ISSN:0730-7268    

DOI:10.1002/etc.5620130701

出版商:Wiley Periodicals, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractSteroid hydroxylase activities were characterized inDaphnia magnaand evaluated for potential use as biomarkers of xenobiotic exposure. Microsomes prepared fromDaphma magnagenerated a single NADPH‐dependent metabolite of [14C]testosterone. However, intact daphnids excreted at least 10 polar metabolites of [l4C]testosterone into the test medium. Six of these metabolites were identified as 2α‐, 16β‐, 6β‐, 6α‐, 7α‐, and 15α‐[14C]hydroxytestosterone. The unidentified metabolites are also presumed to be hydroxylated products of testosterone, based on their relative migrations during TLC. The inefficient metabolism of [14C]testosterone during the in vitro microsomal incubations may have been due to the release of P450 inhibitors during microsome preparation. Exposure of daphnids to the P450 modulators phenobarbital, β‐naphthoflavone, piperonyl butoxide, and malathion differentially inhibited the steroid hydroxylase activities. Results from this study indicate thatDaphma magnaexpresses several P450 enzymes and that these enzymes are differentially modulated by xenobiotic exposure. Steroid hydroxylase activities may serve not only as a biomarker of toxicant exposure, but also as a predictor of toxicant effects involving perturbations of stero

ISSN:0730-7268    

DOI:10.1002/etc.5620130702

出版商:Wiley Periodicals, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractDNA, isolated from the blood cells of bluegill sunfish (Lepomis macrochirus) exposed in the lab to bedded sediment collected from a site contaminated with genotoxic compounds (i e, PAHs, PCBs, and heavy metals), was examined for strand breakage by agarose gel electrophoresis Before electrophoresis the blood cells were embedded in agarose plugs and incubated with proteinase After electrophoresis under both neutral (pH 7) or alkaline (pH 12) conditions, the median molecular length (MML) of the DNA distributed in the gel was determined These quantitative measures were used to estimate the difference in the number of double and single strand breaks between DNA preparations Both types of strand breakage were found to be greater in fish exposed to sediment contaminated with genotoxic compounds as compared to nonexposed fish A statistically significant correlation was demonstrated between the MML value obtained by the electrophoretic assay reported here and theFvalue (measure of DNA double strandedness) obtained by the alkaline unwinding assay

ISSN:0730-7268    

DOI:10.1002/etc.5620130703

出版商:Wiley Periodicals, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractPurple sea urchin(Strongylocentrotus purpuratus)gametes and embryos were exposed to three known mutagenic chemicals (phenol, benzidine, and pentachlorophenol) over concentration ranges bracketing the effect levels for fertilization success Normal development and cytogenetic effects (anaphase aberrations) were assessed after the cultures were allowed to develop for 48 h Using radiolabeled chemicals, we also characterized concentrations in the test water as well as doses in the embryos following 2 and 48 h exposures We observed dose responses for all chemicals and all responses, except for phenol, which showed no significant effect on development Fertilization success was never the most sensitive end point Anaphase aberrations were the most sensitive response for phenol, with an LOEC of 2 5 mg/L exposure concentration Anaphase aberrations and development were equivalent in sensitivity for benzidine within the tested dose range, and an LOEC of<0 1 mg/L was observed Development was the most sensitive response for pentachlorophenol (LOEC 1 mg/L) The LOEC values for this study were generally lower than comparable data for aquatic life or human health protection We conclude that genotoxicity and development evaluations should be included in environmental management applications and that tests developed primarily for human health protection do not reliably predict the effects of toxic substances on aquatic life

