bluuebunny/crossref_metadata_2025_split huggingface dataset:
Integrating observational and experimental approaches to demonstrate causation in stream biomonitoring studies
Authors: Clements William H. , Carlisle Daren M. , Courtney Lisa A. , Harrahy Elisabeth A. 
Published: March 2010

AbstractRoutine biomonitoring of aquatic ecosystems generally is performed with the intent of demonstrating a causal relationship between stressors and responses. However, because it is impossible to eliminate other potential explanations for observed spatiotemporal correlation between stressors and responses, demonstrating causal relationships is highly tenuous in descriptive studies. In this research we show how results of descriptive and experimental approaches can be integrated to demonstrate a causal relationship between heavy metals and benthic community responses in a Rocky Mountain stream (CO, USA). By using a stressor identification process, we show that effects and exposure data collected from a contaminated site (Arkansas River, CO, USA) can be integrated with experimental data to support causal arguments. Analysis of the spatial co-occurrence of metals and benthic community responses in the Arkansas River provided support for the hypothesis that metals caused alterations in benthic community structure. Exposure pathways were quantified by measuring metal bioaccumulation in caddisflies (Trichoptera) collected upstream and downstream from metal inputs. A long-term (10-year) monitoring study showed that reductions in metal concentrations corresponded with improvements in benthic communities. These results were supported by microcosm and field experiments that quantified concentration-response relationships between heavy metals and benthic community composition. Consistency of these responses was demonstrated by comparing results to a spatially extensive survey of metal-polluted streams in Colorado. Our study demonstrates the power of integrating descriptive and experimental approaches for developing causal arguments in ecological assessments.
Increased toxicity to invertebrates associated with a mixture of atrazine and organophosphate insecticides
Authors: Anderson Troy D. , Lydy Michael J. 
Published: March 2010

Abstract
This study examined the joint toxicity of atrazine and three organophosphate (OP) insecticides (chlorpyrifos, methyl parathion, and diazinon) exposed to Hyalella azteca and Musca domestica. A factorial design was used to evaluate the toxicity of binary mixtures in which the lethal concentration/lethal dose (LC1/LD1, LC5/LD5, LC15/LD15, and LC50/LD50) of each OP was combined with atrazine concentrations of 0, 10, 40, 80, and 200 μg/L for H. azteca and 0, 200, and 2,000 ng/mg for M. domestica. Atrazine concentrations (&gt;40 μg/L) in combination with each OP caused a significant increase in toxicity to H. azteca compared with the OPs dosed individually. Acetylcholinesterase (AChE) activity also was examined for the individual OPs with and without atrazine treatment. Atrazine in combination with each of the OPs resulted in a significant decrease in AChE activity compared with the OPs dosed individually. In addition, H. azteca that were pretreated with atrazine (&gt;40 μg/L) were much more sensitive to the OP insecticides compared with H. azteca that were not pretreated with atrazine before being tested. Topical exposure to atrazine concentrations did not significantly increase OP toxicity to M. domestica. The results of this study indicate the potential for increased toxicity in organisms exposed to environmental mixtures.
Validation of pesticide root zone model 3.12: Employing uncertainty analysis
Authors: Carbone John P. , Havens Patrick L. , Warren-Hicks William 
Published: March 2010

Abstract
Computer models are being increasingly used to provide an efficient cost-effective means of evaluating the fate and behavior of chemicals in the environment. These models can be used in lieu of or in conjunction with field studies. Because of the increasing reliance on models for critical regulatory decision making, the need arose to assess the validity of regulatory models via an analysis of the correlation of model response estimates with measured data. In conjunction with the evaluation of the correlation of model response estimates and measured field data, a rigorous statistically based validation was also warranted. Because of the unique nature of the correlative exercise using modeled and measured data, standard statistical analyses, while informative, failed to encompass factors associated with the uncertainty of measured environmental fate data and potential model inputs. In an effort to evaluate this uncertainty, an initial sensitivity analysis was performed where key model input parameters for runoff and leaching simulations were identified. Once the sensitive input parameters were identified, a Monte Carlo-based preprocessor was developed whereby the sampling distributions of these parameters were used to propagate uncertainty in the input parameters into error in model predictions. Importantly, assumptions about parameter distributions for input into the Monte Carlo tool were made only after a formal detailed site-specific analysis of measured field data. Employing the functionality of the Crystal Ball® Pro development environment, the pesticide root zone model (PRZM) 3.12 was run iteratively for 500 trials, and model output was collated and analyzed. The model predictions were considered reasonably accurate for most regulatory requirements, and the model prediction error was considered acceptable.
A dynamic mass budget for toxaphene in North America
Authors: MacLeod Matthew , Woodfine David , Brimacombe Jenn , Toose Liisa , Mackay Don 
Published: March 2010

