Submitted by Mendes Eduardo (dasilva@ufba.br) on 2012-03-21T22:53:47Z No. of bitstreams: 1 CohindePinho_DISSERTAÇÃO.pdf: 323932 bytes, checksum: 963d9c845dbfff3273be48ebe3b2c251 (MD5) / Made available in DSpace on 2012-03-21T22:53:47Z (GMT). No. of bitstreams: 1 CohindePinho_DISSERTAÇÃO.pdf: 323932 bytes, checksum: 963d9c845dbfff3273be48ebe3b2c251 (MD5) / Capes, Millennium Inorganic Chemicals / The current study investigates the suitability of a tropical cladoceran species, Macrothrix elegans Sars (1901) for toxicity testing in ecotoxicological tests at 250C involving two reference substances, cadmium chloride (CdCl2) both in natural and artificial media, and potassium chloride (KCl) in natural medium. The work provides a comparison among other cladoceran species from tropical and temperate environments, and discusses the potential of M. elegans as a bioindicator of stress in tropical waters. An experiment on the animal’s life-span has been included to assess its reproductive potential. On average, at 250C, M. elegans lives 38.2 ± 4.4 days and each female produces 211.8±30.4 neonates. The criterion of toxicity adopted in the bioassays was mortality/immobility using neonates up to 24-h old. The CdCl2 48-h EC50 mean values and their confidence intervals were 0.035 mg.l-1 [0.020-0.050 mg.l-1] in natural medium, and 0.018 mg.l-1 [0.012-0.024 mg.l-1] in the artificial medium. The KCl 48-h EC50 mean value (natural medium only) was 749.08 mg.l-1 [625.32-872.76 mg.l-1]. The work demonstrates the great potential of M. elegans as a test organism in ecotoxicological tests involving these substances in tropical freshwater ecosystems. / Salvador, Bahia

Submitted by Mendes Eduardo (dasilva@ufba.br) on 2012-03-21T00:26:13Z No. of bitstreams: 1 Dissertacao Cristiano.pdf: 656578 bytes, checksum: db814e7920e2705e9f75a1087e7d994b (MD5) / Made available in DSpace on 2012-03-21T00:26:13Z (GMT). No. of bitstreams: 1 Dissertacao Cristiano.pdf: 656578 bytes, checksum: db814e7920e2705e9f75a1087e7d994b (MD5) / Capes e Millennium Inorganics Chemicals / Buscou-se avaliar o potencial tóxico da redução do pH sobre o peixe Poecilia reticulata,através de ensaios de ecotoxicidade agudos, bem como avaliar como um aumento no pH da água da lagoa pode influenciar na sua toxicidade. Amostras de água da Lagoa de Dunas foram coletadas e testadas com os seguintes tratamentos: água in natura (pH ± 3,0) e amostras com pH alterados para 3,5, 3,8, 4,0, 4,3, 4,6, 5,0, 5,5, 6,0 e 6,5. Foram usadas ainda amostras da água de cultivo dos peixes, cujos valores de pH foram reduzidos para o mesmo da Lagoa de Dunas. Os resultados médios e respectivos intervalos de confiança do 96 h-LT50 da Lagoa de Dunas e da água de cultivo com pH reduzido foram 1,37 (1,18-1,56)h, e 1,04 (0,73-1,34) h, respectivamente, sem diferença estatística significativa (p ≥ 0,05).Para as amostras da Lagoa de Dunas com valores de pH elevados houve uma redução significativa da toxicidade, não sendo detectada toxicidade a partir do pH 6,0. Estes resultados demonstram que, nestas condições, o pH é o fator limitante para P. reticulata. / Salvador, Bahia