Potential environmental and human health risk of soil and roadside dust in a rapidly growing urban settlement

The rate of urbanisation in Nsukka, Nigeria, is a trending phenomenon that is characterised by an overwhelming influence on the environment. Twenty-one dust and soil samples were collected from points strategically located on major roadsides in Nsukka and analysed for hazardous trace elements. The ecological and potential human health risks of the samples were estimated, and the pollution source was deduced with hierarchical cluster analysis. The relative abundance of the trace elements followed the order of Fe > As > Ni > Cr > Pb > Zn > Mn > Cu > Cd in roadside dust and Fe > As > Pb > Ni > Zn > Cr > Mn > Cu > Cd in roadside soil. Results obtained highlighted the impact of anthropogenic activities on soil and dust, as the multi-element contamination indices for the different groups of samples were below unity. The health risk assessment revealed that Cr was 120 times more likely to cause health problems than Pb and 450 times more than Ni. The agglomerated cancer risk (CR) for all exposure pathways estimated for children was about 1.2 times higher than that of adults, and the CR value for roadside dust was slightly higher than that of soil. All values of CR obtained were within the acceptable range of 10(-6) and 10(-4). Nevertheless, it is noteworthy to state that a significant health risk is bound to occur if adequate measures are not taken to curb the current rate of metal accumulation in the soil.