bluuebunny/crossref_metadata_2025_split huggingface dataset:
Performance of diffusion gradient in thin films to evaluate the toxic fraction of copper to Daphnia magna
Authors: Tusseau-Vuillemin Marie-Hélène , Gilbin Rodolphe , Bakkaus Estelle , Garric Jeanne 
Published: November 2004

Abstract
This study investigates the relevance of the diffusion gradient in thin films technique (DGT) to measure copper's induced lethality on Daphnia magna in natural water spiked with various organic ligands. Ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), and glycine were used as artificial organic ligands in controlled solutions of mineral water. With EDTA, DGT measurement makes it possible to predict the toxicity of the mixture because Cu-EDTA complexes are inert, whereas DGT is of no help in the case of NTA, because Cu-NTA complexes are fully labile. The Cu-glycine complexes appear as partly labile and toxic. Humic acids as well as fresh and aged algae extracts also were used as models for natural dissolved organic matters. All three of them form copper complexes that are not toxic to Daphnia magna and appear as partly labile with open-pored DGT. However, the use of restricted gels in DGT greatly reduces the contribution of labile complexes, at least for humic acids and aged algae copper complexes. The DGT with restrictive gels, therefore, appears to be a powerful tool for measuring bioavailable copper in natural water bodies, especially when the dissolved organic matter mostly is of humic origin. The DGTs potential ability to mimic the lability induced by the biological uptake also is discussed.
Methods to assess the amenability of petroleum hydrocarbons to bioremediation
Authors: Dobson Richard , Schroth Martin H. , Schuermann Andreas , Zeyer Josef 
Published: November 2004

Abstract
Bioremediation has achieved acceptance as a cost-effective technique for the remediation of soils and groundwater contaminated with petroleum hydrocarbons (PHC). A range of laboratory techniques to assess the biodegradability and bioavailability of PHCs are presented. Biodegradability and bioavailability are important determinants of the bioremediation performance of PHCs. Novel methods for the assessment of the bioavailability of PHC components are described. The techniques are demonstrated for a hydraulic fluid and a spindle oil from a contaminated site. Biodegradation is measured by oxygen consumption and carbon dioxide production. Bioavailability of the PHCs is estimated based on the PHC-water partitioning of tracer compounds and a novel analysis of gas chromatograms based on Raoult's law. The PHCs tested were only partially biodegradable (&lt; 25% in 78 d) due to the low solubility and likely recalcitrance of some of their components. The combination of techniques outlined is expected to be of use in assessing the likely bioremediation performance of PHCs for which published data are scarce or inadequate.
The effects of decanted sediments on embryogenesis in oysters (Crassostrea gigas)
Authors: Geffard Olivier , Budzinski Helene , His Edouard 
Published: November 2004

Abstract
Sediments act as sinks for contaminants of natural and anthropogenic origin, constituting a risk to the living organisms. In this study, sediments were collected from three sites on the coast of southwest France. The objective of this research was to determine the effects of sediments on embryonic development of bivalves and to identify precisely when the contaminants affect the embryos and induce them to develop in an abnormal way. The toxicity of decanted sediments and overlying waters were assessed using the oyster embryo bioassay. The physical characteristics and contaminant levels in the sediments were measured, including polycyclic aromatic hydrocarbon (PAH) and metal concentrations. Despite contaminant concentrations for PAH and metals only exceeding the effects range-low levels, all decanted sediments tested induced deleterious effects on the embryonic development of oysters, while no significant abnormalities were observed for overlying waters. The study results suggest that abnormal larvae mainly are caused by direct contact with contaminated sediments.
Concentrations of metals and trace elements in blood of spectacled and king eiders in northern Alaska, USA
Authors: Wilson Heather M. , Petersen Margaret R. , Troy Declan 
Published: November 2004

