摘要:

AbstractThe concentrations of 1,2‐dichloroethane due to a spill into the Rhine River are calculated with a one‐dimensional dispersion‐advection model. Particular attention was given to the hydrologic variety along the river by a careful selection and estimation of the governing parameters. The calculated results are in good agreement with observed concentrations for three sites of measurement at the middle Rhine. At two neighboring sites in the lower Rhine there is a striking discrepancy. Using Monte‐Carlo simulations, it can be shown that uncertainties of the input parameters cannot explain the overestimated concentrations. Possibly, the elimination is increased by shallow water zones in the lowe

ISSN:0730-7268    

DOI:10.1002/etc.5620100901

出版商:Wiley Periodicals, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractAqueous concentration time series of the herbicide atrazine and its phytotoxic metabolite desethylatrazine obtained from 1981 to September 1990 in the Thames, Grand, and Saugeen rivers draining agricultural southwestern Ontario were analyzed to ascertain temporal trend, seasonal variation, and mass‐discharge patterns Substantial year‐to‐year changes were evident. Data suggest that the greatest applications of the decade might have occurred in 1984; however, in 1985 significant decreases in levels were observed at all three sites, apparently due to an abrupt shift away from corn cultivation. Mass‐discharge estimates generally parallel the concentration trends but also reflect hydrometeorologic trends. In 1984 for the Thames basin, extremely high concentrations together with high flows combined to export about 13 tonnes (t) atrazine plus metabolite, the largest single annual loss to surface‐water systems observed over the decade. Driven by the annual spring‐summer application cycle, aqueous concentrations surge in late May to reach annual peaks in late June and early July Despite the declining levels of recent years, Thames River data suggest that the probability of exceeding the Canadian water quality guideline of 2 μg/L for protection of aquatic life, primarily algae and vascular plants, may yet approach 65%. The greatest risks to susceptible species are likely associated with large summer storm runoff in areas of high soil to surface water transfer potential. Herbicide usage in general continues in large quantities, and continued surveillance appears warranted. Further research is required to ascertain the ultimate fate of these compounds in end receiving waters such as th

ISSN:0730-7268    

DOI:10.1002/etc.5620100902

出版商:Wiley Periodicals, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractUsing a grid pattern, a total of 50 soil borings (DCT 1 through DCT 50) were collected from an abandoned chemical manufacturing facility. Split samples were obtained from six cores collected from a centralized location near a former wastewater lagoon. An additional sample from the 2.1‐ to 2.4‐m depth of core DCT 20 was obtained as representative of the waste present on site. Three subsamples from each of the six cores or a total of 18 samples were sequentially extracted with methylene chloride and methanol for testing in mutagenicity and acute toxicity assays. A separate batch extraction with water was conducted and evaluated, using both chemical and biological test methods. The maximum mutagenic response was 3,237 net revertants induced with metabolic activation by 1 mg of the methanol extract of the 0‐ to 0.6‐m depth at sampling location DCT 32. The water extract of the 0‐ to 0.6‐m depth at sampling location DCT 32 induced 737 net revertants per mg. At sampling location DCT 24, the water extract induced 0.74, 1.32, and 2.5 toxic units in the Microtox® assay and 935, 69, and 39 net revertants per mg in the mutagenicity assay at the 0‐ to 0.3‐, 1.2‐ to 1.4‐, and 2.1‐ to 2.4‐m depths, respectively. The chemical analysis of the samples from location DCT 24 indicated that the concentration of 2,3,6‐trichlorobenzene acetic acid ranged from 16 ppm in the 0‐ to 0.3‐m depth and to 0.95 ppm and below the detection limits at the 1.2‐ to 1.4‐ and 2.1‐ to 2.4‐m depths. The methanol extract of the soil from the 0‐ to 0.3‐m depth induced 19.2 toxic units in the acute toxicity assay and 1,467 net revertants in the mutagenicity assay. These results suggest that the most accurate site assessment is obtained when a water extract is evaluated to measure leaching potential and a solvent extract is evaluated to determine the relative total hazard of the sample. In addition, the combined use of chemical analysis, mutagenicity, and acute toxicity bioassays provides more accurate inform

