Gewässer sind Lebensgrundlage, jedoch gleichzeitig Schadstoffsenken für eine Vielzahl von Kontaminanten. Biologische Wirkungstests und das Biomonitoring aquatischer Proben sind daher besonders wichtig, um Umwelt-Gefahrenpotenziale erkennen zu können. Der "Comet Assay" (Einzelzell-Gelelektrophorese) ist ein Indikator von DNA-Strangbrüchen und wurde hier als Test auf gentoxische Wirkungen erprobt und angewandt. Mit bekannten, gentoxischen Substanzen wurden Nachweisgrenzen und Dosis-Wirkungs-Beziehungen für die Zelllinien RTG-2 und RTL-W1 (aus der Regenbogenforelle, Oncorhynchus mykiss) in vitro ermittelt und methodische Parameter an die Zellen angepasst. Der Test reagierte sehr sensitiv auf 4-Nitrochinolin-1-oxid. Die Substanz war daher geeignet, um in weiteren Versuchen als Positivkontrolle zu dienen. Zur Bewertung der Messdaten wurde ein geeignetes statistisches Verfahren gefunden, das auch historische Kontrollen mit einbezog. Der zeitliche Verlauf der DNA-Schädigung des Testsystems mit RTG-2-Zellen wurde ermittelt, und durch Inhibition der DNA-Reparatur mit Aphidicolin wurden Zusammenhänge zwischen der Entstehung von DNA-Strangbrüchen, der DNA-Reparaturkapazität sowie der Metabolisierungskapazität untersucht. In einer zweiten Phase wurden unbehandelte Wasserproben aus Rhein, Elbe sowie weitere Oberflächenwasserproben mit dem Comet Assay an RTG-2-Zellen getestet. Bei 15 von 49 Proben zeigten sich gentoxische Effekte. In einer dritten Phase wurden Erythrozyten von freilebenden Döbeln, Leuciscus cephalus, aus der Mosel mit dem Comet Assay untersucht. Die Fische von drei Messstellen zeigten erhöhte Werte von DNA-Schädigungen, gegenüber einer vierten, stromabwärts gelegenen Messstation. Korrelationen mit den Ergebnissen zusätzlicher Biomarker ergaben sich nur teilweise. Chemische Analysen von Wasser- oder Gewebeproben ließen keine Rückschlüsse auf verursachende Kontaminanten zu - gerade dies unterstreicht jedoch die Wichtigkeit biologischer Tests bei komplexen Proben. / Bodies of Water are both vital resources and pollutant sinks for a multitude of contaminants. Therefore, biological effect tests and biomonitoring of aquatic samples are of particular importance to detect potential environmental hazards. The "comet assay" (single cell gel electrophoresis) is an indicator for DNA strand breaks and was explored and applied as a genotoxicity test in the present study. Known genotoxic substances were used to determine the detection limits and dose-response relationships for the cell lines RTG-2 and RTL-W1 (from rainbow trout, Oncorhynchus mykiss) in vitro, and to adapt methodological parameters to the cells. The test was very sensitive to 4-Nitroquinoline-1-oxide. This substance was therefore well-suited to serve as positive control in further experiments. In order to evaluate the measurement data, an appropriate statistical procedure was developed, which also took "historical" controls into account. The time course of DNA damage in the test system using RTG-2 cells was determined, and relationships between the origin of DNA strand breaks, DNA repair capacity and the metabolizing capacity of the cells was investigated by means of inhibition of DNA repair with Aphidicoline. In the second stage, native water samples from the rivers Rhine and Elbe and further surface waters were tested with the comet assay, using RTG-2 cells. 15 out of 49 samples showed genotoxic effects. In a third stage, erythrocytes of feral chub, Leuciscus cephalus, from the Moselle river were examined with the comet assay. The fish from three measuring stations showed elevated values of DNA damage compared to fish sampled from a downstream station. There were only partly correlations with the results from additional biomarkers. Chemical analyses of water and tissue samples did not permit conclusions on effect-causing substances.However, this emphasizes the importance of biological tests in dealing with complex environmental samples.

