ISSN:0730-7268    

DOI:10.1002/etc.5620120401

出版商:Wiley Periodicals, Inc.    

年代:1993

数据来源: WILEY

ISSN:0730-7268    

DOI:10.1002/etc.5620120402

出版商:Wiley Periodicals, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractSeveral physical and chemical parameters of sediment extraction and fractionation of organic compounds that influence bioassay results were evaluated. Each parameter was evaluated with a photoluminescent bacterial bioassay (Microtoxr̀) as an end point. Three solvents (acetonitrile, acetone, and methanol) were studied for their ability to extract toxic organic components from marine sediments. Acetone extracted the most toxicity, with no difference between acetonitrile and methanol. Two methods of fractionating sediment extracts (silica‐gel‐column chromatography [SGCC] and acid‐base fractionation) were compared. SGCC was more useful because it resulted in a wider range of responses and was faster to perform than acid‐base fractionation. Microtox was used to rank four marine sediments with respect to toxicity and to determine if one chemical class (or fraction) was consistently more toxic among different sediments. With some caveats, Microtox results agreed with general chemical concentration trends and other bioassay results in distinguishing between contaminated and noncontaminated sediments. Although results indicated there was not a consistently most toxic fraction among sediments, there was a consistently least toxic fraction. The effect of sediment storage time on toxicity was also evaluated. Results indicated that the most stable chemical fraction (containing nonpolar hydrocarbons) did not change toxicologically for 30 weeks, whereas the more chemically active fraction (containing ketones, quinones, and carboxyls) changed as soon as

ISSN:0730-7268    

DOI:10.1002/etc.5620120403

出版商:Wiley Periodicals, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractThe individual and combined effects of atrazine and bifenthrin on lake communities were investigated in a two‐phased mesocosm study involving eighteen 5,500‐L tanks containing natural plankton assemblages and bluegill. The factorial‐designed experiment included three levels of bifenthrin (0, 39, and 287 ng L−1in phase 1 and 0, 125 and 3,150 ng L−1in phase two) cross‐classified with three levels of atrazine (0, 15, and 153 μg L−1in phase 1 and 0, 385, and 2, 167 μg L−1in phase 2), with duplicate replication. In phase 1, atrazine significantly reduced chlorophyll concentrations and turbidity (day 7) but had no significant impact on primary productivity or algal cell densities. Bifenthrin significantly reducedBosmina(days 7 and 14), cyclopoid copepodids (days 7 and 14), and copepod nauplii (day 14); however, bifenthrin increased rotifers at day 7. Bifenthrin also increased colonial green algae (day 7) and decreased turbidity (days 7 and 14). Only one fish mortality occurred during phase 1 of the study. In phase 2, atrazine resulted in significant reductions in primary productivity, chlorophyll, green algal colonies,Bosmina, and rotifers on day 7. Bifenthrin had a negative impact onBosmina, copepod nauplii, rotifers, primary productivity, chlorophyll, and green algal colonies. A 33% bluegill mortality was observed in tanks with an average maximum concentration of 3,150 ng L−1bifenthrin. The observed interaction effects indicated that when either compound was introduced at ecologically realistic levels, its effects were essentially masked if the other toxicant was present at high concentrations, and that the two pesticides did not

ISSN:0730-7268    

DOI:10.1002/etc.5620120404

出版商:Wiley Periodicals, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractDissolved hydrophobic chemicals can be concentrated with a passive, in situ concentration‐extraction sampler (PISCES), an inexpensive and easy‐to‐use device made from plumbing parts and polyethylene film. PISCES is intended to mimic the direct uptake of chemicals from water by fish without the complications of metabolism and the uncertainty of location of exposure. This report examines the practical application of PISCES to a problem in identifying the source of PCBs to the Black River (NY). PISCES were deployed on three occasions at stations throughout the length of the river. Solvent recovered from the PISCES was analyzed for polychlorinated biphenyl (PCB) congeners. Relative homolog abundances and absolute amount of recovered PCBs pointed to a particular river reach as a possible source. A fourth set of samples taken in the city of Carthage (NY) defined a plausible source. Conventional sampling methods would not have been effective in this situ

ISSN:0730-7268    

DOI:10.1002/etc.5620120405

出版商:Wiley Periodicals, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractThe present study was designed to derive appropriate ammonia standards for a freshwater, wooded stream on the Delmarva Peninsula (eastern shore of the United States) composed almost entirely of wastewater effluent for at least four months of the year. Representative species acute and chronic toxicity tests were performed at 20° (summer) and 12°C (winter) to obtain seasonal standards. Acute toxicity tests using fathead minnow andDaphnia magnasuggested that the site water had no effect on un‐ionized ammonia toxicity. However, resident species appeared to be relatively insensitive to acute exposures of un‐ionized ammonia. Warm‐water LC50s adjusted for pH = 8.0 and 20°C ranged between 1.02 and 2.73 mg/L for those tests in which an LC50 could be calculated. If acute no‐observed‐effect concentrations (NOECs) (approximately LC25) were used, bluegill was most sensitive (NOEC = 0.295 mg/L), followed byCrangonyx(amphipod) andMenidia(silverside). Warm‐water chronic testing indicated thatRana(leopard frog) was most sensitive, followed by bluegill and amphipod. Cold‐water acute tests yielded definitive LC50s between 0.53 (bluegill) and 1.91 mg/L (amphipod).Hyla crucifer(spring peeper) and juvenile bluegill were most sensitive in chronic cold‐water testing. Final acute values (FAVs) of 0.62 and 0.30 mg/L NH3were obtained for 20 and 12°C, respectively. The geometric mean of acute‐to‐chronic ratios (ACR) based on unionized ammonia were 7.2 and 5.7, for 20 and 12°C, respectively. The final chronic values (FCVs) or maximum 4‐d average concentrations at 20 and 12°C were 0.09 and 0.05 mg/L NH3, respectively. Un‐ionized ammonia acute toxicity to vertebrate freshwater species (fish and tadpoles) was inversely related to temperature, whereas invertebrates often exhibited the opposite trend. Chronic testing, however, suggested that most species were more sensitive to NH3at 20 than 12°C. This study suggests that the ACR developed by the U.S. Environmental Protection Agency (EPA) for warm‐water streams may be overly conservative for very small streams in which sp

