Evaluation of leachate dissolved organic nitrogen discharge effect on wastewater effluent quality.

Science.gov (United States)

Bolyard, Stephanie C; Reinhart, Debra R

2017-07-01

Nitrogen is limited more and more frequently in wastewater treatment plant (WWTP) effluents because of the concern of causing eutrophication in discharge waters. Twelve leachates from eight landfills in Florida and California were characterized for total nitrogen (TN) and dissolved organic nitrogen (DON). The average concentration of TN and DON in leachate was approximately 1146mg/L and 40mg/L, respectively. Solid-phase extraction was used to fractionate the DON based on hydrophobic (recalcitrant fraction) and hydrophilic (bioavailable fraction) chemical properties. The average leachate concentrations of bioavailable (bDON) and recalcitrant (rDON) DON were 16.5mg/L and 18.4mg/L, respectively. The rDON fraction was positively correlated, but with a low R 2 , with total leachate apparent color dissolved UV 254 , chemical oxygen demand (COD), and humic acid (R 2 equals 0.38, 0.49, and 0.40, respectively). The hydrophobic fraction of DON (rDON) was highly colored. This fraction was also associated with over 60% of the total leachate COD. Multiple leachate and wastewater co-treatment simulations were carried out to assess the effects of leachate on total nitrogen wastewater effluent quality using removals for four WWTPs under different scenarios. The calculated pass through of DON suggests that leachate could contribute to significant amounts of nitrogen discharged to aquatic systems. Copyright © 2017 Elsevier Ltd. All rights reserved.

Measuring and understanding total dissolved gas pressure in groundwater

Science.gov (United States)

Ryan, C.; Roy, J. W.; Randell, J.; Castellon, L.

2009-05-01

Since dissolved gases are important to a number of aspects of groundwater (e.g. age dating, active or passive bioremediation, greenhouse gas fluxes, understanding biogeochemical processes involving gases, assessing potential impacts of coal bed methane activities), accurate concentration measurements, and understanding of their subsurface behaviour are important. Researchers have recently begun using total dissolved gas pressure (TGP) sensor measurements, more commonly applied for surface water monitoring, in concert with gas composition analyses to estimate more accurate groundwater gas concentrations in wells. We have used hydraulic packers to isolate the well screens where TDP is being measured, and pump tests to indicate that in-well degassing may reduce TDG below background groundwater levels. Thus, in gas-charged groundwater zones, TGPs can be considerably underestimated in the absence of pumping or screen isolation. We have also observed transient decreased TGPs during pumping that are thought to result from ebullition induced when the water table or water level in the well is lowered below a critical hydrostatic pressure.

Concentration and flux of total and dissolved phosphorus, total nitrogen, chloride, and total suspended solids for monitored tributaries of Lake Champlain, 1990-2012

Science.gov (United States)

Medalie, Laura

2014-01-01

Annual and daily concentrations and fluxes of total and dissolved phosphorus, total nitrogen, chloride, and total suspended solids were estimated for 18 monitored tributaries to Lake Champlain by using the Weighted Regressions on Time, Discharge, and Seasons regression model. Estimates were made for 21 or 23 years, depending on data availability, for the purpose of providing timely and accessible summary reports as stipulated in the 2010 update to the Lake Champlain “Opportunities for Action” management plan. Estimates of concentration and flux were provided for each tributary based on (1) observed daily discharges and (2) a flow-normalizing procedure, which removed the random fluctuations of climate-related variability. The flux bias statistic, an indicator of the ability of the Weighted Regressions on Time, Discharge, and Season regression models to provide accurate representations of flux, showed acceptable bias (less than ±10 percent) for 68 out of 72 models for total and dissolved phosphorus, total nitrogen, and chloride. Six out of 18 models for total suspended solids had moderate bias (between 10 and 30 percent), an expected result given the frequently nonlinear relation between total suspended solids and discharge. One model for total suspended solids with a very high bias was influenced by a single extreme value; however, removal of that value, although reducing the bias substantially, had little effect on annual fluxes.

Total alkaloid content in various fractions of Tabernaemonata sphaerocarpa Bl. (Jembirit) leaves

Science.gov (United States)

Salamah, N.; Ningsih, D. S.

2017-11-01

Tabernaemontana sphaerocarpa Bl. (Jembirit) is one of the Apocynaceae family plants containing alkaloid compound. Traditionally, it is used as an anti-inflammatory medicine. It is found to have a new bisindole alkaloid compound that shows a potent cytotoxic activity in human cancer. This study aimed to know the total alkaloid content in some fractions of ethanolic extract of T. sphaerocarpa Bl. leaf powder was extracted by maceration method in 70% ethanol solvent. Then, the extract was fractionated in a separatory funnel using water, ethyl acetate, and hexane. The total alkaloid content in each fraction was analyzed with visible spectrophotometric methods based on the reaction with Bromocresol Green (BCG). The total alkaloids in water fraction and ethyl acetate fraction were (0.0312±0.0009)% and (0.0281±0.0014)%, respectively. Meanwhile, the total alkaloid content in hexane was not detected. The statistical analysis, performed in SPSS, resulted in a significant difference between the total alkaloids in water fraction and ethyl acetate fraction. The total alkaloid in water fraction of T. sphaerocarpa Bl. was higher than the one in ethyl acetate fraction.

Distribution of Cd, Pb and Cu between dissolved fraction, inorganic particulate and phytoplankton in seawater of Terra Nova Bay (Ross Sea, Antarctica) during austral summer 2011-12.

Science.gov (United States)

Illuminati, S; Annibaldi, A; Romagnoli, T; Libani, G; Antonucci, M; Scarponi, G; Totti, C; Truzzi, C

2017-10-01

During the austral summer 2011-2012, the metal quotas of Cd, Pb and Cu in the phytoplankton of Terra Nova Bay (TNB, Antarctica) were measured for the first time. Evolution of all the three metal distributions between dissolved and particulate fractions during the season was also evaluated. Metal concentrations were mainly affected by the dynamic of the pack ice melting and phytoplankton activity. In mid-December when TNB area was covered by a thick pack ice layer and phytoplankton activity was very low, all the three metals were present mainly in their dissolved species. When the pack ice started to melt and the water column characteristics became ideal (i.e. moderate stratification, ice free area), the phytoplankton bloom occurred. Cd showed a nutrient-type behaviour with dissolved and particulate fractions mainly influenced by phytoplankton activity. Cd quota showed a mean value of 0.12 ± 0.07 nmol L -1 (30-100% of the total particulate). Also Cu showed a nutrient-type behaviour, with its quota in phytoplankton varying between 0.08 and 2.1 nmol L -1 (20-100% of the total particulate). Pb features the typical distribution of a scavenged element with very low algal content (0.03 ± 0.02 nmol L -1 , representing 20-50% of the total particulate). The vertical distribution of this element was influenced by several factors (e.g. pack ice melting, atmospheric inputs), the phytoplankton activity affecting Pb behaviour only partially. Metal:C ratios provide valuable information on the biological requirements for Cd, Pb and Cu, leading us to better understand their biogeochemical cycles. Copyright © 2017 Elsevier Ltd. All rights reserved.

Measurement of total dissolved solids using electrical conductivity

International Nuclear Information System (INIS)

Ray, Vinod K.; Jat, J.R.; Reddy, G.B.; Balaji Rao, Y.; Phani Babu, C.; Kalyanakrishnan, G.

2017-01-01

Total dissolved solids (TDS) is an important parameter for the disposal of effluents generated during processing of different raw materials like Magnesium Di-uranate (MDU), Heat Treated Uranium Peroxide (HTUP), Sodium Di-uranate (SDU) in Uranium Extraction plant and Washed and Dried Frit (WDF) in Zirconium Extraction Plant. The present paper describes the use of electrical conductivity for determination of TDS. As electrical conductivity is matrix dependent property, matrix matched standards were prepared for determination of TDS in ammonium nitrate solution (AN) and mixture of ammonium nitrate and ammonium sulphate (AN/AS) and results were found to be in good agreement when compared with evaporation method. (author)

Warming and organic matter sources impact the proportion of dissolved to total activities in marine extracellular enzymatic rates

KAUST Repository

Baltar, Federico

2017-04-19

Extracellular enzymatic activities (EEAs) are the rate-limiting step in the degradation of organic matter. Extracellular enzymes can be found associated to cells or dissolved in the surrounding water. The proportion of cell-free EEA constitutes in many marine environments more than half of the total activity. This high proportion causes an uncoupling between hydrolysis rates and the actual bacterial activity. However, we do not know what factors control the proportion of dissolved relative to total EEA, nor how this may change in the future ocean. To resolve this, we performed laboratory experiments with water from the Great Barrier Reef (Australia) to study the effects of temperature and dissolved organic matter sources on EEA and the proportion of dissolved EEA. We found that warming increases the rates of organic matter hydrolysis and reduces the proportion of dissolved relative to total EEA. This suggests a potential increase of the coupling between organic matter hydrolysis and heterotrophic activities with increasing ocean temperatures, although strongly dependent on the organic matter substrates available. Our study suggests that local differences in the organic matter composition in tropical coastal ecosystems will strongly affect the proportion of dissolved EEA in response to ocean warming.

Correlation Between Total Flavonoid Contents and Macrophage Phagocytosis Activity of Fractions From Faloak (Sterculia quadrifida R.Br. Barks Ethanolic Extract In Vitro

Directory of Open Access Journals (Sweden)

Rima Munawaroh

2018-04-01

Full Text Available On Timor island, Nusa Tenggara Timur, faloak barks (Sterculia quadrifida R.Br. has been used empirically to restore stamina. Faloak bark ethanolic extract proved to have immunomodulatory activity in vitro, which can increase macrophage phagocytosis activity. This research aimed: (i to determine the immunomodulatory active fraction of faloak bark ethanolic extract, (ii to determine the total flavonoid contents of faloak extract and fractions, and (iii to evaluate the correlation of the total flavonoid contents of those extract and fractions with their macrophage phagocytosis activity. The simplisia powder is macerated with 96% ethanol. The extract was dissolved in methanol:water (9:1v/v was then subsequently partitioned with n-hexane, ethyl acetate, and water to obtain n-hexane fraction, ethyl acetate fraction, water fraction, and insoluble fraction. Faloak extract and fractions at concentration 62,5; 125; 250; 500μg/mL were tested for their effect on the peritoneal macrophage phagocytosis of Balb/c mice in vitro by the latex beads method. Phagocytosis capacity and phagocytosis index were analyzed using one-way anova and post hoc Tukey HSD test with 95% confidence level. The results showed that ethyl acetate fraction had the highest macrophage phagocytosis capacity and the highest total flavonoid content compared to other fractions. The highest macrophage phagocytosis capacity of ethyl acetate fraction at concentration of 250 μg/mL was 51,94±4,67%, this value was significantly different from cell control (7,50±1,29%, negative controls of 0,0625% dimethylsulphoxide (6,25±0,36%, as well as positive control of 200 μg/mL echinaceae extract syrup® (9,97±0,33%. The total flavonoid content of ethyl acetate fraction determined by aluminum chloride method was 4,290±0.029 mg of quercetin equivalent/g fraction. There was a positive and strong correlation between the total flavonoid content of these extract and fractions with their macrophage

Titanium distribution in swimming pool water is dominated by dissolved species

International Nuclear Information System (INIS)

David Holbrook, R.; Motabar, Donna; Quiñones, Oscar; Stanford, Benjamin; Vanderford, Brett; Moss, Donna

2013-01-01

The increased use of titanium dioxide nanoparticles (nano-TiO 2 ) in consumer products such as sunscreen has raised concerns about their possible risk to human and environmental health. In this work, we report the occurrence, size fractionation and behavior of titanium (Ti) in a children's swimming pool. Size-fractionated samples were analyzed for Ti using ICP-MS. Total titanium concentrations ([Ti]) in the pool water ranged between 21 μg/L and 60 μg/L and increased throughout the 101-day sampling period while [Ti] in tap water remained relatively constant. The majority of [Ti] was found in the dissolved phase (<1 kDa), with only a minor fraction of total [Ti] being considered either particulate or microparticulate. Simple models suggest that evaporation may account for the observed variation in [Ti], while sunscreen may be a relevant source of particulate and microparticule Ti. Compared to diet, incidental ingestion of nano-Ti from swimming pool water is minimal. -- Highlights: •Total titanium concentrations in unfiltered swimming pool water ranged between 21 and 60 μg/L. •Evaporation of the swimming pool water is suspected of causing a temporal increase in [Ti]. •The vast majority of Ti is found in the dissolved phase (<1 kD). •Swimming pools are not a significant Ti source for human exposure via ingestion. -- In children's swimming pool water, the majority of titanium is found in the dissolved phase

Fractionation and characterization of saccharides and lignin components in wood prehydrolysis liquor from dissolving pulp production.

Science.gov (United States)

Wang, Zhaojiang; Wang, Xiaojun; Jiang, Jungang; Fu, Yingjuan; Qin, Menghua

2015-08-01

Saccharides and lignin components in prehydrolysis liquor (PHL) from kraft-based dissolving pulp production was characterized after being fractionated using membrane filtration. The results showed that the membrane filtration provided a method for organics fractionation with considerable recovery rate, but exhibited some disadvantages. Besides the limited ability in purifying oligosaccharides (OS) due to the overlaps of molecular weight distribution with lignin components, the membrane filtration could not improve the homogeneity of OS as indicated by the analysis of chemical compositions and the degree of polymerization (DP), which may be ascribed to the linear conformation of OS. The characterization of lignin components indicated a great potential for polymer industry because of the remarkable content of phenolic hydroxyl groups (PhOH), especially for low molecular weight (LMW) fraction. It was concluded the organics in PHL provided streams of value-added chemicals. However, the practical significance thereof can be realized and maximized only when they are successfully and completely fractionated. Copyright © 2015 Elsevier Ltd. All rights reserved.

COMMUNITY SCALE STREAM TAXA SENSITIVITIES TO DIFFERENT COMPOSITIONS OF EXCESS TOTAL DISSOLVED SOLIDS

Science.gov (United States)

Model stream chronic dosing studies (42 d) were conducted with three total dissolved solids (TDS) recipes. The recipes differed in composition of major ions. Community scale emergence was compared with single-species responses conducted simultaneously using the whole effluent tox...

Chemical characterization of fractions of dissolved humic substances from a marginal sea—a case from the Southern Yellow Sea

Science.gov (United States)

Zhang, Yaoling; Yang, Keli; Du, Jinzhou; Zhang, Fenfen; Dong, Yaping; Li, Wu

2018-03-01

Marine dissolved organic matter (DOM) is one of the largest dynamic pools of organic carbon in the global carbon cycle, yet DOM is still chemically poorly characterized. To better understand the origin, composition, and cycling of DOM in the China marginal sea, dissolved humic substances (DHS) were isolated from seawaters in two locations in the Southern Yellow Sea. The DHS were subdivided into fulvic acids (FAs), humic acids (HAs) and the XAD-4 fractions. Complementary analytical approaches were used to characterize the isolated DHS samples including stable carbon isotopic composition, Fourier transform infrared spectroscopy (FTIR), 13C cross polarization magic angle spinning (CP/MAS) nuclear magnetic resonance (NMR), and pyrolysis gas chromatography-mass spectrometry (Py-GC/MS). The results demonstrated that both DHS samples encountered the influences from marine source, indicating that algal and microbial-derived materials are the predominant precursors for the studied samples. The three fractions of DHS showed different properties. FAs presented more aromatic features, whereas HAs contained more aliphatic lipids and proteinaceous materials. The XAD-4 fractions were enriched in 13C and contained more carbohydrates but less aromatic compounds. The lower molecular weight and higher heteroatom content and number of carboxyl groups for the XAD-4 fractions may give them considerable geochemical significance for aspects of trace metal species, bioavailability of pollutants, mineral weathering and water acidification in marine environments.

Use of normalized total dose to represent the biological effect of fractionated radiotherapy

Energy Technology Data Exchange (ETDEWEB)

Flickinger, J C; Kalend, A [Pittsburgh University School of Medicine (USA). Department of Radiation Oncology Pittsburg Cancer Institute (USA)

1990-03-01

There are currently a number of radiobiological models to account for the effects of dose fractionation and time. Normalized total dose (NTD) is not another new model but is a previously reported, clinically useful form in which to represent the biological effect, determined by any specific radiobiological dose-fractionation model, of a course of radiation using a single set of standardized, easily understood terminology. The generalized form of NTD reviewed in this paper describes the effect of a course of radiotherapy administered with nonstandard fractionation as the total dose of radiation in Gy that could be administered with a given reference fractionation such as 2 Gy per fraction, 5 fractions per week that would produce an equivalent biological effect (probability of complications or tumor control) as predicted by a given dose-fractionation formula. The use of normalized total dose with several different exponential and linear-quadratic dose-fraction formulas is presented. (author). 51 refs.; 1 fig.; 1 tab.

Use of normalized total dose to represent the biological effect of fractionated radiotherapy

International Nuclear Information System (INIS)

Flickinger, J.C.; Kalend, A.

1990-01-01

There are currently a number of radiobiological models to account for the effects of dose fractionation and time. Normalized total dose (NTD) is not another new model but is a previously reported, clinically useful form in which to represent the biological effect, determined by any specific radiobiological dose-fractionation model, of a course of radiation using a single set of standardized, easily understood terminology. The generalized form of NTD reviewed in this paper describes the effect of a course of radiotherapy administered with nonstandard fractionation as the total dose of radiation in Gy that could be administered with a given reference fractionation such as 2 Gy per fraction, 5 fractions per week that would produce an equivalent biological effect (probability of complications or tumor control) as predicted by a given dose-fractionation formula. The use of normalized total dose with several different exponential and linear-quadratic dose-fraction formulas is presented. (author). 51 refs.; 1 fig.; 1 tab

Simultaneous quantification of dissolved organic carbon fractions and copper complexation using solid-phase extraction

International Nuclear Information System (INIS)

McElmurry, Shawn P.; Long, David T.; Voice, Thomas C.

2010-01-01

Trace metal cycling in natural waters is highly influenced by the amount and type of dissolved organic C (DOC). Although determining individual species of DOC is unrealistic, there has been success in classifying DOC by determining operationally defined fractions. However, current fractionation schemes do not allow for the simultaneous quantification of associated trace metals. Using operational classifications, a scheme was developed to fractionate DOC based on a set of seven solid-phase extraction (SPE) cartridges. The cartridges isolated fractions based on a range of specific mechanisms thought to be responsible for DOC aggregation in solution, as well as molecular weight. The method was evaluated to determine if it can identify differences in DOC characteristics, including differences in Cu-DOC complexation. Results are that: (1) cartridge blanks were low for both DOC and Cu, (2) differences are observed in the distribution of DOC amongst the fractions from various sources that are consistent with what is known about the DOC materials and the mechanisms operative for each cartridge, (3) when present as a free cation, Cu was not retained by non-cationic cartridges allowing the method to be used to assess Cu binding, (4) the capability of the method to provide quantitative assessment of Cu-DOC complexation was demonstrated for a variety of DOC standards, (5) Cu was found to preferentially bind with high molecular weight fractions of DOC, and (6) estimated partitioning coefficients and conditional binding constants for Cu were similar to those reported elsewhere. The method developed describes DOC characteristics based on specific bonding mechanisms (hydrogen, donor-acceptor, London dispersion, and ionic bonding) while simultaneously quantifying Cu-DOC complexation. The method provides researchers a means of describing not only the extent of DOC complexation but also how that complex will be behave in natural waters.

The Absorption of Light in Lakes: Negative Impact of Dissolved Organic Carbon on Primary Productivity

OpenAIRE

Thrane, Jan-Erik; Hessen, Dag O.; Andersen, Tom

2014-01-01

Colored dissolved organic matter (CDOM) absorbs a substantial fraction of photosynthetically active radiation (PAR) in boreal lakes. However, few studies have systematically estimated how this light absorption influences pelagic primary productivity. In this study, 75 boreal lakes spanning wide and orthogonal gradients in dissolved organic carbon (DOC) and total phosphorus (TP) were sampled during a synoptic survey. We measured absorption spectra of phytoplankton pigments, CDOM, and non-algal...

Carbon-13 fractionation observed in thermal decarboxylation of pure phenylpropiolic acid (PPA) dissolved in phenylacetylene

International Nuclear Information System (INIS)

Zielinska, A.; Zielinski, M.; Papiernik-Zielinska, H.

2003-01-01

The determinations of the 13 C fractionation in the decarboxylation of pure phenylpropiolic acid (PPA) above its melting point has been extended to higher degrees of decomposition of PPA by carrying out two-step decarboxylations to establish the maximum possible yield of carbon dioxide in the temperature interval of 423-475 K (58%). The result was compared with the yields of CO 2 for decarboxylation of PPA in phenylacetylene solvent (PA) (much smaller, temperature dependent, and equal to 11% at 406 K). The ratios of carbon isotope ratios, R so /R pf , all smaller than 1.009 in the temperature interval 405-475 K, have been analyzed formally within the branched decomposition scheme of PPA, providing carbon dioxide and a decarboxylation resistant solid chemical compound enriched in 13 C with respect to CO 2 . A general discussion of the 13 C fractionation in the decarboxylation of pure PPA and PPA dissolved in PA is supplemented by the model calculation of the maximized skeletal 13 C KIEs, in the linear chain propagation of the acetylene polymerization process. Further studies of the 13 C fractionation in condensed phases and in different hydrogen deficient and hydrogen rich media have been suggested. (author)

Automated determination of the stable carbon isotopic composition (δ13C) of total dissolved inorganic carbon (DIC) and total nonpurgeable dissolved organic carbon (DOC) in aqueous samples: RSIL lab codes 1851 and 1852

Science.gov (United States)

Révész, Kinga M.; Doctor, Daniel H.

2014-01-01

The purposes of the Reston Stable Isotope Laboratory (RSIL) lab codes 1851 and 1852 are to determine the total carbon mass and the ratio of the stable isotopes of carbon (δ13C) for total dissolved inorganic carbon (DIC, lab code 1851) and total nonpurgeable dissolved organic carbon (DOC, lab code 1852) in aqueous samples. The analysis procedure is automated according to a method that utilizes a total carbon analyzer as a peripheral sample preparation device for analysis of carbon dioxide (CO2) gas by a continuous-flow isotope ratio mass spectrometer (CF-IRMS). The carbon analyzer produces CO2 and determines the carbon mass in parts per million (ppm) of DIC and DOC in each sample separately, and the CF-IRMS determines the carbon isotope ratio of the produced CO2. This configuration provides a fully automated analysis of total carbon mass and δ13C with no operator intervention, additional sample preparation, or other manual analysis. To determine the DIC, the carbon analyzer transfers a specified sample volume to a heated (70 °C) reaction vessel with a preprogrammed volume of 10% phosphoric acid (H3PO4), which allows the carbonate and bicarbonate species in the sample to dissociate to CO2. The CO2 from the reacted sample is subsequently purged with a flow of helium gas that sweeps the CO2 through an infrared CO2 detector and quantifies the CO2. The CO2 is then carried through a high-temperature (650 °C) scrubber reactor, a series of water traps, and ultimately to the inlet of the mass spectrometer. For the analysis of total dissolved organic carbon, the carbon analyzer performs a second step on the sample in the heated reaction vessel during which a preprogrammed volume of sodium persulfate (Na2S2O8) is added, and the hydroxyl radicals oxidize the organics to CO2. Samples containing 2 ppm to 30,000 ppm of carbon are analyzed. The precision of the carbon isotope analysis is within 0.3 per mill for DIC, and within 0.5 per mill for DOC.

Fractional-Order Total Variation Image Restoration Based on Primal-Dual Algorithm

OpenAIRE

Chen, Dali; Chen, YangQuan; Xue, Dingyu

2013-01-01

This paper proposes a fractional-order total variation image denoising algorithm based on the primal-dual method, which provides a much more elegant and effective way of treating problems of the algorithm implementation, ill-posed inverse, convergence rate, and blocky effect. The fractional-order total variation model is introduced by generalizing the first-order model, and the corresponding saddle-point and dual formulation are constructed in theory. In order to guarantee $O(1/{N}^{2})$ conv...

Simplified sample treatment for the determination of total concentrations and chemical fractionation forms of Ca, Fe, Mg and Mn in soluble coffees.

Science.gov (United States)

Pohl, Pawel; Stelmach, Ewelina; Szymczycha-Madeja, Anna

2014-11-15

A simpler, and faster than wet digestion, sample treatment was proposed prior to determination of total concentrations for selected macro- (Ca, Mg) and microelements (Fe, Mn) in soluble coffees by flame atomic absorption spectrometry. Samples were dissolved in water and acidified with HNO3. Precision was in the range 1-4% and accuracy was better than 2.5%. The method was used in analysis of 18 soluble coffees available on the Polish market. Chemical fractionation patterns for Ca, Fe, Mg and Mn in soluble coffees, as consumed, using a two-column solid-phase extraction method, determined Ca, Mg and Mn were present predominantly as cations (80-93% of total content). This suggests these elements are likely to be highly bioaccessible. Copyright © 2014 Elsevier Ltd. All rights reserved.

Removal of actinides from dissolved ORNL MVST sludge using the TRUEX process

International Nuclear Information System (INIS)

Spencer, B.B.; Egan, B.Z.; Chase, C.W.

1997-07-01

Experiments were conducted to evaluate the transuranium extraction process for partitioning actinides from actual dissolved high-level radioactive waste sludge. All tests were performed at ambient temperature. Time and budget constraints permitted only two experimental campaigns. Samples of sludge from Melton Valley Storage Tank W-25 were rinsed with mild caustic (0.2 M NaOH) to reduce the concentrations of nitrates and fission products associated with the interstitial liquid. In one campaign, the rinsed sludge was dissolved in nitric acid to produce a solution containing total metal concentrations of ca. 1.8 M with a nitric acid concentration of ca. 2.9 M. About 50% of the dry mass of the sludge was dissolved. In the other campaign, the sludge was neutralized with nitric acid to destroy the carbonates, then leached with ca. 2.6 M NaOH for ca. 6 h before rinsing with the mild caustic. The sludge was then dissolved in nitric acid to produce a solution containing total metal concentrations of ca. 0.6 M with a nitric acid concentration of ca. 1.7 M. About 80% of the sludge dissolved. The dissolved sludge solution form the first campaign began gelling immediately, and a visible gel layer was observed after 8 days. In the second campaign, the solution became hazy after ca. 8 days, indicating gel formation, but did not display separated gel layers after aging for 20 days. Batch liquid-liquid equilibrium tests of both the extraction and stripping operations were conducted. Chemical analyses of both phases were used to evaluate the process. Evaluation was based on two metrics: the fraction of TRU elements removed from the dissolved sludge and comparison of the results with predictions made with the Generic TRUEX Model (GTM). The fractions of Eu, Pu, Cm, Th, and U species removed from aqueous solution in only one extraction stage were > 95% and were close to the values predicted by the GTM. Mercury was also found to be strongly extracted, with a one-stage removal of > 92%

CORRELATION OF THE PARTITIONING OF DISSOLVED ORGANIC MATTER FRACTIONS WITH THE DESORPTION OF CD, CU, NI, PB AND ZN FROM 18 DUTCH SOILS

Science.gov (United States)

Eighteen Dutch soils were extracted in aqueous solutions at varying pH. Extracts were analyzed for Cd, Cu, Ni, Pb and Zn by ICP-AES. Extract dissolved organic carbon (DOC) was also concentrated onto a macroreticular resin and fractionation into three operationally defined fract...

Temporal and spatial variations in total suspended and dissolved solids in the upper part of Manoa stream, Hawaii

NARCIS (Netherlands)

Augustijn, Dionysius C.M.; Fares, Ali; Tran, Dai Ngia

2011-01-01

Hawaiian watersheds are small, steep, and receive high intensity rainfall events of non-uniform distribution. These geographic and weather patterns result in flashy streams of strongly variable water quality even within various stream segments. Total suspended solids (TSS) and total dissolved solids

Fractionated homogenous total-body irradiation prior to bone marrow transplantation

Energy Technology Data Exchange (ETDEWEB)

Duehmke, E; Brix, F; Hebbinghaus, D; Jensen, M; Wendhausen, H; Schmitz, N

1985-03-01

At the University of Kiel, myeloid and acute lymphatic leukemia is treated since 1983 by total-body irradiation applied prior to bone marrow transplantation. Dose deviations in the midplane caused by the irregular surface and tissue inhomogeneities of the patient are reduced down to +-3.5% compared to the central ray, with the help of CT-based individual compensators. This method prevents above all an excessive dose to the lungs. The radiobiologic advantages of fractionated irradiation have been employed for all patients treated hitherto (n = 9). At present, a total body dose of 12 Gy in six fractions is applied within three days. There were no undesired acute radiogenic reactions except a mild acute mucositis found in all patients. Chronic side effects, especially in the lungs, were not demonstrated, too. However, the average follow-up time of 149 days has been rather short. One patient died from relapse of leukemia after a total dose of 10 Gy, another patient died because the transplanted bone marrow was rejected, and a third died from catheter sepsis. Six out of nine patients are in complete remission with a maximum index of Karnofsky. The limited experiences gained hitherto show that the homogeneous accelerated-fractionated total-body irradiation offers essential advantages compared to non-compensated single dose irradiation with respect to the prevention of undesired radiogenic effects in sound tissues and that its therapeutic efficacy is at least the same.

The distribution and stabilisation of dissolved Fe in deep-sea hydrothermal plumes

Science.gov (United States)

Bennett, Sarah A.; Achterberg, Eric P.; Connelly, Douglas P.; Statham, Peter J.; Fones, Gary R.; German, Christopher R.

2008-06-01

We have conducted a study of hydrothermal plumes overlying the Mid-Atlantic Ridge near 5° S to investigate whether there is a significant export flux of dissolved Fe from hydrothermal venting to the oceans. Our study combined measurements of plume-height Fe concentrations from a series of 6 CTD stations together with studies of dissolved Fe speciation in a subset of those samples. At 2.5 km down plume from the nearest known vent site dissolved Fe concentrations were ˜ 20 nM. This is much higher than would be predicted from a combination of plume dilution and dissolved Fe(II) oxidation rates, but consistent with stabilisation due to the presence of organic Fe complexes and Fe colloids. Using Competitive Ligand Exchange-Cathodic Stripping Voltammetry (CLE-CSV), stabilised dissolved Fe complexes were detected within the dissolved Fe fraction on the edges of one non-buoyant hydrothermal plume with observed ligand concentrations high enough to account for stabilisation of ˜ 4% of the total Fe emitted from the 5° S vent sites. If these results were representative of all hydrothermal systems, submarine venting could provide 12-22% of the global deep-ocean dissolved Fe budget.

Attenuated total reflection UV spectroscopy for simultaneous analysis of alkali, sulphide and dissolved lignin in pulping liquors

International Nuclear Information System (INIS)

Chai, X.S.; Zhu, J.Y.; Luo, Q.; Li, J.

2003-01-01

This study experimentally demonstrated attenuated total reflection (ATR) ultraviolet (UV) spectroscopy for rapid and simultaneous determination of the concentrations of hydroxide, sulphide and dissolved lignin in kraft pulping liquors. A multivariate partial least squares fitting procedure (using commercially available software) was employed to obtain the species concentrations from the measured absorption spectra of the pulping liquors. Good agreements between ATR-UV measured species concentrations and those obtained by reference methods (titration for hydroxide and sulphide and conventional UV absorption for dissolved lignin) were achieved. (author)

nduced hyperlipidemic rats. Methods: Column chromatographic fractionation of butanol fraction of total methanol extract of leaves of Bauhinia variegata (Linn. yields four sub-fractions (sub-fraction A-D. All sub-fractions tested for their anti-hyperlipidemic activity. Sub-fractions administered at a dose of 65 mg/kg (oral to the Triton WR-1339 induced hyperlipidemic rats and total cholesterol, triglycerides, HDL, LDL and VLDL

Directory of Open Access Journals (Sweden)

Deepak Kumar

2012-10-01

Full Text Available Objective: To investigate the effect and evaluation of Anti-hyperlipidemic activity guided subfraction isolated from total methanolic extract of Bauhinia variegata (Linn. leaves on Triton WR-1339 induced hyperlipidemic rats. Methods: Column chromatographic fractionation of butanol fraction of total methanol extract of leaves of Bauhinia variegata (Linn. yields four subfractions (sub-fraction A-D. All sub-fractions tested for their anti-hyperlipidemic activity. Subfractions administered at a dose of 65 mg/kg (oral to the Triton WR-1339 induced hyperlipidemic rats and total cholesterol, triglycerides, HDL, LDL and VLDL level in the blood were checked. Results: Sub-fraction D showed significant reduction (P<0.05 among four sub-fraction in comparison with standard drug fenofibrate. Conclusions: From the above study it could be concluded that butanol sub-fraction D of Bauhinia variegata (Linn. not only have resulted in significant reduction in cholesterol, triglyceride, LDL, VLDL level but also increases the HDL level at a reduced dose level.

Experimental study on total dissolved gas supersaturation in water

Directory of Open Access Journals (Sweden)

Lu Qu

2011-12-01

Full Text Available More and more high dams have been constructed and operated in China. The total dissolved gas (TDG supersaturation caused by dam discharge leads to gas bubble disease or even death of fish. Through a series of experiments, the conditions and requirements of supersaturated TDG generation were examined in this study. The results show that pressure (water depth, aeration, and bubble dissolution time are required for supersaturated TDG generation, and the air-water contact area and turbulence intensity are the main factors that affect the generation rate of supersaturated TDG. The TDG supersaturation levels can be reduced by discharging water to shallow shoals downstream of the dam or using negative pressure pipelines. Furthermore, the TDG supersaturation levels in stilling basins have no direct relationship with those in reservoirs. These results are of great importance for further research on the prediction of supersaturated TDG generation caused by dam discharge and aquatic protection.

Diagenetic fractionation of carbon isotopes in particulate and dissolved organic matter in sediments from Skan Bay, Alaska

International Nuclear Information System (INIS)

Alperin, M.J.; Reeburgh, W.S.

1991-01-01

Isotope fractionation during organic matter diagenesis was investigated by measuring detailed depth distributions of stable carbon isotope ratios in sediment particulate organic carbon (POC) and dissolved organic carbon (DOC) reservoirs. The δ 13 C value of the POC shifted systematically from -19 per-thousand at the surface to -21 per-thousand at 10 cm. Significant trends were also apparent in the δ 13 C-DOC profile. Proceeding down-core, DOC became isotopically heavier between 0 and 5 cm and isotopically lighter at greater depths. Two mechanisms could account for the observed down-core shift in δ 13 C-POC: (a) temporal changes in the isotope ratios of deposited organic matter and (b) isotope fractionation associated with diagenesis. The δ 15 C-DOC depth distribution is sensitive to which mechanism controls the isotopic composition of the POC reservoir. A diagenetic model that couples POC and DOC reservoirs was used to discriminate between temporal changes and diagenetic alteration of the POC isotopic composition. The model indicated that observed trends in δ 13 C-POC and δ 13 C-DOC depth distributions are consistent with isotopic fractionation of POC during diagenesis

Dissolved organic matter (DOM) in microalgal photobioreactors: a potential loss in solar energy conversion?

Science.gov (United States)

Hulatt, Chris J; Thomas, David N

2010-11-01

Microalgae are considered to be a potential alternative to terrestrial crops for bio-energy production due to their relatively high productivity per unit area of land. In this work we examined the amount of dissolved organic matter exuded by algal cells cultured in photobioreactors, to examine whether a significant fraction of the photoassimilated biomass could potentially be lost from the harvestable biomass. We found that the mean maximum amount of dissolved organic carbon (DOC) released measured 6.4% and 17.3% of the total organic carbon in cultures of Chlorellavulgaris and Dunaliella tertiolecta, respectively. This DOM in turn supported a significant growth of bacterial biomass, representing a further loss of the algal assimilated carbon. The release of these levels of DOC indicates that a significant fraction of the photosynthetically fixed organic matter could be lost into the surrounding water, suggesting that the actual biomass yield per hectare for industrial purposes could be somewhat less than expected. A simple and inexpensive optical technique, based on chromophoric dissolved organic matter (CDOM) measurements, to monitor such losses in commercial PBRs is discussed.

Response surface modeling for optimization heterocatalytic Fenton oxidation of persistence organic pollution in high total dissolved solid containing wastewater.

Science.gov (United States)

Sekaran, G; Karthikeyan, S; Boopathy, R; Maharaja, P; Gupta, V K; Anandan, C

2014-01-01

The rice-husk-based mesoporous activated carbon (MAC) used in this study was precarbonized and activated using phosphoric acid. N2 adsorption/desorption isotherm, X-ray powder diffraction, electron spin resonance, X-ray photoelectron spectroscopy and scanning electron microscopy, transmission electron microscopy, (29)Si-NMR spectroscopy, and diffuse reflectance spectroscopy were used to characterize the MAC. The tannery wastewater carrying high total dissolved solids (TDS) discharged from leather industry lacks biodegradability despite the presence of dissolved protein. This paper demonstrates the application of free electron-rich MAC as heterogeneous catalyst along with Fenton reagent for the oxidation of persistence organic compounds in high TDS wastewater. The heterogeneous Fenton oxidation of the pretreated wastewater at optimum pH (3.5), H2O2 (4 mmol/L), FeSO4[Symbol: see text]7H2O (0.2 mmol/L), and time (4 h) removed chemical oxygen demand, biochemical oxygen demand, total organic carbon and dissolved protein by 86, 91, 83, and 90%, respectively.

STELLAR AND TOTAL BARYON MASS FRACTIONS IN GROUPS AND CLUSTERS SINCE REDSHIFT 1

International Nuclear Information System (INIS)

Giodini, S.; Pierini, D.; Finoguenov, A.; Pratt, G. W.; Boehringer, H.; Leauthaud, A.; Guzzo, L.; Aussel, H.; Bolzonella, M.; Capak, P.; Elvis, M.; Hasinger, G.; Ilbert, O.; Kartaltepe, J. S.; Koekemoer, A. M.; Lilly, S. J.; Massey, R.; Rhodes, J.; Salvato, M.; McCracken, H. J.

2009-01-01

We investigate if the discrepancy between estimates of the total baryon mass fraction obtained from observations of the cosmic microwave background (CMB) and of galaxy groups/clusters persists when a large sample of groups is considered. To this purpose, 91 candidate X-ray groups/poor clusters at redshift 0.1 ≤ z ≤ 1 are selected from the COSMOS 2 deg 2 survey, based only on their X-ray luminosity and extent. This sample is complemented by 27 nearby clusters with a robust, analogous determination of the total and stellar mass inside R 500 . The total sample of 118 groups and clusters with z ≤ 1 spans a range in M 500 of ∼10 13 -10 15 M sun . We find that the stellar mass fraction associated with galaxies at R 500 decreases with increasing total mass as M -0.37±0.04 500 , independent of redshift. Estimating the total gas mass fraction from a recently derived, high-quality scaling relation, the total baryon mass fraction (f stars+gas 500 = f stars 500 + f gas 500 ) is found to increase by ∼25%, when M 500 increases from (M) = 5 x 10 13 M sun to (M) = 7 x 10 14 M sun . After consideration of a plausible contribution due to intracluster light (11%-22% of the total stellar mass) and gas depletion through the hierarchical assembly process (10% of the gas mass), the estimated values of the total baryon mass fraction are still lower than the latest CMB measure of the same quantity (WMAP5), at a significance level of 3.3σ for groups of (M) = 5 x 10 13 M sun . The discrepancy decreases toward higher total masses, such that it is 1σ at (M) = 7 x 10 14 M sun . We discuss this result in terms of nongravitational processes such as feedback and filamentary heating.

Human Milk MicroRNA and Total RNA Differ Depending on Milk Fractionation.

Science.gov (United States)

Alsaweed, Mohammed; Hepworth, Anna R; Lefèvre, Christophe; Hartmann, Peter E; Geddes, Donna T; Hassiotou, Foteini

2015-10-01

MicroRNA have been recently discovered in human milk signifying potentially important functions for both the lactating breast and the infant. Whilst human milk microRNA have started to be explored, little data exist on the evaluation of sample processing, and analysis to ensure that a full spectrum of microRNA can be obtained. Human milk comprises three main fractions: cells, skim milk, and lipids. Typically, the skim milk fraction has been measured in isolation despite evidence that the lipid fraction may contain more microRNA. This study aimed to standardize isolation of microRNA and total RNA from all three fractions of human milk to determine the most appropriate sampling and analysis procedure for future studies. Three different methods from eight commercially available kits were tested for their efficacy in extracting total RNA and microRNA from the lipid, skim, and cell fractions of human milk. Each fraction yielded different concentrations of RNA and microRNA, with the highest quantities found in the cell and lipid fractions, and the lowest in skim milk. The column-based phenol-free method was the most efficient extraction method for all three milk fractions. Two microRNAs were expressed and validated in the three milk fractions by qPCR using the three recommended extraction kits for each fraction. High expression levels were identified in the skim and lipid milk factions for these microRNAs. These results suggest that careful consideration of both the human milk sample preparation and extraction protocols should be made prior to embarking upon research in this area. © 2015 The Authors. Journal of Cellular Biochemistry Published by Wiley Periodicals, Inc.

Marrow toxicity of fractionated vs. single dose total body irradiation is identical in a canine model

International Nuclear Information System (INIS)

Storb, R.; Raff, R.F.; Graham, T.; Appelbaum, F.R.; Deeg, H.J.; Schuening, F.G.; Shulman, H.; Pepe, M.

1993-01-01

The authors explored in dogs the marrow toxicity of single dose total body irradiation delivered from two opposing 60 Co sources at a rate of 10 cGy/min and compared results to those seen with total body irradiation administered in 100 cGy fractions with minimum interfraction intervals of 6 hr. Dogs were not given marrow transplants. They found that 200 cGy single dose total body irradiation was sublethal, with 12 of 13 dogs showing hematopoietic recovery and survival. Seven of 21 dogs given 300 cGy single dose total body irradiation survived compared to 6 of 10 dogs given 300 cGy fractionated total body irradiation. One of 28 dogs given 400 cGy single dose total body irradiation survived compared to none of six given fractionated radiation. With granulocyte colony stimulating factor (GCSF) administered from day 0-21 after 400 cGy total body irradiation, most dogs survived with hematological recovery. Because of the almost uniform success with GCSF after 400 cGy single dose total body irradiation, a study of GCSF after 400 cGy fractionated total body irradiation was deemed not to be informative and, thus, not carried out. Additional comparisons between single dose and fractionated total body irradiation were carried out with GCSF administered after 500 and 600 cGy of total body irradiation. As with lower doses of total body irradiation, no significant survival differences were seen between the two modes of total body irradiation, and only 3 of 26 dogs studied survived with complete hematological recovery. Overall, therefore, survival among dogs given single dose total body irradiation was not different from that of dogs given fractionated total body irradiation (p = .67). Similarly, the slopes of the postirradiation declines of granulocyte and platelet counts and the rates of their recovery in surviving dogs given equal total doses of single versus fractionated total body irradiation were indistinguishable. 24 refs., 3 figs., 2 tabs

Development and application of the diffusive gradients in thin films technique for the measurement of total dissolved inorganic arsenic in waters

Energy Technology Data Exchange (ETDEWEB)

Panther, Jared G.; Stillwell, Kathryn P.; Powell, Kipton J. [Chemistry Department, University of Canterbury, Private Bag 4800, Christchurch (New Zealand); Downard, Alison J. [Chemistry Department, University of Canterbury, Private Bag 4800, Christchurch (New Zealand)], E-mail: alison.downard@canterbury.ac.nz

2008-08-01

The diffusive gradients in thin films (DGT) technique, utilizing an iron-hydroxide adsorbent, has been investigated for the in situ accumulation of total dissolved inorganic As in natural waters. Diffusion coefficients of the inorganic As{sup V} and As{sup III} species in the polyacrylamide gel were measured using a diffusion cell and DGT devices and a variety of factors that may affect the adsorption of the As species to the iron-hydroxide adsorbent, or the diffusion of the individual As species, were investigated. Under conditions commonly encountered in environmental samples, solution pH and the presence of anions, cations, fulvic acid, Fe{sup III}-fulvic acid complexes and colloidal iron-hydroxide were demonstrated not to affect uptake of dissolved As. To evaluate DGT as a method for accumulation and pre-concentration of total dissolved inorganic As in natural waters, DGT was applied to two well waters and a river water that was spiked with As. For each sample, the concentration obtained with use of DGT followed by measurement by hydride generation atomic absorption spectrometry with a Pd modifier (HG-AAS) was compared with the concentration of As measured directly by HG-AAS. The results confirmed that DGT is a reliable method for pre-concentration of total dissolved As.

Development and application of the diffusive gradients in thin films technique for the measurement of total dissolved inorganic arsenic in waters

International Nuclear Information System (INIS)

Panther, Jared G.; Stillwell, Kathryn P.; Powell, Kipton J.; Downard, Alison J.

2008-01-01

The diffusive gradients in thin films (DGT) technique, utilizing an iron-hydroxide adsorbent, has been investigated for the in situ accumulation of total dissolved inorganic As in natural waters. Diffusion coefficients of the inorganic As V and As III species in the polyacrylamide gel were measured using a diffusion cell and DGT devices and a variety of factors that may affect the adsorption of the As species to the iron-hydroxide adsorbent, or the diffusion of the individual As species, were investigated. Under conditions commonly encountered in environmental samples, solution pH and the presence of anions, cations, fulvic acid, Fe III -fulvic acid complexes and colloidal iron-hydroxide were demonstrated not to affect uptake of dissolved As. To evaluate DGT as a method for accumulation and pre-concentration of total dissolved inorganic As in natural waters, DGT was applied to two well waters and a river water that was spiked with As. For each sample, the concentration obtained with use of DGT followed by measurement by hydride generation atomic absorption spectrometry with a Pd modifier (HG-AAS) was compared with the concentration of As measured directly by HG-AAS. The results confirmed that DGT is a reliable method for pre-concentration of total dissolved As

Chromium Fractions Changes Compared With Total-Cr As Determined by Neutron Activation Analysis Technique

International Nuclear Information System (INIS)

Abdel-Sabour, M.F.; Abdou, F.M.; Elwan, I.M.; Al-Salama, Y.J.

2003-01-01

Fifteen soil samples were chosen from different locations (five different locations at north greater Cairo, Egypt to represent different soils (alluvial and sandy) as well as different source of contaminated wastewater (sewage and industrial effluent). Using sequential extraction technique (extracting the soil with different solutions, which is designed to separate metal fractions), Cr was separated into six operationally defined fractions water soluble, exchangeable, carbonate bound, Fe-Mn oxides bound, organic bound and residual fractions. Result of soil total-Cr indicated the serious accumulation of Cr in soils subjected to prolonged irrigation with contaminated wastewater. As it could seen, total-Cr in the tested contaminated soils exceeds the permissible levels (75-100)ppm Cr by several order of magnitude particularly at the surface and subsurface layers. The highest accumulation of total Cr down to depth 60 cm was observed in case of soil E. Data showed that values of total Cr determined by NAA method were always higher than the relevant values determined either by AAS or those calculated after the sequential extraction method. T-test analysis showed the significant difference between NAA and either AAS or sequential extraction methods. Although T-test analysis showed that were significant differences between total content in soils as determined by destructive (AAS or SUM) and non-destructive (NAA) analytical techniques however, strong liner relation between NAA and other tested methods was obtained. Chromium distribution between different extractants shows that the greatest amounts are found in the residual and Occluded in Fe and Mn-Oxides fractions followed by carbonate or organic fractions. In most cases the proportion of all tested Cr-forms has increased in contaminated soil layers with higher enrichment in organically bound Cr, occluded in Fe and Mn oxides, carbonate exchangeable and soluble fractions. Results indicate that soil properties have a

Total Phenol amd Flavonoid contents of Crude Extract and Fractions ...

African Journals Online (AJOL)

Phenolic compounds are numerous in plants and are essential part of human diet. Picralima nitida has been extensively used in African folk medicine especially in West Africa. The present study evaluated the total phenolic and flavonoid contents of the extract and fractions of Picralima nitida. The methanol extracts of P.

Factors influencing concentrations of dissolved gaseous mercury (DGM) and total mercury (TM) in an artificial reservoir

International Nuclear Information System (INIS)

Ahn, Myung-Chan; Kim, Bomchul; Holsen, Thomas M.; Yi, Seung-Muk; Han, Young-Ji

2010-01-01

The effects of various factors including turbidity, pH, DOC, temperature, and solar radiation on the concentrations of total mercury (TM) and dissolved gaseous mercury (DGM) were investigated in an artificial reservoir in Korea. Episodic total mercury accumulation events occurred during the rainy season as turbidity increased, indicating that the TM concentration was not controlled by direct atmospheric deposition. The DGM concentration in surface water ranged from 3.6 to 160 pg/L, having a maximum in summer and minimum in winter. While in most previous studies DGM was controlled primarily by a photo-reduction process, DGM concentrations tracked the amount of solar radiation only in winter when the water temperature was fairly low in this study. During the other seasons microbial transformation seemed to play an important role in reducing Hg(II) to Hg(0). DGM increased as dissolved organic carbon (DOC) concentration increased (p-value < 0.01) while it increased with a decrease of pH (p-value < 0.01). - Long-term in-situ monitoring of TM and DGM concentrations with various factors was executed in a large artificial reservoir in this study.

The size distribution of dissolved uranium in natural waters

International Nuclear Information System (INIS)

Mann, D.K.; Wong, G.T.F.

1987-01-01

The size distribution of dissolved uranium in natural waters is poorly known. Some fraction of dissolved uranium is known to associate with organic matter which had a wide range of molecular weights. The presence of inorganic colloidal uranium has not been reported. Ultrafiltration has been used to quantify the size distribution of a number of elements, such as dissolved organic carbon, selenium, and some trace metals, in both the organic and/or the inorganic forms. The authors have applied this technique to dissolved uranium and the data are reported here

Dose rate and dose fractionation studies in total body irradiation of dogs

International Nuclear Information System (INIS)

Kolb, H.J.; Netzel, B.; Schaffer, E.; Kolb, H.

1979-01-01

Total body irradiation (TBI) with 800-900 rads and allogeneic bone marrow transplantation according to the regimen designated by the Seattle group has induced remissions in patients with otherwise refractory acute leukemias. Relapse of leukemia after bone marrow transplantation remains the major problem, when the Seattle set up of two opposing 60 Co-sources and a low dose rate is used in TBI. Studies in dogs with TBI at various dose rates confirmed observations in mice that gastrointestinal toxicity is unlike toxicity against hemopoietic stem cells and possibly also leukemic stem cells depending on the dose rate. However, following very high single doses (2400 R) and marrow infusion acute gastrointestinal toxicity was not prevented by the lowest dose rate studied (0.5 R/min). Fractionated TBI with fractions of 600 R in addition to 1200 R (1000 rads) permitted the application of total doses up to 300 R followed by marrow infusion without irreversible toxicity. 26 dogs given 2400-3000 R have been observed for presently up to 2 years with regard to delayed radiation toxicity. This toxicity was mild in dogs given single doses at a low dose rate or fractionated TBI. Fractionated TBI is presently evaluated with allogeneic transplants in the dog before being applied to leukemic patients

THE SERUM PROTEIN FRACTIONS IN THYMOQUINONE TREATED RATS.

Science.gov (United States)

A, Güllü; S, Dede

2016-01-01

TQ has been used as treatment and preventive agent for many diseases over the years. The goal of this study was to investigate the effects of TQ supplement on fractions of serum proteins. Fourteen male Wistar-Albino rats (200-250 g weight) were used as material for two groups; (control (C) and thymoquinone (TQ) respectively. Each group contained seven rats. The control group had only corn oil, while the TQ group was dissolved in corn oil. 30 mg/kg/day were given by oral gavage for four weeks. The serum protein fractions were identified using cellulose acetate technique. The total protein level and albumin, α-1, α-2 fractions and A/G ratio have showed no difference between groups (p>0.05). β-globulin fractions of TQ group were higher than control's (pfractions may have originated from elevation or decline synthesis, or activities of containing proteins.

Chromophoric Dissolved Organic Matter in Southwestern Greenland Lakes

Science.gov (United States)

Osburn, C. L.; Giles, M. E.; Underwood, G. J. C.

2014-12-01

Dissolved organic matter (DOM) is an important property of Arctic lake ecosystems, originating from allochthonous inputs from catchments and autochthonous production by plankton in the water column. Little is known about the quality of DOM in Arctic lakes that lack substantial inputs from catchments and such lakes are abundant in southwestern Greenland. Colored dissolved organic matter (CDOM), the fraction that absorbs ultraviolet (UV) and visible light, is the controlling factor for the optical properties of many surface waters and as well informs on the quality of DOM. We examined the quality of CDOM in 21 lakes in southwestern Greenland, from the ice sheet to the coast, as part of a larger study examining the role of DOM in regulating microbial communities in these lakes. DOM was size fractioned and absorbance and fluorescence was measured on each size fraction, as well as on bulk DOM. The specific ultraviolet absorbance (SUVA) at 254 nm (SUVA254), computed by normalizing absorption (a254) to dissolved organic carbon (DOC) concentration, provided an estimate of the aromatic carbon content of DOM. SUVA values were generally CDOM fluorescence was used to determine the relative abundance of allochthonous and autochthonous DOM in all size fractions. Younger lakes near the ice sheet and lakes near the coast had lower amounts of CDOM and appeared more microbial in quality. However, lakes centrally located between the ice sheet and the coast had the highest CDOM concentrations and exhibited strong humic fluorescence. Overall distinct differences in CDOM quality were observed between lake locations and among DOM size fractions.

Dissolved organic nitrogen recalcitrance and bioavailable nitrogen quantification for effluents from advanced nitrogen removal wastewater treatment facilities.

Science.gov (United States)

Fan, Lu; Brett, Michael T; Jiang, Wenju; Li, Bo

2017-10-01

The objective of this study was to determine the composition of nitrogen (N) in the effluents of advanced N removal (ANR) wastewater treatment plants (WWTPs). This study also tested two different experimental protocols for determining dissolved N recalcitrance. An analysis of 15 effluent samples from five WWTPs, showed effluent concentrations and especially effluent composition varied greatly from one system to the other, with total nitrogen (TN) ranging between 1.05 and 8.10 mg L -1 . Nitrate (NO 3 - ) accounted for between 38 ± 32% of TN, and ammonium accounted for a further 29 ± 28%. All of these samples were dominated by dissolved inorganic nitrogen (DIN; NO 3 -  + NH 4 + ), and uptake experiments indicated the DIN fraction was as expected highly bioavailable. Dissolved organic N (DON) accounted for 20 ± 11% for the total dissolved N in these effluents, and uptake experiments indicated the bioavailability of this fraction varied between 27 ± 26% depending on the WWTP assessed. These results indicate near complete DIN removal should be the primary goal of ANR treatment systems. The comparison of bioavailable nitrogen (BAN) quantification protocols showed that the dissolved nitrogen uptake bioassay approach was clearly a more reliable way to determine BAN concentrations compared to the conventional cell yield protocol. Moreover, because the nitrogen uptake experiment was much more sensitive, this protocol made it easier to detect extrinsic factors (such as biological contamination or toxicity) that could affect the accuracy of these bioassays. Based on these results, we recommend the nitrogen uptake bioassay using filtered and autoclaved samples to quantify BAN concentrations. However, for effluent samples indicating toxicity, algal bioassays will not accurately quantify BAN. Copyright © 2017 Elsevier Ltd. All rights reserved.

Isotope-geochemical studies on fractions of dissolved organic carbon (DOC) for determining the origin and evolution of DOC for purposes of groundwater dating

International Nuclear Information System (INIS)

Geyer, S.

1994-01-01

The laboratory work consisted in developing and testing methods of extraction and enrichment of individual high-purity DOC fractions (fulvic acids, humic acids, and low-molecular substances) with the aim of preparing large quantities of groundwaters (> 1000 l) with low DOC concentrations so as to obtain sufficient sampling material. Chemical characterisation of DOC consisted in an analysis of humic and fulvic acids with regard to element composition (C, H, N, O, S) and inorganic trace elements. Isotopic characterization of the DOC fractions consisted in determining 14 C, 13 C, and 2 H levels. For the first time δ 34 S and δ 15 N relations in humic and fulvic acids dissolved in groundwater were determined. (orig./DG) [de

Immunosuppression by fractionated total lymphoid irradiation in collagen arthritis

International Nuclear Information System (INIS)

McCune, W.J.; Buckley, J.A.; Belli, J.A.; Trentham, D.E.

1982-01-01

Treatments with fractionated total lymphoid irradiation (TLI) and cyclophosphamide were evaluated for rats injected with type II collagen. Preadministration of TLI and repeated injections of cyclophosphamide suppressed the severity of arthritis and lowered antibody titers to collagen significantly. TLI initiated at the onset of collagen arthritis decreased humoral and cellular responses to collagen but did not affect the severity of arthritis. These data demonstrate that both TLi and cyclophosphamide are immunosuppressive in an experimentally inducible autoimmune disease

Characteristics of phosphorus fractionated from the sediment resuspension in abrupt expansion flow experiments

Institute of Scientific and Technical Information of China (English)

Jun Wan; Ze Wang; Hezhong Yuan

2010-01-01

Phosphorous (P) fraction characteristics in sediment resuspension were investigated under adequately hydrodynamic conditions.Four forms of P in overlying water,including dissolved inorganic P,dissolved total P,total P,and particulate P,and six fractions of P in suspended particulate matter (SPM),including loosely sorbed P (NH4Cl-P),redox-sensitive P (BD-P),aluminum-bound P (Al-P),organic P (NaOH-nrP),calcium-bound P (Ca-P) and residual P (Res-P),were quantified,respectively.Different hydrodynamic conditions resulted in different P form changes.Four states could be ascribed:(1) P desorption by sediment and SPM,and P adsorption by overlying water;(2) P desorption by SPM,and P adsorption by overlying water;(3) P adsorption by SPM,and P desorption by overlying water;and (4) P equilibrium between SPM and overlying water.The contents of P in overlying water acquired peak values in the middle position of the vertical P distribution due to the combined actions of SPM and sediment.P fractions in SPM were in the following order:BD-P＞NaOH-nrp＞Ca-P＞Al-P＞Res-P＞NH4CI-P.BD-P in SPM frequently exchanged with P forms in overlying water.Resuspension was favorable to forming Ca-P in SPM.

Absorption features of chromophoric dissolved organic matter (CDOM) and tracing implication for dissolved organic carbon (DOC) in Changjiang Estuary, China

OpenAIRE

Zhang, X. Y.; Chen, X.; Deng, H.; Du, Y.; Jin, H. Y.

2013-01-01

Chromophoric dissolved organic matter (CDOM) represents the light absorbing fraction of dissolved organic carbon (DOC). Studies have shown that the optical properties of CDOM can be used to infer the distribution and diffusion characteristics of DOC in the estuary and coastal zone. The inversion of DOC concentrations from remote sensing has been implemented in certain regions. In this study we investigate the potential of tracing DOC from CDOM by the measure...

Application of isotope dilution method for measuring bioavailability of organic contaminants sorbed to dissolved organic matter (DOM)

Energy Technology Data Exchange (ETDEWEB)

Delgado-Moreno, Laura, E-mail: laura.delgado@eez.csic.es; Wu, Laosheng; Gan, Jay

2015-08-15

Natural waters such as surface water and sediment porewater invariably contain dissolved organic matter (DOM). Association of strongly hydrophobic contaminants (HOCs) with DOM leads to decreased toxicity and bioavailability, but bioavailability of DOM-sorbed HOCs is difficult to measure. Current methods to estimate bioavailability of HOCs in water are based on only the freely dissolved concentration (C{sub free}). The ignorance of the exchangeable fraction of HOCs sorbed on DOM may result in an underestimation of the toxicity potential of HOCs to aquatic organisms. Here we explore the applicability of an isotope dilution method (IDM) to measuring the desorption fraction of DOM-sorbed pyrene and bifenthrin and determining their exchangeable pool (E) as an approximation of bioavailability. E values, expressed as percentage of the total concentration, ranged between 0.80 and 0.92% for pyrene and 0.74 and 0.85% for bifenthrin, depending primarily on the amount of chemical in the freely dissolved form. However, between 34 and 78% of the DOM-sorbed pyrene was exchangeable. This fraction ranged between 23% and 82% for bifenthrin. The ability of IDM to predict bioavailability was further shown from a significant relationship (r{sup 2} > 0.72, P < 0.0001) between E and bioaccumulation into Daphnia magna. Therefore, IDM may be used to improve the bioavailability measurement and risk assessment of HOCs in aquatic systems.

Application of isotope dilution method for measuring bioavailability of organic contaminants sorbed to dissolved organic matter (DOM)

International Nuclear Information System (INIS)

Delgado-Moreno, Laura; Wu, Laosheng; Gan, Jay

2015-01-01

Natural waters such as surface water and sediment porewater invariably contain dissolved organic matter (DOM). Association of strongly hydrophobic contaminants (HOCs) with DOM leads to decreased toxicity and bioavailability, but bioavailability of DOM-sorbed HOCs is difficult to measure. Current methods to estimate bioavailability of HOCs in water are based on only the freely dissolved concentration (C free ). The ignorance of the exchangeable fraction of HOCs sorbed on DOM may result in an underestimation of the toxicity potential of HOCs to aquatic organisms. Here we explore the applicability of an isotope dilution method (IDM) to measuring the desorption fraction of DOM-sorbed pyrene and bifenthrin and determining their exchangeable pool (E) as an approximation of bioavailability. E values, expressed as percentage of the total concentration, ranged between 0.80 and 0.92% for pyrene and 0.74 and 0.85% for bifenthrin, depending primarily on the amount of chemical in the freely dissolved form. However, between 34 and 78% of the DOM-sorbed pyrene was exchangeable. This fraction ranged between 23% and 82% for bifenthrin. The ability of IDM to predict bioavailability was further shown from a significant relationship (r 2 > 0.72, P < 0.0001) between E and bioaccumulation into Daphnia magna. Therefore, IDM may be used to improve the bioavailability measurement and risk assessment of HOCs in aquatic systems

Contribution of radioactive 137Cs discharge by suspended sediment, coarse organic matter, and dissolved fraction from a headwater catchment in Fukushima after the Fukushima Dai-ichi Nuclear Power Plant accident.

Science.gov (United States)

Iwagami, Sho; Onda, Yuichi; Tsujimura, Maki; Abe, Yutaka

2017-01-01

Radiocesium ( 137 Cs) migration from headwaters in forested areas provides important information, as the output from forest streams subsequently enters various land-use areas and downstream rivers. Thus, it is important to determine the composition of 137 Cs fluxes (dissolved fraction, suspended sediment, or coarse organic matter) that migrate through a headwater stream. In this study, the 137 Cs discharge by suspended sediment and coarse organic matter from a forest headwater catchment was monitored. The 137 Cs concentrations in suspended sediment and coarse organic matter, such as leaves and branches, and the amounts of suspended sediment and coarse organic matter were measured at stream sites in three headwater catchments in Yamakiya District, located ∼35 km northwest of Fukushima Dai-ichi Nuclear Power Plant (FDNPP) from August 2012 to September 2013, following the earthquake and tsunami disaster. Suspended sediment and coarse organic matter were sampled at intervals of approximately 1-2 months. The 137 Cs concentrations of suspended sediment and coarse organic matter were 2.4-49 kBq/kg and 0.85-14 kBq/kg, respectively. The 137 Cs concentrations of the suspended sediment were closely correlated with the average deposition density of the catchment. The annual proportions of contribution of 137 Cs discharge by suspended sediment, coarse organic matter, and dissolved fraction were 96-99%, 0.0092-0.069%, and 0.73-3.7%, respectively. The total annual 137 Cs discharge from the catchment was 0.02-0.3% of the deposition. Copyright © 2016 Elsevier Ltd. All rights reserved.

Laboratory studies of dissolved radiolabelled microcystin-LR in lake water

DEFF Research Database (Denmark)

Hyenstrand, Per; Rohrlack, Thomas; Beattie, Kenneth A

2003-01-01

The fate of dissolved microcystin-LR was studied in laboratory experiments using surface water taken from a eutrophic lake. Based on initial range finding, a concentration of 50 microg l(-1) dissolved 14C-microcystin-LR was selected for subsequent time-course experiments. The first was performed ...... fractions. The study demonstrated that biodegradation of dissolved microcystin-LR occurred in water collected at a lake surface with carbon dioxide as a major end-product....

Relationships between colored dissolved organic matter and dissolved organic carbon in different coastal gradients of the Baltic Sea

OpenAIRE

Harvey, E. Therese; Kratzer, Susanne; Andersson, Agneta

2015-01-01

Due to high terrestrial runoff, the Baltic Sea is rich in dissolved organic carbon (DOC), the light-absorbing fraction of which is referred to as colored dissolved organic matter (CDOM). Inputs of DOC and CDOM are predicted to increase with climate change, affecting coastal ecosystems. We found that the relationships between DOC, CDOM, salinity, and Secchi depth all differed between the two coastal areas studied; the W Gulf of Bothnia with high terrestrial input and the NW Baltic Proper with ...

Acid-base properties of Baltic Sea dissolved organic matter

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Hammer, Karoline; Schneider, Bernd; Kuliński, Karol; Schulz-Bull, Detlef E.

2017-09-01

Calculations related to the marine CO2 system that are based on alkalinity data may be strongly biased if the contributions of organic compounds are ignored. In coastal seas, concentrations of dissolved organic matter (DOM) are frequently high and alkalinity from inorganic compounds is low. In this study, based on measurements of total alkalinity, total CO2, and pH, we determined the organic alkalinity, Aorg, in water from the central Baltic Sea. The maximum Aorg measured in the surface mixed layer during the spring bloom was > 50 μmol/kg-SW but the Aorg decreased with depth and approached zero below the permanent halocline. This behavior could be attributed to the decreased pH of deeper water layers. The data were used to calculate the bulk dissociation constant, KDOM, for marine DOM and the fraction f of dissolved organic carbon (DOC) that acts as a carrier for acid-base functional groups. The p KDOM (7.27) agreed well with the value (7.34) previously estimated in a preliminary study of organic alkalinity in the Baltic Sea. The fraction of carbon atoms carrying acid-base groups was 17% and was somewhat higher than previously reported (12%). Spike experiments performed using artificial seawater and three different humic/fulvic substances tested whether the acid-base properties of these substances explain the results of our field study. Specifically, Aorg was determined at different concentrations (DOC) of the added humic/fulvic substances. The relationship between Aorg and the DOC concentrations indicated that humic/fulvic substances are more acidic (p KDOM < 6.5) than the bulk DOC natural occurring in the Baltic Sea.

Bench-Scale and Pilot-Scale Treatment Technologies for the Removal of Total Dissolved Solids from Coal Mine Water: A Review

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Coal mine water (CMW) is typically treated to remove suspended solids, acidity, and soluble metals, but high concentrations of total dissolved solids (TDS) have been reported to impact the environment at several CMW discharge points. Consequently, various states have establishe...

Spatiotemporal variation characteristics and related affecting factors of dissolved carbohydrates in the East China Sea

Science.gov (United States)

He, Zhen; Wang, Qi; Yang, Gui-Peng; Gao, Xian-Chi; Wu, Guan-Wei

2015-10-01

Carbohydrates are the largest identified fraction of dissolved organic carbon and play an important role in biogeochemical cycling in the ocean. Seawater samples were collected from the East China Sea (ECS) during June and October 2012 to study the spatiotemporal distributions of total dissolved carbohydrates (TCHOs) constituents, including dissolved monosaccharides (MCHOs) and polysaccharides (PCHOs). The concentrations of TCHOs, MCHOs and PCHOs showed significant differences between summer and autumn 2012, and exhibited an evident diurnal variation, with high values occurring in the daytime. Phytoplankton biomass was identified as the primary factor responsible for seasonal and diurnal variations of dissolved carbohydrates in the ECS. The TCHOs, MCHOs and PCHOs distributions in the study area displayed similar distribution patterns, with high concentrations appearing in the coastal water. The influences of chlorophyll-a, salinity and nutrients on the distributions of these carbohydrates were examined. A carbohydrate enrichment in the near-bottom water was found at some stations, implying that there might be an important source of carbohydrate in the deep water or bottom sediment.

