Metal Speciation Studies in a Brakish/Marine Interface System

The paper presents some interesting results of metal speciation studies employing Anodic Stripping
Voltammetry (ASV) applied in a dynamic natural system such as the brakish – marine interface formed
between the polluted waters discharged by the Koumoundouros lake and the marine ones of the Gulf
of Elefsis.
The distributions and behaviour of various forms of Pb, Cd and Zn have been followed seasonally. Four
categories of dissolved species were identified (very labile, moderately labile, slowly labile and inert),
as well as particulate species. It was found that their relative contribution and patterns are determined
by three main factors: salinity, pH, and the presence of dissolved organic carbon. Increasing salinity
stimulates formation of very labile chloro-complexes, while increasing pH stimulates the formation of
inert species and particulates. A considerable part of slowly labile species seems to be metal complexes
with organic ligands.