue of the snail reached to 0.95 ppm, 4.54 ppm and 7.93 ppm respectively. Cadmium reached 0.31 ppm, 1.15 ppm and 3.08 ppm in the corresponding samples. Cobalt was not detected in water, but it reached 1.42 ppm and 10.36 ppm in the sediment and snails tissue respectively. Magnesium in water, sediment and tissue of the snail reached 3.73 ppm, 9.44 ppm and12.6 ppm respectively. Zinc reached 0.11 ppm, 3.89 ppm and 12.60ppm in the corresponding samples. Meanwhile, hydrocarbons in the polluted area (site1) reached 110.10 μg/L, 980.15 μg/g and 228.00 μg/g in water sediment and digestive gland tissues of the snails respectively. Whereas, hydrocarbons in the unpolluted area (site2) were estimated as 14.20 μg/L, 55.60 μg/g and 22.66 μg/g in water, sediment and tissue of the snails respectively. The combination of histopathological image with monitoring of the metal level in the digestive gland of the present snail provides an important tool for early detection of impending environmental problems and potential public health issues. Petroleum hydrocarbons are toxic to the marine fauna when present above certain limit in the marine water. The major detoxification organ in molluscs is the digestive gland, which has been used as a bioindicator organ for toxicity assessment. The effect of high crude oil on the digestive gland tubules of exposed snails when examined microscopically reveals a series of histological changes which indicates that the

Sediment transport in two mediterranean regulated rivers.

Science.gov (United States)

Lobera, G; Batalla, R J; Vericat, D; López-Tarazón, J A; Tena, A

2016-01-01

Mediterranean climate is characterized by highly irregular rainfall patterns with marked differences between wet and dry seasons which lead to highly variable hydrological fluvial regimes. As a result, and in order to ensure water availability and reduce its temporal variability, a high number of large dams were built during the 20th century (more than 3500 located in Mediterranean rivers). Dams modify the flow regime but also interrupt the continuity of sediment transfer along the river network, thereby changing its functioning as an ecosystem. Within this context, the present paper aims to assess the suspended sediment loads and dynamics of two climatically contrasting Mediterranean regulated rivers (i.e. the Ésera and Siurana) during a 2-yr period. Key findings indicate that floods were responsible for 92% of the total suspended sediment load in the River Siurana, while this percentage falls to 70% for the Ésera, indicating the importance of baseflows on sediment transport in this river. This fact is related to the high sediment availability, with the Ésera acting as a non-supply-limited catchment due to the high productivity of the sources (i.e. badlands). In contrast, the Siurana can be considered a supply-limited system due to its low geomorphic activity and reduced sediment availability, with suspended sediment concentration remaining low even for high magnitude flood events. Reservoirs in both rivers reduce sediment load up to 90%, although total runoff is only reduced in the case of the River Ésera. A remarkable fact is the change of the hydrological character of the River Ésera downstream for the dam, shifting from a humid mountainous river regime to a quasi-invariable pattern, whereas the Siurana experiences the opposite effect, changing from a flashy Mediterranean river to a more constant flow regime below the dam. Copyright © 2015 Elsevier B.V. All rights reserved.

Capabilities of Seven Species of Aquatic Macrophytes for Phytoremediation of Pentachlorophenol Contaminated Sediment

Science.gov (United States)

Zhao, Liangyuan; Guo, Weijie; Li, Qingyun; Li, Huan; Zhao, Weihua; Cao, Xiaohuan

2017-01-01

Sediments are regarded as the ultimate sink of pentachlorophenol(PCP) in aquatic environment, and capabilities of seven species of aquatic macrophytes for remediating PCP contaminated sediment were investigated. Seven species of aquatic macrophytes could significantly accelerate the degradation of PCP in sediments. Among all, canna indica L., Acorus calamus L. and Iris tectorum Maxim. can be used as efficient alternative plants for remediation of PCP contaminated sediment, which attained 98%, 92% and 88% of PCP removal in sediments, respectively. PCP was detected only in root tissues and the uptake was closely related to the root lipid contents of seven plants. The presence of seven aquatic macrophytes significantly increased microbial populations and the activities of dehydrogenase compared with control sediments, indicating that rhizosphere microorganism played important role in the remediation process. In conclusion, seven species of aquatic macrophytes may act as promising tools for the PCP phytoremediation in aquatic environment, especially Canna indica L., Acorus calamus L. and Iris tectorum Maxim.

The impact of pre-restoration land-use and disturbance on sediment structure, hydrology and the sediment geochemical environment in restored saltmarshes.

Science.gov (United States)

Spencer, Kate L; Carr, Simon J; Diggens, Lucy M; Tempest, James A; Morris, Michelle A; Harvey, Gemma L

2017-06-01

Saltmarshes are being lost or degraded as a result of human activity resulting in loss of critical ecosystem services including the provision of wild species diversity, water quality regulation and flood regulation. To compensate, saltmarshes are being restored or re-created, usually driven by legislative requirements for increased habitat diversity, flood regulation and sustainable coastal defense. Yet, there is increasing evidence that restoration may not deliver anticipated ecosystem services; this is frequently attributed to poor drainage and sediment anoxia. However, physical sediment characteristics, hydrology and the sediment geochemical environment are rarely examined in restoration schemes, despite such factors being critical for plant succession. This study presents the novel integration of 3D-computed X-ray microtomography to quantify sediment structure and porosity, with water level and geochemical data to understand the impact of pre-restoration land use and disturbance on the structure and functioning of restored saltmarshes. The study combines a broad-scale investigation of physical sediment characteristics in nine de-embanked saltmarshes across SE England, with an intensive study at one site examining water levels, sediment structure and the sediment geochemical environment. De-embankment does not restore the hydrological regime, or the physical/chemical framework in the saltmarshes and evidence of disturbance includes a reduction in microporosity, pore connectivity and water storage capacity, a lack of connectivity between the sub-surface environment and overlying floodwaters, and impeded sub-surface water flow and drainage. This has significant consequences for the sediment geochemical environment. This disturbance is evident for at least two decades following restoration and is likely to be irreversible. It has important implications for plant establishment in particular, ecosystem services including flood regulation, nutrient cycling and wild

MONITORING OF PHOSPHORUS CONTENT IN “WATER-PARTICULATE MATERIALS-BOTTOM SEDIMENTS SYSTEM” FOR RIVER PRUT

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VASILE RUSU

2011-03-01

Full Text Available Monitoring of phosphorus content in “water-particulatematerials-bottom sediments system” for river Prut. Seasonal and spatialdynamics of phosphorus forms in water, particulate materials and bottomsediments of river Prut was elucidated. The scheme for determination ofphosphorus forms in water and particulate materials according to World HealthOrganization classification was evaluated. Additionally, this scheme was tested forestimation of phosphorus content in bottom sediments. The supplemented schemeallows the analysis of the phosphorus forms for the entirely system “water –particulate materials – bottom sediments”, extending possibilities for interpretationof phosphorus dynamics in natural waters.

Sediment, water pollution indicators for heavy metals

International Nuclear Information System (INIS)

Cabaleiro, S.; Horn, A.

2010-01-01

The complexity of an aquatic system requires consideration of its dynamics: spatial and temporal variations of physical, chemical and biological. Heavy metals have peculiar behavior in the aquatic system and may not be available in the waters, but on sediments.The sub-basin of the Sarandi stream is responsible for the contamination of Pampulha Lake. The Instituto Mineiro das Águas – IGAM - uses tool for monitoring the quality of surface water for developing strategies for conservation, restoration and rational use of water resources. So through the indices: IQA ( Indice de qualidade de águas) Index of water quality, and TC- toxic contamination, reduces conflicts, implements the disciplining of the environmental economy.This study determined the monitoring of sediment and water of Sarandi Stream, so in the samples collected during dry and rainy seasons (2007- 2008) were analyzed heavy metals (Cu, Cd, Cr, Co, Ni, Zn, Pb) and physical-chemical factors (conductivity, solids dissolved, temperature, turbidity). This allowed the determination of Hackanson factors of contamination and Muller Index geoaccumulation, indicating very high contamination in sediments regarding the elements Cr, Cu, and Cd, and high contamination for Pb, Zn, and Mn. The comparison with the indices of water quality- IQA (IGAM - 2006, 2007 and 2008), combined with exploratory data analysis and graphs of correlation between the variables indicated favorable conditions for metals contamination on water and sediment for these metals, besides allowing the identification of its source

Spectroscopic characterization of uranium in evaporation basin sediments

Science.gov (United States)

Duff, M. C.; Morris, D. E.; Hunter, D. B.; Bertsch, P. M.

2000-05-01

Evaporation ponds in the San Joaquin Valley (SJV), CA, used for the containment of irrigation drainage waters contain elevated levels of uranium (U) resulting from the extensive leaching by carbonate-rich irrigation waters of the local agricultural soils that contain low levels of naturally-occurring U. The SJV ponds are subjected to changes in redox chemistry with cycles of drying and flooding. Our past studies have shown that U in the SJV Pond 14 surface sediments is present as mostly the oxidized and soluble form, U(VI). However, we were uncertain whether the U in the soil was only present as a U oxide of mixed stoichiometry, such as U 3O 8(s) (pitchblende) or other species. Here we present characterization information, which includes wet chemical and in situ spectroscopic techniques (X-ray absorption near-edge structure (XANES) and low temperature time-resolved luminescence spectroscopies) for samples from two SJV Pond sediments. Surface sediments from SJV Pond 16 were characterized for average oxidation state of U with XANES spectroscopy. The fraction of U(VI) to U(IV) in the Pond 16 sediments decreased with depth with U(IV) being the dominant oxidation state in the 5 cm to 15 cm depth. Two luminescent U(VI) species were identified in the surface sediments from Pond 14; a U(VI)-tricarbonate phase and another phase likely comprised of U(VI)-hydroxide or hydroxycarbonate. The luminescent U(VI) population in the Pond 16 sediments is dominated by species with comparable spectral characteristics to the U(VI)-hydroxide or hydroxycarbonate species found in the Pond 14 sediments. The luminescence spectroscopic results were complemented by wet chemical U leaching methods, which involved the use of carbonate and sulfuric acid solutions and oxidizing solutions of peroxide, hypochlorite and Mn(IV). Leaching was shown to decrease the total U concentration in the sediments in all cases. However, results from luminescence studies of the residual fraction in the leached

Reconstructing bottom water temperatures from measurements of temperature and thermal diffusivity in marine sediments

Science.gov (United States)

Miesner, F.; Lechleiter, A.; Müller, C.

2015-07-01

Continuous monitoring of oceanic bottom water temperatures is a complicated task, even in relatively easy-to-access basins like the North or Baltic seas. Here, a method to determine annual bottom water temperature variations from inverse modeling of instantaneous measurements of temperatures and sediment thermal properties is presented. This concept is similar to climate reconstructions over several thousand years from deep borehole data. However, in contrast, the presented method aims at reconstructing the recent temperature history of the last year from sediment thermal properties and temperatures from only a few meters depth. For solving the heat equation, a commonly used forward model is introduced and analyzed: knowing the bottom water temperature variations for the preceding years and the thermal properties of the sediments, the forward model determines the sediment temperature field. The bottom water temperature variation is modeled as an annual cosine defined by the mean temperature, the amplitude and a phase shift. As the forward model operator is non-linear but low-dimensional, common inversion schemes such as the Newton algorithm can be utilized. The algorithms are tested for artificial data with different noise levels and for two measured data sets: from the North Sea and from the Davis Strait. Both algorithms used show stable and satisfying results with reconstruction errors in the same magnitude as the initial data error. In particular, the artificial data sets are reproduced with accuracy within the bounds of the artificial noise level. Furthermore, the results for the measured North Sea data show small variances and resemble the bottom water temperature variations recorded from a nearby monitoring site with relative errors smaller than 1 % in all parameters.

RFID tags as a direct tracer for water and sediment dynamics

Science.gov (United States)

Sommerer, Erik; Plate, Simon; Güntner, Andreas

2014-05-01

RFID (Radio Frequency IDentification) is a wireless automatic identification system to track objects with widespread application in industrial operations, but also selected applications in ecological research (animal tracking) and for hydro-sedimentological studies (sediment transport with RFID tags embedded in bedload material). In this study, for the first time, we test and apply RFID tags as a direct tracer to track water pathways, erosion patterns and sediment transport on the surface at the hillslope and headwater scale. The RFID system used here consists of tags with a size of 12 x 2 mm and a combination of mobile and stationary antennas. The transport pathways and velocities of the RFID tags can be individually assessed due to their unique identification numbers. The study area is a badland of easily erodible marls and carbonates located in the Villacarli catchment (42 km²) in the Central Spanish Pyrenees. The badlands have been identified as one of the main sediment sources for siltation of the downstream Barasona Reservoir. More than 700 tags were placed in different terrain units using three experimental setups, including lab experiments: (i) intensive feasibility tests ranging from laboratory flume experiments to tracer studies under natural channel and slope conditions to compare the transport of RFID tags relative to colored particles of the natural sediment; (ii) several transects across the badland to investigate sediment transfer characteristics on different morphological units (i.e. channel, rills, slopes); (iii) a raster of 99 RFID tags covering a slope flank with vegetated and unvegetated parts to reveal the influence of vegetation to erosion and transport processes. The detection of transported tags was carried out with a mobile antenna system to map the spatial distribution of tags after selected rainfall events and with two stationary antennas in channel cross-sections for time-continuous observation of tag passage. From the observations, we

Spatial variation in sediment-water exchange of phosphorus in Florida Bay: AMP as a model organic compound.

Science.gov (United States)

Huang, Xiao-Lan; Zhang, Jia-Zhong

2010-10-15

Dissolved organic phosphorus (DOP) has been recognized as dominant components in total dissolved phosphorus (TDP) pools in many coastal waters, and its exchange between sediment and water is an important process in biogeochemical cycle of phosphorus. Adenosine monophosphate (AMP) was employed as a model DOP compound to simulate phosphorus exchange across sediment-water interface in Florida Bay. The sorption data from 40 stations were fitted to a modified Freundlich equation and provided a detailed spatial distribution both of the sediment's zero equilibrium phosphorus concentration (EPC(0-T)) and of the distribution coefficient (K(d-T)) with respect to TDP. The K(d-T) was found to be a function of the index of phosphorus saturation (IPS), a molar ratio of the surface reactive phosphorus to the surface reactive iron oxide content in the sediment, across the entire bay. However, the EPC(0-T) was found to correlate to the contents of phosphorus in the eastern bay only. Sediment in the western bay might act as a source of the phosphorus in the exchange process due to their high EPC(0-T) and low K(d-T), whereas sediments in the eastern bay might act as a sink because of their low EPC(0-T) and high K(d-T). These results strongly support the hypothesis that both phosphorus and iron species in calcareous marine sediments play a critical role in governing the sediment-water exchange of both phosphate and DOP in the coastal and estuarine ecosystems.

Modelling of flow and settling in storm water sedimentation tanks

OpenAIRE

Kluck, J.

1994-01-01

In the near future in the Netherlands many reservoirs will have to be built to abate the pollution of the surface water by overflowing storm water from combined sewer systems [Kluck, 1992-a]. These reservoirs, called storm water sedimentation tanks, reduce the pollution in two ways. The most important is by simply storing a part of the sewage (waste water and storm water) and thus reducing the quantity of overflowing water. The second is by providing flow conditions in which particles can set...

Two hake species, deep-water Cape hake Merluccius paradoxus ...

African Journals Online (AJOL)

denise

paradoxus and shallow-water Cape hake M. capensis, are found along the ... For both species, average length increased with depth. M. paradoxus expanded its ..... Evolution of the Benguela, physical features and processes. In Oceano-.

Performance of a hydrostatic sampler for collecting samples at the water-sediment interface in lakes

Directory of Open Access Journals (Sweden)

Fernando PEDROZO

2008-02-01

Full Text Available The water-sediment interface plays a significant role in the determination of the trophic degree of a waterbody. Numerous redox reactions take place there, resulting in the release of contaminants from the sediments to the water column. The aim of the present work was to develop an equipment for collecting samples from the water-sediment interface. Such equipment was to have a simple design, low construction cost, no depth limitations, and high levels of personal safety and to be reliable in the collection of samples. The performance of the hydrostatic sampler thus developed was tested against samples collected either remotely with a corer or directly with syringes by autonomous divers. The hydrostatic sampler permits access to depths where the costs of the traditional diving methodology are expensive, and where working conditions are dangerous for the diver. The hydrostatic sampler provides an additional means of collecting samples from the water-sediment interface, which together with pore-water samples, facilitates the investigation and understanding of chemical mechanisms in lakes, for instance, those that control the P release from sediment to the water column.

Physicochemical Factors Influence the Abundance and Culturability of Human Enteric Pathogens and Fecal Indicator Organisms in Estuarine Water and Sediment

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Francis Hassard

2017-10-01

Full Text Available To assess fecal pollution in coastal waters, current monitoring is reliant on culture-based enumeration of bacterial indicators, which does not account for the presence of viable but non-culturable or sediment-associated micro-organisms, preventing effective quantitative microbial risk assessment (QMRA. Seasonal variability in viable but non-culturable or sediment-associated bacteria challenge the use of fecal indicator organisms (FIOs for water monitoring. We evaluated seasonal changes in FIOs and human enteric pathogen abundance in water and sediments from the Ribble and Conwy estuaries in the UK. Sediments possessed greater bacterial abundance than the overlying water column, however, key pathogenic species (Shigella spp., Campylobacter jejuni, Salmonella spp., hepatitis A virus, hepatitis E virus and norovirus GI and GII were not detected in sediments. Salmonella was detected in low levels in the Conwy water in spring/summer and norovirus GII was detected in the Ribble water in winter. The abundance of E. coli and Enterococcus spp. quantified by culture-based methods, rarely matched the abundance of these species when measured by qPCR. The discrepancy between these methods was greatest in winter at both estuaries, due to low CFU's, coupled with higher gene copies (GC. Temperature accounted for 60% the variability in bacterial abundance in water in autumn, whilst in winter salinity explained 15% of the variance. Relationships between bacterial indicators/pathogens and physicochemical variables were inconsistent in sediments, no single indicator adequately described occurrence of all bacterial indicators/pathogens. However, important variables included grain size, porosity, clay content and concentrations of Zn, K, and Al. Sediments with greater organic matter content and lower porosity harbored a greater proportion of non-culturable bacteria (including dead cells and extracellular DNA in winter. Here, we show the link between physicochemical

Occurrence and partitioning of antibiotic compounds found in the water column and bottom sediments from a stream receiving two wastewater treatment plant effluents in Northern New Jersey, 2008

Energy Technology Data Exchange (ETDEWEB)

Gibs, Jacob, E-mail: jgibs@usgs.gov [U.S. Geological Survey, 810 Bear Tavern Road, West Trenton, NJ 08628 (United States); Heckathorn, Heather A. [U.S. Geological Survey, 810 Bear Tavern Road, West Trenton, NJ 08628 (United States); Meyer, Michael T. [U.S. Geological Survey, 4821 Quail Crest Place, Lawrence, KS 66049 (United States); Klapinski, Frank R.; Alebus, Marzooq; Lippincott, Robert L. [New Jersey Department of Environmental Protection, PO Box 413, Trenton, NJ 08625 (United States)

2013-08-01

An urban watershed in northern New Jersey was studied to determine the presence of four classes of antibiotic compounds (macrolides, fluoroquinolones, sulfonamides, and tetracyclines) and six degradates in the water column and bottom sediments upstream and downstream from the discharges of two wastewater treatment plants (WWTPs) and a drinking-water intake (DWI). Many antibiotic compounds in the four classes not removed by conventional WWTPs enter receiving waters and partition to stream sediments. Samples were collected at nine sampling locations on 2 days in September 2008. Two of the nine sampling locations were background sites upstream from two WWTP discharges on Hohokus Brook. Another background site was located upstream from a DWI on the Saddle River above the confluence with Hohokus Brook. Because there is a weir downstream of the confluence of Hohokus Brook and Saddle River, the DWI receives water from Hohokus Brook at low stream flows. Eight antibiotic compounds (azithromycin (maximum concentration 0.24 μg/L), ciprofloxacin (0.08 μg/L), enrofloxacin (0.015 μg/L), erythromycin (0.024 μg/L), ofloxacin (0.92 μg/L), sulfamethazine (0.018 μg/L), sulfamethoxazole (0.25 μg/L), and trimethoprim (0.14 μg/L)) and a degradate (erythromycin–H{sub 2}O (0.84 μg/L)) were detected in the water samples from the sites downstream from the WWTP discharges. The concentrations of six of the eight detected compounds and the detected degradate compound decreased with increasing distance downstream from the WWTP discharges. Azithromycin, ciprofloxacin, ofloxacin, and trimethoprim were detected in stream-bottom sediments. The concentrations of three of the four compounds detected in sediments were highest at a sampling site located downstream from the WWTP discharges. Trimethoprim was detected in the sediments from a background site. Pseudo-partition coefficients normalized for streambed sediment organic carbon concentration were calculated for azithromycin

Occurrence and partitioning of antibiotic compounds found in the water column and bottom sediments from a stream receiving two wastewater treatment plant effluents in Northern New Jersey, 2008

International Nuclear Information System (INIS)

Gibs, Jacob; Heckathorn, Heather A.; Meyer, Michael T.; Klapinski, Frank R.; Alebus, Marzooq; Lippincott, Robert L.

2013-01-01

An urban watershed in northern New Jersey was studied to determine the presence of four classes of antibiotic compounds (macrolides, fluoroquinolones, sulfonamides, and tetracyclines) and six degradates in the water column and bottom sediments upstream and downstream from the discharges of two wastewater treatment plants (WWTPs) and a drinking-water intake (DWI). Many antibiotic compounds in the four classes not removed by conventional WWTPs enter receiving waters and partition to stream sediments. Samples were collected at nine sampling locations on 2 days in September 2008. Two of the nine sampling locations were background sites upstream from two WWTP discharges on Hohokus Brook. Another background site was located upstream from a DWI on the Saddle River above the confluence with Hohokus Brook. Because there is a weir downstream of the confluence of Hohokus Brook and Saddle River, the DWI receives water from Hohokus Brook at low stream flows. Eight antibiotic compounds (azithromycin (maximum concentration 0.24 μg/L), ciprofloxacin (0.08 μg/L), enrofloxacin (0.015 μg/L), erythromycin (0.024 μg/L), ofloxacin (0.92 μg/L), sulfamethazine (0.018 μg/L), sulfamethoxazole (0.25 μg/L), and trimethoprim (0.14 μg/L)) and a degradate (erythromycin–H 2 O (0.84 μg/L)) were detected in the water samples from the sites downstream from the WWTP discharges. The concentrations of six of the eight detected compounds and the detected degradate compound decreased with increasing distance downstream from the WWTP discharges. Azithromycin, ciprofloxacin, ofloxacin, and trimethoprim were detected in stream-bottom sediments. The concentrations of three of the four compounds detected in sediments were highest at a sampling site located downstream from the WWTP discharges. Trimethoprim was detected in the sediments from a background site. Pseudo-partition coefficients normalized for streambed sediment organic carbon concentration were calculated for azithromycin, ciprofloxacin

Sediment transport following water transfer from Yangtze River to Taihu Basin

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Zheng Gong

2011-12-01

Full Text Available To meet the increasing need of fresh water and to improve the water quality of Taihu Lake, water transfer from the Yangtze River was initiated in 2002. This study was performed to investigate the sediment distribution along the river course following water transfer. A rainfall-runoff model was first built to calculate the runoff of the Taihu Basin in 2003. Then, the flow patterns of river networks were simulated using a one-dimensional river network hydrodynamic model. Based on the boundary conditions of the flow in tributaries of the Wangyu River and the water level in Taihu Lake, a one-dimensional hydrodynamic and sediment transport numerical model of the Wangyu River was built to analyze the influences of the inflow rate of the water transfer and the suspended sediment concentration (SSC of inflow on the sediment transport. The results show that the water transfer inflow rate and SSC of inflow have significant effects on the sediment distribution. The higher the inflow rate or SSC of inflow is, the higher the SSC value is at certain cross-sections along the river course of water transfer. Higher inflow rate and SSC of inflow contribute to higher sediment deposition per kilometer and sediment thickness. It is also concluded that a sharp decrease of the inflow velocity at the entrance of the Wangyu River on the river course of water transfer induces intense sedimentation at the cross-section near the Changshu hydro-junction. With an increasing distance from the Changshu hydro-junction, the sediment deposition and sedimentation thickness decrease gradually along the river course.

Test results of six-month test of two water electrolysis systems

Science.gov (United States)

Mills, E. S.; Wells, G. W.

1972-01-01

The two water electrolysis systems used in the NASA space station simulation 90-day manned test of a regenerative life support system were refurbished as required and subjected to 26-weeks of testing. The two electrolysis units are both promising systems for oxygen and hydrogen generation and both needed extensive long-term testing to evaluate the performance of the respective cell design and provide guidance for further development. Testing was conducted to evaluate performance in terms of current, pressure, variable oxygen demands, and orbital simulation. An automatic monitoring system was used to record, monitor and printout performance data at one minute, ten minute or one-hour intervals. Performance data is presented for each day of system operation for each module used during the day. Failures are analyzed, remedial action taken to eliminate problems is discussed and recommendations for redesign for future space applications are stated.

DEVELOPMENT AND DEMONSTRATION OF A BIDIRECTIONAL ADVECTIVE FLUX METER FOR SEDIMENT-WATER INTERFACE

Science.gov (United States)

A bidirectional advective flux meter for measuring water transport across the sediment-water interface has been successfully developed and field tested. The flow sensor employs a heat-pulse technique combined with a flow collection funnel for the flow measurement. Because the dir...

Effect of lixiviated sediments affected with treated water on Selenastrum capricornutum, Printz and Origanum vulgare L.

Science.gov (United States)

Ramos, Guadalupe E; Lopez, Martin H; Flores, Antonio M; Figueroa, Guadalupe T; De Leon, Fernando G

2010-01-01

Xochimilco is an area of Mexico City fulfilling important ecological functions. However, the water of the canal network in the lacustrine zone of Xochimilco is supplied by the water treatment plants of the city, implying a risk of accumulated contaminants in the sediments. This study reports the effect of lixiviates obtained from sediments collected in the canals of Xochimilco on the growth of the alga Selenastrum capricornutum and the angiosperm Origanum vulgare. Three factors were tested: (a) water source in terms of the effluent from the two water treatment plants (urban waste-water, located at Cerro de la Estrella (CE) and urban-rural waters at San Luis Tlaxialtemalco (SLT); (b) sampling season (January, dry season; May and September, rainy season; and (c) distances from the water discharge point in the Xochimilco's main canal (5200 and 1000 m for CE, and 0, 200 m for SLT). The chemical water properties analyzed were: pH, electrical conductivity, N-NO(3), N-NH(3), N(Total), P-PO(4) and P(Total). The alga was more sensitive to the contaminants than O. vulgare, showing growth inhibition of 93-100%. The effect of sampling season on the inhibition of algal growth was ordered as follows: September > May > January. Lixiviates obtained from sediment samples 200 and 1000 m from the main point of water discharge caused a higher algal growth inhibition than the samples obtained at the source point. Lixiviate promoted the growth of seedlings of O. vulgare.

Modified finite element transport model, FETRA, for sediment and radionuclide migration in open coastal waters

International Nuclear Information System (INIS)

Onishi, Y.; Arnold, E.M.; Mayer, D.W.

1979-08-01

The finite element model, FETRA, simulates transport of sediment and radionuclides (and other contaminants, such as heavy metals, pesticides, and other toxic substances) in surface water bodies. The model is an unsteady, two-dimensional (longitudinal and lateral) model which consists of the following three submodels coupled to include sediment-contaminant interactions: (1) sediment transport submodel, (2) dissolved contaminant transport submodel, and (3) particulate contaminant (contaminant adsorbed by sediment) transport submodel. Under the current phase of the study, FETRA was modified to include sediment-wave interaction in order to extend the applicability of the model to coastal zones and large lakes (e.g., the Great Lakes) where wave actions can be one of the dominant mechanisms to transport sediment and toxic contaminant. FETRA was further modified to handle both linear and quadratic approximations to velocity and depth distributions in order to be compatible with various finite element hydrodynamic models (e.g., RMA II and CAFE) which supply hydrodynamic input data to FETRA. The next step is to apply FETRA to coastal zones to simulate transport of sediment and radionuclides with their interactions in order to test and verify the model under marine and large lacustrine environments

Effect of resuspension on the release of heavy metals and water chemistry in anoxic and oxic sediments

Energy Technology Data Exchange (ETDEWEB)

Hwang, Kyung-Yup; Kim, Hong-Seok; Hwang, Inseong [School of Civil and Environmental Engineering, Pusan National University, Busan (Korea, Republic of)

2011-10-15

Two types of river sediments with contrasting characteristics (anoxic or oxic) were resuspended and the release of heavy metals and changes in water chemistry were investigated. During resuspension of the anoxic sediment, the dissolved oxygen (DO) concentration and redox potential of the water layer decreased abruptly within the first 1 min, followed by increases toward the end of the resuspension period. Heavy metals were released rapidly in the first 6 h, probably due to the oxidation of acid volatile sulfide (AVS) of the anoxic sediment, and then the aqueous phase concentrations of the heavy metals decreased due to resorption onto the sediment until the 12-h point. During resuspension of the oxic sediment, the DO concentration and redox potential remained relatively constant in the oxic ranges. The heavy metals were released from the oxic sediment gradually during a 24-h resuspension period. The temporal maximum concentrations of Ni, Cu, Zn, and Cd in the aqueous phases in both experiments frequently exceeded the USEPA water quality criteria or the water quality guidelines of Australia and New Zealand. This suggests that a resuspension event could bring about temporal water quality deterioration in the two sediment environments. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

The effect of sediment mimicking drill cuttings on deep water rhodoliths in a flow-through system: Experimental work and modeling

International Nuclear Information System (INIS)

Figueiredo, Marcia A.O.; Eide, Ingvar; Reynier, Marcia; Villas-Bôas, Alexandre B.; Tâmega, Frederico T.S.

2015-01-01

Highlights: • Collection of rhodoliths and calcareous algae from Campos Basin, Brazil. • Impact of sediment mimicking drill cuttings on photosynthetic efficiency. • Exposure–response for photosynthetic efficiency as function of sediment coverage. • Factorial design and multivariate regression used for a structured approach. - Abstract: The impact of sediment coverage on two rhodolith-forming calcareous algae species collected at 100 m water depth off the coast of Brazil was studied in an experimental flow-through system. Natural sediment mimicking drill cuttings with respect to size distribution was used. Sediment coverage and photosynthetic efficiency (maximum quantum yield of charge separation in photosystem II, ϕ PSIImax ) were measured as functions of light intensity, flow rate and added amount of sediment once a week for nine weeks. Statistical experimental design and multivariate data analysis provided statistically significant regression models which subsequently were used to establish exposure–response relationship for photosynthetic efficiency as function of sediment coverage. For example, at 70% sediment coverage the photosynthetic efficiency was reduced 50% after 1–2 weeks of exposure, most likely due to reduced gas exchange. The exposure–response relationship can be used to establish threshold levels and impact categories for environmental monitoring

Mollusca from a species-rich deep-water Leptometra community in the Alboran Sea

Directory of Open Access Journals (Sweden)

Serge Gofas

2014-12-01

Full Text Available An exceptional species richness for Mollusca was found on Avempace bank (349-365 m, Djibouti group, Alboran Sea, where the most abundant species was the crinoid Leptometra phalangium. A sample of sediment sieved on a 0.5-mm mesh yielded 156 species of molluscs (83 live-taken, 1772 specimens with a high Shannon-Wiener diversity index (H’(log2=3.60. The dominant mollusc was Limopsis aurita and the six most common species accounted for 77% of the specimens. On the other hand, 42 species were represented by only one or two specimens. Two species are described as new, three more are first findings in the Mediterranean and two are first findings in Iberian waters. One-third of the species have not been reported from the neighbouring, well-explored Alboran Island platform. There is a considerable balance between the trophic groups, denoting a stable and structured community. Most of the species have an extensive Atlantic range, and most have a planktonic larval stage. Therefore, it can be hypothesized that the fauna benefits from a diverse influx of larvae carried in by the more superficial incoming Atlantic current. Because of its exceptional richness, this type of bathyal community with Leptometra and Limopsis should be considered a high priority for habitat conservation in the Mediterranean deep sea.

Arsenic species in ecosystems affected by arsenic-rich spring water near an abandoned mine in Korea

Energy Technology Data Exchange (ETDEWEB)

Kim, Y.T. [Department of Earth System Science, Yonsei University, 134 Shinchon-Dong, Sudaemoon-Gu, Seoul 120-749 (Korea, Republic of); Nano Environment Materials Research Team, Korea Basic Science Institute, Seoul 136-600 (Korea, Republic of); Yoon, H.O., E-mail: dunee@kbsi.re.k [Nano Environment Materials Research Team, Korea Basic Science Institute, Seoul 136-600 (Korea, Republic of); Yoon, C. [Nano Environment Materials Research Team, Korea Basic Science Institute, Seoul 136-600 (Korea, Republic of); Woo, N.C., E-mail: ncwoo@yonsei.ac.k [Department of Earth System Science, Yonsei University, 134 Shinchon-Dong, Sudaemoon-Gu, Seoul 120-749 (Korea, Republic of)

2009-12-15

The objectives of this study were to quantitatively estimate the distribution of arsenic with its speciation and to identify potential pathways for transformation of arsenic species from samples of water, sediments, and plants in the ecosystem affected by the Cheongog Spring, where As(V) concentration reached levels up to 0.270 mg L{sup -1}. After flowing about 100 m downstream, the arsenic level showed a marked reduction to 0.044 mg L{sup -1} (about 84% removal) without noticeable changes in major water chemistry. The field study and laboratory hydroponic experiments with the dominant emergent plants along the creek (water dropwort and thunbergian smartweed) indicated that arsenic distribution, reduction, and speciation appear to be controlled by, (i) sorption onto stream sediments in exchangeable fractions, (ii) bioaccumulation by and possible release from emergent plants, and (iii) transformation of As(V) to As(III) and organic species through biological activities. - Biogeochemical reactions with emergent plants and sediments control the fate of arsenic along creeks originating from a high-As Spring.

Burying behaviour of two sympatric crab species: Cancer magister and Cancer productus

Directory of Open Access Journals (Sweden)

Iain J. McGaw

2005-09-01

Full Text Available The mechanics and emergence patterns associated with burying behaviour were investigated in the Dungeness crab, Cancer magister, and the red rock crab, Cancer productus. Cancer magister used both the legs and chelae to excavate the sand, whereas Cancer productus used the legs to pull and push itself down into the sediment only using the chelae in a final push beneath the sediment. Several individuals of each species remained buried for over 50 h, which was accomplished by alterations in ventilatory physiology. More commonly, both species exhibited an endogenous rhythm of circadian periodicity, with peak periods of emergence from the sand occurring during nocturnal high tides. Although burial may act as a means of predator evasion and to ambush prey, it appears the primary reason may be to conserve energy. These two species of crabs often occur sympatrically; the difference in behaviours is closely related to previously reported differences in physiological mechanisms between the two species when buried.

Uranium isotopes in waters and bottom sediments of rivers and lakes in Poland

International Nuclear Information System (INIS)

Pietrzak-Flis, Z.; Kaminska, I.; Chrzanowski, E.

2004-01-01

Activity concentrations of 238 U, 234 U and 235 U were determined in waters and bottom sediments in two main rivers in Poland (the Vistula and Odra rivers) with their tributaries, in four coastal rivers and six lakes. Concentration of 238 U and 233 U were compared with the concentrations of 226 Ra determined in another study. As compared with concentrations in coastal rivers and in lakes, enhanced concentrations of the radionuclides were observed in water and bottom sediments in the upper and middle courses of Vistula river, whereas in the Odra river the enhanced concentrations were present only in the bottom sediments. The enhanced concentrations in the Vistula river result from the discharge of coal mine waters from the Upper Silesian Coal Basin, and they indicate that the discharge was continued. The enhanced concentration in Odra river observed only in bottom sediments indicate that the discharge occurred in the past. The 234 U/ 238 U ratio for the bottom sediments was close to unity, indicating that these isotopes were close to equilibrium, whereas for water the average ratio was form 1.2 for lakes to 1.5 for the Vistula river, demonstrating the lack of equilibrium. (author)

Evaluation of metals, metalloids, and ash mixture toxicity using sediment toxicity testing.

Science.gov (United States)

Stojak, Amber; Bonnevie, Nancy L; Jones, Daniel S

2015-01-01

In December 2008, a release of 4.1 million m(3) of coal ash from the Tennessee Valley Authority Kingston Fossil Plant occurred. Ash washed into the Emory River and migrated downstream into the Clinch and Tennessee Rivers. A Baseline Ecological Risk Assessment evaluated risks to ecological receptors from ash in the river system post-dredging. This article describes the approach used and results from sediment toxicity tests, discussing any causal relationships between ash, metals, and toxicity. Literature is limited in the realm of aquatic coal combustion residue (CCR) exposures and the potential magnitude of effects on benthic invertebrates. Sediment samples along a spectrum of ash content were used in a tiered toxicity testing approach and included a combination of 10 day sediment toxicity acute tests and longer-term, partial life cycle "definitive" tests with 2 species (Hyalella azteca and Chironomus dilutus). Arsenic, and to a lesser extent Se, in the ash was the most likely toxicant causing observed effects in the laboratory toxicity tests. Sites in the Emory River with the greatest statistical and biologically significant effects had As concentrations in sediments twice the probable effects concentration of 33 mg/kg. These sites contained greater than 50% ash. Sites with less than approximately 50% ash in sediments exhibited fewer significant toxic responses relative to the reference sediment in the laboratory. The results discussed here present useful evidence of only limited effects occurring from a worst-case exposure pathway. These results provided a valuable line of evidence for the overall assessment of risks to benthic invertebrates and to other ecological receptors, and were crucial to risk management and development of project remediation goals. © 2014 SETAC.

Effects of Sediment Chemical Properties on Phosphorus Release Rates in the Sediment-Water Interface of the Steppe Wetlands.

Science.gov (United States)

He, Jing; Su, Derong; Lv, Shihai; Diao, Zhaoyan; Xie, Jingjie; Luo, Yan

2017-11-22

Rising temperature causes a process of phosphorus release, which can be characterized well using phosphorus release rates (V P ). The objective of the present study was to investigate the major factors affecting sediment phosphorus release rates through a wetland habitat simulation experiment. The results showed that the V P of different wetland sediments were different and changed with the order of W-R (river wetland) > W-L (lake wetland) > W-M (grassy marsh wetland) > W-A (reservoir wetland). The main driving factors which influenced sediment phosphorus flux velocity in the sediment-water interface were sediment B-SO₄ 2- , B-MBN and A-MBP content. Path analysis and determination coefficient analysis indicated the standard multiple regression equation for sediment phosphorus release rates in the sediment-water interface, and each main factor was Y = -0.105 + 0.096X₁ + 0.275X₂ - 0.010X₃ ( r = 0.416, p phosphorus release rates; X₁ is sediment B-SO₄ 2- content; X₂ is sediment B-MBN; and X₃ is sediment A-MBP content. Sediment B-SO₄ 2- , B-MBN and A-MBP content and the interaction between them were the main factors affecting sediment phosphorus release rates in the sediment-water interface. Therefore, these results suggest that soil chemical properties and microbial activities likely play an important role in phosphorus release rates in the sediment-water interface. We hope to provide effective scientific management and control methods for relevant environmental protection departments.

Suitability of seven species of soil-inhabiting invertebrates for testing toxicity of pesticides in soil pore water

NARCIS (Netherlands)

Ronday, R.; Houx, N.W.H.

1996-01-01

This study assessed the suitability of seven species of soil invertebrates for toxicologically testing pesticides in water. Requirements were that the organisms must survive in water, be easy to handle, be easy to breed, be sensitive to pesticides, and show unambiguous toxicological effects. The

Flow modelling to estimate suspended sediment travel times for two Canadian Deltas

Directory of Open Access Journals (Sweden)

S. R. Fassnacht

2000-01-01

Full Text Available The approximate travel times for suspended sediment transport through two multi-channel networks are estimated using flow modelling. The focus is on the movement of high sediment concentrations that travel rapidly downstream. Since suspended sediment transport through river confluences and bifurcation movement is poorly understood, it is assumed that the sediment moves at approximately the average channel velocity during periods of high sediment load movement. Calibration of the flow model is discussed, with an emphasis on the incorporation of cross-section data, that are not referenced to a datum, using a continuous water surface profile. Various flow regimes are examined for the Mackenzie and the Slave River Deltas in the Northwest Territories, Canada, and a significant variation in travel times is illustrated. One set of continuous daily sediment measurements throughout the Mackenzie Delta is used to demonstrate that the travel time estimates are reasonable. Keywords: suspended sediment; multi-channel river systems; flow modelling; sediment transport

Relationships between water transparency and abundance of Cynodontidae species in the Bananal floodplain, Mato Grosso, Brazil

Directory of Open Access Journals (Sweden)

Cesar Enrique de Melo

Full Text Available The Cerrado in the Central Brazil is currently one of the most threatened ecosystems in the world. As a result, the aquatic habitats in this biome also undergo great impacts. Alterations related to land-use change increase sediment loadings in rivers, streams and lakes, resulting in sedimentation and decrease in water transparency. Water transparency determines underwater visibility conditions, and as a consequence fish assemblages respond to spatial and temporal changes in this variable. This work aimed to examine the influence of transparency on the abundance and distribution of Cynodontidae species, a visually oriented predatory fish group. Fish sampling was conducted in 15 sites located between Mortes and Araguaia rivers in the Bananal floodplain, Mato Grosso State. Regression analysis between relative abundance of Cynodontidae (in number of individuals and biomass and water transparency showed a positive and highly significant correlation, indicating that this group shows species-specific habitat affinities for clearer waters. These results suggest that the increase in water turbidity in this region can affect the patterns of abundance and distribution of the Cynodontidae species, as well as other visually oriented fishes.

Top down arsenic uncertainty measurement in water and sediments from Guarapiranga dam (Brazil)

Science.gov (United States)

Faustino, M. G.; Lange, C. N.; Monteiro, L. R.; Furusawa, H. A.; Marques, J. R.; Stellato, T. B.; Soares, S. M. V.; da Silva, T. B. S. C.; da Silva, D. B.; Cotrim, M. E. B.; Pires, M. A. F.

2018-03-01

Total arsenic measurements assessment regarding legal threshold demands more than average and standard deviation approach. In this way, analytical measurement uncertainty evaluation was conducted in order to comply with legal requirements and to allow the balance of arsenic in both water and sediment compartments. A top-down approach for measurement uncertainties was applied to evaluate arsenic concentrations in water and sediments from Guarapiranga dam (São Paulo, Brazil). Laboratory quality control and arsenic interlaboratory tests data were used in this approach to estimate the uncertainties associated with the methodology.

Investigation of Composition of Particle Size in Sediments of Stormwater Sedimentation Tank

OpenAIRE

Daiva Laučytė; Regimantas Dauknys

2011-01-01

The main object for the storm water runoff treatment is to remove suspended solids before the storm water runoff is discharged into surface waters. Therefore the sedimentation tank is the most often used treatment facility. In order to optimise the sedimentation, the tendency of particle size distribution in bottom sediments must be known. Two similar size storm water runoff sedimentation tanks in Vilnius city were selected for the analysis of the particle size distribution in sediments. The ...

Development of a test system for the determination of biodegradability in surface waters

International Nuclear Information System (INIS)

Kalsch, W.; Knacker, T.; Robertz, M.; Schallnass, H.J.

1997-01-01

The study presented here describes the development of a laboratory test system for the determination of aerobic biodegradability of substances at low concentrations in surface water. It was aimed to prepare a draft guideline for a biodegradation simulation test according to OECD format. The experimental approach was based on a literature study conducted within the frame of this project. Further useful information on the possible test design was derived from the German BBA guideline 5-1. Natural water and sediments were collected. Radiolabelled Lindane or 4-Nitrophenol was added. The test vessels (reactors) were aerated and incubated under controlled conditions for up to 92 days. The results showed biological stability of the sediment/water systems even without addition of nutrients and adherence to non-reducing conditions. Mineralisation of 4-Nitrophenol was influenced by the sediment type, the method of aeration and temperature. Factors affecting the mineralisation of Lindane were the method of application and again, the sediment type and temperature. Considerable amounts of the radioactivity were bound to the sediment and were to a large extent unextractable. The potential of a reactor to mineralise a test substance could not be correlated with the biological parameters measured. (orig.) [de

Chemical quality of water and bottom sediment, Stillwater National Wildlife Refuge, Lahontan Valley, Nevada

Science.gov (United States)

Thodal, Carl E.

2017-12-28

The U.S. Geological Survey, in cooperation with the U.S. Fish and Wildlife Service collected data on water and bottom-sediment chemistry to be used to evaluate a new water rights acquisition program designed to enhance wetland habitat in Stillwater National Wildlife Refuge and in Lahontan Valley, Churchill County, Nevada. The area supports habitat critical to the feeding and resting of migratory birds travelling the Pacific Flyway. Information about how water rights acquisitions may affect the quality of water delivered to the wetlands is needed by stakeholders and Stillwater National Wildlife Refuge managers in order to evaluate the effectiveness of this approach to wetlands management. A network of six sites on waterways that deliver the majority of water to Refuge wetlands was established to monitor the quality of streamflow and bottom sediment. Each site was visited every 4 to 6 weeks and selected water-quality field parameters were measured when flowing water was present. Water samples were collected at varying frequencies and analyzed for major ions, silica, and organic carbon, and for selected species of nitrogen and phosphorus, trace elements, pharmaceuticals, and other trace organic compounds. Bottom-sediment samples were collected for analysis of selected trace elements.Dissolved-solids concentrations exceeded the recommended criterion for protection of aquatic life (500 milligrams per liter) in 33 of 62 filtered water samples. The maximum arsenic criterion (340 micrograms per liter) was exceeded twice and the continuous criterion was exceeded seven times. Criteria protecting aquatic life from continuous exposure to aluminum, cadmium, lead, and mercury (87, 0.72, 2.5, and 0.77 micrograms per liter, respectively) were exceeded only once in filtered samples (27, 40, 32, and 36 samples, respectively). Mercury was the only trace element analyzed in bottom-sediment samples to exceed the published probable effect concentration (1,060 micrograms per kilogram).

Antibiotic resistance and biofilm formation of some bacteria isolated from sediment, water and fish farms in Malaysia

Science.gov (United States)

Faja, Orooba Meteab; Usup, Gires; Ahmad, Asmat

2018-04-01

A total of 90 isolates of bacteria were isolated, from sediment (10) samples, water (10) samples and fish (12) samples (Sea bass, Snapper, Grouper and Tilapia). These include 22 isolates of bacteria from sediment, 28 isolates from water and 40 isolates from fish. All the isolates were tested for sensitivity to 13 antibiotics using disc diffusion method. The isolates showed high resistance to some antibiotics based on samples source. Isolates from sediment showed highest resistance toward novobiocin, kanamycin, ampicillin and streptomycin while isolates from water showed highest resistance against vancomycin, penicillin, streptomycin and tetracycline, in contrast, in fish sample showed highest resistance toward vancomycin, ampicillin, streptomycin and tetracycline. Most of the isolates showed biofilm formation ability with different degrees. Out of 22 bacteria isolates from water, two isolates were weak biofilm formers, six isolates moderate biofilm formers and fourteen isolates strong biofilm formers. While, out of 28 bacteria isolates from water one isolate was weak biofilm former, five isolates moderate biofilm formers and 22 strong biofilm formers Fish isolate showed three isolates (8%) moderate biofilm formers and 27 isolates strong biofilm formers. Biofilm formation was one of the factors that lead to antibiotic resistance of the bacterial isolates from these samples.

Herbicide monitoring in soil, runoff waters and sediments in an olive orchard.

Science.gov (United States)

Calderon, Maria Jesus; De Luna, Elena; Gomez, Jose Alfonso; Hermosin, M Carmen

2016-11-01

Occurrences of surface water contamination by herbicides in areas where olive orchards are established reveal a need to understand soil processes affecting herbicide fate at field scale for this popular Mediterranean crop. A monitoring study with two herbicides (terbuthylazine and oxyfluorfen) in the first 2cm of soil, runoff waters, and sediments, was carried out after under natural rainfall conditions following winter herbicide application. At the end of the 107day field experiment, no residues of the soil applied terbuthylazine were recovered, whereas 42% of the oxyfluorfen applied remained in the top soil. Very low levels of both herbicides were measured in runoff waters; however, concentrations were slightly higher for terbuthylazine (0.53% of applied) than for oxyfluorfen (0.03% of applied), relating to their respective water solubilities. Congruent with soil residue data, 38.15% of the applied oxyfluorfen was found in runoff-sediment, compared to only 0.46% for terbuthylazine. Accordingly, the herbicide soil distribution coefficients measured within runoff field tanks was much greater for oxyfluorfen (Kd=3098) than for terbuthylazine (Kd=1.57). The herbicide oxyfluorfen is co-transported with sediment in runoff, remaining trapped and/or adsorbed to soil particle aggregates, due in part to its low water solubility. In contrast, terbuthylazine soil dissipation may be associated more so with leaching processes, favored by its high water solubility, low sorption, and slow degradation. By comparing these two herbicides, our results reaffirm the importance of herbicide physico-chemical properties in dictating their behavior in soil and also suggest that herbicides with low solubility, as seen in the case oxyfluorfen, remain susceptible to offsite transport associated with sediments. Copyright © 2016 Elsevier B.V. All rights reserved.

Regulation of redox reactions of chemical species (arsenic and chromium) in sediment of Marque river. From experimentation to modeling

International Nuclear Information System (INIS)

Gorny, Josselin

2015-01-01

The French national radioactive waste management agency (Andra) and the Nord-Pas de Calais (NPDC) Region aim to better understand the fate of the redox sensitive trace elements in soils and river sediments to ameliorate the management of polluted sediments and of the storage of radioactive wastes. To address this problematic, some river sediments were selected as proxies, as strong redox gradients can be observed. Two methods have been developed to study the speciation of As and Cr: (i) HPIC-ICP-MS (High Performance Ionic Performance - Inductively Coupled Plasma - Mass Spectrometry) coupling in order to separate and quantify As [As(III), As(V), DMMA V and MMAA V ] and Cr species [Cr(III) and Cr(VI)], and (ii) DGT probes (Diffusive Gradient in Thin Film) containing specific chelating binding gels to quantify As species [As(III) and total As]. These methods have been implemented to monitor the low contaminated pore waters of the Marque river during 9 months. The results demonstrated that chromium is present only under its reduced form Cr(III), which makes difficult to assess the parameters that force redox interconversions between Cr(III) and Cr(VI). Arsenic is present only under its inorganic forms: As(III), As(V), and thio-arsenical species. Seasonal changes of As speciation in the dissolved phase depends mainly of S(-II) production by sulfate-reducing bacteria, which makes the amount of dissolved S(- II) an important parameter to follow through time since the As reduction increases its mobility and toxicity. (author) [fr

Contaminant profiles for surface water, sediment, flora and fauna associated with the mangrove fringe along middle and lower eastern Tampa Bay.

Science.gov (United States)

Lewis, M A; Russell, M J

2015-06-15

Contaminant concentrations are reported for surface water, sediment, flora and fauna collected during 2010-2011 from the mangrove fringe along eastern Tampa Bay, Florida. Concentrations of trace metals, chlorinated pesticides, atrazine, total polycyclic aromatic hydrocarbons, and polychlorinated biphenyls were species-, chemical- and location-specific. Contaminants in sediments did not exceed proposed individual sediment quality guidelines. Most sediment quality assessment quotients were less than one indicating the likelihood of no inhibitory effect based on chemical measurements alone. Faunal species typically contained more contaminants than plant species; seagrass usually contained more chemicals than mangroves. Bioconcentration factors for marine angiosperms were usually less than 10 and ranged between 1 and 31. Mercury concentrations (ppm) in blue crabs and fish did not exceed the U.S. Environmental Protection Agency fish tissue criterion of 0.3 and the U.S. Food and Drug Administration action level of 1.0. In contrast, total mercury concentrations in faunal species often exceeded guideline values for wildlife consumers of aquatic biota. Published by Elsevier Ltd.

Soil, Groundwater, Surface Water, and Sediments of Kennedy Space Center, Florida: Background Chemical and Physical Characteristics

Science.gov (United States)

Shmalzer, Paul A.; Hensley, Melissa A.; Mota, Mario; Hall, Carlton R.; Dunlevy, Colleen A.

2000-01-01

This study documented background chemical composition of soils, groundwater, surface; water, and sediments of Kennedy Space Center. Two hundred soil samples were collected, 20 each in 10 soil classes. Fifty-one groundwater wells were installed in 4 subaquifers of the Surficial Aquifer and sampled; there were 24 shallow, 16 intermediate, and 11 deep wells. Forty surface water and sediment samples were collected in major watershed basins. All samples were away from sites of known contamination. Samples were analyzed for organochlorine pesticides, aroclors, chlorinated herbicides, polycyclic aromatic hydrocarbons (PAH), total metals, and other parameters. All aroclors (6) were below detection in all media. Some organochlorine pesticides were detected at very low frequencies in soil, sediment, and surface water. Chlorinated herbicides were detected at very low frequencies in soil and sediments. PAH occurred in low frequencies in soiL, shallow groundwater, surface water, and sediments. Concentrations of some metals differed among soil classes, with subaquifers and depths, and among watershed basins for surface water but not sediments. Most of the variation in metal concentrations was natural, but agriculture had increased Cr, Cu, Mn, and Zn.

Toxicity assessment of sediments from three European river basins using a sediment contact test battery

NARCIS (Netherlands)

Tuikka, A.I.; Schmitt, C.; Hoess, S.; Bandow, N; von der Ohe, P.; de Zwart, D.; de Deckere, E.; Streck, G.; Mothes, S.; van Hattum, A.G.M.; Kocan, A.; Brix, R.; Brack, W.; Barcelo, D.; Sormunen, A.; Kukkonen, J.V.K.

2011-01-01

The toxicity of four polluted sediments and their corresponding reference sediments from three European river basins were investigated using a battery of six sediment contact tests representing three different trophic levels. The tests included were chronic tests with the oligochaete Lumbriculus

Rainfall-induced runoff from exposed streambed sediments: an important source of water pollution.

Science.gov (United States)

Frey, S K; Gottschall, N; Wilkes, G; Grégoire, D S; Topp, E; Pintar, K D M; Sunohara, M; Marti, R; Lapen, D R

2015-01-01

When surface water levels decline, exposed streambed sediments can be mobilized and washed into the water course when subjected to erosive rainfall. In this study, rainfall simulations were conducted over exposed sediments along stream banks at four distinct locations in an agriculturally dominated river basin with the objective of quantifying the potential for contaminant loading from these often overlooked runoff source areas. At each location, simulations were performed at three different sites. Nitrogen, phosphorus, sediment, fecal indicator bacteria, pathogenic bacteria, and microbial source tracking (MST) markers were examined in both prerainfall sediments and rainfall-induced runoff water. Runoff generation and sediment mobilization occurred quickly (10-150 s) after rainfall initiation. Temporal trends in runoff concentrations were highly variable within and between locations. Total runoff event loads were considered large for many pollutants considered. For instance, the maximum observed total phosphorus runoff load was on the order of 1.5 kg ha. Results also demonstrate that runoff from exposed sediments can be a source of pathogenic bacteria. spp. and spp. were present in runoff from one and three locations, respectively. Ruminant MST markers were also present in runoff from two locations, one of which hosted pasturing cattle with stream access. Overall, this study demonstrated that rainfall-induced runoff from exposed streambed sediments can be an important source of surface water pollution. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Temporal variations of water and sediment fluxes in the Cointzio river basin, central Mexico

Science.gov (United States)

Duvert, C.; Gratiot, N.; Navratil, O.; Esteves, M.; Prat, C.; Nord, G.

2009-04-01

The STREAMS program (Sediment TRansport and Erosion Across MountainS) was launched in 2006 to study suspended sediment dynamics in mountainous areas. Two watersheds were selected as part of the program: the Bléone river basin in the French Alps, and the Cointzio river basin (636 km2), located in the mountainous region of Michoacán, in central Mexico. The volcanic soils of the Cointzio catchment undergo important erosion processes, especially during flashflood events. Thus, a high-frequency monitoring of sediment transport is highly required. The poster presents the high-frequency database obtained from the 2008 hydrological season at the Santiago Undameo gauged station, located at the basin's outlet. Suspended Sediment Concentration (SSC) was estimated every 10 minutes by calibrating turbidity measurements with bottle sampling acquired on a double-daily basis. Water discharge time-series was approximated with continuous water-level measurements (5 minutes time-step), and a stage-discharge rating curve. Our investigation highlights the influence of sampling frequency on annual water and sediment fluxes estimate. A daily or even a weekly water-level measurement provides an unexpectedly reliable assessment of the seasonal water fluxes, with an under-estimation of about 5 % of the total flux. Concerning sediment fluxes, a high-frequency SSC survey appears to be necessary. Acquiring SSC data even twice a day leads to a significant (over 30 %) under-estimation of the seasonal sediment load. These distinct behaviors can be attributed to the fact that sediment transport almost exclusively occurs during brief night flood events, whereas exfiltration on the watershed always provides a base flow during the daily water-level measurements.

Contamination of water and sediments by obsolete pesticides at ...

African Journals Online (AJOL)

Sediments and water from Vikuge State Farm, Coast Region, Tanzania, where, in 1986, a “donation” of 170 m3 of partially expired pesticides were stored in an open shed- which eventually collapsed, were analysed for 80 different pesticide residues and metabolites. DDT and HCH, two of the most persistent ...

Combination of aquatic species and safeners improves the remediation of copper polluted water.

Science.gov (United States)

Panfili, Ivan; Bartucca, Maria Luce; Ballerini, Eleonora; Del Buono, Daniele

2017-12-01

In the last decades, many anthropogenic activities have resulted in heavy metal contamination of freshwaters and surrounding environments. This poses serious threats to human health. Phytoremediation is a cost-effective technology which is useful for remediating polluted soils and water. Recently, the use of aquatic free-floating plants has been proposed to remediate polluted water. In this context, a study on the capacity of two aquatic plants, Lemna minor (duckweed) and Salvinia auriculata (salvinia), to remediate Cu +2 (Cu) polluted water was carried out. Initially, the species were exposed to different copper concentrations (1, 5, 10, 20 and 50μmolL -1 ) in order to assess Cu +2 toxicity to the plants. In addition, plants were treated with two safeners (benoxacor and dichlormid), with the aim of pointing out any safening effect of these compounds on the aquatic species. Toxicity tests showed that safened plants had a greater Cu resistance, especially at the higher Cu doses. Finally, unsafened and safened plants were tested in the decontamination of water polluted by copper (1.2mgL -1 ). In general, duckweed removed higher amounts of Cu from polluted water than salvinia, and, surprisingly, for both the species the safeners significantly increased the plants' capacity to remove the metal from the polluted waters. Lastly, an HPLC-based method was developed and standardized to monitor the residual amounts of the two safeners in the water. While dichlormid was completely absorbed by duckweed within few days after the treatments, some residual amounts of both safeners were found in salvinia vegetated water after two weeks. In conclusion, the results of this research show that the use of aquatic species in combination with safeners is an attractive and reliable tool to make plants more effective in phytoremediation of water polluted with metals (or other toxic compounds). Copyright © 2017 Elsevier B.V. All rights reserved.

Heavy metals in water, sediments and submerged macrophytes in ponds around the Dianchi Lake, China.

Science.gov (United States)

Wang, Zhixiu; Yao, Lu; Liu, Guihua; Liu, Wenzhi

2014-09-01

Through retaining runoff and pollutants such as heavy metals from surrounding landscapes, ponds around a lake play an important role in mitigating the impacts of human activities on lake ecosystems. In order to determine the potential for heavy metal accumulation of submerged macrophytes, we investigated the concentrations of 10 heavy metals (i.e., As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in water, sediments, and submerged macrophytes collected from 37 ponds around the Dianchi Lake in China. Our results showed that both water and sediments of these ponds were polluted by Pb. Water and sediments heavy metal concentrations in ponds received urban and agricultural runoff were not significantly higher than those in ponds received forest runoff. This result indicates that a large portion of heavy metals in these ponds may originate from atmospheric deposition and weathering of background soils. Positive relationships were found among heavy metal concentrations in submerged macrophytes, probably due to the coaccumulation of heavy metals. For most heavy metals, no significant relationships were found between submerged macrophytes and their water and sediment environments. The maximum concentrations of Cr, Fe and Ni in Ceratophyllum demersum were 4242, 16,429 and 2662mgkg(-1), respectively. The result suggests that C. demersum is a good candidate species for removing heavy metals from polluted aquatic environments. Copyright © 2014 Elsevier Inc. All rights reserved.

Laboratory isotopic behaviour (2H, 18O) of sediments pore water during evaporation

International Nuclear Information System (INIS)

Ciolzyk, A.; Bariac, T.; Klamecki, A.; Jusserand, C.

1987-01-01

Two bare sediments (sand and loam) wetted with water of known isotopic composition have been subjected to evaporation in laboratory conditions. An attempt of application of classical isotopic evaporation models for free waters with reducing reservoir has been made, the better fit implies: a)laminar conditions of the atmosphere in the sediment under evaporation; b) a similar isotopic composition of water vapor as the isotopic composition of the water vapor of the external atmosphere. Variation of ε K and δ V H implies a better knowledge of the complex mechanisms of the atmosphere behaviour in the pore path of porous media under evaporation [fr

Water and Sediment Output Evaluation Using Cellular Automata on Alpine Catchment: Soana, Italy - Test Case

Science.gov (United States)

Pasculli, Antonio; Audisio, Chiara; Sciarra, Nicola

2017-12-01

In the alpine contest, the estimation of the rainfall (inflow) and the discharge (outflow) data are very important in order to, at least, analyse historical time series at catchment scale; determine the hydrological maximum and minimum estimate flood and drought frequency. Hydrological researches become a precious source of information for various human activities, in particular for land use management and planning. Many rainfall- runoff models have been proposed to reflect steady, gradually-varied flow condition inside a catchment. In these last years, the application of Reduced Complexity Models (RCM) has been representing an excellent alternative resource for evaluating the hydrological response of catchments, within a period of time up to decades. Hence, this paper is aimed at the discussion of the application of the research code CAESAR, based on cellular automaton (CA) approach, in order to evaluate the water and the sediment outputs from an alpine catchment (Soana, Italy), selected as test case. The comparison between the predicted numerical results, developed through parametric analysis, and the available measured data are discussed. Finally, the analysis of a numerical estimate of the sediment budget over ten years is presented. The necessity of a fast, but reliable numerical support when the measured data are not so easily accessible, as in Alpine catchments, is highlighted.

Dredged Material Evaluations: Review of Zooplankton Toxicity Test Methods for Marine Water Quality Evaluations

Science.gov (United States)

2016-09-01

term impacts of the DM while settling through the water column (elutriate toxicity tests), and long-term toxicity (whole sediment toxicity tests) and...elutriates are prepared according to guidance (USEPA/USACE 1991; 1998) by mixing sediment and site water and allowing settling for prescribed periods...of water and waste water . 17th ed. Washington, DC: APHA. Arnold, W. R., R. L. Diamond, and D. S. Smith. 2010a. The effects of salinity, pH, and

Phosphorus fractions and sorption dynamics in the sediments of two Ca-SO4 water reservoirs in the central Argentine Andes

Institute of Scientific and Technical Information of China (English)

José Gabriel León; Fernando Luis Pedrozo; Pedro Félix Temporetti

2017-01-01

Phosphorus (P) fractionation and sorption behavior were studied in the sediments of two calcium-sulfate (Ca-SO4:Ca2+170 mg L-1;SO42-400 mg L-1) water reservoirs in the southern central Argentine Andes-El Carrizal Reservoir (ECR),which stratifies in summer and El Nihuil Reservoir (ENR),which is vertically mixed throughout the year. Sediment size classes reflected the lithology of both basins and the reservoirs relative location:ECR (downstream from a valley adjacent to a mountain environment) had higher clay proportions while the sand fraction was more important in ENR (just next to a mountain environment). In both reservoirs, the chemical composition revealed low alteration and calcium enrichment. Total P content was relatively high (1.1–1.6 mg P kg-1 dry weight) as expected from the contribution of marine formations. P fractionation was dominated by Ca-P (ECR, 69%and ENR, 63%) followed by organic-P (23%) in summer-anoxic ECR and by iron/aluminum (Fe/Al)-P (27%) in oxic ENR. Batch experiments showed that sorption behavior in ECR had a typical Langmuir isotherm plot while in ENR that model fitted only at low dissolved P values (<5 mg P L-1) and co-precipitation evidence was observed at higher P con-centrations. It is proposed that lower Fe/Al-P content in anoxic (ECR) vs. oxic (ENR) sediments results from the P released from iron-bound phosphorus due to sulfate reduction-ferrous sulfide formation in an anoxic environment. This condition should enable ECR sediments to adsorb P into fresh oxidized iron, and ENR sediments to co-precipitate P with calcium due to Fe/Al-P saturation, as observed in batch experiments. This paper constitutes the first description of phosphorus content and dynamics in reser-voir sediments in arid central western Argentina, where water sulfate concentrations are naturally high due to basin lithology.

Effects of Hyporheic Water Fluxes and Sediment Grain Size on the Concentration and Diffusive Flux of Heavy Metals in the Streambed.

Science.gov (United States)

Liu, Qi; Song, Jinxi; Zhang, Guotao; Wang, Weize; Guo, Weiqiang; Tang, Bin; Kong, Feihe; Huo, Aidi

2017-09-06

The hyporheic zone regulates physicochemical processes in surface-groundwater systems and can be an important source of heavy metals in fluvial systems. This study assesses the pore water concentrations and diffusive fluxes of heavy metals with respect to the vertical water exchange flux (VWEF) and sediment grain size. Water and sediment samples were collected on August 2016 from upstream Site 1 and downstream Site 2 along the Juehe River in Shaanxi Province, China. Streambed vertical hydraulic conductivity (Kv) and the VWEF were estimated via the standpipe permeameter test method and Darcy's law. The heavy metal concentrations in the pore water were measured and the diffusive fluxes were calculated using Fick's first law. The VWEF patterns were dominated by upward flow, and Site 1 featured higher values of Kv and VWEF. Higher Cu and Zn concentrations occurred near the channel centre with coarse sand and gravel and greater upward VWEFs because coarser sediment and greater upward VWEFs cause stronger metal desorption capacity. Additionally, Cu and Zn at the two sites generally diffused from pore water to surface water, potentially due to the upward VWEF. The VWEF and sediment grain size are likely crucial factors influencing the heavy metal concentrations and diffusive fluxes.

Comparison of Toxicity of Sediments from Rivers with Different Levels of Anthropogenic Load (Middle Volga Region, Russia Based on Elutriate and Whole Sediment Tests

Directory of Open Access Journals (Sweden)

N.Yu. Stepanova

2016-09-01

Full Text Available Description of chemical characteristics and toxicity testing of whole sediment and elutri-ate have been performed with 35 samples taken during the monitoring of rivers in the Middle Volga region (Tatarstan, Russia in 2013. The locations analyzed are sites associated with agriculture, forestry, and petroleum hydrocarbons (oil production. The toxicity tests include: (1 Chlorella vulgaris (algal elutriate test, (2 Paramecium caudatum (ciliate elutriate test, (3 Daphnia magna (cladoceran whole sediment toxicity test, and (4 Heterocypris incongruens (ostracod whole sediment toxicity test. The concentrations of metals in 43% of sediment samples have been found to exceed probable effect concentration sediment quality guidelines (SQGs. However, the concentrations of polycyclic aromatic hydrocarbons (PAHs and organochlorine pesticides have turned out to be below SQGs in most sites. The correlation analysis has shown metal toxicity to daphnid reproduction and ostracod growth (R2 = 0.34–0.64 and ammonia (R2 = 0.49–0.54. A higher percentage of samples have shown toxicity in the whole sediment tests (86% compared to the elutriate tests (54%. A total of 91% of samples have demonstrated toxicity for at least one species. Toxicity has been most frequently observed for daphnid reproduction (83% of samples and ostracod growth (56% of samples compared to daphnid (23% survival, ostracod (11% survival, and ciliate reproduction (54% or algal growth (54%. The most polluted sediments have been registered in the area of oil production. The comparison of toxicity of the samples from different types of areas has indicated that 100% of samples from the oil production area, 94% of samples from the agricultural area, and 50% of samples from the forest area were toxic to at least one test organism.

A comparative study of stream water and stream sediment as geochemical exploration media in the Rio Tanama porphyry copper district, Puerto Rico

Science.gov (United States)

Learned, R.E.; Chao, T.T.; Sanzolone, R.F.

1985-01-01

To test the relative effectiveness of stream water and sediment as geochemical exploration media in the Rio Tanama porphyry copper district of Puerto Rico, we collected and subsequently analyzed samples of water and sediment from 29 sites in the rivers and tributaries of the district. Copper, Mo, Pb, Zn, SO42-, and pH were determined in the waters; Cu, Mo, Pb, and Zn were determined in the sediments. In addition, copper in five partial extractions from the sediments was determined. Geochemical contrast (anomaly-to-background quotient) was the principal criterion by which the effectiveness of the two media and the five extractions were judged. Among the distribution patterns of metals in stream water, that of copper most clearly delineates the known porphyry copper deposits and yields the longest discernable dispersion train. The distribution patterns of Mo, Pb, and Zn in water show little relationship to the known mineralization. The distribution of SO42- in water delineates the copper deposits and also the more extensive pyrite alteration in the district; its recognizable downstream dispersion train is substantially longer than those of the metals, either in water or sediment. Low pH values in small tributaries delineate areas of known sulfide mineralization. The distribution patterns of copper in sediments clearly delineate the known deposits, and the dispersion trains are longer than those of copper in water. The partial determinations of copper related to secondary iron and manganese oxides yield the strongest geochemical contrasts and longest recognizable dispersion trains. Significantly high concentrations of molybdenum in sediments were found at only three sites, all within one-half km downstream of the known copper deposits. The distribution patterns of lead and zinc in sediments are clearly related to the known primary lead-zinc haloes around the copper deposits. The recognizable downstream dispersion trains of lead and zinc are shorter than those of

Life-cycle testing of receiving waters with Ceriodaphnia dubia

Energy Technology Data Exchange (ETDEWEB)

Stewart, A.J.; Konetsky, B.K.

1996-12-31

Seven-day tests with Ceriodaphnia dubia are commonly used to estimate toxicity of effluents or receiving waters but can sometimes yield {open_quotes}no toxicity{close_quotes} outcomes even if pollutants are present. We conducted two sets of full life-cycle tests with C. dubia to (1) see if tests with longer exposure periods would reveal evidence for toxicity that might not be evident from 7-day tests, and (2) determine the relative importance of water quality versus food as factors influencing C. dubia reproduction. In the first set of tests, C. dubia was reared in diluted mineral water (negative control), water from a stream impacted by coal fly-ash, or water from a retention basin containing sediments contaminated with mercury, other metals and polychlorinated biphenyls. The second set of tests used water from the retention basin only, but this water was either filtered or not filtered, and food was either added or not added, prior to testing. C. dubia survival and reproduction did not differ much among the three water types in the first set of tests, but these two parameters were strongly affected by the filtering and food-addition treatments in the second set of tests. Thus, C. dubia appeared to be relatively insensitive to general water-quality factors, but quite sensitive to food-related factors. Regression analyses showed that the predictability of life-time reproduction by C. dubia from the results of 7-day tests was very low (R{sup 2}< 0.35) in five of the six experiments. The increase in predictability as a function of test duration also differed among water types in the first set of tests, and among treatments in the second set of tests. Thus, 7-day tests with C. dubia may be used to quantify water-quality problems, but it may not be possible to reliably extrapolate the results of these tests to longer time scales.

Bioavailability of sediment-associated and low-molecular-mass species of radionuclides/trace metals to the mussel Mytilus edulis

Energy Technology Data Exchange (ETDEWEB)

Borretzen, Peer [Department of Plant and Environmental Sciences, P.O. Box 50003, Norwegian University of Life Sciences, N-1432 As (Norway)], E-mail: peer.borretzen@gmail.com; Salbu, Brit [Department of Plant and Environmental Sciences, P.O. Box 50003, Norwegian University of Life Sciences, N-1432 As (Norway)

2009-04-15

Sediments can act as a sink for contaminants in effluents from industrial and nuclear installations or when released from dumped waste. However, contaminated sediments may also act as a potential source of radionuclides and trace metals to the water phase due to remobilisation of metals as dissolved species and resuspension of particles. The marine mussel Mytilus edulis is a filter-feeding organism that via the gills is subjected to contaminants in dissolved form and from contaminants associated to suspended particles via the digestive system. In this paper the bioavailability of sediment-associated and seawater diluted Cs, Co, Cd and Zn radioactive tracers to the filtering bivalve M. edulis has been examined. The mussels were exposed to tracers diluted in ultrafiltered (<10 kDa) seawater (Low Molecular Mass form) or to tracers associated with sediment particles from the Stepovogo Fjord at Novaya Zemlya in short-term uptake experiments, followed by 1-month depuration experiments in flow-through tanks. A toxicokinetic model was fitted to the uptake and depuration data, and the obtained parameters were used to simulate the significance of the two uptake pathways at different suspended sediment loads and sediment-seawater distribution coefficients. The results of the model simulations, assuming steady state conditions, suggest that resuspended particles from contaminated sediments can be a highly significant pathway for mussels in the order {sup 109}Cd {approx_equal} {sup 65}Zn < {sup 134}Cs < {sup 60}Co. The significance increases with higher suspended sediment load and with higher K{sub d}. Furthermore, the experimental depuration data suggest that Cs is retained longer and Co, Cd and Zn shorter by the mussels when associated with ingested sediments, than if the metals are taken up from the low molecular mass (LMM) phase.

Local scale marine modelling of Fukushima releases. Assessment of water and sediment contamination and sensitivity to water circulation description

International Nuclear Information System (INIS)

Periáñez, R.; Suh, Kyung-Suk; Min, Byung-Il

2012-01-01

Highlights: ► First simulations of Cs seabed sediment contamination after Fukushima releases. ► Effects of tides on dispersion patterns assessed: not significant. ► Two kinetic models for uptake/release reactions compared. ► Daily currents from two ocean models have been used. Results compared. ► Overall better results with JCOPE2 currents and 2-step kinetics. - Abstract: The dispersion of 137 Cs released from Fukushima nuclear power plant to the sea after the March 11th 2011 tsunami has been studied using numerical models. The 3D dispersion model consists of an advection/diffusion equation with terms describing uptake/release reactions between water and seabed sediments. The dispersion model has been fed with daily currents provided by HYCOM and JCOPE2 ocean models. Seabed sediment 137 Cs patterns obtained using both current data set have been compared. The impact of tides and of atmospheric deposition has been evaluated as well. It has been also found that a 2-step kinetic model (two consecutive reversible reactions) for describing water/sediment interactions produces better results than a 1-step model (one single reversible reaction).

Resuspension and settling of helminth eggs in water: Interactions with cohesive sediments.

Science.gov (United States)

Sengupta, Mita E; Andersen, Thorbjørn J; Dalsgaard, Anders; Olsen, Annette; Thamsborg, Stig M

2012-08-01

Helminth parasite eggs in low quality water represent main food safety and health hazards and are therefore important indicators used to determine whether such water can be used for irrigation. Through sedimentation helminth eggs accumulate in the sediment, however resuspension of deposited helminth eggs will lead to increased concentration of suspended eggs in the water. Our study aimed to determine the erodibility (erosion rate and erosion threshold) and settling velocity of Ascaris and Trichuris eggs as well as cohesive sediment at different time points after incorporation into the sediment. Cohesive sediment collected from a freshwater stream was used to prepare a sediment bed onto which helminth eggs were allowed to settle. The erodibility of both sediment and helminth eggs was found to decrease over time indicating that the eggs were incorporated into the surface material of the bed and that this material was stabilized through time. This interaction between eggs and bulk sediment was further manifested in an increased settling velocity of suspended eggs when sediment was present in the suspension as compared to a situation with settling in clean water. The incorporation into the sediment bed and the aggregation with sediment particles decrease the mobility of both helminth egg types. Our findings document that helminth eggs should not be viewed as single entities in water systems when modelling the distribution of eggs since both erodibility and settling velocity of eggs are determined by mobility of the sediment present in the water stream. Recalculation of the erosion threshold for helminth eggs and sediment showed that even at relatively low current velocities i.e. 0.07-0.12ms(-1) newly deposited eggs will be mobile in open irrigation channels. These environmental factors affecting resuspension must be taken into account when developing models for sedimentation of helminth eggs in different water systems. Copyright © 2012 Elsevier Ltd. All rights

An Eulerian two-phase flow model for sediment transport under realistic surface waves

Science.gov (United States)

Hsu, T. J.; Kim, Y.; Cheng, Z.; Chauchat, J.

2017-12-01

Wave-driven sediment transport is of major importance in driving beach morphology. However, the complex mechanisms associated with unsteadiness, free-surface effects, and wave-breaking turbulence have not been fully understood. Particularly, most existing models for sediment transport adopt bottom boundary layer approximation that mimics the flow condition in oscillating water tunnel (U-tube). However, it is well-known that there are key differences in sediment transport when comparing to large wave flume datasets, although the number of wave flume experiments are relatively limited regardless of its importance. Thus, a numerical model which can resolve the entire water column from the bottom boundary layer to the free surface can be a powerful tool. This study reports an on-going effort to better understand and quantify sediment transport under shoaling and breaking surface waves through the creation of open-source numerical models in the OpenFOAM framework. An Eulerian two-phase flow model, SedFoam (Cheng et al., 2017, Coastal Eng.) is fully coupled with a volume-of-fluid solver, interFoam/waves2Foam (Jacobsen et al., 2011, Int. J. Num. Fluid). The fully coupled model, named SedWaveFoam, regards the air and water phases as two immiscible fluids with the interfaces evolution resolved, and the sediment particles as dispersed phase. We carried out model-data comparisons with the large wave flume sheet flow data for nonbreaking waves reported by Dohmen-Janssen and Hanes (2002, J. Geophysical Res.) and good agreements were obtained for sediment concentration and net transport rate. By further simulating a case without free-surface (mimic U-tube condition), the effects of free-surface, most notably the boundary layer streaming effect on total transport, can be quantified.

Comparative study of plutonium and americium bioaccumulation from two marine sediments contaminated in the natural environment

International Nuclear Information System (INIS)

Hamilton, T.F.; Smith, J.D.

1991-01-01

Plutonium and americium sediment-animal transfer was studied under controlled laboratory conditions by exposure of the benthic polychaete Nereis diversicolor (O. F. Mueller) to marine sediments contaminated by a nuclear bomb accident (near Thule, Greenland) and nuclear weapons testing (Enewetak Atoll). In both sediment regimes, the bioavailability of plutonium and 241 Am was low, with specific activity in the tissues 241 Am occurred and 241 Am uptake from the Thule sediment was enhanced compared to that from lagoon sediments of Enewetak Atoll. Autoradiography studies indicated the presence of hot particles of plutonium in the sediments. The results highlight the importance of purging animals of their gut contents in order to obtain accurate estimates of transuranic transfer from ingested sediments into tissue. It is further suggested that enhanced transuranic uptake by some benthic species could arise from ingestion of highly activity particles and organic-rich detritus present in the sediments. (author)

Comparison of different water pollution control methods in decreaseing sediment load from peat mining areas

Energy Technology Data Exchange (ETDEWEB)

Kloeve, B.

1997-11-01

Different water treatment alternatives used to reduce sediment from peat mines were compared with a mathematical model. The simulation tested the benefit of different alternatives to reduce sediment transport during a simulated storm. Traditional structures such as bed ditch pipe barriers, sedimentation ponds were compared against new alternatives such as artificial floodplains, and peak runoff control structures. The results of simulations show that detention of peak discharge is the most efficient way to reduce sediment transport. When runoff peaks are reduced traditional sedimentation ponds seem to have a smaller effect on sediment transport; increased settling is achieved by using shallow settling basins such as artificial floodplains. (orig.) 21 refs.

Comparison of different water pollution control methods in decreaseing sediment load from peat mining areas

International Nuclear Information System (INIS)

Kloeve, B.

1997-01-01

Different water treatment alternatives used to reduce sediment from peat mines were compared with a mathematical model. The simulation tested the benefit of different alternatives to reduce sediment transport during a simulated storm. Traditional structures such as bed ditch pipe barriers, sedimentation ponds were compared against new alternatives such as artificial floodplains, and peak runoff control structures. The results of simulations show that detention of peak discharge is the most efficient way to reduce sediment transport. When runoff peaks are reduced traditional sedimentation ponds seem to have a smaller effect on sediment transport; increased settling is achieved by using shallow settling basins such as artificial floodplains. (orig.) 21 refs

Rhodotorula portillonensis sp. nov., a basidiomycetous yeast isolated from Antarctic shallow-water marine sediment.

Science.gov (United States)

Laich, Federico; Vaca, Inmaculada; Chávez, Renato

2013-10-01

During the characterization of the mycobiota associated with shallow-water marine environments from Antarctic sea, a novel pink yeast species was isolated. Sequence analysis of the D1/D2 domain of the LSU rDNA gene and 5.8S-ITS regions revealed that the isolated yeast was closely related to Rhodotorula pallida CBS 320(T) and Rhodotorula benthica CBS 9124(T). On the basis of morphological, biochemical and physiological characterization and phylogenetic analyses, a novel basidiomycetous yeast species, Rhodotorula portillonensis sp. nov., is proposed. The type strain is Pi2(T) ( = CBS 12733(T)  = CECT 13081(T)) which was isolated from shallow-water marine sediment in Fildes Bay, King George Island, Antarctica.

Biogeochemical malfunctioning in sediments beneath a deep-water fish farm.

Science.gov (United States)

Valdemarsen, Thomas; Bannister, Raymond J; Hansen, Pia K; Holmer, Marianne; Ervik, Arne

2012-11-01

We investigated the environmental impact of a deep water fish farm (190 m). Despite deep water and low water currents, sediments underneath the farm were heavily enriched with organic matter, resulting in stimulated biogeochemical cycling. During the first 7 months of the production cycle benthic fluxes were stimulated >29 times for CO(2) and O(2) and >2000 times for NH(4)(+), when compared to the reference site. During the final 11 months, however, benthic fluxes decreased despite increasing sedimentation. Investigations of microbial mineralization revealed that the sediment metabolic capacity was exceeded, which resulted in inhibited microbial mineralization due to negative feed-backs from accumulation of various solutes in pore water. Conclusions are that (1) deep water sediments at 8 °C can metabolize fish farm waste corresponding to 407 and 29 mmol m(-2) d(-1) POC and TN, respectively, and (2) siting fish farms at deep water sites is not a universal solution for reducing benthic impacts. Copyright © 2012 Elsevier Ltd. All rights reserved.

Spatial Variability of Metals in Surface Water and Sediment in the Langat River and Geochemical Factors That Influence Their Water-Sediment Interactions

Directory of Open Access Journals (Sweden)

Wan Ying Lim

2012-01-01

Full Text Available This paper determines the controlling factors that influence the metals’ behavior water-sediment interaction facies and distribution of elemental content (75As, 111Cd, 59Co, 52Cr, 60Ni, and 208Pb in water and sediment samples in order to assess the metal pollution status in the Langat River. A total of 90 water and sediment samples were collected simultaneously in triplicate at 30 sampling stations. Selected metals were analyzed using ICP-MS, and the metals’ concentration varied among stations. Metal concentrations of water ranged between 0.08–24.71 μg/L for As, <0.01–0.53 μg/L for Cd, 0.06–6.22 μg/L for Co, 0.32–4.67 μg/L for Cr, 0.80–24.72 μg/L for Ni, and <0.005–6.99 μg/L for Pb. Meanwhile, for sediment, it ranged between 4.47–30.04 mg/kg for As, 0.02–0.18 mg/kg for Cd, 0.87–4.66 mg/kg for Co, 4.31–29.04 mg/kg for Cr, 2.33–8.25 mg/kg for Ni and 5.57–55.71 mg/kg for Pb. The average concentration of studied metals in the water was lower than the Malaysian National Standard for Drinking Water Quality proposed by the Ministry of Health. The average concentration for As in sediment was exceeding ISQG standards as proposed by the Canadian Sediment Quality Guidelines. Statistical analyses revealed that certain metals (As, Co, Ni, and Pb were generally influenced by pH and conductivity. These results are important when making crucial decisions in determining potential hazardous levels of these metals toward humans.

Genetic relatedness of faecal coliforms and enterococci bacteria isolated from water and sediments of the Apies River, Gauteng, South Africa.

Science.gov (United States)

Ekwanzala, Mutshiene Deogratias; Abia, Akebe Luther King; Ubomba-Jaswa, Eunice; Keshri, Jitendra; Momba, Ndombo Benteke Maggy

2017-12-01

To date, the microbiological quality of river sediments and its impact on water resources are not included in the water quality monitoring assessment. Therefore, the aim of this study was to establish genetic relatedness between faecal coliforms and enterococci isolated from the river water and riverbed sediments of Apies River to better understand the genetic similarity of microorganisms between the sediment and water phases. Indicator bacteria were subjected to a molecular study, which consisted of PCR amplification and sequence analysis of the 16S rRNA and 23S rRNA gene using specific primers for faecal coliforms and enterococci, respectively. Results revealed that the Apies River had high faecal pollution levels with enterococci showing low to moderate correlation coefficient (r 2 values ranged from 0.2605 to 0.7499) compared to the faecal coliforms which showed zero to low correlation (r 2 values ranged from 0.0027 to 0.1407) indicating that enterococci may be better indicator than faecal coliforms for detecting faecal contamination in riverbed sediments. The phylogenetic tree of faecal coliforms revealed a 98% homology among their nucleotide sequences confirming the close genetic relatedness between river water and riverbed sediment isolates. The phylogenetic tree of the enterococci showed that Enterococcus faecalis and Enterococcus faecium are the predominant species found in both river water and riverbed sediments with bootstrap values of ≥99%. A high degree of genetic relatedness between sediment and water isolates indicated a possible common ancestry and transmission pathway. We recommend the microbial monitoring of riverbed sediments as it harbours more diverse microbial community and once resuspended may cause health and environmental problems.

[Distribution of polycyclic aromatic hydrocarbons in water and sediment from Zhoushan coastal area, China].

Science.gov (United States)

Jiang, Min; Tuan, Le Huy; Mei, Wei-Ping; Ruan, Hui-Hui; Wu, Hao

2014-07-01

The spatial and temporal distribution of 16 polycyclic aromatic hydrocarbons (PAHs) has been investigated in water and sediments of Zhoushan coastal area every two months in 2012. The concentrations of total PAHs ranged from 382.3 to 816.9 ng x L(-1), with the mean value of 552.5 ng x L(-1) in water; whereas it ranged from 1017.9 to 3047.1 ng x g(-1), with the mean value of 2 022.4 ng x g(-1) in sediment. Spatial distribution showed that Yangshan and Yanwoshan offshore area had the maximum and minimum of total PAHs contents in water, while the maximum and minimum occurred at Yangshan and Zhujiajian Nansha offshore area in sediment. Temporal distribution revealed that total PAHs contents in water reached the maximum and minimum values in October and June, however in sediments these values were found in August and June, respectively. The PAHs pollution was affected by oil emission, charcoal and coal combustion. Using the biological threshold and exceeded coefficient method to assess the ecological risk of PAHs in Zhoushan coastal area, the result showed that sigma PAHs had a lower probability of potential risk, while there was a higher probability of potential risk for acenaphthylene monomer, and there might be ecological risk for acenaphthene and fluorene. Distribution of PAHs between sediment and water showed that Zhoushan coastal sediment enriched a lot of PAHs, meanwhile the enrichment coefficient (K(d) value) of sediment in Daishan island was larger than that in Zhoushan main island.

Sorption of alkylphenols on Ebro River sediments: Comparing isotherms with field observations in river water and sediments

International Nuclear Information System (INIS)

Navarro, Alicia; Endo, Satoshi; Gocht, Tilman; Barth, Johannes A.C.; Lacorte, Silvia; Barcelo, Damia; Grathwohl, Peter

2009-01-01

This study reports sorption isotherms of the endocrine disruptors nonylphenol (NP) and octylphenol (OP) in three sediment samples from the Ebro River basin (NE Spain), with organic carbon fractions (f OC ) ranging from 0.0035 to 0.082 g OC g -1 . All isotherms were fitted to the Freundlich model with slightly nonlinear exponents ranging from 0.80 to 0.94. The solubility of the compounds as well as the organic carbon (OC) content had the strongest influences on the sorption behavior of these compounds. Comparison of the laboratory-spiked samples with the native contamination of NP of 45 water and concurrent sediment samples resulted in reasonable matches between both data sets, even though the lowest concentrations in the field were not completely reached in laboratory tests. This good agreement indicates that sorption laboratory data can be extrapolated to environmental levels and therefore the distribution of nonylphenol between sediments and water can be predicted with a precision of one order of magnitude. Furthermore, laboratory experiments with simultaneous loading of NP and OP revealed negligible competition for sorption sites at low concentrations. - Laboratory sorption of nonylphenol compared to field concentrations showed good agreements

Sorption of alkylphenols on Ebro River sediments: Comparing isotherms with field observations in river water and sediments

Energy Technology Data Exchange (ETDEWEB)

Navarro, Alicia [Center of Applied Geoscience, University of Tuebingen, Sigwartstrasse 10, 72076 Tuebingen (Germany); Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Jordi Girona 18-26, 08034 Barcelona (Spain)], E-mail: anoqam@iiqab.csic.es; Endo, Satoshi; Gocht, Tilman [Center of Applied Geoscience, University of Tuebingen, Sigwartstrasse 10, 72076 Tuebingen (Germany); Barth, Johannes A.C. [Center of Applied Geoscience, University of Tuebingen, Sigwartstrasse 10, 72076 Tuebingen (Germany); Lehrstuhl fuer Angewandte Geologie, GeoZentrum Nordbayern, Universitaet Erlangen-Nuernberg, Schlossgarten 5, 91054 Erlangen (Germany); Lacorte, Silvia [Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Jordi Girona 18-26, 08034 Barcelona (Spain); Barcelo, Damia [Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Jordi Girona 18-26, 08034 Barcelona (Spain); Institut Catala de Recerca de l' Aigua (ICRA), Parc Cientific i Tecnologic de la Universitat de Girona, Pic de Peguera, 15, 17003 Girona (Spain); Grathwohl, Peter [Center of Applied Geoscience, University of Tuebingen, Sigwartstrasse 10, 72076 Tuebingen (Germany)

2009-02-15

This study reports sorption isotherms of the endocrine disruptors nonylphenol (NP) and octylphenol (OP) in three sediment samples from the Ebro River basin (NE Spain), with organic carbon fractions (f{sub OC}) ranging from 0.0035 to 0.082 g{sub OC} g{sup -1}. All isotherms were fitted to the Freundlich model with slightly nonlinear exponents ranging from 0.80 to 0.94. The solubility of the compounds as well as the organic carbon (OC) content had the strongest influences on the sorption behavior of these compounds. Comparison of the laboratory-spiked samples with the native contamination of NP of 45 water and concurrent sediment samples resulted in reasonable matches between both data sets, even though the lowest concentrations in the field were not completely reached in laboratory tests. This good agreement indicates that sorption laboratory data can be extrapolated to environmental levels and therefore the distribution of nonylphenol between sediments and water can be predicted with a precision of one order of magnitude. Furthermore, laboratory experiments with simultaneous loading of NP and OP revealed negligible competition for sorption sites at low concentrations. - Laboratory sorption of nonylphenol compared to field concentrations showed good agreements.

Uranium concentrations in lake and stream waters and sediments from selected sites in the Susitna River Basin, Alaska

International Nuclear Information System (INIS)

Hill, D.E.

1977-03-01

During the summer of 1976, 141 water and 211 sediment samples were taken from 147 locations in the Susitna River basin in Alaska by the Geophysical Institute of the University of Alaska for the LASL. These samples were taken to provide preliminary information on the uranium concentrations in waters and sediments from the Susitna River basin and to test the analytical methods proposed for the NURE Hydrogeochemical and Stream Sediment Reconnaissance for uranium in Alaska. The uranium determinations resulting from the fluorometric analysis of the water samples and the delayed-neutron counting of the sediment samples are presented. The low levels of uranium in the water samples, many of which were below the detectable limit of the LASL fluorometric technique, indicate that a more sensitive analytical method is needed for the analysis of Alaskan water samples from this area. An overlay showing numbered sample locations and overlays graphically portraying the concentrations of uranium in the water and sediment samples, all at 1:250,000 scale for use with existing USGS topographic sheets, are also provided as plates

Effects of Sediment Chemical Properties on Phosphorus Release Rates in the Sediment-Water Interface of the Steppe Wetlands

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Jing He

2017-11-01

Full Text Available Rising temperature causes a process of phosphorus release, which can be characterized well using phosphorus release rates (VP. The objective of the present study was to investigate the major factors affecting sediment phosphorus release rates through a wetland habitat simulation experiment. The results showed that the VP of different wetland sediments were different and changed with the order of W–R (river wetland > W–L (lake wetland > W–M (grassy marsh wetland > W–A (reservoir wetland. The main driving factors which influenced sediment phosphorus flux velocity in the sediment–water interface were sediment B-SO42−, B-MBN and A-MBP content. Path analysis and determination coefficient analysis indicated the standard multiple regression equation for sediment phosphorus release rates in the sediment–water interface, and each main factor was Y = −0.105 + 0.096X1 + 0.275X2 − 0.010X3 (r = 0.416, p < 0.01, n = 144, where Y is sediment phosphorus release rates; X1 is sediment B-SO42− content; X2 is sediment B-MBN; and X3 is sediment A-MBP content. Sediment B-SO42−, B-MBN and A-MBP content and the interaction between them were the main factors affecting sediment phosphorus release rates in the sediment–water interface. Therefore, these results suggest that soil chemical properties and microbial activities likely play an important role in phosphorus release rates in the sediment–water interface. We hope to provide effective scientific management and control methods for relevant environmental protection departments.

The use of dispersive X-ray fluorescence technique for pollution evaluation of heavy metals in water samples and lake sediments

International Nuclear Information System (INIS)

Vives, Ana Elisa Sirito de; Brienza, Sandra Maria Boscolo

2002-01-01

The energy dispersive X-ray fluorescence technique (EDXRF) was used to determine metals concentration in water and bottom sediments samples in lakes at Santa Gertrudes region, Sao Paulo state, Brazil. The studied area is about 12 ha, with several lakes formed by argil extraction and present high volume of waste which can be dangerous and cause risks to water flora and fauna and also to human health by direct or indirect contact with the residues. To evaluate contamination degree by heavy metals water samples were collected in three lakes, in 2000 July and November, corresponding to the dry and rainy season. In two lakes the sampling procedure were superficial, and in the third lake, sampling was done at central region and in different deepness. Sediment samples were collected at two lakes, in 2000, July (dry) and November (rainy). To determine biologically available metals concentration (no-residual fraction) in the sediment, an acid extraction procedure was used. To quantitative analysis of both samples, metals were pre concentrated by complexation with ammonium pyrrolidine dithiocarbamate. Samples were excited with a X-ray tube with Mo target and Zr filter, operated at 25 kV/10 mA, and X-ray characteristics measure were done with a Si(Li) semi conductor detector. In water samples, were determined the elements Fe, Cu, Zn and Pb. Among the analyzed elements, Fe presented the highest concentration, independent of the sampling local. Was verified that all the analyzed elements presented concentrations below the maximum limit allowed to waters class 2, which may be distributed to domestic provisioning, to primary contact recreation, to vegetables and fruitier plants irrigation and to the natural and/or intensive breeding (agriculture) of species destined to the alimentation. In the sediment samples were determined Fe, Co, Ni, Cu, Zn and Pb, and was observed high contents to the elements Fe, Zn and Pb and relatively low concentrations of Co, Ni and Cu. It was verified

The application of plant tests for sediment evaluation; Der Einsatz von Pflanzentests bei der Sedimentbewertung

Energy Technology Data Exchange (ETDEWEB)

Feiler, U. [Bundesanstalt fuer Gewaesserkunde, Koblenz (Germany); Claus, E. [Bundesanstalt fuer Gewaesserkunde, Berlin (Germany); Heininger, P. [Bundesanstalt fuer Gewaesserkunde, Koblenz (Germany); Bundesanstalt fuer Gewaesserkunde, Berlin (Germany)

2002-07-01

The aim of the present study is to demonstrate that the use of higher plants in biotests for analyses of anthropogenically contaminated sediments yields valuable results, which may be included in a concept for the integrated assessment of waters. The results of this study prove that the selected aquatic plant, Lemna minor, is basically able to indicate contamination. In the aquatic test of the sediment extracts, it showed weak, but very selective, responses to certain classes of contaminants. Fractionating of the sample and subsequent chemical analysis combined with toxicity tests allow to narrow down the groups of substances causing toxic effects. This toxicity was confirmed by analyses of the pore waters and whole sediment samples. Together with other toxicity tests (e.g. standardized bioassays) and combined with biological benthos examinations, an overall judgment can be given for the integrated assessment of waters. (orig.) [German] Ziel der hier vorgestellten Untersuchungen war es zu zeigen, dass der Einsatz von hoeheren Pflanzen in Biotests zur Untersuchung anthropogenen belasteter Sedimente wertvolle Ergebnisse liefert, die in einem Konzept zur integrierten Gewaesserbewertung verwendet werden koennen. Die Ergebnisse dieser Arbeit machen deutlich, dass die ausgewaehlte Wasserpflanze Lemna minor Schadstoffbelastungen grundsaetzlich anzeigt. Im aquatischen Test der Sedimentextrakte weist sie eine zwar schwache, aber sehr selektive Reaktion auf bestimmte Schadstoffklassen auf. Die Fraktionierung der Probe mit anschliessender Stoffanlayse kombiniert mit Toxizitaetstests erlaubt die Eingrenzung der toxisch wirksamen Stoffgruppen. Diese toxische Belastung wurde durch die Porenwasser- und Gesamtsedimentuntersuchung bestaetigt. Zusammen mit weiteren Toxizitaetstests (z.B. standardisierte Biotests) und in Kombination mit benthosbiologischen Untersuchngen ergibt sich eine Gesamtaussage zur integrierten Gewaesserbewertung. (orig.)

A Study on the Environmental Standard of Sediment on the Bottom of the Water

Energy Technology Data Exchange (ETDEWEB)

Lee, Chang Hee; Yoo, Hye Jin [Korea Environment Institute, Seoul (Korea)

2000-12-01

Sediment on the bottom of the water has been considered one of the water pollutants in the environmental management of Korea so treated as a management on pollutants, as you can see the examples in the dragging operation in the polluted sea area. To healthily maintain and conserve the water ecosystem including bottom living things in the water, sediment on the bottom of the water should be recognized as the independent medium, which should maintain the certain quality like the water, the atmosphere, and soil, rather than the source of water pollution. Such recognition means that the management of sediment on the bottom of the water should change the fragmentary goal, centered the post management focusing on the water management, to the ecosystematic goal including the bottom living things. In a point of the view, this study has a great significance to suggest not only the final goal for the management of sediment on the bottom of the water but also the necessity of developing the environmental standard of the sediment on the bottom of the water, which is a standard of the management or judgment in the actual managing the sediment on the bottom of the water - an estimation on the pollution of sediment, a removal of the polluted sediment, a purification of sediment, and an abandonment of the dragged sediment -, and the development measures. Considering the situation that even the basic scheme related to the management of sediment is not prepared in the Government level, the concept of the environmental standard of sediment, the foreign example of the environmental standard of sediment, the current state of the domestic sediment pollution, and the development scheme of the environmental standard in this study must be the important foundation to establish the management system of sediment in the Government level. 121 refs., 10 figs., 45 tabs.

Development of a chronic sediment toxicity test for marine benthic amphipods

International Nuclear Information System (INIS)

DeWitt, T.H.; Redmond, M.S.; Sewall, J.E.; Swartz, R.C.

1992-12-01

The results of the research effort culminated in the development of a research method for assessing the chronic toxicity of contaminated marine and estuarine sediments using the benthic amphipod, Leptocheirus plumulosus. The first chapter describes the efforts at collecting, handling, and culturing four estuarine amphipods from Chesapeake Bay, including L. plumulosus. This chapter includes maps of the distribution and abundance of these amphipods within Chesapeake Bay and methodologies for establishing cultures of amphipods which could be readily adopted by other laboratories. The second chapter reports the development of acute and chronic sediment toxicity test methods for L. plumulosus, its sensitivity to non-contaminant environmental variables, cadmium, two polynuclear aromatic hydrocarbons, and contaminated sediment from Baltimore Harbor, MD. The third chapter reports the authors attempts to develop a chronic sediment toxicity test with Ampelisca abdita

The Role of Water Movement and Spatial Scaling for Measurement of Dissolved Inorganic Nitrogen Fluxes in Intertidal Sediments

Science.gov (United States)

Asmus, R. M.; Jensen, M. H.; Jensen, K. M.; Kristensen, E.; Asmus, H.; Wille, A.

1998-02-01

Fluxes of dissolved inorganic nitrogen (ammonium and nitrate) across the sediment-water interface were determined at intertidal locations in Königshafen, northern Wadden Sea, North Sea. Three different incubation techniques were compared: closed sediment cores (small scale), closed bell jars (medium scale) and an open flow system (Sylt flume, large scale). Water movement in the two closed systems was maintained below the resuspension limit by spinning magnets (cores, incubated in the laboratory) or by transfer of wave action through flexible plastic foil (bell jars,in situ), whereas in the flume system (in situ) water movement was unidirectional, driven by currents and waves. Data sets from several years of core measurements (1992-94), bell jar measurements (1980) and flume campaigns (1990-93) served as the basis for a comparison of dissolved inorganic nitrogen fluxes. Fluxes of ammonium and nitrate were within the same order of magnitude in closed cores and bell jars, while flume rates of ammonium were considerably higher. The high flume rates were caused by advective flushing due to tidal water movement and wave action. The release of ammonium increased significantly with current velocity between 1 and 13 cm s-1. Fluxes of ammonium were higher in sediments withArenicola marinacompared to those without this bioturbating species. The influence of benthic microalgae was evident only in the small and medium scale core and bell jar systems as reduced ammonium release during light exposure. Nitrate was consumed by sediments in both closed systems at a rate proportional to the nitrate concentration in the overlying water. Nitrate fluxes in the large scale Sylt flume were low with an average of only 7% of the ammonium fluxes, probably due to low concentrations in tidal waters during measurements (summer). Both closed, small scale or open, large scale techniques can be applied successfully for benthic flux studies, but the actual choice depends on the purpose of the

EPA Office of Water (OW): Nutrient, Sediment, and Pathogens Water Impairments

Data.gov (United States)

U.S. Environmental Protection Agency — National dataset consisting of a snapshot of 303(d) Listed Impaired Waters combined with Impaired Waters with TMDLs whose parent cause is Nutrients, Sediments, and...

Arsenic and antimony geochemistry of mine wastes, associated waters and sediments at the Giant Mine, Yellowknife, Northwest Territories, Canada

Science.gov (United States)

Fawcett, Skya E.; Jamieson, Heather E.; Nordstrom, D. Kirk; McCleskey, R. Blaine

2015-01-01

Elevated levels of arsenic (As) and antimony (Sb) in water and sediments are legacy residues found downstream from gold-mining activities at the Giant Mine in Yellowknife, Northwest Territories (NWT), Canada. To track the transport and fate of As and Sb, samples of mine-waste from the mill, and surface water, sediment, pore-water, and vegetation downstream of the mine were collected. Mine waste, pore-water, and sediment samples were analyzed for bulk chemistry, and aqueous and solid-state speciation. Sediment and vegetation chemistry were evaluated using scanning electron microscope imaging, synchrotron-based element mapping and electron microprobe analysis. The distributions of As and Sb in sediments were similar, yet their distributions in the corresponding pore-waters were mostly dissimilar, and the mobility of As was greater than that of Sb. Competition for sorption sites is the most likely cause of elevated Sb concentrations in relatively oxidized pore-water and surface water. The aqueous and solid-state speciation of As and Sb also differed. In pore-water, As(V) dominated in oxidizing environments and As(III) in reducing environments. In contrast, the Sb(V) species dominated in all but one pore-water sample, even under reducing conditions. Antimony(III) appears to preferentially precipitate or adsorb onto sulfides as evidenced by the prevalence of an Sb(III)-S secondary solid-phase and the lack of Sb(III)(aq) in the deeper zones. The As(V)–O solid phase became depleted with depth below the sediment–water interface, and the Sb(V)–O phase persisted under relatively reducing conditions. In the surficial zone at a site populated by Equisetum fluviatile (common horsetail), As and Sb were associated with organic material and appeared mobile in the root zone. In the zone below active plant growth, As and Sb were associated primarily with inorganic phases suggesting a release and reprecipitation of these elements upon plant death. The co-existence of reduced

The comparative osmoregulatory ability of two water beetle genera whose species span the fresh-hypersaline gradient in inland waters (Coleoptera: Dytiscidae, Hydrophilidae.

Directory of Open Access Journals (Sweden)

Susana Pallarés

Full Text Available A better knowledge of the physiological basis of salinity tolerance is essential to understanding the ecology and evolutionary history of organisms that have colonized inland saline waters. Coleoptera are amongst the most diverse macroinvertebrates in inland waters, including saline habitats; however, the osmoregulatory strategies they employ to deal with osmotic stress remain unexplored. Survival and haemolymph osmotic concentration at different salinities were examined in adults of eight aquatic beetle species which inhabit different parts of the fresh-hypersaline gradient. Studied species belong to two unrelated genera which have invaded saline waters independently from freshwater ancestors; Nebrioporus (Dytiscidae and Enochrus (Hydrophilidae. Their osmoregulatory strategy (osmoconformity or osmoregulation was identified and osmotic capacity (the osmotic gradient between the animal's haemolymph and the external medium was compared between species pairs co-habiting similar salinities in nature. We show that osmoregulatory capacity, rather than osmoconformity, has evolved independently in these different lineages. All species hyperegulated their haemolymph osmotic concentration in diluted waters; those living in fresh or low-salinity waters were unable to hyporegulate and survive in hyperosmotic media (> 340 mosmol kg(-1. In contrast, the species which inhabit the hypo-hypersaline habitats were effective hyporegulators, maintaining their haemolymph osmolality within narrow limits (ca. 300 mosmol kg(-1 across a wide range of external concentrations. The hypersaline species N. ceresyi and E. jesusarribasi tolerated conductivities up to 140 and 180 mS cm(-1, respectively, and maintained osmotic gradients over 3500 mosmol kg(-1, comparable to those of the most effective insect osmoregulators known to date. Syntopic species of both genera showed similar osmotic capacities and in general, osmotic responses correlated well with upper salinity levels

Assessment of pathogenic bacteria in water and sediment from a water reservoir under tropical conditions (Lake Ma Vallée), Kinshasa Democratic Republic of Congo.

