bluuebunny/crossref_metadata_2025_split huggingface dataset:
Assessing the effects of modifying factors on pentachlorophenol toxicity to earthworms: Applications of body residues
Authors: Fitzgerald Dean G. , Warner Kathryn A. , Lanno Roman P. , Dixon D. George 
Published: March 2010

Abstract
This study examined the toxicokinetic relationship between critical body residues (CBRs) of pentachlorophenol (PCP) at lethality, soil PCP concentrations, and modifying factors of toxicity such as body size, species, temperature, and soil type during 28-d bioassays with earthworms. Eisenia fetida (0.2–0.4 g) were exposed to PCP at 15 and 24°C in artificial soil and at 24°C in Brookston clay. Lumbricus terrestris (3.3–4.6 g) and Eudrilus eugeniae (1.5–2.7 g) were exposed in artificial soil at 15 and 24°C, respectively. Soil PCP concentrations ranged from 0 to 6.75 mmol PCP/kg soil (dry weight), and body residues were measured by gas chromatography following cryoextraction of freeze-dried earthworms. Comparisons of toxicity were made using incipient lethal levels (ILLs) and CBRs at lethality. The equations estimated by nonlinear curve fitting of a one-compartment, first-order kinetics model provided a good fit to the observed data for all species, temperatures, and soil types at which tests were conducted. Incipient lethal levels for L. terrestris (0.72 mmol/kg soil) and E. eugeniae (0.63 mmol/kg soil) were similar and significantly higher than those for all E. fetida treatments. Incipient lethal levels for E. fetida exposed to PCP in artificial soil at 15 and 24°C were similar and lower than the ILL for E. fetida exposed to PCP in Brookston clay. The toxicity half-lives were similar for all E. fetida treatments but were higher than for the larger worms, L. terrestris and E. eugeniae, which were similar. Mean CBRs at lethality for E. fetida tested in artificial soil at 24°C ranged from 0.33 to 0.74 mmol/kg (wet weight) over the range of soil PCP exposure concentrations from 0.12 to 3.75 mmol PCP/kg. Mean CBRs for E. fetida exposed to PCP at 24°C in Brookston clay ranged from 0.51 to 1.59 mmol PCP/kg (wet weight) over the same range of soil PCP concentrations and were not significantly different. Critical body residues for E. fetida (15°C), L. terrestris, and E. eugeniae tested in artificial soil at 2.10 mmol PCP/kg ranged between 0.34 and 0.80 mmol PCP/kg. Residues in surviving worms were either similar to or lower than those in dead worms. Similar CBRs in three species of earthworms differing 10-fold in body size, and for E. fetida exposed to PCP concentrations ranging over more than two orders of magnitude in two different soil types, demonstrate that body residues can act to more effectively integrate the relationship between test organism, exposure, and mortality than soil toxicant concentrations alone.
Ecotoxicology of tropical marine ecosystems
Authors: Peters Esther C , Gassman Nancy J , Firman Julie C , Richmond Robert H , Power Elizabeth A 
Published: March 2010

Abstract
The negative effects of chemical contaminants on tropical marine ecosystems are of increasing concern as human populations expand adjacent to these communities. Watershed streams and ground water carry a variety of chemicals from agricultural, industrial, and domestic activities, while winds and currents transport pollutants from atmospheric and oceanic sources to these coastal ecosystems. The implications of the limited information available on impacts of chemical stressors on mangrove forests, seagrass meadows, and coral reefs are discussed in the context of ecosystem management and ecological risk assessment. Three classes of pollutants have received attention: heavy metals, petroleum, and synthetic organics such as herbicides and pesticides. Heavy metals have been detected in all three ecosystems, causing physiological stress, reduced reproductive success, and outright mortality in associated invertebrates and fishes. Oil spills have been responsible for the destruction of entire coastal shallow-water communities, with recovery requiring years. Herbicides are particularly detrimental to mangroves and seagrasses and adversely affect the animal-algal symbioses in corals. Pesticides interfere with chemical cues responsible for key biological processes, including reproduction and recruitment of a variety of organisms. Information is lacking with regard to long-term recovery, indicator species, and biomarkers for tropical communities. Critical areas that are beginning to be addressed include the development of appropriate benchmarks for risk assessment, baseline monitoring criteria, and effective management strategies to protect tropical marine ecosystems in the face of mounting anthropogenic disturbance.
Marine heterotrophic bacteria as indicators in the quality assessment of coastal waters: Introducing the “apparent bacterial concentration” approach
Authors: Sbrilli Giancarlo , Cruscanti Marco , Bucci Mario , Gaggi Carlo , Bacci Eros 
Published: March 2010

