Polycyclic aromatic hydrocarbons (PAHs) concentration levels, pattern, source identification and soil toxicity assessment in urban traffic soil of Dhanbad, India

- Total PAH in traffic soil of Dhanbad varied from 1.019 μg g− 1 to 10.856 μg g− 1.
- Traffic sites were dominated by 4 & 5 ring while control sites by 3 ring PAHs.
- PCA study revealed vehicular emission as major source for PAH contamination.
- Carcinogenic potency of traffic soil was nearly 6.15 times higher than rural soil.

Present study was carried out to assess and understand potential health risk and to examine the impact of vehicular traffic on the contamination status of urban traffic soils in Dhanbad City with respect to polycyclic aromatic hydrocarbons (PAHs). Eight urban traffic sites and two control/rural site surface soils were analyzed and the contents of 13 priority PAHs was determined. Total PAH concentration at traffic sites ranged from 1.019 μg g− 1 to 10.856 μg g− 1 with an average value of 3.488 μg g− 1. At control/rural site, average concentration of total PAHs was found to be 0.640 μg g− 1. PAH pattern was dominated by four- and five-ring PAHs (contributing > 50% to the total PAHs) at all the eight traffic sites. On the other hand, rural soil showed a predominance of low molecular weight three-ring PAHs (contributing > 30% to the total PAHs). Indeno[123-cd]pyrene/benz[ghi]perylene (IP/BgP) ratio indicated that PAH load at the traffic sites is predominated by the gasoline-driven vehicles. The ratio of Ant/(Ant + Phe) varied from 0.03 to 0.44, averaging 0.10; Fla/(Fla + Pyr) from 0.39 to 0.954, averaging 0.52; BaA/(BaA + Chry) from 0.156 to 0.60, averaging 0.44; and IP/(IP + BgP) from 0.176 to 0.811, averaging 0.286. The results indicated that vehicular emission was the major source for PAHs contamination with moderate effect of coal combustion and biomass combustion. Carcinogenic potency of PAH load in traffic soil was nearly 6.15 times higher as compared to the control/rural soil.

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