bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sorption and bioavailability of carbon tetrachloride in a low organic content sandy soil
Authors: Zhao Xianda , Szafranski Michael J , Maraqa Munjed A , Voice Thomas C 
Published: March 2010

AbstractTwo sets of parallel columns were packed with a low-organic-content aquifer soil contaminated with carbon tetrachloride (CT) and flushed with water under bioactive and abiotic saturated conditions. Both effluent and soil concentrations (by sacrificing columns) were monitored for CT. Desorption of CT from the aquifer material could be described by a two-site nonequilibrium model. The columns were found to operate far from desorption equilibrium conditions. Inoculation with Pseudomonas sp. strain KC resulted in rapid transformation of CT in the liquid phase, but no evidence of solid-phase degradation was found. Mathematical modeling of desorption and biodegradation as sequential and independent processes appears to be justified for this soil/contaminant combination.
Reduction of 1,2-dibromoethane in the presence of zero-valent iron
Authors: Rajagopal Venkat K , Burris David R 
Published: March 2010

AbstractThe degradation reaction of 1,2-dibromoethane (ethylene dibromide or EDB) in water was studied in the presence of zero-valent iron (acid-cleaned, cast iron) in well-mixed batch aqueous systems. The observed products were ethylene and bromide ions. Carbon and bromine mass recoveries of ≥ 95% were obtained. Bromoethane and vinyl bromide were not observed. The reduction rates of bromoethane and vinyl bromide with iron indicate that they should have been observed if they were significant reaction intermediates for EDB. The results indicate that reductive β-elimination may be the dominant reaction pathway. Reaction kinetics are rapid and pseudo-first order. The activation energy was determined to be 50 kJ/mol, indicating that the reaction rate may not be aqueous phase diffusion controlled but rather controlled by the chemical reaction rate on the iron surface. Metallic iron may be a suitable treatment approach for EDB-contaminated groundwater in above-ground, as well as in situ applications, due to rapid kinetics and nontoxic products.
Chronic toxicity of 2,4,6-trinitrotoluene to a marine polychaete and an estuarine amphipod
Authors: Green Andrew , Moore David , Farrar And Daniel 
Published: March 2010

AbstractThe chronic toxicity of sediment-associated 2,4,6-trinitrotoluene (TNT) to the marine polychaete Neanthes arenaceodentata and the estuarine amphipod Leptocheirus plumulosus was evaluated. Test organisms were exposed to sediments spiked with radiolabeled TNT for 28 d, after which time the endpoints of mortality, growth, and reproduction (L. plumulosus only) were assayed and compared against the TNT tissue concentrations as well as the TNT sediment concentrations. Survival was significantly reduced at a tissue concentration of 61 μg TNT/g wet wt tissue in N. arenaceodentata and at 6.3 μg TNT/g wet wt tissue in L. plumulosus. The growth end point demonstrated an apparent hormesis effect in both N. arenaceodentata and L. plumulosus with enhancement (significant for N. arenaceodentata) occurring at the lower TNT concentrations. Growth was significantly reduced at the highest TNT exposure of 10.0 μg TNT/g wet wt tissue in L. plumulosus. Reproduction was significantly reduced at a tissue concentration of 6.3 μg TNT/g wet wt tissue in L. plumulosus. The results of this study demonstrate that both N. arenaceodentata and L. plumulosus are sensitive to the presence of sediment-associated TNT and that more information is needed about the toxicity of TNT to benthic fauna to facilitate risk assessment and management of TNT-contaminated sites.
Direct effect of ammonia on three species of north american anuran amphibians
Authors: Jofre Mariana B , Karasov William H 
Published: March 2010

