ISSN:0730-7268    

DOI:10.1002/etc.5620090401

出版商:Wiley Periodicals, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractThe enhanced biotransformation of vinyl chloride (VC) under anaerobic conditions was studied using static microcosms and a flow‐through column packed with soil from a study site. Vinyl chloride was found to be resistant to transformation in the static microcosms in five months of incubation; however, 89% of the vinyl chloride that was dissolved in the water was transformed when the microbiota in the columns was stimulated with a mixture of nutrients. In the presence of nutrients such as methane, methanol, ammonium phosphate and phenol, the main products of biotransformation were nonchlorinated organics such as methane and ethylene. Sodium acetate, added to the water and soil, did not enhance the biotransformation of VC because acetate‐utilizing bacteria were not found at the study site and none developed in soil sample after the 21 d allowed for adaptation. Four biodegradation mechanisms of vinyl chloride under anaerobic conditions were recognized in this study: (a) reductive dechlorination to ethylene; (b) mineralization to methane; (c) formation of chloromethane, probably followed by methane formation; and (d) bio‐oxidation to CO2, where acetate and citrate were added. A pseudo‐first‐order rate constant of 1.01 × 10−3months−1and at1/2of 57.2 years were calculated for the disappearance of vinyl chloride in soil and water microcosms under anaerobic conditions, without

ISSN:0730-7268    

DOI:10.1002/etc.5620090402

出版商:Wiley Periodicals, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractThe 14‐d LC50 toxicity to the guppy of tenO,O‐dimethylO‐phenyl phosphorothionate pesticides is analyzed with respect to linear two‐parameter quantitative structure‐activity relationship (QSAR) models containing partitioning and reactivity descriptors. The use of quantum chemical parameters within the modified neglect of diatomic overlap (MNDO) scheme leads to QSAR models with correlation coefficients up to 0.95 that are based solely on theoretically derived descriptors. Furthermore, the results show that quantum chemical descriptors have a particular value in modeling chemical reactivity within homologous series of

ISSN:0730-7268    

DOI:10.1002/etc.5620090403

出版商:Wiley Periodicals, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractThis in situ study is focusing on the distribution, biotransformation and flux of 19 polycyclic aromatic hydrocarbons (PAH19) in the food chain seston‐blue mussel (Mytilus edulisL.)‐common eider duck (Somateria mollissiimaL.) as well as the distribution in the gallbladder, liver, adipose tissue and egg of the duck. All samples were collected within the open northern Baltic proper coastal areas. Analyses were carried out by gas chromatography/mass spectrometry with electron impact (GC‐MSEI) and negative ion chemical ionization (GC‐MSNICI). With a multivariate statistical method (SIMCA) a significant change in the PAH composition through the food chain was found. This change probably depends on an increasing metabolic activity with increasing trophic level, due to a selective biotransformation capacity for different PAHs. Decreasing PAH concentrations with increasing trophic level were found. The PAH concentrations in the different eider duck organs were: gallbladder>adipose tissue ≥ liver. The theoretical inhalation of air‐dispersed PAHs was of no significance compared to the exposure from food. The relatively high theoretical PAH flux through the food chain did not result in increasing concentrations with increasing trophic level, which indicates that PAHs are biotransformed quite fast. However, many intermediate metabolites of PAHs have a mutagenic and carcinogenic potential, which makes it important to observe these compounds when assessing ecotoxicolo

