bluuebunny/crossref_metadata_2025_split huggingface dataset:
Concentration dependence of bis(tributyl)tin oxide accumulation in the mussel, mytilus edulis
Authors: Laughlin Roy B. , French Willie 
Published: March 2010

Abstract
Mussels, Mytilus edulis, were exposed in a daily static renewal protocol to five different [l‒14C]bis(tributyl)tin (TBT) concentrations: 23, 45, 63, 141 or 670 ng L‒1. The time course of accumulation in four tissues (gills, viscera, adductor muscle and mantle) was determined for a period of 2 to 7 weeks. The pattern of uptake was strongly concentration‒dependent. In both 23 and 45 ng L‒1 concentrations, an apparent steady state was reached within two weeks. At exposure concentrations of 63 ng L‒1 and above, tissue burdens did not reach a steady state within an observation period of six weeks and increased in proportion to exposure concentration. TBT concentrations in tissues were ranked as follows: gills » viscera &gt; adductor muscle ≈ mantle, with gill concentrations consistently dominating those in other tissues throughout exposure. Bioconcentration factors for TBT in mussels were greater (estimated to be in the range of 1,500 to 7,300) than would be predicted from the Kow value. These studies suggest that M. edulis would be a potentially useful sentinel organism for TBT above a threshold concentration in the marine environment. This threshold appears to be near a value that distinguishes areas receiving direct inputs of antifouling paints from those that do not.
Comparative uptake of hexachlorobenzene by fathead minnows, amphipods and oligochaete worms from water and sediment
Authors: Schuytema Gerald S. , Krawczyk Daniel F. , Grlffis William L. , Nebeker Alan V. , Robideaux Merline L. , Brownawell Bruce J. , Westall John C. 
Published: March 2010

AbstractFathead minnows (Pimephales promelas), the worm Lumbriculus variegatus and the amphipod Hyalella azteca were exposed in static tests to hexachlorobenzene (HCB) in water with and without HCB‒spiked sediment to evaluate the relative importance of water and sediment as routes of uptake. The concentration of HCB in water was maintained by passing air saturated with HCB vapor through the test vessels. The presence of HCB‒spiked sediment did not result in a significant increase in bioconcentration factor in two tests with H. azteca. The presence of HCB‒spiked sediment did significantly increase the bioconcentration factor in two tests with fathead minnows and in one of three tests with L. variegatus. The gas phase transfer method was efficient at maintaining a reasonably constant concentration of HCB in water. However, complete control of the aqueous phase activity of HCB through gas phase transfer was not achieved because of the source/sink capacity of the sediment, organisms and food.
Estimation of environmental and toxicological properties: Approach and methodology
Authors: Hall Lowell H. , Kier Lemont B. 
Published: March 2010

Abstract
The estimation of properties of environmental interest is discussed. A general method for estimation based on molecular topology is presented and examples given for several studies. The most widely used topological method is based on the molecular connectivity indexes, which represent molecular structure in numerical form. Other methods presented include shape indexes and an additivity model. The variety of examples discussed and references given indicates the vitality of the use of molecular topology.
Structure-Activity relationships for photooxidation processes in the environment
Authors: Mill Theodore 
Published: March 2010

Abstract
Photooxidation of organic compounds takes place by direct and indirect photoprocesses. Generally, direct photooxidation rate constants cannot be predicted by currently available structure-activity relationships (SARs). Indirect photooxidation processes, in which photogenerated oxidants react with chemicals by electron or H-atom transfer or addition to unsaturated centers, are well understood and rate constants are strongly correlated with structure. This article reviews SARs for predicting rate constants for reactions of HO radical and ozone in the troposphere, and ROn radicals and singlet oxygen in water for reactive organic compounds, and discusses the identification, measurement and reactivity of these oxidants.
Physicochemical properties as predictors of organic chemical effects on soil microbial respiration
Authors: Walton Barbara T. , Anderson Todd A. , Hendricks Marilyn S. , Talmage Sylvia S. 
Published: March 2010