AbstractLeopard frog (Rana pipiens), green frog (Rana clamitans), and American toad (Bufo americanus) embryos were exposed to different un-ionized ammonia (NH3) levels over an ecologically relevant range (0–2 mg NH3/L H2O). Hatching success and prevalence of deformities were recorded after acute exposures (3–5 d duration) at 23°C and pH 8.7. Green frog tadpoles were exposed to different NH3 levels in a subchronic experiment (114 d), and growth, survival, and metamorphosis were monitored. Survival declined, the prevalence of deformities increased, and growth and development were slow in anuran embryos and tadpoles exposed to NH3 concentrations in excess of 0.6 mg/L (green frogs) or 1.5 mg/L (leopard frogs). No effects were observed in American toads up to a concentration of 0.9 mg/L NH3. It appears from the few data available that anurans may not be particularly sensitive to NH3 when compared with many fish species and that water quality criteria determined using data collected on fish species will be protective for many anuran amphibians. The NH3 concentrations that caused negative effects in these experiments are higher than measured values for water in the Fox River–Green Bay ecosystem (WI, USA) but lower than for pore sediment water. In this ecosystem, anuran amphibians are potentially exposed to hazardous levels of NH3 when they hibernate on the bottom or buried in sediments or during episodic releases of NH3 from sediments.
Whole-fish versus filet polychlorinated-biphenyl concentrations: An analysis using classification and regression tree models
Authors: Amrhein James F , Stow Craig A , Wible Clay 
Published: March 2010

Abstract
Fish polychlorinated-biphenyl (PCB) measurements usually represent one of two different sample types: filets or homogenized whole fish. Filet measurements are more appropriate for use if the goal of analysis is estimating human PCB consumption, while whole-fish analysis may be more useful for quantifying and understanding processes of contaminant flow and bioaccumulation. While it is generally assumed that whole-fish PCB concentrations exceed filet concentrations because of the presence of fatty internal organs in whole-fish samples, the literature contains no reported comparisons of filet versus whole-fish PCB concentrations. We measured total PCB concentrations in filets and whole-fish samples from the same individuals in Lake Michigan coho salmon (Oncorhynchus kisutch) and rainbow trout (Oncorhynchus mykiss). The average whole-fish to filet PCB concentration ratio was 1.70 for coho salmon and 1.47 for rainbow trout, but it varied considerably among individuals, with a few fish exhibiting a higher concentration in the filet than in the whole-fish sample. Classification and regression tree (CART) models indicated that filet PCB concentration and fish length were the best predictors of whole-fish PCB concentration, whereas filet and whole-fish lipid concentrations where less important predictors. Lipid normalization of the PCB data decreased within-individual variability, was equivocal with respect to variability among individuals, and accentuated the between-species difference. Both species exhibit a pronounced 1:1 relationship between the whole-fish to filet PCB concentration ratio and the whole-fish to filet lipid concentration ratio; however, we point out that there is a strong spurious component to this relationship, which indicates that the relationship may be more algebraic rather than an indication of underlying mechanisms.
Gray-tailed voles do not move to avoid exposure to the insecticide Guthion® 2S
Authors: Wang Guiming , Wolff Jerry O , Edge W Daniel 
Published: March 2010

Abstract
We used the gray-tailed vole, Microtus canicaudus, as an experimental model species to test an assumption of the quotient method that nontarget wildlife do not move out of a contaminated area to avoid exposure to potentially harmful agricultural chemicals. In May 1997, we placed voles into 12 0.2-ha enclosures planted with a mixture of pasture grasses. In late July, we applied 1.5 kg/ha of the insecticide Guthiont 2S (azinphos-methyl), in three treatments; full spray (all of the habitat sprayed with Guthion 2S), half spray (one half of the habitat sprayed with Guthion 2S and one half sprayed with water), and a control (all of the habitat sprayed with water). Five replicates were used for the half spray and control, and two replicates were used for the full spray. We radio-tracked 44 female and three male voles before and after the spray treatment. None of the 47 animals moved out of their established home ranges after treatment and no animals moved from the contaminated to uncontaminated areas. Additionally, no biologically meaningful differences occurred in home range size, mean maximum distance moved, or average distance between two successive radio locations. Reproducing adult voles were relatively sedentary and did not leave their established home ranges in response to insecticide exposure. These results suggest that small mammals are not likely to reduce exposure by moving from the contaminated area, which supports the assumption of the quotient method that exposure of small mammals is a function of the spray application. However, behavioral responses such as avoidance of contamination may be specific to the chemical, species, and habitat.
Factors affecting the development of testis-ova in medaka, Oryzias latipes, exposed to octylphenol
Authors: Gray Michelle A , Niimi Art J , Metcalfe Chris D 
Published: March 2010

