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Combating Fluoride Contamination in Guwahati, Assam: Recommended Action?

A part of Guwahati City is already affected with contamination of Drinking water sources with Fluoride. Very recently, the problem has been figured out in some fresh areas with Fluoride contamination of water above permissible limit ( in different ranges upto 3.86 ppm ).

We have advised people from those areas, to avoid such water sources and also to ensure some tips on the food habits as follow.

(a)    Use of safe water source. If needed, an RO may perhaps be used for this purpose. But such RO should be of adjustable nature, so that the TDS level in the water from this RO does not come down to zero, but remains in the level of at least 50 ppm.    

(b)    Regular intake of Milk, Curd, Ladies Finger ( Vindi ).

(c) Habit of consuming foods rich in Vitamin – C like Amla, Lemon etc.

(c)    Avoiding strictly the foods with black salt like, Chips, Fried Channa, Dalmut, Choclate etc.

However, we like to know whether there should be any addition or alteration or any new approach to be adopted into our advise as mentioned above?

Nripendra Kumar Sarma

Guwahati, Assam




Dear Nripendra Kumar Sarma,

We did extentive work on the fluoride problem in groundwater in Karbi Anglong district of Assam. Fluoride contamination is common in rain poor regions, i.e. arid regions like Rajasthan, Karnataka etc. To our surprise, Assam even though receives highest rain fall, has fluoride problem in groundwater.

Our investigation shows that the fluoride is originating from deeper hard rock aquifers (granites) and leaking into the shallower aquifers through regional faults. Our data is supported by the C14 ages on the groundwater from the shallow and deep hard rock aquifers. In addition to this, there is a inherent heat provided by the granites to “pump” more fluoride into the groundwater due to water rock interaction. We presume a similar situation in the area in Guwahati. The surface water is free from fluoride.

Now several methods have been adopted to mitigate this problem (defluoridation methods using alam etc). This will not work for a longer time since these techniques have their own inherent set-backs. While analyzing a similar problem in Karnataka, we find that fried tamarind seed powder is able to remove fluoride from water to certain extent. Assam and Karnataka are wide apart from their geographic localities, food habits and culture.

Again, in Assam, groundwater may not be the sole cause of fluorosis. This has to be analysed. For example, people in Tibet are severely affected by fluorosis even though the water they drink is free from fluoride. Here the problem is tea. The tea the Tibetans drink has high content of fluoride. One has to see whether similar problem exists in Assam also.

Having said this, I feel that surface water appears to be the best option to contain fluorosis. Guwahati has several natural streams and less polluted. The surface water can be boiled and consumed. This could be the best solution. Alternately, piped water can be provided to the communities. I know that this is easier said than done because, the communities are wide spread and it is difficult to provide piped water supply.

With regards,

Prof. D. Chandrasekharam
(Former Senior Associate, Abdus Salam International Centre for Theoretical Physics, Trieste; Chairman M/s GeoSyndicate Power P Ltd.)
Head, Department of Earth Sciences
Indian Institute of Technology-Bombay


Dear Mr.Sarma,

It was interesting to know that you have a problem of excess fluoride in water at a place like Guwahati. High fluoride only comes with ground water( water from bore wells,open wells). Fluoride is not present in surface waters such as river water. I thought Guwahati gets all its water from the Brahmaputra. If this is not the case, I would like to see a full test report to see what the water is like.

Your advice to people as I can see is to see that they focus on their nutrition by adopting a good diet. An RO plant can reduce the fluoride levels but it is not possible to prevent/adjust TDS levels from the outlet of the RO plant.In fact RO is not the answer.

Fluoride removal plants are manufactured in India and have been installed in areas which have high fluoride levels in water.For those areas of Guwahati city which have this problem, a De-fluoridation plant could be installed in each such locality.If you need help with this please let me know.





Dear Nripendra Kumar Sarma,

Alternative source is the best possible solution. R.O may not be a feasible solution for economacally weaker section.

People may be advised to go for Rain water for Drinking & cooking purpose as rainfall intensity in Guwahati is around 1650 mm per year.

I come to know that there is proposal to cover entire Guwahati within 2010. Perhaps this problem could be avoided by that time.

Till then your suggestion may be enough.

With regards,

Diponkar Bordoloi
Assistant Engineer
Public Health and Engineering Department (PHED)
Guwahati, Assam


Dear Sarma,

When drinking water has high concentration of fluoride, the best course of action would be to shift the water source to that having a fluoride of less than 1.5 mg/L. When this is not possible, the next best course of action would be to resort to partial defluoridation of water. There is no point in resorting to reverse osmosis when water has high concentration of fluoride but otherwise good in quality.

