bluuebunny/crossref_metadata_2025 huggingface dataset:
Metabonomic assessment of toxicity of 4-fluoroaniline, 3,5-difluoroaniline and 2-fluoro-4-methylaniline to the earthworm Eisenia veneta (rosa): Identification of new endogenous biomarkers
Authors: Bundy Jacob G. , Lenz Eva M. , Bailey Nigel J. , Gavaghan Claire L. , Svendsen Claus , Spurgeon David , Hankard Peter K. , Osborn Daniel , Weeks Jason M. , Trauger Sunia A. , Speir Paul , Sanders Ian , Lindon John C , Nicholson Jeremy K. , Tang Huiru
Published: March 2010

High-resolution 1H nuclear magnetic resonance (NMR) spectroscopy can be used to produce a biochemical fingerprint of low-molecular-weight metabolites from complex biological mixtures such as tissue extracts and biofluids. Changes in such fingerprint profiles can be used to characterize the effects of toxic insult in in vivo systems. The technique is nonselective and requires little sample preparation or derivatization. In the present study, earthworms (Eisenia veneta) were exposed to three different model xenobiotics by a standard filter paper contact test, and toxicant-induced biochemical changes were then investigated by characterizing the changes in endogenous metabolites visible in 600-MHz 1H NMR spectra of tissue extracts. The NMR spectral intensities were converted to discrete numerical values and tabulated in order to provide data matrices suitable for multivariate analysis. Principal component analysis showed that changes had occurred in the biochemical profiles relative to the undosed controls. The 2-fluoro-4-methylaniline—treated worms showed a decrease in a resonance from a compound identified as 2-hexyl-5-ethyl-3-furansulfonate using a combination of high-performance liquid chromatography (HPLC)—Fourier transform mass spectrometry (IonSpec, Lake Forest, CA, USA) and 1H and 13C NMR spectroscopy. An increase in inosine monophosphate was also observed. The 4-fluoroaniline—treated worms showed a decrease in maltose concentrations, and 3,5-difluoroaniline exerted the same effect as 2-fluoro-4-methylaniline but to a lesser extent. These changes could potentially be used as novel biomarkers of xenobiotic toxicity and could be used to determine the mechanism of action of other toxic chemicals.
Effects analysis of time-varying or repeated exposures in aquatic ecological risk assessment of agrochemicals
Authors: Reinert Kevin H. , Giddings Jeffrey M. , Judd Laura
Published: March 2010

Exposure to agrochemicals in the aquatic environment often occurs as time-varying or repeated pulses. Time-varying exposures may occur due to runoff events and spray drift associated with precipitation and application events. Hydrologic dilution, dispersion, and degradation also produce pulsed exposures. Standard laboratory toxicity tests using constant exposure concentrations typically do not investigate the toxicity of time-varying or repeated exposures. Detoxification, elimination, and recovery may occur within organisms or populations during the periods between exposures. The difficulty of estimating effects of realistic time-varying exposures from measurements made under constant exposure conditions is often an important source of uncertainty in ecological risk assessment of pesticides. This article discusses the criteria and tools for deciding whether time-varying exposures are relevant in a particular risk assessment, approaches for laboratory toxicity testing with time-varying exposure, modeling approaches for addressing effects of time-varying exposure, deterministic and probabilistic ecological risk characterization of time-varying exposures and toxicity, and uncertainty analysis.
Photoredoction of the chloropropionic acid of careentrazone-ethyl in sodium sulfide crane flat meadow solutions
Authors: Ngim Kenley K. , Crosby Donald G.
Published: March 2010

The purpose of this study was to determine whether the conversion of carfentrazone-chloropropionic acid to carfentrazone-propionic acid in sunlit rice paddies is attributed to photoreduction. Model solutions (Na2S with quinoids) irradiated by laboratory ultraviolet light dechlorinated carfentrazone-chloropropionic acid (l.6–28.4% yield of carfentrazone-propionic acid), though Na2S alone was also reactive. Minor conversion (0–2.5%) occurred in the dark, along with dehydrochlorination to carfentrazone-cinnamic acid. Carfentrazone-propionic acid formed proportionally to the Na2S concentration (0–50.7% at 1.3–91 mM), whereas acidic pH inhibited reactivity. Photoreduction with Na2S was verified with 2-chloropropionic acid conversion to propionic acid (53.5%) and by minor 4-chlorophenoxyacetic acid dechlorination. Dissolved Na2S was the primary photoreductant, whereas reduced quinones degraded carfentrazone-chloropropionic acid by an alternate reaction. A survey of ambient rice field conditions indicates that carfentrazone-chloropropionic acid photoreduction is not directly attributed to H2S/HS− in this environment, though reduced quinones may be involved to an unknown extent.
Vapor phase transport of unexploded ordnance compounds through soils
Authors: Ravikrishna Raghunathan , Yost Sally L. , Price Cynthia B. , Valsaraj Kalliat T. , Brannon James M. , Miyares Paul H.
Published: March 2010

