ISSN:0730-7268    

DOI:10.1002/etc.5620081001

出版商:Wiley Periodicals, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractSorption isotherms were measured by batch equilibration methods for three nonpolar organic sorbates on seven subsurface, low‐carbon sedimentary aquifer materials. Radiolabeled (14C) 1‐methylnaphthalene,o‐dichlorobenzene and naphthalene were separately equilibrated with the sorbents to determine sorption coefficients (K). Chemical and physical properties of the aquifer materials were determined.Possible relationships between sorption coefficients and organic carbon (OC) content and other sorbent properties were investigated using multivariate statistics. Sorbent properties used in the statistical analysis were sorption coefficients, percentage OC, percentage sand, percentage clay, percentage silt, specific surface area, cation exchange capacity, percentage 1:1 clay, percentage 2:1 clay and percentage iron content. No predictive relationships between sorption coefficients and aquifer material properties were found. The sorption coefficient does not correlate with any of the properties of the aquifer materials, including OC content for aquifer materials with OC content of less than 0.10%. It is recommended that sorption coefficients be determined experimentally on each different aquifer material for use in ground water transport calcula

ISSN:0730-7268    

DOI:10.1002/etc.5620081002

出版商:Wiley Periodicals, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractPhenol, 2‐chlorophenol, 2,4‐dimethylphenol, 2‐nitrophenol, 4‐nitrophenol, 2,4‐dinitrophenol, 3‐methyl‐4‐chlorophenol (4‐chloro‐m‐cresol) and 2‐methyl‐4,6‐dinitrophenol (4,6‐dinitro‐o‐cresol) were evaluated for their anaerobic biodegradability and toxicity to methanogenesis using two anaerobic bioassays, the biochemical methane potential (BMP) and the anaerobic toxicity assay (ATA). The BMP and ATA were used to evaluate the stoichiometric conversion of added substrate carbon to CO2and CH4. Each substrate was the only added carbon source (20‐200 mg/L) prepared in prereduced defined medium using a 10% (v/v) inoculum of municipal digester sludge. All concentrations of phenol and low concentrations (20 mg/L) of 2‐chlorophenol, 2‐nitrophenol, 4‐nitrophenol and 2,4‐dinitrophenol were completely mineralized. Higher concentrations of these same substrates (100 mg/L) and all concentrations of dimethylphenol, 3‐methyl‐4‐chlorophenol and 2‐methyl‐4,6‐dinitrophenol were observed to undergo no significant mineralization of added substrate and inhibited methanogenesis to varying degrees. Significant biotransformation of the monosubstituted nitrophenols occurred, resulting in the production of the corresponding aminophenols. Acclimation for most compounds took several days to weeks before methane could be detected in the substrate‐amended cultures. Generally, the greater the substitution of the phenolic ring, the greater were the recalcitrance and toxicity of the substrate. The fate of these compounds can be significantly influenced by both their conc

ISSN:0730-7268    

DOI:10.1002/etc.5620081003

出版商:Wiley Periodicals, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractGulf toadfish,Opsanus beta, were exposed to initial [14C]benzo[a]pyrene (BaP) concentrations of 5μg/L in a simple static system at high and low temperatures (18 or 28°C) following long‐term (>4 weeks) acclimation to these temperatures or an acute temperature change (18 to 28°C or 28 to 18°C) to assess the effects of temperature on the uptake and disposition of BaP. BaP uptake was estimated from the disappearance of BaP from the water. Uptake rates estimated at initial BaP concentrations for the four temperature treatments (acclimation temperature: exposure temperature), 28:18, 28:28, 18:18 and 18:28°C, were 0.020 ± 0.001, 0.051 ± 0.005, 0.031 ± 0.004 and 0.065 ± 0.004 μg BaP/g body weight/h (±se,N= 6). The decrease in BaP uptake with decreasing BaP concentration indicates that BaP uptake is directly proportional to the concentration in water, and calculatedQ10values suggest that uptake is modulated by temperature‐induced changes in respiration rate or convection volume. BaP was detected in all tissues examined, with the highest levels in the bile, the liver, the kidney and the gills. Greater uptake rates of carcinogens such as BaP at higher temperatures may in part explain higher rates of tumor formation in fish exposed to carcinogens at hig

ISSN:0730-7268    

DOI:10.1002/etc.5620081004

出版商:Wiley Periodicals, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractRainbow trout (Salmo gairdneri) were exposed orally ton‐butylcyclohexane and on the sixth day after ingestion, 3 to 5% of the dose of parent compound was recovered as a metabolite in the bile. The glucuronide ofcis‐3‐n‐butylcyclohexanol was identified as the single metabolic product. Exposure of trout tot‐butylcyclohexane afforded the glucuronide of 4‐t‐butylcyclohexanol in a much smaller amount. Comparative studies between these two small naphthenic hydrocarbons and the corresponding aromatic molecules are

ISSN:0730-7268    

DOI:10.1002/etc.5620081005

出版商:Wiley Periodicals, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractThe amelioration of cadmium toxicity by zinc was measured in terms of changes in the maximum specific growth rate (μmax) of aChlorella pyrenoidosapopulation using turbidostat culture. In this continuous culture system, μmaxis a dependent variable that responds directly to toxic effects. At a sublethal cadmium concentration (2.05 μM Cd) in the medium, the population μmaxwas in steady state at 70% of control values. When zinc was added to the medium to a concentration of 4.08 μM Zn, μmaxincreased immediately to a rate of 2.2% of control μmax/generation for seven generations, reaching steady state at 90% of the control. Additional increases in zinc did not elicit further increases in μmax. Full recovery of μmaxsubsequently occurred after five generations in control medium. Mean cell size and percentage dry mass also changed during periods of toxicity and amelioration. Mechanisms of the amelioration process are d

