Lagerström, M., Wrange, A.-L., Oliveira, D. R., Granhag, L., Larsson, A., & Ytreberg, E. (2021).

To combat unwanted fouling on immersed hulls, biocidal antifouling coatings are commonly applied to vessels. The Baltic Sea region is a heavily trafficked marine region, by ships and recreational boats alike. The large number of vessels in this sensitive sea area makes it environmentally relevant to minimize the use of biocidal antifouling paints. In this study, the viability of foul-release coatings (FRCs) as a replacement for biocidal coatings has been assessed for this region. To this end, the efficacy, market barriers and environmental sustainability of silicone FRCs were evaluated in comparison to conventional copper coatings. Coated panels were exposed statically over a 1-year period at three locations in the Baltic Sea region to assess the long-term performance of a biocide-free FRC and two copper coatings during worst-case conditions.

The silicone FRC was found to perform equally well or significantly better than the copper coatings, regardless of exposure site or time point. Potential market barriers, most importantly concerning end-user attitudes and current regulations were identified and discussed. Finally, even though most silicone FRCs on the market are biocide-free, a review of the literature regarding potential toxic effects and the identity and environmental fate of leachables shows that they may not be completely environmentally benign, simply for the lack of biocides. Nonetheless, FRCs are still substantially less toxic compared to biocidal antifouling coatings. The demonstrated efficacy and reduced environmental impact of silicone FRCs thus make them a viable option to biocidal coatings for both ships and leisure boats trafficking the Baltic Sea region.