Avaliação ecotoxicológica da qualidade da água e do sedimento no Córrego Tripuí, Ouro Preto MG

Abstract

Stream Tripui located in Ouro Preto, important in the history of the region due to its use during the colonial period for gold mining, is in a process of degradation due to high population growth and industrial exploitation. In this context, this work aimed to reassess the quality of water and sediment of Stream Tripui, from an ecotoxicological point of view,complementing a study by Mendes (2012), which showed through analyses of physical and chemical parameters, indication of water quality degradation in this stream. Two samplings were carried out in four sites along the stream in June 2014, taking into consideration the useand occupation of the basin. Acute and chronic toxicity assays were conducted with water and sediment samples in laboratory, using Ceriodaphnia silvestrii, Daphnia similis and Chironomus xanthus as test-organisms. Among the results, there was acute toxicity effect ofwater samples from two sites of the stream, collected on weekends when we suspect there is waste release into the stream. With regard to sediment samples, none of the points presented acute toxicity effect, probably due to sediment grain size, mainly sandy. The toxicity effectsobserved may be related to the exploitation of topaz, and metallurgical activities near the sampling points. Thus, actions that influence, directly or not, water and sediment quality show the need of constant monitoring as a way to contribute to the conservation of aquatic ecosystems.