Health risk assessment of potentially toxic elements in dust and soils of used lead-acid battery shops, Nigeria

The poor quality of dust and soil in a polluted environment is a global concern because it affects human health and ecosystems. This study focuses on human activities related to the informal maintenance of used lead-acid battery (ULAB) shops in Nigeria. Forty (40) dust and soil samples were collected within and around informal automobile ULAB maintenance shops. The pH and electrical conductivity (EC) values of the dust and soils were mostly moderately to strongly acidic and highly conductive due to the indiscriminate spilling of sulfuric acid on the earth's surface. The most notable PTE is Pb, its average concentration in dust and soils are 17,415 and 17,937 mg/kg, respectively. These values are many folds higher than the other PTEs (Al, As, Cd, Co, Cr, Cu, Mn, Sb, V, and Sb), except Fe, which is generally abundant in the crust. The principal component analysis (PCA) identified that Pb, Sb, Cu, Cd, Zn, and As were sourced from anthropogenic origin from ULAB maintenance activities. However, Fe, Al, Mn, Cr, Co, and V were sourced from geogenic origin. The different contamination indices showed that Pb, Sb, Cu, As, Cd, and Zn consistently contaminate both dust and soils, while the geogenic PTEs showed low to moderate contamination. Only Pb and to some extent As had hazard quotient (HQ) for non-carcinogenic risk above permissible limit for both children and adults for ingestion and to some extent dermal contact. Also, the carcinogenic risk for only Pb was above the permissible limit.