摘要:

AbstractOwing to Cyanophytes, toxic blooms may originate in drinking water supplies. Since it is vitally important for human health that such blooms are rapidly identified and treatment plant for water potabilization is readily adapted, we have performed experiments aiming at assessing the usefulness of Microtox™ as a tool for detecting biotoxins caused by Cyanobacteria as rapidly as possible. Comparison between instrumental results and data obtained with Microtox has shown a discrepancy, but has also pointed out Microtox's sensitivity and therefore its application in monitoring Cyanophyte blooms in order to detect algal biotoxins, whose chemical characterization requires further examination following identification by the Microtox syste

ISSN:1053-4725    

DOI:10.1002/tox.2530070302

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

年代:1992

数据来源: WILEY

摘要:

AbstractThe herbicide glyphosate (Roundup) was applied aerially to a conifer forest that had previously been clear‐cut and reforested. Glyphosate was tested for effects on microbial biomass, numbers of selected microorganisms, and soil respiration over a period of 8 months by comparing treated and untreated zones of the clay loam forest soil (FS) and the overlying litter (FL), both pH 3.8. With microbial biomass, glyphosate generally had a stimulatory effect in FL, but usually no significant effect in FS. Glyphosate had no significant effect on numbers of bacteria, fungi, and actinomycetes in either FL or FS. The herbicide generally stimulated respiration in both FL and FS. In laboratory bioassays using FL, FS, and three agricultural soils, glyphosate had no significant effect on respiration when used at concentrations up to 100 times higher than recommended field application rates. Respiration rates in FL, as measured with Warburg respirometry, were unaffected by glyphosate. Respiration rates in FS were stimulated by glyphosate concentrations 10 and 100 times higher than recommended field rates. Glyphosate should have no deleterious effects on microbial biomass and respiration in forest soils when used under recommended conditions. © 1992 John Wiley&sons, I

ISSN:1053-4725    

DOI:10.1002/tox.2530070303

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

年代:1992

数据来源: WILEY

摘要:

AbstractSix Cd‐resistant bacterial strains were isolated from a soil receiving dredged sediments and containing Cd at concentration of 50 mg kg−1. The isolates, identified as gram‐positive, were studied with regard to their ability to tolerate and accumulate Cd at concentrations varying from 0 to 100 mg L−1. Results showed an increase in accumulated Cd in bacteria with increasing Cd concentrations in solution. Isolates were shown to tolerate higher Cd concentrations than aBacillus subtilisstrain used as a control. One of the isolates, identified asBacillus brevis, was found to be the most resistant to Cd, with an ability to accumulate the toxic metal up to 70 mg−1of cells (dry weight). Mn was found to reduce Cd toxicity and accumulation inB. brevis. This strain may have some potential interest in reclamation of metal‐contaminated soils. © 1992 John Wil

ISSN:1053-4725    

DOI:10.1002/tox.2530070304

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

年代:1992

数据来源: WILEY

摘要:

AbstractSuspended aggregates from the Yamaska River in Quebec have been separated into several fractions from 3 to<88 μm using size fractionation technique, and these fractions were analyzed for their bacterial, particulate organic carbon and nitrogen content, as well as their ability to adsorb two water‐soluble dyes. The results indicate that the suspended bacterial aggregates are capable of adsorbing and thus transporting significant quantities of these dyes in river water. The maximum contaminant dye adsorption occurred within the 24‐h period for Acid Orange 60. Implications of bacterial‐mediated contaminant transport in aquatic environments are indicated. © 1992 John Wiley&So

ISSN:1053-4725    

DOI:10.1002/tox.2530070305

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

年代:1992

数据来源: WILEY

摘要:

AbstractThe effect of test conditions on the sensitivity of the swarming activity ofProteus mirabilis and Azospirillum brasilense, of the cup plate assay (Bacillus thuringiensis), and of a cell counting assay in liquid medium using a Coulter Counter (B. thuringiensis) was studied. Tested substances were pesticides, mycotoxins, lactones, and anhydrides. Sensitivity was increased by cell counting (up to 1000‐fold), by variation of nutrient concentration and pH in the culture medium, by density of inoculum, by preincubation at 4 or 44°C, by incubation with a detergent, and by the use of sensitive mutants. Interferences were exerted by certain substances and toxin mixtures. They included synergistic and antagonistic effects as well as oscillations, e.g., concentration‐dependent activation and inactivation. © 1992 John Wiley&sons

ISSN:1053-4725    

DOI:10.1002/tox.2530070306

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

年代:1992

数据来源: WILEY

摘要:

AbstractThe literature offers conflicting information on the phytotoxicity of uranium (U) in soil. Levels as low as 5 mg U/kg soil, well within the normal background range, have been cited as toxic, whereas many studies report no toxicity at levels 100‐ to 1000‐fold higher. Uranium in soil does not often present a radiological hazard to humans, but toxicity to plants could lead to prescribed cleanup and assessment criteria for industrial activities. This study was designed to identify the toxic threshold of soil U. Nine levels of U were added to background‐level soils. Beans were grown to maturity in an outdoor lysimeter study with 2 soils. Germination tests in the growth chamber were done with 11 soils and with 5 plant species. A rapid cyclingBrassica rapacultivar, proposed as a new toxicity test subject, was grown to maturity on 2 soils in the growth chamber, and germination of the second‐generation seeds was investigated. Earthworm survival and soil phosphatase activity were measured. Measures of soil‐extractable and tissue U concentrations were obtained. None of the measurements indicated detrimental effects of U below 300 mg/kg. In one of the soils,B. rapaproduced seed at concentrations as high as 10,000 mg U/kg. The phytotoxicity of U occurred at concentrations 8‐ and 3‐fold higher than the concentrations of As and Zn, respectively, which gave the same effect. © 1992 John W

ISSN:1053-4725    

DOI:10.1002/tox.2530070307

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

年代:1992

数据来源: WILEY

摘要:

AbstractInvestigations were conducted to compare the efficiency of adenosine triphosphate (ATP) extraction from freshwater zooplankton species (Skistodiaptomus oregonensis, Tropocyclops prasinus mexicanus, Daphnia magna, and Bosmina longirostris) using DMSO and cold H2SO4extraction procedures. DMSO was found to extract more ATP (particularly in copepod species) while cold H2SO4provided more consistent results. Homogenization by grinding samples during extraction was shown to be a very important step. Juvenile and adult specimens ofD. magnawere extracted. Adults gave higher ATP values. The necessity for a 24‐h acclimation period was tested. Although acclimation appeared to provide more consistent results, no marked lowering of ATP level in organisms was registered without acclimation. No unique method was found to be optimal for all studied species. © 1992 John Wiley&sons, I

ISSN:1053-4725    

DOI:10.1002/tox.2530070308

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

年代:1992

数据来源: WILEY

ISSN:1053-4725    

DOI:10.1002/tox.2530070301

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

年代:1992

数据来源: WILEY