AbstractA continental‐scale dynamic mass budget for toxaphene in North America is presented, based on available information on physicochemical properties, usage patterns, and reported environmental concentrations and using the Berkeley‐Trent North American mass balance contaminant fate model (BETR North America). The model describes contaminant fate in 24 ecological regions of North America, including advective transport between regions in the atmosphere, freshwater, and near‐shore coastal water. The dynamic mass budget accounts for environmental partitioning, transport, and degradation of the estimated 534 million kg of toxaphene that were used in North America as an insecticide and piscicide between 1945 and 2000. Satisfactory agreement exists between model results and current and historically reported concentrations of toxaphene in air, water, soil, and sediments throughout North America. An estimated 15 million kg of toxaphene are believed to remain in active circulation in the North American environment in the year 2000, with the majority in soils in the southern United States and Mexico, where historic usage was highest. Approximately 70% of total toxaphene deposition from the atmosphere to the Great Lakes is attributed to sources outside the Great Lakes Basin, and an estimated total of 3.9 million kg of toxaphene have been transported to this region from other parts of the continent. The toxaphene mass budget presented here is believed to be the first reported continental‐scalemultimedia mass budget for any contaminant.
Development and validation of an enzyme-linked immunosorbent assay to measure vitellogenin in the zebrafish (Danio rerio)
Authors: Brion François , Nilsen Bente M. , Eidem Janne K. , Goksøyr Anders , Porcher Jean Marc 
Published: March 2010

Abstract
In this study, an enzyme-linked immunosorbent assay (ELISA) was developed to quantify vitellogenin (Vtg) in zebrafish (Danio rerio). Zebrafish Vtg (zf-Vtg) was purified from whole-body homogenates of estradiol-exposed zebrafish, and polyclonal antibodies against zf-Vtg were raised. Using purified zf-Vtg as a standard and anti-zf-Vtg antibodies (DR-264), a competitive ELISA method was set up and validated. The working range of the assay is from 1 to 30 ng/ml (20–80% binding), and the detection limit is 0.4 ng/ml for purified zf-Vtg. In whole-body homogenates samples, the practical detection limit is higher than that for purified Vtg (40 ng/ml) due to matrix effect. The intra- and interassay variations were 4.7% and 14%, respectively, at 50% binding (n = 36). Its usefulness to detect changes in Vtg concentration in other cyprinid fish was also tested. In addition, the assay was used to assess Vtg induction in male zebrafish exposed to 17β-estradiol (E2). Exposure of male zebrafish to 0.1, 1, 10, and 100 μg/L of E2 for 7 d led to a Vtg induction from the lowest concentration. The results show the suitability of the developed ELISA to quantify Vtg inductions in zebrafish, the cross-reactivity of DR264 antibodies with commonly used cyprinids, and the potential of zf-Vtg induction as a sensitive biochemical endpoint that could be used to detect estrogenic properties of chemical substances.
Trace metal distribution in soluble organic matter from municipal solid waste compost determined by size-exclusion chromatography
Authors: Kaschl Arno , Römheld Volker , Chen Yona 
Published: March 2010

