Abstract

The Dry Zone of Sri Lanka has mostly poor rural folk, who live in very close association with the immediate physical environment, depending on it for their living. Many of these people have lived in such a confined environment throughout their lives and it is reasonable to assume that at least some aspects of their health could be correlated with the geochemistry of their immediate environment.

Hydrogeochemical investigations of surface well water and deep well water in parts of the Dry Zone notably in the North Central Province, have shown that the fluoride concentrations often reach anomalously high levels, of the order of 10 mg⁻¹ in some instances. As a result of this, dental fluorosis is increasing in its prevalence among school children. With over 13 000 tube wells with hand pumps, mostly in the Dry Zone, the problem of dental fluorosis will assume serious proportions in the future unless methods of defluoridating household water supplies are developed.

An attempt has been made to implement a programme of defluoridating water supplies with a defluoridator using charcoal and charred bone meal. However, a major awareness programme is needed to educate the villagers of the dangers of excessive fluoride in drinking water and the need for community participation in maintaining household defluoridators.