Murunga (“Drumstick”) (Moringa oleifera) and its claimed potential for water purification.
Posted on January 12th, 2017

Chandre Dharmawaradana [A shorter version appeared in the Island, 11-Jan-2016]

Two writers,  Dr. Pethiyagoda  (9-01-2016, Island) and Dr. Weeraratne (11-01-2016 Island) have raised the question why Sri Lankan scientists and government authorities are not moving to Murunga seed (seeds of Moringa Oleifera, or drumsticks”) to exploit  its claimed efficiency for water purification- a green solution”.  The two writers argue that Murunga seeds can remove alleged toxins from the water in the North Central province (NCP) and alleviate a serious chronic kidney disease  (CKD) found in the region. Dr. Weeraratne also refers to an international expert consultation (IEC) held in April 2016 regarding CKD, and says that 27 recommendations were made, and raises ire as to why they were not implemented.

However,  the IEC made no mention of  using  Murunga seed for water purification in any  of their recommendations. Since  Murunga seed” has been proposed every season by some writer, let us think through” the use of  Murunga to purify domestic water for the NCP.  A  family of five would need about 50 liters of water a day, allotting about three liters per person purely for drinking,  while a common 35 liters is left for cooking and other needs where the water is ingested/used  in other forms. Usually one Murunga kernal is needed for the purification of one liter of water. Hence the family needs 50 kernals of Murunga per day. Seeds have to be prepared everyday for water purification as they go bad once removed from the drumstick. A drumstick may contain a dozen seeds of which several may be bad or discoloured. If we assume  about 8 to 10 useful mature seeds per Mururnga drumstick,  we need 6-8 drum sticks  per day.  Their  current market cost is minimally Rs. 25 per day. Of course, if  even a tenth of the one million people in the affected area begin to buy  Murunga everyday the price will shoot sky high!

But this is not all;  the mature Murunga has to be processed before using  for cleaning water. There is no  ready-made product available in the Lankan market. The seeds have to be removed from the pods, shelled to get clean kernels, crushed  in a grinder or wangediya” and sieved to  a  fine powder (try this and see what a messy process it is!).  A paste of the powder made with  water is shaken vigorously  to activate” it. This paste  is added to the 50 liters of water from the well (or other source), stirred thoroughly and allowed to sit for a few hours. During this time turbidity and toxins get absorbed into the murunga-powder in suspension. The water is filtered and used for cooking, drinking etc. One member of the family  has to devote (at least) an hour for this daily ritual. At Rs. 800 a day (8-hour work day) typical of NCP labour, this adds Rs 100 to the cost of the 50 liters of water.  If done by a junior we may cost it at Rs 50. Hence the total cost is now Rs 75 for 50 liters, i.e., at least Rs 1.50 per liter of water.

Furthermore, what does the farmer do with the filtered sludge which now contains all the pollutants possibly causing kidney disease? He cannot put back the sludge into the soil to re-pollute the soil at a much higher concentration! The farmer may cut his costs by growing Murunga in his back yard. This will imply some labour, and a  two-year wait before  mature  produce Murunga. But unfortunately,  another danger looms over him – the threat of bio-accumulation of toxins in the Murunga plant.

The rice plant, when planted in most soils even with  less than 5 parts per billion of cadmium is known to concentrate such  toxins in its seeds, leaves etc, as shown by the chemical analysis of Sri Lankan rice by Prof. Meharg of Scotland, and confirmed by  recent detailed work by the team of Prof. Chandrajith at the geology department,  Peradeniya University. This however does not mean that the Sri Lankan rice  poses a health risk, because the plant has absorbed not only toxins like cadmium, but large amounts of mitigating substances like zinc and selenium, making it safe for consumption.  In fact, the work of Meharg, and Chandrajith and collaborators show that the rice from the WET ZONE contains significantly more cadmium than dry-zone rice! But the wet-zone rice is also compensated by mitigating substances and may be regarded as posing no health risk. It should be noted that oysters and many kinds of fish sold in Europe have more cadmium than Sri Lankan rice, but they are legally marketed because there too, mitigating substances like zinc are present  and suppress the effect of cadmium.