Abstract
Structure-activity analysis was used to evaluate the effects of 19 hazardous organic chemicals on microbial respiration in two slightly acidic soils (a Captina silt loam from Roane County Tennessee, and a McLaurin sandy loam from Stone County, Mississippi), both low in organic car bon and typical of the southeastern United States. Single additions of individual chemicals were applied at 1,000 μg/g (dry weight) soil, which was moistened to 80% base saturation and incubated in the dark at 20°C. CO2 efflux from the soils was monitored at 24-h intervals over a 6-d period The chemicals included in the study were the following: acrylonitrile, furan, methyl ethyl ketone tetrahydrofuran, benzene, toluene, 1,2-dichloroethane, p-xylene, chlorobenzene, chloroform nitrobenzene, trans-1,4-dichloro-2-butene, cis-1,4-dichloro-2-butene, 1,2-dichlorobenzene, 1,2,3 trichloropropane, carbon tetrachloride, 1,2-dibromoethane (ethylene dibromide), 1,2,4,5 tetrachlorobenzene and hexachlorobenzene.
Seventeen of the chemicals caused temporary depressions in CO2 efflux in at least one soil, bu treatments were not significantly different from controls by the sixth day for most of these com pounds, indicating the ability of the microbial community to recover from chemically induced toxicity at this concentration. Acrylonitrile, nitrobenzene, and the 1,4-dichloro-2-butenes causec sustained depressions, whereas methyl ethyl ketone and benzene increased respiration.
The octanol/water partition coefficient (KOW) and molecular connectivity (1x) gave good correlations with effects on soil respiration for a subset of benzene and the six alkyl- and chloro substituted derivatives (i.e., toluene, p-xylene, chlorobenzene, 1,2-dichlorobenzene, 1,2,4,5-tetra chlorobenzene and hexachlorobenzene).
Adaptation of aquifer microbial communities to the biodegradation of xenobiotic compounds: Influence of substrate concentration and preexposure
Authors: Aelion C. Marjorie , Dobbins Durell C. , Pfaender Frederic K. 
Published: March 2010

Abstract
Studies were conducted to examine the adaptation response of aquifer microbial communities to xenobiotic compounds and the influence of chemical preexposure in the laboratory and in situ on adaptation. Adaptation and biodegradation were assessed as mineralization and cellular incorporation of 14C-radiolabeled substrates. For some compounds, such as ethylene dibromide, aniline and m-nitrophenol, biodegradation and adaptation rates were not influenced by chemical concentration over the range tested. Biodegradation rates increased with concentration for p-chlorophenol, and a gradient of adaptation and biodegradation responses was observed for p-nitrophenol up to a threshold concentration. Acclimation to laboratory conditions decreased but did not eliminate the adaptation period to p-nitrophenol. Laboratory adaptation studies and examination of uncontaminated and contaminated field samples from a single aquifer indicated that adaptation was accompanied by shifts in the metabolic fate of the substrate. The increased metabolism associated with adapted communities was predominantly the result of increased mineralization. Cellular incorporation represented a significantly smaller fraction of total metabolism in the adapted versus the unadapted communities. The results indicate that the adaptation response in aquifer solids is due to a complex set of interactions that are influenced by the physiology and growth of the degrading populations.
Uptake, elimination and tissue distribution of dietary and aqueous cadmium by rainbow trout (salmo gairdneri richardson) and lake whitefish (coregonus clupeaformis mitchill)
Authors: Harrison S. E. , Klaverkamp J. F. 
Published: March 2010

Abstract
Rainbow trout (Salmo gairdneri) and lake whitefish (Coregonus clupeaformis) were exposed for 72 d to 109Cd in pelletized commercial trout food or in the water in a continuous-flow water exposure system. Blood, gill, gut, liver, kidney, muscle, skin, feces and gut contents were sampled from 40 fish in each group during the exposure phase and from 20 fish in each group during the subsequent 56-d depuration period. Gill accumulated the highest cadmium concentrations. After 56 d of depuration, most of the cadmium in food-exposed fish of both species was in the kidney, gut and liver, but water-exposed fish retained most of the cadmium in gill and kidney. Whole-body concentration factors (L/kg wet weight tissue) after 72 d of exposure for water-exposed fish were 55 for rainbow trout and 42 for whitefish. Whole-body bioconcentration factors after 72 d of exposure for food-exposed fish were less than 1 (kg food/kg dry weight tissue). Both species accumulated significantly greater proportions of the cadmium dose from food than from water. The percentages of the cadmium dose accumulated after 72 d of water exposure were 0.15% for trout and 0.11% for whitefish, while for food exposure the values were 1.03% for trout and 1.01% for whitefish. A simple two-compartment kinetic model was fitted to the data. Equilibrium cadmium bioconcentration factors for aqueous exposure were estimated to be 161 for rainbow trout and 51 for lake whitefish. Biological half-times for depuration ranged from 24 to 63 d.
Acute colonization study of polychlorinated biphenyl-degrading pseudomonads in the mouse intestinal tract: Comparison of single and multiple exposures
Authors: George Susan E. , Kohan Michael J. , Claxton Larry D. , Walsh Debra B. 
Published: March 2010

