bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chemical structure-based predictive model for methanogenic anaerobic biodegradation potential
Authors: Meylan William , Boethling Robert , Aronson Dallas , Howard Philip , Tunkel Jay 
Published: August 2007

Abstract
Many screening-level models exist for predicting aerobic biodegradation potential from chemical structure, but anaerobic biodegradation generally has been ignored by modelers. We used a fragment contribution approach to develop a model for predicting biodegradation potential under methanogenic anaerobic conditions. The new model has 37 fragments (substructures) and classifies a substance as either fast or slow, relative to the potential to be biodegraded in the “serum bottle” anaerobic biodegradation screening test (Organization for Economic Cooperation and Development Guideline 311). The model correctly classified 90, 77, and 91% of the chemicals in the training set (n = 169) and two independent validation sets (n = 35 and 23), respectively. Accuracy of predictions of fast and slow degradation was equal for training-set chemicals, but fast-degradation predictions were less accurate than slow-degradation predictions for the validation sets. Analysis of the signs of the fragment coefficients for this and the other (aerobic) Biowin© models suggests that in the context of simple group contribution models, the majority of positive and negative structural influences on ultimate degradation are the same for aerobic and methanogenic anaerobic biodegradation.
Effects of methylmercury on reproduction in American kestrels
Authors: Albers Peter H. , Koterba Michael T. , Rossmann Ronald , Link William A. , French John B. , Bennett Richard S. , Bauer Wayne C. 
Published: August 2007

AbstractSixty breeding pairs of captive American kestrels (Falco sparverius) were exposed to a range of sublethal dietary concentrations of mercury (Hg), in the form of methylmercuric chloride, and their subsequent reproduction was measured. Egg production, incubation performance, and the number and percent of eggs hatched decreased markedly between 3.3 and 4.6 mg/kg dry weight of Hg (1.2 and 1.7 mg/kg wet wt), in the diet. The number of fledglings and the percent of nestlings fledged were reduced markedly at 0.7 mg/kg dry weight (0.3 mg/kg wet wt) and declined further between 2 and 3.3 mg/kg dry weight (0.7 and 1.2 mg/kg wet wt). Dietary concentrations of ⩾4.6 mg/kg dry weight (1.7 mg/kg wet wt) were associated with total fledging failure. The estimated decline in fledged young per pair (24%, Bayesian regression) for kestrels consuming 0.7 mg/kg dry weight (0.3 mg/kg wet wt) raises concerns about population maintenance in areas subject to high inputs of anthropogenic Hg. Mercury concentrations in 20 second-laid eggs collected from all groups were related to dietary concentrations of Hg, and the Hg concentrations in 19 of these eggs were related to eggs laid and young fledged. Concentrations of Hg in eggs from the highest diet group (5.9 mg/kg dry wt; 2.2 mg/kg wet wt) were higher than egg concentrations reported for either wild birds or for captive birds (nonraptors) fed dry commercial food containing 5 mg/kg methylmercury. Accumulation ratios of Hg from diets to eggs were higher than those reported for feeding studies with other species.
Supercritical carbon dioxide extraction as a predictor of polycyclic aromatic hydrocarbon bioaccumulation and toxicity by earthworms in manufactured-gas plant site soils
Authors: Kreitinger Joseph P. , Quĩones-Rivera Antonio , Neuhauser Edward F. , Alexander Martin , Hawthorne Steven B. 
Published: August 2007

