The Potential Ecological Risk Index method was proposed by Hakanson (1980) from a sedimentology perspective to assess the characteristics and environmental behaviour of heavy metal contaminants. In further consideration of the heavy metals, the Hakanson method assesses their potential ecological and environmental effects with toxicology. The method comprises a single contamination coefficient, the toxic response factor for heavy metals, a comprehensive contamination measure as well as a Potential Ecological Risk Index.