Kinetic Studies of Metal Speciation Using Chelex Cation Exchange Resin: Application to Cadmium, Copper, and Lead Speciation in River Water and Snow

The kinetics of cadmium(II), copper(II), and lead(II) speciation in river surface water and snow samples were measured using the Chelex batch technique and model solutions containing the metal ions and the complexants EDTA, nitrilotriacetic acid (NTA), and fulvic acid. The metal ions were measured by inductively coupled plasma mass spectrometry. Rates of metal uptake were analysed by the iterative deconvolution method. In the presence of excess EDTA or NTA the metals formed slowly dissociating complexes. In the presence of fulvic acid, the metals formed strongly bound complexes with a range of slow dissociation rates. The fulvic acid:metal ion ratio and the extent of occupation of binding sites in fulvic acid on the lability of metal-fulvic acid complexes was important. There are 55 references.