bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sorption and toxicity of azo and triphenylmethane dyes to aquatic microbial populations
Authors: Michaels Glenda B. , Lewis David L. 
Published: March 2010

Abstract
Toxicity and sorption of five azo and triphenylmethane dyes to freshwater microbiota were determined to assess, in part, the risks that these dyes may pose to the aquatic environment. The toxicities of Basic Violet 1, Basic Violet 2, Basic Violet 3, Basic Green 4 and Tropaeolin 0 were established by determining the percent survival of microbiota when dyes were incorporated into plating media. Basic Violet 3 was the most toxic, with a mean survival rate of 20.7 ± 6.57% at a dye concentration of 5.0 mg/L. Tropaeolin 0 was the least toxic, with a survival rate of 92.0 ± 9.57%. Survival increased with decreasing dye concentration. Sorption of the dyes to viable cells required from 8 to 24 h to reach equilibrium. Partition coefficients were higher for viable cells than for heat-killed cells, suggesting that a metabolic process may be involved in sorption of these dyes or that autoclaving the cells reduces the organisms' cation exchange capacities.
Environmental exposure assessment: Experience under the toxic substances control act
Authors: Daniels S. L. , Hoerger F. D. , Moolenaar R. J. 
Published: March 2010

Abstract
The Toxic Substances Control Act (TSCA) has focused governmental attention on the process of assessing the hazards from commercial chemicals. Environmental behavior and impact must be projected before the chemical is released. This requires a knowledge of the environment, relevancy of laboratory data, extent of necessary data and interpretation of those data for future impacts. The responsibility for the data rests with the manufacturer. The key criterion involves a determination of “unreasonable risk.” Six axiomatic principles of risk assessment are identified. This involves an interactive and interdisciplinary thought process that is both iterative and staged. A generalized procedure for exposure assessment has been developed. An initial risk assessment comparing projected environmental concentrations with probable effect levels determines the type and quantity of laboratory test data needed. As examples, three new and three existing chemicals with widely differing properties and uses have been evaluated for their potential environmental impacts.
Inter- and intralaboratory variability in Daphnia magna effluent toxicity test results
Authors: Grothe Donald R. , Kimerle Richard A. 
Published: March 2010

Abstract
A nine-laboratory round-robin study of the Daphnia magna static, acute, effluent toxicity test was conducted to examine inter- and intralaboratory variability in test results. A single effluent sample was split and sent to three government, three commercial and three industrial aquatic laboratories. Each laboratory followed a specifically designed test protocol and reported the number of daphnids immobilized in each of seven effluent test concentrations at 24 h and 48 h of exposure. The mean 48-h EC50 value for all data was 5.3% effluent. The range was 3.5 to 9.1% effluent, so there is a factor of 2.6 between the highest and lowest EC50 values. The pooled within-laboratory standard deviation and coefficient of variation were 0.91 and 16%, respectively. Combined inter-and intralaboratory estimates of standard deviation and coefficient of variation were 1.8 and 33%, respectively. The results of this study show that Daphnia magna effluent toxicity data can be reproduced both within and between laboratories when clearly defined test protocols are employed.
A transport model for water-soluble constituents of synthetic oil spills in rivers
Authors: Herbes Stephen E. , Yeh Gour-Tsyh 
Published: March 2010

Abstract
A numerical model was developed to predict dissolved aqueous concentrations of phenolic contaminants resulting from accidental spillage of a synthetic oil into a river. The model (termed SOPTRAN, for synthetic oil pollutant transport) simultaneously solves algorithms for processes of oil slick spreading, oil evaporation, phenolics dissolution, advection and dispersion using an implicit integrated compartment method. To test SOPTRAN, predictions were compared with measurements of phenolics dissolution into underlying water following application of a coal-liquefaction product to two 3.75 × 3.75 × 1 m ponds. The mean of measured concentrations during phenolics dissolution was 84% (coefficient of variation = 43%) of predicted values. With minimal calibration, SOPTRAN adequately described differential rates of dissolution of phenol and C1- to C4-alkylphenol isomer groups. The model was used to simulate a hypothetical 300-m3 (80,000-gal) accidental release of a coal liquid from a barge into a large navigable river under both instantaneous and noninstantaneous (i.e., leakage) spill scenarios.
Comparison of fish toxicity screening data for 55 alcohols with the quantitative structure-activity relationship predictions of minimum toxicity for nonreactive nonelectrolyte organic compounds
Authors: Lipnick Robert L. , Johnson David E. , Gilford James H. , Bickings Charlene K. , Newsome Larry D. 
Published: March 2010