This thesis seeks to uncover women’s concerns about chemicals in the household, and, more specifically, in cleaning products. The research is based on semi-structured interviews with women who are primarily responsible for household cleaning and who consciously avoid conventional cleaning products. From a sociological standpoint, the topic remains unstudied. The women were critical of greenwashing and the institutions responsible for chemical regulation. Further, the women’s chemical-free lifestyle defied conventional definitions of activism. Sociological theories of risk are used to help understand women’s avoidance of chemicals. It was found that tenets of the precautionary principle were reflected in their reasoning for avoiding chemicals. Recent biomonitoring and body burden studies have influenced women’s knowledge of chemical risk and their decision to avoid them. The thesis demonstrates that risk-management, in this context, has become an individualized pursuit reflective of the neo-liberal ideology informing chemical regulation. / Canadian Institutes of Health Research

Made available in DSpace on 2017-07-10T18:13:14Z (GMT). No. of bitstreams: 1 Denise N de Bastos.pdf: 584150 bytes, checksum: 5ec6369c1a7266f038b37ea1a2b8ccdd (MD5) Previous issue date: 2013-06-26 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / The objective of this study was to avaluate the toxicity to Daphnia magna cultivated on a large scale and post-larvae of jundia (Rhamdia quelen) to Glyphosate herbicide and the reference substances. Were used daphnia with age between 2 and 26 hours of life, from large scale cultured arrays. There were performed six sensitivity assays that were composed of seven treatments and three replica, at concentrations of 0; 0.1; 0.3; 0.5; 0.7; 0.9 and 1.2 mg.L-1 of potassium dichromate, with 24 hours duration. The acute toxicity assays, with copper sulfate at concentrations of 0; 0.01; 0.025; 0.05; 0.075 and 0.10 mg.L-1, and to the glyphosate concentrations of 0; 11; 21; 31; 41 and 51 µg.L-1, with three and two replica respectively, and 48 hours duration. However the post-larvae of jundia were exposed to concentrations of 0; 0.5; 1.0; 1.5; 2.0 and 2.5 mg.L-1 of glyphosate, per 96 hours. Each replica was composed of a bottle with 10 individuals. The chronic toxicity test, the daphnia were exposed to concentrations of 0, 2, 4, 6, 8 and 10 µg.L-1 of glyphosate, with 10 replica, being a daphnia per replica, evaluating the survival and fecundity in 21 days. For acute toxicity assays, was calculated mortality using the Median Effective Concentration (EC50) in each test. The mean EC50 for D. magna with potassium dichromate was 0.57 mg.L-1. The value of acute toxicity for copper sulphate was reached at a concentration of 0.034 mg.L-1. And for the glyphosate the EC50 of 32 µg.L-1 is toxic for the species. The chronic assay showed high rate of mortality, possibly the result of unfavourable conditions for the large scale cultivation of arrays, hurt his endurance. For the R. quelen the EC50 was achieved at 0.9 mg. L-1. The results showed that organisms of the species D. magna cultivated on a large scale can be used in acute toxicity tests, but not in chronic toxicity testing, for the assessment of water quality. / O objetivo deste trabalho foi avaliar a toxicidade de Daphnia magna cultivada em larga escala e pós-larvas do jundiá (Rhamdia quelen) ao herbicida Glifosato e a substâncias de referência. Foram utilizadas dáfnias com idade de 2 a 26 horas de vida, provenientes de matrizes cultivadas em larga escala. Foram realizados seis ensaios de sensibilidade que foram compostos por sete tratamentos e três réplicas, nas concentrações de 0; 0,1; 0,3; 0,5; 0,7; 0,9 e 1,2 mg.L-1 de dicromato de potássio, com duração de 24 horas. E os testes de toxicidade aguda, com sulfato de cobre nas concentrações de 0; 0,01; 0,025; 0,05; 0,075 e 0,10 mg.L-1, e para o glifosato as concentrações de 0; 11; 21; 31; 41 e 51 µg.L-1, com três e duas réplicas respectivamente, e duração de 48 horas. Já as pós-larvas de jundiá foram expostas às concentrações de 0; 0,5; 1,0; 1,5; 2,0 e 2,5 mg.L-1 de glifosato, por 96 horas. Cada réplica era composta de um frasco com 10 indivíduos. No teste de toxicidade crônica, as dáfnias foram expostas as concentrações de 0, 2, 4, 6, 8 e 10 µg.L-1 de glifosato, com 10 réplicas, sendo uma dáfnia por réplica, avaliando a sobrevivência e fecundidade em 21 dias. Para os experimentos de toxicidade aguda foi calculada mortalidade através da Concentração Efetiva Mediana (CE50) em cada teste. A média da CE50 para a D. magna com dicromato de potássio foi de 0,57 mg.L-1. O valor de toxicidade aguda para o sulfato de cobre foi alcançado na concentração de 0,034 mg.L-1. Já para o glifosato a CE50 de 32 µg.L-1 é toxica para a espécie. No teste crônico, a alta taxa de mortalidade possivelmente é resultado das condições desfavoráveis no cultivo das matrizes em larga escala, o que prejudicou sua resistência. Para o R. quelen a CE50 alcançada foi em 0,9 mg.L-1. Os resultados demostraram que organismos da espécie D. magna cultivadas em larga escala podem ser utilizados em testes de toxicidade aguda, mas não em testes de toxicidade crônica, para a avaliação da qualidade da água.