ISSN:0730-7268    

DOI:10.1002/etc.5620130704

出版商:Wiley Periodicals, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractSome proteins in organisms exposed to chemicals in stressful amounts or toxic concentrations show increased expression, others show decreased expression These inducible and repressible proteins together potentially provide qualitative and quantitative diagnoses of components in complex mixtures of chemicals We examined sets of proteins synthesized byDaphmamagnaafter exposure to mixtures of a catiomc polyamide epichlorhydrim adduct (Kymene) and a combined assortment of water extractable substances from chemi thermal mechanical pulp (CTMP) in lab water Proteins were identified, after extracting fromDaphma magna, by gel filtration and silver staining, or by radiolabelmg and then gel separation Patterns of proteins induced by Kymene® and by CTMP extracts were distinguishable in lab water, but there was interaction between them The method of identifying and quantifying Kymene, however, was successful using lab simulations of mixtures The method was tested using wastewater samples from a paper manufacturing plant Kymene could be detected against variable levels and types of additional substances But, again, there was interference, perhaps due to Kymene binding to other anionic polymers sometimes present in the samples Interpretations from analyses of protein expression were consistent with results from sublethalCeriodaphnia dubiaassay

ISSN:0730-7268    

DOI:10.1002/etc.5620130705

出版商:Wiley Periodicals, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractThe toxic effects of pollutants on the mineralization of 2 μg/L [U‐14C]‐4‐chlorophenol and benzoate were studied in microcosms with methanogenic sediment from a little harbor in the Rhine River In contrast with studies using a high sub‐strate concentration, no lag time was observed and the half‐lives for 4‐chlorophenol and benzoate were 1.6 and 0.55 h, respectively The effect of increasing additions of benzene, chloroform, 1,2‐dichloroethane, pentachlorophenol, and zinc on each mineralization reaction was measured. Toxicity data were fitted with a logistic dose‐effect curve. The IC10 is defined as the concentration of a toxicant inhibiting the mineralization rate for 10% The IC10 concentrations of benzene, chloroform, 1,2‐dichloroethane, pentachlorophenol, and zinc on the benzoate mineralization were 150, 0 04, 71, 6, and 842 mg/kg sediment dry weight, respectively. This latter value includes the background concentration of 800 mg Zn/kg sediment The mineralization of 4‐chlorophenol and benzoate showed similarities in the sensitivity to these toxicants. 4‐Chlorophenol can be degraded via benzoate, which might explain the similarities in sensitivity of both mineralization reactions. Chloroform proved to be extremely toxic to anaerobic mineralization reactions, which might be attributed to the formation of very toxic and reactive intermediates formed during the slow anaerobic degradation of the chloroform in anaerobic sediments Sediment quality criteria derived solely from standard toxicity tests using aerobic organisms may lead to complete inhibition of several important microbial processes

ISSN:0730-7268    

DOI:10.1002/etc.5620130706

出版商:Wiley Periodicals, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractSilicone polymers (polydimethylsiloxanes, or PDMS) are used in numerous personal care and household products, eventually enter wastewater treatment plants, and are later applied to the land as a component of sludge. The fate of silicones in soil is largely unknown, but this study shows that in a moist (0.2 MPa = 12% moisture) Londo sandy clay loam, 200 centi‐stoke (cs)14C‐labeled PDMS degraded slowly over six months to yield about 3% of applied14C as low‐molecular‐weight, water‐soluble products. When the soil was allowed to dry in one week from 12 to 3% moisture, the degradation rate was much more rapid, and after several days at 3 % moisture about half of the applied14C was water desorbable. HPLC‐GPC of tetrahydrofuran (THF) soil extracts showed that PDMS had been degraded to low‐molecular‐weight molecules of the general formula HO‐[Si(CH3)2O]n‐H. The range of moistures in this experiment was measured in a field of Londo sandy clay loam during the summer of 1992, indicating that PDMS should be unstable in the soil environment. Further work on the identification and biological degradation of these small

