Risks Assessment of Heavy Metal Pollution in Roadside Soil and Vegetation of National Highway Crossing through Industrial Area

A descriptive research was conducted seasonally for divulging the impact of deposition and contamination of selected heavy metals (HMs) like Cd, Ni, Cu, Pb, Zn and Cr) in roadside soil (RSS) and grass (Cynodon dactylon) of a National Highway (Dhanbad - Raniganj; NH 2, India). The contamination factor for Cd was found maximum among all the HMs during pre-monsoon season and the highest geo-accumulation index was also found for Cd. The ecological risk index (ERI) was calculated and compared with two control sites which showed elevated risk of HMs in the RSS. The highest ERI value (596) was observed in the pre-monsoon. The general trends of bio-concentration factor, bio-accumulation factor, and translocation factor were Zn > Ni > Cr > Cu > Pb > Cd, Zn > Ni > Cu > Cr > Pb > Cd, and Ni > Zn > Pb > Cr > Cu > Cd, respectively. Potential health risk (non-cancer) for children and adults was also assessed, and the highest hazard indices in pre-monsoon were found for children (4.80 x 10(-1)) and adults (6.33 x 10(-2)). The total cancer risk in pre-monsoon for adults was 0.324 x 10(-4)while for children was 0.295 x 10(-4). This study demonstrates the occurrence of HMs in the road side soil causing the increase in the health risks problems for the nearby residents. The findings of the present study can be further interpreted to assess the health risk posed due to the exposure of HMs near RSS of the highways covering the industrial areas elsewhere in the world.