Iodine in drinking water from East African groundwater sources

Chronic deficiency has long been associated with development of iodine-deficiency disorders (IDDs). Drinking water, including groundwater, contributes to dietary iodine intake, and the prevalence of IDDs is widely reported. However, there are no minimum or maximum guideline concentrations for iodine in drinking water, and iodine is rarely analysed during traditional groundwater health studies. This study reviews the iodine content of drinking water sampled by the British Geological Survey, from groundwater sources in sixteen regions of Ethiopia, Uganda, Tanzania and Malawi. Preliminary results reveal that iodine concentration is associated with the amount of total dissolved solids, and shows the strongest relationship with sulphate, uranium, strontium, sodium and fluoride. Drinking water sourced from boreholes and hand dug wells are shown to have elevated iodine concentrations relative to local rainfall and spring sources. Work is ongoing to investigate the relationships between iodine and other solutes in the groundwater, and to build a database of groundwater in East Africa.