bluuebunny/crossref_metadata_2025 huggingface dataset:
Toxicity of linear alkylbenzene sulfonates and nonylphenol in sludge-amended soil
Authors: Gejlsbjerg Bo , Klinge Charlotte , Samsøe-Petersen Lise , Madsen Torben
Published: March 2010

The application of sewage sludge to agricultural land brings several chemicals to the soil ecosystem. Linear alkylbenzene sulfonates (LAS) and nonylphenol (NP) are frequently found in sludge at relatively high concentrations. The toxic effects of LAS and NP to two soil invertebrates (Folsomia candida and Enchytraeus albidus) and five different microbial processes (aerobic respiration, nitrification, denitrification, anaerobic CH4 production, and anaerobic CO2 production) were investigated in sludge–soil mixtures. Median lethal concentrations (LC50 values) and median effective concentrations (EC50 values) were quite similar and calculated to be in the range of 1,143 to 1,437 and 71 to 437 mg/kg (dry wt) for LAS and NP, respectively. The EC50 values for nitrification and CH4 production were 431 and 277 mg/kg, respectively, for LAS and 343 and 754 mg/kg, respectively, for NP. Aerobic respiration and denitrification were not inhibited at the tested concentrations. The results show that NP was more toxic than LAS to both F. candida and E. albidus, whereas LAS was more toxic than NP to the anaerobic CH4 production. The safety margins between the lowest 10% effective concentration (EC10) and the estimated environmental concentration were a factor of 11 for LAS and 510 for NP when the concentrations of the contaminants corresponded to the current Danish cutoff values of 1,300 mg/kg for LAS and 30 mg/kg for NP.
Contaminant sensitivity of threatened and endangered fishes compared to standard surrogate species
Authors: Sappington Linda C , Mayer Foster L , Dwyer F. James , Buckler Denny R , Jones John R , Ellersieck Mark R
Published: March 2010

Standard environmental assessment procedures aredesigned to protectterrestrial and aquaticspecies. However, it is not known if endangered species are adequately protected by these procedures. At present, toxicological data obtained from studies with surrogate test fishes are assumed to be applicable to endangered fish species, but this assumption has not been validated. Static acute toxicity tests were used to compare the sensitivity of rainbow trout, fathead minnows, and sheepshead minnows to several federally listed fishes (Apache trout, Lahontan cutthroat trout, greenback cutthroat trout, bonytail chub, Colorado pikeminnow, razorback sucker, Leon Springs pupfish, and desert pupfish). Chemicals tested included carbaryl, copper, 4-nonylphenol, pentachlorophenol, and permethrin. Results indicated that the surrogates and listed species were of similar sensitivity. In two cases, a listed species had a 96-h LC50 (lethal concentration to 50% of the population) that was less than one half of its corresponding surrogate. In all other cases, differences between listed and surrogate species were less than twofold. A safety factor of two would provide a conservative estimate for listed cold-water, warm-water, and euryhaline fish species.
Joint acute toxicity of diazinon and ammonia to Ceriodaphnia dubia
Authors: Bailey Howard C , Elphick James R , Krassoi Rick , Lovell Adam
Published: March 2010