Abstract
A simplified fingerprint, obtained by counting the colonies of luminescent and nonluminescent bacteria developing on filters plated on a solid culture medium, was applied to obtain an indication of coastal water quality. Results from a reference area and three polluted sites (essentially by urban sewage) and their variations during the year are reported. A tentative characterization of the “clean” and polluted sites is made.
Evaluation of temporal and age-related trends of chemically and biologically generated 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents in lake Ontario lake trout, 1977 to 1993
Authors: Huestis Susan Y , Servos Mark R , Whittle D Michael , van den Heuvel Michael , Dixon D George 
Published: March 2010

Abstract
Levels of selected non-, mono-, and di-ortho-substituted polychlorinated biphenyl (PCB) congeners, polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs) were determined in 4-year-old lake trout from the eastern basin of Lake Ontario, collected from 1977 to 1993. Results confirm that overall levels of contaminants have decreased steadily in lake trout since 1977, and that coplanar PCB levels do not appear to be increasing over time in relation to levels of other PCBs. Contaminant levels in lake trout from 3 to 9 years old, collected in 1988 from the western end of Lake Ontario, show the body burden of contaminants increases with age. Relative levels of coplanar PCBs to other PCBs for the age study samples showed no change, except for PCB 77, which exhibited a slight decrease in relation to total PCB levels. Toxic equivalents (TEQs) were calculated from fish contaminant concentrations measured for the time study using toxic equivalence factors (TEFs) from both mammalian and teleost studies. The relative contributions of PCBs, PCDDs, and PCDFs to total TEQs were examined. When TEFs used for risk assessment are applied to temporal trend data, 15 to 20% of the total TEQs were due to mono-ortho-substituted PCBs; 40 to 50% to non-ortho coplanar PCBs; and 20 to 30% to 2,3,7,8-substituted PCDD and PCDFs. The TEQs determined from lake trout extracts by an H4IIE cell bioassay technique are compared to those determined by chemical analyses, using a variety of TEFs.
Effects of the antibiotic baytril (enrofloxacin) on pcb-initiated induction of cytochrome P4501A mRNA in sexually mature Atlantic tomcod (Microgadus tomcod)
Authors: Williams Jim , Courtenay Simon C , Wirgin Issac I 
Published: March 2010

Abstract
We used a factorial experimental design to determine whether the antimicrobial Baytril (enrofloxacin) had an effect on induction of cytochrome P4501A (CYP1A) mRNA in Atlantic tomcod. Fish were injected with corn oil, Baytril and corn oil, Baytril and 3,3′,4,4′-tetrachlorobiphenyl (PCB) dissolved in corn oil, or just PCB in corn oil. Analysis of gene induction in both sexes considered together showed significant induction by PCB treatment and a significant effect of sex (males higher than females). Because the experiment was carried out just before spawning, our results provide additional evidence for pretranslational suppression of CYP1A induction in spawning females. Separate analysis of the sexes showed that in both males and females, PCB had a significant effect on induction. However, in analyzing the males we also observed significant induction by Baytril alone. In addition, the BaytrilPCB combination resulted in the highest induction in any group. These findings demonstrate the potential for confounding results due to exposure of sampled fish to antibiotics, either in a laboratory or field situation.
Effects of the insecticide Dursban®4e (active ingredient chlorpyrifos) in outdoor experimental ditches: Responses of ecosystem metabolism
Authors: Kersting Kees , van den Brink Paul J 
Published: March 2010

