ZINC INPUTS TO COASTAL WATERS FROM SACRIFICIAL ANODES

The importance of sacrificial anodes as a source of zinc inputs to mar inas, harbours and estuaries has been investigated. The study shows th at the increase in dissolved zinc levels where anodes are used is like ly to be small in relation to the current Environmental Quality Standa rd (40 mu g Zn l(-1)). Nevertheless, sacrificial anodes can be expecte d 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 mu g l(-1), with levels in enclosed marinas being as h igh as ca. 20 mu g l(-1). Increases in zinc concentrations in marina s ediments of up to twice background levels (by up to 200 mu g g(-1)) we re observed.