Análise das concentrações de metais pesados na água e sedimento do Rio Sergipe (SE)

Abstract

The present work presents the evaluation of Sergipe River water quality that cuts all the Sergipe State. Water and sediment samples were collected at four points along the river, from proximal source area (countryside area) to proximal mouth river (urban area). The collection points are localized at São Miguel do Aleixo, Santa Rosa de Lima, Aracaju cities and on the Laranjeiras and Maruim cities border. The realized analyses aimed to obtain the heavy metals concentrations as cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb) and nickel (Ni) in water and copper (Cu), manganese (Mn) and zinc (Zn) in the sediment. The pH, chlorides, total hardness, apparent colour physical-chemical parameters were also analysed in the water. The values of analyses were compared with the individual acceptance limits established to the Health Ministry for each parameter of water and sediment quality. The water pH (between 7 and 8.5) and apparent colour (between 3 and 23) are within permitted standard. The hardness and chlorides in the water exceed the maximum value allowed in all collection points and the water is classified as brackish. The variations obtained in the heavy metals values to the river water indicate contamination at the collected points, emphasizing the P4 point, where the cadmium (0,03 mg / L), lead (0,51 mg / L) and nickel (0.43 mg / L) values are quite high compared to the standard allowed by CONAMA (0.001 mg Cd / L, 0.01 mg Pb / L and 0.025 mg Ni / L). The heavy metals concentrations obtained to the river sediment indicate that there are no contaminations at the collected points. This work is a contribution to the more effective monitoring of water and sediment contamination levels by heavy metals in the Sergipe River. The obtained data can be used to control and improve the local and regional environment management.