bluuebunny/crossref_metadata_2025_split huggingface dataset:
Trichloroethylene and tetrachloroethylene reduction in a metallic iron–water-vapor batch system
Authors: Campbell Timothy J , Burris David R , Roberts A Lynn , Wells J Raymond 
Published: March 2010

Abstract
The reduction of trichloroethylene (TCE) and tetrachloroethylene (PCE) was examined in ananaerobic batch vapor–water system containing metallic iron. Concentrations of the parent compounds and products (some of which went on to react further) were determined at discrete time intervals during the reactions by analysis of the headspace vapor. cis-1,2-Dichloroethylene, 1,1-dichloroethylene, vinyl chloride, methane, chloroacetylene, acetylene, ethylene, ethane, and C3–5 alkenes and alkanes were observed as products from both compounds. Trichloroethylene was also observed from the reduction of PCE. The masses of unreacted polychlorinated ethylenes sorbed on the iron surface were significant based upon previously determined sorption isotherms, and were incorporated in carbon and chloride recovery estimates. Final carbon and chlorine recoveries of 76% and 104%, respectively, were obtained after a 92% loss of the initial TCE. After the loss of 74% of the initial PCE, the final carbon and chlorine recoveries were 90% and 118%, respectively. Reaction pathways, which include both hydrogenolysis and reductive β-elimination, are proposed to account for the observed products.
Fate and movement of endosulfan under field conditions
Authors: Antonious George F , Byers Matthew E 
Published: March 2010

Abstract
The impact of soil mulches on movement of endosulfan (Thiodan 3 EC) was measured under field conditions. Three soil treatments on a Lowell silty loam soil (5% organic matter) were used to reduce soil erosion and surface water runoff. Living turf mulch (tall fescue) between every cropping row (turf-1), turf every other row (turf-2), and no mulch (NM) treatments were compared. Thiodan was used as foliar single spray on tomato and pepper at the rate of 0.61 kg AI/ha. Following field spraying, runoff water, sediment, and soil samples were collected and analyzed for endosulfan concentration. Endosulfan infiltration through the vadose zone was monitored using pressure-vacuum lysimeters. Studies were also undertaken to determine the magnitude and dissipation of endosulfan stereoisomers (α- and β-endosulfan) and endosulfan sulfate. Analysis of samples was accomplished using gas chromatography (GC) and GC-coupled mass spectrometry (GC-MS). The results confirm the formation of endosulfan sulfate and its significance as a residue component in soil and also the relative persistence of the β-isomer as compared to the α-isomer. Cultivation of turf between cropping rows and pepper intercropped with tomato reduced runoff water and sediment loss and endosulfan movement from application site to surface water runoff. Treatments planted with pepper intercropped with tomato have a tremendous impact on reducing runoff water discharge (67.3% reduction) and sediment loss (85.9% reduction) compared to that planted with pepper plants only. Results indicated the vertical movement of endosulfan through the vadose zone at a concentration of 0.63 μg/L. Soil core data also indicated that endosulfan leached 23 to 46 cm in the soil.
Acute toxicity and aqueous solubility of some condensed thiophenes and their microbial metabolites
Authors: Seymour David T , Verbeek Allen G , Hrudey Steve E , Fedorak Phillip M 
Published: March 2010

Abstract
Petroleum or creosote contamination of surface waters, soils, or groundwaters introduces countless aromatic compounds to these environments. Among these are condensed thiophenes that were shown to be oxidized to sulfoxides, sulfones, and 2,3-diones by microbial cultures. In this study, the acute toxicities of 12 compounds (benzothiophene, benzothiophene sulfone, ben-zothiophene-2,3-dione, 3-, and 5-methylbenzothiophenes, 3-, and 5-methylbenzothiophene sulfones, 5-, and 7-methylbenzothio-phene-2,3-diones, dibenzothiophene, dibenzothiophene sulfoxide, and dibenzothiophene sulfone) were determined by the Microtox® and Daphnia magna bioassays. To aid in determining the toxicities, the solubilities of many of these compounds were determined, which showed that the oxidized compounds were much more water soluble than the parent thiophenes. In nearly every case, the oxidized compounds were less toxic than their parent thiophenes. The Microtox method was more sensitive than the D. magna bioassay, but in general, there was a good correlation between toxicities measured by the two tests. Samples were removed from batch cultures of a Pseudomonas strain capable of oxidizing the thiophenes, and these samples were subjected to Microtox bioassays. These experiments showed that the toxicities of the culture supernatants decreased with incubation time.
Altered locomotory behavior in woodlice (Oniscus asellus (L.)) collected at a polluted site
Authors: Sørensen Freddy F , Weeks Jason M , Baatrup Erik 
Published: March 2010