Ground-fire effects on the composition of dissolved and total organic matter in forest floor and soil solutions from Scots pine forests in Germany: new insights from solid state 13C NMR analysis

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Näthe, Kerstin; Michalzik, Beate; Levia, Delphis; Steffens, Markus

2016-04-01

Fires represent an ecosystem disturbance and are recognized to seriously pertubate the nutrient budgets of forested ecosystems. While the effects of fires on chemical, biological, and physical soil properties have been intensively studied, especially in Mediterranean areas and North America, few investigations examined the effects of fire-induced alterations in the water-bound fluxes and the chemical composition of dissolved and particulate organic carbon and nitrogen (DOC, POC, DN, PN). The exclusion of the particulate organic matter fraction (0.45 μm Independent from fire manipulation, the composition of TOM was generally less aromatic (aromaticity index [%] according to Hatcher et al., 1981) with values between 18 (FF) - 25% (B horizon) than the DOM fraction with 23 (FF) - 27% (B horizon). For DOM in FF solution, fire manipulation caused an increase in aromaticity from 23 to 27% compared to the control, due to an increase of the aryl-C and a decrease of the O-alkyl-C and alkyl-C signal. Fire effects were leveled out in the mineral soil. For TOM, fire effects became notable only in the A horizon, exhibiting a decrease in aromaticity from 22 to 18% compared to the control, due to increased O-alkyl-C and diminished aryl-C proportions. Compared to the control, fire only caused minor DOC release rates (events did not significantly enhance the proportion of POC and PN in the total C and N amounts exhibiting values between 10 and 20%. To fully understand the quality and amount of translocated organic C and N compounds within soils under both ambient as well as fire environments, dissolved and particulate size fractions need to be considered.

Tidally driven export of dissolved organic carbon, total mercury, and methylmercury from a mangrove-dominated estuary

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Bergamaschi, B.A.; Krabbenhoft, D.P.; Aiken, G.R.; Patino, E.; Rumbold, D.G.; Orem, W.H.

2012-01-01

The flux of dissolved organic carbon (DOC) from mangrove swamps accounts for 10% of the global terrestrial flux of DOC to coastal oceans. Recent findings of high concentrations of mercury (Hg) and methylmercury (MeHg) in mangroves, in conjunction with the common co-occurrence of DOC and Hg species, have raised concerns that mercury fluxes may also be large. We used a novel approach to estimate export of DOC, Hg, and MeHg to coastal waters from a mangrove-dominated estuary in Everglades National Park (Florida, USA). Using in situ measurements of fluorescent dissolved organic matter as a proxy for DOC, filtered total Hg, and filtered MeHg, we estimated the DOC yield to be 180 (??12.6) g C m -2 yr -1, which is in the range of previously reported values. Although Hg and MeHg yields from tidal mangrove swamps have not been previously measured, our estimated yields of Hg species (28 ?? 4.5 ??g total Hg m -2 yr -1 and 3.1 ?? 0.4 ??g methyl Hg m -2 yr -1) were five times greater than is typically reported for terrestrial wetlands. These results indicate that in addition to the well documented contributions of DOC, tidally driven export from mangroves represents a significant potential source of Hg and MeHg to nearby coastal waters. ?? 2011 American Chemical Society.

Relationships between Personal Measurements of 'Total' Dust, Respirable, Thoracic, and Inhalable Aerosol Fractions in the Cement Production Industry.

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Notø, Hilde P; Nordby, Karl-Christian; Eduard, Wijnand

2016-05-01

The aims of this study were to examine the relationships and establish conversion factors between 'total' dust, respirable, thoracic, and inhalable aerosol fractions measured by parallel personal sampling on workers from the production departments of cement plants. 'Total' dust in this study refers to aerosol sampled by the closed face 37-mm Millipore filter cassette. Side-by-side personal measurements of 'total' dust and respirable, thoracic, and inhalable aerosol fractions were performed on workers in 17 European and Turkish cement plants. Simple linear and mixed model regressions were used to model the associations between the samplers. The total number of personal samples collected on 141 workers was 512. Of these 8.4% were excluded leaving 469 for statistical analysis. The different aerosol fractions contained from 90 to 130 measurements and-side-by side measurements of all four aerosol fractions were collected on 72 workers.The median ratios between observed results of the respirable, 'total' dust, and inhalable fractions relative to the thoracic aerosol fractions were 0.51, 2.4, and 5.9 respectively. The ratios between the samplers were not constant over the measured concentration range and were best described by regression models. Job type, position of samplers on left or right shoulder and plant had no substantial effect on the ratios. The ratios between aerosol fractions changed with different air concentrations. Conversion models for estimation of the fractions were established. These models explained a high proportion of the variance (74-91%) indicating that they are useful for the estimation of concentrations based on measurements of a different aerosol fraction. The calculated uncertainties at most observed concentrations were below 30% which is acceptable for comparison with limit values (EN 482, 2012). The cement industry will therefore be able to predict the health related aerosol fractions from their former or future measurements of one of the

Ultraviolet-B radiation mobilizes uranium from uranium-dissolved organic carbon complexes in aquatic systems, demonstrated by asymmetrical flow field-flow fractionation.

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Nehete, Sachin Vilas; Christensen, Terje; Salbu, Brit; Teien, Hans-Christian

2017-05-05

Humic substances have a tendency to form complexes with metal ions in aquatic medium, impacting the metal mobility, decreasing bioavailability and toxicity. Ultraviolet-B (UV-B) radiation exposure degrades the humic substance, changes their molecular weight distribution and their metal binding capacity in aquatic medium. In this study, we experimented the effect of UV-B radiation on the uranium complexed with fulvic acids and humic acids in a soft water system at different pH, uranium concentrations and radiant exposure. The concentration and distribution of uranium in a complexed form were investigated by asymmetrical flow field-flow fractionation coupled to multi detection technique (AsFlFFF-UV-ICP-MS). The major concentration of uranium present in complexes was primarily associated with average and higher molecular weight fulvic and humic acids components. The concentration of uranium in a complexed form increased with increasing fulvic and humic acid concentrations as well as pH of the solution. The higher molecular weight fraction of uranium was degraded due to the UV-B exposure, transforming about 50% of the uranium-dissolved organic carbon complexes into low molecular weight uranium species in complex form with organic ligands and/or free form. The result also suggests AsFlFFF-UV-ICP-MS to be an important separation and detection technique for understanding the interaction of radionuclides with dissolved organic matter, tracking size distribution changes during degradation of organic complexes for understanding mobility, bioavailability and ecosystem transfer of radionuclides as well as metals. Copyright © 2017 Elsevier B.V. All rights reserved.

Characterization of the dissolved organic carbon in landfill leachate-polluted groundwater

DEFF Research Database (Denmark)

Christensen, Jette B.; Jensen, Dorthe Lærke; Grøn, Christian

1998-01-01

Samples of dissolved organic carbon (DOG) were obtained from landfill leachate-polluted groundwater at Vejen Landfill, Denmark. The humic acids, fulvic acids and the hydrophilic fraction were isolated and purified. Based on DOC measurements, the fulvic acid fraction predominated, accounting...

Fractionated total body irradiation; the gastrointestinal toxicity versus the conditioning effect for bone marrow transplantation with different fractionation schedules

International Nuclear Information System (INIS)

Walma, E.P.; Klapwijk, W.M.; Miller, A.M.

1982-01-01

In most cases, bone marrow transplantation is preceded by a conditioning regimen employing irradiation and/or cytotoxic drugs. The authors are searching for better fractionation schedules in order to optimize the conditioning regimen prior to transplantation of stem-cell-enriched bone marrow. They have determined damage to the gastrointestinal tract in dogs and mice after total body irradiation in mice and dogs following a number of fractionation schedules, and these results are presented. The schedules were chosen such as to minimize the interval between irradiation and the bone marrow transplantation and to maximize clinical feasibility. (Auth./C.F.)

Radiocarbon (14C) Constraints On The Fraction Of Refractory Dissolved Organic Carbon In Primary Marine Aerosol From The Northwest Atlantic

Science.gov (United States)

Beaupre, S. R.; Kieber, D. J.; Keene, W. C.; Long, M. S.; Frossard, A. A.; Kinsey, J. D.; Duplessis, P.; Chang, R.; Maben, J. R.; Lu, X.; Zhu, Y.; Bisgrove, J.

2017-12-01

Nearly all organic carbon in seawater is dissolved (DOC), with more than 95% considered refractory based on modeled average lifetimes ( 16,000 years) and characteristically old bulk radiocarbon (14C) ages (4000 - 6000 years) that exceed the timescales of overturning circulation. Although this refractory dissolved organic carbon (RDOC) is present throughout the oceans as a major reservoir of the global carbon cycle, its sources and sinks are poorly constrained. Recently, RDOC was proposed to be removed from the oceans through adsorption onto the surfaces of rising bubble plumes produced by breaking waves, ejection into the atmosphere via bubble bursting as a component of primary marine aerosol (PMA), and subsequent oxidation in the atmosphere. To test this mechanism, we used natural abundance 14C (5730 ± 40 yr half-life) to trace the fraction of RDOC in PMA produced in a high capacity generator at two biologically-productive and two oligotrophic hydrographic stations in the Northwest Atlantic Ocean during a research cruise aboard the R/V Endeavor (Sep - Oct 2016). The 14C signatures of PMA separately generated day and night from near-surface (5 m) and deep (2500 m) seawater were compared with corresponding 14C signatures in seawater of near-surface dissolved inorganic carbon (DIC, a proxy for recently produced organic matter), bulk deep DOC (a proxy for RDOC), and near-surface bulk DOC. Results constrain the selectivity of PMA formation from RDOC in natural mixtures of recently produced and refractory DOC. The implications of these results for PMA formation and RDOC biogeochemistry will be discussed.

In vitro assessment of relief to oxidative stress by different fractions of Boerhavia procumbens.

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Abbasi, Muhammad Athar; Rubab, Kaniz; Rehman, Azizur; Riaz, Tauheeda; Shahzadi, Tayyaba; Khalid, Muniba; Ajaib, Muhammad

2012-04-01

Methanolic extract of Boerhavia procumbens Bank ex Roxb. was partitioned with n-hexane, chloroform, ethyl acetate and n-butanol sequentially after dissolving in distilled water. Phytochemical screening showed presence of phenolics, flavonoides and cardiac glycosides in large amount in chloroform, ethyl acetate and n-butanol soluble fraction. The antioxidant activity of all these fractions and the remaining aqueous fraction was evaluated by four methods such as: 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity, ferric reducing antioxidant power (FRAP) assay, total antioxidant activity and ferric thiocyanate assay. Total phenolics were also determined. Some fractions showed noteworthy antioxidant activity. The results of the antioxidant activity revealed that the ethyl acetate soluble fraction showed the highest value of percent inhibition of DPPH (82.54 ± 0.62) at the concentration of 125 μ g/ml. The IC(50) of this fraction was 37.11± 0.23 μg/ml, compared with butylated hydroxytoluene (BHT), which have IC(50) of 12.1 ± 0.92 μ/mL. It also showed the highest FRAP value (251.08 ± 1.46 μg of trolox equivalents) as well as the highest value of lipid peroxidation inhibition (57.21 ± 52%), the highest total antioxidant activity (0.549 ± 0.08) and also the highest total phenolic contents (77.1 ± 0.6) as compared to the studied fractions. Phytochemical screening showed high percentage of phenolics, flavonoides and cardiac glycosides in this fraction.

Determination of the partition coefficient between dissolved organic carbon and seawater using differential equilibrium kinetics.

Science.gov (United States)

Kim, Du Yung; Kwon, Jung-Hwan

2018-05-04

Because the freely dissolved fraction of highly hydrophobic organic chemicals is bioavailable, knowing the partition coefficient between dissolved organic carbon and water (K DOCw ) is crucial to estimate the freely dissolved fraction from the total concentration. A kinetic method was developed to obtain K DOCw that required a shorter experimental time than equilibrium methods. The equilibrium partition coefficients of four polychlorinated biphenyls (PCBs) (2,4,4'-trichlorobiphenyl (PCB 28), 2,2',3,5'-tetrachlorobiphenyl (PCB 44), 2,2',4,5,5'-pentachlorobiphenyl (PCB 101), and 2,2',4,4',5,5'-hexachlorobiphenyl (PCB 153)) between dissolved organic carbon and seawater (K DOCsw ) were determined using seawater samples from the Korean coast. The log K DOCsw values of PCB 28 were measured by equilibrating PCB 28, the least hydrophobic congener, with seawater samples, and the values ranged from 6.60 to 7.20. For the more hydrophobic PCBs (PCB 44, PCB 101, and PCB 153), kinetic experiments were conducted to determine the sorption rate constants (k 2 ) and their log K DOCsw values were obtained by comparing their k 2 with that of PCB 28. The calculated log K DOCsw values were 6.57-7.35 for PCB 44, 6.23-7.44 for PCB 101, and 6.35-7.73 for PCB 153. The validity of the proposed method was further confirmed using three less hydrophobic polycyclic aromatic hydrocarbons. This kinetic method shortened the experimental time to obtain the K DOCsw values of the more hydrophobic PCBs, which did not reach phase equilibrium. Copyright © 2018 Elsevier Ltd. All rights reserved.

Selective elimination of chromophoric and fluorescent dissolved organic matter in a full-scale municipal wastewater treatment plant.

Science.gov (United States)

Yang, Xiaofang; Zhou, Zhongbo; Raju, Maddela Naga; Cai, Xiaoxuan; Meng, Fangang

2017-07-01

Effluent organic matter (EfOM) from municipal wastewater treatment plants potentially has a detrimental effect on both aquatic organisms and humans. This study evaluated the removal and transformation of chromophoric dissolved organic matter (CDOM) and fluorescent dissolved organic matter (FDOM) in a full-scale wastewater treatment plant under different seasons. The results showed that bio-treatment was found to be more efficient in removing bulk DOM (in term of dissolved organic carbon, DOC) than CDOM and FDOM, which was contrary to the disinfection process. CDOM and FDOM were selectively removed at various stages during the treatment. Typically, the low molecular weight fractions of CDOM and protein-like FDOM were more efficiently removed during bio-treatment process, whereas the humic-like FDOM exhibited comparable decreases in both bio-treatment and disinfection processes. Overall, the performance of the WWTP was weak in terms of CDOM and FDOM removal, resulting in enrichment of CDOM and FDOM in effluent. Moreover, the total removal of the bulk DOM (PCDOM and the humic-like FDOM showed little differences between summer and winter. In all, the results provide useful information for understanding the fate and transformation of DOM, illustrating that sub-fractions of DOM could be selectively removed depending on treatment processes and seasonality. Copyright © 2016. Published by Elsevier B.V.

An In Silico Approach for Evaluating a Fraction-Based, Risk Assessment Method for Total Petroleum Hydrocarbon Mixtures

Directory of Open Access Journals (Sweden)

Nina Ching Y. Wang

2012-01-01

Full Text Available Both the Massachusetts Department of Environmental Protection (MADEP and the Total Petroleum Hydrocarbon Criteria Working Group (TPHCWG developed fraction-based approaches for assessing human health risks posed by total petroleum hydrocarbon (TPH mixtures in the environment. Both organizations defined TPH fractions based on their expected environmental fate and by analytical chemical methods. They derived toxicity values for selected compounds within each fraction and used these as surrogates to assess hazard or risk of exposure to the whole fractions. Membership in a TPH fraction is generally defined by the number of carbon atoms in a compound and by a compound's equivalent carbon (EC number index, which can predict its environmental fate. Here, we systematically and objectively re-evaluate the assignment of TPH to specific fractions using comparative molecular field analysis and hierarchical clustering. The approach is transparent and reproducible, reducing inherent reliance on judgment when toxicity information is limited. Our evaluation of membership in these fractions is highly consistent (̃80% on average across various fractions with the empirical approach of MADEP and TPHCWG. Furthermore, the results support the general methodology of mixture risk assessment to assess both cancer and noncancer risk values after the application of fractionation.

Forecasting models for flow and total dissolved solids in Karoun river-Iran

Science.gov (United States)

Salmani, Mohammad Hassan; Salmani Jajaei, Efat

2016-04-01

Water quality is one of the most important factors contributing to a healthy life. From the water quality management point of view, TDS (total dissolved solids) is the most important factor and many water developing plans have been implemented in recognition of this factor. However, these plans have not been perfect and very successful in overcoming the poor water quality problem, so there are a good volume of related studies in the literature. We study TDS and the water flow of the Karoun river in southwest Iran. We collected the necessary time series data from the Harmaleh station located in the river. We present two Univariate Seasonal Autoregressive Integrated Movement Average (ARIMA) models to forecast TDS and water flow in this river. Then, we build up a Transfer Function (TF) model to formulate the TDS as a function of water flow volume. A performance comparison between the Seasonal ARIMA and the TF models are presented.

Antidepressant effects of total tertiary alkaloid fraction of Cissampelos sympodialis Eichler in rodents

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Sueli Mendonça-Netto

Full Text Available The purpose of the present study was to evaluate the effects of total tertiary alkaloid fraction (TTAF of Cissampelos sympodialis Eichler (Menispermaceae on two animal models of depression: a forced swim test and b reserpine test. Treatment of mice with TTAF (12.5 mg/kg reduced the total immobility time. It also reversed the reserpine-induced hypothermia, demonstrating an antidepressant effect in both models. Additionally, TTAF treatment did not modify the ambulation and rearing evaluated in open field test in order to investigate if the immobility time reduction found in the forced swimming test was caused by locomotive activity stimulation. Since warifteine is one of the main alkaloids present in the TTAF of C. sympodialis, and it has inhibitory activity of the phosphodiesterase enzyme, it may be responsible by the antidepressant effect found in the fraction studied.

Characterization of Urban Runoff Pollution between Dissolved and Particulate Phases

Science.gov (United States)

Wei, Zhang; Simin, Li; Fengbing, Tang

2013-01-01

To develop urban stormwater management effectively, characterization of urban runoff pollution between dissolved and particulate phases was studied by 12 rainfall events monitored for five typical urban catchments. The average event mean concentration (AEMC) of runoff pollutants in different phases was evaluated. The AEMC values of runoff pollutants in different phases from urban roads were higher than the ones from urban roofs. The proportions of total dissolved solids, total dissolved nitrogen, and total dissolved phosphorus in total ones for all the catchments were 26.19%–30.91%, 83.29%–90.51%, and 61.54–68.09%, respectively. During rainfall events, the pollutant concentration at the initial stage of rainfall was high and then sharply decreased to a low value. Affected by catchments characterization and rainfall distribution, the highest concentration of road pollutants might appear in the later period of rainfall. Strong correlations were also found among runoffs pollutants in different phases. Total suspended solid could be considered as a surrogate for particulate matters in both road and roof runoff, while dissolved chemical oxygen demand could be regarded as a surrogate for dissolved matters in roof runoff. PMID:23935444

Characterization of urban runoff pollution between dissolved and particulate phases.

Science.gov (United States)

Wei, Zhang; Simin, Li; Fengbing, Tang

2013-01-01

To develop urban stormwater management effectively, characterization of urban runoff pollution between dissolved and particulate phases was studied by 12 rainfall events monitored for five typical urban catchments. The average event mean concentration (AEMC) of runoff pollutants in different phases was evaluated. The AEMC values of runoff pollutants in different phases from urban roads were higher than the ones from urban roofs. The proportions of total dissolved solids, total dissolved nitrogen, and total dissolved phosphorus in total ones for all the catchments were 26.19%-30.91%, 83.29%-90.51%, and 61.54-68.09%, respectively. During rainfall events, the pollutant concentration at the initial stage of rainfall was high and then sharply decreased to a low value. Affected by catchments characterization and rainfall distribution, the highest concentration of road pollutants might appear in the later period of rainfall. Strong correlations were also found among runoffs pollutants in different phases. Total suspended solid could be considered as a surrogate for particulate matters in both road and roof runoff, while dissolved chemical oxygen demand could be regarded as a surrogate for dissolved matters in roof runoff.

Characterization of particulate and dissolved phosphorus in tile and nearby riverine systems

Science.gov (United States)

Jiang, X.; Arai, Y.; David, M.; Gentry, L.

2017-12-01

In the Midwestern U.S., the drainage of agricultural land is predominantly managed by the tile drain system because of its poorly drain properties of clay rich indigenous soils. An accelerated subsurface flow of phosphorus (P) has recently been documented as a primary P transport path in contrast to the typical surface runoff events observed in the Eastern U.S. Recent studies suggested the important role of particulate P (PP) load in agricultural tile drainage water during high flow events. It was hypothesized that PP in the tile water is transported to riverine system contributing to the negative environmental impacts in the Midwestern U.S. In this study, correlation assessment of physicochemical properties of PP in agricultural tile drainage and nearby river samples after a storm event was conducted using a combination of 31P-nuclear magnetic resonance spectroscopy, P K-edge X-ray absorption near edge structure spectroscopy, X-ray diffraction, zetasizer, and transmission electron microscopy. Results show that significantly more colloidal (i.e. 1 nm- 2 µm) and silt-sized (i.e. > 2 µm) particles as well as higher dissolved total P (DTP) and dissolved reactive P (DRP) concentrations existed in river samples than tile samples. Tile and river samples showed similar zeta potential in each particle-size fraction and similar element distributions on colloidal fraction. However, colloidal P concentration and distribution are slightly different between tile and river samples: more colloidal total P and organic P existed in tile colloids than river colloids. The results of P speciation and mineralogical assessment will also be discussed.

DGT measurement of dissolved aluminum species in waters

DEFF Research Database (Denmark)

Panther, Jared G.; Bennett, William W.; Teasdale, Peter R.

2012-01-01

Aluminum is acutely toxic, and elevated concentrations of dissolved Al can have detrimental effects on both terrestrial and aquatic ecosystems. Robust analytical methods that can determine environmentally relevant Al fractions accurately and efficiently are required by the environmental monitoring...

Titanium distribution in swimming pool water is dominated by dissolved species.

Science.gov (United States)

David Holbrook, R; Motabar, Donna; Quiñones, Oscar; Stanford, Benjamin; Vanderford, Brett; Moss, Donna

2013-10-01

The increased use of titanium dioxide nanoparticles (nano-TiO2) in consumer products such as sunscreen has raised concerns about their possible risk to human and environmental health. In this work, we report the occurrence, size fractionation and behavior of titanium (Ti) in a children's swimming pool. Size-fractionated samples were analyzed for Ti using ICP-MS. Total titanium concentrations ([Ti]) in the pool water ranged between 21 μg/L and 60 μg/L and increased throughout the 101-day sampling period while [Ti] in tap water remained relatively constant. The majority of [Ti] was found in the dissolved phase (microparticulate. Simple models suggest that evaporation may account for the observed variation in [Ti], while sunscreen may be a relevant source of particulate and microparticule Ti. Compared to diet, incidental ingestion of nano-Ti from swimming pool water is minimal. Published by Elsevier Ltd.

Therapeutic use of fractionated total body and subtotal body irradiation

International Nuclear Information System (INIS)

Loeffler, R.K.

1981-01-01

Ninety-one patients were treated using fractionated subtotal body (STBI) or total body irradiation (TBI). These patients had generalized lymphomas, Hodgkin's disease, leukemias, myelomas, seminomas, or oat-cell carcinomas. Subtotal body irradiation is delivered to the entire body, except for the skull and extremities. It was expected that a significantly higher radiation dose could be administered with STBI than with TBI. A five- to ten-fold increase in tolerance for STBI was demonstrated. Many of these patients have had long-term emissions. There is little or no treatment-induced symptomatology, and no sanctuary sites

Comparing the Spectroscopic and Molecular Characteristics of Different Dissolved Organic Matter Fractions Isolated by Hydrophobic and Anionic Exchange Resins Using Fluorescence Spectroscopy and FT-ICR-MS

Directory of Open Access Journals (Sweden)

Morgane Derrien

2017-07-01

Full Text Available Despite the environmental significance of dissolved organic matter (DOM, characterizing DOM is still challenging due to its structural complexity and heterogeneity. In this study, three different chemical fractions, including hydrophobic acid (HPOA, transphilic acid (TPIA, and hydrophilic neutral and base (HPIN/B fractions, were separated from bulk aquatic DOM samples, and their spectral features and the chemical composition at the molecular level were compared using both fluorescence excitation emission matrix-parallel factor analysis (EEM-PARAFAC and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS. The HPIN/B fraction was distinguished from the two acidic fractions (i.e., HPOA and TPIA by the EEM-PARAFAC, while the TPIA fraction was discriminated by using the molecular parameters derived from the FT-ICR MS analyses. Statistical comparison suggests that the spectral dissimilarity among the three chemical fractions might result from the acido-basic properties of DOM samples, while the differences in molecular composition were more likely to be affected by the hydrophobicity of the DOM fractions. The non-metric multidimensional scaling map further revealed that the HPOA was the most heterogeneous among the three fractions. The number of overlapping formulas among the three chemical fractions constituted only <5% of all identified formulas, and those between two different fractions ranged from 2.0% to 24.1%, implying relatively homogeneous properties of the individual chemical fractions with respect to molecular composition. Although employing chemical fractionation achieved a lowering of the DOM heterogeneity, prevalent signatures of either acido-basic property or the hydrophobic nature of DOM on the characteristics of three chemical isolated fractions were not found for this study.

The origin and isotopic composition of dissolved sulfide in groundwater from carbonate aquifers in Florida and Texas

International Nuclear Information System (INIS)

Rye, R.O.; Back, W.; Hanshaw, B.B.; Rightmire, C.T.; Pearson, F.J. Jr.

1981-01-01

The delta 34 S values of dissolved sulfide and the sulfur isotope fractionations between dissolved sulfide and sulfate species in Floridan ground water generally correlate with dissolved sulfate concentrations which are related to flow patterns and residence time within the aquifer. The dissolved sulfide derives from the slow in situ biogenic reduction of sulfate dissolved from sedimentary gypsum in the aquifer. In areas where the water is oldest, the dissolved sulfide has apparently attained isotopic equilibrium with the dissolved sulfate at the temperature of the system. This approach to equilibrium reflects an extremely slow reduction rate of the dissolved sulfate by bacteria; this slow rate probably results from very low concentrations of organic matter in the aquifer. In the reducing part of the Edwards aquifer, Texas, there is a general down-gradient increase in both dissolved sulfide and sulfate concentrations, but neither the delta 34 S values of sulfide nor the sulfide-sulfate isotope fractionation correlates with the ground-water flow pattern. The dissolved sulfide species appear to be derived primarily from biogenic reduction of sulfate ions whose source is gypsum dissolution although upgradient diffusion of H 2 S gas from deeper oil field brines may be important in places. (author)

Size exclusion and anion exchange high performance liquid chromatography for characterizing metals bound to marine dissolved organic matter

International Nuclear Information System (INIS)

García-Otero, Natalia; Bermejo-Barrera, Pilar; Moreda-Piñeiro, Antonio

2013-01-01

Highlights: ► Fractionation methods for assessing metals bound to marine DOM were developed. ► SEC and AEC with UV detection and hyphenated with inductively coupled plasma-mass spectrometry were used. ► SEC-UV showed marine DOM of molecular weights from 16 to 1 kDa. ► Cobalt, manganese, strontium and zinc are bound to marine DOM. - Abstract: Size exclusion chromatography (SEC) followed by anion exchange chromatography (AEC) hyphenated with inductively coupled plasma-mass spectrometry (ICP-MS) was applied for fractionating metals bound to marine dissolved organic matter (DOM). Surface seawater samples (100 L) were subjected to tangential flow ultrafiltration (10,000 Da cut off) for isolating and pre-concentrating dissolved large molecules. The isolated fraction (retentate) consisted of 1 L, which was further freeze-dried and re-dissolved to 250 mL with ultrapure water. After HI Trap desalting of the re-dissolved retentate, SEC with UV detection showed marine DOM ranging from 6.5 kDa (lower than the permeable volume of the SEC column) to 16 kDa. A further characterization of this fraction by AEC with UV detection revealed the existence of four groups of macromolecules exhibiting retention times of 2.3, 2.8, 4.5 and 14.0 min. AEC hyphenated with ICP-MS showed the presence of strontium and zinc in the first AE fraction isolated from the SEC fraction; while manganese was found to be bound to the second AE fraction. Cobalt was found to be bound to molecules comprising the third AE fraction.

Toxicity of dissolved and precipitated aluminium to marine diatoms.

Science.gov (United States)

Gillmore, Megan L; Golding, Lisa A; Angel, Brad M; Adams, Merrin S; Jolley, Dianne F

2016-05-01

Localised aluminium contamination can lead to high concentrations in coastal waters, which have the potential for adverse effects on aquatic organisms. This research investigated the toxicity of 72-h exposures of aluminium to three marine diatoms (Ceratoneis closterium (formerly Nitzschia closterium), Minutocellus polymorphus and Phaeodactylum tricornutum) by measuring population growth rate inhibition and cell membrane damage (SYTOX Green) as endpoints. Toxicity was correlated to the time-averaged concentrations of different aluminium size-fractions, operationally defined as aluminium exposure varied between diatom species. C. closterium was the most sensitive species (10% inhibition of growth rate (72-h IC10) of 80 (55-100)μg Al/L (95% confidence limits)) while M. polymorphus (540 (460-600)μg Al/L) and P. tricornutum (2100 (2000-2200)μg Al/L) were less sensitive (based on measured total aluminium). Dissolved aluminium was the primary contributor to toxicity in C. closterium, while a combination of dissolved and precipitated aluminium forms contributed to toxicity in M. polymorphus. In contrast, aluminium toxicity to the most tolerant diatom P. tricornutum was due predominantly to precipitated aluminium. Preliminary investigations revealed the sensitivity of C. closterium and M. polymorphus to aluminium was influenced by initial cell density with aluminium toxicity significantly (paluminium toxicity to diatoms do not involve compromising the plasma membrane. These results indicate that marine diatoms have a broad range in sensitivity to aluminium with toxic mechanisms related to both dissolved and precipitated aluminium. Copyright © 2016 Elsevier B.V. All rights reserved.

Characterization and biotoxicity assessment of dissolved organic matter in RO concentrate from a municipal wastewater reclamation reverse osmosis system.

Science.gov (United States)

Sun, Ying-Xue; Gao, Yue; Hu, Hong-Ying; Tang, Fang; Yang, Zhe

2014-12-01

Reverse osmosis (RO) concentrate from municipal wastewater reclamation reverse osmosis (mWRRO) system containing organic compounds may associate with toxic risk, and its discharge might pose an environmental risk. To identify a basis for the selection of feasible technology in treating RO concentrates, the characteristics and biotoxicity of different fractions of dissolved organic matter (DOM) in RO concentrates from an mWRRO system were investigated. The results indicated that the hydrophilic neutrals (HIN), hydrophobic acids (HOA) and hydrophobic bases (HOB) accounted for 96% of the dissolved organic carbon (DOC) of the total DOM in the RO concentrate. According to the SEC chromatograph detected at 254 nm wavelength of UV, the DOM with molecular weight (MW) 1-3 kDa accounted for the majority of the basic and neutral fractions. The fluorescence spectra of the excitation emission matrix (EEM) indicated that most aromatic proteins, humic/fulvic acid-like and soluble microbial by-product-like substances existed in the fractions HOA and hydrophobic neutrals (HON). The genotoxicity and anti-estrogenic activity of the RO concentrate were 1795.6 ± 57.2 μg 4-NQOL(-1) and 2.19 ± 0.05 mg TAM L(-1), respectively. The HIN, HOA, and HOB contributed to the genotoxicity of the RO concentrate, and the HIN was with the highest genotoxic level of 1007.9 ± 94.8 μg 4-NQOL(-1). The HOA, HON, and HIN lead to the total anti-estrogenic activity of the RO concentrate, and HOA occupied approximately 60% of the total, which was 1.3 ± 0.17 mg TAM L(-1). Copyright © 2014 Elsevier Ltd. All rights reserved.

Benefits of online in vivo dosimetry for single-fraction total body irradiation

Energy Technology Data Exchange (ETDEWEB)

Eaton, David J., E-mail: davideaton@nhs.net [Department of Radiotherapy, Royal Free Hospital, London (United Kingdom); Warry, Alison J. [Department of Radiotherapy Physics, University College London Hospital, London (United Kingdom); Trimble, Rachel E.; Vilarino-Varela, Maria J.; Collis, Christopher H. [Department of Radiotherapy, Royal Free Hospital, London (United Kingdom)

2014-01-01

Use of a patient test dose before single-fraction total body irradiation (TBI) allows review of in vivo dosimetry and modification of the main treatment setup. However, use of computed tomography (CT) planning and online in vivo dosimetry may reduce the need for this additional step. Patients were treated using a supine CT-planned extended source-to-surface distance (SSD) technique with lead compensators and bolus. In vivo dosimetry was performed using thermoluminescent dosimeters (TLDs) and diodes at 10 representative anatomical locations, for both a 0.1-Gy test dose and the treatment dose. In total, 28 patients were treated between April 2007 and July 2013, with changes made in 10 cases (36%) following test dose results. Overall, 98.1% of measured in vivo treatment doses were within 10% of the prescribed dose, compared with 97.0% of test dose readings. Changes made following the test dose could have been applied during the single-fraction treatment itself, assuming that the dose was delivered in subportions and online in vivo dosimetry was available for all clinically important anatomical sites. This alleviates the need for a test dose, saving considerable time and resources.

Benefits of online in vivo dosimetry for single-fraction total body irradiation

International Nuclear Information System (INIS)

Eaton, David J.; Warry, Alison J.; Trimble, Rachel E.; Vilarino-Varela, Maria J.; Collis, Christopher H.

2014-01-01

Use of a patient test dose before single-fraction total body irradiation (TBI) allows review of in vivo dosimetry and modification of the main treatment setup. However, use of computed tomography (CT) planning and online in vivo dosimetry may reduce the need for this additional step. Patients were treated using a supine CT-planned extended source-to-surface distance (SSD) technique with lead compensators and bolus. In vivo dosimetry was performed using thermoluminescent dosimeters (TLDs) and diodes at 10 representative anatomical locations, for both a 0.1-Gy test dose and the treatment dose. In total, 28 patients were treated between April 2007 and July 2013, with changes made in 10 cases (36%) following test dose results. Overall, 98.1% of measured in vivo treatment doses were within 10% of the prescribed dose, compared with 97.0% of test dose readings. Changes made following the test dose could have been applied during the single-fraction treatment itself, assuming that the dose was delivered in subportions and online in vivo dosimetry was available for all clinically important anatomical sites. This alleviates the need for a test dose, saving considerable time and resources

Dissolved organic phosphorus and its bioavailable fraction in the Baltic Sea

Science.gov (United States)

Nausch, M.; Nausch, G.; Setzkorn, D.; Welz, Ä.

2009-04-01

In general, it is accepted that dissolved organic phosphorus (DOP) is besides dissolved inorganic phosphorus (DIP) a source for phosphorus nutrition of phyto- and bacterioplankton. If available, DIP is usually preferred to DOP. DOP becomes the most important source under DIP depleted conditions occurring in the Baltic Sea in summer. However, its contribution to nutrition and consequently its significance is very difficult to appraise because only the bioavailable fraction (BAP = bioavailable phosphorus) can be used by organisms. DOP comprises also inert compounds which persist over longer periods. Therefore, there is an urgent need to quantify the bioavailable DOP. In 2004 and 2005, DOP and BAP concentrations were detected in surface water at three stations in the central Baltic Sea from May until July. In June/July 2008 an intensive measuring campaign was performed throughout the whole Baltic Sea. DOP measurements were done from the entrance to the North Sea in the West until the innermost parts of the Gulf of Bothnia in the North and the Gulf of Finland in the East. BAP was determined at 14 stations in the central and northern parts. DOP was determined using the alkaline potassium peroxidisulphate oxidation method followed by the manual DIP determination. BAP has been detected in time course experiments using 0.8 µm filtered sea water containing free-living heterotrophic bacteria and amended with 7 µM ammonium chloride and 1mg l-1 D-(+) glucosemonohydrate to prevent nitrogen and carbon limitation and increase the phosphorus demand in bacteria. BAP is defined as that proportion of DOP which is used by bacteria and calculated as the difference of DOP concentrations at the beginning and the lowest concentrations during an incubation for 4-6 days. In 2004 and 2005, most DOP concentrations ranged between 0.18 and 0.32 µM, with a declining tendency from spring to summer probably due to elevated uptake compared to its release caused by higher temperatures and DIP

Dissolved organic nitrogen recalcitrance and bioavailable nitrogen quantification for effluents from advanced nitrogen removal wastewater treatment facilities

International Nuclear Information System (INIS)

Fan, Lu; Brett, Michael T.; Jiang, Wenju; Li, Bo

2017-01-01

The objective of this study was to determine the composition of nitrogen (N) in the effluents of advanced N removal (ANR) wastewater treatment plants (WWTPs). This study also tested two different experimental protocols for determining dissolved N recalcitrance. An analysis of 15 effluent samples from five WWTPs, showed effluent concentrations and especially effluent composition varied greatly from one system to the other, with total nitrogen (TN) ranging between 1.05 and 8.10 mg L −1 . Nitrate (NO 3 − ) accounted for between 38 ± 32% of TN, and ammonium accounted for a further 29 ± 28%. All of these samples were dominated by dissolved inorganic nitrogen (DIN; NO 3 −  + NH 4 + ), and uptake experiments indicated the DIN fraction was as expected highly bioavailable. Dissolved organic N (DON) accounted for 20 ± 11% for the total dissolved N in these effluents, and uptake experiments indicated the bioavailability of this fraction varied between 27 ± 26% depending on the WWTP assessed. These results indicate near complete DIN removal should be the primary goal of ANR treatment systems. The comparison of bioavailable nitrogen (BAN) quantification protocols showed that the dissolved nitrogen uptake bioassay approach was clearly a more reliable way to determine BAN concentrations compared to the conventional cell yield protocol. Moreover, because the nitrogen uptake experiment was much more sensitive, this protocol made it easier to detect extrinsic factors (such as biological contamination or toxicity) that could affect the accuracy of these bioassays. Based on these results, we recommend the nitrogen uptake bioassay using filtered and autoclaved samples to quantify BAN concentrations. However, for effluent samples indicating toxicity, algal bioassays will not accurately quantify BAN. - Highlights: • DIN was the dominated N pool for most of the tested effluent samples. • DON bioavailability considerably varied depending on the WWTP assessed. �

Characterization of Urban Runoff Pollution between Dissolved and Particulate Phases

OpenAIRE

Wei, Zhang; Simin, Li; Fengbing, Tang

2013-01-01

To develop urban stormwater management effectively, characterization of urban runoff pollution between dissolved and particulate phases was studied by 12 rainfall events monitored for five typical urban catchments. The average event mean concentration (AEMC) of runoff pollutants in different phases was evaluated. The AEMC values of runoff pollutants in different phases from urban roads were higher than the ones from urban roofs. The proportions of total dissolved solids, total dissolved nitr...

The role of baseflow in dissolved solids delivery to streams in the Upper Colorado River Basin

Science.gov (United States)

Rumsey, C.; Miller, M. P.; Schwarz, G. E.; Susong, D.

2017-12-01

Salinity has a major effect on water users in the Colorado River Basin, estimated to cause almost $300 million per year in economic damages. The Colorado River Basin Salinity Control Program implements and manages projects to reduce salinity (dissolved solids) loads, investing millions of dollars per year in irrigation upgrades, canal projects, and other mitigation strategies. To inform and improve mitigation efforts, there is a need to better understand sources of salinity to streams and how salinity has changed over time. This study explores salinity in baseflow, or groundwater discharge to streams, to assess whether groundwater is a significant contributor of dissolved solids to streams in the Upper Colorado River Basin (UCRB). Chemical hydrograph separation was used to estimate long-term mean annual baseflow discharge and baseflow dissolved solids loads at stream gages (n=69) across the UCRB. On average, it is estimated that 89% of dissolved solids loads originate from the baseflow fraction of streamflow. Additionally, a statistical trend analysis using weighted regressions on time, discharge, and season was used to evaluate changes in baseflow dissolved solids loads in streams with data from 1987 to 2011 (n=29). About two-thirds (62%) of these streams showed statistically significant decreasing trends in baseflow dissolved solids loads. At the two most downstream sites, Green River at Green River, UT and Colorado River at Cisco, UT, baseflow dissolved solids loads decreased by a combined 780,000 metric tons, which is approximately 65% of the estimated basin-scale decrease in total dissolved solids loads in the UCRB attributed to salinity control efforts. Results indicate that groundwater discharged to streams, and therefore subsurface transport processes, play a large role in delivering dissolved solids to streams in the UCRB. Decreasing trends in baseflow dissolved solids loads suggest that salinity mitigation projects, changes in land use, and/or climate are

Fractionation of fulvic acid by iron and aluminum oxides: influence on copper toxicity to Ceriodaphnia dubia

Science.gov (United States)

Smith, Kathleen S.; Ranville, James F.; Lesher, Emily K.; Diedrich, Daniel J.; McKnight, Diane M.; Sofield, Ruth M.

2014-01-01

This study examines the effect on aquatic copper toxicity of the chemical fractionation of fulvic acid (FA) that results from its association with iron and aluminum oxyhydroxide precipitates. Fractionated and unfractionated FAs obtained from streamwater and suspended sediment were utilized in acute Cu toxicity tests on ,i>Ceriodaphnia dubia. Toxicity test results with equal FA concentrations (6 mg FA/L) show that the fractionated dissolved FA was 3 times less effective at reducing Cu toxicity (EC50 13 ± 0.6 μg Cu/L) than were the unfractionated dissolved FAs (EC50 39 ± 0.4 and 41 ± 1.2 μg Cu/L). The fractionation is a consequence of preferential sorption of molecules having strong metal-binding (more aromatic) moieties to precipitating Fe- and Al-rich oxyhydroxides, causing the remaining dissolved FA to be depleted in these functional groups. As a result, there is more bioavailable dissolved Cu in the water and hence greater potential for Cu toxicity to aquatic organisms. In predicting Cu toxicity, biotic ligand models (BLMs) take into account dissolved organic carbon (DOC) concentration; however, unless DOC characteristics are accounted for, model predictions can underestimate acute Cu toxicity for water containing fractionated dissolved FA. This may have implications for water-quality criteria in systems containing Fe- and Al-rich sediment, and in mined and mineralized areas in particular. Optical measurements, such as specific ultraviolet absorbance at 254 nm (SUVA254), show promise for use as spectral indicators of DOC chemical fractionation and inferred increased Cu toxicity.

Size-fractionated dissolved primary production and carbohydrate composition of the coccolithophore Emiliania huxleyi

Science.gov (United States)

Borchard, C.; Engel, A.

2015-02-01

Extracellular release (ER) by phytoplankton is the major source of fresh dissolved organic carbon (DOC) in marine ecosystems and accompanies primary production during all growth phases. Little is known, so far, on size and composition of released molecules, and to which extent ER occurs passively, by leakage, or actively, by exudation. Here, we report on ER by the widespread and bloom-forming coccolithophore Emiliania huxleyi grown under steady-state conditions in phosphorus-controlled chemostats (N:P = 29, growth rate of μ = 0.2 d-1) at present-day and high-CO2 concentrations. 14C incubations were performed to determine primary production (PP), comprised of particulate (PO14C) and dissolved organic carbon (DO14C). Concentration and composition of particulate combined carbohydrates (pCCHO) and high-molecular-weight (>1 kDa, HMW) dissolved combined carbohydrates (dCCHO) were determined by ion chromatography. Information on size distribution of ER products was obtained by investigating distinct size classes (10 kDa was significantly different, with a higher mol% of arabinose. The mol% of acidic sugars increased and that of glucose decreased with increasing size of HMW-dCCHO. We conclude that larger polysaccharides follow different production and release pathways than smaller molecules, potentially serving distinct ecological and biogeochemical functions.

ORGANIC CARBON AND TOTAL NITROGEN IN THE DENSIMETRIC FRACTIONS OF ORGANIC MATTER UNDER DIFFERENT SOIL MANAGEMEN

Directory of Open Access Journals (Sweden)

MARCELO RIBEIRO VILELA PRADO

2016-01-01

Full Text Available The evaluation of land use and management by the measurement of soil organic matter and its fractions has gained attention since it helps in the understanding of the dynamics of their contribution to soil productivity, especially in tropical environments. This study was conducted in the municipality of Colorado do Oeste, state of Rondônia, Brazil and its aim was to determinethe quantity of organic carbon and total nitrogen in the light and heavy fractions of organic matter in the surface layers of a typic hapludalf under different land use systems: Native Forest: open evergreen forest, reference environment; Agroforestry System 1: teak (Tectona grandis LF and kudzu (Pueraria montana; Agroforestry System 2: coffee (Coffea canephora, marandu palisade grass (Brachiaria brizantha cv. Marandu, “pinho cuiabano” (Parkia multijuga, teak and kudzu.; Agroforestry System 3: teak and cocoa (Theobroma cacao; Silvopasture System: teak, cocoa and marandu palisade grass; and Extensive Grazing System: marandu palisade grass. The experimental design was a randomized block in split-split plots (use systems versus soil layers of 0-0.05 and 0.05-0.10 m with three replications. The results showed that relative to Native Forest, the Agroforestry System 2 had equal- and greater amounts of organic carbon and total nitrogen respectively (light and heavy fractions in the soil organic matter, with the light fraction being responsible for storage of approximately 45% and 70% of the organic carbon and total nitrogen, respectively. Therefore, the light densimetric fraction proved to be useful in the early identification of the general decline of the soil organic matter in the land use systems evaluated.

2-Nitrophenol reduction promoted by S. putrefaciens 200 and biogenic ferrous iron: The role of different size-fractions of dissolved organic matter

Energy Technology Data Exchange (ETDEWEB)

Zhu, Zhenke [Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650 (China); Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Tao, Liang, E-mail: taoliang@soil.gd.cn [Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650 (China); Li, Fangbai, E-mail: cefbli@soil.gd.cn [Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650 (China)

2014-08-30

Graphical abstract: - Highlights: • Dissolved organic matter (DOM) act as electron shuttle in redox reactions. • Different molecular weight DOM fractions have different electron transfer capacity. • A higher electron transfer capacities value indicates a higher reduction rate. • DOM transfer electron from S. putrefaciens 200 to 2-nitrophenol (2-NP) and Fe(III). • DOM and biogenic Fe(II) synergistically enhanced the 2-NP reductive transformation. - Abstract: The reduction of nitroaromatic compounds (listed as a priority pollutant) in natural subsurface environments typically coexists with dissimilatory reduction of iron oxides effected by dissolved organic matter (DOM). Investigating the impact of the DOM that influences those reduction processes is crucial for understanding and predicting the geochemical fate of these environmental species. This study investigated the impact of different molecular weight DOM fractions (DMWDs) on the 2-nitrophenol (2-NP) reduction by S. putrefaciens 200 (SP200) and α-Fe{sub 2}O{sub 3} with lactate (excluding electron donor interference). Kinetic measurements demonstrated that 2-NP reduction rates were affected by the redox reactivity of active species under DMWDs (denoted as L-DOM, M-DOM, and H-DOM). The enhanced reduction rates are consistent with the negative shifts in peak oxidation potential values, the increases in HA-like/FA-like values, aromaticity index values and electron transfer capacity values. L-DOM acted mainly as ligands to complex Fe(II), whereas the significant role of H-DOM in reductive reactions should be acting as an electron shuttle, transferring electrons from SP200 to Fe(III) and 2-NP and from biogenic Fe(II) to 2-NP, further accelerating the 2-NP reductions. Those observations provide valuable insights into the role of DOM in the biogeochemical redox processes and the remediation of contaminated soil in a natural environment.

Distribution of dissolved carbohydrates and uronic acids in a tropical estuary, India

Digital Repository Service at National Institute of Oceanography (India)

Khodse, V.B.; Bhosle, N.B.; Matondkar, S.G.P.

, concentrations of total dissolved carbohydrate (TCHO), dissolved polysaccharide (PCHO), dissolved monosaccharide (MCHO), and dissolved uronic acid (URA) were measured in the Mandovi estuary, west coast of India during the monsoon and premonsoon seasons...

Degradation of riverine dissolved organic matter by seawater bacteria

NARCIS (Netherlands)

Rochelle-Newall, E.J.; Pizay, M-D.; Middelburg, J.J.; Boschker, H.T.S.; Gattuso, J.P.

2004-01-01

The functional response of a seawater bacterial community transplanted into freshwater dissolved organic matter (DOM) was investigated together with the response of natural populations of bacteria to size-fractioned natural source water. Seawater bacteria were incubated over a period of 8 d in

Fate of phosphorus fractions in an adsorptive-filter subject to intra- and inter-event runoff phenomena.

Science.gov (United States)

Berretta, Christian; Sansalone, John

2012-07-30

In-situ filtration of phosphorus (P) and particulate matter (PM) transported in runoff is increasingly implemented for urban source areas. While monitoring of filter response is commonly based on an event mean of total phosphorus (TP), this study examines the fate of specific P fractions through intra- and inter-event phenomena. This continuous filter monitoring program includes 15 wet weather loadings and the dry weather periods between these events. Aqueous P adsorption and PM-bound P (suspended, settleable and sediment) filtration phenomena are examined for runoff events from a landscaped carpark with biogenic loads in Gainesville (GNV), FL. Filter response is compared to a similar aluminum oxide Al-Ox modified media filter subject to anthropogenic loads from an urban paved source area in Baton Rouge (BTR), LA. Results for the GNV filter indicate that while intra-event settleable, sediment and dissolved P fractions are controlled by the filter, the suspended P fraction remained relatively mobile compared to the other P fractions. P adsorption is primarily influenced by intra-event flow rates, contact times, runoff volume, pH and by the inter-event chemistry of runoff stored in the filter. P effluent partitioning is dominated by the suspended PM as a consequence of effective adsorption by the filter. Inter-event phenomena generate decreasing redox with commensurate increases in alkalinity, conductivity as well as dissolved P as a consequence of re-partitioning. Dissolved P fate suggests that filters should be designed and managed to remain aerobic between wet weather events. For effective separation of suspended P and PM fractions by passive filters with low driving head, sustainability of performance, including head loss {<3 kPa}, requires upstream volumetric attenuation. Copyright © 2012 Elsevier Ltd. All rights reserved.

The hydrophilic/hydrophobic ratio vs. dissolved organics removal by coagulation – A review

Directory of Open Access Journals (Sweden)

Djamel Ghernaout

2014-07-01

Full Text Available This review discusses the hydrophilic/hydrophobic ratio as a function of the hydrophilic and hydrophobic contents removal by coagulation process. It is well established that coagulation process could bring a reduction in dissolved organic carbon of around 30–60% by increasing the coagulant dose and optimising reaction pH, in which large organic molecules with hydrophobic property was removed preferentially. Furthermore, the literature affirmed that the greater removal of UV-absorbing substances indicates that alum coagulation preferentially removed the hydrophobic fraction of the total organic carbon. For the hydrophobic fraction, it needs to be removed entirely without its transformation into hydrophilic fractions by coagulation process avoiding pre-chlorination/pre-oxidation due to the risk of organic molecules fragmentation. Determining the exact numerical values of the hydrophilic/hydrophobic ratio for raw water and treated water at different stages of the treatment processes in a water treatment plant, as for the DCO/DBO5 ratio in the case of wastewater treatment, would help on more focusing on OM control and removal.

Kinetic isotopic fractionation during diffusion of ionic species in water

Science.gov (United States)

Richter, Frank M.; Mendybaev, Ruslan A.; Christensen, John N.; Hutcheon, Ian D.; Williams, Ross W.; Sturchio, Neil C.; Beloso, Abelardo D.

2006-01-01

Experiments specifically designed to measure the ratio of the diffusivities of ions dissolved in water were used to determine DLi/DK,D/D,D/D,D/D,andD/D. The measured ratio of the diffusion coefficients for Li and K in water (D Li/D K = 0.6) is in good agreement with published data, providing evidence that the experimental design being used resolves the relative mobility of ions with adequate precision to also be used for determining the fractionation of isotopes by diffusion in water. In the case of Li, we found measurable isotopic fractionation associated with the diffusion of dissolved LiCl (D/D=0.99772±0.00026). This difference in the diffusion coefficient of 7Li compared to 6Li is significantly less than that reported in an earlier study, a difference we attribute to the fact that in the earlier study Li diffused through a membrane separating the water reservoirs. Our experiments involving Mg diffusing in water found no measurable isotopic fractionation (D/D=1.00003±0.00006). Cl isotopes were fractionated during diffusion in water (D/D=0.99857±0.00080) whether or not the co-diffuser (Li or Mg) was isotopically fractionated. The isotopic fractionation associated with the diffusion of ions in water is much smaller than values we found previously for the isotopic fractionation of Li and Ca isotopes by diffusion in molten silicate liquids. A major distinction between water and silicate liquids is that water surrounds dissolved ions with hydration shells, which very likely play an important but still poorly understood role in limiting the isotopic fractionation associated with diffusion.

Long-term survival of skin allografts in mice treated with fractionated total lymphoid irradiation

International Nuclear Information System (INIS)

Slavin, S.; Strober, S.; Fuks, Z.; Kaplan, H.S.

1976-01-01

Treatment of recipient Balb/c mice with fractionated, high-dose total lymphoid irradiation, a procedure commonly used in the therapy of human malignant lymphomas, resulted in fivefold prolongation of the survival of C57BL/Ka skin allografts despite major histocompatibility differences between the strains (H-2/sup d/ and H-2/sup b/, respectively). Infusion of 10 7 (C57BL/Ka x Balb/c)F 1 bone marrow cells after total lymphoid irradiation further prolonged C57BL/Ka skin graft survival to more than 120 days. Total lymphoid irradiation may eventually prove useful in clinical organ transplantation

Solid and suspended/dissolved waste (N, P, O) from rainbow trout (Oncorynchus mykiss)

DEFF Research Database (Denmark)

Dalsgaard, Anne Johanne Tang; Pedersen, Per Bovbjerg

2011-01-01

differences between the dietary treatment groups in the waste produced. On average, 48% of the ingestedNwas recovered in thewater (TANconstituting 64–79%of this)and7% inthesolids. In comparison, 1% of the ingested P was recovered in the water and 43% in the solids. A breakpoint value of 5.6 g standardized......Quantifying aquaculture waste into different waste fractions will make it possible to design different treatment setups for obtaining specific cleaning objectives. The aim of this study was therefore to measure “all” solid and suspended/dissolved (i.e. unsedimented) waste from juvenile rainbow...... trout (Oncorynchus mykiss) fed three commonly applied commercial diets, “all” waste referring to: total nitrogen (N), total ammonia nitrogen (TAN=NH3-N+NH4-N), total phosphorus (P), and organicmatter characterized by the chemical oxygen demand (COD) and the biological oxygen demand after 5 days (BOD5...

Accuracy of different sensors for the estimation of pollutant concentrations (total suspended solids, total and dissolved chemical oxygen demand) in wastewater and stormwater.

Science.gov (United States)

Lepot, Mathieu; Aubin, Jean-Baptiste; Bertrand-Krajewski, Jean-Luc

2013-01-01

Many field investigations have used continuous sensors (turbidimeters and/or ultraviolet (UV)-visible spectrophotometers) to estimate with a short time step pollutant concentrations in sewer systems. Few, if any, publications compare the performance of various sensors for the same set of samples. Different surrogate sensors (turbidity sensors, UV-visible spectrophotometer, pH meter, conductivity meter and microwave sensor) were tested to link concentrations of total suspended solids (TSS), total and dissolved chemical oxygen demand (COD), and sensors' outputs. In the combined sewer at the inlet of a wastewater treatment plant, 94 samples were collected during dry weather, 44 samples were collected during wet weather, and 165 samples were collected under both dry and wet weather conditions. From these samples, triplicate standard laboratory analyses were performed and corresponding sensors outputs were recorded. Two outlier detection methods were developed, based, respectively, on the Mahalanobis and Euclidean distances. Several hundred regression models were tested, and the best ones (according to the root mean square error criterion) are presented in order of decreasing performance. No sensor appears as the best one for all three investigated pollutants.

Phase-II trial of fractionated total body radiation in bone marrow transplantation for acute leukemia

International Nuclear Information System (INIS)

Gale, R.P.; Opelz, G.; Feig, S.

1979-01-01

The addition of low doses of fractionated total body irradiation and a radiosensitizing agent to more conventional doses of total body irradiation was well tolerated but did not improve the antileukemic effect. The DAFT regimen was not associated with a higher incidence of GVHD or interstitial pneumonitis. This observation has led us to consider escalation of the dose of FTBI in our next clinical trial

Fractionated total lymphoid irradiation as preparative immunosuppression in high risk renal transplantation

International Nuclear Information System (INIS)

Najarian, J.S.; Ferguson, R.M.; Sutherland, D.E.; Slavin, S.; Kim, T.; Kersey, J.; Simmons, R.L.

1982-01-01

Twenty-two patients at high risk to reject renal allografts have been treated with fractionated total lymphoid irradiation (FTLI) prior to transplantation of primary (2), secondary (16) or tertiary (4) renal allografts. All patients undergoing retransplantation had rapidly rejected previous grafts. At 24 months following transplantation, 72% of grafts were functioning in the TLI group compared with a 38% graft function in an historical control group of recipients receiving secondary or tertiary grafts and treated with conventional immunosuppression. Important variables in determining success of transplantation following fractionated TLI include the dose of TLI, the interval from radiation to transplantation, and maintenance post-transplant immunosuppressive therapy. Optimal results were achieved with 2500 rads delivered in 100 rad fractions followed by transplantation within two weeks, and a tapering prednisone schedule and maintenance azathioprine post-transplantation. Seventeen patients had significant complications of the radiation treatment and there was one death, prior to transplantation, associated with pneumonitis. In vitro assessment of immune function demonstrated marked peripheral T cell depletion and loss of in vitro responsiveness to mitogen and allogeneic stimulation following FTLI. The administration of donor bone marrow at the time of transplantation did not produce chimerism. The results suggest that when properly utilized FTLI can produce effective adjunctive immunosuppression for clinical transplantation

Chemical composition and cycling of dissolved organic matter in the Mid-Atlantic Bight

Science.gov (United States)

Aluwihare, Lihini I.; Repeta, Daniel J.; Chen, Robert F.

This study focuses on the chemical characterization of high molecular-weight dissolved organic matter (HMW DOM) isolated from the Middle Atlantic Bight in April 1994 and March 1996. Using proton nuclear magnetic resonance spectroscopy ( 1HNMR) and monosaccharide analysis we compared both spatial and temporal variations in the chemical structure of HMW DOM across this region. Our analyses support the presence of at least two compositionally distinct components to HMW DOM. The major component is acyl polysaccharide (APS), a biopolymer rich in carbohydrates, acetate and lipid, accounting for between 50% and 80% of the total high molecular-weight dissolved organic carbon (HMW DOC) in surface samples. APS is most abundant in fully marine, surface-water samples, and is a product of autochthonous production. Organic matter with spectral properties characteristic of humic substances is the second major component of HMW DOM. Humic substances are most abundant (up to 49% of the total carbon) in samples collected from estuaries, near the coast, and in deep water, suggesting both marine and perhaps terrestrial sources. Radiocarbon analyses of neutral monosaccharides released by the hydrolysis of APS have similar and modern (average 71‰) Δ 14C values. Radiocarbon data support our suggestion that these sugars occur as part of a common macromolecule, with an origin via recent biosynthesis. Preliminary radiocarbon data for total neutral monosaccharides isolated from APS at 300 and 750 m show this fraction to be substantially enriched relative to total HMW DOC and DOC. The relatively enriched radiocarbon values of APS at depth suggest APS is rapidly transported into the deep ocean.

Cumulative effects of cascade hydropower stations on total dissolved gas supersaturation.

Science.gov (United States)

Ma, Qian; Li, Ran; Feng, Jingjie; Lu, Jingying; Zhou, Qin

2018-03-01

Elevated levels of total dissolved gas (TDG) may occur downstream of dams during the spill process. These high levels would increase the incidence of gas bubble disease in fish and cause severe environmental impacts. With increasing numbers of cascade hydropower stations being built or planned, the cumulative effects of TDG supersaturation are becoming increasingly prominent. The TDG saturation distribution in the downstream reaches of the Jinsha River was studied to investigate the cumulative effects of TDG supersaturation resulting from the cascade hydropower stations. A comparison of the effects of the joint operation and the single operation of two hydropower stations (XLD and XJB) was performed to analyze the risk degree to fish posed by TDG supersaturation. The results showed that water with supersaturated TDG generated at the upstream cascade can be transported to the downstream power station, leading to cumulative TDG supersaturation effects. Compared with the single operation of XJB, the joint operation of both stations produced a much higher TDG saturation downstream of XJB, especially during the non-flood discharge period. Moreover, the duration of high TDG saturation and the lengths of the lethal and sub-lethal areas were much higher in the joint operation scenario, posing a greater threat to fish and severely damaging the environment. This work provides a scientific basis for strategies to reduce TDG supersaturation to the permissible level and minimize the potential risk of supersaturated TDG.

Relation between PAH and black carbon contents in size fractions of Norwegian harbor sediments

International Nuclear Information System (INIS)

Oen, Amy M.P.; Cornelissen, Gerard; Breedveld, Gijs D.

2006-01-01

Distributions of total organic carbon (TOC), black carbon (BC), and polycyclic aromatic hydrocarbons (PAH) were investigated in different particle size fractions for four Norwegian harbor sediments. The total PAH (16-EPA) concentrations ranged from 2 to 113 mg/kg dry weight with the greatest fraction of PAH mass in the sand fraction for three of the four sediments. TOC contents ranged from 0.84% to 14.2% and BC contents from 0.085% to 1.7%. This corresponds to organic carbon (OC = TOC - BC) contents in the range of 0.81-14% and BC:TOC ratios of 1.3-18.1%. PAH isomer ratios suggested that the PAH in all four sediments were of pyrogenic origin. Furthermore, stronger correlations between PAH versus BC (r 2 = 0.85) than versus OC (r 2 = 0.15) were found. For all size fractions and bulk sediments, the PAH-to-BC ratios for the total PAHs were on average 6 ± 3 mg PAH/g BC. These results suggest that PAH distributions were dominated by the presence of BC, rather than OC. As sorption to BC is much stronger than sorption to OC, this may result in significantly lower dissolved concentrations of PAH than expected on the basis of organic carbon partitioning alone. - PAH contents correlated better with black carbon than organic carbon for four Norwegian harbor sediments

Dissolved inorganic carbon, total alkalinity, pH, dissolved oxygen, and nutrients collected from profile, discrete sampling, and time series observations using CTD, Niskin bottle, and other instruments from R/V Gulf Challenger near a buoy off the coast of New Hampshire, U.S. in the Gulf of Maine from 2011-01-11 to 2015-11-18 (NCEI Accession 0142327)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains discrete measurements of dissolved inorganic carbon, total alkalinity, pH, dissolved oxygen, and nutrients collected at the buoy off...

Changes in the fraction of total hypoxia and hypoxia subtypes in human squamous cell carcinomas upon fractionated irradiation: Evaluation using pattern recognition in microcirculatory supply units

International Nuclear Information System (INIS)

Maftei, Constantin-Alin; Bayer, Christine; Shi, Kuangyu; Astner, Sabrina T.; Vaupel, Peter

2011-01-01

Background and purpose: Evaluate changes in total hypoxia and hypoxia subtypes in vital tumor tissue of human head and neck squamous cell carcinomas (hHNSCC) upon fractionated irradiation. Materials and methods: Xenograft tumors were generated from 5 hHNSCC cell lines (UT-SCC-15, FaDu, SAS, UT-SCC-5 and UT-SCC-14). Hypoxia subtypes were quantified in cryosections based on (immuno-)fluorescent marker distribution patterns of Hoechst 33342 (perfusion), pimonidazole (hypoxia) and CD31 (endothelium) in microcirculatory supply units (MCSUs). Tumors were irradiated with 5 or 10 fractions of 2 Gy, 5×/week. Results: Upon irradiation with 10 fractions, the overall fraction of hypoxic MCSUs decreased in UT-SCC-15, FaDu and SAS, remained the same in UT-SCC-5 and increased in UT-SCC-14. Decreases were observed in the proportion of chronically hypoxic MCSUs in UT-SCC-15, in the fraction of acutely hypoxic MCSUs in UT-SCC-15 and SAS, and in the percentage of hypoxemically hypoxic MCSUs in SAS tumors. After irradiation with 5 fractions, there were no significant changes in hypoxia subtypes. Changes in the overall fraction of hypoxic MCSUs were comparable to corresponding alterations in the proportions of acutely hypoxic MCSUs. There was no correlation between radiation resistance (TCD 50 ) and any of the investigated hypoxic fractions upon fractionated irradiation. Conclusions: This study shows that there are large alterations in the fractions of hypoxia subtypes upon irradiation that can differ from changes in the overall fraction of hypoxic MCSUs.

Molecular size-dependent abundance and composition of dissolved organic matter in river, lake and sea waters.

Science.gov (United States)

Xu, Huacheng; Guo, Laodong

2017-06-15

Dissolved organic matter (DOM) is ubiquitous in natural waters. The ecological role and environmental fate of DOM are highly related to the chemical composition and size distribution. To evaluate size-dependent DOM quantity and quality, water samples were collected from river, lake, and coastal marine environments and size fractionated through a series of micro- and ultra-filtrations with different membranes having different pore-sizes/cutoffs, including 0.7, 0.4, and 0.2 μm and 100, 10, 3, and 1 kDa. Abundance of dissolved organic carbon, total carbohydrates, chromophoric and fluorescent components in the filtrates decreased consistently with decreasing filter/membrane cutoffs, but with a rapid decline when the filter cutoff reached 3 kDa, showing an evident size-dependent DOM abundance and composition. About 70% of carbohydrates and 90% of humic- and protein-like components were measured in the definition of DOM and its size continuum in quantity and quality in aquatic environments. Copyright © 2017 Elsevier Ltd. All rights reserved.

Dissolved organic carbon in the INDEX area of the Central Indian Basin

Digital Repository Service at National Institute of Oceanography (India)

Sardessai, S.; De

-Sea Research II 48 (2001) 3353–3361 Dissolved organic carbon in the INDEX area of the Central Indian Basin Sugandha Sardessai*, S.N. de Sousa National Institute of Oceanography, Dona-Paula, Goa 403 004, India Abstract Dissolved organic carbon (DOC..., 1996). While there is substantial information available on the DOC content of sea water throughout the Atlantic, Pacific and southern oceans, there are limited reports on contents and distribution of this organic fraction in the Indian Ocean (Menzel...

Fractional, biodegradable and spectral characteristics of extracted and fractionated sludge extracellular polymeric substances.

Science.gov (United States)

Wei, Liang-Liang; Wang, Kun; Zhao, Qing-Liang; Jiang, Jun-Qiu; Kong, Xiang-Juan; Lee, Duu-Jong

2012-09-15

Correlation between fractional, biodegradable and spectral characteristics of sludge extracellular polymeric substances (EPS) by different protocols has not been well established. This work extracted sludge EPS using alkaline extractants (NH₄OH and formaldehyde + NaOH) and physical protocols (ultrasonication, heating at 80 °C or cation exchange resin (CER)) and then fractionated the extracts using XAD-8/XAD-4 resins. The alkaline extractants yielded more sludge EPS than the physical protocols. However, the physical protocols extracted principally the hydrophilic components which were readily biodegradable by microorganisms. The alkaline extractants dissolved additional humic-like substances from sludge solids which were refractory in nature. Different extraction protocols preferably extracted EPS with distinct fractional, biodegradable and spectral characteristics which could be applied in specific usages. Copyright © 2012 Elsevier Ltd. All rights reserved.

Radiation-chemical sanitation of dissolved pollutants and environmental protection

International Nuclear Information System (INIS)

Petrukhin, N.V.; Putilov, A.V.

1986-01-01

Radiation-chemical sanitation of dissolved toxic pollutants resulted from the production processes of different substances and modern equipment operation is considered. The processes of fundamental industrial sewage processing and, as a result, features of practically total disposal of dissolved toxic agents are considered for the first time

Correlation between conductivity and total dissolved solid in various type of water: A review

Science.gov (United States)

Rusydi, Anna F.

2018-02-01

Conductivity (EC) and total dissolved solids (TDS) are water quality parameters, which are used to describe salinity level. These two parameters are correlated and usually expressed by a simple equation: TDS = k EC (in 25 °C). The process of obtaining TDS from water sample is more complex than that of EC. Meanwhile, TDS analysis is very important because it can illustrate groundwater quality, particularly in understanding the effect of seawater intrusion better than EC analysis. These conditions make research in revealing TDS/EC ratios interesting to do. By finding the ratio value, TDS concentration can be measured easily from EC value. However, the ratio cannot be defined easily. Previous research results have found that the correlation between TDS and EC are not always linear. The ratio is not only strongly influenced by salinity contents, but also by materials contents. Furthermore, the analysis of TDS concentration from EC value can be used to give an overview of water quality. For more precision, TDS concentrations need to be analyzed using the gravimetric method in the laboratory.

Mercury, monomethyl mercury, and dissolved organic carbon concentrations in surface water entering and exiting constructed wetlands treated with metal-based coagulants, Twitchell Island, California

Science.gov (United States)

Stumpner, Elizabeth B.; Kraus, Tamara E.C.; Fleck, Jacob A.; Hansen, Angela M.; Bachand, Sandra M.; Horwath, William R.; DeWild, John F.; Krabbenhoft, David P.; Bachand, Philip A.M.