Abstract
There are many endocrine-disrupting chemicals in the environment that have the potential to alter the development of sexual characteristics in fish and wildlife. Little is known about the factors that influence the development of an intersex condition in fish. Japanese medaka (Oryzias latipes) were exposed to octylphenol (OP), a known estrogen agonist, during various life history stages to determine the factors that control induction of testis-ova, an intersex condition. In male medaka exposed to OP (100 μg/L) beginning at 1, 3, 7, 21, and 35 d posthatch, the incidence of testis-ova at 100 d posthatch was highest in the 3-d posthatch treatment (4 of 14 males) and declined when exposures were initiated with older fry. Exposure to OP (100 μg/L) from hatch for a period of 1 or 2 months did not induce testis-ova, but exposure for 3 months resulted in 3 of 50 males developing this condition. Exposures of adult male medaka to OP (200 and 300 μg/L) for either 18 or 36 d resulted in only one testis-ova in a male fish exposed for 36 d to the highest nominal concentration. In addition to testis-ova, male medaka exposed to OP developed testicular fibrosis. Overall, these data indicate that prolonged exposure of male medaka to an estrogen agonist beginning around the period of gonadal differentiation is optimal for the development of testis-ova, but this intersex condition can be induced when exposure begins at later life stages.
Arsenate sensitivity in ericoid and ectomycorrhizal fungi
Authors: Sharples Jade M , Meharg Andrew A , Chambers Susan M , Cairney John W.G 
Published: March 2010

Abstract
Isolates of the endomycorrhizal fungus Hymenoscyphus ericae and the ectomycorrhizal fungus Hebeloma crustuliniforme from soils uncontaminated with AsO3−4, were compared with regard to their sensitivity to AsO3−4 in solution culture. When grown 4 4 in liquid media amended with a range of AsO3−4 concentrations, H. ericae demonstrated reduced sensitivity to AsO3−4 compared to H. crustuliniforme. The concentrations causing 50% inhibition of growth (EC50) were 1.33 mol/m3 and 0.33 mol/m3, respectively, for H. ericae and H. crustuliniforme. The compound AsO3−4 is a PO3−4 analogue for the plasmalemma PO3−4 transporter. The presence of PO3−4 in the media at high concentrations ameliorated the toxic effects of AsO3−4 in both the ericoid and ectomycorrhizal fungi. This could be due to both suppression of the PO3−4 transporter under high phosporus status and competition of PO3−4 with AsO3−4 for the transport protein. The kinetics of AsO3−4 influx in H. ericae and H. crustuliniforme were also investigated. Hymenoscyphus ericae demonstrated a high Km value, 0.071 mol/m3, consistent with values obtained for AsO3−4 -tolerant plants. We suggest that the high Km value may be a mechanism used by H. ericae to express reduced AsO3−4 sensitivity. The ecological significance of this reduced sensitivity is also discussed.
Temperature dependence of Henry's law constants of thirteen polycyclic aromatic hydrocarbons between 4°C AND 31°C
Authors: Bamford Holly A , Poster DIanne L , Baker Joel E 
Published: March 2010

Abstract
An understanding of the temperature dependence of the Henry's law constant for organic contaminants is critical when modeling the transport and fate of these contaminants in the environment. The Henry's law constants for 13 polycyclic aromatic hydrocarbons (PAHs) were experimentally determined between 4 and 31°C using a gas-stripping apparatus. The Henry's law constants ranged between 0.02 ± 0.01 Pa m3/mol for chrysene at 4°C and 73.3 ± 20 Pa m3/mol for 2-methylnaphthalene at 31°C. The temperature dependence of each PAH was modeled using the van't Hoff equation to calculate the enthalpy and entropy of phase change. For nine of the PAHs, the present study reports the first experimental measured temperature dependence of their Henry's law constant. The enthalpies of phase change ranged between 35.4 ± 1.9 kJ/mol for 1-methylphenanthrene and 100 ± 8 kJ/mol for chrysene. These data can be used to extrapolate Henry's law values within the experimental temperature ranges. For all PAHs except benzo[a]fluorene, the temperature dependence can be predicted within a relative standard error &lt;10%.
Effects of chronic, low concentrations of dietary methylmercury on the behavior of juvenile great egrets
Authors: Bouton Shannon N , Frederick Peter C , Spalding Marilyn G , McGill Heather 
Published: March 2010

