Due to the presence of organic compounds, heavy metals, various hydrocarbons, organic solvents, aromatic compounds, linear formaldehyde, fats, and grease, petroleum products are among the most life-threatening factors in the ecosystem. Therefore, this study was conducted to examine the soil surrounding Shazand Oil Refinery Complex in Markazi Province, Iran, and assess the concentration of various heavy metals, including Fe, Cd, Mn, Cr, Zn, Cu, Ni, and Pb (mg/kg) in surface soils of different land uses. In so doing, the soil contamination rates and potential ecological risks of the soils were assessed using I_geo, IPI, EF, PLI, NIPI, and PERI. Based on the results of the I_geo index, moderate levels of Cd and Pb concentration (0.633 and 0.921, respectively) were observed. Based on the NIPI values, Cd (1.65) and Pb (2.01) could be classified as causing moderate pollution levels. Moreover, based on its E_i value, Cd (69.8) could be considered as posing a moderate ecological risk. Besides, the EF values of Cd (2.69), Pb (2.02), and Zn (1.41) indicated that they have minor enrichment. Besides, the IPI of the studied soil samples suggested that the soils could be categorized as low polluted, while the pollution load index (PLI) indicated that the whole research area could be considered as non-polluted. Based on the Pearson correlation coefficient, PCA, and HCA, it was decided that the heavy metals in the study area mainly originate from three different sources. Moreover, no significant difference was found between different land uses regarding the contamination of surface soil samples. However, in the long term, due to the impact of anthropogenic activities, discharge of Cd, Pb, and Zn to the environment might result in their accumulation in soil. In conclusion, it is suggested that soil analyses be included in future studies for determining the impact of the number of bioavailable metals.

由于有机化合物、重金属、各种碳氢化合物、有机溶剂、芳香族化合物、线性甲醛、脂肪和油脂的存在，石油产品是生态系统中最危及生命的因素之一。因此，本研究旨在检测伊朗 Markazi 省 Shazand 炼油厂周围的土壤，并评估各种重金属的浓度，包括 Fe、Cd、Mn、Cr、Zn、Cu、Ni 和 Pb（mg/ kg) 在不同土地用途的表层土壤中。在此过程中，使用I _geo、IPI、EF、PLI、NIPI 和 PERI评估了土壤的土壤污染率和潜在生态风险。基于I _geo的结果指数中，观察到中等水平的 Cd 和 Pb 浓度（分别为 0.633 和 0.921）。根据 NIPI 值，Cd (1.65) 和 Pb (2.01) 可归类为造成中等污染水平。此外，基于其E _i值，Cd (69.8) 可被视为构成中等生态风险。此外，Cd (2.69)、Pb (2.02) 和 Zn (1.41) 的 EF 值表明它们具有轻微的富集。此外，所研究土壤样品的 IPI 表明土壤可以归类为低污染，而污染负荷指数（PLI）表明整个研究区域可以被视为未受污染。根据 Pearson 相关系数、PCA 和 HCA，确定研究区的重金属主要来源于三个不同的来源。此外，在表层土壤样品的污染方面，不同土地用途之间没有发现显着差异。但从长远来看，由于人为活动的影响，Cd、Pb、Zn 向环境排放可能会导致其在土壤中积累。