Kooperativer Bibliotheksverbund

Berlin Brandenburg

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  • 1
    Language: English
    In: Water Quality Research Journal, 5/1998, Vol.33(2), pp.185-212
    Description: Methods for the measurement of the biodegradability of a compound in the environment and in wastewater treatment plants are reviewed with emphasis on methods relevant to Canada. The characteristics of standard and non-standard biodegradability tests are considered. A tiered system for selecting biodegradability tests is proposed. Factors to be considered in the selection procedure are outlined: test duration, applicability to substrates, pass level criterion, carbon source requirements, co-metabolism and inhibition, data quality, and relevance of tests. Biodegradability test data for single chemicals are reviewed. A tiered system of substance evaluation is recommended. The recommended tests were based on ISO standards or their equivalents. There are 45 references.
    Keywords: Monitoring and Analysis of Water and Wastes;
    ISSN: 1201-3080
    E-ISSN: 2408-9443
    Source: CrossRef
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  • 2
    Language: English
    In: Water Quality Research Journal, 08/2001, Vol.36(3), pp.619-630
    Description: We describe the relationship between the estrogen receptor binding and the molecular structure of chemicals using the probabilistic neural network methodology with structural fragment descriptors as input variables and a data set of 1118 compounds. Exploratory models identified two subsets of chemicals for which the predictions were well correlated with the measured values, namely chlorine-containing compounds and carboxylic esters, and for which individual models were developed. Both compound classes are in the classification system for chemicals on the Canadian Domestic Substances List (DSL) and the data cover five orders of magnitude in activity in each of these classes. The results show excellent performance of both models and are highly encouraging in the search for other models for this and other receptor binding data as well as other classes of DSL substances. They also confirm the flexibility, usefulness and applicability of the probabilistic neural networks as modeling methodology to a wide variety of modeling challenges in the environmental and health fields.
    Keywords: Engineering ; Environmental Sciences;
    ISSN: 1201-3080
    E-ISSN: 2408-9443
    Source: CrossRef
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  • 3
    Language: English
    In: Water Quality Research Journal, 05/2004, Vol.39(2), pp.75-82
    Description: Organochlorine concentrations, on a lipid basis, were determined for formalin-preserved sea lamprey larvae, collected between 1960 and 1976 in the Mad River, Lake Huron basin, and compared with previously published data from Michipicoten River, Lake Superior basin. Although the ages of the lamprey specimens between the two lake basins were different, their lipid content, expressed as a percentage of dry body weight, was comparable. Despite the fact that the samples came from areas separated by about 550 km and with different land use (heavily forested area with mining activities but little agriculture for Lake Superior versus poultry farming, agricultural, urban and military uses for Lake Huron), no statistically significant differences were found for most organochlorine residue concentrations ( capital sigma aldrin, capital sigma CB, capital sigma chlordane, capital sigma DDT, capital sigma endosulfan and capital sigma PCB) between the two lake basins. The exception was capital sigma HCH, which was significantly lower in Lake Huron due to the absence of a high-level period observed in 1970 to 1975 in Lake Superior samples. Additionally, no differences were found between the relative concentrations of the various DDT metabolites between the two basins, but significantly higher relative concentrations of higher chlorinated PCBs (hexa to decachloro congeners) were found in Lake Huron samples. This study demonstrates the usefulness of formalin-preserved museum material to conduct retrospective contaminant analyses. However, given that certain amounts of contaminants were also found in the preservative solution, consideration of these levels is important to properly interpret the results.