AbstractWe measured the behavioral effects of methylmercury on 16 great egret chicks (Ardea albus) in a captive dosing experiment. Birds were randomly divided into a control group and groups that received 0.5 or 5 mg methylmercury chloride per kilogram of food at between 12 and 105 d of age. We recorded activity levels, maintenance behavior, and foraging efficiency and determined that mercury affected activity and maintenance behavior. Birds dosed with 5 mg/kg became severely ataxic and were euthanized by 12 weeks of age. We found that, during the postfledging period, there were no differences between low-dose and placebo birds in time required to capture live fish in pools or in efficiency of capture. We did find that low-dose birds were less likely to hunt fish. Our results suggest that, at the 0.5 mg/kg concentration in food, there are significant effects of methylmercury on activity, tendency to seek shade, and motivation to hunt prey.
Test chambers and test procedures for in situ toxicity testing with zooplankton
Authors: Pereira Anabela Maria Maia , da Maia Soares Amadeu Mortágua Velho , Gonçalves Fernando , Ribeiro Rui 
Published: March 2010

Abstract
Ecotoxicity assessment is usually done by classical tests under controlled conditions. However, field situations may not be accurately predicted by laboratory testing. In situ testing is a pertinent way for assessing the ecological relevance of laboratory bioassays. The objectives of this study were to develop an in situ test chamber and respective test protocols suitable for ecotoxicity testing with zooplankton and to evaluate the use of laboratory protocols (water column and solid phase) by comparing results obtained under controlled conditions with in situ results at an aquatic system receiving acid mine drainage. At the most contaminated stations and at the reference stations, good agreement was found between in situ and classical testing. At intermediate stations, in situ toxicity was generally higher than that in classical tests. Sample collection and preservation probably altered actual toxicity, thus emphasizing the need for caution in estimating or extrapolating field effects from laboratory results.
Survival and behavioral responses of larvae of the caddisfly Hydropsyche angustipennis to copper and diazinon
Authors: Van der Geest Harm G , Greve Gerdit D , de Haas Elske M , Scheper Bonnie B , Kraak Michiel H S , Stuijfzand Suzanne C , Augustijn Kees H , Admiraal Wim 
Published: March 2010

Abstract
This study reports on newly developed short-term survival and behavioral tests with larvae of the caddisfly Hydropsyche angustipennis using two model toxicants, copper and diazinon. Mortality of first instar larvae was shown to be a reliable endpoint, and it was demonstrated that H. angustipennis is among the more sensitive aquatic insects in terms of both copper and diazinon. In addition, short-term behavioral responses were found to be indicative of adverse effects of ecologically relevant low doses of copper. Using the tests developed in this study, hydropsychid species are excellent tools for discerning the effects of individual toxicants present in large European rivers, and these species may help in defining the conditions for ecological rehabilitation.
Long-term effects of toxaphene and depuration in lake trout and white sucker in a natural ecosystem
Authors: Delorme Peter D , Lockhart W Lyle , Mills Kenneth H , Muir Derek C G 
Published: March 2010

Abstract
Individuals from lake trout (Salvelinus namaycush) and white sucker (Catastomus commersoni) populations in a small lake located in the Experimental Lakes Area in northwestern Ontario, Canada, were treated with single intraperitoneal injections of toxaphene (7 μg/g or 3.5 μg/g) to better understand its potential effects on fish in their natural environment. Wild fish were captured, tagged, weighed, measured, injected with toxaphene, and released back into the lake. They were subsequently recaptured during spring (white sucker) and fall (lake trout) for the next 5 years. In years 2 and 3 following treatment, fish were spawned to assess reproductive success and survival of their offspring. Survival of adult lake trout and white sucker treated with toxaphene was decreased compared with controls. No changes in growth were evident in either species due to toxaphene treatment. No differences occurred in fertilization rate, total survival, or incidence of deformities in eggs and fry from female lake trout treated with toxaphene. Fertilization rates and survival to swim-up of white sucker eggs and fry from females treated with toxaphene decreased relative to controls in both years. Maternal transfer of toxaphene from female to eggs was observed in both white sucker and lake trout; levels in eggs were much lower than in treated females but were still significantly higher than in controls. Residue analyses showed that depuration of toxaphene was slower than expected, with estimated half-lives of 314 and 793 d in lake trout and white sucker, respectively.
Relationship between polychlorinated biphenyl 126 treatment and cytochrome p4501a activity in chickens, as measured by in vivo caffeine and ex vivo ethoxyresorufin metabolism
Authors: Feyk Lori A , Giesy John P , Lambert George H 
Published: March 2010