Abstract
In 1996, we measured concentrations of arsenic, barium, cadmium, lead, mercury, and selenium in blood of adult king (Somateria spectabilis) and spectacled (Somateria fischeri) eiders and duckling spectacled eiders from northern Alaska, USA. Concentrations of selenium exceeded background levels in all adults sampled and 9 of 12 ducklings. Mercury was detected in all adult spectacled eiders and 5 of 12 ducklings. Lead concentrations were above the clinical toxicity threshold in one duckling (0.64 ppm) and two adult female spectacled eiders (0.54 and 4.30 ppm). Concentrations of cadmium and mercury varied between species; barium, cadmium, mercury, and selenium varied between sexes. In female spectacled eiders, mercury concentrations increased during the breeding season and barium and selenium levels decreased through the breeding season. Selenium declined at 2.3 ± 0.9% per day and levels were lower in spectacled eiders arriving to the breeding grounds in northern Alaska than in western Alaska. The variation in selenium levels between breeding areas may be explained by differences in timing and routes of spring migration. Most trace elements for which we tested were not at levels currently considered toxic to marine birds. However, the presence of mercury and elevated lead in ducklings and adult female spectacled eiders suggests these metals are available on the breeding grounds.
Estrogenicity in bile of juvenile rainbow trout as measure of exposure and potential effects of endocrine disruptors
Authors: Allard Ann-Sofie , Gunnarsson Malin , Svenson Anders 
Published: November 2004

Abstract
Estrogenicity in the bile of juvenile rainbow trout exposed to effluents from municipal sewage treatment plants and various industries was assayed by using a recombinant yeast strain containing the human estrogen receptor α gene. Estrogenicity in bile also was measured after deconjugation of steroids to provide an estimate of the exposure and as an endpoint for potential effects on the organism. In unexposed fish or fish exposed for three weeks at control localities, 0.5 to 9 ng of estradiol equivalents (EEq) were found per gram of bile (ng EEq/g bile). Fish exposed for three weeks in cages placed in the receiving waters near outlets of municipal effluent had an average activity of 26 ng EEq/g bile. Fish exposed to undiluted sewage water in aquaria had a bile estrogenicity of 51 to 87,000 ng EEq/g bile. Unconjugated estrogens contributed only 8% or less to the estrogenicity in bile of fish exposed to municipal effluents. Municipal sewage effluents were more estrogenic than the industrial effluents that were investigated. Estrogenicity in bile was compared to that in extracts of wastewater by using the same receptor assay, and to vitellogenin induction in the plasma of the same fish. Bile estrogenicity proved to be a useful and sensitive (internal) measure of exposure and indicated its potential for the display of biological effects as a complement or replacement of more laborious assays.
Estrogenic and toxic effects of methoxychlor on zebrafish (Danio rerio)
Authors: Versonnen Bram J. , Roose Patrick , Monteyne Els M. , Janssen Colin R. 
Published: November 2004

Abstract
Although zebrafish (Danio rerio) have been suggested as a good candidate for screening potential endocrine disruptors, little information is available on the effects of weak estrogens on this species. We investigated the sensitivity of different life stages of zebrafish toward toxic and estrogenic properties of methoxychlor (MXC). Short-term tests with adults resulted in a sex-specific 96-h lethal concentration for 50% (LC50) of the test animals of 36 μg/L for males and 129 μg/L for females. To determine the estrogenic capacity of MXC, adult zebrafish were exposed to 0, 0.5, 5, and 50 μg MXC/L for 14 d. Induction of vitellogenin ([VTG] measured with protein electrophoresis and Western blot) in males was detected at 5 and 50 μg MXC/L. Females, however, did not exhibit higher blood VTG concentrations at the tested MXC concentrations. In a second series of experiments, juvenile zebrafish were exposed to 0, 0.05, 0.5, and 5 μg MXC/L for 33 d. Survival, length, weight, and condition of larvae were examined as indicators of toxic stress and the VTG content in whole body homogenates of juveniles was measured to determine xenoestrogenic effects. No effects of the tested concentrations of MXC were observed. Finally, the effect of MXC on zebrafish eggs, exposed to 0, 1, 10, and 32 μg MXC/L, was examined. Hatching and survival of hatched zebrafish were affected at 10 and 32 μg MXC/L. This study demonstrated that adult male zebrafish are sensitive toward the estrogenic effects of MXC. However, the use of VTG induction to detect effects of (xeno)estrogens in early life stages has to be further investigated, as low concentrations of VTG were detectable in exposed as well as unexposed juvenile fish.
Lethal and sublethal effects of low dissolved oxygen condition on two aquatic invertebrates, Chironomus tentans and Hyalella azteca
Authors: Irving Elaine C. , Liber Karsten , Culp Joseph M. 
Published: November 2004