Unexploded ordnance(UXO) is a source of concern at several U.S. Department of Defense(DOD) sites. Localization of munitions and fate and transport of the explosive compounds from these munitions are a major issue of concern. A set of laboratory experiments were conducted in specially designed flux chambers to measure the evaporative flux of three explosive compounds (2,4-dinitrotoluene, 2,6-dinitrotoluene, and 1,3-dinitrobenzene) from three different soils. The effect of different soil moisture contents, the relative humidity of air contacting the soil surface, and soil temperature on the chemical fluxes were evaluated. A diffusion model was used to describe the chemical transport mechanism in the soil pore air. The soil-air partition constant was treated as a fit parameter in the model because of the uncertainty in the a priori estimation. The model predicts the qualitative trends of the experimental fluxes satisfactorily. Under extremely dry conditions, the flux decreased more rapidly than that predicted by the model. The fluxes from soils at 24°C were higher than those at 14°C, indicating a larger volatilization driving force at the higher temperature.
Prediction of uptake dynamics of persistent organic pollutants by bacteria and phytoplankton
Authors: Del Vento Sabino , Dachs Jordi
Published: March 2010

Phytoplankton and bacteria play an important role on the biogeochemical cycles of persistent organic pollutants (POPs). However, experimental data and quantitative knowledge of the kinetics of uptake and depuration of most POPs by bacteria and phytoplankton are scarce. In the present paper, a procedure to predict the sorption kinetics to bacteria and phytoplankton is developed. The prediction method is the combination of a mechanistic model for sorption and quantitative structure—activity relationships relating bioconcentration factors and membrane permeability to the chemical physical-chemical properties. The model consists of two compartments where the first compartment is the cellular surface and the second compartment is the cell biomass or matrix. Equations for estimating uptake and depuration rate constants into the matrix and adsorption and desorption rate constants onto the surface are obtained. These expressions depend on the physical-chemical properties of the chemical, the environmental temperature, the microorganism size, and species-specific quality of organic matter. While microorganism shape has a secondary influence on uptake dynamics, microorganism size and chemical hydrophobicity arise as the key factors controlling the kinetics of POP incorporation into bacteria and plankton. Uptake, depuration, adsorption, and desorption rate constants are reported for POPs such as polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), polychlorinated dioxins and furans (PCDD/Fs), and POPs of emerging concern, such as polybrominated diphenyl ethers (PBDEs). Finally, implications of uptake and depuration dynamics on the biogeochemical cycling of POPs are discussed.
Predicting chemical contaminants in freshwater sediments through the use of historical biochemical endpoints in resident fish species
Authors: Schlenk Daniel , Sapozhnikova Yelena , Baquirian Jean Paul , Mason Andrew
Published: March 2010

Previous studies in Bayou Bartholomew, Arkansas, USA, indicated significant relationships between the individual health of fish sampled from 13 sites and specific biochemical responses. Evaluation of several biochemical endpoints in 1994 indicated the bioavailable occurrence of either polychlorinated biphenyl (PCB) congeners or metals. To evaluate this possibility, in December 2000, sediments were collected at four sites on Bayou Bartholomew, where fish, collected in July 1994, had previously demonstrated the highest hepatic cytochrome P4501A (CYP1A) and heme oxygenase (HO) expression. Samples were analyzed for 89 PCB congeners, 18 organochlorine pesticides, and 25 metals. Total PCB concentrations ranged from 6.5 to 704 ng/g dry weight. Although several PCB congeners were observed, 81, 87, 99, 114, and 153 represented up to 33, 22, 29, 92, and 55% of the sum of PCBs from the four sites, respectively. Total organochlorine pesticide concentrations ranged from undetectable to 53.2 ng/g dry weight. Lindane, heptachlor, dachtal, dieldrin, hexachlorobenzene, dichlorodiphenyltrichloroethane (DDT), dichlorodiphenyl ethane (DDE), and dichlorodiphenyl dichloroethane (DDD) isomers were detected in most samples. Detected organophosphate pesticides included malathion, chlorpyrifos, and dimethoate. Both p,p′-DDE and p,p′-DDD were the most predominant of the pesticides measured (0.5–14.1 and 0.7–58.5 ng/g dry wt). All metal concentrations analyzed were below sediment quality guideline values. Metals exceeding national average concentrations were cobalt (2 of 4 [2/4] sites), copper (1/4), molybdenum (4/4), antimony (3/4), selenium (4/4), tin (4/4), and zinc (1/4). These results were consistent with PCBs being causative agents for the biochemical and adverse individual responses observed in fish sampled from this waterway.
Integrative assessment of benthic macroinvertebrate community impairment from metal-contaminated waters in tributaries of the upper Powell River, Virginia, USA
Authors: Schmidt Travis S. , Soucek David J. , Cherry Donald S.
Published: March 2010

Benthic macroinvertebrate communities of the North Fork Powell River (NFP), southwest Virginia, USA, appear to be impacted by aluminum (Al) and iron (Fe) from acid mine drainage (AMD) beyond the zone of pH depression. As part of a watershed restoration project, we used integrative techniques, including water column, sediment, and in situ toxicity tests; sediment and water column chemistry; and habitat assessments, to detect AMD impacts. An analysis of variance, least significant difference post hoc test, and Spearman correlations were used to test the sensitivity of these integrative techniques to detect various (acidic or neutralized) levels of AMD input and to determine the mode of impairment (metal-contaminated sediments or water) to the benthic macroinvertebrate community. Benthic macroinvertebrate indices were the most sensitive endpoint to AMD inputs and were significantly correlated (p ≤ 0.05) with water column metal concentrations in in situ and water column toxicity tests. Sediment chemistry and toxicity did not detect AMD impacts and were not significantly correlated with benthic macroinvertebrate indices. These results suggest that the primary mode of impairment to the benthic macroinvertebrate communities beyond the zone of pH depression were waterborne Al and Fe.
Oil effect in freshly spiked marine sediment on Vibrio fischeri, Corophium volutator, and Echinocardium cordatum
Authors: Brils Jos M. , Huwer Sherri L. , Kater Belinda J. , Schout Peter G. , Harmsen Joop , Delvigne Gerard A. L. , Scholten Martin C. Th.
Published: March 2010

