Hydrocarbon concentrations were determined according to the method described by Wypych and Mańko [34]. HS-SPME-GC/MS technique (Head-Space Solid Phase Microextraction-Gas Chromatography/Mass Spectrometry) was used. The analysis was carried out with Star 3400 Cx gas chromatograph; it was coupled to a Saturn 3 mass spectrometer and Autosampler 8200 Cx (Varian) with 10 ml autosampler vials. The chromatographic column with the phase DB624 and length 30 m x 0.32 mm ID (1.8 μm film thickness) was used. Helium was used as the carrier gas: purity 99.999%, flowing capacity of 1.0 ml/min (at 40°C). The gas chromatographic conditions were as follows: oven temperature was held at 40°C for 10 minutes, then increasing to 250°C by 10°C/min, and finally increasing by 5°C/min to 270°C. Total analysis time was 45 minutes. Injector temperature was 250°C.