Use of GIS for the evaluation of heavy metal contamination in the Cunha Canal watershed and west of the Guanabara Bay, Rio de Janeiro, RJ

The Cunha Canal watershed, which is located in the municipality of Rio de Janeiro, suffered severe environmental degradation in recent decades due to rapid urban population growth. However, this substantial growth did not result in social development; instead, it exacerbated existing environmental and social problems. This study aimed to evaluate the pollution of the Canal do Cunha and Guanabara Bay, using GIS for mapping based on the result of the heavy metal concentrations obtained by spectrometry (ICP-OES). The analyzed data were monitored at five collection points. Five heavy metals (Cd, Pb, Cu, Ni and Zn) were evaluated. The results showed that the waters of the Cunha Canal watershed and the west side of Guanabara Bay have been altered and degraded. The concentration of heavy metals in the water was lower than the concentration in the sediments. The behaviors of the studied metals differed during the rainy and dry periods.