bluuebunny/crossref_metadata_2025_split huggingface dataset:
A micelle inhibition model for the bioavailability of polycyclic aromatic hydrocarbons in aquatic systems
Authors: Park Seok S. , Park Jae-Woo , Uchrin Christopher , Cheney Marcos A. 
Published: March 2010

Abstract
A mathematical model was developed to quantify micelle suppression on the bioavailability of hydrophobic organic compounds in aquatic systems. The model was based on a three-compartment dynamic system in which the hydrophobic compounds are taken up and eliminated by organisms with an equilibrium partitioning between water and micelle. The model was validated against data obtained from in vitro studies of the bioaccumulation of naphthalene, anthracene, and chrysene into the gills of the freshwater mussel (Ellipto complanata) in the presence of a surfactant (Tween 80). The model predictions agreed well with the experimental results for all three chemicals. Sensitivity analyses were performed to examine model responses to the surfactant parameters. From the model, we derive an equation for a bioconcentration factor in aquatic surfactant systems to predict the maximum concentration of polycyclic aromatic hydrocarbons (PAHs) in aquatic organisms. From these results, we also propose a micelle inhibition factor for bioconcentration that is a function of the surfactant concentration, critical micelle concentration, and partition coefficient of hydrophobic compounds between water and micelle. Knowledge of these parameters may improve understanding of the partitioning of PAHs into organisms in the presence of surfactants.
Dietary accumulation of perfluorinated acids in juvenile rainbow trout (Oncorhynchus mykiss)
Authors: Martin Jonathan W. , Mabury Scott A. , Solomon Keith R. , Muir Derek C. G. 
Published: March 2010

AbstractPerfluorinated acids (PFAs) recently have emerged as persistent global contaminants after their detection in wildlife and humans from various geographic locations. The highest concentrations of perfluorooctane sulfonate are characteristically observed in high trophic level organisms, indicating that PFAs may have a significant bioaccumulation potential. To examine this phenomenon quantitatively, we exposed juvenile rainbow trout (Oncorhynchus mykiss) simultaneously to a homologous series of perfluoroalkyl carboxylates and sulfonates for 34 d in the diet, followed by a 41-d depuration period. Carcass and liver concentrations were determined by using liquid chromatography-tandem mass spectrometry, and kinetic rates were calculated to determine compound-specific bioaccumulation parameters. Depuration rate constants ranged from 0.02 to 0.23/d, and decreased as the length of the fluorinated chain increased. Assimilation efficiency was greater than 50% for all test compounds, indicating efficient absorption from food. Bioaccumulation factors (BAFs) ranged from 0.038 to 1.0 and increased with length of the perfluorinated chain; however, BAFs were not statistically greater than 1 for any PFA. Sulfonates bioaccumulated to a greater extent than carboxylates of equivalent perfluoroalkyl chain length, indicating that hydrophobicity is not the sole determinant of PFA accumulation potential and that the acid function must be considered. Dietary exposure will not result in biomagnification of PFAs in juvenile trout, but extrapolation of these bioaccumulation parameters to larger fish and homeothermic organisms should not be performed.
Influence of dietary sodium on waterborne copper toxicity in rainbow trout,Oncorhynchus mykiss
Authors: Kamunde Collins N. , Pyle Greg G. , McDonald D. Gordon , Wood Chris M. 
Published: March 2010

