Assessment of Environmental Pollution by Certain Heavy Metals in the Soil of the Northern Refineries Company and Some Adjacent Soils

• Sami Younes Fadel1, Basim Shakir Obaid Al-Obaidi2

  Author

This study was conducted to assess soil contamination with heavy metals in the Baiji district of Salah al-Din Governorate. The study involved collecting 14 surface soil samples at a depth of 0 –20 cm from inside and outside the Baiji oil refinery and neighboring areas. Some chemical properties of the study soil, especially texture, as well as chemical properties, were determined, and the total content of heavy metals was measured using an atomic absorption spectrometer (AAS). Environmental pollution indices, including the pollution factor and enrichment factor, were also calculated to assess the severity of contamination. The most important findings can be summarized as follows Total nickel exceeded the permissible limit of 50 mg kg⁻¹ at all sites, with concentrations of 166.96 – 92.20 mg kg-1 Total cadmium also recorded localized exceedances of the 3 mg/kg limit, with values reaching 5.16 mg/kg. In contrast, total concentrations of lead, copper, and cobalt remained within standard limits, indicating that nickel and cadmium are the primary pollutants associated with petroleum activities in the study area. Regarding the pollution factor index, the average values of heavy metals across all sites were as follows: lead, cadmium, nickel, cobalt, and copper had values of 1.5087, 4.7517, 3.9104, 0.8051, and 3.8887mg kg⁻¹, respectively. As for the enrichment factor index, the values of the elements in the same order were: 1.3757, 4.3435, 3.6607, 0.6909, and 3.5819, mg kg⁻¹ respectively. The results regarding pollution criteria indicate that nickel and cadmium represent the elements with the highest cumulative risk.

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