Evaluation of seasonal variation of heavy metal contamination and health risk assessment in Sabore field Adamawa State, Nigeria

Sabore field is characterised by a high level of artisan activities that contributes to water pollution by heavy metals; these heavy metals when present in drinking water can be deleterious to human health. Consequently, in 2018 we investigated the seasonal variations of the water samples from the Sabore vicinity to determine its suitability for drinking. Six metals (Mn, Cu, Cd, Zn, Ni, Pb) were studied, the health risk assessment was investigated using Hazard Index (HI), Hazard Quotient (HQ) and Cancer Risk (CR). The results showed that water from this locality have HI values > 1, Pb and Cd were top contributors to non-carcinogenic risk while Ni and Cd caused concern for carcinogenic health risk making it unsuitable for consumption. The seasonal spread of the metals shows that Mn varied from 148 to 976 mu g/L; Cu from 923 to 1676 mu g/L; Cd from 1.167 to 22.5 mu g/L; Zn from 63 to 118 mu g/L, Ni from 37 to 95 mu g/L and Pb from 128 to 185 mu g/L in the rainy season. For the dry season, Mn shows a spread of 1442-1802 mu g/L; 344-776 mu g/L for Cu; 57-82 mu g/L for Cd; 48-187 mu g/L for Zn; 147-242 mu g/L for Ni and 79-256 mu g/L for Pb. The increased concentration of some metals during the dry seasons could be attributed to the increased human activities around the field, increased evaporation rate, absence of rainfall and runoff water. The heavy metal content of water from some of the sites exceeded the stipulated permissible limits and poses serious health risk to its consumers.