Abstract
The locomotory behavior of woodlice (Oniscus asellus (L.)) collected along a gradient of pollution from a plastics fire was quantified automatically for 4 h in the laboratory employing computer-aided video tracking. Six locomotory parameters were measured and the corresponding individual body metal concentrations determined. Additional woodlice were collected from the same site for total protein and glycogen analyses. Woodlice collected from the litter layer overlying a pyrolyzed plastic layer spent significantly less time in activity, resulting in a walked distance less than 50% of that of woodlice collected from a nearby reference location. Furthermore, a tendency to turn predominantly in either a left or a right direction and a tendency toward a higher discontinuity in moving was found for the woodlice collected on the pyrolyzed plastic. Overall, the aberrant behavior coincided with significantly elevated body concentrations of heavy metals and lowered protein and glycogen levels. The interference of metals with neurological and metabolic processes is discussed in relation to locomotion.
Genetic differentiation among laboratory populations of Hyalella azteca: Implications for toxicology
Authors: Duan Yihao , Guttman Sheldon I , Oris James T 
Published: March 2010

Abstract
Hyalella azteca of different origins are maintained in many laboratories and are extensively used in toxicological bioassays. Quality assurance of interlaboratory toxicity data can only be made when the amount of genetic differentiation among laboratory populations is known. We assayed genetic variability at 16 enzymatic loci in H. azteca stocks from six laboratories (2 U.S. Environmental Protection Agency [USEPA], 1 U.S. Fish and Wildlife Service [USFWS], University of Mississippi, Environment Canada, Burlington, ON, Canada, and New York Department of Environmental Conservation), as well as an additional species, Hyalella montezuma (used as an outgroup). Three divergent groups were identified in laboratory stocks of H. azteca based on both Nei's genetic identity and modified Rogers' genetic distance. These three groups were differentiated genetically at a level characteristic of distinct species (Nei's I = 0.26–0.69) based on the comparison between H. azteca and H. montezuma. The high level of genetic differentiation among populations indicated that the Burlington and New York populations were distinct species of Hyalella. In order to enhance interlaboratory toxicity test comparisons, we recommend using genetically characterized populations of H. azteca.
Acute toxicity and behavioral effects of chlorpyrifos, permethrin, phenol, strychnine, and 2,4-dinitrophenol to 30-day-old Japanese medaka (Oryzias latipes)
Authors: Rice Patricia J , Drewes Charles D , Klubertanz Theresa M , Bradbury Steven P , Coats Joel R 
Published: March 2010

AbstractFive chemicals with different modes of action were evaluated in laboratory studies to determine their acute toxicity (48-h median lethal concentration [LC50]) and behavioral effects on 30-d-old Japanese medaka (Oryzias latipes). The order of toxicity for these xenobiotics was permethrin &gt; chlorpyrifos &gt; 2,4-dinitrophenol (2,4-DNP) &gt; strychnine &gt; phenol. The 48-h LC50s were significantly different and ranged from 0.011 to 24.1 mg/L. In addition, chlorpyrifos and permethrin accumulated in the tissues of juvenile O. latipes. Observations of five behavioral/morphological responses, including changes in equilibrium, general activity, startle response, and morphology (e.g., hemorrhage and deformities) were used as indicators of sublethal toxicity. Each chemical, with the exception of 2,4-DNP, elicited a distinct behavior or set of behavioral responses. The behavioral toxicology bioassay may be valuable in comparing and predicting the mode of action of new or unknown toxicants in this species of fish.
Resistance to malathion in heat-shocked Daphnia magna
Authors: Bond Jayne-Anne , Bradley Brian P 
Published: March 2010

Abstract
A 34°C heat shock has been shown to induce a transient tolerance to malathion in the cladoceran Daphnia magna. HSP70, a common heat-shock protein, is induced by the same heat shock. Various possible mechanisms exist to explain this heatinducible response. Several enzyme systems are known to be involved in the detoxification of pesticides, including the esterases, transferases, and oxidases. Changes in general esterase, carboxylesterase (Ali esterase, AliE), and glutathione- S-transferase (GST) activities were examined as mechanisms to explain this phenomenon. General esterase activity was not affected by a 34°C heat shock, but was reduced to nearly zero in lethal malathion concentrations, with or without heat shock. Conversely, although AliE activity was reduced by heat shock, there was no further effect of malathion on AliE in either the heat-shocked or control animals. A heatinducible high molecular mass protein complex with GST activity was observed in the resistant daphnids. There was no corresponding increase in GST activity, however. These data suggest that the transient protection against malathion is not caused by an increase in the amount of enzyme or enzyme activity.
Polychlorinated dibenzo-p-dioxins, dibenzofurans, biphenyls and 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents in fishes from Saginaw Bay, Michigan
Authors: Giesy John P , Jude David J , Tillitt Donald E , Gale Robert W , Meadows John C , Zajieck James L , Peterman Paul H , Verbrugge David A , Sanderson J Thomas , Schwartz Ted R , Tuchman Marc L 
Published: March 2010

