Open AccessAge-old transformation of oil hydrocarbons in polluted Grey-Brown Soil in the Absheron Peninsula
Author(s) -
Weiqiang Xiao,
Elena Bocharnikova,
Vladimir Matichenkov,
D. V. Demin
Publication year - 2021
Publication title -
iop conference series. earth and environmental science
Language(s) - English
Resource type - Journals
eISSN - 1755-1307
pISSN - 1755-1315
DOI - 10.1088/1755-1315/931/1/012006
Subject(s) - environmental chemistry , soil contamination , environmental science , pollution , contamination , pollutant , topsoil , environmental remediation , soil water , chemistry , soil science , ecology , organic chemistry , biology
Oil production, transportation and refining are a source of the extensive environmental pollution. The study of oil pollutants allows the identification of their behavior pattern necessary in order to elaborate efficient decontamination technologies. The Absheron oil field is one of the most long-term exploited deposit in the world. Today this area is a unique place to investigate the long-lasting natural oil transformation processes. Grey-Brown Soils contaminated with crude oil 100 and 40 years ago and currently were investigated. Hexane-extractable fraction of oil compounds was examined by chemical methods, gas chromatography and mass spectrometry. In the process of natural degradation, molecular weight of oil hydrocarbons and degree of oxidation significantly increased, while the contents of carbon and hydrogen slightly decreased with time. The results obtained have shown the accumulation of high-molecular weight aromatic molecules with high degree of unsaturation in the upper layer of the soil contaminated 100 years ago. These aromatic structures exhibit the great resistance to decomposition and may be carcinogenic, thus posing a risk to human health. The contamination with oil resulted in altering soil properties. More pronounced change was observed in the soil carbon, including the soil contaminated 100 years ago. Over time after contamination, the soil alkalinity enhanced, whereas soil pH did not change. Our study evidences that oil pollutants continue to be present and the soil properties have not recovered even 100 years after pollution. Reclamation of these areas requires the application of special technologies.