Antifouling booster biocides diuron and irgarol at Brazilian ports

Biofouling, the natural buildup of organisms on submerged surfaces like ship hulls, is usually controlled using antifouling paints containing biocides such as diuron and irgarol, which are widely detected in marine environments. While these paints help reduce maintenance costs and ecological risks like invasive species, their use in port areas can still contribute to environmental pollution and impact coastal ecosystems. In this study, the presence of diuron and irgarol was investigated in water samples collected from the port complex of São Luís and the estuarine systems of Santos and São Vicente in Brazil. A method employing solid phase extraction (SPE) in combination with high performance liquid chromatography equipped with a diode array detector (HPLC-DAD) was validated and applied for the determination of the biocides in surface water. The method demonstrated satisfactory recovery ranging from 72 to 115 % and relative standard deviations below 10 %, with adequate quantification limit of 0.07 ng mL^-1 and 0.50 ng mL^-1 for diuron and irgarol, respectively. Concentrations ranged from 0.30 to 7.39 μgL^-1 for diuron and 1.98 to 5.70 μg L^-1 for irgarol in the studied area, reflecting their current widespread use as primary antifouling agents. Higher concentrations were detected at sites near docking berths, with particularly elevated levels of diuron in anchorage zones. An ecotoxicological risk assessment using the species sensitivity distribution (SSD) approach was performed, indicating that the observed water concentrations of biocides may adversely affect several sensitive species and disrupt key ecological functions in the region, with potential impacts on fisheries and livelihoods.