ABSTRACT
This communication, which deals with the relationships between the geological environment and health problems, highlights the endemic fluorosis and explores the harmful effects of fluorosis to the human beings and for an applicative research of endemic disease control. Fluorosis, caused due to drinking of fluoride contaminated groundwater is a major environmental health hazard throughout the world—USA, Europe, UK, and other countries, including India, spreads now among 67 million people in the entire arid and semi-arid tracts of India. Endemic fluorosis is of recent origin and developed due to certain faulty water management practices. According to UNICEF, more than 1.5 billion people worldwide do not have access to safe drinking water, leading to infectious diarrhea and other viral infections. In some areas, groundwater may contain enhanced levels of natural substances like arsenic, fluorine, nitrate, sulphate etc. that can restrict or prevent the use of groundwater because of health concerns. Although several sources of fluorine have been mentioned, only fluoride content in ground waters has been studied in the present investigation. It has been found that the levels of fluoride content are varying from 0-16.2 mg/l. Only a few samples in the study area, in Anantapur District, South India are found to contain the extreme values nearing 10.0 mg/l or even more. The reason for these extreme values may be due to the direct contact of waters with fluoride minerals.
If fluoride content is around 1.5 and 2.5 mg/l, mild dental fluorosis/mottling may appear and this disorder was caused in children drinking high-fluoride water. A more severe type of fluorosis called "Skeletal Fluorosis or Osteofluorosis" may develop, if the fluoride content of drinking water is in excess of 3.0 mg/l, among adults under Indian conditions, affecting bones and joints. It has been found that the levels of fluoride content are varying from 0-6.2 mg/l. The work at National Institute of Nutrition, Hyderabad, in 1977, has revealed the spread of endemic 'Genu Valgum' (knock-knee), crippling lower limbs from childhood, in association with fluorosis in most parts in India. Although preliminary work revealed that genu valgum is caused by drinking waters poor in calcium and rich in molybdenum, exact causes are yet to be known, to prevent its wide-spread occurrence in the fluorosis areas of India. The authors' work revealed that the fluorine content of rocks in India at most places is much less than that in most developed countries. Despite that, the fluoride content of groundwater in India is much higher than in most developed countries. As a result, fluorosis caused by excess fluoride in water is wide-spread in India and dental caries caused by deficiency of fluoride in groundwater is wide-spread in most developed countries. The present investigation reports the distribution pattern of fluoride toxicity in waters of Anantapur District, Andhra Pradesh, India. The severity of the problem is more accurate as only 30% of the villages have the fluoride content in drinking waters within the permissible limit (1.5 mg/l) and 70% of the villages above the permissible limit (>1.5 mg/l). Attempts are made to ascertain the fluoride toxicity in waters of the study area, in Anantapur District and several measures have been suggested for follow-up action. It can be concluded, that fluoride upto 1.0 mg/l in drinking water is beneficial, anything in excess of 1.5 mg/l is associated with 'mottling of enamel of teeth leading to initial manifestation in children; and that in excess of 3.0 mg/l with skeletal fluorosis, leading to final manifestation in adults.
