bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bioassessment of water quality
Authors: Wong P. T. S. , Dixon D. G. 
Published: October 2006

AbstractOver the past 20 years there has been a concerted effort to define and limit the impacts of anthropogenic contaminants in aquatic environments. There are essentially two philosophies that can be employed to regulate and to assess the effects of toxic chemicals in these systems. The first is the water quality objectives research. Under this protocol, laboratory research is used to set an objective, the concentration of a substance or condition that is considered to have no effect on the organisms in an aquatic environment based on a review of the pertinent research. The second approach, environmental health assessment, uses the in situ responses of free‐living organisms in contaminated environments to determine the overall impacts of the environment on those organisms. In this review paper we will attempt to compare and contrast the advantages and disadvantages of the two approaches, and to outline a system whereby they can be used together to enhance our degree of confidence in legislation directed at reducing contaminant impacts. ©by John Wiley & Sons, Inc.
A review of the aquatic ecotoxicology of polychlorinated dibenzo‐p‐dioxins and dibenzofurans
Authors: Grimwood Mark J. , Dobbs Tony J. 
Published: October 2006

AbstractThis paper reviews published studies on polychlorinated dibenzo‐p‐dioxins and polychlorinated dibenzofurans that are relevant to an assessment of their aquatic ecotoxicology. The available data suggest that laterally substituted congeners containing altogether 4,5, or 6 chlorine atoms are highly toxic, particularly to the early life stages of fish, with reported effect concentrations in the ng L1 range. These congeners are also the most readily bioaccumulated.An aquatic toxicity threshold concentration of 0.011–0.038 ng L−1, applicable to natural ecosystems, was determined for 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin (or for mixtures of congeners expressed as 2,3,7,8‐TCDD equivalents). This threshold corresponds to the no observed effect concentration/lowest‐observed effect concentration determined for mortality, growth, and behavioral effects seen in rainbow trout early life stages, exposed to 2,3,7,8‐TCDD in a flow‐through system over a 28‐day period, followed by 28 days of depuration.An investigation was also made into the potential for using mammalian‐derived toxic equivalency factors (TEFs) in aquatic ecosystems. This revealed that such an approach may underestimate the aquatic toxicity of some congeners, and that the use of organism‐specific TEFs may be more appropriate. © by John Wiley & Sons, Inc.
Bioassay assessment of impacts of tar sands extraction operations
Authors: Dutka B. J. , Bourbonniere R. , McInnis R. , Kwan K. K. , Jurkovic A. 
Published: October 2006

AbstractThis report describes the application of ten bioassays (battery of tests approach) to waters and sediments collected from the tar sands area of northern Alberta, Canada. In this study there were three main goals: (1) to establish the presence and sources of toxicants in these northern waters and sediments, (2) to determine if their presence is related to sediment composition, and (3) to establish which of the various sediment extracting procedures used was most efficient in producing responses in the bioassays used.Results of these investigations indicated that there were two obvious sources of toxicants/genotoxicants, the tar sands extracting area and streams passing through tar sands or oil shales and at least two unknown sources. Based on the techniques used in this study, there does not appear to be a strong sediment structure–toxicant response relationship. Extraction procedure results were variable and are discussed in detail in the report. © by John Wiley & Sons, Inc.
Biodegradation of the herbicides 2,4‐dichlorophenoxyacetic acid, 2,4,5‐trichlorophenoxyacetic acid, and 2‐methyl‐4‐chlorophenoxyacetic acid in a sulfate‐reducing aquifer
Authors: Kuhlmann Birgit , Kaczmarzcyk Barbara 
Published: October 2006

AbstractBiodegradation of trace organic compounds is one of the main mechanisms to purify infiltrating surface water during bankfiltration and underground passage. In anaerobic zones of the underground, rate and extent of degrading processes may be totally different from those in aerobic ones. To investigate this, a model ecosystem was built that reproduces an anaerobic part of the aquifer and the behavior of the three phenoxyacetic acid herbicides 2,4‐dichlorophenoxyacetic acid, (2,4‐D), 2,4,5‐trichlorophenoxyacetic acid (2,4,5‐T), and 2‐Methyl‐4‐chlorophenoxyacetic acid (MCPA) tested. In anaerobic experiments with varying conditions they proved to be almost persistent. Only under aerobic conditions could biodegradation be observed after a lag period. © by John Wiley & Sons, Inc.
Ecotoxicological evaluation of contaminated soil using the legume root nodule symbiosis as effect parameter
Authors: Wetzel Astrid , Werner Dietrich 
Published: October 2006

