bluuebunny/crossref_metadata_2025 huggingface dataset:
Sampling in the Great Lakes for pharmaceuticals, personal care products, and endocrine-disrupting substances using the passive polar organic chemical integrative sampler
Authors: Li Hongxia , Helm Paul A. , Metcalfe Chris D.
Published: March 2010

The passive polar organic chemical integrative sampler in the pharmaceutical configuration (i.e., pharmaceutical-POCIS) was calibrated for sampling at water temperatures of 5, 15 and 25°C to determine the influence of temperature on chemical-specific sampling rates (RS), thus providing more robust estimates of the time-weighted average concentrations of pharmaceuticals and personal care products (PPCPs) and endocrine-disrupting substances (EDS) in surface water. The effect of water temperature and flow on the RS of these analytes was evaluated in the laboratory with a static system. The loss of the test compounds from water by uptake into POCIS was linear over an 8-d period, and these experimental data yielded RS values in the range of 0.07 to 2.46 L/d across the temperature range for the 30 compounds tested. Water temperature and flow influenced POCIS uptake rates, but these effects were relatively small, which is consistent with the theory for uptake into POCIS samplers. Therefore, under a narrow range of water temperatures and flows, it may not be necessary to adjust the RS for POCIS. Except for acidic drugs and sulfonamide antibiotics, RS values were positively correlated with octanol–water partition coefficients (log KOW) of the test compounds. A linear relationship was also observed between RS and chromatographic retention times on a C18 reversed-phase column. These observations may provide a rapid method for estimating the RS of additional chemicals in the POCIS. The application of the RS to POCIS deployed for one month in Lake Ontario, Canada, during the summers of 2006 and 2008 yielded estimates of PPCP and EDS concentrations that are consistent with conventional concentration measurements of these compounds in Lake Ontario surface water. Environ. Toxicol. Chem. 2010;29:751–762. © 2009 SETAC
Leaching potential of nonsteroidal anti-inflammatory drugs in soils
Authors: Xu Jian , Wu Laosheng , Chen Weiping , Chang Andrew C.
Published: March 2010

Nonsteroidal anti-inflammatory drugs (NSAIDs) in soils resulting from application of municipal wastewater or biosolids may migrate through soils intact or be transformed and reach groundwater. In the present study, the leaching potential of four NSAIDs (ibuprofen, naproxen, ketoprofen, and diclofenac sodium) in three U.S. cropland soils was evaluated, and the effect of CaCl2 solution (as an index of salinity), dissolved organic matter (DOM), and polyacrylamide (PAM) amendment was investigated. The soils were spiked with selected NSAIDs, incubated for 24 h followed by 7-d storage in glass flasks, and then packed into stainless steel columns and leached with deionized water (DIW), 10 mM CaCl2, DOM (DOC 34 mg/L), and PAM solution (1.0 mg/L) by gravity. Initial concentrations of ibuprofen, naproxen, ketoprofen, and diclofenac sodium in the three packed soils were 1.93 to 2.07, 1.74 to 2.27, 1.79 to 2.16, and 1.99 to 2.13 mg/kg, respectively. Maximum concentrations of the above NSAIDs in column effluents were 1.23, 0.92, 0.69, and 1.12 mg/L, respectively, when the soil was leached with 10 pore volumes of water, which occupied 17.4, 11.1, 9.6, and 15.2% of the total chemicals in each soil column. Dissolved organic matter or PAM solution did not facilitate the NSAIDs release from soils. The CaCl2 solution, however, reduced the amounts of NSAIDs leached from all three soils. Leaching of NSAIDs differed among the three tested soils. The results suggest that the leaching of NSAIDs through soil to water is significant, and the mobility of NSAIDs in soil is related to their chemicals' characteristics (such as pKa values) and soil properties (such as soil organic matter and clay content). Amending soil with DOM or PAM does not significantly affect the leaching behavior of NSAIDs in soil, whereas increasing the salinity of the irrigation water may decrease the extent of contamination of groundwater posed by NSAIDs. Environ. Toxicol. Chem. 2010;29:800–807. © 2009 SETAC
Volatilization of monoaromatic compounds (benzene, toluene, and xylenes; BTX) from gasoline: Effect of the ethanol
Authors: Cagliari Jóice , Fedrizzi Francieli , Rodrigues Finotti Alexandra , Echevenguá Teixeira Cláudia , do Nascimento Filho Irajá
Published: March 2010

The main objective of present study was to assess the evaporation profile of monoaromatic compounds, namely, benzene, toluene, and xylenes (BTX) from gasoline–ethanol-blend fuels. The vapors from two river sand columns contaminated with gasoline and gasoline–ethanol were monitored for 77 d. Standards mixtures (batch tests) of benzene, toluene, and xylenes with different ethanol contents were also analyzed for evaporation rates studies. The instrumental analysis was performed via gas chromatography. The concentration of benzene in the vapor phase of the gasoline–ethanol column was decreased by 89.09%, considering the entire experimental period, whereas the toluene and xylenes concentrations were increased by 239.34 and 251.78%, respectively. In the batch tests, the benzene concentration in the vapor phase varied from 0.4 to 0.9 mg/L for ethanol concentrations (v/v) of 5 and 10%, respectively. For ethanol concentrations higher than 10%, no important changes in the benzene concentration were observed. The toluene exponentially increases between 20 and 30% ethanol concentration. and the maximum concentration of xylenes was observed when the ethanol concentration was 20% (v/v). These results suggest that the benzene evaporation behavior is preferentially affected by the interactions among ethanol and other aromatic compounds rather than the ethanol concentration itself. The evaporation behaviors of toluene and xylenes are directly dependent on the ethanol content. Environ. Toxicol. Chem. 2010;29:808–812. © 2009 SETAC
Bioaccumulation and biotransformation of pyrene and 1-hydroxypyrene by the marine whelk Buccinum undatum
Authors: Beach Daniel G. , Quilliam Michael A. , Rouleau Claude , Croll Roger P. , Hellou Jocelyne
Published: March 2010

