Antifouling paint residues in areas impacted by maritime activities along 6000 km of Brazilian coastline

Contamination by antifouling paint residues (TBT, DBT, MBT, diuron, Irgarol, chlorothalonil, dichlofluanid, DCOIT, and antifouling paint particles (APPs)) was assessed in 113 sediments from 10 regions under the influence of maritime activities (boats/shipyard, traffic zones, marina, and port) along the Brazilian coast. The relatively low levels of butyltins (BTs) in sediments associated with commercial ports (mean of 25 ng Sn g-1), in addition to butyltin degradation indexes pointing to old TBT inputs, confirmed the effectiveness of the IMO Antifouling Systems Convention. However, hotspots of TBT were observed at boat/shipyards (mean BTs of 349.9 ng Sn g-1) and marinas (mean BTs of 118.5 ng Sn g-1) probably due to the presence of APPs. DCOIT, followed by diuron, were the most frequently detected booster biocides (BB), reflecting their current use in antifouling paints. Moreover, APPs emerged as a relevant source of contamination due to high associated concentrations of antifouling biocides (i.e., DCOIT - 43,139 ng g-1; TBT - 311,474 ng Sn g-1). Approximately 75 % of the assessed sites presented concentrations of of TBT and/or BB above safe values that potentially trigger effects on organisms. In summary, contamination by antifouling paint residues was widespread along the Brazilian coastal areas under the influence of maritime activities. Thus, environmental and governmental agencies must act and seek regulatory and protective measures to reduce potential risks to aquatic organisms.