AbstractThe toxicity and uptake of polycyclic aromatic hydrocarbons (PAHs) by earthworms were measured in soil samples collected from manufactured-gas plant sites having a wide range in PAH concentrations (170–42,000 mg/kg) and soil characteristics. Samples varied from vegetated soils to pure lampblack soot and had total organic carbon contents ranging from 3 to 87%. The biota-soil accumulation factors (BSAFs) observed for individual PAHs in field-collected earthworms (Aporrectodea caliginosa) were up to 50-fold lower than the BSAFs predicted using equilibrium-partitioning theory. Acute toxicity to the earthworm Eisenia fetida was unrelated to total PAH concentration: Mortality was not observed in some soils having high concentrations of total PAHs (&gt;42,000 mg/kg), whereas 100% mortality was observed in other soils having much lower concentrations of total PAHs (1,520 mg/kg). Instead, toxicity appeared to be related to the rapidly released fraction of PAHs determined by mild supercritical CO2 extraction (SFE). The results demonstrate that soils having approximately 16,000 mg rapidly released total PAH/kg organic carbon can be acutely toxic to earthworms and that the concentration of PAHs in soil that is rapidly released by SFE can estimate toxicity to soil invertebrates.
Prediction of lethal/effective concentration/dose in the presence of multiple auxiliary covariates and components of variance
Authors: Gutreuter Steve , Boogaard Michael A. 
Published: August 2007

AbstractPredictors of the percentile lethal/effective concentration/dose are commonly used measures of efficacy and toxicity. Typically such quantal-response predictors (e.g., the exposure required to kill 50% of some population) are estimated from simple bioassays wherein organisms are exposed to a gradient of several concentrations of a single agent. The toxicity of an agent may be influenced by auxiliary covariates, however, and more complicated experimental designs may introduce multiple variance components. Prediction methods lag examples of those cases. A conventional two-stage approach consists of multiple bivariate predictions of, say, medial lethal concentration followed by regression of those predictions on the auxiliary covariates. We propose a more effective and parsimonious class of generalized nonlinear mixed-effects models for prediction of lethal/effective dose/concentration from auxiliary covariates. We demonstrate examples using data from a study regarding the effects of pH and additions of variable quantities 2',5'-dichloro-4'-nitrosalicylanilide (niclosamide) on the toxicity of 3-trifluoromethyl-4-nitrophenol to larval sea lamprey (Petromyzon marinus). The new models yielded unbiased predictions and root-mean-squared errors (RMSEs) of prediction for the exposure required to kill 50 and 99.9% of some population that were 29 to 82% smaller, respectively, than those from the conventional two-stage procedure. The model class is flexible and easily implemented using commonly available software.
Comparison of short-term chronic and chronic silver toxicity to fathead minnows in unamended and sodium chloride-amended waters
Authors: Naddy Rami B. , Rehner Anita B. , McNerney Gina R. , Gorsuch Joseph W. , Kramer James R. , Wood Chris M. , Paquin Paul R. , Stubblefield William A. 
Published: August 2007

AbstractThe chronic (early life stage [ELS]) and short-term chronic (STC) toxicity of silver (as silver nitrate) to fathead minnows (FHM) was determined concurrently in flow-through exposures (33 volume additions/d). Paired ELS (∼30 d) and STC (7 d) studies were conducted with and without the addition of 60 mg/L Cl (as NaCl). The paired studies in unamended water were later repeated using standard flow conditions (9 volume additions/d). The purpose of the paired studies was to determine if short-term chronic endpoints can be used to predict effects in ELS studies. For each experiment, a “split-chamber” design (organisms were held in a common exposure chamber) allowed the direct comparison between short-term and chronic exposures. It appeared that the chronic toxicity of silver was mitigated to some extent by NaCl addition. The maximum acceptable toxicant concentration for growth in the ELS study was 0.53 μg dissolved Ag/L under standard flow conditions. Early life stage and STC endpoints in all three studies typically agreed within a factor of two. Whole-body sodium and silver concentrations measured in individual fathead minnows during these studies showed an increase in silver body burdens and a decrease in sodium concentration. These results indicate that the STC study could be used as a surrogate test to estimate chronic toxicity and that the mechanism of chronic silver toxicity may be the same as for acute toxicity.
Orally administered bisphenol a in rainbow trout (Oncorhynchus mykiss): Estrogenicity, metabolism, and retention
Authors: Bjerregaard Poul , Andersen Sidsel B. , Pedersen Knud L. , Pedersen Søren N. , Korsgaard Bodil 
Published: August 2007

