bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bioaccumulation kinetics of brominated flame retardants (polybrominated diphenyl ethers) in blue mussels (Mytilus edulis)
Authors: Gustafsson Kerstin , Björk Mikael , Burreau Sven , Gilek Michael 
Published: March 2010

Abstract
Baltic Sea blue mussels, Mytilus edulis, were exposed to polybrominated diphenyl ethers (PBDEs, IUPAC congeners 47, 99, and 153) and polychlorinated biphenyls (PCBs, congeners 31, 52, 77, 118, and 153) in a flow-through experimental setup for 44 d. After the exposure phase, the mussels were allowed to depurate in natural brackish water for 26 d. After analyses, uptake clearance rate coefficients (ku), depuration rate coefficients (kd), and bioaccumulation factors (BAF) were calculated. A rapid uptake of all PBDEs and PCBs was observed, especially for PBDE congeners 47 and 99 (ku 120 and 170 L/day/g dry weight, respectively). The depuration rate decreased with increasing hydrophobicity as expected for the PCBs, but for the PBDEs, depuration rate coefficients appeared to be of the same magnitude for all three congeners independently of log Kow. The BAFs obtained for PBDE 47 and PBDE 99 (1.3 × 106 and 1.4 × 106 ml/g dry weight, respectively) were higher than for all other substances in the study, severalfold higher than for PCBs of similar hydrophobicity. The presented data indicate that the bioaccumulation potential of PBDEs, extensively used as flame retardants, is similar or higher than that of PCBs for filter feeding organisms such as blue mussels.
Role of chemical and ecological factors in trophic transfer of organic chemicals in aquatic food webs
Authors: Russell Ronald W , Gobas Frank A P C , Haffner G Douglas 
Published: March 2010

Abstract
Trophic transfer of chlorinated organic contaminants was investigated in an aquatic community composed of zooplankton, benthic invertebrates, and fish. Biomagnification, measured as the increase in lipid-based chemical concentrations in predator over that in prey, was observed for high-Kow chemicals (logKow &gt; 6.3). Low-Kow chemicals (log Kow &lt; 5.5) did not biomagnify in the food web, and chemicals with log Kow between 5.5 and 6.3 showed some evidence of biomagnification. Trophic level differences in chemical accumulation in the food web could not be attributed to bioconcentration into increasing trophic levels with increasing lipid levels, as no relationship was observed between trophic position and lipid content of organisms. Plots of contaminant-ordinated principal component scores in component space predicted the detailed diets of the species examined. It is concluded that (1) trophic interactions play a crucial role in the distribution of high-Kow chemicals but not for low-Kow chemicals and that (2) contaminant distributions provide a means to determine structure in aquatic communities.
Elevated trace element concentrations and standard metabolic rate in banded water snakes (Nerodia fasciata) exposed to coal combustion wastes
Authors: Hopkins William A. , Rowe Christopher L , Congdon Justin D 
Published: March 2010

Abstract
Trace element concentrations in banded water snakes, Nerodia fasciata, and representative prey items from a site polluted by coal combustion wastes were compared with concentrations in conspecifics from a nearby reference site. Water snakes accumulated high concentrations of trace elements, especially arsenic (As) and selenium (Se), in the polluted habitat. In addition to being exposed to contaminants in water and sediments, snakes in the polluted site are exposed to contaminants by ingesting prey items that have elevated whole-body concentrations of trace elements, including As, cadmium (Cd), and Se. Snakes from the polluted site exhibited mean standard metabolic rates (SMR) 32% higher than snakes from the reference site. As a result, snakes from the polluted site appear to have elevated allocation of energy to maintenance and theoretically should have less energy available for growth, reproduction, and storage. Our findings are consistent with physiological responses recently documented in other organisms from the polluted site. We hypothesize that long-term exposure to coal ash–derived trace elements and the resultant accumulation of some elements are responsible for observed increases in SMR.
Effects of the organochlorine insecticide lindane (γ-C6H6Cl6) on the population responses of the freshwater amphipod Hyalella azteca
Authors: Blockwell Stephen J , Maund Stephen J , Pascoe David 
Published: March 2010

