Spatial distribution and health risk implications of elemental hazard quotients in selected Nigerian cities

Abstract

The disease burden associated with air pollution is now comparable to that of other major global health threats, including poor nutrition and tobacco use. This study employed the gravitational settling method to collect airborne particles in selected Nigerian cities. The cities include; Benin, Kano, Abuja, Lagos, Enugu, and Calabar. Airborne particles were allowed to settle naturally into containers fitted with funnels and placed outdoors at various sub-locations within each State. Sampling was conducted over a nine-month period from January to September 2023. The collected sediments were analyzed spectroscopically using a UV Visible (UV-VIS) Spectrophotometer CE 1101 to determine concentrations of cadmium (Cd), nickel (Ni), lead (Pb), and manganese (Mn). Results revealed that hazard quotient (HQ) values for all analyzed metals exceeded the recommended safe limit of 1 across all locations. In Benin City, nickel and lead recorded HQ values of 5.5 and 4.0, respectively. Enugu showed particularly elevated levels, with manganese (Mn) at HQ 16 and lead (Pb) at HQ 5, attributed to industrialization and vehicular activities. In Kano, HQ values for lead (Pb) and nickel (Ni) were 8.0 and 4.9, respectively. Abuja recorded HQ values of 6.0 for lead (Pb) and 4.9 for nickel (Ni), likely linked to recycling and agricultural activities. Lagos and Calabar also exhibited elevated HQ values, particularly for lead and nickel. Elevated exposure to these toxic elements can pose potential health risks, including neurological, respiratory, and allergic effects, to exposed populations.