Dazinon is an organophosphorous pesticide widely found in municipal effluents as well as in agricultural and urban storm-water discharges. Ammonia is frequently also present in such effluents as a consequence of bacterial degradation of organic material. Because these two contaminants may occur concurrently, their relationship with respect to joint toxicity is of interest, particularly in regard to interpreting the results of effluent tests and subsequent toxicity identification evaluations (TIEs). In this particular case, we obtained an effluent sample that exhibited toxicity to Ceriodaphnia dubia. Toxicity identification evaluations manipulations suggested that ammonia (40 mg/L as total NH3) and diazinon (0.75 μg/L) both contributed to toxicity. As part of the Phase 3 confirmation studies, an independent investigation was conducted to evaluate the interactions between these two toxicants using static tests that incorporated a 48-h exposure period. Chemical concentrations were verified analytically. Mortalities were measured at 24-h intervals and joint toxicity calculated on the basis of toxic units (TUs) for each toxicant. The 48-h LC50 values (lethal concentrations for 50% of the population) for the individual chemicals averaged 0.36 μg/L and 1.11 mg/L for diazinon and un-ionized ammonia, respectively. Under the assumption of strict additivity, the sum of TUs contributed by each toxicant at the LC50 of the mixture should total unity. The TUs associated with the mixtures in laboratory water averaged 1.37 and 1.47, respectively, for 24- and 48-h exposure intervals. These results were similar to those obtained with the actual effluent sample and suggest that diazinon and ammonia exhibit less than additive toxicity when present together.
The effect of calcium and magnesium ratios on the toxicity of copper to five aquatic species in freshwater
Authors: Naddy Rami B. , Stubblefield William A. , May Jeffrey R. , Tucker Scott A. , Hockett J. Russell
Published: March 2010

While it is generally accepted that water hardness affects copper toxicity, the major ions that contribute to water hardness (calcium [Ca] and magnesium [Mg]) may affect copper toxicity differently. This is important because the Ca:Mg ratio in standard laboratory-reconstituted waters often differs from the ratio in natural surface waters. Copper toxicity was assessed for five different aquatic species: rainbow trout (RBT), fathead minnow (FHM), Ceriodaphnia dubia, Daphnia magna, and an amphipod (Gammarus sp.) under different Ca:Mg ratios (4:0, 3:1, 1:1, 1:3, and 1:4 mass basis) at a common hardness (180 mg/L as CaCO3) and alkalinity (120 mg/L as CaCO3). Copper toxicity increased at lower Ca:Mg ratios for RBT but increased at higher Ca:Mg ratios for D. magna. Fathead minnows (<24 h old) were more sensitive to copper in 1:1 Ca:Mg waters compared to 3:1 Ca:Mg waters. The toxicity of copper did not vary under different Ca:Mg ratios for Gammarus sp., C. dubia, and 28-d-old FHM. The effect of Ca:Mg ratios on copper toxicity changed for D. magna in softer water (90 mg/L as CaCO3) compared with hard water studies.
Effect of copper binding by suspended particulate matter on toxicity
Authors: Ma Huizhong , Kim Sang Don , Allen Herbert E. , Cha Daniel K.
Published: March 2010

The kinetics of Cu(II) interactions with Susquehanna River (mid-Atlantic, USA) particle suspensions using the copper ion selective electrode (Cu-ISE) method indicated that the concentration of Cu2+ in both the suspension and filtrate was kinetically controlled; the reaction of Cu(II) in the suspension was faster than that in the filtrate. Bioassay tests were performed in continuous flow-through bioassay systems to examine the effect of kinetics of Cu(II) interactions with suspended solids on the toxicity of Cu to Ceriodaphnia dubia. The toxicity curves were displaced to higher total Cu concentration as the reaction time increased, indicating that such interaction of Cu with solids was time dependent. Further, the toxicity curves overlapped for reaction times of 6 and 24 h, indicating that the reaction was relatively rapid and that equilibrium was achieved within 6 h. The survival of organisms was related to the free Cu2+ concentration but deviated from the result for bioassays in which dissolved organic matter (DOM) rather than particles reacted with the added Cu(II) to affect the free Cu2+ concentration. It may be interpreted that, besides the toxic effect of Cu2+, particles exert adverse influences on the organisms.
Sensitivity of an infaunal amphipod,Eohaustorius estuarius, to acute waterborne exposures of 4-nonylphenol: Evidence of a toxic hangover
Authors: Hecht Scott , Boese Bruce L.
Published: March 2010

Three independent trials were conducted using mortality and burial as endpoints. Amphipod mean lethal concentration to 50% (LC50) was 227 μg/L. One-hour burial as a sublethal endpoint increased the sensitivity of the toxicity test by 40%; however, most amphipods that survived exposure were able to recover within 24 to 48 h. This toxic hangover was dose-dependent.
A levy flight—random walk model for bioturbation
Authors: Reible Danny , Mohanty Sanat
Published: March 2010

