Publisher's Synopsis
This book describes the extent of worldwide contamination by four important toxic elements: arsenic, cadmium, lead and mercury. It provides details on pathways and rates at which these four elements cycle in the air, in soils, through crops and native ecosystems and in rivers, lakes and oceans. New contributions are made on oceanic and atmospheric occurances and on areas of long residence times (sinks) such as lake sediments, deep oceans and forest humus layers. It discusses the sources of these four elements and estimates the relative contribution to global and regional cycling of natural versus man-made sources. The need for a fuller understanding of sources to human populations and to particular high risk groups is emphasisd, for example, the exposure of young children to lead and of elderly females to cadmium in cetain areas of Europe. Food sources to humans are discussed with emphasis upon acquatic based food chains, including fish and shellfish.;The particular problms of developing countries are considered and contrasted with those of the industrialised world. The recurring problems of mercury coated grain and uncontrolled pollution from smelters and mining operations are set against the insidious problems of long distance regional distribution of metals via polluted air masses. The book does not simply look at what we already know, but identifies what we need to know in order to build regional and global models of cycles of toxic elements with confidence.