The fates of a phenolic contaminant and its hydrocarbon precursor have rarely been compared, especially in an invertebrate species. Two groups of Buccinum undatum were exposed to equimolar amounts of pyrene and 1-hydroxypyrene over 15 d through their diets. Tissue extracts from the muscle and visceral mass were analyzed by liquid chromatography with fluorescence and mass spectrometry detection. Nine biotransformation products were detected in animals from both exposures. These included 1-hydroxypyrene, pyrene-1-sulfate, pyrene-1-glucuronide, pyrene glucose sulfate, two isomers each of pyrenediol sulfate and pyrenediol disulfate, and one isomer of pyrenediol glucuronide sulfate. These compounds represent a more complex metabolic pathway for pyrene than is typically reported. Diconjugated metabolites were as important in animals exposed to pyrene as in those exposed to 1-hydroxypyrene. Biotransformation products represented >90% of the material detected in the animals and highlight the importance of analyzing metabolites when assessing exposure. A mean of only 2 to 3% of the body burden was present in muscle compared with the visceral mass of both groups. The analytical methods were sufficiently sensitive to detect biotransformation products both in laboratory control whelks and in those sampled offshore. The tissue distribution of [14C]pyrene was also studied by autoradiography. Radioactivity was present primarily in the digestive and excretory system of the whelks and not in the gonads or muscle tissue. Environ. Toxicol. Chem. 2010;29:779–788. © 2009 SETAC
Potato (Solanum tuberosum) greenhouse tuber production as an assay for asexual reproduction effects from herbicides
Authors: Olszyk David , Pfleeger Thomas , Lee E. Henry , Plocher Milton
Published: March 2010

The present study determined whether young potato plants can be used as an assay to indicate potential effects of pesticides on asexual reproduction. Solanum tuberosum (Russet Burbank) plants were grown from seed pieces in a mineral soil in pots under greenhouse conditions. Plants were treated with herbicides (cloransulam, dicamba, glyphosate, imazapyr, primsulfuron, sulfometuron, or tribenuron) at simulated drift levels [≤0.1 × standard field application rates (f.a.r.)], approximately 14 d after emergence (DAE). Plant height was measured approximately 14 d after treatment (DAT). Production of small tubers and shoot dry weight were determined at approximately 28 DAT. Imazapyr, sulfometuron, and tribenuron caused significant reductions in tuber fresh weight, with the effective concentrations producing a 25% potato tuber fresh weight (EC25) of 0.00038, 0.0016, and 0.0021 × f.a.r. of 1,124, 52, and 9 g active ingredient hectare−1 (g a.i. HA−1), respectively. Primisulfuron, dicamba, and cloransulam also significantly reduced tuber fresh weight, but with higher EC25 values of 0.011, 0.07, and 0.010 to 0.2 × f.a.r. of 40, 558, and 18 g a.i. HA−1, respectively. Glyphosate had little effect on tuber fresh weight, with a significant reduction in only one experiment. Sulfometuron reduced tuber fresh weight at an EC25 value lower than the EC25 values for shoot dry weight or plant height. For other herbicides, the reduction in tuber fresh weight occurred within the range of EC25 values for other responses. Although additional experiments are required to develop further a phytotoxicity test, these results indicated that tuber production in young potato plants (harvested approximately 42 DAE) may be an effective assay for below-ground asexual reproductive responses to herbicides, especially acetolactate synthase inhibitors. Environ. Toxicol. Chem. 2010;29:111–121. © 2009 SETAC
Site-specific probabilistic ecological risk assessment of a volatile chlorinated hydrocarbon-contaminated tidal estuary
Authors: Hunt James , Birch Gavin , Warne Michael St. J.
Published: March 2010

Groundwater contaminated with volatile chlorinated hydrocarbons (VCHs) was identified as discharging to Penrhyn Estuary, an intertidal embayment of Botany Bay, New South Wales, Australia. A screening-level hazard assessment of surface water in Penrhyn Estuary identified an unacceptable hazard to marine organisms posed by VCHs. Given the limitations of hazard assessments, the present study conducted a higher-tier, quantitative probabilistic risk assessment using the joint probability curve (JPC) method that accounted for variability in exposure and toxicity profiles to quantify risk (δ). Risk was assessed for 24 scenarios, including four areas of the estuary based on three exposure scenarios (low tide, high tide, and both low and high tides) and two toxicity scenarios (chronic no-observed-effect concentrations [NOEC] and 50% effect concentrations [EC50]). Risk (δ) was greater at low tide than at high tide and varied throughout the tidal cycle. Spatial distributions of risk in the estuary were similar using both NOEC and EC50 data. The exposure scenario including data combined from both tides was considered the most accurate representation of the ecological risk in the estuary. When assessing risk using data across both tides, the greatest risk was identified in the Springvale tributary (δ = 25%)—closest to the source area—followed by the inner estuary (δ = 4%) and the Floodvale tributary (δ = 2%), with the lowest risk in the outer estuary (δ = 0.1%), farthest from the source area. Going from the screening level ecological risk assessment (ERA) to the probabilistic ERA changed the risk from unacceptable to acceptable in 50% of exposure scenarios in two of the four areas within the estuary. The probabilistic ERA provided a more realistic assessment of risk than the screening-level hazard assessment. Environ. Toxicol. Chem. 2010;29:1172–1181. © 2010 SETAC
Similarity, independence, or interaction for binary mixture effects of nerve toxicants for the nematode Caenorhabditis elegans
Authors: Svendsen Claus , Siang Pia , Lister Lindsay J. , Rice Annabel , Spurgeon David J.
Published: March 2010

