Study of Correlation Between Heavy Metal Concentration, Street Dust and Level of Traffic in Major Roads of Kano Metropolis, Nigeria

Abstract

This study was aimed at evaluating heavy metal contents in street dust of five major roads within the trunk of Kano metropolis. The dust were collected from heavy traffic roads of the city which include Zaria road (ZR), Maiduguri road (MR), Katsina road (KR), Hadejia road (HR) and Bayero University Kano road (BR). Triplicates samples were collected and the number of vehicles that pass through each road was recorded for one hour. The metal concentration of the dust was determined using atomic absorption spectroscopy (AAS). Strong positive correlation exist between the amount of dust collected and the number of vehicles that passed in all the roads except for Hadejia road with r² = 0.32 which is less positive. The metal contents in dust of the five streets were higher than the WHO reference value. The positive correlation between the number of vehicles and metal type was significant (P<0.05) for Zn, Fe, and Mg in ZR, Pb and Fe in HR; Fe and Mn in BR, while between street dust and metal type was significant (p<0.05) for Zn and Fe in ZR; Fe and Cu in KR; Ca in HR and Fe in BR. The high positive correlation observed in this study may mean that the metals in the street dust originate from common anthropogenic sources. Higher than reference values of the heavy metals in street dust, indicate hazard associated with residing or conducting business along the major street in the city. The finding is in support of government effort in protecting its citizenries by prohibiting road site business.