摘要:

AbstractThe effect of tributyltin (TBT) was examined on six enzymes in intact cells and in cytosol and wall/membrane fractions of four bacteria. The organisms′ TBT resistance varied over 2,400‐fold:Pseudomonas putidaTBT‐6>Pseudomonassp. BP‐4>Bacillussp. Me‐I>Bacillussp. MC‐24S. TBT is not a general toxicant for enzymes since β‐galactosidase, glucose dehydrogenase, and alkaline phosphatase were not affected by it. ATPase was detected in cells of all four organisms but not in their cell fractions; it was inhibited by TBT in cells ofBacillussp. MC‐24S. In intact cells and the membrane fraction, TBT stimulated NADH oxidase at low levels and inhibited it at higher levels, and the more resistant organisms had a higher threshold concentration. InPseudomonassp. BP‐4, TBT had no effect on glucose‐6‐phosphate dehydrogenase in cells, but inhibited it in the cytosol fraction. TBT did not affect the periplasmic alkaline phosphatase, which was present in the twoPseudomonasspp. The results support the conclusion that the cell membrane is a site of action of TBT, but that it can also act in the cytoplasm, for the cytosolic enzyme glucose‐6‐phosphate dehydrogenase was stimulated in cells ofBacillussp. MC‐24S. Enzymes requiring free sulfhydryl groups were inhibited. The patterns of enzyme sensitivity to TBT suggest there may be two resistance mechanism

ISSN:0730-7268    

DOI:10.1002/etc.5620140701

出版商:Wiley Periodicals, Inc.    

年代:1995

数据来源: WILEY

摘要:

AbstractThe occurrence of butyltin and phenyltin compounds in water, mussels, and sediment of freshwater boat harbors of Lake Lucerne, Switzerland, and six Swiss river systems was determined between 1991 and 1993 following the sales ban of organotin‐containing antifouling paints. In harbor waters, average levels of tributyltin (TBT) were between 40 and 50 ng/L in 1993, which was one order of magnitude lower than in 1988. Residues of up to 9.2 μg/g TBT and 0.7 μg/g triphenyltin (TPT) occurred in zebra mussels (Dreissena polymorpha) and were related to the water concentrations. In a sediment core, high levels of TBT and TPT occurred in the upper 7 cm and 5.5 cm, respectively, with significant decreases below. Estimated sedimentation rates and the fact that transformation products did not increase with depth indicate that TBT and TPT are persistent in these sediments. In all rivers, di‐ and/or monobutyltin of up to 46 ng/L occurred consistently, and occasionally TBT and TPT of up to 26 and 11 ng/L, respectively. This study indicates that even though regulations were effective in reducing TBT and TPT levels in boat harbor water, contamination of surface fresh waters including rivers by organotin compounds is still widespread and has ecotoxicological consequences. Moreover, harbor sediments represent long‐term reservoirs of these co

ISSN:0730-7268    

DOI:10.1002/etc.5620140702

出版商:Wiley Periodicals, Inc.    

年代:1995

数据来源: WILEY

摘要:

AbstractThe purpose of this work was to investigate the effect of sorbate structure, by using the quantitative structure‐activity relationship (QSAR) approach, on sorption of organic compounds by two soils with different amounts of organic matter. Miscible displacement experiments were performed with several organic contaminants representing six classes of nonpolar, nonionizable organic chemicals, including chlorinated aliphatics, chlorobenzenes, polycyclic aromatic hydrocarbons (PAHs),n‐alkylbenzenes, methylated benzenes, and polychlorinated biphenyls (PCBs). The breakthrough curves were analyzed by using a bicontinuum model wherein sorption is assumed to be instantaneous for a fraction of the sorbent and rate limited for the remainder. The QSAR approach was used to investigate the dependency of both equilibrium and nonequilibrium sorption coefficients on topological descriptors representing structural properties of the solutes. For both equilibrium and nonequilibrium parameters, the first‐order valence molecular connectivity (1Xv) was found to be the best topological descriptor. Most of the rate‐limited sorption behavior could be explained by accounting for the size and structure of the solute molecule, as indicated by the good correlation between the rate coefficient and1Xv. This supports the contention that rate‐limited sorption in these systems is controlled by a physical diffusion mechanism, consistent with the polymer diffusion model. Based on this model, the calculated diffusion‐length ratios for the Borden and Mt. Lemmon soils, which have a large difference in organic‐matter contents, compare favorably to the values determined from the measu

ISSN:0730-7268    

DOI:10.1002/etc.5620140703

出版商:Wiley Periodicals, Inc.    