Science.gov (United States)

Mwanamoki, Paola M; Devarajan, Naresh; Thevenon, Florian; Atibu, Emmanuel K; Tshibanda, Joseph B; Ngelinkoto, Patience; Mpiana, Pius T; Prabakar, Kandasamy; Mubedi, Josué I; Kabele, Christophe G; Wildi, Walter; Poté, John

2014-10-01

This study was conducted to assess potential human health risks presented by pathogenic bacteria in a protected multi-use lake-reservoir (Lake Ma Vallée) located in west of Kinshasa, Democratic Republic of Congo (DRC). Water and surface sediments from several points of the Lake were collected during summer. Microbial analysis was performed for Escherichia coli, Enterococcus (ENT), Pseudomonas species and heterotrophic plate counts. PCR amplification was performed for the confirmation of E. coli, ENT, Pseudomonas spp. and Pseudomonas aeruginosa isolated from samples. The results reveal low concentration of bacteria in water column of the lake, the bacterial quantification results observed in this study for the water column were below the recommended limits, according to WHO and the European Directive 2006/7/CE, for bathing water. However, high concentration of bacteria was observed in the sediment samples; the values of 2.65 × 10(3), 6.35 × 10(3), 3.27 × 10(3) and 3.60 × 10(8) CFU g(-1) of dry sediment for E. coli, ENT, Pseudomonas spp. and heterotrophic plate counts, respectively. The results of this study indicate that sediments of the Lake Ma Vallée can constitute a reservoir of pathogenic microorganisms which can persist in the lake. Possible resuspension of faecal indicator bacteria and pathogens would affect water quality and may increase health risks to the population during recreational activities. Our results indicate that the microbial sediment analysis provides complementary and important information for assessing sanitary quality of surface water under tropical conditions.

Investigation on resistance to drought and efficiency of water usage in two range species, Dactylis glomerata and Eragrostis curvula

International Nuclear Information System (INIS)

Jafari, M.; Saiedian, F.; Heydari, H.; Azarnayvand, H.; Farzaneh, Z.

2000-01-01

Determination of water efficiency and resistance to drought in range plants are important factors that have essential role in selection of range development methods. As there is not any comprehensive study in resistance to drought, present research was done with selection of two range species. Selected species were two kinds of Gramineae, namely Dactylis glomerata and Eragrostis curvula. Some parameters such as used water, length, width and number of leaves, dry mass of leaves were studies. Obtained results showed that length and width of leaves were not under stress in irrigation periods, but number of leaves, dry mass of leaf and stem decreased under drought stress. Amount of decrease in Eragrostis curvula was less than Dactylis glomerata Increment of irrigation periods, increased root growth rather than stem, but root growth in Dactylis glomerata was more than Eragrostis curvula for production of dry matter, Dactylis glomerata species has less water requirement and higher water usage efficiency in terms of amount of water usage. In terms of resistance to drought, Eragrostis curvula has more resistance rather than Dactylis glomerata because of high water potential and lower witt ing point

Radioactivity and natural radionuclides distribution in river water, coastal water, sediment and Eichornia Crassipes (Mart) solms and their accumulation factor at Surabaya area

International Nuclear Information System (INIS)

Agus Taftazani; Sumining; Muzakky

2002-01-01

Distributions of radioactivity and natural radionuclides in water, sediment and eichornia crassipes (mart) solms from Surabaya River and coastal area have been evaluated. Five sampling locations were selected to represent fresh water and coastal water environment. The samples consist of water (fresh & coastal), bottom surface sediment and eichornia crassipes (mart) solms. The result showed that the gross-β activity from water environment were lower than the threshold value of Environmental Minister Act. Kep.02/MENKLH/I/1988 (1000 mBq/L) and indicated that β-radio ecological quality of water were still good. But the activity of the gross-α of water environment were higher than the threshold value of Environmental Minister Act. Kep.02/MENKLH/I/1988 (100 mBq/L). The eichornia crassipes (mart) solms (gross) activity were higher than water and sediment activities and indicated that transfer of radio nuclides from water to sediment and organism can be detected in water environment. Two natural radionuclide can be identified by γ-Spectrometric technique, they were K"4"0 and Tl"2"0"8. Generally the distribution factors F_D were smaller than bioaccumulation factor F_B. (author)

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

International Nuclear Information System (INIS)

Kudu, I.B.

2010-01-01

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

Environmental conditions outweigh geographical contiguity in determining the similarity of nifH-harboring microbial communities in sediments of two disconnected marginal seas

Directory of Open Access Journals (Sweden)

Haixia Zhou

2016-07-01

Full Text Available Ecological evidence suggests that heterotrophic diazotrophs fueled by organic carbon respiration in sediments play an important role in marine nitrogen fixation. However, fundamental knowledge about the identities, abundance, diversity, biogeography and controlling environmental factors of nitrogen-fixing communities in open ocean sediments is still elusive. Surprisingly, little is known also about nitrogen-fixing communities in sediments of the more research-accessible marginal seas. Here we report on an investigation of the environmental geochemistry and putative diazotrophic microbiota in the sediments of Bohai Sea, an eutrophic marginal sea of the western Pacific Ocean. Diverse and abundant nifH gene sequences were identified and sulfate-reducing bacteria were found to be the dominant putative nitrogen-fixing microbes. Community statistical analyses suggested bottom water temperature, bottom water chlorophyll a content (or the covarying turbidity and sediment porewater Eh (or the covarying pH as the most significant environmental factors controlling the structure and spatial distribution of the putative diazotrophic communities, while sediment Hg content, sulfide content and porewater SiO32--Si content were identified as the key environmental factors correlated positively with the nifH gene abundance in Bohai Sea sediments. Comparative analyses between the Bohai Sea and the northern South China Sea identified a significant composition difference of the putative diazotrophic communities in sediments between the shallow-water (estuarine and nearshore and deep-water (offshore and deep-sea environments, and sediment porewater dissolved oxygen content, water depth and in situ temperature as the key environmental factors tentatively controlling the species composition, community structure and spatial distribution of the marginal sea sediment nifH-harboring microbiota. This confirms the ecophysiological specialization and niche differentiation

Geochemical distribution and fate of arsenic in water and sediments of rivers from the Hokusetsu area, Japan

Directory of Open Access Journals (Sweden)

Emilie Even

2017-02-01

New hydrological insights for the region: The geochemical mapping showed that As in river water exceeded the maximum limit concentration of 10 ppb in several places. The highest As levels (waters and sediments correlated well with the surface geologies, concentrating in a halo around granitic intrusion and nearby faults. The isotopic analysis of sulfur revealed the occurrence of two kinds of sulfide mineralizations responsible for As contamination: one from Late Paleozoic submarine volcanism in sedimentary rocks, and one from Late Cretaceous igneous activities in contact-metamorphosed rocks disseminated with sulfides. The transport of As along river courses occurred mainly as a dissolved species rather than absorbed on Fe/Mn/Al particles, signifying the least role of iron oxy-hydroxides in As adsorption.

Distribution of Radioisotopes between Phytoplankton, Sediment and Sea Water in a Dialysis Compartment System

International Nuclear Information System (INIS)

Dawson, R.; Duursma, E.K.

1976-01-01

The distribution of the radioisotopes 36 Cl, 54 Mn, 59 Fe, 60 Co, 65 Zn, 90 Sr, 106 Ru, 109 Cd, 110 mAg, 137 Cs, 144 Ce, 147 Pm and 204 Tl between sea water, Mediterranean sediment in suspension, and the phytoplankton species Phaeodactylum tricornutum was studied by using a competitive technique in which the various phases were separated by dialysis membranes. The radioisotopes were introduced into the sea water compartment and the radionuclide uptake by sediment and phytoplankton occurred in the adjoining compartments after the isotopes had diffused through the membranes. The diffusion through membranes is time dependent and related to the hydrated ion radii of the elements in solution. Chelation of the elements by organic matter from sewage may hamper this diffusion, although the complexing molecules themselves can pass through the membrane. The laboratory experiments showed that the uptake of radionuclides by sediments and phytoplankton in suspension did not occur independently of each other but in competition relative to the different affinities to the sediment and phytoplankton and relative to the concentrations of the particulate materials themselves. On examination of the distribution coefficients, the isotopes 90Sr, 110m Ag, 204 Ti and in particular 109 Cd, had higher affinities towards Phaeodactylum tricornutum than towards the Mediterranean sediment. The isotopes 54 Mn, 60 Co and 137 Cs had lower distribution coefficients with the phytoplankton than with sediment and in the case of 59 Fe, 65 Zn, l06 Ru, l 4 Ce and 147 Pm, the distribution coefficients were similar for both phytoplankton and sediment. Taking into account that many more factors play a role in the natural aquatic environment, the distribution pattern between water, plankton and sediment in suspension can be approximated by calculating the percentage distribution in the 3 phases. Those percentages are dependent on 2 parameters, being the distribution coefficients and the concentrations of the

Interstitial water chemistry and nutrients fluxes from tropical intertidal sediment

Digital Repository Service at National Institute of Oceanography (India)

Ram, A.; Zingde, M.D.

temporal changes in relation to their con- centrations in the overlying creek water. The high chlorinity creek water infiltrating in the bed after September, progres- sively pushed down the monsoonal low chlorinity water trapped in the sediment resulting....4-2.5%), the trend of decreasing con- centration with depth indicated some accumulation in the sediment over the years. The 1.0-2.5% Corgin core 2 commonly occurs in silty-clay sediment along the centra] west coast of India16 even in areas where there is no apparent...

Sediment-water distribution of perfluorooctane sulfonate (PFOS) in Yangtze River Estuary

International Nuclear Information System (INIS)

Pan Gang; You Chun

2010-01-01

Analysis of Perfluorooctane sulfonate (PFOS) distribution in water and sediment in Yangtze River Estuary showed that the estuary was a sink for PFOS. Salinity was an important parameter in controlling the sediment-water interactions and the fate or transport of PFOS in the aquatic environment. As the salinity (S per mille ) increased from 0.18 to 3.31, the distribution coefficient (K d ) between sediment and water linearly increased from 0.76 to 4.70 L g -1 . The study suggests that PFOS may be carried with the river water and transported for long distances before it reaches to the sea and largely scavenged to the sediment in the estuaries due to the dramatic change in salinity. - PFOS may be largely scavenged to the sediment in estuaries due to the dramatic change in salinity during its transport from lands to oceans.

Experiments on sedimentation of particles in a water pool with gas inflow

Energy Technology Data Exchange (ETDEWEB)

Kim, Eun Ho; Jung, Woo Hyun; Park, Jin Ho; Park, Hyun Suk; Moriyama, Kiyofumi [Div. of Advanced Nuclear Engineering, Pohang University of Science and Technology, Pohang (Korea, Republic of)

2016-04-15

During the late phase of severe accidents of light water reactors, a porous debris bed is expected to develop on the bottom of the flooded reactor cavity after breakup of the melt in water. The geometrical configuration, i.e., internal and external characteristics, of the debris bed is significant for the adequate assessment of the coolability of the relocated corium. The internal structure of a debris bed was investigated experimentally using the DAVINCI (Debris bed research Apparatus for Validation of the bubble-Induced Natural Convection effect Issue) test facility. Particle sedimentation under the influence of a two-phase natural convection flow due to the decay heat in the debris bed was simulated by dropping various sizes of particles into a water vessel with air bubble injection from the bottom. Settled particles were collected and sieved to obtain the particle mass, size distribution in the radial and axial positions, and the bed porosity and permeability. The experimental results showed that the center part of the particle bed tended to have larger particles than the peripheral area. For the axial distribution, the lower layer had a higher fraction of larger particles. As the sedimentation progressed, the size distribution in the upper layers can shift to larger sizes because of the higher vapor generation rate and stronger flow intensity.

Assessing natural and anthropogenic influences on water discharge and sediment load in the Yangtze River, China.

Science.gov (United States)

Zhao, Yifei; Zou, Xinqing; Liu, Qing; Yao, Yulong; Li, Yali; Wu, Xiaowei; Wang, Chenglong; Yu, Wenwen; Wang, Teng

2017-12-31

The water discharge and sediment load of rivers are changing substantially under the impacts of climate change and human activities, becoming a hot issue in hydro-environmental research. In this study, the water discharge and sediment load in the mainstream and seven tributaries of the Yangtze River were investigated by using long-term hydro-meteorological data from 1953 to 2013. The non-parametric Mann-Kendall test and double mass curve (DMC) were used to detect trends and abrupt change-points in water discharge and sediment load and to quantify the effects of climate change and human activities on water discharge and sediment load. The results are as follows: (1) the water discharge showed a non-significant decreasing trend at most stations except Hukou station. Among these, water discharge at Dongting Lake and the Min River basin shows a significant decreasing trend with average rates of -13.93×10 8 m 3 /year and -1.8×10 8 m 3 /year (PYangtze River. (2) No significant abrupt change-points were detected in the time series of water discharge for all hydrological stations. In contrast, significant abrupt change-points were detected in sediment load, most of these changes appeared in the late 1980s. (3) The water discharge was mainly influenced by precipitation in the Yangtze River basin, whereas sediment load was mainly affected by climate change and human activities; the relative contribution ratios of human activities were above 70% for the Yangtze River. (4) The decrease of sediment load has directly impacted the lower Yangtze River and the delta region. These results will provide a reference for better resource management in the Yangtze River Basin. Copyright © 2017 Elsevier B.V. All rights reserved.

Investigation of Composition of Particle Size in Sediments of Stormwater Sedimentation Tank

Directory of Open Access Journals (Sweden)

Daiva Laučytė

2011-04-01

Full Text Available The main object for the storm water runoff treatment is to remove suspended solids before the storm water runoff is discharged into surface waters. Therefore the sedimentation tank is the most often used treatment facility. In order to optimise the sedimentation, the tendency of particle size distribution in bottom sediments must be known. Two similar size storm water runoff sedimentation tanks in Vilnius city were selected for the analysis of the particle size distribution in sediments. The composite samples of drained storm water runoff sediments were collected at the sedimentation tanks located in the districts of Verkiai and Karoliniskes on the 2nd of June, 2008. The analyses of grain size distribution were performed according the standard ISO/TS 17892-4:2004. The results showed that the particles with the particle size of 1–2 mm were obtained up to 10 m from the inlet and the particles with the size of 0,01–0,05 mm mainly were obtained close to the outlet of sedimentation tank. It is recommended to divide the sedimentation tank in two parts in order to get proper management of sediments: the particles that size is 1–10 mm could be managed as waste from grit chambers and particles of smaller size could be managed as primary sludge.Article in Lithuanian

Leaf gas exchange, fv/fm ratio, ion content and growth conditions of the two moringa species under magnetic water treatment

International Nuclear Information System (INIS)

Hasan, M.M.; Alharby, H.F.; Hajar, A.; Hakeem, K.R.

2017-01-01

The current greenhouse experiment investigates the role of magnetic water on the two Moringa species (Moringa oleifera and Moringa peregrina). Both species were exposed to the magnetic field (30 mT). The magnetic water increased the plant height, leaf number, leaflet number, and internode distances in both the species, respectively. Relative water content (RWC) and leaf area in both the species showed changes under magnetic water treatment. The results showed in magnetic water treatment, the leaf gas exchange parameters such as assimilation (A), stomatal conductance (gs), transpiration rate (E), and vapor pressure deficit (VPD) were increased. Similarly, Photosynthetic pigments (Chl a, Chl b, Chl (a+b), Carotenoids), photosynthetic water use efficiency (WUE) were also increased significantly. Magnetized water had also significant effects on the maximal efficiency of PSII photochemistry (Fv/Fm). Our study suggested that magnetic water treatment could be used as an environment-friendly technology for improving the growth and physiology of Moringa species. In addition, this technology could be further incorporated into the traditional methods of agriculture for the improvement of crop plants, particularly in the arid and sub-arid areas of the world. (author)

Modeling the fate of p,p'-DDT in water and sediment of two typical estuarine bays in South China: Importance of fishing vessels' inputs.

Science.gov (United States)

Fang, Shu-Ming; Zhang, Xianming; Bao, Lian-Jun; Zeng, Eddy Y

2016-05-01

Antifouling paint applied to fishing vessels is the primary source of dichloro-diphenyl-trichloroethane (DDT) to the coastal marine environments of China. With the aim to provide science-based support of potential regulations on DDT use in antifouling paint, we utilized a fugacity-based model to evaluate the fate and impact of p,p'-DDT, the dominant component of DDT mixture, in Daya Bay and Hailing Bay, two typical estuarine bays in South China. The emissions of p,p'-DDT from fishing vessels to the aquatic environments of Hailing Bay and Daya Bay were estimated as 9.3 and 7.7 kg yr(-1), respectively. Uncertainty analysis indicated that the temporal variability of p,p'-DDT was well described by the model if fishing vessels were considered as the only direct source, i.e., fishing vessels should be the dominant source of p,p'-DDT in coastal bay areas of China. Estimated hazard quotients indicated that sediment in Hailing Bay posed high risk to the aquatic system, and it would take at least 21 years to reduce the hazards to a safe level. Moreover, p,p'-DDT tends to migrate from water to sediment in the entire Hailing Bay and Daya Bay. On the other hand, our previous research indicated that p,p'-DDT was more likely to migrate from sediment to water in the maricultured zones located in shallow waters of these two bays, where fishing vessels frequently remain. These findings suggest that relocating mariculture zones to deeper waters would reduce the likelihood of farmed fish contamination by p,p'-DDT. Copyright © 2016 Elsevier Ltd. All rights reserved.

Sustainability of Water Reclamation: Long-Term Recharge with Reclaimed Wastewater Does Not Enhance Antibiotic Resistance in Sediment Bacteria

Directory of Open Access Journals (Sweden)

Jean E. McLain

2014-03-01

Full Text Available Wastewater reclamation for municipal irrigation is an increasingly attractive option for extending water supplies. However, public health concerns include the potential for development of antibiotic resistance (AR in environmental bacteria after exposure to residual pharmaceuticals in reclaimed water. Though scientific studies have reported high levels of AR in soils irrigated with wastewater, these works often fail to address the soil resistome, or the natural occurrence of AR. This study compared AR patterns in sediment Enterococcus isolated from water storage basins containing either reclaimed water or groundwater in central Arizona. Resistance to 16 antibiotics was quantified in isolates to a depth of 30 cm. Results reveal high levels of resistance to certain antibiotics, including lincomycin, ciprofloxacin, and erythromycin, exists in sediments regardless of the water source (groundwater, reclaimed water, and higher AR was not detectable in reclaimed water sediments. Furthermore, multiple-antibiotic-resistance (MAR was substantially reduced in isolates from reclaimed water sediments, compared to freshwater sediment isolates. Comparing the development of AR in sediment bacteria at these two sites will increase awareness of the environmental and public health impacts of using reclaimed water for irrigation of municipal areas, and illustrates the necessity for control sites in studies examining AR development in environmental microbiota.

A review of the persistence of long-lived radionuclides in the marine environment - sediment/water interactions

International Nuclear Information System (INIS)

Edgington, D.N.

1981-01-01

There is a considerable international concern regarding the advisability and safety of the disposal or dumping of radioactive wastes in the oceans. The assimilation capacity of the ocean for long-lived radionuclides will depend largely on the maximum concentrations that can be safely or agreeably contained within it. Since the mechanisms for removal or control are radioactive decay or association with particles and burial in the sediments, an understanding of the processes involved, in sediment-particle/water interactions, at the sediment/water interface, and within the sediment is extremely important. During the last 35 years there have been considerable inputs of long-lived radionuclides into the oceans as a result of weapons testing, routine releases from fuels reprocessing plants and operating nuclear reactors, and accidental releases from a variety of sources; this provides an excellent opportunity to study their behaviour in the oceans. Thus, the purpose here is to synthesize the present state of our knowledge of sediment/water interactions from studies, mainly of plutonium and americium, conducted in a wide range of environments from the Arctic to the tropics. (author)

Biodiversity effects of benthic ecosystem engineers on the spatial patterns of sediment CH4 concentration in an urban Neotropical coastal lagoon

Directory of Open Access Journals (Sweden)

Adriano Caliman

Full Text Available AIM: Biodiversity of sediment bioturbators has been shown to be important for to the magnitude and stability of benthic-pelagic processes. However, no study to date has evaluated the importance of the biodiversity of benthic invertebrate bioturbators to the spatial patterns of sediment CH4 concentration ([CH4]. Here we conducted a laboratorial experiment to test the following predictions: (1 Bioturbator species richness will reduce the sediment [CH4]; (2 individual bioturbator species (i.e. species composition will have different effects on sediment [CH4]; (3 and both the effects of bioturbator species richness and composition on sediment [CH4] will be dependent on sediment depth. METHODS: We manipulated the number and composition of three functional divergent benthic invertebrate bioturbators species that are widespread in South Atlantic coastal lagoons, in laboratorial sediment chambers containing the sediment and water of an urban impacted coastal lagoon RESULTS: Bioturbator species richness had no overall significant effect on sediment [CH4] when comparisons of sediment [CH4] were made among species richness levels. However, bioturbator species richness significantly reduced sediment [CH4] when species richness levels were compared to the control (defaunated treatments, but this effect was significant only at the deepest sediment layer. Furthermore, bioturbator species composition had significant, but distinct effects on the patterns of reduction in sediment [CH4], depending on the sediment depth and the bioturbator species. CONCLUSIONS: We conclude that both the number and composition of bioturbator species are important to determine the effects of benthic bioturbators on spatial patterns of sediment [CH4], but the strength of these effects depend on species traits that determine interspecific interactions strength across the sediment vertical niche space.

Lake Mixing Regime Influences Arsenic Transfer from Sediments into the Water Column and Uptake in Plankton

Science.gov (United States)

Gawel, J.; Barrett, P. M.; Hull, E.; Burkart, K.; McLean, J.; Hargrave, O.; Neumann, R.

2017-12-01

The former ASARCO copper smelter in Ruston, WA, now a Superfund site, contaminated a large area of the south-central Puget Sound region with arsenic over its almost 100-year history. Arsenic, a priority Superfund contaminant and carcinogen, is a legacy pollutant impacting aquatic ecosystems in urban lakes downwind of the ASARCO emissions stack. We investigated the impact of lake mixing regime on arsenic transfer from sediments into lake water and aquatic biota. We regularly collected water column and plankton samples from four study lakes for two years, and deployed sediment porewater peepers and sediment traps to estimate arsenic flux rates to and from the sediments. In lakes with strong seasonal stratification, high aqueous arsenic concentrations were limited to anoxic hypolimnetic waters while low arsenic concentrations were observed in oxic surface waters. However, in polymictic, shallow lakes, we observed elevated arsenic concentrations throughout the entire oxic water column. Sediment flux estimates support higher rates of arsenic release from sediments and vertical transport. Because high arsenic in oxic waters results in spatial overlap between arsenate, a phosphate analog, and lake biota, we observed enhanced trophic transfer of arsenic in polymictic, shallow study lakes, with higher arsenic accumulation (up to an order of magnitude) in both phytoplankton and zooplankton compared to stratified lakes. Chemical and physical mechanisms for higher steady-state arsenic concentrations will be explored. Our work demonstrates that physical mixing processes coupled with sediment/water redox status exert significant control over bioaccumulation, making shallow, periodically-mixed urban lakes uniquely vulnerable to environmental and human health risks from legacy arsenic contamination.

Water and sediment transport modeling of a large temporary river basin in Greece.

Science.gov (United States)

Gamvroudis, C; Nikolaidis, N P; Tzoraki, O; Papadoulakis, V; Karalemas, N

2015-03-01

The objective of this research was to study the spatial distribution of runoff and sediment transport in a large Mediterranean watershed (Evrotas River Basin) consisting of temporary flow tributaries and high mountain areas and springs by focusing on the collection and use of a variety of data to constrain the model parameters and characterize hydrologic and geophysical processes at various scales. Both monthly and daily discharge data (2004-2011) and monthly sediment concentration data (2010-2011) from an extended monitoring network of 8 sites were used to calibrate and validate the Soil and Water Assessment Tool (SWAT) model. In addition flow desiccation maps showing wet and dry aquatic states obtained during a dry year were used to calibrate the simulation of low flows. Annual measurements of sediment accumulation in two reaches were used to further calibrate the sediment simulation. Model simulation of hydrology and sediment transport was in good agreement with field observations as indicated by a variety of statistical measures used to evaluate the goodness of fit. A water balance was constructed using a 12 year long (2000-2011) simulation. The average precipitation of the basin for this period was estimated to be 903 mm yr(-1). The actual evapotranspiration was 46.9% (424 mm yr(-1)), and the total water yield was 13.4% (121 mm yr(-1)). The remaining 33.4% (302 mm yr(-1)) was the amount of water that was lost through the deep groundwater of Taygetos and Parnonas Mountains to areas outside the watershed and for drinking water demands (6.3%). The results suggest that the catchment has on average significant water surplus to cover drinking water and irrigation demands. However, the situation is different during the dry years, where the majority of the reaches (85% of the river network are perennial and temporary) completely dry up as a result of the limited rainfall and the substantial water abstraction for irrigation purposes. There is a large variability in the

Effects of sediment organic matter quality on bioaccumulation, degradation, and distribution of pyrene in two macrofaunal species and their surrounding sediment

DEFF Research Database (Denmark)

Granberg, Maria E.; Selck, Henriette

2007-01-01

Sediment dwelling macrofauna (infauna) are important vectors for the transfer of sediment-associated contaminants to higher trophic levels. Sedimenting organic matter constitutes an important food source for all benthic organisms and changes seasonally in terms of quantity and quality. Sediment...... imply that bioaccumulation and trophic transfer of sediment-associated PAH should increase following fresh organic matter input, e.g. after sedimentation of phytoplankton blooms. We stress the importance of considering behavioural characteristics of infauna and the trophic situation of the system when...

Testing a two-scale focused conservation strategy for reducing phosphorus and sediment loads from agricultural watersheds

Science.gov (United States)

Carvin, Rebecca; Good, Laura W.; Fitzpatrick, Faith A.; Diehl, Curt; Songer, Katherine; Meyer, Kimberly J.; Panuska, John C.; Richter, Steve; Whalley, Kyle

2018-01-01

This study tested a focused strategy for reducing phosphorus (P) and sediment loads in agricultural streams. The strategy involved selecting small watersheds identified as likely to respond relatively quickly, and then focusing conservation practices on high-contributing fields within those watersheds. Two 5,000 ha (12,360 ac) watersheds in the Driftless Area of south central Wisconsin, previously ranked in the top 6% of similarly sized Wisconsin watersheds for expected responsiveness to conservation efforts to reduce high P and sediment loads, were chosen for the study. The stream outlets from both watersheds were monitored from October of 2006 through September of 2016 for streamflow and concentrations of sediment, total P, and, beginning in October of 2009, total dissolved P. Fields and pastures having the highest potential P delivery to the streams in each watershed were identified using the Wisconsin P Index (Good et al. 2012). After three years of baseline monitoring (2006 to 2009), farmers implemented both field- and farm-based conservation practices in one watershed (treatment) as a means to reduce sediment and P inputs to the stream from the highest contributing areas, whereas there were no out-of-the-ordinary conservation efforts in the second watershed (control). Implementation occurred primarily in 2011 and 2012. In the four years following implementation of conservation practices (2013 through 2016), there was a statistically significant reduction in storm-event suspended sediment loads in the treatment watershed compared to the control watershed when the ground was not frozen (p = 0.047). While there was an apparent reduction in year-round suspended sediment event loads, it was not statistically significant at the 95% confidence level (p = 0.15). Total P loads were significantly reduced for runoff events (p < 0.01) with a median reduction of 50%. Total P and total dissolved P concentrations for low-flow conditions were also significantly reduced (p

Analysis of heavy metals concentration in water and sediment in the Hara biosphere reserve, southern Iran.