Intensive agriculture can require the simultaneous use of more than one pesticide, resulting in the presence of mixtures in soils and waters. To assess mixture effects, concentration addition (CA) for similar acting chemicals and independent action (IA) for dissimilar acting chemicals are the most frequently used models. While the mechanistic basis for the selection of CA and IA for a given mixture appears appealing (similar vs dissimilar action), it has not yet been established how similar chemicals need to be in their effect before CA should be viewed as the most appropriate model. Here this is investigated in studies of the toxicity of binary mixtures of five different pesticides from three classes that have the same putative mode of action (neuroexcitation) but different molecular mechanisms in binary mixture tests with the nematode Caenorhabditis elegans. Effects of exposure on nematode survival were limited at the concentrations tested. Data analysis, therefore, focused on reproductive toxicity. Both CA and IA were found to be valid models for prediction of the toxicity of the 10 mixtures, although for seven CA provided a mathematically better fit. Both models could describe the toxicity for four mixtures; however, evidence for interaction was found in the remaining six cases. Where interactions occurred, these could be explained by information on the potential mechanisms of compound toxicokinetics—particularly when mixtures comprised a metabolically activated and a metabolically deactivated chemical and/or cases where the relative potencies of the two tested chemicals differed greatly. It is concluded, therefore, that detailed analysis of toxicokinetics and toxicodynamics can aid further understanding of interactions in mixtures. Environ. Toxicol. Chem. 2010;29:1182–1191. © 2010 SETAC
Chronic toxicity of fluorotelomer acids to Daphnia magna and Chironomus dilutus
Authors: Phillips Michelle M. , Dinglasan-Panlilio Mary J.A. , Mabury Scott A. , Solomon Keith R. , Sibley Paul K.
Published: March 2010

Saturated and unsaturated fluorotelomer carboxylic acids (fluorotelomer acids: FTAs) represent important intermediates in the degradation of fluorotelomer alcohols to perfluorinated carboxylic acids (PFCAs). Recent studies have detected FTAs at low concentrations (ng/L) in precipitation and surface waters; however, information regarding chronic toxicity is lacking. The present study assessed the chronic toxicity of the 8:2 saturated fluorotelomer carboxylic acid (8:2 FTCA) to Chironomus dilutus and the 10:2 saturated and unsaturated fluorotelomer carboxylic acids (10:2 FTCA and 10:2 fluorotelomer unsaturated carboxylic acid [FTuCA]) to Daphnia magna in separate life-cycle tests. In D. magna tests the FTCA was consistently more toxic than the FTuCA. Lethal concentrations (LC50s) were 150 and >60 µg/L for FTuCA and FTCA, respectively. Reproduction was significantly reduced relative to the controls, with respective median effective concentrations (EC50s) for time to first brood and mean number of offspring/female of 287 and 214 µg/L for FTuCA and 50 and 48 µg/L for FTCA. In tests with C. dilutus, EC50s for survival and growth at 20 d were 2,610 and 1,250 µg/L. Total emergence and time to first emergence, the most sensitive endpoints, yielded EC50s of 440 and 890 µg/L. Few adults emerged and no reproduction occurred at the two highest concentrations (600 and 1540 µg/L). Mean number of eggs/female was not affected. These results represent the first chronic toxicity data for FTCAs and additional evidence that FTCAs are more toxic than some PFCAs. While the results indicate that current environmental concentrations of FTAs likely pose negligible risk to aquatic biota, additional quantification of FTAs in surface waters and assessment of their toxicity is needed before meaningful assessments of potential risks to aquatic biota are possible. Environ. Toxicol. Chem. 2010;29:1123–1131. © 2010 SETAC
Heavy metals, hematology, plasma chemistry, and parasites in adult hellbenders (Cryptobranchus alleganiensis)
Authors: Huang Chuan-Chin , Xu Yi , Briggler Jeffery T. , McKee Mike , Nam Paul , Huang Yue-wern
Published: March 2010

Ozark (Cryptobranchus alleganiensis bishopi) and eastern hellbenders (C. a. alleganiensis) from seven rivers in Missouri, USA, were collected to investigate essential information on hematology, parasites, and plasma chemistry and levels of select heavy metals (Hg, Pb, Cd, Cr, and Co) in the animals' blood. The body masses of Ozark hellbenders were much smaller than those of eastern hellbenders. Blood parasites were detected in Ozark hellbenders, but not eastern hellbenders. The higher frequency in occurrence of eosinophils in Ozark hellbenders (8.8–16.8%) than in eastern hellbenders (highest at 6.6%) might result from the infection of parasites. Seven of the 18 hematology and plasma parameters (hematocrit, basophils, eosinophils, K, P, Ca, and chloride) showed significant differences between subspecies. The blood levels of heavy metals Co, Hg, and Pb differed significantly between subspecies. Ozark hellbenders had higher blood levels of Co (p < 0.001), while blood levels of Hg and Pb were higher in eastern hellbenders. The levels of chromium (Cr) and cadmium (Cd) were not different between subspecies and among rivers. The eastern hellbenders at Niangua River and the Ozark hellbenders at the North Fork of the White River had lower Hg levels compared to eastern and Ozark hellbenders at other sites. All together, our findings provide important baseline information for managing this endangered species. Environ. Toxicol. Chem. 2010;29:1132–1137. © 2010 SETAC
Perinatal exposure to bisphenol-A changes N-methyl-D-aspartate receptor expression in the hippocampus of male rat offspring
Authors: Xu Xiao-Hong , Wang Ya-Min , Zhang Jing , Luo Qing-Qing , Ye Yin-Ping , Ruan Qin
Published: March 2010

