ISSN:0730-7268    

DOI:10.1002/etc.5620080701

出版商:Wiley Periodicals, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractThe hydrolysis kinetics of 4‐chlorostilbene oxide (CSO) in buffered distilled water, in natural waters and in sediment‐associated water are reported. The disappearance of CSO followed pseudo‐first‐order kinetics in buffered distilled water over the experimental pH range of 3 to 11. Below pH 5, acid‐catalyzed hydrolysis dominates, with a second‐order rate constant of 11.3 (±1.0) M−1min−1. Above pH 5, hydrolysis is independent of pH, with a rate constant of 1.02 (±0.12) × 10−4min−1at 25°C. In natural waters, the hydrolysis rate constant of CSO had an average value of 0.59 (±0.12) × 10−4min−1. In sediment‐associated water, the observed rate constant was 1.70 (±0.05) × 10−4min−1. Sorption of CSO to the humic materials in natural waters and biotic effects in sediment‐associated water appropriately explain the differences from sterile buffer solutions. Buffer catalysis was observed, but on the other hand, a negative ionic strength effect was determined. The formation of diastereoisomers of 1‐(4‐chlorophenyl)‐2‐phenylethylene glycol as major products at both acidic and neutral pH values suggests that CSO undergoes acid‐catalyzed as well as neutral hydrolysis reactions through an A‐1 carbonium ion mechanism. The rate constant for hydrolysis of CSO at pH 14 is only 70% faster than the hydrolysis rate constant over the pH range of 5 to 11, which suggests that nucleophilic addition of hydroxide ion is not the main hydro

ISSN:0730-7268    

DOI:10.1002/etc.5620080702

出版商:Wiley Periodicals, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractBecause of the highly controlled environment in which they live and their unique genetic history, the gut microflora of some insects may be useful for studying some of the underlying principles that govern the kinetics of uptake and metabolism of substrates by microorganisms. In the present studies, D‐glucose mineralization kinetics were investigated using facultative anaerobes from termite gut microflora to test the similarity of kinetics principles developed previously with aquatic environmental microbial samples. As with environmental samples, heterogeneous kinetics were observed in the gut microflora, with increasingly enhanced glucose removal rates at diminishing amended substrate concentrations. These results lend support to the general applicability of these kinetics principles to a diversity of mixed microbial populations having greatly dissimilar environmental historie

ISSN:0730-7268    

DOI:10.1002/etc.5620080703

出版商:Wiley Periodicals, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractPhthalate, dimethyl phthalate, diethyl phthalate, dibutyl phthalate and di(2‐ethylhexyl) phthalate were evaluated for their anaerobic biodegradability and toxicity to methanogenesis. Two anaerobic bioassays (the biochemical methane potential and the anaerobic toxicity assay) were used to monitor the stoichiometric conversion of added substrate to carbon dioxide and methane. Each phthalic acid ester was the only added carbon source (20 to 200 mg/L) prepared in prereduced defined medium using a 10% (v/v) inoculum of municipal digester sludge. Over an extended incubation period (50 to 100 d), all concentrations of phthalate and dibutyl phthalate and low concentrations (20 mg/L) of dimethyl phthalate and diethyl phthalate achieved 75 to 100% of their theoretical methane potentials. Higher concentrations (100 to 200 mg/L) of dimethyl phthalate and diethyl phthalate achieved 25 to 50% of their theoretical methane potentials. Di(2‐ethylhexyl) phthalate showed little mineralization at any concentration, although biotransformation of this substrate was indicated. Acclimation for most of the compounds took several days to weeks before degradation commenced. In the anaerobic toxicity assay, only concentrations greater than 20 mg/L diethyl phthalate produced any significant suppression of methanogenesis over time. All other substrates produced little inhibition of methanogenesis during the initial period of incubation. Generally, increased incubation led to increased levels of methane production above active control levels. Thus, many of these compounds were metabolized completely under methanogenic conditions and were observed to produce little inhibition of methane production. Their fate, therefore, may be significantly influenced by their concentration and residence time in methanogenic habit

ISSN:0730-7268    

DOI:10.1002/etc.5620080704

出版商:Wiley Periodicals, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractIn connection with requirements of California's Toxic Air Contaminant Act, 24‐h ambient air samples were collected using an XAD‐4 resin trap technique capable of simultaneously collecting methyl parathion, methyl paraoxon, molinate and thiobencarb. Sampling was conducted on rooftops of public buildings located in four towns in two counties where methyl parathion, molinate and thiobencarb were used in significant quantities, and at a background site located in a county where no use occurred, for four intervals each week for 5 weeks during the springtime application period of 1986. Satisfactory recoveries (greater than 66%) were obtained from dynamic spiking experiments, and the precision from field replicates was consistently less than 50% relative standard deviation using a protocol designed to accommodate a large number of samples. Daily maximum average concentrations (and the range in averages for all sites over the 19 and 20 sampling days in the two‐county use area) were 25.7 ng/m3(0.2‐6.2 ng/m3) for methyl parathion, 3.1 ng/m3(<0.5‐0.8 ng/m3) for methyl paraoxon, 1,720 ng/m3(60‐650 ng/m3) for molinate and 250 ng/m3(12.9‐67.8 ng/m3) for thiobencarb. Concentrations correlated well with reported uses of methyl parathion and molinate in the general vicinity of the sampling sites. The likely sources of observed residue levels, based upon the method of application and pesticide physicochemical properties, were spray drift during application for methyl parathion, vapor‐phase oxidation of parent thion for methyl paraoxon, and postapplication volatilization from field water for molinate

