Hydrogeochemical processes in groundwaters of Uganda: a national - scale analysis

Abstract Groundwater represents a vital source of freshwater to meet distributed, rapidly rising demands for safe drinking water, irrigation and industry in low-income countries across the tropics. The hydrochemistry of groundwater within deeply weathered crystalline rock aquifer systems that predominate at low latitudes, is determined primarily by long-term biogeochemical weathering of the parent bedrock. Here, we evaluate geochemical footprints and baseline chemical quality of groundwater that have developed from water-rock interactions across a range of geological environments in Uganda using a national database of hydrochemical and hydrogeological records from 3271 locations. Sampled groundwaters are mostly shallow (69% of samples from depths of