The study of organic impurities composition in natural waters, particularly CO₂-rich mineral waters, is an important aspect of geochemical research. It provides an understanding of transformation mechanisms and migration of organic matter and also allows researchers to identify organic pollutants and their distribution pathways. The study objects include mineral waters with high concentrations of mantle CO₂, as well as surrounding groundwaters and surface waters. The solid-phase extraction method was used in situ to concentrate semi-volatile organic compounds. Qualitative analysis of these compounds was carried out using capillary gas chromatography-mass spectrometry. Dissolved organic carbon (DOC) was identified using a high-temperature catalytic oxidation method. The DOC concentration ranged from 0.5 mg/L in the groundwaters to 9.1 mg/L in the river waters. A total of 133 semi-volatile organic compounds were identified in the studied waters. The saturated, branched and aromatic hydrocarbons dominated in the deep CO₂-rich mineral waters. Similar components were also predominant in the shallow mineral and fresh waters, together with terpenes and phthalates. It was established that the relative concentration of n-alkanes, alkenes and arenes is higher in the mineral waters than in the fresh waters. In contrast, the relative content of isoalkanes, heteroaromatic hydrocarbons, esters, alcohols and terpenes is higher in the fresh waters than in the mineral well. The mineral waters contained range of arenes and naphthenes that were absent from the fresh waters. Conversely, the fresh waters contained a greater variety of isoalkanes, esters, heteroaromatic hydrocarbons and terpenes than mineral waters. The possible origin of organic matter was attributed to bacterial activity and interaction with sedimentary deposits, whereas the influence of plant residues appeared to be less significant. In our opinion, the mantle CO₂ may extract naphthenes and arenes from sediments in the deep mineral waters. In addition, phthalates, Cl-hydrocarbons and several other compounds were detected in the studied waters and were interpreted as anthropogenic pollutants. Therefore, the studied waters appear to be susceptible to anthropogenic contamination.