Leaching of Cu and Zn from discarded boat paint particles into tap water and rain water

We studied the leaching of copper and zinc from particles of discarded boat paint added to tap water (pH 7.3) and rain water (pH = 4.7), simulating conditions encountered during the hosing or runoff of antifouling waste. Leaching rates appeared to be diffusion-controlled and were greater in rain water than in tap water and were greater for Zn than for Cu. After a period of 120 h, between about 0.5% and 3% of total Cu and 5–30% of total Zn had been released to the aqueous phase. These observations suggest that Cu and Zn mobilised from fine antifouling particulates during washdown or rainfall events may be important contaminants of runoff and soils in the vicinity of boat repair facilities.

Research highlights
► Copper and zinc are mobilised from boat paint particles suspended in fresh waters.
► Leaching rates appear to be diffusion-controlled.
► More rapid metal leaching occurs in rain water than in tap water.
► Zinc is more readily mobilised than copper.