2015-09-02

Coagulation with metal-based salts is a practice commonly employed by drinking-water utilities to decrease particle and dissolved organic carbon concentrations in water. In addition to decreasing dissolved organic carbon concentrations, the effectiveness of iron- and aluminum-based coagulants for decreasing dissolved concentrations both of inorganic and monomethyl mercury in water was demonstrated in laboratory studies that used agricultural drainage water from the Sacramento–San Joaquin Delta of California. To test the effectiveness of this approach at the field scale, nine 15-by-40‑meter wetland cells were constructed on Twitchell Island that received untreated water from island drainage canals (control) or drainage water treated with polyaluminum chloride or ferric sulfate coagulants. Surface-water samples were collected approximately monthly during November 2012–September 2013 from the inlets and outlets of the wetland cells and then analyzed by the U.S. Geological Survey for total concentrations of mercury and monomethyl mercury in filtered (less than 0.3 micrometers) and suspended-particulate fractions and for concentrations of dissolved organic carbon.

Biogeneration of chromophoric dissolved organic matter by bacteria and krill in the southern ocean

OpenAIRE

Ortega-Retuerta, E.; Frazer, Thomas K.; Duarte, Carlos M.; Ruiz-Halpern, Sergio; Tovar-Sánchez, Antonio; Arrieta López de Uralde, Jesús M.; Reche, Isabel

2009-01-01

Chromophoric dissolved organic matter (CDOM), the optically active fraction of dissolved organic matter, is primarily generated by pelagic organisms in the open ocean. In this study, we experimentally determined the quantity and spectral quality of CDOM generated by bacterioplankton using two different substrates (with and without photoproducts) and by Antarctic krill Euphausia superba and evaluated their potential contributions to CDOM dynamics in the peninsular region of the Southern Ocean....

Monitoring dissolved radioactive cesium in Abukuma River in Fukushima Prefecture

International Nuclear Information System (INIS)

Yasutaka, Tetsuo; Kawabe, Yoshishige; Kurosawa, Akihiko; Komai, Takeshi

2013-01-01

Radioactive materials were released into the atmosphere and deposited over wide areas of farmland, forests, and cities; elevated levels of "1"3"1I, "1"3"4Cs, and "1"3"7Cs have been detected in these areas due to the accident at the Tokyo Power Fukushima Daiichi Nuclear Power Plant caused by the April 2011 earthquake and tsunami in eastern Japan. Radioactive Cs deposited on farmland and forests gradually leaches into water bodies such as mountain streams and rivers adsorbed onto particles or in a dissolved state. It is important to calrify the level of dissolved and total radioactive Cs in environmental water for forecasting the of discharge of radioactive Cs from forest and watersheds, assessing on the effect of dissolved and total radioactive Cs on not only irrigation water but also rice and other crops, and evaluating the transport of radioactive Cs from rivers to costal areas. Therefore, it is important to monitor their levels in Fukushima Prefecture over time. In this research, we monitored the levels of dissolved and total radioactive Cs in Abukuma River using a conventional evaporative concentration method. By monitoring the river waters since September 2012, it was estimated that the levels of dissolved radioactive Cs were less than 0.128 Bq/L and those of total radioactive Cs were less than 0.274 Bq/L in the main stream and branches of Abukuma River in the low suspended solid condition. (author)

Isolation, purification and analysis of dissolved organic carbon from Gohagoda uncontrolled open dumpsite leachate, Sri Lanka.

Science.gov (United States)

Vithanage, Meththika; Wijesekara, Hasintha; Mayakaduwa, S S

2017-07-01

Extract and analysis of the Dissolved Organic Carbon (DOC) fractions were analyzed from the leachate of an uncontrolled dumpsite at Gohagoda, Sri Lanka. DOC fractions, humic acid (HA), fulvic acid (FA) and the hydrophilic (Hyd) fractions were isolated and purified with the resin techniques. Spectroscopic techniques and elemental analysis were performed to characterize DOCs. Maximum TOC and DOC values recorded were 56,955 and 28,493 mg/L, respectively. Based on the total amount of DOC fractionation, Hyd dominated accounting for ∼60%, and HA and FA constituted ∼22% and ∼17%, respectively, exhibiting the mature phase of the dumpsite. The elemental analysis of DOCs revealed carbon variation following HA > FA > Hyd, while hydrogen and nitrogen were similar in each fraction. The N/C ratio for HA was recorded as 0.18, following a similar trend in old dumpsite leachate elsewhere. The O/C ratios for HA and FA were recorded higher as much as 1.0 and 9.3, respectively, indicating high degree of carbon mineralization in the leachates. High content of carboxylic, phenolic and lactone groups in all DOCs was observed disclosing their potential for toxic substances transportation. The results strongly suggest the risk associated with DOCs in dumpsite leachate to the aquatic and terrestrial environment.

Characteristics of dissolved organic matter following 20 years of peatland restoration

NARCIS (Netherlands)

Höll, B.S.; Fiedler, S.; Jungkunst, H.F.; Kalbitz, K.; Freibauer, A.; Drösler, M.; Stahr, K.

2009-01-01

The changes in the amounts and composition of dissolved organic matter (DOM) following long-term peat restoration are unknown, although this fraction of soil organic matter affects many processes in such ecosystems. We addressed this lack of knowledge by investigating a peatland in south-west

Carbon-14 measurements and characterization of dissolved organic carbon in ground water

International Nuclear Information System (INIS)

Murphy, E.M.

1987-01-01

Carbon-14 was measured in the dissolved organic carbon (DOC) in ground water and compared with 14 C analyses of dissolved inorganic carbon (DIC). Two field sites were used for this study; the Stripa mine in central Sweden, and the Milk River Aquifer in southern Alberta, Canada. The Stripa mine consists of a Precambrian granite dominated by fracture flow, while the Milk River Aquifer is a Cretaceous sandstone aquifer characterized by porous flow. At both field sites, 14 C analyses of the DOC provide additional information on the ground-water age. Carbon-14 was measured on both the hydrophobic and hydrophilic organic fractions of the DOC. The organic compounds in the hydrophobic and hydrophilic fractions were also characterized. The DOC may originate from kerogen in the aquifer matrix, from soil organic matter in the recharge zone, of from a combination of these two sources. Carbon-14 analyses, along with characterization of the organics, were used to determine this origin. Carbon-14 analyses of the hydrophobic fraction in the Milk River Aquifer suggest a soil origin, while 14 C analyses of the hydrophilic fraction suggest an origin within the Cretaceous sediments (kerogen) or from the shale in contact with the aquifer

Voltammetric determination of total dissolved iron in coastal waters using a glassy carbon electrode modified with reduced graphene oxide, Methylene Blue and gold nanoparticles

International Nuclear Information System (INIS)

Lin, Mingyue; Zhang, Haiyun; Han, Haitao; Pan, Dawei; Su, Zhencui

2015-01-01

A nanocomposite, prepared from reduced graphene oxide (rGO), Methylene Blue (MB) and gold nanoparticles (AuNPs), was used to modify a glassy carbon electrode for the determination of total dissolved iron by differential pulse voltammetry. The use of rGO warrants a larger electrode surface and the presence of more active sites, while electron transfer is accelerated by incorporating AuNPs. MB acts as an electron mediator, as an anchor for the AuNPs (which were grown in situ), and also prevents the aggregation of rGO. The modified electrode displayed a remarkably improved sensitivity and selectivity for Fe(III). The kinetics of the electrode reaction is adsorption-controlled, and the reversible process involves one proton and one electron. The response to Fe(III) is linear in the 0.3 to 100 μM concentration range, and the detection limit is 15 nM. Possible interferences by other ions were studied. The electrode was successfully applied to the determination of total dissolved iron in real coastal waters. (author)

Determination of serum free thyroxine concentration (FT4) by means of fT4-fraction and total thyroxine concentration

International Nuclear Information System (INIS)

Passath, A.; Leb, G.

1985-01-01

A new equilibrium assay for the determination of serum free thyroxine was evaluated in 514 patients. The assay comprises a two-vial-procedure to measure total thyroxine and free thyroxine fraction by use of monoclonal antibodies. Free thyroxine concentrations are calculated from fT 4 -fraction and total thyroxine concentration readings. In euthyroidism the average free thyroxine fraction (%fT 4 ) was 0.011%, in hyperthyroidism this fraction was elevated, in hypothyroidism it was below normal. In patients with TBG anomalies, TBG values were inversely correlated with fT 4 fraction readings. The 'euthyroid reference range' of FT 4 (SPAC ET) was between 0.70 to 1.78ng/dl. This euthyroid range of FT 4 was determined from TT 4 concentrations measured by T 4 -RIA (SPAC T 4 MONO) which were 30% above TT 4 values measured by conventional T 4 -RIA (SPAC T 4 POLY; polyclonal antibodies). However, a different euthyroid range of FT 4 between 0.55 to 1.30 ng/dl was observed as well as by other investigators when conventional T 4 -RIA measurements were used for calculation of FT 4 values. Our results indicate that calculated FT 4 concentration values are highly dependent on the methods used for determination of total thyroxine concentrations. Precision and reproducability of this two vial equilibrium assay did not meet the requirements mandatory for the application as a clinical routine diagnostic procedure, and its general use for this purpose can as yet not be recommended. (Author)

Watershed scale spatial variability in dissolved and total organic and inorganic carbon in contrasting UK catchments

Science.gov (United States)

Cumberland, S.; Baker, A.; Hudson, N. J.

2006-12-01

Approximately 800 organic and inorganic carbon analyses have been undertaken from watershed scale and regional scale spatial surveys in various British catchments. These include (1) a small (urban catchment (Ouseburn, N England); (2) a headwater, lowland agricultural catchment (River Tern, C England) (3) a large UK catchment (River Tyne, ~3000 sq-km) and (4) a spatial survey of ~300 analyses from rivers from SW England (~1700 sq-km). Results demonstrate that: (1) the majority of organic and inorganic carbon is in the dissolved (DOC and DIC) fractions; (2) that with the exception of peat rich headwaters, DIC concentration is always greater than DOC; (3) In the rural River Tern, riverine DOC and DIC are shown to follow a simple end- member mixing between DIC (DOC) rich (poor) ground waters and DOC (DIC) rich (poor) riparian wetlands for all sample sites. (4) In the urbanized Ouseburn catchment, although many sample sites also show this same mixing trend, some tributaries follow a pollutant trend of simultaneous increases in both DOC and DIC. The Ouseburn is part of the larger Tyne catchment: this larger catchment follows the simple groundwater DIC- soil water DOC end member mixing model, with the exception of the urban catchments which exhibit an elevated DIC compared to rural sites. (5) Urbanization is demonstrated to increase DIC compared to equivalent rural catchments; this DIC has potential sources including diffuse source inputs from the dissolution of concrete, point sources such as trade effluents and landfill leachates, and bedrock derived carbonates relocated to the soil dissolution zone by urban development. (6) DIC in rural SW England demonstrates that spatial variability in DIC can be attributed to variations in geology; but that DIC concentrations in the SW England rivers dataset are typically lower than the urbanized Tyne catchments despite the presence of carbonate bedrock in many of the sample catchments in the SW England dataset. (7) Recent

A linear solvation energy relationship model of organic chemical partitioning to dissolved organic carbon.

Science.gov (United States)

Kipka, Undine; Di Toro, Dominic M

2011-09-01

Predicting the association of contaminants with both particulate and dissolved organic matter is critical in determining the fate and bioavailability of chemicals in environmental risk assessment. To date, the association of a contaminant to particulate organic matter is considered in many multimedia transport models, but the effect of dissolved organic matter is typically ignored due to a lack of either reliable models or experimental data. The partition coefficient to dissolved organic carbon (K(DOC)) may be used to estimate the fraction of a contaminant that is associated with dissolved organic matter. Models relating K(DOC) to the octanol-water partition coefficient (K(OW)) have not been successful for many types of dissolved organic carbon in the environment. Instead, linear solvation energy relationships are proposed to model the association of chemicals with dissolved organic matter. However, more chemically diverse K(DOC) data are needed to produce a more robust model. For humic acid dissolved organic carbon, the linear solvation energy relationship predicts log K(DOC) with a root mean square error of 0.43. Copyright © 2011 SETAC.

Iron isotopic fractionation during continental weathering

Energy Technology Data Exchange (ETDEWEB)

Fantle, Matthew S.; DePaolo, Donald J.

2003-10-01

The biological activity on continents and the oxygen content of the atmosphere determine the chemical pathways through which Fe is processed at the Earth's surface. Experiments have shown that the relevant chemical pathways fractionate Fe isotopes. Measurements of soils, streams, and deep-sea clay indicate that the {sup 56}Fe/{sup 54}Fe ratio ({delta}{sup 56}Fe relative to igneous rocks) varies from +1{per_thousand} for weathering residues like soils and clays, to -3{per_thousand} for dissolved Fe in streams. These measurements confirm that weathering processes produce substantial fractionation of Fe isotopes in the modern oxidizing Earth surface environment. The results imply that biologically-mediated processes, which preferentially mobilize light Fe isotopes, are critical to Fe chemistry in weathering environments, and that the {delta}{sup 56}Fe of marine dissolved Fe should be variable and negative. Diagenetic reduction of Fe in marine sediments may also be a significant component of the global Fe isotope cycle. Iron isotopes provide a tracer for the influence of biological activity and oxygen in weathering processes through Earth history. Iron isotopic fractionation during weathering may have been smaller or absent in an oxygen-poor environment such as that of the early Precambrian Earth.

Relative importance of dissolved and food pathways for lead contamination in shrimp

Energy Technology Data Exchange (ETDEWEB)

Boisson, F.; Cotret, O.; Teyssie, J.-L.; El-Baradeie, M.; Fowler, S.W

2003-12-01

% of total Pb retained and characterized by a turnover < 10 min, corresponded to lead weakly adsorbed on the exoskeleton and incorporated in the hepatopancreas. Nevertheless, a significant fraction of lead accumulated from the dissolved (2%) and food (52-57%) pathways remained irreversibly retained in the tissues, suggesting that this organism could also serve as an effective long-term bioindicator of lead contamination in marine waters.

Relative importance of dissolved and food pathways for lead contamination in shrimp

International Nuclear Information System (INIS)

Boisson, F.; Cotret, O.; Teyssie, J.-L.; El-Baradeie, M.; Fowler, S.W.

2003-01-01

The relative importance of dissolved and food pathways and the influence of food type in the bioaccumulation and retention of lead in the shrimp Palaemonetes varians were examined using a radiotracer method. Shrimp were exposed to 210 Pb-labelled seawater or fed two types of 210 Pb-labelled food, viz. mussels or worms. The amount of radiotracer accumulated by shrimp was examined over a 7-day period, followed by a 1-month and a 7-day depuration period for the dissolved and food source, respectively. Steady state in the uptake was reached after 2 days exposure to dissolved lead, with a resultant estimated concentration factor of 98 ± 3. Transfer factors following ingestion of contaminated mussels and worms were lower than unity for both food types, with lead transfer from worms being significantly higher than that from mussels. Accumulation of dissolved Pb by shrimp was found to occur mainly through adsorption on the exoskeleton with a minor accumulation in the internal tissues probably resulting from the intake of seawater for osmoregulation. In contrast, lead taken up from contaminated food was readily absorbed and bound in the internal tissues of P. varians. Although the transfer of lead to P. varians through the ingestion of contaminated food was low (TF < 1%), it still represented 4 to 8% of the lead content in the prey which is a significant additional contribution of lead to the shrimp body burden. Independent of food type, following ingestion of contaminated food, approximately 23-27% of total lead accumulated in shrimp was located in the edible parts (e.g. muscle). Therefore, the food pathway is suggested to be a significant contributor to the lead transfer to humans through ingestion of contaminated shrimp. After exposure to contaminated food, lead loss kinetics were described by a two-component model, whereas Pb loss following direct uptake from seawater was best described by a three-component model. The additional compartment representing 64% of total Pb

Relationships between colored dissolved organic matter and dissolved organic carbon in different coastal gradients of the Baltic Sea.

Science.gov (United States)

Harvey, E Therese; Kratzer, Susanne; Andersson, Agneta

2015-06-01

Due to high terrestrial runoff, the Baltic Sea is rich in dissolved organic carbon (DOC), the light-absorbing fraction of which is referred to as colored dissolved organic matter (CDOM). Inputs of DOC and CDOM are predicted to increase with climate change, affecting coastal ecosystems. We found that the relationships between DOC, CDOM, salinity, and Secchi depth all differed between the two coastal areas studied; the W Gulf of Bothnia with high terrestrial input and the NW Baltic Proper with relatively little terrestrial input. The CDOM:DOC ratio was higher in the Gulf of Bothnia, where CDOM had a greater influence on the Secchi depth, which is used as an indicator of eutrophication and hence important for Baltic Sea management. Based on the results of this study, we recommend regular CDOM measurements in monitoring programmes, to increase the value of concurrent Secchi depth measurements.

Characterization of Coconut Oil Fractions Obtained from Solvent Fractionation Using Acetone.

Science.gov (United States)

Sonwai, Sopark; Rungprasertphol, Poonyawee; Nantipipat, Nantinee; Tungvongcharoan, Satinee; Laiyangkoon, Nantikan

2017-09-01

This work was aimed to study the solvent fraction of coconut oil (CNO). The fatty acid and triacylglycerol compositions, solid fat content (SFC) and the crystallization properties of CNO and its solid and liquid fractions obtained from fractionation at different conditions were investigated using various techniques. CNO was dissolved in acetone (1:1 w/v) and left to crystallize isothermally at 10°C for 0.5, 1 and 2 h and at 12°C for 2, 3 and 6 h. The solid fractions contained significantly lower contents of saturated fatty acids of ≤ 10 carbon atoms but considerably higher contents of saturated fatty acids with > 12 carbon atoms with respect to those of CNO and the liquid fractions. They also contained higher contents of high-melting triacylglycerol species with carbon number ≥ 38. Because of this, the DSC crystallization onset temperatures and the crystallization peak temperatures of the solid fractions were higher than CNO and the liquid fractions. The SFC values of the solid fractions were significantly higher than CNO at all measuring temperatures before reaching 0% just below the body temperature with the fraction obtained at 12°C for 2 h exhibiting the highest SFC. On the contrary, the SFC values of the liquid fractions were lower than CNO. The crystallization duration exhibited strong influence on the solid fractions. There was no effect on the crystal polymorphic structure possibly because CNO has β'-2 as a stable polymorph. The enhanced SFC of the solid fractions would allow them to find use in food applications where a specific melting temperature is desired such as sophisticated confectionery fats, and the decreased SFC of the liquid fractions would provide them with a higher cold stability which would be useful during extended storage time.

Clinical and immunologic effects of fractionated total lymphoid irradiation in refractory rheumatoid arthritis

International Nuclear Information System (INIS)

Trentham, D.E.; Belli, J.A.; Anderson, R.J.; Buckley, J.A.; Goetzl, E.J.; David, J.R.; Austen, K.F.

1981-01-01

Ten patients with refractory rheumatoid arthritis were given 3000 rad of fractionated total lymphoid irradiation in an uncontrolled therapeutic trial. Total lymphoid irradiation was associated with objective evidence of considerable clinical improvement in eight patients and with reduced blood lymphocyte counts in all 10. On completion of irradiation, there was an abrogation of lymphocyte reactivity in vitro in the patients with clinical responses, but abnormal antibody activities characteristic of rheumatoid arthritis and normal components of humoral immunity were not suppressed. Partial recrudescence of arthritis occurred shortly after a year after the completion of irradiation and was paralleled by a restitution of lymphocyte concentrations and responsiveness to mitogens to levels similar to those observed before irradiation. These data provide further evidence of T-cell involvement in the pathogenesis of rheumatoid arthritis and demonstrate that total lymphoid irradiation can induce temporary relief, but they do not ascertain whether the natural history of this disease was altered

Clinical and immunologic effects of fractionated total lymphoid irradiation in refractory rheumatoid arthritis

International Nuclear Information System (INIS)

Trentham, D.E.; Belli, J.A.; Anderson, R.J.; Buckley, J.A.; Goetzl, E.J.; David, J.R.; Austen, K.F.

1981-01-01

Ten patients with refractory rheumatoid arthritis were given 3000 rad of fractionated total lymphoid irradiation in an uncontrolled therapeutic trial. Total lymphoid irradiation was associated with objective evidence of considerable clinical improvement in eight patients and with reduced blood lymphocyte counts in all 10. On completion of irradiation, there was an abrogation of lymphocyte reactivity in vitro in the patients with clinical responses, but abnormal antibody activities characteristic of rheumatoid arthritis and normal components of humoral immunity were not suppressed. Partial recrudescence of arthritis occurred shortly before a year after the completion of irradiation and was paralleled by a restitution of lymphocyte concentrations and responsiveness to mitogens to levels similar to those observed before irradiation. These data provide further evidence of T-cell involvement in the pathogenesis of rheumatoid arthritis and demonstrate that total lymphoid irradiation can induce temporary relief, but they do not ascertain whether the natural history of this disease was altered

Total body irradiation: current indications; L`irradiation corporelle totale: les indications actuelles

Energy Technology Data Exchange (ETDEWEB)

Giraud, P.; Danhier, S.; Dubray, B.; Cosset, J.M. [Institut Curie, 75 - Paris (France)

1998-05-01

The choice of dose and fractionation for total body irradiation is made difficult by the large number of considerations to be taken into account. The outcome of bone marrow transplantation after total body irradiation can be understood in terms of tumor cell killing, engraftment, and normal tissue damage, each of these endpoints being influenced by irradiation-, disease-, transplant-, and patient- related factors. Interpretation of clinical data is further hampered by the overwhelming influence of logistic constraints, the small numbers of randomized studies, and the concomitant variations in total dose and fraction size or dose rate. So far, three cautious conclusions can be drawn in order to tentatively adapt the total body irradiation schedule to clinically-relevant situations. Firstly, the organs at risk for normal tissue damage (lung, liver, lens, kidney) are protected by delivering small doses per fraction at low dose rate. This suggests that, when toxicity is at stake (e.g. in children), fractionated irradiation should be preferred, provided that inter-fraction intervals are long enough. Secondly, fractionated irradiation should be avoided in case of T-cell depleted transplant, given the high risk of graft rejection in this setting. An alternative would be to increase total (or fractional) dose of fractionated total body irradiation, but this approach is likely to induce more normal tissue toxicity. Thirdly, clinical data have shown higher relapse rates in chronic myeloid leukemia after fractionated or low dose rate total body irradiation, suggesting that fractionated irradiation should not be recommended, unless total (or fractional) dose is increased. Total body irradiation-containing regimens, primarily cyclophosphamide / total body irradiation, are either equivalent to or better than the chemotherapy-only regimens, primarily busulfan / cyclophosphamide. Busulfan / cyclophosphamide certainly represents a reasonable alternative, especially in patients who

Estimation of the Arterial Fraction of Total Hepatic Flow from Radionuclide Angiogram Using 99mTc-DISIDA

International Nuclear Information System (INIS)

Lee, Hae Gin; Lim, Gye Yeon; Yang, Il Kwon; Kim, Hack Hee; Lim, Jung Ik; Bahk, Yong Whee; Han, Sok Won; Han, Nam Ik; Lee, Young Sok

1991-01-01

Arterial fraction of total hepatic blood flow was estimated by a new method, slope method, on radionuclide angiogram using 99m Tc-DISIDA and was compared with that from 99m Tc-Phytate radionuclide angiogram. This study included 11 of normal subjects, 37 of intermediate group with various liver diseases, and 25 patients with liver cirrhosis. We analyzed the data with slope method from radionuclide angiograms and the results were compared with hepatic arterial fractions from uptake method, introduced by Lee et al. at 1986. The hepatic arterial fractions from radionuclide angiograms using 99m Tc-DISIDA and 99m Tc- Phytate were 0.32 ± 0.09 and 0.31 ± 0.11 respectively in normal subjects, and 0.75 ± 0.18 and 0.77 ± 0.21 respectively in patients with liver cirrhosis. The hepatic arterial fractions by the slope method was well correlated with those of the uptake method on 99m Tc-DISIDA scan. There was high correlation between the hepatic arterial fractions from 99m Tc-DISIDA and 99m Tc-Phytate scans. Hepatic arterial fraction estimated by the slope method is a useful index for the diagnosis of liver cirrhosis and the evaluation of status of portal hypertension.

High-dose total-body irradiation and autologous marrow reconstitution in dogs: dose-rate-related acute toxicity and fractionation-dependent long-term survival

International Nuclear Information System (INIS)

Deeg, H.J.; Storb, R.; Weiden, P.L.; Schumacher, D.; Shulman, H.; Graham, T.; Thomas, E.D.

1981-01-01

Beagle dogs treated by total-body irradiation (TBI) were given autologous marrow grafts in order to avoid death from marrow toxicity. Acute and delayed non-marrow toxicities of high single-dose (27 dogs) and fractionated TBI (20 dogs) delivered at 0.05 or 0.1 Gy/min were compared. Fractionated TBI was given in increments of 2 Gy every 6 hr for three increments per day. Acute toxicity and early mortality (<1 month) at identical total irradiation doses were comparable for dogs given fractionated or single-dose TBI. With single-dose TBI, 14, 16, and 18 Gy, respectively, given at 0.05 Gy/min, 0/5, 5/5, and 2/2 dogs died from acute toxicity; with 10, 12, and 14 Gy, respectively, given at 0.1 Gy/min, 1/5, 4/5, and 5/5 dogs died acutely. With fractionated TBI, 14 and 16 Gy, respectively, given at 0.1 Gy/min, 1/5, 4/5, and 2/2 dogs died auctely. Early deaths were due to radiation enteritis with or without associated septicemia (29 dogs; less than or equal to Day 10). Three dogs given 10 Gy of TBI at 0.1 Gy/min died from bacterial pneumonia; one (Day 18) had been given fractionated and two (Days 14, 22) single-dose TBI. Fifteen dogs survived beyond 1 month; eight of these had single-dose TBI (10-14 Gy) and all died within 7 months of irradiation from a syndrome consisting of hepatic damage, pancreatic fibrosis, malnutrition, wasting, and anemia. Seven of the 15 had fractionated TBI, and only one (14 Gy) died on Day 33 from hepatic failure, whereas 6 (10-14 Gy) are alive and well 250 to 500 days after irradiation. In conclusion, fractionated TBI did not offer advantages over single-dose TBI with regard to acute toxicity and early mortality; rather, these were dependent upon the total dose of TBI. The total acutely tolerated dose was dependent upon the exposure rate; however, only dogs given fractionated TBI became healthy long-term survivors

Dissolved organic carbon and chromophoric dissolved organic matter properties of rivers in the USA

Science.gov (United States)

Spencer, Robert G. M.; Butler, Kenna D.; Aiken, George R.

2012-09-01

Dissolved organic carbon (DOC) concentration and chromophoric dissolved organic matter (CDOM) parameters were measured over a range of discharge in 30 U.S. rivers, covering a diverse assortment of fluvial ecosystems in terms of watershed size and landscape drained. Relationships between CDOM absorption at a range of wavelengths (a254, a350, a440) and DOC in the 30 watersheds were found to correlate strongly and positively for the majority of U.S. rivers. However, four rivers (Colorado, Colombia, Rio Grande and St. Lawrence) exhibited statistically weak relationships between CDOM absorption and DOC. These four rivers are atypical, as they either drain from the Great Lakes or experience significant impoundment of water within their watersheds, and they exhibited values for dissolved organic matter (DOM) parameters indicative of autochthonous or anthropogenic sources or photochemically degraded allochthonous DOM and thus a decoupling between CDOM and DOC. CDOM quality parameters in the 30 rivers were found to be strongly correlated to DOM compositional metrics derived via XAD fractionation, highlighting the potential for examining DOM biochemical quality from CDOM measurements. This study establishes the ability to derive DOC concentration from CDOM absorption for the majority of U.S. rivers, describes characteristics of riverine systems where such an approach is not valid, and emphasizes the possibility of examining DOM composition and thus biogeochemical function via CDOM parameters. Therefore, the usefulness of CDOM measurements, both laboratory-based analyses and in situ instrumentation, for improving spatial and temporal resolution of DOC fluxes and DOM dynamics in future studies is considerable in a range of biogeochemical studies.

Dissolved organic carbon and chromophoric dissolved organic matter properties of rivers in the USA

Science.gov (United States)

Spencer, Robert G.M.; Butler, Kenna D.; Aiken, George R.

2012-01-01

Dissolved organic carbon (DOC) concentration and chromophoric dissolved organic matter (CDOM) parameters were measured over a range of discharge in 30 U.S. rivers, covering a diverse assortment of fluvial ecosystems in terms of watershed size and landscape drained. Relationships between CDOM absorption at a range of wavelengths (a254, a350, a440) and DOC in the 30 watersheds were found to correlate strongly and positively for the majority of U.S. rivers. However, four rivers (Colorado, Colombia, Rio Grande and St. Lawrence) exhibited statistically weak relationships between CDOM absorption and DOC. These four rivers are atypical, as they either drain from the Great Lakes or experience significant impoundment of water within their watersheds, and they exhibited values for dissolved organic matter (DOM) parameters indicative of autochthonous or anthropogenic sources or photochemically degraded allochthonous DOM and thus a decoupling between CDOM and DOC. CDOM quality parameters in the 30 rivers were found to be strongly correlated to DOM compositional metrics derived via XAD fractionation, highlighting the potential for examining DOM biochemical quality from CDOM measurements. This study establishes the ability to derive DOC concentration from CDOM absorption for the majority of U.S. rivers, describes characteristics of riverine systems where such an approach is not valid, and emphasizes the possibility of examining DOM composition and thus biogeochemical function via CDOM parameters. Therefore, the usefulness of CDOM measurements, both laboratory-based analyses and in situ instrumentation, for improving spatial and temporal resolution of DOC fluxes and DOM dynamics in future studies is considerable in a range of biogeochemical studies.

Molecular characterization of macrophyte-derived dissolved organic matters and their implications for lakes

Science.gov (United States)

Chemical properties of whole organic matter (OM) and its dissolved organic matter (DOM) fraction from six dominant macrophytes in Lake Dianchi were comparatively characterized, and their environmental implications were discussed. Significant differences in chemical composition of the OM samples were...

Total proteins and protein fractions levels in pregnant rats subjected to whole-body gamma irradiation

International Nuclear Information System (INIS)

Mansour, M.A.; Roushdy, H.M.; Mazhar, F.M.; Abu-Gabal, H.A.

1986-01-01

A total number of 180 mature rats (120 females and 60 males) weighing from 120-140 g were used to study the effect of two doses (2 and 4 Gy) whole-body gamma irradiation on the level of total protein and protein fractions in serum of pregnant rats during the period of organogenesis. It was found that the levels of total protein, albumin and gamma globulins significantly decreased according to the doses of exposure. The levels of alpha and beta globulins significantly increased more in the serum of rats exposed to 2 Gy than in rats exposed to 4 Gy. The level of A/G ratio significantly decreased more in the serum of rats exposed to 2Gy than in those exposed to 4 Gy

Elucidating mechanisms of toxic action of dissolved organic chemicals in oil sands process-affected water (OSPW).

Science.gov (United States)

Morandi, Garrett D; Wiseman, Steve B; Guan, Miao; Zhang, Xiaowei W; Martin, Jonathan W; Giesy, John P

2017-11-01

Oil sands process-affected water (OSPW) is generated during extraction of bitumen in the surface-mining oil sands industry in Alberta, Canada, and is acutely and chronically toxic to aquatic organisms. It is known that dissolved organic compounds in OSPW are responsible for most toxic effects, but knowledge of the specific mechanism(s) of toxicity, is limited. Using bioassay-based effects-directed analysis, the dissolved organic fraction of OSPW has previously been fractionated, ultimately producing refined samples of dissolved organic chemicals in OSPW, each with distinct chemical profiles. Using the Escherichia coli K-12 strain MG1655 gene reporter live cell array, the present study investigated relationships between toxic potencies of each fraction, expression of genes and characterization of chemicals in each of five acutely toxic and one non-toxic extract of OSPW derived by use of effects-directed analysis. Effects on expressions of genes related to response to oxidative stress, protein stress and DNA damage were indicative of exposure to acutely toxic extracts of OSPW. Additionally, six genes were uniquely responsive to acutely toxic extracts of OSPW. Evidence presented supports a role for sulphur- and nitrogen-containing chemical classes in the toxicity of extracts of OSPW. Copyright © 2017 Elsevier Ltd. All rights reserved.

Dissolved inorganic carbon, total alkalinity, pH, phosphate, dissolved oxygen, and other variables collected from surface discrete observations using Niksin bottle and other instruments from R/V Sultana in the southwest coast of Puerto Rico from 2009-01-05 to 2016-02-01 (NCEI Accession 0145164)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This time series dataset includes weekly and bi-weekly discrete seawater samples of pH and total alkalinity, dissolved inorganic carbon, phosphates and profile...

Iron traps terrestrially derived dissolved organic matter at redox interfaces

Science.gov (United States)

Riedel, Thomas; Zak, Dominik; Biester, Harald; Dittmar, Thorsten

2013-01-01

Reactive iron and organic carbon are intimately associated in soils and sediments. However, to date, the organic compounds involved are uncharacterized on the molecular level. At redox interfaces in peatlands, where the biogeochemical cycles of iron and dissolved organic matter (DOM) are coupled, this issue can readily be studied. We found that precipitation of iron hydroxides at the oxic surface layer of two rewetted fens removed a large fraction of DOM via coagulation. On aeration of anoxic fen pore waters, >90% of dissolved iron and 27 ± 7% (mean ± SD) of dissolved organic carbon were rapidly (within 24 h) removed. Using ultra-high-resolution MS, we show that vascular plant-derived aromatic and pyrogenic compounds were preferentially retained, whereas the majority of carboxyl-rich aliphatic acids remained in solution. We propose that redox interfaces, which are ubiquitous in marine and terrestrial settings, are selective yet intermediate barriers that limit the flux of land-derived DOM to oceanic waters. PMID:23733946

An asymptotic analytical solution to the problem of two moving boundaries with fractional diffusion in one-dimensional drug release devices

International Nuclear Information System (INIS)

Yin Chen; Xu Mingyu

2009-01-01

We set up a one-dimensional mathematical model with a Caputo fractional operator of a drug released from a polymeric matrix that can be dissolved into a solvent. A two moving boundaries problem in fractional anomalous diffusion (in time) with order α element of (0, 1] under the assumption that the dissolving boundary can be dissolved slowly is presented in this paper. The two-parameter regular perturbation technique and Fourier and Laplace transform methods are used. A dimensionless asymptotic analytical solution is given in terms of the Wright function

Total body irradiation in bone marrow transplantation: the influence of fractionation and delay of marrow infusion

International Nuclear Information System (INIS)

Lichter, A.S.; Tracy, D.; Lam, W.C.; Order, S.E.

1980-01-01

Bone marrow transplantation (BMT) after total body irradiation (TBI) and cyclophosphamide is being employed increasingly in the therapy of end stage leukemia. Interstitial pneumonitis (IP) represents a major acute toxicity after allogeneic transplantation. A more rapid reconstitution of lymphoid organs and bone marrow post transplant may result in increased immune competence and hence fewer opportunistic pulmonary infections and IP. By delaying the infusion of marrow to 72 hr after TBI (1250 rad at 7.5 rad/min) instead of the customary 24 hr, we can demonstrate an increase in initial repopulation of thymus, spleen and bone marrow, with syngeneic transplants in Lewis rats. Interstitial pneumonitis may also be caused, in part, by the pulmonary toxicity of large single exposures of TBI. Clinical and laboratory data suggest that fractionated TBI may be less toxic to the lung. When fractionated TBI (625 rad x 2, 7.5 rad/min) is compared to single dose TBI (1250 rad, 7.5 rad/min), and increased initial repopulation of lymphoid organs is observed when fractionated therapy is employed. Delay in marrow infusion and fractionation of TBI exposure may have clinical advantages in patients who receive BMT

Chromophoric dissolved organic matter in experimental mesocosms maintained under different pCO2 levels

OpenAIRE

Rochelle-Newall, E.; Delille, B.; Frankignoulle, M.; Gattuso, J.-P.; Jacquet, S.; Riebesell, Ulf; Terbrüggen, A.; Zondervan, I.

2004-01-01

Chromophoric dissolved organic matter (CDOM) represents the optically active fraction of the bulk dissolved organic matter (DOM) pool. Recent evidence pointed towards a microbial source of CDOM in the aquatic environment and led to the proposal that phytoplankton is not a direct source of CDOM, but that heterotrophic bacteria, through reprocessing of DOM of algal origin, are an important source of CDOM. In a recent experiment designed at looking at the effects of elevated pCO2 on blooms of th...

Total Dissolved Gas Effects on Incubating Chum Salmon Below Bonneville Dam

Energy Technology Data Exchange (ETDEWEB)

Arntzen, Evan V.; Hand, Kristine D.; Carter, Kathleen M.; Geist, David R.; Murray, Katherine J.; Dawley, Earl M.; Cullinan, Valerie I.; Elston, Ralph A.; Vavrinec, John

2009-01-29

At the request of the U.S. Army Corps of Engineers (USACE; Portland District), Pacific Northwest National Laboratory (PNNL) undertook a project in 2006 to look further into issues of total dissolved gas (TDG) supersaturation in the lower Columbia River downstream of Bonneville Dam. In FY 2008, the third year of the project, PNNL conducted field monitoring and laboratory toxicity testing to both verify results from 2007 and answer some additional questions about how salmonid sac fry respond to elevated TDG in the field and the laboratory. For FY 2008, three objectives were 1) to repeat the 2006-2007 field effort to collect empirical data on TDG from the Ives Island and Multnomah Falls study sites; 2) to repeat the static laboratory toxicity tests on hatchery chum salmon fry to verify 2007 results and to expose wild chum salmon fry to incremental increases in TDG, above those of the static test, until external symptoms of gas bubble disease were clearly present; and 3) to assess physiological responses to TDG levels in wild chum salmon sac fry incubating below Bonneville Dam during spill operations. This report summarizes the tasks conducted and results obtained in pursuit of the three objectives. Chapter 1 discusses the field monitoring, Chapter 2 reports the findings of the laboratory toxicity tests, and Chapter 3 describes the field-sampling task. Each chapter contains an objective-specific introduction, description of the study site and methods, results of research, and discussion of findings. Literature cited throughout this report is listed in Chapter 4. Additional details on the monitoring methodology and results are provided in Appendices A and B included on the compact disc bound inside the back cover of the printed version of this report.

Software quality assurance plan for void fraction instrument

International Nuclear Information System (INIS)

Gimera, M.

1994-01-01

Waste Tank SY-101 has been the focus of extensive characterization work over the past few years. The waste continually generates gases, most notably hydrogen, which are periodically released from the waste. Gas can be trapped in tank waste in three forms: as void gas (bubbles), dissolved gas, or absorbed gas. Void fraction is the volume percentage of a given sample that is comprised of void gas. The void fraction instrument (VFI) acquires the data necessary to calculate void fraction. This document covers the product, Void Fraction Data Acquisition Software. The void fraction software being developed will have the ability to control the void fraction instrument hardware and acquire data necessary to calculate the void fraction in samples. This document provides the software quality assurance plan, verification and validation plan, and configuration management plan for developing the software for the instrumentation that will be used to obtain void fraction data from Tank SY-101

Design and Implementation of Remotely Monitoring System for Total Dissolved Solid in Baghdad Drinking Water Networks

Directory of Open Access Journals (Sweden)

Hussein Abdul-Ridha Mohammed

2018-01-01

Full Text Available he pollution of drinking water is a dangerous problem for the whole world, it can threaten the health of people and as people in developed society attaches more importance to environmental protection, it is of great research significance to intelligently and remotely monitoring the environment. Therefore in this paper, a remote water monitoring system for Baghdad drinking water system is suggested. The proposed system consists of data sensing and monitoring nodes at different locations in Baghdad to sensing and analyzes the data. These nodes are periodically measured Total Dissolved Solids (TDS. In case of measured value above TDS threshold which is 500 ppm, then an automated warning message will be sent to authorize persons in the maintenance center via Global Position System to take the correct action. This suggested structure has several advantages over traditional monitoring systems in terms of price, portability, reliability, applicability and takes a sample from a water tap in easy and real-time approach.

Reductions of dissolved organic matter and disinfection by-product precursors in full-scale wastewater treatment plants in winter.

Science.gov (United States)

Xue, Shuang; Jin, Wujisiguleng; Zhang, Zhaohong; Liu, Hong

2017-07-01

The reductions of dissolved organic matter (DOM) and disinfection byproduct precursors in four full-scale wastewater treatment plants (WWTPs) (Liaoning Province, China) where different biological treatment processes were employed in winter were investigated. The total removal efficiencies of dissolved organic carbon (DOC), ultraviolet light at 254 nm (UV-254), trihalomethane formation potential (THMFP), and haloacetic acid formation potential (HAAFP) were in the range of 70.3-76.0%, 49.6-57.3%, 54.4-65.0%, and 53.7-63.8% in the four WWTPs, respectively. The biological treatment was the predominant process responsible for the removal of DOC, THMFP, and HAAFP in WWTPs. Differences in the reduction of UV-254 were not significant (p > 0.05) among biochemical reaction pool, secondary sedimentation tank, and disinfection tank. Biological aerated filter and suspended carrier activated sludge processes achieved higher DOM removal than the conventional active sludge and anaerobic-anoxic-oxic processes. Hydrophobic neutral and hydrophilic fraction were removed to a higher degree through biological treatment than the other three DOM fractions. HAAFP removal was more efficient than THMFP reduction during biological treatment. During primary treatment, fluorescent materials in secondary sedimentation tanks were preferentially removed, as compared to the bulk DOM. Humic-like fluorescent compounds were not readily eliminated during biological treatment. The fluorescent materials were more susceptible to chlorine than nonfluorescent compounds. Copyright © 2017. Published by Elsevier Ltd.

Cytogenetic studies on recipients of allogeneic bone marrow transplants after fractionated total body irradiation

Energy Technology Data Exchange (ETDEWEB)

Schmitz, N; Goedde-Salz, E; Loeffler, H [Christian-Albrechts-Univ., Kiel (Germany, F.R.)

1985-06-01

Cytogenetic findings from the bone marrow (BM) and the peripheral blood (PB) of nine consecutive patients after allogeneic bone marrow transplantation (BMT) for acute or chronic myelogenous leukaemia are reported. After a conditioning regimen consisting of cyclophosphamide and fractionated total body irradiation (TBI) given in five or six fractions of 2 Gy, persistence of host cells was detected in four out of seven cases with permanent engraftment. While one of these patients relapsed 4 months after host cells had been found in BM and PB, the other patients stayed relapse-free 124, 257 and 347 d after grafting. Before transplantation, the leukaemic cells in all three cases carried unique cytogenetic abnormalities giving the opportunity to distinguish the leukaemic population from chromosomally non-aberrant cells thought to represent residual normal host cells. As the persisting host cells after BMT lacked any cytogenetic abnormalities, it is suggested that they were members of residual normal clones not involved in the leukaemic process.

Cytogenetic studies on recipients of allogeneic bone marrow transplants after fractionated total body irradiation

International Nuclear Information System (INIS)

Schmitz, N.; Goedde-Salz, E.; Loeffler, H.

1985-01-01

Cytogenetic findings from the bone marrow (BM) and the peripheral blood (PB) of nine consecutive patients after allogeneic bone marrow transplantation (BMT) for acute or chronic myelogenous leukaemia are reported. After a conditioning regimen consisting of cyclophosphamide and fractionated total body irradiation (TBI) given in five or six fractions of 2 Gy, persistence of host cells was detected in four out of seven cases with permanent engraftment. While one of these patients relapsed 4 months after host cells had been found in BM and PB, the other patients stayed relapse-free 124, 257 and 347 d after grafting. Before transplantation, the leukaemic cells in all three cases carried unique cytogenetic abnormalities giving the opportunity to distinguish the leukaemic population from chromosomally non-aberrant cells thought to represent residual normal host cells. As the persisting host cells after BMT lacked any cytogenetic abnormalities, it is suggested that they were members of residual normal clones not involved in the leukaemic process. (author)

COMMERCIAL SNF ACCIDENT RELEASE FRACTIONS

Energy Technology Data Exchange (ETDEWEB)

S.O. Bader

1999-10-18

The purpose of this design analysis is to specify and document the total and respirable fractions for radioactive materials that are released from an accident event at the Monitored Geologic Repository (MGR) involving commercial spent nuclear fuel (CSNF) in a dry environment. The total and respirable release fractions will be used to support the preclosure licensing basis for the MGR. The total release fraction is defined as the fraction of total CSNF assembly inventory, typically expressed as an activity inventory (e.g., curies), of a given radionuclide that is released to the environment from a waste form. The radionuclides are released from the inside of breached fuel rods (or pins) and from the detachment of radioactive material (crud) from the outside surfaces of fuel rods and other components of fuel assemblies. The total release fraction accounts for several mechanisms that tend to retain, retard, or diminish the amount of radionuclides that are available for transport to dose receptors or otherwise can be shown to reduce exposure of receptors to radiological releases. The total release fraction includes a fraction of airborne material that is respirable and could result in inhalation doses. This subset of the total release fraction is referred to as the respirable release fraction. Potential accidents may involve waste forms that are characterized as either bare (unconfined) fuel assemblies or confined fuel assemblies. The confined CSNF assemblies at the MGR are contained in shipping casks, canisters, or disposal containers (waste packages). In contrast to the bare fuel assemblies, the container that confines the fuel assemblies has the potential of providing an additional barrier for diminishing the total release fraction should the fuel rod cladding breach during an accident. However, this analysis will not take credit for this additional bamer and will establish only the total release fractions for bare unconfined CSNF assemblies, which may however be

COMMERCIAL SNF ACCIDENT RELEASE FRACTIONS

International Nuclear Information System (INIS)

S.O. Bader

1999-01-01

The purpose of this design analysis is to specify and document the total and respirable fractions for radioactive materials that are released from an accident event at the Monitored Geologic Repository (MGR) involving commercial spent nuclear fuel (CSNF) in a dry environment. The total and respirable release fractions will be used to support the preclosure licensing basis for the MGR. The total release fraction is defined as the fraction of total CSNF assembly inventory, typically expressed as an activity inventory (e.g., curies), of a given radionuclide that is released to the environment from a waste form. The radionuclides are released from the inside of breached fuel rods (or pins) and from the detachment of radioactive material (crud) from the outside surfaces of fuel rods and other components of fuel assemblies. The total release fraction accounts for several mechanisms that tend to retain, retard, or diminish the amount of radionuclides that are available for transport to dose receptors or otherwise can be shown to reduce exposure of receptors to radiological releases. The total release fraction includes a fraction of airborne material that is respirable and could result in inhalation doses. This subset of the total release fraction is referred to as the respirable release fraction. Potential accidents may involve waste forms that are characterized as either bare (unconfined) fuel assemblies or confined fuel assemblies. The confined CSNF assemblies at the MGR are contained in shipping casks, canisters, or disposal containers (waste packages). In contrast to the bare fuel assemblies, the container that confines the fuel assemblies has the potential of providing an additional barrier for diminishing the total release fraction should the fuel rod cladding breach during an accident. However, this analysis will not take credit for this additional bamer and will establish only the total release fractions for bare unconfined CSNF assemblies, which may however be

Methylmercury speciation in the dissolved phase of a stratified lake using the diffusive gradient in thin film technique

Energy Technology Data Exchange (ETDEWEB)

Clarisse, Olivier [Trent University, Department of Chemistry, 1600 West Bank Drive, Peterborough, Ontario K9J 7B8 (Canada)], E-mail: olivier.clarisse@umoncton.ca; Foucher, Delphine; Hintelmann, Holger [Trent University, Department of Chemistry, 1600 West Bank Drive, Peterborough, Ontario K9J 7B8 (Canada)

2009-03-15

The diffusive gradient in thin film (DGT) technique was successfully used to monitor methylmercury (MeHg) speciation in the dissolved phase of a stratified boreal lake, Lake 658 of the Experimental Lakes Area (ELA) in Ontario, Canada. Water samples were conventionally analysed for MeHg, sulfides, and dissolved organic matter (DOM). MeHg accumulated by DGT devices was compared to MeHg concentration measured conventionally in water samples to establish MeHg speciation. In the epilimnion, MeHg was almost entirely bound to DOM. In the top of the hypolimnion an additional labile fraction was identified, and at the bottom of the lake a significant fraction of MeHg was potentially associated to colloidal material. As part of the METAALICUS project, isotope enriched inorganic mercury was applied to Lake 658 and its watershed for several years to establish the relationship between atmospheric Hg deposition and Hg in fish. Little or no difference in MeHg speciation in the dissolved phase was detected between ambient and spike MeHg. - Methylmercury speciation was determined in the dissolved phase of a stratified lake using the diffusive gradient in thin film technique.

Methylmercury speciation in the dissolved phase of a stratified lake using the diffusive gradient in thin film technique

International Nuclear Information System (INIS)

Clarisse, Olivier; Foucher, Delphine; Hintelmann, Holger

2009-01-01

The diffusive gradient in thin film (DGT) technique was successfully used to monitor methylmercury (MeHg) speciation in the dissolved phase of a stratified boreal lake, Lake 658 of the Experimental Lakes Area (ELA) in Ontario, Canada. Water samples were conventionally analysed for MeHg, sulfides, and dissolved organic matter (DOM). MeHg accumulated by DGT devices was compared to MeHg concentration measured conventionally in water samples to establish MeHg speciation. In the epilimnion, MeHg was almost entirely bound to DOM. In the top of the hypolimnion an additional labile fraction was identified, and at the bottom of the lake a significant fraction of MeHg was potentially associated to colloidal material. As part of the METAALICUS project, isotope enriched inorganic mercury was applied to Lake 658 and its watershed for several years to establish the relationship between atmospheric Hg deposition and Hg in fish. Little or no difference in MeHg speciation in the dissolved phase was detected between ambient and spike MeHg. - Methylmercury speciation was determined in the dissolved phase of a stratified lake using the diffusive gradient in thin film technique

Feasibility study for evaluating cumulative exposure of downstream migrant juvenile salmonids to total dissolved gas. Final report

International Nuclear Information System (INIS)

Abernethy, C.S.; Dauble, D.D.; Johnson, R.L.

1997-11-01

A feasibility study was initiated to determine if downstream migrant salmonids could be monitored to determine potential relationships between total dissolved gas (TDG) exposure and signs of gas bubble trauma (GBT). The primary objectives were to: (1) establish logistical requirements for in-river monitoring of TDG exposure, including net pen design, deployment, and navigation constraints; (2) resolve uncertainties associated with effects of the net pen on fish behavior; (3) test the accuracy and precision of in-river monitoring equipment used to measure fish distribution and water quality; and (4) determine the application of hydrologic/flow models to predictions of TDG exposure. In-river measurements included water velocity, boat position, and selected water quality parameters (temperature, dissolved oxygen, pH, depth, conductivity). Fish distribution within the net pen was monitored using scanning sonar, and a split-beam echo sounder was used to evaluate vertical distribution of fish m in the river adjacent to the net pen. Three test drifts were conducted from late July through late August. The studies demonstrated that it was feasible to assemble and deploy a large net pen for mobile monitoring of TDG exposure. Accurate monitoring of vertical and lateral distribution of smolts was performed, and diel differences in behavior were documented. Further, the fish sounded in response to researcher activity on the perimeter platform. Thus, in-transit monitoring for GBT or mortality would affect fish depth distribution and exposure to TDG. Principal recommendations for future studies are directed at improving maneuverability of the net pen in adverse weather conditions and applying new acoustics technology to simultaneously collect fish distribution data from within and outside of the pen. 6 refs., 17 figs., 2 tabs

Weathering and vegetation controls on nickel isotope fractionation in surface ultramafic environments (Albania)

Science.gov (United States)

Estrade, Nicolas; Cloquet, Christophe; Echevarria, Guillaume; Sterckeman, Thibault; Deng, Tenghaobo; Tang, YeTao; Morel, Jean-Louis

2015-08-01

The dissolved nickel (Ni) isotopic composition of rivers and oceans presents an apparent paradox. Even though rivers represent a major source of Ni in the oceans, seawater is more enriched in the heavier isotopes than river-water. Additional sources or processes must therefore be invoked to account for the isotopic budget of dissolved Ni in seawater. Weathering of continental rocks is thought to play a major role in determining the magnitude and sign of isotopic fractionation of metals between a rock and the dissolved product. We present a study of Ni isotopes in the rock-soil-plant systems of several ultramafic environments. The results reveal key insights into the magnitude and the control of isotopic fractionation during the weathering of continental ultramafic rocks. This study introduces new constraints on the influence of vegetation during the weathering process, which should be taken into account in interpretations of the variability of Ni isotopes in rivers. The study area is located in a temperate climate zone within the ophiolitic belt area of Albania. The serpentinized peridotites sampled present a narrow range of heavy Ni isotopic compositions (δ60Ni = 0.25 ± 0.16 ‰, 2SD n = 2). At two locations, horizons within two soil profiles affected by different degrees of weathering all presented light isotopic compositions compared to the parent rock (Δ60Nisoil-rock up to - 0.63 ‰). This suggests that the soil pool takes up the light isotopes, while the heavier isotopes remain in the dissolved phase. By combining elemental and mineralogical analyses with the isotope compositions determined for the soils, the extent of fractionation was found to be controlled by the secondary minerals formed in the soil. The types of vegetation growing on ultramafic-derived soils are highly adapted and include both Ni-hyperaccumulating species, which can accumulate several percent per weight of Ni, and non-accumulating species. Whole-plant isotopic compositions were found

Assessment of pesticide availability in soil fractions after the incorporation of winery-distillery vermicomposts.

Science.gov (United States)

Fernández-Bayo, J D; Romero, E; Schnitzler, F; Burauel, P

2008-07-01

The influence of two vermicomposts from winery and distillery wastes on the distribution of diuron in agricultural soil was studied. Physical soil fractionations at 0, 9, 27, 49 and 77 days, allowed the quantification of pesticide residues in different particle-size fractions, coarse waste (WF), sand-sized (SF), silt-sized (SiF), clay-sized (CF) and dissolved organic matter-sized fraction (DOM). The SiF made a greater contribution to the formation of non-extractable residues in unamended soil, but when vermicomposts were added, new sorption sites in WF appeared, being higher for the more humified vermicompost V2. The dissolved organic carbon (DOC) increased with the addition of vermicompost, but the concentration of the desorbed 14C-radiochemical did not increase. Non-significant increment was observed with time for the non-extractable fraction with amendments. Diuron was transformed in all samples, although less than 0.5% was mineralized. The main effect caused by vermicomposts was a reduction in the availability of diuron in soil.

Mercury and Dissolved Organic Matter Dynamics During Snowmelt in the Upper Provo River, Utah, USA

Science.gov (United States)

Packer, B. N.; Carling, G. T.; Nelson, S.; Aanderud, Z.; Shepherd Barkdull, N.; Gabor, R. S.

2017-12-01

Mercury (Hg) is deposited to mountains by atmospheric deposition and mobilized during snowmelt runoff, leading to Hg contamination in otherwise pristine watersheds. Mercury is typically transported with dissolved organic matter (DOM) from soils to streams and lakes. This study focused on Hg and DOM dynamics in the snowmelt-dominated upper Provo River watershed, northern Utah, USA. We sampled Hg, dissolved organic carbon (DOC) concentrations, and DOM fluorescence in river water, snowpack, and ephemeral streams over four years from 2014-2017 to investigate Hg transport mechanisms. During the snowmelt season (April through June), Hg concentrations typically increased from 1 to 8 ng/L showing a strong positive correlation with DOC. The dissolved Hg fraction was dominant in the river, averaging 75% of total Hg concentrations, suggesting that DOC is more important for transport than suspended particulate matter. Ephemeral channels, which represent shallow flow paths with strong interactions with soils, had the highest Hg (>10 ng/L) and DOC (>10 mg/L) concentrations, suggesting a soil water source of Hg and organic matter. Fluorescence spectroscopy results showed important changes in DOM type and quality during the snowmelt season and the soil water flow paths are activated. Changes in DOM characteristics during snowmelt improve the understanding of Hg dynamics with organic matter and elucidate transport pathways from the soil surface, ephemeral channels and groundwater to the Provo River. This study has implications for understanding Hg sources and transport mechanisms in mountain watersheds.

Commercial SNF Accident Release Fractions

Energy Technology Data Exchange (ETDEWEB)

J. Schulz

2004-11-05

The purpose of this analysis is to specify and document the total and respirable fractions for radioactive materials that could be potentially released from an accident at the repository involving commercial spent nuclear fuel (SNF) in a dry environment. The total and respirable release fractions are used to support the preclosure licensing basis for the repository. The total release fraction is defined as the fraction of total commercial SNF assembly inventory, typically expressed as an activity inventory (e.g., curies), of a given radionuclide that is released to the environment from a waste form. Radionuclides are released from the inside of breached fuel rods (or pins) and from the detachment of radioactive material (crud) from the outside surfaces of fuel rods and other components of fuel assemblies. The total release fraction accounts for several mechanisms that tend to retain, retard, or diminish the amount of radionuclides that are available for transport to dose receptors or otherwise can be shown to reduce exposure of receptors to radiological releases. The total release fraction includes a fraction of airborne material that is respirable and could result in inhalation doses; this subset of the total release fraction is referred to as the respirable release fraction. Accidents may involve waste forms characterized as: (1) bare unconfined intact fuel assemblies, (2) confined intact fuel assemblies, or (3) canistered failed commercial SNF. Confined intact commercial SNF assemblies at the repository are contained in shipping casks, canisters, or waste packages. Four categories of failed commercial SNF are identified: (1) mechanically and cladding-penetration damaged commercial SNF, (2) consolidated/reconstituted assemblies, (3) fuel rods, pieces, and debris, and (4) nonfuel components. It is assumed that failed commercial SNF is placed into waste packages with a mesh screen at each end (CRWMS M&O 1999). In contrast to bare unconfined fuel assemblies, the

Commercial SNF Accident Release Fractions

International Nuclear Information System (INIS)

Schulz, J.

2004-01-01

The purpose of this analysis is to specify and document the total and respirable fractions for radioactive materials that could be potentially released from an accident at the repository involving commercial spent nuclear fuel (SNF) in a dry environment. The total and respirable release fractions are used to support the preclosure licensing basis for the repository. The total release fraction is defined as the fraction of total commercial SNF assembly inventory, typically expressed as an activity inventory (e.g., curies), of a given radionuclide that is released to the environment from a waste form. Radionuclides are released from the inside of breached fuel rods (or pins) and from the detachment of radioactive material (crud) from the outside surfaces of fuel rods and other components of fuel assemblies. The total release fraction accounts for several mechanisms that tend to retain, retard, or diminish the amount of radionuclides that are available for transport to dose receptors or otherwise can be shown to reduce exposure of receptors to radiological releases. The total release fraction includes a fraction of airborne material that is respirable and could result in inhalation doses; this subset of the total release fraction is referred to as the respirable release fraction. Accidents may involve waste forms characterized as: (1) bare unconfined intact fuel assemblies, (2) confined intact fuel assemblies, or (3) canistered failed commercial SNF. Confined intact commercial SNF assemblies at the repository are contained in shipping casks, canisters, or waste packages. Four categories of failed commercial SNF are identified: (1) mechanically and cladding-penetration damaged commercial SNF, (2) consolidated/reconstituted assemblies, (3) fuel rods, pieces, and debris, and (4) nonfuel components. It is assumed that failed commercial SNF is placed into waste packages with a mesh screen at each end (CRWMS M andO 1999). In contrast to bare unconfined fuel assemblies, the

Characterization of dissolved organic matter in landfill leachate during the combined treatment process of air stripping, Fenton, SBR and coagulation

Energy Technology Data Exchange (ETDEWEB)

Liu, ZhiPing, E-mail: liulqs@163.com [Key Laboratory of Three Gorges Reservoir Region’s Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045 (China); Faculty of Urban Construction and Environmental Engineering, Chongqing University, Chongqing 400020 (China); Wu, WenHui; Shi, Ping [Faculty of Urban Construction and Environmental Engineering, Chongqing University, Chongqing 400020 (China); Guo, JinSong [Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400045 (China); Cheng, Jin [Faculty of Urban Construction and Environmental Engineering, Chongqing University, Chongqing 400020 (China)

2015-07-15

Highlights: • DOM fractions spectra analysis during the whole treatment process. • Efficient method was achieved to remove organic matters in landfill leachate. • Molecular weight distribution and fractions were discussed. - Abstract: A combined treatment process of air stripping + Fenton + sequencing batch reactor (SBR)+ coagulation was performed to remove the pollutants in landfill leachate. Molecular weight (MW) distribution and fractions of dissolved organic matter (DOM) were discussed to study the characteristics. The experiment showed that the removal rate of chemical oxygen demand (COD), five day biological oxygen demand (BOD{sub 5}) and ammonia nitrogen (NH{sub 3}−N) by the combined process were 92.8%, 87.8% and 98.0%, respectively. Humic acid (HA) and fulvic acid (FA) were the main fractions in raw leachate with 81.8% of the total COD concentration, while hydrophilic organic matter (HyI) was the dominant fraction in the final effluent of the combined process with 63.5% of the total COD concentration. After the combined treatment process, the removal rate of DOM and fractions HA, FA, HyI were 91.9%, 97.1%, 95.8% and 71.7%, respectively. Organic matters of MW < 2 k and MW > 100 k were removed with 90.5% and 97.9% COD concentration after the treatment. The ultraviolet–visible spectra (UV–vis), Fourier transform infrared spectra (FTIR) and three-dimensional excitation-emission matrices spectra (EEMs) indicated that benzene materials and phenol compounds were preferentially removed in air stripping. High MW matters, aromatic rings, conjugated moieties and some functional groups were mainly removed by Fenton. While small MW fractions, carboxylic acids, alcohols and protein-like materials were preferentially biodegraded via SBR. Fulvic-like and humic-like materials were mainly destroyed via Fenton oxidation and coagulation.

A flow injection analyser conductometric coupled system for the field analysis of free dissolved CO{sub 2} and total dissolved inorganic carbon in natural waters

Energy Technology Data Exchange (ETDEWEB)

Martinotti, Valter; Balordi, Marcella; Ciceri, Giovanni [RSE SpA - Environment and Sustainable Development Department, Milan (Italy)

2012-05-15

A flow injection analyser coupled with a gas diffusion membrane and a conductometric microdetector was adapted for the field analysis of natural concentrations of free dissolved CO{sub 2} and dissolved inorganic carbon in natural waters and used in a number of field campaigns for marine water monitoring. The dissolved gaseous CO{sub 2} presents naturally, or that generated by acidification of the sample, is separated by diffusion using a hydrophobic semipermeable gas porous membrane, and the permeating gas is incorporated into a stream of deionised water and measured by means of an electrical conductometric microdetector. In order to make the system suitable and easy to use for in-field measurements aboard oceanographic ships, the single components of the analyser were compacted into a robust and easy to use system. The calibration of the system is carried out by using standard solutions of potassium bicarbonate at two concentration ranges. Calibration and sample measurements are carried out inside a temperature-constant chamber at 25 C and in an inert atmosphere (N{sub 2}). The detection and quantification limits of the method, evaluated as 3 and 10 times the standard deviation of a series of measurements of the matrix solution were 2.9 and 9.6 {mu}mol/kg of CO{sub 2}, respectively. Data quality for dissolved inorganic carbon was checked with replicate measurements of a certified reference material (A. Dickson, Scripps Institution of Oceanography, University of California, San Diego), both accuracy and repeatability were -3.3% and 10%, respectively. Optimization, performance qualification of the system and its application in various natural water samples are reported and discussed. In the future, the calibration step will be operated automatically in order to improve the analytical performance and the applicability will be increased in the course of experimental surveys carried out both in marine and freshwater ecosystems. Considering the present stage of

Improving the relationship between soil characteristics and metal bioavailability by using reactive fractions of soil parameters in calcareous soils.

Science.gov (United States)

de Santiago-Martín, Ana; van Oort, Folkert; González, Concepción; Quintana, José R; Lafuente, Antonio L; Lamy, Isabelle

2015-01-01

The contribution of the nature instead of the total content of soil parameters relevant to metal bioavailability in lettuce was tested using a series of low-polluted Mediterranean agricultural calcareous soils offering natural gradients in the content and composition of carbonate, organic, and oxide fractions. Two datasets were compared by canonical ordination based on redundancy analysis: total concentrations (TC dataset) of main soil parameters (constituents, phases, or elements) involved in metal retention and bioavailability; and chemically defined reactive fractions of these parameters (RF dataset). The metal bioavailability patterns were satisfactorily explained only when the RF dataset was used, and the results showed that the proportion of crystalline Fe oxides, dissolved organic C, diethylene-triamine-pentaacetic acid (DTPA)-extractable Cu and Zn, and a labile organic pool accounted for 76% of the variance. In addition, 2 multipollution scenarios by metal spiking were tested that showed better relationships with the RF dataset than with the TC dataset (up to 17% more) and new reactive fractions involved. For Mediterranean calcareous soils, the use of reactive pools of soil parameters rather than their total contents improved the relationships between soil constituents and metal bioavailability. Such pool determinations should be systematically included in studies dealing with bioavailability or risk assessment. © 2014 SETAC.

In vivo induction of apoptosis in human lymphocytes by therapeutic fractionated total body irradiation

International Nuclear Information System (INIS)

Delic, J.; Magdelenat, H.; Barbaroux, C.; Chaillet, M.-P.; Dubray, B.; Fourquet, A.; Cosset, J.-M.; Gluckman, E.; Girinsky, T.

1995-01-01

Ionizing radiations have been reported as an in vitro apoptosis initiating stimulus in human lymphocytes. As the cytotoxicity of ionizing radiations and chemotherapeutic agents appears to be dependent on the efficacy of cell death induction, the manipulation of apoptosis initiation might be used as a means to suppress some pathological process. In the present study the in vivo induction of γ-ray mediated programmed cell death in humans is reported. The in vivo induction of apoptosis in peripheral blood lymphocytes (PBL) by ionizing radiations was investigated in 33 patients after each of two sessions (2 Gy and 4 Gy) of fractionated total body irradiation (FTBI) as part of their conditioning regimen before bone marrow transplantation. PBL committed to apoptosis were scored before irradiation (S1), 4 h (S2) and 24 h after 2 Gy (S3, 14-17 h after the second 2 Gy fraction). Nuclear morphology and chromatin-DNA were analysed by fluorescence microscopy immediately after blood sample withdrawal (I) and after 24 h in cell culture medium (II). (author)

Concentration and characterization of dissolved organic matter in the surface microlayer and subsurface water of the Bohai Sea, China

Science.gov (United States)

Chen, Yan; Yang, Gui-Peng; Wu, Guan-Wei; Gao, Xian-Chi; Xia, Qing-Yan

2013-01-01

A total of 19 sea-surface microlayer and corresponding subsurface samples collected from the Bohai Sea, China in April 2010 were analyzed for chlorophyll a, dissolved organic carbon (DOC) and its major compound classes including total dissolved carbohydrates (TDCHO, including monosaccharides, MCHO, and polysaccharides, PCHO) and total hydrolysable amino acids (THAA, including dissolved free, DFAA, and combined fraction, DCAA). The concentrations of DOC in the subsurface water ranged from 130.2 to 407.7 μM C, with an average of 225.9±75.4 μM C, while those in the surface microlayer varied between 140.1 and 330.9 μM C, with an average of 217.8±56.8 μM C. The concentrations of chlorophyll a, DOC, TDCHO and THAA in the microlayer were, respectively correlated with their subsurface water concentrations, implying that there was a strong exchange effect between the microlayer and subsurface water. The concentrations of DOC and TDCHO were negatively correlated with salinity, respectively, indicating that water mixing might play an important role in controlling the distribution of DOC and TDCHO in the water column. Major constituents of DCAA and DFAA present in the study area were glycine, alanine, glutamic acid, serine and histidine. Principal component analysis (PCA) was applied to examine the complex compositional differences that existed among the sampling sites. Our results showed that DFAA had higher mole percentages of glycine, valine and serine in the microlayer than in the subsurface water, while DCAA tended to have higher mole percentages of glutamic acid, aspartic acid, threonine, arginine, alanine, tyrosine, phenylalanine and leucine in the microlayer. The yields of TDCHO and THAA exhibited similar trends between the microlayer and subsurface water. Carbohydrate species displayed significant enrichment in the microlayer, whereas the DFAA and DCAA exhibited non-uniform enrichment in the microlayer.

