Utilização da comunidade de macroinvertebrados bentônicos na avaliação de impactos ambientais em arroios da bacia hidrográfica do Rio dos Sinos, Rio Grande do Sul, Brasil

Abstract

Aquatic ecosystems suffer great pressures from human populations. Agriculture, industrialization and uncontrolled growth are among the today´s main causes of destruction of the water resources, being the monitoring needed for future projects of rehabilitation and restoration. The main objective of this dissertation was to evaluate the water quality of nine streams of the Sinos River basin (Rio Grande do Sul State, Brazil), with three sampling sites per stream, using the community of benthic macroinvertebrates as biological indicators, using biotic indices. The streams were previously studied by Monalisa Project which, in 2006, examined different types of environmental impacts. The macroinvertebrates were collected by sweeps in the sediment and the water column using a "frame dip-net," trying to achieve a minimum of 100 individuals. In the macroinvertebrates collection sites were recorded physical and chemical variables on water. The overall quality of the basin’s waters ranged from “Excellent” to “Poor”, redu