Abstract
Concentrations of polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polychlorinated naphthalenes (PCNs), polychlorinated dibenzothiophenes (PCDTs), and 2,3,7,8-tetrachlo-rodibenzo-p-dioxin (2,3,7,8-TCDD) equivalents were measured in composite samples of forage fishes and several sizes of walleyes (Stizostedion vitreum) and common carp (Cyprinus carpio) collected from Saginaw Bay, Michigan, USA. The concentrations of 2,3,7,8-TCDD equivalents determined from the use of TCDD equivalency factors (TEFs) and instrumentally determined concentrations of individual congeners were designated TEq. The 2,3,7,8-TCDD equivalents determined on the same extracts with the H4IIE bioassay were defined as TCDD-EQ. Concentrations of TCDD-EQ and TEq were significantly, but poorly correlated (R2 = 0.44). Concentrations of TCDD-EQ and TEq ranged from 10.6 to 348 and 13.5 to 69.5 ng/kg, wet weight, respectively. The ratio of TCDD-EQ to TEq ranged from 0.5 to 5.0, with the greatest ratio observed in common carp but the average ratio between TEq and TCDD-EQ was approximately 1.0. In common carp, larger walleye, and medium-sized alewife (Alosa pseudoharengus) there were significant concentrations of TCDD-EQ that could not be accounted for by TEq calculated from an additive model of PCBs, PCDDs, or PCDFs. As much as 75% of the TCDD-EQ in some samples could not be accounted for by TEqs. It is unlikely that PCNs, PCDTs, or polychlorinated diphenyl ethers (PCDEs) occurred at concentrations that were, based on their relative potencies, great enough to contribute significant quantities of TCDD-EQ. The discrepency between TCDD-EQs and TEqs was not due to antagonisms among congeners or extraction efficiencies.
Heavy metal accumulation in sediment and freshwater fish in U.S. Arctic lakes
Authors: Allen-Gil Susan M , Gubala Chad P , Landers Dixon H , Lasorsa Brenda K , Crecelius Eric A , Curtis Lawrence R 
Published: March 2010

Abstract
Metal concentrations in sediment and two species of freshwater fish (lake trout [Salvelinus namaycush], and grayling [Thymallus arcticus]) were examined in four Arctic lakes in Alaska. Concentrations of several metals were naturally high in the sediment relative to uncontaminated lakes in other Arctic regions and more temperate locations. For example, concentrations of Hg and Ni were 175 ng/g and 250 ng/g dry weight, respectively, in Feniak Lake surface sediment. If any anthropogenic enrichment has occurred, it is not distinguishable from background variability based on surface sediment to down core comparisons. With the exception of Hg, the site rank order of metal concentrations (Cu, Cd, Ni, Pb, and Zn) in sediment and freshwater fish tissue among lakes is not consistent. This suggests that a number of physical, chemical, and physiological parameters mediate metal bioavailability and uptake in these systems. Maximum concentrations of most metals in fish from this study are equal to or higher than those collected from remote Arctic lakes and rivers in Canada, Finland, and Russia. Muscle Hg concentrations in excess of 1 μg/g wet weight were observed in lake trout from Feniak Lake, which has no identified Hg source other than naturally Hg-enriched sediments. Fish diet seems to influence some heavy metal burdens, as evidenced by the higher concentrations of some metals in lake trout compared to grayling, and differences among lakes for lake trout. Cadmium, Cu, and Zn burdens were higher in lakes where snails were consumed by trout compared to lakes without snails.
Accumulation and toxicokinetics of fluoranthene in water-only exposures with freshwater amphipods
Authors: Driscoll Susan Kane , Landrum Peter F , Tigue Elizabeth 
Published: March 2010