Concentration, flux, and the analysis of trends of total and dissolved phosphorus, total nitrogen, and chloride in 18 tributaries to Lake Champlain, Vermont and New York, 1990–2011

Science.gov (United States)

Medalie, Laura

2013-01-01

Annual concentration, flux, and yield for total phosphorus, dissolved phosphorus, total nitrogen, and chloride for 18 tributaries to Lake Champlain were estimated for 1990 through 2011 using a weighted regression method based on time, tributary streamflows (discharges), and seasonal factors. The weighted regression method generated two series of daily estimates of flux and concentration during the period of record: one based on observed discharges and a second based on a flow-normalization procedure that removes random variation due to year-to-year climate-driven effects. The flownormalized estimate for a given date is similar to an average estimate of concentration or flux that would be made if all of the observed discharges for that date were equally likely to have occurred. The flux bias statistic showed that 68 of the 72 flux regression models were minimally biased. Temporal trends in the concentrations and fluxes were determined by calculating percent changes in flow-normalized annual fluxes for the full period of analysis (1990 through 2010) and for the decades 1990–2000 and 2000–2010. Basinwide, flow-normalized total phosphorus flux decreased by 42 metric tons per year (t/yr) between 1990 and 2010. This net result reflects a basinwide decrease in flux of 21 metric tons (t) between 1990 and 2000, followed by a decrease of 20 t between 2000 and 2010; both results were largely influenced by flux patterns in the large tributaries on the eastern side of the basin. A comparison of results for total phosphorus for the two separate decades of analysis found that more tributaries had decreasing concentrations and flux rates in the second decade than the first. An overall reduction in dissolved phosphorus flux of 0.7 t/yr was seen in the Lake Champlain Basin during the full period of analysis. That very small net change in flux reflects substantial reductions between 1990 and 2000 from eastern tributaries, especially in Otter Creek and the LaPlatte and Winooski

Storage and stability of biochar-derived carbon and total organic carbon in relation to minerals in an acid forest soil of the Spanish Atlantic area.

Science.gov (United States)

Fernández-Ugalde, Oihane; Gartzia-Bengoetxea, Nahia; Arostegi, Javier; Moragues, Lur; Arias-González, Ander

2017-06-01

Biochar can largely contribute to enhance organic carbon (OC) stocks in soil and improve soil quality in forest and agricultural lands. Its contribution depends on its recalcitrance, but also on its interactions with minerals and other organic compounds in soil. Thus, it is important to study the link between minerals, natural organic matter and biochar in soil. In this study, we investigated the incorporation of biochar-derived carbon (biochar-C) into various particle-size fractions with contrasting mineralogy and the effect of biochar on the storage of total OC in the particle-size fractions in an acid loamy soil under Pinus radiata (C3 type) in the Spanish Atlantic area. We compared plots amended with biochar produced from Miscanthus sp. (C4 type) with control plots (not amended). We separated sand-, silt-, and clay-size fractions in samples collected from 0 to 20-cm depth. In each fraction, we analyzed clay minerals, metallic oxides and oxy-hydroxides, total OC and biochar-C. The results showed that 51% of the biochar-C was in fractions fractions (0.2-2μm, 0.05-0.2μm, fractions, as it occurred with the vermiculitic phases and metallic oxides and oxy-hydroxides. Biochar also affected to the distribution of total OC among particle-size fractions. Total OC concentration was greater in fractions 2-20μm, 0.2-2μm, 0.05-0.2μm in biochar-amended plots than in control plots. This may be explained by the adsorption of dissolved OC from fraction organic matter already occurred in the first year. Copyright © 2017 Elsevier B.V. All rights reserved.

Production of Dissolved Organic Matter During Doliolid Feeding

Science.gov (United States)

Castellane, N. J.; Paffenhofer, G. A.; Stubbins, A.

2016-02-01

The biological carbon pump (BCP) draws carbon dioxide out of the atmosphere and buries it at the seafloor. The efficiency of the BCP is determined in part by the sinking rates of particulate organic carbon (POC) from ocean surface waters. Zooplankton can package POC into fecal pellets with higher sinking rates than their food source (e.g. phytoplankton), increasing the efficiency of the BCP. However, dissolved organic carbon (DOC) is also produced as zooplankton ingest and egest food, reducing the efficiency of BCP. The pelagic tunicate Dolioletta gegenbauri (doliolid) is a gelatinous zooplankton found at high concentrations in shelf waters, including our study site: the South Atlantic Bight. Doliolids are efficient grazers capable of stripping large quantities of phytoplankton from the water column. To determine the balance between pellet formation and DOC production during feeding, doliolids (6-7 mm gonozooids) were placed in natural seawater amended with a live phytoplankton food source and incubated on a plankton wheel. Dissolved organic matter (DOM) released directly to the water as well as the water soluble fraction of pellet organic matter were quantified and optically characterized. Colored dissolved organic matter (CDOM) absorbance and fluorescence spectra revealed that doliolid feeding produces DOM with optical properties that are commonly indicative of newly produced, highly biolabile DOM of microbial origin. Based upon these optical characteristics, doliolid-produced DOM is expected to be highly bio-labile in the environment and therefore rapidly degraded by surface ocean microbes shunting phytoplankton-derived organic carbon out of the BCP and back to dissolved inorganic carbon.

Second Study of Hyper-Fractionated Radiotherapy

Directory of Open Access Journals (Sweden)

R. Jacob

1999-01-01

Full Text Available Purpose and Method. Hyper-fractionated radiotherapy for treatment of soft tissue sarcomas is designed to deliver a higher total dose of radiation without an increase in late normal tissue damage. In a previous study at the Royal Marsden Hospital, a total dose of 75 Gy using twice daily 1.25 Gy fractions resulted in a higher incidence of late damage than conventional radiotherapy using 2 Gy daily fractions treating to a total of 60 Gy. The current trial therefore used a lower dose per fraction of 1.2 Gy and lower total dose of 72 Gy, with 60 fractions given over a period of 6 weeks.

THE CHANGE OF TOTAL PROTEIN FRACTION OF MUSCLE TISSUE OF PORK WITH BIO- AND PHYSICO-CHEMICAL SPECIFIC IN THE PROCESS OF COOKING AT DIFFERENT TEMPERATURES

Directory of Open Access Journals (Sweden)

O. Shalimova

2012-03-01

Full Text Available The character of changes in total protein fraction of muscle tissue of pork with PSE defects in the process of cooking at temperatures ranging from 40 to 72 g.C in steps of 2 g.C is investigated. Our studies have revealed differences in the change of state the total fraction of muscle proteins with defects PSE pork during cooking.

The relationship of metals, bifenthrin, physical habitat metrics, grain size, total organic carbon, dissolved oxygen and conductivity to Hyalella sp. abundance in urban California streams.

Science.gov (United States)

Hall, Lenwood W; Anderson, Ronald D

2013-01-01

The objectives of this study were to determine the relationship between Hyalella sp. abundance in four urban California streams and the following parameters: (1) 8 bulk metals (As, Cd, Cr, Cu, Pb, Hg, Ni, and Zn) and their associated sediment Threshold Effect Levels (TELs); (2) bifenthrin sediment concentrations; (3) 10 habitat metrics and total score; (4) grain size (% sand, silt and clay); (5) Total Organic Carbon (TOC); (6) dissolved oxygen; and (7) conductivity. California stream data used for this study were collected from Kirker Creek (2006 and 2007), Pleasant Grove Creek (2006, 2007 and 2008), Salinas streams (2009 and 2010) and Arcade Creek (2009 and 2010). Hyalella abundance in the four California streams generally declined when metals concentrations were elevated beyond the TELs. There was also a statistically significant negative relationship between Hyalella abundance and % silt for these 4 California streams as Hyalella were generally not present in silt areas. No statistically significant relationships were reported between Hyalella abundance and metals concentrations, bifenthrin concentrations, habitat metrics, % sand, % clay, TOC, dissolved oxygen and conductivity. The results from this study highlight the complexity of assessing which factors are responsible for determining the abundance of amphipods, such as Hyalella sp., in the natural environment.

Total variation regularization for a backward time-fractional diffusion problem

International Nuclear Information System (INIS)

Wang, Liyan; Liu, Jijun

2013-01-01

Consider a two-dimensional backward problem for a time-fractional diffusion process, which can be considered as image de-blurring where the blurring process is assumed to be slow diffusion. In order to avoid the over-smoothing effect for object image with edges and to construct a fast reconstruction scheme, the total variation regularizing term and the data residual error in the frequency domain are coupled to construct the cost functional. The well posedness of this optimization problem is studied. The minimizer is sought approximately using the iteration process for a series of optimization problems with Bregman distance as a penalty term. This iteration reconstruction scheme is essentially a new regularizing scheme with coupling parameter in the cost functional and the iteration stopping times as two regularizing parameters. We give the choice strategy for the regularizing parameters in terms of the noise level of measurement data, which yields the optimal error estimate on the iterative solution. The series optimization problems are solved by alternative iteration with explicit exact solution and therefore the amount of computation is much weakened. Numerical implementations are given to support our theoretical analysis on the convergence rate and to show the significant reconstruction improvements. (paper)

Arsenic speciation in the dispersible colloidal fraction of soils from a mine-impacted creek

International Nuclear Information System (INIS)

Serrano, Susana; Gomez-Gonzalez, Miguel Angel; O’Day, Peggy A.; Laborda, Francisco; Bolea, Eduardo; Garrido, Fernando

2015-01-01

Highlights: • Nanoparticle scorodite may dissolve from mine wastes and release As down-gradient. • Large fractions of total As in soils may be associated with dispersible colloids. • Up to one third of total As in soils was associated with the colloid fraction. • AsFlFFF-ICP-MS and XAS provides information on the partitioning of contaminants in colloids. - Abstract: Arsenic and iron speciation in the dispersible colloid fraction (DCF; 10–1000 nm) from an As-rich mine waste pile, sediments of a streambed that collects runoff from waste pile, the streambed subsoil, and the sediments of a downstream pond were investigated by combining asymmetrical-flow field-flow fractionation (AsFlFFF)/inductively-coupled plasma–mass spectrometry (ICP–MS), transmission electron microscopy (TEM) and X-ray absorption (XAS) spectroscopy. Calcium, Fe and As (Fe/As molar ratio ∼ 1) were the main components of the DCF from waste pile. TEM/EDS and As and Fe XAS analysis revealed the presence of nanoparticle scorodite in this same DCF, as well as Fe nanoparticles in all samples downstream of the waste pile. Arsenic and Fe XAS showed As(V) adsorbed onto nanoparticulate ferrihydrite in the DCF of downstream samples. Micro-X-ray fluorescence indicated a strong correlation between Fe and As in phyllosilicate/Fe 3+ (oxi) hydroxide aggregates from the sediment pond. Fractionation analysis showed the mean particle size of the DCF from the streambed sample to be smaller than that of the streambed subsoil and sediment ponds samples. These results show that an important and variable fraction of As may be bound to dispersible colloids that can be released from contaminated soils and transported downstream in natural systems

Arsenic speciation in the dispersible colloidal fraction of soils from a mine-impacted creek

Energy Technology Data Exchange (ETDEWEB)

Serrano, Susana [Institute of Agrochemistry and Food Technology, CSIC, Agustín Escardino 7, 46980 Paterna, Valencia (Spain); Gomez-Gonzalez, Miguel Angel [National Museum of Natural Sciences, CSIC, José Gutiérrez Abascal 2, 28006 Madrid (Spain); O’Day, Peggy A. [School of Natural Sciences,University of California, Merced, CA 95343 (United States); Laborda, Francisco; Bolea, Eduardo [Group of Analytical Spectroscopy and Sensors (GEAS), Institute of Environmental Sciences (IUCA), University of Zaragoza, Pedro Cerbuna 12, 50009 Zaragoza (Spain); Garrido, Fernando, E-mail: fernando.garrido@mncn.csic.es [National Museum of Natural Sciences, CSIC, José Gutiérrez Abascal 2, 28006 Madrid (Spain)

2015-04-09

Highlights: • Nanoparticle scorodite may dissolve from mine wastes and release As down-gradient. • Large fractions of total As in soils may be associated with dispersible colloids. • Up to one third of total As in soils was associated with the colloid fraction. • AsFlFFF-ICP-MS and XAS provides information on the partitioning of contaminants in colloids. - Abstract: Arsenic and iron speciation in the dispersible colloid fraction (DCF; 10–1000 nm) from an As-rich mine waste pile, sediments of a streambed that collects runoff from waste pile, the streambed subsoil, and the sediments of a downstream pond were investigated by combining asymmetrical-flow field-flow fractionation (AsFlFFF)/inductively-coupled plasma–mass spectrometry (ICP–MS), transmission electron microscopy (TEM) and X-ray absorption (XAS) spectroscopy. Calcium, Fe and As (Fe/As molar ratio ∼ 1) were the main components of the DCF from waste pile. TEM/EDS and As and Fe XAS analysis revealed the presence of nanoparticle scorodite in this same DCF, as well as Fe nanoparticles in all samples downstream of the waste pile. Arsenic and Fe XAS showed As(V) adsorbed onto nanoparticulate ferrihydrite in the DCF of downstream samples. Micro-X-ray fluorescence indicated a strong correlation between Fe and As in phyllosilicate/Fe{sup 3+} (oxi) hydroxide aggregates from the sediment pond. Fractionation analysis showed the mean particle size of the DCF from the streambed sample to be smaller than that of the streambed subsoil and sediment ponds samples. These results show that an important and variable fraction of As may be bound to dispersible colloids that can be released from contaminated soils and transported downstream in natural systems.

Salinity: Electrical conductivity and total dissolved solids

Science.gov (United States)

The measurement of soil salinity is a quantification of the total salts present in the liquid portion of the soil. Soil salinity is important in agriculture because salinity reduces crop yields by reducing the osmotic potential making it more difficult for the plant to extract water, by causing spe...

Concentration and fractionation of hydrophobic organic acid constituents from natural waters by liquid chromatography

Science.gov (United States)

Thurman, E.M.; Malcolm, R.L.

1979-01-01

A scheme is presented which used adsorption chromatography with pH gradient elution and size-exclusion chromatography to concentrate and separate hydrophobic organic acids from water. A review of chromatographic processes involved in the flow scheme is also presented. Organic analytes which appear in each aqueous fraction are quantified by dissolved organic carbon analysis. Hydrophobic organic acids in a water sample are concentrated on a porous acrylic resin. These acids usually constitute approximately 30-50 percent of the dissolved organic carbon in an unpolluted water sample and are eluted with an aqueous eluent (dilute base). The concentrate is then passed through a column of polyacryloylmorpholine gel, which separates the acids into high- and low-molecular-weight fractions. The high- and low-molecular-weight eluates are reconcentrated by adsorption chromatography, then are eluted with a pH gradient into strong acids (predominately carboxylic acids) and weak acids (predominately phenolic compounds). For standard compounds and samples of unpolluted waters, the scheme fractionates humic substances into strong and weak acid fractions that are separated from the low molecular weight acids. A new method utilizing conductivity is also presented to estimate the acidic components in the methanol fraction.

Effect of fractionated versus unfractionated total body irradiation on the growth of the BN acute myelocytic leukemia

International Nuclear Information System (INIS)

Hagenbeek, A.; Martens, A.C.M.

1981-01-01

The efficacy of various total body irradiation (TBI) regimens prior to bone marrow transplantation was evaluated in a rat model for acute myelocytic leukemia (Dq = 85.1 cGy gamma ; N = 3.7). Using high dose rate gamma-irradiation (115 cGy/min), fractionated TBI with large total daily doses (400 to 600 cGy), either given as acute doses or as split doses at 8 hr intervals, was most effective. Split doses (2 fractions per day) offered no additional advantage. At the most, a 4 log leukemic cell kill was induced. No lethal toxicity was observed. Nine-hundred cGy flash TBI had a similar anti-tumor effect, but with this regimen almost half of the rats died from radiation-induced toxicity (lungs and gastro-intestinal tract). The results are explained in terms of differences between normal and leukemic cells as regards (a) repair of sublethal damage; and (b) repopulation. Low dose rate continuous gamma-irradiation (0.26 cGy/min) with total doses ranging from 900 to 2000 cGy was also quite effective. Maximally a 4 log cell kill was obtained. With 2000 cGy, 50% of the rats died from the gastro-intestinal tract-syndrome. In addition to the major role played by chemotherapy, TBI is mainly of importance in sterilizing the various sanctuaries in the body which contain leukemic cells anatomically resistant to most cytostatic agents

On-line technique for preparingand measuring stable carbon isotopeof total dissolved inorganic carbonin water samples ( d13CTDIC

Directory of Open Access Journals (Sweden)

S. Inguaggiato

2005-06-01

Full Text Available A fast and completely automated procedure is proposed for the preparation and determination of d13C of total inorganic carbon dissolved in water ( d13CTDIC. This method is based on the acidification of water samples transforming the whole dissolved inorganic carbon species into CO2. Water samples are directly injected by syringe into 5.9 ml vials with screw caps which have a pierciable rubber septum. An Analytical Precision «Carbonate Prep System» was used both to flush pure helium into the vials and to automatically dispense a fixed amount of H3PO4. Full-equilibrium conditions between produced CO2 and water are reached at a temperature of 70°C (± 0.1°C in less than 24 h. Carbon isotope ratios (13C/ 12C were measured on an AP 2003 continuous flow mass spectrometer, connected on-line with the injection system. The precision and reproducibility of the proposed method was tested both on aqueous standard solutions prepared using Na2CO3 with d13C=-10.78 per mil versus PDB (1 s= 0.08, n = 11, and at five different concentrations (2, 3, 4, 5 and 20 mmol/l and on more than thirty natural samples. Mean d13CTDIC on standard solution samples is ?10.89 < per mil versus PDB (1 s= 0.18, n = 50, thus revealing both a good analytical precision and reproducibility. A comparison between average d13CTDIC values on a quadruplicate set of natural samples and those obtained following the chemical and physical stripping method highlights a good agreement between the two analytical methods.

Assessment of pesticide availability in soil fractions after the incorporation of winery-distillery vermicomposts

Energy Technology Data Exchange (ETDEWEB)

Fernandez-Bayo, J.D. [Department of Environmental Protection, Estacion Experimental del Zaidin (CSIC), C/Profesor Albareda 1, 18008 Granada (Spain)], E-mail: jesus.bayo@eez.csic.es; Romero, E. [Department of Environmental Protection, Estacion Experimental del Zaidin (CSIC), C/Profesor Albareda 1, 18008 Granada (Spain); Schnitzler, F.; Burauel, P. [Agrosphere Institute, ICG 4, Forschungszentrum Juelich, Juelich (Germany)

2008-07-15

The influence of two vermicomposts from winery and distillery wastes on the distribution of diuron in agricultural soil was studied. Physical soil fractionations at 0, 9, 27, 49 and 77 days, allowed the quantification of pesticide residues in different particle-size fractions, coarse waste (WF), sand-sized (SF), silt-sized (SiF), clay-sized (CF) and dissolved organic matter-sized fraction (DOM). The SiF made a greater contribution to the formation of non-extractable residues in unamended soil, but when vermicomposts were added, new sorption sites in WF appeared, being higher for the more humified vermicompost V2. The dissolved organic carbon (DOC) increased with the addition of vermicompost, but the concentration of the desorbed {sup 14}C-radiochemical did not increase. Non-significant increment was observed with time for the non-extractable fraction with amendments. Diuron was transformed in all samples, although less than 0.5% was mineralized. The main effect caused by vermicomposts was a reduction in the availability of diuron in soil. - Winery vermicomposts as organic amendments to reduce pesticide pollution.

Assessment of pesticide availability in soil fractions after the incorporation of winery-distillery vermicomposts

International Nuclear Information System (INIS)

Fernandez-Bayo, J.D.; Romero, E.; Schnitzler, F.; Burauel, P.

2008-01-01

The influence of two vermicomposts from winery and distillery wastes on the distribution of diuron in agricultural soil was studied. Physical soil fractionations at 0, 9, 27, 49 and 77 days, allowed the quantification of pesticide residues in different particle-size fractions, coarse waste (WF), sand-sized (SF), silt-sized (SiF), clay-sized (CF) and dissolved organic matter-sized fraction (DOM). The SiF made a greater contribution to the formation of non-extractable residues in unamended soil, but when vermicomposts were added, new sorption sites in WF appeared, being higher for the more humified vermicompost V2. The dissolved organic carbon (DOC) increased with the addition of vermicompost, but the concentration of the desorbed 14 C-radiochemical did not increase. Non-significant increment was observed with time for the non-extractable fraction with amendments. Diuron was transformed in all samples, although less than 0.5% was mineralized. The main effect caused by vermicomposts was a reduction in the availability of diuron in soil. - Winery vermicomposts as organic amendments to reduce pesticide pollution

Methods And Apparatus For Acoustic Fiber Fractionation

Science.gov (United States)

Brodeur, Pierre

1999-11-09

Methods and apparatus for acoustic fiber fractionation using a plane ultrasonic wave field interacting with water suspended fibers circulating in a channel flow using acoustic radiation forces to separate fibers into two or more fractions based on fiber radius, with applications of the separation concept in the pulp and paper industry. The continuous process relies on the use of a wall-mounted, rectangular cross-section piezoelectric ceramic transducer to selectively deflect flowing fibers as they penetrate the ultrasonic field. The described embodiment uses a transducer frequency of approximately 150 kHz. Depending upon the amount of dissolved gas in water, separation is obtained using a standing or a traveling wave field.

Effects of Total Dissolved Gas on Chum Salmon Fry Incubating in the Lower Columbia River

Energy Technology Data Exchange (ETDEWEB)

Arntzen, Evan V.; Hand, Kristine D.; Geist, David R.; Murray, Katherine J.; Panther, Jenny; Cullinan, Valerie I.; Dawley, Earl M.; Elston, Ralph A.

2008-01-30

This report describes research conducted by Pacific Northwest National Laboratory in FY 2007 for the U.S. Army Corps of Engineers, Portland District, to characterize the effects of total dissolved gas (TDG) on the incubating fry of chum salmon (Onchorhynchus keta) in the lower Columbia River. The tasks conducted and results obtained in pursuit of three objectives are summarized: * to conduct a field monitoring program at the Ives Island and Multnomah Falls study sites, collecting empirical data on TDG to obtain a more thorough understanding of TDG levels during different river stage scenarios (i.e., high-water year versus low-water year) * to conduct laboratory toxicity tests on hatchery chum salmon fry at gas levels likely to occur downstream from Bonneville Dam * to sample chum salmon sac fry during Bonneville Dam spill operations to determine if there is a physiological response to TDG levels. Chapter 1 discusses the field monitoring, Chapter 2 reports the findings of the laboratory toxicity tests, and Chapter 3 describes the field-sampling task. Each chapter contains an objective-specific introduction, description of the study site and methods, results of research, and discussion of findings. Literature cited throughout this report is listed in Chapter 4. Additional details on the study methdology and results are provided in Appendixes A through D.

Octanol-solubility of dissolved and particulate trace metals in contaminated rivers: implications for metal reactivity and availability

Energy Technology Data Exchange (ETDEWEB)

Turner, Andrew [School of Earth, Ocean and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA (United Kingdom)]. E-mail: aturner@plymouth.ac.uk; Mawji, Edward [School of Earth, Ocean and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA (United Kingdom)

2005-05-01

The lipid-like, amphiphilic solvent, n-octanol, has been used to determine a hydrophobic fraction of dissolved and particulate trace metals (Al, Cd, Co, Cu, Mn, Ni, Pb, Zn) in contaminated rivers. In a sample from the River Clyde, southwest Scotland, octanol-solubility was detected for all dissolved metals except Co, with conditional octanol-water partition coefficients, D{sub ow}, ranging from about 0.2 (Al and Cu) to 1.25 (Pb). In a sample taken from the River Mersey, northwest England, octanol-solubility was detected for dissolved Al and Pb, but only after sample aliquots had been spiked with individual ionic metal standards and equilibrated. Spiking of the River Clyde sample revealed competition among different metals for hydrophobic ligands. Metal displacement from hydrophobic complexes was generally most significant following the addition of ionic Al or Pb, although the addition of either of these metals had little effect on the octanol-solubility of the other. In both river water samples hydrophobic metals were detected on the suspended particles retained by filtration following their extraction in n-octanol. In general, particulate Cu and Zn (up to 40%) were most available, and Al, Co and Pb most resistant (<1%) to octanol extraction. Distribution coefficients defining the concentration ratio of octanol-soluble particle-bound metal to octanol-soluble dissolved metal were in the range 10{sup 3.3}-10{sup 5.3} ml g{sup -1}. The presence of hydrophobic dissolved and particulate metal species has implications for our understanding of the biogeochemical behaviour of metals in aquatic environments. Specifically, such species are predicted to exhibit characteristics of non-polar organic contaminants, including the potential to penetrate the lipid bilayer. Current strategies for assessing the bioavailability and toxicity of dissolved and particulate trace metals in natural waters may, therefore, require revision. - New approaches are presented for fractionating

Global trends in the fluorescence characteristics and distribution of marine dissolved organic matter

DEFF Research Database (Denmark)

Jørgensen, Linda; Stedmon, Colin; Kragh, Theis

2011-01-01

. These observations imply a link to dark ocean microbial remineralization and indicate that the major source of humic-like compounds is microbial turnover of organic matter. The results of the present study show that the distribution of the humic-like DOM fractions is a balance between supply from continental run off......A fraction of dissolved organic matter (DOM) is able to fluoresce. This ability has been used in the present study to investigate the characteristics and distribution of different DOM fractions. A unique global dataset revealed seven different fluorescent fractions of DOM: two humic-like, four...... in the surface layer indicate the quantitative importance of photochemical degradation as a sink of the humic-like compounds. In the dark ocean (below 200 m), significant linear relationships between humic-like DOM fluorescence and microbial activity (apparent oxygen utilization, NO3- and PO43-) were found...

Partitioning and distribution of dissolved copper, cadmium and organic matter in Mediterranean marine coastal areas: The case of a mucilage event

Science.gov (United States)

Scoullos, Michael; Plavšić, Marta; Karavoltsos, Sotiris; Sakellari, Aikaterini

2006-04-01

Dissolved copper and cadmium partitioning and their interaction with organic matter were investigated in shallow coastal areas of the Aegean Sea (Eastern Mediterranean). The percentage of DGT-labile copper as for total dissolved copper ranged from 13 to 34% during summer and from 23 to 36% during winter, whereas the corresponding percentage for DGT-labile cadmium was higher in summer (38-68%), in comparison to winter (29-44%). The CCu was found to be 100-260 nM during summer while in winter the range was 42-430 nM. The corresponding CCd reached 27 and 45 nM, respectively. The mean TEP value in summer was high (208 μg/L xanthan equiv.), while in winter it reached 441 μg/L xanthan equiv., which indicates significant phytoplankton activity in winter, a feature occasionally observed in the stratified study areas after the breaking down of the thermocline/pycnocline, followed by consequent nutrient enrichment of the surface layers by nutrients accumulated in the sea bottom. A significant fraction of dissolved organic carbon (DOC) exhibited surface active properties and was determined as surface active substances (SAS) in mg/L eq. of nonionic surfactant Triton-X-100. Carbohydrates were also determined and they represented up to 33% of the DOC.

Influence of radiation field and fractionation schedule of total lymphoid irradiation (TLI) on the induction of suppressor cells and stable chimerism after bone marrow transplantation in mice

International Nuclear Information System (INIS)

Waer, M.; Ang, K.K.; van der Schueren, E.; Vandeputte, M.

1984-01-01

When BALB/c mice received 17 daily fractions of 2 Gy each of total lymphoid irradiation (TLI, total dose 34 Gy) and 30 x 10 6 C 57 B1 bone marrow cells (BM) on the day after the last fraction, stable bone marrow chimerism without signs of graft-vs-host disease (GVHD) was obtained in 84% of the animals. On the contrary, in BALB/c mice receiving only seven fractions of TLI (total dose 14 Gy), all bone marrow grafts were rejected. When the last two fractions of a 14-Gy TLI course were given without shielding the extra lymphatic tissues (combined total lymphoid + total body irradiation, TLBI), chimerism could be induced in 53% of the animals. When this 14-Gy TLBI schedule was used, it was even possible to administer four fractions per day (multiple fractions per day schedule, MFD), thus reducing the overall treatment time to 2 consecutive days. After this concentrated form of TLBI, chimerism was detected in 35% of the animals. As in the 34-Gy TLI schedule, graft-vs-host reaction could not be prevented in the 14-Gy TLBI schedule when spleen lymphocytes (10 x 10 6 ) were added to the BM inocolum. Leucopenia or suppression of the phytohaemagglutinin (PHA)-induced blastogenesis could not predict which schedule would result in a successful allogeneic bone marrow take. Suppressor cells of the mixed lymphocyte reaction, on the other hand, were only found in the spleen of BALB/c mice treated with the TLI or TLBI schedules, which also resulted in stable bone marrow chimerism

Dissolved organic carbon fractionation accelerates glacier-melting: A case study in the northern Tibetan Plateau.

Science.gov (United States)

Hu, Zhaofu; Kang, Shichang; Yan, Fangping; Zhang, Yulan; Li, Yang; Chen, Pengfei; Qin, Xiang; Wang, Kun; Gao, Shaopeng; Li, Chaoliu

2018-06-15

In glacierized regions, melting process has a significant effect on concentrations and light absorption characteristics of dissolved organic carbon (DOC), potentially resulting in variations of its radiative forcing, which is not yet relevant research at glacier region of the Tibetan Plateau (TP). In this study, DOC fractionation and its radiative forcing change during the melting process were investigated at Laohugou glacier No. 12 (LHG glacier) in western Qilian Mts., northern TP. DOC concentrations in fresh snow, snowpit and surface ice samples were 0.38 ± 0.06, 0.22 ± 0.11 and 0.60 ± 0.21 mg L -1 , respectively. Their mass absorption cross-section at 365 nm (MAC 365 ) were 0.65 ± 0.16, 4.71 ± 3.68 and 1.44 ± 0.52 m 2  g -1 , respectively. The MAC 365 values of snowpit samples showed a significant negative correlation with DOC concentrations, indicating DOC with high MAC 365 values were likely to be kept in snow during the melting process. Topsoil samples of LHG glacierized region likely contributed a lot to snowpit DOC with high MAC 365 values due to their similar absorption spectra. Spatially, the DOC concentration of surface ice samples increased from terminus to the upper part of the glacier. Correspondingly, the MAC 365 value showed decreased trend. In the freezing experiment on surface ice and topsoil samples, small part of DOC with high MAC 365 value was also likely to enter first frozen solid phase. In addition, the radiative forcing caused by snowpit and surface ice DOC increased around 7.64 ± 2.93 and 4.95 ± 1.19 times relative to fresh snow DOC, indicating the snow/ice melting caused by increased light-absorbing DOC needs to be considered in the future research. Copyright © 2018 Elsevier B.V. All rights reserved.

Differential chemical fractionation of dissolved organic matter during sorption by Fe mineral phases in a tropical soil from the Luquillo Critical Zone Observatory

Science.gov (United States)

Plante, A. F.; Coward, E.; Ohno, T.; Thompson, A.

2017-12-01

Fe-bearing mineral phases contribute substantially to adsorption and stabilization of soil organic matter (SOM), due largely to their high specific surface area (SSA) and reactivity. While the importance of adsorption onto mineral surfaces has been well-elucidated, selectivity of various mineral and organic phases remains poorly understood. The goals of this work were to: 1) quantify the contributions of Fe-minerals of varying crystallinity to dissolved organic matter (DOM) sorption, and 2) characterize the molecular fractionation of DOM induced by reactions at the mineral interface, using a highly-weathered Oxisol from the Luquillo Critical Zone Observatory (LCZO). Three selective dissolution experiments targeting Fe-mineral phases were followed by specific surface area (SSA) analysis of the residues and characterization of extracted DOM by high resolution mass spectrometry (FT-ICR-MS). Fe-depleted extraction residue samples, untreated control soil samples, and Fe-enriched ferrihydrite-coated soil samples were then subjected to a batch sorption experiment with litter-derived DOM. Results of selective dissolution experiments indicated that a substantial proportion of soil SSA was derived from extracted Fe-bearing phases, and FT-ICR-MS analysis of extracted DOM revealed distinct chemical signatures. Sorbed C concentrations were well correlated with Fe contents induced by treatments, and thus SSA. Molecular characterization of the DOM post-sorption indicated that poorly crystalline Fe phases preferentially adsorbed highly unsaturated aromatic compounds, and higher-crystallinity Fe phases were associated with more aliphatic compounds. These findings suggests that molecular fractionation via organomineral complexation may act as a physicochemical filter of DOM released to the critical zone.

Distribution of dissolved labile and particulate iron and copper in Terra Nova Bay polynya (Ross Sea, Antarctica) surface waters in relation to nutrients and phytoplankton growth

Science.gov (United States)

Rivaro, Paola; Ianni, Carmela; Massolo, Serena; Abelmoschi, M. Luisa; De Vittor, Cinzia; Frache, Roberto

2011-05-01

The distribution of the dissolved labile and of the particulate Fe and Cu together with dissolved oxygen, nutrients, chlorophyll a and total particulate matter was investigated in the surface waters of Terra Nova Bay polynya in mid-January 2003. The measurements were conducted within the framework of the Italian Climatic Long-term Interactions of the Mass balance in Antarctica (CLIMA) Project activities. The labile dissolved fraction was operationally defined by employing the chelating resin Chelex-100, which retains free and loosely bound trace metal species. The dissolved labile Fe ranges from below the detection limit (0.15 nM) to 3.71 nM, while the dissolved labile Cu from below the detection limit (0.10 nM) to 0.90 nM. The lowest concentrations for both metals were observed at 20 m depth (the shallowest depth for which metals were measured). The concentration of the particulate Fe was about 5 times higher than the dissolved Fe concentration, ranging from 0.56 to 24.83 nM with an average of 6.45 nM. The concentration of the particulate Cu ranged from 0.01 to 0.71 nM with an average of 0.17 nM. The values are in agreement with the previous data collected in the same area. We evaluated the role of the Fe and Cu as biolimiting metals. The N:dissolved labile Fe ratios (18,900-130,666) would or would not allow a complete nitrate removal, on the basis of the N:Fe requirement ratios that we calculated considering the N:P and the C:P ratios estimated for diatoms. This finding partially agrees with the Si:N ratio that we found (2.29). Moreover we considered a possible influence of the dissolved labile Cu on the Fe uptake process.

Calcium Isotope Geochemistry: Research Horizons and Nanoscale Fractionation Processes

Science.gov (United States)

Watkins, J. M.; Depaolo, D. J.; Richter, F. M.; Fantle, M. S.; Simon, J. I.; Ryerson, F. J.; Ewing, S. A.; Turchyn, A. V.; Yang, W.; Owens, T. L.

2008-12-01

Interest in studies of calcium isotope variations in nature continues to increase. Investigations span human biology, plants and soils, oceanography and paleoclimate, early solar system processes, aqueous geochemistry, and silicate liquid structure. Variations in the 44Ca/40Ca ratio are generally small, about 5 ‰, but gradual small improvements in analytical capability now yield 0.05 to 0.1 ‰ resolution. The field is still plagued by a lack of universal standards for isotope ratios and data representation, but these are secondary issues. Traditional isotopic systems have been based in equilibrium thermodynamics, which can explain the magnitude and sign of observed mass-dependent fractionation behavior. For Ca isotopes this is not the case. There is still no reliable way to estimate the equilibrium free energy associated with isotopic exchange between most phases of interest. Experiments are difficult to interpret because it is almost impossible to precipitate minerals from aqueous solution at equilibrium at low temperature. Some studies suggest that, for example, there is no equilibrium isotopic fractionation between calcite and dissolved aqueous Ca. There is good evidence that most Ca isotopic fractionation is caused by kinetic effects. The details of the controlling processes are still missing, and without this mechanistic understanding it is difficult to fully understand the implications of natural isotopic variations. Recent work on dissolved Ca, calcite, and sulfates in both laboratory and natural settings is shedding light on where the fractionation may arise. There is emerging evidence for mass dependent fractionation associated with aqueous diffusion, but probably the primary source of the effects is in the details of precipitation of minerals from solution. This makes the fractionation potentially dependent on a number of factors, including solution composition and mineral growth rate. The next challenge is to develop appropriate experimental tests and

Octanol-solubility of dissolved and particulate trace metals in contaminated rivers: implications for metal reactivity and availability

International Nuclear Information System (INIS)

Turner, Andrew; Mawji, Edward

2005-01-01

The lipid-like, amphiphilic solvent, n-octanol, has been used to determine a hydrophobic fraction of dissolved and particulate trace metals (Al, Cd, Co, Cu, Mn, Ni, Pb, Zn) in contaminated rivers. In a sample from the River Clyde, southwest Scotland, octanol-solubility was detected for all dissolved metals except Co, with conditional octanol-water partition coefficients, D ow , ranging from about 0.2 (Al and Cu) to 1.25 (Pb). In a sample taken from the River Mersey, northwest England, octanol-solubility was detected for dissolved Al and Pb, but only after sample aliquots had been spiked with individual ionic metal standards and equilibrated. Spiking of the River Clyde sample revealed competition among different metals for hydrophobic ligands. Metal displacement from hydrophobic complexes was generally most significant following the addition of ionic Al or Pb, although the addition of either of these metals had little effect on the octanol-solubility of the other. In both river water samples hydrophobic metals were detected on the suspended particles retained by filtration following their extraction in n-octanol. In general, particulate Cu and Zn (up to 40%) were most available, and Al, Co and Pb most resistant ( 3.3 -10 5.3 ml g -1 . The presence of hydrophobic dissolved and particulate metal species has implications for our understanding of the biogeochemical behaviour of metals in aquatic environments. Specifically, such species are predicted to exhibit characteristics of non-polar organic contaminants, including the potential to penetrate the lipid bilayer. Current strategies for assessing the bioavailability and toxicity of dissolved and particulate trace metals in natural waters may, therefore, require revision. - New approaches are presented for fractionating trace metals in natural waters

Stable isotope fractionation at a glacial hydrothermal field: implications for biogeochemistry and biosignatures on Mars

Science.gov (United States)

Cousins, C.; Bowden, R.; Fogel, M.; Cockell, C.; Crawford, I.; Gunn, M.; Karlsson, M. T.; Thorsteinsson, T.

2012-12-01

Hydrothermal environments that arise through the interaction between volcanogenic heat and glacial ice are ideal sites for understanding microbial biogeochemical processes on Earth, and also potentially on Mars where similar volcano-cryosphere interactions are thought to have occurred in the past. The Kverkfjöll subglacial basaltic volcano in central Iceland is geographically isolated, with little influence from flora, fauna, and human activity. Major environmental inputs include geothermal heat, meltwater from ice and snow, and outgassing of CO2, H2S, and SO2. Large physiochemical gradients exist, from steaming fumaroles and boiling hydrothermal pools, to frozen geothermal ground and glacial ice. Stable isotope measurements of total organic carbon, total sulphur, and total nitrogen were coupled with metagenomic analysis of the residing microbial communities, with the aim to identify biogeochemical relationships and processes operating within the Kverkfjöll geothermal environment, and also to identify any isotopic biosignatures that could be preserved within geothermal sediments. This study focused on a variety of samples taken along a hot spring stream that fed into a large ice-confined geothermal lake. Samples analysed range from unconsolidated hot spring sediments, well-developed microbial mats, and dissolved sulphate from hot spring fluids. From the anoxic spring source, the stream water increases in dissolved oxygen, decreases in temperature, yet maintains a pH of ~4. The spring environment is dominated by dissolved sulphate (~2.3 mM), with lower levels of nitrate (~50 μM), phosphorus (~5μM), and ammonium (~1.5 μM). Stable S isotope analysis reveals a fractionation of ~3.2 ‰ between sediment sulphide (as pyrite; δ34S ~0‰), and dissolved water sulphate (δ34S ~3.2 ‰) consistently along the hot spring stream, indicating the presence of an active sulphur cycle, although not one dominated by sulphate reduction (e.g. very negative sulphide δ34S). This

Uranium budget of the Thames River, Ontario, Great Lakes Region: partitioning between dissolved and microorganism components

International Nuclear Information System (INIS)

Mann, H.; Fyfe, W.S.

1987-01-01

The average level of dissolved U in the Thames River of southern Ontario is 1.45 ± 0.61 ppb, representing about twice the global mean riverine U solute concentration of 0.6 ppb. Systematic seasonal variations of dissolved U occur, peaking over the fall and winter months September-February, contrasting with depressed levels during the spring and summer: the winter and fall peaks correlate with higher discharge rates during thawing and rainfall maxima respectively, and the peak during thawing is probably indigenous to a transient melt-water surge. Whereas variations in discharge rate of up to 100-fold occur over a year, the magnitude of differences in aqueous U are at most a factor of 2, such that the U supply to the river is over-compensated for by extra water in the river system. Algae are abundant in Thames River waters at all seasons, constituting a significant fraction of the suspended > 0.45-μm particulates: they have enhanced U contents of 10 3 -10 5 times that of the river water, and an average of 28,000 ppb U. The average weight of suspended algae in river water is 9.7 mg l -1 (± 6.6 1σ), and these microorganisms carry ∼ 15% of the total riverine U flux. A correlation exists between levels of dissolved U and the U abundance of suspended algae, implying a relatively uniform partitioning of U between algae and water of 2x10 4 . 13 refs.; 7 figs.; 2 tabs

Speciative determination of total V and dissolved inorganic vanadium species in environmental waters by catalytic–kinetic spectrophotometric method

Directory of Open Access Journals (Sweden)

Ramazan Gürkan

2017-02-01

Full Text Available A kinetic determination of V(V as a catalyst was spectrophotometrically performed by using the indicator reaction of Gallamine blue (GB+ and bromate at pH 2.0. The reaction was followed by measuring absorbance change for a fixed-time of 3 min at 537 nm. The variables such as reagent concentration, pH, buffer concentration, ionic strength and temperature were optimized to improve the selectivity and sensitivity. Under the optimized conditions, the determination of V(V was performed in the range 1–100 μg L−1 with limits of detection and quantification of 0.31 and 0.94 μg L−1. The developed kinetic method is sufficiently sensitive, selective and simple. It was successfully applied to the speciative determination of total V and inorganic dissolved vanadium species, V(V and V(IV in environmental water samples. The oxidizing property of permanganate is used to differentiate between V(IV and V(V species. The V(IV content was found by subtracting the V(V content from those of total V. The recovery is above 95% for V(V spiked samples. Additionally, the accuracy was validated by analysis of a certified water sample, CRM TMDA-53.3, and the results were in good agreement with the certified value.

Effects of resuspension on benthic fluxes of oxygen, nutrients, dissolved inorganic carbon, iron and manganese in the Gulf of Finland, Baltic Sea

NARCIS (Netherlands)

Almroth, E.; Tengberg, A.; Andersson, J.H.; Pakhomova, S.; Hall, P.O.J.

2009-01-01

The effect of resuspension on benthic fluxes of oxygen (O2), ammonium (NH4+), nitrate (NO3-), phosphate (PO43-), silicate (Si(OH)4), dissolved inorganic carbon (DIC), total dissolved iron (Fe) and total dissolved manganese (Mn) was studied at three different stations in the Gulf of Finland (GoF),

Spatiotemporal variation of dissolved carbohydrates and amino acids in Jiaozhou Bay, China

Science.gov (United States)

Shi, Di; Yang, Guipeng; Sun, Yan; Wu, Guanwei

2017-03-01

Surface seawater samples were collected from Jiaozhou Bay, China, during six cruises (March-May 2010, September-November 2010) to study the distribution of dissolved organic matter including dissolved organic carbon (DOC), total dissolved carbohydrates, namely monosaccharides (MCHO) and polysaccharides (PCHO) and total hydrolysable amino acids. These included dissolved free amino acids (DFAA) and combined amino acids (DCAA). The goal was to investigate possible relationships between these dissolved organic compounds and environmental parameters. During spring, the concentrations of MCHO and PCHO were 9.6 (2.8-22.6) and 11.0 (2.9-42.5) μmol C/L, respectively. In autumn, MCHO and PCHO were 9.1 (2.6-27.0) and 10.8 (2.4-25.6) μmol C/L, respectively. The spring concentrations of DFAA and DCAA were 1.7 (1.1-4.1) and 7.6 (1.1-31.0) μmol C/L, respectively, while in autumn, DFAA and DCAA were 2.3 (1.1-8.0) and 3.3 (0.6-7.2) μmol C/L, respectively. Among these compounds, the concentrations of PCHO were the highest, accounting for nearly a quarter of the DOC, followed by MCHO, DCAA and DFAA. The concentrations of the organic compounds exhibited a decreasing trend from the coastal to the central regions of the bay. A negative correlation between concentrations of DOC and salinity in each cruise suggested that riverine inputs around the bay have an important impact on the distribution of DOC in the surface water. A significant positive correlation was found between DOC and total bacteria count in spring and autumn, suggesting bacteria play an important role in the marine carbon cycle.

Dissolved organic matter removal using magnetic anion exchange resin treatment on biological effluent of textile dyeing wastewater.

Science.gov (United States)

Fan, Jun; Li, Haibo; Shuang, Chendong; Li, Wentao; Li, Aimin

2014-08-01

This study investigated the removal of dissolved organic matter (DOM) from real dyeing bio-treatment effluents (DBEs) with the use of a novel magnetic anion exchange resin (NDMP). DOMs in two typical DBEs were fractionized using DAX-8/XAD-4 resin and ultrafiltration membranes. The hydrophilic fractions and the low molecular weight (MW) (50%) of DOMs for the two effluents. The hydrophilic and low MW fractions of both effluents were the greatest contributors of specific UV254 absorbance (SUVA254), and the SUVA254 of DOM fractions decreased with hydrophobicity and MW. Two DBEs exhibited acute and chronic biotoxicities. Both acute and chronic toxicities of DOM fractions increased linearly with the increase of SUVA254 value. Kinetics of dissolved organic carbon (DOC) removal via NDMP treatment was performed by comparing it with that of particle active carbon (PAC). Results indicated that the removal of DOC from DBEs via NDMP was 60%, whereas DOC removals by PAC were lower than 15%. Acidic organics could be significantly removed with the use of NDMP. DOM with large MW in DBE could be removed significantly by using the same means. Removal efficiency of NDMP for DOM decreased with the decrease of MW. Compared with PAC, NDMP could significantly reduce the acute and chronic bio-toxicities of DBEs. NaCl/NaOH mixture regenerants, with selected concentrations of 10% NaCl (m/m)/1% NaOH (m/m), could improve desorption efficiency. Copyright © 2014. Published by Elsevier B.V.

Basin-scale transport of hydrothermal dissolved metals across the South Pacific Ocean.

Science.gov (United States)

Resing, Joseph A; Sedwick, Peter N; German, Christopher R; Jenkins, William J; Moffett, James W; Sohst, Bettina M; Tagliabue, Alessandro

2015-07-09

Hydrothermal venting along mid-ocean ridges exerts an important control on the chemical composition of sea water by serving as a major source or sink for a number of trace elements in the ocean. Of these, iron has received considerable attention because of its role as an essential and often limiting nutrient for primary production in regions of the ocean that are of critical importance for the global carbon cycle. It has been thought that most of the dissolved iron discharged by hydrothermal vents is lost from solution close to ridge-axis sources and is thus of limited importance for ocean biogeochemistry. This long-standing view is challenged by recent studies which suggest that stabilization of hydrothermal dissolved iron may facilitate its long-range oceanic transport. Such transport has been subsequently inferred from spatially limited oceanographic observations. Here we report data from the US GEOTRACES Eastern Pacific Zonal Transect (EPZT) that demonstrate lateral transport of hydrothermal dissolved iron, manganese, and aluminium from the southern East Pacific Rise (SEPR) several thousand kilometres westward across the South Pacific Ocean. Dissolved iron exhibits nearly conservative (that is, no loss from solution during transport and mixing) behaviour in this hydrothermal plume, implying a greater longevity in the deep ocean than previously assumed. Based on our observations, we estimate a global hydrothermal dissolved iron input of three to four gigamoles per year to the ocean interior, which is more than fourfold higher than previous estimates. Complementary simulations with a global-scale ocean biogeochemical model suggest that the observed transport of hydrothermal dissolved iron requires some means of physicochemical stabilization and indicate that hydrothermally derived iron sustains a large fraction of Southern Ocean export production.

Earthworms change the quantity and composition of dissolved organic carbon and reduce greenhouse gas emissions during composting

DEFF Research Database (Denmark)

Nigatu, Abebe Nigussie; Bruun, Sander; de Neergaard, Andreas

2017-01-01

Dissolved organic carbon (DOC) has recently been proposed as an indicator of compost stability. We assessed the earthworms' effect on DOC content and composition during composting, and linked compost stability to greenhouse gas emissions and feeding ratio. Earthworms reduced total DOC content......, indicating larger stability of vermicompost than of thermophilic compost. The concentrations of humic acid and fulvic acid were reduced by earthworms, whereas there was no significant effect on hydrophobic neutrals and hydrophilics. The humic acid fraction was depleted more quickly than the other compounds......, indicating humic acid degradation during composting. The optimum feeding ratio decreased DOC content compared to the high feeding ratio. The lowest N2O emissions were also observed at the optimum feeding ratio. Our study confirmed the use of DOC content and composition as an indicator of compost stability...

Comparison of the chemical composition of dissolved organic matter in three lakes in Minnesota

Science.gov (United States)

Cao, Xiaoyan; Aiken, George R.; Butler, Kenna D.; Mao, Jingdong; Schmidt-Rohr, Klaus

2018-01-01

New information on the chemical composition of dissolved organic matter (DOM) in three lakes in Minnesota has been gained from spectral editing and two-dimensional nuclear magnetic resonance (NMR) methods, indicating the effects of lake hydrological settings on DOM composition. Williams Lake (WL), Shingobee Lake (SL), and Manganika Lake (ML) had different source inputs, and the lake water residence time (WRT) of WL was markedly longer than that of SL and ML. The hydrophobic organic acid (HPOA) and transphilic organic acid (TPIA) fractions combined comprised >50% of total DOM in these lakes, and contained carboxyl-rich alicyclic molecules (CRAM), aromatics, carbohydrates, and N-containing compounds. The previously understudied TPIA fractions contained fewer aromatics, more oxygen-rich CRAM, and more N-containing compounds compared to the corresponding HPOA. CRAM represented the predominant component in DOM from all lakes studied, and more so in WL than in SL and ML. Aromatics including lignin residues and phenols decreased in relative abundances from ML to SL and WL. Carbohydrates and N-containing compounds were minor components in both HPOA and TPIA and did not show large variations among the three lakes. The increased relative abundances of CRAM in DOM from ML, SL to WL suggested the selective preservation of CRAM with increased residence time.

Responsiveness of soil nitrogen fractions and bacterial communities to afforestation in the Loess Hilly Region (LHR) of China

Science.gov (United States)

Ren, Chengjie; Sun, Pingsheng; Kang, Di; Zhao, Fazhu; Feng, Yongzhong; Ren, Guangxin; Han, Xinhui; Yang, Gaihe

2016-06-01

In the present paper, we investigated the effects of afforestation on nitrogen fractions and microbial communities. A total of 24 soil samples were collected from farmland (FL) and three afforested lands, namely Robinia pseudoacacia L (RP), Caragana korshinskii Kom (CK), and abandoned land (AL), which have been arable for the past 40 years. Quantitative PCR and Illumina sequencing of 16S rRNA genes were used to analyze soil bacterial abundance, diversity, and composition. Additionally, soil nitrogen (N) stocks and fractions were estimated. The results showed that soil N stock, N fractions, and bacterial abundance and diversity increased following afforestation. Proteobacteria, Acidobacteria, and Actinobacteria were the dominant phyla of soil bacterial compositions. Overall, soil bacterial compositions generally changed from Actinobacteria (Acidobacteria)-dominant to Proteobacteria-dominant following afforestation. Soil N fractions, especially for dissolved organic nitrogen (DON), were significantly correlated with most bacterial groups and bacterial diversity, while potential competitive interactions between Proteobacteria (order Rhizobiales) and Cyanobacteria were suggested. In contrast, nitrate nitrogen (NO3--N) influenced soil bacterial compositions less than other N fractions. Therefore, the present study demonstrated that bacterial diversity and specific species respond to farmland-to-forest conversion and hence have the potential to affect N dynamic processes in the Loess Plateau.

PREDICTION OF TOTAL DISSOLVED GAS EXCHANGE AT HYDROPOWER DAMS

Energy Technology Data Exchange (ETDEWEB)

Hadjerioua, Boualem [ORNL; Pasha, MD Fayzul K [ORNL; Stewart, Kevin M [ORNL; Bender, Merlynn [Bureau of Reclamation; Schneider, Michael L. [U.S. Army Corps of Engineers

2012-07-01

Total dissolved gas (TDG) supersaturation in waters released at hydropower dams can cause gas bubble trauma in fisheries resulting in physical injuries and eyeball protrusion that can lead to mortality. Elevated TDG pressures in hydropower releases are generally caused by the entrainment of air in spillway releases and the subsequent exchange of atmospheric gasses into solution during passage through the stilling basin. The network of dams throughout the Columbia River Basin (CRB) are managed for irrigation, hydropower production, flood control, navigation, and fish passage that frequently result in both voluntary and involuntary spillway releases. These dam operations are constrained by state and federal water quality standards for TDG saturation which balance the benefits of spillway operations designed for Endangered Species Act (ESA)-listed fisheries versus the degradation to water quality as defined by TDG saturation. In the 1970s, the United States Environmental Protection Agency (USEPA), under the federal Clean Water Act (Section 303(d)), established a criterion not to exceed the TDG saturation level of 110% in order to protect freshwater and marine aquatic life. The states of Washington and Oregon have adopted special water quality standards for TDG saturation in the tailrace and forebays of hydropower facilities on the Columbia and Snake Rivers where spillway operations support fish passage objectives. The physical processes that affect TDG exchange at hydropower facilities have been studied throughout the CRB in site-specific studies and routine water quality monitoring programs. These data have been used to quantify the relationship between project operations, structural properties, and TDG exchange. These data have also been used to develop predictive models of TDG exchange to support real-time TDG management decisions. These empirically based predictive models have been developed for specific projects and account for both the fate of spillway and

Total dissolved gas prediction and optimization in RiverWare

Energy Technology Data Exchange (ETDEWEB)

Stewart, Kevin M. [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Witt, Adam M. [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Hadjerioua, Boualem [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

2015-09-01

Management and operation of dams within the Columbia River Basin (CRB) provides the region with irrigation, hydropower production, flood control, navigation, and fish passage. These various system-wide demands can require unique dam operations that may result in both voluntary and involuntary spill, thereby increasing tailrace levels of total dissolved gas (TDG) which can be fatal to fish. Appropriately managing TDG levels within the context of the systematic demands requires a predictive framework robust enough to capture the operationally related effects on TDG levels. Development of the TDG predictive methodology herein attempts to capture the different modes of hydro operation, thereby making it a viable tool to be used in conjunction with a real-time scheduling model such as RiverWare. The end result of the effort will allow hydro operators to minimize system-wide TDG while meeting hydropower operational targets and constraints. The physical parameters such as spill and hydropower flow proportions, accompanied by the characteristics of the dam such as plant head levels and tailrace depths, are used to develop the empirically-based prediction model. In the broader study, two different models are developed a simplified and comprehensive model. The latter model incorporates more specific bubble physics parameters for the prediction of tailrace TDG levels. The former model is presented herein and utilizes an empirically based approach to predict downstream TDG levels based on local saturation depth, spillway and powerhouse flow proportions, and entrainment effects. Representative data collected from each of the hydro projects is used to calibrate and validate model performance and the accuracy of predicted TDG uptake. ORNL, in conjunction with IIHR - Hydroscience & Engineering, The University of Iowa, carried out model adjustments to adequately capture TDG levels with respect to each plant while maintaining a generalized model configuration. Validation results

Fractionated total body irradiation and autologous bone marrow transplantation in dogs: Hemopoietic recovery after various marrow cell doses

International Nuclear Information System (INIS)

Bodenburger, U.; Kolb, H.J.; Thierfelder, S.; Netzel, B.; Schaeffer, E.; Kolb, H.

1980-01-01

Hemopoietic recovery was studied in dogs given 2400 R fractionated total body irradiation within one week and graded doses of cryopreserved autologous bone marrow. Complete hemopoietic recovery including histology was observed after this dose and sufficient doses of marrow cells. Doses of more than 5.5 x 10 7 mononuclear marrow cells/kg body weight were sufficient for complete recovery in all dogs, 1.5 to 5.5 x 10 7 cells/kg were effective in some of the dogs and less than 1.5 x 10 7 cells/kg were insufficient for complete recovery. Similarly, more than 30000 CFUsub(c)/kg body weight were required for hemopoietic recovery. The optimal marrow cell dose which has been defined as the minimal dose required for the earliest possible recovery of leukocyte and platelet counts was 7-8 x 10 7 mononuclear marrow cells/kg body weight. It has been concluded that fractionated total body irradiation with 2400 R dose not require greater doses of marrow cells for hemopoietic reconstitution than lower single doses and that the hemopoietic microenvironment is not persistently disturbed after this dose. (author)

Decrease of concentration and colloidal fraction of organic carbon and trace elements in response to the anomalously hot summer 2010 in a humic boreal lake.

Science.gov (United States)

Shirokova, L S; Pokrovsky, O S; Moreva, O Yu; Chupakov, A V; Zabelina, S A; Klimov, S I; Shorina, N V; Vorobieva, T Ya

2013-10-01

The colloidal distribution and size fractionation of organic carbon (OC), major elements and trace elements (TE) were studied in a seasonally stratified, organic-rich boreal lake, Lake Svyatoe, located in the European subarctic zone (NW Russia, Arkhangelsk region). This study took place over the course of 4 years in both winter and summer periods using an in situ dialysis technique (1 kDa, 10 kDa and 50 kDa) and traditional frontal filtration and ultrafiltration (5, 0.22 and 0.025 μm). We observed a systematic difference in dissolved elements and colloidal fractions between summer and winter periods with the highest proportion of organic and organo-ferric colloids (1 kDa-0.22 μm) observed during winter periods. The anomalously hot summer of 2010 in European Russia produced surface water temperatures of approximately 30°C, which were 10° above the usual summer temperatures and brought about crucial changes in element speciation and size fractionation. In August 2010, the concentration of dissolved organic carbon (DOC) decreased by more than 30% compared to normal period, while the relative proportion of organic colloids decreased from 70-80% to only 20-30% over the full depth of the water column. Similarly, the proportion of colloidal Fe decreased from 90-98% in most summers and winters to approximately 60-70% in August 2010. During this hot summer, measurable and significant (>30% compared to other periods) decreases in the colloidal fractions of Ca, Mg, Sr, Ba, Al, Ti, Ni, As, V, Co, Y, all rare earth elements (REEs), Zr, Hf, Th and U were also observed. In addition, dissolved (organic matter by heterotrophic aerobic bacterioplankton and 3) photo-degradation of DOM and photo-chemical liberation of organic-bound TE. While the first process may have caused significant decreases in the total dissolved concentration of micronutrients (a factor of 2 to 5 for Cr, Mn, Fe, Ni, Cu, Zn and Cd and a factor of >100 for Co), the second and third factors could have brought

Effect of a dam on the optical properties of different-sized fractions of dissolved organic matter in a mid-subtropical drinking water source reservoir.

Science.gov (United States)

Sun, Qiyuan; Jiang, Juan; Zheng, Yuyi; Wang, Feifeng; Wu, Chunshan; Xie, Rong-Rong

2017-11-15

The presence of a dam on a river is believed to have a key role in affecting changes in the components of the chromophoric dissolved organic matter (CDOM) in reservoirs. However, questions remain about the mechanisms that control these changes. In this study, we used tangential ultrafiltration, fluorescence spectrum and phytoplankton cell density detection to explore the impacts of a dam on the CDOM components in the Shanzai Reservoir, a source of drinking water. The results demonstrated each CDOM size fraction comprised two main components, namely C1 (protein-like substance) and C2 (humic-like substance). The C1 content had a higher value in areas with slow flow than in the normal river channel, while the C2 contents were generally stable in the flow direction. The topography of the reservoir site affected the structure of the CDOM components based on changes in the hydraulic conditions caused by the dam. The variations in the CDOM components, hydraulic parameters and fluorescence indices in the river flow direction indicated that the contribution of the phytoplankton to the CDOM content increased as the distance to the dam decreased, phytoplankton metabolism enhanced C1 content of the 1-10kDa molecular weights range fraction. Further, the contributions of different phytoplankton biomass to C1 proved that the dam changed the hydraulic conditions, had secondary effects on the metabolism of the phytoplankton, and resulted in changes in the structure of the CDOM components. Copyright © 2017 Elsevier B.V. All rights reserved.

Advanced characterization of dissolved organic matter released by bloom-forming marine algae

KAUST Repository

Rehman, Zahid Ur

2017-06-01

Algal organic matter (AOM), produced by marine phytoplankton during bloom periods, may adversely affect the performance of membrane processes in seawater desalination. The polysaccharide fraction of AOM has been related to (bio)fouling in micro-filtration and ultrafiltration, and reverse osmosis membranes. However, so far, the chemical structure of the polysaccharides released by bloom-forming algae is not well understood. In this study, dissolved fraction of AOM produced by three algal species (Chaetoceros affinis, Nitzschia epithemoides and Hymenomonas spp.) was characterized using liquid chromatography–organic carbon detection (LC-OCD) and fluorescence spectroscopy. Chemical structure of polysaccharides isolated from the AOM solutions at stationary phase was analyzed using proton nuclear magnetic resonance (H-NMR). The results showed that production and composition of dissolved AOM varied depending on algal species and their growth stage. AOM was mainly composed of biopolymers (BP; i.e., polysaccharides and proteins [PN]), but some refractory substances were also present.H-NMR spectra confirmed the predominance of carbohydrates in all samples. Furthermore, similar fingerprints were observed for polysaccharides of two diatom species, which differed considerably from that of coccolithophores. Based on the findings of this study,H-NMR could be used as a method for analyzing chemical profiles of algal polysaccharides to enhance the understanding of their impact on membrane fouling.

Effects of long-term land use change on dissolved carbon characteristics in the permafrost streams of northeast China.

Science.gov (United States)

Guo, Yuedong; Song, Changchun; Wan, Zhongmei; Tan, Wenwen; Lu, Yongzheng; Qiao, Tianhua

2014-11-01

Permafrost soils act as large sinks of organic carbon but are highly sensitive to interference such as changes in land use, which can greatly influence dissolved carbon loads in streams. This study examines the effects of long-term land reclamation on seasonal concentrations of dissolved carbons in the upper reaches of the Nenjiang River, northeast China. A comparison of streams in natural and agricultural systems shows that the dissolved organic carbon (DOC) concentration is much lower in the agricultural stream (AG) than in the two natural streams (WAF, wetland dominated; FR, forest dominated), suggesting that land use change is associated with reduced DOC exporting capacity. Moreover, the fluorescence indexes and the ratio of dissolved carbon to nitrogen also differ greatly between the natural and agricultural streams, indicating that the chemical characteristics and the origin of the DOC released from the whole reaches are also altered to some extent. Importantly, the exporting concentration of dissolved inorganic carbon (DIC) and its proportion of total dissolved carbon (TDC) substantially increase following land reclamation, which would largely alter the carbon cycling processes in the downstream fluvial system. Although the strong association between the stream discharge and the DOC concentration was unchanged, the reduction in total soil organic carbon following land reclamation led to remarkable decline of the total flux and exporting coefficient of the dissolved carbons. The results suggest that dissolved carbons in permafrost streams have been greatly affected by changes in land use since the 1970s, and the changes in the concentration and chemical characteristics of dissolved carbons will last until the alteration in both the traditional agriculture pattern and the persistent reclamation activities.

Silicon isotope fractionation during silica precipitation from hot-spring waters

Science.gov (United States)

Geilert, Sonja; Vroon, Pieter; Keller, Nicole; Gudbrnadsson, Snorri; Stefánsson, Andri; van Bergen, Manfred

2014-05-01

Hot-spring systems in the Geysir geothermal area, Iceland, have been studied to explore silicon isotope fractionation in a natural setting where sinter deposits are actively formed over a temperature interval between 20° and 100° C. The SiO2(aq)concentrations in spring and stream waters range between 290 and 560ppm and stay relatively constant along downstream trajectories, irrespective of significant cooling gradients. The waters are predominantly oversaturated in amorphous silica at the temperatures measured in the field. Correlations between the saturation indices, temperature and amounts of evaporative water loss suggest that cooling and evaporation are the main causes of subaqueous silica precipitation. The δ30Si values of dissolved silica in spring water and outflowing streams average around +1o probably due to the small quantities of instantaneously precipitating silica relative to the dissolved amount. Siliceous sinters, in contrast, range between -0.1o to -4.0o consistent with a preferred incorporation of the light silicon isotope and with values for precipitated silica becoming more negative with downstream decreasing temperatures. Larger fractionation magnitudes are inversely correlated with the precipitation rate, which itself is dependent on temperature, saturation state and the extent of a system. The resulting magnitudes of solid-fluid isotopic fractionation generally decline from -3.5o at 10° C to -2.0o at 90° C. These values confirm a similar relationship between fractionation magnitude and temperature that we found in laboratory-controlled silica-precipitation experiments. However, a relatively constant offset of ca. -2.9o between field and experimental fractionation values indicates that temperature alone cannot be responsible for the observed shifts. We infer that precipitation kinetics are a prominent control of silicon isotope fractionation in aqueous environments, whereby the influence of the extent of the system on the precipitation

Novel insights from NMR spectroscopy into seasonal changes in the composition of dissolved organic matter exported to the Bering Sea by the Yukon River

Science.gov (United States)

Cao, Xiaoyan; Aiken, George R.; Spencer, Robert G. M.; Butler, Kenna D.; Mao, Jingdong; Schmidt-Rohr, Klaus

2016-01-01

Seasonal (spring freshet, summer–autumn, and winter) variability in the chemical composition of dissolved organic matter (DOM) from the Yukon River was determined using advanced one- and two-dimensional (2D) solid-state NMR spectroscopy, coupled with isotopic measurements and UV–visible spectroscopy. Analyses were performed on two major DOM fractions, the hydrophobic organic acid (HPOA) and transphilic organic acid (TPIA) fractions obtained using XAD resins. Together these two fractions comprised 64–74% of the total DOM. Carboxyl-rich alicyclic molecules (CRAM) accounted for the majority of carbon atoms in the HPOA (63–77%) and TPIA (54–78%) samples, and more so in winter and summer than in spring samples. 2D and selective NMR data revealed association of abundant nonprotonated O-alkyl and quaternary alkyl C (OCnp, OCnpO and Cq, 13–17% of HPOA and 15–20% of TPIA) and isolated O–CH structures with CRAM, which were not recognized in previous studies. Spectral editing and 2D NMR allowed for the discrimination of carbohydrate-like O-alkyl C from non-carbohydrate O-alkyl C. Whereas two spring freshet TPIA samples contained carbohydrate clusters such as carboxylated carbohydrates (16% and 26%), TPIA samples from other seasons or HPOA samples mostly had small amounts (<8%) of sugar rings dispersed in a nonpolar alkyl environment. Though nonprotonated aromatic C represented the largest fraction of aromatic C in all HPOA/TPIA isolates, only a small fraction (∼5% in HPOA and 3% in TPIA) was possibly associated with dissolved black carbon. Our results imply a relatively stable portion of DOM exported by the Yukon River across different seasons, due to the predominance of CRAM and their associated nonprotonated C–O and O–C–O structures, and elevated reactivity (bio- and photo-lability) of spring DOM due to the presence of terrestrial inputs enriched in carbohydrates and aromatic structures.

Tritium/protium fractionation near and inside DNA

International Nuclear Information System (INIS)

Baumgartner, F.; Kim, M.A.

2000-01-01

The fractionation factor of tritium between water and DNA as well as between water and the first hydration shell of DNA is determined. For this purpose the sublimation kinetics of water from DNA dissolved in water were determined at -200 deg C and tritium was measured in the remaining water free DNA. The last sublimating water fractions showed a tritium level of about 1.4, the residual water free DNA about 1.9 units above the bulk water. The tritium accumulation inside and near DNA is attributed to the thermodynamic triton-proton exchange isotope effect existing between the strong hydrogen bridges of water and weaker hydrogen bridges as well as inside DNA as between the first hydration shell and DNA. (author)

Dissolved organic nitrogen dynamics in the North Sea: A time series analysis (1995-2005)

Science.gov (United States)

Van Engeland, T.; Soetaert, K.; Knuijt, A.; Laane, R. W. P. M.; Middelburg, J. J.

2010-09-01

Dissolved organic nitrogen (DON) dynamics in the North Sea was explored by means of long-term time series of nitrogen parameters from the Dutch national monitoring program. Generally, the data quality was good with little missing data points. Different imputation methods were used to verify the robustness of the patterns against these missing data. No long-term trends in DON concentrations were found over the sampling period (1995-2005). Inter-annual variability in the different time series showed both common and station-specific behavior. The stations could be divided into two regions, based on absolute concentrations and the dominant times scales of variability. Average DON concentrations were 11 μmol l -1 in the coastal region and 5 μmol l -1 in the open sea. Organic fractions of total dissolved nitrogen (TDN) averaged 38 and 71% in the coastal zone and open sea, respectively, but increased over time due to decreasing dissolved inorganic nitrogen (DIN) concentrations. In both regions intra-annual variability dominated over inter-annual variability, but DON variation in the open sea was markedly shifted towards shorter time scales relative to coastal stations. In the coastal zone a consistent seasonal DON cycle existed with high values in spring-summer and low values in autumn-winter. In the open sea seasonality was weak. A marked shift in the seasonality was found at the Dogger Bank, with DON accumulation towards summer and low values in winter prior to 1999, and accumulation in spring and decline throughout summer after 1999. This study clearly shows that DON is a dynamic actor in the North Sea and should be monitored systematically to enable us to understand fully the functioning of this ecosystem.