The purpose of this study was to provide data to be used in The Netherlands for development of ecotoxicologically based quality criteria for oil-contaminated sediments and dredged material. In addition, the relation of toxicity to specific oil boiling-point fraction ranges was explored. Natural marine sediment, with a moisture, organic carbon, and silt content of approximately 80, 1.8, and 33% of the dry weight, respectively, was artificially spiked using a spiking method developed in this project. Aliquots of one part of the sediment were spiked to several concentrations of Gulf distillate marine grade A (DMA) gasoil (containing 64% C10–19) and aliquots of the other part to several concentrations of Gulf high viscosity grade 46 (HV46) hydraulic oil (containing 99.2% C19–40). Thus, for each individual oil type, a concentration series was created. Vibrio fischeri (endpoint: bioluminescence inhibition), Corophium volutator (endpoint:mortality), and Echinocardium cordatum (endpoint:mortality) were exposed to these spiked sediments for 10 min, 10 d and 14 d, respectively. Based on the test results, the effective concentration on 50% of the test animals was statistically estimated. For DMA gasoil and HV46 hydraulic oil, respectively, the effective concentrations were 43.7 and 2,682 mg/kg dry weight for V. fischeri, 100 and 9,138 mg/kg dry weight for C. volutator, 190, and 1064 mg/kg dry weight for E. cordatum. This study shows that the toxicity is strongly correlated with the lower boiling-point fractions and especially to those within the C10–C19 range.
Modeling explicitly and mechanistically median lethal concentration as a function of time for risk assessment
Authors: Bonnomet Vincent , Duboudin Cédric , Magaud Hélène , Thybaud Eric , Vindimian Eric , Beauzamy Bernard
Published: March 2010

A mechanistic model that explains how toxic effects depend on the duration of exposure has been developed. Derived from the dynamic energy budget (DEB)tox model, it expresses the hazard rate as a function of the toxic concentration in the organism. Using linear approximations in accordance with the general simplifications made in DEBtox, the concentration that induces x% of lethality (LCx) and in particular the lethal concentration 50% (LC50) are expressed explicitly as functions of time. Only three parameters are required: an asymptotic effect concentration, a time constant, and an effect velocity. More sophisticated (but still analytic) models are possible, describing more complex toxicity patterns such as an increase of sensitivity with time or, conversely, an adaptation. These models can be fitted to the common and widespread LC50 endpoints available from the literature for various aquatic species and chemicals. The interpretation of the values assigned to the parameters will help explain the toxicity processes and standardize toxicity values from different sources for comparisons.
Polychlorinated biphenyls associated with fine particles (PM2.5) in the urban environment of chile: Concentration levels, and sampling volatilization losses
Authors: Mandalakis Manolis , Stephanou Euripides G.
Published: March 2010

Polychlorinated biphenyls (PCBs) were measured in fine particles (PM2.5, particles smaller than 2.5 μm in diameter) collected in two urban areas of Chile, Santiago and Temuco, during August and October 1998. A diffusion denuder sampling system was used for the collection of 19 samples. The concentrations of total PCBs (47 congeners) ranged from 672 to 1,790 pg/m3 in the city of Temuco and from 1,159 to 2,750 pg/m3 in Santiago. These concentrations are moderately higher than those observed in other urban areas around the world. High amounts of PCBs may volatilize from fine particles during aerosols sampling using conventional high-volume samplers. Average volatilization losses, determined by the diffusion denuder system, varied between 54 and 97%, showing a strong dependence on partial pressure of individual PCB congeners and air temperature. Overall, our results suggest that measurements of PCBs in the particulate phase of the atmosphere, by using conventional high-volume samplers, might be significantly underestimated because of volatilization losses. The underestimation of PCB and other toxic semivolatile organic compound (SOC) levels associated with fine particles in the urban environment may have consequences to the estimation of health risk posed by inhalation.
Reconstructing source polybrominated diphenyl ether congener patterns from semipermeable membrane devices in the Fraser River, British Columbia, Canada: Comparison to commercial mixtures
Authors: Rayne Sierra , Ikonomou Michael G.
Published: March 2010

Semipermeable membrane devices (SPMDs) were placed in the Fraser River near Vancouver, British Columbia, Canada, between August 6 and September 30, 1996. This location is near a large urban and industrial region (population 2,000,000) and is expected to be representative of other large, modern cities. After exposure to the ambient water column, SPMD samples were analyzed for a suite of 36 polybrominated diphenyl ether (PBDE) congeners plus all homologue groups from mono- through hexabrominated. Observed congener patterns differed significantly from that of the commercial penta- and octa-BDE mixtures. A reconstruction approach was developed based on an aquatic transport model and utilizing published octanol-water partition coefficients, calculated SPMD uptake rates, and predicted water concentrations by using the EcoFate multimedia mass balance aquatic simulation model for the 13 major PBDE congeners. In combination, composite technical mixtures were created by combining commercial penta-BDE mixtures (Bromkal 70-5DE and Great Lakes Chemicals DE-71) with commercial octa-BDE mixtures (Bromkal 79-8DE and Great Lakes Chemicals DE-79) in their relative 2000 North American production volumes. The reconstructed SPMD patterns more closely approximated the composite technical mixtures and suggest that PBDEs in such an industrial region arise primarily from penta- and octa-BDE source mixtures.
Interaction modification among decomposers impairs ecosystem processes in lead-polluted soil
Authors: Salminen Janne , Korkama Tiina , Stroömmer Rauni
Published: March 2010