AbstractThe legume root nodules are the site of biological nitrogen fixation in the legume—rhizobium symbiosis. They are a structure unique to this symbiosis and morphologically as well as physiologically distinct from other plant organs. We will present evidence that the formation of nodules (nodulation) may serve for ecotoxicological evaluation of contaminated soil. Substances affecting the macro‐ and/or microsymbionts vitality, such as certain heavy metals or polycyclic aromatic hydrocarbons (PAHs), reduce nodulation before visible damage of the plant occurs. Tests were performed in petri dishes that were planted with alfalfa seedlings and inoculated with Rhizobium meliloti. Mineral agar served as substrate. Test substances were added to the mineral agar before pouring it into petri dishes (application of heavy metals), or were sprayed as etheral solutions onto the surface of solidified medium (application of PAHs). For investigation of contaminated soil, the soil material was first mixed with mineral agar and then poured into petri dishes. Appropriate controls were made by extracting an aliquot of soil with methylene chloride to remove hazardous substances. Data from stressed plants were taken after 15 days of cultivation on contaminated substrate. A dose‐responsive decrease in nodulation was found after application of CdCl2, NaAsO2, fluoranthene, and other PAHs. PAH‐contaminated soil (75 mg/kg) caused only a slight reduction in nodulation of alfalfa. But when PAHs were extracted and restored into the extracted soil material, toxicity and uptake of PAHs into roots and shoots dramatically increased. Toxicity and uptake of PAHs were also enhanced by reducing the amount of humic matter added to the test system. © by John Wiley & Sons, Inc.
Precautions for routine use of INT‐reductase activity for measuring biological activities in soil and sediments
Authors: Merlin G. , Lissolo T. , Morel V. , Rossel D. , Tarradellas J. 
Published: October 2006

AbstractTo evaluate toxicity of xenobiotics on microflora of soils and sediments, reduction of tetrazolium dye [2‐p‐iodophenyl‐3‐p‐nitrophenyl‐5‐phenyltetrazolium chloride (INT) or 2,3,5 triphenyltetrazolium chloride (TTC)] by dehydrogenase activities is commonly used, but many questions are posed about the biological relevance of this test.In this work, INT was chosen to evaluate the influence of some experimental factors on reductase activity. INT adsorption to soil, concentration of INT, and sterilization methods were tested on different soils and sediments to determine bioavailability of INT, saturation concentration, and intensity of chemical reduction.INT adsorption shown dramatic variations vs type of soil, from 0 to 100%, and was particularly linked with cation exchange capacity.Formaldehyde seems to be the best method with irradiation to determine abiotic reduction, particularly with sediments.However, it must be stressed that the tetrazolium reduction in microbial systems can be carried out by other enzymatic systems than malate dehydrogenase. INT is an excellent substrate of membrane hydrogenases found in numerous anaerobic bacteria. This was observed with experiments conducted with Rhodobacter capsulatus in our laboratory. © by John Wiley & Sons, Inc.
Direct sediment toxicity testing procedure using sediment‐chromotest kit
Authors: Kwan K. K. 
Published: October 2006

AbstractA semiquantitative direct sediment toxicity testing procedure using the Sediment‐Chromotest was developed. This procedure has advantages over many other toxicity bioassays. It is simple, quick, and reliable, and does not require special instrumentation.The direct sediment toxicity testing procedure involves the use of serial dilutions of solid phase suspensions mixed with stressed bacteria (Escherichia coli) and a cocktail containing the specific inducer for the chromogenic enzyme and other essential factors. The assay is based on the ability of toxicants to inhibit the de novo synthesis of an inducible enzyme, beta‐galactosidase. The amount of de novo synthesized enzyme is determined by a colorimetric reaction.This new procedure measures the presence of bioavailable toxicants in sediments, suspended sediments, soils, and other solid wastes directly without extraction and concentration. © by John Wiley & Sons, Inc.
Testing of chlorinated solvents on microfungi
Authors: Steiman R. , Seigle‐Murandi F. , Guiraud P. , Benoit‐Guyod J.‐L. 
Published: October 2006