Origins and bioavailability of dissolved organic matter in groundwater

Science.gov (United States)

Shen, Yuan; Chapelle, Francis H.; Strom, Eric W.; Benner, Ronald

2015-01-01

Dissolved organic matter (DOM) in groundwater influences water quality and fuels microbial metabolism, but its origins, bioavailability and chemical composition are poorly understood. The origins and concentrations of dissolved organic carbon (DOC) and bioavailable DOM were monitored during a long-term (2-year) study of groundwater in a fractured-rock aquifer in the Carolina slate belt. Surface precipitation was significantly correlated with groundwater concentrations of DOC, bioavailable DOM and chromophoric DOM, indicating strong hydrological connections between surface and ground waters. The physicochemical and biological processes shaping the concentrations and compositions of DOM during its passage through the soil column to the saturated zone are conceptualized in the regional chromatography model. The model provides a framework for linking hydrology with the processes affecting the transformation, remineralization and microbial production of DOM during passage through the soil column. Lignin-derived phenols were relatively depleted in groundwater DOM indicating substantial removal in the unsaturated zone, and optical properties of chromophoric DOM indicated lower molecular weight DOM in groundwater relative to surface water. The prevalence of glycine, γ-aminobutyric acid, and d-enantiomers of amino acids indicated the DOM was highly diagenetically altered. Bioassay experiments were used to establish DOC-normalized yields of amino acids as molecular indicators of DOM bioavailability in groundwater. A relatively small fraction (8 ± 4 %) of DOC in groundwater was bioavailable. The relatively high yields of specific d-enantiomers of amino acids indicated a substantial fraction (15–34 %) of groundwater DOC was of bacterial origin.

Size-fractionation of groundwater arsenic in alluvial aquifers of West Bengal, India: the role of organic and inorganic colloids.

Science.gov (United States)

Majumder, Santanu; Nath, Bibhash; Sarkar, Simita; Chatterjee, Debashis; Roman-Ross, Gabriela; Hidalgo, Manuela

2014-01-15

Dissolved organic carbon (DOC) and Fe mineral phases are known to influence the mobility of arsenic (As) in groundwater. Arsenic can be associated with colloidal particles containing organic matter and Fe. Currently, no data is available on the dissolved phase/colloidal association of As in groundwater of alluvial aquifers in West Bengal, India. This study investigated the fractional distribution of As (and other metals/metalloids) among the particulate, colloidal and dissolved phases in groundwater to decipher controlling behavior of organic and inorganic colloids on As mobility. The result shows that 83-94% of As remained in the 'truly dissolved' phases (i.e., 0.05 μm size) colloidal particles, which indicates the close association of As with larger Fe-rich inorganic colloids. In smaller (i.e., <0.05 μm size) colloidal particles strong positive correlation is observed between As and DOC (r(2)=0.85), which highlights the close association of As with smaller organic colloids. As(III) is mainly associated with larger inorganic colloids, whereas, As(V) is associated with smaller organic/organometallic colloids. Scanning Electron Microscopy and Energy Dispersive X-ray spectroscopy confirm the association of As with DOC and Fe mineral phases suggesting the formation of dissolved organo-Fe complexes and colloidal organo-Fe oxide phases. Attenuated total reflectance-Fourier transform infrared spectroscopy further confirms the formation of As-Fe-NOM organometallic colloids, however, a detailed study of these types of colloids in natural waters is necessary to underpin their controlling behavior. © 2013 Elsevier B.V. All rights reserved.

Characterization of dissolved organic matter during landfill leachate treatment by sequencing batch reactor, aeration corrosive cell-Fenton, and granular activated carbon in series

International Nuclear Information System (INIS)

Bu Lin; Wang Kun; Zhao Qingliang; Wei Liangliang; Zhang Jing; Yang Junchen

2010-01-01

Landfill leachate is generally characterized as a complex recalcitrant wastewater containing high concentration of dissolved organic matter (DOM). A combination of sequencing batch reactor (SBR) + aeration corrosive cell-Fenton (ACF) + granular activated carbon (GAC) adsorption in series was proposed for the purpose of removing pollutants in the leachate. Fractionation was also performed to investigate the composition changes and characteristics of the leachate DOM in each treatment process. Experimental results showed that organic matter, in terms of chemical oxygen demand (COD), 5-day biological oxygen demand (BOD 5 ), and dissolved organic carbon (DOC), was reduced by 97.2%, 99.1%, and 98.7%, respectively. To differentiate the DOM portions, leachates were separated into five fractions by XAD-8 and XAD-4 resins: hydrophobic acid (HPO-A), hydrophobic neutral (HPO-N), transphilic acid (TPI-A), transphilic neutral (TPI-N), and hydrophilic fraction (HPI). The predominant fraction in the raw leachate was HPO-A (36% of DOC), while the dominant fraction in the final effluent was HPI (53% of DOC). Accordingly, macromolecules were degraded to simpler ones in a relatively narrow range below 1000 Da. Spectral and chromatographic analyses also showed that most humic-like substances in all fractions were effectively removed during the treatments and led to a simultaneous decrease in aromaticity.

Characterization of dissolved organic matter during landfill leachate treatment by sequencing batch reactor, aeration corrosive cell-Fenton, and granular activated carbon in series

Energy Technology Data Exchange (ETDEWEB)

Bu Lin [School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090 (China); Wang Kun [State Key Laboratory of Urban Water Resources and Environment (SKLUWRE), Harbin Institute of Technology, Harbin 150090 (China); School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090 (China); Zhao Qingliang, E-mail: zhql1962@yahoo.com.cn [State Key Laboratory of Urban Water Resources and Environment (SKLUWRE), Harbin Institute of Technology, Harbin 150090 (China); School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090 (China); Wei Liangliang; Zhang Jing; Yang Junchen [School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090 (China)

2010-07-15

Landfill leachate is generally characterized as a complex recalcitrant wastewater containing high concentration of dissolved organic matter (DOM). A combination of sequencing batch reactor (SBR) + aeration corrosive cell-Fenton (ACF) + granular activated carbon (GAC) adsorption in series was proposed for the purpose of removing pollutants in the leachate. Fractionation was also performed to investigate the composition changes and characteristics of the leachate DOM in each treatment process. Experimental results showed that organic matter, in terms of chemical oxygen demand (COD), 5-day biological oxygen demand (BOD{sub 5}), and dissolved organic carbon (DOC), was reduced by 97.2%, 99.1%, and 98.7%, respectively. To differentiate the DOM portions, leachates were separated into five fractions by XAD-8 and XAD-4 resins: hydrophobic acid (HPO-A), hydrophobic neutral (HPO-N), transphilic acid (TPI-A), transphilic neutral (TPI-N), and hydrophilic fraction (HPI). The predominant fraction in the raw leachate was HPO-A (36% of DOC), while the dominant fraction in the final effluent was HPI (53% of DOC). Accordingly, macromolecules were degraded to simpler ones in a relatively narrow range below 1000 Da. Spectral and chromatographic analyses also showed that most humic-like substances in all fractions were effectively removed during the treatments and led to a simultaneous decrease in aromaticity.

Spatial and seasonal variability of fractionated phytoplankton biomass and primary production in the frontal region of the Northern Adriatic Sea

Directory of Open Access Journals (Sweden)

M.R. VADRUCCI

2005-06-01

Full Text Available Spatial and seasonal patterns of variation of fractionated phytoplankton biomass and primary production and their relationships with nutrient concentrations were analyzed along an inshore - offshore gradient and in relation to the presence of a frontal system in the Northern Adriatic Sea. Sampling was carried out in winter and summer during four oceanographic cruises (June 1996 and 1997, February 1997 and 1998 as part of the PRISMA II project. Water samples for determining nutrient concentrations, phytoplankton biomass (as Chla and primary production (as 14 C assimilation were collected at five optical depths. Sampling stations were located along 2 or 4 parallel transects arranged perpendicularly to the shoreline and the frontal system. The transects were located at such a distance from the coast that the frontal system crossed them at their halfway point. Total dissolved nitrogen (TDN and total dissolved phosphorus concentrations (TDP were 12.41 ± 3 .95 mM and 0.146 ± 0 .070 mM, respectively. The values in the two seasonal periods were similar, decreasing along the inshore-offshore gradient. Values for phytoplankton biomass and primary productionwere higher in the winter than the summer cruises, and decreased, in both seasonal periods, along the inshore / offshore gradient. Moreover, in both seasonal periods, picophytoplankton dominated both biomass and productivity, (56% and 44%, respectively at stations beyond the frontal system, while microphytoplankton was more important at stations inside it (44% and 44%, respectively. Total phytoplankton biomass and primary production were directly related to nutrient concentrations. Regarding size classes, significant patterns of variation with nutrients were observed particularly for biomass. The results indicate that the size structure and function of phytoplankton guilds seem to be mediated by nutrient inflow, as well as by competitive interaction among size fractions.

Simultaneous determination of uranium and plutonium in dissolver solution of irradiated fuel, using ID-TIMS. IRP-11

International Nuclear Information System (INIS)

Shah, Raju; Sasi Bhushan, K.; Govindan, R.; Alamelu, D.; Khodade, P.S.; Aggarwal, S.K.

2007-01-01

A simple sample preparation and simultaneous analysis method to determine uranium and plutonium from dissolver solution, employing the technique of Isotope Dilution Mass spectrometry has been demonstrated. The method used, co-elusion of Uranium and Plutonium from anion exchanger column after initial elution of major part of uranium in 1:5 HNO 3 in order to reduce the initial U/Pu ratio from 1000 to about 100-200 in the co-eluted fraction. Due to the availability of variable multi-collector system, different Faraday cups were adjusted to collect the different ion intensities corresponding to the different masses, during the simultaneous analysis of Uranium and Plutonium, loaded on Re double filament assembly. 233 U and PR grade Plutonium were used as spikes to determine Uranium and Plutonium from dissolver solution of irradiated fuel from research reactor. The possibility of getting the isotopic composition of uranium from the simultaneous analysis of co-eluted purified fraction of U and Pu from spiked aliquots is also explained. (author)

Effects of long-term Salix cultivation on total and plant-available contents of Cadmium in the soil - a pilot study

International Nuclear Information System (INIS)

Eriksson, Jan; Ledin, S.

1996-02-01

The aim of the project was to study how total and plant-available contents of Cadmium in the soil are affected by the large amounts of Cadmium that are removed during the harvesting of Salix. Eight long-term Salix plantations, 8-30 years old, were chosen. At each place soil samples were taken in 4 areas in the stands of Salix and in 4 neighbouring areas with comparable soil conditions, but without Salix (reference areas). Cd in three fractions of different bonding strength were determined in the soil samples. The fractions roughly correspond to the total concentration, the exchangeable fraction, and the fraction dissolved in the soil solution. The result showed a relatively minor effect of the Salix plantation on the total concentrations. In six of eight cases, however, the concentrations tended to be lower in the Salix plantations than in the reference areas. When consideration was given to certain pH differences, the exchangeable, and particularly the most soluble fraction, showed a clear tendency for concentrations to be lower in the Salix stands than in the reference areas.The concentrations in stem samples from growing stands were generally lower than those measured in harvest-mature stems in other studies. The concentrations in foliage were of the same magnitude as those in the stems, implying that there is an important return of Cd to the soil at leaf-fall. The negligible effect on the total content in the soil may depend on uptake occurring both in the topsoil and in the subsoil. Re-circulation via the leaves will also result in redistribution of Cd from the subsoil to the topsoil, compensating the uptake from the topsoil. The conclusion reached was that Salix cultivation results in a reduction of the plant-available Cd in the soil, but the effect is not concentrated to the topsoil. 13 refs, 5 tabs, 4 figs

Absorption spectroscopy of colored dissolved organic carbon in Georgia (USA rivers: the impact of molecular size distribution

Directory of Open Access Journals (Sweden)

Michelle McELVAINE

2003-02-01

Full Text Available Dissolved organic carbon (DOC was collected in six rivers that transect the coastal plain of Georgia in July 1999 and February 2000. DOC concentrations ranged from 4.9 to 40.7 g m-3 and from 7.1 to 40.5 g m-3, respectively. The absorption coefficient at 440 nm was highly correlated with DOC concentration, suggesting that the optical parameter may be utilized for rapid estimation of DOC in these waters. The isolated DOC was separated into fractions of operationally defined molecular size, using an ultrafiltration technique that yielded three fractions: 50 ("large" kilodalton. The smallest fraction was the most abundant (>50% in 4 rivers in July and in all rivers in February, and considerably more abundant than in previous years. The wavelength-dependent absorption of the total DOC and its fractions showed approximately uniform shape of a curve declining exponentially with the increase of wavelength. The average slope of logarithmically transformed curves was 0.0151 and 0.0159 nm-1, for the material collected in July and February, respectively and showed a dependence on DOC molecular size. In unfractionated DOC samples, the mass-specific light absorption determined at 440 nm was on average 0.33 m2 g-1 in July, and 0.26 m2 g-1 in February. The mass-specific absorption coefficient in all fractions ranged between 0.085 and 1.347 m2 g-1 in July and between 0.085 and 1.877 m2 g-1 in February, and was positively correlated with the molecular size of the measured samples. The results of the reported study clearly suggest that the specific absorption coefficient of the yellow substance is an outcome of the relative contribution of its different size fractions.

Uptake of allochthonous dissolved organic matter from soil and salmon in coastal temperate rainforest streams

Science.gov (United States)

Jason B. Fellman; Eran Hood; Richard T. Edwards; Jeremy B. Jones

2009-01-01

Dissolved organic matter (DOM) is an important component of aquatic food webs. We compare the uptake kinetics for NH4-N and different fractions of DOM during soil and salmon leachate additions by evaluating the uptake of organic forms of carbon (DOC) and nitrogen (DON), and proteinaceous DOM, as measured by parallel factor (PARAFAC) modeling of...

Dynamics of dissolved organic carbon in a stream during a quarter century of forest succession

Science.gov (United States)

Judy L. Meyer; Jackson Webster; Jennifer Knoepp; E.F. Benfield

2014-01-01

Dissolved organic carbon (DOC) is a heterogeneous mixture of compounds that makes up a large fraction of the organic matter transported in streams. It plays a significant role in many ecosystems. Riverine DOC links organic carbon cycles of continental and oceanic ecosystems. It is a significant trophic resource in stream food webs. DOC imparts color to lakes,...

Fractionation for further conversion: from raw corn stover to lactic acid

OpenAIRE

Ting He; Zhicheng Jiang; Ping Wu; Jian Yi; Jianmei Li; Changwei Hu

2016-01-01

Fractionation is considered to be one promising strategy to utilize raw biomass to its fullest and produce chemicals with high selectivity. Herein, ethanol/H2O (1/1, v/v) co-solvent with 0.050?M oxalic acid is used to simultaneously fractionate 88.0?wt% of hemicellulose and 89.2?wt% of lignin in corn stover, while cellulose is not obviously degraded. H2O dissolves hemicellulose, G unit and those with ?-O-4 linkage of lignin; whereas ethanol extracts G and S units as well as the skeleton with ...

Radiobiological basis of total body irradiation with different dose rate and fractionation: repair capacity of hemopoietic cells

International Nuclear Information System (INIS)

Song, C.W.; Kim, T.H.; Khan, F.M.; Kersey, J.H.; Levitt, S.H.

1981-01-01

Total body irradiation (TBI) followed by bone marrow transplantation is being used in the treatment of malignant or non-malignant hemopoietic disorders. It has been believed that the ability of hemopoietic cells to repair sublethal radiation damage is negligible. Therefore, several schools of investigators suggested that TBI in a single exposure at extremely low dose rate (5 rad/min) over several hours, or in several fractions in 2-3 days, should yield a higher therapeutic gain, as compared with a single exposure at a high dose rate (26 rad/min). We reviewed the existing data in the literature, in particular, the response of hemopoietic cells to fractionated doses of irradiation and found that the repair capacity of both malignant and non-malignant hemopoietic cells might be greater than has been thought. It is concluded that we should not underestimate the ability of hemopoietic cells to repair sublethal radiation damage in using TBI

Winter to spring variations of chromophoric dissolved organic matter in a temperate estuary (Po River, northern Adriatic Sea).

Science.gov (United States)

Berto, D; Giani, M; Savelli, F; Centanni, E; Ferrari, C R; Pavoni, B

2010-07-01

The light absorbing fraction of dissolved organic carbon (DOC), known as chromophoric dissolved organic matter (CDOM) showed wide seasonal variations in the temperate estuarine zone in front of the Po River mouth. DOC concentrations increased from winter through spring mainly as a seasonal response to increasing phytoplankton production and thermohaline stratification. The monthly dependence of the CDOM light absorption by salinity and chlorophyll a concentrations was explored. In 2003, neither DOC nor CDOM were linearly correlated with salinity, due to an exceptionally low Po river inflow. Though the CDOM absorbance coefficients showed a higher content of chromophoric dissolved organic matter in 2004 with respect to 2003, the spectroscopic features confirmed that the qualitative nature of CDOM was quite similar in both years. CDOM and DOC underwent a conservative mixing, only after relevant Po river freshets, and a change in optical features with an increase of the specific absorption coefficient was observed, suggesting a prevailing terrestrial origin of dissolved organic matter. Published by Elsevier Ltd.

Fractionation and characterization of particles simulating wear of total joint replacement (TJR) following ASTM standards.

Science.gov (United States)

Saha, Subrata; Musib, Mrinal

2011-01-01

Reactions of bone cells to orthopedic wear debris produced by the articulating motion of total joint replacements (TJRs) are largely responsible for the long-term failure of such replacements. Metal and polyethylene (PE) wear particles isolated from fluids from total joint simulators, as well as particles that are fabricated by other methods, are widely used to study such in vitro cellular response. Prior investigations have revealed that cellular response to wear debris depends on the size, shape, and dose of the particles. Hence, to have a better understanding of the wear-mediated osteolytic process it is important that these particles are well characterized and clinically relevant, both qualitatively, and quantitatively. In this study we have fractionated both ultra-high molecular weight polyethylene (UHMWPE) and Ti particles, into micron (1.0-10.0 μm), submicron (0.2-1.0 μm), and nanoparticle (0.01-0.2 μm) fractions, and characterized them based on the following size-shape descriptors as put forth in ASTM F1877: i) equivalent circle diameter (ECD), ii) aspect ratio (AR), iii) elongation (E), iv) roundness (R), and v) form factor (FF). The mean (± SD) ECDs (in μm) for micron, submicron, and nanoparticles of UHMWPE were 1.652 ± 0.553, 0.270 ± 0.180, and 0.061 ± 0.035, respectively, and for Ti were 1.894 ± 0.667, 0.278 ± 0.180, and 0.055 ± 0.029, respectively. The values for other descriptors were similar (no statistically significant difference). The nanofraction particles were found to be more sphere-like (higher R and FF values, and lower E and AR values) as compared to larger particles. Future experiments will involve use of these well characterized particles for in vitro studies.

Determination of the Fate of Dissolved Organic Nitrogen in the Three Wastewater Treatment Plants, Jordan

Science.gov (United States)

Wedyan, Mohammed; Al Harahsheh, Ahmed; Qnaisb, Esam

2016-01-01

This research aimed to assess the composition of total dissolved nitrogen (TDN) species, particularly dissolved organic nitrogen (DON), over the traditional wastewater treatment operations in three biological nutrient removal (BNR) wastewater treatment plants (WWTPs) in Jordan. It had been found that the DON percentage was up to 30% of TDN within…

Anthropogenic inputs of dissolved organic matter in New York Harbor

Science.gov (United States)

Gardner, G. B.; Chen, R. F.; Olavasen, J.; Peri, F.

2016-02-01

The Hudson River flows into the Atlantic Ocean through a highly urbanized region which includes New York City to the east and Newark, New Jersey to the west. As a result, the export of Dissolved Organic Carbon (DOC) from the Hudson to the Atlantic Ocean includes a significant anthropogenic component. A series of high resolution studies of the DOC dynamics of this system were conducted between 2003 and 2010. These included both the Hudson and adjacent large waterways (East River, Newark Bay, Kill Van Kull and Arthur Kill) using coastal research vessels and smaller tributaries (Hackensack, Pasaic and Raritan rivers) using a 25' boat. In both cases measurements were made using towed instrument packages which could be cycled from near surface to near bottom depths with horizontal resolution of approximately 20 to 200 meters depending on depth and deployment strategy. Sensors on the instrument packages included a CTD to provide depth and salinity information and a chromophoric dissolved organic matter(CDOM) fluorometer to measure the fluorescent fraction of the DOC. Discrete samples allowed calibration of the fluorometer and the CDOM data to be related to DOC. The combined data set from these cruises identified multiple scales of source and transport processes for DOC within the Hudson River/New York Harbor region. The Hudson carries a substantial amount of natural DOC from its 230 km inland stretch. Additional sources exist in fringing salt marshes adjacent to the Hackensack and Raritan rivers. However the lower Hudson/New Harbor region receives a large input of DOC from multiple publically owned treatment works (POTW) discharges. The high resolution surveys allowed us to elucidate the distribution of these sources and the manner in which they are rapidly mixed to create the total export. We estimate that anthropogenic sources account for up to 2.5 times the DOC flux contributed by natural processes.

A novel technology coupling extraction and foam fractionation for separating the total saponins from Achyranthes bidentata.

Science.gov (United States)

Ding, Linlin; Wang, Yanji; Wu, Zhaoliang; Liu, Wei; Li, Rui; Wang, Yanyan

2016-10-02

A novel technology coupling extraction and foam fractionation was developed for separating the total saponins from Achyranthes bidentata. In the developed technology, the powder of A. bidentata was loaded in a nylon filter cloth pocket with bore diameter of 180 µm. The pocket was fixed in the bulk liquid phase for continuously releasing saponins. Under the optimal conditions, the concentration and the extraction rate of the total saponins in the foamate by the developed technology were 73.5% and 416.2% higher than those by the traditional technology, respectively. The foamates obtained by the traditional technology and the developed technology were analyzed by ultraperformance liquid chromatography-mass spectrometry to determine their ingredients, and the results appeared that the developed technology exhibited a better performance for separating saponins than the traditional technology. The study is expected to develop a novel technology for cost effectively separating plant-derived materials with surface activity.

Cation-induced coagulation of aquatic plant-derived dissolved organic matter: Investigation by EEM-PARAFAC and FT-IR spectroscopy

Science.gov (United States)

Interaction and coagulation of plant-derived dissolved organic matter (DOM) by metal cations are important biogeochemical processes of organic matter in lake systems. Thus, coagulation and fractionation of plant-derived DOM by di- and tri-valent Ca, Al, and Fe ions were investigated. Metal ion-induc...

The Distribution between the Dissolved and the Particulate Forms of 49 Metals across the Tigris River, Baghdad, Iraq

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Samera Hussein Hamad

2012-01-01

Full Text Available The distribution of dissolved and particulate forms of 49 elements was investigated along transect of the Tigris River (one of the major rivers of the world within Baghdad city and in its major tributary (Diyala River from 11 to 28 July 2011. SF-ICP-MS was used to measure total and filterable elements at 17 locations along the Tigris River transect, two samples from the Diyala River, and in one sample from the confluence of the two rivers. The calculated particulate forms were used to determine the particle-partition coefficients of the metals. No major changes in the elements concentrations down the river transect. Dissolved phases dominated the physical speciation of many metals (e.g., As, Mo, and Pt in the Tigris River, while Al, Fe, Pb, Th, and Ti were exhibiting high particulate fractions, with a trend of particle partition coefficients of [Ti(40 > Th(35 > Fe(15 > Al(13 > Pb(4.5] * 106 L/kg. Particulate forms of all metals exhibited high concentrations in the Diyala River, though the partition coefficients were low due to high TSS (~270 mg/L. A comparison of Tigris with the major rivers of the world showed that Tigris quality in Baghdad is comparable to Seine River quality in Paris.

Fractionation for further conversion: from raw corn stover to lactic acid

Science.gov (United States)

He, Ting; Jiang, Zhicheng; Wu, Ping; Yi, Jian; Li, Jianmei; Hu, Changwei

2016-12-01

Fractionation is considered to be one promising strategy to utilize raw biomass to its fullest and produce chemicals with high selectivity. Herein, ethanol/H2O (1/1, v/v) co-solvent with 0.050 M oxalic acid is used to simultaneously fractionate 88.0 wt% of hemicellulose and 89.2 wt% of lignin in corn stover, while cellulose is not obviously degraded. H2O dissolves hemicellulose, G unit and those with β-O-4 linkage of lignin; whereas ethanol extracts G and S units as well as the skeleton with β-5 and β-β linkages of lignin. Oxalic acid effectively catalyzes the hydrolysis of hemicellulose and breaks the intermolecular linkages between hemicellulose and lignin, therefore further promotes the release of lignin. The dissolved hemicelluloses derivatives are reprocessed to produce lactic acid obtaining a high yield of 79.6 wt% with 90% selectivity by the catalysis of MgO. The remained cellulose and recovered lignin can be used further as feedstock to produce chemicals.

Fractionation for further conversion: from raw corn stover to lactic acid

Science.gov (United States)

He, Ting; Jiang, Zhicheng; Wu, Ping; Yi, Jian; Li, Jianmei; Hu, Changwei

2016-01-01

Fractionation is considered to be one promising strategy to utilize raw biomass to its fullest and produce chemicals with high selectivity. Herein, ethanol/H2O (1/1, v/v) co-solvent with 0.050 M oxalic acid is used to simultaneously fractionate 88.0 wt% of hemicellulose and 89.2 wt% of lignin in corn stover, while cellulose is not obviously degraded. H2O dissolves hemicellulose, G unit and those with β-O-4 linkage of lignin; whereas ethanol extracts G and S units as well as the skeleton with β-5 and β-β linkages of lignin. Oxalic acid effectively catalyzes the hydrolysis of hemicellulose and breaks the intermolecular linkages between hemicellulose and lignin, therefore further promotes the release of lignin. The dissolved hemicelluloses derivatives are reprocessed to produce lactic acid obtaining a high yield of 79.6 wt% with 90% selectivity by the catalysis of MgO. The remained cellulose and recovered lignin can be used further as feedstock to produce chemicals. PMID:27917955

Dissolved oxygen and dietary phosphorus modulate utilization and effluent partitioning of phosphorus in rainbow trout (Oncorhynchus mykiss) aquaculture

International Nuclear Information System (INIS)

McDaniel, Nichole K.; Sugiura, Shozo H.; Kehler, Thomas; Fletcher, John W.; Coloso, Relicardo M.; Weis, Peddrick; Ferraris, Ronaldo P.

2005-01-01

Phosphorus (P) is the limiting nutrient in freshwater primary production, and excessive levels cause premature eutrophication. P levels in aquaculture effluents are now tightly regulated. Increasing our understanding of waste P partitioning into soluble, particulate, and settleable fractions is important in the management of effluent P. When water supply is limited, dissolved oxygen concentration (DO) decreases below the optimum levels. Therefore, we studied effects of DO (6 and 10 mg/L) and dietary P (0.7 and 1.0% P) on rainbow trout growth, P utilization, and effluent P partitioning. Biomass increased by 40% after 3 weeks. DO at 10 mg/L significantly increased fish growth and feed efficiency, and increased the amount of P in the soluble fraction of the effluent. Soluble effluent P was greater in fish fed 1.0% P. DO increases fish growth and modulates P partitioning in aquaculture effluent. - Dissolved oxygen concentration not only influences fish growth rate, but also affects dietary phosphorus utilization by fish in intensive aquaculture

Radiocarbon in dissolved organic matter in the central North Pacific Ocean

International Nuclear Information System (INIS)

Williams, P.M.; Druffel, E.R.M.

1987-01-01

The authors present the first detailed profile of radiocarbon measured in dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC) in the oligotrophic gyre of the central North Pacific. Δ 14 C of DOC ranged from -150 per mille (1,310 yr BP) in surface waters to -540 per mille (6,240 yr BP) at 5,710 m, 40 m off the bottom. The surprising similarity in the shapes of the profiles of Δ 14 C in the DOC and DIC pools suggest that similar processes are controlling the radiocarbon distribution in each of the two reservoirs and that bomb-produced radiocarbon has penetrated the DOC + DIC pools to a depth of ∼ 900 m. The depletion of the Δ 14 Csub(DOC) values by 300 per mille with respect to the Δ 14 Csub(DIC) values suggests that a certain fraction of the DOC is recycled within the ocean on longer time-scales than DIC. (author)

Qualitative changes of riverine dissolved organic matter at low salinities due to flocculation

Science.gov (United States)

Asmala, Eero; Bowers, David G.; Autio, Riitta; Kaartokallio, Hermanni; Thomas, David N.

2014-10-01

The flocculation of dissolved organic matter (DOM) was studied along transects through three boreal estuaries. Besides the bulk concentration parameters, a suite of DOM quality parameters were investigated, including colored DOM (CDOM), fluorescent DOM, and the molecular weight of DOM as well as associated dissolved iron concentrations. We observed significant deviations from conservative mixing at low salinities (DOC), UV absorption (a(CDOM254)), and humic-like fluorescence. The maximum deviation from conservative mixing for DOC concentration was -16%, at salinities between 1 and 2. An associated laboratory experiment was conducted where an artificial salinity gradient between 0 and 6 was created. The experiment confirmed the findings from the estuarine transects, since part of the DOC and dissolved iron pools were transformed to particulate fraction (>0.2 µm) and thereby removing them from the dissolved phase. We also measured flocculation of CDOM, especially in the UV region of the absorption spectrum. Protein-like fluorescence of DOM decreased, while humic-like fluorescence increased because of salt-induced flocculation. Additionally, there was a decrease in molecular weight of DOM. Consequently, the quantity and quality of the remaining DOM pool was significantly changed after influenced to flocculation. Based on these results, we constructed a mechanistic, two-component flocculation model. Our findings underline the importance of the coastal filter, where riverine organic matter is flocculated and exported to the sediments.

Experimental investigation and modeling of dissolved organic carbon removal by coagulation from seawater.

Science.gov (United States)

Jeong, Sanghyun; Sathasivan, Arumugam; Kastl, George; Shim, Wang Geun; Vigneswaran, Saravanamuthu

2014-01-01

Coagulation removes colloidal matters and dissolved organic carbon (DOC) which can cause irreversible membrane fouling. However, how DOC is removed by coagulant is not well-known. Jar test was used to study the removal of hydrophobic and hydrophilic DOC fractions at various doses (0.5-8.0 mg-Fe(+3) L(-1)) of ferric chloride (FeCl3) and pH (5.0-9.0). Natural organic matter (NOM) in seawater and treated seawater were fractionated by liquid chromatography-organic carbon detector (LC-OCD). Compared to surface water, the removal of DOC in seawater by coagulation was remarkably different. Majority of DOC could be easily removed with very low coagulant dose (fraction (HB) was better removed at high pH while hydrophilic fraction (HF) was better removed at low pH. A modified model of Kastl et al. (2004) which assumed that the removal occurred by adsorption of un-dissociated compounds onto ferric hydroxide was formulated and successfully validated against the jar test data. Copyright © 2013 Elsevier Ltd. All rights reserved.

Intestinal complications following accelerated fractionated X-irradiation

International Nuclear Information System (INIS)

Hauer-Jensen, M.; Poulakos, L.; Osborne, J.W.

1990-01-01

Due to paucity of suitable animal models, it has been difficult to study the development of long-term intestinal complications following fractionated irradiation. We recently developed a model which allows multiple radiation exposures of a short segment of rat ileum without the need for repeated surgery. In the present series, this model was used to study the influence of shortening the total treatment time (accelerated fractionation) on development of radiation enteropathy. Male rats were orchiectomized and a short segment of distal ileum was transposed to the scrotum. Starting 3 weeks after surgery, the scrotum containing the intestinal segment was X-irradiated with 20 fractions of 2.8 Gy (total dose 56 Gy). Two fractionation schedules were compared: one fraction per day (total treatment time 26 days) and 3 fractions per day (total treatment time 7 days). Actuarial survival curves were obtained, and the degree of radiation injury was assessed 2, 8 and 26 weeks after the last radiation exposure using a semiquantitative histopathologic scoring system. There was no mortality from acute radiation injury in either treatment group. All animals of the 1-fraction/day group survived the observation period (26 weeks). In the 3-fraction/day group, there was significant mortality due to intestinal obstruction, and cumulative mortality at 26 weeks was 100%. Radiation injury, as assessed by the histopathologic scoring system, was also more pronounced in this group than in the 1-fraction/day group. We conclude that shortening the total treatment time significantly increases the severity of late intestinal complications. Our data are suggestive of an association between acute mucosal damage and chronic radiation injury of the small intestine. (orig.)

Warming and organic matter sources impact the proportion of dissolved to total activities in marine extracellular enzymatic rates

KAUST Repository

Baltar, Federico; Moran, Xose Anxelu G.; Lø nborg, Christian

2017-01-01

Extracellular enzymatic activities (EEAs) are the rate-limiting step in the degradation of organic matter. Extracellular enzymes can be found associated to cells or dissolved in the surrounding water. The proportion of cell-free EEA constitutes

The Role of Refractory Dissolved Organic Matter in Ocean Carbon Sequestration

DEFF Research Database (Denmark)

Jørgensen, Linda

The ocean assimilates a large amount of atmospheric CO2 and is potentially a buffer for climate change. A fraction of the assimilated CO2 is incorporated into algal biomass and further converted into refractory dissolved organic matter (DOM). Carbon bound in refractory DOM has the potential...... studies the prokaryotic production and degradation of oceanic refractory DOM and discusses the reasons for the persistent nature of this large DOM fraction. The first two papers investigate the microbial carbon pump, i.e. prokaryotic transfor-mation of organic carbon into refractory DOM. The results show...... DOM compounds in the ocean are rare—possibly too rare to sustain viable uptake and assimilation. Hence, the dilute concentration of individual compounds is a possible explanation for the apparent refractory nature of most DOM in the ocean. Understanding the mechanisms that control the quality...

Suitability of selected free-gas and dissolved-gas sampling containers for carbon isotopic analysis.

Science.gov (United States)

Eby, P; Gibson, J J; Yi, Y

2015-07-15

Storage trials were conducted for 2 to 3 months using a hydrocarbon and carbon dioxide gas mixture with known carbon isotopic composition to simulate typical hold times for gas samples prior to isotopic analysis. A range of containers (both pierced and unpierced) was periodically sampled to test for δ(13)C isotopic fractionation. Seventeen containers were tested for free-gas storage (20°C, 1 atm pressure) and 7 containers were tested for dissolved-gas storage, the latter prepared by bubbling free gas through tap water until saturated (20°C, 1 atm) and then preserved to avoid biological activity by acidifying to pH 2 with phosphoric acid and stored in the dark at 5°C. Samples were extracted using valves or by piercing septa, and then introduced into an isotope ratio mass spectrometer for compound-specific δ(13)C measurements. For free gas, stainless steel canisters and crimp-top glass serum bottles with butyl septa were most effective at preventing isotopic fractionation (pierced and unpierced), whereas silicone and PTFE-butyl septa allowed significant isotopic fractionation. FlexFoil and Tedlar bags were found to be effective only for storage of up to 1 month. For dissolved gas, crimp-top glass serum bottles with butyl septa were again effective, whereas silicone and PTFE-butyl were not. FlexFoil bags were reliable for up to 2 months. Our results suggest a range of preferred containers as well as several that did not perform very well for isotopic analysis. Overall, the results help establish better QA/QC procedures to avoid isotopic fractionation when storing environmental gas samples. Recommended containers for air transportation include steel canisters and glass serum bottles with butyl septa (pierced and unpierced). Copyright © 2015 John Wiley & Sons, Ltd.

Seasonal variations of total 234Th and dissolved 238U concentration activities in surface water of Bransfield Strait, Antarctica, from March to October 2011

International Nuclear Information System (INIS)

Lapa, Flavia V.; Oliveira, Joselene de; Costa, Alice M.R.; Braga, Elisabete S.

2013-01-01

In this study the naturally occurring radionuclides 234 Th and 238 U were used to investigate the magnitude of upper ocean particulate organic carbon export in Bransfield Strait, Southern Ocean. This region is the largest oceanic high-nitrate low-chlorophyll (HNLC) area in the world and is known to contribute to regulate of the atmospheric CO 2 via the biological pump. Due to its different geochemical behavior in seawater, the resulting U/Th disequilibria can be easily used to constrain the transport rates of particles and reaction processes between solution and particulate phases. Sampling occurred during the summer (March and November) 2011. Total 234 Th activities in surface seawater samples ranged from 1.3 to 3.7 dpm L -1 (station EB 011) during March/11 campaign, while in October/11 total 234 Th activity concentrations varied from 1.4 to 2.9 dpm L -1 . Highest total 234 Th activities were found late in the austral summer season. Activity concentrations of dissolved 238 U in surface seawater varied from 2.1 to 2.4 dpm L -1 . Taking into account all sampling stations established in March and October/11 the relative variability of total 234 Th distribution was 22%. (author)

Impact of radiation technique, radiation fraction dose, and total cisplatin dose on hearing. Retrospective analysis of 29 medulloblastoma patients

International Nuclear Information System (INIS)

Scobioala, Sergiu; Kittel, Christopher; Ebrahimi, Fatemeh; Wolters, Heidi; Eich, Hans Theodor; Parfitt, Ross; Matulat, Peter; Am Zehnhoff-Dinnesen, Antoinette

2017-01-01

To analyze the incidence and degree of sensorineural hearing loss (SNHL) resulting from different radiation techniques, fractionation dose, mean cochlear radiation dose (D mean ), and total cisplatin dose. In all, 29 children with medulloblastoma (58 ears) with subclinical pretreatment hearing thresholds participated. Radiotherapy (RT) and cisplatin had been applied sequentially according to the HIT MED Guidance. Audiological outcomes up to the latest follow-up (median 2.6 years) were compared. Bilateral high-frequency SNHL was observed in 26 patients (90%). No significant differences were found in mean hearing threshold between left and right ears at any frequency. A significantly better audiological outcome (p < 0.05) was found after tomotherapy at the 6 kHz bone-conduction threshold (BCT) and left-sided 8 kHz air-conduction threshold (ACT) than after a combined radiotherapy technique (CT). Fraction dose was not found to have any impact on the incidence, degree, and time-to-onset of SNHL. Patients treated with CT had a greater risk of SNHL at high frequencies than tomotherapy patients even though D mean was similar. Increase in severity of SNHL was seen when the total cisplatin dose reached above 210 mg/m 2 , with the highest abnormal level found 8-12 months after RT regardless of radiation technique or fraction dose. The cochlear radiation dose should be kept as low as possible in patients who receive simultaneous cisplatin-based chemotherapy. The risk of clinically relevant HL was shown when D mean exceeds 45 Gy independent of radiation technique or radiation regime. Cisplatin ototoxicity was shown to have a dose-dependent effect on bilateral SNHL, which was more pronounced in higher frequencies. (orig.) [de

Tracing the long-term microbial production of recalcitrant fluorescent dissolved organic matter in seawater

DEFF Research Database (Denmark)

Jørgensen, Linda; Stedmon, Colin A.; Granskog, Mats A.

2014-01-01

The majority of dissolved organic matter (DOM) in the ocean is resistant to microbial degradation, yet its formation remains poorly understood. The fluorescent fraction of DOM can be used to trace the formation of recalcitrant DOM (RDOM). A long-term (> 1 year) experiment revealed 27–52% removal...... of dissolved organic carbon and a nonlinear increase in RDOM fluorescence associated with microbial turnover of semilabile DOM. This fluorescence was also produced using glucose as the only initial carbon source, suggesting that degradation of prokaryote remnants contributes to RDOM. Our results indicate...... that the formation of a fluorescent RDOM component depends on the bioavailability of the substrate: the less labile, the larger the production of fluorescent RDOM relative to organic carbon remineralized. The anticipated increase in microbial carbon demand due to ocean warming can potentially forcemicrobes...

Assessing the bioavailability of dissolved organic phosphorus in pasture and cultivated soils treated with different rates of nitrogen fertiliser

NARCIS (Netherlands)

McDowell, R.W.; Koopmans, G.F.

2006-01-01

A proportion of dissolved organic phosphorus (DOP) in soil leachates is readily available for uptake by aquatic organisms and, therefore, can represent a hazard to surface water quality. A study was conducted to characterise DOP in water extracts and soil P fractions of lysimeter soils (pasture

TOTAL AND FRACTIONAL CONTENTS OF PROTEINS IN BEAN SEEDS UNDER THE CONDITIONS OF VARIED FERTILISATION WITH MICROELEMENTS

Directory of Open Access Journals (Sweden)

Wojciech KOZERA

2013-03-01

Full Text Available Over 2003-2005 at the Experiment Station at Wierzchucinek at the University of Technology and Life Sciences in Bydgoszcz, there was performed a strict one-factor micro-plot experiment in split-splot design. The factor tested was a type of microelements [n=5: Cu, Zn, Mn, Mo, B]. The microelements were foliar sprayed in a chelated form, as the series of Symfonia fertilizers. The study aimed at comparing the effect of five agricultural-engineering basic microelements on the contents and protein composition of the seeds of Aura cultivar. The fertilization applied, boron and manganese in particular, showed an effect on the increase in the contents of total protein in bean seeds. It also modified the fractional composition of the bean seed protein. There was observed a clear increase in the fraction of albumins and globulins in seeds as a result of the microelements applied, except for boron. The fertilization with molybdenum, boron, copper and zinc reduced the content of glutelins, and the sum of glulelins and prolamines in the bean seeds.

Dissolved inorganic carbon, total alkalinity, pH, and other variables collected from surface and discrete observations using Niskin bottle, flow-through pump and other instruments from F.G. Walton Smith in the Gulf of Mexico (east coast of Florida near the Keys) from 2014-12-03 to 2014-12-04 (NCEI Accession 0154383)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains surface discrete measurement of dissolved inorganic carbon, total alkalinity, pH, dissolved oxygen and nutrients from a transect off...

Fractionation between inorganic and organic carbon during the Lomagundi (2.22 2.1 Ga) carbon isotope excursion

Science.gov (United States)

Bekker, A.; Holmden, C.; Beukes, N. J.; Kenig, F.; Eglinton, B.; Patterson, W. P.

2008-07-01

The Lomagundi (2.22-2.1 Ga) positive carbon isotope excursion in shallow-marine sedimentary carbonates has been associated with the rise in atmospheric oxygen, but subsequent studies have demonstrated that the carbon isotope excursion was preceded by the rise in atmospheric oxygen. The amount of oxygen released to the exosphere during the Lomagundi excursion is constrained by the average global fractionation between inorganic and organic carbon, which is poorly characterized. Because dissolved inorganic and organic carbon reservoirs were arguably larger in the Paleoproterozoic ocean, at a time of lower solar luminosity and lower ocean redox state, decoupling between these two variables might be expected. We determined carbon isotope values of carbonate and organic matter in carbonates and shales of the Silverton Formation, South Africa and in the correlative Sengoma Argillite Formation, near the border in Botswana. These units were deposited between 2.22 and 2.06 Ga along the margin of the Kaapvaal Craton in an open-marine deltaic setting and experienced lower greenschist facies metamorphism. The prodelta to offshore marine shales are overlain by a subtidal carbonate sequence. Carbonates exhibit elevated 13C values ranging from 8.3 to 11.2‰ vs. VPDB consistent with deposition during the Lomagundi positive excursion. The total organic carbon (TOC) contents range from 0.01 to 0.6% and δ13C values range from - 24.8 to - 13.9‰. Thus, the isotopic fractionation between organic and carbonate carbon was on average 30.3 ± 2.8‰ ( n = 32) in the shallow-marine environment. The underlying Sengoma shales have highly variable TOC contents (0.14 to 21.94%) and δ13C values (- 33.7 to - 20.8‰) with an average of - 27.0 ± 3.0‰ ( n = 50). Considering that the shales were also deposited during the Lomagundi excursion, and taking δ13C values of the overlying carbonates as representative of the δ13C value of dissolved inorganic carbon during shale deposition, a carbon

Fractionation of Pb and Cu in the fine fraction (landfill.

Science.gov (United States)

Kaczala, Fabio; Orupõld, Kaja; Augustsson, Anna; Burlakovs, Juris; Hogland, Marika; Bhatnagar, Amit; Hogland, William

2017-11-01

The fractionation of metals in the fine fraction (landfill was carried out to evaluate the metal (Pb and Cu) contents and their potential towards not only mobility but also possibilities of recovery/extraction. The fractionation followed the BCR (Community Bureau of Reference) sequential extraction, and the exchangeable (F1), reducible (F2), oxidizable (F3) and residual fractions were determined. The results showed that Pb was highly associated with the reducible (F2) and oxidizable (F3) fractions, suggesting the potential mobility of this metal mainly when in contact with oxygen, despite the low association with the exchangeable fraction (F1). Cu has also shown the potential for mobility when in contact with oxygen, since high associations with the oxidizable fraction (F3) were observed. On the other hand, the mobility of metals in excavated waste can be seen as beneficial considering the circular economy and recovery of such valuables back into the economy. To conclude, not only the total concentration of metals but also a better understanding of fractionation and in which form metals are bound is very important to bring information on how to manage the fine fraction from excavated waste both in terms of environmental impacts and also recovery of such valuables in the economy.

Water-Quality Constituents, Dissolved-Organic-Carbon Fractions, and Disinfection By-Product Formation in Water from Community Water-Supply Wells in New Jersey, 1998-99

Science.gov (United States)

Hopple, Jessica A.; Barringer, Julia L.; Koleis, Janece

2007-01-01

Water samples were collected from 20 community water-supply wells in New Jersey to assess the chemical quality of the water before and after chlorination, to characterize the types of organic carbon present, and to determine the disinfection by-product formation potential. Water from the selected wells previously had been shown to contain concentrations of dissolved organic carbon (DOC) that were greater than 0.2 mg/L. Of the selected wells, five are completed in unconfined (or semi-confined) glacial-sediment aquifers of the Piedmont and Highlands (New England) Physiographic Provinces, five are completed in unconfined bedrock aquifers of the Piedmont Physiographic Province, and ten are completed in unconsolidated sediments of the Coastal Plain Physiographic Province. Four of the ten wells in the Coastal Plain are completed in confined parts of the aquifers; the other six are in unconfined aquifers. One or more volatile organic compounds (VOCs) were detected in untreated water from all of the 16 wells in unconfined aquifers, some at concentrations greater than maximum contaminant levels. Those compounds detected included aliphatic compounds such as trichloroethylene and 1,1,1-trichloroethane, aromatic compounds such as benzene, the trihalomethane compound, chloroform, and the gasoline additive methyl tert-butyl ether (MTBE). Concentrations of sodium and chloride in water from one well in a bedrock aquifer and sulfate in water from another exceeded New Jersey secondary standards for drinking water. The source of the sulfate was geologic materials, but the sodium and chloride probably were derived from human inputs. DOC fractions were separated by passing water samples through XAD resin columns to determine hydrophobic fractions from hydrophilic fractions. Concentrations of hydrophobic acids were slightly lower than those of combined hydrophilic acids, neutral compounds, and low molecular weight compounds in most samples. Water samples from the 20 wells were adjusted

Antioxidant activity of cod (Gadus morhua) protein hydrolysates: Fractionation and characterisation of peptide fractions

DEFF Research Database (Denmark)

Farvin Habebullah, Sabeena; Andersen, Lisa Lystbæk; Otte, Jeanette

2016-01-01

This study aimed to characterise peptide fractions (>5 kDa, 3–5 kDa and fractions were dominated by Ala, Gly, Glu and Ser. The total amino acid composition had high proportions of Lys, Ala...... and Glu. The 3–5 kDa and fractions were further fractionated by size exclusion chromatography. All sub-fractions showed high Fe2+ chelating activity. The DPPH radical-scavenging activity of the 3–5 kDa fraction was exerted mainly by one sub-fraction dominated by peptides with masses below 600 Da....... The DPPH radical-scavenging activity of the fraction was exerted by sub-fractions with low molecular weight. The highest reducing power was found in a sub-fraction containing peptides rich in Arg, Tyr and Phe. Both free amino acids and low molecular weight peptides thus seemed to contribute...

Effect of dairy wastewater on changes in COD fractions in technical-scale SBR type reactors.

Science.gov (United States)

Struk-Sokołowska, Joanna; Rodziewicz, Joanna; Mielcarek, Artur

2017-04-01

The annual global production of milk is approximately 630,000 million litres and the volume of generated dairy wastewater accounts for 3.2 m 3 ·m -3 product. Dairy wastewater is characterized by a high load of chemical oxygen demand (COD). In many wastewater plants dairy wastewater and municipal wastewater are co-treated. The effect of dairy wastewater contribution on COD fraction changes in municipal sewage which has been treated with a sequencing batch reactor (SBR) in three wastewater treatment plants in north-east Poland is presented. In these plants the real contribution of dairy wastewater was 10, 13 and 17%. In raw wastewater, S S fraction (readily biodegradable dissolved organic matter) was dominant and ranged from 38.3 to 62.6%. In the effluent, S S fraction was not noted, which is indicative of consumption by microorganisms. The presence of dairy wastewater in municipal sewage does not cause changes in the content of the X I fraction (insoluble fractions of non-biodegradable organic matter). SBR effluents were dominated by non-biodegradable dissolved organic matter S I , which from 57.7 to 61.7%. In raw wastewater S I ranged from 1.0 to 4.6%. X s fraction (slowly biodegradable non-soluble organic matter) in raw wastewater ranged from 24.6 to 45.5% while in treated wastewater it ranged from 28.6 to 30.8%. In the control object (fourth wastewater plant) which does not process dairy wastewater, the S S , S I , X s and X I fraction in inflow was 28.7, 2.4, 51.7 and 17.2% respectively. In the effluent the S S , S I , X s and X I fraction was below 0.1, 33.6, 50.0 and 16.4% respectively.

Influence of overall treatment time in a fractionated total lymphoid irradiation as an immunosuppressive therapy in allogeneic bone marrow transplantation in mice

International Nuclear Information System (INIS)

Waer, M.; Ang, K.K.; Vandeputte, M.; Van der Schueren, E.

1982-01-01

Three groups of C 57 /BL/Ka mice received total lymphoid irradiation (TLI) in a total dose of 34 Gy in three different fractionation schedules. The tolerance of all different schedules was excellent. No difference in the peripheral white blood cell and lymphocyte counts nor the degree of immunosuppression as measured by phytohaemaglutinin or concanavalin A induced blastogenesis and mixed lymphocyte reaction were observed at the end of the treatment and up to 200 days. When bone marrow transplantation was performed one day after the end of each schedule, chimerism without signs of graft versus host disease was induced in all the groups. However, from the results in a limited number of animals it seems that concentrated schedules were less effective for chimerism induction. It has been demonstrated that it is possible to reduce drastically the overall treatment time for TLI before bone marrow transplantation. Further investigations are necessary in order to determine the optimal time-dose-fractionation factors and the different perameters involved in the transplantation

Mobility of the dissolved organic matter through intact boom clay cores

International Nuclear Information System (INIS)

Put, M.J.; Dierckx, A.; Aertsens, M.; Canniere, P. de

1998-01-01

Performance assessment studies are expected to predict the enhancement of the migration of trivalent lanthanides and actinides due to their complexation with organic matter, which play a role as a transport agent [1]. Therefore, the mobility of the dissolved organic matter in the interstitial boom clay water is studied. For the first time, the mobile fraction present in the clay water is concentrated and labelled with a radioisotope to study the mobility of the organic matter in clay and the interaction of the mobile with the non-mobile. The isotopes tested as label are 125 I and 14 C. The 125 I label proved to be unstable and hence discarded. The labelled organic matter is then diluted for migration experiments on boom clay cores under anaerobic conditions. The influence of the molecular size on its mobility is studied by the separation of the labelled organic matter in different size fractions. (orig.)

[Distributions and influencing factors of total dissolved inorganic antimony in the coastal area of Zhejiang and Fujian].

Science.gov (United States)

Zhang, Xu-Zhou; Ren, Jing-Ling; Liu, Zong-Guang; Fan, Xiao-Peng; Liu, Cheng-Gang; Wu, Ying

2014-02-01

Antimony has been ubiquitously present in the aquatic environment as a toxic and rare metalloid element. The contamination of antimony and its compounds in the environment is increasingly severe, so it has been received extensive attention by the international scientific community. The cruise was carried out in the coastal area of Zhejiang and Fujian provinces in the East China Sea (ECS) in May 2008. The concentrations of total dissolved inorganic antimony (TDISb) were measured by Hydride Generation-Atomic Fluorescence (HG-AFS). The concentration ranges of TDISb in the surface and bottom layer were 0.68-5.64 nmol x L(-1) and 0.71-5.25 nmol x L(-1) with averages of 2.25 and 1.79 nmol x L(-1), respectively. The concentration of TDISb in the study area was lower than the environmental quality standards for surface water of China and drinking water standards of World Health Organization (about 41.08 nmol x L(-1)), indicating that it remained at the pristine level. The concentration of TDISb decreased gradually from the coastal area to the central ECS shelf with higher concentration in the surface layer than the bottom. Water mass mixing, adsorption/desorption behavior on the surface of the suspended particulate matters (SPM) and biological activities were the main influence factors of TDISb biogeochemistry in the study area.

Combined effects of hydrographic structure and iron and copper availability on the phytoplankton growth in Terra Nova Bay Polynya (Ross Sea, Antarctica)

Science.gov (United States)

Rivaro, Paola; Luisa Abelmoschi, Maria; Grotti, Marco; Ianni, Carmela; Magi, Emanuele; Margiotta, Francesca; Massolo, Serena; Saggiomo, Vincenzo

2012-04-01

Surface water (CLIMA) Project of the Programma Nazionale di Ricerca in Antartide activities. Dissolved oxygen, nutrients, phytoplankton pigments and concentration and complexation of dissolved trace metals were determined. Experimental data were elaborated by Principal Component Analysis (PCA). As a result of solar heating and freshwater inputs from melting sea-ice, the water column was strongly stratified with an Upper Mixed Layer 4-16 m deep. The integrated Chl a in the layer 0-100 m ranged from 60 mg m-2 to 235 mg m-2, with a mean value of 138 mg m-2. The pigment analysis showed that diatoms dominated the phytoplankton assemblage. Major nutrients were generally high, with the lowest concentration at the surface and they were never fully depleted. The Si:N drawdown ratio was close to the expected value of 1 for Fe-replete diatoms. We evaluated both the total and the labile dissolved fraction of Fe and Cu. The labile fraction was operationally defined by employing the chelating resin Chelex-100, which retains free and loosely bound trace metal species. The total dissolved Fe ranged from 0.48 to 3.02 nM, while the total dissolved Cu from 3.68 to 6.84 nM. The dissolved labile Fe ranged from below the detection limit (0.15 nM) to 1.22 nM, and the dissolved labile Cu from 0.31 to 1.59 nM, respectively. The labile fractions measured at 20 m were significantly lower than values in 40-100 m samples. As two stations were re-sampled 5 days later, we evaluated the short-term variability of the physical and biogeochemical properties. In particular, in a re-sampled station at 20 m, the total dissolved Fe increased and the total dissolved Cu decreased, while their labile fraction was relatively steady. As a result of the increase in total Fe, the percentage of the labile Fe decreased. An increase of the Si:N, Si:P and Si:FUCO ratios was measured also in the re-sampled station. On this basis, we speculated that a switch from a Fe-replete to a Fe-deplete condition was occurring.

Dissolving method for nuclear fuel oxide

International Nuclear Information System (INIS)

Tomiyasu, Hiroshi; Kataoka, Makoto; Asano, Yuichiro; Hasegawa, Shin-ichi; Takashima, Yoichi; Ikeda, Yasuhisa.

1996-01-01

In a method of dissolving oxides of nuclear fuels in an aqueous acid solution, the oxides of the nuclear fuels are dissolved in a state where an oxidizing agent other than the acid is present together in the aqueous acid solution. If chlorate ions (ClO 3 - ) are present together in the aqueous acid solution, the chlorate ions act as a strong oxidizing agent and dissolve nuclear fuels such as UO 2 by oxidation. In addition, a Ce compound which generates Ce(IV) by oxidation is added to the aqueous acid solution, and an ozone (O 3 ) gas is blown thereto to dissolve the oxides of nuclear fuels. Further, the oxides of nuclear fuels are oxidized in a state where ClO 2 is present together in the aqueous acid solution to dissolve the oxides of nuclear fuels. Since oxides of the nuclear fuels are dissolved in a state where the oxidizing agent is present together as described above, the oxides of nuclear fuels can be dissolved even at a room temperature, thereby enabling to use a material such as polytetrafluoroethylene and to dissolve the oxides of nuclear fuels at a reduced cost for dissolution. (T.M.)

Long-term renal toxicity in children following fractionated total-body irradiation (TBI) before allogeneic stem cell transplantation (SCT)

International Nuclear Information System (INIS)

Gerstein, Johanna; Meyer, Andreas; Fruehauf, Joerg; Karstens, Johann H.; Bremer, Michael; Sykora, Karl-Walter

2009-01-01

Purpose: to retrospectively assess the incidence and time course of renal dysfunction in children (≤ 16 years) following total-body irradiation (TBI) before allogeneic stem cell transplantation (SCT). Patients and methods: between 1986 and 2003, 92 children (median age, 11 years; range, 3-16 years) underwent TBI before allogeneic SCT. 43 of them had a minimum follow-up of 12 months (median, 51 months; range, 12-186 months) and were included into this analysis. Conditioning regimen included chemotherapy and fractionated TBI with 12 Gy (n = 26) or 11.1 Gy (n = 17). In one patient, renal dose was limited to 10 Gy by customized renal shielding due to known nephropathy prior to SCt. Renal dysfunction was defined as an increase of serum creatinine > 1.25 times the upper limit of age-dependent normal. Results: twelve children (28%) experienced an episode of renal dysfunction after a median of 2 months (range, 1-10 months) following SCT. In all but one patient renal dysfunction was transient and resolved after a median of 8 months (range, 3-16 months). One single patient developed persistent renal dysfunction with onset at 10 months after SCT. None of these patients required dialysis. The actuarial 3-year freedom from persistent renal toxicity for children surviving > 12 months after SCt was 97.3%. Conclusion: the incidence of persistent renal dysfunction after fractionated TBI with total doses ≤ 12 Gy was very low in this analysis. (orig.)

DETERMINATION OF THE FRACTION OF GIBBSITE AND BOEHMITE FORMS OF ALUMINUM IN TANK 51H SLUDGE

International Nuclear Information System (INIS)

Hay, M; Kofi Adu-Wusu, K; Daniel McCabe, D

2008-01-01

The Savannah River National Laboratory (SRNL) was tasked with developing a test to determine the fraction of the gibbsite and boehmite forms of aluminum in the sludge solids. Knowledge of the fractions of gibbsite and boehmite in the sludge contained in various waste tanks would facilitate better sludge mass reduction estimates and allow better planning/scheduling for sludge batch preparation. The composite sludge sample prepared for use in the test from several small samples remaining from the original 3-L sample appears to be representative of the original sample based on the characterization data. A Gibbsite/Boehmite Test was developed that uses 8 M NaOH and a temperature of 65 C to dissolve aluminum. The soluble aluminum concentration data collected during the test indicates that, for the three standards containing gibbsite, all of the gibbsite dissolved in approximately 2 hours. Under the test conditions boehmite dissolved at more than an order of magnitude more slowly than gibbsite. An estimate based on the soluble aluminum concentration from the sludge sample at two hours into the test indicates the sludge solids contain a form of aluminum that dissolves at a rate similar to the 100% Boehmite standard. Combined with the XRD data from the original 3-L sample, these results provide substantial evidence that the boehmite form of aluminum predominates in the sludge. A calculation from the results of the Gibbsite/Boehmite test indicates the sludge contains ∼3% gibbsite and ∼97% boehmite. The sludge waste in Tank 51H was recently treated under Low Temperature Aluminum Dissolution (LTAD) conditions and a substantial fraction of aluminum (i.e., sludge mass) was removed, avoiding production of over 100 glass canisters in Defense Waste Processing Facility (DWPF). Results of the Gibbsite/Boehmite test indicate that the aluminum in this sludge was in the form of the more difficult to dissolve boehmite form of aluminum. Since boehmite may be the dominant form of

Studies on proinsulin and proglucagon biosynthesis and conversion at the subcellular level: I. Fractionation procedure and characterization of the subcellular fractions

Science.gov (United States)

Noe, BD; Baste, CA; Bauer, GE

1977-01-01

Anglerfish islets were homogenized in 0.25 M sucrose and separated into seven separate subcellular fractions by differential and discontinuous density gradient centrifugation. The objective was to isolate microsomes and secretory granules in a highly purified state. The fractions were characterized by electron microscopy and chemical analyses. Each fraction was assayed for its content of protein, RNA, DNA, immunoreactive insulin (IRI), and immunoreactive glucagon (IRG). Ultrastructural examination showed that two of the seven subcellular fractions contain primarily mitochondria, and that two others consist almost exclusively of secretory granules. A fifth fraction contains rough and smooth microsomal vesicles. The remaining two fractions are the cell supernate and the nuclei and cell debris. The content of DNA and RNA in all fractions is consistent with the observed ultrastructure. More than 82 percent of the total cellular IRI and 89(percent) of the total cellular IRG are found in the fractions of secretory granules. The combined fractions of secretory granules and microsomes consistently yield >93 percent of the total IRG. These results indicate that the fractionation procedure employed yields fractions of microsomes and secretory granules that contain nearly all the immunoassayable insulin and glucagons found in whole islet tissue. These fractions are thus considered suitable for study of proinsulin and proglucagon biosynthesis and their metabolic conversion at the subcellular level. PMID:328517

Examining the role of dissolved organic nitrogen in stream ecosystems across biomes and Critical Zone gradients

Science.gov (United States)

Wymore, A.; Rodriguez-Cardona, B.; Coble, A. A.; Potter, J.; Lopez Lloreda, C.; Perez Rivera, K.; De Jesus Roman, A.; Bernal, S.; Martí Roca, E.; Kram, P.; Hruska, J.; Prokishkin, A. S.; McDowell, W. H.

2016-12-01

Watershed nitrogen exports are often dominated by dissolved organic nitrogen (DON); yet, little is known about the role ambient DON plays in ecosystems. As an organic nutrient, DON may serve as either an energy source or as a nutrient source. One hypothesized control on DON is nitrate (NO3-) availability. Here we examine the interaction of NO3- and DON in streams across temperate forests, tropical rainforests, and Mediterranean and taiga biomes. Experimental streams also drain contrasting Critical Zones which provide gradients of vegetation, soil type and lithology (e.g. volcaniclastic, granitic, ultramafic, Siberian Traps Flood Basalt) in which to explore how the architecture of the Critical Zone affects microbial biogeochemical reactions. Streams ranged in background dissolved organic carbon (DOC) concentration (1-50 mg C/L) and DOC: NO3- ratios (10-2000). We performed a series of ecosystem-scale NO3- additions in multiple streams within each environment and measured the change in DON concentration. Results demonstrate that there is considerable temporal and spatial variation across systems with DON both increasing and decreasing in response to NO3- addition. Ecologically this suggests that DON can serve as both a nutrient source and an energy source to aquatic microbial communities. In contrast, DOC concentrations rarely changed in response to NO3- additions suggesting that the N-rich fraction of the ambient dissolved organic matter pool is more bioreactive than the C-rich fraction. Contrasting responses of the DON and DOC pools indicate different mechanisms controlling their respective cycling. It is likely that DON plays a larger role in ecosystems than previously recognized.

Iodide-assisted total lead measurement and determination of different lead fractions in drinking water samples.

Science.gov (United States)

Zhang, Yuanyuan; Ng, Ding-Quan; Lin, Yi-Pin

2012-07-01

Lead and its compounds are toxic and can harm human health, especially the intelligence development in children. Accurate measurement of total lead present in drinking water is crucial in determining the extent of lead contamination and human exposure due to drinking water consumption. The USEPA method for total lead measurement (no. 200.8) is often used to analyze lead levels in drinking water. However, in the presence of high concentration of the tetravalent lead corrosion product PbO(2), the USEPA method was not able to fully recover particulate lead due to incomplete dissolution of PbO(2) particles during strong acid digestion. In this study, a new procedure that integrates membrane separation, iodometric PbO(2) measurement, strong acid digestion and ICP-MS measurement was proposed and evaluated for accurate total lead measurement and quantification of different lead fractions including soluble Pb(2+), particulate Pb(II) carbonate and PbO(2) in drinking water samples. The proposed procedure was evaluated using drinking water reconstituted with spiked Pb(2+), spiked particulate Pb(II) carbonate and in situ formed or spiked PbO(2). Recovery tests showed that the proposed procedure and the USEPA method can achieve 93-112% and 86-103% recoveries respectively for samples containing low PbO(2) concentrations (0.018-0.076 mg Pb per L). For samples containing higher concentrations of PbO(2) (0.089-1.316 mg Pb per L), the USEPA method failed to meet the recovery requirement for total lead (85-115%) while the proposed method can achieve satisfactory recoveries (91-111%) and differentiate the soluble Pb(2+), particulate Pb(II) carbonate and PbO(2).

Classification and Processing Optimization of Barley Milk Production Using NIR Spectroscopy, Particle Size, and Total Dissolved Solids Analysis

Directory of Open Access Journals (Sweden)

Jasenka Gajdoš Kljusurić

2015-01-01

Full Text Available Barley is a grain whose consumption has a significant nutritional benefit for human health as a very good source of dietary fibre, minerals, vitamins, and phenolic and phytic acids. Nowadays, it is more and more often used in the production of plant milk, which is used to replace cow milk in the diet by an increasing number of consumers. The aim of the study was to classify barley milk and determine the optimal processing conditions in barley milk production based on NIR spectra, particle size, and total dissolved solids analysis. Standard recipe for barley milk was used without added additives. Barley grain was ground and mixed in a blender for 15, 30, 45, and 60 seconds. The samples were filtered and particle size of the grains was determined by laser diffraction particle sizing. The plant milk was also analysed using near infrared spectroscopy (NIRS, in the range from 904 to 1699 nm. Furthermore, conductivity of each sample was determined and microphotographs were taken in order to identify the structure of fat globules and particles in the barley milk. NIR spectra, particle size distribution, and conductivity results all point to 45 seconds as the optimal blending time, since further blending results in the saturation of the samples.

Establishment of a paediatric age-related reference interval for the measurement of urinary total fractionated metanephrines.

LENUS (Irish Health Repository)

Griffin, Alison

2012-02-01

INTRODUCTION: Normetanephrine and metanephrine are intermediate metabolites of noradrenaline and adrenaline metabolism. To assess whether normetanephrine and metanephrine analysis may aid in the diagnosis of Neuroblastoma, a reference interval for these metabolites must first be established. AIM: The overall aim of this study was to establish a paediatric age-related reference interval for the measurement of total fractionated metanephrines. METHODS: A total of 267 urine samples were analysed following acid hydrolysis. This releases the metanephrines from their sulphate-bound metabolites. The samples were analysed using reverse phase high-performance liquid chromatography with electro-chemical detection on a Gilson automated sequential trace enrichment of dialysate sample system. RESULTS: Data were analysed using Minitab Release version 14. Outliers were removed using the Dixon\\/Reed one-third rule. Partitioning of the age groups was achieved using Harris and Boyd\\'s standard normal deviate test. Non-parametric analysis of the data was performed, followed by the establishment of the 2.5th and the 97.5th reference limits. CONCLUSIONS: The established reference intervals are described in Table 2.

Fractionated irradiation and haematopoiesis. Pt. 3

International Nuclear Information System (INIS)

Ninkov, V.; Karanovic, D.; Savovski, K.

1982-01-01

The effect of total single fractionated irradiation with short time interval on heamatopoietic regeneration of the bone marrow and spleen was investigated. Also, the importance of first dose, when dose of 600 R was divided in two unequal fractions with time interval of 300 s was studied. The investigation was performed on 25 day old rats. The dose of 600 R (X-rays) was divided on: 500 + 100, 400 + 200, 300 + 300, 200 + 400 or 100 + 500 R with time interval of 150, 300 or 600 s. Ten days after irradiation the changes in blood, bone marrow and spleen were observed. After unequal fractionated dose with interval of 600 s slight effect was found. The results after intervals of 600 s and 300 s were significant, when the total dose was divided in two equal doses. The first dose has no promoting role in haematopoietic regeneration when total dose was unequally fractionated. (orig.) [de

The molecular mechanism of Mo isotope fractionation during adsorption to birnessite

Science.gov (United States)

Wasylenki, L.E.; Weeks, C.L.; Bargar, J.R.; Spiro, T.G.; Hein, J.R.; Anbar, A.D.