年代:1995

数据来源: WILEY

摘要:

AbstractThe transport and biological effects of dormant spray pesticides were examined in the San Francisco Estuary, California, by measuring dissolved‐pesticide concentrations and estimating toxicity using bioassays at a series of sites in January and February 1993. Distinct pulses of pesticides, including diazinon, methidathion, and chlorpyrifos, were detected in the San Joaquin River in January and February and in the Sacramento River in February following rainfall. The higher pesticide loads in the Sacramento River compared with those in the San Joaquin River can be attributed to the greater amount of rainfall in the Sacramento Valley. The use patterns and water solubility of the pesticides can account for the observed temporal and spatial distributions in the two rivers. The pesticide pulses detected at Sacramento were followed through the northern embayment of San Francisco Estuary. In contrast, the pesticide distribution in the Sacramento‐San Joaquin Delta changed from distinct pulses to steady increases in concentration over time. Seven‐day bioassays indicated that Sacramento River water at Rio Vista was acutely toxic toCeriodaphnia dubia(water flea) for 3 consecutive d and San Joaquin River water at Vernalis for 12 consecutive d. These water samples all had the highest diazinon concentrations. Examination of 96‐h LC50 values (lethal concentration that kills 50% of test organisms in 96 H) indicates that measured diazinon concentrations could account for most but not all the observed toxicity. Other pesticides present could contribute to the t

ISSN:0730-7268    

DOI:10.1002/etc.5620140704

出版商:Wiley Periodicals, Inc.    

年代:1995

数据来源: WILEY

摘要:

AbstractA study was conducted to determine the availability of hydrophobic compounds within surfactant micelles for microbial uptake. Several of the surfactants tested were toxic to the test bacteria and prevented biodegradation of biphenyl and phenanthrene at concentrations below the critical micelle concentration (CMC). The rate of biodegradation was reduced at a surfactant concentration above but not below the CMC only when the test bacterium grew on biphenyl in the presence of Triton X‐100. This decrease was correlated with the CMC and was more pronounced at a biphenyl concentration of 0.2 μg/ml than at 2.0 μg/ml. Such a correlation was not observed when bacteria grew on 1.0 μg glutamate per ml, even though the rate of glutamate degradation was reduced by Triton X‐100. Analysis of the data with a mathematical model suggested that the experimental observations were probably not the consequence of the unavailability to bacteria of biphenyl within Triton X‐100

ISSN:0730-7268    

DOI:10.1002/etc.5620140705

出版商:Wiley Periodicals, Inc.    

年代:1995

数据来源: WILEY

摘要:

AbstractIn this study we describe the use of a transgenic cell line for the identification of potentially toxic compounds in test solutions and environmental samples. The reporter gene system (RGS), derived from a human liver cancer cell line, has been engineered such that the CYP1A1 gene, when activated by an inducer compound, will produce luciferase instead of P450. Eighteen hours after application of an inducer the reaction is stopped by rinsing, the cells lysed, and the cytoplasm measured for luminescence and protein content (for normalization). Induction by such compounds as dioxin, dioxin‐like PCB congeners (co‐planars), and polycyclic aromatic hydrocarbons (PAHs) infers these xenobiotics are present at levels that are potentially toxic, carcinogenic, or mutagenic to organisms. Multiple wells with attached cells in 2 ml of media were inoculated with various concentrations of toxicants in organic solvents (including DMSO, toluene, and dichloromethane). Volumes tested successfully thus far are 2 to 20 μl of solvent. Solvent extracts (using standard extraction methods) of aquatic sediments were directly applied to the assay system. Test results show significant RGS induction from concentrations of inducer compound that, if present in a typical 40‐g sediment sample, would be (in ng/g or ppb): 0.05 for dioxin; 10 to 1,000 for a range of coplanar PCB congeners; about 2,000 for several Aroclor mixtures; and 300 for a mixture of PAHs. A mixture of pesticides at concentrations about four times the PAH levels did not produce an induction response. Results presented here indicate that testing for the presence of potentially toxic chemicals in environmental samples could be performed rapidly, with sensitivity and specificity using this RGS cel

ISSN:0730-7268    

DOI:10.1002/etc.5620140706

出版商:Wiley Periodicals, Inc.    