Abstract
Low dissolved oxygen (DO) conditions occur frequently during sediment toxicity testing, with potentially adverse effects on test organisms. The present study addressed the current lack of good information regarding low DO thresholds for toxicity tests using two common test species, juvenile Hyalella azteca and Chironomus tentans larvae. Results indicated that H. azteca was less tolerant of hypoxia than C. tentans. The 10-d highest- and no-observed-effect concentrations (HOEC and NOEC, respectively) for H. azteca were 1.2 ± 0.1 and 2.9 ± 0.1 mg/L DO, respectively. The 10-d NOEC for C. tentans was 1.2 ± 0.1 mg/L DO, the lowest test concentration. Mortality was the predominant response of H. azteca to low DO exposure, with changes in growth and positioning behavior only evident at lethal DO concentrations. Although exposure to 1.2 ± 0.1 mg/L DO for 10 d did not affect C. tentans survival or growth, significant behavioral changes were evident at 2.0 ± 0.1 mg/L DO or less. Overall, the present results indicate that the North American guidelines for low DO thresholds during 10-d toxicity tests seem reasonable for juvenile H. azteca. However, the Environment Canada Guideline (3.4 mg/L DO at 23°C) may be considered to be conservative for 10-d toxicity testing with C. tentans if only short-term effects on survival and growth are considered.
Avoidance of copper contamination by field populations of Daphnia longispina
Authors: Lopes Isabel , Baird Donald J. , Ribeiro Rui 
Published: November 2004

Abstract
Almost all terrestrial and aquatic assays that are accepted as standardized, or that have been proposed, involve the exposure of confined organisms to toxicants. If avoidance (sensu evasion, displacement) of contaminants occurs in real situations, then bioassays involving forced exposure severely underestimate pernicious effects of contamination. Two main objectives were achieved in this study: To verify the occurrence of avoidance of copper by cladocerans; to determine the association between avoidance and other toxicity endpoints (lethality and feeding depression), and therefore, to ascertain if fully acclimated individuals from a reference field population exhibited a genetically determined avoidance markedly different from those belonging to a historically metal-stressed population. Twelve cloned lineages of the cladoceran Daphnia longispina, collected from two field populations, were selected according to their lethal sensitivity to copper and acclimated to controlled conditions for more than 30 generations. A 1.1-m test chamber with five compartments was built, allowing the establishment of a dissolved toxicant gradient and the free movement of individuals. In the absence of any toxicant, juveniles from each cloned lineage distributed themselves randomly along the test chamber and furthermore, no significant differences were observed between the two replicates, attesting the repeatability of this novel assay. All lineages showed significant avoidance to copper when exposed to a gradient from 3 to 87 μg/L. The most sensitive lineages to lethal levels of copper began avoiding this metal earlier than resistant ones. An intense association was observed between other endpoints and avoidance; furthermore, avoidance was determined to be much more sensitive than lethality. Therefore, avoidance assays should be recommended as a complementary tool in ecological risk assessments and effluent biomonitoring because such assays can provide cost-effective and ecologically relevant information.
Contaminant effects on the teleost fish thyroid
Authors: Brown Scott B. , Adams Bruce A. , Cyr Daniel G. , Eales J. Geoffrey 
Published: November 2004

Abstract
Numerous environmentally relevant chemicals, including polychlorinated hydrocarbons, polycyclic aromatic hydrocarbons, organochlorine pesticides, chlorinated paraffins, organophosphorous pesticides, carbamate pesticides, cyanide compounds, methyl bromide, phenols, ammonia, metals, acid loads, sex steroids, and pharmaceuticals, exert acute or chronic effects on the thyroid cascade in the approximately 40 teleost fish species tested to date. Thyroid endpoints, therefore, serve as biomarkers of exposure to environmental pollutants. However, the mechanisms underlying thyroid changes and their physiological consequences are poorly understood because the thyroid cascade may respond indirectly and it has considerable capacity to compensate for abuses that otherwise would disrupt thyroid hormone homeostasis. Indeed, a xenobiotic-induced change in fish thyroid function has yet to be conclusively causally linked to decreased fitness or survival. Other complications in interpretation arise from the diversity of test conditions employed and the often indiscriminate use of numerous thyroid endpoints. Future work should be directed toward standardizing test conditions and thyroid endpoints and investigating causal links between thyroid changes and fish growth, reproduction, and development. Development may be particularly susceptible to thyroid disruption, and thyroid endpoints appropriate for early life stages need to be applied.
Particulate arsenic and iron during anoxia in a eutrophic, urban lake
Authors: Senn David B. , Hemond Harold F. 
Published: November 2004