Science.gov (United States)

Nowrouzi, Mohsen; Mansouri, Borhan; Nabizadeh, Sahar; Pourkhabbaz, Alireza

2014-02-01

This study determined the concentration of heavy metals (Al, Cr, Cu, and Zn) in water and sediments at nine sites in the Hara biosphere reserve of southern Iran during the summer and winter 2010. Determination of Al, Cr, Cu, and Zn in water was carried out by graphite furnace atomic absorption spectrometer (Shimadzu, AA 610s) and in sediment by flame atomic absorption spectrometer (Perkin Elmer, AA3030). Results showed that the heavy metal concentrations in the water samples decreased in the sequence of Zn > Al > Cu > Cr, while in sediment samples were Cr > Zn > Cu > Al. Data analysis indicated that with the exception of Al, there was a Pearson's correlation coefficient between pH and Cu, Zn, and Cr at α = 0.01, 0.05, and 0.001 in sediment (in winter), respectively. There were also significant differences between heavy metals of Cr, Cu, and Zn during the two seasons (p < 0.001) in the water and sediment.

The Effect of Aquatic Vegetation on Water Quality in the Everglades Agricultural Area Canals

Science.gov (United States)

Gomez, S. M.; Bhadha, J. H.; Lang, T. A.; Josan, M. S.; Daroub, S. H.

2011-12-01

The canals in the Everglades Agricultural Area contain an abundance of floating aquatic vegetation (FAV) and submerged aquatic vegetation (SAV). These FAV flourish in waters with high phosphorus (P) concentrations and prevent the co-precipitation of P with the limestone bedrock (CaCO3). To test the effects of FAV and SAV and the presence of sediments on water quality in the canals, a lysimeter study was set up and stocked with FAV (water lettuce) and SAV (filamentous algae). There were four treatments with four replicates Treatment one contained limerock, sediment from the canals, and FAV. Treatment two contained limerock, sediment, and SAV. Treatment three contained limerock and FAV, while treatment four had limerock and SAV. After 7 days, the buckets were drained and replaced the water with new, high P canal water. Water samples were taken at 0, 0.25, 1, 3, and 7 days after each weekly water exchange. To test water quality soluble reactive P, total P, total dissolved P, Ca, and total organic carbon were analyzed. The impact of FAV and SAV and canal sediments on water quality will be discussed. We hypothesize water lettuce treatments will initially result in a reduction in P-concentration in all species, but will only serve as a short-term sink because of their high turn-over rate and production of labile high-P sediment (floc). In addition, we hypothesize the treatments with no sediment will have more P reduction because of the availability for P to co-precipitate with CaCO3.

Comparative study of plutonium and americium bioaccumulation from two marine sediments contaminated in the natural environment

Energy Technology Data Exchange (ETDEWEB)

Hamilton, T.F.; Smith, J.D. (Melbourne Univ., Parkville (Australia). Dept. of Inorganic Chemistry); Fowler, S.W.; LaRosa, J.; Holm, E. (International Atomic Energy Agency, Monaco-Ville (Monaco). Lab. of Marine Radioactivity); Aarkrog, A.; Dahlgaard, H. (Risoe National Lab., Roskilde (Denmark))

1991-01-01

Plutonium and americium sediment-animal transfer was studied under controlled laboratory conditions by exposure of the benthic polychaete Nereis diversicolor (O. F. Mueller) to marine sediments contaminated by a nuclear bomb accident (near Thule, Greenland) and nuclear weapons testing (Enewetak Atoll). In both sediment regimes, the bioavailability of plutonium and {sup 241}Am was low, with specific activity in the tissues <1% (dry wt) than in the sediments. Over the first three months, a slight preference in transfer of plutonium over {sup 241}Am occurred and {sup 241}Am uptake from the Thule sediment was enhanced compared to that from lagoon sediments of Enewetak Atoll. Autoradiography studies indicated the presence of hot particles of plutonium in the sediments. The results highlight the importance of purging animals of their gut contents in order to obtain accurate estimates of transuranic transfer from ingested sediments into tissue. It is further suggested that enhanced transuranic uptake by some benthic species could arise from ingestion of highly activity particles and organic-rich detritus present in the sediments. (author).

Characteristic sediment and water column chlorophyll-a in the sea cucumber’s Paracaudina sp. habitat on the Kenjeran Water, Surabaya

Science.gov (United States)

Widianingsih, W.; Zaenuri, M.; Anggoro, S.; Kusumaningrum, H. P.; Hartati, R.

2018-03-01

The study of characteristic sediment and water column chlorophyll-a has an important role in the sea cucumber habitat. Sediment chlorophyll-a represents a productivity primer for the benthic community. This research has a purpose to investigate characteristic sediment and water column chlorophyll-a on the Kenjeran water, Surabaya. Sediment samples were collected by the ekman grab for analysis, grain size and nutrient. The sample for sediment chlorophyll-a was taken by core sampler. The water samples were taken with Nansen Bottles. According to the research result, the values of sediment chlorophyll-a at station 10, 11 and 12 were higher than the other stations. In contrast, the value of chlorophyll-a in the column water had almost the same value for each station. The sediment chlorophyll-a value on clay and silt sediment type was higher than the fine sand and coarse sediment type. The suitable habitat characteristic for Paracaudina sp. was clay and silt sediment with sediment chlorophyll concentration ranging from 347.82 mg·m-2 to 1135.52 mg·m-2.

Testing the effects of in-stream sediment sources and sinks on simulated watershed sediment yield using the coupled U.S. Army Corps of Engineers GSSHA Model and SEDLIB Sediment Transport Library

Science.gov (United States)

Floyd, I. E.; Downer, C. W.; Brown, G.; Pradhan, N. R.

2017-12-01

The Gridded Surface Subsurface Hydrologic Analysis (GSSHA) model is the US Army Corps of Engineers' (USACE)'s only fully coupled overland/in-stream sediment transport model. While the overland sediment transport formulation in GSSHA is considered state of the art, the existing in-stream sediment transport formulation is less robust. A major omission in the formulation of the existing GSSHA in-stream model is the lack of in-stream sources of fine materials. In this effort, we enhanced the in-stream sediment transport capacity of GSSHA by linking GSSHA to the SEDLIB sediment transport library. SEDLIB was developed at the Coastal and Hydraulics Laboratory (CHL) under the System Wide Water Resources Program (SWWRP) and Flood and Coastal (F&C) research program. It is designed to provide a library of sediment flux formulations for hydraulic and hydrologic models, such as GSSHA. This new version of GSSHA, with the updated in-stream sediment transport simulation capability afforded by the linkage to SEDLIB, was tested in against observations in an experimental watershed that had previously been used as a test bed for GSSHA. The results show a significant improvement in the ability to model in-stream sources of fine sediment. This improved capability will broaden the applicability of GSSHA to larger watersheds and watersheds with complex sediment dynamics, such as those subjected to fire hydrology.

Agar Sediment Test for Assessing the Suitability of Organic Waste Streams for Recovering Nutrients by the Aquatic Worm Lumbriculus variegatus

NARCIS (Netherlands)

Laarhoven, Bob; Elissen, H.J.H.; Temmink, H.; Buisman, C.J.N.

2016-01-01

An agar sediment test was developed to evaluate the suitability of organic waste streams from the food industry for recovering nutrients by the aquatic worm Lumbriculus variegatus (Lv). The effects of agar gel, sand, and food quantities in the sediment test on worm growth, reproduction, and water

Water and suspended sediment division at a stratified tidal junction

NARCIS (Netherlands)

Buschman, F.A.; Vegt, M. van der; Hoitink, A.J.F.; Hoekstra, P.

2013-01-01

Tidal junctions play a crucial role in the transport of water, salt, and sediment through a delta distributary network. Water, salt and sediment are exchanged at tidal junctions, thereby influencing the transports in the connecting branches and the overall dynamics of the system. This paper

Identification of water soluble and particle bound compounds causing sublethal toxic effects. A field study on sediments affected by a chlor-alkali industry

International Nuclear Information System (INIS)

Bosch, Carme; Olivares, Alba; Faria, Melissa; Navas, Jose M.; Olmo, Ivan del; Grimalt, Joan O.; Pina, Benjamin; Barata, Carlos

2009-01-01

A combination of cost effective sublethal Daphnia magna feeding tests, yeast- and cell culture-based bioassays and Toxicity Identification Evaluation (TIE) procedures was used to characterize toxic compounds within sediments collected in a river area under the influence of the effluents from a chlor-alkali industry (Ebro River, NE Spain). Tests were designed to measure and identify toxic compounds in the particulate and filtered water fractions of sediment elutriates. The combined use of bioassays responding to elutriates and dioxin-like compounds evidenced the existence of three major groups of hazardous contaminants in the most contaminated site: (A) metals such as cadmium and mercury bound to sediment fine particles that could be easily resuspended and moved downstream, (B) soluble compounds (presumably, lye) able to alkalinize water to toxic levels, and (C) organochlorine compounds with high dioxin-like activity. These results provided evidence that elutriate D. magna feeding responses can be used as surrogate assays for more tedious chronic whole sediment tests, and that the incorporation of such tests in sediment TIE procedures may improve the ability to identify the toxicity of particle-bound and water-soluble contaminants in sediments.

Radioactivity and Natural Radio nuclides Distribution in River Water, Coastal Water, Sediment and Eichornia Crassipes (Mart) Sloms and Their Accumulation Factor at Surabaya Area

International Nuclear Information System (INIS)

Agus Taftazani; Sumining; Muzakky

2002-01-01

Distribution of radioactivity and natural radionuclide in water, sediment and eichornia crassipes (mart) sloms from Surabaya river and coastal area have been evaluated. Five sampling locations were selected to represent fresh water and coastal water environment. The samples consist of water (fresh and coastal), bottom surface sediment and eichornia crassipes (mart) sloms The result showed that the gross-β activity from water environment were lower than the threshold value of Environmental Minister Act. Kep.02/MENKLH/I/1988 (1000 mBq/L) and indicated that β-radioecological quality of water were still good. But the activity of the gross-α of water environment were higher than the threshold value of Environmental Minister Act. Kep.02/MENKLH/I/1988 (100 mBq/L). The eichornia crassipes (mart) sloms (gross) activity were higher than water and sediment activities and indicated that transfer of radionuclides from water to sediment and organism can be detected in water environment. Two natural radionuclides can be identified by γ-Spectrometric technique, they were K-40 and TI-208. Generally the distribution factor F D were smaller than bioaccumulation factor F B . (author)

Design Development of SMART ECC Water Asymmetric Two-phase choking test facility

Energy Technology Data Exchange (ETDEWEB)

Cho, Young Il; Cho, Seok; Ko, Yung Joo; Shin, Yong Cheol; Kwon, Tae Soon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2011-05-15

SMART pressurized water reactor type is different from the existing integral NSSS commercial pressurized water reactor system which is equipped with the main features. In addition RCS piping is removed and the feature of the SBLOCA is a major design break accident. The TASS / SMR code is analyzed SMART SBLOCA. In order to verify analysis code, SMART analysis for verification of conservatism is promoting using data for experiments with Integral Effect Test and Separate Effect. In this paper, the design feature of the SWAT (SMART ECC Water Asymmetric Two-phase choking test facility) is described. SWAT is linearly reduced to a 1/5 ratio while the geometrical shape is conserved. In major shape of SMART ECC injection performance test, distortions which caused by gravitational effects are minimized. Because both the emergency core cooling water injection nozzle height and the break nozzle height match the RCP Suction Nozzle height in test section of the main forms. The main part of the test section is SG-side upper down-comer. The boundary conditions are saturated steam and water flow condition and drain flow rate to control the collapsed water level in the down-comer

Kato-Katz and Lumbreras rapid sedimentation test to evaluate helminth prevalence in the setting of a school-based deworming program

OpenAIRE

Lopez, Martha; Morales, Maria Luisa; Konana, Monisha; Hoyer, Paige; Pineda-Reyes, Roberto; White, Arthur Clinton; Garcia, Hector Hugo; Lescano, Andres Guillermo; Gotuzzo, Eduardo; Cabada, Miguel Mauricio

2016-01-01

The sensitivity of the Kato-Katz test is suboptimal for the evaluation of intestinal helminth prevalence. Moreover, during mass deworming, as helminth egg burden decreases, the sensitivity is likely to decrease. The Lumbreras rapid sedimentation (Lumbreras) is a low-cost non-quantitative test, but may provide useful information in low burden areas. We compared the prevalence of intestinal helminth infections assessed by the Kato-Katz and the Lumbreras rapid sedimentation test on 3 stool speci...

Intercomparison of techniques for estimation of sedimentation rate in the Sabah and Sarawak coastal waters

International Nuclear Information System (INIS)

Zal U'yun Wan Mahmood; Zaharudin Ahmad; Abdul Kadir Ishak; Che Abd Rahim Mohamed

2011-01-01

A total of eight sediment cores with 50 cm length were taken in the Sabah and Sarawak coastal waters using a gravity corer in 2004 to estimate sedimentation rates using four mathematical models of CIC, Shukla-CIC, CRS and ADE. The average of sedimentation rate ranged from 0.24 to 0.48 cm year -1 , which is calculated based on the vertical profile of 210 Pbex in sediment core. The finding also showed that the sedimentation rates derived from four models were generally shown in good agreement with similar or comparable value at some stations. However, based on statistical analysis of paired sample t-test indicated that CIC model was the most accurate, reliable and suitable technique to determine the sedimentation rate in the coastal area. (author)

Asymmetric fluxes of water and sediments in a mesotidal mudflat channel

Science.gov (United States)

Mariotti, G.; Fagherazzi, S.

2011-01-01

The hydrodynamics of a small tributary channel and its adjacent mudflat is studied in Willapa Bay, Washington State, USA. Velocity profiles and water levels are simultaneously measured at different locations in the channel and on the mudflat for two weeks. The above tidal flat and channel hydrodynamics differ remarkably during the tidal cycle. When the water surface level is above the tidal flat elevation, the channel is inactive. At this stage, the above tidal flat flow is predominantly aligned along the Bay axis, oscillating with the tide as a standing wave with peak velocities up to 0.3 m/s. When the mudflat becomes emergent, the flow concentrates in the channel. During this stage, current velocities up to 1 m/s are measured during ebb; and up to 0.6 m/s during flood. Standard equations for open-channel flow are utilized to study the channel hydrodynamics. From the continuity equation, a lateral inflow is predicted during ebb, which likely originates from the drainage of the mudflat through the lateral runnels. Both advective acceleration and lateral discharge terms, estimated directly from the velocity profiles, play a significant role in the momentum equation. The computed drag coefficient for bottom friction is small, due to an absence of vegetation and bottom bedforms in the channel. Sediment fluxes are calculated by combining flow and suspended sediment concentration estimated using the acoustic backscatter signal of the instruments. A net export of the sediment from the channel is found during ebb, which is not balanced by the sediment import during flood. When the mudflat is submerged, ebb-flood asymmetries in suspended sediment concentration are present, leading to a net sediment flux toward the inner part of the Willapa Bay. Finally, a residual flow is detected inside the channel at high slack water, probably associated with the thermohaline circulation.

The influence of environmental conditions on lead transfer from spent gunshot to sediments and water: Other routes for Pb poisoning.

Science.gov (United States)

Binkowski, Łukasz J

2017-11-01

Lead (Pb) from spent gunshot and fishing sinkers is recognized as the main source of Pb poisoning among waterfowl. It is also suspected to directly pollute water and sediments, but no appropriate, comprehensive evaluation of this issue has so far been carried out. An experiment on Pb pellets in microcosms (n = 160) with two sediment types (mud and gravel), three water pH values (4, 7 and 9) and two wind levels (wind and windless simulation) was therefore run. Substantial differences in Pb transfer (measured with ICP-OES) between sediment types and pH levels of water were observed. Simulated wind conditions were a significant factor only for some variables and circumstances. The strongest Pb deposit to water and sediments occurred in mud microcosms with water of pH value of 4. Median pellet erosion during the experiment differed little between sediment types. The experiment revealed that Pb transfer from spent gunshot to the environment occurs only in specific environmental conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

SedFoam-2.0: a 3-D two-phase flow numerical model for sediment transport

Directory of Open Access Journals (Sweden)

J. Chauchat

2017-11-01

Full Text Available In this paper, a three-dimensional two-phase flow solver, SedFoam-2.0, is presented for sediment transport applications. The solver is extended from twoPhaseEulerFoam available in the 2.1.0 release of the open-source CFD (computational fluid dynamics toolbox OpenFOAM. In this approach the sediment phase is modeled as a continuum, and constitutive laws have to be prescribed for the sediment stresses. In the proposed solver, two different intergranular stress models are implemented: the kinetic theory of granular flows and the dense granular flow rheology μ(I. For the fluid stress, laminar or turbulent flow regimes can be simulated and three different turbulence models are available for sediment transport: a simple mixing length model (one-dimensional configuration only, a k − ε, and a k − ω model. The numerical implementation is demonstrated on four test cases: sedimentation of suspended particles, laminar bed load, sheet flow, and scour at an apron. These test cases illustrate the capabilities of SedFoam-2.0 to deal with complex turbulent sediment transport problems with different combinations of intergranular stress and turbulence models.

SedFoam-2.0: a 3-D two-phase flow numerical model for sediment transport

Science.gov (United States)

Chauchat, Julien; Cheng, Zhen; Nagel, Tim; Bonamy, Cyrille; Hsu, Tian-Jian

2017-11-01

In this paper, a three-dimensional two-phase flow solver, SedFoam-2.0, is presented for sediment transport applications. The solver is extended from twoPhaseEulerFoam available in the 2.1.0 release of the open-source CFD (computational fluid dynamics) toolbox OpenFOAM. In this approach the sediment phase is modeled as a continuum, and constitutive laws have to be prescribed for the sediment stresses. In the proposed solver, two different intergranular stress models are implemented: the kinetic theory of granular flows and the dense granular flow rheology μ(I). For the fluid stress, laminar or turbulent flow regimes can be simulated and three different turbulence models are available for sediment transport: a simple mixing length model (one-dimensional configuration only), a k - ɛ, and a k - ω model. The numerical implementation is demonstrated on four test cases: sedimentation of suspended particles, laminar bed load, sheet flow, and scour at an apron. These test cases illustrate the capabilities of SedFoam-2.0 to deal with complex turbulent sediment transport problems with different combinations of intergranular stress and turbulence models.

Water and suspended sediment division at a stratified tidal junction

NARCIS (Netherlands)

Buschman, F.A.; Vegt, van der M.; Hoitink, A.J.F.; Hoekstra, P.

2013-01-01

[1] Tidal junctions play a crucial role in the transport of water, salt, and sediment through a delta distributary network. Water, salt and sediment are exchanged at tidal junctions, thereby influencing the transports in the connecting branches and the overall dynamics of the system. This paper

Calibration and application of an automated seepage meter for monitoring water flow across the sediment-water interface.

Science.gov (United States)

Zhu, Tengyi; Fu, Dafang; Jenkinson, Byron; Jafvert, Chad T

2015-04-01

The advective flow of sediment pore water is an important parameter for understanding natural geochemical processes within lake, river, wetland, and marine sediments and also for properly designing permeable remedial sediment caps placed over contaminated sediments. Automated heat pulse seepage meters can be used to measure the vertical component of sediment pore water flow (i.e., vertical Darcy velocity); however, little information on meter calibration as a function of ambient water temperature exists in the literature. As a result, a method with associated equations for calibrating a heat pulse seepage meter as a function of ambient water temperature is fully described in this paper. Results of meter calibration over the temperature range 7.5 to 21.2 °C indicate that errors in accuracy are significant if proper temperature-dependence calibration is not performed. The proposed calibration method allows for temperature corrections to be made automatically in the field at any ambient water temperature. The significance of these corrections is discussed.

Responses of plant water use to a severe summer drought for two subtropical tree species in the central southern China

Directory of Open Access Journals (Sweden)

Zidong Luo

2016-12-01

New hydrological insights: The results show that a decrease in water use during the drought for both two species is closely associated with an increase in vapor pressure deficit and a decrease in stem water potential. The two species appear to be anisohydric, but to a different degree in response to the drought. The hydrodynamic water potential gradient (Δψ maintains relatively constant with an average value of 0.59 MPa for C. camphora, and 1.59 MPa for O. fragrans. O. fragrans is less sensitive to drought than C. camphora, while C. camphora shows an effective survival mechanism via leaf shedding and dieback of shoots.

Evaluation of surficial sediment toxicity and sediment physico-chemical characteristics of representative sites in the Lagoon of Venice (Italy)

Science.gov (United States)

Losso, C.; Arizzi Novelli, A.; Picone, M.; Marchetto, D.; Pessa, G.; Molinaroli, E.; Ghetti, P. F.; Volpi Ghirardini, A.

2004-11-01

Toxic hazard in sites with varying types and levels of contamination in the Lagoon of Venice was estimated by means of toxicity bioassays based on the early life-stages of the autochthonous sea urchin Paracentrotus lividus. Elutriate was chosen as the test matrix, due to its ability to highlight potential toxic effects towards sensitive biological components of the water column caused by sediment resuspension phenomena affecting the Lagoon. Surficial sediments (core-top 5 cm deep), directly influenced by resuspension/redeposition processes, and core sediments (core 20 cm deep), recording time-mediated contamination, were sampled in some sites located in the lagoonal area most greatly influenced by anthropogenic activities. Particle size, organic matter and water content were also analysed. In two sites, the results of physical parameters showed that the core-top sediments were coarser than the 20-cm core sediments. Sperm cell toxicity test results showed the negligible acute toxicity of elutriates from all investigated sites. The embryo toxicity test demonstrated a short-term chronic toxicity gradient for elutriates from the 20-cm core sediments, in general agreement both with the expected contamination gradient and with results of the Microtox® solid-phase test. Elutriates of the core-top 5-cm sediments revealed a totally inverted gradient, in comparison with that for the 20-cm core sediments, and the presence of a "hot spot" of contamination in the site chosen as a possible reference. Investigations on ammonia and sulphides as possible confounding factors excluded their contribution to this "hot spot". Integrated physico-chemical and toxicity results on sediments at various depths demonstrated the presence of disturbed sediments in the central basin of the Lagoon of Venice.

The rate of 45Ca uptake by two corals species at waters of Burung island, Bangka-Belitung province

International Nuclear Information System (INIS)

Zulkifli Dahlan; Gusti Diansyah; T Zia Ulqodry; Ania Citraresmini

2010-01-01

Coral reefs transplantation is the most technique used for coral reefs rehabilitation, at the present. Recently the 45 Ca technique has been using for determining growth appearances in corals because of its ability to calculate the calcification process. For this reason, the study on the rate of 45 Ca uptake by natural corals Acropora Formosa and Acropora nobilis was carried out between June and December 2009 at the waters of Burung Island, Bangka-Belitung Province. The coral fragments of about 5 cm were harvested and put into a PVC container filled with 2 liters of fresh sea water, then incubated with 45 CaCl 2 solutions with an activity of 11.04 μCi/ml for 8 hour under fluorescent light. After the incubation, the “labeled” coral fragments were transplanted to where they have been taken from, and after such period will be re-harvested to determine their 45 Ca uptake content. The results showed that the 45 Ca technique was a reliable method to calculate the rate 45 Ca uptake by coral fragments, which were studied in different depths and time periods of light exposure. There was a significant difference in the 45 Ca uptake by the two different coral species. A. Formosa up took more 45 Ca than A. nobilis did. The highest 45 Ca uptake was shown by A. Formosa at 5 m. This was true for all the lengths of time to light exposure (1, 3, 5 and 7 hours). Different pattern of 45 Ca uptake showed by A. nobilisat 10 m depth, where it could be recognized that after a drop of 45 Ca the uptake increase continuously until the end of the light exposure (7 hours). The difference in 45 Ca uptake between the coral fragments is assumed to be influence by light and the algae species living symbiotically with the coral species that will further influence the CO 2 -fixation. This process will influence the calcification process, which is expressed in 45 Ca uptake. Further studies should be carried out to exactly gathered data of all the factors which could influence the calcification

Water and suspended sediment dynamics in the Sungai Selangor estuary

International Nuclear Information System (INIS)

Abdul Kadir Ishak; Kamarudin Samuding; Nazrul Hizam Yusoff

2000-01-01

Observations of salinity, temperature, suspended sediment concentration (SSC) and tidal current velocity were made in the lower and along the longitudinal axis sungai Selangor estuary over near-spring cycles. The variations of these parameters at the measurement stations and along the channel are presented to illustrate the water and sediment dynamics in the estuary. The results shows that the Sungai Selangor estuary changes from a partially-mixed type during neaps to a well-mixed one during springs. promoted by stronger tidal energy during the higher tidal ranges. The strong neap density stratification is also promoted by the high river discharges during the measurement period maximum concentration of suspended sediment 2000 mg,'/) occurs during maximum current velocities both during flood and ebb. The maximum salinity was achieved during high water slack but the salt water was totally flushed out of estuary during low water springs. The longitudinal axis measurement indicates that a partially-developed zone of turbidity maximum with a sediment concentration over 1000 mg/l was observed at the limit of salt water intrusion in salinity range less than 1 ppt. Tidal pumping as oppose to the estuarine circulation is the more dominant factor in the maximum formation as the salt water is totally excluded at low water. (author)

Study of polluted water mixing on sediment of Lahore canal

International Nuclear Information System (INIS)

Asim, M.

2016-01-01

People living in societies along the canals which pass through the urban areas, are adding domestic and industrial waste water and wastes into them like Lahore canal. This untreated industrial and municipal waste and contaminated water may become a risk to irrigation water quality and sediment moving in it in the form of suspended load. The results disclose that as suspended sediment concentration increases the pH value drops. Consequently it can be established from results that they are inversely related to each other but this behaviour is generally due to effect of rain water runoff. The suspended sediment content was at its highest during monsoon season. Similarly pH values varied considerably from limit of 6.5-8.4. Other water quality chemical parameters did not stray from their recommended limits. The dumping of waste water from pipes did not have any major effect on the water quality of the canal due to its less percentage to the total canal discharge. (author)

Essential and non-essential element concentrations in two sleeper shark species collected in arctic waters

Energy Technology Data Exchange (ETDEWEB)

McMeans, Bailey C. [Great Lakes Institute for Environmental Research, University of Windsor, 401 Sunset Avenue, Windsor, ON, N9B 3P4 (Canada); Borga, Katrine [Norwegian Institute for Water Research, P.O. Box 173, Kjelsas, N-0411 Oslo (Norway); Bechtol, William R. [Alaska Department of Fish and Game, Division of Commercial Fisheries, Anchorage, AK 99518-1599 (United States); Higginbotham, David [Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA 30602-2152 (United States); Fisk, Aaron T. [Great Lakes Institute for Environmental Research, University of Windsor, 401 Sunset Avenue, Windsor, ON, N9B 3P4 (Canada)]. E-mail: afisk@uwindsor.ca

2007-07-15

A number of elements/metals have increased in arctic biota and are of concern due to their potential toxicity. Most studies on elements in the Arctic have focused on marine mammals and seabirds, but concentrations in the Greenland shark (Somniosus microcephalus) and Pacific sleeper shark (Somniosus pacificus), the only two shark species known to regularly inhabit arctic waters, have never been reported. To address this data gap, concentrations and patterns of 25 elements were analyzed in liver of Greenland sharks collected about Cumberland Sound (n = 24) and Pacific sleeper sharks collected about Prince William Sound (n = 14). Several non-essential elements differed between species/locations, which could suggest geographical exposure differences or ecological (e.g., diet) differences between the species. Certain essential elements also differed between the two sleeper sharks, which may indicate different physiological requirements between these closely related shark species, although information on such relationships are lacking for sharks and fish. - Patterns of essential and non-essential elements provide insight into sleeper shark biology and physiology.