What is important is to hire the services of a company that provides application-specific water treatment solutions that includes defluoridation. Details of one such company are furnished below.

Techline Green Pvt. Ltd
#36, S. R. Layout, Murgeshpalya
Bangalore - 560 017, Karnataka, India
Phone: +(91)-(80)-25210855 / 41488363
Fax: +(91)-(80)-41488363 / 25278083

Wish you good luck with your task to provide potable water in areas of Guwahati where groundwater has high fluoride content.

Dr. R. Jagadiswara Rao
Retired Professor of Geology
Sri Venkateswara University
Tirupati, AP 517502
(Presently on a visit to USA)

Dr. R. Jagadiswara Rao, Professor of Geology Retired, Sri Venkateswara University, Tirupati, AP 517502, India


Dear Nripendra Kumar Sarma,

In the areas where the groundwater is main source of drinking water, treatment is the only option before its public use. The method involves the use of fluoride exchangers like tri-calcium phosphate or bone meal, anion exchangers like activated carbon, magnesium salts or aluminum salts. For domestic defluoridation, Nalgonda Technique is the simplest one.

It involves the use of ammonium salts and a sequence of precipitation, settling and filtration. The technique can be used equally well for domestic as well as community water supply schemes.

Thanks and with regards,

Mahendra Pandey
ENVIS Coordinator
New Delhi


Dear Nripendra Kumar Sarma,

I would suggest that first of all people should look for alternate source of water. It may be surface water or it may be ground water from other areas where the fluoride levels are low.

Secondly, it has been found in many researches that the water which is pumped out from the shallow hand pumps is having more fluoride. If the pump is drilled deep then there will be no fluoride problem.
Further ginger can be added in the diet.

There should be regular monitoring of water quality and health impact monitoring in on humans.

The water sample be get tested from other laboratories also to confirm the results.

Thanks and with regards,

Dr. V.K.Garg
Associate Professor
Department of Environmental Science and Engineering
Guru Jambheshwar University of Science and Technology


Dear Nripendra Kumar Sarma,

Suggestions offered

• All ground water sources in an area should be tested for fluoride using Ion selective Electrode Technology (not field test-kits).

• Safe sources do co-exist along with fluoride contaminated sources.

• Safe water to be used for cooking and drinking purposes only.

• All processed food contaminated with fluoride, use of black rock salt, black tea drinking habits should be stopped.

• To promote the daily diet with adequate calcium, iron, folic acid, vitamin C, E and Antioxidants containing vegetables, fruits and dairy products to combat fluoride toxicity manifestations.

• As it has been suggested RO is the best option – do not attach conditions for that.

With regards

Yours sincerely

Prof. (Dr) A.K. Susheela
Executive Director
Fluorosis Research & Rural Development Foundation


Dear Nripendra Kumar Sarma,

Defluoridation is possible both at source of supply and at domestic level. Removal of fluoride ion is generally achieved by adsorption. In small supplies, use of locally available materials, such as charcoal made from rice husk or coconut shell, has been demonstrated. In larger installations, activated alumina has been used. For a place like Guwahati, the latter will be more appropriate.

At domestic level, alum solution if first dosed, followed by a mixture of lime and soda ash so that the trapped fluoride molecule is precipitated out.
Fluorides should not be totally removed; a concentration of 1 mg/litre helps in protecting teeth against caries.

Presence of fluoride in food is a separate matter. I have no comment on it.

With regards,

Paritosh Tyagi
Chairman (Retired)
Central Pollution Control Board
New Delhi


Dear Nripendra Kumar Sarma,

Please ensure testing of all ground water sources (tube wells/bore wells) and do mapping.

All families must be told about the quality of drinking water.

People must know which tube wells / bore wells are providing fluoride safe water.

It is better to supply treated surface water.

People can use cheaper defluoridation units. Activated alumuna packed filter is very good for defluoridation. Nalgona technique can remove excess fluoride effectively. R.O. unit is excellent for removal of excess fluoride; but it is costly. How poor people could afford to buy R.O. unit? Ion exchange unit can also remove fluoride.

However, capacity building is necessary for management of above mitigation measures.

Nutritional support as suggested, would be very much useful

Chakora bhaji can be popularised among the people.