Abstract
A comparison was made between the fish toxicity screening test results at concentrations of 5 to 10 mg/L and the LC50 values predicted by the narcotic quantitative structure-activity relationship (QSAR) equation of Könemann for 55 alcohols containing no additional heteroatom functional groups. The majority of the QSAR-predicted toxicities are consistent with the test data. The results for two chemicals predicted to be toxic but showing no effects were explained by a water solubility cutoff. Five chemicals exhibited toxicity at concentrations 20 to more than 10,000 times below those predicted. Four of these contained a double or triple bond attached to a carbon atom bearing a primary or secondary alcohol moiety. Their toxicity was explained by a proposed pro-electrophile mechanism in which an electrophilic toxicant is produced metabolically by the enzyme alcohol dehydrogenase.
Fish subchronic toxicity prediction model for industrial organic chemicals that produce narcosis
Authors: Call D. J. , Brooke L. T. , Knuth M. L. , Poirier S. H. , Hoglund M. D. 
Published: March 2010

Abstract
A model based on partition coefficient was developed for predicting subchronic toxicities of selected chemicals to fish. Early life stage tests were conducted under flow-through conditions using fathead minnows (Pimephales promelas) as test organisms. Embryos, larvae and juveniles were continuously exposed to chemicals for a total of 31 to 33 d. Test endpoints included egg hatchability, incidence of developmental abnormalities, survival and growth. The “chronic value” for each test was a point estimate of the maximum acceptable toxicant concentration (MATC), and was determined as the geometric mean of the highest test concentration producing no effect and the lowest concentration significantly (p ≤ 0.05) affecting one or more endpoints. Ten industrial organic compounds from four chemical classes (ketones, benzenes, ethers and alkyl halides) were used in model development. All chemicals were considered to induce narcosis in fish in acute toxicity tests. The relationship between estimated MATC n-octanol/water partition coefficient (log P) was expressed by the equation
log estimated MATC (mol L−1) = -0.886 log P - 2.18 (r2 = 0.925).
This model was used to predict subchronic toxicities for eight other alkyl halides and chlorinated benzenes that had been tested with fathead minnows and reported in the literature. The mean ratio for observed chronic toxicity value to predicted chronic toxicity value was 2.00 ± 2.03. Observed values ranged from 0.29 to 6.02 times the predicted values. For the 10 chemicals used in the model, the mean acute/chronic toxicity ratio (96-h LC50/chronic value) was 12.2 ± 8.5.
Structure-activity relationships for organotin compounds
Authors: Laughlin Roy B. , French W. , Guard H. , Johannesen R. B. , Brinckman F. E. 
Published: March 2010

Abstract
The LC50 concentrations of a series of 15 structurally distinct diorganotins (R2SnX2) and triorganotins (R3SnX) were determined for zoeae of the mud crab Rhithropanopeus harrisii. Zoeae were exposed from hatching until metamorphosis, at ˜14 d. The LC50 values varied by almost 4 orders of magnitude, from the least toxic aquated species, dimethyltin (LC50 = 92,276 nM) to the most toxic, tricyclohexyltin (LC50 = 19.8 nM). Within a homologous series, the diorganotin was less toxic than the corresponding triorganotin, but the toxicity of the two classes overlapped, e.g., dicyclohexyltin was more toxic than trimethyltin and about as toxic as triethyltin. Correlations between the Hansch π parameter and the LC50, and between total surface area and the LC50, suggest that aqueous thermodynamic activity (hydrophobicity), a function of the organic ligand attached to tin, controls bioconcentration and thus the lethal dose. This conclusion is substantiated by the observation of a single linear relationship between a sum of Hansch fragment constants and the LC50 values for both the di- and triorganotins. The difference in toxicity between di- and trialkyltins results from a decrease in hydrophobic character when a hydroxyl group is substituted for an organic ligand in the former. Any electronic effect of the organic ligand is overwhelmed by the factors that control hydrophobic behavior, as evidenced by the observed poor correlations with χ.
Predicting the bioavailability of organic xenobiotics to Pontoporeia hoyi in the presence of humic and fulvic materials and natural dissolved organic matter
Authors: Landrum Peter F. , Reinhold Mark D. , Nihart Sheila R. , Eadie Brian J. 
Published: March 2010

