Determining The Concentration of Heavy Metals in Soil Contaminated with Crude Oil at Al-Kasak and Al-Qayyarah Sites According to Environmental Indices of Pollution

Contaminated soil samples were collected from Al-Kasak refinery and Al-Qayyarah refinery in western and southern Nineveh, at specific distances in six dimensions (0, 50, 100, 150, 200, 300) meters from the source of pollution, to study the concentrations of heavy metals Pb, Mn, Ni, Cd, and the effect of oil refinery pollutants on some soil pollution standards, in addition to some physical and chemical properties of the soil and their concentrations. The results showed an increase in the concentration of heavy metals in the soil near the sources of pollution, with cadmium significantly superior to Al-Qayyarah site over Al-Kasak site (491.744) mg/kg, and lead, nickel and manganese recorded a higher concentration at Al-Kasak site compared to Al-Qayyarah site (166.356, 114.687, 36.487) mg/kg, respectively, and the order of mineral elements in the two study sites was Cd>Pb>Ni>Mn. As for the Contamination Factor (CF), it was Cd > Pb > Ni > Mn with values of 684.50, 9.91, 5.13, and 0.1701, where the concentration factor was highly polluted for cadmium and lead, and with significant contamination for nickel, while manganese was low in contamination, cadmium recorded severe pollution at Al-Qayyarah site compared to Al-Kasak site, while lead, nickel and manganese recorded significant contamination at Al-Kasak site compared to Al-Qayyarah. In addition, the pollution load index (PLI) was at the level of 5.81, 4.67 highly polluted at D1 and D2, while the rest of the percentages were at the level of 2, moderate pollution, Al-Kasak site had the highest pollution (PLI) value of (6.28), while the ecological risk (ER) averaged (20534.88, 16896.71, 19867.11, 19063.14, 18721.07, 18888.61), which indicates that all the sites had very high pollution, and the ecological risk index was also within the limits of very high pollution, with the highest value on D1 recorded (20568.45), and the potential ecological risk of cadmium was very high at Al-Qayyarah site with a value of (19410.95) compared to Al-Kasak site, where the ecological risk of lead, nickel and manganese was very high, and the ecological risk indices for Al-Qayyarah site were high compared to Al-Kasak site. The aim of the study is to estimate the concentration of heavy metals, according to environmental indices and the impact of oil refineries on the ecosystem in raising the level of heavy metal concentration.