Contamination, ecological and health risk assessments of potentially toxic elements in soil around a municipal solid waste disposal facility in Southwestern Nigeria

Abstract

BackgroundThe increasing level of waste generated and disposed of especially in urban centers arising from population explosion and rapid industrialization is a global concern, because it may lead to the pollution of potentially toxic element (PTE) in surrounding soils and groundwater. This research is aimed at the investigation of PTE contamination in soil around a municipal solid waste open dump facility and their human health risk in Ibadan, Southwestern Nigeria. MethodsForty (40) soil samples were collected at 20 cm depth within the facility (WFC), close to the facility (CFC), and far from the facility (FFC). The soil samples were analysed for Cd, Co, Cu, Mn, Ni, Pb, and Zn using atomic absorption spectrometry technique. ResultsOn the basis of the mean concentration, PTEs decrease in the following order Zn > Mn > Pb > Cu > Co > Ni > Cd. The contamination statuses of Cd, Cu, Pb and Zn were high-very high at WFC, moderate-high at CFC, and low-moderate at FFC. The principal component (PC) analysis showed three loadings; PC1 composed of Cd, Cu, Pb, and Zn that were attributed to anthropogenic input from the materials dumped within facility while PC2 (Co and Ni) and PC3 (Mn) were sourced from the geogenic origin from weathering of rocks and soils. Only the ecological risk potential (Er) of Cd and Pb was high at WFC, considerable at CFC and low at FFC and affect the overall ecological risk (RI) of WFC and CFC. The hazard quotient and hazard index of non-carcinogenic risk were only > 1 for Cd especially for children at WFC and therefore, may pose health risk in the vicinity of the facility. The carcinogenic risk (CR) is within permissible limit. ConclusionThe anthropogenic activities in the municipal solid waste facility have impacted the soil of the area by some PTEs and posed potential human health risk to the people living close to the site. Therefore, constant monitoring of the area by regulatory bodies is recommended to reduce the impact of the PTEs on the soil.