bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bioaccumulation and biotransformation of 61 polychlorinated biphenyl and four polybrominated diphenyl ether congeners in juvenile American kestrels (Falco sparverius)
Authors: Drouillard Ken G. , Fernie Kimberly J. , Letcher Robert J. , Shutt Laird J. , Whitehead Megan , Gebink Wouter , Bird David M. 
Published: January 2007

Abstract—This study examined the bioaccumulation and dietary retention of 61 polychlorinated biphenyl (PCB) and four polybrominated diphenyl ether (PBDE) congeners in juvenile American kestrels (Falco sparverius). American kestrels were exposed to contaminants via egg injection and daily gavage dosing over the posthatch-to-fledgling period. Retention factors for PCBs were dependent on chemical hydrophobicity and chlorine substitution patterns and ranged from less than 1 to 16.4% for PCBs having vicinal hydrogen substitutions at meta-, para- carbons on at least one of the phenyl rings and between 13.2 and 81.5% for congeners containing chlorine substitutions at 4,4′-, 3′,4,5′-, 3,4′,5-, or 3,3′,5,5′- positions. These results indicate that juveniles are capable of biotransforming PCBs according to the same structure-activity rules as adults. A toxicokinetic model, initially parameterized using adult toxicokinetic parameters, was used to describe concentration trends in juveniles overtime. The adult model overestimated PCB concentrations but provided an adequate fit when elimination rate constants were increased by a factor of 12.7. Retention factors for the PBDE congeners 2,2′,4,4′-tetrabromodiphenyl ether (BDE 47), 2,2′,4,4′,6-pentabromodiphenyl ether (BDE 100), 2,2′,4,4′,5-pentabromodiphenyl ether (BDE 99), and 2,2′,4,4′,5,5′-hexabromodiphenyl ether (BDE 153) were from 7.8 to 45.3% of the total dose. The retention of BDE 47 was similar that observed for readily cleared PCBs, whereas the remaining PBDEs exhibited retention factors consistent with those of persistent PCBs. Half-lives for PBDEs in juveniles were estimated to range from 5.6 to 44.7 d. Assuming differences in PBDE toxicokinetics between juveniles and adults similar to those measured for PCBs, adult American kestrel PBDE half-lives are expected to range from 72 to 572 d.
Environmental estrogens suppress hormones, behavior, and reproductive fitness in male fathead minnows
Authors: Martinović Dalma , Hogarth William T. , Jones Rachel E. , Sorensen Peter W. 
Published: January 2007

Abstract—This study explored the possibility that environmental estrogens in sewage effluent may reduce the reproductive fitness of adult male fish by suppressing their reproductive behaviors, including their ability to compete for nests and females. Male fathead minnows (Pimephales promelas) were exposed for three weeks to either blank control, effluent released by a sewage treatment plant (STPE), waterborne estradiol (E2), or a synthetic androgen (methyltestosterone [MT]). Afterward, fish were placed with females and a nest, and their behavior was monitored for 5 d in either the presence or the absence of a competing (unexposed control) male. Males exposed to either the STPE or E2 (∼50 ng/L, a level chosen to mimic the estrogenic content of the STPE) had elevated levels of circulating vitellogenin (p &lt; 0.05) and lower levels of 11-ketotestosterone (KT; p &lt; 0.05). Nearly all STPE-and E2-exposed males spawned successfully in the absence of a competing male, but in both cases, exposed males suffered nearly total reproductive failure when they had to compete. Conversely, males exposed to MT (∼50 ng/L) outcompeted control males. Behavioral observations suggested that subtle differences in agonistic behaviors, typically associated with circulating androgens (i.e., KT), were responsible. We speculate that male fish exposed to estrogenic effluent in the field are less likely to reproduce successfully within large populations of wild fish, thereby causing abnormal and potentially detrimental patterns of gene flow within those populations.
Nontarget deposition and losses of oxamyl in surface runoff from flatwoods citrus production areas
Authors: Wilson Patrick Chris , Boman Brian , Foos Jane Ferguson 
Published: January 2007