Levy flights are employed in a lattice model of contaminant migration by bioturbation, the reworking of sediment by benthic organisms. The model couples burrowing, foraging, and conveyor-belt feeding with molecular diffusion. The model correctly predicts a square-root dependence on bioturbation rates over a wide range of biomass densities. The model is used to predict the effect of bioturbation on the redistribution of contaminants in laboratory microcosms containing pyrene-inoculated sediments and the tubificid oligochaete Limnodrilus hoffmeisteri. The model predicts the dynamic flux from the sediment and in-bed concentration profiles that are consistent with observations. The sensitivity of flux and concentration profiles to the specific mechanisms of bioturbation are explored with the model. The flux of pyrene to the overlying water was largely controlled by the simulated foraging activities.
Evaluation of western fence lizards (Sceloporus occidentals) and eastern fence lizards (Sceloporus undulatus) as laboratory reptile models for toxicological investigations
Authors: Talent Larry G. , Dumont James N. , Bantle John A. , Janz David M. , Talent Scott G.
Published: March 2010

A need is recognized for one or more laboratory reptile models for use in ecotoxicological studies and risk assessments. Maintenance of breeding populations of most reptile species under laboratory conditions is not practical because of their size and slow maturation rate. However, a number of species of spiny lizards (Sceloporus sp.) are small, mature quickly, and reproduce under laboratory conditions. We evaluated three populations of western fence lizards (S. occidentalis) and four populations of eastern fence lizards (S. undulatus) for their performance under laboratory conditions. We reared an F1 generation of each population and compared their performance relative to survival, growth, maturation rate, and reproductive output. A population from the San Joaquin Valley (CA, USA) performed especially well under laboratory conditions and is a good candidate for a laboratory model. We also examined the sensitivity of developing fence lizard embryos to an estrogenic chemical to determine if male secondary sex characteristics were affected. Microinjecting eggs with an estrogenic chemical (17α-ethinylestradiol) feminized males and prevented development of embryonic secondary sex characteristics. Therefore, embryonic fence lizards may be useful for studying the effects of endocrine-disrupting chemicals.
Determining the causes of impairments in the Little Scioto River, Ohio, USA: Part 2. Characterization of causes
Authors: Cormier Susan M. , Norton Susan B. , Suter Glenn W. , Altfater David , Counts Bernie
Published: March 2010

Two stream reaches in the Little Scioto River (OH, USA) were characterized for the causes of impairments measured at two locations. By inductive inference, six candidate causes were winnowed down to three and five candidate causes for each of the two stream reaches. Using a formal strength-of-evidence process, a single cause was determined. At the most upstream location, habitat alterations, including fine-textured substrates and low DO, were characterized as the probable causes for an increased percentage of anomalies of fish, a decreased percentage of mayflies, and an increased percentage of tolerant macroinvertebrates. An increase in the relative weight of fish was attributed to an artificially narrow, deepened channel. Approximately 2 km downstream, polycyclic aromatic hydrocarbon (PAH)-contaminated sediments were identified as the cause for both fish and macroinvertebrate impairments. Causal characterization using first elimination and then a strength-of-evidence approach narrowed and defined the causes of ecological impairment even in this situation, where many complex and interacting candidate causes existed. Applying a formal method highlighted types of data and associations that can strengthen and present a more convincing determination of the causes of impairment.
Integrating observational and experimental approaches to demonstrate causation in stream biomonitoring studies
Authors: Clements William H. , Carlisle Daren M. , Courtney Lisa A. , Harrahy Elisabeth A.
Published: March 2010