Abstract
Adult populations of Hyalella azteca, with similar reproductive potential, were exposed in the laboratory to a range of lindane concentrations below the 240-h adult LC50 (26.9 μg/L) for a period of 35 d. The reproductive status of each population was assessed through quantification of the precopulatory guarding behavior of Hyalella, the number of gravid females, and their brood sizes. At the end of the experiment, recruitment within the H. azteca populations was assessed, and the body lengths of individuals were measured using image analysis. By employing a range of integrated and quantifiable response criteria, the influence of lindane at the individual and at the population level was determined. A lowest observed effect concentration of 13.5 μg lindane/L was identified. The experimental results are discussed in relation to the reproductive strategies adopted within the treatment groups and with respect to previous toxicity data.
Use of fish gill cells in culture to evaluate the cytotoxicity and photocytotoxicity of intact and photomodified creosote
Authors: Schirmer Kristin , Herbrick Jo-Anne S , Greenberg Bruce M , Dixon D George , Bols Niels C 
Published: March 2010

AbstractThe influence of ultraviolet (UV) irradiation on creosote toxicity was investigated with the rainbow trout (Oncorhynchus mykiss) gill cell line, RTgill-W1, and two indicator dyes, alamar Blue™ and 5-carboxyfluorescein diacetate acetoxymethyl ester. These monitor redox potential and membrane integrity, respectively. After solubilization and chemical analysis, creosote was presented to cells in the dark to measure cytotoxicity or concurrently with UV irradiation to evaluate photocytotoxicity. Additionally, creosote was photomodified by 2 h of UV irradiation before presentation to cells in the dark or together with UV. Cytotoxicity was detected only at high nominal creosote concentrations, but photocytoxicity occurred at creosote concentrations 35-fold lower. All the aromatic hydrocarbons in creosote appeared to contribute to cytotoxicity, but photocytotoxicity was due only to the fluoranthene, pyrene, anthracene, and benzo[a]anthracene in the mixture. Photomodified creosote was much more cytotoxic than intact creosote and this difference was most pronounced in the alamar Blue assay. Likely, this was due to photomodification products that impaired the mitochondrial electron transport chain. Photomodified creosote was slightly less photocytotoxic than intact creosote. Overall these results indicate that UV irradiation potentially enhances the toxicity of creosote to fish in several different but significant ways.
Effects of chronic metal exposure and sediment organic matter on digestive absorption efficiency of cadmium by the deposit-feeding polychaete Capitella species I
Authors: Selck Henriette , Decho Alan W , Forbes Valery E 
Published: March 2010

Abstract
Organic matter such as humic acid and bacterial slime exopolymer are common in estuarine and coastal sediments, where they are ingested by animals that process particulate detritus. Both humic acid (HA; refractory) and exopolymer (EPS; easily digestible) bind metals and therefore might represent a source of particulate-bound metals to deposit-feeding organisms. This study examined how cadmium preexposure (3 and 30 μg Cd/g dry wt. sed.), gut passage time (GPT), and quality and quantity of the organic coating on sediment particles interact to determine cadmium absorption efficiency (Cd-AE) in Capitella sp. I. Pulse-chase experiments using 109Cd and 51Cr were used to determine Cd-AE in individual worms. Worms were given a pulse of carbon-cleaned, HA-coated or EPS-coated sediment particles. The third treatment was divided into three EPS concentrations (high, medium, and low). A 5-d preexposure to cadmium did not affect the egestion rates during either the preexposure period or the chase phase. Worms given a pulse of carbon-cleaned particles exhibited higher egestion rates during the chase phase than worms given a pulse of organic-coated particles, and no differences were seen in egestion rate between worms exposed to HA- and high-EPS-coated particles. Egestion rates decreased with increasing EPS concentration. The presence of refractory organic material decreased the absorption efficiency of cadmium from sediment relative to Cd-AE from carbon-cleaned sediment but not relative to Cd-AE from sediment coated with a high concentration of EPS. The Cd-AE increased linearly with increasing exopolymer coating on sediment particles. Overall, Cd-AE increased with increasing gut passage time in worms that were not preexposed, although Cd-AE from HA-coated particles was independent of gut passage time. Preexposure to cadmium reversed the relationship between gut passage time and cadmium absorption efficiency. Thus, the implications are that sedimentary organic matter and worm physiology might be especially important in controlling metal bioavailability in deposit-feeding organisms and should be considered in sediment quality approaches.
An investigation of the application of the Canadian water quality guidelines
Authors: Walker Sherry L , Gobas Frank A P C 
Published: March 2010

