bluuebunny/crossref_metadata_2025_split huggingface dataset:
Using Biowin™, Bayes, and batteries to predict ready biodegradability
Authors: Boethling Robert S. , Lynch David G. , Jaworska Joanna S. , Tunkel Jay L. , Thom Gary C. , Webb Simon 
Published: November 2004

Abstract
Wether or not a given chemical substance is readily biodegradable is an important piece of information in risk screening for both new and existing chemicals. Despite the relatively low cost of Organization for Economic Cooperation and Development tests, data are often unavailable and biodegradability must be estimated. In this paper, we focus on the predictive value of selected Biowin™ models and model batteries using Bayesian analysis. Posterior probabilities, calculated based on performance with the model training sets using Bayes' theorem, were closely matched by actual performance with an expanded set of 374 premanufacture notice (PMN) substances. Further analysis suggested that a simple battery consisting of Biowin3 (survey ultimate biodegradation model) and Biowin5 (Ministry of International Trade and Industry [MITI] linear model) would have enhanced predictive power in comparison to individual models. Application of the battery to PMN substances showed that performance matched expectation. This approach significantly reduced both false positives for ready biodegradability and the overall misclassification rate. Similar results were obtained for a set of 63 pharmaceuticals using a battery consisting of Biowin3 and Biowin6 (MITI nonlinear model). Biodegradation data for PMNs tested in multiple ready tests or both inherent and ready biodegradation tests yielded additional insights that may be useful in risk screening.
Estimation of microbial reductive transformation rates for chlorinated benzenes and phenols using a quantitative structure–activity relationship approach
Authors: Tebes-Stevens Caroline L. , Jones W. Jack 
Published: November 2004

Abstract
A set of literature data was used to derive several quantitative structure–activity relationships (QSARs) to predict the rate constants for the microbial reductive dehalogenation of chlorinated aromatics. Dechlorination rate constants for 25 chloroaromatics were corrected for the effects of hydrophobic partitioning and adjusted for the observed distribution of product species. A number of physicochemical properties and molecular parameters were considered for inclusion in the QSARs. Multivariate statistical analyses were used to select the optimal set of descriptors to minimize multicollinearity between the descriptors, as well as to minimize the p-value of the regression coefficients. The final QSAR included four descriptors: The logarithm of the octanol–water partition coefficient (Kow), the summation of the Hammett sigma constants, and the sigma induction constants in the ortho and meta positions relative to the transformation reaction center. The predictive ability of this QSAR was evaluated using 24 site-specific rate constants that were measured in five separate studies and were not used to derive the expression. The peer-reviewed literature was screened carefully to ensure that all rate constant data were representative of environmentally relevant conditions.
Distribution of atrazine into three chemical fractions: Impact of sediment depth and organic carbon content
Authors: Smalling Kelly L. , Aelion C. Marjorie 
Published: November 2004

Abstract
The fate and transport of organic contaminants in aquatic sediments are impacted largely by microbial degradation and sorption to organic matter. Atrazine, a pre-emergent herbicide, has the potential to contaminate groundwater because of its slight water solubility, long half-life, and sorption to organic matter. Mineralization and distribution of 14C-atrazine into three chemical fractions were monitored over time in surface and subsurface coastal aquatic sediments of different land use. Sediments were extracted with an organic solvent followed by an alkali hydrolysis, and 14C activity was measured in the aqueous, solvent, and basic fractions (representing nonsorbed compounds, loosely sorbed compounds, and humic or fulvic acid bound compounds, respectively). Limited mineralization of atrazine occurred (&lt;4%). The 14C activity in the aqueous and basic fractions increased over time, was greater in surface versus subsurface sediments, and was positively correlated with sediment organic carbon (SOC) content, indicating greater biological and chemical activity. Total 14C recovered ranged from 50 to 90%, was less in surface versus subsurface sediments, and was not correlated with SOC after 80 d. These results suggest that in native aquatic surface sediments, atrazine sorption plays a major role, whereas in subsurface sediments atrazine may be available for degradation and transport to shallow groundwater.
Effects of dietary zinc exposure on the life history of the parthenogenetic springtail Folsomia candida (Collembola: Isotomidae)
Authors: Smit C. Els , Stam Ed M. , Baas Nicolette , Hollander Ronald , van Gestel Cornelis A. M. 
Published: November 2004