ISSN:0730-7268    

DOI:10.1002/etc.5620080705

出版商:Wiley Periodicals, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractCurrent approaches to developing sediment quality criteria are reviewed and separated into two major groups: those approaches that provide only chemical‐by‐chemical criteria and those that provide criteria for chemical mixtures also. The individual approaches include background sediment chemistry, water quality criteria, sediment/water equilibrium partitioning, sediment bioas‐say, screening level concentration, apparent effects threshold and sediment quality triad. Based on the evaluation of the two groups and seven individual approaches, it is concluded that, for chemical‐by‐chemical criteria, the equilibrium partitioning method shows promise; for criteria that are also applicable to chemical mixtures, the apparent effects threshold/sediment quality triad approaches appear to be most appropriate. Recommendations are made concerning specific immediate research needs, related to developing effective, usable sediment quality

ISSN:0730-7268    

DOI:10.1002/etc.5620080706

出版商:Wiley Periodicals, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractThe cladoceranDaphnia magna, the amphipodsHyalella aztecaandGammarus lacustris, the annelid wormLumbriculus variegatusand the fathead minnowPimephales promelaswere exposed to hexachlorobenzene (HCB) in flow‐through tests ranging from 2 to 68 d in duration to determine the effects of HCB on survival, tissue bioconcentration andHyalellaandLumbriculusgrowth and reproduction.No effects on survival, growth or reproduction were observed at concentrations of HCB up to saturation (5.0 μ/L) or at tissue HCB concentrations of up to 223 μg/g. Tissue HCB concentrations increased with increasing water concentrations, and tissue bioconcentration values were generally similar. Rapid uptake and change of tissue HCB concentration with change in water concentration occurred, with rapid depuration when the animals were no longer exposed to HCB in the water column, and tissue HCB concentrations were correlated closely with HCB water concentrati

ISSN:0730-7268    

DOI:10.1002/etc.5620080707

出版商:Wiley Periodicals, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractGenetic plasticity in a mosquitofish (Gambusia affinisBaird and Girard) population was examined relative to acute mercury toxicity. Genotypes at eight loci (isocitrate dehydrogenase‐1 and ‐2, mannosephosphate isomerase, glucosephosphate isomerase‐2, fumarate hydratase, malate dehydrogenase‐1, leucylglycylglycine peptidase and phenylalanylproline peptidase) were scored using starch gel electrophoresis. Two null hypotheses were tested: (a) time to death does not differ between genotypes at individual loci and (b) time to death does not differ with multiple‐locus heterozygosity. Genotypes at three of the eight loci displayed significant effects on mosquitofish time to death. Multiple‐locus heterozygosity also had a significant effect on time to death. Significant amounts of genetic plasticity were found in a population of mosquitofish with no previous exposure to inorga

ISSN:0730-7268    

DOI:10.1002/etc.5620080708

出版商:Wiley Periodicals, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractThe toxicity of technical‐grade dinoseb, technical monosodium methanearsonate (MSMA), several formulations of each and a mixture of the two were tested using channel catfish (Ictalurus punctatusRafinesque) and fathead minnows (Pimephales promelasRafinesque) under standard conditions at 12°C in soft, reconstituted water. The 96‐h LC50s for technical dinoseb were 0.058 mg/L for channel catfish and 0.088 mg/L for fathead minnows. Differences among Vertac General®, Vertac Selective®, Premerge 3®, Gebutox® and technical dinoseb did not affect dinoseb toxicity to either fish species. The 96‐h LC50s for technical MSMA were 2,390 mg/L for channel catfish and 1,210 mg/L for fathead minnows. Formulation had a measurable effect on MSMA toxicity, with the Daconate® and Daconate 6® formulations nearly an order of magnitude more toxic than technical MSMA and Bueno 6® to both fish species. The mixture or joint toxicity of technical dinoseb and technical MSMA was greater than additive (synergistic), with additive toxicity indices for channel catfish and fathead minnows of 0.51 and 5.78,

ISSN:0730-7268    

DOI:10.1002/etc.5620080709

出版商:Wiley Periodicals, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractThe urchin,Lytechinus pictus, one of the most abundant species on the mainland shelf off southern California, was exposed to three of the most contaminated sediment types in the region and a control (reference) sediment. Mortality, growth, gonad production and bioaccumulation were measured in the laboratory for 60 d in flow‐through experiments. Significant mortality (49%) occurred in Santa Monica Bay sludge outfall sediment. Growth rates were significantly reduced in sediments from Los Angeles Harbor, Palos Verdes sewage outfall and Santa Monica Bay sludge outfall. Both male and female gonad production was significantly decreased in the Santa Monica Bay sludge and Palos Verdes outfall sediments. Gonads accumulated up to 12.6 ppm DDTs and 7.4 ppm polychlorinated biphenyls but decreased in concentrations of Zn, Cu and Cd. The biological effects measured could have been caused by several types of contaminants and were significantly correlated with many of the contaminants measured in the sediment

ISSN:0730-7268    

DOI:10.1002/etc.5620080710

出版商:Wiley Periodicals, Inc.    

年代:1989

数据来源: WILEY