Abstract
The estrogenic effect of orally administered bisphenol A (BPA) was investigated in a rainbow trout (Oncorhynchus mykiss) test system. Bisphenol A was administered orally to sexually immature rainbow trout every second day for up to 12 d in doses between 1.8 and 258 mg/kg every second day (/2d). Plasma vitellogenin was measured before and during the exposures, and the concentrations of BPA in plasma, liver, and muscle and the plasma concentrations of BPA glucuronic acid (BPAGA) were determined at the end of the experiments. Increases in average plasma vitellogenin levels were seen at oral exposure to 24 mg BPA/kg/2d; the most sensitive fish responded to 9.3 mg/kg/2d. At day 12, the 10, 50, and 90% effective doses for increase in vitellogenin synthesis were 13, 19, and 25 mg/kg/2d, respectively. Bisphenol A could be detected in liver, muscle, and plasma at the end of the exposure, generally in increasing concentrations with increasing doses; liver concentrations generally were higher than muscle concentrations. Four to five hours after the last feeding of doses between 3.6 and 24 mg BPA/kg, plasma BPA concentrations ranged between 400 and 1,200 nM, whereas BPAGA concentrations were between 2- and 10-fold higher. The difference between BPA and BPAGA concentrations increased with increasing BPA dose. Bisphenol A showed little tendency to bioaccumulate in rainbow trout; less than 1% of the total amount of BPA administered orally at doses between 1.8 and 258 mg/kg/2d over the 10- or 12-d experimental period was retained in muscle and liver at 5 or 24 h after the end of the experiments.
Enantioselective acetylcholinesterase inhibition of the organophosphorous insecticides profenofos, fonofos, and crotoxyphos
Authors: Nillos Mae Grace , Rodriguez-Fuentes Gabriela , Gan Jay , Schlenk Daniel 
Published: August 2007

Abstract
A large number of organophosphorous insecticides (OPs) are chiral compounds, and yet enantioselectivity in their environmental fate and effects is rarely addressed. In the present study, we isolated individual enantiomers of three OPs, profenofos, fonofos, and crotoxyphos, and evaluated enantioselectivity in their inhibition of acetylcholinesterase (AChE). Acetylcholinesterase inhibition by the enantiomers and racemates was determined in vivo in the aquatic invertebrate Daphnia magna and in Japanese medaka (Oryzias latipes) as well as in vitro with electric eel (Electrophorus electricus) and human recombinant AChEs. The overall results showed variable sensitivity between AChE enzymes from different species as well as variable magnitude of enantioselectivity in enzyme inhibition. The (—)-enantiomer of profenofos was 4.3- to 8.5-fold more inhibitory to AChE in vivo, whereas (—)-fonofos was 2.3- to 29-fold more potent than the corresponding (+)-enantiomer. The (+)-enantiomer of crotoxyphos was 1.1- to 11-fold more inhibitory to AChE than the (—)-enantiomer. In contrast, the in vitro results showed (+)-profenofos to be 2.6- to 71.8-fold more inhibitory than the (—)-enantiomer and (—)-crotoxyphos to be 1.6- to 1.9-fold more active than the (+)-enantiomer. The reversed direction of enantioselectivity observed between the in vivo and in vitro assays suggests enantioselectivity within toxicodynamic processes such as uptake, biotransformation, or elimination. Findings from the present study provide evidence of enantioselectivity in the AChE inhibition of chiral OPs in nontarget organisms and indicate the need to consider enantiomers individually when assessing environmental risk of these chiral pesticides.
The sorptive capacity of animal protein
Authors: deBruyn Adrian M.H. , Gobas Frank A.P.C. 
Published: August 2007

