Poluiçäo por metais pesados na bacia do rio Sapucaí-Mirim(nordeste do Estado de Säo Paulo, Brasil), pela indústria do couro / Heavy-metal polluition in basin of Sapucaí-Mmirim river (northeast of Säo Paulo State, Brazil), by hide industry

RESUMO

Contamination of the limnic environment is occuring at a fast rate all over the world due to the wide industrial expansion and, at the same time, to the lack of infrastructure for previous treatment of effluents that are dumped into fresh water sources, significantly contributing to the high rates of pollution affecting small and large rivers close to urban centers. The objective of the present study was to analyze the sediment and water of the Sapucaí-Mirim River, an important river in the Northeasten part of the State of Säo Paulo that receives industrial effluents from Franca and Säo Joaquim da Barra, where the major source of pollution is the leather industry which mainly uses Cr for tanning. In the present study we investigated the presence of the metals Cd, Cr, Cu, Pb and Zn at he sites where the Ribeiräo dos Bagres stream empties into the Sä Joaquim stream and the Sapucaí-Mirim River. High metal levels were detected in both regions, with no significant differences between them. The differences detected were loca, with the highest indices being found in the tributaries of the Sapucaí-Mirim River. The metals detected in the water were limited to Cr and Zn, with levels of the order of 0.006 ug/ml to 0.168 ug/ml Cr and 0.002 ug/ml to 0.033 ug/ml Zn. All the metals analyzed were detected in the sediment, with Cr and Zn again being present at highest concentrations. Cr ranged from 17.800ug/g to 242.425 ug/g and Zn ranged from 142.000 ug/g to 1024.000 ug/g. With respect to Cr, the contamination in the region studied was attributed to the leather industry for the manufacturing of shoes