DETERMINATION OF HEAVY METALS AND TOTAL PETROLEUM HYDROCARBONS IN SOIL SAMPLES AND PLANT LEAVES AROUND OIL REFINERIES LOCATED ON ERBIL-GWER ROAD

Several refinery complexes exist in the Kurdistan Region of Iraq that produce various kinds of petroleum products. During the refining process, different types of gases, metals, hydrocarbons, and liquids are discharged into the environment. This study aimed to determine the concentration of eight heavy metals in soil and plant leaves collected around the refineries along Erbil-Gwer Road on two occasions throughout the study period. Additionally, we aimed to evaluate the levels of Total Petroleum Hydrocarbons (TPH) in the soil samples from the area. The results of the analysis revealed significant differences (P<0.05) in the concentrations of Pb, Ni, Cd, Cr, As, and Mn between the dry and wet seasons in the soil samples. However, no significant differences were observed for Cu and Zn between the two seasons. The levels of metals for both periods were as follows: Mn> Cr> Zn> Ni> Cu> Pb> As> Cd in successive forms. Regarding the plant leaves, significant differences (P<0.05) were found between the study periods for Pb, Cu, Zn, and Cd, whereas no significant differences were observed for the other metals. Furthermore, the concentration of TPH in the soil samples located alongside the refinery effluent stream was higher compared to the other areas.