bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improvement of a sensitive enzyme-linked immunosorbent assay for screening estrogen receptor binding activity
Authors: Koda Tomoko , Soya Yoshihiro , Negishi Harumi , Shiraishi Fujio , Morita MAsatoshi 
Published: March 2010

Abstract
A competitive enzyme-linked immunosorbent assay (ELISA) with estrogen receptor (a) and a fluorescence depolarization method with Full-Range Beacon were examined as estrogen receptor binding assays to prescreen endocrine-disrupting chemicals (EDCs). In this study, because it is difficult to measure the receptor binding ability of sparingly water-soluble chemicals using these methods, the competitive enzyme immunoassay was further modified for improved sensitivity by changing the operational parameters, such as receptor concentration, ligand concentration, and the reaction temperature. The method was applied to 10 test chemicals, including alkylphenols and bisphenol A (BPA). The diethylstilbestrol (DES) relative binding affinity (RBA) of ELISA kit was set equal to 1 (RBA = IC50/IC50 of DES). The RBAs of BPA, 4-nonylphenol (p-NP), and 4-t-octylphenol (p-t-OP) are 5386, 8619, and 8121 before using the improved competitive enzyme immunoassay and 883, 699, and 2832 using improved it respectively. Mixtures of BPA, p-NP, and p-t-OP gave results that the estrogen binding affinities of these chemicals are additive or slightly more than additive.
Concentrations and enantiomer fractions of organochlorine compounds in baltic species hit by reproductive impairment
Authors: Wiberg Karin , Bergman Anders , Olsson Mats , Roos Anna , Blomkvist Gun , Haglund Peter 
Published: March 2010

Abstract
Concentrations and enantiomer fractions (EFs) of organochlorine compounds (OCs) were determined in tissues of gray seal (Halichoerus grypus) and salmon (Salmo salar) originating from the Baltic Sea. The selected seal specimens ranged from starved to unstarved animals, and some of them suffered from a disease complex, while the salmon samples originated from individuals, which were known to produce offspring with and without the M74 syndrome. Significant differences in residue levels and EFs were found between seal groups but not between M74 salmon and non-M74 salmon. The relations between chemical and biological variables of seal samples were investigated with multivariate statistics. Poor health status correlated strongly with age, while bad nutrition condition was associated mainly with high pollution loads and distinctively nonracemic chiral OC compositions. High biotransformation rate (as indicated by fraction of chlordane metabolites in relation to total level of chlordanes) was also associated with large deviations from racemic values and high contaminant levels.
Using the dioxin receptor–calux in vitro bioassay to screen marine harbor sediments for compounds with a dioxin-like mode of action
Authors: Stronkhorst Joost , Leonards Pim , Murk Albertinka J. 
Published: March 2010

AbstractThe presence of dioxin-like compounds in sediments from harbors and reference sites along the Dutch coast was investigated using the dioxin receptor-chemically activated luciferase gene expression (DR-CALUX) bioassay. The DR-CALUX response varied between 0.2 and 136 ng/kg dry weight expressed in units of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) toxic equivalency quotients (TEQ). The highest CALUX-TEQ values (&gt;50 ng TEQ/kg dry wt) were found in sediments from the center of the Port of Rotterdam and from the North Sea canal near Amsterdam. The DR-CALUX activity of harbor sediments was classified by setting guideline values. None of the 257 harbor sediment samples investigated exceeded the maximum value of 1,000 ng TEQ/kg, while 94% of the samples fail the target value of 2 ng TEQ/kg. Threshold values (25 and 50 ng TEQ/kg) are intended as pass/fail criteria for offshore disposal of dredged material and were exceeded in 12 and 3% of the samples, respectively. DR-CALUX response did not always match with contamination of polychlorinated biphenyls (PCBs) as determined in bulk sediments (∑7-PCB ranging from &lt;1 to 456 μg/kg dry wt). Concentrations of planar PCBs, polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinateddibenzofuranes (PCDFs), polybrominated biphenyls (PBBs), and polybrominated-diphenylethers (PBDEs) were determined in 20 selected sediment extracts. On average, PCDD/Fs explained 50% of the DR-CALUX activity and planar PCBs 6%. Further research is needed to elucidate the unexplained part of the DR-CALUX response. The DR-CALUX is a highly sensitive and reproducible bioassay that can usefully complement standard PCB analysis, improving the hazard assessment of the disposal of dredged material in the North Sea.
The concept of persistence as applied to metals for aquatic hazard identification
Authors: Skeaff James M. , Dubreuil Alain A. , Brigham Sarah I. 
Published: March 2010

