Elemental Profiling, Pollution and Health Risks Assessments of Classroom Dust from Selected Nursery and Kindergarten Schools Ogun State, Nigeria

Abstract

Knowing the concentration of elements in children’s classroom dust and the associated ecological and health risks is essential in preventing and controlling possible elemental poisoning. Dust samples were collected from 37 nursery and kindergarten classrooms across three local government areas in Abeokuta, Nigeria, and assessed for elemental concentrations using X-ray fluorescence (XRF) spectrophotometry. The hazard and the cancer risk indexes were estimated using the geo-accumulation index (I_geo) and health risks posed to children. The highest mean concentrations (mg/kg) of Ca, Fe, K, and Ti ranged between 4034.22–15995.09, 1758.95–2409.62, 5146.66–8996.75, and 730.96–1140.38, respectively. About 33.33% of the monitored metals displayed I_geo values within the moderately polluted and extremely polluted categories in Abeokuta South and North. All the monitored locations were strongly polluted with Ca, Fe, K and Ti, including arsenic at Abeokuta South. Metals with high pollution (C_f > 6) were Ca, Fe, Co, As, K, Ti and Ge in Abeokuta South. Ca, Fe, Co, As, K, Sc, Ti and Ge in Abeokuta North; and Ca, Fe, As, K, Sc, Ti and Ge at Odeda. Arsenic levels were 128.42 (considerable), 2934.27 (very high) and 179.33 (high) for the ecological risk factors. Dust samples for Abeokuta South and North posed the least and greatest ecological risks, respectively, and the risk potentials of arsenic across all the locations were in the ecologically risky ranges. However, hazard indexes < 1 were recorded across the monitored sites, indicating no immediate non-carcinogenic health risks, while cancer risks for Co, Ni, As, and Cr were < 1.0E−04, respectively, depicting no significant carcinogenic risk. This study concluded that the levels of elements monitored do not pose any health risk to the children but are of concern to the ecosystem. Therefore, policies on locating schools in areas with minimum anthropogenic pollution should be formulated and continuous cleaning of classroom surfaces should be encouraged.