AbstractExperimental ditches were teated with Dursban®4E at nominal concentrations of 0, 0.1, 0.9, 6, and 44 μg/L of the active ingredient chlorpyrifos. Continuous oxygen, pH, and temperature measurements were made to determine the ecosystem metabolism. In addition, alkalinity and conductivity were determined weekly. Oxygen concentrations and pH were elevated at the highest treatment level. The “dissolved oxygen-pH-alkalinity-conductivity syndrome” was analyzed with the multivariate ordination technique “redundancy analysis” and indicated a temporary effect of chlorpyrifos. Whole-system gross primary production and oxygen consumption were both lowered in relation to the treatment, with oxygen consumption showing the most prominent decrease. These effects are explained as a decrease in decomposition after the arthropods are killed. The effect of chlorpyrifos on the ecosystem metabolism is slight. The influence of the state of the ecosystem on the response of ecosystem functions to insecticide treatment is also discussed.
Susceptibility of early life stages of Xenopus laevis to cadmium
Authors: Herkovits Jorge , Cardellini Pietro , Pavanati Cristina , Perez-Coll Cristina S 
Published: March 2010

Abstract
The susceptibility of Xenopus laevis to cadmium during different stages of development was evaluated by exposing embryos to cadmium concentrations ranging from 0.1 to 10 mg Cd2+/L for 24, 48, and 72 h and assessing lethality and malformations. Susceptibility increased from the two blastomeres stage (stage 2) to stage 40, in which the 24-h LC100 was 1.13 mg Cd2+/L, and resistence increased from this stage onward. Malformations occurred at all developmental stages evaluated, the most common being reduced size, incurvated axis, underdeveloped or abnormally developed fin, microcephaly, and microphtalmy. Scanning electron microscopy revealed changes in the ectodermal surface ranging from slightly vaulted cells to a severe reduction in the number of ciliated cells as the concentration of cadmium increased. The intraspecific variation evaluated in embryos (from four sets of parents) at seven developmental stages, expressed as the coefficient of variation of the LC100, ranged from 10 to 112% and reflects the capacity of Xenopus laevis to adapt to changing environmental conditions at different embryonic stages.
Bioaccumulation of cesium-137 in yellow bullhead catfish (Ameiurus natalis) inhabiting an abandoned nuclear reactor reservoir
Authors: McCreedy Clark D , Jagoe Charles H , Glickman Lawrence T , Brisbin I Lehr 
Published: March 2010

Abstract
Bioaccumulation of 137Cs was investigated in yellow bullhead catfish (Ameiurus natalis) inhabiting an abandoned reactor reservoir, Pond B, Savannah River Site, Barnwell Co., South Carolina. We collected fish by trap-netting, and determined ages from pectoral spines. Muscle and other tissues were assayed for 137Cs by NaI-scintillation. Muscle 137Cs was unrelated to sex (p = 0.859) or mass of fish (p = 0.224), but was related to age (p = 0.036). Examination of least-squares means suggested that 137Cs in muscle increased up to about age 3, but did not increase with greater age (means for 1, 2, 3, 4, 5, and 6 year olds were 2,630, 3,011, 3,513, 3,417, 3,599, and 3,339 Bq/kg, respectively). A modified Richards model showed equilibrium 137Cs concentration in muscle (3,625 Bq/kg) was acquired in approximately 2.4 years. Growth differed between sexes (p &lt; 0.001), and the time to asymptotic body mass was longer than the time to attain equilibrium 137Cs concentration. Males attained an asymptotic mass of 577 g in approximately 6.3 years; females attained an asymptotic mass of 438 g in approximately 5.9 years. The cumulative 137Cs burden of the population was 4.9 × 106 Bq, representing &lt;0.001% of the 137Cs inventory of the reservoir. Concentration of 137Cs varied among tissues (p &lt; 0.001), with gill and muscle the lowest and highest (634 and 3,712 Bq/kg, respectively). Concentration of 137Cs in ovaries declined with increasing ovary mass (p = 0.001; r2 = 0.60). Until equilibrium is attained in these fish, 137Cs concentration is directly related to increasing age rather than size.
A comparison of the toxicity and metabolism of phenol and chlorinated phenols by Lemna gibba, with special reference to 2,4,5-trichlorophenol
Authors: Sharma Hari A , Barber John T , Ensley Harry E , Polito Michael A 
Published: March 2010