Abstract
The effect of zinc on growth and reproduction of the springtail Folsomia candida has been determined for individual animals exposed to contaminated food. Zinc caused a decrease in growth of the springtails, which resulted in a decrease in the estimated final fresh weight at the highest exposure level (20 mg/g dry food). Other effects were observed from 5 mg/g dry food and included an increase of the juvenile period, an increase of development time, a reduction in first-clutch size and egg viability, and a reduction in the number of individuals reaching the reproductive state. The effect of these changes on the population growth rate was evaluated using an estimated value for mortality in the field. In the present analysis, the juvenile period was the most sensitive variable.
Kinetics of toluene sorption and desorption in Ca- and Cu-montmorillonites investigated with Fourier transform infrared spectroscopy under two different levels of humidity
Authors: Shih Yang-Hsin , Wu Shian-Chee 
Published: November 2004

Abstract
Clays in soils or groundwater aquifer materials play roles in the sorption of organic pollutants. The intrinsic sorption kinetics of toluene in dry and humid clay films was investigated by tracking the change of infrared absorbance. Under the humid condition, similar toluene-sorbed intensities were found in Ca- and Cu-montmorillonites. However, a higher intensity of sorbed toluene was found in the Cu-form than in the Ca-form under the dry condition, which indicates a stronger interaction occurring in dry Cu-montmorillonite. The general time scale of sorption of toluene on clays is around 100 s. In both forms of montmorillonite, some portion of toluene was desorbed at an extremely slow rate under the dry condition. Some newly identified peaks were persistent against desorption from montmorillonites, suggesting the existence of irreversibly sorbed species and the possibility of toluene transformation occurring in clay systems.
Linking metal bioaccumulation of aquatic insects to their distribution patterns in a mining-impacted river
Authors: Cain Daniel J. , Luoma Samuel N. , Wallace William G. 
Published: November 2004

Abstract
Although the differential responses of stream taxa to metal exposure have been exploited for bioassessment and monitoring, the mechanisms affecting these responses are not well understood. In this study, the subcellular partitioning of metals in operationally defined metal-sensitive and detoxified fractions were analyzed in five insect taxa. Samples were collected in two separate years along an extensive metal contamination gradient in the Clark Fork River (MT, USA) to determine if interspecific differences in the metal concentrations of metal-sensitive fractions and detoxified fractions were linked to the differences in distributions of taxa relative to the gradient. Most of the Cd, Cu, and Zn body burdens were internalized and potentially biologically active in all taxa, although all taxa appeared to detoxify metals (e.g., metal bound to cytosolic metal-binding proteins). Metal concentrations associated with metal-sensitive fractions were highest in the mayflies Epeorus albertae and Serratella tibialis, which were rare or absent from the most contaminated sites but occurred at less contaminated sites. Relatively low concentrations of Cu were common to the tolerant taxa Hydropsyche spp. and Baetis spp., which were widely distributed and dominant in the most contaminated sections of the river. This suggested that distributions of taxa along the contamination gradient were more closely related to the bioaccumulation of Cu than of other metals. Metal bioaccumulation did not appear to explain the spatial distribution of the caddisfly Arctopsyche grandis, considered to be a bioindicator of metal effects in the river. Thus, in this system the presence/absence of most of these taxa from sites where metal exposure was elevated could be differentiated on the basis of differences in metal bioaccumulation.
A bayesian approach to parameter estimation for a crayfish (Procambarus spp): Bioaccumulation model
Authors: Lin Hsin-I , Berzins David W. , Myers Leann , George William J. , Abdelghani Assaf , Watanabe Karen H. 
Published: November 2004