ISSN:0730-7268    

DOI:10.1002/etc.5620130707

出版商:Wiley Periodicals, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractThis work describes the use of volatile halocarbons in a pulp mill effluent, including chloroform, bromodichloro‐methane, and tri‐ and tetrachloroethylene, as tracers for the distribution and movements of effluent currents in a receiving water bay (Jackfish Bay) on the northern shore of Lake Superior. The results indicate the simplicity and usefulness of the technique and the significantly improved resolution of effluent plume delineation over the customary use of conductance profiles. Concentration patterns of the effluent volatiles suggest counterclockwise circulation of bay water that mixes with inflowing lake water at the eastern reach of the outer bay. The distribution of volatile contaminants is governed by the thermal regime of the receiving waters. During the summer months, the effluent plume wedges between the thermocline and epilimnion, mixing into the surface waters as the distance from the input source increases. In the fall, the colder effluent plume sinks into the hypolim‐nion and is confined by a bay/lake water‐density gradient. In the specific case at hand, the distribution patterns of chloroform and a brominated analog, bromodichloromethane, also suggest the release of chloroform from sediments in

ISSN:0730-7268    

DOI:10.1002/etc.5620130708

出版商:Wiley Periodicals, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractThis survey examined the relationship between environmental responses at pulp mill sites and the pulping process (kraft vs. sulphite/thermomechanical pulping), effluent treatment (primary vs. secondary treatment), and bleaching technology used by pulp mills. This manuscript is the first in a series of four; it reviews the location and operating characteristics of mills included in the survey and provides background information on water chemistry that is relevant to the other components of the survey. In addition, lab 7‐d toxicity tests of receiving water were conducted using fathead minnows (Pimephales prome‐las) and the cladoceranCenodaphma dubiawith water samples collected upstream (reference) and downstream (plume) of effluent discharges at 11 Canadian pulp and paper mills; these samples were collected at the same time as fish surveys were conducted. Survival of fathead minnow larvae was significantly reduced at four of the 11 downstream sites.Ceriodaphniareproduction was significantly higher at six of the 11 downstream sites and significantly lower at two downstream sites. There were no significant effects on fathead minnow larva growth or adultCenodaphmasurvival at any of the examined downstream sites. Negative effects in the toxicity tests were generally associated with the low dilution discharge of primary treated effluent with a previous history of acute toxicity. Fathead minnow andCenodaphniatests were generally correlated with historical data on benthic mac‐roinvertebrate community responses. Neither toxicity test predicted the physiological changes in wild fish that are presented in accompanying p

ISSN:0730-7268    

DOI:10.1002/etc.5620130709

出版商:Wiley Periodicals, Inc.    

年代:1994

数据来源: WILEY

摘要:

AbstractFish collected from the receiving areas of 12 Canadian pulp mills were examined, including sites receiving effluent from kraft mills using chlorine as well as sulfite mills. Field collections included sampling of receiving water for chemistry and toxicity testing, and sampling of local fish for organ weights, hepatic MFO (ethoxyresorufin‐O‐deethylase, EROD) activity, plasma steroid levels, and levels of liver dioxins. The main objectives of this study were to determine whether the discharge of effluent from pulp mills to sites other than Jackfish Bay was associated with physiological or biochemical disruptions in wild fish, whether there was any correlation between waste treatment and the presence of biological responses in wild fish, and whether there was any association between the use of chlorine as a bleaching agent and these responses. Although white sucker collected near bleached‐kraft mills exhibited the highest EROD induction and dioxin levels, elevated enzyme activity was observed in fish from sites that did not use chlorine, and depressions in plasma sex steroid levels was not correlated with the level of EROD activity. The absence of chlorine bleaching or the presence of secondary treatment did not eliminate responses in fish, including decreased circulating levels of sex steroids, decreased gonadal size, and increased liver size. This survey has shown that (a) induction of hepatic EROD enzymes and depressions of plasma sex steroid levels during gonadal growth are found downstream of several pulp mills; (b) these changes are seen at some mills without chlorine bleaching and at mills that have secondary treatment; (c) substantial dilutions of nontoxic effluent do not appear to remove these responses; (d) the dominant factor determining the presence or absence of responses appeared to be dilution level; and (e) lab toxicity tests on invertebrates, rainbow trout, and fathead minnows could not predict the presence of these responses in wild

ISSN:0730-7268    

DOI:10.1002/etc.5620130710

出版商:Wiley Periodicals, Inc.    

年代:1994

数据来源: WILEY