Not only rice, many other grasses, plants and trees bio-accumulate” toxic metals from the soil during its growth.  The chemical analyses of the NCP soil and water by independent scientific organizations have shown the absence of  significant amounts of metal toxins or residues of pesticides like glyphosate in the NCP. But glyphosate has been banned on the assumption that it is there, and causing chronic diseases! The problem lies in the capacity of plants like rice or murunga to bio-accumulate even from trace concentrations. The WHO-NSF study revealed that lotus root and kohila (Lasia spinosa) were rich in accumulated metal toxins, and recommended their avoidance.  The murunga tree’s leaves, pods etc.,  are likely to be rich in toxins. Does murunga have accumulations of mitigating ions in sufficient amounts? While this is likely, no analysis is available, unlike in the case of rice. Most of the murunga available in Indian groceries in Canada come from South India, and I hesitate to consume the product.

Is there a strong reason to worry about vegetables and food stuffs imported from India? Indeed. The level of public hygiene and sanitation in India is certain much lower than Sri Lanka at present. In addition, India has a very large number of coal-powered power stations which spew out cadmium and other metal toxins. India has much more extensive mining and smelting activities, polluting industrial activities like dying and textiles  that have serious consequences to the environment, especially in the absence of any effectively enforced  environmental regulations. However, India is not as polluted as southern China which had embraced exponentially rapid growth with little regard to pollution.

If the murunga kernals have accumulated toxins, adding powdered murunga-seed  to water may pollute the water even more! All this shows that before we apply some magic remedy”, or adopt some trick”  triumphantly broadcast by  false internet gurus”  like Dr. Mercola, we need to follow the standard route of scientific investigations. These will include a chemical analysis of the murunga pods before use in the water, and a chemical analysis of the water as well as the filtered sludge, especially for Cd, As, Fluoride etc., at parts per billion accuracy before the method can be applied for public use. In Bangladesh, well-meaning international organizations installed free”  tube wells for providing water to rural people, without a chemical analysis of the water obtained from the tube wells. Unfortunately, the tube-well water contained high levels of arsenic, creating a human catastrophe which has gone on for decades. In Sri Lanka, an expensive high-tech water filtration process known as Reverse-Osmosis (RO), often used to purify sea water,  was introduced  at great cost for giving  clean water” to the residents in the NCP, when it was later found by a team of engineers of the National Water Board that the input water was already quite clean (i.e., no significant amounts of toxins) and did not need expensive RO installations! However, the people  have become panicked by the propaganda about the presence of toxins (Vasha-Visha”) and  buy RO water at prices  ranging  from Rs 0.25
to Rs 1.0 per liter, compared to Colombo citizens who get potable piped water for a thuttuwa”.  As we see, even RO water is cheaper than water cleaned using Murunga-seed powder, costing Rs1.50 per liter of water!

The cheapest and fastest way to provide clean water to the NCP is to harvest rain water, successfully used even in Uganda where the rainfall is a tenth of that in the NCP.  A large (plastic) tank is needed and this  initial cost (about Rs. 50,000-70,000 per family)  can be amortized over 20-30 years. Then a liter of clean water costs less than one cent. Several organizations in Sri Lanka have experience in this, and are helping the NCP residents to harvest their rainwater, while leaving Murunga to the elite organic-food  lobby.

11 Responses to “Murunga (“Drumstick”) (Moringa oleifera) and its claimed potential for water purification.”

  1. aloy Says:

    “…buy RO water at prices ranging from Rs 0.25
    to Rs 1.0 per liter, compared to Colombo citizens who get potable piped water for a “thuttuwa”. As we see, even RO water is cheaper than water cleaned using Murunga-seed powder, costing Rs1.50 per liter of water!”

    I would like to write few lines about this statement. There is a program going on by Water Board to replace the PVC pipes that are supplying water to residents in CMC area with HDPE (high density poly ethylene) pipes. The reason being there is a leakage of 50% of water being pumped to the city. This is falsehood. The water is being stolen through illegal connection, as such many residents may not be even paying even the “thuttuwa”. The photographs taken by me during the course of the these laying in one lane by me, perhaps would give a clue.

    Moringa capsules are being taken by many in the part of the world where I work. Ten Moringa seeds are being sold in agric shops for about Rs.100. I do not know for what purpose they buy the seeds. But Moringa trees are grow abundantly in those countries and are known by that name. Murunga is used extensively in aurvedic concoctions and may be containing some substances that would remove toxins or may fight bacteria etc.

    As for toxicity in Sri Lankan rice, I have commented on this about the tests carried out by a Sri Lankan professor who was the head of Peradeniya agric faculty when he was working as an academic in an ASEAN country. Of ten countries he tested SL and India had the lowest level of toxic material in rice. Actually he is the one who found why the rice that was milled by small scale millers in SL had bad odour when being cooked. As a solution he promoted the WB funded loans from which Prez’s brother also benefited. When he was returning he told me that he might get involved in these ‘wasa wisa nethi’ progrmmes as he was known to the Prez as well, but instead we see people with other ideas engaged in them.

