bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dehydrogenase activity of soil microflora: Significance in ecotoxicological tests
Authors: Rossel D. , Tarradellas J. 
Published: October 2006

AbstractThe dehydrogenase activity (DHA) of the microflora of a gleyic luvisol artificially contaminated by 1, 10, and 100 μg tributylin (TBT)/g dry wt soil was compared with its ATP content, long‐term CO2 evolution, and esterase activity. DHA was measured by reduction of triphenyltetrazolium chloride. This 203‐day laboratory experiment comprised a phase of air drying, a remoistening, and the addition of a substrate (alfalfa and yeast extract). The half‐life of TBT ranged from 40 (10 and 100 μg/g) up to 70 days (1 μg/g).The microflora was not affected by 1 and 10 μg TBT/g. After an initial 60% stimulation, the respiration and esterase activity in the soil contaminated by 100 μg TBT/g recovered to the level of the control soil in 2 and 14 days, respectively. About 50% depression of DHA and ATP content was observed throughout the 203 days of the experiment. DHA inhibition was correlated with depression of ATP content (r = 0.82). Air drying, remoistening, and substrate addition had little influence on the depression of DHA and of the ATP content.Unlike long‐term CO2 evolution, DHA did not reflect the total effective activity of soil microflora; rather, it reflected its total potential activity. As for biomass estimates using substrate‐induced respiration, a clear distinction should be made between short‐term DHA and other measurements of DHA. Short‐term DHA, as a substrate‐induced maximum initial activity, appears mainly to reflect the biomass of soil microflora. The measurement of DHA appears to be a suitable low‐cost and sensitive tool for assessing side effects of chemicals.
Microbiotests in aquatic ecotoxicology: Characteristics, utility, and prospects
Authors: Blaise Christian 
Published: October 2006

AbstractSmall‐scale biological tests (microbiotests) have steadily increased in development and application over the last 30 years in the field of aquatic ecotoxicology. Multitrophic level assessment requirements, attractive features of microbiotests, and the constant search for simplicity and cost efficiency of testing are reasons explaining the expanding use of microbiotests. In this article, the major characteristics that advantageously confer popularity on microbiotests are presented and 25 currently applied aquatic toxicity microbiotests are listed. Conducted with bacteria, protozoans, microalgae, small invertebrates, and fish cell lines, these microbiotests represent a realistic cross section of those that are now becoming an essential part of ecotoxicological assessment. Microbiotests can be profitably employed for ranking and screening chemicals, for novel applications enabling rapid detection of ecotoxic effects in complex liquid samples, and for increasing the cost efficiency and diagnostic potential of hazard assessment schemes. Microbiotesting research, development, and applications will continue to surge in the 1990s, driven, among other factors, by the imperative need for cost effectiveness in environmental programs. Research in the fields of ecotoxicology, biotechnology, and immunochemistry should provide interesting breakthroughs to further enhance the specificity and diagnostic value of microbiotests.
Desulfovibrio desulfuricans growth kinetics
Authors: Herrera L. , Hernández J. , Ruiz P. , Gantenbein S. 
Published: October 2006

AbstractGrowth kinetics of Desulfovibrio desulfuricans, strain NCIMB 9467, was studied in laboratory scale, under well‐controlled batch conditions. This research is oriented toward the practical, industrial removal of sulfate and metal ions from mine water. Growth of the microorganism in such waters was verified.From 290 experimental observations of sulfate and lactate (obtained from 145 culture tubes of 20 mL) the parameters of a Monod model were estimated. Inoculum mass was not measured but it was incorporated as another model parameter. Hydrogen sulfide was removed by addition of ferrous iron, which rapidly formed iron sulfide and precipitated toward the bottom of the culture tube. Parameters were estimated by a nonlinear least squares parameter minimizer. The growth‐limiting substrate was the sulfate concentration. Under these conditions the growth of Desulfovibrio desulfuricans was characterized by a maximum growth rate of 25 · 10−3 h−1, a sulfate affinity constant of 850 mg L, and a reduced sulfate yield of 6.2 · 10−3 (biomass per sulfate mass). Inoculum was 1.97 mg of bacteria/L and the consumption of lactate was characterized by a yield of 2.5 · 10−2 (biomass per lactate mass). Sulfate was reduced at a rate of 400 mg/L/day while lactate was oxidized at a rate of 1100 mg/L/day.Mine wastewater was used as sulfate source and complemented with lactate as the carbon source. Under these conditions the strain growth was similar to that obtained with the controlled media. It was concluded that no inhibitory effects exist. The reduction velocity obtained, 200 mg/L/day, was lower than before, probably due to inoculum size or strain adaptation.A novel process is proposed to produce solid sulfur from sulfate and sulfur oxides.
Characterization of aerobic heterotrophic bacteria isolated from marshes
Authors: Horsnell G. E. , Young M. , Pagel J. E. , Desjardins R. M. , Seyfried P. L. 
Published: October 2006