    Keywords: Scientific Research ; Organochlorine Compounds ; Larvae ; Contaminants ; Water Pollution ; Rivers ; Agriculture ; Pollution Monitoring ; Organochlorine Compounds ; Larvae ; Water Pollution ; Lakes ; Bioaccumulation ; Ddt ; Mining ; Industrial Pollution ; Military ; Urban Areas ; Rivers ; Poultry ; Lakes ; Lamprey ; Pollutants ; Exotic Species ; Water Pollution Effects ; Lipids ; Ddt ; Larvae ; Lake Basins ; Rivers ; Poultry ; Lakes ; Lamprey ; Pollutants ; Exotic Species ; Water Pollution Effects ; Lipids ; Ddt ; Larvae ; Lake Basins ; Petromyzon Marinus ; Canada, Michipicoten R. ; Canada, Ontario, Superior L. ; Canada, Ontario, Huron L. ; Canada, Mad R. ; North America, Superior L. Basin ; Environmental Impact ; Freshwater Pollution ; Effects of Pollution ; Effects of Pollution ; General ; Sea Lamprey;
    ISSN: 1201-3080
    E-ISSN: 2408-9443
    Source: CrossRef
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  • 4
    Language: English
    In: Water Quality Research Journal, 05/2004, Vol.39(2), pp.83-92
    Description: Organochlorine contaminant levels were compared between the native unionid Elliptio complanata and the exotic zebra mussel, Dreissena polymorpha, at four sites along the Rideau River near Ottawa in 1995. Overall, the two taxa exhibited similar bioaccumulation patterns. PCB congeners, treated individually or as classes, showed strong positive and significant correlations between the two taxa. Additionally, the ratios DDD/ capital sigma DDT, DDE/ capital sigma DDT and DDT/ capital sigma DDT were not significantly different between the two taxa. Mean concentrations of capital sigma PCB, capital sigma DDT, and capital sigma chlordane were 65.8, 14.0, 1.2 and 227.9, 10.6, 1.8 ng/g soft tissue dry weight in E. complanata and D. polymorpha, respectively. These three organochlorine groupings accounted for 98.2 and 98.7% of the organochlorine soft tissue dry weight burden in E. complanata and D. polymorpha, respectively. However, while the bioaccumulation patterns were similar in E. complanata and D. polymorhpa, the capital sigma PCB concentration was significantly higher in D. polymorpha. The organochlorine dry weight burden was 2.0 to 5.6 times greater in D. polymorpha compared to that in E. complanata and this was mostly attributable to differences in capital sigma PCB. This difference may be explained in part by the relative lipid content in D. polymorpha being 1.8 times greater on average than in E. complanata. It is concluded that D. polymorpha is a good alternative freshwater biomonitor for E. complanata.
    Keywords: Bioaccumulation ; Lipids ; Pesticides ; Monitoring ; Pcb ; Elliptio Complanata ; Dreissena Polymorpha ; Canada, Ontario, Rideau R. ; Freshwater ; Effects on Organisms;
    ISSN: 1201-3080
    E-ISSN: 2408-9443
    Source: CrossRef
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  • 5
    Language: English
    In: Water Quality Research Journal, 05/2002, Vol.37(2), pp.429-444
    Description: There has been little consistency to date in the method used to express concentrations of organic contaminants in zebra mussels (Dreissena polymorpha), collected from the Great Lakes. Concentrations have been reported on a wet whole (with shells), dry whole, wet soft tissue, dry soft tissue, and lipid weight basis. This study examined residues of organic contaminants in samples of Zebra mussels collected from 24 sites in the lower Great Lakes and St. Lawrence River, to determine if the way in which the residues were normalized could affect the precision of estimated concentrations or the spatial trends observed. Variation in the moisture content of soft tissues was minimal, so normalizing to wet or dry soft tissue weight would yield consistent results. Moisture content of whole mussels was more variable, and relative proportions of soft tissues and shell vary with size, season and location - potentially confounding spatial trends. Lipid content also varies greatly among locations, seasons and years, and lipid-normalized residues were much more variable than residues normalized to whole or soft tissue weight. Furthermore, site-to-site trends based on lipid-normalized data did not always agree with those based on other components of the organism, and thus should not be interpreted in isolation.
    Keywords: Standardization ; Pollution Monitoring ; Bioaccumulation ; Lipids ; Methodology ; Dreissena Polymorpha ; North America, Great Lakes ; Freshwater ; Methods and Instruments ; Effects on Organisms;
    ISSN: 1201-3080
    E-ISSN: 2408-9443
    Source: CrossRef
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  • 6
    Language: English
    In: Water Quality Research Journal, 8/1997, Vol.32(3), pp.637-658
    Description: Various aspects connected to the use of feed forward backpropagation neural networks to build mulitvariate QSARs based on large data sets containing considerable amounts of important information are investigated. Based on such a model and a 419 compound data set, the explicit equation of one of the resulting multivariate QSARs for the computation of toxicity to the fathead minnow, Pimephales promelas is presented as function of measured Microtox, logarithms of molecular weight and octanol/water partition coefficient, and 48 other functional group and discrete descriptors.
