Zinc inputs to coastal waters from sacrificial anodes

The importance of sacrificial anodes as a source of zinc inputs to marinas, harbours and estuaries has been investigated. The study shows that the increase in dissolved zinc levels where anodes are used is likely to be small in relation to the current Environmental Quality Standard (40 μg Zn l−1). Nevertheless, sacrificial anodes can be expected to lead to measurable increases in concentrations of dissolved zinc in marinas and to a lesser extent, in nearby estuary areas. The local increase in concentrations of dissolved zinc near open marinas may be between 2 and 5 μg l−1, with levels in enclosed marinas being as high as ca. 20 μg l−1. Increases in zinc concentrations in marina sediments of up to twice background levels (by up to 200 μg g−1) were observed.