Abstract
The bioavailability and transport of particle-reactive pollutants are influenced by their partitioning between dissolved and particulate phases. We explored the importance of particle complexation to the arsenic cycle in an urban lake (Upper Mystic Lake, eastern MA, USA) that experiences arsenic remobilization from contaminated sediments during seasonal hypolimnetic anoxia. Particle size distributions were measured using a new in situ serial filtration system that excludes oxygen and filters at low flow rates to minimize filtration artifacts. Despite anoxia, the majority of remobilized As was present as As(V), and typically 85 to 95% of total As was particle complexed, with 25 to 50% found in the size fraction between 0.4 and 0.05 μm. Iron was distributed similarly among these size classes (&gt;95% of total Fe associated with particles larger than 0.05 μm, 30 to 50% between 0.4 μm and 0.05 μm), contrary to conventional expectation that the majority of Fe should be present as soluble Fe(II) in anoxic waters. By classical filtration (i.e., through a 0.4-μm filter), the colloidal fractions of both Fe and As would have been inaccurately classified as dissolved. Correlations between depth profiles of total As and particulate Fe as well as comparisons of measured arsenic sorption (i.e., total As &gt; 0.05 μm) against predictions by surface complexation modeling of As on amorphous Fe(III) oxides argue that arsenic sorbed on Fe(III) oxides was the major As species present in this lake's hypolimnion throughout several months of anoxia.
Environmental risk assessment of six human pharmaceuticals: Are the current environmental risk assessment procedures sufficient for the protection of the aquatic environment?
Authors: Ferrari Benoǐt , Mons Raphael , Vollat Bernard , Fraysse Benoǐt , Paxēaus Nicklas , Giudice Roberto Lo , Pollio Antonino , Garric Jeanne 
Published: November 2004

Abstract
In this study, exposure and ecotoxicity data of six human pharmaceuticals (carbamazepine, clofibric acid, diclofenac, ofloxacin, propranolol, and sulfamethoxazole) were collected, including our own experimental data and literature data. From this data collection, the two-tiered European draft guideline on the environmental risk assessment of human pharmaceuticals was tested. Measured environmental concentrations in effluents from France and in effluents and surface waters from Germany were compared to the predicted environmental concentrations (PECs) in both countries. In a similar manner, predicted no-effect concentrations (PNECs) derived from acute data and PNECs derived from chronic data were estimated for each pharmaceutical and corresponding PEC/PNEC ratios then were compared in both countries. Globally, results demonstrated that all environmental concentrations (predicted or measured) for each considered pharmaceutical exceeded the 10-ng/L cutoff value, which requires the implementation of the second-tier assessment based on ecotoxicity data. Moreover, the six pharmaceuticals showed a relatively limited acute toxicity, and carbamazepine and propranolol were inaccurately identified as having negligible risks under the current European draft procedure. Such results lead to discussion of the actual procedure on pharmaceuticals, especially on the need of appropriate ecotoxicity tests.
Dose-response relationships between herbicides with different modes of action and growth of Lemna paucicostata: An improved ecotoxicological method
Authors: Michel Albrecht , Johnson Robert D. , Duke Stephen O. , Scheffler Brian E. 
Published: November 2004

Abstract
Lemna species are widely used in ecotoxicological research to assess the phytotoxicity of environmental compounds. The purpose of the work described in this paper was to further refine the Lemna spp. bioassay, making it more robust and useful in comparing results between laboratories. A nondestructive image analysis method was used to measure growth as affected by herbicides during a time course. We tested 26 herbicides, with as many as 19 different modes of action, on leaf area growth of Lemna paucicostata to establish complete dose-response relationships. By using 3,5-dichlorophenol as a reference compound, different EC50 (concentration that inhibited growth by 50%) values of the herbicides can be compared. The EC50 values ranged from 0.003 μM for sulcotrione to 407 μM for asulam. Complete dose-response parameters were obtained that will better allow comparison of these results to those of other laboratories. These results should give useful information to anyone who works with Lemna species to address questions on herbicide residues in environmental compartments, screening of new herbicidal compounds, or the assessment of phytotoxic side effects of any compound.
Methylmercury uptake and distribution kinetics in sheepshead minnows, Cyprinodon variegatus, after exposure to CH3Hg-spiked food
Authors: Leaner Joy J. , Mason Robert P. 
Published: November 2004

