The marine mussel Perna perna (Mollusca, Bivalvia, Mytilidae) as an indicator of contamination by heavy metals in the Ubatuba Bay, Sao Paulo, Brazil

Heavy metal levels were determined in marine mussels Perna perna collected from Ubatuba Bay, northern coast of the State of Sao Paulo, Brazil, during the period from January to October 1995. The objective of the present study was to analyze the seasonal concentrations of some metals of toxicological interest (Cd, Cu, Cr, Pb and Zn) in Ubatuba Bay using the bivalve Perna pe rna (Linnaeus, 1758) as a biological monitor. Collections were performed at three month intervals at Itagua beach. In the laboratory, the frozen speci mens were thawed at room temperature, removed from their shells, partially dried on filter paper, weighed and individually submitted to acid digestion with sulfuric acid and hidrogen peroxide. The analyses for the detection o f Cd, Cu, Cr, Pb and Zn were carried out by flame atomic absorption spectro photometer. The results showed higher metal accumulation during July. The v alues detected for Pb and Cr were relatively high in all seasons, especiall y in January and July (vacation periods) in Ubatuba Bay, with the consequen t risk of contamination by mussel ingestion for the local population and fo r tourists from other regions.