Study on rare earth elements, heavy metals and organic contents in the soil of oil exploration site at Matruh Governorate, Egypt

Abstract

Soil is an issue material for sustainable economic and development plans; besides it considers the most valuable natural resource in all fields of citizens' life. This study is carried out to assess the impacts of heavy metals and some organic constituents on the soil, and consequently on its pollution, in a sampling point left behind the exploration activities in a site subjected to oil and gas exploration nearby Matruh Governorate, Egypt. Moreover, it is trying to evaluate the contents of some added-value rare earth in the same area. Samples were collected from ten points in a bore at different depths starting at 13,000 feet with increasing down distance every 50 feet. The study area is located within latitude 30° 48′ to 36° 889 ̋ S and longitudes 26° 59′ to 16° 406 ̋ E. Geographically, Matruh is part of the Great Western Desert.

Rare Earth Elements (REEs), Heavy Metals (HMs) and organic constituents in the soil samples were analyzed based on Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) and Fourier transform infrared spectroscopy (FT-IR). Geoaccumulation Index (Igeo), Enrichment factor (EF) and Pearson Correlation Coefficients (R) were calculated to consider the soil pollution in the studied point. Also, to evaluate the abundance of REEs and to follow the relations between those elements.

The study illustrated that: the most organic soil pollutants in the oil field sewage were aliphatic and aromatic hydrocarbon, phenols, organic sulfide aliphatic acid and others. Based on the geoaccumulation Index (Igeo) and Enrichment Factor (EF) classifications, the soil quality of the studied site can be classified, in general, as class 0, (uncontaminated) to class 6, (extremely contaminated). Moreover, The potentiality of the rare earth should be subjected to intensive studies to decide their economical mining and element processing.