Legacy and emerging antifouling biocide residues in a tropical estuarine system (Espirito Santo state, SE, Brazil).

The contamination by antifouling biocide residues (booster biocides - diuron, Irgarol, chlorothalonil, dichlofluanid and DCOIT; butyltin compounds-BTs (TBT, DBT and MBT); and antifouling paint particles-APPs) was appraised in sediments of Vitoria Estuarine System (VES). Even at its historical lower (ΣBTs ≤113 ng Sn g dry wt), the current environmental levels of BTs in areas with a predominance of boatyards still pose a risk to the local biota and human population. DCOIT, among booster biocides, was the most frequently detected, especially in boatyards (≤40 ng g dry wt) and Vitoria Port (64 ng g dry wt), while APPs were also detected mainly in sediments of boatyards (≤5,969 μg g dry wt). Since levels of diuron and DCOIT in APPs were as high as 1,670,000 and 899,000 ng g dry wt, respectively, they are acting as secondary sources of these antifouling biocides. Therefore, VES is threatened by antifouling biocide residues due to the multiple diffuse sources of contamination, showing the need for more efforts on public policies (including temporal trend monitoring studies).