Evaluation of the Metal Content and Bacteriological Parameters of Selected Borehole Water Sources in Abakaliki, Nigeria

Abstract

The quality of potable water is affected by several natural and human activities including but not limited to pollution, natural disasters, climate change, urbanization and mining. Poor water quality adversely affects human health, and it is important to periodically be on the lookout for possible water contamination in our environment. This study investigated the metal content and bacteriological profiles of selected borehole water sources in Abakaliki, Nigeria. A total of 25 borehole water samples of 250 ml each were aseptically collected from selected borehole points (designated as Site A-E) in Abakaliki metropolis, Ebonyi State, Nigeria using pre-sterilized plastic containers; and each of the samples was were bacteriologically analyzed on selective culture media for the isolation and identification of bacteria that are of public health importance using standard microbiology identification techniques. The presence of trace metals was chemically determined in the borehole water samples using the atomic absorption spectrophotometer (AAS) [AA-7000]. The highest bacterial count in this study was 2.4 × 104 cfu/ml while the least bacteria count was 1.0 × 104 cfu/ml. The suspected bacterial organisms isolated and identified from the respective borehole water samples were Escherichia coli, Klebsiella species, Staphylococcus aureus and Pseudomonas aeruginosa. The metal content analysis using AAS showed that some of the borehole water samples contain some trace metals such as zinc (Zn), iron (Fe) and manganese (Mn). Aluminium (Al) and lead (Pb) were not detected in the borehole water samples analyzed in this study; and the trace metals detected were found to be within the accepted limit of trace metals for drinking water as specified by Standard Organization of Nigeria (SON) and World Health Organization (WHO). This study has presumptively reported the presence of some bacterial organisms of public health importance and some trace metals in selected borehole water samples in Abakaliki, Nigeria. The area under study is known for its high deposit of mineral resources especially lead and limestone; however, lead was not detected in the water sample and this shows that there was no infiltration of this metal from the mining site to the water sources in the region. Also, the proliferation of mining sites and their unregulated activities could also be responsible for the presence of some of these metals in the environment at concentrations that are unsafe for human use. Unsafe drinking water portends significant risk to public health over a lifetime of consumption. It is therefore important for the authorities to periodically screen water meant for human use and public consumption for the presence of potential physical, chemical and biologically contaminants that may affect the health of the populace.