ISSN:0730-7268    

DOI:10.1002/etc.5620100903

出版商:Wiley Periodicals, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractEight hydroxylated carbazoles and dibenzothiophenes were tested for mutagenic activity using the CHO/HGPRT mutation assay for thioguanine resistance. All showed increased activity over carbazole and dibenzothiophene. Some of the hydroxycarbazoles showed slightly higher activity than the corresponding hydroxy‐dibenzothiophenes (71.4 ± 5.2 mutants/106survivors for 1‐hydroxycarbazoles compared to 21.8 ± 6.1 mutants/106survivors for 4‐hydroxydibenzothiophene at 5 μg/ml, and 32.8 ± 3.3 mutants/106survivors at 5 μg/ml for 4‐hydroxycarbazole as compared to 16.4 ± 0.9 mutants/106survivors for 1‐hydroxydibenzothiophene at 5 μg/ml). The most mutagenic compound was 1‐hydroxycarbazole, which also exhibited cytotoxicity. The relative order of mutagenic activity of the hydroxycarbazoles was 1 ≥ 4>2 = 3>carbazole, and the relative activity of the hydroxydibenzothiophenes was 2 ≥ 3>1 = 4>dibenzothiophene. Overall, the mutagenic activity of the hydroxycarbazoles and hydroxydibenzothiophenes was dependent on the structural positio

ISSN:0730-7268    

DOI:10.1002/etc.5620100904

出版商:Wiley Periodicals, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractAmerican kestrels (Falco sparverius), eastern screech‐owls (Otus asio), and northern bobwhites (Colinus virginianus) were given single acute oral doses of four widely diverse anticholinesterase pesticides: EPN, fenthion, carbofuran, and monocrotophos. LD50s, based on birds that died within 5 d of dosage, were computed for each chemical in each species. Sex differences in the sensitivity of northern bobwhites in reproductive condition were examined. American kestrels were highly sensitive to all chemicals tested (LD50s 0.6–4.0 mg/kg). Eastern screech‐owls were highly tolerant to EPN (LD50 274 mg/kg) but sensitive to the remaining chemicals (LD50s 1.5–3.9 mg/kg). Northern bobwhites were highly sensitive to monocrotophos (LD50 0.8 mg/kg) and less sensitive to the remaining chemicals (LD50s 4.6–31 mg/kg). Female bobwhites (LD50 3.1 mg/kg) were more sensitive to fenthion than males (LD50 7.0 mg/kg). Mean percent depression of brain cholinesterase (ChE) of birds that died on the day of dosing exceeded 65% for all chemicals in all species. The response of one species to a given pesticide should not be used to predict the sensitivity of other species to the same pesticide. The need for research on several topics is

ISSN:0730-7268    

DOI:10.1002/etc.5620100905

出版商:Wiley Periodicals, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractA mammalian in vitro system was used to evaluate the genotoxic potential of two complex environmental samples. Sister chromatid exchanges (SCEs) were measured in Chinese hamster V79 lung fibroblast cells, following exposure to whole extracts of sediments collected from a highly contaminated harbor — Black Rock Harbor, Connecticut (BRH) — and from a reference site — central Long Island Sound (CLIS). Characterization of BRH sediment by analysis of prepared chemical extracts revealed high concentrations of polyaromatic hydrocarbons, anthraquinones, carbazoles, and several inorganic substances that are genotoxic and capable of inducing SCEs. The CLIS sediment, although cleaner than BRH sediment, does contain low levels of similar contaminants. For instance, BRH sediment contains 3.16 μg/g of the polynuclear aromatic hydrocarbon benzo[a]pyrene (BP), whereas CLIS sediment contains only 0.807 μg/g BP. Sediments were extracted with organic solvents and redissolved in dimethyl sulfoxide (DMSO) for culture exposure. Following exposure, extract‐treated cells were evaluated for increased frequencies of SCEs. All assays were performed with and without exogenous S9 activation. Positive responses were observed only in the presence of exogenous S9 metabolism. Results indicated a concentration‐dependent increase in SCEs in cells exposed to whole BRH sediment extracts and a smaller but significant increase in SCEs in cells exposed to whole CLIS sediment extracts. Four times as much CLIS material (0.13 g extracted sediment [dry wt.]/ml of exposure media) was needed to induce a significant doubling in SCEs, compared to BRH material, in which only 0.03 g extracted sediment (dry wt.)/ml of exposure media was needed. These findings imply that this short‐term in vitro bioassay can be used to evaluate the genotoxic potential of complex environmental samples such as contaminated mar

ISSN:0730-7268    

DOI:10.1002/etc.5620100906

出版商:Wiley Periodicals, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractAcetylenic and allylic alcohols have been reported to be 20 to 5,000 times more acutely toxic to fathead minnows (Pimephales promelas) than would be expected from a narcosis‐based mechanism of action. The greater‐than‐expected toxicity of these alcohols has been proposed to be a result of metabolic activation to the corresponding reactive α,β‐unsaturated aldehydes or allene derivatives. Using purified horse liver and rainbow trout (Oncorhynchus mykiss) hepatic cytosol alcohol dehydrogenase (ADH) preparations, the propensity of a series of acetylenic and allylic alcohols to inhibit enzyme activity, in both the presence and the absence of reduced glutathione, was ascertained. Those alcohols classified as reactive toxicants in acute toxicity tests were generally effective inhibitors of ADH activity, whereas those alcohols classified as narcotics were generally ineffective inhibitors. The results from this study suggest that (a) acetylenic and allylic alcohols may be metabolically activated to reactive species and (b) to compare and ultimately predict the toxicity of these unsaturated alcohols, their rates of metabolic activation and the reactivity of the subsequently produced aldehydes must be q

ISSN:0730-7268    

DOI:10.1002/etc.5620100907

出版商:Wiley Periodicals, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractNatural populations of bacteria in water samples from the lower Rhine River were tested for their sensitivity to selected toxicants. Bacterial growth, measured as [3H‐methyl] thymidine incorporation, was affected by additions of 5 μg Cu L−1; these concentrations were similar to the copper concentrations found in the river. Concentrates of the organic fraction from river water, obtained via XAD‐columns, affected thymidine incorporation in samples of river water when added in concentrations corresponding to ambient levels. The exoenzymatic activities of phosphatase and protease decreased systematically at concentrations higher than 5 μg Cu L−1. Potassium dichromate (K2Cr2O7) at a concentration of approximately 3 mg L−1and a detergent tetrapropylbenzene sulfonate (TPBS) at a concentration of 5 mg L−1had detectable effects on microbial activity. Atrazine affected the growth rate but not the enzymatic activity of bacterial populations when this herbicide was added in concentrations of 50 to 200 μg L−1. Thymidine incorporation was more sensitive to all test compounds than the enzymatic activities. It is concluded that the present pollution levels, although decreased, are still likely to affect microbial proces

ISSN:0730-7268    

DOI:10.1002/etc.5620100908

出版商:Wiley Periodicals, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractAmmonia is a widespread contaminant that occurs in municipal wastewaters, industrial wastewaters, and agricultural wastes. Most ammonia toxicity studies deal with species of fish and macroinvertebrates, but very little information is available on ammonia phytotoxicity. The objectives of this study were to compare ammonia toxicity by using static and renewal methods and to compare phytotoxicity tests by using the vascular plants common duckweed and rice. Un‐ionized ammonia‐N at the rate of 8.85 mg/L inhibited rice seedling growth by 27%, using the renewal method, whereas the same amount caused insignificant effects on rice growth, using the static method. Ammonia‐N at up to 8.85 mg/L did not inhibit duckweed growth, using the static method. By using the renewal method, un‐ionized ammonia‐N at concentrations greater than 3.0 mg/L depressed duckweed growth noticeably (20% or more). The increased ammonia concentration inhibited duckweed growth correspondingly, producing a linear relation for the concentration‐inhibition effect. An un‐ionized ammonia‐N concentration of 7.16 mg/L was calculated to cause 50% duckweed growth inhibition (IC50), and 95% confidence limits ranged from 6.

ISSN:0730-7268    

DOI:10.1002/etc.5620100909

出版商:Wiley Periodicals, Inc.    

年代:1991

数据来源: WILEY

摘要:

AbstractThis study was conducted to explore the role of the mixed‐function oxidase (MFO) detoxication system in the “biochemical acclimatization” or adaptation of gulls to anthropic environments. In three different populations of black‐headed gull (Larus ridibundus) feeding in a lagoon, in municipal and industrial landfills, MFO microsomal hepatic activities (aldrin epoxidase, 7‐ethoxyresorufin‐O‐deethylase, NADPH‐cytochrome c reductase, NADH‐cytochrome c reductase, and NADH‐ferricyanide reductase), microsomal α‐naphthylacetate esterase activity, cytochrome P‐450 forms, and chlorinated hydrocarbon residues were determined. Induction tests and in vitro comparative kinetics studies were completed between the different populations of gulls. The detoxicant activities of the MFO system were much higher in the landfill gulls, especially those of the industrial landfill, than in lagoon gulls. Lineweaver‐Burk plots for aldrin epoxidase show an apparentKmfour to five times lower in the gulls of the industrial landfill than in the other two populations. The origin of the potentiated detoxication activities in landfill gulls is investigated and the hypotheses of biochemical acclimatization and geneti

ISSN:0730-7268    

DOI:10.1002/etc.5620100910

出版商:Wiley Periodicals, Inc.    

年代:1991

数据来源: WILEY