Abstract
Bioaccumulation models are used to describe chemical uptake and clearances by organisms. Averaged input parameter values are traditionally used and yield point estimates of model outputs. Hence, the uncertainty and variability of model predictions are ignored. Probabilistic modeling approaches, such as Monte Carlo simulation and the Bayesian method, have been recommended by the U.S. Environmental Protection Agency to provide a quantitative description of the degree of uncertainty and/or variability in risk estimates in ecological hazards and human health effects. In this study, a Bayesian analysis was conducted to account for the combined uncertainty and variability of model parameters in a crayfish bioaccumulation model. After a 5-d exposure in the LaBranche Wetlands (LA, USA), crayfish were analyzed for polycyclic aromatic hydrocarbon concentrations and lipid fractions. The posterior distribution of model parameters were derived from the joint posterior parameter distributions using a Markov chain Monte Carlo approach and the experimental data. The results were then used to predict the distribution of chrysene concentration versus time in the crayfish to compare the predicted ranges at the different study sites.
Quantitative structure-activity relationship modeling of acute toxicity of quaternary alkylammonium sulfobetaines to Daphnia magna
Authors: Davies Joanna , Ward Robert S. , Hodges Geoffrey , Roberts David W. 
Published: November 2004

Abstract
The logarithm of the octanol/water partition coefficient has been widely used as the sole physicochemical property to define various types of biological activity, such as aquatic toxicity. In the present study, we derive a quantitative structure–activity relationship (QSAR) equation for the prediction of acute aquatic toxicity (48-h median effective concentration) of quaternary alkylammonium sulfobetaines to the aquatic invertebrate Daphnia magna Straus. The single-parameter approach described is also based on the hydrophobicity parameter, log P. The 17 zwitterionic compounds were considered for QSAR development. They have the general formula RN+(CH3)2(CH2)nSO3−, where n = 2 to 4, and were synthesized by reacting the corresponding N,N-dimethylamines with either sodium-2-chloroethanesulfonate (n = 2), 1,3-propanesultone (n = 3), or 1,4-butanesultone (n = 4). The R group was either a C6 to C12 alkyl chain, a phenylalkyl unit bearing a C1 to C4 chain, or a phenylpropyl unit with a C4 to C6 para-substituted alkyl group. Octanol/water partition coefficients were experimentally determined via a conventional stir-flask procedure, which was quantified using a reverse-phase, high-performance liquid chromatographic technique coupled with either an ultraviolet or an electrospray ionization mass spectrometry detection system. Median effective concentration values were also determined experimentally via a standard acute immobilization test recommended by Organisation for Economic Cooperation and Development (Paris, France) Guideline 202. The established QSAR equation for such zwitterionic compounds is consistent with the standard equation that normally defines the polar narcosis mode of toxic action.
A field test and comparison of acute and chronic sediment toxicity tests with the estuarine amphipod Leptocheirus plumulosus in Chesapeake Bay, USA
Authors: McGee Beth L. , Fisher Daniel J. , Wright David A. , Yonkos Lance T. , Ziegler Gregory P. , Turley Steven D. , Farrar J. Daniel , Moore David W. , Bridges Todd S. 
Published: November 2004