Bisphenol-A (BPA) is one of the most common environmental endocrine disrupters with mixed estrogen agonist/antagonist properties. The toxicity of BPA has been extensively evaluated in a variety of tests in rodents, including developmental and reproductive toxicity, and carcinogenicity. The objective of the present study is to evaluate whether or not perinatal maternal exposure to BPA at 0.05, 0.5, 5, 50, and 200 mg/kg/d affects N-methyl-D-aspartate (NMDA) receptor (NMDAR) subunits NR1, NR2A, 2B, estrogen receptor beta (ERβ), and aromatase cytochrome P450 (P450arom) protein expressions of hippocampus in male rat offspring during postnatal development. Western-blotting analyses showed that perinatal exposure to BPA significantly affected the expression of NMDAR subunits. At the lower doses of 0.05 to 50 mg/kg/d, BPA concentration dependently inhibited the expression of NMDAR subunits. However, at the higher dose (200 mg/kg/d), the effects of BPA on these subunits were different, with a stronger inhibition of NR1 expression and a slighter inhibition of NR2A, 2B expression when compared with those at the lower dosage of BPA. In addition, perinatal exposure to BPA inhibited the expression of ERβ protein, but increased P450arom protein expression in a concentration-dependent manner, especially during the early postnatal period (the first 1–3 postnatal weeks). No significant influence of BPA on P450arom was observed at postnatal week 8. These data suggest that environmental BPA exposure may affect the development of the brain, enhancing the local biosynthesis of estrogen in the brain, inhibiting ERβ and NMDAR expressions. Environ. Toxicol. Chem. 2010;29:176–181. © 2009 SETAC
Comparing methods for analyzing overdispersed count data in aquatic toxicology
Authors: Noe Douglas A. , Bailer A. John , Noble Robert B.
Published: March 2010

Endpoints in aquatic toxicity tests can be measured using a variety of measurement scales including dichotomous (survival), continuous (growth) and count (number of young). A distribution is assumed for an endpoint and analyses proceed accordingly. In certain situations, the assumed distribution may be incorrect and this may lead to incorrect statistical inference. The present study considers the analysis of count effects, here motivated by the Ceriodaphnia dubia reproduction study. While the Poisson probability model is a common starting point, this distribution assumes that the mean and variance are the same. This will not be the case if there is some extraneous source of variability in the system, and in this case, the variability may exceed the mean. A computer simulation study was used to examine the impact of overdispersion or outliers on the analysis of count data. Methods that assumed Poisson or negative binomially distributed outcomes were compared to methods that accommodated this potential overdispersion using quasi-likelihood (QL) or generalized linear mixed models (GLMM). If the data were truly Poisson, the adjusted methods still performed at nominal type I error rates. In the cases of overdispersed counts, the Poisson assumed methods resulted in rejection rates that exceeded nominal levels and standard errors for regression coefficients that were too narrow. The negative binomial methods worked best in the case when the data were, in fact, negative binomial but did not maintain nominal characteristics in other situations. In general, the QL and GLMM methods performed reasonably based on the present study, although all procedures suffered some impact in the presence of potential outliers. In particular, the QL is arguably preferred because it makes fewer assumptions than the GLMM and performed well over the range of conditions considered. Environ. Toxicol. Chem. 2010;29:212–219. © 2009 SETAC
Chronic, dietary polybrominated diphenyl ether exposure affects survival, growth, and development of Rana pipiens tadpoles
Authors: Cary Coyle Tawnya L. , Karasov William H.
Published: March 2010

Levels of polybrominated diphenyl ethers (PBDEs) in the environment have been increasing rapidly over the past two decades; however, the toxicology of these compounds to aquatic organisms is poorly understood. Because amphibians play a role in both aquatic and terrestrial food webs, and are currently undergoing worldwide population declines, it is of interest to determine how PBDEs may affect amphibian health. This is the first study that reports chronic, dietary effects of environmentally relevant levels (7–277 ng/g wet food) of PBDEs in amphibians throughout larval development. Beginning at the free-swimming stage (Gosner Stage [GS] 25), Rana pipiens tadpoles were orally exposed to a technical pentabromodiphenyl ether mixture (DE-71) through metamorphic climax (GS 42). On exposure day 43, a subset of tadpoles was removed for body residue analysis. Sum PBDEs in whole-body tissue correlated linearly to dietary concentrations with BDE-99 represented as the highest contributing congener in both diet and tissue. Survival among all treatments compared to the control was decreased by DE-71 exposure. Further, growth and development were delayed in all but the highest treatment, perhaps indicating greater PBDE tolerance among those individuals that survived the highest treatment. Time to metamorphic climax was delayed, on average, 22 to 36 d in DE-71-treated tadpoles compared to control tadpoles. Additionally, size at metamorphosis was smaller in the highest treatment, suggesting that individuals that survived and metamorphosed similarly to the controls did so with a trade-off in size. At environmentally relevant levels, PBDEs induced mortality as well as sublethal effects on developing tadpoles through dietary exposure. Environ. Toxicol. Chem. 2010;29:133–141. © 2009 SETAC
Direct application of biota-sediment accumulation factors
Authors: Burkhard Lawrence P. , Cook Philip M. , Lukasewycz Marta T.
Published: March 2010