Environmental pollution by toxicants is generally believed to lead both to direct toxic effects and indirect effects via altered species interactions in a stressed community. We examined how contamination of a coniferous forest soil floor by lead (from an abandoned shooting range area) may alter trophic interactions and decomposition processes. We constructed laboratory microcosms containing microbial-based food webs with various trophic structures: microbes alone; microbes with microbivorous- detritivorous enchytraeid worms (Cognettia sphagnetorum, a potential keystone species of boreal forest soil); and microbes, worms, and predatory mites (Lysigamasus spp.) together. The direct toxic effect of lead and the effectiveness of the predators in preying upon the worms were studied in separate experiments. Polluted humic soil (acid-extractable lead concentration was 2,720 ± 349 mg/kg of dry soil [mean 6 standard error]) was toxic to enchytraeids, and predators effectively reduced worm populations. Positive density-dependent effects of worms on microbes and a trophic cascade from predatory mites to microbes, observed in the unpolluted humus, were not observed in the polluted humus, indicating pollution-induced interaction modification among organisms. Concomitantly, lead pollution altered the process of nutrient mineralization in the humic soil. However, causality and relative importance of direct toxicity and indirect effects of lead on the dynamics of the decomposer food web could not be pointed out. Examination of our results indicates that traditional food web models are incapable of predicting mechanisms that alter dynamics of pollutionstressed belowground food webs.
Polycyclic aromatic hydrocarbon bioaccumulation by meiobenthic copepods inhabiting a superfund site: Techniques for micromass body burden and total lipid analysis
Authors: Klosterhaus Susan L. , Lee Ferguson P. , Chandler G. Thomas
Published: March 2010

Microtechniques for polycyclic aromatic hydrocarbon (PAH) body burden and total lipid analysis were developed and applied to determine the first lipid-normalized bioaccumulation factors for a hydrophobic organic toxicant in a meiobenthic organism (0.063-0.500 mm) living in field-contaminated sediments. The total lipid microtechnique combines the standard Bligh-Dyer extraction method with a colorimetric quantification method for analysis of samples containing 1 to 50 μg lipid. The microtechnique for body burden analysis quantifies PAHs from tissue samples containing as little as 10 pg PAH. Fluoranthene, benz[a]anthracene, and benzo[a]pyrene biota-sediment accumulation factors (BSAFs) were determined for the meiobenthic copepod Microarthridion littorale living in an estuarine U.S. Environmental Protection Agency Superfund site. Gravid female, nongravid female, and male BSAFs were 0.82, 0.54, and 0.36, respectively, for fluoranthene; 0.50, 0.44, and 0.40, respectively, for benz[a]anthracene; and 0.09, 0.12, and 0.15, respectively, for benzo[a]pyrene. Comparison of nonlipid-normalized bioaccumulation factors (BAFs) to BSAFs indicates that M. littorale bioaccumulated PAHs on a gram lipid basis. The BSAFs declined consistently with increasing PAH log Kow for all copepod sex and reproductive stages. Sex- and stage-specific comparisons of BSAFs suggest that differences in lipid content and quality may lead to differences in BSAF values depending on PAH molecular weight and/or hydrophobicity.
Modeling cadmium dynamics in the guts and tissues of small mammals: Dose implications for predators
Authors: Toal Mark E. , Walker Lee A. , Shore Richard F.
Published: March 2010

Predators that consume contaminated small-mammal prey are exposed to pollutants present in both the prey tissues and the prey gut. However, the contribution of the prey gut and its contents to the contaminant intake of the predator is often ignored. This study developed a two-compartment model of the dynamics of Cd in a model prey species, the wood mouse (Apodemus sylvaticus). The results from the Cd dynamics model were used to calibrate a revised predator dose estimation methodology that accounted for contaminant uptake by a predator from both prey tissues and guts. The dose to the predator predicted by the revised methodology was compared to that predicted by conventional dose calculations, which account for contaminants in prey tissues only. The conventional approach underestimated Cd dose to a model predator by a factor of 1.2- to 10-fold, depending on prey age and predator behavior. Thus, accounting for the contaminant burden in the prey gut as well as in the tissues can markedly increase dose estimates to predators, and this is likely to be true for most low-bioavailability pollutants. This study has major implications for ecological risk assessment involving food chain transfer of low-bioavailability xenobiotics to predators.
Perpest model, a case-based reasoning approach to predict ecological risks of pesticides
Authors: Van den Brink Paul J. , Roelsma Jan , van Nes Egbert H. , Scheffer Marten , Brock Theo C. M.
Published: March 2010