AbstractAn organized approach, requiring a minimum number of tests, is presented for the relatively rapid identification of a wide range of aerobic heterotrophic bacteria found in freshwater. Bacterial isolates were identified to the genus level and many strains could be identified to the species level with the appropriate use of commercially available bacterial identification panels.Bacteria were separated into four groups based on gram reaction, motility, cell shape and arrangement, spore and pigment production, catalase, oxidase, and O/F glucose tests. Further identification was based on selected tests for each group.Over 95% of the 800 aerobic heterotrophic bacteria isolated from Ontario marshes were identified using the procedures outlined.
Regulatory influence of light and temperature on petroleum toxicity to Anabaena doliolum
Authors: Gaur J. P. , Singh A. K. 
Published: October 2006

AbstractEffects of light and temperature, the most important variables in natural environments, on the toxicity of Assam crude oil extract were examined. Illumination of oil extract increased the degree of inhibition of growth, photosynthesis, and respiration of Anabaena doliolum. Higher light intensities were more effective in inhibiting the test organism. This may result from the formation of highly toxic photooxidation products. The toxicity of oil extract also showed an increase with increase in temperature, even though it might be envisioned that elevated temperature would facilitate the loss of highly toxic volatile fractions. It is possible, therefore, that the toxic effects of petroleum might be more severe in tropical than in temperate climates.
Ecological effects testing under the Toxic Substances Control Act: Acrylamide
Authors: Walker John D. 
Published: October 2006

AbstractAnalysis of acrylamide aquatic toxicity data submitted under section 4 of the Toxic Substances Control Act revealed that for acute toxicity studies with bluegill, fathead minnow, and rainbow trout, concentrations of acrylamide necessary to produce 50% mortality decreased by 50‐70% as a function of increasing exposure from 1 to 4 days. Analysis of acute toxicity data for Mysidopsis bahia suggested that increases in mortality with increased exposure to acrylamide might also be observed in saltwater organisms. Ratios of acute (4‐day) LC50 values to chronic (28‐day) maximum acceptable toxic concentrations for this saltwater invertebrate were 26 for parent and offspring survival, 115 for female dry weights, and 975 for male dry weights. These ratios illustrate that long‐term acrylamide exposure to sensitive life stages of M. bahia produced adverse effects on reproduction and growth at acrylamide concentrations significantly lower than those suggested by acute LC50 or EC50 values.
Microtesting appraisal of ATP and cell recovery toxicity end points after acute exposure of Selenastrum capricornutum to selected chemicals
Authors: Hickey C. W. , Blaise C. , Costan G. 
Published: October 2006

AbstractEmploying microtesting procedures, intracellular ATP and cell recovery (96‐h cell count determinations) were appraised as toxicity end‐point responses after acute (4‐h) exposure of the green alga Selenastrum capricornutum to metals (Cu2+, Co2+, Cd2‐, Cr3+, Cr6+, Ni2+, Hg2+, Zn2+, B3+), sodium azide, and 4 organic compounds (sodium dodecyl sulphate, 2,4‐dichlorophenol, phenol, tebuthiuron). Except for B3‐, both end points were able to measure acute metal phytotoxicity effects at concentrations of 5 mg · L−1 or lower. The algal recovery test showed better metal toxicity discrimination than the ATP test on the basis of dose—response slope steepness and elevation differences. Both tests, however, supplied useful complementary information. While the ATP test reacted rapidly to chemical aggression, the recovery test offered pertinent insight into actual long‐term consequences of acute exposure. With the nonmetals, both end‐point responses were mitigated (sodium azide, sodium dodecyl sulphate, 2,4‐dichlorophenol) or insensitive (phenol, tebuthiuron), suggesting low acute exposure risk to algae by these chemicals. Based on 4‐h (ATP and cell recovery) EC50 to standard 96‐h EC50 ratio values, the algal indicator was shown to have low tolerance to 6 chemicals (Cr3+, Cr6+, Hg2‐, Cu2+, sodium dodecyl sulphate, 2,4‐dichlorophenol). When compared to acute exposure bacterial assays, the acute exposure ATP and cell recovery microtests competed well in terms of overall sensitivity to a selection of chemicals. In general, this work demonstrates the utility that short‐term algal exposure tests can provide for chemical toxicity investigations.
Acute toxicity of Phytolacca dodecandra (Endod‐S) and Niclosamide to snails, Schistosoma mansoni cercaria, Tilapia fish, and soil microorganisms
Authors: Monkiedje Adolphe , Anderson Ann C. , Englande A. J. 
Published: October 2006

AbstractThe acute toxicity of two molluscicides, the extract of the plant Phytolacca dodecandra (Endod‐S) and Niclosamide, was determined using the following test species: The snails Biomphalaria glabrata (albino) and Biomphalaria pfeifferi, Schistosoma mansoni cercaria, and Tilapia nilotica fish. Endod‐S showed a 24‐h LC50 of 2.57 and 5.37 mg/L for B. glabrata (albino) and B. pfeifferi respectively. Niclosamide produced a 24‐h LC50 of 0.063 mg/L and 0.049 mg/L for B. glabrata (albino) and B. pfeifferi, respectively. The 4‐h LC50 for S. mansoni cercaria was 2.92 mg/L for Endod‐S and 0.0008 mg/L for Niclosamide. The 24‐h LC50 for Tilapia nilotica was 1.82 mg/L for Endod‐S and 0.21 mg/L for Niclosamide. The toxicity of Endod‐S and Niclosamide to a mixed population of soil microorganisms was measured using oxygen uptake and growth as measured by turbidity. Endod‐S was not toxic to the microorganisms. The average Niclosamide toxic end point (IC50) for these bacteria was 450 mg/L.
Wastewater upgrading as measured by coliphage
Authors: Kott Yehuda 
Published: October 2006

AbstractBacterial viruses are prevalent in nature. The coliphage counts in any wastewater sample might show very significant diversity in numbers, due to use of various Escherichia coli strains. In this study coliphage (E. coli B host) coliform, fecal coliform, and fecal streptococci densities were estimated from chlorinated secondary effluent being carried in a 30‐km long pipeline. Comparison of die‐off of the various indicators was performed between controlled and uncontrolled chlorination at slow and fast flow in the pipe. In addition, a swab technique was applied from which a rough estimation of the ratios of coliphage to the other indicators could be made, as well as coliphage to salmonella ratio. The results showed that there was a decrease in coliphage number at higher levels of chlorine residual, and wherever aftergrowth of coliform occurred, the number of coliphage did not change.
Genotoxicity of hazardous leachates from solid wastes evaluated for environmental impact with the ames test
Authors: Bessi H. , Ferard J. F. , Vasseur P. , Colin F. , Belkhadir E. 
Published: October 2006

AbstractFourteen series of toxic wastes from various origins (metallurgy, chemical industries, incinerators, industrial treatment plants, etc.) have been studied for their genotoxic properties with the Salmonella reversion assay. To consider realism of environmental impact, a strategy is proposed to assess genotoxicity of the water‐soluble fraction of the wastes. Water‐extractable micropollutants were further concentrated by liquid–liquid extraction or lyophilization prior to genotoxicity testing.None of the 14 crude aqueous fractions was shown to be mutagenic. On the contrary, positive responses were registered on the concentrated phases of two solid wastes derived from one chemical industry and from the treatment of organophosphorus wastewaters. Chemical analysis did not reveal the presence of known mutagens in the positive extracts. Interacting effects between micropollutants is thus hypothesized to explain genotoxicity.
Biodegradation of pentachlorophenol by micromycetes. I. Zygomycetes
Authors: Seigle‐Murandi Francoise , Steiman Regine , Benoit‐Guyod Jean‐Louis , Guiraud Pascale 
Published: October 2006

