КАЧЕСТВЕННЫЙ И КОЛИЧЕСТВЕННЫЙ СОСТАВ УГЛЕВОДОРОДОВ ДОННЫХ ОТЛОЖЕНИЙ СЕВЕРО-ВОСТОЧНОЙ ЧАСТИ КАРСКОГО МОРЯ

Abstract

The surface layer (0–5 cm) of the bottom sediments, which samples were collected during the expedition of the RV “Academician Boris Petrov” in the Northeastern Kara Sea in the summer of 2022, has been investigated. Data on the content and composition of hydrocarbons (HCs) in the bottom sediments of the investigated aquatic area have been obtained. Since oil and petroleum products are among the most common sources of pollution of the seas and oceans, it is necessary to conduct regular surveys of marine ecosystems. This work is aimed at a qualitative and quantitative assessment of HCs in the bottom sediments of the Northeastern Kara Sea and identification of their possible sources. Examination of the qualitative and quantitative composition of HCs was carried out by gas chromatography using the gas chromatograph “Crystal-5000.2” with a flame ionization detector. The quantitative determination of the total HC content was conducted by the method of absolute calibration of the FID using a mixture of HCs prepared by the gravimetric method. Chromatec Analytic 3.0 software was used to process the results. It has been found that the total amount of HCs in the bottom sediments of the Northeastern Kara Sea ranged from 25.8 to 152.4 mg/kg, being 68.21±7.76 mg/kg on average. Based on analysis of the chromatograms, the predominance of high-molecular fractions has been identified; the maximum distribution of n-alkanes was represented by homologous compounds n-C25–C29, which are the markers of allochthonous organic matter. After comparison with the calculated diagnostic indices (CPI1, CPI2, ACL, LWH/HWH, TAR, C31/C29, Paq, TMD, ΣC25–35/ΣC15–21, Pr/Ph), it was found that the increased concentrations of HCs mainly result from the natural processes and prevalence of allochthonous organic matter in bottom sediments.