Variability of labile metals in estuarine sediments in areas under the influence of antifouling paints, southern Brazil

Antifouling paint residues may contribute to high concentrations of metals in sediments. This study aims at assessing seasonal variations of labile metals (Cu, Zn, Pb, Cr and Ni) in surficial sediments (<63 mu m) of port, marina and shipyard locations in southern Brazil under the influence of antifouling paints for vessels. The highest concentrations of Cu and Zn in the sediment of shipyard areas were consistent with the composition of the most used antifouling paints, which were analyzed for the first time. The extended El Nino effect on the region caused a decrease in concentrations of labile metals in the sediment. A high correlation between Cu and Zn in the sediment could indicate that they may have the same source, antifouling paints. Levels of Pb were correlated to concentrations of Cu and Zn, and these, to Cr and Ni to a lesser extent. Data were compared with concentrations of trace metals in marine sediment established by the National Oceanic and Atmospheric Administration (NOAA) Screening Quick Reference Tables which indicate the toxicity levels of the sediment. Labile Cu, Zn and Pb levels at shipyard and marine areas exceeded the NOAA values, thus, showing that these areas need attention regarding the waste input of antifouling paints, marine diesel oil and lubricants.