The PERPEST model is a model that predicts the ecological risks of pesticides in freshwater ecosystems. This model simultaneously predicts the effects of a particular concentration of a pesticide on various (community) endpoints. In contrast to most effect models, PERPEST is based on empirical data extracted from the literature. This model is based on case-based reasoning, a technique that solves new problems (e.g., what is the effect of pesticide A?) by using past experience (e.g., published microcosm experiments). The database containing the past experience has been constructed by performing a review of freshwater model ecosystem studies. This review assessed the effects on various endpoints (e.g., community metabolism, phytoplankton, and macroinvertebrates) and classified them according to their magnitude and duration. The PERPEST model searches for analogous situations in the database, based on relevant (toxicity) characteristics of the compound. This allows the model to predict effects of pesticides for which no effects on a semifield scale have been published. The PERPEST model results in a prediction showing the probability of classes of effects (no, slight, or clear effects, plus an optional indication of recovery) on the various grouped endpoints. This paper discusses the scientific background of the model as well as its strengths, limitations, and possible applications.
Investigation of an onsite wastewater treatment system in sandy soil: Modeling the fate of surfactants
Authors: McAvoy Drew C. , Decarvalho Alvaro J. , Nielsen Allen M. , Cano Manuel L.
Published: March 2010

Field monitoring data for three common laundry detergent surfactants were used to test the applicability of a mathematical model that was developed as a screening-level tool for predicting the fate and transport of consumer product ingredients in septic systems. This model takes into account the simultaneous effects of sorption and biodegradation on the transport of chemicals through a septic system. Predicted groundwater concentrations of alcohol ethoxylate (AE) and alcohol ethoxy sulfate (AES) surfactants were in excellent agreement with measured values. This good agreement was to some extent due to the fact that the biodegradation rates of AE and AES do not vary significantly as a function of the degree of oxygenation of the soil. However, using laboratory-measured soil biodegradation rates for linear alkylbenzene sulfonate (LAS), the model underpredicted measured LAS concentrations in groundwater downgradient from the drainage field. This underprediction was due to the fact that the groundwater beneath the drainage field was anoxic during certain parts of the year and LAS is not degradable under this condition. Measured LAS concentrations were consistent with an assumed in situ soil biodegradation rate that was lower than the rate measured under fully oxygenated laboratory conditions. A limitation of the model is that only one soil biodegradation rate can be input for the saturated zone, even though biodegradation rates may vary seasonally or with distance from the drainage field. However, the model was appropriate and useful as a screening tool for the sorbable organic compounds studied. The applicability of the model to other classes of compounds should be assessed before broader application.
An avian bioassay for environmental estrogens: The growth response of zebra finch (Taeniopygia guttata) chick oviduct to oral estrogens
Authors: Millam James R. , Craig-Veit Christina B. , Batchelder Marianne E. , Viant Mark R. , Herbeck Tina M. , Woods Leslie W.
Published: March 2010

The rat uterotrophic assay is a recommended tier 1 screening assay for environmental estrogens, but no comparable assay exists for altricial birds. We orally dosed zebra finch chicks daily during their linear growth phase (days 5–11) with estradiol benzoate (EB), genistein, methoxychlor, or octylphenol, all dissolved or suspended in canola oil, or canola oil alone, as a vehicle control. On day 12, oviducts were removed, weighed and examined histologically. All doses of EB (0.1–1,000 nmol/g body wt), genistein at 100 nmol/g, and methoxychlor and octylphenol at 1,000 nmol/g, markedly increased oviduct weight, with the highest dose of EB inducing a 60-fold increase over controls. Oviducts were differentiated in a dose-depedent manner to the point of having tubular glands and a pseudostratified, ciliated epithelium at the higher doses of EB. Our earlier results show that EB at 100 and 1,000 nmol/g impairs reproductive performance of zebra finches. Thus, the zebra finch oviduct bioassay measures estrogenicity over a wide dose range and, for EB exposure, can predict impairment in adult reproductive performance. The responsiveness of chick oviducts to estrogen stimulation may serve as a useful marker of estrogen exposure in wild populations of songbirds.
Changes in toxicity and bioavailability of lead in contaminated soils to the earthworm Eisenia fetida (savigny 1826) after bone meal amendments to the soil
Authors: Davies Nicola A. , Hodson Mark E. , Black Stuart
Published: March 2010

The effect of bone meal (Ca5(PO4)3OH) amendments on lead (Pb) bioavailability to Eisenia fetida (Savigny 1826) was investigated. A standard uncontaminated soil was amended with Pb(NO3)2 solution to give Pb concentrations of 7,000 μg/g of soil. After one week, bone meal was added to one half of the soil in the ratio 1:20 bone meal:soil. Immediately after addition of the bone meal, survival times of E. fetida were 23 and 41 h in the bone meal-free and bone meal-amended soil, respectively. Twentyeight days after addition of the bone meal, survival times of Eisenia fetida were 67 h in the bone meal-free soil and more than 168 h in the bone meal-amended soil. In a second experiment, a standard Organisation for Economic Co-operation and Development reproduction toxicity test was carried out, but in addition to Pb(NO3)2 solution, bone meal was added to the soil in the ratio 1:20 bone meal:soil. The bone meal-free soil was left for five weeks before addition of E. fetida. In the bone meal-amended soil, bon emeal was added to the soil one week after addition of the Pb. The soil was left for a further four weeks before addition of Eisenia fetida. Calculated toxicities were significantly lower for the bone meal-amended soil than those calculated for the bone meal-free soil. Twenty-eight-day median lethal concentrations (LC50s; concentration that is statistically likely to kill 50% of the exposed test organism within a given time period ± 95% confidence intervals) of Pb were 4,379 ± 356 μg/g of soil for bone meal-free soil and 5,203 ± 401 μg/g of soil for bone meal-amended soil. Twenty-eight-day median effect concentrations (EC50s; concentration causing a reduction by 50% of a stated parameter) of Pb for weight change were 1,408 ± 198 μg/g of soil for bone meal-free soil and 3,334 ± 731 μg/g of soil for bone meal-amended soil and EC50s for cocoon production were 971 ± 633 μg/g of soil for bone meal-free soil and 1,814 ± 613 μg/g of soil for bone meal-amended soil. Significant mortalities occurred at Pb concentrations of 2,000 μg/g of soil in the bone meal-free soil and 5,000 μg/g of soil in the bone meal-amended soil. Earthworm Pb body load was lower in the bone meal-treated soil than in the bone meal-free soil up to a Pb concentration of 5,000 μg/g of soil. Earthworm Pb body load was approximately 100 μg/g of worm in surviving earthworms in both experiments when significant mortality occurred. Water and diethylenetriamine pentaacetic acid-extractable soil Pb showed good correlations with earthworm Pb body load. These extractions could be used as estimates for Pb bioavailability.
Copper toxicity thresholds for important restoration grass species of the western United States
Authors: W. Mark , Paschke  , Redente Edward F.
Published: March 2010