Routine biomonitoring of aquatic ecosystems generally is performed with the intent of demonstrating a causal relationship between stressors and responses. However, because it is impossible to eliminate other potential explanations for observed spatiotemporal correlation between stressors and responses, demonstrating causal relationships is highly tenuous in descriptive studies. In this research we show how results of descriptive and experimental approaches can be integrated to demonstrate a causal relationship between heavy metals and benthic community responses in a Rocky Mountain stream (CO, USA). By using a stressor identification process, we show that effects and exposure data collected from a contaminated site (Arkansas River, CO, USA) can be integrated with experimental data to support causal arguments. Analysis of the spatial co-occurrence of metals and benthic community responses in the Arkansas River provided support for the hypothesis that metals caused alterations in benthic community structure. Exposure pathways were quantified by measuring metal bioaccumulation in caddisflies (Trichoptera) collected upstream and downstream from metal inputs. A long-term (10-year) monitoring study showed that reductions in metal concentrations corresponded with improvements in benthic communities. These results were supported by microcosm and field experiments that quantified concentration-response relationships between heavy metals and benthic community composition. Consistency of these responses was demonstrated by comparing results to a spatially extensive survey of metal-polluted streams in Colorado. Our study demonstrates the power of integrating descriptive and experimental approaches for developing causal arguments in ecological assessments.
Increased toxicity to invertebrates associated with a mixture of atrazine and organophosphate insecticides
Authors: Anderson Troy D. , Lydy Michael J.
Published: March 2010

This study examined the joint toxicity of atrazine and three organophosphate (OP) insecticides (chlorpyrifos, methyl parathion, and diazinon) exposed to Hyalella azteca and Musca domestica. A factorial design was used to evaluate the toxicity of binary mixtures in which the lethal concentration/lethal dose (LC1/LD1, LC5/LD5, LC15/LD15, and LC50/LD50) of each OP was combined with atrazine concentrations of 0, 10, 40, 80, and 200 μg/L for H. azteca and 0, 200, and 2,000 ng/mg for M. domestica. Atrazine concentrations (>40 μg/L) in combination with each OP caused a significant increase in toxicity to H. azteca compared with the OPs dosed individually. Acetylcholinesterase (AChE) activity also was examined for the individual OPs with and without atrazine treatment. Atrazine in combination with each of the OPs resulted in a significant decrease in AChE activity compared with the OPs dosed individually. In addition, H. azteca that were pretreated with atrazine (>40 μg/L) were much more sensitive to the OP insecticides compared with H. azteca that were not pretreated with atrazine before being tested. Topical exposure to atrazine concentrations did not significantly increase OP toxicity to M. domestica. The results of this study indicate the potential for increased toxicity in organisms exposed to environmental mixtures.
Validation of pesticide root zone model 3.12: Employing uncertainty analysis
Authors: Carbone John P. , Havens Patrick L. , Warren-Hicks William
Published: March 2010

Computer models are being increasingly used to provide an efficient cost-effective means of evaluating the fate and behavior of chemicals in the environment. These models can be used in lieu of or in conjunction with field studies. Because of the increasing reliance on models for critical regulatory decision making, the need arose to assess the validity of regulatory models via an analysis of the correlation of model response estimates with measured data. In conjunction with the evaluation of the correlation of model response estimates and measured field data, a rigorous statistically based validation was also warranted. Because of the unique nature of the correlative exercise using modeled and measured data, standard statistical analyses, while informative, failed to encompass factors associated with the uncertainty of measured environmental fate data and potential model inputs. In an effort to evaluate this uncertainty, an initial sensitivity analysis was performed where key model input parameters for runoff and leaching simulations were identified. Once the sensitive input parameters were identified, a Monte Carlo-based preprocessor was developed whereby the sampling distributions of these parameters were used to propagate uncertainty in the input parameters into error in model predictions. Importantly, assumptions about parameter distributions for input into the Monte Carlo tool were made only after a formal detailed site-specific analysis of measured field data. Employing the functionality of the Crystal Ball® Pro development environment, the pesticide root zone model (PRZM) 3.12 was run iteratively for 500 trials, and model output was collated and analyzed. The model predictions were considered reasonably accurate for most regulatory requirements, and the model prediction error was considered acceptable.
A dynamic mass budget for toxaphene in North America
Authors: MacLeod Matthew , Woodfine David , Brimacombe Jenn , Toose Liisa , Mackay Don
Published: March 2010

