Assessment of Drinking Water Quality Using Metal Index, Degree of Contamination and Hazard Indices on Ground Water Sources in an Agricultural Tropical Environment

Abstract

The study conducted in the dry and rainy seasons of 2019 assessed the levels of metals in groundwater sampled from boreholes and dug wells in Ikwo, southeastern Nigeria. Nine water samples were analysed for calcium, iron, zinc, copper, manganese and aluminium using Atomic Absorption Spectrophotometer (AAS). Analysis showed higher metal concentrations in the rainy season, except for manganese whose concentrations were higher in the dry season. The levels of the metals exceeded permissible limits in both seasons except for calcium. The metal indices were not greater than 2, while all degrees of contamination was less than 1. This collaborative classification of both metal index and degrees of contamination suggests that the water samples were safe to drink. The health risks assessed by Hazard Indices (HI) were classified into low and medium (≥ 0.1 to < 4) levels of chronic risks. The HI values were evaluated for both children and adults. The HI values were predominantly medium for children and low for adults. All indices for water quality evaluation agree that groundwater in the study area is of minimal contamination hence, no immediate threat to health. Therefore to ensure quality water supply, sustainable monitoring of water quality is recommended in the study area.