Determination of radionuclides, trace elements and rare earths in sediment cores of the coast of São Paulo State. Evaluation of the base line and contaminated areas

Abstract

The effects of anthropogenic activities that deliver chemical elements to the marine environment have been increasing in the last years. The main studies concerning this goal aimed to clarify the fate of these elements in the environment, the transfer process and the biologic effects to biota. Generally, heavy metals are among the elements more studied. Nevertheless, few environmental studies concerning alteration in the concentration of trace elements such as rare earth elements and radionuclides are found. The objetive of this study is (1) to determine the concentration of major elements, trace elements, rare earth elements and natural radionuclides in core sediment samples from Santos Bay in São Paulo State; (2) To develop and to implement methodologies for determination of natural radionuclides concentration; (3) To establish values that can be used as background for the region and for quality classification of the sediments (with Cetesb cooperation; (4) To evaluate nowadays and past quality of the sediments and to evaluate the anthropogenic contribution for contamination due to the industrial activities. Methodologies: Instrumental neutron activation analysis (INAA). INAA is a non destrutive, multielemental method that allows the analysis of As, Ba, Br, Cs, Co, Cr, Cu, Eu, Fe, Hf, K, La, Lu, Na, Nd, Rb, Sb, Sc, Se, Sm, Ta, Tb, Yb Zn and Zr in the same sample. This thecnique is based on a nuclear reaction between a nucleos and a neutron. (AU)