ISSN:0730-7268    

DOI:10.1002/etc.5620090404

出版商:Wiley Periodicals, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractThe objective of this study was to monitor the mutagenic potential of leachate from soils amended with municipal sewage sludge. TheSalmonella/microsome assay was employed to monitor the mutagenicity of the organic extract of leachate collected from sludge‐amended lysimeters containing undisturbed monoliths of Weswood silty clay (Fluventic Ustochrept) and Padina loamy sand (Grossarenic Paleustalf) soils. The sludge was applied to 18 barrel‐sized lysimeters, while 6 unamended lysimeters served as controls. The leachate was concentrated on a combined XAD‐2/XAD‐7 resin, and the adsorbed organics were eluted with acetone. The leachate extracts were tested in the standard plate incorporation assay using strain TA98 with and without metabolic activation. Nine of 26 leachate extracts induced a positive response in the bioassay. The maximum specific activity was 207 net revertants per 10 mg induced without metabolic activation in the Weswood soil at the highest application rate (150 Mg/ha). The results suggest that land application of municipal sewage should be carefully managed to prevent leaching of mutagens into groun

ISSN:0730-7268    

DOI:10.1002/etc.5620090405

出版商:Wiley Periodicals, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractMobility and persistence of commercial formulations of alachlor, metolachlor and isazofos were studied under two moisture regimes using 75 × 15 cm field lysimeters. Formulated atrazine was also applied to each lysimeter for reference purposes. Alachlor‐ and metolachlor‐treated lysimeters were packed with Plainfield sand, while Honeywood silt loam was used to pack isazofos‐treated lysimeters. Effluent was monitored for each chemical, and selected cores were sectioned (7 × 10 cm) and analyzed to determine mobility profiles and persistence at weeks 1, 2, 4, 8, 12 and 21. The 50% disappearance times (DT50) for alachlor, atrazine, isazofos and metolachlor were:alachlor; in Honeywood silt loam: Des‐A

ISSN:0730-7268    

DOI:10.1002/etc.5620090406

出版商:Wiley Periodicals, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractTo control toxic pollutants in effluents, it is necessary first to identify the toxicants. To make identification possible it is desirable to isolate the toxicants from their effluent matrices and concentrate them. This article describes a simple method in which the nonpolar organic fraction of an effluent is concentrated into methanol. The methanol solution can be directly analyzed by GC‐MS and can also be diluted and tested for toxicity. Results from the laboratory where this method is being used show that in cases where the effluent toxicants were nonpolar organic compounds 60% of the effluent's toxicity was recovered in the methanol concentrate and the toxicants were identified by GC

ISSN:0730-7268    

DOI:10.1002/etc.5620090407

出版商:Wiley Periodicals, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractAdsorption distribution ratios for [14C]‐dodecyltrimethylammonium chloride (C12TMAC) to sediment have been measured at realistic environmental concentrations. As observed by investigators of hydrophobic organic and metal sorption, the distribution ratio was found to be inversely related to the sediment concentration. The value of the distribution ratios varied from 440 L/kg at a sediment concentration of 248,000 mg/L up to 251,000 L/kg at a sediment concentration of 230 mg/L. Data can be fit to Freundlich isotherms with slopes ≤1. Data are consistent with an ion‐exchange mech

ISSN:0730-7268    

DOI:10.1002/etc.5620090408

出版商:Wiley Periodicals, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractResults have been presented on the development of a structure‐activity relationship for biodegradation using a group contribution approach. Using this approach, reported results of the kinetic rate constant agree within 20% with the predicted values. Additional compound studies are essential to further extend the methodolog

ISSN:0730-7268    

DOI:10.1002/etc.5620090409

出版商:Wiley Periodicals, Inc.    

年代:1990

数据来源: WILEY

摘要:

AbstractThree experiments were conducted to determine if reduced consumption of foods with elevated Al levels by black ducks (Anas rubripes) was due to taste aversion, conditioned taste aversion or malaise. Black ducks preferred a diet with 1,000 ppm Al over a control diet but ate less of a diet with 5,000 ppm Al. Prior experience with the high Al diet enhanced preference for the control diet. Changes in body weight and food consumption through time suggested that aversion to the high Al diet was a conditioned response to mild malaise.

ISSN:0730-7268    

DOI:10.1002/etc.5620090410

出版商:Wiley Periodicals, Inc.    

年代:1990

数据来源: WILEY