Abstract
A 28-d partial life-cycle test with the estuarine amphipod Leptocheirus plumulosus was developed in response to the need for an assay to mimic chronic exposure to sediment-associated contaminants. To ensure that toxicity tests have environmental relevance, it is essential to evaluate the relationship between laboratory responses and field measures of contamination. Consequently, one objective of the study was to compare the results of the chronic sediment toxicity test with L. plumulosus to gradients of sediment contamination and the in situ benthic community in its native Chesapeake Bay. Chronic tests were conducted by two laboratories, the Army Corps of Engineers Waterways Experiment Station ([WES]; Vicksburg, MS, USA) and the University of Maryland ([UM] College Park, MD, USA) using different feeding regimes, providing the opportunity to evaluate the effect of this variable on response sensitivity. A second objective was to compare the relative sensitivity of acute and chronic tests with L. plumulosus with field-collected sediments. Overall, there was good agreement between the toxicological response of acute and chronic tests with L. plumulosus and field measures of contamination. Survival in the acute test and chronic test conducted by WES was negatively correlated with concentrations of sediment-associated contaminants. Survival in acute exposures was significantly reduced in sediments from 8 of 11 stations. Indigenous L. plumulosus were found only at two of the three stations that did not exhibit acute toxicity. An unexpected finding was the difference in responsiveness of the two chronic tests. Survival in tests conducted by UM and WES was significantly reduced in sediments from 4 and 6 of 11 stations, respectively. No additional sublethal toxicity was detected in the UM chronic test, but the WES test detected reproductive effects at two additional stations. We believe the observed differences were related to the test diet used. Partly as a result of our findings, the recommended diet for the L. plumulosus chronic test was changed in the final methods document.
Effects of the pesticides captan, deltamethrin, isoproturon, and pirimicarb on the microbial community of a freshwater sediment
Authors: Widenfalk Anneli , Svensson Jonas M. , Goedkoop Willem 
Published: November 2004

Abstract
In three microcosm experiments, we exposed microbial communities of a natural sediment to environmentally relevant concentrations of the fungicide captan, the herbicide isoproturon, and the insecticides deltamethrin and pirimicarb. Exposure concentrations were estimated negligible concentrations (NCs), maximum permissible concentrations (MPCs), and 100 times MPC (100MPC). Experimental endpoints were microbial community respiration and biomass, bacterial activity, and denitrification. All four pesticides inhibited bacterial activity by 20 to 24% at MPC, which corresponded to concentrations in the range of μg/kg dry-weight sediment. Treatments with deltamethrin and isoproturon showed inhibiting effects on bacterial activity at NC exposures. Surprisingly, for captan, deltamethrin, and isoproturon, this inhibiting effect was not observed at 100MPC treatments. Microbial biomass was negatively effected in MPC treatments with deltamethrin and in NC treatments with isoproturon. The tested pesticides did not affect community respiration and denitrification rates. These results show that exposure to the tested pesticides may induce toxic responses in sediment microbial communities at concentrations that are predicted to be environmentally safe.
Influence of soot on hydrophobic organic contaminant desorption and assimilation efficiency
Authors: Lamoureux Elizabeth M. , Brownawell Bruce J. 
Published: November 2004

Abstract
Soot, soot-amended sediment, and unamended sediment spiked with hydrophobic organic contaminants (HOC) were subjected to laboratory desorption and assimilation efficiency experiments in an effort to assess and compare the importance of soot in controlling HOC desorption and deposit-feeder assimilation efficiency. Three contaminants, naphthalene (NAP), benzo[a]pyrene (BaP), and hexachlorobenzene (HCB) were sorbed to sediments, sediments amended with soot (2–4% dry wt), and soot for a period of 34 d. Desorption of all three contaminants into seawater from the three prepared sorbates was then monitored, and Nereis succinea assimilation efficiency experiments on the BaP- and HCB-contaminated sorbates were conducted. Both NAP and BaP desorption rates for soot and soot-amended sediments were reduced by at least a factor of two relative to unamended sediment. Hexachlorobenzene desorption rates were similar for both the soot-amended and the unamended sediments. Results of N. succinea assimilation efficiency experiments indicate a trend similar to the desorption experiments: higher assimilation of BaP from unamended relative to soot-amended sediment and little difference in assimilation between treatments for HCB. However, soot was more effective in reducing BaP desorption than assimilation efficiency, which would be consistent with the hypothesis that the gut fluid dissolution by deposit feeders may partially decouple biological availability from chemical availability.
Role of source matrix in the bioavailability of polycyclic aromatic hydrocarbons to deposit-feeding benthic invertebrates
Authors: Rust Aaron J. , Burgess Robert M. , McElroy Anne E. , Cantwell Mark G. , Brownawell Bruce J. 
Published: November 2004