年代:1995

数据来源: WILEY

摘要:

AbstractWeekly atmospheric deposition samples were collected from early May to early September during 1984 to 1987 in a small agricultural watershed near Regina, Saskatchewan, an area in the midst of extensive agricultural pesticide use in the Canadian prairies. “Bulk” deposition samples were collected weekly in duplicate and analyzed for six herbicides (bromoxynil, 2,4–D, dicamba, diclofop, triallate, and trifluralin) and five insecticides (carbaryl, carbofuran, chlorpyrifos, deltamethrin, and dimethoate). In general, no significant differences were found among the duplicate samples. Over the 4‐year period, the frequency of weekly detection of herbicides during the growing seasons was 0, 32, 39, 53, 58, and 67% for trifluralin, bromoxynil, triallate, diclofop, dicamba, and 2,4–D, respectively. For insecticides, only carbaryl and carbofuran were detected in one to two samples in the years for which the insecticides were analyzed. This infrequent detection reflected the relatively high detection limits set for the insecticides as compared to those for the herbicides. The seasonal herbicide atmospheric deposits during the growing period over the 4‐year period (mg ha−1) ranged from 90 to 234 (bromoxynil), 386 to 1,374 (2,4‐D), 20 to 219 (dicamba), 43 to 338 (diclofop), and 9 to 260 (triallate). Highest deposition rates were measured during and immediately following the spraying periods, with lesser, but significant, amounts also being detected during the harvest opera

ISSN:0730-7268    

DOI:10.1002/etc.5620140707

出版商:Wiley Periodicals, Inc.    

年代:1995

数据来源: WILEY

摘要:

AbstractRecovery of 1‐, 7‐, 14‐, or 21‐d‐oldHyalella aztecafrom sediment was evaluated. Recovery of 1‐ and 7‐d‐old amphipods was below an acceptability criterion of 80% survival for sediment tests. Another important aspect to consider when conducting sediment tests withH. aztecais defining mortality. A second study was conducted to evaluate the decomposition rate of dead amphipods in sediment. Regardless of sediment type, ≥ 90% of the amphipods started to break apart within 12 h of death; specifically, the head separates from the body. Therefore, if an immobile amphipod with its head and body intact is recovered in sieved material, it was probably alive within 12 h of the end of the test (an amphipod may be alive before sieving but may die during the sieving process). However, immobile amphipods removed from the sediment surface before sieving are

ISSN:0730-7268    

DOI:10.1002/etc.5620140708

出版商:Wiley Periodicals, Inc.    

年代:1995

数据来源: WILEY

摘要:

AbstractThe organophosphorus insecticide Malathion 60 is used to control terrestrial arthropod pests on watercress,Rorippa nasturtium‐aquaticumL. (Hayek). The use of this pesticide could damage aquatic invertebrate communities in nearby chalk streams, so an in situ experiment was undertaken with the amphipodGammarus pulexL. to determine the extent of this risk. CagedG. pulexwere placed below two selected watercress beds and their associated settling pools, and their mortality, feeding rate, and acetylcholinesterase activity measured before and after the application of Malathion 60 to the watercress crop. The differences found between prespray and postspray samples ofG. pulextaken from the stations immediately below both watercress beds follow: (a) the acetylcholinesterase activity was significantly lower at both stations after spray application; (b) the mortality rate was significantly higher at one station after spray application, but not at the other; (c) there were no clear effects on feeding rates at either station. Also, there were no significant detrimental effects at either of the stations located below the settling pools. Results from this study suggest that the use of Malathion 60 on watercress beds at recommended rates presents little risk toG. pulexliving in streams below watercress farms if bed effluent passes through a settling pool before releas

ISSN:0730-7268    

DOI:10.1002/etc.5620140709

出版商:Wiley Periodicals, Inc.    

年代:1995

数据来源: WILEY

摘要:

AbstractThe use of the 14‐d earthworm toxicity test to aid in the evaluation of the ecological impact of contaminated soils is becoming increasingly widespread. However, the method is in need of further standardization. As part of this continuing process, the choice of reference toxicants was evaluated. Reference toxicants were rated in relation to the following criteria: (a) reproducibility, (b) low human health hazard, (c) feasibility of measurement, and (d) chemical stability. Potassium chloride (KCl) and ammonium chloride (NH4Cl) were evaluated as possible alternatives to the one currently in common use, 2‐chloroacetamide. Potassium chloride rated the best for the combination of the four criteria, followed by NH4Cl and 2‐chloroacetamide. Coefficients of variation (C.V.s) from control charts of six definitive tests were used to measure reproducibility. The best reproducibility (lowest C.V.) was shown by KCl, followed by NH4Cl and 2‐chloroacetamide. Toxicants ranked KCl2‐chloroacetamide in terms of measurement feasibility. Both 2‐chloroacetamide and NH4Cl changed in concentration during testing. Evidence is also presented that 2‐chloroacetamide degrades rapidly during testing, and that, as dead worms decay, ammonification may be adding another toxicant,

ISSN:0730-7268    

DOI:10.1002/etc.5620140710

出版商:Wiley Periodicals, Inc.    

年代:1995

数据来源: WILEY