Abstract
The coprophagic behavior of rodents has been used in a model examining the potential health effects of environmentally released microorganisms. Mutant polychlorinated biphenyl (PCB) degrading pseudomonads, isolated from a commercial product for PCB elimination, were used to evaluate the method. The PCB-degrading component of the product was composed of one Pseudomonas maltophilia and three Pseudomonas aeruginosa strains enhanced for PCB degradation through nitrosoguanidine mutagenesis. Multiple ingestions of the biodegraders were compared with a single exposure. The direct health effects monitored were changes in weight, appetite and overall appearance. The indirect health effects monitored included recovery of the organisms from intestinal contents as well as competition with and alteration of the normal intestinal flora. When animals received a single dose by gavage of 109 colony forming units of an individual Pseudomonas sp., none of the four dosed strains were detected 14 d after dosing when animals were housed in metabolism cages. The use of these metabolism cages, which had wire flooring, limited coprophagy. When animals were housed in conventional cages, which allowed coprophagy, two of the four PCB degraders tested were recovered (104/g intestine). The lactose-fermenting and total aerobic counts were unaffected when animals received a single dose of the biodegrader. In the multiple exposure model, P. maltophilia altered the lactose-fermenting population. The total aerobic counts differed significantly from values for control animals when the animals were exposed to P. aeruginosa strains BC16, BC17 and BC18. Obligately anaerobic gram-negative rod populations were affected in P. aeruginosa strain BC17-dosed animals. Strains BC16 and BC18 altered both the obligately anaerobic rod populations and total anaerobic counts.
Response of hydrilla (hydrilla ver ticillata(L.f.) royle) to diquat and a model of uptake under nonequilibrium conditions
Authors: Cassidy Kelly , Rodgers John H. 
Published: March 2010

AbstractResponse of the aquatic macrophyte hydrilla (Hydrilla verticillata (L.f.) Royle) to the herbicide diquat was measured by dissolved oxygen concentration in the surrounding water, chlorophyll a concentration in plant tissue and membrane permeability of hydrilla cells. Dissolved oxygen concentration was the most rapid and sensitive measure of response, followed by membrane permeability. Chlorophyll a was an inadequate measure of response because of high variability in measurements and slow response time. The lethal concentration of diquat in hydrilla tissue was approximately 600 μg/g dry weight. The uptake of diquat by hydrilla was modeled under nonequilibrium conditions and assuming exponential decay of diquat from the surrounding water. The modeled uptake depended on the rate of decay of diquat from the water column, the rate of uptake of diquat by hydrilla and the rate of depuration of diquat from hydrilla. The observed uptake closely matched the calibrated, predicted uptake.
Effect of dissolved organic matter from Canadian shield lakes on the bioavailability of 1,3,6,8-Tetrachlorodibenzo-p-dioxin to the amphipod Crangonyx laurentianus
Authors: Servos Mark R. , Muir Derek C. G. 
Published: March 2010

Abstract
The effect of dissolved organic matter (DOM) on the apparent solubility and bioavailability of 1,3,6,8-tetrachlorodibenzo-p-dioxin (1,3,6,8-TCDD) was examined in epilimnetic and sediment interstitial waters collected from the Canadian Shield lakes in the Experimental Lakes Area of Northwestern Ontario. DOM enhanced the apparent solubility of 1,3,6,8-TCDD by as much as three times over the reference DOM-free water (DOM &lt;0.24 mg/L). The percentage of 1,3,6,8-TCDD bound to DOM increased as the dissolved organic carbon (DOC) concentration increased. Uptake rate constants of 1,3,6,8-TCDD in Crangonyx laurentianus decreased in the presence of DOM. Only the 1,3,6,8-TCDD that was truly in solution was apparently available for uptake by biota. The quality or site of collection of the DOM was also an important factor. Sediment interstitial waters had a greater affinity for 1,3,6,8-TCDD than did epilimnetic waters, as indicated by the DOC partition coefficients. Although the DOM may enhance the apparent solubility of 1,3,6,8-TCDD, DOM also reduces the amount of 1,3,6,8-TCDD truly free in solution and therefore bioavailable. Solubility enhancement may, however, lead to greater dispersion of 1,3,6,8-TCDD and low-level exposure of biota as the 1,3,6,8-TCDD gradually desorbs from the TCDD-DOM complex.
An in situ river exposure vessel for bioaccumulation studies with juvenile fish
Authors: Jones Peter A. , Sloan Ronald J. 
Published: March 2010

