Heavy metal determinations in algae and clams and their possible employment for assessing the sea water quality criteria

An empirical criterion for a possible classification of sea water quality i s proposed. It is based on the knowledge of metal content in algae (Ulva Ri gida) and clams (Tapes Philippinarum), two species present in marine ecosys tems. The elements considered are Hg, Cu, Pb, Cd, Zn. The analytical techni que employed is Differential Pulse Anodic Stripping Voltammetry (DPASV) in the case of Cu, Pb, Cd, Zn, while the determination of mercury is obtained by the Cold Vapour Atomic Absorption Spectroscopy (CV-AAS) technique with S nCl2 as reducing agent. The analytical procedure has been verified on three standard reference materials: Sea Water BCR-CRM 403, Ulva Lactuca BCR-CRM 279 and Mussel Tissue BCR-CRM 278. For all the elements, in addition to det ection limits, accuracy and precision are given: the former, expressed as r elative error (e), and the latter, expressed as relative standard deviation (s(r)), were in all cases lower than 6%.