AbstractJuvenile rainbow trout were fed diets containing control (0.26 mmol/g) or elevated (1.3 mmol/g) dietary Na+ in combination with either background (19 nmol/L) or moderately elevated levels (55 or 118 nmol/L) of waterborne Cu for 21 d. Unidirectional waterborne Na+ uptake rates (measured with 22Na) were up to four orders of magnitude higher than those of Cu (measured with 64Cu). Chronic exposure to elevated dietary Na+ alone or in combination with elevated waterborne Cu decreased whole-body uptake rates of waterborne Na+ and Cu. Accumulation of new Cu and Na+ at the gills was positively and highly significantly correlated and responded to the experimental treatments in a similar fashion, suggesting that Na+ and Cu have common branchial uptake pathways and that dietary Na+ preexposure modifies these pathways. Chronic exposure to elevated waterborne Cu significantly increased Cu concentrations in the liver but caused only modest increases in total Cu concentrations in the whole body and gill. Chronic exposure to elevated dietary Na+ slightly decreased whole-body Cu concentration on day 14 and greatly reduced liver Cu concentration on days 14 and 21; new Cu accumulation in whole-body, gill, and internal organs was reduced on all days. Chronic exposure to elevated waterborne Cu or dietary Na+ alone reduced short-term gill Cu binding at low waterborne Cu concentrations. At high waterborne Cu concentrations, chronic exposure to elevated waterborne Cu had no effect, while elevated dietary Na+ increased Cu binding to the gills. Combined chronic exposure to elevated dietary Na+ and waterborne Cu decreased gill Cu binding over the entire range of Cu concentrations tested. Clearly, chronic exposure to elevated dietary Na+ and waterborne Cu appears to modify gill Cu-binding characteristics and may be important considerations in future development of a chronic biotic ligand model for Cu.
Multiple computer-automated structure evaluation study of aquatic toxicity. III. Vibrio fischeri
Authors: Klopman Gilles , Stuart Scott E. 
Published: March 2010

Abstract
An acute toxicity model was constructed on the basis of 901 chemicals tested for toxicity against the luminescent bacteria Vibrio fischeri (formerly Photobacterium phosphoreum, the Microtox® test). The model was created using the Multiple Computer-Automated Structure Evaluation (M-CASE) program. The model can correctly predict acute toxicity for 92% of the compounds with an error averaging 0.55 log units per median effect concentration (EC50). The main toxicophores, corresponding to polar and nonpolar narcosis, and other types of reactive chemicals were identified.
Ranking contaminated sites using a partial ordering method
Authors: Jensen Trine S. , Lerche Dorte B. , Sørensen Peter B. 
Published: March 2010

Abstract
In this project, we apply the method of partial ordering on the ranking of 74 contaminated sites located in the county of West Zealand (Denmark). The method is based on the concept that the parameters are kept separated through the ranking analysis, and thus no weighing of the different parameter values is necessary. The ranking is displayed in a graphical form by the Hasse diagram technique to ease the interpretation. A critical comparison is made of the ranking of contaminated sites by the partial ordering method and an index function used by the county of West Zealand. Comparing the ranking by the partial ordering method to the index function shows that the choice of score points and index function highly influences the ranking result, as only four sites are equally ranked. The importance of the parameters used to identify the environmental hazard of the contaminated sites is analyzed in order to evaluate the influence of each parameter on the ranking. From among a total of six different parameters, two have high influence, two medium, and two low because of both the construction of the scoring system and the characteristics of the data.
Prediction of ecological no-effect concentrations for initial risk assessment: Combining substance-specific data and database information
Authors: Roelofs Willem , Huikbregts Mark A. J. , Jager Tjalling , Ragsas Ad M. J. 
Published: March 2010

Abstract
A new method is proposed to derive predicted no-effect concentrations (PNECs) for initial risk assessments for aquatic ecosystems from a limited set of single-species toxicity data. The method includes three steps. First, acute toxicity data are divided by an acute-to-chronic assessment factor to obtain chronic toxicity data. Subsequently, chronic toxicity data are averaged to obtain an average hazardous concentration (HC50). Finally, the HC50 is divided by an interspecies assessment factor to obtain a PNEC. Both assessment factors are derived as probability distributions from an extensive ecotoxicological database. The interspecies assessment factor is combined with substance-specific toxicity data using Bayesian statistics. The proposed method optimizes the use of the available ecotoxicological information and it produces an uncertainty estimate of the PNEC. Sample calculations indicate that the proposed method may provide a good alternative for currently applied methods for initial risk assessment, particularly if few toxicity data are available.
Pyrene metabolism in the springtail Orchesella cincta L. (Collembola, Entomobryidae)
Authors: Howsam Mike , Van Straalen Nico M. 
Published: March 2010

