Chemical sequential extraction as decision-making tool: application to municipal solid waste and its individual constituents

This work deals with the search for the origins and chemical ‘forms’ of Cd, Cu, Cr, Ni, Pb and Zn in municipal solid waste (MSW). Total metal analyses and chemical sequential extraction are performed on 14 constituents of MSW and on a reconstituted MSW. Those constituents which have a major influence on the total trace metal load of the waste are identified. The influence of the chemical ‘forms’ of trace metal in these constituents can easily be recognised on the sequential extraction diagram of the whole waste. Because of the importance of the quantities of metal soluble at pH 5, lead and zinc could have a major environmental impact. Particular risks of contamination of organic matter by trace metals bound to fine particles are also underlined. The results show that chemical sequential extraction is a precious operational tool.