Procedimento de fracionamento e modelagem geoestatística para avaliação dos teores, disponibilidade e mobilidade de cobre em sedimentos da Baia de Sepetiba-RJ

Abstract

This work aimed to'assess copper contamination and mobility in sediments from Sepetiba bay. Rio de Janeiro, where an industrial park composed by about 400 plants, basically metallurgical, is responsible for the input of large amounts of metals, releasing their effluents either directly into the bay or through the local rivers. Copper total concentration, the acid-volatile sulfides (AVS) and the concentration of simultaneously extracted metals (ESEM) were determined in 65 sediment samples collected throughout Sepetiba bay. A geostatistical approach, the attenuation of concentrations model, which aims to estimate the metal mobility was employed. The results obtained showed that Cu presented higher concentrations in the northeastern area, near the entrance of the rivers into the bay. The comparison between copper concentrations with the Canandian Sediment Quality Guidelines (TEL and PEL) showed that Cu levels were below PEL, suggesting low probability of toxicological effects to the aquatic organisms. The ratio FSEM/AVS was below I in northeastern region indicating that in this area Cu is trapped in the sediment as sulfide. The geostatistical approach presented the highest attenuation values for Cu in the northeastern region of Sepetiba bay. indicating low mobility of this metal in this region of the bay, suggesting low availability which is in good agreement with the ESEM/AVS results.