Biogeochemical assessment and health implications of borehole groundwater system using principal component analysis in Itori community South-West Nigeria

Abstract

The significance of quality water consumption for the overall health and wellness of any population cannot be overemphasized. The water quality status of boreholes and hand-dug wells in Itori community of Ewekoro Local Government Area, South-West Nigeria was examined in this study. Inhabitants of this region depend solely on these water sources for consumption and other comforting purposes. Water samples were collected from 25 boreholes at various sampled points across the study area. Standard analytical water quality methods using Inductively Coupled Optical Emission Spectrometry (ICP-OES) were employed in the laboratory (Geochemical and bacteriological analyses) for 25 borehole water samples collected in the study area and the corresponding results were compared with both National and International water quality standards. Most quality determinants in the sampled water are within WHO guidelines except BOD, ALK, Cl-, NH4+, HCO32-, MgCO3-, Zn2+ and Fe3+. The overall ionic dominance pattern follow the same trend K+ >Na2+ > Fe3+ >Mn2+ and Cl- >NO3- >NO2-. The hygienic status of the water sources is found to be poor. High BOD5, Coliform Count and BOD5:NO3- ratios of groundwater samples are indicative of organic pollution due to faecal contamination with the lowest measured depth of 35m and highest measured depth of 85m. Multivariate statistical approach namely Correlation, Principal Component Analysis and Bubble Plot was used to identify interrelationships among the analyzed physicochemical parameters and the pollution sources. PCA reveals maximum 6 PCs; with the sources of pollution emanating either from natural hydrogeochemical or anthropogenic processes, or a combination of both. The results therefore imply that boreholes in Itori are polluted and pose potential risk to biomedical safety and overall human health. Intervention measures from Government and Non-governmental Organization including public awareness campaigns in Itori and entire Ewekoro local Government Area is necessary to safeguard the inhabitants from water-related diseases and their consequences.