Abstract
A large-volume, easily handled exposure vessel for juvenile fish for use in bioaccumulation studies of water-borne contaminants in larger rivers was designed and tested in the Hudson River in New York. The exposure vessel minimized stress to the fish and allowed representative contaminant accumulation during time-series subsampling and a long-term in situ exposure.
Acclimation-induced changes in toxicity and induction of metallothionein-like proteins in the fathead minnow following sublethal exposure to zinc
Authors: Hobson James F. , Birge Wesley J. 
Published: March 2010

Abstract
Experiments were conducted to determine if a correlation exists between acclimation-induced alterations in Zn toxicity and the concentration of metallothionein-like proteins (MTP) in a cyprinid fish. Populations of subadult fathead minnows, Pimephales promelas, were maintained in dechlorinated tap water and exposed to 0, 0.60 and 1.80 mg Zn/L for 35 d. Groups of animals (120 each) were removed from each acclimation population after 0, 7, 14, 21 and 35 d to conduct 96-h acute tests. Tolerance and resistance were monitored as changes in the 96-h LC50 and LT50 values, respectively. Tolerance increased a significant 28% above control values after 14 d of exposure to 0.60 mg Zn/L, but decreased significantly to 63 and 74% of control values following exposure to 1.80 mg Zn/L for 7 and 14 d (p &lt; 0.05). Acute toxicity values returned to control levels in both treatment groups after 21 d of exposure and remained stable to 35 d. The concentration of MTP was measured in the viscera (i.e., liver, spleen, intestine and pancreas) indirectly as the total Zn-binding capacity in MTP-containing fractions. MTP levels increased after 7, 14 and 21 d and plateaued to 35 d. Metal concentration in the MTP fraction reached a maximum of 31.6 μg Zn/g viscera, and following 28 d of exposure to 1.80 mg Zn/L concentrations declined to control levels after 7 d in diluent water. Whole-body residues of Zn reached steady state after 7 d of exposure to 0.60 mg Zn/L but continued to increase after 35 d of exposure to 1.80 mg Zn/L. Zn-acclimated animals were cross-resistant but not cross-tolerant to acute Cd challenge. There was no correlation of alterations in toxicity with observed changes in MTP concentration. Growth effects were observed at both acclimation exposure levels.
Stimulation of superoxide production by nitrofurantoin, p-nitrobenzoic acid and m-dinitrobenzene in hepatic microsomes of three species of freshwater fish
Authors: Washburn Peter C. , Di Giulio Richard T. 
Published: March 2010

Abstract
The importance of nitroaromatic compounds as aquatic contaminants and the association of superoxide (O−2) mediated toxicity with the mammalian metabolism of a number of these compounds has led our laboratory to conduct an in vitro investigation of nitroaromatic-stimulated production by freshwater fish. Utilizing cytochrome c reduction and cyanide-insensitive oxygen consumption assays for O−2, channel catfish (Ictalurus punctatus), largemouth bass (Micropterus salmoides) and rainbow trout (Salmo gairdneri) hepatic microsomes were exposed to nitrofurantoin (NF), p-nitrobenzoic acid (PNBA) and m-dinitrobenzene (MDNB). NF and PNBA were chosen for study as model nitroaromatic compounds, known to stimulate microsomal O−2 generation in mammals; MDNB was chosen because it frequently contaminates aquatic systems. The results demonstrated that each of the three nitroaromatics is capable of significantly enhancing superoxide dismutase (SOD) inhibitable cytochrome c reduction and oxygen consumption, providing specific evidence of stimulated microsomal production of O−2 by the fish species examined. The results also indicated chemical- and species-specific differences in stimulated O−2 production. In both assay systems, enhancement by NF exceeded that produced by MDNB and, more pronouncedly, PNBA. Furthermore, although similar responses to all nitroaromatics were observed in microsomes isolated from catfish and bass, the assays employing trout microsomes demonstrated the greatest enhancement in NF and MDNB exposures. These findings suggest that the stimulation of O−2 production may be an important mode of action for these common aquatic pollutants that merits further ecotoxicological assessment.
Mutagenic potential of runoff water from soils amended with three hazardous industrial wastes
Authors: Davol P. , Donnelly K. C. , Brown K. W. , Thomas J. C. , Estiri M. , Jones D. H. 
Published: March 2010