A continental‐scale dynamic mass budget for toxaphene in North America is presented, based on available information on physicochemical properties, usage patterns, and reported environmental concentrations and using the Berkeley‐Trent North American mass balance contaminant fate model (BETR North America). The model describes contaminant fate in 24 ecological regions of North America, including advective transport between regions in the atmosphere, freshwater, and near‐shore coastal water. The dynamic mass budget accounts for environmental partitioning, transport, and degradation of the estimated 534 million kg of toxaphene that were used in North America as an insecticide and piscicide between 1945 and 2000. Satisfactory agreement exists between model results and current and historically reported concentrations of toxaphene in air, water, soil, and sediments throughout North America. An estimated 15 million kg of toxaphene are believed to remain in active circulation in the North American environment in the year 2000, with the majority in soils in the southern United States and Mexico, where historic usage was highest. Approximately 70% of total toxaphene deposition from the atmosphere to the Great Lakes is attributed to sources outside the Great Lakes Basin, and an estimated total of 3.9 million kg of toxaphene have been transported to this region from other parts of the continent. The toxaphene mass budget presented here is believed to be the first reported continental‐scalemultimedia mass budget for any contaminant.
Development and validation of an enzyme-linked immunosorbent assay to measure vitellogenin in the zebrafish (Danio rerio)
Authors: Brion François , Nilsen Bente M. , Eidem Janne K. , Goksøyr Anders , Porcher Jean Marc
Published: March 2010

In this study, an enzyme-linked immunosorbent assay (ELISA) was developed to quantify vitellogenin (Vtg) in zebrafish (Danio rerio). Zebrafish Vtg (zf-Vtg) was purified from whole-body homogenates of estradiol-exposed zebrafish, and polyclonal antibodies against zf-Vtg were raised. Using purified zf-Vtg as a standard and anti-zf-Vtg antibodies (DR-264), a competitive ELISA method was set up and validated. The working range of the assay is from 1 to 30 ng/ml (20–80% binding), and the detection limit is 0.4 ng/ml for purified zf-Vtg. In whole-body homogenates samples, the practical detection limit is higher than that for purified Vtg (40 ng/ml) due to matrix effect. The intra- and interassay variations were 4.7% and 14%, respectively, at 50% binding (n = 36). Its usefulness to detect changes in Vtg concentration in other cyprinid fish was also tested. In addition, the assay was used to assess Vtg induction in male zebrafish exposed to 17β-estradiol (E2). Exposure of male zebrafish to 0.1, 1, 10, and 100 μg/L of E2 for 7 d led to a Vtg induction from the lowest concentration. The results show the suitability of the developed ELISA to quantify Vtg inductions in zebrafish, the cross-reactivity of DR264 antibodies with commonly used cyprinids, and the potential of zf-Vtg induction as a sensitive biochemical endpoint that could be used to detect estrogenic properties of chemical substances.
Trace metal distribution in soluble organic matter from municipal solid waste compost determined by size-exclusion chromatography
Authors: Kaschl Arno , Römheld Volker , Chen Yona
Published: March 2010