Abstract
Two 10-d water-only toxicity tests with radiolabeled fluoranthene were conducted with two species of freshwater amphipods, Hyalella azteca and Diporeia sp. For H. azteca, 10-d median lethal concentrations were 564 nmol/L and 481 nmol/L. Tentative median lethal doses, determined from the regressions of body burden of remaining live H. azteca versus survival, were 5.6 and 3.6 mmol fluoranthene/kg wet weight tissue. Diporeia appeared to be less sensitive, because survival in Diporeia was greater than 84% after 10-d exposures. Elimination rates determined for Diporeia, ranging from 0.0011 to 0.0042/h (half-lives of 7–26 d), were much slower than rates determined for H. azteca of 0.128 to 0.188/h (half-lives of 4–6 h). Faster elimination in H. azteca may be related to its greater ability to metabolize fluoranthene. For H. azteca, an average of 17% of its body burden was present as metabolites after 24 h of exposure to radiolabeled fluoranthene, as compared to 5% for Diporeia. For Diporeia, exposure to various water concentrations of fluoranthene for various lengths of time resulted in declines in the conditional uptake clearance rates (ml water cleared/g wet weight tissue/h). A similar, although less dramatic trend was observed for conditional uptake clearance rates in H. azteca.
Effects of alachlor on an algal community from a midwestern agricultural stream
Authors: Spawn Rebecca L , Hoagland Kyle D , Siegfried Blair D 
Published: March 2010

AbstractThe effects of a single pulse, 21-d exposure of the commonly used herbici de a achlor (2-chloro-2′, 6′-diethyl-N-methoxymethyl acetanilide) on an algal community from a typical agricultural stream in Nebraska were studied using 18 stream microcosms located in a greenhouse, at six alachlor concentrations (0, 1, 10, 30, 100, and 1,000 μg/L). Effects of alachlor exposure at 1.0 μg/L were not significant (p &lt; 0.05); however, at all other concentrations, alachlor had a significant negative effect on algal biomass. Differential taxonomic responses were observed, with approximately half the dominant algal taxa affected at levels &gt;10 μg/L. Some taxa recovered from exposure by day 7, while others took longer or did not recover. A shift in the dominant algae was observed at higher concentrations (30, 100, 1,000 μg/L), and after 21 d these streams exhibited total algal cell densities significantly lower than the control and 1.0-μg/L-level streams. Results of this study suggest that alachlor inputs can alter both algal community composition and biomass in agricultural streams. Consequently, potential indirect impacts of alachlor on higher trophic levels warrant further investigation.
Study of heavy metals and other elements in macrophyte algae using energy-dispersive x-ray fluorescence
Authors: Carvalho Maria L , Ferreira Joao, G , Amorim Pedro , Marques Maria I M , Ramos Maria T 
Published: March 2010

Abstract
Fucus vesiculosus L. seaweeds from three estuarine stations were analyzed by X-ray fluorescence, providing results for the concentration of total K, Ca, Ti, Mn, Fe, Co, Ni, Cu, Zn, As, Br, Sr, and Pb. Four different structures of the algae (base, stipe, reproductive organs, and growing tips) were analyzed to study the differential accumulation of heavy metals by different parts of Fucus. Some elements (e.g., Cu and Fe) are preferentially accumulated in the base of the algae, whereas others (e.g., As) exhibit higher concentrations in the reproductive organs and growing tips. The pattern of accumulation in different structures is similar for Cu, Zn, and Pb, but for other metals there is considerable variability in accumulation between parts of the plant. This is important in determining which structures of the plant should be used for biomonitoring. For samples collected at stations subject to differing metal loads, the relative elemental composition is approximately constant, notwithstanding significant variation in absolute values. The proportion of metals in Fucus is similar to that found in other estuaries, where metal concentrations are significantly lower. Energy-dispersive X-ray fluorescence has been shown to be a suitable technique for multielement analysis in this type of sample. No chemical pretreatment is required, minimizing sample contamination. The small amount of sample required, and the wide range of elements that can be detected simultaneously make energy-dispersive X-ray fluorescence a valuable tool for pollution studies.
Effect of acclimation period on the relationship of acute copper toxicity to water hardness for fathead minnows
Authors: Erickson Russell J , Kleiner Charles F , Fiandt James T , Highland Terry L 
Published: March 2010

Abstract
The acute (96-h) toxicity of copper sulfate to fathead minnows was tested in a 2 × 2 factorial experiment, with factors being low (ca. 1 meq/L) and high (ca. 4 meq/L) water hardness during an acclimation period and low and high hardness during the exposure period. Acclimation hardness was found to have no significant effects on copper lethality, except that the 24-h LC50 at high exposure hardness was 44% higher for fish subject to low acclimation hardness than fish subject to high acclimation hardness. In contrast, exposure hardness was found to have major effects, with LC50s being two to three times greater at high exposure hardness than at low, regardless of the acclimation hardness. These results suggest that the extent of the acclimation period is not a general, severely confounding factor for previous reports of the effects of hardness on copper toxicity to fish, although it may assume some importance for some species and test conditions.
Comparative metabolism of benzo[a]pyrene by liver microsomes of channel catfish and brown bullhead
Authors: Yuan Zhi-Xin , Kumar Subodh , Sikka Harish C 
Published: March 2010