AbstractThe Canadian water quality guidelines for the protection of aquatic life assume that (1) the external water concentration is an effective measure of the concentration at the active site in organisms, which is ultimately responsible for a toxic response, and that (2) the safety factor accounts for any differences between laboratory and field conditions as well as the extrapolation from the effect concentration to a long-term no-effect concentration. This study examines these assumptions and assesses potential errors that environmental managers can make when applying the guidelines. The methodology is based on assessing the probability that internal concentrations of several contaminants are greater than or less than the “safe” concentration, assumed by the guideline, when the water concentration is at the water quality guideline. Results derived from empirical observations and a food-web bioaccumulation model show that a high probability (62–100%) exists that safe internal concentrations are exceeded for polychlorinated biphenyls, 1,2,4,5-tetrachlorobenzene, and hexachlorobenzene in Lake Ontario when the aqueous concentrations are at the water quality guideline values. This is due to field bioaccumulation factors being greater than the bioaccumulation factors in laboratory toxicity tests used for the water quality guideline development. Factors contributing to the exceedence of safe internal concentrations at the water quality guideline values are identified. Recommendations for improvement of the water quality guideline process are provided.
Understanding single-species and model ecosystem sensitivity: Data-based comparison
Authors: Versteeg Donald J , Belanger Scott E , Carr Gregory J 
Published: March 2010

AbstractRisk assessments for compounds released to the environment typically rely on single-species toxicity studies to predict concentrations at which effects may be observed. These single-species toxicity studies are usually conducted with a few species, cultured under optimum conditions (diet, temperature, light, etc.) and tested in clean water with constant exposure to the compound of interest. Chronic toxicity data are then extrapolated to the ecosystem during risk assessments to predict concentrations that will not adversely impact the environment. Several approaches have been developed that apply statistical methods to estimate toxicant concentrations adversely affecting a small percentage of single species (e.g., 5%). There are several rarely stated, and infrequently tested, biological and statistical assumptions required to make this extrapolation. One test of the ability to use single-species toxicity data to protect ecosystems is to compare effects on single species with effects on experimental and natural ecosystems (e.g., microcosms, model ecosystems, field). Towards this end, we summarized the chronic single-species and experimental ecosystem data on a variety of substances (n = 11), including heavy metals, pesticides, surfactants, and general organic and inorganic compounds. Single-species data were summarized as genus-specific geometric means using the NOEC or EC20 concentration. Genus mean values spanned a range of values with genera being affected at concentrations above and below those causing effects on model ecosystems. Geometric mean model ecosystem no effect concentrations corresponded to concentrations expected to exceed the NOEC of 10 to 52% of genera. This analysis suggests that laboratory-generated single-species chronic studies can be used to establish concentrations protective of model ecosystem, and likely whole ecosystem, effects. Further, the use of the 5% of genera affected level is conservative relative to mean model ecosystem data but is a fairly good predictor of the lower 95% confidence interval on the mean model ecosystem NOEC.
Photochemical oxidation of terbufos
Authors: Lee Cindy M , Anderson Barbara , Elzerman Alan W 
Published: March 2010

Abstract
We studied the photochemical oxidation of an organophosphorus pesticide, terbufos, in surface waters because its oxidation products are of concern. Terbufos sulfoxide and terbufos sulfone have toxicities for aquatic organisms similar to those of the parent compound. We measured a photolysis rate constant under natural sunlight conditions in distilled water of 0.68±0.17/h near Clemson, South Carolina, USA. Actinometer studies resulted in a mean reaction quantum yield for terbufos of 5.8 × 10−3. The measured half-life of 64 min is considerably faster than any of the other chemical or biochemical oxidation half-lives in soil or hydrolysis half-lives reported in the literature. Photolysis should be considered in evaluating the risk of terbufos to surface waters and aquatic organisms.
Global chemical fate of α-hexachlorocyclohexane. 1. Evaluation of a global distribution model
Authors: Wania Frank , Mackay Donald , Li Yi-Fan , Bidleman Terry F , Strand Asbjørn 
Published: March 2010

