Re-evaluation of Vehicular Heavy Metal Deposits on Roadside Soil in Eket, Akwa Ibom State, Nigeria

Abstract

This study assessed the level of contamination of selected heavy metals (HMs), including Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn at four designated sampling locations: SP1, SP2, SP3 and SP4 in Eket, a city in Akwa Ibom State of Nigeria. Roadside soil specimens were gathered from these sites to form a composite sample. Standard method was used to analyze each soil sample, while the contamination levels of individual and combined HMs in soils were assessed by contamination factor (CF), geo-accumulation index (Igeo), degree of contamination index (CDI), and pollution load index (PLI). The results revealed that all the HMs, except Cd, did not pose any environmental risk at all the sites, as CF and Igeo values for these metals were less than one respectively. However, Cd showed varying degrees of contamination across the sites, with a moderate environmental risk at SP2 and SP4, and a very strong environmental risk at SP1 and SP3. The combined effect of the HMs, as assessed by the CDI and PLI, showed differences, while CF and Igeo values for individual HMs were similar. The overall contamination at the sites, based on CDI, ranked as SP3. The results suggest possible health risks for the populace in these vicinities due to Cd exposure and recommend further investigation into the health risks associated with Cd in the region.