Heavy metals in rivers and soils of central Chile

Industrial and domestic waste waters in Chile are discharged without previous treatment into rivers and other inland waters which are used to irrigate agricultural lands. The present study reports on results obtained when analyzing inland waters for Cd, Cu, Zn, Hg and As. Copper content was found to be high in most of the rivers studied and its sources were identifiable copper mining wastewaters. Cadmium and Zn levels are above accepted levels in some instances, whereas Hg and As content of river waters under study studied were found to be within accepted levels. The more reactive chemical forms of heavy metals in soils irrigated with polluted waters, as determined by sequential extraction, were found to be the most abundant ones.,These forms are easily bio-available. (C) 1998 IAWQ. Published by Elsevier Science Ltd.