Abstract
Dissolved organic carbon (DOC) in water sorbs or binds organic xenobiotics, reducing the amount of compound that is “freely dissolved” and therefore the amount bioavailable to Pontoporeia hoyi. The apparent biological uptake rate constant for each compound is proportional to the inverse of the Aldrich humic acid concentration as a source of DOC. The log of the DOC concentration required to reduce the apparent uptake rate constant by 50% correlates well with the log of the partition coefficient to DOC determined by reverse-phase methodology for partition coefficients as low as 104. Further, the partitioning to DOC determined by reverse-phase methodology and from the toxicokinetics in P. hoyi yields partition coefficients similar to those of Aldrich humics measured as DOC and DOC from Lake Michigan interstitial waters. The partition coefficients determined by the two methods correlate well and only vary by a constant bias of a factor of approximately 3. Thus the partition coefficient determined by reverse-phase methodology can be used to predict the bioavailable concentration of organic compounds in water containing DOC for P. hoyi.
Fate and effects of 3,4-dichloroaniline in the laboratory and in outdoor ponds: I. fate
Authors: Wolff C. J. M. , Crossland N. O. 
Published: March 2010

Abstract
Process analysis and a mathematical model were used to evaluate and predict the fate of 3,4-dichloroaniline (DCA) in 40-m3 outdoor ponds. Six ponds were treated with DCA: three with a nominal concentration of 450 μg/L and three with a nominal concentration of 45 μg/L. These concentrations were maintained in the water by repeated applications during a period of 28 d. The predicted fate of DCA was compared with its observed fate.
The dominant loss process was predicted to be direct phototransformation. Using the mathematical model SOLAR and an empirical correction for cloud cover, the rate constant for this process was calculated to be 0.12 to 0.20 d−1. Observed absorbance data for pond water were used to estimate the rate of indirect phototransformation to be 0.01 to 0.02 d−1. Evaporation, hydrolysis and biodegradation were predicted to be of minor importance. The partition coefficient of DCA between wet sediment and water was predicted to be near unity for the range of observed pH values. From this it was calculated that only 3% of the compound would be sorbed and that, therefore, this process could be neglected.
The observed rate of loss of dissolved DCA from the ponds was 0.11 to 0.17 d−1, in good agreement with the predicted overall rate of loss, i.e., 0.13 to 0.22 d−1. It is concluded that the mathematical model SOLAR provided a reliable tool for predicting the rate of direct phototransformation of organic compounds in natural waters.
Fate and effects of 3,4-dichloroaniline in the laboratory and in outdoor ponds: II. chronic toxicity toDaphniaSPP. and other invertebrates
Authors: Crossland N. O. , Hillaby J. M. 
Published: March 2010

