摘要:

AbstractA direct INT‐dehydrogenase assay (DIDHA) was developed to measure chemical toxicity as well as toxicant interactions. This test consists of measuring quickly and directly the dehydrogenase activity (i.e., INT reduction) with the aid of a double beam spectrophotometer, thus avoiding formazan extraction and centrifugation steps. The assay was used to determine the toxicity of heavy metals, phenol, α‐naphtol, and herbicides (Barban, propanil, swep, BIPC, and CIPC). It was also useful in demonstrating the protective effect of clays and humic acids with regard to herbicide toxicity as well as antagonistic and synergistic interactions among toxic

ISSN:0884-8181    

DOI:10.1002/tox.2540010102

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

年代:1986

数据来源: WILEY

摘要:

AbstractOxygen uptake ofPseudomonas putidawas employed for the rapid screening of toxicants in water. Oxygen uptake was measured over a 10 minute period at constant temperature by means of a biological oxygen monitoring system connected to a potentiometric recorder. Sublethal concentrations of selected chemicals inhibited or stimulated oxygen uptake. AP. putidagrowth inhibition test proved more sensitive to most individual chemicals than the oxygen uptake assay, but yields results only after some 7 hours. Industrial effluent in low concentrations and domestic wastewater, stimulated both oxygen uptake and growth ofP. putida.Higher concentrations of industrial effluent and a laboratory mixture of selected toxicants inhibited both growth and oxygen uptake at equal levels of sensitivity. Sensitivity compared favourably with that of other rapid bioassays, and various toxicants were detected at concentrations well below those allowed in industrial effluents. Since theP. putidaoxygen uptake assay is relatively sensitive, simple, economical and exceptionally fast, it should prove useful for the rapid testing of many wastewaters and even excessive contamination of drinking‐water supplies while it may serve a valuable purpose as part of a battery of bioassays containing slower test

ISSN:0884-8181    

DOI:10.1002/tox.2540010103

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

年代:1986

数据来源: WILEY

摘要:

AbstractAssessment of the toxicity of chemicals to the respiration of activated sludge microorganisms is a relatively simple and reproducible method when applied to a standard population of bacteria. However, activated sludge is, by nature, a variable commodity, and varying results are often reported. Within‐plant variations can occur from day to day as a result of shifts in the bacterial population, probably caused by changes in the strength of components of the sewage feed. Between‐plant variations can be considerably greater. Factors such as differing operating conditions and presence of industrial waste waters in the sewage can result in differing species composition of the sludge, which, in turn, may account for differing biooxidation rates of components of the waste water and thus different respiration rates. Sludge from different sources, and/or grown under different conditions, may also vary in response to inhibitors, because of varying degrees of reaction of some inhibitors with non‐living sludge components. Therefore, in practice, it has been usual to consider EC50values from the inhibition of respiration of activated sludge test in terms of order of magnitude. Variations in EC50results of the ‘ISO’ inhibition of respiration test have been quantified for a number of chemicals, both within and between batches of sludge, and with sludges from different sources. The coefficient of variation of EC50results within batches of sludge was found to be approximately 9%. Between batch and between source variations were 28–76% depending on the te

ISSN:0884-8181    

DOI:10.1002/tox.2540010104

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

年代:1986

数据来源: WILEY

摘要:

AbstractMobile genetic elements have been found in the genomes of both procaryotic and eucaryotic organisms. Their unique capacity to move (or transpose) to new chromosomal locations has been critical to their persistence and their ability to affect gene structure and expression. It is conceivable that many physical and chemical agents may induce non‐specific DNA transpositions which can result in genomic rearrangements and mutations. We have derived a simple procedure to detect the induction of DNA transposition using bacteriophage Mu, a temperate coliphage whose 37 kilobase linear double‐stranded DNA genome behaves as a transposable element during lytic growth and lysogeny. Our assay measures the ability of a chemical to enhance or inhibit the induction of Mu DNA transposition and lytic growth. We have examined a wide variety of mutagens, carcinogens and common chemical compounds and found that most of these agents had little effect on prophage Mu induction and lytic growth at all doses tested. However, many DNA‐damaging agents showed a dose‐dependent decrease in both the number of plaque‐forming units and the number of colony‐forming units. We did find that the frequency of prophage Mu induction can be stimulated by certain amino acid analogues, notably azetidine 2‐carboxylic acid, but not by others. These results indicate that the response of mobile genetic elements to external agents is not a simple one, and may reflect the necessary presence of an element and cellular regulatory pathway to control these endoge

ISSN:0884-8181    

DOI:10.1002/tox.2540010105

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

年代:1986

数据来源: WILEY

摘要:

AbstractA method for determination of the “basic” respiration rate of soils, as the rate of O2‐consumption, has been developed. It includes standardization of both the handling of samples before determination and of the temperature and the water content at which the determination is performed. The respiration rate determined in this way varies less than normally occurs when samples of a soil are taken over a period of time. Neither the handling at sampling nor the variation in time before determination influences the result. Comparisons between a soil's respiration rate and its ability to decompose a pesticide are more easily made if the decomposition data can be expressed in mathematical form and thereby linearized. This has been done for linuron and glyphosate by plotting the decomposition data according to the formulac=co–k√tt.Good correlation between the rate of respiration and the rate of decomposition (k‐value) was found for linuron and glyphosate in laboratory experiments and also for glyphosate in field

ISSN:0884-8181    

DOI:10.1002/tox.2540010106

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

年代:1986

数据来源: WILEY

摘要:

AbstractOne of the most common ways of surface and ground water contamination from hazardous wastes is through its leachates. Toxicity is a meaningful parameter allowing an integrated evaluation of the potential danger of leachates. Two bioassays were considered for measuring toxicity: Microtox andDaphnia magna.The toxicity was measured on leachates obtained, using different leaching procedures, from wastes of a pesticide manufacturing industry and sludge from electroplating wastewater. Twenty‐two tests were carried out, measuring IC50 forD. magnaand EC50 for Microtox. Both bioassays were compared using three toxicity criteria. The first criterium is classification on toxic/non‐toxic at 25 and 50% leachate concentration. The second criterium is classification on percent ranks, and the third on log ranks. Considering these criteria, the agreement between both bioassays is within a 75–85%. It is shown that both, Microtox andD. magnaassays could be used as toxicity indicators for the wastes considered. The sensitivity of the bioassays is different depending on leachate composition. In all samples, the leachate concentration of chemicals was mea

ISSN:0884-8181    

DOI:10.1002/tox.2540010107

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

年代:1986

数据来源: WILEY

摘要:

AbstractThe response of phytoplankton communities to copper, cadmium, zinc, and pentachlorophenolate in 24‐factorial experiments were investigated. Seven experiments lasting from three to five days were carried out. During each experiment, 16 bottles were incubatedin situ.Different species had different responses to the toxicants. For evaluation of the response of the whole community the desirability function was used. The densities of abundant species in the control bottle were used as a reference and considered as desirable. All exceptions more than one standard deviation from the control were considered detrimental. The value of the overall desirability functionDwas calculated as a geometrical mean of the values of the desirability function fornsingle speciesD = (d1d2…dn)1/n.The overall desirability function values in the factorial experiments were treated by regression analyses. In all experiments, the responses of the phytoplankton community to the toxicants were similar. In general, copper caused the greatest change in phytoplankton communit

ISSN:0884-8181    

DOI:10.1002/tox.2540010108

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

年代:1986

数据来源: WILEY

摘要:

AbstractMicrocosms containing sediment and water from lacustrine, riverine and estuarine ecosystems were used to determine the rate of mineralization oft‐butylphenyl diphenyl phosphate (BPDP), a triaryl phosphate ester which is commonly used as a flame‐retardent plasticizer. Mineralization of BPDP ranged from 1.7% up to 37.2% after 8 weeks and the rate of degradation was related to the nutrient level and contaminant history of each ecosystem. Total heterotrophic populations as well as populations of microorganisms capable of utilizing BPDP as a sole source of carbon and energy varied but were greatest in sediments with higher BPDP mineralization rates. Phosphodi‐ and phosphotriesterase enzyme activities varied in each sediment according to BPDP mineralization rates. Adaptive increases in enzymatic activities and microbial populations were observed in some microcosms after exposure to BPDP. Volatile and nonvolatile organic‐solvent extractable14C‐residues were quantitated by liquid scintillation spectrometry. Extractable14C‐residues were separated by thin‐layer chromatography into polar and non‐polar compounds. Our results indicate that the rate of BPDP biodegradation varied among ecosystems and was highest in water and sediment from eutrophic ecosystems which have been previously exposed to xenobiotics. Therefore, microcosm components should be collected from ecosystems which have physical, chemical, and biological characteristics which are similar to the ecosystems most likely to be contaminated

ISSN:0884-8181    

DOI:10.1002/tox.2540010109

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

年代:1986

数据来源: WILEY

摘要:

AbstractThe unicellular freshwater algaPoterioochromonas malhamensisis presented as a screening test system for studying general and specific toxic effects of xenobiotics. The algae are grown in suspension culture in organic substrate and have various characteristics (e.g. fast growth, vegetative reproduction, mobility, etc.) which allow the detection of effects on viability and cell reproduction by light microscopical observation and counting. In addition, the cells exhibit three microtubule‐dependent processes: lorica formation, mitosis and cytokinesis. Using two light microscopical tests adapted to this system (lorica formation test and nuclear phase accumulation test) information about possible interactions of a given test compound with mitotic and/or cytoplasmic microtubules of the algae can be obtained within a comparatively short time (3 hr. and 24 hr. incubation, respectively

ISSN:0884-8181    

DOI:10.1002/tox.2540010110

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

年代:1986

数据来源: WILEY

ISSN:0884-8181    

DOI:10.1002/tox.2540010111

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

年代:1986

数据来源: WILEY