bluuebunny/crossref_metadata_2025_split huggingface dataset:
Decreased toxicity of Al to Juvenile Atlantic salmon (Salmo salar) in acidic soft water containing natural organic matter: A test of the free-ion model
Authors: Roy Robert L , Campbell Peter G C 
Published: March 2010

AbstractToxicological experiments were designed to test the predictions of the free-ion model (FIM) in a soft, acidic water containing Al and a natural fulvic acid (FA). Juvenile Atlantic salmon (Salmo salar) were exposed to Al in either inorganic or organic acidic soft waters, at pH 5.0, and 50% lethal concentrations (LC50) values were determined for both exposure solutions. Contrary to the predictions of the FIM, the LC50s, expressed as inorganic Al (Ali), were significantly higher (p &lt; 0.05) in the organic solution (6.1–8.0 μM Ali) than in the inorganic medium (2.9–4.0 μM Ali). Preexposure of the fish to a 10-mg/L FA solution at pH 5.0, without Al, did not protect the animals from a subsequent Al challenge in solutions without FA. A regression model related mortality with Ali and total organic carbon (TOC) and was highly significant (proportion mortality [arcsine] = −0.215 + [0.81]log[Ali] — [0.44]TOC; p &lt; 0.0001, R2 = 0.71). We conclude that natural FA may play an independent protective role in solutions containing Al, in addition to that of decreasing Al toxicity by complexation of the metal and reducing the free Al3+ concentration.
Acute toxicity and structure-activity relationships of nine alcohol ethoxylate surfactants to fathead minnow and Daphnia magna
Authors: Wong Diana C L , Dorn Philip B , Chai Eric Y 
Published: March 2010

Abstract
Auatic toxicity of nine commercial-grade alcohol ethoxylate surfactants was studied in acute exposures to fathead minnow (Pimephalespromelas) and Daphnia magna. All studies were conducted in accordance with USEPA TSCA Good Laboratory Practice Standards. Mean measured surfactant concentrations in the exposure solutions showed good agreement with nominal concentrations for both fathead minnow (R2 = 0.98, p = 0.05) and daphnid (R2 = 0.99, p = 0.05) tests. Surfactant recoveries ranged from 59 to 97% and 67 to 106% in the fathead minnow and daphnid solutions, respectively. Response of both species to the surfactants was generally similar. Surfactant toxicity tended to increase with increasing alkyl chain lengths. The effect of low average ethylene oxide (EO) groups on increased surfactant toxicity was more evident in the daphnid exposures. Quantitative structure-activity relationship (QSAR) models were developed from the data, which relate surfactant structure to toxicity. The models predict increasing toxicity with decreasing EO number and increasing alkyl chain length. The models also indicate that average alkyl chain length has a greater effect on toxicity than average EO groups. Further, the models indicate that both species did not differ markedly in their response to alkyl chain length effects, while the number of EO groups had a stronger effect on daphnids than fathead minnow. Model-predicted toxicity agreed well with toxicity estimated from USEPA alkyl ethoxylates SARs and with toxicity values reported in the literature for several surfactants previously studied.
Risk assessment on the basis of simplified life-history scenarios
Authors: Calow Peter , Sibly Richard M , Forbes Valery 
Published: March 2010

Abstract
Ecological risk assessment ought to make predictions about the likely effects of chemical contaminants on populations and ecosystems. However, current procedures either make these links on the basis of oversimplified approaches that obscure the relationship between what is measured in ecotoxicological tests and what we are trying to protect or are too demanding in terms of both data and understanding to be used practically and routinely. Here we develop an approach that uses simplified life-history models to make explicit and ecologically relevant links between test results and their implications for population dynamics and explore the possibility of extending this to an appreciation of ecosystem effects. These models also make a number of simplifying assumptions but in being explicit they are open to challenge and elaboration, and we argue that, in general, the assumptions are usually precautionary. The development of these models in itself gives some nonintuitive insights into the theory of ecotoxicological responses, and we illustrate the practical application of the theory using a number of hypothetical case studies.
Statistical models to predict the toxicity of major ions to Ceriodaphnia dubia, Daphnia magna and Pimephales promelas (fathead minnows)
Authors: Mount David R , Gulley David D , Hockett J Russell , Garrison Tyler D , Evans James M 
Published: March 2010

Abstract
Toxicity of fresh waters with high total dissolved solids has been shown to be dependent on the specific ionic composition of the water. To provide a predictive tool to assess toxicity attributable to major ions, we tested the toxicity of over 2,900 ion solutions using the daphnids, Ceriodaphnia dubia and Daphnia magna, and fathead minnows (Pimephales promelas). Multiple logistic regression was used to relate ion composition to survival for each of the three test species. In general, relative ion toxicity was K+ &gt; HCO3− ≈ Mg2+ &gt; Cl− &gt; SO42−; Na+ and Ca2+ were not significant variables in the regressions, suggesting that the toxicity of Na+ and Ca2+ salts was primarily attributable to the corresponding anion. For C. dubia and D. magna, toxicity of Cl−, SO42−, and K+ was reduced in solutions enriched with more than one cation. Final regression models showed a good quality of fit to the data (R2 = 0.767–0.861). Preliminary applications of these models to field-collected samples indicated a high degree of accuracy for the C. dubia model, while the D. magna and fathead minnow models tended to overpredict ion toxicity.
Sampling of air streams and incorporation of samples in the Microtox™ toxicity testing system
Authors: Kleinheinz Gregory T , St. John Wayne P 
Published: March 2010

Abstract
A sudy was conducted to develop a rapid and reliable method for the collection and incorporation of biofiltration air samples containing volatile organic compounds (VOCs) into the Microtox™ toxicity testing system. To date, no method exists for this type of assay. A constant stream of VOCs was generated by air stripping compounds from a complex mixture of petroleum hydrocarbons (PHCs). Samples were collected on coconut charcoal ORBO (Supelco, Inc.) tubes and the VOCs extracted with methylene chloride. The compounds extracted were then solvent exchanged into dimethyl sulfoxide (DMSO) under gaseous nitrogen. The resulting DMSO extract was directly incorporated into the Microtox toxicity testing system. In order to determine the efficiency of the solvent exchange, the VOCs in the DMSO extract were then extracted into hexane and subsequently analyzed using gas chromatography (GC) with a flame ionization detector (FID). It was determined that all but the most volatile VOCs could be effectively transferred from the ORBO tubes to DMSO for Microtox testing. Potential trace amounts of residual methylene chloride in the DMSO extracts showed no adverse effects in the Microtox system when compared to control samples.
Effects of water hardness on the toxicity of manganese to developing brown trout (Salmo trutta)
Authors: Stubblefield William A , Brinkman Steven F , Davies Patrick H , Garrison Tyler D , Hockett James R , McIntyre Matthew W 
Published: March 2010

Abstract
Manganese is a common constituent of point and nonpoint discharges from mining and smelting activities. Available data indicate that Mn is acutely toxic at relatively high aqueous concentrations, when compared with trace metals, and its toxicity is affected by water hardness. Little information is available regarding the chronic toxicity of manganese. Early-life-stage (ELS) tests were conducted to determine the toxicity of manganese to brown trout (Salmo trutta) and to evaluate the extent to which water hardness (ranging from 30 to 450 mg/L as CaCO3) affects the chronic toxicity of Mn. Water hardness significantly affected Mn chronic toxicity, with toxicity decreasing with increasing hardness. Decreased survival was the predominant effect noted in the 30-mg/L hardness experiment, while significant effects on growth (as measured by changes in body weight) were observed in both the 150- and 450-mg/L hardness experiments. Twenty-five percent inhibition concentration (IC25) values, based on the combined endpoints (i.e., survival and body weight), were 4.67, 5.59, and 8.68 mg Mn/L (based on measured Mn concentrations) at hardness levels of approximately 30, 150, and 450 mg/L as CaCO3, respectively.
The use of cholinesterase and carboxylesterase activities fromMytilus galloprovincialisin pollution monitoring
Authors: Escartín Estefania , Porte Cinta 
Published: March 2010