  2. NeelaMahaYoda Says:

    Those who support RO water and Rain water should note this information

    As an engineer in England I always specified re-mineraliasation unit or what we call Re-Hardening unit upstream of the storage tank. Re-hardening (neutralising or palatability) is the process of dissolving calcium and magnesium salts in the water to raise the pH to an acceptable level and give ‘taste’. it is achieved by flowing the water through a bed of an approved proprietary material.

    The neutralising equipment should be situated upstream of the main storage tanks to ensure stable flow rates and it should be provided with a by-pass line so that final pH can be adjusted.

    The long-term health effects of drinking demineralized water are deprived mineral intake that can affect our organs and functioning of our tissues and bones as also our immune system. So drinking desalinated whether it is RO water or rain water is not advisable.

    We need re-mineralization to partly replace essential minerals removed from the water by desalination. Although this process has proved to be costly and not very convenient

    Even though food is a much richer source of calcium and magnesium intake than water, demineralized water can significantly affect the balance of these key minerals in the body.

    One of the reasons for this is because “the elements are usually present in water as free ions and, therefore, are more readily absorbed from water compared to food where they are mostly bound to other substances.”

    Many studies throughout the world have reported that people drinking water that is low in calcium and magnesium (i.e., soft water) is tied to higher incidence of death from cardiovascular disease compared to those drinking regular water.
    Recent studies also suggest that the intake of soft water may be associated with a higher risk of fracture in children and decreased bone density in adults.

    In addition, studies found that cooking with demineralized water caused a huge loss of essential elements from most foods. In some cases, the loss of calcium and magnesium was as much as 60%.

    The possible adverse consequences of low mineral content water consumption are discussed in the following categories: • Direct effects on the intestinal mucous membrane, metabolism and mineral homeostasis or other body functions.
    • Little or no intake of calcium and magnesium from low-mineral water.
    • Low intake of other essential elements and microelements.
    • Loss of calcium, magnesium and other essential elements in prepared food.
    • Possible increased dietary intake of toxic metals.

    Please read this article for more information

  3. Ananda-USA Says:

    I am providing this information for the benefit of expatriates who want to take a residential below-the-kitchen-sink water filtration system to Sri Lanka.

    I bought this 4-Stage Reverse Osmosis Water Filtration System (Pure Blue H20 Model # PB-TLRO 4H50T) from COSTCO ( for 129.00 USD (Rs 20,850 at Rs 150/USD) before tax. I bought it on sale 30 USD below the normal price of 159.00 USD. It comes in a 15in×16in×18in cardboard box weighing 21.0lbs.

    It has 4 twist-lock cartridges which can also be bought on the Web (Watts brand) for 50 USD for a set of 3 filter cartridges which must be replaced each year, and 65 USD for the RO membrane once every 3 years for a total of 72 USD (Rs 10,800) annually. One set of 3 filter cartridges and the RO membrane cartridge is included with the unit. It comes with a 5 gal tank with a pressurised internal rubber bladder which fills with purified water as the water is consumed from the pressurized water supply pipe that normally serves the kitchen sink. A swivelling water faucet, that can be installed on top of the kitchen sink in an existing hole or a custom drilled hole, is included with the unit. The whole system can be installed in about 30 minutes by an average homeowner.

    The treatment stages are:

    Stage 1: A 5-micron sediment filter to trap dirt, rust, sand, silt and suspended particles.

    Stage 2: High capacity solid carbon block technology to reduce chlorine taste and order and more…

    Stage 3: High production 50 gpd thin film reverse osmosis membrane to reduce contaminants as small as 1/10000 of a micron

    Stage 4: Final high performance solid carbon block to enhance the quality and taste of water

    It removes the following chemical compounds and particles from the tap water:

    Arsenic, barium, cadmium, hexavalent chromium, trivalent chromium, copper, fluoride, lead, radium 226/228, selenium, turbidity, tds, and cysts

    It is suitable for purifying drinking water, and beverage and cooking water.

    I used this system for about 5 years in my home kitchen in the US before I installed a whole house system including bathroom and washing water supplies, although the city tap water was potable directly without further purification.

    I will install the unit I bought recently in the kitchen of my home in Sri Lanka that also has a separate expensive wall-mounted system sold by Damro for supplying the refrigerator chilled water system.