Abstract
Municipal solid waste (MSW) composts carry high amounts of trace metals and organic complexing agents that may influence metal bioavailability and mobility after application to soils. In order to assess the degree of organic complexation of trace metals in the solution phase of MSW compost and the relevance of organic ligand type, size exclusion chromatography (SEC) was applied to compost-extracted organic ligands. Adjustment of the elution conditions minimized the interaction with the gel matrix for compost humic substances and dissolved organic matter (DOM) fractions. The SEC was then used to separate the aqueous compost extract into samples with distinct differences in chemical constituents. The highest quantities of Cu, Zn, Ni, Mn, and Cd were found to coelute with the main peak of the SEC elution curve, which, as observed by Fourier-transformed infrared (FTIR) spectroscopy, also had the highest density of carboxyl groups. The ratio of aromatic to aliphatic structures was higher for eluates with low retention times, and cations such as Al, Cr, and Fe were preferably associated with these larger organic molecules. All trace metals in the compost solution phase were bound mostly to DOM rather than forming inorganic complexes.
Comparison of polycyclic aromatic hydrocarbon levels in mussels and oysters in France and the United States
Authors: Beliaeff Benoit , O'Connor Thomas P. , Munschy Catherine , Raffin Bernard , Claisse Didier 
Published: March 2010

AbstractThis paper compares data of 15 individual polycyclic aromatic hydrocarbon (PAH) concentrations from two monitoring programs: the French Réseau National d'Observation de la qualité du milieu marin (RNO) and the Mussel Watch project of the U.S. National Status and Trends (NST) program. Polycyclic aromatic hydrocarbon measurements in bivalve (mussels and oysters) are made from samples collected at 265 sites along the U.S. coastline and at 97 sites in the French coastal waters. Individual PAH patterns were found strikingly similar between the two countries with higher concentrations for high-molecular-weight (HMW) PAHs. Principal component analysis results for both RNO and NST show the variability to be dominated by just two components with HMW compounds contributing primarily to the first and low-molecular-weight (LMW) compounds to the second. This could imply a separation of petrogenic and pyrolytic sources with the latter being the more important in both nations accounting for the similarity in results.
Development of a fish reporter gene system for the assessment of estrogenic compounds and sewage treatment plant effluents
Authors: Ackermann Gabriele E. , Brombacher Eva , Fent Karl 
Published: March 2010

AbstractThis study reports on the development and application of a fish-specific estrogen-responsive reporter gene assay. The assay is based on the rainbow trout (Oncorhynchus mykiss) gonad cell line RTG-2 in which an acute estrogenic response is created by cotransfecting cultures with an expression vector containing rainbow trout estrogen receptor a complementary DNA (rtERα cDNA) in the presence of an estrogen-dependent reporter plasmid and an estrogen receptor (ER) agonist. In a further approach, RTG-2 cells were stably transfected with the rtERα cDNA expression vector, and clones responsive to 17β-estradiol (E2) were selected. The estrogenic activity of E2, 17α-ethinylestradiol, 4-nonylphenol, nonylphenoxy acetic acid, 4-tert-octylphenol, bisphenol A, o,p′-DDT, p,p′-DDT, o,p′-2,2-bis(chlorophenyl)-1,1-dichloroethylene (o,p′-DDE), p,p′-DDE, o,p′-2,2-bis(chlorophenyl)-1,1-di-chloroethane (o,p′-DDD), p,p′-DDD, and p,p′-2,2-bis(chlorophenyl)acetic acid (p,p′-DDA) was assessed at increasing concentrations. All compounds except o,p′-DDT, p,p′-DDE, and p,p′-DDA showed logistic dose-response curves, which allowed the calculation of lowest-observed-effect concentrations and the concentrations at which half-maximal reporter gene activities were reached. To check whether estrogen-responsive RTG-2 cells may be used to detect the estrogenic activity of environmental samples, an extract from a sewage treatment plant (STP) effluent was assessed and found to have estrogenic activity corresponding to the transcriptional activity elicited by 0.05 nM of E2. Dose-response curves of nonylphenol, octylphenol, bisphenol A, and o,p′-DDD revealed that the RTG-2 reporter gene assay is more sensitive for these compounds when compared to transfection systems recombinant for mammalian ERs. These differences may have an effect on the calculation of E2 equivalents when estrogenic mixtures of known constitution, or environmental samples, such as STP effluents, are assessed.
Responses of benthic invertebrates to combined toxicant and food input in floodplain lake sediments
Authors: De Haas Elske M. , Reuvers Bas , Moermond Caroline T. A. , Koelmans Albert A. , Kraak Michiel H. S. 
Published: March 2010

