Fluoride is one of the most reactive non-metal compounds that are common in groundwater in Ghana. The most affected parts of Ghana are the Upper East, Upper West and Northern regions.
Studies indicate that the proportion of water sources (boreholes) with fluoride levels higher than 1.5mg/l (WHO/Ghana Standard Boards Permissible Limit) is in the range 20-30%. Because the element is reactive, it forms many complexes with several other elements and makes it difficult to remove using physical treatment methods. Fluoride is also one of few chemicals known to cause significant health effects through drinking water. High levels of fluoride compounds are available in igneous, sedimentary rocks and some metamorphic rocks.
Sources of Fluoride Ingestion into the Human body
Fluoride is known to enter the body through drinking water, food and air. Drinking water constitutes the most significant source of transmission into the body, whiles adsorption through the skin is common in industrial environments even though this may be in low concentrations.
Health Impact related to Fluoride Overloads
Fluoride is important for the protection of teeth and bones. The human teeth and bone is made up substantially of calcium. Low levels of fluoride provide protection for the teeth and prevent decay. Fluoride levels below 0.1mg/l have been associated with serious dental decay.
The World Health Organization (WHO) guideline level of maximum 1.5mg/l in drinking water is a guide to the daily intake of fluoride at which some mottling of teeth occurs, an indication of dental fluorosis. Overloads of fluoride in the body results in the formation of complex compounds with the calcium. The resultant compound is brittle, enhances decay and causes a condition called fluorosis.
In children, the fluoride attacks the developing tooth enamel and at higher levels causes severe discoloration and pitting. The more serious effects on bone structure-skeletal fluorosis arise as more fluoride is adsorbed. Risks of crippling exist when levels exceed 10mg/l.Elsewhere in other countries, increased incidence of bone fracture has been associated with drinking water levels of fluoride below 0.34mg/l and above 4.32mg/l (Bill McCann/IWA, 2007).
Current Actions to solve the Fluoride Threat
Advance knowledge exists for reduction of fluoride level in water treatment plants for large urban water supplies. For smaller supplies such as for small communities on point sources or households, significant success has been achieved but cost, taboos, culture and religious practices made some of the treatment methods for instance with carbon from bone sources unattractive and unsustainable in many developing countries. Various actions have been considered by the Community Water and Sanitation Agency towards finding acceptable and efficient methods for dealing with the threat that high fluoride burden places on the rural water sector in Ghana.