During recent years, rapid increase in population coupled with fast urbanization is causing serious environmental problems, including the production and release of considerable amounts of toxic waste materials into environment. Among all the heavy metals, arsenic (As) and cadmium (Cd) are highly bioactive and toxic elements and their presence at elevated levels in soils and drinking water is threatening the food safety and human health. This book describes the consequences of As and Cd toxicity in soil, plants, animals and humans. "