Abstract
—Pesticide export from citrus production areas is a concern in the Indian River Lagoon drainage basin (Florida, USA). These studies evaluated nontarget deposition and losses of the insecticide oxamyl from typical flatwoods citrus production areas in South Florida. Deposition was estimated with the use of Teflon® spray targets placed across nontarget water furrows during spray applications. After oxamyl applications, surface water runoff events were generated with an overhead irrigation system to simulate relatively low intensity rainfall. Results indicated that 0.3 to 20.0% of the applied active ingredient landed on nontarget water furrow surfaces and that the majority of oxamyl loss occurs in runoff events shortly following application. Mean concentrations were greater during the first runoff events, ranging from 34.7 to 47.0 μg/L. Total losses during the first several hours of each set of runoff events ranged from 0.1 to 3.8% of the total active ingredient applied. Similar losses can be expected when rainfall occurs shortly after application for other pesticides with similar chemical properties and application methods.
Enantiomeric composition of chiral polychlorinated biphenyl atropisomers in dated sediment cores
Authors: Wong Charles S. , Pakdeesusuk Usarat , Morrissey Joshua A. , Lee Cindy M. , Coates John T. , Garrison Arthur W. , Mabury Scott A. , Marvin Christopher H. , Muir Derek C. G. 
Published: January 2007

Abstract—Enantiomer fractions (EFs) of seven chiral poly chlorinated biphenyls (PCBs) were measured in dated sediment cores of Lake Hartwell (SC, USA) and Lake Ontario (USA) to detect, quantify, and gain insight regarding microbial reductive dechlorination of PCBs in lake sediments with high and low concentrations, respectively. Lake Hartwell sediments had high total PCBs (5–60 μg/g), with significantly nonracemic EFs that generally were consistent with those from previous laboratory microcosm reductive dechlorination experiments using sediments from these sites. Thus, stereoselective reductive dechlorination had occurred in situ, including at total PCB concentrations of less than the threshold of approximately 30 to 80 μg/g suggested as being necessary for reductive dechlorination. Enantiomer fractions of PCBs 91, 95, 132, and 136 in Lake Hartwell cores were significantly correlated both with concentrations of those individual congeners and with total PCB concentration for some sites. This result indicates that enantioselective microbial dechlorination activity increases with higher concentrations within sediments for these congeners. Enantiomer composition reversed with depth for PCBs 91, 132, and 176, suggesting that multiple microbial populations may be present within the same core that are enantioselectively dechlorinating PCBs. Such observations indicate that concentration and time are not the only factors affecting biotransformation, complicating prediction of enantioselectivity. Comparison of EFs with dates suggested biotransformation half-lives of approximately 30 years, which is on the same time scale as sequestration by burial. In contrast, Lake Ontario sediments (maximum total PCBs, 400 ng/g) had racemic or near-racemic amounts of most congeners throughout the core profile, which is consistent with achiral indicators suggesting no microbial biotransformation within Lake Ontario sediments. Thresholds for reductive dechlorination may exist, but they would be at concentrations of less than 30 to 80 μg/g.
Metal uptake by Lolium perenne in contaminated soils using a four-step approach
Authors: Kalis Erwin J. J. , Temminghoff Erwin J. M. , Visser Anneloes , van Riemsdijk Willem H. 
Published: January 2007

Abstract
—Most research dealing with soil (solution) speciation and metal uptake by plants has focused on the relationships between a certain bioavailable fraction in the soil and metal uptake by aboveground parts of the plants. Here, a new approach to interpretation of metal uptake is presented that considers four steps: First, the metal concentration in the soil solution is related to the total metal content of the soil. Second, the metal adsorption to the root surface is related to the metal concentration in the soil solution. Third, the metal content in the roots is related to the adsorption of metal ions to the root surface. Fourth, the metal content in the shoots is related to the metal content in the roots. For grass grown on 10 different soils, it is shown that the metal adsorption to the root surface is pH-dependently related to the free or total metal concentration in the soil solution. The metal content in the roots depends linearly on the metal adsorption at the root surface, whereas the metal content in the shoots depends on the metal content in the roots, either linearly (Zn) or reaching a maximum (Cu, Pb, and Cd). For the Ni content in the shoots as a function of the root content, the relation is pH dependent, probably because of the competition effects of Ca. The pH of the soil has to be taken into account when CaCl2 extractions are used as a basis for risk assessment toward plants.
Effects of copper on sulfate reduction in bacterial consortia enriched from metal-contaminated and uncontaminated sediments
Authors: Jin Song , Drever James I. , Colberg Patricia J. S. 
Published: January 2007