AbstractBenthic communities in floodplain lake ecosystems are often exposed to varying levels of both food and toxicants. Inhibition through toxicants of sensitive species and stimulation through increased amounts of food of opportunistic species have been observed in separate studies. The aim of this study was therefore to assess the responses of benthic invertebrates to combined food and contamination input. Hence, seven floodplain lakes located along the River Waal, The Netherlands, with different levels of food (being either phytoplankton or macrophyte dominated) and toxicants were selected. The responses of the sensitive mayfly Ephoron virgo and the opportunistic midge Chironomus riparius to these sediments were assessed in 10-d growth bioassays with both species and a 28-d emergence experiment with C. riparius. A decrease in both survival and growth of E. virgo was observed with increasing contaminant levels. In contrast, C. riparius responded to the food quantity and quality in the sediments in spite of the toxicants present. Therefore, we conclude that the midge C. riparius is not a suitable test organism for the assessment of sediment toxicity. Alternatively, it proved to be an appropriate test organism to determine the nutritional value of sediments. The mayfly E. virgo turned out to be a much more appropriate test organism for sediment toxicity bioassays because it responds to the toxicant levels in the sediments rather than to the nutritional value. Our results demonstrate that the trophic state of an ecosystem (macrophyte or plankton dominated) influences the ecological risk of toxicants to benthic invertebrates in a species-specific way. It is concluded that not the toxicant load but the combination of food and contaminants determines the persistence of benthic invertebrates and therewith the benthic invertebrate composition in complexly polluted ecosystems.
Blood selenium concentrations and enzyme activities related to glutathione metabolism in wild emperor geese
Authors: Franson J. Christian , Hoffman David J. , Schmutz Joel A. 
Published: March 2010

Abstract
In 1998, we collected blood samples from 63 emperor geese (Chen canagica) on their breeding grounds on the Yukon-Kuskokwim Delta (YKD) in western Alaska, USA. We studied the relationship between selenium concentrations in whole blood and the activities of glutathione peroxidase and glutathione reductase in plasma. Experimental studies have shown that plasma activities of these enzymes are useful biomarkers of selenium-induced oxidative stress, but little information is available on their relationship to selenium in the blood of wild birds. Adult female emperor geese incubating their eggs in mid-June had a higher mean concentration of selenium in their blood and a greater activity of glutathione peroxidase in their plasma than adult geese or goslings that were sampled during the adult flight feather-molting period in late July and early August. Glutathione peroxidase activity was positively correlated with the concentration of selenium in the blood of emperor geese, and the rate of increase relative to selenium was greater in goslings than in adults. The activity of glutathione reductase was greatest in the plasma of goslings and was greater in molting adults than incubating females but was not significantly correlated with selenium in the blood of adults or goslings. Incubating female emperor geese had high selenium concentrations in their blood, accompanied by increased glutathione peroxidase activity consistent with early oxidative stress. These findings indicate that further study of the effects of selenium exposure, particularly on reproductive success, is warranted in this species.
Effects of ligand-bound silver on Ceriodaphnia dubia
Authors: Bielmyer Gretchen K. , Bell Russell A. , Klaine Stephen J. 
Published: March 2010