In the early stages of risk assessments for sites with contaminated sediments, predictions of risks are often complicated or limited by sparse or inadequate bioaccumulation data. These limitations often require risk assessors to estimate bioaccumulation relationships in order to complete the assessments of risk. In the present study, the errors are evaluated with the simple (direct) application of field measured biota-sediment accumulation factors (BSAFs) to other species at a specific location, and to the same species and/or other species at other locations within a site and to other sites. The median (90th percentile) differences in directly applying BSAFs to other species at a specific location were ≤2.1× (≤5.1×) for fish and mussel species groups. The median (90th percentile) differences for applications across locations within a site for a specific species and to other species were ≤3.3× (≤10×) for fish, mussel, and decapod crustacean groups. For direct application across sites, slightly larger median (90th percentile) differences were observed, i.e., ≤4.0× (≤12×). The analysis was performed using a data set of 17,848 BSAFs spanning 392 chemicals/chemical combinations and 71 species. Environ. Toxicol. Chem. 2010;29:230–236. Published 2009 SETAC
Polychlorinated biphenyls, dioxins, furans, and organochlorine pesticides in belted kingfisher eggs from the upper Hudson River basin, New York, USA
Authors: Custer Thomas W. , Custer Christine M. , Gray Brian R.
Published: March 2010

Nesting belted kingfishers (hereafter kingfishers, Ceryle alcyon) were studied on the Hudson River near Fort Edward south to New Baltimore (NY, USA) and three nearby river drainages in 2004. Concentrations of 28 organochlorine pesticides, 160 polychlorinated biphenyl (PCB) congeners, and 17 dioxin and furan (PCDD-F) congeners were quantified in kingfisher eggs. The pattern of organochlorine pesticides and PCDD-F congeners did not differ significantly between 14 eggs collected from individual nests on the Hudson River and five eggs similarly collected on three other nearby rivers. In contrast, the pattern of PCB congeners in eggs collected on the Hudson River differed significantly from the other rivers. The differences in patterns of PCB congeners were associated with a higher representation of lower-numbered congeners on the Hudson River than the other rivers. The higher prevalence of the lower-numbered congeners and lower prevalence of the higher-numbered congeners is consistent with Aroclor 1016 and 1242 being the source of the PCBs on the Hudson River. Concentrations in a sample egg collected at each nest were compared to nest survival and egg success (the proportion of eggs hatching in a clutch if at least one egg hatched) of the remaining eggs in the clutch. Models that predicted nest survival and egg success as functions of contaminant levels were poorly distinguished from models that presumed no such associations. Small sample sizes could have contributed to the inability to distinguish among contaminant and no toxicant models. However, we cannot rule out the possibility that contaminant concentrations on the Hudson River were not sufficiently high to demonstrate a relationship between contaminant concentrations and reproductive success in kingfishers. Environ. Toxicol. Chem. 2010;29:99–110. Published 2009 SETAC
Observed and predicted reproduction of Ceriodaphnia dubia exposed to chloride, sulfate, and bicarbonate
Authors: Lasier Peter J. , Hardin Ian R.
Published: March 2010

Chronic toxicities of Cl−, SO 42−, and HCO 3− to Ceriodaphnia dubia were evaluated in low- and moderate-hardness waters using a three-brood reproduction test method. Toxicity tests of anion mixtures were used to determine interaction effects and to produce models predicting C. dubia reproduction. Effluents diluted with low- and moderate-hardness waters were tested with animals acclimated to low- and moderate-hardness conditions to evaluate the models and to assess the effects of hardness and acclimation. Sulfate was significantly less toxic than Cl− and HCO 3− in both types of water. Chloride and HCO 3− toxicities were similar in low-hardness water, but HCO 3− was the most toxic in moderate-hardness water. Low acute-to-chronic ratios indicate that toxicities of these anions will decrease quickly with dilution. Hardness significantly reduced Cl− and SO 42− toxicity but had little effect on HCO 3−. Chloride toxicity decreased with an increase in Na+ concentration, and HCO 3− toxicity may have been reduced by the dissolved organic carbon in effluent. Multivariate models using measured anion concentrations in effluents with low to moderate hardness levels provided fairly accurate predictions of reproduction. Determinations of toxicity for several effluents differed significantly depending on the hardness of the dilution water and the hardness of the water used to culture test animals. These results can be used to predict the contribution of elevated anion concentrations to the chronic toxicity of effluents; to identify effluents that are toxic due to contaminants other than Cl−, SO 42−, and HCO 3−; and to provide a basis for chemical substitutions in manufacturing processes. Environ. Toxicol. Chem. 2010;29:347–358. Published 2009 SETAC
Adverse outcome pathways: A conceptual framework to support ecotoxicology research and risk assessment
Authors: Ankley Gerald T. , Bennett Richard S. , Erickson Russell J. , Hoff Dale J. , Hornung Michael W. , Johnson Rodney D. , Mount David R. , Nichols John W. , Russom Christine L. , Schmieder Patricia K. , Serrrano Jose A. , Tietge Joseph E. , Villeneuve Daniel L.
Published: March 2010