Abstract—The effects of copper amendments on bacterial sulfate reduction in enrichment cultures obtained from two types of freshwater sediment were examined. Sulfate-reducing bacterial (SRB) consortia were enriched from pond sediment with no known history of metal contamination (uncontaminated) and from reservoir sediment with a well-documented history of metal contamination (metal-contaminated). The rates and extent of sulfate reduction in each sediment type in the absence of added copper were indistinguishable. With amendments of 0.8 mg/L copper, no inhibitory effects on sulfate reduction were observed in either consortium type. At 8.0 mg/L copper, activity in uncontaminated SRB consortia was significantly inhibited, as evidenced by a delay in and decreased rate of sulfate reduction; sulfidogenesis in metal-contaminated consortia was apparently unaffected. When the dissolved copper concentration was 30.0 mg/L, sulfidogenic activity in pond sediment consortia was completely inhibited. The rate of sulfate reduction temporarily decreased in the metal-contaminated enrichments but recovered after a short time. In active microcosms, copper was precipitated as CuS. The results of this study suggest that SRB from metal-contaminated environments have a markedly higher metal tolerance than those enriched from uncontaminated environments. The most significant inference from this work is that metal sulfide formation alone does not explain observed differences in metal tolerance between SRB consortia enriched from uncontaminated sediments and those that are derived from metal-contaminated sediments.
Combined use of biomarkers and in situ bioassays inDaphnia magnato monitor environmental hazards of pesticides in the field
Authors: Barata Carlos , Damasio Joana , López Miguel Angel , Kuster Marina , de Alda María López , Barceló Damià , Riva Mari Carmen , Raldúa Demetrio 
Published: January 2007

AbstractThe aim of this investigation was to evaluate toxicity effects of pesticides in aquatic invertebrates using in situ bioassays with the local species, Daphnia magna. Investigations were carried out in the Delta del Ebro (northeast Spain) during the main growing season of rice (May-August). Measures of energy consumption (i.e., algal grazing) and of specific biochemical responses (biomarkers) were conducted in individuals transplanted at four stations, including a clean site upstream of the affected area and the three main channels that collect and drain the water from the rice fields into the sea. Seventeen pesticides were analyzed in water by on-line solid-phase extraction-liquid chromatography-tandem mass spectrometry. The results obtained indicated high levels of pesticides in water, with peak values of 487 μg/L for bentazone, 8 μg/L for methyl-4-chlorophenoxyacetic acid, 5 μg/L for propanil, 0.8 μg/L for molinate, and 0.7 μg/L for fenitrothion. Measured biological responses denoted severe effects on grazing rates; a strong inhibition of cholinesterases and carboxylesterases, which are specific biomarkers of organophosphorous and carbamate pesticides; and altered patterns of the antioxidant enzyme catalase and the phase II metabolizing enzyme glutathione S-transferase. Correlation analysis with pesticide residue levels converted to toxic units relative to its acute 48-h median lethal concentration of D. magna indicated significant and negative coefficients between the dominant pesticide residues and the observed biological response, thus denoting a clear cause-and-effect relationship. The results emphasize the importance of considering specific (biomarkers) as well as more generalized and ecologically related (grazing) in situ responses to identify and evaluate biological effects of environmental contaminants in the field.
Quantification and associated variability of induced vitellogenin gene transcripts in fathead minnow (Pimephales promelas) by quantitative real-time polymerase chain reaction assay
Authors: Biales Adam D. , Bencic David C. , Flick Robert W. , Lazorchak Jim , Lattier David L. 
Published: January 2007