Abstract
A novel, solvent-free spiking method was used to contaminate foodstuff (Desmococcus spp. algae) with pyrene for bioassays with the springtail Orchesella cincta L. (Collembola, Entomobryidae). The primary metabolite 1-hydroxypyrene and two conjugates (pyrene-1-glucoside and one tentatively identified as pyrene-1-glucosidemalonate) were quantified in the insects by high-performance liquid chromatography (HPLC) with fluorescence detection. Individuals from an unpolluted site (SUS population) were capable of rapid metabolism of pyrene, reaching an apparent steady state after 24 h with a composite assimilation/transformation rate of approximately 25 pmol pyrene · g−1 fresh weight · h−1 at an exposure level of approximately 18 μg pyrene · g−1 dry weight algae. A cadmium (Cd)-tolerant population (TOL), genetically distinct from SUS, was exposed in parallel and the populations' pyrene metabolism compared in order to gain insight into any potential cost of Cd-tolerance. The TOL animals assimilated and/or performed phase 1 transformation of pyrene approximately twice as fast as SUS (∼56 pmol · g−1 · h−1), but there was no significant difference in the elimination rate constants between SUS and TOL animals. Attributing this difference to any specific cost of Cd-tolerance requires more work and may be coincidental to metal tolerance, but pyrene metabolism in these distinct genotypes, subjected to different selection pressures, was nevertheless significantly different.
Effects of mercury on reproduction, avoidance, and heat shock protein gene expression of the soil springtailFolsomia candida
Authors: Liu Yu-Rong , Zheng Yuan-Ming , Zhang Li-Mei , Luan Yun-Xia , He Ji-Zheng 
Published: March 2010

AbstractBased on the Cambisols of Beijing (used as agricultural soils), toxicity tests were conducted to investigate the effects of mercury (Hg) on reproduction and avoidance of Folsomia candida (Hexapoda: Collembola), as well as the transcriptional responses of the hsp70 gene, under different Hg concentrations and at different exposure times. Results showed that the hsp70 gene of the springtail was the most sensitive parameter to soil Hg stress, with a half-maximal effective concentration (EC50) of 0.42 mg/kg. The EC50 values based on reproduction and avoidance tests were 9.29 and 3.88 mg/kg, respectively. The expression level of the hsp70 gene was significantly up-regulated when soil Hg concentration was over 0.25 mg/kg (lowest-observed-effect concentration [LOEC]). In addition, responses of this gene expression were strongly induced after 48 h exposure under 1 mg/kg soil Hg, which probably was due to the fast and sensitive response of the gene transcription to Hg stress. Thus, the results suggested that the responses of the hsp70 gene and individual-level effects (reproduction and avoidance) could be integrated to provide helpful information for environmental monitoring and assessment of contaminated soils. Environ. Toxicol. Chem. 2010;29:654–659. © 2009 SETAC
Polluted-site killifish (Fundulus heteroclitus) embryos are resistant to organic pollutant-mediated induction of CYP1A activity, reactive oxygen species, and heart deformities
Authors: Arzuaga Xabier , Elskus Adria 
Published: March 2010

Abstract
Exposure to coplanar polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) can adversely affect fish embryonic development, induce expression of cytochrome P4501A (CYP1A), and increase reactive oxygen species (ROS) production, effects believed to be mediated by the aryl hydrocarbon receptor (AHR). Killifish (Fundulus heteroclitus) populations in New Bedford Harbor, Massachusetts, USA (NBH) and Newark Bay, New Jersey, USA (NB) are generationally exposed to coplanar PCBs and PAHs and have developed resistance to PCB mediated induction of CYP1A. We hypothesized that fish resistant to CYP1A induction would also exhibit resistance to PCB and PAH induced ROS production and teratogenesis. Killifish embryos from two contaminated (NB, NBH) and two reference-site populations were exposed to vehicle or 3,3′4,4′5-pentachlorobiphenyl (PCB126) or 3-methylcholanthrene (3-MC) and evaluated for in ovo CYP1A activity, heart deformities, and ROS production. Both chemicals significantly increased in ovo ethoxyresorufin-O-deethylase (EROD) and ROS production in reference-site embryos. These chemicals provoked only moderate induction of in ovo EROD in NBH and NB embryos, and neither PCB126 nor 3-MC induced ROS production in these populations. Similarly, heart deformities were significantly induced by PCB126 in reference-site embryos, but had no significant effects on NB and NBH animals. These results indicate that fish resistant to CYP1A induction also exhibit decreased sensitivity to PCB126 and 3-MC-induced ROS production and teratogenesis. These findings further our understanding of toxicant resistance by demonstrating that reduced response to coplanar PCBs and PAHs extends beyond resistance to CYP1A induction to resistance to the physiological and teratogenic effects of these toxicants, responses that undoubtedly contribute to the increased survival of killifish inhabiting contaminated sites. Environ. Toxicol. Chem. 2010;29:676–682. © 2009 SETAC
Modeling the response of passive samplers to varying ambient fluid concentrations of organic contaminants
Authors: Hawker Darryl W. 
Published: March 2010