    Assuming consumption of 50 gpd (rated capacity), and excluding the initial cost of approximately 20,000 SLR for the unit, the recurring cost is 10,000 SLR for 365×50 = 18,250 gals. That is, approximately 0.55 SLR/gal of RO purified water. Estimating a lifetime of 15 years for the unit, the prorated cost of the unit is an additional 20000/15 = 1333 SLR/ year, or about 10 percent increase above the cost of filter cartridges (neglecting interest on the cost of the unit).
    Therefore, the exact per unit cost of RO purified water using this residential under-the-kitchen-sink system is 11333/18250 = 0.62 SLR/gal, or 31 SLR/day for a daily consumption at the maximum rate of 50 gpd.

    This is quite a bit more than the cost of RO purified water using a large scale centralized system, but I think it is quite affordable for most middle-income homeowners in Sri Lanka who place a premium on their health.

  4. aloy Says:


    The carbon block (perhaps activated) is the one that removes the active ingradients like Cadmium etc that may be harmful. Some others like selenium may actually be beneficial to people. Selenium tablets are being sold as health products.
    How many times did you replace the carbon block etc. during the five years as there must be a limit for its absorption capacity?. These maintenance costs also should go into the analysis.

    I think the best solution is to give water to NCP farmers through the Moragahakanda project being constructed as a result of the Prez effort. Let them get another ‘loan’ and help all the farmers in those affected areas and solve the problem once and for all. may be the Chinese could be persuaded to spend the $200m that is earmarked for the research programme for this useful work instead.

  5. NeelaMahaYoda Says:


    I agree with you that the best solution is to give water to NCP farmers through the Moragahakanda project being constructed as a result of the Prez effort. Let them get another ‘loan’ and help all the farmers in those affected areas and solve the problem once and for all. may be the Chinese could be persuaded to spend the $200m that is earmarked for the research programme for this useful work instead.

    What Ananda has never noticed is that when you remove Arsenic, barium, cadmium, hexavalent chromium, trivalent chromium, copper, fluoride, lead, radium through a RO membrane, inevitably it removes useful minerals like magnesium and calcium down to zero.

    If we continuously drink water that are derived of these two minerals, there will be long term negative impacts on our overall health, which is actually the opposite of what we want to achieve via filtered water

    Carbon block is apparently not a re-mineraliser. Re-mineralisation is the process of dissolving calcium and magnesium salts in the water to raise the pH to an acceptable level and give ‘taste’. it is achieved by flowing the water through a bed of an approved proprietary material

    To explain in simpler language, demineralized water isn’t the safest drinking water for you health for these 4 reasons:
    1. Negatively effects various aspects of our biology,
    2. Does not provide minerals essential to our health,
    3. Strips foods of essential minerals when used for cooking, making juice, baby formula, etc.,
    4. Attacks metal surfaces such as copper and lead plumbing and fittings, tanks and even bottles, dissolving metals and other impurities into the water.

    “Sufficient evidence is now available to confirm the health consequences from drinking water deficient in calcium or magnesium.
    Many studies show that higher water magnesium is related to decreased risks for CVD and especially for sudden death from Cardiovascular Disease (CVD). This relationship has been independently described in epidemiological studies with different study designs, performed in different areas, different populations, and at different times.

    In addition to an increased risk of sudden death, it has been suggested that intake of water low in magnesium may be associated with a higher risk of motor neuronal disease, pregnancy disorders (so-called preeclampsia), sudden death in infants, and some types of cancer.

    Recent studies suggest that the intake of soft water, i.e. water low in calcium, is associated with a higher risk of fracture in children, certain neurodegenerative cardiovascular diseases, pre-term birth and low weight at birth and some types of cancer.”

    Health of infants feeding powdered infant formula are are in great danger as infants consume drinking water from the day they are born owing to the fact that it is used to reconstitute the milk. Their mineral intake only through the drinking water used for preparing infant formula up until complementary foods are introduced.

    There are many RO systems now available in the US and UK market with re-mineraliser unit incorporated in the system. A few of them are ; Home Master, Aquasana AQ RO3 ,and Abundant Water Flow ro system

    Another way to remineralise osmosis water is to add an water ionizer in your current reverse osmosis system set up. It is basically a time based filter that will release minerals into your drinking water at pre specified timing. It is the only way to enable remineralization for RO systems that don’t have a built this being built in.

    However, adding a water ionizer is not cheap. Most will cost around USD140+. Hence, this is why I insist on buying a reverse osmosis water system that has this being built in. It is way cheaper and saves you time on doing further installation.

