ISSN:0730-7268    

DOI:10.1002/etc.5620060301

出版商:Wiley Periodicals, Inc.    

年代:1987

数据来源: WILEY

摘要:

AbstractInfiltration of wastes containing creosote and pentachlorophenol from surface impoundments at an abandoned wood‐treatment facility near Pensacola, Florida, resulted in contamination of the underlying sand and gravel aquifer. Pond sludges and sediments near the source were contaminated with 2‐ to 5‐ring azaarenes having logKowvalues of from 2.0 to 5.6. However, the ground water contained only azaarenes and their oxygenated and methylated derivatives having logKowvalues of less than 3.5. These compounds also were present in coal tar‐contaminated ground water at a site near St. Louis Park, Minnesota.Laboratory anaerobic degradation studies and on‐site observations indicated that oxygenated azaarenes probably were biotransformation products of reactions mediated by indigenous microbial populations. MicrobialN‐methylation,C‐methylation andO‐methylation reactions are reported here for the first time. In the presence of nutrients and carbon sources such as acetate and propionate, all azaarenes studied were either partially or completely degraded. Evidence for the microbial degradation of azaarenes in ground water from anaerobic zones is presented. Oxygenated azaarenes were relatively more water‐soluble, mobile and persistent in hydrogeol

ISSN:0730-7268    

DOI:10.1002/etc.5620060302

出版商:Wiley Periodicals, Inc.    

年代:1987

数据来源: WILEY

摘要:

AbstractAvoidance of a blend of four metals (relative proportions: 1.00 copper, 0.54 chromium, 1.85 arsenic, 0.38 selenium) was determined in fathead minnows(Pimephales promelas)in a steepgradient, laminar‐flow chamber. Avoidance responses were determined seasonally during 12 months of laboratory observation for unexposed (control) and metals‐exposed fish. Unexposed fish avoided very low concentrations of the blend (29 μg/L total metals). Fish exposed to 98 μg/L total metals preferred elevated concentrations equal to three times the holding exposure concentration (294 μg/L total metals) after 3 months of exposure, mildly avoided concentrations five times the holding exposure concentration (490 μg/L total metals) after 6 months of exposure and were not responsive to concentrations approaching ten times the holding exposure level (980 μg/L total metals) after 9 months of exposure. Activity, as measured by movements per unit time in the avoidance tests, was not affected by long‐term exposure or duri

ISSN:0730-7268    

DOI:10.1002/etc.5620060303

出版商:Wiley Periodicals, Inc.    

年代:1987

数据来源: WILEY

摘要:

AbstractAvoidance of a blend of four metals (relative proportions: 1.00 copper, 0.54 chromium, 1.85 arsenic, 0.38 selenium) was determined in schools of fathead minnows(Pimephales promelas)in an artificial stream supplied with raw river water and in a natural stream. Control (unexposed) fish were tested in spring in the artificial stream and during summer in the artificial stream and a natural stream. Fish exposed continuously for 3 months to the blend of the four metals (98 μg/L total metals) in river water were tested during summer in the artificial and natural streams. Control fish avoided 71.1 and 34.3 μg/L total metals in the artificial stream in spring and summer, respectively, and 73.5 μg/L in the natural stream. Exposed fish did not respond to metals blends as high as 1,470 or 2,940 μg/L in the artificial and natural streams, respectively. Water hardness, turbidity and physical setting are implicated as possible causative factors in differences among control fish. Results are compared with those of previously reported laboratory studies and the effects of pollution observed in the New River, Virgi

ISSN:0730-7268    

DOI:10.1002/etc.5620060304

出版商:Wiley Periodicals, Inc.    

