Heavy Metals Concentration in Road Dust in the Bolgatanga Municipality, Ghana

Abstract

The study was conducted to assess the level of contamination of surface dust from roads in the Bolgatanga Municipality. Dust samples were collected from the major Trans-ECOWAS roads and less busy road in the municipality and was determined using the Atomic Absorption Spectrometer at Atomic Energy Laboratory, Accra. The mathematical models; Index of Geoaccumulation (Igeo), Enrichment Factors (EF), Pollution Load Index, Contamination Factor and Degree of Contamination were employed to identify possible levels of pollution from human activities. The Index of geoaccumulation gave values in the range of unpolluted indicating insignificant accumulation of heavy metals from anthropogenic sources. The analysis of variance shows that chromium (Cr), mercury (Hg), cobalt (Co), cadmium (Cd) and zinc (Zn) concentration levels were highly significant in road dust collected from zone A, B, C and D. Some elemental pairs such as Fe/Cr (0.72), Ni/Co (0.64), Cd/Mn (0.81), Fe/Mn (0.70), Fe/Co (0.71), and Ni/Cd (0.81) have strong correlation at 5% significant level. The source of Cd/ Ni, Cd/Mn, Cd/Cr and Co/Cd in the road dust might be accumulated from wear-and-tear of tyres, combustion of fuel and oil/lubricants, which are known to contain trace levels of cadmium. There should be periodic monitoring by Environmental Protection Agency since heavy traffic condition can contribute to high levels of heavy metals in the road dust.