bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of p-nonylphenol, methoxychlor, and endosulfan on vitellogenin induction and expression in sheepshead minnow (Cyprinodon variegatus)
Authors: Hemmer Michael J , Hemmer Becky L , Bowman Chris J , Kroll Kevin J , Folmar Leroy C , Marcovich Dragoslav , Hoglund Marilynn D , Denslow Nancy D 
Published: March 2010

Abstract
Temporal and dose-responserelationshipsofvitellogenin(VTG) mRNA nductionand subsequent plasma VTG accumulation were established for sheepshead minnows (Cyprinodon variegatus) treated with p-nonylphenol (an alkylphenol) and the organochlorine pesticides methoxychlor and endosulfan. Thirty-two adult male fish per treatment were continuously exposed to measured concentrations of 0.64, 5.4, 11.8, 23.3, and 42.7 μg/L p-nonylphenol; 1.1, 2.5, 5.6, 12.1, and 18.4 μg/L methoxychlor; and in two separate tests, 15.9, 36.3, 68.8, 162, 277, 403, 590, and 788 ng/L endosulfan using an intermittent flow-through dosing apparatus. Separate triethylene glycol (50 (μl/L) and 17β-estradiol (65.1 ng/L) treatments served as the negative and positive controls, respectively. Four fish were randomly sampled from each test concentration on days 2, 5, 13, 21, 35, and 42 of exposure, and levels of hepatic VTG mRNA induction and serum VTG accumulation were determined for each individual. Overall, fish exposed to p-nonylphenol or methoxychlor demonstrated a rapid, dose-dependent synthesis of VTG mRNA up to day 5 of exposure, followed by a relatively constant dose-dependent expression through day 42. Both chemicals showed a dose-dependent increase in plasma VTG over the entire time course of exposure, with significantly elevated VTG levels by the fifth day of exposure to p-nonylphenol at concentrations of 5.4 μg/L or greater and to methoxychlor at concentrations of 2.5 μg/L or greater. Exposure to 0.64 μg/L p-nonylphenol resulted in highly variable plasma VTG levels of less than 6 mg/ml. Exposures with endosulfan failed to induce measurable levels of either hepatic VTG mRNA or serum VTG at the chemical concentrations tested. Our results demonstrate that the sheepshead minnow bioassay is a suitable estuarine/marine teleost model for in vivo screening of potentially estrogenic substances.
A probabilistic model for silver bioaccumulation in aquatic systems and assessment of human health risks
Authors: Warila James , Batterman Stuart , Passino-Reader Dora R 
Published: March 2010

AbstractSilver (Ag) is discharged in wastewater effluents and is also a component in a proposed secondary water disinfectant. A steady-state model was developed to simulate bioaccumulation in aquatic biota and assess ecological and human health risks. Trophic levels included phytoplankton, invertebrates, brown trout, and common carp. Uptake routes included water, food, or sediment. Based on an extensive review of the literature, distributions were derived for most inputs for use in Monte Carlo simulations. Three scenarios represented ranges of dilution and turbidity. Compared with the limited field data available, median estimates of Ag in carp (0.07–2.1 μg/g dry weight) were 0.5 to 9 times measured values, and all measurements were within the predicted interquartile range. Median Ag concentrations in biota were ranked invertebrates &gt; phytoplankton &gt; trout &gt; carp. Biotic concentrations were highest for conditions of low dilution and low turbidity. Critical variables included Ag assimilation efficiency, specific feeding rate, and the phytoplankton bioconcentration factor. Bioaccumulation of Ag seems unlikely to result in toxicity to aquatic biota and humans consuming fish. Although the highest predicted Ag concentrations in water (&gt;200 ng/L) may pose chronic risks to early survival and development of salmonids and risks of argyria to subsistence fishers, these results occur under highly conservative conditions.
Probabilistic risk assessment of cotton pyrethroids: V. Combining landscape-level exposures and ecotoxicological effects data to characterize risks
Authors: Maund Stephen J , Travis Kim Z , Hendley Paul , Giddings Jeffrey M , Solomon Keith R 
Published: March 2010

