पीने के पानी में फ्लोराइड: - एक छिपी हुई ज़हर
An adequate water resource for future generations is not only a regional issue but also a global concern. Like other parts of world, India is also facing a water crisis and by 2025 it is estimated that India’s population will be suffering from severe water scarcity. Although India occupies only 3.29 million Km2 geographical area,
which forms 2.4% of the world’s land area, it supports over 15% of world’s population with only 4% of the world’s water resources. Groundwater contributes only 0.6% of the total water resources on earth; it is the major and preferred source of drinking water in rural as well as urban areas.
It caters to 80% of the total drinking water requirement and 50% of the agricultural requirement in rural India. But in the era of economical growth, due to various ecological factors either natural or anthropogenic, the groundwater is getting polluted because of deep percolation from intensively cultivated fields, disposal of hazardous wastes, liquid and solid wastes from industries, sewage disposal, surface impoundments etc.
Presence of various hazardous contaminants like fluoride, arsenic, nitrate, sulfate, pesticides, other heavy metals etc. in underground water has been reported from different parts of India. In many cases, the water sources have been rendered unsafe not only for human consumption but also for other activities such as irrigation and industrial needs.
Therefore, now there is a need to focus greater attention on the future impact of water resource planning and development taking into consideration all the related issues. In India, fluoride is the major inorganic pollutant of natural origin found in groundwater. In this article detailed account on sources, ill effects and techniques available for fluoride removal is done.
WHY FIGHT AGAINST FLUOROSIS?
Fluorosis, caused by excess intake of fluoride mainly through drinking water, affects several organs. The onset of the disease is marked by non – skeletal changes, which can easily be reversed by safe drinking water and nutritional intervention. In advance stages, the disease progresses into non-curable dental and crippling skeletal fluorosis.
MAJOR SOURCES OF FLUORIDE:-
Food and beverages including black tea, black salt, tinned food and juices.
Fertilisers and Pesticides containing fluorides.
Industrial emission and coal burning.
Drugs containing fluorides like sodium fluoride tablets, antibiotics, antidepressants and anti-cancer agents.
MAGNITUDE OF PROBLEM:-
There are more than 20 developed and developing nations that are endemic for fluorosis. In India it was first reported in Nellore district of Andhra Pradesh in 1937. At present fluoride endemicity has been reported in several districts of 19 Indian states and Union Territories. The affected population is 25 million and at risk is 66 million, including 6 million children below the age of 14 years.
HEALTH IMPACTS OF FLUORIDE:-
Fluoride in minute quantity is an essential component for normal mineralization of bones and formation of dental enamel. But, its excessive intake may result in slow, progressive crippling scourge known as fluorosis. Therefore fluoride is also called as “Double Edged Sword.”
The most vulnerable or high risk groups for fluorosis disease include children, elderly people, pregnant women, lactating mothers, patients with cardiovascular diseases and patients with kidney ailments. As per B.I.S. the permissible limit of fluoride in drinking water is 0.7 – 1.2 ppm depending upon the temperature of the place.
The intensity of fluorosis is not merely dependent on the fluoride content in water, but also on the fluoride from other sources, physical activity and dietary habits.
VARIOUS FORMS OF FLUOROSIS: -
DENTAL FLUOROSIS- Symptoms manifests in the form of yellowish, brown- black discoloration of the teeth. The discoloration may be seen as spots or streaks, invariably horizontal in orientation. The enamel may be pitted, rough and hard to clean. It becomes a permanent feature. Children are highly susceptible to dental fluorosis and the major sources include water with high fluoride content, certain food items, tinned food and certain toothpaste.
SKELETAL FLUOROSIS - Skeletal fluorosis affects children as well as adults. It does not easily manifest until the disease attains an advanced stage. Fluoride mainly gets deposited in the joints of neck, knee, pelvic and shoulder bones and makes it difficult to move or walk. The symptoms of skeletal fluorosis are similar to spondolytis or arthritis. Early symptoms include sporadic pain, back stiffness, burning like sensation, pricking and tingling in the limbs, muscle weakness, chronic fatigue, abnormal calcium deposits in bones and ligaments. The advanced stage is osteoporosis in long bones and bony outgrowths may occur. Vertebrae may fuse together and eventually the victim may be crippled. It may even lead to a rare bone cancer, osteosarcoma and finally spine, major joints, muscles and nervous system get damaged.
