APPLICATION OF DGT TECHNIQUE IN SPECIATION OF TRACE METALS IN A STRATIFIED ESTUARY

An evaluation of Diffusive Gradients in Thin films (DGT) technique for speciation of trace metal(oid)s in relation to their bioavailability was performed in the stratified Krka river estuary (Croatia). Chelex-100 based DGT probes with both open and restrictive pores were used for speciation of Zn, Cd, Pb, Cu, Ni and Co, while iron-hydroxide resin was used for As speciation. The percentage of DGT-labile concentrations varied from>90 % for Cd, down to ~20 % for Cu. The difference between open- and restrictive-pores was unexpectedly small. An increase of total dissolved and DGT-labile As concentrations was observed with increase of salinity