Ecological risk assessors face increasing demands to assess more chemicals, with greater speed and accuracy, and to do so using fewer resources and experimental animals. New approaches in biological and computational sciences may be able to generate mechanistic information that could help in meeting these challenges. However, to use mechanistic data to support chemical assessments, there is a need for effective translation of this information into endpoints meaningful to ecological risk—effects on survival, development, and reproduction in individual organisms and, by extension, impacts on populations. Here we discuss a framework designed for this purpose, the adverse outcome pathway (AOP). An AOP is a conceptual construct that portrays existing knowledge concerning the linkage between a direct molecular initiating event and an adverse outcome at a biological level of organization relevant to risk assessment. The practical utility of AOPs for ecological risk assessment of chemicals is illustrated using five case examples. The examples demonstrate how the AOP concept can focus toxicity testing in terms of species and endpoint selection, enhance across-chemical extrapolation, and support prediction of mixture effects. The examples also show how AOPs facilitate use of molecular or biochemical endpoints (sometimes referred to as biomarkers) for forecasting chemical impacts on individuals and populations. In the concluding sections of the paper, we discuss how AOPs can help to guide research that supports chemical risk assessments and advocate for the incorporation of this approach into a broader systems biology framework. Environ. Toxicol. Chem. 2010;29:730–741. © 2009 SETAC
Predicting mercury concentrations in mallard eggs from mercury in the diet or blood of adult females and from duckling down feathers
Authors: Heinz Gary H. , Hoffman David J. , Klimstra Jon D. , Stebbins Katherine R.
Published: March 2010

Measurements of Hg concentrations in avian eggs can be used to predict possible harm to reproduction, but it is not always possible to sample eggs. When eggs cannot be sampled, some substitute tissue, such as female blood, the diet of the breeding female, or down feathers of hatchlings, must be used. When female mallards (Anas platyrhynchos) were fed diets containing methylmercury chloride, the concentration of Hg in a sample of their blood was closely correlated with the concentration of Hg in the egg they laid the day they were bled (r2 = 0.88; p < 0.001). Even when the blood sample was taken more than two weeks after an egg was laid, there was a strong correlation between Hg concentrations in female blood and eggs (r2 = 0.67; p < 0.0002). When we plotted the dietary concentrations of Hg we fed to the egg-laying females against the concentrations of Hg in their eggs, the r2 value was 0.96 (p < 0.0001). When the concentrations of Hg in the down feathers of newly hatched ducklings were plotted against Hg in the whole ducklings, the r2 value was 0.99 (p < 0.0003). Although measuring Hg in eggs may be the most direct way of predicting possible embryotoxicity, our findings demonstrate that measuring Hg in the diet of breeding birds, in the blood of egg-laying females, or in down feathers of hatchlings all can be used to estimate what concentration of Hg may have been in the egg. Environ. Toxicol. Chem. 2010;29:389–392. Published 2009 SETAC
Sediment toxicity and bioaccumulation of nano and micron-sized aluminum oxide
Authors: Stanley Jacob K. , Coleman Jessica G. , Weiss Charles A. , Steevens Jeffery A.
Published: March 2010

Nano-aluminum oxide (Al2O3) is used commercially in coatings and abrasives. Nano-Al2O3 can also be generated through the oxidation of nano-aluminum in military propellants and energetics. The purpose of the present study was to assess toxicity and bioaccumulation of nano-Al2O3 to a variety of sediment organisms (Tubifex tubifex, Hyalella azteca, Lumbriculus variegatus, and Corbicula fluminea). The bioaccumulation and toxicity of nano-Al2O3 was compared with that of micron-sized Al2O3 to investigate potential size-related effects. Results of the present study show species-specific differences in relative bioaccumulation of nano and micron-sized Al2O3. Significant toxic effects (survival and growth) were observed in H. azteca testing, but only at high concentrations unlikely to be found in the environment. Nano-Al2O3 was found to be more toxic than micron-sized Al2O3 to H. azteca survival in a 14-d study in which organisms were in direct contact with a thin layer of 625 or 2,500 mg of Al2O3 dispersed on the surface of either sediment or sand. A significant growth effect was also observed for nano but not micron-sized Al2O3 at the highest treatment level tested (100 g/kg Al2O3) in a 10-d H. azteca bioassay in which Al2O3 was homogenized with sediment. However, differences in measured sediment Al concentrations (micron-sized = 55.1 [±0.6] g/kg Al; nano-sized = 66.2 [±0.6] g/kg Al) in the nano and micron-sized Al2O3 preclude direct comparison of the toxicity of these two treatments based on particle size. Environ. Toxicol. Chem. 2010;29:422–429. © 2009 SETAC
A new method for ranking mode-specific sensitivity of freshwater arthropods to insecticides and its relationship to biological traits
Authors: Rubach Mascha N. , Baird Donald J. , Van den Brink Paul J.
Published: March 2010

