Dr. Ranil Senanayake’s criticism (The Island 22/9/2022) of Dr. Parakrama Waidyanatha’s article which appeared in The Island (19/9/2022) on the lifting of the ban on glyphosate is unfair and does not conform to what is already known. Glyphosate was banned without any scientific basis solely for political reasons. Glyphosate use in Sri Lanka can be traced to 1977, when it was permitted to control weeds on tea plantations. Glyphosate was approved for paddy soils in 1998 but paraquat, which was cheaper, was widely used at that time. When paraquat was phased out by the government in 2014, glyphosate came into regular use. The chronic kidney disease in the North-Central Province had been there long before 2014 and glyphosate absolutely has no role in causing the kidney disease. Furthermore, chronic diseases such as the Rajarata kidney disease manifest only after about 15-20 years of continuous exposure to a toxin. Scientific research has shown that glyphosate undergoes total degradation to harmless glycine and phosphate in the soils in about 7 days. Also, these studies reveal that glyphosate binds strongly to soil and there is less likelihood of it getting leached into the irrigation canals and reservoirs. When applied to paddy fields what is important is whether glyphosate goes into the paddy seeds. It is important to realise that paddy is harvested at least two months after the glyphosate is applied and hence there is no likelihood of the rice seeds getting contaminated.
Dr. Senanayake talks about the biomagnificationm, which is valid not only for glyphosate but also to many other poisons which enter our bodies. An earlier study carried out at the University of Peradeniya revealed the presence of ultratrace levels of pesticides in the drinking waters at Peradeniya. These originate in the widespread use of pesticides in the Nuwara Eliya District. These trace levels of pesticides accumulate in the fatty tissues, a process called bioaccumulation. Human body has a remarkable way to get rid of these poisons; the liver acts as the waste treatment plant and these poisons are detoxified in the liver and excreted through the kidney. However, excessive overloading of our bodies with toxic materials can be detrimental to our health. Dr. Waidyanatha correctly points this out when he says that it is the dose that matters. This in no way justifies excessive use of pesticides in agriculture.
Dr. Senanayake should realise that while organic agriculture practised prior to the 1960s in Sri Lanka was still not sufficient to provide enough rice for its population. The population of Sri Lanka was around 7 million in 1948 and it has increased to about 22 million today. Organic paddy farming can at best provide rice for only about 5 million and even during British rule, rice was imported the country starting from the 1920s. Therefore, agrochemicals are a necessary evil to feed a hungry population. The alternative is to import rice from other countries often having elevated levels of heavy metals such as arsenic and cadmium.
As regards the chronic kidney disease, scientific research has firmly established that fluoride in combination with hard water is what causes it. It is certainly not caused by irrigation waters contrary to Dr. Senanayake’s claim. The absence of the disease from Anuradhapura and Padaviya townships, where people consume water from irrigation tanks clearly, shows that all these agrochemicals ending up in reservoirs play no role in causing the kidney disease. Perhaps, he is referring to a publication by agriculturists at the University Peradeniya, who postulated that there were very high levels of cadmium arising from the agrochemicals washed out from the hill country ending up in Rajarata reservoirs. There is absolutely no evidence to suggest that people who consume irrigation waters are affected by the kidney disease. Several independent researchers have rejected these high cadmium levels because the values for cadmium in water determined at several laboratories in Japan, Germany and Sri Lanka using advanced instrumentation obtained values which are thousand times lower. I am aware of the basic errors in the analytical methods used by these agricultural scientists which led to such high values of cadmium and there is no independent confirmation of these results.
A comprehensive study from the Ginnoruwa area in the Mahaweli Zone C clearly establishes the distinctive role played by fluoride and water hardness causing kidney disease. There are two villages in this area, Sarabhoomi located along the banks of the Mahaweli river and Badulupura located at a higher elevation. While Sarabhoomi has zero kidney patients, Badulupura has over 30% of its adults affected by kidney disease. People in Sarabhoomi consume water from the river itself or from shallow wells located close to the river with low levels of fluoride while Badulupura residents get their water from deep wells which are invariably rich in fluoride and hardness. Hence the argument that irrigation water contaminated with the agricultural runoffs from the hill country causes the kidney disease does not explain why Sarabhoomi residents are not affected by this disease.
I have worked on the Rajarata kidney disease from 2003, when it first came to the limelight and visited most of the areas affected and all kidney patients have consumed fluoride rich water without exception. Most of these patients come from areas far away from any major reservoirs. As a result, they had to dig wells in the remote areas and these invariably reach the bed rock and fluoride leaching from the rocks resulted in the excessive fluoride in these wells. In the ancient agricultural civilisations of Sri Lanka, people lived close to the main reservoirs or its canals and used water from these sources and these invariably had low fluoride levels. However, with the colonisation schemes starting from the 1950s people were provided with lands far away from these reservoirs and they had to dig deep wells to provide them with water. This is the reason why this disease is of relatively recent origin.
In one study from Chettikulam, people are affected not only by the kidney disease but also skeletal fluorosis. The provision of purified water to this area resulted in a considerable reduction of progression of the disease and people who could not even stand up are now doing their previous professions. One patient who was asked undergo a kidney transplant is now able to carry out his farming activities and the doctors have now declared that a transplant is no longer necessary. All these people use water from deep wells and there are no irrigation canals nearby. It is patently clear that the high fluoride levels in their drinking water has caused the disease.
One has to be practical in promoting the popular slogan of toxin free agriculture. Decades of dedicated research by our agricultural scientists have resulted in self-sufficiency in rice. Banning agrochemicals will have a disastrous effect on agricultural productivity. We already see the ill effects of the unwise decision to ban agrochemicals in 2019 which has resulted in severe food shortages and escalating prices of agricultural produce. Public should not be misled by fanciful theories of organic agriculture which only help to create unwarranted and unfounded information about kidney disease and other health effects of agrochemicals and glyphosate.