Once the skeletal fluorosis has set in, there is no available cure. Rehabilitation of crippling skeletal fluorosis patient requires joint bone surgery. The only effective remedy is prevention. This can be easily accomplished by resorting to use of safe drinking water and improving nutritional status by incorporating calcium, vitamin E, vitamin C, and anti-oxidants in diet.
NON–SKELETAL FLUOROSIS: - Besides skeletal and dental fluorosis, excessive consumption of fluoride may lead to muscle fibre degeneration, low haemoglobin levels, deformities in RBCs, excessive thirst, headache, skin rashes, nervousness, neurological manifestations, gastrointestinal problems, abdominal pain, tingling sensation in fingers and toes, reduced immunity, male sterility, etc. Consumpton of water and food high in fluoride by a pregnant woman can damage foetus. Breast feeding by such mothers may also pass on fluoride to the infants. Abortions, still births and deformed babies can also happen due to fluorosis.
PREVENTION AND CONTROL OF FLUOROSIS:-
A community with excessive fluoride in its water supply may prevent or minimize the problem by the following ways:-
Exploring alternate water sources.
By improving the nutritional status of population at risk.
Removal of excess fluoride (defluoridation).
EXPLORING ALTERNATE WATER SOURCES
Alternate water sources include surface water, rain water and low fluoride groundwater. More often, surface water is heavily contaminated with pollutants; it cannot be used for drinking purposes without treatment, making it too expensive for application in poor communities. Rain water is usually a much cleaner water source and may provide a low–cost simple solution, but it has its own limitations. The fact that fluoride is unevenly distributed in groundwater and its concentration keeps on changing with time both vertically and horizontally, implies that every well has to be tested and regular monitoring has to be done.
FLUORIDE TESTING: -
A variety of methods including Colorimetric(SPADNS), photometric and ion-selective methods for testing fluoride are available. The most accurate and reliable method for testing fluoride in drinking water is the ion-selective method using ion-meter. 139 district laboratories throughout the country have ion-meters cum trained manpower for testing fluoride in water.
Anyone can also approach the water supply department of their respective area with water sample to be tested for fluoride. The panchayats and members of the community, including teachers and educated youth, can monitor water quality with the help of reliable and user-friendly field kits developed by the Central Pollution Control Board, New Delhi.
Clinical research indicates that intake of vitamin C, E, Calcium and anti-oxidants helps in the prevention and control of skeletal and non-skeletal fluorosis.
DEFLUORIDATION OF WATER
It is the only practicable option to overcome the problem of excessive fluoride in drinking water, where alternate sources are not available. One of the cost – effective and efficient techniques is described as follows:-
DEFLUORIDATION BY NALGONDA TECHNIQUE (DEVELOPED BY NEERI, NAGPUR):-
This can be carried out in a container of 60 Litre capacity with a tap 3-5 cm above the bottom of the container for the withdrawl of treated water after precipitation and setting.
The raw water taken in the container is mixed slowly with adequate amount of aluminium sulphate solution (alum), lime or sodium carbonate and bleaching powder depending upon alkalinity and fluoride content. Alum solution is added first and mixed well with water.
Lime and sodium carbonate solution is then added and the water stirred slowly for 20 minutes and allowed to settle for nearly one hour and is then withdrawn. The supernatant, which contains permissible amount of fluoride, is withdrawn through the tap for consumption. The settled sludge is discarded.
The most important aspect of prevention and control of endemic fluorosis is to create awareness among people. Indiscriminate use of fluoridated toothpastes and mouth rinses should be minimized and a proper standard should be maintained. Research work for the development of proper deflouridation techniques should be propelled, however the emphasis should be on the development of economical, spontaneous and easy to handle techniques.
In a country where there is water scarcity in general, it is a herculean task to tell a great majority of people to take low-fluoride water. People have been consuming water from various sources, including open ponds, bore wells and hand pumps. Hence it is imperative that the policy makers and administrators take it upon them to inform and educate the people about the problem.
A sustained public interest campaign through various media – both mass and interpersonal will help in disseminating information and educating people about the problem of fluorosis and the remedies. People’s participation through panchayati raj institution and collaboration with voluntary agencies are essential for providing safe water supply.
Anjani Kumar1, Rameswar Prasad Sah1 and Dileep Kumar2
1 Birsa Agricultural University, Ranchi, India
2 Banaras Hindu University, Varanasi, india