Abstract
Vertical atmospheric layering is included in a previously described, zonally averaged global multimedia distribution model. This model is used to simulate the fate of α-hexachlorocyclohexane (α-HCH), the main ingredient of the technical HCH pesticide mixture, for the 50 years of its large-scale use (1947−1997). Worldwide historic emission estimates are compiled, assigned to 10 climate zones, and used as input in model calculations. The performance of the model is evaluated by comparing calculated and measured concentrations in the atmosphere and seawater. A major focus is on the arctic and northern temperate environment, and emphasis is also placed on absolute levels, time trends, latitudinal profiles, and air-water exchange. In general, simulated and observed concentrations agree within one order of magnitude. Deviations are explained by the zonal averaging characteristics of the model and uncertainties associated with the environmental degradation rates of α-HCH. In both model results and observations, the dramatic decrease in the global emission of α-HCH is reflected in rapidly decreasing concentrations in the atmosphere and seawater, except in the Arctic Ocean, which apparently is the last refuge for α-HCH in the global environment. The model thus provides an illustration of the response characteristics of the global system to the reduced emissions of α-HCH. Its application to other chemicals with reduced emission is discussed.
Global chemical fate of α-hexachlorocyclohexane. 2. Use of a global distribution model for mass balancing, source apportionment, and trend prediction
Authors: Wania Frank , Mackay Donald 
Published: March 2010

Abstract
A global distribution model that was previously shown to give satisfactory results is used to study in more detail and quantitatively the fate of α-hexachlorocyclohexane (α-HCH) in the global environment. The results provide a comprehensive historical picture of the global behavior of this chemical, which after being used in huge amounts in the early 1980s, has since been essentially eliminated. The major pathway of α-HCH from a global perspective is the transfer from the site of application to the world oceans via rivers and the atmosphere. Major reservoirs were initially the soils in regions of application and are now the world oceans. Global distribution patterns can be explained by differential persistence in various climates and meridional transport in the atmosphere and oceans. Most of the α-HCH emitted globally has been degraded in the zones of application, and only very small fractions, probably less than 1%, have survived until the mid−1990s and have reached the Arctic. However, a large fraction of the α-HCH that has survived is now present in high latitudes. The Arctic Ocean as the final reservoir for α-HCH is likely to be slowly depleted, with a half-life of approximately one decade.
Effect of Tween surfactants on methanogenesis and microbial reductive dechlorination of hexachlorobenzene
Authors: Yeh Daniel H , Pennell Kurt D , Pavlostathis Spyros G 
Published: March 2010

AbstractThe effect of nine Tween surfactants (polyoxyethylene sorbitan fatty acid esters) on methanogenesis and the microbial reductive dechlorination of hexachlorobenzene (HCB) was examined using three anaerobic, HCB-dechlorinating mixed cultures, one glucose fed and two lactate fed, that were derived from contaminated estuarine sediments. The two lactate-fed cultures differed significantly in their metabolic activity, especially with respect to the rate and extent of HCB reductive dechlorination. The objective of the study was to screen and select biologically compatible surfactants for use in subsequent research on surfactant-enhanced bioavailability of sorbed-phase chlorinated organic contaminants. Addition of the Tween surfactants resulted in lower rates of methanogenesis and HCB dechlorination compared with the control (i.e., surfactant-free culture) for both the glucose-fed culture and the lactate-fed culture, which exhibited a high metabolic activity. Tween−61 and −65 exhibited the lowest inhibition of HCB dechlorination at initial surfactant concentrations of 200 and 1,000 mg/L. On the other hand, the Tween surfactants, especially Tween−81 and −85, enhanced the rates of both methanogenesis and HCB dechlorination when the low metabolic activity lactatefed culture was used. The observed rate enhancements may be attributed to bacterial cell membrane modification by the surfactants. Attempts to correlate methanogenesis rates to surfactant properties (such as the hydrophile-lipophile balance number, fatty acid carbon chain length, and the number of ethylene oxide groups) were not successful. In general, increased surfactant concentrations resulted in lower rate and extent of HCB dechlorination. Although HCB dechlorination was completely inhibited at a surfactant concentration of 1,000 mg/L, the extent of methanogenesis was not affected. Results from this study demonstrate that despite compositional similarities among the Tween surfactants, their effects on biological activities, such as methanogenesis and reductive dechlorination, can differ significantly.
Assessment of DNA damage in filamentous fungi by single cell gel electrophoresis, comet assay
Authors: Hahn Alexander , Hock Bertold 
Published: March 2010

