By Samuel Godfrey
Many people living in the Rift Valley area of Ethiopia have stained teeth, as the result of drinking water that contains high level of fluoride. The yellowing of the teeth is one of the physical symptoms of consuming high levels of fluoride. Other symptoms include skeletal fluorosis, where children’s legs and arms are deformed resulting in physical disabilities. The World Health Organisation (WHO) recommends that drinking water should contain less than 1.5 milligram of fluoride per litre to ensure that teeth and bones are protected.
Fluoride gets into the water supply from the geological rock formations of the Ethiopian Rift Valley. Studies undertaken by the British Geological Survey have recorded levels of fluoride as high as 25 milligrams per litre in the area. These excess levels of fluoride are affecting more than 14 million women and children from Afar, Oromia and the Southern Nations Nationalities and Peoples Region (SNNPR), as well as parts of the Ethiopian Somali Region.
To solve the problem of excess fluoride, numerous water treatment technologies have been piloted by the Government of Ethiopia and International Agencies. These have resulted in varying levels of success. In the past, UNICEF has supported the mitigation of fluoride through de-fluoridation techniques in affected woredas, mainly in Oromia and SNNPR. UNICEF has also supported two studies, entitled ‘Study of fluoride and fluorosis in Ethiopia with recommendations on appropriate de-fluoridation technologies’ in 2005 and ‘Spatial distribution of fluoride in the Ethiopian Rift and its adjacent highlands’ in 2011.
With the financial support of the UK Department for International Development (DFID), UNICEF has developed a new approach that involves the ‘below ground’ treatment of fluoride. This approach is a permanent hydrogeological solution, which requires study of both the geological formations in which the fluoride occurs as well as the use of advanced remote sensing and groundwater drilling techniques.
Most deep wells that have been drilled in the Rift Valley have a maximum depth of 200 metres. This is due to both the occurrence of productive shallow aquifers (underground layers of water-bearing permeable rocks) and the limitations of available deep well drilling machines. UNICEF proposed to drill ‘deeper’ and to access aquifers that are 250, 300 or even 400 metres below ground level.
In April 2015 , UNICEF drilled a deep well in Welenchiti Town, a first for the Oromia region, to a depth of 259 metres and applied a phased casing technique to block off the shallow aquifers that are contaminated with fluoride. The result is a highly productive deep well with a yield of 11 litres per second – almost 40 thousand litres per hour (or 4 large water tankers per hour) – and a fluoride level of 0.9 milligrams per litre.
As a result of the planned intervention in Welenchiti Town and three surrounding villages, there will be approximately 45,870 beneficiaries by the year 2025. The project is expected to provide acceptable fluoride levels, with far greater health benefits than current supplies, which have resulted in chronic disease that affect all sections of the population, including children, with dental and skeletal fluorosis.