Avaliação ecotoxicológica dos metais-traço cobre e zinco, isolados e em mistura, para Daphnia similis e Ceriodaphnia silvestrii

• Autor(a) principal: Nobre, Fernanda Silva de Melo
• Data de Publicação: 2019
• Tipo de documento: Trabalho de conclusão de curso
• Idioma: por
• Título da fonte: Repositório Institucional da UFS
• Texto Completo: http://ri.ufs.br/jspui/handle/riufs/12125
• topic: Engenharia ambiental; Ensino de engenharia ambiental; Testes de toxicidade; Zooplâncton; Bioindicadores; Bioindicadores; Sinergismo; Antagonismo; Metais-traço; Toxicity tests; Zooplankton; Bioindicator; Synergism; Antagonism; CIENCIAS EXATAS E DA TERRA::QUIMICA::QUIMICA ANALITICA::ANALISE DE TRACOS E QUIMICA AMBIENTAL

The anthropogenic activities have caused the discard of countless synthetic and natural chemicals, and the aquatic ecosystems are the most susceptible to the exposure to such toxic agents. The high concentration of trace metals in the aquatic environment presents itself as one of the most serious forms of chemical contamination, because they are non-biodegradable elements. In this context, the main objective of this paper was to assess the acute ecotoxicological effects of the trace metals copper and zinc, individually and in mixture, to Daphnia similis and Ceriodaphnia silvestrii, and compare these effects with those predicted by the models of concentration addition and independent action. The results showed that the median effective concentration of zinc for both test organisms were lower than the maximum limit (180 μg.L-1 ) set by law, CONAMA n0 357/2005, to water bodies of class 2, when individually evaluated, showing that the set value may not be suitable for the maintenance of aquatic biota. Just for Ceriodaphnia silvestrii the observed values were lower than the limit for dissolved copper (9 μg.L-1 ) established by law, showing that the value set for the maintenance of aquatic biota may not be suitable, taking into account the isolated effect. The model of action that best describes the effect of the mixture upon the test organisms was the independent action, and the toxicity occurs at dose level, in other words, occurring antagonism at lower doses and synergism on high doses.