Potential Ecological Risk Assessment Model for Heavy Metal Contamination of Agricultural Soils in Mining Areas

Abstract

The aim of this work was to develop a potential ecological risk index to be used as a diagnostic tool for heavy metal contaminated agricultural soils control purposes in mining areas.Taking consideration that the main-road for ecological risk of heavy metal contamination of soil is soil-vegetation-man.The environmental bioavailability largely determines the environmental impact of metal contaminated soils.Using environmental bioavailability explain the environmental toxicity sensitivity of the heavy metals in the soil-vegetation-man ecological system.The model is following: RI=Σmi=1Eri,with Eri= Cif×Tib×Tie.RI= the requested potential ecological risk index for soil;Eri = the potential ecological risk factor for the given substance(i);Cif= the degree of contamination,Cif=Ci/ Cio,Ci= the metal concentration in the soil,Cio= the metal concentration for samples from referring area;Tie= the element toxic-response factor for the given substance: Zn=1,Pb=4,Cd=15,Cu=2,Cr=11,Ni=3.Tib=(Rib / Pib)1/2;Tib =the environment bioavailbability ratio factor,Tib =(Rib / Pib)1/2,Rib =[water soluble fraction + exchangeable fraction/total concentration of the metal in soil](100%] for the samples of contaminated soil,Pib=[water soluble fraction + exchangeable fraction/total concentration of the metal in soil]×100%] for samples from referring area.