Abstract
The bacterial mutagenicity of runoff water from soils contaminated with hazardous industrial waste was monitored for a three-year period using Salmonella typhimurium strain TA98 with and without metabolic activation. The wastes included a wood-preserving waste, a combined American Petroleum Institute (API) separator/slop oil emulsion sludge and a storm-water runoff impoundment waste. The wastes were applied to a Weswood silt loam soil (Fluventic Ustochrept) and a Bastrop clay loam soil (Udic Paleustalf) at a rate of 3.1% (wt./wt.) for the wood-preserving waste and of 4.5% for the two refinery wastes.
The results indicate that the runoff water from each of the waste-amended soils contained mutagenic constituents. The maximum specific activity was 783 net revertants per milligram residue, which was induced by the runoff water collected from the storm-water runoff impoundment-amended Weswood soil 360 d after application and assayed with metabolic activation. This sample also yielded the maximum weighted activity of 6,554 revertants per liter of runoff water. The mutagenic activities of the runoff water from all waste-amended soils displayed significant increases through 360 d after application and, in most cases, significant decreases in the samples collected approximately three years after application. The mutagenic activities of the runoff water from the Weswood soil were consistently greater than the activities of the runoff water from the Bastrop soil. These results indicate that three years or more may be required for the mutagenic activity of runoff water to return to background level, and that different soils will differ in their capacities to retain mutagenic chemicals during rainfall events.
Adaptation to a quaternary ammonium surfactant in aquatic sediment microcosms
Authors: Shimp Robert J. 
Published: March 2010

Abstract
Adaptation by natural microbial communities may be operationally defined as an increase in the biodegradation rate of a chemical as a result of exposure to the material. The comparative adaptation of sediment-associated and water microbial communities to the sorptive cationic surfactant dodecyltrimethylammonium chloride (C12-TMAC) was studied in continuous-flow, settled-sediment microcosms. In microcosms initially exposed to an input concentration of 0.1 mg/L C12-TMAC, biodegradation activity in the water column increased 20-fold after approximately 10 to 15 d. As input concentrations of C12-TMAC entering the microcosm were increased, water column biodegradation activity also increased, even though measured water column concentrations remained relatively constant, due to biodegradation and/or adsorption. When C12-TMAC input was reduced to zero, microbial activity returned to control levels. Sediment biodegradative activity was unaffected by input concentrations of C12-TMAC below 0.5 mg/L. When the input concentration was increased to 10 mg/L, biodegradative activity increased by at least 10-fold. Once adaptation had occurred in the sediments, the process was relatively unaffected by reductions in the concentration of C12-TMAC entering the microcosms. Thus, relative to processes in the water column, the presence of sediments can influence both the onset of adaptation and its persistence.
Evaluation of bioassays for designing sediment cleanup strategies at a wood treatment site
Authors: Athey Leslie A. , Thomas John M. , Miller William E. , Word Jack Q. 
Published: March 2010

Abstract
Standard bioassays were studied to evaluate their value in guiding remedial action decisions at sites contaminated with wood treatment operation wastes. The toxicities of sediment, sediment elutriate and whole water samples collected from a creek adjacent to a wood treatment site in Mississippi were estimated using six bioassays and compared with estimated concentrations of creosote and related materials obtained from the same samples by infrared spectroscopy. Of the bioassays, Daphnia and Microtox were most sensitive to the contaminants from the wood treatment operation. Based on an analysis of these samples, chemical analysis alone is insufficient to guide cleanup decisions, but bioassays alone can provide usable guidance, especially if more than one contaminant is present.