Dr. Arunabha Majumder
Chairman, Indian Water Works Association (IWWA) and Ex-Director-Professor & Head, Department of Sanitary Engineering, AIIH&PH, Kolkata and Guest Lecturer, School of Water Resources Engg., J.U.


Dear Nripendra Kumar Sarma,

I feel, what you has written is very much useful.

Dr (Mrs) A K Susheela, Delhi, who is the pioneer in combating fluorosis, has almost same kind of suggestion for the fluorosis patients. I am giving below a little extended list of availability of those important vitamins and anti-oxidants to combat fluorosis including water filters.

Most important is to change the source of water in use, which contains flouride. It is not necessary to use RO always. If there is permissible quantity of TDS in water and non-permissible quantity of fluoride, then one can go for a filter which can remove flouride alone such as AA (Activated Alumina filter) - this will be cheaper and also one need not have to throw away the important other minerals contain in water.

AA filter does not require any power. It works on gravitation. It only requires AA granules to be regenerated in a specific interval of time. And later after a specific rotation, AA granules are to be replaced.

As people should avoid Black salt, Daalmoth, Black tea etc they also should avoid toothpaste containing fluoride.

Drugs containing fluoride should also be avoided - like Anti-depressants, Anti-infective and Anti cholesterol drugs.

Diet should contain - calcium, iron, vitamins and anti-oxidants.

• Calcium is required for strong bones, teeth, membranes and other intra-cellular structures for various tissues. Gur (Jaggary) is a very rich source of calcium besides milk and dahi etc.

An adult require 1.0 gm of elementary calcium.

• Iron for enhancing the haemoglobin content - available in Beet root, Apple, raw and ripe banana and brinjal.

• Vitamin C and E are required for protecting the body from various diseases including fluoride poisoning and fluorosis.

• Vitamin C is available in Amla (gooseberry), Lemon, Milk, Dahi, green leafy vegetables, kamal kakdi etc.

• Vitamin E is available in vegetable oil, Nuts (Almonds, walnut, peanut), Whole gram cereals, green vegetables and dried beans, sprouted moong and chana etc.

• Antioxidants acts as 'scavengers' - body shall get rid of free radicals and thereby a chance of becoming sick is less. There are different kinds of Antioxidants are available in different fruits and vegetables: Papaya, Carrot, pumpkin, spinach, white onions, garlic, spring onion, apple, cherry and cocoa and also in tomato, pink guava, and water melon.

Most important is to manage the mix of all these, which requires a skill, availability and affordability.

Antioxidants are of different kinds, so one can take doctors advice for choosing what kind of anti-oxidant one should take.

I have mostly followed Dr A K Susheela's booklet. However I have put my own experience seven years also in it. Dr Sunderrajan Krishnan who is also working in mitigation of fluoride in our organisation has expressed the same views with me.

We shall be happy if these inputs help people of fluoride affected areas. For further details one can contact us without any hesitation.


Dr. Rajnarayan Indu
Joint Director
Centre for Action, Research and Education in Water (CAREWATER)
A Division of India Natural Resource Economics and Management (INREM) Foundation
Anand, Gujarat


Dear Nripendra Kumar Sarma,

You have not mentioned whether the source is a deep bore well and a distribution system or a hand pump. If it is a hand pump, marking unsafe hand pumps should be done.

Surface water, if possible (bacteriologically acceptable), is the best source. Other wise, you can advise them to switch to safe hand pumps. Rain water harvesting should be looked into, especially in a state like Assam.

As you have mentioned, technological options to remove excess fluoride can also offer solution to fluoride problem. But one has to look into the sustainability of these methods. I have attached information of two firms, who market domestic filters. You can get more details from them regarding their products.

Tea is one of the richest sources of fluoride. You can also advise people about this. Black Tea should be avoided.

High Grade Industries India Pvt. Ltd.,

Ion Exchange
Ion Exchange

With regards

Leela Iyengar


Dear Mr.Sharma

Apart from locating safer low fluoride sources and ensuring diet as suggested, its best to look at Fluoride removal technologies that are sustainable. RO with it high cost, operational expenses and dependence on power may not be the right solution always especially where TDS is not too high.

Technologies that do not involve special chemicals, acids and alkalies, expert supervision (as required in some cases of removal by chemical reactions / precipitation) and low to nil dependence on power are the ones to look for. Last but not the least they should also ensure that there is no adverse effect on the environment.

Sandeep C K
Ion Exchange (India) Limited

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