Abstract
Passive samplers are an important and versatile adjunct to active sampling methods for air and water. The underlying theory is increasingly mature but is often based on the assumption of constant concentrations with time in the ambient fluid. This theoretical work details the passive sampler response to possible environmental situations in which ambient concentrations vary linearly with time, decrease exponentially with time, constitute a pulsed event, or oscillate regularly with time. The modeled shape of sampler response curve with time is characteristic and can be used to determine how fluid concentrations have changed with time. The sampler elimination rate constant is shown to be crucial in governing sampler response. Thus, by using performance reference compounds and under certain conditions, information from the sampler response can in theory be used to derive specific details of the temporal variation of the contaminant in the ambient fluid. For example, data captured by a passive sampler can be used to characterize a contamination pulse. This extends the versatility of passive samplers. Environ. Toxicol. Chem. 2010;29:591–596. © 2009 SETAC
Enantioselective induction of oxidative stress by permethrin in rat adrenal pheochromocytoma (PC12) cells
Authors: Hu Fen , Li Ling , Wang Cui , Zhang Quan , Zhang Xiaofeng , Zhao Meirong 
Published: March 2010

Abstract
Synthetic pyrethroid (SP) insecticides are chiral compounds with multiple asymmetric positions. Several recent studies have focused on the effect of enantioselectivity of SPs in acute aquatic toxicity, endocrine-disrupting activities, and immunotoxicity. However, the relevant molecular mechanisms are still unknown. The potential relationship between ecotoxicological effects and oxidative stress could contribute to SP-induced enantioselective cytotoxicity, but this requires further investigation. Therefore, this study was undertaken to evaluate the role of oxidative stress in enantiomer-specific permethrin (PM)-induced cytotoxicity in rat adrenal pheochromocytoma (PC12) cells. The study demonstrated that PM induced enantioselective oxidative stress and cytotoxicity. The reactive oxygen species (ROS) generation and lipid peroxidation production of malondialdehyde (MDA) were obviously increased, whereas the activity of antioxidant enzymes (superoxide dismutase [SOD] and catalase [CAT]) and glutathione (GSH) content had declined after exposure in 1R-trans-PM at a concentration of 30 mg/L. Meanwhile, the result of the cytotoxicity assay showed a clear, dose-dependent growth-inhibition effect of PM in an enantioselective manner. The most toxic effect on PC12 cells was shown by 1R-trans-PM and was approximately 1.6 times higher than that with 1S-cis-PM, which exhibited only a slightly toxic effect at a concentration of 20 mg/L. These results suggested that PM exhibited significant enantioselectivity in oxidative stress, which may be one of the initial events in PM-induced enantioselective cytotoxicity. The present study also improved understanding of enantiomer-specific, SP-induced cytotoxicity. The enantioselectivity should be taken into consideration when assessing ecological effects and development of new chiral pesticides. Environ. Toxicol. Chem. 2010;29:683–690. © 2009 SETAC
Complexes of glutathione with heavy metal ions as a new biochemical marker of aquatic environment pollution
Authors: Baloun Jiri , Adam Vojtech , Trnkova Libuse , Beklova Miroslava , Svobodova Zdenka , Zeman Ladislav , Kizek Rene 
Published: March 2010

