Today, heavy metal pollution has become one of the most widespread and serious problems. In addition, soil and rivers contaminated with toxic metal pose a major environmental and human health problem and has been attracting considerable public attention over the last decade. Human activities have introduced numerous potential hazardous trace elements into the environment since the industrial growth. Other sources of heavy metal contamination associated with agricultural soil are sewage sludge, fertilizer, and pesticides (Alloway and Ayres, 1993).