Heavy metal pollution and health risk assessment of road dust on selected highways in Düzce, Turkey

In this study, road dust samples from state roads D-100 and D-655 passing through the city of Duzce, Turkey were analyzed using ICP-MS to ascertain heavy metal pollution, and also to evaluate possible risks to human health. Some pollution indices such as enrichment factors (EFs), geo-accumulation index (I-geo) and integrated pollution index (IPI) were calculated to determine the pollution levels of metals. According to the mean EF values, Zn, Mo, and Pb exhibited significant enrichment, while enrichment of As, Cd, Sn, and Sb was very high. The I-geo values for Pb, Ba, Mo, Zn, Cu, Mn, and Cr indicated an extremely polluted environment whereas those for Sc, V, Fe, As, Cd, Sn, and Sb indicated moderate to strong pollution of the environment. The IPI values of Pb and Mo were also at extreme levels due to vehicle traffic related contamination along the roads. Analysis of the road dust matrix indicated the mixed effect of the fossil fuel combustion for residential heating and industrial activities within the studied area as well as traffic originated pollution. Cluster analysis revealed that sampling area has been influenced by mainly three pollution sources: (i) traffic and industrial activities, (ii) polluted soil due to accumulation, and (iii) fossil fuel combustion. According to human health risk assessment studies, a level lower than 1.0 has been determined to be a non-cancer health risk. However, a total hazard index level of 1.4 poses a significant non-cancer health risk for children. Fortunately, a total lifetime cancer risk value of 8.8x10(-8) was found, and this is considered safe.