Application of alkane biological markers in the assessment of the origin of oil pollutants in the soil and recent river sediments (River Vrbas, Bosnia and Herzegovina)

In this paper, an attempt was made to contribute to the use of biological markers, n-alkanes, and polycyclic alkanes of the sterane and terpane type, in the assessment of the source of oil pollutants in the environment using the example of the correlation between recent river and coastal sediments,. Four samples of recent river sediments of the Vrbas River and four samples of adjacent bank sediments (soils), in the part of the River that belongs to the city of Banja Luka (Bosnia and Herzegovina) were analyzed. In the alkane fractions of isolated extracts, a bimodal distribution of the n-alkanes was observed. Lower homologues dominated in the recent river sediments with maximum at C15, but higher n-alkanes dominated in the soil samples, with a maximum at n-C29 or at n-C31. The higher concentration of steranes and terpanes with oil type distributions in the recent/fresh river sediments (compared to the bank sediments) represents evidence that lower n-alkanes originate from oil sources. The higher content of total hydrocarbons in the recent river sediments than in the bank sediments further confirms this conclusion. At the same time, these fundamental considerations provide evidence that oil pollution primarily occurred in the water flow and then the oil pollutants propagated towards the riverbank.