AbstractThe effects of 3,4,-dichloroaniline (DCA) on survival, growth and reproduction of the planktonic crustacean Daphnia magna were evaluated in the laboratory using a procedure based on Organization for Economic Cooperation and Development guidelines. Effects on reproduction, the most sensitive of the measured biological responses, occurred at a concentration of 20 μg/L but not at 10 μg/L or at lower concentrations. These, and similar results reported elsewhere, were used to calculate the maximum acceptable toxicant concentration (MATC) for D. magna.In acute toxicity tests with D. magna and D. longispina the 48-h EC50 values were 290 and 440 μg/L, respectively. An estimate of the MATC for D. longispina was then obtained by multiplication of the MATC for D. magna by the ratio of the 48-h EC50 values for the two species.A field experiment was carried out to compare the chronic toxicity of DCA in the laboratory with effects on populations of zooplankton and communities of macroinvertebrates in outdoor ponds. Three ponds were treated with DCA at a nominal concentration of 45 μg/L and three at 450 μg/L. These concentrations were maintained in the water for 28 d. Three untreated ponds were used as controls. Population densities of the dominant species of zooplankton were monitored before, during and after treatment with DCA. Samples of the macroinvertebrate communities were taken immediately after the end of treatment. Birth, death and growth rates of D. longispina populations were monitored using Perspex cylinders to confine samples of adults in situ for periods of 24 h.Population densities of D. longispina were significantly affected (p ≤ 0.05) by both treatment levels. There were no adverse effects on the population densities of two species of copepods and no changes were observed in the structure of macroinvertebrate communities. It was concluded that the Cladocera were much more susceptible to DCA than were other groups of invertebrates in the outdoor ponds.Birth and growth rates of D. longispina populations were highly sensitive to the effects of DCA. They were depressed when concentrations of DCA were maintained at a level greater than the MATC and increased rapidly when concentrations decreased below this level. Thus, the MATC, derived from the results of toxicity tests, provided an accurate estimate of threshold concentrations affecting field populations of D. longispina.
Reduction in bioavailability to bluegills of polycyclic aromatic hydrocarbons bound to dissolved humic material
Authors: McCarthy John F. , Jimenez Braulio D. 
Published: March 2010

Abstract
The uptake, depuration, metabolic fate and bioaccumulation of two polycyclic aromatic hydrocarbons (PAH), [14C]naphthalene (NPH) and [14C]benzo(α)pyrene (BaP), by bluegill sunfish were determined in the presence and absence of dissolved humic material (DHM) (20 mg C/L) The effect of binding to DHM on the bioavailability of PAH was analyzed by multicompartment kinetic models to determine the relative rates of uptake of PAH dissolved in water versus that bound to DHM. DHM reduced the accumulation of BaP by 90% (97% of BaP bound to DHM) but had little effect on uptake of NPH (2% bound to DHM). The rate coefficients for uptake of bound PAH were only 0 to 10% of the uptake of dissolved PAH. The potential for biotransformation has an important role in bioaccumulation by fish. Although accumulation of total radioactivity (PAH and metabolites) is 10-fold greater in fish exposed to BaP than in fish exposed to NPH, BaP is extensively metabolized whereas NPH is not. Consequently, the bioconcentration of the parent NPH greatly exceeds that of the parent BaP. Because more hydrophobic PAH, such as BaP, have a high affinity for binding to DHM and rapid rates of biotransformation, these interactions may act to mitigate the biological impact of those very hydrophobic PAH having the greatest potential for bioaccumulation and transfer to humans via food chains.
Adaptation of estuarine ecosystems to the biodegradation of nitrilotriacetic acid: Effects of preexposure
Authors: Pfaender Frederic K. , Shimp Robert J. , Larson Robert J. 
Published: March 2010

Abstract
The biodegradation of nitrilotriacetic acid (NTA) was examined in three estuarine ecosystems, one of which had been exposed previously to the chemical. Biodegradation was measured as the conversion of radiolabeled NTA to 14CO2, 14C-labeled cells and the amount of label remaining in solution. The relatively unpolluted Newport River estuary system in North Carolina metabolized NTA slowly, with no apparent increase in rate over time. Jamaica Bay in New York showed an adaptation response, with approximately 50 d required for the onset of relatively rapid rates of biodegradation. The Fraser River estuary in Canada, exposed to NTA for more than 10 years, showed rapid degradation with no lag period at a concentration of 10 μg/L. At 100 and 2,000 μg/L, short lag periods (2 to 4 d) were observed before rapid degradation rates were achieved. Measurements of NTA-degraders indicated that the Fraser River estuary contained 650/ml versus fewer than 10 in the Newport River and Jamaica Bay communities. The results demonstrate that NTA can be degraded by estuarine microorganisms. Estuarine bacteria will adapt to the presence of NTA in the environment and, after adaptation, can respond to increased levels of the compound after relatively short lag periods.
Microbial metabolism of chlorophenolic compounds in ground water aquifers
Authors: Suflita Joseph M. , Miller Gary D. 
Published: March 2010

