Chemical speciation of Cu, Zn, Pb and Cd in rain water

A scheme for metal speciation which combines physical characterization by size fractionation and chemical characterization by dissociation kinetics has been used to characterize trace metal species in a sample of rain water. The lability of the metal species in each size fraction of ultrafiltration was determined by differential pulse anodic stripping voltammetry and by ion-exchange with Chelex-100 resin, using both the column and the batch technique. Most of the Pb, Cd, Cu and Zn soluble species were ASV-labile and Chelex-labile, and fell in the small size fractions (