Municipal solid waste (MSW) composts carry high amounts of trace metals and organic complexing agents that may influence metal bioavailability and mobility after application to soils. In order to assess the degree of organic complexation of trace metals in the solution phase of MSW compost and the relevance of organic ligand type, size exclusion chromatography (SEC) was applied to compost-extracted organic ligands. Adjustment of the elution conditions minimized the interaction with the gel matrix for compost humic substances and dissolved organic matter (DOM) fractions. The SEC was then used to separate the aqueous compost extract into samples with distinct differences in chemical constituents. The highest quantities of Cu, Zn, Ni, Mn, and Cd were found to coelute with the main peak of the SEC elution curve, which, as observed by Fourier-transformed infrared (FTIR) spectroscopy, also had the highest density of carboxyl groups. The ratio of aromatic to aliphatic structures was higher for eluates with low retention times, and cations such as Al, Cr, and Fe were preferably associated with these larger organic molecules. All trace metals in the compost solution phase were bound mostly to DOM rather than forming inorganic complexes.
Comparison of polycyclic aromatic hydrocarbon levels in mussels and oysters in France and the United States
Authors: Beliaeff Benoit , O'Connor Thomas P. , Munschy Catherine , Raffin Bernard , Claisse Didier
Published: March 2010

This paper compares data of 15 individual polycyclic aromatic hydrocarbon (PAH) concentrations from two monitoring programs: the French Réseau National d'Observation de la qualité du milieu marin (RNO) and the Mussel Watch project of the U.S. National Status and Trends (NST) program. Polycyclic aromatic hydrocarbon measurements in bivalve (mussels and oysters) are made from samples collected at 265 sites along the U.S. coastline and at 97 sites in the French coastal waters. Individual PAH patterns were found strikingly similar between the two countries with higher concentrations for high-molecular-weight (HMW) PAHs. Principal component analysis results for both RNO and NST show the variability to be dominated by just two components with HMW compounds contributing primarily to the first and low-molecular-weight (LMW) compounds to the second. This could imply a separation of petrogenic and pyrolytic sources with the latter being the more important in both nations accounting for the similarity in results.
Development of a fish reporter gene system for the assessment of estrogenic compounds and sewage treatment plant effluents
Authors: Ackermann Gabriele E. , Brombacher Eva , Fent Karl
Published: March 2010

This study reports on the development and application of a fish-specific estrogen-responsive reporter gene assay. The assay is based on the rainbow trout (Oncorhynchus mykiss) gonad cell line RTG-2 in which an acute estrogenic response is created by cotransfecting cultures with an expression vector containing rainbow trout estrogen receptor a complementary DNA (rtERα cDNA) in the presence of an estrogen-dependent reporter plasmid and an estrogen receptor (ER) agonist. In a further approach, RTG-2 cells were stably transfected with the rtERα cDNA expression vector, and clones responsive to 17β-estradiol (E2) were selected. The estrogenic activity of E2, 17α-ethinylestradiol, 4-nonylphenol, nonylphenoxy acetic acid, 4-tert-octylphenol, bisphenol A, o,p′-DDT, p,p′-DDT, o,p′-2,2-bis(chlorophenyl)-1,1-dichloroethylene (o,p′-DDE), p,p′-DDE, o,p′-2,2-bis(chlorophenyl)-1,1-di-chloroethane (o,p′-DDD), p,p′-DDD, and p,p′-2,2-bis(chlorophenyl)acetic acid (p,p′-DDA) was assessed at increasing concentrations. All compounds except o,p′-DDT, p,p′-DDE, and p,p′-DDA showed logistic dose-response curves, which allowed the calculation of lowest-observed-effect concentrations and the concentrations at which half-maximal reporter gene activities were reached. To check whether estrogen-responsive RTG-2 cells may be used to detect the estrogenic activity of environmental samples, an extract from a sewage treatment plant (STP) effluent was assessed and found to have estrogenic activity corresponding to the transcriptional activity elicited by 0.05 nM of E2. Dose-response curves of nonylphenol, octylphenol, bisphenol A, and o,p′-DDD revealed that the RTG-2 reporter gene assay is more sensitive for these compounds when compared to transfection systems recombinant for mammalian ERs. These differences may have an effect on the calculation of E2 equivalents when estrogenic mixtures of known constitution, or environmental samples, such as STP effluents, are assessed.
Responses of benthic invertebrates to combined toxicant and food input in floodplain lake sediments
Authors: De Haas Elske M. , Reuvers Bas , Moermond Caroline T. A. , Koelmans Albert A. , Kraak Michiel H. S.
Published: March 2010

