Spatial dynamics of borehole water quality across functional zones: a comparative study of military and civilian settings in Makurdi, Nigeria

Abstract

We aimed to assess the physico-chemical properties and heavy metal concentrations of borehole water across five functional areas within three restricted military formations and compare them with those of nearby civilian control sites in Makurdi, Nigeria. In total, 18 composite boreholes were sampled. The measured parameters included pH, electrical conductivity, total dissolved solids, dissolved oxygen, biochemical oxygen demand, hardness, major cations (K⁺, Mg²⁺ and Na⁺) and heavy metals (As, Cd, Pb and Hg). Compared to the control sites, Military Formation A exhibited significantly higher biochemical oxygen demand and turbidity, particularly in the Workshop and Residential areas, with the first principle component demonstrating strong synergy between domestic effluent and metal loadings. Military Formation C exhibited the highest levels of mineralisation (electrical conductivity, total dissolved solids and hardness), particularly in the Residential and Office areas, while Military Formation B maintained superior water quality, characterised by high dissolved oxygen and an alkaline pH, particularly in the Mammy Market and Office areas. Borehole water in the military installations was generally superior to adjacent civilian sites owing to controlled land use. However, localised hotspots in School and Workshop areas remain vulnerable to organic loading and geogenic As mobilisation, necessitating zone-specific remediation.