Abstract
We performed an ecological risk assessment on antifouling paints that contain copper pyrithione (CuPT) which are applied to vessels visiting Tokyo Bay. The Margin of Exposure (MOE = NOEC/EEC) method was used in the risk assessment, with the NOEC set to 0.25μg/L (Skeletonema costatum Growth inhibitor). The EEC was estimated by using a chemical fate model developed at AIST. The Uncertainty Factor (UF) was set to be 100 for this ecological risk assessment. The calculation period was for year 2008, when antifouling paints containing TBT will be substituted for alternative paints, such as those containing CuPT.In this study, the ecological risk was found to be significant because the MOE values were below the UF in the commercial ports of Yokohama, Tokyo and Chiba, but not throughout the entire study area.In Tokyo Bay, the ecological risk posed by CuPT in antifouling paints is at its greatest in the Yokohama port area. In a bid to reduce this risk, we estimated potential reduction in CuPT concentration in high MOE area, such as Yokohama port. This, by the effects of dispersion using water flow and by enhancing photodegradation.
