Assessment of Petroleum Hydrocarbons and Heavy Metal Pollution in Soil, Water and Plants Adjacent to AL-Najaf Oil Refinery, Iraq.

The environment near oil refineries is at high risk of contaminate. This study assessed the levels of total petroleum hydrocarbons (TPH) and heavy metals (Cd, Pb, Ni) in soil, groundwater, and wheat crops around Al-Najaf Oil Refinery. Samples were collected from four directions. Results revealed severe contamination, with TPH and heavy metal concentrations at the refinery center and up to 1 km away significantly exceeding WHO and UNEP safety limits. This contamination extended to groundwater and accumulated in wheat grains, posing a serious threat to ecosystem and public health. The study highlights the urgent need for remediation and monitoring. Also the results showed that the highest values of cadmium, lead and nickel for the depth of D1 reaching 6.12 mg kg-1, 269 mg kg-1 and 117 mg kg-1, respectively, at the pollution center, and that all cadmium, lead and nickel concentrations were higher than the critical limit of 3 mg kg-1, 100 mg kg-1 and 50 mg kg-1, respectively, specified by the World Health Organization at the oil refinery center and at a distance of A1 for the depth of D1 and D2, respectively. The results also showed that the maximum values for cadmium, nickel and lead in the water samples reaching 0.032, 0.44 and 5.3 mg L-1 respectively, and that an average of values of cadmium, lead, and nickel in wheat crop samples reaching 0.49, 25.7, and 112.78 mg kg-1 plant respectively. All the values were higher than the limits allowed according to the World Health Organization.