Benthic communities in floodplain lake ecosystems are often exposed to varying levels of both food and toxicants. Inhibition through toxicants of sensitive species and stimulation through increased amounts of food of opportunistic species have been observed in separate studies. The aim of this study was therefore to assess the responses of benthic invertebrates to combined food and contamination input. Hence, seven floodplain lakes located along the River Waal, The Netherlands, with different levels of food (being either phytoplankton or macrophyte dominated) and toxicants were selected. The responses of the sensitive mayfly Ephoron virgo and the opportunistic midge Chironomus riparius to these sediments were assessed in 10-d growth bioassays with both species and a 28-d emergence experiment with C. riparius. A decrease in both survival and growth of E. virgo was observed with increasing contaminant levels. In contrast, C. riparius responded to the food quantity and quality in the sediments in spite of the toxicants present. Therefore, we conclude that the midge C. riparius is not a suitable test organism for the assessment of sediment toxicity. Alternatively, it proved to be an appropriate test organism to determine the nutritional value of sediments. The mayfly E. virgo turned out to be a much more appropriate test organism for sediment toxicity bioassays because it responds to the toxicant levels in the sediments rather than to the nutritional value. Our results demonstrate that the trophic state of an ecosystem (macrophyte or plankton dominated) influences the ecological risk of toxicants to benthic invertebrates in a species-specific way. It is concluded that not the toxicant load but the combination of food and contaminants determines the persistence of benthic invertebrates and therewith the benthic invertebrate composition in complexly polluted ecosystems.
Blood selenium concentrations and enzyme activities related to glutathione metabolism in wild emperor geese
Authors: Franson J. Christian , Hoffman David J. , Schmutz Joel A.
Published: March 2010

In 1998, we collected blood samples from 63 emperor geese (Chen canagica) on their breeding grounds on the Yukon-Kuskokwim Delta (YKD) in western Alaska, USA. We studied the relationship between selenium concentrations in whole blood and the activities of glutathione peroxidase and glutathione reductase in plasma. Experimental studies have shown that plasma activities of these enzymes are useful biomarkers of selenium-induced oxidative stress, but little information is available on their relationship to selenium in the blood of wild birds. Adult female emperor geese incubating their eggs in mid-June had a higher mean concentration of selenium in their blood and a greater activity of glutathione peroxidase in their plasma than adult geese or goslings that were sampled during the adult flight feather-molting period in late July and early August. Glutathione peroxidase activity was positively correlated with the concentration of selenium in the blood of emperor geese, and the rate of increase relative to selenium was greater in goslings than in adults. The activity of glutathione reductase was greatest in the plasma of goslings and was greater in molting adults than incubating females but was not significantly correlated with selenium in the blood of adults or goslings. Incubating female emperor geese had high selenium concentrations in their blood, accompanied by increased glutathione peroxidase activity consistent with early oxidative stress. These findings indicate that further study of the effects of selenium exposure, particularly on reproductive success, is warranted in this species.
Effects of ligand-bound silver on Ceriodaphnia dubia
Authors: Bielmyer Gretchen K. , Bell Russell A. , Klaine Stephen J.
Published: March 2010