AbstractPartition coefficients that are used to predict concentrations of hydrophobic organic chemicals in biota (e.g., the bioconcentration factor) often assume that the sorptive capacity of an organism or tissue is adequately represented by its lipid content. In lean organisms and tissues, however, theory suggests that partitioning may be strongly influenced by the sorptive capacity of nonlipid materials, such as protein. Little is known about the sorptive capacity of proteins for hydrophobic organic chemicals, and methods to include proteins in bioaccumulation models do not exist. Here, we present a compilation and meta-analysis of published data to estimate the relative sorptive capacities of animal proteins and lipids for neutral organic chemicals. We found that the estimated sorptive capacity of protein in solid animal tissues ranged from around 1 to 10% that of lipid for compounds with a log octanol/water partition coefficient (KOW) of greater than two. The sorptive capacity of blood protein (albumin) appeared to be substantially higher than this, especially for low-KOW chemicals. For modeling purposes, we recommend estimating the sorptive capacity of animal protein as 5% that of lipid. According to this estimate, the sorptive capacity of an animal or tissue will be dominated by the contribution from protein if the lipid content makes up less than 5% of the dry-weight organic content. In such situations, a consideration of the sorptive capacity of nonlipid constituents, such as protein, will permit more accurate predictions of chemical accumulation and distribution.
Availability of polychlorinated biphenyls in field-contaminated sediment
Authors: You Jing , Landrum Peter F. , Trimble Tricia A. , Lydy Michael J. 
Published: August 2007

AbstractTwo chemical approaches, Tenax extraction and matrix solid phase microextraction (matrix-SPME), were evaluated as surrogates to estimate bioavailability of polychlorinated biphenyls (PCBs) from field-contaminated sediment. Aroclor 1254 was the primary contaminant found in sediment from Crab Orchard Lake in Marion, Illinois, USA, and a total of 18 PCB congeners were selected for study. Bioaccumulation was determined by exposing the freshwater oligochaete, Lumbriculus variegatus, to the sediment for 28 d. Differences in the rapidly desorbing fraction of PCBs and fraction desorbed within 6 h, defined by Tenax extraction, accounted for 39 and 31% of the differences among biota-sediment accumulation factor values, respectively. A better relationship (r2 = 0.95) was found between the oligochaete PCB body residues and the concentration of PCBs in the rapidly desorbing fraction of sediment. The degree of chlorination and planarity of the PCB congeners affected both desorption and bioaccumulation. The higher chlorine substituted and planar PCBs showed less chemical and biological availability, due to their stronger sorption to sediment, compared to the lower chlorinated and nonplanar PCBs. Accumulation of PCBs by L. variegatus correlated well (r2 = 0.88) with matrix-SPME fiber concentrations. The ratio of measured body residue to estimated body residue from the pore water concentration measured by matrix-SPME ranged from 0.4 to 1.3 with an average of 0.9. Overall, both Tenax and matrix-SPME approaches were useful surrogates of bioaccumulation for a field-contaminated sediment.
Determinants of variability in acute to chronic toxicity ratios for aquatic invertebrates and fish
Authors: Raimondo Sandy , Montague Brian J. , Barron Mace G. 
Published: August 2007

Abstract
Variability in acute to chronic ratios (ACRs; median lethal or effect concentration divided by chronic value) has been of continuing interest in aquatic toxicology because of the reliance on ACRs to estimate chronic toxicity for chemicals and species with known acute toxicity data but with limited or no information for chronic toxicity. To investigate the variability and significant differences in ACRs, an extensive data set was compiled of 456 same-species pairs of acute and maximum acceptable toxicant concentrations for metals, narcotics, pesticides, and other organic chemicals. The overall median value for 456 aquatic invertebrate and fish ACRs analyzed in the present study was 8.3, with a 16,000-fold range in values (1.1–18,550) and a 32-fold range in 10th and 90th percentile values (2.5–79.5). Median ACRs for taxa, ambient habitat media, chronic test end point, and chemical mode of action (MOA)/class categories generally were similar but, in some cases, extremely variable (ranges of 1 to gt;10,000). No significant differences (p ⩽ 0.05) were found in median ACRs between taxa, although invertebrate ACRs generally were more variable than fish ACRs. Freshwater organisms had median ACRs significantly greater than those of saltwater species and also were more variable. No significant differences were found in median ACRs among chemical MOA/class data sets; however, ACR variance differed significantly among MOAs. Although few significant differences occurred among median ACRs for different groups, those categories that were highly variable are at an increased risk of underestimated chronic toxicity when mean or median ACRs are used.
Aspects of petrochemical pollution in southeastern Louisiana (USA): Pre-Katrina background and source characterization
Authors: Iqbal Javed , Gisclair David , McMillin Debra J. , Portier Ralph J. 
Published: August 2007

