Analysis of the concentration of heavy metals in the polychaete using the TXRF technique on sandy beaches of the coast of São Paulo

Full text: The sediment tends to embody and accumulate contaminants poured in the water, in which become available for associated organisms. In this regard, benthic invertebrates such as polychaetes, which often use the sediment to obtain food or to construct protective tubes, are susceptible to the contamination by elements present in this environment. Thus, the present study examined the concentration of heavy metals in the species of polychaete Dispio remanei Friedrich, 1956 found at the beaches of Itararé (São Vicente) and Boracéia (Bertioga) and Orbinia cf. johnsoni Moore, 1909 in Araçá bay and Guaecá beach, both located in São Sebastião. The Araçá and Itararé are located very close to port areas, characterized by high urbanization and industrialization, thus existing possibilities of coastal marine environment being contaminated by heavy metals, that can have negative impacts on the biological, social and economic aspects. During periods of low tide, on each site, was delimited a quadrat area of 100 m², in which three points were randomly selected to obtain individuals D. remanei and O. cf. johnsoni. The material collected was analyzed by using the X-Ray Fluorescence by Total Reflection (TXRF) technique; it is possible to perform the correlation between essential and toxic elements in the body, through the issue of spectrum with energies characteristics of each metal. From procurement of different metal concentrations, comparisons of the mean concentrations between the beaches were conducted. Significant differences were identified for concentrations of Zinc with a higher concentration of the beach Boraceia regarding to the Itararé beach. This result was different than expected, because the beach Boraceia lies far from the places where this metal is used. For species O. cf. johnsoni, we identified a significant difference to the Fe element in the Bay of Araçá, which had a higher concentration than Guaecá Beach. This result was expected, since the Bay of Araça is a receiving area of effluent contents, and it is also very close to the port of São Sebastião, as well as to the industries of the region. Both beaches showed significant differences for the element Potassium. (author)