Spatial distribution and historical input of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in sediments from a subtropical estuary (Guaratuba Bay, SW Atlantic)

This study evaluated the occurrence and distribution of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in 22 surface sediment samples and one core collected in Guaratuba Bay, a large and well-preserved estuary in Southern Atlantic, Brazil. The concentration of PCBs in the superficial sediment samples ranged from <LQ (below the limit of quantification) to 5.62 ng g−1, while the concentration of OCPs ranged from <LQ to 0.74 ng g−1. The spatial distribution of the organochlorine compounds (OCs) suggested that the sources of these contaminants are located outside the bay and are related to human activities on the margins of the two main rivers that discharge in the region. The OCs in the sediment core ranged from <LQ to 0.52 ng g−1 and from <LQ to 1.52 ng g−1 for PCBs and OCPs, respectively. Despite their usage worldwide, the low concentrations of OCs in Guaratuba Bay suggest low input levels, which may represent the background levels for this region.