年代:1987

数据来源: WILEY

摘要:

AbstractDaphnia magnaStraus were exposed for 21 d to 0, 12, 27, 72, 158 and 811 μg/L di‐2‐ethylhexyl phthalate (DEHP). On days 7 and 21 of exposure, levels of protein, RNA, DNA, glycogen and total lipid were determined and related to effects on survival and reproduction. The maximum allowable toxicant concentration based on survival and reproduction was between 158 and 811 μg/L DEHP. However, survival and reproduction were not the most sensitive parameters measured. A no observed effect concentration of 72 μg/L was identified by DNA content per individual on day 7, by RNA/DNA ratio on day 7 and by surfacing behavior ofDaphniaon day 0. Reduced protein growth was associated with increased RNA/DNA and protein/RNA/DNA ratios. Glycogen was the only biomolecule affected inDaphniaexposed to 811 μg/L DEHP f

ISSN:0730-7268    

DOI:10.1002/etc.5620060305

出版商:Wiley Periodicals, Inc.    

年代:1987

数据来源: WILEY

摘要:

AbstractUrine samples from 80 forest workers applying 2,4‐D [(2,4‐dichlorophenoxy)acetic acid] plus dichlorprop [(±)‐2‐(2,4‐dichlorophenoxy)propanoic acid]or picloram (4‐amino‐3,5,6‐trichloro‐2‐pyridinecarboxylic acid) by ground techniques were monitored to determine the dose of chemical absorbed. Four crews of 20 workers each were studied to compare the exposures during application by backpack, injection bar, Hypohatchet or a hack‐and‐squirt method. Total urine output was analyzed to compare the absorbed dose to each worker under two operational modes. In the first, designated T‐1, the workers wore their usual clothing and followed the work habits they ordinarily used on the job. In the second mode, designated T‐2 and conducted 6 d after the first, workers were given new leather gloves and boots and asked to take all feasible precautions to prevent herbicide exposure and to wash immediately if they come into contact with the chemical.For all application methods except that with backpacks, the T‐2 treatment decreased the absorbed dose. During both T‐1 and T‐2 the clothing of backpack sprayers often became saturated with spray, dew or perspiration, and these workers received a higher absorbed dose of 2,4‐D (0.04–0.24 mg/kg body weight) than did workers in other crews. The absorbed dose of dichlorprop ranged from undetectable to 0.18 mg/kg. Hypohatchet workers received a greater dose than did injection bar or hack‐and‐squirt workers. The absorbed dose of picloram ranged from undetectable to 0.02 mg/kg. If equal dermal penetration of 2,4‐D and picloram is assumed, this represents much less dermal absorption than would have been predicted from the relative amo

ISSN:0730-7268    

DOI:10.1002/etc.5620060306

出版商:Wiley Periodicals, Inc.    

年代:1987

数据来源: WILEY

摘要:

AbstractA computer‐automated behavioral assay was used to assess the effects of reduced ambient pH on the response of fathead minnows to chemical feeding stimuli. The testing system quantified eight behavioral parameters based on the activity level of individual fish before and after exposure to a single‐pulse dose of a feeding stimulus—a tissue culture medium (1 ml; Eagle minimum essential medium with Earl's salts and L‐glutamine) — injected into the water circulation. Twentyfive adult minnows were tested after exposure to one of five pH levels: 8.0 (control), 7.0, 6.5, 6.0 and 5.5. Complete elimination of the feeding response occurred at pH = 6 and lower; responses at higher pH levels were not statistically different from those in the controls. Differences in water hardness (160 mg/L CaCO3) and duration of exposure (72 h versus 30 d) had no influence on the pattern or degree of the pH effects. Scanning electron microscopy revealed no pathological or gross morphological correlates of the behavioral changes. To test for possible recovery, minnows that did not respond at pH = 6 were placed in water of control pH (8.0) for 24 h and then tested again; a statistically significant response to the feeding stimulus was restored. These results indicate that acute and chronic sublethal levels of acidification caused a reversible impairment of chemoreception and that the impairment can occur at a relatively high pH. The toxic effect probably involves mechanical and chemical inhibition of receptor cells in the olfactory and gustatory epithelia rather than actual destruction of chemosensory tissue. In nature, reduction of pH to approximately 6.0 could impair feeding behavior and reduce food intake, fecundity and long‐term survival of fathead minnow populations. Our results correspond well with environmental studies that show that fathead minnows are eliminated from natural waters when pH levels reach

ISSN:0730-7268    

DOI:10.1002/etc.5620060307

出版商:Wiley Periodicals, Inc.    

年代:1987

数据来源: WILEY