AbstractIn order to avoid the use of a sophisticated method for the determination of 3 volatile solvents (dichloromethane, tetrachloroethylene, and perchloroethylene) in the atmosphere, an alternative method was tentatively developed for the evaluation of their toxicity toward micromycetes isolated from the biological communities present in the sediments of aquatic microcosms. Survival of the microorganisms was determined by establishing the minimum lethal time50 at saturation in a vessel saturated with vapors. The method allows one to look for the development of an induction or a sensitization and can be used for any other volatile xenobiotic. © by John Wiley & Sons, Inc.
Genotoxicity of some wastewaters in India
Authors: Malik Abdul , Ahmad Masood 
Published: October 2006

AbstractHeavy metal concentrations in wastewaters from the industrial estate of Aligarh city (U.P.) India were determined. The analysis of test samples revealed significantly higher levels of Fe, Zn, Cu, Cr, and Ni compared with the pure domestic samples. Raw wastewaters were screened for mutagenic potential using the Ames Salmonella/microsomal test. Mutagenic activity was observed with industrial as well as domestic waste samples. Salmonella typhimurium strains TA102 and TA104 were the most sensitive both in the absence and presence of S9 fraction. A significant decrease in the survival of DNA repair defective Escherichia coli mutants recA, lex A, and polA was observed as compared to their wild‐type counterparts in the presence of wastewater. © by John Wiley & Sons, Inc.
A test battery of bacterial toxicity assays and comparison with LD50 values
Authors: Lenz P. , Süssmuth R. , Seibel E. 
Published: October 2006

AbstractThe toxicity of some mycotoxins, lactones and dicarboxylic anhydrides, insecticides, herbicides, and fungicides can be detected by means of bacterial assays. In addition, the order of magnitude of the toxicity can also be evaluated.Fifty‐eight chemicals as well as extracts of peanuts, apple juices, and grains have been investigated in a test battery of three different kinds of assays. In cup plate diffusion assays a minimal amount of approximately 0. 1 mg/mL of mycotoxin may be detected by means of growth inhibition assays with Bacillus thuringiensis on one hand, and pigment synthesis inhibition assays with mutants of Serratia marcescens on the other hand. Swarming inhibition assays with the motile strains Azospirillum brasilense and Proteus mirabilis show the same sensitivity. Comparisons of our test battery with other bioassays, as well as with mammalian toxicity tests (LD50 values), reveal correlations between these kinds of assays in regard to the test substances.
Biodegradation of pentachlorophenol and its commercial formulation
Authors: Liu D. 
Published: October 2006

AbstractBiodegradation processes for pentachlorophenol (PCP) and a commercial PCP formulation were evaluated to delineate factors limiting the rate of PCP degradation in the aquatic environment. Analyses of the data on PCP disappearance and chloride ion release, as well as gas chromatography and UV‐VIS (ultra‐violet and visible spectroscopy) spectra of the fermentor broth strongly indicate that the bacterial culture acted on PCP by completely stripping off all the chloride ions from a molecule of PCP, rather than following the normal pattern of removing only one chloride ion at a time. The haloaromatic ring structure of PCP was completely broken down, and not channeled into the unproductive meta‐cleavage pathway. Despite repeated transfers of the bacterial culture, an initial lag phase in PCP biodegradation was apparent in all experiments and was followed by a steady state, nearly linear rate of PCP degradation. Thus in the aquatic environment the biodegradation rate of a persistent contaminant is more likely to be regulated by whether or not this compartment has been previously subjected to a long or continuous exposure to a particular chemical. First‐order kinetics alone cannot be used to predict accurately the fate of a persistent chemical in the environment, because of the inability of such a simple equation to accommodate the effects of rate‐limiting factors such as the length of adaptation period on the overall biodegradation rate of a contaminant. For this reason, factors that may influence a chemical's biodegradability in the natural environment must be considered in the design of laboratory biodegradation experiments.
Effects on human health of some toxic cyanobacteria (blue‐green algae) in reservoirs, lakes, and rivers
Authors: Falconer Ian R. 
Published: October 2006

AbstractThe public water supply has been implicated in gastrointestinal disorders in the United States, East Africa, and Australia, associated with the lysis of heavy blooms of cyanobacteria. The causative organisms include Microcystis, Anabaena, Aphanizomenon, and Oscillatoria. Using epidemiological techniques, we have shown significant increase in liver enzymes in blood, particularly γ‐glutamyl transpeptidase, during a toxic bloom in the reservoir of a city. Therefore, public health awareness of the risks, and consequent action to control water blooms and remove harmful compounds from drinking water supplies, is required.
Use of protozoan communities to assess the ecotoxicological hazard of contaminated sediments
Authors: Henebry Michael S. , Ross Philippe E. 
Published: October 2006

AbstractProtozoan communities developed on artificial substrates were used in a series of in situ and laboratory tests to evaluate the toxic potential of harbor sediments contaminated with polychlorinated biphenyl (PCB). Colonization dynamics in polluted and clean harbors were compared. Laboratory tests were community bioassays using standard techniques to produce sediment elutriate. Results of the in situ colonization and the community tests measuring structural changes (e.g., “decolonization”) were similar. In general, sediments from the contaminated harbor caused significant (p ⩽ 0.05) reductions in the number of taxa, in total protozoan abundance, and in phototroph abundance; however, the abundance of heterotrophic species increased in some in situ tests. Process‐level parameters (e.g., respiration; island‐epicenter colonization rates) were more sensitive than measurements of community structure. Phototrophs were more sensitive to sediment elutriate than were other trophic types. The information provided by this series of protozoan community tests is more complex than that provided by single‐species bioassays. Although community tests may provide more information on the effects of sediment contamination on actual ecosystems than tests based on single species, they require careful interpretation to avoid misleading conclusions.
Microbiology of potable water in Canada: An overview of the health and welfare Canada program
Authors: Tobin Richard S. 
Published: October 2006

AbstractResponsibility for drinking water quality in Canada is primarily a provincial obligation, but the Department of National Health and Welfare (NHW) plays an important role in the establishment of national guidelines, conducting research on problems of national concern, and providing advice on point‐of‐use devices. The microbiological quality of drinking water is regarded as one of the most important parameters in view of the low but continuing reports of waterborne disease. During the period from 1974 to 1982, there were 42 reported outbreaks involving 1789 persons. The known causative agents were bacteria, Giardia, and viruses.The microbiology program of NHW includes development of the microbiological parameters in the Guidelines for Canadian Drinking Water Quality, collecting and disseminating the data on waterborne disease in Canada, sponsoring and collaborating in research studies on the microbiological hazards in drinking water, participating in the investigation of local and regional water problems, testing and evaluation of point‐of‐use water treatment devices, and providing educational material for the public and the media. Each of these aspects is described in this paper. Particular emphasis is placed on the waterborne illness in the last decade and some of the results of the studies on Giardia removal or inactivation in potable water.
Bacteriological aspects of a mountain watershed
Authors: Adams J. C. , Skinner Q. D. 
Published: October 2006

AbstractNumbers of fecal coliforms and fecal streptococci increased during the winter in a stream near a ski area. These numbers returned to background levels within a month after the ski area closed for the year. As the pollution events continued with time, the day of the week on which maximal numbers were obtained changed. Maximum numbers of these bacteria were seen in the afternoons when pollution was occurring. Minimum numbers were found in the morning.Fecal coliforms and fecal streptococci were enumerated in a stream above and below the ski area for three summers. Statistically significant differences in the numbers of these organisms occurred between the months studied, depending upon whether the statistics were run upon numbers per 100 mL or upon numbers passing a point per second.
Utilization and water quality management of lake kinneret, Israel
Authors: Gophen M. 
Published: October 2006