ISSN:0730-7268    

DOI:10.1002/etc.5620081006

出版商:Wiley Periodicals, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractTwo freshwater sediments containing 3 and 11% total organic carbon (TOC) were spiked with DDT and endrin to compare the effects of cold (4°C) and frozen (−20°C) storage of the sediment on toxicity to the amphipodHyalella aztecain 10‐d tests. Toxicity of the DDT‐spiked sediment was reduced when it was frozen for 14 d. LC50 values for cold‐stored and frozen‐stored sediments were 4.2 and 7.3 μg/g DDT (calculated on dry solids basis) at 3% sediment TOC and 11.1 and 23.2 μg/g DDT at 11% sediment TOC, respectively. Toxicity of the 3% TOC endrin‐spiked sediment was reduced by freezing; it exhibited LC50s of 5.1 and 7.7 μg/g endrin, respectively, for cold and frozen storage. Toxicity of endrin in two tests in the 11% TOC sediment remained essentially unchanged by freezing. LC50s were 19.6 and 21.7 μg/g endrin for cold and frozen sediments in one test and 10.3 and 9.8 μg/g endrin in the second test. Decreased toxicity was assumed to be related to the release of soluble organic carbon from the sediments during freezing and thawing. Relative differences in toxicity between DDT and endrin for cold and frozen sediments appear to be related to the different adsorptions of the chemicals onto t

ISSN:0730-7268    

DOI:10.1002/etc.5620081007

出版商:Wiley Periodicals, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractEffluent toxicity testing is a routine National Pollutant Discharge Elimination System (NPDES) permit monitoring requirement for many municipal and industrial dischargers. Effluent toxicity compliance limits are being set in an increasing effort to limit discharge of toxics into U.S. water bodies. To that end, hazard assessment principles are being applied to limit discharged toxicity based on instream effects as judged by effluent toxicity, fate and exposure. Uncertainty arises in complying with effluent toxicity limits because of a number of factors, including an unacceptably toxic effluent, error in conducting a specified test, test organism health, statistical variability and interferences in the test solution that mask the toxic effect.Three factors that may influence compliance with toxicity limits and/or identification of toxics are discussed. These factors indicate the need for additional consideration before setting permit limits, determining requirements for toxicity reduction and possibly implementing additional effluent treatment.Comparisons between reference toxicant data and control mortality showed that reference toxicant data provide an additional control for determining whether effluent toxicity test results are valid and that they can be used to test regulatory compliance. Statistical sampling theory was explored to determine compliance with an effluent toxicity requirement of 80% survival in 100% effluent. Third, several test species were used to determine the causative toxic agents in order to correctly identify toxicity and to separate true toxic effects from interferences in exposures to receiving water.

ISSN:0730-7268    

DOI:10.1002/etc.5620081008

出版商:Wiley Periodicals, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractEastern screech‐owls (Otus asio) were fed diets containing 10 ppm Kelthane® with 3.4% DDT‐related contaminants (old technical formulation), 10 ppm Kelthane with no detectable DDT contaminants (new technical formulation) or a control diet. Food consumption, adult weight and date of initiation of egg laying were similar for birds in control and dosed treatment groups. Most measures of reproductive success were similar for control and dosed treatment groups. Shell weight and thickness index were significantly lower for both dosed groups than for controls. Shell thickness was significantly lower for the new Kelthane treatment than for controls. Concentrations ofp,p'‐DDE were significantly higher in eggs laid by pairs receiving old Kelthane than in those of birds receiving new Kelthane or in controls. Concentrations of dichlorobenzophenone, dicofol and dechlorodicofols were significantly higher in carcasses of dosed owls than in controls, whereas concentrations of DDE were significantly higher in carcasses of owls fed old Kelthane than in controls or owls fed new Ke

ISSN:0730-7268    

DOI:10.1002/etc.5620081009

出版商:Wiley Periodicals, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractFreshwater algal blooms associated with outbreaks of sudden death in ducks and swine were examined for cholinesterase (ChE)‐inhibiting toxins as the possible cause of death. In both investigations,Anabaena flos‐aquaewas identified as the predominant alga in the bloom material. In both cases, assays on tissues from mice dosed intraperitoneally with algal extracts revealed inhibition of ChE in whole blood, plasma, diaphragm and lung, but not in brain. With algae from the field case involving ducks, toxicosis was experimentally reproduced by oral intubation in ducks and swine, but not in mice and a steer. However, the steer, as with other species, was susceptible to toxicosis induced by parenteral administration of an algal extract. Assays on tissues from affected animals revealed inhibition of ChE in whole blood, plasma, red blood cells, diaphragm, lung and pectoral muscle, but not in brain or retina. In vitro electric eel (EC 3.1.1.7) ChE assays with HPLC‐purified extracts of the same alga revealed direct inhibition of acetylcholinesterase. Clinical signs in all animals were compatible with muscarinic and nicotinic cholinergic stimulation. Death of exposed animals is an apparent result of peripheral ChE inhib

ISSN:0730-7268    

DOI:10.1002/etc.5620081010

出版商:Wiley Periodicals, Inc.    

年代:1989

数据来源: WILEY