Heavy metals: sources and environmental presence.

The Istituto Superiore di Sanità has for many years been involved in the problem of environmental pollution caused by heavy metals. A brief review of the sources of this pollution is first presented which also includes the presence in nature of some heavy metals which are among the most dangerous. Data gathered by the authors is then presented from sampling of the emissions of urban solid waste (USW) incinerators and from environmental monitoring programs in different areas in Italy according to four categories: urban, industrial, rural and mixed.