Copper toxicity thresholds for plant species that are used in restoration activities in western North America have not been established. As a result, ecological risk assessments must rely on toxicity thresholds established for agronomic species, which usually differ from those of species used in restoration. Thus, risk assessors have the potential for classifying sites as phytotoxic to perennial, nonagronomic species and calling for intensive remediation activities that may not be necessary. The objective of this study was to provide a better estimate of Cu toxicity thresholds for five grass species that are commonly used in restoration efforts in the western United States. We used a greenhouse screening study where seedlings of introduced redtop (Agrostis gigantea Roth.), the native species slender wheatgrass (Elymus trachycaulus [Link] Gould ex Shinners var. Pryor), tufted hairgrass (Deschampsia caespitosa [L.] Beauvois), big bluegrass (Poa secunda J. Presl var. Sherman), and basin wildrye (Leymus cinereus [Scribner&Merrill] A. Löve var. Magnar) and the agricultural species common wheat (Triticum aestivum L.) were grown in sand culture and exposed to supplemental concentrations of soluble Cu of 0 (control), 50, 100, 150, 200, 250, and 300 mg/L. We determined six measures of toxicity: the 60-d mean lethal concentration (LC50), 60-d mean effective concentration (EC50)-plant, 60-d EC50-shoot, 60-d EC50-root, phytotoxicity threshold (PT50)-shoot, and the PT50-root. Results suggest that these restoration grass species generally have higher Cu tolerance than agronomic species reported in the past. Of the species tested, redtop appeared to be especially tolerant of high levels of substrate and tissue Cu. Values of EC50-plant for restoration grasses were between 283 and 710 mg Cu/L compared to 120 mg Cu/L for common wheat. Measured PT50-shoot values were between 737 and 10,792 mg Cu/ L. These reported thresholds should be more useful for risk assessors than those currently used, which are based largely on agronomic crops.
A comparison of chelator-facilitated metal uptake by a halophyte and a glycophyte
Authors: Jordan Fional. L. , Robin-Abbott Molly , Maier Raina M. , Glenn Edward P.
Published: March 2010

Phytoextraction is the use of plants to remove contaminants, in particular metals, from soil via root uptake and translocation to the shoots. Efficient phytoextraction requires high-biomass plants with efficient translocating properties. Halophytes characteristically accumulate large quantities of salts in aboveground tissue material and can have high biomass production. It has been speculated that salt-tolerant plants may also be heavy metal tolerant and, further, may be able to accumulate metals. This study compared growth and metal uptake by a halophyte, Atriplex nummularia, and a common glycophyte, Zea mays, in a minetailing contaminated soil:mulch mixture. Two chelators, ethylenediaminetetraacetic acid (EDTA) and rhamnolipid, were used to facilitate plant metal uptake. Despite a lower growth rate (2% growth/d) in the contaminated soil, the halophyte accumulated roughly the same amount of metals as the glycophyte on a mass basis (30–40 mg/kg dry wt). Neither plant, however, hyperaccumulated any of the metals tested. When treated with EDTA, specific differences in patterns of metal uptake between the two plants emerged. The halophyte accumulated significantly more Cu (2X) and Pb (1X) in the shoots than the glycophyte, but root metal concentrations were generally higher for the glycophyte, indicating that the halophyte translocated more metal from the root to the shoot than the glycophyte. For example, Zn shoot-to-root ratios ranged from 1.4 to 2.1 for Atriplex and from 0.5 to 0.6 for Z. mays. The biodegradable chelator rhamnolipid was not effective at enhancing shoot metal concentrations, even though radiolabeled chelator was found in the shoot material of both plants. Our results suggest that halophytes, despite their slower growth rates, may have greater potential to selectively phytoextract metals from contaminated soils than glycophytes.
Transport behavior of 3,3′-dichlorobenzidine in a freshwater estuary
Authors: Nyman Marianne C. , McCord Kirby , Wood William L. , Blatchley Ernest R.
Published: March 2010