AbstractAcetylcholinesterase (AChE), butyrylcholinesterase (BChE), and carboxylesterase (CbE) activities have been measured in gills and digestive gland of the mussel Mytilus galloprovincialis. AChE activity was predominantly localized in gills, whereas the highest BChE and CbE specific activities were detected in digestive glands. Commonly used pesticides were examined in vitro for their ability to inhibit mussel esterases; the results obtained pointed out the highest sensitivity of mussel CbE to low concentrations of pesticides, but also the higher sensitivity of gill cholinesterases over digestive gland forms. Seasonal variation in the activity of gill esterases was determined monthly in mussels collected from the Ebro Delta, an area where pesticides and biocides are frequently used. As a general trend, elevated cholinesterase activities were detected in winter, possibly indicating little or no exposure to organophosphorous compounds, whereas the lowest cholinesterase activities were reported over the summer period. These changes were related to agricultural activities in the area and are supported by the detection of organophosphorous pesticides in the tissue of M. galloprovincialis.
Comparative developmental dermal toxicity and mutagenicity of carbazole and benzo[a]carbazole
Authors: Dutson Sheryl M , Booth Gary M , Schaalje G Bruce , Castle Raymond N , Seegmiller Robert E 
Published: March 2010

AbstractThe objectives of this study were (1) to determine the developmental toxicity of carbazole and benzo[a]carbazole following daily dermal administration to female Sprague-Dawley rats on days 0 through 20 of gestation and (2) to determine the mutagenicity of these two compounds using a modified version of the Ames assay. These chemicals are of concern because they are found in a variety of environmental matrices including crude oil mixtures. No signs of maternal or developmental toxicity were considered to be related to dermal administration of carbazole at doses of 2.5, 25.0, and 250.0 mg/kg. Signs of maternal toxicity considered to be related to administration of benzo[a]carbazole included significantly decreased body-weight gain and decreased absolute-food consumption at a dose of 250.0 mg/kg. Signs of developmental toxicity considered to be related to administration of benzo[a]carbazole included significantly decreased number of total (live and dead combined) and live pups on lactation day 0 as well as significantly decreased average pup weight on lactation days 0 and 4 at a dose of 250.0 mg/kg. Because developmental toxicity following benzo[a]carbazole treatment was observed only at a dose at which maternal toxicity was observed, it is likely that the effects on the offspring are secondary to the treatment effects on the dam. Evidence of toxic effects with benzo[a]carbazole in the absence of effects with carbazole suggests that the substituted benzene ring enhances the biological activity of this compound. Carbazole was nonmutagenic with or without S-9 activation, whereas benzo[a]carbazole showed a clear dose–response with S-9 activation. Without S-9 activation, benzo[a]carbazole was nonmutagenic. Apparently benzo[a]carbazole must be enzymatically activated in order to be mutagenic.
Assessing sediment quality in heterogeneous environments: A case study of a small urban harbor in Lake Champlain, Vermont, USA
Authors: Watzin Mary C , McIntosh Alan W , Brown Erik A , Lacey Rebekah , Lester Deborah C , Newbrough Kathleen L , Williams Ann R 
Published: March 2010

AbstractRelatively few case studies have been conducted demonstrating the utility of multiple endpoint approaches to sediment quality assessment in areas with moderate contaminant levels and heterogeneous conditions. Because variability is commonplace in natural systems, assessment approaches must be designed explicitly for these conditions. In an assessment of highly heterogeneous freshwater sediments in Lake Champlain, Vermont, USA, we measured multiple endpoints, including physical and chemical characteristics of the sediment, acute and chronic toxicity in three tests (Ceriodaphnia dubia, Chironomus tentans, and Pimephales promelas), and benthic community composition, at 19 sites throughout Inner Burlington Harbor. Multiple regression techniques were used to investigate whether significant relationships existed between biological endpoints and the physical and chemical characteristics of the sediments. Although all three laboratory exposures indicated toxicity at some sites, little correspondence was found among the tests. No changes in the benthic community could be attributed to trace contaminants. Multiple regression was useful in showing associations between contaminants, grain size, toxicity, and benthic community composition. Although not demonstrating causal linkages, these statistical analyses suggested which factors might be important in driving measured responses. In heterogeneous sites, an individualized assessment approach based on a preliminary analysis of variability might provide the most useful information.
Phototoxicity of individual polycyclic aromatic hydrocarbons and petroleum to marine invertebrate larvae and juveniles
Authors: Pelletier Marguerite C , Burgess Robert M , Ho Kay T , Kuhn Anne , McKinney Richard A , Ryba Stephan A 
Published: March 2010

