摘要:

AbstractA toxicity assay based on inhibition of β‐galactosidase biosynthesis was compared to a similar assay based on inhibition of β‐galactosidase activity. In both tests,Escherichia coligrown in a minimal medium was exposed to isopropyl‐β‐thiogalactoside to induce β‐galactosidase biosynthesis. The induction step preceded contact of cells with the toxicant in the enzyme activity assay, whereas in the enzyme biosynthesis test, the inducer was added following contact of cells with the toxicant. Relative sensitivity was judged on the basis of responses to the heavy metals Hg2+, Cu2+, and Cd2+, and the organics 3,4‐dichlorophenol, formaldehyde, Hydrothol, phenol, sodium dodecyl sulphate, and toluene. Comparison of these results to the IC50s achieved with other microbial systems,Daphniabioassay, and fish bioassay indicates that the enzyme activity test was moderately sensitive to heavy metals but was insensitive to organic toxicants. The test based on inhibition of enzyme biosynthesis was sensitive to both heavy metals and

ISSN:0884-8181    

DOI:10.1002/tox.2540030302

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractA surrogate test battery was evaluated at several stream and landfill sites where toxicant contamination had occurred. The battery consisted of microbial activity assays and macrofaunal organisms: alkaline phosphatase, amylase, arylsulfatase, electron transport system activity, β‐galactosidase, β‐glucosidase, protease, metal resistance, heterotrophic uptake (14C), zooplankton (Daphnia magna, Ceriodaphnia), amphipods (Hyalella azteca), and fathead minnows (Pimephales promelas). Waters, leachates, and sediments were tested for toxicity from sites in 5 states. Surrogate responses were correlated within situbiological and/or chemical parameters. At each test site, statistically significant relationships were observed between microbial test responses andin situbiological or chemical responses, revealing both toxicant impacts and natural variations. Field validation of this test approach revealed its sensitivity and versatility, supporting its use in routine toxicant impact assess

ISSN:0884-8181    

DOI:10.1002/tox.2540030303

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractThe N‐cycle of an Aldicarb‐contaminated [2.5 g · m−2(a.i.)] soil cover of a newly graded rubble dump was investigated in order to judge the alterations of microbial nitrogen transformations at the ecosystem level. The pesticide reduced the kinetic parameters of nitrification (maximum activity and division rate) markedly, indicating severe damage to the nitrifying population of the soil during the first 16 weeks after its application. The degree of nitrification varied depending on the incubation conditions. Incubations in the field and under laboratory conditions without substrate addition showed negligible effects, whereas incubation with the addition of (NH4)2SO4led to an intolerable reduction in nitrification.The consequences of these experimental results on the NO3‐N and NH4+‐N content of the soil solution were analyzed by simulating the N‐cycle using different sets of parameters (climatic factors, initial conditions). The results indicate that combining field and laboratory studies of microbial populations with a computer simulation model of the N‐cycle improves ecotoxicological r

ISSN:0884-8181    

DOI:10.1002/tox.2540030304

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractThe RK mutatest is a recently developed, forward, short‐term, bacterial genetic test system for quantitation of mutagenic activity and toxicity. Rapid quantitative, semi‐quantitative, and qualitative variations of the standard RK mutatest protocol were developed and tested using reference genotoxic agents. Several of the reported mutatest modifications considerably reduced assay time, and would be useful for a quick first‐stage evaluation of the biological damaging effect of environmental subst

ISSN:0884-8181    

DOI:10.1002/tox.2540030305

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractThis paper reports the application of a battery of microbiological and toxicant screening tests to sediments collected from the Port Hope area. The sediments were extracted using Milli‐Q water and solvents. The solvent extracts indicated that the whole sampling area has been impacted by toxic chemicals. TheDaphnia magnatest was the most sensitive screening test in Milli‐Q water extracts. Microbiological studies indicated that the sampling area was, and is continuing to be, impacted by fecal pollut

ISSN:0884-8181    

DOI:10.1002/tox.2540030306

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractOrganic extracts isolated from coastal sediments off Barcelona were submitted to theSalmonella/microsomal mammalian mutagenicity test (strains TA 98, 100, and 1538). The results obtained were ambiguous and a lack of dose‐response correlation was observed. However, when the extracts were resolved in fractions of increasing polarity these showed a parallel increase in mutagenicity, although the most polar were toxic. This seems to indicate that interferences among components may occur and a chemical class fractionation is needed for a better assessment of the mutagenicity of these samples.Polycyclic aromatic hydrocarbons (benzofluoranthenes, benzo[a]pyrene, and alkyl‐substituted benzo[a]anthracenes) identified in the intermediate fractions by HRGC‐MS, could account for the mutagenicity observed. However, in the polar fractions only biogenic components (e.g., linear and steroidal alcohols and ketones) and traces of toxic xenobiotics (e.g., nonylphenol derivatives) were identified. On these grounds, it is suggested that the mutagenicity of some unknown components could be enhanced by the concurrence of the cocarcinogenic lipids

ISSN:0884-8181    

DOI:10.1002/tox.2540030307

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractToxic effects of Cd++, Cu++, and Zn++onSelenastrum capricornutumwere evaluated in various experimental conditions in order to determine the influence of the composition of the test medium and of the concentration of the algal biomass on the toxicity of metals to algae. Four media recommended in different standard methods (International Standards Organisation, U.S. Environmental Protection Agency, Organisation for Economic Cooperation and Development, AFNOR) were compared. Results of algal bioassays showed that the sensitivity of algae during the exponential growth phase was not influenced by the concentration of macronutrients in the medium.On the contrary, the numeration of the algal suspensions tested appeared determinant as the toxicity decreased when the quantity of algal inoculum was increased: with inocula of nearly 3 × 104, 2.5 × 105, 6 × 105, and 3 × 106cells/mL att= 0, the corresponding EC50were 46, 80, 110, and up to 300 μg/L for cadmium, 10, 65, 105, and 280 μg/L for copper, and 90, 163, 225, and 365 μg/L for zinc. Modifications in the speciation forms of the metal induced by a rapid increase of the pH could be responsible for part of this decreased to

ISSN:0884-8181    

DOI:10.1002/tox.2540030308

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

ISSN:0884-8181    

DOI:10.1002/tox.2540030309

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

ISSN:0884-8181    

DOI:10.1002/tox.2540030310

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

ISSN:0884-8181    

DOI:10.1002/tox.2540030301

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY