This study discusses the processes of trace metal cycling in contaminated ecosystems under conditions where their concentrations become toxic through high loading rates, long-term exposure or altered environmental conditions. Other environmental concentration mechanisms are discussed, including cation exchange and anion adsorption on different soil materials. Divided into two sections, the book first reviews the current understanding, not only of sources and fates of metals in ecosystems, but also the processes which control metal speciation in soils, metal uptake mechanisms, and plant...