2011-01-01

Fractionation of Mo isotopes during adsorption to manganese oxides is a primary control on the global ocean Mo isotope budget. Previous attempts to explain what drives the surprisingly large isotope effect ??97/95Modissolved-??97/95Moadsorbed=1.8??? have not successfully resolved the fractionation mechanism. New evidence from extended X-ray absorption fine structure analysis and density functional theory suggests that Mo forms a polymolybdate complex on the surfaces of experimental and natural samples. Mo in this polynuclear structure is in distorted octahedral coordination, while Mo remaining in solution is predominantly in tetrahedral coordination as MoO42- Our results indicate that the difference in coordination environment between dissolved Mo and adsorbed Mo is the cause of isotope fractionation. The molecular mechanism of metal isotope fractionation in this system should enable us to explain and possibly predict metal isotope effects in other systems where transition metals adsorb to mineral surfaces. ?? 2011 Elsevier Ltd.

Nitrogen fixation in the activated sludge treatment of thermomechanical pulping wastewater: effect of dissolved oxygen.

Science.gov (United States)

Slade, A H; Anderson, S M; Evans, B G

2003-01-01

N-ViroTech, a novel technology which selects for nitrogen-fixing bacteria as the bacteria primarily responsible for carbon removal, has been developed to treat nutrient limited wastewaters to a high quality without the addition of nitrogen, and only minimal addition of phosphorus. Selection of the operating dissolved oxygen level to maximise nitrogen fixation forms a key component of the technology. Pilot scale activated sludge treatment of a thermomechanical pulping wastewater was carried out in nitrogen-fixing mode over a 15 month period. The effect of dissolved oxygen was studied at three levels: 14% (Phase 1), 5% (Phase 2) and 30% (Phase 3). The plant was operated at an organic loading of 0.7-1.1 kg BOD5/m3/d, a solids retention time of approximately 10 d, a hydraulic retention time of 1.4 d and a F:M ratio of 0.17-0.23 mg BOD5/mg VSS/d. Treatment performance was very stable over the three dissolved oxygen operating levels. The plant achieved 94-96% BOD removal, 82-87% total COD removal, 79-87% soluble COD removal, and >99% total extractives removal. The lowest organic carbon removals were observed during operation at 30% DO but were more likely to be due to phosphorus limitation than operation at high dissolved oxygen, as there was a significant decrease in phosphorus entering the plant during Phase 3. Discharge of dissolved nitrogen, ammonium and oxidised nitrogen were consistently low (1.1-1.6 mg/L DKN, 0.1-0.2 mg/L NH4+-N and 0.0 mg/L oxidised nitrogen). Discharge of dissolved phosphorus was 2.8 mg/L, 0.1 mg/L and 0.6 mg/L DRP in Phases 1, 2 and 3 respectively. It was postulated that a population of polyphosphate accumulating bacteria developed during Phase 1. Operation at low dissolved oxygen during Phase 2 appeared to promote biological phosphorus uptake which may have been affected by raising the dissolved oxygen to 30% in Phase 3. Total nitrogen and phosphorus discharge was dependent on efficient secondary clarification, and improved over the course of

Acid-base and copper-binding properties of three organic matter fractions isolated from a forest floor soil solution

Science.gov (United States)

van Schaik, Joris W. J.; Kleja, Dan B.; Gustafsson, Jon Petter

2010-02-01

Vast amounts of knowledge about the proton- and metal-binding properties of dissolved organic matter (DOM) in natural waters have been obtained in studies on isolated humic and fulvic (hydrophobic) acids. Although macromolecular hydrophilic acids normally make up about one-third of DOM, their proton- and metal-binding properties are poorly known. Here, we investigated the acid-base and Cu-binding properties of the hydrophobic (fulvic) acid fraction and two hydrophilic fractions isolated from a soil solution. Proton titrations revealed a higher total charge for the hydrophilic acid fractions than for the hydrophobic acid fraction. The most hydrophilic fraction appeared to be dominated by weak acid sites, as evidenced by increased slope of the curve of surface charge versus pH at pH values above 6. The titration curves were poorly predicted by both Stockholm Humic Model (SHM) and NICA-Donnan model calculations using generic parameter values, but could be modelled accurately after optimisation of the proton-binding parameters (pH ⩽ 9). Cu-binding isotherms for the three fractions were determined at pH values of 4, 6 and 9. With the optimised proton-binding parameters, the SHM model predictions for Cu binding improved, whereas the NICA-Donnan predictions deteriorated. After optimisation of Cu-binding parameters, both models described the experimental data satisfactorily. Iron(III) and aluminium competed strongly with Cu for binding sites at both pH 4 and pH 6. The SHM model predicted this competition reasonably well, but the NICA-Donnan model underestimated the effects significantly at pH 6. Overall, the Cu-binding behaviour of the two hydrophilic acid fractions was very similar to that of the hydrophobic acid fraction, despite the differences observed in proton-binding characteristics. These results show that for modelling purposes, it is essential to include the hydrophilic acid fraction in the pool of 'active' humic substances.

A pilot study to evaluate the cost-effectiveness of ondansetron and granisetron in fractionated total body irradiation

Energy Technology Data Exchange (ETDEWEB)

Gibbs, S.J.; Cassoni, A.M. [Middlesex Hospital, London (United Kingdom)

1996-11-01

The duration of the antiemetic effect of granisetron was examined in a pilot study of patients (n = 26) undergoing a standard emetogenic stimulus in the form of total body irradiation fractionated over 3-4 days, in a randomized comparison with twice-daily ondansetron. A single intravenous dose of granisetron at the onset of therapy was effective over the entire follow-up period in 50% (6/12) of patients, compared with 77% (10/13) prescribed twice-daily oral ondansetron for 3 or 4 days. The response rate within the first 24 hours from the start of irradiation was 67% (8/12) for granisetron and 77% (10/13) for ondansetron. Granisetron and ondansetron was therefore of similar efficacy within the first 24-hour period, but granisetron was less efficaceous more than 24 hours after the onset of therapy. Patients who required a second dose of granisetron did so at intervals of 12, 42, 47 and 48 hours following the first fraction of radiotherapy. The cost per patient in this study was 48 for granisetron and {sub 1}54 for ondanestron, but the dose scheduling we used cannot be recommended in view of the lower effectiveness of granisetron. (author).

A pilot study to evaluate the cost-effectiveness of ondansetron and granisetron in fractionated total body irradiation

International Nuclear Information System (INIS)

Gibbs, S.J.; Cassoni, A.M.

1996-01-01

The duration of the antiemetic effect of granisetron was examined in a pilot study of patients (n = 26) undergoing a standard emetogenic stimulus in the form of total body irradiation fractionated over 3-4 days, in a randomized comparison with twice-daily ondansetron. A single intravenous dose of granisetron at the onset of therapy was effective over the entire follow-up period in 50% (6/12) of patients, compared with 77% (10/13) prescribed twice-daily oral ondansetron for 3 or 4 days. The response rate within the first 24 hours from the start of irradiation was 67% (8/12) for granisetron and 77% (10/13) for ondansetron. Granisetron and ondansetron was therefore of similar efficacy within the first 24-hour period, but granisetron was less efficaceous more than 24 hours after the onset of therapy. Patients who required a second dose of granisetron did so at intervals of 12, 42, 47 and 48 hours following the first fraction of radiotherapy. The cost per patient in this study was 48 for granisetron and 1 54 for ondanestron, but the dose scheduling we used cannot be recommended in view of the lower effectiveness of granisetron. (author)

Effect of weight fraction of different constituent elements on the total ...

Indian Academy of Sciences (India)

The mass attenuation coefficients, µm, of biological materials have been ... increasing percentage of constituent elements in high energy region up to 10 MeV. ... Muscle. 72.89. Figure 1. Plot of µm (cm2/g) vs. hydrogen weight fraction at some ...

Annual dissolved nitrite plus nitrate and total phosphorous loads for the Susquehanna, St. Lawrence, Mississippi-Atchafalaya, and Columbia River basins, 1968-2004

Science.gov (United States)

Aulenbach, Brent T.

2006-01-01

Annual stream-water loads were calculated near the outlet of four of the larger river basins (Susquehanna, St. Lawrence, Mississippi-Atchafalaya, and Columbia) in the United States for dissolved nitrite plus nitrate (NO2 + NO3) and total phosphorus using LOADEST load estimation software. Loads were estimated for the period 1968-2004; although loads estimated for individual river basins and chemical constituent combinations typically were for shorter time periods due to limitations in data availability. Stream discharge and water-quality data for load estimates were obtained from the U.S. Geological Survey (USGS) with additional stream discharge data for the Mississippi-Atchafalaya River Basin from the U.S. Army Corps of Engineers. The loads were estimated to support national assessments of changes in stream nutrient loads that are periodically conducted by Federal agencies (for example, U.S. Environmental Protection Agency) and other water- and land-resource organizations. Data, methods, and results of load estimates are summarized herein; including World Wide Web links to electronic ASCII text files containing the raw data. The load estimates are compared to dissolved NO2 + NO3 loads for three of the large river basins from 1971 to 1998 that the USGS provided during 2001 to The H. John Heinz III Center for Science, Economics and the Environment (The Heinz Center) for a report The Heinz Center published during 2002. Differences in the load estimates are the result of using the most up-to-date monitoring data since the 2001 analysis, differences in how concentrations less than the reporting limit were handled by the load estimation models, and some errors and exclusions in the 2001 analysis datasets (which resulted in some inaccurate load estimates).

Chemical characteristics of dissolved organic matter (DOM) in relation to heavy metal concentrations in soil water from boreal peatlands after clear-cut harvesting

Science.gov (United States)

Kiikkilä, O.; Nieminen, T.; Starr, M.; Ukonmaanaho, L.

2012-04-01

Boreal peatlands form an important terrestrial carbon reserve and are a major source of dissolved organic matter (DOM) to surface waters, particularly when disturbed through forestry practices such as draining or timber harvesting. Heavy metals show a strong affinity to organic matter and so, along with DOM, heavy metals can be mobilized and transported from the soil to surface waters and sediments where they may become toxic to aquatic organisms and pass up the food chain. The complexation of heavy metals with DOM can be expected to be related and determined by the chemical characteristics of DOM and oxidation/reducing conditions in the peat. We extracted interstitial water from peat samples and determined the concentrations of dissolved organic carbon (DOC), dissolved organic nitrogen (DON) and Al, Cu, Zn and Fe in various fractions of DOM isolated by adsorption properties (XAD-8 fractionation) and molecular-weight (ultrafiltration). The peat samples were taken from 0-30 and 30-50 cm depth in drained peatland catchments two years after whole-tree or stem-only clear-cut harvesting (Scots pine or Norway spruce) had been carried out. The samples from the upper layer had been subject to alternating saturation/aeration conditions while the deeper layer had been continuously under the water table. The fractionation of DOC and DON according to both adsorption properties and molecular-weight fractions clearly differed between the upper and lower peat layers. While the hydrophobic acid fraction contained proportionally more DOC and DON than the hydrophilic acid fraction in the upper peat layer the results were vice versa in the lower peat layer. High-molecular-weight compounds (> 100 kDa) were proportionally more abundant in the upper and low-molecular-weight compounds (< 1 kDa) in the lower peat layer. These differences are assumed to reflect differences in the aerobic/ anaerobic conditions and degree of decomposition between the two layers. The concentrations of Zn, Al

Earthworms change the quantity and composition of dissolved organic carbon and reduce greenhouse gas emissions during composting.

Science.gov (United States)

Nigussie, Abebe; Bruun, Sander; de Neergaard, Andreas; Kuyper, Thomas W

2017-04-01

Dissolved organic carbon (DOC) has recently been proposed as an indicator of compost stability. We assessed the earthworms' effect on DOC content and composition during composting, and linked compost stability to greenhouse gas emissions and feeding ratio. Earthworms reduced total DOC content, indicating larger stability of vermicompost than of thermophilic compost. The concentrations of humic acid and fulvic acid were reduced by earthworms, whereas there was no significant effect on hydrophobic neutrals and hydrophilics. The humic acid fraction was depleted more quickly than the other compounds, indicating humic acid degradation during composting. The optimum feeding ratio decreased DOC content compared to the high feeding ratio. The lowest N 2 O emissions were also observed at the optimum feeding ratio. Our study confirmed the use of DOC content and composition as an indicator of compost stability and suggested that feeding ratio should be considered when assessing the earthworms' effect on stabilisation and greenhouse gas emissions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Dissolved inorganic carbon, total alkalinity, pH, nutrients, and other variables collected from profile and discrete observations using Niskin bottle and other instruments from NOAA Ship Gordon Gunter on the northeastern U.S. continental shelf, Gulf of Maine, coastal waters of Canada, Greenland and Iceland from 2015-10-13 to 2015-10-24 (NCEI Accession 0157023)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains profile discrete measurements of dissolved inorganic carbon, total alkalinity, pH, dissolved oxygen, and nutrients in the North...

Effect of wildfires on physicochemical changes of watershed dissolved organic matter.

Science.gov (United States)

Revchuk, Alex D; Suffet, I H

2014-04-01

Physicochemical characterization of dissolved organic carbon (DOC) provides essential data to describe watershed characteristics after drastic changes caused by wildfires. Post-fire watershed behavior is important for water source selection, management, and drinking water treatment optimization. Using ash and other burned vegetation fragments, a leaching procedure was implemented to describe physicochemical changes to watershed DOC caused by wildfires. Samples were collected after the 2007 and 2009 wildfires near Santa Barbara, California. Substantial differences in size distribution (measured by ultrafiltration), polarity (measured by polarity rapid assessment method), and the origin of leached DOC (measured by fluorescence) were observed between burned and unburned sites. Recently burned ash had 10 times the DOC leaching potential, and was dominated by large size fragments, compared to weathered 2-year-old ash. Charged DOC fractions were found to positively correlate with DOC size, whereas hydrophobic and hydrophilic DOC fractions were not. Proteins were only observed in recently burned ash and were indicative of recent post-fire biological activity.

Methodology to quantify the role of the factors controlling the variation of rivers' total dissolved solids in Jiu Catchment (Romania)

Science.gov (United States)

Adina Morosanu, Gabriela; Zaharia, Liliana; Ioana-Toroimac, Gabriela; Belleudy, Philippe

2017-04-01

The total dissolved solids (TDS) is a river water quality parameter reflecting its concentration in solute ions. It is sensitive to many physical and anthropogenic features of the watershed. In this context, the objective of this work is to analyze the spatial variation of the TDS and to identify the role of the main controlling factors (e.g. geology, soils, land use) in Jiu River and some of its main tributaries, by using a methodology based on GIS and multivariate analysis. The Jiu watershed (10,000 kmp) is located in south-western Romania and it has a high diversity of physical and anthropogenic features influencing the water flow and its quality. The study is based on TDS measurements performed in August, 2016, during low flow conditions in the Jiu River and its tributaries. To measure in situ the TDS (ppm), an EC/TDS/Temperature Hand-held Tester was used in the 12 measuring points on Jiu River and in another 7 points on some of its tributaries. Across the hydrographic basin, the recorded TDS values ranged from 31 ppm to 607 ppm, while in the case of Jiu River, the TDS varied between 38 ppm at Lonea station (upper Jiu River) and 314 ppm at Išalniča (in the lower course). For each catchment corresponding to the sampling points, the influence of some contiguous features was defined on the basis of the lithology (marls, limestones, erodible bedrocks) and soils (clay textures), as well as the land cover/use influencing the solubility and solid content. This assessment was carried out in GIS through a set of spatial statistics analysis by calculating the percentages of the catchment coverage area for each determinant. In order to identify the contributions of different catchment features on the TDS variability, principal components analysis (PCA) was then applied. The results revealed the major role of the marls and clayey soils in the increase of TDS (on the Amaradia and Gilort rivers and some sections in the middle course of the Jiu River). In contrast

Technical Note: Precise quantitative measurements of total dissolved inorganic carbon from small amounts of seawater using a gas chromatographic system

Directory of Open Access Journals (Sweden)

T. Hansen

2013-10-01

Full Text Available Total dissolved inorganic carbon (CT is one of the most frequently measured parameters used to calculate the partial pressure of carbon dioxide in seawater. Its determination has become increasingly important because of the rising interest in the biological effects of ocean acidification. Coulometric and infrared detection methods are currently favored in order to precisely quantify CT. These methods however are not sufficiently validated for CT measurements of biological experiments manipulating seawater carbonate chemistry with an extended CT measurement range (~1250–2400 μmol kg–1 compared to natural open ocean seawater (~1950–2200 μmol kg−1. The requirement of total sample amounts between 0.1–1 L seawater in the coulometric- and infrared detection methods potentially exclude their use for experiments working with much smaller volumes. Additionally, precise CT analytics become difficult with high amounts of biomass (e.g., phytoplankton cultures or even impossible in the presence of planktonic calcifiers without sample pre-filtration. Filtration however, can alter CT concentration through gas exchange induced by high pressure. Addressing these problems, we present precise quantification of CT using a small, basic and inexpensive gas chromatograph as a CT analyzer. Our technique is able to provide a repeatability of ±3.1 μmol kg−1, given by the pooled standard deviation over a CT range typically applied in acidification experiments. 200 μL of sample is required to perform the actual CT measurement. The total sample amount needed is 12 mL. Moreover, we show that sample filtration is applicable with only minor alteration of the CT. The method is simple, reliable and with low cumulative material costs. Hence, it is potentially attractive for all researchers experimentally manipulating the seawater carbonate system.

A Statistical Treatment of Bioassay Pour Fractions

Science.gov (United States)

Barengoltz, Jack; Hughes, David W.

2014-01-01

The binomial probability distribution is used to treat the statistics of a microbiological sample that is split into two parts, with only one part evaluated for spore count. One wishes to estimate the total number of spores in the sample based on the counts obtained from the part that is evaluated (pour fraction). Formally, the binomial distribution is recharacterized as a function of the observed counts (successes), with the total number (trials) an unknown. The pour fraction is the probability of success per spore (trial). This distribution must be renormalized in terms of the total number. Finally, the new renormalized distribution is integrated and mathematically inverted to yield the maximum estimate of the total number as a function of a desired level of confidence ( P(fraction. The extension to recovery efficiency corrections is also presented. Now the product of recovery efficiency and pour fraction may be small enough that the likely value may be much larger than the usual calculation: the number of spores divided by that product. The use of this analysis would not be limited to microbiological data.

Total organic carbon and humus fractions in restored soils from limestone quarries in semiarid climate, SE Spain

Science.gov (United States)

Luna Ramos, Lourdes; Miralles Mellado, Isabel; Ángel Domene Ruiz, Miguel; Solé Benet, Albert

2016-04-01

Mining activities generate erosion and loss of plant cover and soil organic matter (SOM), especially in arid and semiarid Mediterranean regions. A precondition for ecosystem restoration in such highly disturbed areas is the development of functional soils with sufficient organic matter. But the SOM quality is also important to long-term C stabilization. The resistance to biodegradation of recalcitrant organic matter fractions has been reported to depend on some intrinsic structural factors of humic acid substances and formation of amorphous organo-mineral recalcitrant complexes. In an experimental soil restoration in limestone quarries in the Sierra de Gádor (Almería), SE Spain, several combinations of organic amendments (sewage sludge and compost from domestic organic waste) and mulches (gravel and woodchip) were added in experimental plots using a factorial design. In each plot, 75 native plants (Anthyllis cytisoides, A. terniflora and Macrochloa tenacissima) were planted and five years after the start of the experiment total organic carbon (TOC), physico-chemical soil properties and organic C fractions (particulate organic matter, H3PO4-fulvic fraction, fulvic acids (FA), humic acids (HA) and humin) were analyzed. We observed significant differences between treatments related to the TOC content and the HA/FA ratio. Compost amendments increased the TOC, HA content and HA/FA ratio, even higher than in natural undisturbed soils, indicating an effective clay humus-complex pointing to progressively increasing organic matter quality. Soils with sewage sludge showed the lowest TOC and HA/FA ratio and accumulated a lower HA proportion indicating poorer organic matter quality and comparatively lower resilience than in natural soils and soils amended with compost.

Antioxidant Capacities of Fractions of Bamboo Shaving Extract and Their Antioxidant Components.

Science.gov (United States)

Gong, Jinyan; Huang, Jun; Xiao, Gongnian; Chen, Feng; Lee, Bolim; Ge, Qing; You, Yuru; Liu, Shiwang; Zhang, Ying

2016-07-30

This research was conducted for evaluation of antioxidant activities of four fractions from bamboo shavings extract (BSE) and their antioxidant components. The antioxidant capacities of BSE and four fractions on ABTS, DPPH, FRAP and total antioxidant capacity assays exhibited the following descending order: DF > n-butanol fraction (BF) > BSE ≈ ethyl acetate fraction (AF) > water fraction (WF). Among the identified phenolic compounds, caffeic acid exhibited the highest antioxidant capacities on DPPH, FRAP and total antioxidant capacity assays. An extremely significant positive correlation between the antioxidant activities with the contents of total flavonoids, total phenolic acids, or total phenolics was observed in this study. The result indicated that the bamboo shaving extract and its solvent fractions could act as natural antioxidants in light of their potent antioxidant activities.

DISSOLVED ORGANIC-MATTER, CADMIUM, COPPER AND ZINC IN PIG SLURRY-SIZE AND SOIL SOLUTION-SIZE EXCLUSION CHROMATOGRAPHY FRACTIONS

NARCIS (Netherlands)

DELCASTILHO, P; DALENBERG, JW; BRUNT, K; BRUINS, AP

1993-01-01

Sephadex size exclusion chromatography was used to prepare molecular size fractions from liquid pig slurry, before and after aerobic interaction with a loamy-sand soil. In the liquid fractions organic matter was characterized and some components were identified. The distribution of zinc and copper

Seasonal variations of total {sup 234}Th and dissolved {sup 238}U concentration activities in surface water of Bransfield Strait, Antarctica, from March to October 2011

Energy Technology Data Exchange (ETDEWEB)

Lapa, Flavia V.; Oliveira, Joselene de; Costa, Alice M.R., E-mail: fvlapa@ipen.br, E-mail: jolivei@ipen.br, E-mail: lice_mrc@hotmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Sao Paulo, SP (Brazil). Laboratorio de Radiometria Ambiental; Braga, Elisabete S., E-mail: edsbraga@usp.br [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Inst. Oceanografico. Lab. de Nutrientes, Micronutrientes e Tracos nos Oceanos

2013-07-01

In this study the naturally occurring radionuclides {sup 234}Th and {sup 238}U were used to investigate the magnitude of upper ocean particulate organic carbon export in Bransfield Strait, Southern Ocean. This region is the largest oceanic high-nitrate low-chlorophyll (HNLC) area in the world and is known to contribute to regulate of the atmospheric CO{sub 2} via the biological pump. Due to its different geochemical behavior in seawater, the resulting U/Th disequilibria can be easily used to constrain the transport rates of particles and reaction processes between solution and particulate phases. Sampling occurred during the summer (March and November) 2011. Total {sup 234}Th activities in surface seawater samples ranged from 1.3 to 3.7 dpm L{sup -1} (station EB 011) during March/11 campaign, while in October/11 total {sup 234}Th activity concentrations varied from 1.4 to 2.9 dpm L{sup -1}. Highest total {sup 234}Th activities were found late in the austral summer season. Activity concentrations of dissolved {sup 238}U in surface seawater varied from 2.1 to 2.4 dpm L{sup -1}. Taking into account all sampling stations established in March and October/11 the relative variability of total {sup 234}Th distribution was 22%. (author)

Arsenic speciation in total contents and bioaccessible fractions in atmospheric particles related to human intakes

International Nuclear Information System (INIS)

Huang, Minjuan; Chen, Xunwen; Zhao, Yinge; Yu Chan, Chuen; Wang, Wei; Wang, Xuemei; Wong, Ming Hung

2014-01-01

Speciation of inorganic trivalent arsenicals (iAs III ), inorganic pentavalent arsenicals (iAs V ), monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA) in total arsenic (As) content and its bioaccessible fractions contained in road dust, household air-conditioning (AC) filter dust and PM 2.5 was investigated. Inorganic As, especially iAs V , was observed as the dominant species. Physiologically based extraction test (PBET), an in-vitro gastrointestinal method, was used to estimate the oral As bioaccessibility in coarse particles and the species present in the oral bioaccessible fraction. A composite lung simulating serum was used to mimic the pulmonary condition to extract the respiratory bioaccessible As and its species in PM 2.5 . Reduction of iAs V to iAs III occurred in both in-vitro gastrointestinal and lung simulating extraction models. The inorganic As species was the exclusive species for absorption through ingestion and inhalation of atmospheric particles, which was an important exposure route to inorganic As, in addition to drinking water and food consumption. - Highlights: • Inorganic As species was the predominant species in dust and airborne particles. • Existence of iAs III in dust and airborne particles increases human health risks. • Reduction from iAs V to iAs III occurred through in-vitro gastrointestinal model. • Reduction from iAs V to iAs III occurred in the simulating pulmonary region. • Atmospheric particles were important exposure sources of inorganic As. - Atmospheric particles are important exposure sources of inorganic As, of which the bioaccessibility is dependent on the extraction phases and models used

Dissolved strontium and calcium levels in the tropical Indian Ocean

Science.gov (United States)

Steiner, Zvi; Sarkar, Amit; Turchyn, Alexandra

2017-04-01

Measurements of seawater alkalinity and dissolved calcium concentrations along oceanic transects are often used to calculate calcium carbonate precipitation and dissolution rates. Given that the distribution coefficient of strontium in CaCO3 varies greatly between different groups of organisms, adding precise measurements of dissolved strontium concentrations provides opportunities to also track relative contributions of these different groups to the regional CaCO3 cycle. However, there are several obstacles to this approach. These obstacles include unresolved systematic discrepancies between seawater calcium and alkalinity data, very large analytical noise around the calcium concentration measurements and the unconstrained role of acantharia (radiolarian precipitating SrSO4 skeletons) in the marine strontium cycle. During the first cruise of the second International Indian Ocean Expedition (IIOE-2) water samples were collected along 67°E from 9°N to 5°S to explore the dissolution rate of calcium carbonate in the water. The dissolution rate can be calculated by combining measurements of water column potential alkalinity with calcium and strontium concentrations measured by ICP-OES and calcium concentration measurements using isotope dilution thermal ionization mass spectrometry (ID-TIMS). CaCO3 mineral saturation state calculated using pH and total alkalinity suggests that along 67°E, the aragonite saturation horizon lays at depth of 500 m on both sides of the equator. Across the cruise transect, dissolved strontium concentrations increase by 2-3% along the thermocline suggesting rapid recycling of strontium rich phases. This is particularly evident just below the thermocline at 8-9°N and below 1000 m water depth, south of the equator. The deep, southern enrichment in strontium does not involve a change in the Sr/Ca ratio, suggesting that this strontium enrichment is related to CaCO3 dissolution. In contrast, in the intermediate waters of the northern part of

HB-Line Dissolver Dilution Flows and Dissolution Capability with Dissolver Charge Chute Cover Off

International Nuclear Information System (INIS)

Hallman, D.F.

2003-01-01

A flow test was performed in Scrap Recovery of HB-Line to document the flow available for hydrogen dilution in the dissolvers when the charge chute covers are removed. Air flow through the dissolver charge chutes, with the covers off, was measured. A conservative estimate of experimental uncertainty was subtracted from the results. After subtraction, the test showed that there is 20 cubic feet per minute (cfm) air flow through the dissolvers during dissolution with a glovebox exhaust fan operating, even with the scrubber not operating. This test also showed there is 6.6 cfm air flow through the dissolvers, after subtraction of experimental uncertainty if the scrubber and the glovebox exhaust fans are not operating. Three H-Canyon exhaust fans provide sufficient motive force to give this 6.6 cfm flow. Material charged to the dissolver will be limited to chemical hydrogen generation rates that will be greater than or equal to 25 percent of the Lower Flammability Limit (LFL) during normal operations. The H-Canyon fans will maintain hydrogen below LFL if electrical power is lost. No modifications are needed in HB-Line Scrap Recovery to ensure hydrogen is maintained less that LFL if the scrubber and glovebox exhaust fans are not operating

Lysine Rich Proteins in the Salt-Soluble Protein Fraction of Barley

DEFF Research Database (Denmark)

Ingversen, J.; Køie, B.

1973-01-01

Fractionation of the protein complex from Emir barley showed that the salt-soluble fraction accounts for 44% of the total lysine content but only for 2.......Fractionation of the protein complex from Emir barley showed that the salt-soluble fraction accounts for 44% of the total lysine content but only for 2....

Identification of dissolved-constituent sources in mine-site ground water using batch mixing

International Nuclear Information System (INIS)

Clark, G.M.; Williams, R.S. Jr.

1991-01-01

Batch-mixing experiments were used to help identify lithologic mineralogic sources of increased concentrations of dissolved solids in water affected by surface coal mining in northwestern Colorado. Ten overburden core samples were analyzed for mineral composition and mixed with distilled water for 90 days until mineral-water equilibrium was reached. Dissolved-solids concentrations ranged from 200 to 8,700 mg/L in water samples extracted from the mixtures after 90 days. Mass-balance simulations were conducted using the geochemical models BALANCE and WATEQF to quantify mineral-water interactions occurring in five selected sample mixtures and in water collected from a spring at a reclaimed mine site. The spring water is affected by mineral-water interactions occurring in all of lithologic units comprising the overburden. Results of the simulations indicate that oxidation of pyrite, dissolution of dolomite, gypsum, and epsomite, and cation-exchange reactions are the primary mineral-water interactions occurring in the overburden. Three lithologic units in the overburden probably contribute most of the dissolved solids to the spring water. Water sample extracts from mixtures using core from these three units accounted for 85 percent of the total dissolved solids in the 10 sample extracts. Other lithologic units in the overburden probably contribute smaller quantities of dissolved solids to the spring water

Tests of equal effect per fraction in microcolony assays of survival after fractionated irradiations

International Nuclear Information System (INIS)

Taylor, J.M.G.

1985-01-01

H.D Thames, Jr. and H.R. Withers propose a test of an equal effect per fraction in microcolony assays after fractionated radiation, in which the total effect is measured by counting microcolonies derived from surviving cells in a tissue. The factors considered to influence the cytocidal effect per fraction are incomplete repair, repopulation, and synchrony. The statistics used in the method are criticized and conditions are given under which the test should not be used. An alternative method of testing for an equal effect per fraction is proposed. The pros and cons of each test are discussed and compared using some mouse jejunal crypt cell survival data

Distributions and seasonal variations of dissolved carbohydrates in the Jiaozhou Bay, China

Science.gov (United States)

Yang, Gui-Peng; Zhang, Yan-Ping; Lu, Xiao-Lan; Ding, Hai-Bing

2010-06-01

Surface seawater samples were collected in the Jiaozhou Bay, a typical semi-closed basin located at the western part of the Shandong Peninsula, China, during four cruises. Concentrations of monosaccharides (MCHO), polysaccharides (PCHO) and total dissolved carbohydrates (TCHO) were measured with the 2,4,6-tripyridyl- s-triazine spectroscopic method. Concentrations of TCHO varied from 10.8 to 276.1 μM C for all samples and the ratios of TCHO to dissolved organic carbon (DOC) ranged from 1.1 to 67.9% with an average of 10.1%. This result indicated that dissolved carbohydrates were an important constituent of DOC in the surface seawater of the Jiaozhou Bay. In all samples, the concentrations of MCHO ranged from 2.9 to 65.9 μM C, comprising 46.1 ± 16.6% of TCHO on average, while PCHO ranged from 0.3 to 210.2 μM C, comprising 53.9 ± 16.6% of TCHO on average. As a major part of dissolved carbohydrates, the concentrations of PCHO were higher than those of MCHO. MCHO and PCHO accumulated in January and July, with minimum average concentration in April. The seasonal variation in the ratios of TCHO to DOC was related to water temperature, with high values in January and low values in July and October. The concentrations of dissolved carbohydrates displayed a decreasing trend from the coastal to the central areas. Negative correlations between concentrations of TCHO and salinity in July suggested that riverine input around the Jiaozhou Bay had an important effect on the concentrations of dissolved carbohydrates in surface seawater. The pattern of distributions of MCHO and PCHO reported in this study added to the global picture of dissolved carbohydrates distribution.

Comparison of ultrafiltration and dissolved air flotation efficiencies in industrial units during the papermaking process

OpenAIRE

Monte Lara, Concepción; Ordóñez Sanz, Ruth; Hermosilla Redondo, Daphne; Sánchez González, Mónica; Blanco Suárez, Ángeles

2011-01-01

The efficiency of an ultrafiltration unit has been studied and compared with a dissolved air flotation system to get water with a suited quality to be reused in the process. The study was done at a paper mill producing light weight coated paper and newsprint paper from 100% recovered paper. Efficiency was analysed by removal of turbidity, cationic demand, total and dissolved chemical oxygen demand, hardness, sulphates and microstickies. Moreover, the performance of the ultrafiltration unit an...

CADDIS Volume 2. Sources, Stressors and Responses: Dissolved Oxygen

Science.gov (United States)

Introduction to the dissolved oxygen module, when to list dissolved oxygen as a candidate cause, ways to measure dissolved oxygen, simple and detailed conceptual model diagrams for dissolved oxygen, references for the dissolved oxygen module.

Radiobiological arguments for and clinical possibilities of unconventional fractionating rhythms

International Nuclear Information System (INIS)

Herrmann, T.; Voigtmann, L.

1986-01-01

Radiobiological considerations are presented using unconventional fractionating rhythms. The aim of this method is to enlarge the therapeutic dimensions between maximum tumor destruction and most careful treatment of late responding cell systems. These late responding tissues show a very similar dose-time reaction, probably by reason of a causal injury on cells of the capillary endothelium. In linear-quadratic models for the estimation of the parameters of the number of fractions and total treatment period it becomes evident that a careful treatment of late responding tissue can be attained by reduction of the single dose per fraction. Because with partition of a total dose in several fractions at daily irradiation a longer repopulation period is available also for the tumor irradiations are presented, done repeatedly during the day. Accelerated fractionation (same fractionating number in reduced treatment period) are contrasted to hyperfractionation (increased fractionating number within the same total treatment period) and possibilities in application are suggested. (author)

Seasonal dynamics and conservative mixing of dissolved organic matter in the temperate eutrophic estuary Horsens Fjord

DEFF Research Database (Denmark)

Markager, Stiig; Stedmon, Colin; Søndergaard, Morten

2011-01-01

of different DOM parameters i.e. dissolved organic carbon (DOC), nitrogen (DON), and phosphorous (DOP), light absorption and eight fluorescence components, were analysed relative to conservative mixing. Many of the parameters did not behave conservatively. For DON, DOP and absorption, more than 65......This study presents the results of a year-long study investigating the characteristics of dissolved organic matter (DOM) in the Danish estuary, Horsens Fjord. The estuary is shallow with a mean depth of 2.9 m and receives high loadings of inorganic nutrients from its catchment. The behaviour......% of the freshwater concentration was removed initially at salinities below 12. At higher salinities two general patterns were identified. Concentrations of DON, DOP and four humic fluorescent fractions were not, or only weakly, related to salinity, showing that other processes than mixing were involved. Other...

Concentration and distribution of dissolved amino acids in a shallow hydrothermal system, Vulcano Island (Italy)

Energy Technology Data Exchange (ETDEWEB)

Svensson, E.; Skoog, A. [University of Connecticut, Groton, CT (United States). Dept. of Marine Sciences; Amend, J.P. [Washington University, St. Louis, MO (United States). Dept. of Earth and Planetary Sciences

2004-09-01

Hydrothermal systems are known to harbour a large number of microorganisms, but the organic chemical composition of the solution that comprises their potential substrate is largely unknown. Concentrations and distributions of dissolved free amino acids (DFAA) and dissolved combined amino acids (DCAA) were determined in fluids from the moderate-temperature (42-89{sup o}C), shallow hydrothermal system on the volcanically active island of Vulcano, Italy. The seven samples represent three different geological settings on the island; shallow ({approx} 1 m) submarine vents, geothermal wells, and seeps in heated beach sediments, in addition to ambient local seawater from the bay, Baia di Levante. All hydrothermal sites, with one exception, had TDAA concentrations that were 3-114 times higher than local seawater in Baia di Levante. There were large similarities in amino acid concentration and composition among samples from the same geological setting. The highest amino acid concentrations were found at sites with acidic and reducing conditions, which also had the largest freshwater component. An unusually high fraction of the TDAA pool was represented by DFAA (33-87%), possibly due to in situ acid hydrolysis of DCAA to DFAA. Both DFAA and DCAA concentrations were correlated to DOC, indicating similar source and sink functions for these pools. The yield of TDAA (TDAA-carbon as fraction of organic carbon) ranged from 2% to 25%, which is high compared with non-hydrothermal settings, and indicates high biological lability. The mole fraction of {beta}-alanine plus {gamma}-aminobutyric acid (% BALA + GABA) was 2-2.7% of TDAA, also indicating high biological lability. Owing to the high over-all amino acid concentrations, the high fraction of DFAAs, and the high biological lability of the organic matter, organic matter in general and amino acids specifically could represent significant carbon and energy sources for archaea and bacteria in this hydrothermal system. The clear

Reducing emissions from uranium dissolving

International Nuclear Information System (INIS)

Griffith, W.L.; Compere, A.L.; Huxtable, W.P.; Googin, J.M.

1992-10-01

This study was designed to assess the feasibility of decreasing NO x emissions from the current uranium alloy scrap tray dissolving facility. In the current process, uranium scrap is dissolved in boiling nitric acid in shallow stainless-steel trays. As scrap dissolves, more metal and more nitric acid are added to the tray by operating personnel. Safe geometry is assured by keeping liquid level at or below 5 cm, the depth of a safe infinite slab. The accountability batch control system provides additional protection against criticality. Both uranium and uranium alloys are dissolved. Nitric acid is recovered from the vapors for reuse. Metal nitrates are sent to uranium recovery. Brown NO x fumes evolved during dissolving have occasionally resulted in a visible plume from the trays. The fuming is most noticeable during startup and after addition of fresh acid to a tray. Present environmental regulations are expected to require control of brown NO x emissions. A detailed review of the literature, indicated the feasibility of slightly altering process chemistry to favor the production of NO 2 which can be scrubbed and recycled as nitric acid. Methods for controlling the process to manage offgas product distribution and to minimize chemical reaction hazards were also considered

Anticonvulsant properties of the total alkaloid fraction of Rauvolfia ligustrina Roem. et Schult. in male mice

Directory of Open Access Journals (Sweden)

Lucindo J. Quintans-Júnior

Full Text Available Rauvolfia ligustrina Roem et. Schult (Apocynaceae, commonly known as "paratudo" and "arrebenta-boi" is a small tree found in Brazilian Northeastern. Previous studies have demonstrated depressant and anticonvulsant properties of the ethanol extract of Rauvolfia ligustrina. The aim of the present study was the determination of the lethal dose 50% (LD50 and the effects of total alkaloid fraction (TAF of the aerial parts of R. ligustrina in animal models of convulsion. It was found that the acute toxicity of TAF was 127.8 (112.5-145.2 mg/kg (i.p. in mice. TAF (20 mg/kg, ip significantly increased (p < 0.05 the latencies of clonic seizures induced by pentylenetetrazol (PTZ and picrotoxin (PIC. However, TAF did not protect the animals in maximal electroshock (MES induced seizures. These results suggest that TAF of R. ligustrina possesses anticonvulsant properties.

Changes in the composition and bioavailability of dissolved organic matter during sea ice formation

DEFF Research Database (Denmark)

Jørgensen, Linda; Stedmon, Colin A.; Kaartokallio, Hermanni

2015-01-01

matter (FDOM) fractions in sea ice, brines (contained in small pores between the ice crystals), and the underlying seawater during a 14 d experiment. Two series of mesocosms were used: one with seawater alone and one with seawater enriched with humic-rich river water. Abiotic processes increased...... processes such as sea ice formation as the source of the significant DOM removal in the Arctic Ocean. We present the results of a mesocosm experiment designed to investigate how sea ice formation affects DOM composition and bioavailability. We measured the change in different fluorescent dissolved organic...... the humic-like FDOM signal in the seawater below the ice during the initial ice formation. Humic-like FDOM fractions with a marine signal were preferentially retained in sea ice (relative to salinity), whereas humic-like FDOM with a terrestrial signal behaved more conservatively with respect to salinity...

Dissolved inorganic carbon, total alkalinity, pH, and other variables collected from surface discrete observations using spectrophotometer and other instruments from NOAA Ship Henry B. Bigelow off the Northeastern coast of the United States from 2014-09-10 to 2014-11-05 (NCEI Accession 0138983)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains surface measurements of dissolved inorganic, total alkalinity, pH measurements off the Northeastern coast of the United States....

Incorporation of inorganic mercury (Hg2+) in pelagic food webs of ultraoligotrophic and oligotrophic lakes: The role of different plankton size fractions and species assemblages

International Nuclear Information System (INIS)

Soto Cárdenas, Carolina; Diéguez, Maria C.; Ribeiro Guevara, Sergio; Marvin-DiPasquale, Mark; Queimaliños, Claudia P.

2014-01-01

In lake food webs, pelagic basal organisms such as bacteria and phytoplankton incorporate mercury (Hg 2+ ) from the dissolved phase and pass the adsorbed and internalized Hg to higher trophic levels. This experimental investigation addresses the incorporation of dissolved Hg 2+ by four plankton fractions (picoplankton: 0.2–2.7 μm; pico + nanoplankton: 0.2–20 μm; microplankton: 20–50 μm; and mesoplankton: 50–200 μm) obtained from four Andean Patagonian lakes, using the radioisotope 197 Hg 2+ . Species composition and abundance were determined in each plankton fraction. In addition, morphometric parameters such as surface and biovolume were calculated using standard geometric models. The incorporation of Hg 2+ in each plankton fraction was analyzed through three concentration factors: BCF (bioconcentration factor) as a function of cell or individual abundance, SCF (surface concentration factor) and VCF (volume concentration factor) as functions of individual exposed surface and biovolume, respectively. Overall, this investigation showed that through adsorption and internalization, pico + nanoplankton play a central role leading the incorporation of Hg 2+ in pelagic food webs of Andean lakes. Larger planktonic organisms included in the micro- and mesoplankton fractions incorporate Hg 2+ by surface adsorption, although at a lesser extent. Mixotrophic bacterivorous organisms dominate the different plankton fractions of the lakes connecting trophic levels through microbial loops (e.g., bacteria–nanoflagellates–crustaceans; bacteria–ciliates–crustaceans; endosymbiotic algae–ciliates). These bacterivorous organisms, which incorporate Hg from the dissolved phase and through their prey, appear to explain the high incorporation of Hg 2+ observed in all the plankton fractions. - Highlights: • Hg 2+ incorporation in lake plankton fractions was studied using the isotope 197 Hg 2+ . • Hg 2+ incorporation was assessed using three different

Spectroscopic detection of a ubiquitous dissolved pigment degradation product in subsurface waters of the global ocean

Directory of Open Access Journals (Sweden)

R. Röttgers

2012-07-01

Full Text Available Measurements of light absorption by chromophoric dissolved organic matter (CDOM from subsurface waters of the tropical Atlantic and Pacific Oceans showed a distinct absorption shoulder at 410–415 nm. This indicates an underlying absorption of a pigment whose occurrence is partly correlated with the apparent oxygen utilization (AOU but also found in the deep chlorophyll maximum. A similar absorption maximum at ~415 nm was also found in the particulate fraction of samples taken below the surface mixing layer and is usually attributed to absorption by respiratory pigments of heterotrophic unicellular organisms. In our study, fluorescence measurements of pre-concentrated dissolved organic matter (DOM samples from 200–6000 m confirmed a previous study suggesting that the absorption at ~415 nm was related to fluorescence at 650 nm in the oxygen minimum zone. The absorption characteristics of this fluorophore was examined by fluorescence emission/excitation analysis and showed a clear excitation maximum at 415 nm that could be linked to the absorption shoulder in the CDOM spectra. The spectral characteristics of the substance found in the dissolved and particulate fraction did not match with those of chlorophyll a degradation products (as found in a sample from the sea surface but can be explained by the occurrence of porphyrin pigments from either heterotrophs or autotrophs. Combining the observations of the fluorescence and the 415-nm absorption shoulder suggests that there are high concentrations of a pigment degradation product in subsurface DOM of all major oceans. Most pronouncedly we found this signal in the deep chlorophyll maximum and the oxygen minimum zone of tropical regions. The origin, chemical nature, turnover rate, and fate of this molecule is so far unknown.

Dissolved and colloidal trace elements in the Mississippi River delta outflow after Hurricanes Katrina and Rita

Science.gov (United States)

Shim, Moo-Joon; Swarzenski, Peter W.; Shiller, Alan M.

2012-07-01

The Mississippi River delta outflow region is periodically disturbed by tropical weather systems including major hurricanes, which can terminate seasonal bottom water hypoxia and cause the resuspension of shelf bottom sediments which could result in the injection of trace elements into the water column. In the summer of 2005, Hurricanes Katrina and Rita passed over the Louisiana Shelf within a month of each other. Three weeks after Rita, we collected water samples in the Mississippi River delta outflow, examining the distributions of trace elements to study the effect of Hurricanes Katrina and Rita. We observed limited stratification on the shelf and bottom waters that were no longer hypoxic. This resulted, for instance, in bottom water dissolved Mn being lower than is typically observed during hypoxia, but with concentrations still compatible with Mn-O2 trends previously reported. Interestingly, for no element were we able to identify an obvious effect of sediment resuspension on its distribution. In general, elemental distributions were compatible with previous observations in the Mississippi outflow system. Co and Re, which have not been reported for this system previously, showed behavior consistent with other systems: input for Co likely from desorption and conservative mixing for Re. For Cs, an element for which there is little information regarding its estuarine behavior, conservative mixing was also observed. Our filtration method, which allowed us to distinguish the dissolved (<0.02 μm) from colloidal (0.02-0.45 μm) phase, revealed significant colloidal fractions for Fe and Zn, only. For Fe, the colloidal phase was the dominant fraction and was rapidly removed at low salinity. Dissolved Fe, in contrast, persisted out to mid-salinities, being removed in a similar fashion to nitrate. This ability to distinguish the smaller Fe (likely dominantly organically complexed) from larger colloidal suspensates may be useful in better interpreting the bioavailablity

Nitrous oxide emissions and dissolved oxygen profiling in a full-scale nitrifying activated sludge treatment plant.

Science.gov (United States)

Aboobakar, Amina; Cartmell, Elise; Stephenson, Tom; Jones, Mark; Vale, Peter; Dotro, Gabriela

2013-02-01

This paper reports findings from online, continuous monitoring of dissolved and gaseous nitrous oxide (N₂O), combined with dissolved oxygen (DO) and ammonia loading, in a full-scale nitrifying activated sludge plant. The study was conducted over eight weeks, at a 210,000 population equivalent sewage treatment works in the UK. Results showed diurnal variability in the gaseous and dissolved N₂O emissions, with hourly averages ranging from 0 to 0.00009 kgN₂O-N/h for dissolved and 0.00077-0.0027 kgN₂O-N/h for gaseous nitrous oxide emissions respectively, per ammonia loading, depending on the time of day. Similarly, the spatial variability was high, with the highest emissions recorded immediately after the anoxic zone and in the final pass of the aeration lane, where ammonia concentrations were typically below 0.5 mg/L. Emissions were shown to be negatively correlated to dissolved oxygen, which fluctuated between 0.5 and 2.5 mgO₂/L, at the control set point of 1.5 mgO₂/L. The resulting dynamic DO conditions are known to favour N₂O production, both by autotrophic and heterotrophic processes in mixed cultures. Average mass emissions from the lane were greater in the gaseous (0.036% of the influent total nitrogen) than in the dissolved (0.01% of the influent total nitrogen) phase, and followed the same diurnal and spatial patterns. Nitrous oxide emissions corresponded to over 34,000 carbon dioxide equivalents/year, adding 13% to the carbon footprint associated with the energy requirements of the monitored lane. A clearer understanding of emissions obtained from real-time data can help towards finding the right balance between improving operational efficiency and saving energy, without increasing N₂O emissions. Copyright © 2012 Elsevier Ltd. All rights reserved.

Coupling loss characteristics of runoff-sediment-adsorbed and dissolved nitrogen and phosphorus on bare loess slope.

Science.gov (United States)

Wu, Lei; Qiao, Shanshan; Peng, Mengling; Ma, Xiaoyi

2018-05-01

Soil and nutrient loss is a common natural phenomenon but it exhibits unclear understanding especially on bare loess soil with variable rainfall intensity and slope gradient, which makes it difficult to design control measures for agricultural diffuse pollution. We employ 30 artificial simulated rainfalls (six rainfall intensities and five slope gradients) to quantify the coupling loss correlation of runoff-sediment-adsorbed and dissolved nitrogen and phosphorus on bare loess slope. Here, we show that effects of rainfall intensity on runoff yield was stronger than slope gradient with prolongation of rainfall duration, and the effect of slope gradient on runoff yield reduced gradually with increased rainfall intensity. But the magnitude of initial sediment yield increased significantly from an average value of 6.98 g at 5° to 36.08 g at 25° with increased slope gradient. The main factor of sediment yield would be changed alternately with the dual increase of slope gradient and rainfall intensity. Dissolved total nitrogen (TN) and dissolved total phosphorus (TP) concentrations both showed significant fluctuations with rainfall intensity and slope gradient, and dissolved TP concentration was far less than dissolved TN. Under the double influences of rainfall intensity and slope gradient, adsorbed TN concentration accounted for 7-82% of TN loss concentration with an average of 58.6% which was the main loss form of soil nitrogen, adsorbed TP concentration accounted for 91.8-98.7% of TP loss concentration with an average of 96.6% which was also the predominant loss pathway of soil phosphorus. Nitrate nitrogen (NO 3 - -N) accounted for 14.59-73.92% of dissolved TN loss, and ammonia nitrogen (NH 4 + -N) accounted for 1.48-18.03%. NO 3 - -N was the main loss pattern of TN in runoff. Correlation between dissolved TN, runoff yield, and rainfall intensity was obvious, and a significant correlation was also found between adsorbed TP, sediment yield, and slope gradient. Our

Towards explaining excess CO2 production in wetlands - the roles of solid and dissolved organic matter as electron acceptors and of substrate quality

Science.gov (United States)

Knorr, Klaus-Holger; Gao, Chuanyu; Agethen, Svenja; Sander, Michael

2017-04-01

of total NOM could explain 22-38 % of excess CO2 production in a weakly decomposed peat, 30-67 % of excess CO2 production in a well decomposed peat, and >100 % of excess CO2 production in a peat that had been exposed to oxygen for > 1 year. In this latter peat, EAC by OM explained 45-57 % of CO2 production, while reduction of sulfate available in this material readily explained the remaining fraction. Despite having considerable uncertainty arising from methodological challenges, the collected data demonstrated that accounting for the EACs of solid and dissolved OM may fully explain excess CO2 production. As we conservatively assumed a carbon oxidation state of zero for our budget calculations, a higher oxidation state of C in NOM as suggested by elemental analysis would result in electron equivalent budgets between EAC decreases and CO2 formation even closer to 100 %. A higher oxidation state of mineralized carbon seemed especially likely for weakly decomposed peat, as this material had higher concentrations of oxygen and showed the largest percentage of formed CO2 that could not be explained based on OM reduction.

[Distributions and seasonal variations of total dissolved inorganic arsenic in the estuaries and coastal area of eastern Hainan].

Science.gov (United States)

Cao, Xiu-Hong; Ren, Jing-Ling; Zhang, Gui-Ling; Zhang, Jin-E; Du, Jin-Zhou; Zhu, De-Di

2012-03-01

The concentrations of total dissolved inorganic arsenic (TDIAs) were measured by Hydride Generation-Atomic Fluorescence Spectrometry (HG-AFS). Two cruises were carried out in the river, estuary, coastal area and groundwater of eastern Hainan in December 2006 and August 2007. The concentrations of TDIAs in the Wanquan and Wenchang/Wenjiao rivers and their estuaries, coastal area in December 2006 were 4.0-9.4, 1.3-13.3, 13.3-17.3 nmol x L(-1), respectively. The concentrations of TDIAs in the Wanquan and Wenchang/Wenjiao rivers and their estuaries, coastal area in August 2007 were 1.6-15.5, 2.4-15.9, 10.8-17.6 nmol x L(-1), respectively. There was no significantly seasonal variation of TDIAs in the rivers and estuaries during the dry and wet seasons. Compared with other areas in the world, the concentration of TDIAs in the Eastern Hainan remained at pristine levels. TDIAs showed conservatively mixing in the both estuaries. The concentration of TDIAs of groundwater was below detection limit (BDL)-41.7 nmol x L(-1). The submarine groundwater discharge (SGD) to the coastal area was estimated in the drainage basin of Wenchang/Wenjiao river based on the average concentration of TDIAs in the groundwater and SGD water discharge, with the value of 1 153 mol x a(-1). Budget estimation indicated that the SGD discharge is one of the important sources of arsenic in the coastal area.

Incorporation of inorganic mercury (Hg²⁺) in pelagic food webs of ultraoligotrophic and oligotrophic lakes: the role of different plankton size fractions and species assemblages.

Science.gov (United States)

Soto Cárdenas, Carolina; Diéguez, Maria C; Ribeiro Guevara, Sergio; Marvin-DiPasquale, Mark; Queimaliños, Claudia P

2014-10-01

In lake food webs, pelagic basal organisms such as bacteria and phytoplankton incorporate mercury (Hg(2+)) from the dissolved phase and pass the adsorbed and internalized Hg to higher trophic levels. This experimental investigation addresses the incorporation of dissolved Hg(2+) by four plankton fractions (picoplankton: 0.2-2.7 μm; pico+nanoplankton: 0.2-20 μm; microplankton: 20-50 μm; and mesoplankton: 50-200 μm) obtained from four Andean Patagonian lakes, using the radioisotope (197)Hg(2+). Species composition and abundance were determined in each plankton fraction. In addition, morphometric parameters such as surface and biovolume were calculated using standard geometric models. The incorporation of Hg(2+) in each plankton fraction was analyzed through three concentration factors: BCF (bioconcentration factor) as a function of cell or individual abundance, SCF (surface concentration factor) and VCF (volume concentration factor) as functions of individual exposed surface and biovolume, respectively. Overall, this investigation showed that through adsorption and internalization, pico+nanoplankton play a central role leading the incorporation of Hg(2+) in pelagic food webs of Andean lakes. Larger planktonic organisms included in the micro- and mesoplankton fractions incorporate Hg(2+) by surface adsorption, although at a lesser extent. Mixotrophic bacterivorous organisms dominate the different plankton fractions of the lakes connecting trophic levels through microbial loops (e.g., bacteria-nanoflagellates-crustaceans; bacteria-ciliates-crustaceans; endosymbiotic algae-ciliates). These bacterivorous organisms, which incorporate Hg from the dissolved phase and through their prey, appear to explain the high incorporation of Hg(2+) observed in all the plankton fractions. Copyright © 2014 Elsevier B.V. All rights reserved.

Experimental evaporation of hyperacid brines: Effects on chemical composition and chlorine isotope fractionation

Science.gov (United States)

Rodríguez, Alejandro; van Bergen, Manfred J.; Eggenkamp, H. G. M.

2018-02-01

Hyperacid brines from active volcanic lakes are some of the chemically most complex aqueous solutions on Earth. Their compositions provide valuable insights into processes of elemental transfer from a magma body to the surface and interactions with solid rocks and the atmosphere. This paper describes changes in chemical and δ37Cl signatures observed in a 1750 h isothermal evaporation experiment on hyperacid (pH 0.1) sulphate-chloride brine water from the active lake of Kawah Ijen volcano (Indonesia). Although gypsum was the only evaporite mineral identified in the evolving brine, decreasing Si concentrations may ultimately result in amorphous silica precipitation. Geochemical simulations predict the additional formation of elemental sulphur at lower water activities (aH2O ≤ 0.65) that were not reached in the experiment. Absence of other sulphates and halides despite the high load of dissolved elements (initial TDS ca. 100 g/kg) can be attributed to increased solubility of metals, promoted by extensive formation of complexes between the variety of cations and the major anions (HSO4-, Cl-, F-) present. Chlorine deviations from a conservative behaviour point to losses of gaseous hydrogen chloride (HCl(g)) and consequently an increase in Br/Cl ratios. Chlorine isotope fractionation that accompanied the escape of HCl(g) showed a marked change in sign and magnitude in the course of progressive evaporation of the brine. The calculated factor of fractionation between HCl(g) and dissolved Cl for the initial interval (before 500 h) is positive (1000lnαHCl(g)-Cldiss. = + 1.55 ± 0.49‰to + 3.37 ± 1.11‰), indicating that, at first, the escaping HCl(g) was isotopically heavier than the dissolved Cl remaining in the brine. Conversely, fractionation shifted to the opposite direction in the subsequent interval (1000lnαHCl(g)-Cldiss. = 5.67 ± 0.17‰to - 5.64 ± 0.08‰), in agreement with values reported in literature. It is proposed that Cl isotopic fractionation in

[Soil organic carbon fractionation methods and their applications in farmland ecosystem research: a review].

Science.gov (United States)

Zhang, Guo; Cao, Zhi-ping; Hu, Chan-juan

2011-07-01

Soil organic carbon is of heterogeneity in components. The active components are sensitive to agricultural management, while the inert components play an important role in carbon fixation. Soil organic carbon fractionation mainly includes physical, chemical, and biological fractionations. Physical fractionation is to separate the organic carbon into active and inert components based on the density, particle size, and its spatial distribution; chemical fractionation is to separate the organic carbon into various components based on the solubility, hydrolizability, and chemical reactivity of organic carbon in a variety of extracting agents. In chemical fractionation, the dissolved organic carbon is bio-available, including organic acids, phenols, and carbohydrates, and the acid-hydrolyzed organic carbon can be divided into active and inert organic carbons. Simulated enzymatic oxidation by using KMnO4 can separate organic carbon into active and non-active carbon. Biological fractionation can differentiate microbial biomass carbon and potential mineralizable carbon. Under different farmland management practices, the chemical composition and pool capacity of soil organic carbon fractions will have different variations, giving different effects on soil quality. To identify the qualitative or quantitative relationships between soil organic carbon components and carbon deposition, we should strengthen the standardization study of various fractionation methods, explore the integrated application of different fractionation methods, and sum up the most appropriate organic carbon fractionation method or the appropriate combined fractionation methods for different farmland management practices.

Intervals between multiple fractions per day

International Nuclear Information System (INIS)

Fowler, J.F.

1988-01-01

Assuming the linear quadratic model for dose-response curves enables the proportion of repairable damage to be calculated for any size of dose per fraction. It is given by the beta (dose squared) term, and represents a larger proportion of the total damage for larger doses per fraction, but also for late-reacting than for early-reacting tissues. For example at 2 Gy per fraction, repairable damage could represent nearly half the total damage in late-reacting tissues but only one fifth in early-reacting tissues. Even if repair occurs at the same rate in both tissues, it will obviously take longer for 50% of the damage to fade to an undetectable level (3 or 5%) than for 20% to do so. This means that late reactions require longer intervals than early reactions when multiple fraction per day radiotherapy is planned, even if the half-lives of repair are not different. (orig.)

Importance of Dissolved Neutral Hg-Sulfides, Energy Rich Organic Matter and total Hg Concentrations for Methyl Mercury Production in Sediments

Science.gov (United States)

Drott, A.; Skyllberg, U.

2007-12-01

brackish waters (palgae and bacteria) in the sediment and a high annual temperature sum, resulted in high methylation rates. In conclusion, concentrations of neutral Hg-sulfides and availability of energy rich organic matter, but also total Hg concentrations in sediments are important factors behind net production and accumulation of MeHg . References: (1) Drott et. al. submitted, (2) Drott, A.; Lambertsson, L.; Björn, E.; Skyllberg, U. Importance of dissolved neutral mercury sulfides for methyl mercury production in contaminated sediments. Environmental Science & Technology 2007, 41, 2270-2276.

Method of dissolving metal ruthenium

International Nuclear Information System (INIS)

Tsuno, Masao; Soda, Yasuhiko; Kuroda, Sadaomi; Koga, Tadaaki.

1988-01-01

Purpose: To dissolve and clean metal ruthenium deposited to the inner surface of a dissolving vessel for spent fuel rods. Method: Metal ruthenium is dissolved in a solution of an alkali metal hydroxide to which potassium permanganate is added. As the alkali metal hydroxide used herein there can be mentioned potassium hydroxide, sodium hydroxide and lithium hydroxide can be mentioned, which is used as an aqueous solution from 5 to 20 % concentration in view of the solubility of metal ruthenium and economical merit. Further, potassium permanganate is used by adding to the solution of alkali metal hydroxide at a concentration of 1 to 5 %. (Yoshihara, H.)

Octanol-solubility of dissolved and particulate trace metals in contaminated rivers: implications for metal reactivity and availability.

Science.gov (United States)

Turner, Andrew; Mawji, Edward

2005-05-01

The lipid-like, amphiphilic solvent, n-octanol, has been used to determine a hydrophobic fraction of dissolved and particulate trace metals (Al, Cd, Co, Cu, Mn, Ni, Pb, Zn) in contaminated rivers. In a sample from the River Clyde, southwest Scotland, octanol-solubility was detected for all dissolved metals except Co, with conditional octanol-water partition coefficients, D(ow), ranging from about 0.2 (Al and Cu) to 1.25 (Pb). In a sample taken from the River Mersey, northwest England, octanol-solubility was detected for dissolved Al and Pb, but only after sample aliquots had been spiked with individual ionic metal standards and equilibrated. Spiking of the River Clyde sample revealed competition among different metals for hydrophobic ligands. Metal displacement from hydrophobic complexes was generally most significant following the addition of ionic Al or Pb, although the addition of either of these metals had little effect on the octanol-solubility of the other. In both river water samples hydrophobic metals were detected on the suspended particles retained by filtration following their extraction in n-octanol. In general, particulate Cu and Zn (up to 40%) were most available, and Al, Co and Pb most resistant (octanol extraction. Distribution coefficients defining the concentration ratio of octanol-soluble particle-bound metal to octanol-soluble dissolved metal were in the range 10(3.3)-10(5.3)mlg(-1). The presence of hydrophobic dissolved and particulate metal species has implications for our understanding of the biogeochemical behaviour of metals in aquatic environments. Specifically, such species are predicted to exhibit characteristics of non-polar organic contaminants, including the potential to penetrate the lipid bilayer. Current strategies for assessing the bioavailability and toxicity of dissolved and particulate trace metals in natural waters may, therefore, require revision.

EFFECTIVENESS OF USING DILUTE OXALIC ACID TO DISSOLVE HIGH LEVEL WASTE IRON BASED SLUDGE SIMULANT

International Nuclear Information System (INIS)

Ketusky, E

2008-01-01

At the Savannah River Site (SRS), near Aiken South Carolina, there is a crucial need to remove residual quantities of highly radioactive iron-based sludge from large select underground storage tanks (e.g., 19,000 liters of sludge per tank), in order to support tank closure. The use of oxalic acid is planned to dissolve the residual sludge, hence, helping in the removal. Based on rigorous testing, primarily using 4 and 8 wt% oxalic acid solutions, it was concluded that the more concentrated the acid, the greater the amount of residual sludge that would be dissolved; hence, a baseline technology on using 8 wt% oxalic acid was developed. In stark contrast to the baseline technology, reports from other industries suggest that the dissolution will most effectively occur at 1 wt% oxalic acid (i.e., maintaining the pH near 2). The driver for using less oxalic acid is that less (i.e., moles) would decrease the severity of the downstream impacts (i.e., required oxalate solids removal efforts). To determine the initial feasibility of using 1 wt% acid to dissolve > 90% of the sludge solids, about 19,000 liters of representative sludge was modeled using about 530,000 liters of 0 to 8 wt% oxalic acid solutions. With the chemical thermodynamic equilibrium based software results showing that 1 wt% oxalic acid could theoretically work, simulant dissolution testing was initiated. For the dissolution testing, existing simulant was obtained, and an approximate 20 liter test rig was built. Multiple batch dissolutions of both wet and air-dried simulant were performed. Overall, the testing showed that dilute oxalic acid dissolved a greater fraction of the stimulant and resulted in a significantly larger acid effectiveness (i.e., grams of sludge dissolved/mole of acid) than the baseline technology. With the potential effectiveness confirmed via simulant testing, additional testing, including radioactive sludge testing, is planned

Diel production and microheterotrophic utilization of dissolved free amino acids in waters off southern California

International Nuclear Information System (INIS)

Carlucci, A.F.; Craven, D.B.; Henrichs, S.M.

1984-01-01

Diel patterns of dissolved free amino acid (DFAA) concentration and microheterotrophic utilization were examined in the spring and fall of 1981 in euphotic waters from the base of the mixed layer off the southern California coast. The average depths of the isotherms sampled were 19.2 m for spring and 9.0 for fall. Total DFAA levels were generally higher in the spring than in the fall, 18 to 66 nM and 14 to 20 nM, respectively. Two daily concentration maxima and minima were observed for total DFAAs as well as for most individual DFAAs. Maxima were usually measured in the mid-dark period and in the early afternoon; minima were typically observed in early morning and late afternoon. Bacterial cell numbers reached maximal values near midnight in both seasons. The increases coincided with one of the total DFAA maxima. The second total DFAA maximum occurred in early to midafternoon, during the time of maximum photosynthetic carbon production and rapid dissolved amino acid utilization. Microbial metabolism (incorporation plus respiration) of selected 3 H-amino acids was 2.7 to 4.1 times greater during the daylight hours. DFAA turnover times, based on these metabolic measurements, ranged between 11 and 36 h for the amino acids tested, and rates were 1.7 to 3.7 times faster in the daylight hours than at night. DFAA distributions were related to primary production and chlorophyll a concentrations. Amino acids were estimated to represent 9 to 45% of the total phytoplankton exudate. Microheterotrophic utilization or production of total protein amino acids was estimated as 3.6 μg of C liter -1 day -1 in spring and 1.9 μg of C liter -1 day -1 in the fall. Assimilation efficiency for dissolved amino acids averaged 65% for marine microheterotrophs

Determination of isotope fractionation effect using a double spike (242Pu+240Pu) during the mass spectrometric analysis of plutonium

International Nuclear Information System (INIS)

Chitambar, S.A.; Parab, A.R.; Khodade, P.S.; Jain, H.C.

1986-01-01

Isotope fractionation effect during the mass spectrometric analysis of plutonium has been investigated using a double spike ( 242 Pu+ 240 Pu) and the determination of concentration of plutonium in dissolver solution of irradiated fuel is reported. (author). 6 refs., 2 tables

Incorporation of inorganic mercury (Hg{sup 2+}) in pelagic food webs of ultraoligotrophic and oligotrophic lakes: The role of different plankton size fractions and species assemblages

Energy Technology Data Exchange (ETDEWEB)

Soto Cárdenas, Carolina, E-mail: sotocardenascaro@gmail.com [Laboratorio de Fotobiología, Instituto de Investigaciones en Biodiversidad y Medioambiente (INIBIOMA, UNComahue-CONICET), Quintral 1250, 8400 San Carlos de Bariloche, Río Negro (Argentina); Diéguez, Maria C. [Laboratorio de Fotobiología, Instituto de Investigaciones en Biodiversidad y Medioambiente (INIBIOMA, UNComahue-CONICET), Quintral 1250, 8400 San Carlos de Bariloche, Río Negro (Argentina); Ribeiro Guevara, Sergio [Laboratorio de Análisis por Activación Neutrónica, CAB, CNEA, Av. Bustillo Km 9.5, 8400, San Carlos de Bariloche, Río Negro (Argentina); Marvin-DiPasquale, Mark [United States Geological Survey, 345 Middlefield Rd./MS 480, Menlo Park, CA 94025 (United States); Queimaliños, Claudia P. [Laboratorio de Fotobiología, Instituto de Investigaciones en Biodiversidad y Medioambiente (INIBIOMA, UNComahue-CONICET), Quintral 1250, 8400 San Carlos de Bariloche, Río Negro (Argentina)

2014-10-01

In lake food webs, pelagic basal organisms such as bacteria and phytoplankton incorporate mercury (Hg{sup 2+}) from the dissolved phase and pass the adsorbed and internalized Hg to higher trophic levels. This experimental investigation addresses the incorporation of dissolved Hg{sup 2+} by four plankton fractions (picoplankton: 0.2–2.7 μm; pico + nanoplankton: 0.2–20 μm; microplankton: 20–50 μm; and mesoplankton: 50–200 μm) obtained from four Andean Patagonian lakes, using the radioisotope {sup 197}Hg{sup 2+}. Species composition and abundance were determined in each plankton fraction. In addition, morphometric parameters such as surface and biovolume were calculated using standard geometric models. The incorporation of Hg{sup 2+} in each plankton fraction was analyzed through three concentration factors: BCF (bioconcentration factor) as a function of cell or individual abundance, SCF (surface concentration factor) and VCF (volume concentration factor) as functions of individual exposed surface and biovolume, respectively. Overall, this investigation showed that through adsorption and internalization, pico + nanoplankton play a central role leading the incorporation of Hg{sup 2+} in pelagic food webs of Andean lakes. Larger planktonic organisms included in the micro- and mesoplankton fractions incorporate Hg{sup 2+} by surface adsorption, although at a lesser extent. Mixotrophic bacterivorous organisms dominate the different plankton fractions of the lakes connecting trophic levels through microbial loops (e.g., bacteria–nanoflagellates–crustaceans; bacteria–ciliates–crustaceans; endosymbiotic algae–ciliates). These bacterivorous organisms, which incorporate Hg from the dissolved phase and through their prey, appear to explain the high incorporation of Hg{sup 2+} observed in all the plankton fractions. - Highlights: • Hg{sup 2+} incorporation in lake plankton fractions was studied using the isotope {sup 197}Hg{sup 2+}. • Hg{sup 2

Homogenization versus homogenization-free method to measure muscle glycogen fractions.

