Abstract
With increasing demand for recycling of waste by-products generated from agricultural and industrial activities, soil is not only considered as a source of nutrients, but also as a sink for the removal of contaminants from these waste materials (Power and Dick, 2000). As land treatment becomes an important waste management practice, soil is increasingly being seen as a major source of trace elements reaching the food chain, mainly through plant uptake and animal transfer. Such waste disposals have led to significant build up of a suite of trace elements, such as arsenic (As), cadmium (Cd), copper (Cu), chromium (Cr), fluorine (F), mercury (Hg), lead (Pb), selenium (Se), and zinc (Zn). Entry of soil- borne trace elements into the food chain depends on their amount and input sources, reaction with soil components, the properties of the soil, the rate of uptake by plants and the extent of ingestion by grazing animals.