Heavy Metals Pollution in Ambient Air and Health Risk Assessment in Eket, Akwa Ibom State, Nigeria

Aims: Air pollution is an enormous problem due to its detrimental health effects on exposed populations. The present study assessed the level of heavy metals in ambient air and related health risk based on ingestion, inhalation, and dermal routes of exposure to heavy metals. Place and Duration of Study: Sampling was performed at three selected junctions namely: Mobile matt (MM), Uqua junction (UJ), and Marina junction (MJ) using pre-weighed Petri dishes for 15 minutes at 1.5 m above ground surface. Methodology: Heavy metal concentrations such as cadmium (Cd), Lead (Pb), manganese (Mn), arsenic (As), nickel (Ni), Copper (Cu) and chromium (Cr) were investigated using standard methods. The non-carcinogenic and carcinogenic health risks were assessed using exposure concentration (EC), hazard quotient (HQ), and hazard index (HI), and additional lifetime cancer cases. Results: Metal concentrations at MM, UJ, and MJ vary from 63 to 165 (mg/m3) for Cd, 314 to 823 (mg/m3) for Cr, 3 to 28 (mg/m3) for Pb, 284 to 412 (mg/m3) for Mn, 1 (mg/m3) for As, 73 to 202 (mg/m3) for Ni and 1 to 3 (mg/m3) for Cu, respectively, over a 15-minute average. All of the observed heavy metals' mean concentrations - Cr, Cd, Cu, Pb, Mn, As, and Ni are higher than the ATSDR reference concentration for inhalation. HI for children at MJ indicated the possibility of non-CRs through ingesting. The probability of non-CRs by inhalation and skin exposure was demonstrated by HI for adults and children at MM, UJ, and MJ. While the ILCR values for Cd and Ni revealed moderate carcinogenic hazards from ingestion and inhalation of these metals at MM, UJ, and MJ, the ILCRing and ILCRinh values for Cr indicated substantial CRs from this metal. ILCRder values for Cr and Ni indicate low CRs for dermal routes. Conclusion: Continuous monitoring of metals and health risk assessment is recommended in the study area.