Like many hydrophobic organic compounds, 3,3′-dichlorobenzidine (DCB) partitions preferentially to (sediment) particles in lake systems. As such, the behavior of DCB in these systems is substantially affected by the movement of sediments. A field investigation of DCB distribution in sediments of Lake Macatawa (Holland, MI, USA) was initiated. The pattern of DCB distribution within the lake was found to display an oscillatory pattern that was consistent with a wind-driven mechanism of sediment transport. Numerical modeling of seiching behavior supported the hypothesized importance of this mechanism of sediment transport and redistribution. The dynamic behavior of sediment-associated DCB within Lake Macatawa seems to be strongly influenced by phenomena that are common to many freshwater estuaries. As such, the behavior of this system is expected to represent a reasonable model of the dynamic behavior of hydrophobic contaminants in other freshwater estuaries.
Toxicity evaluation of a commercial bioremediation agent mixed with crude oil
Authors: Bidwell Joseph R. , Cherry Donald S. , Merski A. Thomas
Published: March 2010

The toxicity and efficacy of a bacteria-based commercial bioremediation agent (CBA) was assessed through bioassays with juvenile inland silverside minnows, Menidia beryllina, and flask studies of oil degradation. Addition of the CBA to weathered Alaska, USA North Slope crude oil (ANS-521) prior to testing increased toxicity of the water-soluble fraction (WSF) of the oil in both chronic (growth) and acute (mortality) toxicity tests. Time-course toxicity assessment of the water-soluble fraction of the CBA/oil combination indicated increases in effect after 7 to 14 d of mixing that coincided with elevated concentrations of both alkanes and aromatics in the WSF. Under controlled laboratory conditions, the CBA significantly enhanced degradation of the oil compared with a treatment with nutrients alone. The alkane fraction was degraded by nearly 100% over a 42-d period while the aromatic fraction was decreased by 70%. While toxicity testing is not currently required to list bioremediation agents on the product schedule of the National Oil and Hazardous Substances Pollution Contingency Plan, the potential interaction between bioremediation agents and oil should be further investigated and listing requirements reassessed as necessary. Recommendations for future investigations of this issue include characterization of temporal trends in toxicity of CBA and oil mixtures, use of multiple test methods (battery testing) when evaluating toxicity, comparative evaluations of indigenous versus product-derived microorganisms in efficacy studies, and the use of a comparable oil between studies to facilitate comparison of efficacy and toxicity data for different products.
Assessment and characterization of polychlorinated biphenyls near a hazardous waste incinerator: Analysis of vegetation, snow, and sediments
Authors: Blais Jules M. , Froese Kenneth L. , Kimpe Lynda E. , Muir Derek C. G. , Backus Sean , Comba Michael , Schindler David W.
Published: March 2010

Samples of spruce needles, snowpack, and sediment were analyzed in the area around the Alberta Special Waste Treatment Centre (ASWTC) near Swan Hills, Canada, in 1997 and 1998, following a major accidental release of polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) in October 1996. The PCB concentrations in spruce needles and snow were mostly elevated to the east of the plant and contained congeners that were not present at upwind or distant sites. Several years of annual vegetation monitoring data indicated that PCB emissions increased prior to the reported accident. Within 3 km of the plant, there was a predominance of higher chlorinated congeners penta-, hexa-, hepta-, and octachlorobiphenyls in white spruce (Picea glauca) needles and snow. Polychlorinated biphenyl congener patterns varied seasonally in spruce needles, likely influenced by temperature effects on the volatilization and of particle-bound and vapor phase PCBs in the forest canopy. The similarity of deposition patterns in snow and needles in 1997 and 1998 suggested the PCBs in the surrounding area were derived by long-term fugitive releases of PCBs rather than an accidental release. In addition, hexachlorobenzene, a combustion byproduct of chlorinated organics in waste incinerators, was not measured at elevated concentrations in spruce needles or snow east of the facility and, when detected, was not correlated with PCB concentrations. A radiometrically dated sediment core from nearby Chrystina Lake (AB, Canada) showed a gradual increase in annual PCB flux during the early years of operation of the ASWTC, followed by a higher PCB flux in 1997, indicating that the lake may have been directly contaminated by the accidental release.
Studies of the environmental fate and effect of aircraft deicing fluids: Detection of 5-methyl-1H-benzotriazole in the fathead minnow (Pimephales promelas)
Authors: Cancilla Devon A. , Baird J. Christopher , Geis Steven W. , Corsi Steven R.
Published: March 2010

This paper presents the results of a number of field and laboratory studies to evaluate the environmental impact of aircraft deicing and anti-icing fluids (ADAFs) on aquatic systems. Both 5-methyl-1H-benzotriazole (5-MeBt) and 4-methyl-1H-benzotriazole (4-MeBt), known additives to ADAFs, were found in whole-tissue extracts from minnows placed downstream of an effluent outfall that receives ADAF contaminated runoff from General Mitchell International Airport (Milwaukee, WI, USA). Neither of these compounds was detected in tissues from minnows placed upstream from the airport. A toxicity assessment of water collected during the minnow exposure studies utilizing Hyalella azteca, Pimephales promelas, and Ceriodaphnia dubia showed greater toxicity in a secondary airport outfall containing ADAFs when compared to upstream non-ADAF-contaminated samples. In two 28-d static renewal tests using 5-MeBt laboratory-fortified waters, 5-MeBt was detected in whole-tissue extracts of minnows at all concentrations tested. In studies using laboratory water fortified with 5-MeBt, the median lethal concentration (LC50) of 5-MeBt for P. promelas was found to be 22.0 mg/L. The LC50 for C. dubia to 5-MeBt laboratory-fortified water was found to be 81.3 mg/L. The 25% inhibition concentration (IC25) of 5-MeBt for the green alga Selenastrum capricornutum was 23.2 mg/L, and the average median effective concentration (EC50) for Microtox® was 4.25 mg/L. The results of these field and lab studies indicate that additives, other than glycols, used in aircraft deicing fluids can be found in aquatic systems and may be of greater risk than previously believed.
Tributyltin causes masculinization in fish
Authors: Shimasaki Yohei , Kitano, Takeshi , Oshima Yuji , Inoue Suguru , Imada Nobuyoshi , Honjo Tsuneo
Published: March 2010