Abstract
The criteria persistence (P), bioaccumulation (B), and toxicity (T) are applied by domestic and international regulators and modelers to the hazard identification of chemical substances, including metals and metalloids, that may present harm to the environment. In this paper, we critically examine the literature to determine the weight of evidence for the application of water column partition half-times as a surrogate for the persistence criterion in the aquatic hazard identification of metals and metal compounds. Dissolved metals such as Fe, Mn, Cu, Pb, Co, Cs, Hg, and Zn, as well as the metalloids As and Se, tend to partition from the water column by adsorption onto sinking particulates, with reported and calculated partition half-times in the range 4 to 30 d, with outliers of 0.07 and 280 d. Within freshwater lakes, values of t1/2 for the transition metals Cr, Mn, Fe, Co, and Cu averaged about 10 d, while those for the nontransition metals Sr, Zn, Cs, and Hg and the metalloids As and Se varied up to 55 d. These data are consistent with the well-established complexing properties of the transition metals, which are significantly greater compared to the nontransition metals and the metalloids. While the considerable variations in the literature at present preclude the use of metal partition half-times in aquatic hazard identification, the surrogate for the persistence criterion could be the partition half-time of the bioavailable fraction of the total dissolved metal concentration as determined in a laboratory protocol under standardized conditions.
Degradation of chlorpyrifos, fenamiphos, and chlorothalonil alone and in combination and their effects on soil microbial activity
Authors: Singh Brajesh Kumar , Walker Allan , Wright Denis J. 
Published: March 2010

Abstract
The effects of repeated application and of combinations of pesticides on their degradation rates in soil and on some soil microbial properties were studied. Repeated application of chlorpyrifos did not modify its degradation rate, whereas repeated applications of fenamiphos and chlorothalonil suppressed their own rates of degradation. When applied in combination, the presence of chlorothalonil reduced the degradation rate of both chlorpyrifos and fenamiphos, and the half-life of chlorothalonil was extended in the presence of chlorpyrifos. The dynamics of residues of the major metabolites of the different compounds were also affected by the pesticide combinations and, particularly, by the presence of chlorothalonil. The measured soil microbial parameters (enzyme activities and total microbial biomass) were stable in the pesticide-free control soils throughout the 90-d incubation period, but they were all adversely affected by the presence of chlorothalonil in the soil. The effects from fenamiphos or chlorpyrifos on the soil microbial characteristics were either very small or insignificant.
Investigation of an onsite wastewater treatment system in sandy soil: Sorption and biodegradation of linear alkylbenzene sulfonate
Authors: Doi Jon , Marks Kay H. , Decarvalho Alvaro J. , McAvoy Drew C. , Nielsen Allen M. , Kravetz Louis , Cano Manuel L. 
Published: March 2010

Abstract
The objective of this work was to determine the sorptive and biodegradable characteristics of linear alkylbenzene sulfonate (LAS) in a soil below a Florida, USA, septic system drainfield. Three distinct soil samples were collected from the septic system drainfield study site. These soils were used in laboratory sorption and biodegradation studies. Different concentrations of LAS were added, in radiolabeled and unlabeled forms, to a series of test vessels that contained upgradient groundwater and the soils collected from the study site. The sorption test was designed to determine the partitioning of LAS between groundwater and soil in each sample. Results indicated that the sorption distribution coefficient (Kd) decreased from 4.02 to 0.43 L/kg and that the rate of ultimate biodegradation (first-order rate constant, k1) decreased from 2.17 to 0.08/d with increasing distance (0.7–1.2 m vertically below ground surface [BGS] and 0 to 6.1 m horizontally) from the drainfield. The three soils showed 49.8 to 83.4% LAS mineralization (percentage of theoretical CO2) over 45- or 59-d test periods. These results demonstrate that subsurface soils in this system have the potential to sorb and biodegrade LAS.
Effect of ethanol and methyl-Tert-butyl ether on monoaromatic hydrocarbon biodegradation: Response variability for different aquifer materials under various electron-accepting conditions
Authors: Ruiz-Aguilar Graciela M. L. , Fernandez-Sanchez Jose M. , Kane Staci R. , Kim Donguk , Alvarez Pedro J. J. 
Published: March 2010

