Environmental assessment of dissolved copper concentration in the Grajaú River, Maranhão

The assessment of surface water with regard to heavy metal levels is a subject of great interest, both for its environmental and social relevance. The present study aims to analyse water samples from the Grajaú River, located in the state of Maranhão, with regard to copper levels, in order to assess possible impacts on the environment. To this end, six water samples were collected from the Grajaú River at different collection points, and the metal was quantified using graphite furnace atomic absorption spectrometry. The results found were 0.01 to 0.08 mg L-1 of copper in these samples. The copper concentrations in water samples exceeded the maximum limits established for class 3 river water, according to Resolution 357/2005 of the National Environment Council (CONAMA). The highest concentrations were found in areas of disorderly growth of residences and domestic effluents.