The problem of how to deal with species sensitivity differences to toxic substances has been addressed successfully with the species sensitivity distribution (SSD), yet this has not increased understanding about the underlying mechanisms of sensitivity. Other researchers have identified the mode of action of chemicals and also biological traits of species as determinants for sensitivity, yet no systematic approach combines these factors. To achieve this, first existing data on organophosphate, carbamate, and pyrethroid toxicity and mode of action and also species trait information were mined. Second, we linked taxon sensitivity to their traits at the family level to generate empirical and mechanistic hypotheses about sensitivity–trait relationships. In this way, a mode-specific sensitivity (MSS) ranking method was developed, and tested at the taxonomic level of family and genus. The application of several quality criteria indicated overall confidence in rankings, but confidence in exact taxon rank was less certain, due to data insufficiency for certain groups. The MSS rankings were found to be applicable for trait-based approaches and were successfully linked to existing trait data to identify traits with predictive potential. Although this empirical analysis cannot test causality relationships between traits and sensitivity, testable hypotheses were generated, for further experimental investigation. Single traits as well as combinations of traits can be used to predict laboratory sensitivity to the substances tested, although associations were not as strong as in previous studies. We conclude that existing trait data are not suitable for every trait-based research question and that important traits remain to be identified and quantified in relation to the processes of toxicity, i.e., the toxicokinetics and toxicodynamics. Environ. Toxicol. Chem. 2010;29:476–487. © 2009 SETAC
Aquatic toxicity of magnesium sulfate, and the influence of calcium, in very low ionic concentration water
Authors: van Dam Rick A. , Hogan Alicia C. , McCullough Cherie D. , Houston Melanie A. , Humphrey Chris L. , Harford Andrew J.
Published: March 2010

The toxicity of magnesium sulfate (MgSO4), and the influence of calcium (Ca), were assessed in very soft freshwater (natural Magela Creek water [NMCW]) using six freshwater species (Chlorella sp., Lemna aequinoctialis, Amerianna cumingi, Moinodaphnia macleayi, Hydra viridissima, and Mogurnda mogurnda). The study involved five stages: toxicity of MgSO4 in NMCW, determination of the toxic ion, influence of Ca on Mg toxicity, toxicity of MgSO4 at an Mg:Ca mass ratio of 9:1, and derivation of water quality guideline values for Mg. The toxicity of MgSO4 was higher than previously reported, with chronic median inhibition concentration (IC50)/acute median lethal concentration (LC50) values ranging from 4 to 1,215 mg/L, as Mg. Experiments exposing the 3 most sensitive species (L. aequinoctialis, H. viridissima, and A. cumingi) to Na2SO4 and MgCl2 confirmed that Mg was the toxic ion. Additionally, Ca was shown to have an ameliorative effect on Mg toxicity. For L. aequinoctialis and H. viridissima, Mg toxicity at the IC50 concentration was eliminated at Mg:Ca (mass) ratios of ≤10:1 and ≤9:1, respectively. For A. cumingi, a 10 to 30% effect persisted at the IC50 concentration at Mg:Ca ratios <9:1. The toxicity of MgSO4 in NMCW at a constant Mg:Ca ratio of 9:1 was lower than at background Ca, with chronic IC50/acute LC50 values from 96 to 4,054 mg/L, as Mg. Water quality guideline values for Mg (to protect 99% of species) at Mg:Ca mass ratios of >9:1 and ≤9:1 were 0.8 and 2.5 mg/L, respectively. Magnesium can be toxic at concentrations approaching natural background levels, but toxicity is dependent on Ca concentrations, with exposure in very low ionic concentration, Ca-deficient waters posing the greatest risk to aquatic life. Environ. Toxicol. Chem. 2010;29:410–421. Published 2009 SETAC
Review: Environmental chemistry: An overview
Authors: Crosby Donald G.
Published: March 2010

Environmental Chemistry describes the world around us — a dynamic world of chemicals which become distributed between earth, water, atmosphere, and biota and transformed by natural reagents. The subject is far from new; until the age of synthetics, chemistry itself was based predominantly on the natural environment. Its present renaissance has been stimulated largely by the promise of assessment and control of toxic hazards and pollution, but the predictability, novel chemistry, and wide applications already apparent may prove at least as important. Just as synthetic chemistry revolutionized the lives of recent generations, environmental chemistry can provide a better future for all Earth's inhabitants.
An approach to scoring of toxic chemicals for environmental effects
Authors: Welch Justine L. , Ross Robert H.
Published: March 2010

The systematic scoring of chemicals is a tool to assist in the consistent comparison and ordering of the universe of industrial chemicals. Scoring at an early stage of assessment could identify most of the chemicals that have a high probability for requiring review for possible control or testing. This report describes the results of a three-day workshop held in Washington, D.C., August 13–15, 1979, to develop a system to select chemicals for preliminary assessments according to their hazard to the environment. The system combines environmental release and distribution potential with mobility and persistence scores in the three environmental media, air, soil, and water. The components of the environmental exposure score are then combined with toxicity by using multipliers (3x, 2x, or 1x) which are assigned on the basis of the concentration at which an adverse effect in environmental species is observed. The system requires minimal information inputs, relies on expert professional judgement and is recognized as an initial phase of selecting candidates for additional assessment.
Uptake and distribution of C12 alkylbenzene in bluegill (Lepomis macrochirus)
Authors: Werner A. Frances , Kimerle Richard A.
Published: March 2010

The Bioconcentration Factor (BCF) for [14C)] Alkylbenzene in Bluegill Sunfish (Lepomis machrochirus, Rafinesque] was determined to be 35. The value is significantly smaller than the predicted BCF of 6300; the discrepancy is ascribed to metabolism. Alkylbenzene has similar patterns of tissue distribution and depuration rates when compared to its sulfonated counterpart, linear alkylbenzene sulfonate, which has been shown to be readily metabolized.
The effect of chronic cadmium exposure on phosphoadenylate concentrations and adenylate energy charge of gills and dorsal muscle tissue of crayfish
Authors: Dickson Gary W. , Giesy John P. , Briese Linda A.
Published: March 2010

