Zinc concentrates are UVCB’s, consisting of a zinc mineral (e.g. sphalerite- ZnS in most cases) with some other metals (e.g. Pb, Cd, Cu, Ni, As, ...) in lower concentrations. These metals are all bound to a varying degree into the minerals matrix, which results in a varying degree of potential for solubilisation of these metals in aqueous media. The hazard potential of the metals contained in the zinc concentrate should therefore take into account the capacity of the metals to be released. For more details, please consult attached "explanatory note"