In aqueous media, ionic silver concentrations are low and transport occurs in the colloidal phase. In the aquatic environment, silver forms 1:1 complexes with thiol-containing compounds such as cysteine and glutathione. In order to quantitatively characterize the risk associated with silver in aquatic ecosystems, the bioavailabilities and toxicities of silver cysteinate and silver glutathionate were characterized. Static renewal bioassays were conducted with Ceriodaphnia dubia to estimate chronic toxicity, using mortality and reproduction as endpoints. Silver nitrate was the most lethal compound, with a median lethal concentration (8-d LC50) of 0.32 μg Ag/L (95% confidence interval [CI] = 0.19–0.54). The 48-h LC50 for AgNO3 was 0.5 μg/L and did not change significantly through 8 d. The presence of food in the bioassay did not change the 48-h LC50 for AgNO3. Silver glutathionate (AgGSH) and silver cysteinate (AgCys) induced less mortality during the 8-d bioassay. Silver cysteinate appeared to have the greatest effect on fecundity, with a no-observable-effect concentration (NOEC) less than 0.001 μg/L. Silver nitrate and AgGSH had lowest-observable-effect concentration (LOEC) values (nominal concentrations) of 0.01 and 0.6 μg/L, respectively. Results indicate that the ligand-bound silver in these laboratory studies is bioavailable and impairs reproduction of C. dubia at low aqueous concentrations.
Effects of bisphenol a on the reproduction of Japanese medaka (Oryzias latipes)
Authors: Kang IK Joon , Yokota Hirofumi , Oshima Yuji , Tsuruda Yukinari , Oe Toshiaki , Imada Nobuyoshi , Tadokoro Hiroshi , Honjo Tsuneo
Published: March 2010

We elucidated the effects of bisphenol A (BPA) on the reproductive capacity (fecundity and fertility) and estrogenic response of adult Japanese medaka (Oryzias latipes) and studied the transgenerational effects (F1 generation growth and sex) of this agent on the F1 offspring. Eight mating pairs of medaka were exposed to BPA for three weeks at a measured concentration of 837, 1,720, or 3,120 μg/L. Throughout the exposure period, we observed no reduction of fecundity and fertility in any treatment group and no reduction in survival and growth or any imbalance of the sex ratio of the offspring. However, histologic examination revealed testis-ova in 13% of the males in the 837-μg/L treatment group, 86% of those in the 1,720-μg/L group, and 50% of those that received 3,120 μg BPA/L. In addition, concentrations of hepatic vitellogenin were increased significantly in males treated with BPA at 3,120 μg/L (p = 0.0148). These results suggest that BPA is a weakly estrogenic compound that has the potential to alter sexual development and induce vitellogenin in male medaka but that has no adverse effect on reproductive success.
Functional and morphological changes of lysosomes as prognostic biomarkers of toxic liver injury in a marine flatfish (Platichthys flesus (L.))
Authors: Köhler Angela , Wahl Ellen , Söffker Karin
Published: March 2010

Lysosomes are cell organelles in which macromolecules are recycled and that protect cells against toxins. In the present study, we apply histopathological and histochemical techniques in parallel with analytical chemistry of organochlorines and heavy metals in livers, with and without histopathological lesions, of the flatfish Plathichthys flesus (L.). The fish were caught along a pollution gradient on the German North Sea coast. We analyze critically whether changes in morphology and function of lysosomes, reflecting the onset and progression of toxipathic lesions in the liver of flounder, are appropriate for the rapid application in biological-effect monitoring programs such as BEEP (European Union Project in the 5th Framework Biological Effects of Environmental Pollutants in Marine Coastal Ecosystems). Livers collected from wild flounder were graded into four categories of lesions. Lysosomal stability was plotted against progressive lesions and contaminant levels in the same livers. Lysosomal membrane stability was already decreased at the onset of liver anomalies that are regarded as reversible. Reduced membrane stability also persisted in degenerative liver lesions and during carcinogenesis in liver parenchyma surrounding foci and tumors. Decreased lysosomal membrane stability coincided with increased size of lysosomes and increased lipid content during the progression toward degeneration. As predicted by the resistant-cell hypothesis, in proliferating cancer cells of adenomas and carcinomas, the highest values of membrane stability were detected. Concentrations of organochlorines such as hexachlorcyclohexane isomers, DDT metabolites, and polychlorinated biphenyls were correlated with reduced lysosomal membrane stability in noncancerous hepatocytes. On the basis of these findings, we recommend applying the lysosomal membrane stability test as an expertise-independent and rapid prognostic biomarker for toxically induced liver injury and carcinogenesis in monitoring programs.
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

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

Perfluorinated 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

Juvenile 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

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

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

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

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

Based 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