AbstractPhototoxicity resulting from photoactivated polycyclic aromatic hydrocarbons (PAHs) has been reported in the literature for a variety of freshwater organisms. The magnitude of increase in PAH toxicity often exceeds a factor of 100. In the marine environment phototoxicity to marine organisms has not been reported for individual or complex mixtures of PAHs. In this study, larvae and juveniles of the bivalve, Mulinia lateralis, and juveniles of the mysid shrimp, Mysidopsis bahia, were exposed to individual known phototoxic PAHs (anthracene, fluoranthene, pyrene), as well as the water-accommodated fractions of several petroleum products (Fuel Oil #2, Arabian Light Crude, Prudhoe Bay Crude, Fuel Oil #6) containing PAHs. Phototoxicity of individual PAHs was 12 to &gt;50,000 times that of conventional toxicity. Three of the petroleum products demonstrated phototoxicity while the lightest product, Fuel Oil #2, was not phototoxic at the concentrations tested. The phototoxicity of petroleum products appears to be dependent on the composition and concentrations of phototoxic PAHs present: lighter oils have fewer multiple aromatic ring, phototoxic compounds while heavier oils have higher levels of these types of molecules. This study shows that phototoxicity can occur in marine waters to marine species. Further, the occurrence of oil in marine waters presents the additional risk of phototoxicity not routinely assessed for during oil spills.
Ion-exclusion chromatographic determination of carboxylic acids used to support the microbially mediated reductive dechlorination of tetrachloroethene
Authors: Xu Ning , Vandegrift Steve , Fine Dennis D , Sewell Guy W 
Published: March 2010

Abstract
An analytical method was developed for the determination of lactic acid, formic acid, acetic acid, propionic acid, and butyric acid in environmental microcosm samples using ion-exclusion chromatography. The chromatographic behavior of various eluents was studied to determine the optimum analytical conditions for eluent concentration and flow rate. Matrix effects caused by inorganic anions including carbonate were investigated. Methods for carbonate removal were also examined. Sub mg/L detection limits and small analytical variations (less than 1%) were obtained with all five acids. Calibration curves with regression coefficients (r2) of 0.998 to 1.000 were obtained for acid concentrations ranging from 2.00 to 200.00 mg/L. The total run time for five carboxylic acids was less than 20 min with a relatively small sample volume requirement (∼0.5 ml). The recoveries of the acids from microcosm samples were between 80 to 102%.
Use of ceriofast™ for monitoring the toxicity of industrial effluents: Comparison with the 48-H acute Ceriodaphnia toxicity test and Microtox®
Authors: Jung Keumhee , Bitton Gabriel 
Published: March 2010

Abstract
A comparison of an acute1-h Ceriodaphnia dubia toxicity test (CerioFAST™) with Microtox® and the standard acute 48-h C. dubia acute toxicity test was undertaken to determine the toxicity of a variety of industrial effluents. CerioFAST is based on suppression of feeding activity of C. dubia in the presence of toxicants and consists of a 1-h-exposure period to a given toxicant followed by a 20-min-feeding period using fluorescent yeast cells. Twenty-eight industrial effluent samples, collected from northern and central Florida, were tested and compared using the CerioFAST and the standard 48-h C. dubia acute toxicity test. The results of the CerioFAST assay were well correlated with the standard 48-h C. dubia test (r2 = 0.98). Therefore, CerioFAST is useful as a rapid-screening test or range-finding test for assessing the toxicity of environmental samples.
Different susceptibilities to white phosphorus poisoning among five species of ducks
Authors: Steele Benjamin B , Reitsma Leonard R , Racine Charles H , Burson Sherman L , Stuart Robin , Theberge Rebecca 
Published: March 2010

Abstract
Three species of ducks, mallard (Anas platyrhynchos), northern pintail (Anas acuta), and green-winged teal (Anas crecca), that frequent an estuarine salt marsh in Alaska during migration die in large numbers from ingesting particles of white phosphorus. Two other common species, northern shoveler (Anas clypeata) and American wigeon (Anas americana), are rarely found dead. Selectivity indices show that this difference in mortality is not due to different numbers of each species being present. We investigated three hypotheses for the difference in susceptibility to this poison. First, we found that wigeons had more total grit in their gizzards than the susceptible species and shovelers had a high proportion of particles &gt;1 mm compared to other species. Thus, ingestion of particles of white phosphorus as grit cannot explain the differences in susceptibility. Second, feeding behavior could not completely account for the lack of susceptibility in shovelers. Shovelers often forage with their neck or more in the water and often have their bills in the sediments. Wigeon, however, frequently forage with just their bill in the water and rarely penetrate the sediments. This feeding behavior, coupled with a diet consisting mainly of plants, may limit exposure of wigeon. Third, shovelers have wide upper bills, with lamellae consisting of long thin filaments extending from the upper bill inward toward the lower bill. These lamellae may allow white phosphorus particles to be flushed out during feeding. Thus, if physiological tolerance to white phosphorus is similar among these species, the difference in susceptibility appears to be due to differences in feeding behavior and bill morphology.
Ecological risk assessment of a wetland exposed to boron
Authors: Powell Rebecca L , Kimerle Richard A , Coyle Gerald T , Best G Ronnie 
Published: March 2010