AbstractCytochrome P4501A (CYP1A) activity is often used as a biomarker of exposure of wildlife to polyhalogenated diaromatic hydrocarbons (PHDHs) and is usually measured ex vivo in liver tissue. A caffeine breath test with radiolabelled substrate (14C-CBT) has been developed to measure in vivo avian CYP1A activity. Research goals were to develop stable isotope methods (13C-CBT), determine dose-response relationships between caffeine N-demethylation (CNDM) and PHDH exposure, and assess the relative utility of the CBT and ex vivo ethoxyresorufin-O-deethylase (EROD) assay. The 13C-CBT methods were developed with 20 chickens (Gallus domesticus). Chickens received three intraperitoneal injections of 0, 1, 5, or 50 μg 3,3′,4,4′,5-pentachloro-biphenyl (PCB 126)/kg body weight, and CNDM was quantified by measurement of 13CO2/12CO2 in expired breath. The 13C-CBT was not as sensitive or specific as the EROD assay as an indicator of PHDH exposure and effect in birds. Constitutive CNDM of great interindividual variability was observed, and the magnitude of induction was greater for EROD activity than for CNDM (approximately 1,000- and 2-fold, respectively). Variability associated with baseline 13CO2/12CO2 ratios in expired breath reduced the sensitivity of the 13C-CBT method.
Toxicity testing of organic chemicals in groundwater polluted with landfill leachate
Authors: Baun Anders , Kløft Lene , Bjerg Poul L , Nyholm Niels 
Published: March 2010

Abstract
A method for assessment of toxicity of nonvolatile organic chemicals contaminants in groundwater polluted with landfill leachate has been evaluated. The biotests utilized were comprosed of an algal growth inhibition test (Selenastrum capricornutum), a daphnia immobilization test (Daphnia magna), and a bacterial genotoxicity test (umuC, Salmonella typhimurium). The feasibility of the selected biotests was investigated for a series of groundwater samples collected along pollution gradients downstreams of two landfills in Jutland, Denmark. Two different approaches were used, direct toxicity testing of whole groundwater samples, and toxicity testing of concentrates obtained by solid-phase extraction. Direct testing of whole groundwater samples produced toxic responses, but the complex sample matrix masked the toxicity of the organic chemical contaminants of interest. Solid-phase extraction was used successfully as an on-site method that eliminated ion toxicity and produced biotest responses that reflected the toxicity of the nonvolatile organic chemical contaminants in the groundwater.
Productivity, diets, and environmental contaminants in nesting bald eagles from the aleutian archipelago
Authors: Anthony Robert G , Miles A Keith , Estes James A , Isaacs Frank B 
Published: March 2010

Abstract
We studied productivity, diets, and environmental contaminants in nesting bald eagles from the western Aleutian Islands, Alaska, USA, during the summers of 1993 and 1994. Productivity on Adak, Tanaga, and Amchitka Islands ranged from 0.88 to 1.24 young produced per occupied site and was comparable to that of healthy populations in the lower 48 United States. However, productivity on Kiska Island was depressed, averaging 0.67 young per occupied site. The lower reproductive success on Kiska was associated with elevated levels of dichlorodiphenyldichloroethylene and other organochlorine pesticides. Many of the organochlorine pesticides were elevated in bald eagle eggs from the four islands, but concentrations of these contaminants and Hg were significantly higher in eggs from Kiska Island than in eggs from the other islands. In contrast, polychlorinated biphenyl concentrations were higher in eggs from Adak, Amchitka, and Kiska (where military facilities have been installed) than in those from Tanaga (which has had little military activity). The most likely source of these contaminants in bald eagles was from their diets, which were variable spatially and temporally. Fish made up most (56%) of the eagles' diet on Adak and Tanaga Islands, followed by birds (25%) and mammals (19%). In contrast, birds comprised the majority (60%) of bald eagle diets on Amchitka and Kiska Islands, followed by mammals (30%) and fish (10%). The high proportion of seabirds in the diet of eagles from Kiska Island could be the major source of organochlorine and Hg contamination. Elevated concentrations of organochlorines in bald eagle eggs from the Aleutian Archipelago was surprising, because of the distance to agricultural areas. The results indicate that these contaminants can be transported long distances and affect wildlife populations in remote and pristine areas. We also discuss potential sources and transport mechanisms of these contaminants to the Aleutian Islands.