Science.gov (United States)

Mojibi, N; Rasouli, M

2016-12-01

The glycogen is extracted from animal tissues with or without homogenization using cold perchloric acid. Three methods were compared for determination of glycogen in rat muscle at different physiological states. Two groups of five rats were kept at rest or 45 minutes muscular activity. The glycogen fractions were extracted and measured by using three methods. The data of homogenization method shows that total glycogen decreased following 45 min physical activity and the change occurred entirely in acid soluble glycogen (ASG), while AIG did not change significantly. Similar results were obtained by using "total-glycogen-fractionation methods". The findings of "homogenization-free method" indicate that the acid insoluble fraction (AIG) was the main portion of muscle glycogen and the majority of changes occurred in AIG fraction. The results of "homogenization method" are identical with "total glycogen fractionation", but differ with "homogenization-free" protocol. The ASG fraction is the major portion of muscle glycogen and is more metabolically active form.

Concentration, flux, and trend estimates with uncertainty for nutrients, chloride, and total suspended solids in tributaries of Lake Champlain, 1990–2014

Science.gov (United States)

Medalie, Laura

2016-12-20

The U.S. Geological Survey, in cooperation with the New England Interstate Water Pollution Control Commission and the Vermont Department of Environmental Conservation, estimated daily and 9-month concentrations and fluxes of total and dissolved phosphorus, total nitrogen, chloride, and total suspended solids from 1990 (or first available date) through 2014 for 18 tributaries of Lake Champlain. Estimates of concentration and flux, provided separately in Medalie (2016), were made by using the Weighted Regressions on Time, Discharge, and Season (WRTDS) regression model and update previously published WRTDS model results with recent data. Assessment of progress towards meeting phosphorus-reduction goals outlined in the Lake Champlain management plan relies on annual estimates of phosphorus flux. The percent change in annual concentration and flux is provided for two time periods. The R package EGRETci was used to estimate the uncertainty of the trend estimate. Differences in model specification and function between this study and previous studies that used WRTDS to estimate concentration and flux using data from Lake Champlain tributaries are described. Winter data were too sparse and nonrepresentative to use for estimates of concentration and flux but were sufficient for estimating the percentage of total annual flux over the period of record. Median winter-to-annual fractions ranged between 21 percent for total suspended solids and 27 percent for dissolved phosphorus. The winter contribution was largest for all constituents from the Mettawee River and smallest from the Ausable River. For the full record (1991 through 2014 for total and dissolved phosphorus and chloride and 1993 through 2014 for nitrogen and total suspended solids), 6 tributaries had decreasing trends in concentrations of total phosphorus, and 12 had increasing trends; concentrations of dissolved phosphorus decreased in 6 and increased in 8 tributaries; fluxes of total phosphorus decreased in 5 and

Crystallization of sheared hard spheres at 64.5% volume fraction

Science.gov (United States)

Swinney, H. L.; Rietz, F.; Schroeter, M.; Radin, C.

2017-11-01

A classic experiment by G.D. Scott Nature 188, 908, 1960) showed that pouring balls into a rigid container filled the volume to an upper limit of 64% of the container volume, which is well below the 74% volume fraction filled by spheres in a hexagonal close packed (HCP) or face center cubic (FCC) lattice. Subsequent experiments have confirmed a ``random closed packed'' (RCP) fraction of about 64%. However, the physics of the RCP limit has remained a mystery. Our experiment on a cubical box filled with 49400 weakly sheared glass spheres reveals a first order phase transition from a disordered to an ordered state at a volume fraction of 64.5%. The ordered state consists of crystallites of mixed FCC and HCP symmetry that coexist with the amorphous bulk. The transition is initiated by homogeneous nucleation: in the shearing process small crystallites with about ten or fewer spheres dissolve, while larger crystallites grow. A movie illustrates the crystallization process. German Academic Exchange Service (DAAD), German Research Foundation (DFG), NSF DMS, and R.A. Welch Foundation.

The toxicity of zinc oxide nanoparticles to Lemna minor (L.) is predominantly caused by dissolved Zn.

Science.gov (United States)

Chen, Xiaolin; O'Halloran, John; Jansen, Marcel A K

2016-05-01

Nano-ZnO particles have been reported to be toxic to many aquatic organisms, although it is debated whether this is caused by nanoparticles per sé, or rather dissolved Zn. This study investigated the role of dissolved Zn in nano-ZnO toxicity to Lemna minor. The technical approach was based on modulating nano-ZnO dissolution by either modifying the pH of the growth medium and/or surface coating of nano-ZnO, and measuring resulting impacts on L. minor growth and physiology. Results show rapid and total dissolution of nano-ZnO in the medium (pH 4.5). Quantitatively similar toxic effects were found when L. minor was exposed to nano-ZnO or the "dissolved Zn equivalent of dissolved nano-ZnO". The conclusion that nano-ZnO toxicity is primarily caused by dissolved Zn was further supported by the observation that phytotoxicity was absent on medium with higher pH-values (>7), where dissolution of nano-ZnO almost ceased. Similarly, the reduced toxicity of coated nano-ZnO, which displays a slower Zn dissolution, is also consistent with a major role for dissolved Zn in nano-ZnO toxicity. Copyright © 2016 Elsevier B.V. All rights reserved.

Use of a dissolved-gas measurement system for reducing the dissolved oxygen at St. Lucie Unit 2

International Nuclear Information System (INIS)

Snyder, D.T.; Coit, R.L.

1993-02-01

When the dissolved oxygen in the condensate at St. Lucie Unit 2 could not be reduced below the administrative limit of 10 ppB, EPRI cooperated with Florida Power and Light to find the cause and develop remedies. Two problems were identified with the assistance of a dissolved gas measurement system (DGMS) that can detect leaks into condensate when used with argon blanketing. Drain piping from the air ejection system had flooded which decreased its performance, and leaks were found at a strainer flange and a couple expansion joints. Initially the dissolved oxygen content was reduced to about 9 ppB; owever, the dissolved oxygen from Condenser A was consistently higher than that from condenser B. Injection of about 0.4 cubic per minute (CFM) of argon above the hotwell considerably improved the ventilation of Condenser A, reducing the dissolved oxygen about 30% to about 6 ppB. The use of nitrogen was equally effective. While inert gas injection is helpful, it may be better to have separate air ejectors for each condenser. Several recommendations for improving oxygen removal are given

Coupling effects of abiotic and biotic factors on molecular composition of dissolved organic matter in a freshwater wetland

Energy Technology Data Exchange (ETDEWEB)

He, Wei [Department of Environment and Energy, Sejong University, Seoul 143-747 (Korea, Republic of); Choi, Ilhwan [Water Analysis and Research Center, K-water, 560 Sintanjin-ro, Daedeok-gu, Daejeon 307-711 (Korea, Republic of); Lee, Jung-Joon [Department of Biological Education, Daegu University, Gyungbuk 712-714 (Korea, Republic of); Hur, Jin, E-mail: jinhur@sejong.ac.kr [Department of Environment and Energy, Sejong University, Seoul 143-747 (Korea, Republic of)

2016-02-15

In this study, temporal and spatial variations in five defined molecular size fractions of dissolved organic matter (DOM) were examined for a well preserved wetland (Upo Wetland) and its surrounding areas, and the influencing factors were explored with many biotic and abioic parameters. For each DOM sample, the five size fractions were determined by size-exclusion chromatography coupled with organic carbon detector (SEC-OCD). For 2-year long monthly monitoring, bio-polymers (BP), humic substances (HS), building blocks (BB), low molecular-weight (LMW) neutrals, and LMW acids displayed the median values of 264, 1884, 1070, 1090, and 11 μg-C L{sup −1}, respectively, accounting for 6.2%, 41.7%, 24.5%, 26.4%, and 0.4% of dissolved organic carbon (DOC). The dominant presence of HS indicated that terrestrial input played important roles in DOM composition of the freshwater ecosystem, which contrasted with coastal wetlands in other reports. Both seasonal and periodic patterns in the variations were found only for HS and BB among the size fractions. It was also notable that the sources of HS were seasonally shifted from aquagenic origin in winter to pedogenic origin in summer. The correlations among the size fractions revealed that BB and LMW neutrals might be degradation products from HS and humic-like substances (HS + BB), respectively, while LMW acids, from LMW neutrals. Principle component analysis revealed that the humic-like substances and the aromaticity of DOM were associated with temperature, chlorophyll a, phosphorous, and rainfall, whereas the other fractions and the molecular weight of HS were primarily affected by solar irradiation. Significant correlations between DOM composition and some biotic factors further suggested that DOM may even affect the biological communities, which provides an insight into the potential coupling effects of biotic and abiotic factors on DOM molecular composition in freshwater wetlands. - Highlights: • Humic fractions varied

Coupling effects of abiotic and biotic factors on molecular composition of dissolved organic matter in a freshwater wetland

International Nuclear Information System (INIS)

He, Wei; Choi, Ilhwan; Lee, Jung-Joon; Hur, Jin

2016-01-01

In this study, temporal and spatial variations in five defined molecular size fractions of dissolved organic matter (DOM) were examined for a well preserved wetland (Upo Wetland) and its surrounding areas, and the influencing factors were explored with many biotic and abioic parameters. For each DOM sample, the five size fractions were determined by size-exclusion chromatography coupled with organic carbon detector (SEC-OCD). For 2-year long monthly monitoring, bio-polymers (BP), humic substances (HS), building blocks (BB), low molecular-weight (LMW) neutrals, and LMW acids displayed the median values of 264, 1884, 1070, 1090, and 11 μg-C L"−"1, respectively, accounting for 6.2%, 41.7%, 24.5%, 26.4%, and 0.4% of dissolved organic carbon (DOC). The dominant presence of HS indicated that terrestrial input played important roles in DOM composition of the freshwater ecosystem, which contrasted with coastal wetlands in other reports. Both seasonal and periodic patterns in the variations were found only for HS and BB among the size fractions. It was also notable that the sources of HS were seasonally shifted from aquagenic origin in winter to pedogenic origin in summer. The correlations among the size fractions revealed that BB and LMW neutrals might be degradation products from HS and humic-like substances (HS + BB), respectively, while LMW acids, from LMW neutrals. Principle component analysis revealed that the humic-like substances and the aromaticity of DOM were associated with temperature, chlorophyll a, phosphorous, and rainfall, whereas the other fractions and the molecular weight of HS were primarily affected by solar irradiation. Significant correlations between DOM composition and some biotic factors further suggested that DOM may even affect the biological communities, which provides an insight into the potential coupling effects of biotic and abiotic factors on DOM molecular composition in freshwater wetlands. - Highlights: • Humic fractions varied

Seasonal and air mass trajectory effects on dissolved organic matter of bulk deposition at a coastal town in south-western Europe.

Science.gov (United States)

Santos, Patrícia S M; Santos, Eduarda B H; Duarte, Armando C

2013-01-01

Rainwater contains a complex mixture of organic compounds which may influence climate, terrestrial and maritime ecosystems and thus human health. In this work, the characteristics of DOM of bulk deposition at a coastal town on the southwest of Europe were assessed by UV-visible and three-dimensional excitation-emission matrix fluorescence spectroscopies and by dissolved organic carbon (DOC) content. The seasonal and air mass trajectory effects on dissolved organic matter (DOM) of bulk deposition were evaluated. The absorbance at 250 nm (UV(250 nm)) and integrated fluorescence showed to be positively correlated with each other, and they were also positively correlated to the DOC in bulk deposition, which suggest that a constant fraction of DOM is likely to fluoresce. There was more chromophoric dissolved organic matter (CDOM) present in summer and autumn seasons than in winter and spring. Bulk deposition associated with terrestrial air masses contained a higher CDOM content than bulk deposition related to marine air masses, thus highlighting the contribution of terrestrial/anthropogenic sources.

Factors associated with pulmonary toxicity after myeloablative conditioning using fractionated total body irradiation

Energy Technology Data Exchange (ETDEWEB)

Byun, Hwa Kyung; Yoon, Hong In; Cho, Jae Ho [Yonsei Cancer Center, Yonsei University College of Medicine, Seoul (Korea, Republic of); and others

2017-09-15

Pulmonary toxicities, including infectious pneumonia (IP) and idiopathic pneumonia syndrome (IPS), are serious side effects of total body irradiation (TBI) used for myeloablative conditioning. This study aimed to evaluate clinical factors associated with IP and IPS following TBI. Fifty-eight patients with hematologic malignancies who underwent TBI before allogeneic hematopoietic stem cell transplantation between 2005 and 2014 were reviewed. Most patients (91%) received 12 Gy in 1.5 Gy fractions twice a day. Pulmonary toxicities were diagnosed based on either radiographic evidence or reduced pulmonary function, and were subdivided into IP and IPS based on the presence or absence of concurrent infection. Pulmonary toxicities developed in 36 patients (62%); 16 (28%) had IP and 20 (34%) had IPS. IP was significantly associated with increased treatment-related mortality (p = 0.028) and decreased survival (p = 0.039). Multivariate analysis revealed that the risk of developing IPS was significantly higher in patients who received stem cells from a matched unrelated donor than from a matched sibling donor (p = 0.021; hazard ratio [HR] = 12.67; 95% confidence interval [CI], 1.46–110.30). Combining other conditioning agents with cyclophosphamide produced a higher tendency to develop IP (p = 0.064; HR = 6.19; 95% CI, 0.90–42.56). IP and IPS involve different risk factors and distinct pathogeneses that should be considered when planning treatments before and after TBI.

Factors associated with pulmonary toxicity after myeloablative conditioning using fractionated total body irradiation

International Nuclear Information System (INIS)

Byun, Hwa Kyung; Yoon, Hong In; Cho, Jae Ho

2017-01-01

Pulmonary toxicities, including infectious pneumonia (IP) and idiopathic pneumonia syndrome (IPS), are serious side effects of total body irradiation (TBI) used for myeloablative conditioning. This study aimed to evaluate clinical factors associated with IP and IPS following TBI. Fifty-eight patients with hematologic malignancies who underwent TBI before allogeneic hematopoietic stem cell transplantation between 2005 and 2014 were reviewed. Most patients (91%) received 12 Gy in 1.5 Gy fractions twice a day. Pulmonary toxicities were diagnosed based on either radiographic evidence or reduced pulmonary function, and were subdivided into IP and IPS based on the presence or absence of concurrent infection. Pulmonary toxicities developed in 36 patients (62%); 16 (28%) had IP and 20 (34%) had IPS. IP was significantly associated with increased treatment-related mortality (p = 0.028) and decreased survival (p = 0.039). Multivariate analysis revealed that the risk of developing IPS was significantly higher in patients who received stem cells from a matched unrelated donor than from a matched sibling donor (p = 0.021; hazard ratio [HR] = 12.67; 95% confidence interval [CI], 1.46–110.30). Combining other conditioning agents with cyclophosphamide produced a higher tendency to develop IP (p = 0.064; HR = 6.19; 95% CI, 0.90–42.56). IP and IPS involve different risk factors and distinct pathogeneses that should be considered when planning treatments before and after TBI

Effect of Different Carbon Substrates on Nitrate Stable Isotope Fractionation During Microbial Denitrification

DEFF Research Database (Denmark)

Wunderlich, Anja; Meckenstock, Rainer; Einsiedl, Florian

2012-01-01

-labeled water and 18O-labeled nitrite were added to the microcosm experiments to study the effect of putative backward reactions of nitrite to nitrate on the stable isotope fractionation. We found no evidence for a reverse reaction. Significant variations of the stable isotope enrichment factor ε were observed......In batch experiments, we studied the isotope fractionation in N and O of dissolved nitrate during dentrification. Denitrifying strains Thauera aromatica and “Aromatoleum aromaticum strain EbN1” were grown under strictly anaerobic conditions with acetate, benzoate, and toluene as carbon sources. 18O...... of nitrate transport across the cell wall compared to the kinetics of the intracellular nitrate reduction step of microbial denitrification....

Adapting IMRT delivery fraction-by-fraction to cater for variable intrafraction motion

International Nuclear Information System (INIS)

Webb, S

2008-01-01

This paper presents a technique for coping with variable intrafraction organ motion when delivering intensity-modulated radiation therapy (IMRT). The strategy is an adaptive delivery in which the fluence delivered up to a particular fraction is subtracted from the required total-course planned fluence to create an adapted residual fluence for the next fraction. This requires that the fluence already delivered can be computed, knowing the intrafraction motion during each fraction. If the adaptation is unconstrained, as would be required for perfect delivery of the planned fluence, then the individual fractional fluences would become unphysical, with both negative components and spikes. Hence it is argued that constraints must be applied; first, positivity constraints and second, constraints to limit fluence spikes. Additionally, it is shown to be helpful to constrain other quantities which are explained. The power of the strategy is that it adapts to the (potentially variable) moving geometry during each fraction. It is not a perfect delivery but it is always better than making no adaptation. The fractionated nature of radiation therapy is thus exploited to advantage. The fluence adaptation method does not require re-planning at each fraction but this imposes limitations which are stated. The fuller theory of dose adaptation is also developed for intrafraction motion. The method is complementary to other adaptive strategies recently discussed with respect to interfraction motion

Size exclusion chromatography with online ICP-MS enables molecular weight fractionation of dissolved phosphorus species in water samples.

Science.gov (United States)

Venkatesan, Arjun K; Gan, Wenhui; Ashani, Harsh; Herckes, Pierre; Westerhoff, Paul

2018-04-15

Phosphorus (P) is an important and often limiting element in terrestrial and aquatic ecosystem. A lack of understanding of its distribution and structures in the environment limits the design of effective P mitigation and recovery approaches. Here we developed a robust method employing size exclusion chromatography (SEC) coupled to an ICP-MS to determine the molecular weight (MW) distribution of P in environmental samples. The most abundant fraction of P varied widely in different environmental samples: (i) orthophosphate was the dominant fraction (93-100%) in one lake, two aerosols and DOC isolate samples, (ii) species of 400-600 Da range were abundant (74-100%) in two surface waters, and (iii) species of 150-350 Da range were abundant in wastewater effluents. SEC-DOC of the aqueous samples using a similar SEC column showed overlapping peaks for the 400-600 Da species in two surface waters, and for >20 kDa species in the effluents, suggesting that these fractions are likely associated with organic matter. The MW resolution and performance of SEC-ICP-MS agreed well with the time integrated results obtained using conventional ultrafiltration method. Results show that SEC in combination with ICP-MS and DOC has the potential to be a powerful and easy-to-use method in identifying unknown fractions of P in the environment. Copyright © 2018 Elsevier Ltd. All rights reserved.

Investigating Marine Dissolved Organic Matter Fluorescence Transformations with Organic Geochemical Proxies in a Growth and Degradation Experiment using Amino Acids, Amino Sugars, and Phenols

Science.gov (United States)

Shields, M. R.; Bianchi, T. S.; Osburn, C. L.; Kinsey, J. D.; Ziervogel, K.; Schnetzer, A.

2017-12-01

The origin and mechanisms driving the formation of fluorescent dissolved organic matter (FDOM) in the open ocean remain unclear. Although recent studies have attempted to deconvolve the chemical composition and source of marine FDOM, these studies have been qualitative in nature. Here, we investigate these transformations using a more quantitative biomarker approach in a controlled growth and degradation experiment. In this experiment, a natural assemblage of phytoplankton was collected off the coast of North Carolina and incubated within roller bottles containing 0.2 µm-filtered North Atlantic surface water amended with f/2 nutrients. Samples were collected at the beginning (day 0), during exponential growth (day 13), stationary (day 20), and degradation (day 62) phases of the phytoplankton incubation. Amino acids, amino sugars, and phenolic compounds of the dissolved (DOM) were measured in conjunction with enzyme assays and bacterial counts to track shifts in OM quality as FDOM formed and was then transformed throughout the experiment. The results from the chemical analyses showed that the OM composition changed significantly from the initial and exponential phases to the stationary and degradation phases of the experiment. The percentage of aromatic amino acids to the total amino acid pool increased significantly during the exponential phase of phytoplankton growth, but then decreased significantly during the stationary and degradation phases. This increase was positively correlated to the fractional contribution of the protein-like peak in fluorescence to the total FDOM fluorescence. An increase in the concentration of amino acid degradation products during the stationary and degradation phases suggests that compositional changes in OM were driven by microbial transformation. This was further supported by a concurrent increase in total enzyme activity and increase in "humic-like" components of the FDOM. These findings link the properties and formation of FDOM

Estimation of Particle Material And Dissolved Flows During Floods In The Inaouene Watershed. (Northeast Of Morocco)

Science.gov (United States)

Sibari, Hayat; Haida, Souad; Foutlane, Mohamed

2018-05-01

This work aims to estimate the contributions of the Inaouene River during the floods. It is in this context that the dissolved and particulate matter flows were measured during the flood periods followed by the 1996/97 study year at the two hydrological stations Bab Marzouka (upstream) and El Kouchat (downstream). The specific flows of dissolved materials calculated upstream and downstream of the Inaouene watershed correspond respectively to 257 t/ km2/year and 117 t/ km2/year. Chlorides represent 30% and 41% respectively of the total dissolved transport upstream and downstream. The potential mechanical degradation affecting the Inaouene watershed can deliver a solid load estimated at 6.106 t/year corresponding to a specific flow of 2142 t/km2/year.

Using fluorescent dissolved organic matter to trace and distinguish the origin of Arctic surface waters

DEFF Research Database (Denmark)

Goncalves-Araujo, Rafael; Granskog, Mats A.; Bracher, Astrid

2016-01-01

were performed in the Fram and Davis Straits, and on the east Greenland Shelf (EGS), in late summer 2012/2013. Meteoric (f(mw)), sea-ice melt, Atlantic and Pacific water fractions were determined and the fluorescence properties of dissolved organic matter (FDOM) were characterized. In Fram Strait...... and EGS, a robust correlation between visible wavelength fluorescence and f(mw) was apparent, suggesting it as a reliable tracer of polar waters. However, a pattern was observed which linked the organic matter characteristics to the origin of polar waters. At depth in Davis Strait, visible wavelength FDOM...

Identification of dissolved-constituent sources in mine-site ground water using batch mixing

Science.gov (United States)

Clark, Gregory M.; Williams, Robert S.

1991-01-01

Batch-mixing experiments were used to help identify lithologic and mineralogic sources of increased concentrations of dissolved solids in water affected by surface coal mining in northwestern Colorado. Ten overburden core samples were analyzed for mineral composition and mixed with distilled water for 90 days until mineral-water equilibrium was reached. Between one day and 90 days after initial contact, specific conductance in the sample mixtures had a median increase of 306 percent. Dissolved-solids concentrations ranged from 200 to 8,700 mg/L in water samples extracted from the mixtures after 90 days. Mass-balance simulations were conducted using the geochemical models BALANCE and WATEQF to quantify mineral-water interactions occurring in five selected sample mixtures and in water collected from a spring at a reclaimed mine site. The spring water is affected by mineral-water interactions occurring in all of the lithologic units comprising the overburden. Results of the simulations indicate that oxidation of pyrite, dissolution of dolomite, gypsum, and epsomite, and cation-exchange reactions are the primary mineral-water interactions occurring in the overburden. Three lithologic units in the overburden (a coal, a sandstone, and a shale) probably contribute most of the dissolved solids to the spring water. Water sample extracts from mixtures using core from these three units accounted for 85 percent of the total dissolved solids in the 10 sample extracts. Other lithologic units in the over-burden probably contribute smaller quantities of dissolved solids to the spring water.

The Foreign Body Giant Cell Cannot Resorb Bone, But Dissolves Hydroxyapatite Like Osteoclasts.

Directory of Open Access Journals (Sweden)

Bas ten Harkel

Full Text Available Foreign body multinucleated giant cells (FBGCs and osteoclasts share several characteristics, like a common myeloid precursor cell, multinuclearity, expression of tartrate-resistant acid phosphatase (TRAcP and dendritic cell-specific transmembrane protein (DC-STAMP. However, there is an important difference: osteoclasts form and reside in the vicinity of bone, while FBGCs form only under pathological conditions or at the surface of foreign materials, like medical implants. Despite similarities, an important distinction between these cell types is that osteoclasts can resorb bone, but it is unknown whether FBGCs are capable of such an activity. To investigate this, we differentiated FBGCs and osteoclasts in vitro from their common CD14+ monocyte precursor cells, using different sets of cytokines. Both cell types were cultured on bovine bone slices and analyzed for typical osteoclast features, such as bone resorption, presence of actin rings, formation of a ruffled border, and characteristic gene expression over time. Additionally, both cell types were cultured on a biomimetic hydroxyapatite coating to discriminate between bone resorption and mineral dissolution independent of organic matrix proteolysis. Both cell types differentiated into multinucleated cells on bone, but FBGCs were larger and had a higher number of nuclei compared to osteoclasts. FBGCs were not able to resorb bone, yet they were able to dissolve the mineral fraction of bone at the surface. Remarkably, FBGCs also expressed actin rings, podosome belts and sealing zones--cytoskeletal organization that is considered to be osteoclast-specific. However, they did not form a ruffled border. At the gene expression level, FBGCs and osteoclasts expressed similar levels of mRNAs that are associated with the dissolution of mineral (e.g., anion exchange protein 2 (AE2, carbonic anhydrase 2 (CAII, chloride channel 7 (CIC7, and vacuolar-type H+-ATPase (v-ATPase, in contrast the matrix degrading

Linking CDOM spectral absorption to dissolved organic carbon concentrations and loadings in boreal estuaries

DEFF Research Database (Denmark)

Asmala, Eero; Stedmon, Colin A.; Thomas, David N.

2012-01-01

concentrations across the salinity gradient and ranged from 1.67 to 33.4 m−1. The link between DOC and CDOM was studied using a range of wavelengths and algorithms. Wavelengths between 250 and 270 nm gave the best predictions with single linear regression. Total dissolved iron was found to influence......The quantity of chromophoric dissolved organic matter (CDOM) and dissolved organic carbon (DOC) in three Finnish estuaries (Karjaanjoki, Kyrönjoki and Kiiminkijoki) was investigated, with respect to predicting DOC concentrations and loadings from spectral CDOM absorption measurements. Altogether 87...... the prediction in wavelengths above 520nm. Despite significant seasonal and spatial differences in DOC–CDOM models, a universal relationship was tested with an independent data set and found to be robust. DOC and CDOM yields (loading/catchment area) from the catchments ranged from 1.98 to 5.44gCm−2yr−1, and 1...

Fouling Characteristics of Dissolved Organic Matter in Papermaking Process Water on Polyethersulfone Ultrafiltration Membranes

Directory of Open Access Journals (Sweden)

Wenpeng Su

2015-07-01

Full Text Available In the papermaking industry, closure of process water (whitewater circuits has been used to reduce fresh water consumption. Membrane separation technology has potential for use in treating process water for recirculation. The purpose of this study was to reveal the fouling characteristics of a polyethersulfone (PES ultrafiltration membrane caused by dissolved organic matter (DOM in process water. Ultrafiltration membranes (UF and DAX ion exchange resins were applied to characterize the molecular weight (MW and hydrophilicity distribution of DOM. The interactions between various fractions of DOM and a PES ultrafiltration membrane were investigated. The membrane fouling characteristics were elucidated by examining the filtration resistances and linearized Herman’s blocking models. The results demonstrated that the membrane was fouled significantly by much of the MW distribution. The membrane was fouled more significantly by the low MW fraction rather than the high MW fraction. The filtration resistances and the fitted equation of Hermia’s laws indicated that hydrophilic organics were the main foulants. The hydrophilic organics partially block the membrane pores and form intermediate blocking, reducing the effective filtration area, while the hydrophobic organics form a gel layer or cake on the surface of the membrane.

DISSOLVED CONCENTRATION LIMITS OF RADIOACTIVE ELEMENTS

Energy Technology Data Exchange (ETDEWEB)

NA

2004-11-22

The purpose of this study is to evaluate dissolved concentration limits (also referred to as solubility limits) of elements with radioactive isotopes under probable repository conditions, based on geochemical modeling calculations using geochemical modeling tools, thermodynamic databases, field measurements, and laboratory experiments. The scope of this modeling activity is to predict dissolved concentrations or solubility limits for 14 elements with radioactive isotopes (actinium, americium, carbon, cesium, iodine, lead, neptunium, plutonium, protactinium, radium, strontium, technetium, thorium, and uranium) important to calculated dose. Model outputs for uranium, plutonium, neptunium, thorium, americium, and protactinium are in the form of tabulated functions with pH and log (line integral) CO{sub 2} as independent variables, plus one or more uncertainty terms. The solubility limits for the remaining elements are either in the form of distributions or single values. The output data from this report are fundamental inputs for Total System Performance Assessment for the License Application (TSPA-LA) to determine the estimated release of these elements from waste packages and the engineered barrier system. Consistent modeling approaches and environmental conditions were used to develop solubility models for all of the actinides. These models cover broad ranges of environmental conditions so that they are applicable to both waste packages and the invert. Uncertainties from thermodynamic data, water chemistry, temperature variation, and activity coefficients have been quantified or otherwise addressed.

The dependence of radiation response on the dose per fraction

International Nuclear Information System (INIS)

Joiner, M.C.

1989-01-01

The linear-quadratic (LQ) model explains the dependence of total dose in a fractionated course on the dose per fraction, in a very wide range of tumour and normal tissue studies, providing the dose per fraction remains above 2 Gy. In the range 2-1 Gy per fraction, some experimental studies show less increase in total dose than predicted by LQ; a probable explanation is incomplete repair between fractions given 2 seen between 1 and 0.1 Gy per fraction. This cannot be explained by incomplete repair; a modified LQ model where α decreases sharply with increasing dose per fraction in the range 0-1 Gy fits these data. The basic LQ model describes data from neutron fractionation studies, so the relationship between relative biological effectiveness (RBE) and X-ray dose per fraction can be expressed in terms of LQ parameters and fitted directly to RBE data. Results from different experiments, different assays and both top-up and full-course fractionation techniques, can all be included in one analysis. (author)

Controls on stream water dissolved mercury in three mid-Appalachian forested headwater catchments

Science.gov (United States)

Riscassi, Ami L.; Scanlon, Todd M.

2011-12-01

Determining the controls on dissolved mercury (HgD) transport is necessary to improve estimations of export from unmonitored watersheds and to forecast responses to changes in deposition and other environmental forcings. Stream water HgD and dissolved organic carbon (DOC) were evaluated over a range of discharge conditions in three streams within Shenandoah National Park, VA. Watersheds are distinguished by stream water pH (ranging from neutral to acidic) and soil size fractioning (ranging from clays to sands). At all sites, discharge was a significant but poor predictor of HgD concentrations (r2 from 0.13-0.52). HgD was strongly coupled with DOC at all sites (r2 from 0.74-0.89). UV absorbance at 254 nm (UV254), a proxy for DOC quantity and quality, slightly improved the predictions of HgD. Mean DOC quality differed between streams, with less aromatic DOC mobilized from the more acidic watershed. The site with less aromatic DOC and sandy soils mobilized more Hg to the stream for the same quantity and quality of DOC, likely due to the reduced capacity of the larger-grained soils to retain Hg, leaving a greater fraction associated with the organic matter. A similar amount of 0.54 ng HgD/mg DOC is transported at all sites, suggesting the less aromatic DOC transports less Hg per unit DOC, offsetting the effects of soil type. This research demonstrates that soil composition and DOC quality influence HgDexport. We also provide evidence that soil organic carbon is a primary control on Hg-DOC ratios (0.12-1.4 ng mg-1) observed across the U.S. and Sweden.

Speciation of copper and zinc in size-fractionated atmospheric particulate matter using total reflection mode X-ray absorption near-edge structure spectrometry

International Nuclear Information System (INIS)

Osan, Janos; Meirer, Florian; Groma, Veronika; Toeroek, Szabina; Ingerle, Dieter; Streli, Christina; Pepponi, Giancarlo

2010-01-01

The health effects of aerosol depend on the size distribution and the chemical composition of the particles. Heavy metals of anthropogenic origin are bound to the fine aerosol fraction (PM 2.5 ). The composition and speciation of aerosol particles can be variable in time, due to the time-dependence of anthropogenic sources as well as meteorological conditions. Synchrotron-radiation total reflection X-ray fluorescence (SR-TXRF) provides very high sensitivity for characterization of atmospheric particulate matter. X-ray absorption near-edge structure (XANES) spectrometry in conjunction with TXRF detection can deliver speciation information on heavy metals in aerosol particles collected directly on the reflector surface. The suitability of TXRF-XANES for copper and zinc speciation in size-fractionated atmospheric particulate matter from a short sampling period is presented. For high size resolution analysis, atmospheric aerosol particles were collected at different urban and rural locations using a 7-stage May cascade impactor having adapted for sampling on Si wafers. The thin stripe geometry formed by the particulate matter deposited on the May-impactor plates is ideally suited to SR-TXRF. Capabilities of the combination of the May-impactor sampling and TXRF-XANES measurements at HASYLAB Beamline L to Cu and Zn speciation in size-fractionated atmospheric particulate matter are demonstrated. Information on Cu and Zn speciation could be performed for elemental concentrations as low as 140 pg/m 3 . The Cu and Zn speciation in the different size fraction was found to be very distinctive for samples of different origin. Zn and Cu chemical state typical for soils was detected only in the largest particles studied (2-4 μm fraction). The fine particles, however, contained the metals of interest in the sulfate and nitrate forms.

Effects of different water storage procedures on the dissolved Fe concentration and isotopic composition of chemically contrasted waters from the Amazon River Basin.

Science.gov (United States)

Mulholland, Daniel S; Poitrasson, Franck; Boaventura, Geraldo R

2015-11-15

Although recent studies have investigated the Fe isotopic composition of dissolved, colloidal and particulate phases from continental and oceanic natural waters, few efforts have been made to evaluate whether water sample storage and the separation of different pore-size fractions through filtration can cause any change to the Fe isotopic compositions. The present study investigates the possible biases introduced by different water storage conditions on the dissolved Fe concentration and isotopic composition of chemically different waters. Water samples were collected from an organic-rich river and from mineral particulate-rich rivers. Filtered and unfiltered water samples were stored either at room temperature or frozen at -18°C in order to assess possible biases due to (i) different water storage temperature, and (ii) storage of bulk (unfiltered) vs filtered water. Iron isotope measurements were performed by Multicollector Inductively Coupled Plasma Mass Spectrometry with a Thermo Electron Neptune instrument, after Fe purification using anion-exchange resins. Our data reveal that bulk water storage at room temperature without filtration produces minor changes in the dissolved Fe isotopic composition of mineral particulate-rich waters, but significant isotopic composition changes in organic-rich waters. In both cases, however, the impact of the different procedures on the Fe concentrations was strong. On the other hand, the bulk water stored frozen without filtration produced more limited changes in the dissolved Fe concentrations, and also on isotopic compositions, relative to the samples filtered in the field. The largest effect was again observed for the organic-rich waters. These findings suggest that a time lag between water collection and filtration may cause isotopic exchanges between the dissolved and particulate Fe fractions. When it is not possible to filter the samples in the field immediately after collection, the less detrimental approach is to

Influence of dissolved organic matter and manganese oxides on metal speciation in soil solution: A modelling approach.

Science.gov (United States)

Schneider, Arnaud R; Ponthieu, Marie; Cancès, Benjamin; Conreux, Alexandra; Morvan, Xavier; Gommeaux, Maxime; Marin, Béatrice; Benedetti, Marc F

2016-06-01

Trace element (TE) speciation modelling in soil solution is controlled by the assumptions made about the soil solution composition. To evaluate this influence, different assumptions using Visual MINTEQ were tested and compared to measurements of free TE concentrations. The soil column Donnan membrane technique (SC-DMT) was used to estimate the free TE (Cd, Cu, Ni, Pb and Zn) concentrations in six acidic soil solutions. A batch technique using DAX-8 resin was used to fractionate the dissolved organic matter (DOM) into four fractions: humic acids (HA), fulvic acids (FA), hydrophilic acids (Hy) and hydrophobic neutral organic matter (HON). To model TE speciation, particular attention was focused on the hydrous manganese oxides (HMO) and the Hy fraction, ligands not considered in most of the TE speciation modelling studies in soil solution. In this work, the model predictions of free ion activities agree with the experimental results. The knowledge of the FA fraction seems to be very useful, especially in the case of high DOM content, for more accurately representing experimental data. Finally, the role of the manganese oxides and of the Hy fraction on TE speciation was identified and, depending on the physicochemical conditions of the soil solution, should be considered in future studies. Copyright © 2016 Elsevier Ltd. All rights reserved.

Fractional rate of degradation (kd) of starch in the rumen and its relation to in vivo rumen and total digestibility

DEFF Research Database (Denmark)

Hvelplund, Torben; Larsen, Mogens; Lund, Peter

2009-01-01

in different ways both chemically and physically. The starch sources were fed in mixed diets together with grass silage and soya bean meal and allocated ad libitum to fistulated dairy cows. The starch content varied between 13 and 35% in ration dry matter for the different starch sources. The design...... was a series of cross-over experiments with two cows and two periods. Ruminal starch pool was estimated from rumen evacuation and starch flow was estimated by duodenal and faeces sampling. Fractional rate of rumen degradation was estimated from the equation [kd = rumen degraded/rumen pool] and rumen and total...

Size fractionation of waste-to-energy boiler ash enables separation of a coarse fraction with low dioxin concentrations.

Science.gov (United States)

Weidemann, E; Allegrini, E; Fruergaard Astrup, T; Hulgaard, T; Riber, C; Jansson, S

2016-03-01

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) formed in modern Waste-to-Energy plants are primarily found in the generated ashes and air pollution control residues, which are usually disposed of as hazardous waste. The objective of this study was to explore the occurrence of PCDD/F in different grain size fractions in the boiler ash, i.e. ash originating from the convection pass of the boiler. If a correlation between particle size and dioxin concentrations could be found, size fractionation of the ashes could reduce the total amount of hazardous waste. Boiler ash samples from ten sections of a boiler's convective part were collected over three sampling days, sieved into three different size fractions - 0.355 mm - and analysed for PCDD/F. The coarse fraction (>0.355 mm) in the first sections of the horizontal convection pass appeared to be of low toxicity with respect to dioxin content. While the total mass of the coarse fraction in this boiler was relatively small, sieving could reduce the amount of ash containing toxic PCDD/F by around 0.5 kg per tonne input waste or around 15% of the collected boiler ash from the convection pass. The mid-size fraction in this study covered a wide size range (0.09-0.355 mm) and possibly a low toxicity fraction could be identified by splitting this fraction into more narrow size ranges. The ashes exhibited uniform PCDD/F homologue patterns which suggests a stable and continuous generation of PCDD/F. Copyright © 2016 Elsevier Ltd. All rights reserved.

Process for the production of protein enriched fractions from vegetable materials

NARCIS (Netherlands)

Dijkink, B.H.; Willemsen, J.H.A.

2006-01-01

The present invention provides a method for the production of a protein enriched fraction and a fibre enriched fraction from a vegetable material, wherein the vegetable material comprises a total fat content of 0.1 to 22.0 % by dry weight of the total vegetable material and a total starch content of

Cellulase activity and dissolved organic carbon release from lignocellulose macrophyte-derived in four trophic conditions

Directory of Open Access Journals (Sweden)

Flávia Bottino

2016-06-01

Full Text Available Abstract Considering the importance of lignocellulose macrophyte-derived for the energy flux in aquatic ecosystems and the nutrient concentrations as a function of force which influences the decomposition process, this study aims to relate the enzymatic activity and lignocellulose hydrolysis in different trophic statuses. Water samples and two macrophyte species were collected from the littoral zone of a subtropical Brazilian Reservoir. A lignocellulosic matrix was obtained using aqueous extraction of dried plant material (≈40 °C. Incubations for decomposition of the lignocellulosic matrix were prepared using lignocelluloses, inoculums and filtered water simulating different trophic statuses with the same N:P ratio. The particulate organic carbon and dissolved organic carbon (POC and DOC, respectively were quantified, the cellulase enzymatic activity was measured by releasing reducing sugars and immobilized carbon was analyzed by filtration. During the cellulose degradation indicated by the cellulase activity, the dissolved organic carbon daily rate and enzyme activity increased. It was related to a fast hydrolysable fraction of cellulose that contributed to short-term carbon immobilization (ca. 10 days. After approximately 20 days, the dissolved organic carbon and enzyme activity were inversely correlated suggesting that the respiration of microorganisms was responsible for carbon mineralization. Cellulose was an important resource in low nutrient conditions (oligotrophic. However, the detritus quality played a major role in the lignocelluloses degradation (i.e., enzyme activity and carbon release.

Millstone 3 condensate dissolved gas monitoring

International Nuclear Information System (INIS)

Burns, T.F.; Grondahl, E.E.; Snyder, D.T.

1988-01-01

Condensate dissolved oxygen problems at Millstone Point Unit 3 (MP3) were investigated using the Dissolved Gas Monitoring System developed by Radiological and Chemical Technology, Inc. under EPRI sponsorship. Argon was injected into the turbine exhaust basket tips to perform a dissolved gas transport analysis and determine steam jet air ejector gas removal efficiency. The operating configuration of the steam jet air ejector system was varied to determine the effect on gas removal efficiency. Following circulating water chlorination, the gas removal efficiency was determined to evaluate the effect of condenser tube fouling on steam jet air ejector performance

Particle phase distribution of polycyclic aromatic hydrocarbons in stormwater — Using humic acid and iron nano-sized colloids as test particles

DEFF Research Database (Denmark)

Nielsen, Katrine; Kalmykova, Yuliya; Strömvall, Ann-Margret

2015-01-01

The distribution of polycyclic aromatic hydrocarbons (PAHs) in different particulate fractions in stormwater: Total, Particulate, Filtrated, Colloidal and Dissolved fractions, were examined and compared to synthetic suspensions of humic acid colloids and iron nano-sized particles. The distribution...

Dissolved oxygen detection by galvanic displacement-induced

Indian Academy of Sciences (India)

Dissolved oxygen detection by galvanic displacement-induced graphene/silver nanocomposite ... dissolved oxygen (DO) detection based on a galvanic displacement synthesized reduced graphene oxide–silver nanoparticles ... Current Issue

Effectivity of Beta vulgaris L. Extract with various Solvent Fractions to Aedes aegypti Larval Mortality

Directory of Open Access Journals (Sweden)

Mutiara Widawati

2013-06-01

Full Text Available Dengue vector control is mostly done by using plant-based insecticides. Insecticides from the vegetable and fruit extracts of the leaves of plants that contain compounds alkaloids, saponins, flavonoids, tannins, triterpenoids, and polyphenols can be used as an alternative to naturally control Ae. aegypti. The purpose of this study was to determine the effectiveness of the B. vulgaris L. extract larvacide against larvae of Ae. aegypti. The materials that been used was B. vulgaris L. fruit parts which was milled and dried to become a powder form. 800 g of dry powder was extracted by 70% methanol by percolation method with occasional stirring for 3 days. The extract was concentrated using an evaporator. 60 g remaining residue was dissolved in distilled water and re-extracted with diethyl ether, chloroform, and ethyl acetate. Each fraction extract was dried with anhydrous sodium sulfate and the solvent was distilled. The extract was tested qualitatively to determine the content of secondary metabolites. Larvacide test performed by dissolving each extracts in dimetilsulphoxide (DMSO at concentrations of 0.1, 0.5 and 1%. The larvae used was larval of Ae. aegypti age of seven days. Death larvae counted every day for seven days to determine the effect of the contact. Tests carried out at a temperature of 27±1°C by immersing 25 larvae at each concentration of the extract with 50 mL volume and three replications was performed. The data obtained were analyzed further with different test. The results showed that fruit extract contains flavonoids, alkoloid, sterols, triterpenes, saponins and tannins. Highest mortality happened which was 82.5% and the lowest mortality happened with a concentration of 0.1% diethyl ether extract fraction. The extracts that are dissolved in various solvent fractions have not been effective as a larvacide until the highest concentration which was 1%. Methanol and polar solvent extracts of the fruit has a larvacide potency a bit

Dissolved organic matter composition drives the marine production of brominated very short-lived substances.

Science.gov (United States)

Liu, Yina; Thornton, Daniel C O; Bianchi, Thomas S; Arnold, William A; Shields, Michael R; Chen, Jie; Yvon-Lewis, Shari A

2015-03-17

Brominated very short-lived substances (BrVSLS), such as bromoform, are important trace gases for stratospheric ozone chemistry. These naturally derived trace gases are formed via bromoperoxidase-mediated halogenation of dissolved organic matter (DOM) in seawater. Information on DOM type in relation to the observed BrVSLS concentrations in seawater, however, is scarce. We examined the sensitivity of BrVSLS production in relation to the presence of specific DOM moieties. A total of 28 model DOM compounds in artificial seawater were treated with vanadium bromoperoxidase (V-BrPO). Our results show a clear dependence of BrVSLS production on DOM type. In general, molecules that comprise a large fraction of the bulk DOM pool did not noticeably affect BrVSLS production. Only specific cell metabolites and humic acid appeared to significantly enhance BrVSLS production. Amino acids and lignin phenols suppressed enzyme-mediated BrVSLS production and may instead have formed halogenated nonvolatile molecules. Dibromomethane production was not observed in any experiments, suggesting it is not produced by the same pathway as the other BrVSLS. Our results suggest that regional differences in DOM composition may explain the observed BrVSLS concentration variability in the global ocean. Ultimately, BrVSLS production and concentrations are likely affected by DOM composition, reactivity, and cycling in the ocean.

Mathematical modeling of dissolved oxygen in fish ponds ...

African Journals Online (AJOL)

Mathematical modeling of dissolved oxygen in fish ponds. WJS Mwegoha, ME Kaseva, SMM Sabai. Abstract. A mathematical model was developed to predict the effects of wind speed, light, pH, Temperature, dissolved carbon dioxide and chemical oxygen demand (COD) on Dissolved Oxygen (DO) in fish ponds. The effects ...

Utilizing chromophoric dissolved organic matter measurements to derive export and reactivity of dissolved organic carbon exported to the Arctic Ocean: A case study of the Yukon River, Alaska

Science.gov (United States)

Spencer, R.G.M.; Aiken, G.R.; Butler, K.D.; Dornblaser, M.M.; Striegl, Robert G.; Hernes, P.J.

2009-01-01

The quality and quantity of dissolved organic matter (DOM) exported by Arctic rivers is known to vary with hydrology and this exported material plays a fundamental role in the biogeochemical cycling of carbon at high latitudes. We highlight the potential of optical measurements to examine DOM quality across the hydrograph in Arctic rivers. Furthermore, we establish chromophoric DOM (CDOM) relationships to dissolved organic carbon (DOC) and lignin phenols in the Yukon River and model DOC and lignin loads from CDOM measurements, the former in excellent agreement with long-term DOC monitoring data. Intensive sampling across the historically under-sampled spring flush period highlights the importance of this time for total export of DOC and particularly lignin. Calculated riverine DOC loads to the Arctic Ocean show an increase from previous estimates, especially when new higher discharge data are incorporated. Increased DOC loads indicate decreased residence times for terrigenous DOM in the Arctic Ocean with important implications for the reactivity and export of this material to the Atlantic Ocean. Citation: Spencer, R. G. M., G. R. Aiken, K. D. Butler, M. M. Dornblaser, R. G. Striegl, and P. J. Hernes (2009), Utilizing chromophoric dissolved organic matter measurements to derive export and reactivity of dissolved organic carbon exported to the Arctic Ocean: A case study of the Yukon River, Alaska, Geophys. Res. Lett., 36, L06401, doi:10.1029/ 2008GL036831. Copyright 2009 by the American Geophysical Union.

Spatiotemporal characterization of dissolved carbon for inland waters in semi-humid/semiarid region, China

Science.gov (United States)

Song, K. S.; Zang, S. Y.; Zhao, Y.; Du, J.; Li, L.; Zhang, N. N.; Wang, X. D.; Shao, T. T.; Guan, Y.; Liu, L.

2013-05-01

Spatiotemporal variations of dissolved organic carbon (DOC), inorganic carbon (DIC) in 26 waters across the semi-humid/semi-arid Songnen Plain, China were examined with data collected during 2008-2011. Fresh (n = 14) and brackish (n = 12) waters were grouped according to electrical conductivity (threshold = 1000 μS cm-1). Significant differences in the mean DOC/DIC concentrations were observed between fresh (5.63 mg L-1, 37.39 mg L-1) and brackish waters (15.33 mg L-1, 142.93 mg L-1). Colored dissolved organic matter (CDOM) and DOC concentrations were mainly controlled by climatic-hydrologic conditions. The observation indicated that the outflow conditions in the semi-endorheic region had condensed effects on the dissolved carbon, resulting in close relationships between salinity vs. DOC (R2 = 0.66), and vs. DIC (R2 = 0.94). Independent data set collected in May 2012 also confirmed this finding (DOC: R2 = 0.79), (DIC: R2 = 0.91), highlighting the potential of quantifying DOC/DIC via salinity measurements for waters dispersed in the plain. Indices based on CDOM absorption spectra, e.g. DOC specific CDOM absorption (SUVA254), absorption ratio a250 : a365 (E250:365) and spectral slope ratio (Sr, S275-295/S350-400), were applied to characterize DOM composition and quality. Our results indicate high molecular weight CDOM fractions are more abundant in fresh waters than brackish waters.

Dissolved inorganic carbon, total alkalinity, nutrients, and other variables collected from profile and discrete observations using Niskin bottle and other instruments from NOAA Ship Henry B. Bigelow in Gulf of Maine, Georges Bank, and Mid-Atlantic Bight from 2015-05-20 to 2015-06-02 (NCEI Accession 0157024)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains profile discrete measurements of dissolved inorganic carbon, total alkalinity, nutrients, and chlorophyll a in Mid-Atlantic Bight and...

The Evolution of Deepwater Dissolved Oxygen in the Northern South China Sea During the Past 400 ka

Science.gov (United States)

Wang, N.; Huang, B.; Dong, Y.

2016-12-01

Reconstruction of dissolved oxygen in paleo-ocean contributes toward understanding the history of ocean circulation, climate, causes of extinctions, and the evolution of marine organisms. Based on analysis of benthic foraminifera oxygen index (BFOI), the redox-sensitive trace elements (Mo/Al), the percentage of epifaunal benthic foraminifera and infaunal/epifaunal ratio at core MD12-3432, we reconstruct the evolution of deep water dissolved oxygen in northern South China Sea (SCS) during the past 400 ka and discuss the mechanisms of variable dissolved oxygen. Both BFOI and Mo/Al are redox indicators. Similar trends confirm that they reflect the variation of dissolved oxygen in seawater since 400 ka accurately. BFOI and Mo/Al indicate that dissolved oxygen was high in MIS 11-MIS 7 and decreased gradually during MIS 6- MIS 2. The percentage of epifauna decreased and infaunal/epifaunal ratio increased with decreasing dissolved oxygen. By comparison of dissolved oxygen and productivity indexes such as phytoplankton total (PT) and species abundances, we found that when PT fluctuated in the average range of 1000-1500 ng/g, the abundances of Bulimina and Uvigerina which represent high productivity increased. However, when PT reached the range of 2500-3000 ng/g, the abundances of Bulimina and Uvigerina didn't increase, but the abundances of dysoxic species Chilostomella oolina and Globobulimina pacifica increased and the dissolved oxygen reached low value. The reasons may be that the decomposition of excessive organic matter consumed more dissolved oxygen. The low dissolved oxygen suppressed the growth of Bulimina and Uvigerina and accelerated the boom of C. oolina and G. oolina. The dissolved oxygen is not only associated with productivity, but also affected by the thermohaline circulation. Benthic foraminifera F. favus is the representative species in Pacific deep water. Its appearance at 194 ka, 205 ka, 325, the 328 ka in MD12-3432 indicate that the upper border of

Factorial analysis of the trihalomethane formation in the reaction of colloidal, hydrophobic, and transphilic fractions of DOM with free chlorine.

Science.gov (United States)

Platikanov, Stefan; Tauler, Roma; Rodrigues, Pedro M S M; Antunes, Maria Cristina G; Pereira, Dilson; Esteves da Silva, Joaquim C G

2010-09-01

This study focuses on the factors that affect trihalomethane (THMs) formation when dissolved organic matter (DOM) fractions (colloidal, hydrophobic, and transphilic fractions) in aqueous solutions were disinfected with chlorine. DOM fractions were isolated and fractionated from filtered lake water and were characterized by elemental analysis. The investigation involved a screening Placket-Burman factorial analysis design of five factors (DOM concentration, chlorine dose, temperature, pH, and bromide concentration) and a Box-Behnken design for a detailed assessment of the three most important factor effects (DOM concentration, chlorine dose, and temperature). The results showed that colloidal fraction has a relatively low contribution to THM formation; transphilic fraction was responsible for about 50% of the chloroform generation, and the hydrophobic fraction was the most important to the brominated THM formation. When colloidal and hydrophobic fraction solutions were disinfected, the most significant factors were the following: higher DOM fraction concentration led to higher THM concentration, an increase of pH corresponded to higher concentration levels of chloroform and reduced bromoform, higher levels of chlorine dose and temperature produced a rise in the total THM formation, especially of the chlorinated THMs; higher bromide concentration generates higher concentrations of brominated THMs. Moreover, linear models were implemented and response surface plots were obtained for the four THM concentrations and their total sum in the disinfection solution as a function of the DOM concentration, chlorine dose, and temperature. Overall, results indicated that THM formation models were very complex due to individual factor effects and significant interactions among the factors. In order to reduce the concentration of THMs in drinking water, DOM concentrations must be reduced in the water prior to the disinfection. Fractionation of DOM, together with an elemental

Factors influencing the dissolved iron input by river water to the open ocean

Science.gov (United States)

Krachler, R.; Jirsa, F.; Ayromlou, S.

2005-05-01

The influence of natural metal chelators on the bio-available iron input to the ocean by river water was studied. Ferrous and ferric ions present as suspended colloidal particles maintaining the semblance of a dissolved load are coagulated and settled as their freshwater carrier is mixed with seawater at the continental boundary. However, we might argue that different iron-binding colloids become sequentially destabilized in meeting progressively increasing salinities. By use of a 59Fe tracer method, the partitioning of the iron load from the suspended and dissolved mobile fraction to storage in the sediments was measured with high accuracy in mixtures of natural river water with artificial sea water. The results show a characteristic sequence of sedimentation. Various colloids of different stability are removed from a water of increasing salinity, such as it is the case in the transition from a river water to the open sea. However, the iron transport capacities of the investigated river waters differed greatly. A mountainous river in the Austrian Alps would add only about 5% of its dissolved Fe load, that is about 2.0 µg L-1 Fe, to coastal waters. A small tributary draining a sphagnum peat-bog, which acts as a source of refractory low-molecular-weight fulvic acids to the river water, would add approximately 20% of its original Fe load, that is up to 480 µg L-1 Fe to the ocean's bio-available iron pool. This points to a natural mechanism of ocean iron fertilization by terrigenous fulvic-iron complexes originating from weathering processes occurring in the soils upstream.

The one-sample PARAFAC approach reveals molecular size distributions of fluorescent components in dissolved organic matter

DEFF Research Database (Denmark)

Wünsch, Urban; Murphy, Kathleen R.; Stedmon, Colin

2017-01-01

Molecular size plays an important role in dissolved organic matter (DOM) biogeochemistry, but its relationship with the fluorescent fraction of DOM (FDOM) remains poorly resolved. Here high-performance size exclusion chromatography (HPSEC) was coupled to fluorescence emission-excitation (EEM...... but not their spectral properties. Thus, in contrast to absorption measurements, bulk fluorescence is unlikely to reliably indicate the average molecular size of DOM. The one-sample approach enables robust and independent cross-site comparisons without large-scale sampling efforts and introduces new analytical...... opportunities for elucidating the origins and biogeochemical properties of FDOM...

In-situ measurement of the dissolved S2- in seafloor diffuse flow system: sensor preparation and calibration

Institute of Scientific and Technical Information of China (English)

Ying YE; Xia HUANG; Yi-wen PAN; Chen-hua HAN; Wei ZHAO

2008-01-01

The preparation approach and calibration result of an improved type of ion selective electrode (ISE), which is used to measure the total dissolved S2-, are introduced in this paper. The improved Ag/Ag2S electrode uses silver wire as the substrate, which is surrounded by electric polymer containing superfine silver powder. After the stabilization of the epoxy-resin, Ag2ES layer was formed by chemical reaction with 0.2 mol/L (NH4)2S solution for 5 min. With Ag/AgCl as reference electrode, the Ag/Ag2S electrode can be used to measure dissolved S2-. The correlation between the measured potentials and the logarithm of dissolved S2- is found to be linear, within range of the concentration of dissolved S2- from 10-2～10-7 mol/L. The slope of the regression line between measured potential and logarithm of dissolved S2- is about -27.7, which agrees well with the theoretical Nernst value -29.6. Furthermore, the performance of the improved Ag/Ag2S electrode, such as the response time, sensitivity and stability, greatly outweighs the conventional Ag/Ag2S electrode.

Analysis of a slow-dissolving medicine by EPMA

International Nuclear Information System (INIS)

Sasayama, Tetsuaki; Kohara, Kiyohiro; Araki, Takeshi

1995-01-01

Along with a dissolution test of a slow-dissolving medicine, the change in distribution of the drug in solution can be observed by using EPMA, and the structual factors and dissolution mechanism which determine the bioavailability of medicine can be clarified. In the evaluation of physical, chemical and pharmaceutical qualities, it is concluded that EPMA is very effective in elemental and state analyses with observation of microscopic areas on the micrometer order. Especially, the color mapping method clarifies the distribution of a drug in the total image field and enables us to analyze the mechanism of a dissolution medicine. (author)

Dissolved and colloidal trace elements in the Mississippi River Delta outflow after Hurricanes Katrina and Rita

Science.gov (United States)

Shim, Moo-Joon; Swarzenski, Peter W.; Shiller, Alan M.

2012-01-01

The Mississippi River delta outflow region is periodically disturbed by tropical weather systems including major hurricanes, which can terminate seasonal bottom water hypoxia and cause the resuspension of shelf bottom sediments which could result in the injection of trace elements into the water column. In the summer of 2005, Hurricanes Katrina and Rita passed over the Louisiana Shelf within a month of each other. Three weeks after Rita, we collected water samples in the Mississippi River delta outflow, examining the distributions of trace elements to study the effect of Hurricanes Katrina and Rita. We observed limited stratification on the shelf and bottom waters that were no longer hypoxic. This resulted, for instance, in bottom water dissolved Mn being lower than is typically observed during hypoxia, but with concentrations still compatible with Mn–O2 trends previously reported. Interestingly, for no element were we able to identify an obvious effect of sediment resuspension on its distribution. In general, elemental distributions were compatible with previous observations in the Mississippi outflow system. Co and Re, which have not been reported for this system previously, showed behavior consistent with other systems: input for Co likely from desorption and conservative mixing for Re. For Cs, an element for which there is little information regarding its estuarine behavior, conservative mixing was also observed. Our filtration method, which allowed us to distinguish the dissolved (<0.02 μm) from colloidal (0.02–0.45 μm) phase, revealed significant colloidal fractions for Fe and Zn, only. For Fe, the colloidal phase was the dominant fraction and was rapidly removed at low salinity. Dissolved Fe, in contrast, persisted out to mid-salinities, being removed in a similar fashion to nitrate. This ability to distinguish the smaller Fe (likely dominantly organically complexed) from larger colloidal suspensates may be useful in better interpreting the

Determination of total antioxidant capacity of milk by CUPRAC and ABTS methods with separate characterisation of milk protein fractions.

Science.gov (United States)

Çekiç, Sema Demirci; Demir, Aslı; Başkan, Kevser Sözgen; Tütem, Esma; Apak, Reşat

2015-05-01

Most milk-applied antioxidant assays in literature are based on the isolation and quantification of individual antioxidative compounds, whereas total antioxidant capacity (TAC) gives a more holistic picture due to cooperative action of antioxidants. Recently, the cupric reducing antioxidant capacity (CUPRAC) method has been modified to measure the antioxidant capacities of thiol-containing proteins, where the classical ammonium acetate buffer - that may otherwise precipitate proteins- was replaced with concentrated urea buffer (able to expose embedded thiol groups of proteins to oxidative attack) adjusted to pH 7.0. Thus, antioxidant capacity of milk was investigated with two competing TAC assays, namely CUPRAC and ABTS (2,2'-azinobis(3-ethylbenzothiazoline-6-sulphonic acid))/persulphate, because only these assays were capable of evaluating protein contribution to the observed TAC value. As milk fat caused turbidity, experiments were carried out with skim milk or defatted milk samples. To determine TAC, modified CUPRAC method was applied to whole milk, separated and redissolved protein fractions, and the remaining liquid phase after necessary operations. Both TAC methods were investigated for their dilution sensitivity and antioxidant power assessment of separate milk fractions such as casein and whey. Proteins like β-lactoglobulin and casein (but not simple thiols) exhibited enhanced CUPRAC reactivity with surfactant (SDS) addition. Addition of milk protein fractions to whole skim milk produced significant 'negative-biased' deviations (up to -26% relative standard error) from TAC absorbance additivity in the application of the ABTS method, as opposed to that of the CUPRAC method less affected by chemical deviations from Beer's law thereby producing much smaller deviations from additivity (i.e. the property of additivity is valid when the measured TAC of a mixture is equal to the sum of individual antioxidant capacities of its constituents).

Clarification of dissolved irradiated light-water-reactor fuel

International Nuclear Information System (INIS)

Rodrigues, G.C.

1983-02-01

Bench-scale studies with actual dissolved irradiated light water reactor (LWR) fuels showed that continuous centrifugation is a practical clarification method for reprocessing. Dissolved irradiated LWR fuel was satisfactorily clarified in a bench-scale, continuous-flow bowl centrifuge. The solids separated were successfully reslurried in water. When the reslurried solids were mixed with clarified centrate, the resulting suspension behaved similar to the original dissolver solution during centrifugation. Settling rates for solids in actual irradiated fuel solutions were measured in a bottle centrifuge. The results indicate that dissolver solutions may be clarified under conditions achievable by available plant-scale centrifuge technology. The effective particle diameter of residual solids was calculated to be 0.064 microns for Oconee-1 fuel and 0.138 microns for Dresden-1 fuel. Filtration was shown unsuitable for clarification of LWR fuel solutions. Conventional filtration with filter aid would unacceptably complicate remote canyon operation and maintenance, might introduce dissolved silica from filter aids, and might irreversibly plug the filter with dissolver solids. Inertial filtration exhibited irreversible pluggage with nonradioactive stand-in suspensions under all conditions tested

Contrasted response of colloidal, organic and inorganic dissolved phosphorus forms during rewetting of dried riparian soils

Science.gov (United States)

Gu, Sen; Gruau, Gérard; Malique, François; Dupas, Rémi; Gascuel-Odoux, Chantal; Petitjean, Patrice; Bouhnik-Le Coz, Martine

2017-04-01

Riparian vegetated buffer strip (RVBS) are currently used to protect surface waters from phosphorus (P) emissions because of their ability to retain P-enriched soil particles. However, this protection role may be counterbalanced by the development in these zones of conditions able to trigger the release of highly mobile dissolved or colloidal P forms. Rewetting after drying is one of these conditions. So far, the potential sources of P mobilized during rewetting after drying are not clearly identified, nor are clearly identified the chemical nature of the released dissolved P species, or the role of the soil P speciation on these forms. In this study, two riparian soils (G and K) showing contrasting soil P speciation (65% of inorganic P species in soil G, as against 70% of organic P) were submitted to three successive dry/wet cycles in the laboratory. Conventional colorimetric determination of P concentrations combined with ultrafiltration, and measurements of iron (Fe) and aluminum (Al) and dissolved organic carbon (DOC) contents using ICP-MS and TOC analyzers, respectively, were used to study the response of the different P forms to rewetting after drying and also their release kinetics during soil leaching. For both soils, marked P release peaks were observed at the beginning of each wet cycles, with the organic-rich K soils giving, however, larger peaks than the inorganic one (G soil). For both soils also, concentrations in molybdate reactive P (MRP) remained quite constant throughout each leaching episode, contrary to the molybdate unreactive P (MUP) concentrations which were high immediately after rewetting and then decreased rapidly during leaching. A speciation change was observed from the beginning to the end of all leaching cycles. Colloidal P was found to be a major fraction of the total P immediately after rewetting (up to 50-70%) and then decreased to the end of each wet cycle where most of the eluted P was true dissolved inorganic P. Colloidal

Dilution limits dissolved organic carbon utilization in the deep ocean

KAUST Repository

Arrieta, Jesus

2015-03-19

Oceanic dissolved organic carbon (DOC) is the second largest reservoir of organic carbon in the biosphere. About 72% of the global DOC inventory is stored in deep oceanic layers for years to centuries, supporting the current view that it consists of materials resistant to microbial degradation. An alternative hypothesis is that deep-water DOC consists of many different, intrinsically labile compounds at concentrations too low to compensate for the metabolic costs associated to their utilization. Here, we present experimental evidence showing that low concentrations rather than recalcitrance preclude consumption of a substantial fraction of DOC, leading to slow microbial growth in the deep ocean. These findings demonstrate an alternative mechanism for the long-term storage of labile DOC in the deep ocean, which has been hitherto largely ignored. © 2015, American Association for the Advancement of Science. All rights reserved.

Dilution limits dissolved organic carbon utilization in the deep ocean

KAUST Repository

Arrieta, J M; Mayol, Eva; Hansman, Roberta L.; Herndl, Gerhard J.; Dittmar, Thorsten; Duarte, Carlos M.

2015-01-01

Oceanic dissolved organic carbon (DOC) is the second largest reservoir of organic carbon in the biosphere. About 72% of the global DOC inventory is stored in deep oceanic layers for years to centuries, supporting the current view that it consists of materials resistant to microbial degradation. An alternative hypothesis is that deep-water DOC consists of many different, intrinsically labile compounds at concentrations too low to compensate for the metabolic costs associated to their utilization. Here, we present experimental evidence showing that low concentrations rather than recalcitrance preclude consumption of a substantial fraction of DOC, leading to slow microbial growth in the deep ocean. These findings demonstrate an alternative mechanism for the long-term storage of labile DOC in the deep ocean, which has been hitherto largely ignored. © 2015, American Association for the Advancement of Science. All rights reserved.

Underestimation of phosphorus fraction change in the supernatant after phosphorus adsorption onto iron oxides and iron oxide-natural organic matter complexes.

Science.gov (United States)

Yan, Jinlong; Jiang, Tao; Yao, Ying; Wang, Jun; Cai, Yuanli; Green, Nelson W; Wei, Shiqiang

2017-05-01

The phosphorus (P) fraction distribution and formation mechanism in the supernatant after P adsorption onto iron oxides and iron oxide-humic acid (HA) complexes were analyzed using the ultrafiltration method in this study. With an initial P concentration of 20mg/L (I=0.01mol/L and pH=7), it was shown that the colloid (1kDa-0.45μm) component of P accounted for 10.6%, 11.6%, 6.5%, and 4.0% of remaining total P concentration in the supernatant after P adsorption onto ferrihydrite (FH), goethite (GE), ferrihydrite-humic acid complex (FH-HA), goethite-humic acid complex (GE-HA), respectively. The oxide aggregates was the main mechanism for the formation of the colloid P in the supernatant. And colloidal adsorbent particles co-existing in the supernatant were another important reason for it. Additionally, dissolve organic matter dissolved from iron oxide-HA complexes could occupy large adsorption sites of colloidal iron causing less colloid P in the supernatant. Ultimately, we believe that the findings can provide a new way to deeply interpret the geochemical cycling of P, even when considering other contaminants such as organic pollutants, heavy metal ions, and arsenate at the sediment/soil-water interface in the real environment. Copyright © 2016. Published by Elsevier B.V.