Essential and non-essential element concentrations in two sleeper shark species collected in arctic waters

International Nuclear Information System (INIS)

McMeans, Bailey C.; Borga, Katrine; Bechtol, William R.; Higginbotham, David; Fisk, Aaron T.

2007-01-01

A number of elements/metals have increased in arctic biota and are of concern due to their potential toxicity. Most studies on elements in the Arctic have focused on marine mammals and seabirds, but concentrations in the Greenland shark (Somniosus microcephalus) and Pacific sleeper shark (Somniosus pacificus), the only two shark species known to regularly inhabit arctic waters, have never been reported. To address this data gap, concentrations and patterns of 25 elements were analyzed in liver of Greenland sharks collected about Cumberland Sound (n = 24) and Pacific sleeper sharks collected about Prince William Sound (n = 14). Several non-essential elements differed between species/locations, which could suggest geographical exposure differences or ecological (e.g., diet) differences between the species. Certain essential elements also differed between the two sleeper sharks, which may indicate different physiological requirements between these closely related shark species, although information on such relationships are lacking for sharks and fish. - Patterns of essential and non-essential elements provide insight into sleeper shark biology and physiology

Transport of Water, Carbon, and Sediment Through the Yukon River Basin

Science.gov (United States)

Brabets, Timothy P.; Schuster, Paul F.

2008-01-01

during peak- and low-flow conditions as part of synoptic sampling campaigns. Although the synoptic data do not provide a complete picture of water quality of a particular river through the year, the data do provide a snapshot of water-quality conditions at a particular time of year. Two constituents of interest are suspended sediment and dissolved organic carbon (DOC). Suspended sediment is important because elevated concentrations can adversely affect aquatic life by obstructing fish gills, covering fish spawning sites, and altering habitat of benthic organisms. Metals and organic contaminants also tend to adsorb onto fine-grained sediment. Permafrost thawing has major implications for the carbon cycle. It is critical to understand the processes related to the transport of DOC to surface waters and how long-term climatic changes may alter these processes (Schuster and others, 2004).

Can the hemoglobin characteristics of vesicomyid clam species influence their distribution in deep-sea sulfide-rich sediments? A case study in the Angola Basin

Science.gov (United States)

Decker, C.; Zorn, N.; Le Bruchec, J.; Caprais, J. C.; Potier, N.; Leize-Wagner, E.; Lallier, F. H.; Olu, K.; Andersen, A. C.

2017-08-01

Vesicomyids live in endosymbiosis with sulfur-oxidizing bacteria and therefore need hydrogen sulfide to survive. They can nevertheless live in a wide range of sulfide and oxygen levels and depths, which may explain the exceptional diversity of this clam family in deep-sea habitats. In the Gulf of Guinea, nine species of vesicomyid clams are known to live in cold-seep areas with pockmarks from 600 to 3200 m deep, as well as in the organic-rich sediments of the Congo deep-sea fan at 5000 m deep. Our previous study showed that two species living in a giant pockmark have different oxygen carriers, suggesting different adaptations to hypoxia. Here, we studied the hemoglobin structure and oxygen affinity in three other species, Calyptogena valdiviae, Elenaconcha guiness and Abyssogena southwardae to determine whether the characteristics of their oxygen carriers contribute to their distribution in sulfide-rich sediments at a regional scale. Documenting pairwise species associations in various proportions, we give a semi-quantitative account of their local distribution and oxygen and sulfide measurements at seven sites. Mass spectrometry showed that each vesicomyid species has four intracellular monomeric hemoglobin molecules of 15-16 kDa, all differing in their molecular mass. As expected, the monomers showed no cooperativity in oxygen binding. Their oxygen affinities were very high (below 1 Torr), but differed significantly. C. valdiviae had the highest affinity and was dominant in the Harp pockmark, the site with the lowest oxygen content (half the value of fully oxygenated water). A. southwardae dominated in the Congo Lobe area, the site with the deepest sulfides. We discuss how hemoglobin may favor an active, vertical distribution of vesicomyids in sulfide-rich sediments.

The effect of lake sediment on the hatching success of Daphnia ephippial eggs

Directory of Open Access Journals (Sweden)

Jacek Radzikowski

2016-07-01

Full Text Available A large proportion of lake-Daphnia ephippia which are shed by females in the water column sink to the bottom, where they form an assemblage of dormant stages known as an egg bank. Although the quantity of zooplankton eggs in such assemblages may exceed tens of thousands per square meter, the annual hatch from this bank is usually extremely low (from zero to a few dozens animals per square meter per year. This low-hatching phenomenon may be caused by isolation from hatching stimuli by water or sediment layers, a mechanical barrier formed by sediment that does not allow hatchlings to reach the water, or by a bet-hedging strategy of the resting eggs. The aim of our study was to determine the extent to which coverage by lake sediment may affect the hatching of Daphnia dormant eggs. The ephippia of lake-Daphnia (longispina species complex, covered by sterilized lake sediment of different thicknesses (0, 0.25, 0.5, 1, 2 and 4 cm; 4 replicates per treatment, were incubated for 8 weeks in lab controlled conditions. The results indicate that even the thinnest tested layer (0.25 cm may completely inhibit hatching of ephippial eggs. A few Daphnia neonates were observed in two (of five sediment treatments, while dozens of animals hatched in the control one. In the second experiment we determined that the sediment sterilization process did not affect the hatching proportion of ephippial eggs (when compared to the treatment with unsterilized sediments. We hypothesize that the observed inhibition of Daphnia hatching in the main experiment, which may cause a serious problem for Cladoceran populations in lakes where no sediment mixing occurs, may be caused by low light intensity, anoxic conditions or a physical barrier created by the sediment.

Sediment filtration can reduce the N load of the waste water discharge - a full-scale lake experiment

Science.gov (United States)

Aalto, Sanni L.; Saarenheimo, Jatta; Karvinen, Anu; Rissanen, Antti J.; Ropponen, Janne; Juntunen, Janne; Tiirola, Marja

2016-04-01

European commission has obliged Baltic states to reduce nitrate load, which requires high investments on the nitrate removal processes and may increase emissions of greenhouse gases, e.g. N2O, in the waste water treatment plants. We used ecosystem-scale experimental approach to test a novel sediment filtration method for economical waste water N removal in Lake Keurusselkä, Finland between 2014 and 2015. By spatially optimizing the waste water discharge, the contact area and time of nitrified waste water with the reducing microbes of the sediment was increased. This was expected to enhance microbial-driven N transformation and to alter microbial community composition. We utilized 15N isotope pairing technique to follow changes in the actual and potential denitrification rates, nitrous oxide formation and dissimilatory nitrate reduction to ammonium (DNRA) in the lake sediments receiving nitrate-rich waste water input and in the control site. In addition, we investigated the connections between observed process rates and microbial community composition and functioning by using next generation sequencing and quantitative PCR. Furthermore, we estimated the effect of sediment filtration method on waste water contact time with sediment using the 3D hydrodynamic model. We sampled one year before the full-scale experiment and observed strong seasonal patterns in the process rates, which reflects the seasonal variation in the temperature-related mixing patterns of the waste water within the lake. During the experiment, we found that spatial optimization enhanced both actual and potential denitrification rates of the sediment. Furthermore, it did not significantly promote N2O emissions, or N retention through DNRA. Overall, our results indicate that sediment filtration can be utilized as a supplemental or even alternative method for the waste water N removal.

Long-Term Impact of Sediment Deposition and Erosion on Water Surface Profiles in the Ner River

Directory of Open Access Journals (Sweden)

Tomasz Dysarz

2017-02-01

Full Text Available The purpose of the paper is to test forecasting of the sediment transport process, taking into account two main uncertainties involved in sediment transport modeling. These are: the lack of knowledge regarding future flows, and the uncertainty with respect to which sediment transport formula should be chosen for simulations. The river reach chosen for study is the outlet part of the Ner River, located in the central part of Poland. The main characteristic of the river is the presence of an intensive morphodynamic process, increasing flooding frequency. The approach proposed here is based on simulations with a sediment-routing model and assessment of the hydraulic condition changes on the basis of hydrodynamic calculations for the chosen characteristic flows. The data used include Digital Terrain Models (DTMs, cross-section measurements, and hydrological observations from the Dabie gauge station. The sediment and hydrodynamic calculations are performed using program HEC-RAS 5.0. Twenty inflow scenarios are of a 10-year duration and are composed on the basis of historical data. Meyer-Peter and Müller and Engelund-Hansen formulae are applied for the calculation of sediment transport intensity. The methodology presented here seems to be a good tool for the prediction of long-term impacts on water surface profiles caused by sediment deposition and erosion.

Testing deep-sea biodiversity paradigms on abyssal nematode genera and Acantholaimus species

Science.gov (United States)

Lins, Lidia; da Silva, Maria Cristina; Neres, Patrícia; Esteves, André Morgado; Vanreusel, Ann

2018-02-01

Biodiversity patterns in the deep sea have been extensively studied in the last decades. In this study, we investigated whether reputable concepts in deep-sea ecology also explain diversity and distribution patterns of nematode genera and species in the abyss. Among them, three paradigms were tackled: (1) the deep sea is a highly diverse environment at a local scale, while on a regional and even larger geographical scale, species and genus turnover is limited; (2) the biodiversity of deep-sea nematode communities changes with the nature and amount of organic matter input from the surface; and (3) patch-mosaic dynamics of the deep-sea environment drive local diversity. To test these hypotheses, diversity and density of nematode assemblages and of species of the genus Acantholaimus were studied along two abyssal E-W transects. These two transects were situated in the Southern Ocean ( 50°S) and the North Atlantic ( 10°N). Four different hierarchical scales were used to compare biodiversity: at the scale of cores, between stations from the same region, and between regions. Results revealed that the deep sea harbours a high diversity at a local scale (alpha diversity), but that turnover can be shaped by different environmental drivers. Therefore, these results question the second part of the paradigm about limited species turnover in the deep sea. Higher surface primary productivity was correlated with greater nematode densities, whereas diversity responses to the augmentation of surface productivity showed no trend. Areas subjected to a constant and low food input revealed similar nematode communities to other oligotrophic abyssal areas, while stations under high productivity were characterized by different dominant genera and Acantholaimus species, and by a generally low local diversity. Our results corroborate the species-energy hypothesis, where productivity can set a limit to the richness of an ecosystem. Finally, we observed no correlation between sediment

The sequence of sediment behaviour during wave-induced liquefaction

DEFF Research Database (Denmark)

Sumer, B. Mutlu; Hatipoglu, Figen; Fredsøe, Jørgen

2006-01-01

to be in agreement with recent centrifuge wave-tank experiments. As for the final stage of the sequence of processes (formation of ripples), the ripple steepness (normalized with the angle of repose) for sediment with liquefaction history is found to be the same as that in sediment with no liquefaction history.......This paper presents the results of an experimental investigation of the complete sequence of sediment behaviour beneath progressive waves. The sediment was silty with d(50) = 0.060 mm. Two kinds of measurements were carried out: pore-water pressure measurements (across the sediment depth...... of liquefaction and compaction fronts in the sediment and (iii) the characteristics of the orbital motion of the liquefied sediment including the motion of the interface between the water body and the sediment. The ranges of the various quantities in the tests were: wave height, H = 9-17 cm, wave period, T = 1...

Cytogenotoxicity screening of source water, wastewater and treated water of drinking water treatment plants using two in vivo test systems: Allium cepa root based and Nile tilapia erythrocyte based tests.

Science.gov (United States)

Hemachandra, Chamini K; Pathiratne, Asoka

2017-01-01

Biological effect directed in vivo tests with model organisms are useful in assessing potential health risks associated with chemical contaminations in surface waters. This study examined the applicability of two in vivo test systems viz. plant, Allium cepa root based tests and fish, Oreochromis niloticus erythrocyte based tests for screening cytogenotoxic potential of raw source water, water treatment waste (effluents) and treated water of drinking water treatment plants (DWTPs) using two DWTPs associated with a major river in Sri Lanka. Measured physico-chemical parameters of the raw water, effluents and treated water samples complied with the respective Sri Lankan standards. In the in vivo tests, raw water induced statistically significant root growth retardation, mitodepression and chromosomal abnormalities in the root meristem of the plant and micronuclei/nuclear buds evolution and genetic damage (as reflected by comet scores) in the erythrocytes of the fish compared to the aged tap water controls signifying greater genotoxicity of the source water especially in the dry period. The effluents provoked relatively high cytogenotoxic effects on both test systems but the toxicity in most cases was considerably reduced to the raw water level with the effluent dilution (1:8). In vivo tests indicated reduction of cytogenotoxic potential in the tested drinking water samples. The results support the potential applications of practically feasible in vivo biological test systems such as A. cepa root based tests and the fish erythrocyte based tests as complementary tools for screening cytogenotoxicity potential of the source water and water treatment waste reaching downstream of aquatic ecosystems and for evaluating cytogenotoxicity eliminating efficacy of the DWTPs in different seasons in view of human and ecological safety. Copyright © 2016 Elsevier Ltd. All rights reserved.

Sediment distribution and composition on the shallow water ...

African Journals Online (AJOL)

Sediments of the shallow water carbonate basin in Zanzibar channel were investigated for composition and grain size distribution. The surface sediment composition was dominated by carbonate sands (with CaCO3 > 30%), except in the area adjacent to mainland coastline and a thin lobe which projects from Ruvu River to ...

Effects of wind-wave disturbances on adsorption and desorption of tetracycline and sulfadimidine in water-sediment systems.

Science.gov (United States)

Liao, Qianjiahua; Huang, Zheng; Li, Shu; Wang, Yi; Liu, Yuqing; Luo, Ran; Shang, Jingge

2018-05-28

Wind-wave disturbances frequently disperse sediment particles into overlying water, which facilitates the adsorption and desorption of contaminants in aquatic ecosystems. Tetracycline (TC) and sulfadimidine (SM2) are common antibiotics that are frequently found in aquatic environments. This study utilized microcosms, comprising sediment and water from Lake Taihu, China, to examine the adsorption and desorption of TC and SM2 under different wind-wave disturbances in a shallow lake environment. The adsorption experiments were conducted with three different concentrations (1, 5, 10 mg/L) of TC and SM2 in the overlying water, and two different (background and strong) wind-wave conditions for 72 h. Subsequently, four microcosms were employed in a 12-h desorption study. Analysis of adsorption progress showed that TC concentration in the overlying water decreased quickly, while SM2 remained almost constant. In the desorption experiments, SM2 released to the overlying water was an order of magnitude greater than TC. These results indicate that sediment particles strongly adsorb TC but weakly adsorb SM2. Compared to background conditions, the strong wind-wave conditions resulted in higher concentrations of TC and SM2 in sediment and facilitated their migration to deeper sediment during adsorption, correspondingly promoting greater release of TC and SM2 from sediment particles into the overlying water during desorption.

Assessing sediment contamination using six toxicity assays

Directory of Open Access Journals (Sweden)

Allen G. BURTON Jr.

2001-08-01

Full Text Available An evaluation of sediment toxicity at Lake Orta, Italy was conducted to compare a toxicity test battery of 6 assays and to evaluate the extent of sediment contamination at various sediment depths. Lake Orta received excessive loadings of copper and ammonia during the 1900’s until a large remediation effort was conducted in 1989-90 using lime addition. Since that time, the lake has shown signs of a steady recovery of biological communities. The study results showed acute toxicity still exists in sediments at a depth of 5 cm and greater. Assays that detected the highest levels of toxicity were two whole sediment exposures (7 d using Hyalella azteca and Ceriodaphnia dubia. The MicrotoxR assay using pore water was the third most sensitive assay. The Thamnotox, Rototox, Microtox solid phase, and Seed Germination-Root Elongation (pore and solid phase assays showed occasional to no toxicity. Based on similarity of responses and assay sensitivity, the two most useful assays were the C. dubia (or H. azteca and Microtox pore water. These assays were effective at describing sediment toxicity in a weight-of-evidence approach.

Winter evolution of DMS and DMSP in Venice lagoon water and sediment.

Science.gov (United States)

Gambaro, Andrea; Moret, Ivo; Piazza, Rossano; Da Rin, Eleonora; Turetta, Clara; Cescon, Paolo

2002-03-01

The evolution of dimethylsulphide (DMS) and dimethylsulphoniopropionate (DMSP) concentrations in the water and sediment of the Venice lagoon were studied together with the concentration of chlorophyll a, temperature and the composition and density of phytoplankton to understand the role of the sediment as a source of DMS during the winter period. The temporal trend of water DMS concentration in this period showed a maximum concentration in February (75.7 nmol S l-1) related to low DMSP and chlorophyll a concentrations but to high phytoplanktonic abundance. The DMS and DMSP concentrations were greater in the sediment than in the water. The temporal trend of DMS concentration in sediment showed a maximum in February (1155 nmol S l-1) related to the maximum of DMS concentration in surface water. These observations suggested that in the winter period DMS could be produced by the conversion of the DMSP present in the bulk water but principally by that present in the sediment (microbiological degradation of DMSP or other sulphur-containing compounds) that subsequently diffuse in water.

Effects of sediment organic matter quality on bioaccumulation, degradation, and distribution of pyrene in two macrofaunal species and their surrounding sediment

DEFF Research Database (Denmark)

Granberg, M. E.; Selck, H.

2007-01-01

Sediment dwelling macrofauna (infauna) are important vectors for the transfer of sediment-associated contaminants to higher trophic levels. Sedimenting organic matter constitutes an important food source for all benthic organisms and changes seasonally in terms of quantity and quality. Sediment...... organic matter (SOM) quality affects organism activity and feeding behaviour, and is therefore also likely to affect contaminant fate in benthic systems. We investigated the impact of SOM quality (enrichment with either labile Tetraselmis sp. or refractory lignin) on the accumulation and metabolism...... imply that bioaccumulation and trophic transfer of sediment-associated PAH should increase following fresh organic matter input, e.g. after sedimentation of phytoplankton blooms. We stress the importance of considering behavioural characteristics of infauna and the trophic situation of the system when...

Chloride, bromide and iodide distributions in Loch Lomond sediment interstitial water

International Nuclear Information System (INIS)

MacKenzie, A.B.; Shimmield, T.M.; Scott, R.D.; Davidson, C.M.; Hooker, P.J.

1991-01-01

The post glacial sediments of Loch Lomond contain a well defined band of marine deposited material which is overlain and underlain by freshwater deposited sediment. The chronology of the sedimentary sequence has been well established by radiocarbon dating and, in the southern basin of the Loch, the marine sediment band is of the order of 1 m thick and typically occurs at a depth of about 3 to 4 m beneath the sediment surface. Previous work has established that the marine deposited sediment contains enhanced concentrations of iodine and bromine relative to the contiguous freshwater sediments and that dissolution of halogen elements from the marine sediments generates a concentration gradient, with consequent diffusive transport, of these elements in the sediment interstitial water. This environment is thus highly suitable for investigation of the rate of transport of halogen elements through the sediment a topic of direct relevance to radioactive waste disposal in the context of far field migration of 129 I. Previous studies resulted in successful modelling of the diffusive transport of bromine in the interstitial water of the sediment on the basis of the observed concentration profile for total bromine in the water. This work was, however, of restricted value since (1) speciation was not determined (2) archived sediment was used and (3) samples were processed and analyzed under ambient laboratory conditions. The objective of the work described in this report was to collect a new core of Loch Lomond sediment and to carry out appropriate analyses to overcome the above limitations

Statistical modelling of variability in sediment-water nutrient and oxygen fluxes

Science.gov (United States)

Serpetti, Natalia; Witte, Ursula; Heath, Michael

2016-06-01

Organic detritus entering, or produced, in the marine environment is re-mineralised to inorganic nutrient in the seafloor sediments. The flux of dissolved inorganic nutrient between the sediment and overlying water column is a key process in the marine ecosystem, which binds the biogeochemical sub-system to the living food web. These fluxes are potentially affected by a wide range of physical and biological factors and disentangling these is a significant challenge. Here we develop a set of General Additive Models (GAM) of nitrate, nitrite, ammonia, phosphate, silicate and oxygen fluxes, based on a year-long campaign of field measurements off the north-east coast of Scotland. We show that sediment grain size, turbidity due to sediment re-suspension, temperature, and biogenic matter content were the key factors affecting oxygen consumption, ammonia and silicate fluxes. However, phosphate fluxes were only related to suspended sediment concentrations, whilst nitrate fluxes showed no clear relationship to any of the expected drivers of change, probably due to the effects of denitrification. Our analyses show that the stoichiometry of nutrient regeneration in the ecosystem is not necessarily constant and may be affected by combinations of processes. We anticipate that our statistical modelling results will form the basis for testing the functionality of process-based mathematical models of whole-sediment biogeochemistry.

Heavy metal concentrations and toxicity in water and sediment from stormwater ponds and sedimentation tanks.

Science.gov (United States)

Karlsson, Kristin; Viklander, Maria; Scholes, Lian; Revitt, Mike

2010-06-15

Sedimentation is a widely used technique in structural best management practices to remove pollutants from stormwater. However, concerns have been expressed about the environmental impacts that may be exerted by the trapped pollutants. This study has concentrated on stormwater ponds and sedimentation tanks and reports on the accumulated metal concentrations (Cd, Cr, Ni, Pb, and Zn) and the associated toxicity to the bacteria Vibrio fischeri. The metal concentrations are compared with guidelines and the toxicity results are assessed in relation to samples for which metal concentrations either exceed or conform to these values. The water phase metal concentrations were highest in the ponds whereas the sedimentation tanks exhibited a distinct decrease towards the outlet. However, none of the water samples demonstrated toxicity even though the concentrations of Cu, Pb, and Zn exceeded the threshold values for the compared guidelines. The facilities with higher traffic intensities had elevated sediment concentrations of Cr, Cu, Ni, and Zn which increased towards the outlet for the sedimentation tanks in agreement with the highest percentage of fine particles. The sediments in both treatment facilities exhibited the expected toxic responses in line with their affinity for heavy metals but the role of organic carbon content is highlighted. Copyright 2010 Elsevier B.V. All rights reserved.

Salmonella rarely detected in Mississippi coastal waters and sediment.

Science.gov (United States)

Carr, M R; Wang, S Y; McLean, T I; Flood, C J; Ellender, R D

2010-12-01

Standards for the rapid detection of individual pathogens from environmental samples have not been developed, but in their absence, the use of molecular-based detection methods coupled with traditional microbiology techniques allows for rapid and accurate pathogen detection from environmental waters and sediment. The aim of this research was to combine the use of enrichment with PCR for detection of Salmonella in Mississippi coastal waters and sediment and observe if that presence correlated with levels of enterococci and climatological variables. Salmonella were primarily found in samples that underwent nutrient enrichment and were present more frequently in freshwater than marine waters. Salmonella were detected infrequently in marine and freshwater sediments. There was a significant positive correlation between the presence of detectable Salmonella and the average enterococcal count. An inverse relationship, however, was observed between the frequency of detection and the levels of salinity, turbidity and sunlight exposure. Results from this study indicated the presence of Salmonella in Mississippi coastal waters, and sediments are very low with significant differences between freshwater and marine environments. Using pathogenic and novel nonpathogenic molecular markers, Salmonella do not appear to be a significant pathogenic genus along the Mississippi Coast. © 2010 The Authors. Journal of Applied Microbiology © 2010 The Society for Applied Microbiology.

Viable Species of Flamella (Amoebozoa: Variosea) Isolated from Ancient Arctic Permafrost Sediments.

Science.gov (United States)

Shmakova, Lyubov; Bondarenko, Natalya; Smirnov, Alexey

2016-02-01

Six viable strains of amoebae belonging to the genus Flamella (Amoebozoa, Variosea) were isolated from permafrost sediments sampled in the Russian Arctic region. Two of them are from late Pleistocene permafrost in North-East Siberia, and four--from Holocene and late Pleistocene in North-West Siberia. Light- and electron-microscopic study and molecular phylogeny show that these isolates represent two new species belonging to the genus Flamella. Both species are cyst-forming. This is a remarkable case of high resistance of protozoan cysts, allowing them to survive and recover an amoebae population after a very long, geologically significant period of rest; a "snapshot" of evolution in time. This study directly shows for the first time that amoeba cysts can be conserved not only for years and decades but for many thousand years and then recover, contributing to the formation of an active microbial community. We propose to name the new species as Flamella pleistocenica n.sp. and Flamella beringiania n.sp. Phylogenetic analysis shows that the genus Flamella is a robust and potentially species-rich group of Variosea. Copyright © 2015 Elsevier GmbH. All rights reserved.

Experimental and in situ investigations on americium, curium and plutonium behaviour in marine benthic species: transfer from water or sediments

International Nuclear Information System (INIS)

Miramand, P.

1984-06-01

The tranfer of transuranic elements -americium, curium and plutonium- from the sediments containing them to some marine benthic species (endofauna and epifauna) was studied with a twofold approach - laboratory and in-situ investigation. The experimental investigations, divided into three parts, made it possible to specify concentration factors (F.C.), transfer factors (F.T.) and to understand the process involved for 5 benthic species. The result were refined by an in-situ study that brought new data on the marine distribution of the transuranic elements released by the La Hague plant. Finally, the localization of americium and plutonium in the tissues and cells of these species was determined by autoradiography [fr

Water-Sediment Partition of Polycyclic Aromatic Hydrocarbons (PAHs) in Nansi Lake

Science.gov (United States)

Zhang, Guizhai; Diao, Youjiang

2018-06-01

Based on field data of polycyclic aromatic hydrocarbons (PAHs) in water and sediment in Nansi Lake. The concentrations and the partitioning characteristic of PAHs in the water and sediment were studied. The lgKd of high molecular weight PAHs were higher than the low molecular weight PAHs. The most of PAHs Kd values were negligible correlated with TOC, soluble salt, clay and pH of the sediment in Nansi Lake.

Seasonal variation of sediment toxicity in the Rivers Dommel and Elbe

International Nuclear Information System (INIS)

Hsu, P.; Matthaei, A.; Heise, S.; Ahlf, W.

2007-01-01

Contaminated sediment in the river basin has become a source of pollution with increasing importance to the aquatic ecosystem downstream. To monitor the temporal changes of the sediment bound contaminants in the River Elbe and the River Dommel monthly toxicity tests were applied to layered sediment and river water samples over the course of 10 months. There is an indication that contaminated sediments upstream adversely affected sediments downstream, but this process did not cause a continuous increase of sediment toxicity. A clear decrease of toxic effects in water and upper layer sediment was observed at the River Elbe station in spring related to high water discharge and algal blooms. The less obvious variation of sediment toxicity in the River Dommel could be explained by stable hydrological conditions. Future monitoring programmes should promote a more frequent and intensive sampling regime during these particular events for ecotoxicological evaluation. - Significant impacts of hydrological and biological factors on the ecotoxicological quality in two European rivers (Elbe and Dommel)

Extending the analytical window for water-soluble organic matter in sediments by aqueous Soxhlet extraction

Science.gov (United States)

Schmidt, Frauke; Koch, Boris P.; Witt, Matthias; Hinrichs, Kai-Uwe

2014-09-01

Dissolved organic matter (DOM) in marine sediments is a complex mixture of thousands of individual constituents that participate in biogeochemical reactions and serve as substrates for benthic microbes. Knowledge of the molecular composition of DOM is a prerequisite for a comprehensive understanding of the biogeochemical processes in sediments. In this study, interstitial water DOM was extracted with Rhizon samplers from a sediment core from the Black Sea and compared to the corresponding water-extractable organic matter fraction (Soxhlet extraction, which mobilizes labile particulate organic matter and DOM. After solid phase extraction (SPE) of DOM, samples were analyzed for the molecular composition by Fourier Transform Ion-Cyclotron Resonance Mass Spectrometry (FT-ICR MS) with electrospray ionization in negative ion mode. The average SPE extraction yield of the dissolved organic carbon (DOC) in interstitial water was 63%, whereas less than 30% of the DOC in Soxhlet-extracted organic matter was recovered. Nevertheless, Soxhlet extraction yielded up to 4.35% of the total sedimentary organic carbon, which is more than 30-times the organic carbon content of the interstitial water. While interstitial water DOM consisted primarily of carbon-, hydrogen- and oxygen-bearing compounds, Soxhlet extracts yielded more complex FT-ICR mass spectra with more peaks and higher abundances of nitrogen- and sulfur-bearing compounds. The molecular composition of both sample types was affected by the geochemical conditions in the sediment; elevated concentrations of HS- promoted the early diagenetic sulfurization of organic matter. The Soxhlet extracts from shallow sediment contained specific three- and four-nitrogen-bearing molecular formulas that were also detected in bacterial cell extracts and presumably represent proteinaceous molecules. These compounds decreased with increasing sediment depth while one- and two-nitrogen-bearing molecules increased, resulting in a higher

Different techniques of excess 210Pb for sedimentation rate estimation in the Sarawak and Sabah coastal waters

International Nuclear Information System (INIS)

Zal Uyun Wan Mahmood; Zaharudin Ahmad; Abdul Kadir Ishak; Che Abdul Rahim Mohamed

2010-01-01

Sediment core samples were collected at eight stations in the Sarawak and Sabah coastal waters using a gravity box corer to estimate sedimentation rates based on the activity of excess 210 Pb. The sedimentation rates derived from four mathematical models of CIC, Shukla-CIC, CRS and ADE were generally shown in good agreement with similar or comparable value at all stations. However, based on statistical analysis of independent sample t-test indicated that Shukla-CIC model was the most accurate, reliable and suitable technique to determine the sedimentation rate in the study area. (author)

Toxicity of sediment pore water associated with offshore oil and gas platforms in the Gulf of Mexico

International Nuclear Information System (INIS)

Carr, R.S.; Chapman, D.C.

1993-01-01

As a part of a multidisciplinary program to assess the long-term impacts of offshore petroleum production in the Gulf of Mexico, a series of sediment porewater toxicity tests were conducted. Sediments were samples from five petroleum production platforms along five radial transects. Pore water was extracted from the sediment using a pressure extraction device, centrifuged, and frozen for later toxicity testing and chemical analysis. The sea urchin (Arbacia punctulata) embryological development assay and fertilization assay were used to assess porewater toxicity. Significant decreases in normal development of embryos was observed at 14 stations and fertilization was reduced at three stations. All stations with reduced fertilization also showed impaired development in the embryological development assay. All but three toxic sites were within 150 m of the platform. The six most toxic stations were at one platform near the Flower Garden reef, occurring near the platform along three radii; toxicity was always greater at the first site on a radium than at the second. Toxicity is discussed in relation to metal and hydrocarbon concentrations in whole sediment and in pore water

Optimisation of decontamination method and influence of culture media on the recovery of Mycobacterium avium subspecies paratuberculosis from spiked water sediments.

Science.gov (United States)

Aboagye, G; Rowe, M T

2018-07-01

The recovery of Mycobacterium avium subspecies paratuberculosis (Map) from the environment can be a laborious process - owing to Map being fastidious, its low number, and also high numbers of other microbial populations in such settings. Protocols i.e. filtration, decontamination and modified elution were devised to recover Map from spiked water sediments. Three culture media: Herrold's Egg Yolk Media (HEYM), Middlebrook 7H10 (M-7H10) and Bactec 12B were then employed to grow the organism following its elution. In the sterile sediment samples the recovery of Map was significant between the time of exposure for each of HEYM and M-7H10, and insignificant between both media (P < 0.05). However, in the non-sterile sediment samples, the HEYM grew other background microflora including moulds at all the times of exposure whilst 4 h followed by M-7H10 culture yielded Map colonies without any background microflora. Using sterile samples only for the Bactec 12B, the recovery of Map decreased as time of exposure increased. Based on these findings, M-7H10 should be considered for the recovery of Map from the natural environment including water sediments where the recovery of diverse microbial species remains a challenge. Map is a robust pathogen that abides in the environment. In water treatment operations, Map associates with floccules and other particulate matter including sediments. It is also a fastidious organism, and its detection and recovery from the water environment is a laborious process and can be misleading within the abundance of other mycobacterial species owing to their close resemblance in phylogenetic traits. In the absence of a reliable recovery method, Map continues to pose public health risks through biofilm in household water tanks, hence the need for the development of a reliable recovery protocol to monitor the presence of Map in water systems in order to curtail its public health risks. Copyright © 2018 Elsevier B.V. All rights reserved.

Seasonality of Water Chemistry, Carbonate Production, and Biometric Features of Two Species of Chara in a Shallow Clear Water Lake

Directory of Open Access Journals (Sweden)

Andrzej Pukacz

2014-01-01

Full Text Available The objective of this study was to analyze the temporal variability of biometric features and the carbonate production of two charophytes: Chara polyacantha A. Braun and Chara rudis A. Braun against the background of the physical-chemical properties of water. The investigation was carried out in a small, mid-forest Lake Jasne (western Poland. It is a polymictic, mesotrophic, hardwater ecosystem dominated by charophyte vegetation. Each month, 10 individuals of each species were characterized in terms of morphometric features, fresh and dry weight, and the percentage of calcium carbonate. Additionally, physical-chemical parameters of the water were studied. The results of physical-chemical analyses indicated similar habitat conditions for both species. Despite smaller dry weight C. polyacantha was characterized by greater morphological variability and higher rates of growth and percentage share of calcium carbonate in dry mass than C. rudis. The percentage of calcium carbonates in dry mass did not differ significantly between the species and exceeded 60%, reaching the maximum (76% in C. polyacantha in July and August. For both species, distinct correlations between the structure of biomass and morphological features were found. The obtained results show the great importance of charophyte vegetation in carbon cycling and functioning of lake ecosystems.

Quantifying the anthropogenic and climatic contributions to changes in water discharge and sediment load into the sea: A case study of the Yangtze River, China.

Science.gov (United States)

Zhao, Yifei; Zou, Xinqing; Gao, Jianhua; Xu, Xinwanghao; Wang, Chenglong; Tang, Dehao; Wang, Teng; Wu, Xiaowei

2015-12-01

Based on data from the Datong hydrological station and 147 meteorological stations, the influences of climate change and human activities on temporal changes in water discharge and sediment load were examined in the Yangtze River basin from 1953 to 2010. The Mann-Kendall test, abrupt change test (Mann-Kendall and cumulative anomaly test), and Morlet wavelet method were employed to analyze the water discharge and sediment load data measured at the Datong hydrological station. The results indicated that the annual mean precipitation and water discharge exhibited decreasing trends of -0.0064 mm/10 yr and -1.41×10(8) m3/yr, respectively, and that the water sediment load showed a significant decreasing trend of -46.5×10(6) t/yr. Meanwhile, an abrupt change in the water discharge occurred in 2003. The sediment load also exhibited an abrupt change in 1985. From 1970 to 2010, the climate change and human activities contributed 72% and 28%, respectively, to the water discharge reduction. The human-induced decrease in the sediment load was 914.03×10(6) t/yr during the 1970s and 3301.79×10(6) t/yr during the 2000s. The contribution from human activities also increased from 71% to 92%, especially in the 1990s, when the value increased to 92%. Climate change and human activities contributed 14% and 86%, respectively, to the sediment load reduction. Inter-annual variations in water discharge and sediment load were affected by climate oscillations and human activities. The effect of human activities on the sediment load was considerably greater than those on water discharge in the Yangtze River basin. Copyright © 2015 Elsevier B.V. All rights reserved.

Persistence profile of polyaromatic hydrocarbons in shallow and deep Gulf waters and sediments: Effect of water temperature and sediment–water partitioning characteristics

International Nuclear Information System (INIS)

Tansel, B.; Fuentes, C.; Sanchez, M.; Predoi, K.; Acevedo, M.

2011-01-01

Highlights: ► The half-lives of PAHs in the deep waters (over 1000 m) are about twice longer than the shallow areas (100–150 m). ► In the water column, anthracene levels can decrease by 50% within 1–2 days. ► The half-lives of the PAHs in the sediments are significantly longer than those in the water column. ► The half-life of pyrene in the shallow and deep sediments is 9 and 16 years, respectively. - Abstract: Persistence profiles of selected polyaromatic hydrocarbons (PAHs) were analyzed depending on temperature variations in the water column and water–sediment interactions in the Gulf of Mexico. The PAHs studied include anthracene, fluoranthene, pyrene, and chrysene. The half-lives of PAHs in the deep waters (over 1000 m) are about twice as long as those in the shallow areas (100–150 m), and almost 2.5 times as long as those in the top layer (0–10 m) of the water column. The half-lives of the PAHs in the sediments are significantly longer. Among the PAHs studied, chrysene is the most persistent in the water column, and pyrene is the most persistent in the sediments. The half-life of chrysene in the shallow and deep waters is over 2.5 and about 5 years, respectively. For pyrene, the half-life in the shallow and deep sediments is about 9 and 16 years, respectively.

The mobility of radiocaesium in lake sediment and implications for dating studies

International Nuclear Information System (INIS)

Smith, J.T.; Nolan, L.; Ireland, D.G.; Comans, R.N.J.

1998-01-01

The experiments to study the uptake of radiocaesium by sediment cores from Esthwaite Water, Cumbria, UK in order to develop a model to simultaneously describe uptake of radiocaesium from the water column and diffusion of activity within the sediment has been carried out. By measuring the rate of diffusion of activity through the sediment and sediment pore waters as a function of time the validity of the equilibrium approach to modelling radiocaesium sorption and mobility in sediments has been assessed. By comparison with in situ measurements was found, that rates of diffusion of activity introduced by diffusion across the sediment-water interface (as in the experiments) were approximately one order of magnitude greater than those determined from Chernobyl and weapons test activity-depth profiles. Modelling of the removal of activity from Esthwaite Water showed that the majority of the activity was transported to the sediments by attachment to and settling of suspended particles. It is concluded that activity deposited on particulates (forming the majority of activity observed in situ) was more strongly bound to sediments than that introduced by direct diffusion. This explanation is consistent with observed 'two-phase' 137 Cs profiles in sediments. Predictions of future evolution of the weapons test peak are made on the basis of these studies. It is shown that the peak in the activity-depth profile will remain an important marker for dating studies for the forseeable future

Discharge, sediment, and water chemistry in Clear Creek, western Nevada, water years 2013–16

Science.gov (United States)

Huntington, Jena M.; Riddle, Daniel J.; Paul, Angela P.

2018-05-01

Clear Creek is a small stream that drains the eastern Carson Range near Lake Tahoe, flows roughly parallel to the Highway 50 corridor, and discharges to the Carson River near Carson City, Nevada. Historical and ongoing development in the drainage basin is thought to be affecting Clear Creek and its sediment-transport characteristics. Previous studies from water years (WYs) 2004 to 2007 and from 2010 to 2012 evaluated discharge, selected water-quality parameters, and suspended-sediment concentrations, loads, and yields at three Clear Creek sampling sites. This report serves as a continuation of the data collection and analyses of the Clear Creek discharge regime and associated water-chemistry and sediment concentrations and loads during WYs 2013–16.Total annual sediment loads ranged from 870 to 5,300 tons during WYs 2004–07, from 320 to 1,770 tons during WYs 2010–12, and from 50 to 200 tons during WYs 2013–16. Ranges in annual loads during the three study periods were not significantly different; however, total loads were greater during 2004–07 than they were during 2013–16. Annual suspended-sediment loads in WYs 2013–16 showed no significant change since WYs 2010–12 at sites 1 (U.S. Geological Survey reference site 10310485; Clear Creek above Highway 50, near Spooner Summit, Nevada) or 2 (U.S. Geological Survey streamgage 10310500; Clear Creek above Highway 50, near Spooner Summit, Nevada), but significantly lower loads at site 3 (U.S. Geological Survey site 10310518; Clear Creek at Fuji Park, at Carson City, Nevada), supporting the theory of sediment deposition between sites 2 and 3 where the stream gradient becomes more gradual. Currently, a threshold discharge of about 3.3 cubic feet per second is required to mobilize streambed sediment (bedload) from site 2 in Clear Creek. Mean daily discharge was significantly lower in 2010–12 than in 2004–07 and also significantly lower in 2013–16 than in 2010–12. During this study, lower bedload, and

Toxicological assessment of aquatic ecosystems: application to watercraft contaminants in shallow water environments

Science.gov (United States)

Winger, P.V.; Kemmish, Michael J.

2002-01-01

Recreational boating and personal watercraft use have the potential to adversely impact shallow water systems through contaminant release and physical disturbance of bottom sediments. These nearshore areas are often already degraded by surface runoff, municipal and industrial effluents, and other anthropogenic activities. For proper management, information is needed on the level of contamination and environmental quality of these systems. A number of field and laboratory procedures can be used to provide this much needed information. Contaminants, such as metals, pesticides, polychlorinated biphenyls and polycyclic aromatic hydrocarbons, entering aquatic environments generally attach to particulate matter that eventually settles and becomes incorporated into the bottom sediments. Because bottom sediments serve as a sink and as a source for contaminants, environmental assessments generally focus on this matrix. While contaminant residues in sediments and sediment pore waters can reflect environmental quality, characteristics of sediment (redox potential, sediment/pore-water chemistry, acid volatile sulfides, percent organic matter, and sediment particle size) influence their bioavailability and make interpretation of environmental significance difficult. Comparisons of contaminant concentrations in pore water (interstitial water) and sediment with water quality criteria and sediment quality guidelines, respectively, can provide insight into potential biological effects. Laboratory bioaccumulation studies and residue concentrations in resident or caged biota also yield information on potential biological impacts. The usefulness of these measurements may increase as data are developed relating in-situ concentrations, tissue residue levels, and biological responses. Exposure of test organisms in situ or to field-collected sediment and pore water are additional procedures that can be used to assess the biological effects of contaminants. A battery of tests using multi-species

A SEDIMENT TOXICITY METHOD USING LEMNA MINOR, DUCKWEED

Science.gov (United States)

We developed a Lemna minor sediment toxicity test method to assess sediment contaminants which may affect plants. This 96-hour test used 15 ml of sediment and 2 ml of overlying water which was renewed after 48 hours. Sand was used as the control sediment and also to dilute test ...

Comparative genotoxicity testing of Rhine river sediment extracts using the comet assay with permanent fish cell lines (RTG-2 and RTL-W1) and the Ames test

Energy Technology Data Exchange (ETDEWEB)

Kosmehl, T.; Braunbeck, T.; Hollert, H. [Dept. of Zoology, Aquatic Ecology and Toxicology Section, Univ. of Heidelberg (Germany); Krebs, F.; Manz, W. [German Federal Inst. of Hydrology, Koblenz (Germany); Erdinger, L. [Dept. for Hygiene and Medical Microbiology, Inst. for Hygiene, Univ. of Heidelberg (Germany)

2004-07-01

Whilst at least in Germany assessment strategies on the basis of chemical analysis and acute toxicity data dominated the last decades, the development of more specific biological endpoints and biomarkers in ecotoxicology is required in order to arrive at a good ecological potential and good chemical status of surface waters in the European river basins until the year 2015, as required by the European Water Framework Directive. Since sediments have for long been known to function both as a sink and as a source of pollutants in aquatic systems, and since part of the particle-associated substances have frequently been demonstrated to cause mutagenic and carcinogenic effects in aquatic organisms, particularly in fish, there is, among other requirements, an urgent need to develop, standardize and implement integrated vertebrate-based test systems addressing genotoxicity into recent sediment investigation strategies. Thus, the present study was designed to compare the suitability of two commonly used test systems, the comet assay and the Ames test, for the evaluation of the ecotoxicological burden of surface and core sediment samples from the river Rhine. Methods (or main features). In order to determine the importance of inherent enzymatic activities, two permanent fish cell lines with different biotransformation capacities, RTL-W1 and RTG-2, were compared with respect to their capability of detecting genotoxic effects in 18 surface and core sediment samples from 9 locations along the river Rhine in the comet assay with and without exogenous bioactivation. For further comparison, as a prokaryotic mutagenicity assay, the Salmonella plate incorporation assay (Ames test) with the test strains TA98 and TA100 with and without exogenous metabolic activation was used. Results and discussion. Whereas all sediment extracts induced genotoxic effects in the comet assay with RTL-W1 cells, only 12 out of 18 sediment extracts revealed significant genotoxicity in the tests with the

Marine sediments as a sink, and contaminated sediments as a diffuse source of radionuclides

International Nuclear Information System (INIS)

Salbu, B.; Borretzen, P.

1997-01-01

Full text: Marine sediments may act as a sink for radionuclides originating from atmospheric fallout (e.g. Chernobyl accident), for radionuclides in discharges from nuclear installations (e.g. Sellafield, UK) for river transported radionuclides, and radionuclides released from nuclear waste dumped at sea (e.g. fjords at Novaya Zemlya). In order to assess short and long term consequences of radionuclides entering the marine ecosystem, the role of sediments as a relatively permanent sink and the potential for contaminated sediments to act as a diffuse source should be focused. The retention of radionuclides in sediments will depend on the source term, i.e. the physico-chemical forms of radionuclides entering the system and on interactions with various sediment components. Radionuclides associated with particles or aggregating polymers are removed from the water phase by sedimentation, while sorption to surface sediment layers is of relevance for ionic radionuclide species including negatively charged colloids. With time, transformation processes will influence the mobility of radionuclides in sediments. The diffusion into mineral lattices will increase fixation, while the influence of for instance red/ox conditions and bio-erosion may mobilize radionuclides originally fixed in radioactive particles. Thus, information of radionuclides species, surface interactions, transformation processes and kinetics is essential for reducing the uncertainties in marine transfer models. Dynamic model experiments where chemically well defined tracers are added to a sea water-marine sediment system are useful for providing information on time dependent interactions and distribution coefficients. When combined with sequential extraction techniques, information on mobility and rate of fixation is subsequently attained. In the present work experimental results from the Irish Sea and the Kara Sea will be discussed

In situ sampling of interstitial water from lake sediments

NARCIS (Netherlands)

Brinkman, Albertus G.; van Raaphorst, Wim; Lijklema, Lambertus

1982-01-01

A sampler with a relatively high resolution has been developed, which allows interstitial water to be obtained from lake sediments at well defined depths, without serious disturbance of sediment structure. Oxidation effects are excluded. Sampling time is in the order of a day. Installation requires

Levels of trace metals in water and sediment from Tyume River and ...

African Journals Online (AJOL)

Levels of trace metals (Cd, Pb, Co, Zn Cu and Ni) were determined in water and sediment ... mg/l) and Pb (0.021 ± 0.004 to 0.035 ± 0.001 mg/l) were found in the river water, ... Key words: trace metals, water, sediment, farmland, Tyume River

Hydrous Ferric Oxides in Sediment Catalyze Formation of Reactive Oxygen Species during Sulfide Oxidation

Directory of Open Access Journals (Sweden)

Sarah A. Murphy

2016-11-01

Full Text Available Abstract: This article describes the formation of reactive oxygen species as a result of the oxidation of dissolved sulfide by Fe(III-containing sediments suspended in oxygenated seawater over the pH range 7.00 and 8.25. Sediment samples were obtained from across the coastal littoral zone in South Carolina, US, at locations from the beach edge to the forested edge of a Spartina dominated estuarine salt marsh and suspended in aerated seawater. Reactive oxygen species (superoxide and hydrogen peroxide production was initiated in sediment suspensions by the addition of sodium bisulfide. The subsequent loss of HS-, formation of Fe(II (as indicated by Ferrozine, and superoxide and hydrogen peroxide were monitored over time. The concentration of superoxide rose from the baseline and then persisted at an apparent steady state concentration of approximately 500 nanomolar at pH 8.25 and 200 nanomolar at pH 7.00 respectively until >97% hydrogen sulfide was consumed. Measured superoxide was used to predict hydrogen peroxide yield based on superoxide dismutation. Dismutation alone quantitatively predicted hydrogen peroxide formation at pH 8.25 but over predicted hydrogen peroxide formation at pH 7 by a factor of approximately 102. Experiments conducted with episodic spikes of added hydrogen peroxide indicated rapid hydrogen peroxide consumption could account for its apparent low instantaneous yield, presumably the result of its reaction with Fe(II species, polysulfides or bisulfite. All sediment samples were characterized for total Fe, Cu, Mn, Ni, Co and hydrous ferric oxide by acid extraction followed by mass spectrometric or spectroscopic characterization. Sediments with the highest loadings of hydrous ferric oxide were the only sediments that produced significant dissolved Fe(II species or ROS as a result of sulfide exposure.

Fate modeling of mercury species and fluxes estimation in an urban river

International Nuclear Information System (INIS)

Tong, Yindong; Zhang, Wei; Chen, Cen; Chen, Long; Wang, Wentao; Hu, Xindi; Wang, Huanhuan; Hu, Dan; Ou, Langbo; Wang, Xuejun; Wang, Qiguang

2014-01-01

The fate and transfer of mercury in urban river is an important environmental concern. In this study, QWASI (Quantitative Water–Air–Sediment Interaction) model was selected to estimate the levels of total mercury and three mercury species in water and sediment, and was used to quantify the fluxes of mercury at water/air and sediment/water interfaces of an urban river. The predicted mercury levels in water and sediments were closed to the measured values. Water inflow, re-suspension of sediment and diffusion from sediment to water are major input sources of mercury in water. The net mercury transfer flux from water to air was 0.16 ng/(m 2 h). At the sediment/water interface, a net total mercury transfer of 1.32 ng/(m 2 h) from water to sediment was seen. In addition to the existing dynamic flux chambers measurement, this model method could provide a new perspective to identify the distribution and transfer of mercury in the urban river. -- Highlights: • QWASI could be a good tool to quantify transfer and fate of mercury in environment. • Distribution and flux of mercury species in an urban river was modeled. • Mercury in water mainly came from water inflow, sediment re-suspension and diffusion. • Net mercury transfer from water to air and sediment were 0.16 and 1.32 ng/(m 2 h). -- Quantitative Water–Air–Sediment Interaction model was used to quantify the transfer and fate of mercury in an urban river

Environmental contamination of Gorganrood Water and Sediment in district of Gonbad-Kavoos City

Directory of Open Access Journals (Sweden)

Giti Forghani

2014-11-01

Gonbad-e-Kavoos district. Material and Methods To evaluate the quality of water and sediments at the study area, 10 water and sediment samples were collected in the month of November in year 2012 by standard methods. The physicochemical parameters of water samples including pH and electrical conductivity (EC were determined in situ using portable conductivity and pH meter. At each sampling station, water samples were collected in 1-litre prewashed polyethylene bottles. Water samples were filtered using a vacuum pump and 0.45μm pore-size filter papers in order to separate particulate matter. The filtered samples were then split into two portions: one portion was acidified with HNO3 for dissolved element measurement and the second unacidified portion was used for determination of dissolved anions. The samples were kept at 4°C prior to analysis.The concentration of major ions in water samples was measure using the standard methods: Ca and Mg were determined using titration with EDTA, Cl was measured using titration with AgNO3 and bicarbonate was determined using titration with HCl. Flame photometry was applied for determining Na and K concentration. Nitrate and phosphate values were measured using spectrophotometer. Cationic and anionic charge balance was calculated as a proof for the precision of the data. Total dissolved solid (TDS was measured using evaporation method. The piper diagram was used to assess the water type. Sediment samples were air dried, and then, the Mg2+ (10.4> Ca2+ (7.06> K+ (0.1 and SO42- (13.9> Cl- (13.2> HCO3- (6. The piper diagram shows that the water type in the city district samples is Na-Cl, but in other samples is Na-SO42-, perhaps due to the effect of municipal wastewaters discharge on water type. Despite the extensive agricultural activities in the Gorganrood basin, the nitrate concentration of the samples are below the maximum allowable concentration for drinking usage (50 mg/l, WHO 2011, perhaps due to the denitrification process

Sediment Supply as a Control on Plant-Morphodynamic Interactions

Science.gov (United States)

Manners, R.; Wilcox, A. C.; Kui, L.; Stella, J. C.; Lightbody, A.; Sklar, L. S.

2014-12-01

The caliber and quantity of sediment delivered to a channel influences its size and shape, yet we know little about how the sediment supply affects rivers whose geomorphic form is influenced by riparian vegetation. We present results from flume experiments that test the impact of sediment supply on plant-morphodynamic interactions. We introduced two sediment supply conditions to a 28-meter long, sand bedded flume (60 cm wide and 71 cm deep) at the UC-Berkeley Richmond Field Station: equilibrium (balance between sediment transport and supply) and deficit (transport exceeds sediment supply). We conducted ten runs with different riparian seedling configurations (individual plants or patches) and species (tamarisk or cottonwood), and stem and leaf density (0.003-0.47 cm2/cm2), under both sediment supply conditions. Plant species, size, and configuration were important in predicting the topographic adjustments that occurred during our experiments. These influences may be attributed to differences in plant morphology; tamarisk is shrubby while cottonwood is more tree-like, with a single stem and leaves concentrated higher on the plant. The plant-morphodynamic relationship, however, differed for the two sediment supply conditions. During sediment equilibrium, only patches of cottonwood served as sediment sinks compared to an unvegetated bed, but tamarisk patches had no impact on the sediment mass balance. During sediment deficit, in contrast, tamarisk patches accumulated more sediment than unvegetated beds. Stem and leaf density also controlled changes in bed elevation. During equilibrium conditions, increasing the density of cottonwood stems and leaves resulted in greater bed degradation. Conversely, aggradation occurred with increases in the density of tamarisk. For sediment deficit conditions, the relationship between stem and leaf density and the rate of bed change was negative for both species (i.e., higher density resulted in faster rate of scour). The shifting