Research article

The effect of the Garraf oil field on soil pollution with some heavy metals (Pb, Cd, Cr, Co, Ni) for the surrounding area of the field

Murtada Suhail Abed Al-Rikabi and Mahdi Wasmi Sahib Al-Aydi

Online First: November 08, 2022


To estimate the state of pollution with some heavy metals (lead, cadmium, nickel, chromium and cobalt), a study was applied to find out the effect of Al-Gharraf oil field in Dhi Qar governorate on soil pollution with heavy metals in the surrounding areas of the field. Soil samples were collected from three sites, which are 500, 1000 and 1500 m away from the source of pollution, in addition to the fourth (control) site in the northeastern part of the oil field. Samples were collected at depths of 0-20 and 20-40 cm and from the southeastern and northwestern northeastern parts. The results of the study have been showed a high total concentration of heavy metals lead, cadmium, nickel, cobalt and chromium in the soil of the study sites in the southeastern part of the field at depth 0- 20 cm, which is 500 m (first site) from the oil field. It has been recorded 347.40, 11.09, 116.56, 68.78, and 98.45 mg kg-1 soil, respectively, which is higher compared to its concentration in the soil of the fourth site, where was 50.87, 1.25, 12.76, 5.77 and 5.98 mg kg-1 soil, respectively. The concentration of heavy metals in northwestern part of the field has the same depth, the nearby sites were recorded. However, it has been reached 116.28, 3.08, 62.70, 22.56 and 37.54 mg kg-1 soil, respectively, which is higher compared to the second depth and in both directions. The concentration of heavy metals in the soils of the study sites close to the source of pollution has increased above the international limits allowed by the World Health Organization (WHO, 2007) in the southeastern part of the oil field, except for chromium, which did not exceed the permissible limits. The study showed that human activity is the main source of high pollution standards (CF, PLI, Igeo). The mean values of the CF pollution factor for lead, cadmium, nickel, cobalt and chromium in the soils of the nearby sites (the first site) of the oil field and in the southeastern part were 6.83, 8.87, 9.13, 11.92 and 16.46, respectively. The value of the CF pollution factor indicates that a considerable contamination occurred to very high contamination. In the northern part, the CF pollution factor recorded low values for soil close and far sites compared to the southeastern part of the Al-Gharraf oil field. The average values of the Pollution Load Index (PLI) for the soil of the sites near the field and in the southeastern part reached the highest value of 10.16, which is higher compared to the far sites, which is recorded 3.98. In the northwestern part, the pollution load index (PLI) values decreased compared to the southeastern part. The values of the PLI <1 for the study soil sites indicated a state of deterioration in the soils of the study sites and for the northwestern and southeastern parts and the deep pasture.

Keywords

Garraf oil field, soil pollution, heavy metals, Pb, Cd, Cr, Co, Ni