Concentrations, sources and exposure to metals in dusts from automobile mechanic workshops in Nigeria

dust is ubiquitous and humans are unavoidably in constant contact with it. Therefore exposure to metal laden dust from workplaces can be of serious threat to human health. The objective of this study was to assess the concentrations of nine metals such as Cd, Pb, Cr, Ni Cu, Co, Mn, Zn and Fe in dust from automobile mechanic workshops (AMWs) in urban and semi urban areas of Delta, Nigeria. The dust samples were digestion with aqua-regia and analyzed for metals by using atomic absorption spectrometry. The levels of metals in dust from the AMWs dusts (mg kg-1) ranged from 0.12 to 4.20 for Cd, 11.3 to 3897 for Pb, 9.05 to 45.3 for Cr, 0.35 to 345 for Ni, 170 to 56390 for Cu, 1.05 to 31.4 for Co, 51.3 to 310 for Mn, 143 to 634 for Zn and 70875 to 258013 for Fe. The indices for pollution assessment indicated that Cd, Cu, Pb and Zn were the prominent contaminants in dust from the AMWs. Children's exposure to metal laden dust from the AMWs could elicit adverse non-carcinogenic health effects. The carcinogenic risk values obtained for human exposure to metals in dust from the AMWs were above safe level indicating possibility of inducing cancer or cancer related sickness. The sources of metals in dust from the AMWs are related to automobiles emissions and discharges from vehicular components. The activities in the AMWs are potent source of metals to the environment especially Cd, Cu, Pb and Zn. Therefore, this study recommends regulatory control of the activities of the AMWs in order to minimize widespread of metal contamination and the impact of metals in the affected dust on humans and environment.