    Keywords: Chemical Pollutants ; Neurotoxins ; Toxicity ; Multivariate Analysis ; Pimephales Promelas ; Freshwater ; Effects on Organisms ; Vibrio Fischerei ; Prediction;
    ISSN: 1201-3080
    E-ISSN: 2408-9443
    Source: CrossRef
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  • 7
    Language: English
    In: Water Quality Research Journal, 2/1998, Vol.33(1), pp.153-166
    Description: The connection was investigated between the data preprocessing strategy and kernel choice on the quality of the associated basic probalistic neural network models for the acute toxicity of various chemicals to the fathead minnow ( Pimephales promelas) and to Vibrio fischeri bacteria. The models employ exclusively structural parameters and physicochemical properties as inputs. Results show that the Gaussian kernel is preferable over the reciprocal kernel model. Data preprocessing based on the hyperbolic tangent and the sigmoid logistic transforms provides the best results at the level of the cross validation experiment. Improved models based on cross validation partial models and linear corrections were also investigated. Results show that the improved models with data preprocessing based on the hyperbolic tangent and the finite interval transforms are the best with practically identical quality of predictions.
    Keywords: Pollution Effects ; Toxicity ; Chemical Compounds ; Neurophysiology ; Pimephales Promelas ; Vibrio Fischeri ; Freshwater ; Methods and Instruments ; Effects on Organisms ; Mathematical Models ; Performance Assessment;
    ISSN: 1201-3080
    E-ISSN: 2408-9443
    Source: CrossRef
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  • 8
    Language: English
    In: Water Quality Research Journal, 5/1996, Vol.31(2), pp.411-432
    Description: Zebra mussels were collected from 24 sites in Lake Erie, Lake Ontario and the St. Lawrence River between 1990 and 1992. Composite samples of whole mussels (15 sites) or soft tissues (9 sites) were analyzed for residues of organochlorine pesticides and PCBs to evaluate zebra mussels as biomonitors for organic contaminants. Mussels from most sites contained measurable quantities of most of the analytes. Mean concentrations were (in ng/g, whole mussel dry weight basis) 154 capital sigma PCB, 8.4 capital sigma DDT, 3.5 capital sigma chlordane, 3.4 capital sigma aldrin, 1.4 capital sigma BHC, 1.0 capital sigma endosulfan, 0.80 mirex and 0.40 capital sigma chlorobenzene. Concentrations varied greatly between sites, i.e., from 22 to 497 ng/g for capital sigma PCB and from 0.08 to 11.6 ng/g for capital sigma BHC, an indication that mussels are sensitive to different levels of contamination. Levels of capital sigma PCB and capital sigma endosulfan were highest in mussels from the St. Lawrence River, whereas mirex was highest in those from Lake Ontario. Overall, mussels from Lake Erie were the least contaminated. These observations agree well with the spatial contaminant trends shown by other biomonitoring programs. PCB congener class profiles in zebra mussels are also typical for nearby industrial sources, e.g., mussels below an aluminum casting plant contained 55% di-, tri- and tetrachlorobiphenyls versus 31% in those upstream. We propose the use of zebra mussels as biomonitors of organic contamination in the Great Lakes.
    Keywords: Spatial Distribution ; Monitoring ; Indicator Species ; Pollutants ; Water Pollution ; Bioindicators ; Pcb Compounds ; Water Pollution ; Spatial Distribution ; Organic Pesticides ; Polychlorinated Biphenyls ; Monitoring ; Water Pollution Effects ; Pollutants ; Mussels ; Bioindicators ; Water Pollution ; Dreissena Polymorpha ; North America, Great Lakes ; Effects of Pollution ; Miscellaneous ; Freshwater Pollution ; Dreissena Polymorpha ; Pcb ; Pcb Compounds ; Bioindicators ; Indicator Species ; Monitoring ; Mussels ; Organic Pesticides ; Pesticides (Organochlorine) ; Pollutants ; Polychlorinated Biphenyls ; Spatial Distribution ; Water Pollution Effects ; Zebra Mussels;
    ISSN: 1201-3080
    E-ISSN: 2408-9443
    Source: CrossRef
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