A method for differentiating trace metal species on the basis of relat
ive lability has been applied for Pb, Cd, Zn, in microenvironments of
the Gulf of Elefsis. Species are classified as ''very labile'', ''mode
rately labile'', ''slowly labile'' and ''inert'' depending on the char
acteristic time scale of the measuring technique using differential pu
lse anodic stripping voltammetry (DPASV) and the retention on Chelex-1
00 resin in successive column and batch procedures. The results show t
hat in two extremely different microenvironments (with S of about 17 p
arts per thousand and similar to 45 parts per thousand) the slowly lab
ile and inert fractions prevail particularly at the surface layer, whe
reas in the main water body of the gulf the very labile fraction is th
e predominant one. However at the thermocline and below it the ''inert
'' fraction increases considerably paralleling, broadly, the particula
te metal distributions.