Environmental Impacts of Alternative Antifouling Methods and Use Patterns of Leisure Boat Owners

Purpose Leisure boaters in the Baltic Sea apply more copper as antifoulant than needed and permitted. Initiatives have been started to identify efficient means making boat owners comply with regulations through changed consumer behavior. We compare the environmental impacts of conventional and alternative antifouling methods, using Life Cycle Assessment methodology. Methods Two non-toxic methods were compared with biocide paint. To study the influence of boat owner use patterns, paint and brush washer scenarios (e.g., different paints, amounts, and maintenance) were created based on current use and recommendations. The functional unit was an average Swedish leisure boat kept fouling free for 1 year and impact categories studied were freshwater eco-toxicity and greenhouse gas emissions. Production of paints, fuel, electricity, and material used in the non-toxic methods was included. Sensitivity analysis was performed regarding the characterization method for toxicity, the fuel consumption data, and the copper release data. Results and discussion The non-toxic methods, hull cover and brush washer, performed best, but a trade-off was identified when the brush washer was located further away from the home port, when additional transportation increased greenhouse gas emissions. The resources needed for the non-toxic methods (production of materials and electricity used) cause considerably lower toxic emissions than paint. In the paint scenarios, using less paint and cleaning the boat over a washing pad with water treatment reduces aquatic emissions significantly. Fuel-related emissions were consistently lower than paint-related emissions. In the best-performing paint scenario, fuel- and paint-related emissions represented 26 and 67% of total emissions, respectively. Conclusions The non-toxic methods hull cover and brush washers lead to lower emissions, especially when brush washers were located close to the home port. Lacking such infrastructure, “painting less” is a way to reduce emissions, by using lower amounts of paint and painting less frequently. More widespread use of these antifouling strategies would considerably reduce copper emissions from leisure boating to the Baltic Sea. We suggest that support to marinas for investments in brush washers and washing pads should be further developed to enable boat owners to choose more sustainable antifouling methods and that information campaigns on the combined economic, health, and ecosystem impacts of antifouling are especially designed for boaters, marinas, market actors, and policy makers for a change to take place towards more sustainable practices.