TRACE-METAL SPECIATION AND RESEARCH IN MARINE GEOCHEMISTRY

In order to precise the origin and behaviour of trace metals associate d with coastal marine sediments, marine geochemists frequently utilize various methods of sequential extraction. The main objective is to te st the potential mobility / stability of particulate metals in the nat ural environments. Several examples are presented in the article, name ly: i/ Exchangeable Pb from podzolic soils of the drainage basin of a lagoon which sediments and phreatic waters are for a large part inheri ted from the surrounding soils; ii/ Evolution of particulate metals in an estuary; iii/ Mobility of metals at the sea bottom interface; iv/ Role of amorphous components of estuarine sediments and suspended matt er; v/ Effects of dredging activities on solubility of metals in an es tuary; vi/ Behaviour of heavy metals in lagoons. Main results obtained from the extraction procedures are described, as well as particular d ifficulties encountered when applying some classical methods,