Macek J. & Milička J., 2021: Light non-aqueous phase liquids distribution and weathering in former railyard; SE Danube Basin, Slovakia. Acta Geologica Slovaca, 13, 1, 1–12.

Light non-aqueous phase liquids distribution and weathering in former railyard; SE Danube Basin, Slovakia

Juraj Macek^1,2 & Ján Milička²

¹Centrum environmentálnych služieb, s.r.o., Kutlíkova 17, 852 50 Bratislava; macek@cenvis.sk
²Department of geochemistry, Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovičova 6, 842 15 Bratislava

Abstract

Petroleum hydrocarbons are one of the most common contaminants. Paper presents current theoretical approaches in identification and evaluation of sites with LNAPL (Light Non-Aquaeous Phase Liquids). To compare them with field results outputs from the ongoing remediation in a former railyard are utilized. New information from drilling and sampling is evaluated, with focus on the spatial distribution and migration of total petroleum hydrocarbons in soil and groundwater. Samples of LNAPL (diesel) were collected and analyzed by gas chromatography - mass spectrometry, to obtain more information about the quality, degree of weathering and the approximate age of the spill. It’s a common problem to distinguish between old and new contamination, and the observation of weathering rate can help to evaluate all possible contamination sources. Weathering degree of analyzed diesel samples ranged from almost none (even light n-alkanes abundant) to complete removal of all n-alkanes, though the railyard is more than 10 years out of operation. Based on the results, new LNAPL sources were identified, possible migration pathways were discussed and the age of LNAPL in different parts if the railyard was estimated.

Key words: SE Danube Basin, Quaternary, LNAPL, diesel fuel, contamination, weathering, distribution

Manuscript received: 2020-10-19

Revised version accepted: 2021-01-20