Assessment of pollution levels and risk of some heavy metals in soil and Mangifera indica around Nigeria Police Academy, Wudil, Kano State, Nigeria

Abstract

Elevated concentrations of heavy metals in the environment are potential ecological and human health risk. This study investigated the levels of Co, Cr, Pb and Zn in soil and plant (mangifera indica) and the risk of theses metals to plants and animal life in the area. Atomic Absorption Spectrophotometer (AAS) was used to analyse the metal contents of the samples, and the data subjected to statistical analysis, geo-accumulation index (Igeo), ecological risk index (Er) and health risk assessments. Except Co in site A and D, and Zn in site E, other soil metal concentrations are above the background values. All the soil samples fall within the uncontaminated to uncontaminated/moderately contaminated class (Igeo < 1), while the ecological risk results indicated that the studied sites contains metal with low risk to the environment (Er < 40) with the sites constituting low risk to the local ecosystem (RI < 110). The concentrations of Co and Zn in the plants are below the WHO permissible limit, while that of Cr and Pb exceeded the limit. There is no potential health risk from the metals, except from Pb in site C, which also accounted for 62.92 % of the total non-carcinogenic health risk. Only Cr indicated a life time probability of causing cancer. The current metal concentrations in soil and plants of the area does not pose serious threat to the population but should be properly monitored.