L. PARWANI AND MD. A. RAHMAN
Abstract
All forms of life essentially require water for the maintenance and surveillance of life on earth. Availability of pure and safe drinking water is an important need for every human being. Natural sources and industrial effluents contaminate water profusely at different levels. One such contaminant is fluoride which is a normal constituent of natural water. Its excessive intake (more than 1.5 mg/l) may lead to dental fluorosis or crippling skeletal fluorosis, which is associated with osteosclerosis, calcification of tendons and ligaments, and bone deformities. People of the countries particularly in warm climates, where groundwater naturally having a high content of fluoride and water consumption is greater, or where high-fluoride water is used in food preparation or irrigation of crops are highly exposed to devastating effects of fluoride. However, the global prevalence of dental and skeletal fluorosis is not entirely clear, it is estimated that excessive fluoride concentrations in drinking water have caused tens of millions of dental and skeletal fluorosis cases worldwide over a range of years. Although removal of excessive fluoride from drinking water may be difficult and expensive, low-cost solutions that can be applied at a local level do exist. As fluorosis is an irreversible process and has no cure, prevention is the only cure for this menace. Thus various defluoridation methods have been investigated and explored to identify their utility and potential for effective fluoride removal. These methods have their own merits and demerits. While most of them are not very successful especially under most prevailing conditions in remote areas of developing countries and thus it is very critical to identify the most appropriate method of defluoridation. In recent decades, researchers are trying to explore various effective community and household water filter systems for defluoridation but their high cost and difficult operating conditions restricting their use and adaptability by the lower-income groups of society. Thus there is an emerging need to develop efficient and cost-effective filters for effective defluoridation, affordable by all sections of society. Domestic water filter systems are more appropriate than community-based filter systems due to their low cost, easy operation, and maintenance. Various such filters are being explored for effective defluoridation in recent years. In this context, the present review is aimed to arrange the information available on point-of-use low-cost domestic filters developed for fluoride removal across the globe with special reference to India and their comparative analysis.