Abstract
Reduced glutathione (GSH) plays a number of key roles in many biochemical pathways. This peptide is highly reactive and forms conjugates with other molecules via its sulfhydryl moiety. The interactions of the common heavy metal pollutant Cd(II) with GSH were determined by using the Brdicka reaction to evaluate whether this technique would be suitable as a biomarker. After GSH interaction with Cd(II) ions, two characteristic changes in the measured voltammogram were observed: Cat2 signal height decreased, and a new signal called P1 was found. The observed signal probably relates to the formation of a GSH–heavy metal ion complex adsorbed on the surface of the working electrode. When the interaction of GSH with cisplatin was studied, the same characteristic changes in the voltammogram were observed, which confirmed our hypothesis. Moreover, changes in the height of P1 and Cat2 signals with increasing time of GSH interaction with Cd(II) ions and/or cisplatin were also investigated. Cat2 peak height decreased proportionally with increasing time of interaction. This decrease can be explained by shielding of free sulfhydryl moiety by heavy metal ions, so it cannot catalyze the evolution of hydrogen from the supporting electrolyte. In addition, we found that, with increasing time of the interaction, the P1 signal was enhanced and shifted to more positive potentials for both Cd(II) ions and cisplatin. Environ. Toxicol. Chem. 2010;29:497–500. © 2009 SETAC
Heavy metals and metallothionein in vespertilionid bats foraging over aquatic habitats in the Czech Republic
Authors: Pikula Jiri , Zukal Jan , Adam Vojtech , Bandouchova Hana , Beklova Miroslava , Hajkova Pavlina , Horakova Jana , Kizek Rene , Valentikova Lucie 
Published: March 2010

Abstract
There has been growing interest in the study and conservation of bats throughout the world. Declines in their absolute numbers in recent decades are due, in part, to the fact that insectivorous bats may bioaccumulate toxic pollutants. The purpose of the present study was to quantify heavy metal concentrations in kidney, liver, and pectoral muscle samples in relation to metallothionein (MT) levels. In total, 106 bats belonging to 11 European species (i.e., Myotis myotis, Myotis daubentonii, Myotis brandtii, Myotis nattereri, Myotis emarginatus, Myotis mystacinus, Pipistrellus pipistrellus, Pipistrellus nathusii, Pipistrellus pygmaeus, Nyctalus noctulla, Eptesicus serotinus) were used for the study. The highest MT levels were found in Pipistrellus pipistrellus. High MT levels were also found in juvenile bats and aquatic-insect-foraging species. Cadmium was found only in the liver and kidney of Myotis myotis, except for a solitary finding in Pipistrellus pipistrellus. Myotis myotis juveniles had significantly higher liver and kidney Zn concentrations than adults. Interestingly, the liver Pb concentration was approximately two times higher in females than in males of Myotis myotis. The same gender difference was found for kidney Zn concentration in Pipistrellus pipistrellus. The present study confirms exposure of vespertilionid bats to toxic heavy metals (Pb, Cd) in the Czech Republic and provides data on the essential element Zn and the metal-binding protein MT in bats foraging over aquatic, aquatic and terrestrial, and terrestrial habitats. Environ. Toxicol. Chem. 2010;29:501–506. © 2009 SETAC
Passive sampling methods for monitoring endocrine disruptors in the Svratka and Svitava rivers in the Czech Republic
Authors: Grabic Roman , Jurcikova Jana , Tomsejova Sarka , Ocelka Tomas , Halirova Jarmila , Hypr Dusan , Kodes Vit 
Published: March 2010

Abstract
Endocrine-disrupting chemicals (EDC) are manmade or natural chemicals that have the ability to interfere with the endocrine system of animals. They have not been monitored systematically in the Czech Republic. The goal of the present study was the characterization of aquatic environmental pollution from the Brno (Czech Republic) city agglomeration focusing on EDC. Passive sampling devices, as well as semipermeable membrane devices (SPMD) and polar organic chemical integrative samplers (POCIS), were used for the pilot assessment of EDC. They were deployed for 21- to 28-d periods at nine locations in the Svratka and Svitava Rivers, Brno, Czech Republic, including at the inlet and outlet of Brno's wastewater treatment plant. The SPMDs were used to monitor nonpolar compounds such as polychlorinated biphenyls (PCBs), polynuclear aromatic hydrocarbons (PAHs), and organochlorinated pesticides (OCP). The POCIS were used to monitor polar compounds such as pesticides and their metabolites, perfluoro-organic compounds (PFOC), and pharmaceuticals. The passive samplers allowed very low detection limits for soluble (bioavailable) fractions of pollutants. The contribution of PAH, PCB, and HCB in sewage water to pollution of the Svratka River was low. The Brno wastewater treatment plant was identified as the main source of pharmaceuticals, triclosan, methyl triclosan, and some polar pesticides. Environ. Toxicol. Chem. 2010;29:550–555. © 2009 SETAC