Abstract—Ecological risk assessors have a growing need for sensitive and rapid indicators of environmental exposures in aquatic ecosystems resulting from natural and synthetic estrogen-like compounds. Investigators developing subcellular exposure markers in traditional sentinel organisms must be vigilant about inherent variability of analyses, especially regarding regulatory and policy statements. Here, we report a quantitative real-time polymerase chain reaction (QPCR) assay for the detection of vitellogenin transcripts environmentally triggered in fathead minnows (Pimephales promelas). We demonstrate that our QPCR assay exhibits little inter- or intra-assay variability (21.7 and 11.9%, respectively). This method appears to be robust in terms of variability stemming from extrinsic sources, indicating that it may be readily transferable to laboratories having the requisite equipment. Our primary focus in development of this method derived from the observation that transcriptional responses of the vitellogenin gene (vtg) in fathead minnows demonstrated high biological variability between identically treated individuals, even under controlled laboratory conditions (coefficient of variation, &gt; 100%). This variability was not seen in other genes from the same RNA preparations that we examined, suggesting that it is specific to the vitellogenin response. Our data and those of others suggest that variability in vtg expression is common to a number of aquatic vertebrates, which is indicative of genetic causation. Despite a relatively high degree of variability in vtg transcription, this method is sensitive enough to detect exposures of 5.0 ng 17α-ethinylestradiol (EE2)/L within 24 h of exposure, and it has the ability to discriminate 10.0 and 5.0 ng EE2/L within 48 h. The vitellogenin QPCR assay is a highly sensitive, comparatively rapid, and inexpensive method for the detection and characterization of exposure to environmental estrogens and estrogen mimics.
Mineralization and plant uptake of 14C-labeled nonylphenol, nonylphenol tetraethoxylate, and nonylphenol nonylethoxylate in biosolids/soil systems planted with crested wheatgrass
Authors: Dettenmaier Erik , Doucette William J. 
Published: January 2007

Abstract
—Microcosm experiments (duration, 150 d) were conducted to evaluate the mineralization and plant uptake of [14C]nonylphenol (NP), [14C]nonylphenol tetraethoxylate (NPE4), and [14C]nonylphenol nonylethoxylate (NPE9) in a soil/biosolids (99.5:0.5 w/w) environment planted with crested wheatgrass (Agropyron cristatum). Three initial nominal concentrations (6, 24, and 47 mg/kg dry wt) each of NP, NPE4, and NPE9 were examined along with unplanted and unplanted poisoned controls. Phenol (22 mg/kg) also was evaluated as a more degradable reference compound. The biosolids were obtained from a municipal treatment plant, and the loamy sand soil was freshly collected. Mineralization ranged from 7% for NP to 53% for phenol, and no enhancement was observed in the planted systems. For NP, NPE4, and NPE9, 14C foliar tissues concentrations were proportional to exposure concentrations but were 10-fold lower than the root concentrations and two- to threefold lower than the soil concentrations. Bioconcentration factors (BCFs) based on 14C measurements ranged from 0.31 (mg compound/kg dry plant/ mg compound/kg dry soil) for systems spiked with NP to 0.52 for systems spiked with NPE9. Results of the NP analysis (initial concentration, 47 mg/kg) showed a 90% decrease in the soil concentration and an average BCF of 1.0. The lower BCF calculated from the 14C analysis likely resulted from the presence of NP transformation products in the soil that are less available or are translocated by the plants but quantified by the combustion/liquid scintillation counting procedure.
Synergism between the toxicity of chlorophenols and iron complexes
Authors: Levy Smadar , Shechtman Svetlana , Zhu Ben-Zhan , Stadtman Earl R. , Stadler Richard , Chevion Mordechai 
Published: January 2007

Abstract
—Synergistic interactions could prove to be relevant when evaluating the toxicity of environmental pollutants in a complex mixture, especially when organic and inorganic substances co-occur at concentrations currently considered to be low-toxic or sublethal. Escherichia coli cells (SR-9 strain) were used as a model system for studying the cellular toxicity of environmental pollutants. Exposure of bacterial cells to a combination of pentachlorophenol (PCP) and a positively charged complex of iron or copper caused a dramatic inhibition of growth and an increase in cell death. Incubation of bacterial cells with PCP and either ferric-1,10-phenanthroline complex [Fe3+(OP)3]3+ (500 and 5 μM, respectively) or cupric-1,10-phenanthroline complex [Cu2+(OP)2]2+ (400 and 0.05 μM, respectively) showed two and four log units of cell death, respectively, in 30 min. In contrast, only minor amounts of cell death were observed with each component alone. Similar effects have been shown for other positively charged complexes of transition metals and for other biocides. The observed synergism was associated with the formation of novel noncharged and lipophilic ternary complexes, which contain PCP anions (or other polychlorinated anions) and the iron (or copper) complex. The ternary complexes demonstrated effective transport of their components into the cells.
Using an internal standard method to determine Henry's law constants
Authors: Ji Chang , Evans Emily M. 
Published: January 2007

