BaselinePolychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in sediments from an urban- and industrial-impacted subtropical estuary (Babitonga Bay, Brazil)

•Presence of DDT and PCB was recorded in superficial sediments in Babitonga Bay.•Concentrations of DDT exceeded the threshold levels defined by sediment quality guidelines.•High proportion of p,p′-DDT near Sao Francisco harbour suggests a recent input into the aquatic environment.

Babitonga Bay is a large estuary, which has been under pressure from anthropogenic activities coexisting with a natural area of Atlantic rainforest and mangrove systems. The concentration of persistent organic pollutants (POPs), such as polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) was determined to evaluate the contamination status and the determine possible pollution sources in the estuary. The ∑ DDT (sum of DDT, DDE and DDD concentrations) was the predominant OCP group, with concentrations ranging from < DL (below detection limit) to 122 ng g− 1. The exceptionally high concentration of p,p′-DDT (80%) found near São Francisco harbour exceeded SQG limits indicating highly toxic conditions in the area that may be attributed to a recent contamination from some local input. In contrast, other sites in the estuary presented higher concentration of the metabolite p,p′-DDE (34%). The results suggest strongly anthropogenic impact in specific sites of this estuary, which need further investigation.