HEAVY METAL LEVELS IN BIOTA FROM TODOS OS SANTOS BAY, BAHIA STATE, BRAZIL

Gilberto M. Amado-Filho1*, Carlos E. Rezende2, Leonardo T. Salgado1, Mauro F. Rebelo, José D. Correa-Junior, e Wolfgang C. Pfeiffer3 1. Programa Zona Costeira, Instituto de Pesquisas Jardim Botânico do Rio de Janeiro, Rua Pacheco Leão 915, 22460-030 Rio de Janeiro, RJ. E.mail: gfilho@jbrj.gov.br 2. Laboratório de Ciências Ambientais, CBB/UENF.3. Laboratório de Radioisótopos, Instituto de Biofísica, UFRJ.

The area of Todos os Santos Bay (927 Km2) presented a high industrial development along the last 20 years, including petrochemical and metallurgical activities. Although their fisheries and tourist importance, no data are available about heavy metals concentration in both abiotic and biotic compartments. In a first approach, benthic organisms (seaweeds, seagrasses, mollusks and crustaceans) were collected during 1999 in 4 sites of the Bay and prepared for metal analysis. Composite sample of each species were digested with a concentrated HNO3/HCl solution moisture in triplicates, and re-suspended with HCl 0.1N. Al, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn were determined by flame atomic absorption spectrophotometry (VARIAN AA-1475). Among the metals analyzed (results expressed as µg.g-1 dry weight), elevate levels of Cd and Cu were found in the seaweed Padina gymnospora (Cd = 4.26 + 0.39 µg.g-1, Cu = 32.4 + 1.26 µg.g-1), in the seagrass Halodule wrightii (roots Cd = 1.87 + 0.52 µg.g-1, Cu = 75.9 + 4.92 µg.g-1; leaves, Cd = 2.32 + 0.31 µg.g-1, Cu = 71.7 + 5.41 µg.g-1) and in the oyster Crassostrea rhizophorae (Cd = 6.78 + 0.8 µg.g-1, Cu = 526 + 153 µg.g-1). These data are significantly higher (p < 0.01) than that found in the same species collected in other polluted Brazilian coastal waters and in the case of the oyster, the levels of Cu are higher than the limit for human consumption. The concentration of other analyzed elements in macrophytes, mollusks and crustaceans are similar to that of non-contaminated areas.

Financial support: CNPq, PRONEX/MCT, FENORTE, FAPERJ.