Abstract
The toxicity of a series of chlorinated phenols, from phenol to pentachlorophenol, was determined using frond reproduction in aseptically grown Lemna gibba. The toxicities of the phenols tended to increase as the number of chlorine substituents on the phenol ring increased. The plants metabolized each of the phenols in the same manner producing metabolites that were more polar than their parent compounds. The metabolite for 2,4,5-trichlorophenol was isolated and identified by nuclear magnetic resonance spectroscopy and chemical ionization mass spectroscopy. The structural identity was confirmed by comparison with synthetic material as 2,4,5-trichlorophenyl-β-D-glucopyranoside. These results, together with previously published results, suggest that conjugation with D-glucose is a stereotypic response of duckweed to challenge by phenol and chlorinated phenols.
A screening method for ranking and scoring chemicals by potential human health and environmental impacts
Authors: Swanson Mary B , Davis Gary A , Kincaid Lori E , Schultz Terry W , Bartmess John E , Jones Sheila L , George Emma Lou 
Published: March 2010

Abstract
Potential impacts of chemical releases are often evaluated by regulators, industry, and others to set regulatory action priorities, to make business decisions, and to target pollution prevention efforts. A chemical ranking and scoring method entitled “Chemical Hazard Evaluation for Management Strategies” (CHEMS-1) has been developed as a screening tool to provide a relative assessment of chemical hazards to human health and the environment. The purpose of this method is to place chemical release data into perspective by evaluating both the toxic effects of chemicals and the potential exposure to those chemicals. This is done by combining measures of chemical toxicity pertaining to both human health and the environment with chemical release amounts and information on environmental persistence and bioaccumulation. The CHEMS-1 was initially developed to select priority chemicals for assessing safer substitutes for major product and process uses, where chemicals were selected from Toxics Release Inventory (TRI) data and annual pesticide usage data. A two-tiered approach was adopted with CHEMS-1 presented here representing the first, or screening-level, tier.
Retention of imazaquin in soil
Authors: Regitano Jussara B , Bischoff Marianne , Lee Linda S , Reichert Jose Miguel , Turco Ronald F 
Published: March 2010

Abstract
The molecular complexity of imazaquin and presence of ionizable functional groups limits the ability to predict sorption behavior from single soil parameters such as organic carbon content. Partition coefficients (Kp) for both neutral and anionic forms of imazaquin as well as the effects of solution ionic strength and composition were investigated to more adequately describe sorption of imazaquin in soil. Soils representing a range of characteristics were evaluated, including soils with permanent negative or variable surface charge. Imazaquin retention resulted from combined sorption for the neutral (Kocn, 1,110 ± 80 L/kg) and anionic (Koc,a, 38 ± 20 L/kg) forms. Imazaquin sorption was best correlated to soil organic carbon content and soil-solution pH. However, results indicated that positively charged Fe2+ and Al3+ oxyhydroxides contribute to sorption of the organic anion; thus mineral surfaces contributed to sorption in soils with low organic carbon content. The effects of electrolyte matrices on imazaquin sorption were accounted for by concomitant changes in pH. However, enhanced imazaquin sorption was observed with increasing ionic strength for soils where pH-induced changes in speciation were negligible, indicating the role of mechanisms other than weak hydrophobic interactions. Addition of H2 PO −4 significantly decreased imazaquin sorption, especially in weathered soils.
Isolation and characterization of Microtox®-active components from aircraft de-icing/anti-icing fluids
Authors: Cancilla Devon A , Holtkamp Anke , Matassa Luca , Fang Xingchun 
Published: March 2010

AbstractThe goal of this project was to isolate and identify individual components from aircraft de-icing/anti-icing fluids (ADAs) through a toxicity-based bioassay analysis. A Microtox® bioassay fractionation scheme was used to isolate a number of active fractions from ADAFs. Active fractions were identified using multiple spectral techniques, including nuclear magnetic resonance, gas chromatography–mass spectrometry, liquid chromatography–mass spectrometry, and ultraviolet characterization. The primary Microtox-active fraction was shown to be a mixture of benzotriazole and tolyltriazoles, which are used as corrosion inhibitors in ADAF formulations. The identity of the compounds was confirmed through spectral and Microtox-toxicity analysis and comparison of commercially available standards.
Potential toxicity and aerobic biodegradability of sodium silicate chemical grout leachate
Authors: Malone J Michael , St. John Todd W , Barlaz Morton A , Borden Roy H 
Published: March 2010

