Evaluating the impact of traffic activities on the heavy metals concentrations along a major highway in Delta State, Nigeria

Abstract

Traffic emissions are one of the biggest drivers of heavy metals contamination in ecosystem; therefore vehicular traffic has become a major source of worry. The purpose of this study was to determine the influence of automobile emissions on roadside soil. Soil specimens were taken from two significant locations in Delta State, Nigeria, along a major highway.  Soil samples were collected at four different distances from the roadside (1 m, 10 m, 20 m, and 30 m) at each location. The amounts of heavy metals (copper, zinc, lead, and cadmium) in soil samples were determined using established techniques. The chemical analysis results revealed that heavy metal concentrations in roadside soil samples were substantially (p ≤0.05) higher than in the control soil sample. This revealed that the quantities of heavy metals in the soil samples were related to road traffic activity. The results also revealed that the amounts of heavy metals in roadside soil reduced as the distance between the test point and the highway increased. According to the findings, the copper, zinc, and lead contents in the soil samples were lower than the World Health Organization’s maximum tolerated values (WHO). However, the results revealed that the cadmium concentration was frequently higher than the WHO’s maximum tolerated limit. The findings also found that heavy metal pollution in roadside soils along the route ranged from minor to significant (degree). Furthermore, the concentration and pollution level at sampling position A were higher than those at sampling location B, which can be attributable to the fluctuation in the volume and concentration of traffic emissions received at each sampling point. To avoid the excessive accumulation of dangerous heavy metals in the ecosystem, our findings highlight the necessity to decongest vehicular traffic along major highways throughout the country.