AbstractSince their introduction, synthetic pyrethroid insecticides have generated regulatory concerns regarding their toxicity to fish and aquatic invertebrates. In this paper we assess the potential for risks to aquatic ecosystems in cotton-growing areas, focusing on cypermethrin as a suitable representative of the pyrethroid class and static water bodies (ponds and lakes) as worst-case water bodies because of low levels of dilution. Reviews of cypermethrin effects under laboratory and field conditions have characterized the potential aquatic effects of the chemical. Also, a landscape-level exposure characterization has been conducted in a worst-case cotton-growing county, Yazoo County, Mississippi, USA, to provide a more realistic exposure characterization than is possible using standard model scenarios. Risks were characterized using the standard tier I and II approaches of the U.S. Environmental Protection Agency. In addition, a probabilistic risk assessment was conducted by comparing landscape-level exposure calculations for ponds and lakes in Yazoo County (modified tier II analysis) with distributions of laboratory effect concentrations and with data from field studies. Risk characterization using tier I and tier II models demonstrated a level of concern for certain aquatic organisms. However, modified tier II analysis showed that exposure concentrations are unlikely to exceed concentrations that might cause ecologically significant effects. Indeed, in the vast majority of cases, concentrations in the modified tier II analysis were several orders of magnitude lower than those at which effects would be predicted on the basis of laboratory and field data. The conclusion of minimal potential for adverse ecological effects was also supported by field studies, which showed that impacts on aquatic systems were negligible, even at concentrations many times higher than the modified tier II exposure concentrations.
Effects of sulfate on the acute toxicity of selenate to freshwater organisms
Authors: Brix Kevin V , Volosin Joseph S , Adams William J , Reash Robin J , Carlton Richard G , McIntyre Dennis O 
Published: March 2010

AbstractThis study evaluated the relationship between ambient sulfate concentrations and acute selenate toxicity to freshwater aquatic life. Previous studies indicated that increasing sulfate concentrations reduced selenate bioconcentration and toxicity. However, these studies generally were not conducted in a manner that was conducive to their use in deriving a water quality criterion. We compiled results from previous studies and generated additional data to help define a selenate–sulfate relationship for acute toxicity. Selenate toxicity was determined in standardized test waters with varying sulfate concentrations using Ceriodaphnia dubia, Gammarus pseudolimnaeus, Hyalella azteca, and Pimephales promelas as the test organisms. Analysis of test results indicated that a significant relationship does exist between acute selenate toxicity and ambient sulfate concentrations. Data from these tests and previous studies were combined to develop a statistical relationship sufficiently robust to derive a sulfate-dependent water quality criterion for selenate. The relationship is similar to those commonly derived between divalent metals and hardness to adjust water quality criteria.
Dose- and time-dependent formation of biliary benzo[a]pyrene metabolites in the marine flatfish DAB (Limanda limanda)
Authors: van Schanke Arne , Holtz Frank , van der Meer Jaap , Boon Jan P , Ariese Freek , Stroomberg Gerard , van den Berg Martin , Everaarts Jan M 
Published: March 2010

Abstract
Polycyclic aromatic hydrocarbons (PAHs) are abundant pollutants, and many PAHs are carcinogenic, but only after metabolic activation. Benzo[a]pyrene (B aP) is among the most carcinogenic PAHs. The dose and time response of two enzymes involved in B aP metabolism and the amounts of B aP metabolites excreted into the bile were evaluated in an experiment with dab (Limanda limandä). Ninety dab were exposed orally to one of five doses of B aP (0, 0.08, 0.4, 2, or 10 mg/kg) and sampled at 3, 6, or 12 d after exposure. None of the doses studied caused significant induction of either microsomal ethoxyresorufin- O-deethylase (EROD), which reflects cytochrome P450 1A (CYP1A) activity, or cytosolic glutathione- S-transferase activity (GST). Concentrations of biliary B aP metabolites significantly increased with dose and significantly decreased with time after exposure. It is concluded that biliary B aP metabolites provide a much more sensitive method than EROD (CYP1A) or GST activity to monitor recent exposure to PAHs in dab.
The garden snail (Helix aspersa) as a bioindicator of organophosphorus exposure: Effects of dimethoate on survival, growth, and acetylcholinesterase activity
Authors: Coeurdassier Michaël , Saint-Denis Marine , Vaufleury Annette Gomot-de , Ribera Daniel , Badot Pierre-Marie 
Published: March 2010

