Determination of Heavy Metals and Human Health Risk Assessment of Road Dust on the Tema Motorway and Tetteh Quarshie Interchange in Accra, Ghana

Abstract

Street dust samples were collected from Tema Motorway (near Ashiaman overhead) and Tetteh Quarshie interchange in Accra. The samples were segregated into two groups of grain sizes be-tween 100 um - 250 um and the other being less than 100 um. Energy dispersive X-ray flores-cence technique was used to determine their elemental compositions. In all twenty (20) elements were identified: K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, Ge, As, Se, Br, Rb, Sr, Y, Zr and Pb. The results show significant concentrations levels of K, Ca, Ti Pb, Zn, Cu, Mn, Fe, Rb, Sr, Y, Zr and Cr in all the samples. Enrichment factors determined for the elements show high enrich-ment of V, Zn, Cu, Zr, Cr, Br and Pb from the sample sites. There was no indication of signifi-cant anthropogenic contribution of manganese (Mn) which gave average enrichment factor val-ues of 0.60 and 0.78 in the road dust at the Tema motorway and Tetteh Quarshie Interchange respectively. Risk assessment of selected heavy metal contaminants from both sites indicate that Pb gave Hazard Index (HI) values of 0.56 and 0.62 which falls below the safe level of one (1). It was also observed that ingestion which gave HI values of 2.1 and 2.3 was the highest risk of ex-posure pathway. Tetteh Quarshie Interchange gave the highest cumulative risk of exposure.