Abstract
The distribution kinetics of methylmercury (CH3Hg[II]) was determined in sheepshead minnows (Cyprinodon variegatus) after a single dose of different CH3Hg(II)-spiked food to determine what factors influence the bioavailability, uptake, and redistribution of CH3Hg(II) to various organs of C. variegatus. The kinetics of CH3Hg(II) distribution was measured in the different organs during a period of 0.1 to 35 d after dosage. The CH3Hg(II) distribution kinetics in the different tissues was modeled using a simple multicompartmental pharmacokinetic model, which assumed that blood was the conduit linking the CH3Hg(II) exchange between the different organs. The CH3Hg(II) was taken up into the intestinal tissue within hours after feeding, followed by a slow release to the blood and the other organs of the body. Exchange between the blood and the visceral organs was relatively slow, with maximum CH3Hg(II) uptake in the liver and gill occurring at 1.5 d following dietary exposure. Subsequently, the majority of the CH3Hg(II) was channeled from the viscera to the rest of the body with a substantial lag time after feeding. However, the rate of transfer between tissues in the studies reported here were faster than those measured by others for larger fish.
Synergistic impacts of malathion and predatory stress on six species of North American tadpoles
Authors: Relyea Rick A. 
Published: November 2004

Abstract
The decline of many amphibian populations is associated with pesticides, but for most pesticides we know little about their toxicity to amphibians. Malathion is a classic example; it is sprayed over aquatic habitats to control mosquitoes that carry malaria and the West Nile virus, yet we know little about its effect on amphibians. I examined the survival of six species of tadpoles (wood frogs, Rana sylvatica; leopard frogs, R. pipiens; green frogs, R. clamitans; bullfrogs, R. catesbeiana; American toads, Bufo americanus; and gray tree frogs, Hyla versicolor) for 16 d in the presence or absence of predatory stress and six concentrations of malathion. Malathion was moderately toxic to all species of tadpoles (median lethal concentration [LC50] values, the concentration estimated to kill 50% of a test population, ranged from 1.25–5.9 mg/L). These values are within the range of values reported for the few amphibians that have been tested (0.2–42 mg/L). In one of the six species, malathion became twice as lethal when combined with predatory stress. Similar synergistic interactions have been found with the insecticide carbaryl, suggesting that the synergy may occur in many carbamate and organophosphate insecticides. While malathion has the potential to kill amphibians and its presence is correlated with habitats containing declining populations, its actual role in amphibian declines is uncertain given the relatively low concentration in aquatic habitats.
Water solubility and partitioning behavior of brominated phenols
Authors: Kuramochi Hidetoshi , Maeda Kouji , Kawamoto Katsuya 
Published: November 2004

Abstract
The water solubility (Sw) in the temperature range from 283 to 308 K and 1-octanol/water partition coefficient (Kow) for the nonionic form of brominated phenols (BPhs) of varying bromine content (4-bromophenol, 2,4-dibromophenol, 2,4,6-tribromophenol, and pentabromophenol) were measured by the generator-column or shake-flask method and by the high-performance liquid chromatography method, respectively. The temperature dependence of Sw, namely enthalpy of solution (ΔHsolution), was calculated using the van't Hoff Equation. To determine the activity coefficients in water (γw) of BPhs from the Sw data, enthalpy of fusion (ΔHfusion) and melting point (Tm) were measured by a differential scanning calorimetry method. The γw was used for evaluating data consistency as well as for predicting other physico-chemical properties, such as the Henry's law constant (Hw). The present work systematically reports, to our knowledge for the first time, the experimental values of Sw, Kow, ΔHsolution, ΔHfusion, Tm, and γw for BPhs with one to five bromines, and it discusses the effects of bromine content on these physico-chemical properties. Finally, the overall physico-chemical characteristics of BPhs are compared with those of polychlorinated phenols, polycyclic aromatic hydrocarbons, and brominated benzenes with the same solubility level as BPhs.