Total petroleum hydrocarbons distribution and health risk assessment of soil in the Niš railway junction

Abstract

A particularly high pollution level of total petroleum hydrocarbons (TPH) was observed in the soil at the railway junction in the city of Niš (Serbia). The TPH level in most of the studied soil samples exceeded the limit intervention value of 5000 mg/kg. The contamination level decreased alongside the train rail route, according to the distance from the fuel station. This suggests the pollutant role of railway transport, with the fuel station identified as a pollution hotspot. Health risk assessment of the contaminated soil has been made by using TPH fraction approach. Among six aliphatic and seven aromatic hydrocarbon fractions, the highest TPH content in soil was measured for EC16-C35 aliphatic fraction. This aliphatic fraction causes the highest individual non-cancerogenic health risk, while cancerogenic risk is mostly attributed to EC16-21 aromatic fraction. Both the total non-cancerogenic risk (expressed as a hazard quotient) of 5.8, and cancerogenic risk (expressed as an incremental excess lifetime cancer risk) of 11.7·104, notably exceed safety target values of 1.0 and 1.0·10-6, respectively.

Značajno visok nivo zagađenja zemljišta ukupnim naftnim ugljovodonicima (TPH) detektovan je na lokaciji železničkog čvora u gradu Nišu (Republika Srbija). Koncentracije TPH u većini ispitivanih uzoraka zemljišta premašuju remedijacionu vrednost od 5000 mg/kg. Nivo kontaminacije se smanjuje duž trase železničkih šina, shodno udaljenosti od benzinske pumpe. Dobijeni rezultati sugerišu značajnuulogu železničkog transporta u zagađenju, a benzinska pumpa je identifikovana kao žarište zagađenja. Procena zdravstvenog rizika od zagađenog zemljišta je urađena primenom TPH frakcionog pristupa. Među šest alifatičnih i sedam aromatičnih frakcija ugljovodonika, najveći sadržaj TPH u zemljištu izmeren je za alifatičnu frakciju EC16-C35. Ova frakcija uzrokuje najveći pojedinačni nekancerogeni zdravstveni rizik, dok se kancerogeni rizik uglavnom pripisuje aromatičnoj EC16-21 frakciji. Ukupni nekancerogeni rizik (izražen kao količnik opasnosti) od 5,8 i kancerogeni rizik (izražen kao inkrementalni višak rizika od kancera u celokupnom životnom veku) od 11,7·104, znatno premašuju ciljne bezbedne vrednosti od 1,0, odnosno 1.0·10-6.