Abstract
Aquifer microcosms were used to determine how ethanol and methyl-tert-butyl ether (MtBE) affect monoaromatic hydrocarbon degradation under different electron-accepting conditions commonly found in contaminated sites experiencing natural attenuation. Response variability was investigated by using aquifer material from four sites with different exposure history. The lag phase prior to benzene, toluene, ethylbenzene, and xylenes (BTEX) and ethanol degradation was typically shorter in microcosms with previously contaminated aquifer material, although previous exposure did not always result in high degradation activity. Toluene was degraded in all aquifer materials and generally under a broader range of electron-accepting conditions compared to benzene, which was degraded only under aerobic conditions. The MtBE was not degraded within 100 d under any condition, and it did not affect BTEX or ethanol degradation patterns. Ethanol was often degraded before BTEX compounds and had a variable effect on BTEX degradation as a function of electron-accepting conditions and aquifer material source. An occasional enhancement of toluene degradation by ethanol occurred in denitrifying microcosms with unlimited nitrate; this may be attributable to the fortuitous growth of toluene-degrading bacteria during ethanol degradation. Nevertheless, experiments with flow-through aquifer columns showed that this beneficial effect could be eclipsed by an ethanol-driven depletion of electron acceptors, which significantly inhibited BTEX degradation and is probably the most important mechanism by which ethanol could hinder BTEX natural attenuation. A decrease in natural attenuation could increase the likelihood that BTEX compounds reach a receptor as well as the potential duration of exposure.
Degradation and persistence of metolachlor in soil: Effects of concentration, soil moisture, soil depth, and sterilization
Authors: Rice Pamela J. , Anderson Tood A. , Coats Joel R. 
Published: March 2010

Abstract
The present study evaluated the influence of soil depth, soil moisture, and concentration on the persistence and degradation of metolachlor in soil. Greater percentages of metolachlor persisted in subsurface soils than in surface soil regardless of the soil moisture or initial herbicide concentration. Larger quantities of bound residues and extractable degradation products were found in the surface soils as a result of the increased soil sorption and biodegradation of metolachlor associated with the surface soil, which had more organic matter. Saturated soil favored the dissipation of metolachlor and the formation of soil-bound residues. Significantly greater quantities of a dechlorinated metabolite were measured in the saturated surface soil compared to the unsaturated soil. Mineralization of metolachlor to CO2 and volatilization of metolachlor or metolachlor degradates was minimal in surface and subsurface soils at both soil moistures and herbicide concentrations. Increased metolachlor concentrations did not inhibit microbial activity; however, the greater rate of application did result in the reduced percentage of applied [14C]metolachlor that was bound to surface or subsurface soil. A significant reduction in the quantity of extractable metolachlor degradates and unextractable soilbound residues in sterile soil revealed the significance of biodegradation to the dissipation of metolachlor in soil.
Modeling the toxicity of polar and nonpolar narcotic compounds to luminescent bacterium Shk1
Authors: Ren Shijin , Frymier Paul D. 
Published: March 2010

Abstract
Luminescent bacterium Shk1 was created for the purpose of testing and screening the toxicity of activated sludge wastewater treatment plant influent to avoid toxic shock to the wastewater treatment plant microorganisms. The toxicity of a number of organic compounds was tested using an assay employing Shk1. Because these compounds exhibit toxicity by mechanisms of both polar and nonpolar narcosis, their toxicity cannot be properly modeled together using a quantitative structure-activity relationship model based on the logarithm of the octanol-water partition coefficient (log Kow). A solvation parameter model was developed to describe and predict the nonspecific (i.e., polar and nonpolar narcosis) toxicity of organic compounds to Shk1, which does not depend on the discrimination between polar and nonpolar narcotic compounds. The statistically significant model descriptors were the McGowan's characteristic volume (VX) and the hydrogen-bond basicity (∑βH). The model was similar to the solvation parameter model developed for Vibrio fischeri, but it did not include an excess molar refraction (R) term.
Biological availability of traffic-related platinum-group elements (palladium, platinum, and rhodium) and other metals to the zebra mussel (Dreissena polymorpha) in water containing road dust
Authors: Zimmermann Sonja , Alt Friedrich , Messerschmidt Jürgen , von Bohlen Alex , Taraschewski Horst , Sures Bernd 
Published: March 2010

