Life cycle assessment of the use of marine biocides in antifouling paint A comparison of the environmental profiles between conventional copper-based and innovative Selektope paint

Cuprous oxide-based antifouling paint is now the most common type in use, especially in the shipping industry. Anti-fouling paints prevent or slow down the growth of organisms attached to the hull, in order to improve a vessel’s performance and durability. However, copper is a scarce resource and never can be retrieved or recycled after leaching into the sea. The need to protect sensitive marine areas from elevated levels of copper and to reduce the amount of copper emitted into the environment has led to the search for an alternative. A new product has been developed by I-Tech as a replacement for cuprous oxide in antifouling paint, trademarked as Selektope. It is based on biological knowledge and does not kill the target organism but instead deters it away from attaching to the ship hull. It is an organic synthetic biocide that can degrade in the marine environment and its mode of action makes it effective at very low concentrations (about 0.1% mass of paint). This is in sharp contrast to copper-based paints which need to be 40 – 60% copper by mass. This master thesis aims to compare the sustainability profiles of the innovative Selektope paint system with traditional copper-based paint. Life-Cycle Assessment (LCA) is performed to analyse and compare the energy demand, global warming potential (GWP), and marine aquatic ecotoxicity potential (MAETP) of the two paint system. The effect of ecotoxicity on the marine environment on the use of cuprous oxide and Selektope has also been studied using MAMPEC model. Despite some of uncertainties from assumptions and data availability, the results from LCA indicate an overall higher environmental impact from copper-based paint than from Selektope paint, in terms of all impact categories. The production of cuprous oxide appears to be the dominant burden in the life-cycle impact of copper-based paint, except that the release of copper during user phase has a much larger contribution to the MAETP. The impact generated by the Selektope paint has a relatively even distribution among different phases. However, the choice of transportation method can largely influence the result even though it would still be insignificant compared to copper-based paint. The results from the ectoxicological risk analysis show no potential risk in the leaching of both copper and Selektope.