The sensitivity of two measures of tissue energy metabolism to environmental stress was examined in the present study through chronic exposure of crayfish to low concentrations of cadmium. Freshwater crayfish, Procambarus acutus acutus, were exposed to 5 and 10 μ Cd · 1 (as CdCl2) under flow-through conditions for a period of 21 days. After 1, 7, 14, and 21 days of exposure, gill and dorsal muscle tissue samples were collected to determine Cd and Zn content. phosphoadenylate (ATP, ADP and AMP) concentrations and gill tissue respiration rates. Two potential sublethal stress indicators, the adenylate energy charge [AEC = (ATP + 1/2 ADP)/ (ATP + ADP + AMP)] and ATP turnover rate were calculated. Cd was observed to concentrate over time in gills, but not in muscle tissue. No evidence was found to indicate replacment of Zn by Cd in the tissues analyzed. In addition, Cd tissue concentrations were not correlated (p > 0.05) with phosphoadenylate concentrations or respiration rate. After seven days exposure, ATP and total phosphoadenylate concentrations in gill tissue were significantly (p < 0.05) lower in crayfish exposed to Cd. This decrease was associated with lower gill tissue respiration rates, probably due to enzyme dysfunction caused by Cd. The return of ATP concentrations and gill tissue respiration rates to control values observed after day 7 may be associated with the induction of replacement enzymes and metallothioneins stimulated by Cd. ATP turnover rate (based on 1 mole O2 ← 6 moles ATP) in gill tissue was not correlated (p > 0.05) with the two measures of aerobic respiration recorded, and was not considered to represent an accurate indication of cellular energy turnover. In contrast to an earlier study utilizing a different crayfish species, no significant (p > 0.05) decreases in tissue AEC were observed in the present study in crayfish exposed to Cd. The absence of AEC changes under the exposure conditions imposed in this investigation could be related to life history differences or in species specific sensitivity to the toxic effects of Cd. Under the experimental conditions utilized, the adenylate energy charge and ATP turnover rate did not provide indications of Cd toxicity at lower concentrations than those previously determined through conventional chronic lethality testing. However, these physiological indicators did permit a more complete understanding of the toxic action of cadmium on the tissues examined.
Ecosystem risk analysis: A new methodology
Authors: O'Neill R. V. , Gardner R. H. , Barnthouse L. W. , Suter G. W. , Hildebrand S. G. , Gehrs C. W.
Published: March 2010

A method is presented for extrapolating laboratory toxicity data to aquatic ecosystem effects such as decreased productivity or reduction in game fish biomass. The extrapolation requires translating laboratory data into changes in the parameters of an ecosystem model, the Standard WAter COlumn Model (SWACOM). The translation is effected through knowledge of toxicological modes of action. The uncertainties associated with both laboratory measurements and extrapolations are explicitly retained, and risk estimates are given in the form of probabilities that an effect could occur. The approach is illustrated by scenarios in which effects of toxic substances are distributed across different trophic levels. Each scenario affects population interactions in different ways and alters both the level and the nature of the risks to ecosystem processes. Particular attention is paid to analyzing the interaction between toxicity and the uncertainties associated with extrapolation.
Toxicity of three preparations of pentachlorophenol to fathead minnows -A—comparative study
Authors: Cleveland Laverne , Buckler Denny R. , Mayer Foster L. , Branson Dean R.
Published: March 2010

The toxicity of three samples of pentachlorophenol (PCP) containing various impurities was evaluated in 90-d, partial life-cycle toxicity studies with fathead minnows (Pimephales promelas Rafinesque). Samples of purified PCP, Dowicide EC-7, and a composite of commercial PCP were used in the studies. The exposure concentrations were 10 to 142 μg/L of the purified PCP; 8 to 139 μg/L of the Dowicide EC-7; and 6 to 121 μg/L of the commercial composite of PCP. The purified PCP contained relatively high amounts of chlorinated phenoxyphenols; Dowicide EC-7 contained more types of impurities, but generally at lower concentrations than in either the purified PCP or the commercial composite; and the commercial composite contained relatively large quantities of hexachlorobenzene, chlorinated phenoxyphenols, chlorinated dibenzodioxins, and chlorinated dibenzofurans.

Concentrations of the purified PCP equal to or greater than 85 μg/L reduced the growth of the fathead minnows but did not adversely affect survival. Dowicide EC-7 concentrations as high as 139 μg/L did not adversely affect growth or survival of fathead minnows. The commercial composite of PCP reduced growth at concentrations of 13 μg/L or higher and reduced survival at concentrations of 27 μg/L or higher. Degeneration of the fins and opercles, and malformations of the anterior regions of the skull were also noted in fathead minnows exposed to the commercial composite of PCP. Impurities clearly increased the toxic effects of PCP in fathead minnows.
Inhalation toxicology: Starting with the environment
Authors: Dorough H. Wyman
Published: March 2010

The theme of SETAC's Second Annual Meeting was Environmental Risk Assessment, with emphasis on the use of data in the risk assessment and overall decision making process for chemicals. Needs for specific types of data were emphasized by the theme of the meeting and in no area was the void more obvious than in inhalation toxicology. Sufficient information for decision making in this area simply is not available, and no better combination of expertise exists for making judgments of risk than that of the environmental and mammalian toxicologists. To foster further communication between the two, a symposium was held in which experienced mammalian-oriented toxicologists were asked to address the state-of-the-art of inhalation toxicology for the benefit of those more oriented toward the traditional environmental toxicology area. Papers for the symposium are published herein to encourage continued efforts by all toxicologists to share in the data development and decision making process essential for healthy humans to enjoy a quality environment. The present paper is introductory in nature but utilizes recent findings in the author's laboratory concerning inhalation exposure and retention of chemical vapors in rats to demonstrate the rationale for selecting other topics for presentation.