Abstract
The uptake and bioaccumulation of 15 road dust metals by the zebra mussel (Dreissena polymorpha) were investigated in laboratory exposure studies with emphasis on the traffic-related platinum-group elements (PGEs) palladium (Pd), platinum (Pt), and rhodium (Rh). The biological availability of the metals may depend on water characteristics, so the mussels were maintained in two types of water: nonchlorinated tap water and humic water of a bog lake, both of which contained dust of a moderately frequented road. After an exposure period of 26 weeks, soft tissues of the mussels were freeze-dried and analyzed for the metals. The metal concentrations in the mussel soft tissue ranged from several hundred micrograms per gram (e.g., for iron [Fe]) to less than 10 ng/g (for PGEs). Metal uptake from the road dust by the mussels was found for the PGEs and silver (Ag), bismuth (Bi), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), Fe, lead (Pb), and antimony (Sb). After maintenance of mussels in road dust-contaminated tap water, bioaccumulation factors (BAF 5 (cexposed mussels - ccontrol mussels)/ctotal metal, water; where c is concentration) decreased in the following order: Cu &gt; Cd &gt; Ag &gt; Pd &gt; Sb &gt; Pb &gt; Fe &gt; Pt &gt; Rh. The biological availability of most metals was enhanced by humic water as compared to tap water. Our results show a hitherto unrecognized high availability of Pd for the mussels. Thus, this metal should be monitored more intensively in the environment to assess its distribution in the biosphere.
The effect of 17β-Estradiol on the gonopodial development and sexual activity of Gambusia holbrooki
Authors: Doyle Christopher J. , Lim Richard P. 
Published: March 2010

Abstract
Many chemicals have recently been demonstrated to possess estrogenic activity and may potentially interfere with normal sexual development. In the present study, we quantified the effects of waterborne exposure to 17β-estradiol on the gonopodial development and sexual activity of male eastern mosquitofish (Gambusia holbrooki). Juvenile males were exposed during the period of sexual maturation to nominal concentrations of 20, 100, and 500 ng/L of 17β-estradiol and a solvent control (0.00003% w/v ethanol) for 84 d under continuous-flow conditions. Following exposure, significant differences were found among the test treatments with respect to gonopodial length and degree of gonopodial elongation of the fish. Sexual activity, measured as the number of approaches and copulatory attempts made by the exposed males to nonexposed females, also significantly decreased with increasing concentrations of 17β-estradiol. Because the degree of gonopodial maturation and frequency of sexual activity are important characteristics for the reproductive success of male mosquitofish, it is suggested that these traits provide sensitive and ecologically relevant endpoints for assessing estrogenic activity under both laboratoryand field-exposure conditions.
Gene expression in Xenopus embryos after methylmercury exposure: A search for molecular biomarkers
Authors: Monetti Claudio , Vigetti Davide , Prati Mariangela , Sabbioni Enrico , Bernardini Giovanni , Gornati Rosalba 
Published: March 2010

Abstract
Mercury is a major issue in environmental health, as it can be biotransformed to methylmercury, accumulate into aquatic organisms, and enter the food chain. Therefore, we searched for molecular markers for methylmercury exposure comparing, by differential display, exposed Xenopus embryos to controls. We found two genes whose expression is completely inhibited by CH3HgCl, and we propose them as biomarkers of exposure. The first transcript appears to be a novel gene, with a short region similar to the human iron-sulfur subunit of succinate dehydrogenase. The second gene presents a high similarity with the human homeodomain-interacting protein kinase 3 (HIPK3), a protein that is known to be involved in the apoptotic signaling pathway. These molecular biomarkers could be used to detect very early effects of the metal; furthermore, they could be useful in understanding the molecular mechanisms of mercury toxicity.
Ecological effects of an anionic C12–15 AE-3S alkylethoxysulfate surfactant in outdoor stream mesocosms
Authors: Lizotte Richard E. , Dorn Philip B. , Steinriede R. Wade , Wong Diana C. L. , Odgers John H. 
Published: March 2010