AbstractA study of the biodegradation of pentachlorophenol (PCP) (100 mg/L) by 70 strains of Zygomycetes cultivated in liquid synthetic medium showed that most strains were able to degrade it extensively, except some from the genera Circinella, Mortierella, Mucor, and Spinellus. The most consistently effective genera were Absidia (degradation 69–88%) and Cunninghamella (degradation 62–90%). Much more scattered results were found with the genera Mortierella (degradation 0–67%), Mucor (degradation 18–86%), and Rhizopus (degradation 45–91%). The production of extracellular phenoloxidases was examined on solid media. Most of the strains were devoid of any phenoloxidase activity. The biodegradation of PCP did not depend on the presence of phenoloxidases since strains with a high level of phenoloxidases did not degrade PCP and the best degradation was obtained with strains devoid of phenoloxidases. Another mechanism must be proposed to explain the high biodegradation potential of Zygomycetes for PCP.
Effect of test conditions and interfering factors on sensitivity of bacterial tests based on inhibition of growth and motility
Authors: Süssmuth R. , Lenz P. , Müller D. 
Published: October 2006

AbstractThe effect of test conditions on the sensitivity of the swarming activity of Proteus 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, Inc.
Resistance to antibiotics and heavy metals in escherichia coli from marine fish
Authors: Alves De Lima E Silva Agostinho , Hofer Ernesto 
Published: October 2006

AbstractEscherichia coli isolated from the intestinal tract of marine fish captured along polluted beaches of the city of Rio de Janeiro, Brazil, were investigated in terms of resistance to seven antibiotics and to four heavy metals. Approximately 40% of the strains were resistant to one or more antibiotics, with predominance of mono‐ and biresistance. Overall resistance to heavy metals was 70.7%, and exclusive resistance to these elements was more elevated than resistance to antibiotics only. Resistance to mercury was closely associated with resistance to antibiotics and with multiple resistance in particular. Most of the strains analyzed transferred resistance determinants to standard receptor strains during conjugation, the phenomenon being particularly outstanding for the transfer of the copper marker. The epidemiological and ecological aspects of the results obtained are discussed. © 1993 John Wiley & Sons, Inc.
Virulence characteristics of heterotrophic bacteria commonly isolated from potable water
Authors: Lye Dennis J. , Dufour Alfred P. 
Published: October 2006

AbstractHeterotrophic bacteria isolated from drinking water distribution systems were examined to determine if they possessed putative virulence factors such as hemolysins, proteases, or cytotoxins. Representative samples of colonies from several different distribution systems indicated that the median percentage of heterotrophic bacteria having at least one putative virulence characteristic was about 11% and all of the samples contained bacteria expressing at least one putative virulence characteristic. The overall frequency of bacteria from drinking water distribution samples expressing more than one putative virulence factor ranged from 0 to 8%. The eukaryotic cell culture cytotoxicity test appeared to be the most reliable indicator of those bacteria expressing multiple virulence factors. The results also indicated that the expression of putative virulence factors was highly dependent upon the type of isolation medium used. Although slow‐growing heterotrophic bacteria occurred at high densities in certain systems, they expressed very few of the putative virulence factors observed in this study. © 1993 John Wiley & Sons, Inc.
Sensitivity of planktonic photosynthesis to various toxicants in the river rhine
Authors: Tubbing Diny M. J. , De Ruyter Van Steveninck Erik D. , Admiraal Wim 
Published: October 2006

AbstractNatural populations of phytoplankton from the lower River Rhine were exposed to selected pollutants in order to estimate their sensitivity to chemical pollution. The photosynthesis, measured as 14C incorporation, was inhibited by 50% when circa 100 μg · L−1 copper or atrazine was added. Potassium dichromate (K2Cr2O7) and an anionic detergent (tetrapropylbenzenesulphonate) affected the photosynthesis of Rhine phytoplankton only at concentrations of about 3 and 40 mg L−1, respectively. A tenfold concentrate of the organic compounds from river water, harvested on XAD resin, inhibited the photosynthesis by 50%. Comparison of the results of this study with literature data indicate that the algal populations in the River Rhine are as sensitive and not more tolerant than several algae from less polluted habitats. These observations on the Rhine plankton also indicate that the pollution level in the River Rhine is likely to affect the photosynthesis of phytoplankton. This supports the request for a further reduction in toxicant input in the River Rhine. © 1993 John Wiley & Sons, Inc.
Potential ecotoxic effects probe (PEEP): A novel index to assess and compare the toxic potential of industrial effluents
Authors: Costan G. , Bermingham N. , Blaise C. , Ferard J. F. 
Published: October 2006