Relation between the amount of dissolved water and metals dissolved from stainless steel or aluminum plate in safflower oil

Energy Technology Data Exchange (ETDEWEB)

Takasago, Masahisa; Takaoka, Kyo

1986-12-01

The amount of water dissolved in safflower oil at the frying temperature (180 deg C) was 518 -- 1012 ppM, allowing water to drop continuously (0.035 g/2 min) into the oil for 1 -- 3 h. When the oil was heated with metal plates under the same conditions, the amount of dissolved water in the oil increased more than in the absence of the metal plates. In case of stainless steel, the amount was 1.26 to 1.33 times, and with aluminum plates, 1.06 to 1.13 times the amount without plates. When these metal plates were heated with the oil under the above conditions, the water dissolved the metal of the plates into the oil. In case of stainless steel, iron dissolved from 0.17 to 0.77 ppM, nickel, 0.04 ppM and chromium, from 0.02 to 0.03 ppM. Similarly, the amount of aluminum dissolved from the aluminum plate was from 0.10 to 0.45 ppM.

Oxidation by UV and ozone of organic contaminants dissolved in deionized and raw mains water

International Nuclear Information System (INIS)

Francis, P.D.

1987-01-01

Organic contaminants dissolved in deionized pretreated and raw mains water were reacted with ultraviolet light and ozone. Ozone first was used for partial oxidation followed by ozone combined with ultraviolet radiation to produce total oxidation. The reduction of total organic carbon (TOC) level and direct oxidation of halogenated compounds were measured throughout the treatment process. The rate of TOC reduction was compared for ozone injected upstream and inside the reactor

ICPP custom dissolver explosion recovery

International Nuclear Information System (INIS)

Demmer, R.; Hawk, R.

1992-01-01

This paper discusses the recovery from the February 9, 1991, small scale explosion in a custom processing dissolver at the Idaho Chemical Processing Plant (ICPP) a Department of Energy facility at the Idaho National Engineering Laboratory. The custom processing facility is a limited production area designed to recover unirradiated uranium fuel. A small amount of the nuclear material received and stored at the ICPP is unique and incompatible with the major head end dissolution processes. Custom processing is a small scale dissolution facility for processing these materials in an economical fashion in the CPP-627 hot chemistry laboratory. Two glass dissolvers were contained in a large walk in hood area. Utilities for dissolution and connections to the major ICPP uranium separation facility were provided. The fuel processing operations during this campaign involved dissolving uranium metal, uranium oxides, and uranium/fissium alloy in nitric acid

Mangroves, a major source of dissolved organic carbon to the oceans

Science.gov (United States)

Dittmar, Thorsten; Hertkorn, Norbert; Kattner, Gerhard; Lara, RubéN. J.

2006-03-01

Organic matter, which is dissolved in low concentrations in the vast waters of the oceans, contains a total amount of carbon similar to atmospheric carbon dioxide. To understand global biogeochemical cycles, it is crucial to quantify the sources of marine dissolved organic carbon (DOC). We investigated the impact of mangroves, the dominant intertidal vegetation of the tropics, on marine DOC inventories. Stable carbon isotopes and proton nuclear magnetic resonance spectroscopy showed that mangroves are the main source of terrigenous DOC in the open ocean off northern Brazil. Sunlight efficiently destroyed aromatic molecules during transport offshore, removing about one third of mangrove-derived DOC. The remainder was refractory and may thus be distributed over the oceans. On a global scale, we estimate that mangroves account for >10% of the terrestrially derived, refractory DOC transported to the ocean, while they cover only <0.1% of the continents' surface.

Dissolving Microneedle Patches for Dermal Vaccination.

Science.gov (United States)

Leone, M; Mönkäre, J; Bouwstra, J A; Kersten, G

2017-11-01

The dermal route is an attractive route for vaccine delivery due to the easy skin accessibility and a dense network of immune cells in the skin. The development of microneedles is crucial to take advantage of the skin immunization and simultaneously to overcome problems related to vaccination by conventional needles (e.g. pain, needle-stick injuries or needle re-use). This review focuses on dissolving microneedles that after penetration into the skin dissolve releasing the encapsulated antigen. The microneedle patch fabrication techniques and their challenges are discussed as well as the microneedle characterization methods and antigen stability aspects. The immunogenicity of antigens formulated in dissolving microneedles are addressed. Finally, the early clinical development is discussed.

The relation between the amount of dissolved water and metals dissolved from stainless steel or aluminum plate in safflower oil

International Nuclear Information System (INIS)

Takasago, Masahisa; Takaoka, Kyo

1986-01-01

The amount of water dissolved in safflower oil at the frying temperature (180 deg C) was 518 ∼ 1012 ppm, allowing water to drop continuously (0.035 g/2 min) into the oil for 1 ∼ 3 h. When the oil was heated with metal plates under the same conditions, the amount of dissolved water in the oil increased more than in the absence of the metal plates. In case of stainless steel, the amount was 1.26 to 1.33 times, and with aluminum plates, 1.06 to 1.13 times the amount without plates. When these metal plates were heated with the oil under the above conditions, the water dissolved the metal of the plates into the oil. In case of stainless steel, iron dissolved from 0.17 to 0.77 ppm, nickel, 0.04 ppm and chromium, from 0.02 to 0.03 ppm. Similarly, the amount of aluminum dissolved from the aluminum plate was from 0.10 to 0.45 ppm. (author)

The Fractionation and Enrichment of La Content by Precipitation

International Nuclear Information System (INIS)

Suyanti; Purwani, MV

2007-01-01

The fractionation and enrichment of La content by precipitation have been done. The feed was La hydroxide by product of monazite sand. La hydroxide was diluted in HNO 3 and was precipitated with ammonia. For to obtain La, diluent was precipitated at pH 8 and the filtrate was precipitated with oxalic acid. The precipitant of La concentrated was more rich than the feed. This process was done continue and fractionally. The best yield of enrichment of La was obtained at dilution of 25 gram La Hydroxide in 20 ml HNO 3 . The efficient degree of fractionation was XV. The average weight of La concentrate was obtained at every fraction was 1 gram. The total sum weight from fraction I until fraction XV 13.5 grams. The average of La content was 48%, average fractionation efficiency of La for every step of fractionation was 48 %. Total efficiency all process was 100%. The average ratio of La/Nd was 2 and the ratio of La/Ce almost infinite. Before processed La/Ce was 7.86, and after process increase to 26.92 - to approach ∞. Before processed ratio of La/Nd was 2.79, after processed increased to 4.4 - to approach ∞. (author)

Dissolved Concentration Limits of Radioactive Elements

Energy Technology Data Exchange (ETDEWEB)

Y. Chen; E.R. Thomas; F.J. Pearson; P.L. Cloke; T.L. Steinborn; P.V. Brady

2003-06-20

The purpose of this study is to evaluate dissolved concentration limits (also referred to as solubility limits) of radioactive elements under possible repository conditions, based on geochemical modeling calculations using geochemical modeling tools, thermodynamic databases, and measurements made in laboratory experiments and field work. The scope of this modeling activity is to predict dissolved concentrations or solubility limits for 14 radioactive elements (actinium, americium, carbon, cesium, iodine, lead, neptunium, plutonium, protactinium, radium, strontium, technetium, thorium, and uranium), which are important to calculated dose. Model outputs are mainly in the form of look-up tables plus one or more uncertainty terms. The rest are either in the form of distributions or single values. The results of this analysis are fundamental inputs for total system performance assessment to constrain the release of these elements from waste packages and the engineered barrier system. Solubilities of plutonium, neptunium, uranium, americium, actinium, thorium, protactinium, lead, and radium have been re-evaluated using the newly updated thermodynamic database (Data0.ymp.R2). For all of the actinides, identical modeling approaches and consistent environmental conditions were used to develop solubility models in this revision. These models cover broad ranges of environmental conditions so that they are applicable to both waste packages and the invert. Uncertainties from thermodynamic data, water chemistry, temperature variation, activity coefficients, and selection of solubility controlling phase have been quantified or otherwise addressed. Moreover, a new blended plutonium solubility model has been developed in this revision, which gives a mean solubility that is three orders of magnitude lower than the plutonium solubility model used for the Total System Performance Assessment for the Site Recommendation. Two alternative neptunium solubility models have also been

Dissolved Concentration Limits of Radioactive Elements

International Nuclear Information System (INIS)

Y. Chen; E.R. Thomas; F.J. Pearson; P.L. Cloke; T.L. Steinborn; P.V. Brady

2003-01-01

The purpose of this study is to evaluate dissolved concentration limits (also referred to as solubility limits) of radioactive elements under possible repository conditions, based on geochemical modeling calculations using geochemical modeling tools, thermodynamic databases, and measurements made in laboratory experiments and field work. The scope of this modeling activity is to predict dissolved concentrations or solubility limits for 14 radioactive elements (actinium, americium, carbon, cesium, iodine, lead, neptunium, plutonium, protactinium, radium, strontium, technetium, thorium, and uranium), which are important to calculated dose. Model outputs are mainly in the form of look-up tables plus one or more uncertainty terms. The rest are either in the form of distributions or single values. The results of this analysis are fundamental inputs for total system performance assessment to constrain the release of these elements from waste packages and the engineered barrier system. Solubilities of plutonium, neptunium, uranium, americium, actinium, thorium, protactinium, lead, and radium have been re-evaluated using the newly updated thermodynamic database (Data0.ymp.R2). For all of the actinides, identical modeling approaches and consistent environmental conditions were used to develop solubility models in this revision. These models cover broad ranges of environmental conditions so that they are applicable to both waste packages and the invert. Uncertainties from thermodynamic data, water chemistry, temperature variation, activity coefficients, and selection of solubility controlling phase have been quantified or otherwise addressed. Moreover, a new blended plutonium solubility model has been developed in this revision, which gives a mean solubility that is three orders of magnitude lower than the plutonium solubility model used for the Total System Performance Assessment for the Site Recommendation. Two alternative neptunium solubility models have also been

Changes in different organic matter fractions during conventional treatment and advanced treatment

Institute of Scientific and Technical Information of China (English)

Chao Chen; Xiaojian Zhang; Lingxia Zhu; Wenjie He; Hongda Han

2011-01-01

XAD-8 resin isolation of organic matter in water was used to divide organic matter into the hydrophobic and hydrophilic fractions.A pilot plant was used to investigate the change in both fractions during conventional and advanced treatment processes.The treatment of hydrophobic organics (HPO), rather than hydrophilic organicas (HPI), should carry greater emphasis due to HPO's higher trihalomethane formation potential (THMFP) and haloacetic acid formation potential (HAAFP).The removal of hydrophobic matter and its transmission into hydrophilic matter reduced ultimate DBP yield during the disinfection process.The results showed that sand filtration, ozonation, and biological activated carbon (BAC) filtration had distinct influences on the removal of both organic fractions.Additionally, the combination of processes changed the organic fraction proportions present during treatment.The use of ozonation and BAC maximized organic matter removal efficiency, especially for the hydrophobic fraction.In sum, the combination of pre-ozonation,conventional treatment, and O3-BAC removed 48％ of dissolved organic carbon (DOC), 60％ of HPO, 30％ of HPI, 63％ of THMFP,and 85％ of HAAFP.The use of conventional treatment and O3-BAC without pre-ozonation had a comparable performance, removing 51％ of DOC, 56％ of HPO, 45％ of HPI, 61％ of THMFP, and 72％ of HAAFP.The effectiveness of this analysis method indicated that resin isolation and fractionation should be standardized as an applicable test to help assess water treatment process efficiency.

Annual and seasonal variation of turbidity, total dissolved solids, nitrate and nitrite in the Parsabad water treatment plant, Iran

Directory of Open Access Journals (Sweden)

Mohammad Reza Zare

2013-01-01

Full Text Available Aims: This study investigated the annual and seasonal variation of turbidity; total dissolved solid (TDS, nitrate and nitrite in Parsabad water treatment plant (WTP, Iran. Materials and Methods: The water samples were obtained from the inlet and outlet of Parsabad WTP from February 2002 to June 2009. The samples′ turbidity, TDS, nitrate, nitrite, pH, and temperature were measured according to standard methods once a month and the average of these parameters were calculated for each season of year. Results: The maximum concentration of inlet turbidity, TDS, nitrate and nitrite were 691, 700.5, 25, and 0.17 mg/l, respectively. These parameters for outlet samples in the study period were 3.0, 696.7, 18, and 0.06 mg/l, respectively. While these concentrations in outlet zone were lower than World Health Organization (WHO or United States Environmental Protection Agency (US-EPA water quality guidelines, WTP could not reduce the TDS, nitrate, nitrite and pH value and these parameters were not different in the inlet and outlet samples. However, the WTP reduced the turbidity significantly with an efficiency of up to 85%. Conclusion: This study showed that a common WTP with rapid sand filtration can treat a maximum river turbidity of 700 NTU in several years. As no differences were observed between inlet and outlet TDS, nitrate, nitrite and pH in the studied WTP. It can be concluded that compensatory schemes should be predicted for modification of these parameters when they exceed the standards in the emergency situations.

Spatial and temporal variations of loads and sources of total and dissolved Phosphorus in a set of rivers (Western France).

Science.gov (United States)

Legeay, Pierre-Louis; Moatar, Florentina; Gascuel-Odoux, Chantal; Gruau, Gérard

2015-04-01

In intensive agricultural regions with important livestock farming, long-term land application of Phosphorus (P) both as chemical fertilizer and animal wastes, have resulted in elevated P contents in soils. Since we know that high P concentrations in rivers is of major concern, few studies have been done at to assess the spatiotemporal variability of P loads in rivers and apportionment of point and nonpoint source in total loads. Here we focus on Brittany (Western France) where even though P is a great issue in terms of human and drinking water safety (cyano-toxins), environmental protection and economic costs for Brittany with regards to the periodic proliferations of cyanobacteria that occur every year in this region, no regional-scale systematic study has been carried out so far. We selected a set of small rivers (stream order 3-5) with homogeneous agriculture and granitic catchment. By gathering data from three water quality monitoring networks, covering more than 100 measurements stations, we provide a regional-scale quantification of the spatiotemporal variability of dissolved P (DP) and total P (TP) interannual loads from 1992 to 2012. Build on mean P load in low flows and statistical significance tests, we developed a new indicator, called 'low flow P load' (LFP-load), which allows us to determine the importance of domestic and industrial P sources in total P load and to assess their spatiotemporal variability compared to agricultural sources. The calculation and the map representation of DP and TP interannual load variations allow identification of the greatest and lowest P contributory catchments over the study period and the way P loads of Brittany rivers have evolved through time. Both mean DP and TP loads have been divided by more than two over the last 20 years. Mean LFDP-load decreased by more than 60% and mean LFTP-load by more than 45% on average over the same period showing that this marked temporal decrease in total load is largely due to the

Effects of dissolved organic matter from a eutrophic lake on the freely dissolved concentrations of emerging organic contaminants.

Science.gov (United States)

Xiao, Yi-Hua; Huang, Qing-Hui; Vähätalo, Anssi V; Li, Fei-Peng; Chen, Ling

2014-08-01

The authors studied the effects of dissolved organic matter (DOM) on the bioavailability of bisphenol A (BPA) and chloramphenicol by measuring the freely dissolved concentrations of the contaminants in solutions containing DOM that had been isolated from a mesocosm in a eutrophic lake. The abundance and aromaticity of the chromophoric DOM increased over the 25-d mesocosm experiment. The BPA freely dissolved concentration was 72.3% lower and the chloramphenicol freely dissolved concentration was 56.2% lower using DOM collected on day 25 than using DOM collected on day 1 of the mesocosm experiment. The freely dissolved concentrations negatively correlated with the ultraviolent absorption coefficient at 254 nm and positively correlated with the spectral slope of chromophoric DOM, suggesting that the bioavailability of these emerging organic contaminants depends on the characteristics of the DOM present. The DOM-water partition coefficients (log KOC ) for the emerging organic contaminants positively correlated with the aromaticity of the DOM, measured as humic acid-like fluorescent components C1 (excitation/emission=250[313]/412 nm) and C2 (excitation/emission=268[379]/456 nm). The authors conclude that the bioavailability of emerging organic contaminants in eutrophic lakes can be affected by changes in the DOM. © 2014 SETAC.

Hg isotopes reveal in-stream processing and legacy inputs in East Fork Poplar Creek, Oak Ridge, Tennessee, USA.

Science.gov (United States)

Demers, Jason D; Blum, Joel D; Brooks, Scott C; Donovan, Patrick M; Riscassi, Ami L; Miller, Carrie L; Zheng, Wang; Gu, Baohua

2018-04-25

Natural abundance stable Hg isotope measurements were used to place new constraints on sources, transport, and transformations of Hg along the flow path of East Fork Poplar Creek (EFPC), a point-source contaminated headwater stream in Oak Ridge, Tennessee. Particulate-bound Hg in the water column of EFPC within the Y-12 National Security Complex, was isotopically similar to average metallic Hg(0) used in industry, having a mean δ202Hg value of -0.42 ± 0.09‰ (1SD) and near-zero Δ199Hg. On average, particulate fraction δ202Hg values increased downstream by 0.53‰, while Δ199Hg decreased by -0.10‰, converging with the Hg isotopic composition of the fine fraction of streambed sediment along the 26 km flow path. The dissolved fraction behaved differently. Although initial Δ199Hg values of the dissolved fraction were also near-zero, these values increased transiently along the flow path. Initial δ202Hg values of the dissolved fraction were more variable than in the particulate fraction, ranging from -0.44 to 0.18‰ among three seasonal sampling campaigns, but converged to an average δ202Hg value of 0.01 ± 0.10‰ (1SD) downstream. Dissolved Hg in the hyporheic and riparian pore water had higher and lower δ202Hg values, respectively, compared to dissolved Hg in stream water. Variations in Hg isotopic composition of the dissolved and suspended fractions along the flow path suggest that: (1) physical processes such as dilution and sedimentation do not fully explain decreases in total mercury concentrations along the flow path; (2) in-stream processes include photochemical reduction, but microbial reduction is likely more dominant; and (3) additional sources of dissolved mercury inputs to EFPC at baseflow during this study predominantly arise from the hyporheic zone.

Dissolved Organic Matter Composition and Export from U.S. Rivers

Science.gov (United States)

Aiken, G.; Butman, D. E.; Spencer, R. G.; Raymond, P.

2012-12-01

Dissolved organic matter (DOM) chemistry and flux are potentially useful indicators of watershed characteristics, climate influences on watershed hydrology and soils, and changes associated with water and land resource management. Organic source materials, watershed geochemistry, oxidative processes and hydrology strongly influence the nature and reactivity of DOM in aquatic systems. The molecules that comprise DOM, in turn, control a number of environmental processes important for ecosystem function including light penetration and photochemistry, microbial activity, mineral dissolution/precipitation, and the transport and reactivity of hydrophobic compounds and metals. In particular, aromatic molecules derived from higher plants exert strong controls on aquatic photochemistry, and on the transport and biogeochemistry of metals. Assessment of DOM composition and transport, therefore, can provide a basis for understanding watershed processes and biogeochemistry of rivers and streams. Here we present results of a multi-year study designed to assess the seasonal and spatial variability of DOM quantity and quality for 15 large North American river basins. Samples were collected from the mouths of the rivers using a sampling program designed to capture hydrologic and seasonal variability of DOM export. DOM concentrations and composition, based on DOM fractionation on XAD resins, chromophoric dissolved organic matter (CDOM) parameters (ultraviolet /visible absorption and fluorescence spectroscopy), specific compound analyses, and DO14C content varied greatly both between sites and seasonally within a given site. DOM in these rivers exhibited a wide range of concentration and carbon specific ultra-violet absorbance at 254 nm (SUVA254), an optical measurement that is an indicator of DOM aromatic carbon content. In almost all systems, CDOM optical parameters correlated strongly with DOC concentration and hydrophobic organic acid (HPOA) content (aquatic humic substances). In

Chemical composition of material fractions in Danish household waste

DEFF Research Database (Denmark)

Riber, Christian; Petersen, Claus; Christensen, Thomas Højlund

2009-01-01

batches of 80-1200 tonnes of unsorted household waste was incinerated and the content of the waste determined from the content of the outputs from the incinerator. The indirect method is believed to better represent the small but highly contaminated material fractions (e,g., batteries) than the direct...... like paper, cardboard anti organic fractions. The single fraction contributing most to the total energy content is the non-recyclable plastic fraction, contributing 21% of the energy content and 60% of the chlorine content, although this fraction comprises less than 7% by weight. Heavy metals originate...... mainly from inert fractions, primarily batteries....

METHOD OF DISSOLVING URANIUM METAL

Science.gov (United States)

Slotin, L.A.

1958-02-18

This patent relates to an economicai means of dissolving metallic uranium. It has been found that the addition of a small amount of perchloric acid to the concentrated nitric acid in which the uranium is being dissolved greatly shortens the time necessary for dissolution of the metal. Thus the use of about 1 or 2 percent of perchioric acid based on the weight of the nitric acid used, reduces the time of dissolution of uranium by a factor of about 100.

Ice Harbor Spillway Dissolved Gas Field Studies: Before and After Spillway Deflectors

Science.gov (United States)

2016-07-01

Steven C. Wilhelms Coastal And Hydraulics Laboratory U.S. Army Engineer Research and Development Center 3909 Halls Ferry Road Vicksburg, Mississippi...Harbor as a measure to reduce the total dissolved gas (TDG) production during spill operations. Three field studies were conducted at the Ice Harbor...significantly reduced for nearly all spill operations with deflectors in place. TDG near the stilling basin was reduced from approximately 150% to

Photomineralization and photomethanification of dissolved organic matter in Saguenay River surface water

Science.gov (United States)

Zhang, Y.; Xie, H.

2015-11-01

Rates and apparent quantum yields of photomineralization (AQYDOC) and photomethanification (AQYCH4) of chromophoric dissolved organic matter (CDOM) in Saguenay River surface water were determined at three widely differing dissolved oxygen concentrations ([O2]) (suboxic, air saturation, and oxygenated) using simulated-solar radiation. Photomineralization increased linearly with CDOM absorbance photobleaching for all three O2 treatments. Whereas the rate of photochemical dissolved organic carbon (DOC) loss increased with increasing [O2], the ratio of fractional DOC loss to fractional absorbance loss showed an inverse trend. CDOM photodegradation led to a higher degree of mineralization under suboxic conditions than under oxic conditions. AQYDOC determined under oxygenated, suboxic, and air-saturated conditions increased, decreased, and remained largely constant with photobleaching, respectively; AQYDOC obtained under air saturation with short-term irradiations could thus be applied to longer exposures. AQYDOC decreased successively from ultraviolet B (UVB) to ultraviolet A (UVA) to visible (VIS), which, alongside the solar irradiance spectrum, points to VIS and UVA being the primary drivers for photomineralization in the water column. The photomineralization rate in the Saguenay River was estimated to be 2.31 × 108 mol C yr-1, accounting for only 1 % of the annual DOC input into this system. Photoproduction of CH4 occurred under both suboxic and oxic conditions and increased with decreasing [O2], with the rate under suboxic conditions ~ 7-8 times that under oxic conditions. Photoproduction of CH4 under oxic conditions increased linearly with photomineralization and photobleaching. Under air saturation, 0.00057 % of the photochemical DOC loss was diverted to CH4, giving a photochemical CH4 production rate of 4.36 × 10-6 mol m-2 yr-1 in the Saguenay River and, by extrapolation, of (1.9-8.1) × 108 mol yr-1 in the global ocean. AQYCH4 changed little with

Morphological correlates of fractionated radiation of the mouse lung: Early and late effects

International Nuclear Information System (INIS)

Penney, D.P.; Siemann, D.W.; Rubin, P.; Maltby, K.

1994-01-01

The definition and quantitation of radiation-induced morphologic alterations in murine lungs is presented. The extent of injury to the lung, which is the dose-limiting organ in the thorax, may be reduced by fractionating the total radiation exposure to permit partial repair of radiation-induced damage between fraction administration and also to permit a larger total exposure to be administered. The authors previously reported that, following fractionated radiation exposures, as the dose/fraction decreases, the total dose to reach an isoeffect increases, with an α/β ratio of 3.2 and 3.0 for breathing rates and lethality, respectively. In the present report, they provide comparative morphologic evaluation of the effects of weekly fractionated, daily fractionated, and hyperfractionated radiation exposures. The doses administered within each group were uniform. To determine morphologic alterations, LAF1 mice were irradiated with 3, 15, and 30 fractions delivered in 19 days overall treatment time. In the hyperfractionation schedule, the two fractions per day were separated by a 6-h time interval. Total doses were as follows: 15-21 Gy for weekly fractionation, 30-41.5 Gy for daily fractionation, and 30-49.5 Gy for hyperfractionated schedules. Lung tissue, recovered either 24 or 72 weeks following the final exposure, was evaluated by transmission and scanning electron microscopy and light microscopy. Morphological damage was not uniform throughout the exposed lung and tended to be concentrated in lobes or portions of lobes. In the three fractionation regimens studied, there is progressive sparing of the lung with increased fractionation during the pnuemonitic state (24 weeks postirradiation). Both daily and twice daily fractionations provide increased sparing over weekly fractionation during the fibrotic stages (72 weeks postirradiation), but were not markedly different from each other (i.e. weekly < daily = twice daily). 41 refs., 15 figs., 2 tabs

Evaluation of water quality by chlorophyll and dissolved oxygen

International Nuclear Information System (INIS)

Latif, Z.; Tasneem, M.A.; Javed, T.; Butt, S.; Fazil, M.; Ali, M.; Sajjad, M.I.

2002-01-01

This paper focuses on the impact of Chlorophyll and dissolved Oxygen on water quality. Kalar Kahar and Rawal lakes were selected for this research. A Spectrophotometer was used for determination of Chlorophyll a, Chlorophyll b, Chlorophyll c and Pheophytin pigment. Dissolved Oxygen was measured in situ, using dissolved oxygen meter. The gamma O/sup 18/ of dissolved Oxygen, like concentration, is affected primarily by three processes: air water gas exchange, respiration and photosynthesis; gamma O/sup 18/ is analyzed on isotopic ratio mass spectrometer, after extraction of dissolved Oxygen from water samples, followed by purification and conversion into CO/sub 2/. Rawal lake receives most of the water from precipitation during monsoon period and supplemented by light rains in December and January. This water is used throughout the year for drinking purposes in Rawalpindi city. The water samples were collected from 5, 7.5, and 10 meters of depth for seasonal studies of physiochemical and isotopic parameters of water and dissolved Oxygen. Optimum experimental conditions for delta O/sup 18/ analysis of dissolved Oxygen from aqueous samples were determined. Stratification of dissolved Oxygen was observed in Rawal Lake before rainy season in summer. The water quality deteriorates with depth, because the respiration exceeds the photosynthesis and gas exchange. The concentration and delta O/sup 18/ of dissolved Oxygen show no variation with depth in 1998 winter sampling. Kalar Kahar lake gets water from springs, which are recharged by local rains on the nearby mountains. It is a big lake, with shallow and uniform depth of nearly 1.5 meters. A lot of vegetation can be seen on the periphery of the lake. Algae have grown on the floor of the lake Water samples were collected from the corner with large amount of vegetation and from the center of the lake for dissolved Oxygen and Chlorophyll measurements. Chlorophyll result shows that Kalar Kahar Lake falls in Eutrophic category

Cellulase activity and dissolved organic carbon release from lignocellulose macrophyte-derived in four trophic conditions.

Science.gov (United States)

Bottino, Flávia; Cunha-Santino, Marcela Bianchessi; Bianchini, Irineu

2016-01-01

Considering the importance of lignocellulose macrophyte-derived for the energy flux in aquatic ecosystems and the nutrient concentrations as a function of force which influences the decomposition process, this study aims to relate the enzymatic activity and lignocellulose hydrolysis in different trophic statuses. Water samples and two macrophyte species were collected from the littoral zone of a subtropical Brazilian Reservoir. A lignocellulosic matrix was obtained using aqueous extraction of dried plant material (≈40°C). Incubations for decomposition of the lignocellulosic matrix were prepared using lignocelluloses, inoculums and filtered water simulating different trophic statuses with the same N:P ratio. The particulate organic carbon and dissolved organic carbon (POC and DOC, respectively) were quantified, the cellulase enzymatic activity was measured by releasing reducing sugars and immobilized carbon was analyzed by filtration. During the cellulose degradation indicated by the cellulase activity, the dissolved organic carbon daily rate and enzyme activity increased. It was related to a fast hydrolysable fraction of cellulose that contributed to short-term carbon immobilization (ca. 10 days). After approximately 20 days, the dissolved organic carbon and enzyme activity were inversely correlated suggesting that the respiration of microorganisms was responsible for carbon mineralization. Cellulose was an important resource in low nutrient conditions (oligotrophic). However, the detritus quality played a major role in the lignocelluloses degradation (i.e., enzyme activity) and carbon release. Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

Hydrographic parameters and distribution of dissolved Cu, Ni, Zn and nutrients near Jeddah desalination plant

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Fallatah Mohammad M.

2018-04-01

Full Text Available The development of safe desalination plants with low environmental impact is as important an issue as the supply of drinking water. The desalination plant in Jeddah (Saudi Arabia, Red Sea coast produces freshwater from seawater by multi-stage flash distillation (MSFD and reverse osmosis (RO. The process produces brine as by-product, which is dumped into the sea. The aim of this study was to assess the impact of Jeddah desalination plant on the coastal water in the nearby of the plant. Total concentrations of dissolved Cu, Ni, Zn and nutrients in several locations around the plant were analyzed by cathodic stripping voltammetry. The average levels of dissolved Cu, Ni, and Zn on surface in the sampling locations were 15.02, 11.02, and 68.03 nM respectively, whereas the levels at the seafloor near the discharging point were much higher. Distribution of temperature, salinity, nutrients and dissolved oxygen were quite normal both on surface and in depth.

Phosphorus fractions, microbial biomass and enzyme activities in ...

African Journals Online (AJOL)

Potohar, northern Punjab, Pakistan in September, 2008 and analysed for P fractions and microbial parameters including microbial biomass C, microbial biomass N, microbial biomass P, and activities of dehydrogenase and alkaline phosphatase enzymes. The average size of different P fractions (% of total P) in the soils ...

Chemical attributes, total organic carbon stock and humified fractions of organic matter soil submitted to different systems of sugarcane management

Directory of Open Access Journals (Sweden)

Jean Sérgio Rosset

2014-10-01

Full Text Available Mechanized harvesting maintenance of trash from cane sugar and soil application of waste as vinasse and filter cake can improve the system of crop yield. Thus, this study aimed to evaluate the changes in the chemical, the stock of total organic carbon and humified organic matter fractions in an Oxisol cultivated with cane sugar with the following management systems: with sugarcane vinasse application (CCV, without application of burnt cane waste (CQS, with burnt cane vinasse application (CQV, with application of burnt cane filter cake (CQTF and burnt cane with joint application of vinasse and filter cake (CQVTF. For reference we used an area of natural vegetation (NV, Cerrado sensu stricto. Treatment CQVTF showed improvement in soil chemical properties, increased inventory levels of total organic carbon – TOC (values ranging from 21.28 to 40.02 Mg ha-1 and humified fractions of soil organic matter in relation to other treatments. The CQS area at a depth of 0-0.05 m, showed the greatest losses of soil TOC stocks (56.3% compared to NV. The adoption of management presented CCV and chemical attributes of the soil TOC stocks equivalent to those observed in areas with CQV CQTF and despite the short period of adoption (3 years. The TOC correlated with the sum of bases (r = 0.76 **, cation exchange capacity (r = 0.59 ** and base saturation (r = 0.63 **, while the humic acids (r = 0.40 ** fulvic acids (r = 0.49 ** and humin (r = 0.59 ** correlated with the cation exchange capacity of the soil. These results indicate that the preservation of trash in the management of cane sugar added to the application of vinasse and filter cake increases the TOC stocks promoting improvement in soil chemical properties.

Copper isotope fractionation between aqueous compounds relevant to low temperature geochemistry and biology

Science.gov (United States)

Fujii, Toshiyuki; Moynier, Frédéric; Abe, Minori; Nemoto, Keisuke; Albarède, Francis

2013-06-01

Isotope fractionation between the common Cu species present in solution (Cu+, Cu2+, hydroxide, chloride, sulfide, carbonate, oxalate, and ascorbate) has been investigated using both ab initio methods and experimental solvent extraction techniques. In order to establish unambiguously the existence of equilibrium isotope fractionation (as opposed to kinetic isotope fractionation), we first performed laboratory-scale liquid-liquid distribution experiments. Upon exchange between HCl medium and a macrocyclic complex, the 65Cu/63Cu ratio fractionated by -1.06‰ to -0.39‰. The acidity dependence of the fractionation was appropriately explained by ligand exchange reactions between hydrated H2O and Cl- via intramolecular vibrations. The magnitude of the Cu isotope fractionation among important Cu ligands was also estimated by ab initio methods. The magnitude of the nuclear field shift effect to the Cu isotope fractionation represents only ˜3% of the mass-dependent fractionation. The theoretical estimation was expanded to chlorides, hydroxides, sulfides, sulfates, and carbonates under different conditions of pH. Copper isotope fractionation of up to 2‰ is expected for different forms of Cu present in seawater and for different sediments (carbonates, hydroxides, and sulfides). We found that Cu in dissolved carbonates and sulfates is isotopically much heavier (+0.6‰) than free Cu. Isotope fractionation of Cu in hydroxide is minimal. The relevance of these new results to the understanding of metabolic processes was also discussed. Copper is an essential element used by a large number of proteins for electron transfer. Further theoretical estimates of δ65Cu in hydrated Cu(I) and Cu(II) ions, Cu(II) ascorbates, and Cu(II) oxalate predict Cu isotope fractionation during the breakdown of ascorbate into oxalate and account for the isotopically heavy Cu found in animal kidneys.

Storage effects on quantity and composition of dissolved organic carbon and nitrogen of lake water, leaf leachate and peat soil water.

Science.gov (United States)

Heinz, Marlen; Zak, Dominik

2018-03-01

This study aimed to evaluate the effects of freezing and cold storage at 4 °C on bulk dissolved organic carbon (DOC) and nitrogen (DON) concentration and SEC fractions determined with size exclusion chromatography (SEC), as well as on spectral properties of dissolved organic matter (DOM) analyzed with fluorescence spectroscopy. In order to account for differences in DOM composition and source we analyzed storage effects for three different sample types, including a lake water sample representing freshwater DOM, a leaf litter leachate of Phragmites australis representing a terrestrial, 'fresh' DOM source and peatland porewater samples. According to our findings one week of cold storage can bias DOC and DON determination. Overall, the determination of DOC and DON concentration with SEC analysis for all three sample types were little susceptible to alterations due to freezing. The findings derived for the sampling locations investigated here may not apply for other sampling locations and/or sample types. However, DOC size fractions and DON concentration of formerly frozen samples should be interpreted with caution when sample concentrations are high. Alteration of some optical properties (HIX and SUVA 254 ) due to freezing were evident, and therefore we recommend immediate analysis of samples for spectral analysis. Copyright © 2017 Elsevier Ltd. All rights reserved.

Characterization of dissolved organic material in the interstitial brine of Lake Vida, Antarctica

Science.gov (United States)

Cawley, Kaelin M.; Murray, Alison E.; Doran, Peter T.; Kenig, Fabien; Stubbins, Aron; Chen, Hongmei; Hatcher, Patrick G.; McKnight, Diane M.

2016-06-01

Lake Vida (LV) is located in the McMurdo Dry Valleys (Victoria Valley, East Antarctica) and has no inflows, outflows, or connectivity to the atmosphere due to a thick (16 m), turbid ice surface and cold (organic carbon concentration (DOC; 580 mg-C L-1 or greater); the study of which provides a unique opportunity to better understand biological and/or abiotic processes taking place in an isolated saline ecosystem with no external inputs. We isolated two sub-fractions of LV dissolved organic matter (DOM) by chemical separation using XAD-8 and XAD-4 resins in series. This separation was followed by physical separation using ultrafiltration to isolate a higher molecular weight (HMW) fraction that was retained by the membrane and a salty, dilute low molecular weight fraction. This analytical path resulted in three, low salt sub-fractions and allowed comparison to other Antarctic lake DOM samples isolated using similar procedures. Compared to other Antarctic lakes, a lower portion of the DOC was retained by XAD-8 (∼10% vs. 16-24%) resin, while the portions retained by XAD-4 (∼8%) resin and the 1 kDa ultrafiltration membrane (∼50%) were similar. The 14C radiocarbon ages of the XAD-8 (mean 3940 ybp), XAD-4 (mean 4048 ybp) and HMW (mean 3270 ybp) fractions are all older than the apparent age of ice-cover formation (2800 ybp). Ultrahigh resolution mass spectrometry showed that compounds with two and three nitrogen atoms in the molecular formulas were common in both the LV-XAD8 and LV-XAD4 fractions, consistent with microbial production and processing. The long-term oxidation of LVBr DOM by abiotic oxidants including perchlorate and chlorate may explain the low portion in the XAD8 fraction and the lack of aromatic carbon, as measured by 13C NMR spectroscopy, found for all but the most hydrophobic fraction, LV-XAD8. Overall, the chemical characteristics of Lake Vida brine DOM suggest that legacy DOM sealed and concentrated within the brine has been altered due to a

Natural abundances of /sup 15/N as a source indicator for near-shore marine sedimentary and dissolved nitrogen

Energy Technology Data Exchange (ETDEWEB)

Sweeney, R E; Kaplan, I R [California Univ., Los Angeles (USA). Inst. of Geophysics and Planetary Physics

1980-04-01

The nitrogen isotope ratios of 42 sediment samples of total nitrogen and 38 dissolved pore-water ammonium samples from Santa Barbara Basin sediment cores were measured. The range of delta/sup 15/N values for total nitrogen was +2.89 to +9.4 per thousand with a mean of +6.8 per thousand and for pore water ammonium, +8.2 to +12.4 per thousand with a mean of 10.2 per thousand. The results suggest that the dissolved ammonium in the pore water is produced from bacterial degradation of marine organic matter. The range of delta /sup 15/N values for total nitrogen in the sediment is interpreted as resulting from an admixture of nitrogen derived from marine (+10 per thousand) and terrestrial (+2 per thousand) cores. The marine component of this mixture, composed principally of calcium carbonate with smaller amounts of opal and organic matter, contains approximately 1.0% nitrogen. The terrestrial component, which comprises over 80% of the sediment, contains approximately 0.1% organically bound nitrogen and accounts for > 25% of the total nitrogen in Santa Barbara Basin sediment.

The release of dissolved nutrients and metals from coastal sediments due to resuspension

Science.gov (United States)

Kalnejais, Linda H.; Martin, William R.; Bothner, Michael H.

2010-01-01

Coastal sediments in many regions are impacted by high levels of contaminants. Due to a combination of shallow water depths, waves, and currents, these sediments are subject to regular episodes of sediment resuspension. However, the influence of such disturbances on sediment chemistry and the release of solutes is poorly understood. The aim of this study is to quantify the release of dissolved metals (iron, manganese, silver, copper, and lead) and nutrients due to resuspension in Boston Harbor, Massachusetts, USA. Using a laboratory-based erosion chamber, a range of typical shear stresses was applied to fine-grained Harbor sediments and the solute concentration at each shear stress was measured. At low shear stress, below the erosion threshold, limited solutes were released. Beyond the erosion threshold, a release of all solutes, except lead, was observed and the concentrations increased with shear stress. The release was greater than could be accounted for by conservative mixing of porewaters into the overlying water, suggesting that sediment resuspension enhances the release of nutrients and metals to the dissolved phase. To address the long-term fate of resuspended particles, samples from the erosion chamber were maintained in suspension for 90. h. Over this time, 5-7% of the particulate copper and silver was released to the dissolved phase, while manganese was removed from solution. Thus resuspension releases solutes both during erosion events and over a longer timescale due to reactions of suspended particles in the water column. The magnitude of the annual solute release during erosion events was estimated by coupling the erosion chamber results with a record of bottom shear stresses simulated by a hydrodynamic model. The release of dissolved copper, lead, and phosphate due to resuspension is between 2% and 10% of the total (dissolved plus particulate phase) known inputs to Boston Harbor. Sediment resuspension is responsible for transferring a significant

Accumulation of free and covalently bound microcystins in tissues of Lymnaea stagnalis (Gastropoda) following toxic cyanobacteria or dissolved microcystin-LR exposure

International Nuclear Information System (INIS)

Lance, Emilie; Neffling, Milla-Riina; Gerard, Claudia; Meriluoto, Jussi; Bormans, Myriam

2010-01-01

Accumulation of free microcystins (MCs) in freshwater gastropods has been demonstrated but accumulation of MCs covalently bound to tissues has never been considered so far. Here, we follow the accumulation of total (free and bound) MCs in Lymnaea stagnalis exposed to i) dissolved MC-LR (33 and 100 μg L -1 ) and ii) Planktothrix agardhii suspensions producing 5 and 33 μg MC-LR equivalents L -1 over a 5-week period, and after a 3-week depuration period. Snails exposed to dissolved MC-LR accumulated up to 0.26 μg total MCs g -1 dry weight (DW), with no detection of bound MCs. Snails exposed to MCs producing P. agardhii accumulated up to 69.9 μg total MCs g -1 DW, of which from 17.7 to 66.7% were bound. After depuration, up to 15.3 μg g -1 DW of bound MCs were detected in snails previously exposed to toxic cyanobacteria, representing a potential source of MCs transfer through the food web. - The study concerns accumulation and elimination of both free and bound microcystins (MCs) in tissues of a gastropod exposed to MCs producing cyanobacteria or dissolved MC-LR.

Accumulation of free and covalently bound microcystins in tissues of Lymnaea stagnalis (Gastropoda) following toxic cyanobacteria or dissolved microcystin-LR exposure

Energy Technology Data Exchange (ETDEWEB)

Lance, Emilie, E-mail: emilie.lance@live.f [UMR CNRS Ecobio 6553, University of Rennes 1, Campus de Beaulieu, 265 Avenue du General Leclerc, 35042 Rennes Cedex (France); Neffling, Milla-Riina [Department of Biochemistry and Pharmacy, Abo Akademi University, Tykistoekatu 6, FI-20520 Turku (Finland); Gerard, Claudia [UMR CNRS Ecobio 6553, University of Rennes 1, Campus de Beaulieu, 265 Avenue du General Leclerc, 35042 Rennes Cedex (France); Meriluoto, Jussi [Department of Biochemistry and Pharmacy, Abo Akademi University, Tykistoekatu 6, FI-20520 Turku (Finland); Bormans, Myriam [UMR CNRS Ecobio 6553, University of Rennes 1, Campus de Beaulieu, 265 Avenue du General Leclerc, 35042 Rennes Cedex (France)

2010-03-15

Accumulation of free microcystins (MCs) in freshwater gastropods has been demonstrated but accumulation of MCs covalently bound to tissues has never been considered so far. Here, we follow the accumulation of total (free and bound) MCs in Lymnaea stagnalis exposed to i) dissolved MC-LR (33 and 100 mug L{sup -1}) and ii) Planktothrix agardhii suspensions producing 5 and 33 mug MC-LR equivalents L{sup -1} over a 5-week period, and after a 3-week depuration period. Snails exposed to dissolved MC-LR accumulated up to 0.26 mug total MCs g{sup -1} dry weight (DW), with no detection of bound MCs. Snails exposed to MCs producing P. agardhii accumulated up to 69.9 mug total MCs g{sup -1} DW, of which from 17.7 to 66.7% were bound. After depuration, up to 15.3 mug g{sup -1} DW of bound MCs were detected in snails previously exposed to toxic cyanobacteria, representing a potential source of MCs transfer through the food web. - The study concerns accumulation and elimination of both free and bound microcystins (MCs) in tissues of a gastropod exposed to MCs producing cyanobacteria or dissolved MC-LR.

Influence of the soluble fraction of blast furnace slag on the growth of some algae

Energy Technology Data Exchange (ETDEWEB)

Tokuda, H.

1977-01-01

The sea water-soluble fraction of the pulverized slag was prepared in anaerobic condition, and mixed with a basal medium in various ratios for preparation of a culture medium, on which the growth of a diatom, Skeletonema costatum, was suppressed. The inhibitory effect of the soluble fraction to this alga was reduced to a certain degree when the culture medium had been aerated with nitrogen preceding inoculation. The growth of Skel. costatum was also inhibited on the basal medium containing the untreated slag powder in various amounts, while it was stimulated when the slag powder was washed for several days before addition to the basal medium. The soluble fraction of the slag affected unfavorably the growth of a laver, Porphyra yezoensis, also. A diatom, Nitzschia closterium, was able to grow closely adhering to the slag powder. The inhibitory effect of the soluble fraction of the slag to algae seems to be caused largely by potassium or sodium sulfide, and slightly by sulfur oxides and some heavy metals dissolved in trace amounts.

Factors influencing the dissolved iron input by river water to the open ocean

Directory of Open Access Journals (Sweden)

R. Krachler

2005-01-01

Full Text Available The influence of natural metal chelators on the bio-available iron input to the ocean by river water was studied. Ferrous and ferric ions present as suspended colloidal particles maintaining the semblance of a dissolved load are coagulated and settled as their freshwater carrier is mixed with seawater at the continental boundary. However, we might argue that different iron-binding colloids become sequentially destabilized in meeting progressively increasing salinities. By use of a 59Fe tracer method, the partitioning of the iron load from the suspended and dissolved mobile fraction to storage in the sediments was measured with high accuracy in mixtures of natural river water with artificial sea water. The results show a characteristic sequence of sedimentation. Various colloids of different stability are removed from a water of increasing salinity, such as it is the case in the transition from a river water to the open sea. However, the iron transport capacities of the investigated river waters differed greatly. A mountainous river in the Austrian Alps would add only about 5% of its dissolved Fe load, that is about 2.0 µg L-1 Fe, to coastal waters. A small tributary draining a sphagnum peat-bog, which acts as a source of refractory low-molecular-weight fulvic acids to the river water, would add approximately 20% of its original Fe load, that is up to 480 µg L-1 Fe to the ocean's bio-available iron pool. This points to a natural mechanism of ocean iron fertilization by terrigenous fulvic-iron complexes originating from weathering processes occurring in the soils upstream.

Diatom-induced silicon isotopic fractionation in Antarctic sea ice

Science.gov (United States)

Francois, F.; Damien, C.; Jean-Louis, T.; Anthony, W.; Luc, A.

2006-12-01

We measured silicon-isotopic composition of dissolved silicon and biogenic silica collected by sequential melting from spring 2003 Antarctic pack ice (Australian sector). Sea ice is a key ecosystem in the Southern Ocean and its melting in spring has been often thought to have a seeding effect for the surface waters, triggering blooms in the mixed layer. This work is the first investigation of the silicon isotopes' proxy in sea ice and allows to estimate the activity of sea-ice diatoms in the different brine structures and the influence of sea- ice diatoms on the spring ice edge blooms. The relative use of the dissolved silicon pool by sea-ice diatoms is usually assessed by calculating nutrient:salinity ratios in the brines. However such an approach is biased by difficulties in evaluating the initial nutrient concentrations in the different brines structures, and by the impossibility to account for late sporadic nutrient replenishments. The silicon-isotopic composition of biogenic silica is a convenient alternative since it integrates an average Si utilization on all generations of diatoms. Measurements were performed on a MC-ICP-MS, in dry plasma mode using external Mg doping. Results are expressed as delta29Si relative to the NBS28 standard. From three sea ice cores with contrasted physico-chemical characteristics, we report significant isotopic fractionations linked to the diatoms activity, with distinct silicon biogeochemical dynamics between different brine structure. The diatoms in snow ice and in brine pockets of frazil or congelation ice have the most positive silicon-isotopic composition (+0.53 to +0.86 p.mil), indicating that they grow in a closed system and use a significant part of the small dissolved silicon pool. In the brine channels and skeletal layer, diatoms display a relatively less positive Si-isotopic composition (+0.41 to +0.70 p.mil), although it is still heavier compared to equilibrium fractionation (+0.38 p.mil). This suggests that they have

Mercury isotope fractionation during transfer from post-desulfurized seawater to air.

Science.gov (United States)

Huang, Shuyuan; Lin, Kunning; Yuan, Dongxing; Gao, Yaqin; Sun, Lumin

2016-12-15

Samples of dissolved gaseous mercury (DGM) in the post-desulfurized seawater discharged from a coal-fired power plant together with samples of gaseous elemental mercury (GEM) over the post-desulfurized seawater surface were collected and analyzed to study the mercury isotope fractionation during transfer from post-desulfurized seawater to air. Experimental results showed that when DGM in the seawater was converted to GEM in the air, the δ 202 Hg and Δ 199 Hg values were changed, ranging from -2.98 to -0.04‰ and from -0.31 to 0.64‰, respectively. Aeration played a key role in accelerating the transformation of DGM to GEM, and resulted in light mercury isotopes being more likely to be enriched in the GEM. The ratio Δ 199 Hg/Δ 201 Hg was 1.626 in all samples, suggesting that mercury mass independent fractionation occurred owing to the nuclear volume effect during the transformation. In addition, mass independent fractionation of mercury even isotopes was found in the GEM above the post-desulfurized seawater surface in the aeration pool. Copyright © 2016 Elsevier Ltd. All rights reserved.

In-situ, high pressure and temperature experimental determination of hydrogen isotope fractionation between coexisting hydrous melt and silicate-saturated aqueous fluid

Science.gov (United States)

Mysen, B. O.

2012-12-01

- and pressure range of the experiments discussed here, water in melts is much less important than silicate in aqueous fluid because even at the lowest temperature and pressure conditions studied (450C/101 MPa), the water content in the melt is so high (> 4 wt%) that further increase in total water by increasing temperature and pressure predominantly increases the concentration of molecular H2O in the melts. Water dissolved in molecular form does not affect the silicate melt structure significantly. Therefore, in the deep crust and upper mantle, isotope fractionation factors between fluid and condensed silicate materials (melts and minerals) can differ substantially from isotope fractionation between pure H2O condensed silicate materials. [1] Foustoukos, D. I., and Mysen, B. O. (2012), Geochim. Cosmochim. Acta, 86, 88-102. [2] Mysen, B. O. (2010), Amer. Mineral., 95, 1807-1816. [3] O'Neil, J. R., and Truesdell, A. E. (1993), pp. 17-25 in Stable isotope geochemistry: A tribute to Samuel Epstein, (eds.: H. P. Taylor, J. R. O'Neil and I. R. Kaplan), The Geochemical Society, Calgary.

Fate of dissolved organic nitrogen in two stage trickling filter process.

Science.gov (United States)

Simsek, Halis; Kasi, Murthy; Wadhawan, Tanush; Bye, Christopher; Blonigen, Mark; Khan, Eakalak

2012-10-15

Dissolved organic nitrogen (DON) represents a significant portion of nitrogen in the final effluent of wastewater treatment plants (WWTPs). Biodegradable portion of DON (BDON) can support algal growth and/or consume dissolved oxygen in the receiving waters. The fate of DON and BDON has not been studied for trickling filter WWTPs. DON and BDON data were collected along the treatment train of a WWTP with a two-stage trickling filter process. DON concentrations in the influent and effluent were 27% and 14% of total dissolved nitrogen (TDN). The plant removed about 62% and 72% of the influent DON and BDON mainly by the trickling filters. The final effluent BDON values averaged 1.8 mg/L. BDON was found to be between 51% and 69% of the DON in raw wastewater and after various treatment units. The fate of DON and BDON through the two-stage trickling filter treatment plant was modeled. The BioWin v3.1 model was successfully applied to simulate ammonia, nitrite, nitrate, TDN, DON and BDON concentrations along the treatment train. The maximum growth rates for ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria, and AOB half saturation constant influenced ammonia and nitrate output results. Hydrolysis and ammonification rates influenced all of the nitrogen species in the model output, including BDON. Copyright © 2012 Elsevier Ltd. All rights reserved.

Dissolved inorganic nutrients and chlorophyll on the narrow continental shelf of Eastern Brazil

Directory of Open Access Journals (Sweden)

Gilmara Fernandes Eça

2014-03-01

Full Text Available The eastern Brazilian continental shelf is narrow and subject to the influence of a western boundary current system, presenting lower biological productivity than other regions. In this study, the distribution of water masses, dissolved inorganic nutrients, chlorophyll-a and total suspended solids (TSS on the inner shelf (< 35 m depth, between Itacaré and Canavieiras, eastern Brazil, is presented. Sampling surveys were carried out in March and August 2006 and March 2007. Tropical water (TW prevailed during March 2006 and August 2007 with the lower salinity waters (< 36 found in most samples taken in March 2007, reflecting the influence of continental outflow and rain in coastal waters. Low concentrations of dissolved inorganic nutrients and Chl-a found were typical of TW and results suggested that the inner shelf waters were depleted in dissolved inorganic nitrogen in August 2006 and March 2007, and in phosphate in March 2006, potentially affecting phytoplankton growth. Stratification of the water column was observed due to differences in dissolved nutrient concentrations, chlorophyll-a and TSS when comparing surface and bottom samples, possibly the result of a colder water intrusion and mixing on the bottom shelf and a deep chlorophyll maximum and/or sediment resuspension effect. Despite this stratification, oceanographic processes such as lateral mixing driven by the Brazil Current as well as a northward alongshore drift driven by winds and tides transporting Coastal Water can lead to an enhanced mixing of these waters promoting some heterogeneity in this oligotrophic environment.

CADDIS Volume 2. Sources, Stressors and Responses: Dissolved Oxygen - Detailed Conceptual Diagram

Science.gov (United States)

Introduction to the dissolved oxygen module, when to list dissolved oxygen as a candidate cause, ways to measure dissolved oxygen, simple and detailed conceptual model diagrams for dissolved oxygen, references for the dissolved oxygen module.

CADDIS Volume 2. Sources, Stressors and Responses: Dissolved Oxygen - Simple Conceptual Diagram

Science.gov (United States)

Introduction to the dissolved oxygen module, when to list dissolved oxygen as a candidate cause, ways to measure dissolved oxygen, simple and detailed conceptual model diagrams for dissolved oxygen, references for the dissolved oxygen module.

Cycling downwards - dissolved organic matter in soils

NARCIS (Netherlands)

Kaiser, K.; Kalbitz, K.

2012-01-01

Dissolved organic matter has been recognized as mobile, thus crucial to translocation of metals, pollutants but also of nutrients in soil. We present a conceptual model of the vertical movement of dissolved organic matter with soil water, which deviates from the view of a chromatographic stripping

Dissolved inorganic carbon, total alkalinity, pH, nutrients, and other variables collected from surface discrete observations using Niskin bottle and other instruments from R/V F. G. Walton Smith in the west coast of Florida within Gulf of Mexico from 2015-09-23 to 2015-09-24 (NCEI Accession 0157025)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains the surface discrete measurements of dissolved inorganic carbon, total alkalinity, pH and nutrients in the west coast of Florida near...

[Spectral characteristics of dissolved organic matter released during the metabolic process of small medusa].

Science.gov (United States)

Guo, Dong-Hui; Yi, Yue-Yuan; Zhao, Lei; Guo, Wei-Dong

2012-06-01

The metabolic processes of jellyfish can produce dissolved organic matter (DOM) which will influence the functioning of the aquatic ecosystems, yet the optical properties of DOM released by jellyfish are unknown. Here we report the absorption and fluorescence properties of DOM released by a medusa species Black fordia virginica during a 24 h incubation experiment. Compared with the control group, an obvious increase in the concentrations of dissolved organic carbon (DOC), absorption coefficient (a280) and total dissolved nitrogen (TDN) was observed in incubation group. This clearly demonstrated the release of DOM, chromophoric DOM (CDOM) and dissolved nutrients by B. virginica which feed on enough of Artemia sp. before the experiment. The increase in spectral slope ratio (SR) and decrease in humification index (HIX) indicated that the released DOM was less-humified and had relatively lower molecular weight. Parallel factor analysis (PARAFAC) decomposed the fluorescence matrices of DOM into three humic-like components (C1-C3) and one protein-like component (C4). The Fmax of two components (C2: 400 nm showed little changes. Thus, we suggested a zooplankton index (ZIX) to trace and characterize the DOM excreted by metabolic activity of zooplankton, which is calculated as the ratio of the sum of Fmax of all fluorescence components with the emission wavelength 400 nm.

Subcooled boiling effect on dissolved gases behaviour

International Nuclear Information System (INIS)

Zmitko, M.; Sinkule, J.; Linek, V.

1999-01-01

A model describing dissolved gasses (hydrogen, nitrogen) and ammonia behaviour in subcooled boiling conditions of WWERs was developed. Main objective of the study was to analyse conditions and mechanisms leading to formation of a zone with different concentration of dissolved gases, eg. a zone depleted in dissolved hydrogen in relation to the bulk of coolant. Both, an equilibrium and dynamic approaches were used to describe a depletion of the liquid surrounding a steam bubble in the gas components. The obtained results show that locally different water chemistry conditions can be met in the subcooled boiling conditions, especially, in the developed subcooled boiling regime. For example, a 70% hydrogen depletion in relation to the bulk of coolant takes about 1 ms and concerns a liquid layer of 1 μn surrounding the steam bubble. The locally different concentration of dissolved gases can influence physic-chemical and radiolytic processes in the reactor system, eg. Zr cladding corrosion, radioactivity transport and determination of the critical hydrogen concentration. (author)

High-performance liquid chromatographic characterization of dissolved organic matter from low-level radioactive waste leachates

International Nuclear Information System (INIS)

Caron, F.; Elchuk, S.; Walker, Z.H.

1996-01-01

Leachates from a waste degradation experiment, containing ∼700-3700 mg C/I of dissolved organic matter (DOM), were analyzed by high-performance liquid chromatography (HPLC) and liquid chromatography (LC), using various separation strategies. Scaling up of the separation scheme to a semi-preparative scale, suitable for hyphenated techniques, was also investigated. Separations with reversed-phase columns suggested that ∼70-93% of the DOM was hydrophilic, and ion-pair chromatography of this fraction showed the presence of several discrete compounds. Labile and non-labile complexes were formed by adding 60 Co radiotracer. Size-exclusion chromatography indicated that the DOM was primarily in the <1000-1500 Da molecular mass range. (author)

Dissolved organic nutrients and phytoplankton production in the Mandovi estuary and coastal waters of Goa

Digital Repository Service at National Institute of Oceanography (India)

Verlecar, X.N.

Total organic nitrogen (TON) and dissolved organic phosphorus (DOP) in the coastal and estuarine waters of Goa, India varied from 0.6 to 47.1 mu g-at N 1-1 and 0.12 to 3.49 mu g-at P l-1 respectively. The chlorophyll content of these waters...

Characterization of heavy metal desorption from road-deposited sediment under acid rain scenarios.

Science.gov (United States)

Zhao, Bo; Liu, An; Wu, Guangxue; Li, Dunzhu; Guan, Yuntao

2017-01-01

Road-deposited sediments (RDS) on urban impervious surfaces are important carriers of heavy metals. Dissolved heavy metals that come from RDS influenced by acid rain, are more harmful to urban receiving water than particulate parts. RDS and its associated heavy metals were investigated at typical functional areas, including industrial, commercial and residential sites, in Guangdong, Southern China, which was an acid rain sensitive area. Total and dissolved heavy metals in five particle size fractions were analyzed using a shaking method under acid rain scenarios. Investigated heavy metals showed no difference in the proportion of dissolved fraction in the solution under different acid rain pHs above 3.0, regardless of land use. Dissolved loading of heavy metals related to organic carbon content were different in runoff from main traffic roads of three land use types. Coarse particles (>150μm) that could be efficiently removed by conventional street sweepers, accounted for 55.1%-47.1% of the total dissolved metal loading in runoff with pH3.0-5.6. The obtained findings provided a significant scientific basis to understand heavy metal release and influence of RDS grain-size distribution and land use in dissolved heavy metal pollution affected by acid rain. Copyright © 2016. Published by Elsevier B.V.

Method to Estimate the Dissolved Air Content in Hydraulic Fluid

Science.gov (United States)

Hauser, Daniel M.

2011-01-01

In order to verify the air content in hydraulic fluid, an instrument was needed to measure the dissolved air content before the fluid was loaded into the system. The instrument also needed to measure the dissolved air content in situ and in real time during the de-aeration process. The current methods used to measure the dissolved air content require the fluid to be drawn from the hydraulic system, and additional offline laboratory processing time is involved. During laboratory processing, there is a potential for contamination to occur, especially when subsaturated fluid is to be analyzed. A new method measures the amount of dissolved air in hydraulic fluid through the use of a dissolved oxygen meter. The device measures the dissolved air content through an in situ, real-time process that requires no additional offline laboratory processing time. The method utilizes an instrument that measures the partial pressure of oxygen in the hydraulic fluid. By using a standardized calculation procedure that relates the oxygen partial pressure to the volume of dissolved air in solution, the dissolved air content is estimated. The technique employs luminescent quenching technology to determine the partial pressure of oxygen in the hydraulic fluid. An estimated Henry s law coefficient for oxygen and nitrogen in hydraulic fluid is calculated using a standard method to estimate the solubility of gases in lubricants. The amount of dissolved oxygen in the hydraulic fluid is estimated using the Henry s solubility coefficient and the measured partial pressure of oxygen in solution. The amount of dissolved nitrogen that is in solution is estimated by assuming that the ratio of dissolved nitrogen to dissolved oxygen is equal to the ratio of the gas solubility of nitrogen to oxygen at atmospheric pressure and temperature. The technique was performed at atmospheric pressure and room temperature. The technique could be theoretically carried out at higher pressures and elevated

Natural gas adsorption on coal in anhydrous and in water saturated conditions: study of the adsorbed quantities and of the isotopic fractionation

International Nuclear Information System (INIS)

Caja, M.

2000-02-01

In order to understand the influence of adsorption in the migration of natural gas in sedimentary basins. we have developed an experimental device to measure the quantity of gas adsorbed on organic matter. We quantify the isotopic and chemical fractionation due to adsorption of natural gas on coal at representative gas field conditions (20 - 200 deg C and 1 - 1000 bar). These effects are investigated for gas / solid systems and for gas dissolved in water/water saturated solid systems. The solid sample considered in this work is a natural coal of Carboniferous age, taken from a mine in Lorraine, France. Its maturity corresponds to the end of the diagenesis zone. A first set of high pressure methane adsorption experiments on dry coal are compared with measurements done by another laboratory on the same solid. This allowed us to validate the experimental procedure. This measurements performed in the presence of water have shown that methane adsorption is significant even in presence of water. We have developed a simple adsorption model (Langmuir model in which fugacity is used in stead of partial pressure) in order to represent this phenomena. For a depth profile we compare the part of methane adsorbed on sedimentary rocks organic matter to methane dissolved in pore water. A second set of experiments realised on a multicomponent gas (C1, C2, C3, C4, CO 2 ) shows a preferential adsorption of carbon dioxide, but no significant fractionation on hydrocarbon gases of the mixture has been observed. Adsorption experiments of methane on dry medium and on water saturated medium yield on the same result: adsorption equilibrium do not induce a significant isotopic fractionation between 13 CH 4 and 12 CH 4 . However, we observe a significant fractionation during gas desorption. The interpretation is that we are not at equilibrium and diffusion phenomena is superimposed on adsorption. From this study two important geological consequences can be drawn. First. for rocks containing

Dissolved inorganic carbon, total alkalinity, temperature, salinity and other variables collected from profile and discrete sample observations using CTD, Niskin bottle, and other instruments from NOAA Ship HI'IALAKAI and NOAA Ship OSCAR ELTON SETTE in the U.S. Pacific Reefs from 2012-03-02 to 2014-05-05 (NCEI Accession 0131502)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This archival package contains data from samples collected and analyzed for total alkalinity (TA) and dissolved inorganic carbon (DIC). From these constituents,...

Phytotoxic activity of crude aqueous extracts and fractions of young leaves of Sapindus saponaria L. (Sapindaceae

Directory of Open Access Journals (Sweden)

Patrícia Umeda Grisi

2013-03-01

Full Text Available The aim of this study was to evaluate the phytotoxic potential of aqueous extract of young leaves of Sapindus saponaria L. (soapberry on the diaspore germination and seedling growth Lactuca sativa L. (lettuce and Allium cepa L. (onion, as well as to determine, by bioassay-guided fractioning, whether the fractionated extracts of those leaves are phytotoxic to Triticum aestivum L. (wheat coleoptiles. The aqueous extract was prepared using 100 g of dried plant material dissolved in 1000 ml of distilled water, resulting in a concentration of 10.0%. Distilled water was added in order to obtain dilutions of 7.5%, 5.0%, and 2.5%. The extraction was carried out with young leaves (in powder form and organic solvents of various polarities. We fractioned the ethyl acetate extract using column chromatography. The phytotoxic potential of the aqueous extract of young leaves S. saponaria varied according to the receiving species and the concentration-dependent inhibitory effect. The ethyl acetate extract, specifically fraction 6 (57-70, had the greatest inhibitory effect on the elongation of wheat coleoptiles, indicating that the compounds responsible for the phytotoxic effect reside within this fraction.

Feasibility of fractionating MIBI cold kits for cost reduction

Energy Technology Data Exchange (ETDEWEB)

Penglis, S.; Tsopelas, C. [Royal Adelaide Hospital. SA (Australia)

1998-06-01

Full text: Recently {sup 99m}Tc-MIBI become the first 99mTc-labelled myocardial perfusion imaging agent commercially available in Australia. After labelling each vial is sufficient for three to four patient doses. However, it becomes very expensive when only a single patient dose is required (up to $350 per dose). Our goal in this study was to subdivide the MIBI kit into fractions to establish the stability of these split kits. If successful, this would reduce the expense and make the product more cost-effective. After dissolving the Iyophilised ingredients of a MIBI vial with 5 mL of N2-purged normal saline, 1 mL aliquots of the resultant solution were dispensed into N2-filled vials under aseptic conditions. The vials were then stored frozen at -70 deg C. 99mTc-MIBI was prepared by the addition of 2 GBq of {sup 99m}Tc-pertechnetate in I mL of normal saline to the fractionated kit, followed by heating at 100 deg C for 10 minutes at 0, 2, 4 and 8 weeks post-fractionation. The product was allowed to cool before testing for radiochemical purity (RCP) for up to six hours post-labelling. The RCP of each vial was determined using aluminium oxide coated aluminium TLC strips (Merck) run in 100% ethanol. Over the eight-week evaluation period RCP was maintained at 94.2 + 1.3% over six hours (n = 16), which is greater than the minimum recommended RCP (90%) for patient use. These results show that fractionation of MIBI cold kits and sub-frozen storage under an N{sub 2} atmosphere provides a stable and economical multidose product. Using this method the cost of a single patient dose can be reduced considerably from $350, even allowing for the labour involved in the fractionation

Feasibility of fractionating MIBI cold kits for cost reduction

International Nuclear Information System (INIS)

Penglis, S.; Tsopelas, C.

1998-01-01

Full text: Recently 99m Tc-MIBI become the first 99mTc-labelled myocardial perfusion imaging agent commercially available in Australia. After labelling each vial is sufficient for three to four patient doses. However, it becomes very expensive when only a single patient dose is required (up to $350 per dose). Our goal in this study was to subdivide the MIBI kit into fractions to establish the stability of these split kits. If successful, this would reduce the expense and make the product more cost-effective. After dissolving the Iyophilised ingredients of a MIBI vial with 5 mL of N2-purged normal saline, 1 mL aliquots of the resultant solution were dispensed into N2-filled vials under aseptic conditions. The vials were then stored frozen at -70 deg C. 99mTc-MIBI was prepared by the addition of 2 GBq of 99m Tc-pertechnetate in I mL of normal saline to the fractionated kit, followed by heating at 100 deg C for 10 minutes at 0, 2, 4 and 8 weeks post-fractionation. The product was allowed to cool before testing for radiochemical purity (RCP) for up to six hours post-labelling. The RCP of each vial was determined using aluminium oxide coated aluminium TLC strips (Merck) run in 100% ethanol. Over the eight-week evaluation period RCP was maintained at 94.2 + 1.3% over six hours (n = 16), which is greater than the minimum recommended RCP (90%) for patient use. These results show that fractionation of MIBI cold kits and sub-frozen storage under an N 2 atmosphere provides a stable and economical multidose product. Using this method the cost of a single patient dose can be reduced considerably from $350, even allowing for the labour involved in the fractionation

Removal of Dissolved Salts and Particulate Contaminants from Seawater: Village Marine Tec., Expeditionary Unit Water Purifier, Generation 1

Science.gov (United States)

The EUWP was developed to treat challenging water sources with variable turbidity, chemical contamination, and very high total dissolved solids (TDS), including seawater, during emergency situations when other water treatment facilities are incapacitated. The EUWP components incl...