AbstractThe ecological assessment of a C12–15 AE-3S linear alkylethoxysulfate (AES) anionic surfactant to invertebrates, fish, periphyton, and an aquatic macrophyte was conducted in a 30-d outdoor stream mesocosm study with five replicated concentrations and controls. Alkylethoxysulfate structural integrity and exposure concentrations were maintained during the 30-d treatment period, with average measured concentrations of 0.7, 1.27, 2.2, 4.31, and 10.18 mg/L. No effects were observed on the aquatic macrophyte Myriophyllum aquaticum at the highest concentration tested. A sevenfold increase in periphyton biomass at 10.18 mg/L was observed relative to controls primarily because of increases in density of the filamentous alga Mougeotia sp. Densities of the invertebrates Annelida (Stylaria), Amphipoda, Copepoda, Trichoptera (Hydropsychidae), Cladocera, and Diptera (Chironomidae) significantly decreased in streams treated with AES at 10.18 mg/L. Densities of drifting invertebrates were not observed to be affected at any concentration tested. Reproduction of Pimephales promelas significantly decreased at 1.27 mg/L and growth of juvenile Lepomis macrochirus was significantly affected at 4.31 mg/L. Multivariate cluster analysis and nonmetric multidimensional scaling ordination showed distinct structural effects on the invertebrate communities in the streams treated with AES at 10.18 mg/ L compared to the control and streams treated at &lt;10.18 mg/L through the 30-d treatment. Convergence of the communities treated at 10.18 mg/L toward control communities in the ordination suggests recovery in these communities after termination of surfactant treatment. The results from this study support an ecosystem value of &gt;2.0 mg/L, and indicate that the conservative Dutch risk assessment for AESs has at least a fivefold margin of safety.
Analysis of arsenic bioavailability in contaminated soils
Authors: Turpeinen Riina , Virta Marko , Häggblom Max M. 
Published: March 2010

Abstract
The bioavailable arsenic (As) content of contaminated soils was determined by joint analyses of acid-soluble, total water-soluble, and biovailable As by using a luminescent bacterial sensor, Escherichia coli MC1061(pTOO31). According to the results of this study, a significant positive correlation was found between the concentration of total water-soluble As and the bioavailability of As. However, the bioavailability of As in soil varied between sampling sites and was not equal when compared to the concentration of total water-soluble As; bioavailable As was 3 to 77% of total water-soluble As in soil. Our experiments also showed that aging and sequestration of As occurs in contaminated soils and As compounds thus become progressively less bioavailable with time. As a consequence, the bioavailability and toxicity of As should be considered when evaluating the ecological risks of contaminated soils.
Development and application of a generalized physiologically based pharmacokinetic model for multiple environmental contaminants
Authors: Cahill Thomas M. , Cousins Ian , Mackay Donald 
Published: March 2010

AbstractThe pharmacological disposition of four environmental contaminants resulting from acute and chronic exposure regimes is simulated using a general physiologically based pharmacological (PBPK) model. The model, which is detailed in supporting materials, is mechanistic in structure and relies on available physical-chemical partitioning and reactivity data, but experimental partitioning and absorption efficiency data can be used to refine the parameters. It is designed to complement environmental fate models, thus linking chemical emission rates with environmental and physiological behavior as part of the larger environmental risk assessment process. The model is illustratively applied to inhaled styrene and trichloroethene as well as ingested dibutyl phthalate and di(2-ethylhexyl) phthalate. The phthalate simulations include the corresponding monoester and conjugated monoester as metabolites. Tissue concentrations for each of the chemicals and metabolites are simulated for acute, occupational, and environmental exposure regimes. The same model is used for all chemicals and exposure regimes with only the physical-chemical properties, reaction rates, and exposure estimates being changed.