Abstract
The garden snail (Helix aspersa) is currently used as bioindicator of metallic pollution. Our objective was to extend its use to organic chemicals by studying the effects and tissue concentrations of the organophosphorus pesticide dimethoate follo wing dietary uptake. After exposure for four weeks to increasing doses of pesticide in the diet, the median lethal concentration (LC50) was determined to be 3,700 μg/g food. Clinical signs indicated a no-observed-effect concentration of 100 μg/g and a lowest-observed-effect concentration of 250 μg/g. The growth parameters were decreased with increasing exposure to the pesticide. The median effective concentration (EC50), which was evaluated based on both shell diameter and dry weight inhibitions, was 665 and 424 μg/g, respectively, and the EC10 was 180 and 145 μg/g, respectively. Accumulation in the viscera was related to the amount of dimethoate in the food. The bioconcentration factors were low (&gt;6 × 10−3). Acetylcholinesterase (AChE) activity was strongly decreased (80% from 250 μg/g). In conclusion, we demonstrated that the species H. aspersa could be a useful sentinel organism for organophosphorus contamination surveys. Among the effects measured, the inhibition of AChE activities and clinical signs were the most sensitive, followed by the growth parameters. These results confirm the suitability of the garden snail for development of sublethal toxicity tests using primary consumers and aboveground organisms.
Combined effects of ultraviolet-B radiation and food shortage on the sensitivity of the Antarctic amphipod Paramoera walkeri to copper
Authors: Liess Matthias , Champeau Olivier , Riddle Martin , Schulz Ralf , Duquesne Sabine 
Published: March 2010

Abstract
Investigations on the combined effects of ultraviolet (UV)-B radiation and anthropogenic toxicants have focused primarily on the chemical interactions between UV-B and organic compounds. Only a few studies have examined whether exposure to UV-B changes sensitivity to toxicants. This question is addressed in a laboratory study using the common shoreline Antarctic amphipod Paramoera walkeri and exposure to environmentally realistic levels of copper, UV-B radiation, and food shortage. Exposure to copper for 21 d in the absence of any additional stressors (food present, no UV-B) showed a lowest observable effective concentration (LOEC) of greater than 100 μg Cu/L. Exposure to copper and UV-B in combination, with no shortage of food, resulted in a LOEC of 45 μg Cu/L. When exposed to copper and UV-B, with shortage of food, a LOEC of 3 μg Cu/L was recorded. Hence, the combination of environmental stress from exposure to UV-B radiation and shortage of food increases the sensitivity of P. walkeri to copper more than 30-fold. Increased metabolic energy requirements for defense mechanisms in response to toxicants and UV-B are discussed as possible explanations. It is concluded that consideration of environmental stressors in combination with toxicants increases the accuracy of ecological risk assessments of toxicants and should be part of the process for developing guidelines for ecologically acceptable concentrations of contaminants in the environment.
Mercury contamination and growth rate in two piscivore populations
Authors: Stafford Craig P , Haines Terry A 
Published: March 2010

Abstract
We found no relationship between fish growth rate and mercury concentration in a lake trout population and conditional support for an inverse relationship in a smallmouth bass population. A bioenergetics model indicated that mercury concentration was more responsive to dietary mercury intake than to growth rate. When biodilution is evident, it may bias contaminant versus fish size relationships.
Application of a Σpolycyclic aromatic hydrocarbon model and a logistic regression model to sediment toxicity data based on a species-specific, water-only LC50 toxic unit forHyalella azteca
Authors: Lee Jong-Hyeon , Landrum Peter F , Field L. Jay , Koh Chul-Hwan 
Published: March 2010