Abstract
Large quantities of organic reagents are used in sodium silicate grouts for the stabilization of granular soils prior to construction projects. However, the fate and effects of these reagents in the subsurface are unknown. In this study, leachate from sodium silicate grouted soil specimens was tested for acute toxicity using Daphnia magna and Vibrio fisheri (Microtox®) assays. Additionally, a soil biometer test was used to measure the aerobic biodegradability of the grout leachate. Median lethal concentrations (LC50s) ranged from 1,220 to 3,260 mg/L as total organic carbon (TOC) for the D. magna test and from 4,500 to 22,180 mg/L as TOC for the Microtox test. More than 80% of the organics contained in the grout leachate were biologically converted to carbon dioxide in less than 30 d. The grout was found to be far less toxic than other common organic chemicals such as phenol.
Optimization of in situ bioassays withHyalella aztecaandChironomus tentans
Authors: Chappie Daniel J , Burton G Allen 
Published: March 2010

AbstractUncertainty is always associated with extrapolations of laboratory toxicity test responsesto in situ conditions. Exposing toxicity test organisms in situ reduces uncertainty by removing sampling related artifacts and better simulating natural exposures. The amphipod Hyalella azteca and the midge Chironomus tentans, were enclosed in plastic containers with 149- or 74-mm mesh openings. These chambers were anchored to stream substrates allowing continual water exchange and contact with sediments. Hyallela azteca survival was greater than 80% after 4 weeks of exposure. In situ testing with H. azteca in cold water (&lt;15°C) resulted in survival consistently below 60%, possibly due to limited acclimation periods. Handling stress during laboratory to field transport reduced C. tentans survival. High survival was not consistently achieved until a protective ground paper towel substrate was used. A smaller mesh size (74 mm) on the chambers reduced the occurrence of indigenous organisms inside the chambers, making C. tentans identification unmistakable. In situ testing with C. tentans using refined methods resulted in greater than 80% survival after 2 weeks of exposure. In situ exposures of these two benthic invertebrates can effectively evaluate short- to long-term conditions of water and sediment quality.
Environmental assessment of a new food ingredient, the fat replacer olestra
Authors: Allgood Gregory S , McAvoy Drew C , Woltering Daniel M 
Published: March 2010

Abstract
Olestra is a new noncaloric food ingredient made from sugar and vegetable oil combined in such a way that it is not digested or absorbed. Olestra will be used to replace the cooking fat and oils used to make savory snacks such as potato chips. An environmental assessment (EA) was conducted to determine whether or not this consumer use of olestra would result in adverse impacts to the environment. The EA was also submitted to the U.S. Food and Drug Administration as part of the agency's review and approval process for this new food ingredient. To provide a conservative assessment, that is, to not underestimate potential environmental risk, exposure estimates were based on an upper-bound annual consumption value of 228 × 106 kg (about 500 million pounds) and the assumption that the entire amount would enter wastewater. The olestra environmental database is extensive and includes studies to address its fate and effects in wastewater treatment systems, sludge-amended soils, and receiving waters. Testing showed olestra was not toxic to aquatic organisms including bacteria, algae, zooplankton, and fish nor to terrestrial organisms including bacteria, plants, earthworms, and nine mammalian species. Testing also showed olestra will not bioconcentrate or persist. Aerobic biodegradation was demonstrated in both aquatic and terrestrial matrices and a plausible mineralization pathway was detailed that has application to both aerobic and anaerobic environments. Because of its very low water solubility (5–42 μg/L) and sorptive nature (Kd ranging from 10,000 to 287,000 L/kg), the vast majority of olestra that enters the environment will be associated with wastewater solids and sludges. Overall removal for primary and secondary treatment was 91 to 94%. Olestra was shown to be mineralized at a rate sufficient to prevent significant accumulation in soil even with annual reapplication of sludge (half-lives were 10–88 d depending upon the physical form [liquid or solid] of olestra). Laboratory and bench scale testing showed olestra did not adversely effect conventional wastewater treatment. Olestra exhibited no adverse effects on total suspended solids or chemical oxygen demand. Olestra's properties are compatible with disposal in landfills and by incineration. Olestra did not adversely impact full-scale septic tanks or physical properties of sludge-amended agricultural soils. Based on conservative exposure estimates and extensive testing, the evidence indicates that consumer use of olestra will not result in adverse effects on wastewater treatment or aquatic and terrestrial ecosystems.