Resíduos de mineração e metalurgia: efeitos poluidores em sedimentos e em espécie biomonitora - Rio Ribeira de Iguape - SP / Residues of mining and metallurgy: pollutant effect in sediments and biomonitor organism - River Ribeira de Iguape

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

For approximately 40 years, Ribeira de Iguape River received mining wastes (enriched in Cu, Cr, Pb, Ag and Zn) and metallurgical slags (enriched in Cu, Zn, Cr, Fe, Pb and As), produced and discharged by Plumbum S/A, a company located in Adrianópolis (Paraná). In order to verify the contribution of these residues in the river contamination and natural purification the compartments of mining residues, sediments and bioindicator organisms were evaluated. Physical and chemical characterizations were realized in the residues samples; while chemical analyses, grain size evaluation and MEV/EDS were carried out in sediments. Asiatic clam (Corbicula fluminea) was taken as a bioindicator, through chemical analyses of its tissues and shells. The results showed high Pb levels, being classified as Class 1 ? dangerous - by ABNT, norm NBR 10,005, once the limited levels were exceeded by Rocha wastes (32x), Plumbum wastes (41x) and slags (34x). The Plumbum waste is currently the most problematic, as it is made of fine grain, lower pH, higher Pb level detected in the extraction test and is deposited very close to the draining site. The interactions of these residues with the aquatic system was verified through Pb, Zn, Cu detection in the sediments. Pb and Zn levels were, respectively, 135.00 mg/kg and 112.62 mg/kg in the sand banks deposits, and 124.00 mg/kg and 133.00 mg/kg in the estuaries deposits, with prominent metal levels in Iporanga and, secondary, in Crab Island, region of the Small Sea, south of Iguape. MEV/EDS analyses carried out in suspended sediments showed the presence of slags grains, suggesting that still nowadays they are transported and interact with the environment, once they have been detected in tissues and shells samples of Corbicula fluminea. In the tissues of this bioindicator, there were detected average levels of 23.99 ?g/g of Cu, 144.21 ?g/g of Zn, 0.71 ?g/g of Cd, 7.11 ?g/g of Cr and 2.41 ?g/g of Pb; making evident that this last value is strongly high and over the ANVISA reference (2.00 ?g/g) for fish and other consumption products. The results suggest that natural processes of Ribeira de Iguape River are not sufficient for its purification, keeping metalstransport and bioavailability, which can accumulate in the trophic chain, representing a serious environmental problem.

ASSUNTO(S)

bioindicator sedimentos metais pesados sediments wastes heavy metals biomonitores resíduos

ACESSO AO ARTIGO

Documentos Relacionados