Abstract
The single cell gel electrophoresis (SCGE) assay, or comet assay, is a highly sensitive method to measure DNA damage. The principle of the assay is based on the conversion of single-strand breaks and alkali-labile sites to double-strand breaks via alkaline lysis. The cells are subjected to electrophoresis, stained, and microscopically evaluated. Increasing damage leads to increasing migration of DNA from the nuclei. Experiments were conducted with Sordaria macrospora grown for 3 d directly on agarose minigels in order to examine the utility of the SCGE assay for the detection of effects caused by a variety of DNA-damaging agents. When the mycelia were exposed to a variety of genotoxic conditions and analyzed by SCGE, DNA strand breaks were detected by an increase in the DNA migration distance from the nucleus. The results show that this assay allows for a fast and sensitive detection of a wide spectrum of DNA-damaging effects.
Acute aquatic life criteria for selenium
Authors: Canton Steven P 
Published: March 2010

Abstract
The U.S. Environmental Protection Agency's (U.S. EPA's) current acute aquatic life criterion for selenium (Se), 20 μg/L, was based on a back-calculation from the chronic criterion of 5 μg/L, using the acute-to-chronic ratio in reverse. While bioaccumulation and subsequent toxicity through dietary uptake are important factors in chronic toxicity, acute toxicity is a shortterm phenomenon, which should be promulgated with an acute value derived from direct toxicity studies, similar to other metals and metalloids. Acute toxicity values from the U.S. EPA Se criteria document were updated with more recent toxicity data for the two primary forms of Se, selenite (Se IV) and selenate (Se VI). Using this updated toxicity database, genus mean acute values were calculated, and the database was ranked based on sensitivity to both forms. Following recalculation (using U.S. EPA criteria derivation guidelines), the updated final acute value (FAV) for selenite was 437 μg/L, resulting in a criterion maximum concentration (CMC), or acute criterion, of 219 μg/L. For selenate, the FAV becomes 826 μg/L, with a CMC of 413 μg/L. Unless Se speciation studies demonstrate that the primary form of Se is selenate, the conservative assumption should be that any Se present is in the more toxic selenite form, resulting in an acute criterion for Se of 220 μg/L. These acute criteria are scientifically sound and necessary under U.S. EPA's regulatory structure for deriving National Pollutant Discharge Elimination System discharge permit limits.
Interspecies scaling of the bioaccumulation of lipophilic xenobiotics in fish: An example using trifluralin
Authors: Schultz Irvin R , Hayton William L 
Published: March 2010

Abstract
A poorly understood factor that may influence differences in the accumulation of a xenobiotic among fishes is interspecies differences in physiology. We have extensively studied the uptake, distribution, and excretion kinetics of the lipophilic herbicide trifluralin (TF) in fish, using a static water exposure system and compartmental toxicokinetic models. We obtained quantitative estimates of physiologically based toxicokinetic parameters such as uptake clearance, apparent volume of distribution, and elimination clearance due to xenobiotic metabolism, in rainbow trout, channel catfish, and bluegill sunfish at two acclimation temperatures. In these and other species (largemouth bass, gizzard shad, fathead minnows, and lake sturgeon), oxygen consumption rate, total lipid content, plasma protein binding, and in vitro biotransformation rates from liver homogenates were determined and examined for their capacities to predict toxicokinetic parameter values. The uptake clearance of TF was predictable based on the oxygen consumption rate, and in vitro TF biotransformation rate was a useful predictor of the in vivo metabolic clearance of TF. Lipid content, however, did not predict the apparent volume of distribution of TF. Values of uptake and metabolism clearance were predicted in largemouth bass, gizzard shad, fathead minnows, and lake sturgeon, using the oxygen consumption and the in vitro TF biotransformation rates. These predicted parameters were then used to successfully simulate the toxicokinetics of TF in these species.