Abbas S. S AL-Wotaify - Agriculture Coll. Al-Qasim Green Univ.Iraq

This research included study of some heavy metals for surface soil samples polluted by the oil Samawa refinery residues in southern Iraq, and the assessment of the state of pollution and potential ecological risks according to some equations of simple and composite pollution indicators(PI and NIPI respectively), as well as the potential ecological risk index(Er) for soil samples pollution by each of metal, and the comprehensive potential ecological risk index(RI) for Pb, Ni and Cd combination of each soil sample. The contaminated soil content of Pb between 177.56-300.71mg kg-1, Ni between 69.46 -89.67mg kg-1, and Cd between8.00-20.10mg kg-1, compared with non-contaminated soil by Pb was 0.70, Ni 0.12 and Cd 0.32mg kg-1. As a result of contaminated soils in high levels of these heavy metals, the simple pollution index (PI) was between 235.65-429.58for Pb, Ni579.33-747.25 and between 25.00-62.81of Cd. The values of PI led to an increase in the values of the Newmerow integrated pollution index(NIPI) to reach 486.69 of Pb, Ni 876.45 and 69.72 of Cd.The potential ecological risk index(Er) was for Pb between1167.20- 2081.10, Ni between 2849.15-3736.25 and Cd ranged between740.40 -1884.30 in each of samples soil polluted in the oil residues. Consequently,these results the overall comprehensive ecological risk index(RI) for Pb, Ni and Cd in each polluted soil sample was ranged between5081.35-7465.25, exceeding all limits and levels of environmental pollution of heavy metals at the highest levels.

Potential ecological risk, Heavy metals, Soil pollution, Oil wastes