Abstract
The bioavailability of polycyclic aromatic hydrocarbons (PAHs) to benthic organisms is complicated by the variety of ways that they are introduced to coastal waters (dissolved, as nonaqueous phase liquids, and tightly bound to soot, coal, tire rubber, and eroded shale). In order to better understand the controlling variables that affect chemical and biological availability of PAHs, a study was conducted in which three deposit-feeding infaunal benthic invertebrate species (Cirriformia grandis, Clymenella torquata, and Macoma balthica) were exposed to sediments amended with PAH-rich materials (coal dust, tire rubber, diesel soot, creosote, crude oil, and fuel oil). Lipid and organic carbon normalized bioaccumulation factors (BAFlocs) were calculated after 20 d of exposure and PAH bioavailability from the different treatments was assessed. Bioaccumulation of coal-derived PAHs usually was too low to be measured, though PAHs associated with soot and tire rubber showed significant accumulation in organism tissues. Polycyclic aromatic hydrocarbons from the fuel oil, creosote, and crude oil treatments were more bioavailable than PAHs bound in solid carbonaceous matrices (soot, coal, and tire rubber). Desorption of PAHs from the amended sediments into seawater also was measured using XAD resin. As was observed with bioaccumulation, PAHs in coal were desorbed the least; tire rubber and diesel soot were intermediate; and creosote, fuel oil, and crude oil desorbed to the greatest extent. In only one out of the three species evaluated was PAH bioaccumulation related to extent of desorption after 20 d. Decoupling between biological and chemical availability may be due to species-specific factors such as surfactant-mediated solubilization in the guts of some deposit-feeding organisms. A significant finding of this work was the demonstration that PAHs associated with soot and tire rubber in their native state (rather than experimentally added) are available to some benthic biota.
Influence of soot carbon on the bioaccumulation of sediment-bound polycyclic aromatic hydrocarbons by marine benthic invertebrates: An interspecies comparison
Authors: Rust Aaron J. , Burgess Robert M. , McElroy Anne E. , Cantwell Mark G. , Brownawell Bruce J. 
Published: November 2004

Abstract
The sorption of polycyclic aromatic hydrocarbons (PAHs) to soot carbon in marine sediments has been hypothesized to reduce PAH bioavailability. This hypothesis was tested for eight species of marine benthic invertebrates (four polychaete worms, Clymenella torquata, Nereis virens, Cirriformia grandis, and Pectinaria gouldii, and four bivalve mollusks, Macoma balthica, Mulinia lateralis, Yoldia limatula, and Mya arenaria) that span a wide range of feeding behavior, ability to metabolize PAHs, and gut chemistry. Organisms were exposed for 20 d to two PAH-spiked sediments, one with soot and one without soot. The soot treatment generally resulted in lower bioaccumulation than the no soot treatment, though the differences between treatments were not significant for all species. All but one species accumulated significant PAH concentrations in their tissues from the soot treatment, indicating that soot-bound PAH cannot be dismissed as unavailable to infaunal benthic biota. Bioaccumulation factors were correlated negatively to both the organisms' ability to metabolize PAHs and the gut fluid contact angle, supporting the hypotheses that high PAH metabolism results in lower bioaccumulation factors and bioavailability of PAHs may be limited partially by PAH solubilization in the gut lumen. The variability in bioaccumulation due to the soot treatment was much less than the variability between species and between PAH analytes. Comparatively low bioaccumulation was observed in Nereis virens, a species commonly used in bioaccumulation tests. These results suggest that more effort is needed in understanding the salient characteristics of species present in a threatened environment, rather than focusing solely on the sediment geochemistry (e.g., soot and organic carbon content) and contaminant characteristics when predicting ecological risk of PAH-contaminated sediments.