MICROAUTORADIOGRAPHY (WITH COMBINED LIQUID SCINTILLATION) APPLIED TO THE STUDY OF TRACE-METAL UPTAKE BY SUSPENDED PARTICLES - INITIAL RESULTS USING NI-63 AS A TRACER

We report the development of a microautoradiographic method for the st udy of trace metal-particle interactions in natural waters. This techn ique, in combination with conventional liquid scintillation counting m ethods, was applied to surface water samples from the Belgian coastal zone and Scheldt estuary. Ni-63 was used as the metallic radio-tracer. Ni partitioning in our experimental system was shown to be a primaril y abiotic process, driven by passive sorption reactions and limited in extent on a 24-h time scale by the slow reaction kinetics of Ni. Smal l particles (< 1 mum) were important as sorption sites, while large pa rticles exhibited variable and particle-specific scavenging potential.