ISSN:0730-7268    

DOI:10.1002/etc.5620120406

出版商:Wiley Periodicals, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractA multivariate characterization of the 136 tetra‐ to octa‐chloro‐substituted dibenzo‐p‐dioxins (PCDDs) and dibenzofurans (PCDFs) is reported. By principal component analysis (PCA) of a battery of physicochemical descriptors, an overview of similarities and differences between congener groups and substitution patterns is obtained. Available data for two biochemical end points, the induction of the enzymes aryl hydrocarbon hydroxylase (AHH) and ethoxy resorufinO‐deethylase (EROD), were used to construct quantitative structure‐activity relationships (QSARs) using partial least‐squares projections with latent variables (PLS). By applying the principles of statistical experimental design to the orthogonal scores from the PCA, a set of PCDD and PCDF congeners is proposed for further biological and toxicologi

ISSN:0730-7268    

DOI:10.1002/etc.5620120407

出版商:Wiley Periodicals, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractPresence of pesticide residues in animal tissues and inhibition of brain cholinesterase (ChE) activity are often used to document exposure of animals to organophosphorus and carbamate insecticides and determine if the animal's death resulted from exposure. Carcasses found during field studies can be several days old; therefore, it is important to determine how residue and ChE levels change over time after death. Objectives of this study were to determine pesticide residues in tissues and/or brain acetylcholinesterase (AChE) activity of northern bobwhite (Colinus virginianus) exposed to either sulprofos, methamidophos, or azinphos‐methyl, and the extent to which residue and AChE levels change with decomposition of carcasses under field conditions. Test compounds were administered orally by gavage and/or in the diet to northern bobwhite at previously determined sublethal and lethal exposure levels. Birds surviving the dose were sacrificed and placed in crop fields. Carcasses were recovered following 0‐, 24‐, 48‐, and in some cases 96‐h intervals and analyzed for residues. Brain AChE activity was also determined for birds exposed to sulprofos. Residues were detected in all exposed birds and varied with dose. Results indicate that pesticide residues and brain AChE levels were stable under field conditions at least up to 48 to 96 h follow

ISSN:0730-7268    

DOI:10.1002/etc.5620120408

出版商:Wiley Periodicals, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractAn in situ investigation of structural chromosomal damage in wild rodents from a site contaminated with Aroclor 1254 was undertaken to compare effects observed in nature to those documented in previous laboratory studies. Laboratory assays indicate that Aroclor 1254 does not cause structural damage to chromosomes. However, the many variables at work in actual waste‐site environments and receptor populations led us to question whether exposures under natural conditions could potentially lead to different results using the same assay systems. Individuals of three rodent species,Peromyscus leucopus, Sigmodon hispidus, andReithrodontomys fulvescens, were collected from the contaminated site and three matched, pristine reference sites. Standard somatic metaphase chromosome preparations from bone marrow were examined for chromosomes lesions. Comparisons were made between conspecifics from the Aroclor‐contaminated site and the reference sites. Significant increases in chromosome damage were not observed in animals from the Aroclor‐contaminated site, indicating agreement between laboratory assays and an in situ application of this assay s

ISSN:0730-7268    

DOI:10.1002/etc.5620120409

出版商:Wiley Periodicals, Inc.    

年代:1993

数据来源: WILEY

摘要:

AbstractOpen‐top chambers were used to determine the relationships between a hexachloroethane (HC) obscurant, zinc deposition, and foliar injury of tree species indigenous to military training facilities. Eight eastern U.S. tree species were exposed four times to three exposure regimens (0x, 1x, 2x) of the obscurant, measured as Zn, during the 1990 growing season. Plots received ambient or charcoal‐filtered air for comparison purposes. Black locust (Robinia pseudoacaciaL.) and black cherry (Prunus serotinaEhrh.) were the most sensitive species, exhibiting significant (p<0.05) necrotic leaf spot, chlorotic mottle, and marginal necrosis of leaves at the 2x levels throughout the season. Defoliation was also greater (p<0.05) in exposed vs. unexposed plots. Sugar maple (Acer saccharumMarsh.) injury was different among exposure regimens (p<0.05) only near the end of the season. Sweet gum (LiquidambarstyracifluaL.), eastern white pine (Pinus strobusL.), loblolly pine (Pinus taedaL.), and Virginia pine (Pinus virginianaMill.) were asymptomatic. Charcoal filtration did not affect severity of symptoms. Zinc deposition was positively correlated (p<0.05) with most of the symptoms on black locust and black cherry. The HC obscurant in the concentrations used in this study adversely affected these spec

ISSN:0730-7268    

DOI:10.1002/etc.5620120410

出版商:Wiley Periodicals, Inc.    

年代:1993

数据来源: WILEY