AbstractTwo models, a Σpolycyclic aromatic hydrocarbon (PAH) model based on equilibrium partitioning theory and a logistic-regression model, were developed and evaluated to predict sediment-associated PAH toxicity to Hyalella azteca. A ΣPAH model was applied to freshwater sediments. This study is the first attempt to use a ΣPAH model based on water-only, median lethal concentration (LC50) toxic unit (TU) values for sediment-associated PAH mixtures and its application to freshwater sediments. To predict the toxicity (i.e., mortality) from contaminated sediments to H. azteca, an interstitial water TU, calculated as the ambient interstitial water concentration divided by the water-only LC50 in which the interstitial water concentrations were predicted by equilibrium partitioning theory, was used. Assuming additive toxicity for PAH, the sum of TUs was calculated to predict the total toxicity of PAH mixtures in sediments. The ΣPAH model was developed from 10- and 14-d H. azteca water-only LC50 values. To obtain estimates of LC50 values for a wide range of PAHs, a quantitative structure-activity relationship (QSAR) model (log LC50 – log Kow) with a constant slope was derived using the time-variable LC50 values for four PAH congeners. The logistic-regression model was derived to assess the concentration–response relationship for field sediments, which showed that 1.3 (0.6–3.9) TU were required for a 50% probability that a sediment was toxic. The logistic-regression model reflects both the effects of co-occurring contaminants (i.e., nonmeasured PAH and unknown pollutants) and the overestimation of exposure to sediment-associated PAH. An apparent site-specific bioavailability limitation of sediment-associated PAH was found for a site contaminated by creosote. At this site, no toxic samples were less than 3.9 TU. Finally, the predictability of the ΣPAH model can be affected by species-specific responses (Hyalella vs Rhepoxynius); chemical specific (PAH vs DDT in H. azteca) biases, which are not incorporated in the equilibrium partitioning model; and the uncertainty from site-specific effects (creosote vs other sources of PAH contamination) on the bioavailability of sediment-associated PAH mixtures.
Testing a multimedia compartmental model with monitoring data
Authors: Pederson Beth M , Thibodeaux Louis J , Valsaraj Kalliat T , Reible Danny D 
Published: March 2010

AbstractBased on its geographic similarity and nested structure, a chemical transport and transformation model developed in The Netherlands was adopted to a nine-parish, 5,400-km2 area in southern Louisiana, USA, and tested for its ability to predict concentrations in the environment. SimpleBox 2.0 represents a class of models that compartmentalize the air, water, soil, sediment, and plants into boxes while maintaining a high degree of detail for processes within and between boxes. Past use has been in the evaluative mode, primarily where qualitative predictions of chemical behavior and distribution are made. Limited testing of model-predicted versus measured concentrations have been attempted. In recent years, quality and quantity of emission and monitoring data have improved dramatically. Such information was used in calibration and validation exercises with eight chemicals in the Louisiana chemical corridor, which receives inputs from urban, industrial, and agricultural sources. Geographically, the corridor was nested within the state of Louisiana, which was in turn nested within the continental United States. Parameter sensitivity studies, including transport coefficients, temperature, and degradation half-life revealed that the latter produces the largest range of variation in predicted concentrations. Published half-life data were used with benzene, vinyl chloride, 1,1,1-trichloethane, and atrazine in a calibration phase with 1995 monitoring data at steady state; this allowed selection of the appropriate emission database. A validation exercise was performed with toluene, styrene, trichloroethylene, and metribuzin. Predictions were compared to average measured concentrations. Atrazine and metribuzin reside primarily in the water; the others reside in the air. The predicted concentrations for benzene, metribuzin, and trichloroethylene were low by a factor of less than two. Vinylchloride, toluene, and 1,1,1-trichloroethane were low by factors between 3 and 10. Styrene and atrazine were low by factors of 45 and 65, respectively.
Substances with estrogenic activity in effluents of sewage treatment plants in southwestern Germany. 1. Chemical analysis
Authors: Spengler Peter , Körner Wolfgang , Metzger Jörg W 
Published: March 2010

