Pollution Assessment of Two Urban Soils in the City of Ngaoundere, Cameroon

Abstract

Urban soils contain high concentrations of both inorganic and organic pollutants due to anthropogenic activities that compromise their physicochemical quality. The aim of the present study is to assess the contamination level of the soils around the central prison and the regional hospital of Ngaoundere (Cameroon) exploited for crop production. To achieve this objective, soil samples were collected from the surface at a depth of 0-20 cm and 20-30 cm and were analysed to determine heavy metals level on one hand and the enrichment factor (EF) and the geo-accumulation index (IGEO) on the other hand to better assess the level of contamination. Results showed that the concentrations of heavy metals in soils varied according to sites and ranged from 0.51±0.01 to 4.93±0.07 mg/kg for Cd, 10.57±0.01 to 99.47±0.80 mg/kg for Cu, 595.57±0.60 to 872.85±1.58 for Fe, 24.35±0.56 to 43.62±0.65 mg/kg for Ni, 35,25±0.26 to 307.21±0.32 mg/kg for Pb and 31.73±0.11 to 384.32±5.84 mg/kg for Zn. The sequence of heavy metal concentrations in the hospital and prison soils was as follows: Fe>Zn>Pb>Cu>Ni>Cd. Base on the IGEO and the EF the results showed, apart from iron, an accumulation of various metals in both prison and hospital soils. These soils are not suitable for crop production because there is a risk of contamination of the human food chain.