Vehicle-Derived Heavy Metals and Human Health Risk Assessment of Exposure to Communities along Mubi-Yola Highway in Adamawa State (Nigeria)

Abstract

In this study, the health risk caused by heavy metals exposure to communities along Mubi-Yola highways was evaluated. Samples from Mubi, Hong, Gombi, Song, and Gerei were collected and analyzed for Lead (Pb), Cadmium (Cd), Chromium (Cr), Zinc (Zn), Cupper (Cu), and Nickel (Ni) using Atomic Absorption Spectrophotometer (AAS). The mean concentrations of the metals used for the risk assessment were observed to fall in this order Zn>Pb>Ni>Cu>Cd>Cr. The non-carcinogenic risk based on the target hazard quotient (THQ) and human health index (HI) values for each exposure pathway and for each metal were observed to be less than (<) 1 which means, exposure to the heavy metals has no immediate risks for both the adults and children in the settlements. The lifetime cancer risk (CRI) for the metals for both the ingestion (CRIIng) and inhalation (CRIInh) exposure pathways were observed to pose no lifetime carcinogenic risk. The CRI for all the exposure pathways and for all age categories were <10-4. Similarly, the combine effect or total cancer risk (TCRI) for each exposure pathway show high probability for carcinogenic risk by ingestion route compared to exposure by inhalation. The order of exposure were observed to be adults<children. Though the CRI and TCRI results were observed to be within the acceptable range for developing cancer, the result  however suggest that children could be more susceptible to potential carcinogenic risk following continual exposure to heavy metals from vehicular activity. Indicating some concern about the expansion of unregulated settlements along heavy traffic highways.