AbstractA gas chromatography/mass spectrometry method for the simultaneous quantitative determination of natural and synthetic estrogens (17β-estradiol, estrone, 17α-ethinylestradiol, and mestranol), phytoestrogens (genistein and β-sitosterol), and xenoestrogens (benzyl butyl phthalate, dibutyl phthalate, bisphenol A, 4-nonylphenol [NP], 4-nonylphenoxyacetic acid [NP1EC], 4-nonyl-phenol diethoxylate [NP2EO], and α-endosulfan) in effluents of sewage treatment plants (STPs) was developed. Identification and quantification were carried out with the standard addition method using analyte-specific and, in some cases, deuterium-labeled internal standards. The effluents of 18 STPs were investigated. Apart from α-endosulfan and mestranol, all selected substances were detected in the majority of samples. The median concentrations of steroidal estrogens were between 0.4 ng/L (17α-ethiny-lestradiol) and 1.6 ng/L (17β-estradiol). The metabolites of the nonylphenol polyethoxylates, NP, NP1EC, and NP2EO were found in concentrations ranging from the upper-ng/L-range (NP) to the lower-μg/L range (NP1EC). For all substances except mestranol and α-endosulfan, median values were calculated and compared to the results of other investigations in Europe and the United States. Possible dependencies of measured concentrations on the geographical location, the capacity, the influent composition, and the technical fitting of the STPs are discussed.
Use of molecular markers to study the effects of environmental impacts on genetic diversity in brown bullhead (Ameirus nebulosus) populations
Authors: Silbiger Richard N , Leonard Anthony C , Dimsoski Pero , Foré Stephanie , Guttman Sheldon I , Roth Annette C , Gordon Denise A , Wessendarp Thomas , Toth Greg P , Smith M. Kate 
Published: March 2010

AbstractConservation biology needs sound biological information in order to maintain biological diversity in the face of the current rate of loss. An important component of the information needed is the level of genetic diversity within and between populations, especially for those species faced with exposure to environmental stressors. We applied multilocus DNA profile analysis (highly variable number tandem repeats [HVNTR] and randomly amplified polymorphic DNA [RAPD] techniques) and allozyme analysis to test whether individuals from historically degraded sites display levels of genetic diversity different from individuals taken from reference sites. Four Lake Erie tributaries, two impacted and two reference sites, were the sources of brown bullhead (Ameiurus nebulosus) samples. Pairwise comparison of the sampled populations demonstrated an association of decreased genetic diversity with exposure of brown bullhead to stressors using both RAPD and HVNTR analysis.
Detection of environmental endocrine-disruptor effects on gene expression in live Rana catesbeiana tadpoles using a tail fin biopsy technique
Authors: Veldhoen Nik , Helbing Caren C 
Published: March 2010

Abstract
We describe a novel method of rapidly assessing exposure of premetamorphic Rana catesbeiana tadpoles to endocrine-disrupting chemicals. Tail fin biopsy and reverse transcription–polymerase chain reaction analyses of the thyroid hormone (TH)–responsive gene, TH receptor β (TRβ), demonstrate for the first time that a known accelerant of TH-induced metamorphosis, acetochlor, can significantly enhance TH-induced TRβ mRNA levels within 24 h at an environmentally relevant dose. Although we focus on laboratory exposures in this study, this method easily can be adapted for use in field studies.
Relationship between soil copper content and copper content of selected crop plants in central Chile
Authors: Badilla-Ohlbaum Ricardo , Ginocchio Rosanna , Rodríguez Patricio H , Céspedes Andres , González Sergio , Allen Herbert E , Lagos Gustavo E 
Published: March 2010

AbstractA survey of copper levels in agricultural soils of central Chile revealed two soil clusters—one with a mean copper level of 162 mg/kg and one with a mean copper level of 751 mg/kg of soil. Samples of soils from both soil clusters were characterized on the basis of physicochemical characteristics, and copper extractability was compared by saturation and CaCl2 extraction as well as an acid-leaching procedure (TCLP). We also measured the copper content of various tissues of tomato (Lycopersicon esculentum) and onion (Allium cepa) crops growing on these soils. Other than copper levels, soils from the two clusters were quite similar, with slightly greater levels of molybdenum and cadmium in the high-copper soils. Within each cluster, extracted copper levels and total soil copper levels were not correlated. However, the three extraction procedures solubilized significantly more copper from the high-Cu soils. Mineralogical characterization of the soil particles and depth profiles of soil metal levels in a subsample of sites suggested that highly insoluble copper ore and mining wastes might account for the high copper levels. Neither total nor extractable copper levels allowed statistical prediction of the levels of copper in plant tissue. The edible tissues of both crops had the same mean copper content, regardless of the copper soil level. However, copper contents of stems and leaves were significantly higher for plants growing on the high-Cu soils. These results show that in these soils, high copper levels are associated with very insoluble copper species and thus low bioavailability of copper to crop plants.