ORGANIC MATTER (PAHs and n-ALKANES) IN NATURAL WATERS OF KUZBASS: TRACKING NATURAL AND ANTHROPOGENIC SOURCES USING HYDROCARBON GEOCHEMISTRY
E.V. Domrocheva, I.S. Korol, N.A. Mukhortina
1Tomsk Branch of the Trofimuk Institute of Petroleum Geology and Geophysics of Siberian Branch Russian Academy of Sciences,Tomsk, Russia
Keywords: Natural waters, polycyclic aromatic hydrocarbons (PAHs), n-alkanes, source apportionment, dissolved organic matter (DOM), coal-bearing basins, Kuzbass.
Abstract
Using the example of the Kuznetsk Basin – one of the largest coal-mining regions in the world – a comprehensive analysis has been performed of the composition of dissolved organic matter (DOM) in groundwater of various hydrodynamic zones and of their interrelation with surface waters. With the use of modern analytical methods, namely high-performance liquid chromatography for polycyclic aromatic hydrocarbons and gas chromatography–mass spectrometry for n-alkanes, the concentrations and ratios of polycyclic aromatic hydrocarbons (PAHs) and n-alkanes have been determined. The PAHs are predominantly of pyrogenic origin (coal and fuel combustion), but in groundwater their initial composition is significantly transformed. The distribution of n-alkanes and the calculated indices (CPI, TAR, Paq) reflect a change in sources: from phytoplanktonic in surface waters to terrigenous (higher plants, macrophytes) in the deep horizons of the slow water‑exchange zone. A correlation has been revealed between water mineralization and the ratio of low‑ to high‑molecular‑weight PAHs, which indicates the influence of ionic strength and sorption processes in the water–rock system. The molecular composition of DOM is a sensitive indicator of pollution sources and of the transformation processes of organic matter in anthropogenically disturbed coal‑bearing territories. The results are significant for environmental monitoring and for prediction of the state of aquatic ecosystems.
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