Abstract
We investigated the metabolism of the carcinogen benzo[a]pyrene (BaP) by liver microsomes of channel catfish (Ictalurus punctatus) and brown bullhead (Ameiurus nebulosus) pretreated with 3-methylcholanthrene. The catfish liver microsomes metabolized BaP at a considerably lower rate than did the brown bullhead liver microsomes. Although the BaP metabolites produced by the liver microsomes of the two species were qualitatively similiar, there were considerable differences in the relative proportions of individual metabolites formed. The catfish liver microsomes produced a considerably lower proportion of benzo-ring diols of BaP including BaP-7,8-diol (the proximate carcinogenic metabolite of BaP) than did the bullhead liver microsomes. Compared to the bullhead liver microsomes, the catfish microsomes converted a higher proportion of BaP to phenolic metabolites.
Inhibitory effects of 2-mercaptobenzothiazole on microbial growth in a variety of trophic conditions
Authors: De Wever Helene , Van den Neste Saskia , Verachtert Hubert 
Published: March 2010

Abstract
2-Mercaptobenzothiazole (MBT) is found mainly in the wastewaters of its industrial production as a rubber vulcanization accelerator. Because this compound was found to be toxic to activated sludges and because it causes poor process performances, its impact on bacteria in particular was studied. 2-Mercaptobenzothiazole, but not other benzothiazoles, exerted mainly bacteriostatic effects towards Escherichia coli, Sarcina lutea, Staphylococcus aureus, and a 2-hydroxybenzothiazole-degrading isolate (OBT18). It caused membrane disturbance as measured by induced potassium effluxes from the cell. Emphasis was on the effects of MBT on growth of E. coli on different electron donor-electron acceptor combinations. Paracoccus denitrificans was grown in the presence of oxygen or nitrate and the yeast Saccharomyces cerevisiae was used under aerobic and fermentative conditions. In almost all conditions the growth was severely inhibited, indicating that MBT might interfere with a common oxidoreduction step in membrane-bound systems and probably also interferes with metabolic reactions not related to the respiratory chain.
Toxicity of a pah photooxidation product to the bacteria Photobacterium phosphoreum and the duckweed Lemna gibba: Effects of phenanthrene and its primary photoproduct, phenanthrenequinone
Authors: McConkey Brendan J , Duxbury Cheryl L , Dixon D George , Greenberg Bruce M 
Published: March 2010

Abstract
Phenanthrene (PHE) undergoes a significant increase in toxicity after exposure to simulated or natural sunlight in aqueous media, coincident with the appearance of PHE photoproducts. To investigate whether the primary photoproduct of PHE, 9,10-phenanthrenequinone (PHEQ), contributes to the increased hazards of solutions containing photomodified PHE, toxicity assays were conducted using the marine bacteria Photobacterium phosphoreum and the aquatic plant Lemna gibba (duckweed). Photo-bacterium phosphoreum was exposed to PHE, PHEQ, a photomodified PHE mixture containing known amounts of PHE and PHEQ (pmPHE), and a mixture mimicking the amounts of PHE and PHEQ in the pmPHE mixture. The bacteria were found to be equally sensitive to PHE in simulated solar radiation (SSR, a light source with a visible light : UVA : UVB ratio similar to that of sunlight) or darkness, with an EC50 of 0.53 mg/L. In both darkness or SSR, solutions containing PHEQ (with or without PHE) all exhibited an EC50 of 0.06 to 0.10 mg/L based on PHEQ concentrations, indicating that PHEQ was the primary active component of the pmPHE mixture. Lemna gibba was tested in SSR and visible light with PHE, PHEQ, and the pmPHE mixture. The calculated EC50 for PHE was 3.5 mg/L in SSR and 10.8 mg/L in visible light, showing that the presence of UV radiation in the SSR source increased the phytotoxicity of PHE. Strikingly, PHEQ was much more toxic to L. gibba than PHE in a light-independent manner (an EC50 of 0.53 and 0.57 mg/L PHEQ in dark and SSR, respectively). Thus, for both P. phosphoreum and L. gibba the major photooxidation product of PHE in SSR, PHEQ, is the more toxic of the two chemicals.