AbstractKinneret, the only natural freshwater lake in Israel, is used as the major source for drinking water and is also utilized for commercial fishing, recreation, and tourism. Recreational pressure was averaged as 190 IKD [Individuals/km (53 km shoreline)/day] during May–September. Total population in the drainage basin (2730 km2) is approximated as 255 × 103. Before 1980, most of the domestic sewage (18000 m3/day) and fish‐pond wastes drained into the lake. The major sources of intestinal and pathogenic bacteria found in lake water were untreated domestic sewage, cows in pasture lands through water runoff, and directly from the recreational population. Partial implementation of a master plan for sewage removal has led to the diversion of about 60% of the sewage into reservoirs constructed in the drainage basin for irrigation reuse. Consequently, the presence of intestinal bacteria in Jordan inlet (the major drainage river) declined. Sewage removal systems were also constructed along all the shoreline. Reduction of intestinal bacteria densities in public beach waters was also recorded. On the other hand, nutrients (mostly P) and phytoplankton (density and composition) in the lake slightly deteriorated water quality. The management design is dependent on water quality standards. In the case of a higher quality standard, lake utilization for drinking requires a thorough treatment and water consumption for irrigation is more efficient.
Factors affecting the magnitude of toxicant interactions in microbial bioassays
Authors: Stratton Glenn W. 
Published: October 2006

AbstractA toxicant interaction method was used to study the effects of various bioassay parameters on interaction responses obtained in microbial bioassays. The fungus Pythium ultimum was employed as the test organism, and was exposed to various combinations of the fungicide captan and several organic solvents, using a poisoned agar technique. In all cases the fungicide and solvents interacted synergistically toward culture growth. For most experiments acetone was used as the test solvent. Where pH and temperature were altered, the magnitude of the interaction response between captan and acetone increased dramatically as the pH or temperature was raised from 4.5 to 7.5, or 15 to 30°C, respectively. This corresponded to similar increases in the culture growth rate and decreases in the toxicity of captan. When the medium composition was changed, interaction magnitudes were again greatest in media eliciting the fastest growth rate. These media also yielded the lowest captan toxicity. The largest interaction magnitudes occurred with V8 juice agar, followed by corn meal agar, potato dextrose agar, and malt extract agar. When the solvent used in the interaction experiments was changed, a similar response was obtained, in that the greatest interaction magnitudes occurred in systems eliciting the lowest captan toxicity. The largest magnitudes were measured with acetone, followed by hexane, ethanol, dimethylformamide, methanol, and dimethyl sulfoxide. The significance of these data in toxicant interaction bioassays is discussed.
Assessment of the interaction between microorganism and chemical mixture using resazurin reduction
Authors: Liu D. 
Published: October 2006

AbstractThe interaction between microorganism and chemical mixture was studied using resazurin reduction to delineate the microbial response to toxic substances. Two chemical mixtures, one consisting of two similar chemicals (2,3‐dichlorophenol and pentachlorophenol) and another of two dissimilar compounds (mercuric chloride and 2,3‐dichlorophenol), were tested on three pure bacterial isolates. Various toxicity patterns encompassing synergistic, neutral, and antagonistic effects on test bacteria were observed, demonstrating that the observed toxicity response from a chemical mixture does not always match the summed toxicity responses of the chemicals tested individually. No overall pattern regarding the interaction between microorganism and chemical mixture's toxicity could be drawn, implying that the traditional philosophy of setting water quality standards based on the toxicity assessment of individual chemicals should be readdressed to reflect the complexity of managing toxic substances in the aquatic environment.
Heptapeptide toxins contained in natural samples of Microcystis species
Authors: Watanabe Mariyo F. , Harada Kenichi , Matsuura Kenji , Oishi Shinshi , Watanabe Yasunori , Suzuki Makoto 
Published: October 2006

AbstractToxins contained in Microcystis species were examined for natural samples of water bloom collected from several lakes in Japan. The toxins were identified as microcystins (cyanoginosins)‐LR,‐YR, and ‐RR. The amounts of the three toxins were estimated after adsorption to a C18 cartridge, eluted with methanol, and subjected to high performance liquid chromatography using an octa decylsilanized column. Microcystins‐RR and ‐LR were the main components of the toxins contained in natural samples of Microcystis bloom, while YR was not detected in more than half of the samples analyzed. Six samples were also examined in relation to LD50 values and species composition of Microcystis. The highest total amount of the three toxins was obtained for the sample with the lowest LD50 value and composed mostly of cells of M. aeruginosa. The relation between LD50 values and total contents of the three toxins was well fitted to the formula Y = 1100 × X−1.079, where Y is the LD50 value and X is the total amount of the three toxins.