Abstract
Background petroleum pollution before Hurricane Katrina in southeastern Louisiana (USA) coastal sediments was evaluated at 320 locations in three consecutive years for polycyclic aromatic hydrocarbons (PAHs), saturated alkanes (nC9-nC35), and petroleum biomarker compounds (hopanes, steranes, pristane, and phytane). Approximately 90% of the sample locations had a total PAH concentration of less than 2.0 μg/g and total saturated alkane concentration of less than 17 μg/g, with 50% indicating a total PAH concentration of less than 200 ng/g. Upper limit or baseline high concentration for total PAHs was 1.5 μg/g, comparable to the 2.18 μg/g reported for the National Status and Trends (NST) Program of the National Oceanic and Atmospheric Administration (NOAA). Thus, 85% of sites were below the baseline high concentration. Baseline high total PAHs at 6% of the sites (described as land) was 5.1 μg/g, comparable to the 4 μg/g benchmark calculated for NST. The three-year average total PAH concentration for 95% of the sites was less than 7.5 μg/g, a defined limit of fivefold the baseline high concentration. Samples indicated petrogenic, pyrogenic, and natural/biogenic hydrocarbon inputs. Contaminant levels exceeded the state soil screening limits at only 3% of the 320 locations. Federal screening limits proposed by the NOAA for ecological effects were exceeded at only 18% of the sites (including those sites exceeding the state limit). Only 4% of the sites had concentrations exceeding the NOAA effect range-low (ER-L) in more than one collection year. At least 61% of the analytes exceeding the ER-L were pyrogenic source indicators. Source-fingerprint analysis of these selected samples showed 10 samples with notable petroleum contamination, whereas six indicated pyrogenic input. Of all samples collected, only one site showed relatively fresh/lightly weathered petroleum.
Participatory dam systems modelling: a case study of the transboundary Guadiana River in the Iberian Peninsula
Authors: Máñez M. , Froebrich J. , Ferrand N. , Silva A. 
Published: August 2007

Modelling tools have been widely used to investigate best management practices. But in contrast to the plethora of modelling studies, the practical implementation of outcomes is comparatively small. There is an urgent need to implement results and to show the practical validation of the concept developed, especially against the context of water stress mitigation.
The participative development of modelling studies as a joint effort of stakeholders and modellers is seen as a key to achieve a wider identification, acceptance, trust and applicability of results. Participatory planning in the water sector is also increasingly requested in water management, where tasks have been for clarified decades through different institutional arrangements and national laws. Stakeholder involvement in water resources management have been limited to what was long time seen as participation, merely information on action to be taken. In the last decade the need for participation has been reflected in different ways. In Europe, the implementation of the Water Framework Directive (WFD) under Art. 14, requires all the European countries to involve stakeholders in decision making processes on water resource management.
The aim of this paper is to present and discuss the research framework and possible results of investigating dam modelling through participatory systems modelling. We introduce a structured approach to use participatory modelling (PM) for stimulating the integration of modelling and decision making, also as a way of implementation of some articles of the WFD. The results and the framing of this paper are part of the AQUASTRESS Project.
The conceptual modelling has been developed by a multidisciplinary research team, local stakeholders and local experts. Some results are discussed and recommendations made.