Abstract
—An internal standard method is developed for the measurement of thermodynamic Henry's law constants (H). In this method, a mixture of the analytes and an internal standard is prepared and used to make a standard solution (organic solvent) and a dilute aqueous solution. Both the standard solution and the headspace samples above the aqueous solution at partitioning equilibrium in closed containers are subject to gas chromatographic (GC) analysis. Subsequently, the values of H for the analytes can be calculated from the known H of the internal standard and the GC peak-area ratios. Only approximate values of the concentrations of the compounds, the GC injection volumes, and the vapor-phase to liquid-phase volume ratios in the closed containers are needed in this approach. The method works particularly well for compounds that are highly soluble in water or that have low vapor pressures. Experimentally determined values of H are reported for some low-molecular-weight aldehydes, ketones, and nitriles, and their temperature dependencies are examined. The results also are compared with literature values. The applicability of this new approach is limited to compounds that have dimensionless H on the the order of 10−3 or less.
Mitochondrial control region variation in bank voles (Clethrionomys glareolus) is not related to Chernobyl radiation exposure
Authors: Meeks Heather N. , Wickliffe Jeffrey K. , Hoofer Steven R. , Chesser Ronald K. , Rodgers Brenda E. , Baker Robert J. 
Published: January 2007

Abstract
—Three previous studies at Chernobyl, Ukraine, documented elevated mitochondrial DNA diversity in bank voles (Clethrionomys glareolus) from radioactively contaminated sites. Little evidence was found to link patterns of diversity in contaminated areas to radiation exposure, but the experimental design precluded discriminating among alternative explanations for elevated diversity in exposed groups. Reference sites selected for the studies were relatively distant from contaminated sites and, additionally, were separated from contaminated sites by large river systems; thus, we hypothesized that differences among sites were correlated with geographic isolation rather than with radiation exposure. For the present study, we added three reference sites, which were selected based on minimal radioactive contamination, proximity to contaminated sites, and absence of obvious barriers to dispersal. We hypothesized that neighboring reference sites should exhibit levels and patterns of diversity similar to those of contaminated sites if the previously detected differences were, in fact, caused by geographic isolation. Indeed, levels of diversity in nearby reference sites are comparable to levels in contaminated sites. Additionally, nearby reference sites contain several haplotypes not observed at other study sites. Our results suggest that levels of diversity in contaminated regions are more plausibly explained by ecological and historical factors than by increased mutational pressure resulting from exposure to Chernobyl radiation.
Use of anti-coronavirus antibody testing of cerebrospinal fluid for diagnosis of feline infectious peritonitis involving the central nervous system in cats
Authors: Boettcher Irene C. , Steinberg Tanja , Matiasek Kaspar , Greene Craig E. , Hartmann Katrin , Fischer Andrea 
Published: January 2007

Abstract
Objective—To assess the use of measuring anti-coronavirus IgG in CSF for the diagnosis of feline infectious peritonitis (FIP) involving the CNS in cats.
Design—Prospective study.
Sample Population—CSF and serum samples from 67 cats.
Procedures—CSF and serum samples were allocated into 4 groups: cats with FIP involving the CNS (n = 10), cats with FIP not involving the CNS (13), cats with CNS disorders caused by diseases other than FIP (29), and cats with diseases other than FIP and not involving the CNS (15). Cerebrospinal fluid was evaluated for concentrations of erythrocytes, leukocytes, and total protein. Anti-coronavirus IgG was measured in CSF and serum by indirect immunofluorescence assay.
Results—CSF IgG (range of titers, 1:32 to 1:4,096) was detected in 12 cats, including 6 cats with neurologic manifestation of FIP, 4 cats with FIP not involving the CNS, and 2 cats with brain tumors. Cerebrospinal fluid IgG was detected only in cats with correspondingly high serum IgG titers (range, 1:4,096 to 1:16,384) and was positively correlated with serum IgG titers (r = 0.652; P < 0.01), but not with any other CSF parameter. Blood contamination of CSF resulted in ≤ 333 erythrocytes/μL in cats with CSF IgG.
Conclusions and Clinical Relevance—The correlation between serum and CSF IgG and the fact that CSF IgG was detected only in strongly seropositive cats suggested that CSF anti-coronavirus IgG was derived from blood. Measurement of anti-coronavirus IgG in CSF was of equivocal clinical use.