ANALYSIS OF CHROMATOGRAMS FOR STUDY OF THE VADOSE ZONE AND SHALLOW AQUIFER CONTAMINATION BY PETROLEUM PRODUCTS

Contamination of shallow aquifers and rocks in the vadose zone with oil and its refined products is one of the most common types of technogenic pollution of the geological environment. Specifics of infrastructure development of territories require the compact location of enterprises engaged in the storage and transportation of petroleum products belonging to different business entities. When carrying out engineering and environmental survey, it is important not only to outline the contamination plume in plan and by geological cross-section, but also to identify correctly the sources of oil products entering the subsurface. To solve this problem, an approach was proposed based on comparing data on the chemical composition of oil products samples from prospecting boreholes. It is proposed to normalize chemical analysis data using a common and clearly distinguishable peak for all chromatograms. The approach was tested on the oil-polluted site. Comparison of chromatograms allows identifying the affiliation of petroleum products to different sources of pollution even if they are of the same type and have close average molecular weights. The results of the studies made it possible to prove the multiplicity of pollution sources (at least 4). The main directions of pollution transformation are the loss of light hydrocarbons and aromatic compounds as a result of their evaporation, dissolution in groundwater and biodegradation.