Statistical Modeling of Environmental Pollution of Soil Around Oilfields Using Geochemical Indices

The importance of studying Quaternary deposits has increased to such an extent that it now occupies a significant part of research in different parts of the world. In oil-rich countries, including Iran, pollution caused by oil industry activities such as drilling and exploitation has seriously threatened the sediments and soils around these areas. The Abteymour oilfield is one of the big fields in southwestern Iran, located in the area of agricultural lands. As a result, it is essential to evaluate its environmental effects. In this research, ۳۳ surface soil samples were collected, and in addition to measuring the concentration of heavy metals, some physical and chemical characteristics of the soil were measured. Statistical analyses such as correlation coefficient, principal component analysis, and cluster analysis were used to identify the source of pollutants. Environmental geological indices such as geoaccumulation index (Igeo), enrichment factor (EF), contamination factor (Cf), and Nemro integrated pollution index (NIP) were used to determine the level of heavy metal pollution. The cluster analysis results stated that the studied elements were clustered in two groups. Also, the factor analysis results showed that ۸۹% of the variation of the studied parameters was affected by two factors. The results of the statistical analysis demonstrated that the pollution in the region was of anthropogenic origin, and the activities related to the extraction and exploitation of the Abteymour oilfield, agricultural activities, and wastewater impacted the soil quality in the area. Investigation of the pollution level of the samples based on the Igeo, EF, Cf, and NIP indices indicated that the samples were unpolluted for most of the studied elements. Some samples had low pollution levels for elements Na, Mg, Cr, Ni, Sr, Cu, Li, and Pb. Sulfur (S) also included all pollution levels although most of the samples were at the medium level. Based on the modified contamination degree index (mCd) and ecological risk of the sum of elements (RI) indices, ۱۰۰% of the samples had very low levels and low risk, respectively. Due to the continuation of agricultural activities and oil industries in the studied area, there is a possibility of increasing the level of pollution.

کلیدواژه ها:

heavy metals ، Abteymour Oilfield ، Cluster analysis ، Factor analysis ، Geoaccumulation Index ، Enrichment Factor ، Contamination Factor