We examined the effect of tributyltin (TBT) on the sex differentiation process in genetically female Japanese flounder (Paralichthys olivaceus). The fish were fed an artificial diet containing tributyltin oxide (TBTO) at concentrations of 0.1 and 1.0 μg/g diet from 35 to 100 d after hatching, which includes the sex differentiation period. The ratio of sex-reversed males significantly increased to 25.7% of the flounder fed the 0.1 μg/g diet and to 31.1% of those fed the 1.0 μg/g diet compared with the control (2.2%). From morphological and histological examination of the fish in the TBT-treated groups, normal females had typical ovaries and sex-reversed males had typical testes. These results clearly demonstrated the masculinization of flounder exposed to TBTO. This is the first report of TBT inducing sex reversal in vertebrates.
Toxicity of triphenyltin and tributyltin to the freshwater mud snailPotamopyrgus antipodarumin a new sediment biotest
Authors: Duft Martina , Schulte-Oehlmann Ulrike , Tillmann Michaela , Markert Bernd , Oehlmann Jörg
Published: March 2010

The effects of two suspected endocrine-disrupting chemicals, the xeno-androgens triphenyltin (TPT) and tributyltin (TBT), were investigated in a new whole-sediment biotest with the freshwater mudsnail Potamopyrgus antipodarum (Gastropoda, Prosobranchia). Artificial sediments were spiked with seven concentrations, ranging from 10 to 500 μg nominal TPT-Sn/kg dry weight and TBT-Sn/kg dry weight, respectively. We analyzed the responses of the test species after two, four, and eight weeks exposure. For both compounds, P. antipodarum exhibited a sharp decline in the number of embryos sheltered in its brood pouch in a time- and concentration-dependent manner in comparison to the control sediment. The number of new, still unshelled embryos turned out to be the most sensitive parameter. The lowest-observed-effect concentration (LOEC) was equivalent to the lowest administered concentration (10 μg/kg of each test compound) for most parameters and thus no no-observed-effect concentration (NOEC) could be established. The calculation of effect concentrations (EC10) resulted in even lower values for both substances (EC10 after eight weeks for unshelled embryos: 0.03 μg TPT-Sn/kg, EC10 after four weeks for unshelled embryos: 0.98 μg TBT-Sn/kg). Our results indicate that P. antipodarum is highly sensitive to both endocrine disruptors TPT and TBT at environmentally relevant concentrations.
Developing transgenic arabidopsis plants to be metal-specific bioindicators
Authors: Krizek Beth A. , Prost Valerie , Joshi Ratan Mani , Stoming Terry , Glenn Travis C.
Published: March 2010

Deoxyribonucleic acid (DNA) microarrays provide a means to assess genome-wide expression patterns after exposure of an organism to different xenobiotics. Potential uses for this technology include identification of unknown toxicants, assessment of toxicity of new compounds, and characterization of the cellular mechanisms of toxicant action. Here we describe another use of DNA microarrays in toxicant-specific gene discovery. Combining results from two DNA microarray experiments, we have identified genes from the model plant Arabidopsis thaliana that are induced in response to one but not other heavy metals. The promoters of these genes should be useful in developing metal-specific transgenic biomonitors. To test this idea, we have fused the promoter of one of the newly identified Ni-inducible genes (AHB1) to the β-glucuronidase (GUS) reporter gene. Arabidopsis plants containing the AHB1::GUS transgene show reporter gene activity when they are grown on media containing Ni but not when grown on media containing Cd, Cu, Zn, or without added metals. Thus, this approach has resulted in the creation of a transgenic strain of Arabidopsis that can report on the presence and concentration of Ni in plant growth media. Such transgenic models can serve as cheap and efficient biomonitors of bioavailable heavy metal contamination in soils and sediments.
Impact of atrazine on aneuploidy in pacific oysters, Crassostrea gigas
Authors: Bouilly Karine , Leitão Alexandra , McCombie Helen , Lapègue Sylvie
Published: March 2010

Aneuploidy has previously been described and studied in the Pacific oyster, Crassostrea gigas, and has been shown to be negatively correlated with growth. The present study investigated the effect of atrazine on the level of aneuploidy in this species. Crassostrea gigas adults and juveniles were subjected to different concentrations of atrazine representing a peak value found in a polluted environment (46.5 nM) and a value 10 times higher (465 nM). Although atrazine did not show any effect on the oyster mortality, significant differences in aneuploidy level were observed between the different treatments (9% for the control, 16% for 46.5 nM and 20% for 465 nM atrazine). Moreover, the same levels of aneuploidy were observed at adult and juvenile stages. This is the first reported evidence for an environmental effect on aneuploidy in C. gigas. These results will be useful for the oyster aquaculture industry and management of resources. The lowest atrazine level in the current study represents realistic potential exposure, and the results suggest that studies should be made on other aquatic species at risk of exposure to atrazine in the wild. This widely used compound may be an important factor causing damage to genetic material.