  6. Ananda-USA Says:


    As I STATED in my comment above, the 3 filter cartridges are replaced annually and the RO membrane is replaced once every 3 years.

    I did include the cost of these consumables to arrive at the cost estimate of 0.62 SLR/gal or 31 SLR/ day for the maximum capacity of the unit of 50 gal/day of purified water consumption.

  7. Ananda-USA Says:


    I too think the carbon block filters are made from activated carbon which is a standard in adsorption type filters. These are especially effective for removing carcinogenic chlorinated hydrocarbons like TCE for which the EPA groundwater limit is very low at 5 ppb. I think the compacted block construction of the carbon block is for reducing the pore size and exposing a much greater surface area to the flow, as well as capturin loose particles that originate within the filters themselves.

    BTW, in my varied professional career, I have worked in Groundwater and Environmental Remediation R&D areas also. They included industry standard pump and treat and air-stripping methods, and novel bioremediation techniques including the installation of insitu-microbial biofilters seeded with microbes developed in laboratory bioreactors.

  8. Ananda-USA Says:


    Thank you for bringing up the issue of the need to remineralize rainwater or RO water with Ca and Mg elements, but there are simple ways of offsetting that deficiency as I describe below.

    In my write up on an inexpensive 4-stage RO system elsewhere I also mentioned my having installed a much more expensive whole-house RO system. That system has the remineralization feature that you referred to.

    This issue of remineralization is not always important, because the simple act of taking a daily vitamin pill, with more than the RDA of not only vitamins but also essential minerals, can offset any deficiencies in a person’s dietary and liquid intakes.

    If a person can afford to buy an RO unit with the remineralization feature built in, that is good, but I happen to think that EVERYBODY, especially in SL where people don’t pay attention to eating a balanced diet, should take a daily vitamin+mineral pill while paying more attention to the more important issue of avoiding drinking and cookinh use of contaminated water.

    It would be useful if you present for us at LankaWeb the specifications and cost data on the 3 brands of RO units with remineralization that you presented. Please be sure to specify both the list of contaminants removed and the water purification capacity in gpd.

  9. Ananda-USA Says:


    You correctly pointed out

    “1. Negatively effects various aspects of our biology,
    2. Does not provide minerals essential to our health,
    3. Strips foods of essential minerals when used for cooking, making juice, baby formula, etc.,
    4. Attacks metal surfaces such as copper and lead plumbing and fittings, tanks and even bottles, dissolving metals and other impurities into the water.”

    biuut are these issues significant for the RO unit I presented and its mode of use, and can these effects be simply alleviated?

    Items 1 & 2: These are easily addressed through taking vitamin and mineral supplements in pill form, given that the main issue is protecting yourself from ingesting harmful contaminated water.

    Item 3: The problem of stripping of essential minerals from food and drinks REMAINS an issue, but can be partially offset by taking vitamin and mineral supplements in pill form as for Items 1 & 2.

    Item 4: The problem of electrochemical degradation of metal surfaces does not arise in the case of the RO system I presented because the produced RO water does not generally come into contact with such surfaces. This unit uses plastic and stainless steel fittings that are resistant to such attack, and the water will usually be accessed in a stainless or porcelain kitchen sink setting and used in plastic or glass vessels.

    However, if the water remains in contact with aluminum (usually protected by a chemically resistant Al2O3 oxide coating) or cast iron pans without teflon or ceramic coatings, leaching of metal into the water could become a problem. For the very restricted mode of use of this RO system, I think this issue is not significant.

    I don’t think that attempting to remedy nutritional deficiencies through the water supply is the best approach. Due to variability in the nutritional content of food and drink due to personal and community habits, locations, and indeed wealth of each consumer, there are many unaddressed nutritional vitamin and mineral deficiencies.

    These deficiencies may be best addressed by simply taking a vitamin and mineral supplement pill every day, rather than attempting to do it through the water supply.

    What is MORE IMPORTANT may be to provide a clean uncontaminated water supply, free of toxic chemicals, carcinogens, and heavy metals that may cause neurological disorders, in an inexpensive and cost effective way to each family.

    That was the thrust of my submission.

  10. Ananda-USA Says:

    I am sorry, but I made a mistake in my first comment on the RO system above.

    The expensive wall-mounted water purification filtration system that I installed in my home in Sri Lanka for supplying the refrigerator chilled drinking water was bought from ABANS and NOT FROM Damro.

  11. S.Gonsal Says:

    ABANs is OWNED and run by ARABS.

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