What is the connection between salinity and anti-fouling paint?
Salinity levels vary greatly between different harbors and locations along the coast and there are different types of antifouling paint allowed in the different areas.
In a study regarding the correlation between salinity and anti-fouling paint, Ytreberg et al. (2020) investigate two aspects of the subject. The first aspect is that higher salinity levels result in greater biofouling problems. The second aspect, which is the focus of the study, is that higher salinity levels cause biocides to leach from the paint at a faster rate.
The study measured the release rate of biocides for eight different coatings in four different harbors with varying salinity levels. It was found that the release rate, particularly of copper, tended to be higher in higher salinity levels, thereby reducing the effectiveness of the paint against biofouling. The conclusion drawn was that coatings with higher copper content did not show a significant improvement in effectiveness against biofouling in higher salinity levels.
The authors claim "This result suggests there is potential for a ~ 80% reduction in Cu release rates from the highest leaching antifouling products for recreational vessels in the Baltic Sea and Kattegat area without any efficiency loss."
“It is of utmost importance to address the issue of using paint that is more toxic than necessary” said Erik Ytreberg, Department of Mechanics and Maritime Sciences, Chalmers University of Technology, in an interview.
Although it may be difficult to alter the increased risk of biofouling at higher salinity levels, unnecessary use of environmentally hazardous anti-fouling paint can be changed. However, developing sustainable and efficient anti-fouling paints is challenging when the surrounding ocean conditions are not known. By increasing knowledge of salinity in coastal areas and harbors, we can aid researchers in developing new, more environmentally friendly and effective anti-fouling products than the current ones.