Abstract
A wetland located in the southeastern portion of the United States was the site of an investigation to determine the potential ecological risk of elevated boron concentrations to the flora and fauna living in the wetland. The conceptual model identified the vegetation as the primary receptor of concern, and thus the vegetation is the focus of this article. Samples of surface water, sediments, and selected vegetation were collected from the study wetland and several nearby reference sites and were analyzed for boron. Concentrations of boron in all three media exceeded reference site concentrations. Boron concentrations were highest near the suspected source but decreased almost to reference-site concentrations near the outer perimeter of the wetland. Some plants appeared stressed with yellowing and necrotic leaves; however, a correlation between tissue boron concentrations and the plant's visual appearance was not apparent for all species studied. Modeling of the fate of boron indicated that the wetland has likely been at a steady state for many years and that boron concentrations were not expected to increase. It was concluded that no observable adverse ecological impacts to the vegetation could be attributed to boron, nor is it likely that the boron poses an unacceptable risk to the surrounding areas.
Predicting plant uptake of organic chemicals from soil or air using octanol/water and octanol/air partition ratios and a molecular connectivity index
Authors: Dowdy Deanna L , McKone Thomas E 
Published: March 2010

Abstract
A bioconcentration ratio (BCR) represents the ratio of the concentration of a chemical found in an exposed biological system, such as a plant or fish, to the concentration in the exposure medium (water, soil, or air). A comparison is made of the precision and accuracy of the molecular connectivity index (MCI) and the octanol/water partition coefficient (Kow) as predictors of BCRs from the soil matrix into above- or below-ground vegetation tissues. Calculated octanol/air partition coefficient (Koa) values are compared with calculated Kow and MCI values as predictors of measured air-to-plant BCRs. Based on a statistical evaluation of explained variance, residual error, and cross-validation, this evaluation reveals that the MCI provides higher precision, greater ease of use, and a more cost-effective method for predicting the potential bioconcentration of a chemical from soil into above-ground vegetation. Statistical analyses of the various methods reveal that both the Kow and MCI approaches have a similar level of precision for predicting BCRs from soil solution into roots and, among MCI, Koa and Kow; Koa is somewhat more precise and valid than MCI and Kow for estimating uptake, but all have limited accuracy as bioconcentration predictors. These latter results are derived mainly from the paucity of both reliable Koa values and measured air-to-plant BCRs and indicate a need for more experimental measurements from which more accurate models may be developed.
Effects of pH, chloride and Calcium(II) on adsorption of monomethylmercury by soils
Authors: Yin Yujun , Allen Herbert E , Huang C.-P , Sanders Paul F 
Published: March 2010

Abstract
Adsorption of monomethylmercury (MMHg) by soil from 2 × 10−7 and 1 × 10−6 M solutions was investigated to understand soil-water partitioning of MMHg. The effects of three factors—pH, Cl−, and Ca2+—on adsorption were examined. Adsorption as a function of pH followed a concave downward profile with the maximum adsorption occurring at pH between 5 and 6. Less adsorption at low pH values mainly resulted from the proton competition for surface sites and Cl− complexation for MMHg. Decreases in adsorption at high pH values are attributed to the complexation of MMHg with soluble organic ligands whose concentrations increase with pH. Addition of 1.0 × 10−3 M CL decreased adsorption at low pH where CH3HgCl was dominant over CH3HgOH, and exhibited no effect on adsorption at high pH when CH3HgOH became predominant. The presence of a low concentration of Ca2+ (1.0 × 10−4 M) had no effect on MMHg adsorption; however, a high concentration of Ca2+ (3.3 × 10−3 M) increased adsorption at pH &lt; 6 but had no effect at pH &gt; 6. This is ascribed to the combined effects of pH and Ca2+ on the solubility of organic ligands.