AbstractAn index allowing the assessment and comparison of the toxic potential of industrial effluents is described. Integrating the results of practical small‐scale screening bioassays (Photobacterium phosphoreum Microtox® test. Selenastrum capricornutum growth inhibition microtest, Ceriodaphnia dubia lethality and reproduction inhibition tests, Escherichia coli genotoxicity SOS Chromotest), this index takes into account persistence of toxicity, (multi) specificity of toxic impact, as well as effluent flow. The resulting Potential Ecotoxic Effects Probe (PEEP) index number is reflected by a log10 value that varies from 0 to infinity but normally will not surpass a value of 10. The structure of the mathematical formula generating PEEP values is simple and “user friendly” in that it can accommodate numbers and types of bioassays to fit particular needs. Thirty‐seven effluents from 8 industrial sectors (pulp and paper, petroleum refining, inorganic/organic chemical production, mining, metallurgy, metal plating, textile production) were appraised and compared with the proposed PEEP scale. The pulp and paper sector effluents (n = 15) markedly stood out from the others owing to their greater toxicity and higher discharge volume, with reported PEEP values lying between 4.4 and 7.5. For most of these effluents, toxicity was found to be persistent, multitrophic (i.e., affecting our bacterial, algal, and crustacean bioindicators), and it expressed itself at all levels of assessment (i.e., lethal, acute sublethal, chronic sublethal, and genotoxic levels). The usefulness of the PEEP index in the environmental management of industrial effluent toxicity is discussed herein. © 1993 John Wiley & Sons, Inc.
Biological and chemical aspects of differences in sensitivity of natural populations of aquatic bacterial communities exposed to copper
Authors: Tubbing Diny M. J. , Santhagens Linda‐Rose , Admiraal Wim , Van Beelen Patrick 
Published: October 2006

AbstractBacterial populations from the main stream of the River Rhine and its plume in the North Sea, the lower course of the rivers Meuse and Scheldt, and various stagnant waters in the Netherlands were exposed to additions of copper in order to analyze differences in sensitivity. Growth rate, measured as thymidine incorporation rate, was generally more sensitive to copper (EC50: 25–310 μg · L−1) than extracellular phosphatase activity, measured as hydrolysis of methylumbelliferin phosphate (EC50: 179–3000 μgl−1). The EC50 value for copper‐inhibited growth was correlated with the ambient total copper concentration, but such a correlation was not evident for copper‐inhibited enzymatic activity. Differences in capacity of the waters to chelate an addition of 1000 μg L·−1 of copper were estimated by measuring the inhibition of Photobacterium phosphoreum in the Microtox test. The growth rate of bacteria in the upper, middle, and lower courses of the Rhine showed an increasing tolerance to copper, concurrent with increased input of copper and increasing concentrations of suspended matter in the river. It is indicated in this study that part of the differences in sensitivity of bacterial communities is caused by the chemical conditions (i.e., by complexation), but biological differences in tolerance to copper, possibly induced by pollution, were also indicated. © 1993 John Wiley & Sons, Inc.
Direct toxicity assessment of solid phase samples using the toxi‐chromotest kit
Authors: Kwan K. K. 
Published: October 2006

AbstractToxicity screening of sediments, suspended sediments, soils, and solid wastes is becoming increasingly important in environmental studies. To date toxicity testing of sediments, suspended sediments, soils, and solid wastes has almost always been performed on exudates, water, and/or solvent extracts. These procedures are often complicated, labor intensive, and expensive. This report describes a simple, quick, inexpensive qualitative/ semiquantitative direct sediment/solid phase toxicity testing procedure (DSTTP) using the Toxi‐Chromotest kit. This procedure only requires the use of a balance, vortex mixer, and a 37°C incubator, and can easily be used under field conditions. The DSTTP measures the available toxicants of the test sediments, suspended sediments, soils, and any other solid wastes without altering the original characteristics of the samples as occurs in extraction and concentration procedures. © 1993 John Wiley & Sons, Inc.