Abstract
The metabolism of phenol and various chlorophenols was studied in groundwater aquifer microcosms. Flow-through column microcosms containing pristine aquifer material were used to assess aerobic biodegradation processes. Reductive metabolism of the substrates was studied in serum bottles filled with aquifer material contaminated by municipal landfill leachate. We found that microorganisms present in an actively methanogenic aquifer were able to metabolize chlorophenols by replacing the halogen substituents with hydrogen atoms. The identity of the dehalogenated intermediates was confirmed by mass spectrometry for a model substrate and by cochromatography for others. Complete removal of the aryl halides was necessary before the phenol intermediate could be mineralized to methane and carbon dioxide. However, the chlorophenols tended to persist in anoxic microcosms containing material from the same aquifer but from a non-methanogenic site. Metabolism and acclimation of chlorophenols and phenol was noted in aerobic microcosm studies, but the degradation pathway(s) were not established.
Short-term fish and amphibian embryo-larval tests for determining the effects of toxicant stress on early life stages and estimating chronic values for single compounds and complex effluents: Complex mixtures
Authors: Birge Wesley J. , Black Jeffrey A. , Westerman Albert G. 
Published: March 2010

Abstract
A short-term embryo-larval test is described for use with single compounds or complex effluents. Exposure was initiated soon after fertilization and maintained for 4 d after hatching, which gave an exposure period of 6 to 8 d for a number of fish and amphibian species. Test responses included mortality and teratogenesis. Probit analysis was used to calculate median lethal (LC50) and threshold (LCI) concentrations. Standard statistical tests also were performed to determine no observed effect concentrations. Multiple tests were performed with cadmium as the reference toxicant, using continuous-flow and static-renewal procedures; results substantiated high precision and good repeatability. Cadmium LCI values agreed closely with cadmium chronic values determined in life-cycle studies. The review of published data also supported close correlations between LCIs and chronic values for metals. The procedure also worked satisfactorily for a multiple-species test in which eggs of three species were maintained in mixed populations using the same exposure chambers. The test also was conducted in the laboratory to screen seven major industrial effluents. The test for effluent biomonitoring was further evaluated in two major field studies. As compared with 96-h flow-through acute tests with the fathead minnow, the short-term embryo-larval test was decidedly more sensitive and reliable for characterizing the toxicity of complex effluents.
Investigation of the hepatic mixed-function oxidase system in herring gull embryos in relation to environmental contaminants
Authors: Boersma Dora C. , Ellenton Jennifer A. , Yagminas Algis 
Published: March 2010

Abstract
We measured hepatic enzyme activity in 25-d embryos from eight colonies in the Great Lakes and one relatively uncontaminated colony in the Bay of Fundy. This was done to further investigate the use of the mixed-function oxidase system of herring gull (Larus argentatus) embryos for bioeffects monitoring. The changes in ethoxyresorufin o-dealkylation (ERoD) and the rate of aminopyrene-N-demethylation (APDM) across the Great Lakes were small. However, the rate of aniline hydroxylation (AnH) was significantly depressed in seven of eight colonies when compared with control colony. This suppression was greatest in embryos from the three colonies in Lake Ontario, where mirex levels were highest. Organochlorines were measured in egg homogenates from each colony. There was a significant negative correlation of the rate of APDM with both polychlorinated biphenyl and hexachlorobenzene levels and also of the rate of AnH with mirex levels. In conjunction with the above, an egg injection experiment using three doses each of hexachlorobenzene and mirex was conducted to elucidate these compounds' effects on the enzymes measured. The effects on body weight, liver weight and enzyme activity were small compared with the mortality incurred in the eggs injected with hexachlorobenzene. The embryonic LD50 for hexachlorobenzene was calculated as 4.3 ppm. Mortality in the controls injected with 1,4-dioxane was 20%, and that of eggs injected with mirex was similar to that of controls.