Abstract
In aqueous media, ionic silver concentrations are low and transport occurs in the colloidal phase. In the aquatic environment, silver forms 1:1 complexes with thiol-containing compounds such as cysteine and glutathione. In order to quantitatively characterize the risk associated with silver in aquatic ecosystems, the bioavailabilities and toxicities of silver cysteinate and silver glutathionate were characterized. Static renewal bioassays were conducted with Ceriodaphnia dubia to estimate chronic toxicity, using mortality and reproduction as endpoints. Silver nitrate was the most lethal compound, with a median lethal concentration (8-d LC50) of 0.32 μg Ag/L (95% confidence interval [CI] = 0.19–0.54). The 48-h LC50 for AgNO3 was 0.5 μg/L and did not change significantly through 8 d. The presence of food in the bioassay did not change the 48-h LC50 for AgNO3. Silver glutathionate (AgGSH) and silver cysteinate (AgCys) induced less mortality during the 8-d bioassay. Silver cysteinate appeared to have the greatest effect on fecundity, with a no-observable-effect concentration (NOEC) less than 0.001 μg/L. Silver nitrate and AgGSH had lowest-observable-effect concentration (LOEC) values (nominal concentrations) of 0.01 and 0.6 μg/L, respectively. Results indicate that the ligand-bound silver in these laboratory studies is bioavailable and impairs reproduction of C. dubia at low aqueous concentrations.
Effects of bisphenol a on the reproduction of Japanese medaka (Oryzias latipes)
Authors: Kang IK Joon , Yokota Hirofumi , Oshima Yuji , Tsuruda Yukinari , Oe Toshiaki , Imada Nobuyoshi , Tadokoro Hiroshi , Honjo Tsuneo 
Published: March 2010

AbstractWe elucidated the effects of bisphenol A (BPA) on the reproductive capacity (fecundity and fertility) and estrogenic response of adult Japanese medaka (Oryzias latipes) and studied the transgenerational effects (F1 generation growth and sex) of this agent on the F1 offspring. Eight mating pairs of medaka were exposed to BPA for three weeks at a measured concentration of 837, 1,720, or 3,120 μg/L. Throughout the exposure period, we observed no reduction of fecundity and fertility in any treatment group and no reduction in survival and growth or any imbalance of the sex ratio of the offspring. However, histologic examination revealed testis-ova in 13% of the males in the 837-μg/L treatment group, 86% of those in the 1,720-μg/L group, and 50% of those that received 3,120 μg BPA/L. In addition, concentrations of hepatic vitellogenin were increased significantly in males treated with BPA at 3,120 μg/L (p = 0.0148). These results suggest that BPA is a weakly estrogenic compound that has the potential to alter sexual development and induce vitellogenin in male medaka but that has no adverse effect on reproductive success.
Functional and morphological changes of lysosomes as prognostic biomarkers of toxic liver injury in a marine flatfish (Platichthys flesus (L.))
Authors: Köhler Angela , Wahl Ellen , Söffker Karin 
Published: March 2010

Abstract
Lysosomes are cell organelles in which macromolecules are recycled and that protect cells against toxins. In the present study, we apply histopathological and histochemical techniques in parallel with analytical chemistry of organochlorines and heavy metals in livers, with and without histopathological lesions, of the flatfish Plathichthys flesus (L.). The fish were caught along a pollution gradient on the German North Sea coast. We analyze critically whether changes in morphology and function of lysosomes, reflecting the onset and progression of toxipathic lesions in the liver of flounder, are appropriate for the rapid application in biological-effect monitoring programs such as BEEP (European Union Project in the 5th Framework Biological Effects of Environmental Pollutants in Marine Coastal Ecosystems). Livers collected from wild flounder were graded into four categories of lesions. Lysosomal stability was plotted against progressive lesions and contaminant levels in the same livers. Lysosomal membrane stability was already decreased at the onset of liver anomalies that are regarded as reversible. Reduced membrane stability also persisted in degenerative liver lesions and during carcinogenesis in liver parenchyma surrounding foci and tumors. Decreased lysosomal membrane stability coincided with increased size of lysosomes and increased lipid content during the progression toward degeneration. As predicted by the resistant-cell hypothesis, in proliferating cancer cells of adenomas and carcinomas, the highest values of membrane stability were detected. Concentrations of organochlorines such as hexachlorcyclohexane isomers, DDT metabolites, and polychlorinated biphenyls were correlated with reduced lysosomal membrane stability in noncancerous hepatocytes. On the basis of these findings, we recommend applying the lysosomal membrane stability test as an expertise-independent and rapid prognostic biomarker for toxically induced liver injury and carcinogenesis in monitoring programs.