Assessment of the groundwater quality of a highly populated district in Enugu State of Nigeria

This study assessed the water quality of the hand-dug well groundwater of Independence Layout, a highly populated district of Enugu Metropolis in Enugu State of Nigeria by sampling 14 hand-dug wells during the rainy and dry seasons. Samples were collected in such a manner as to ensure that each of the seven zones that make up the district had two wells sampled. The water quality was assessed based on the biological and physico-chemical properties of the groundwater. Atomic absorption spectrometry was employed in the laboratory analysis of the heavy metals. The physico-chemical parameters were determined following standard procedure. Obtained results indicate that the measured parameters were below the water quality standard values of Standard Organization of Nigeria except for lead during the dry season for three wells. Water quality assessment was premised on ranking using water quality index which indicated that all the wells were either of good or excellent quality during the rainy season (with water quality index ranging from 26 to 63) but poor during the dry season (with water quality index ranging from 101 to 106) in three wells. Risk assessment was carried out using hazard index (HI) which revealed insignificant non-carcinogenic health risks as HI values for all the wells were far less than unity (ranging from 0.03 to 0.17). The microbiology of the water indicated the presence of non-pathogenic organisms such as Bacillus subtils in three wells and pathogenic organisms such as E. coli, Serratia spp., Proteus mirbilis and Salmonella spp. in the rest of the wells. The presence of either pathogenic or non-pathogenic organisms in the groundwater of Independence Layout signals that the water of the study area should be treated before use.