Ecological risk estimation of heavy metal pollution in roadside dust of Ado-Odo Ota, Southwestern Nigeria

Abstract

Increased industrial, commercial and transport activities have constantly introduced air pollutants such as heavy metals in the atmosphere. Roadside dust samples were collected from 10 locations along Ota-Benin road, analysed for Cr, Cd, Co, Ni, Pb, Fe, Mn, Cu, As and Zn, and the ecological risk was evaluated for the heavy metals' concentration in the roadside dust particles using the Hakanson method. The results revealed that Cd (3.103 mg/kg) and Cu (mg/kg) surpassed the threshold effect level. Pollutant source identification analysis revealed possible origin from motor oil, plastics, metalliferous extraction, dyes, and paints industries. The contamination factor for Ni was found to be at a moderate level in location SM8, SM9 and SM10 and a similar category was observed for Pb in location SM7, SM8, SM9 and SM10. Zn concentration in location SM5, SM6, SM7, SM8, SM9 and SM10 fell within the moderate contamination factor zone as well. Furthermore, the mean E ir of the individual metals in the sample region followed the order of Cd > Ni > Pb > As > Cu > Zn > Cr indicating a high risk associated with cadmium within the sample region.