CADMIUM AND ZINC SOURCE ASSESSMENT IN THE SEPETIBA BAY AND BASIN REGION

Industrial and weathering inputs of Cd and Zn to the Sepetiba Bay and basin were assessed, based on production parameters obtained from loca l environment and industry authorities, and literature data. The resul ts are compared with similar evaluations from other coastal regions an d field data obtained in measuring Zn and Cd transport by rivers, dire ct run-off and atmospheric deposition in the region. Cadmium and zinc inputs to the bay increased by three orders of magnitude relative to p re-industrial fluxes and presently reach up to 1.6 and 180 tonnes per year for Cd and Zn, respectively, which represents a large input-to-ar ea ratio, and explains the high concentration of these metals previous ly reported in the estuarine biota and sediments of Sepetiba Bay. Indu strial activities, mainly metallurgical and chemical, comprise 94% and 84% of the total Cd and Zn inputs to the Bay. This figure identifies the point sources as being responsible for the environmental contamina tion and for regional poisoning risks.