Geostatistical mapping of soil characteristics to uncover geographic patterns of CKDu in dry zone, Sri Lanka

Addressing contemporary and future public health challenges necessitates a comprehensive understanding of the role of soils, particularly in relation to the rising incidence of Chronic Kidney Disease of Unknown etiology (CKDu) in Sri Lanka. This study investigates the spatial distribution patterns of nephrotoxic heavy metals in soils within CKDu-endemic regions, employing spatial interpolation and spatial autocorrelation analyses to inform evidence-based policy development for disease prevention. The concentration hierarchy of heavy metals in soils from CKDu-affected areas was observed as Zn > Cu > Pb > As > Cr > Cd. Notably, the levels of Cd, Pb, and Cr were significantly elevated in hotspot regions compared to reference (non-endemic) sites. Spatial analysis using Global Moran’s Index (MI) revealed a clustered distribution of cadmium (MI = 0.3145), particularly in areas under paddy cultivation, suggesting a strong association between agricultural practices and cadmium accumulation. In contrast, Pb, As, and Cr exhibited more randomized spatial distributions at comparatively lower concentrations. These findings underscore the critical concern of heavy metal accumulation—especially cadmium—in agricultural soils and its potential entry into the human food chain via rice cultivation. The implications for public health are profound, highlighting the need for targeted soil management and agricultural interventions as part of a sustainable strategy to mitigate CKDu prevalence in Sri Lanka.