Spatial distribution, source attribution, and health risk assessment of groundwater trace metals in Gboko, Nigeria

ABSTRACT Diagram/Schematic: Figure 1: Schematic diagram of groundwater occurrence and movement in relation to the hydrological cycle Graph: Figure 2: A spatial map showing trace metal hot spots within the study area Chart: Figure 3: A chart showing the two types of CRI Picture: Figure 4: A picture used to depicts the levels of ecological and health risks Groundwater is a critical source of water for drinking and agriculture in Gboko, yet its quality is threatened by anthropogenic activities. However, spatially comprehensive data on metal contamination and its associated ecological risks remain limited. This study aimed to quantify the levels of heavy metals in groundwater and compute their ecological risks using a novel cumulative ecological index (CRI) to establish a baseline for environmental and public health protection. Fifty groundwater samples were collected across Gboko and analysed for physicochemical parameters and concentrations of key potential toxic metals. Concentrations of and exceeded WHO guidelines in some locations. Spatial maps revealed distinct contamination hotspots for the different trace metals arising from differences in the local geology and land use. PCA indicated both geogenic; weathering of ore mineral-rich quartz veins in rocks, and anthropogenic origins; applications of herbicides and fertilizers. CRI showed moderate to very high ecological risk in agricultural and industrial zones. Results of non-carcinogenic health risk revealed that and are the dominant metals that contributed to hazard quotient. There is insignificant carcinogenic health risk for children and adults in the area. The findings highlight groundwater degradation and provide data for prioritizing remediation and protecting public health.