Accumulation and risk assessment of heavy metal contents in school playgrounds in Port Harcourt Metropolis, Rivers State, Nigeria

Abstract

Increase in anthropogenic activities has become threatening to environmental quality and public health. This study was carried out to determine the level of heavy metal contamination of school playground soils in Port Harcourt Metropolis. Soil samples were collected from ten (10) different school playgrounds and analyzed for their heavy metal concentrations using an atomic absorption spectrophotometer. The investigation revealed the concentration of heavy metals in this trend; Fe > Zn > Cr > Cu > Co > Pb > Ni > Mn > Cd > As > Hg. The models employed to evaluate the degree of contamination and source of metal pollution; index of geoaccumulation and pollution load, contamination and enrichment factors, and degree of contamination, showed that the sites were either categorized as unpolluted or with very low level of contamination that were within the background values. All the school playgrounds had moderate Mn contamination, while a few others had moderate Zn contamination levels. The result on the sources of deposition of these heavy metals varied from one metal to another and from one school to another. The result showed the deposition of Zn and Mn was purely of natural origin while Cu at all the schools, and Fe and Cr at most of the school playgrounds were deposited as a result of anthropogenic activities. The risk assessment study showed that the level of occurrence of these heavy metals on the school playground soils in Port Harcourt Metropolis, were all within safe levels. It is therefore imperative that regular assessment of these playgrounds be undertaken periodically to ensure the safety of these school children.