While not all metals in Soil--plant systems are inherently toxic, particularly in low concentrations, there is an increasing incidence of metal pollution from aerial fallout, spoils, wastes and agricultural amendments including sewage sludge. Toxic Metals in Soil--Plant Systems 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 and pedological concentration mechanisms are discussed, including cation exchange and anion adsorption onto different soil materials. The book is divided into two sections; the first part discusses the sources and fates of metals in ecosystems, with an up-to-date review of the processes which control metal speciation in soils, metal uptake mechanisms, and plant responses to toxic metal concentrations in soils. A clear understanding of these processes and their interactions in soil is necessary before it is possible to instigate amelioration and restoration programmes for metal-contaminated land. In the second part of the book, a selection of case studies are presented which discuss metal toxicities and metal cycling in a range of different ecosystems, including managed agricultural systems, deciduous woodland, upland heather moorland, and tropical wetlands. In these studies a number of current issues are addressed, including the setting of toxicity thresholds for safe sewage sludge application to agricultural land, the accumulation of soil metals over time in aerially impacted systems, and metal transfers between ecosystem compartments, which are of particular concern in food crops. Providing an integrated view of toxic metals both in the soil and associated growing plants, this book covers a wide range of topics including agriculture, soil science, ecology and forestry and will be of use to researchers and environmental consultants working in these fields.