By Ranjith W. Dharmaratne Courtesy The Island

By now, it is common knowledge that a significant number of people from farming communities living in the North Central Province (herein referred to as Rajarata) suffer from Chronic Kidney Disease (CKD). Over the past three decades, a number of investigations on the causes of CKD have been conducted, but no conclusion has been drawn yet on what exactly is causing CKD in the Rajarata context. Although a number of theories have been proposed, none has been confirmed so far, due to the lack of evidence. There are arguments and counter-arguments within the scientific community as well as among laypeople and political circles. As more and more people suffer from CKD, it is concerning that there is still no solution on the horizon for this burning problem. Currently, the only options left for CKD patients are costly procedures such as dialysis and kidney transplant. Unfortunately, there is still not enough guidance and awareness for the Rajarata public on preventing CKD.

A crisis endemic to Rajarata?

The majority of CKD patients from Rajarata do not show any identifiable causes of CKD compared to their CKD counterparts elsewhere, such as long standing diabetes and hypertension. This observation leads one to determine that this particular disease, or at least the cause, may be endemic to the Rajarata area. In fact, in 2003, Dr. Tilak Abeyesekera reported a pattern of this CKD in Rajarata. Considering these observations, it is logical to narrow down our focus to the lifestyles on the said communities, in particular various environmental factors that directly affect people’s day-to-day lives. Some reports claim that more than 15% of residents of the affected areas are suffering from CKD. A significant number of reports have highlighted that mostly the males working in the fields are affected by the disease. A number of theories suggest that CKD occur due to cadmium, fluoride, arsenic, aluminum, mercury, uranium, vanadium, algal toxins, and phosphates. More recent theories mainly focused on the use of chemical fertilizers and pesticides, especially the use of the herbicide glyphosates.

A link to drinking water?

Although none of the above theories have been confirmed due to the lack of scientific evidence, in the Rajarata context, something almost all CKD investigators in Sri Lanka appear to agree on is the possibility of drinking water having a direct association with CKD observed in Rajarata. Therefore, it is important that we focus a bit more on drinking water in the affected region.

Unlike with many other diseases, CKD often has no symptoms until the disease has reached an advanced stage. Damages shown in certain areas of the kidneys of the CKD patients could indicate the possibility of an adverse effect of a potential toxic substance present in drinking water. Chronic exposure to drugs, occupational hazards, or environmental toxins can lead to chronic kidney diseases, so CKD in Rajarata may possibly be due to one of the above factors contaminating the drinking water of CKD affected people. It is important to note that most people living in Rajarata’s CKD-prone areas consume water from the groundwater and deep-dug tube wells. Therefore, it is reasonable to assume that a toxic element could contaminate groundwater in both shallow and deep wells. According to resident doctors in Rajarata, city dwellers who consume potable water supplied from water tanks do not suffer from CKD. These observations lead one to investigate the potential toxic elements in the groundwater that are harmful to kidneys. An examination of groundwater in the CKD-affected areas of Rajarata reveals the presence of an unhealthy amount of fluoride, and this finding is in fact the biggest reason to consider fluoride as the cause for CKD in early studies in the Rajarata context. However, due to the lack of supporting information on their hand, investigators at the time were not able to prove this theory, and therefore the theory of fluoride being the culprit was put aside. I have however, recently reviewed nearly hundred years of literature on toxicity of excess fluoride on animal and human kidneys, and established that there is a direct link between high fluoride levels in drinking water and CKD. The fluoride levels of groundwater consumed in CKD-affected areas range from 0.5 to 5 milligrams per liter (mg/L), a level well above the limit recommended for tropical countries by the World Health Organization (i.e. 1 mg/L). We see some reports showing alarming fluoride levels as high as 3.9 to 7.3 mg/L in groundwater in some of the affected areas. Also, the presence of widespread diseases such as dental and skeletal fluorosis is in Rajarata confirms that people living in these areas are highly likely poisoned by high amounts of fluoride.

Are children at a higher risk?

According to the United States (US) Dietary Reference Intakes (DRI) charts, the tolerable upper intake levels of fluorides for children is 1.3 – 2.2 mg per day. It is estimated that an average child consumes 10 cups (2.8 L) of water per day. Therefore, by drinking just 10 cups of water from a water source that has two 2 mg/L of fluoride, a child consumes 5.6 mg of fluoride. This is 2.5 times the maximum tolerable upper intake of fluoride for a child age up to 13 years, which can harm the child’s kidneys. This finding is extremely concerning, because there are areas in Rajarata where the fluoride in groundwater is reported to be 5 mg/L or above. This means children of these areas may be consuming more than 14 mg of fluorides per day, which is 6.4 times of the maximum tolerable upper intake of fluoride for a child. This is a very dangerous situation which can lead to serious damage to the kidneys of children. Scientific research investigations related to fluoride and kidneys show that infants and children have an impaired ability to expel absorbed fluoride from the body, and they retain 80-90% of the absorbed fluoride compared to adults (50%). Therefore, the retention of high amount of fluoride absorbed by body/kidneys of children can lead to kidney damage of children living in areas with even 2 mg/L of fluoride in groundwater, as highlighted in above. Consequently, adults whose kidneys were damaged due to fluoride consumption in childhood are at an even greater risk of ending up as CKD patients, if they continued consuming water from the fluoride contaminated sources. Therefore, it is fairly apparent that kidneys of the people living in the areas where high levels of fluoride present in groundwater are likely being exposed to high levels of fluoride that lead to kidney disease, for some as early as from infancy.

Why men in Rajarata more affected than women?

Now that a considerable relationship between CKD and fluoride-contaminated water has been established, one observation leads me to another CKD-related question: what is a possible explanation for men in affected areas in Rajarata more prone to CKD compared to women? Generally, men spend more times in the paddy fields or farms compared to their female counterparts, and dehydration due to constant exposure to the sun make them consume more water, especially in the form of their humble beverage, tea. Tea, actually adds even more fluoride to their system.

Is tea a vehicle for even more fluoride?

Tea, especially low-quality tea, is exceptionally high in fluoride. According to a study conducted in the US, the average fluoride content of the brewed teas is nearly 4 mg/L, which was 3-4 times higher than the average amount of fluoride in tap water in the US. According to the same US DRI charts referred to earlier in this article, the tolerable upper intake levels of fluorides for adults (above 13 years) is 10 mg per day. Let’s consider a scenario where a farmer drinks 4 liters of water (with 2 mg/L fluoride) and 5 cups of tea (1.4 L) on a given day. A quick calculation shows that this farmer consumes 8 mg of fluoride by drinking the 4 liters of water from the water source that has a 2 mg/L fluoride content. Using the US average fluoride content of the brewed tea, another calculation shows that the farmer would be consuming nearly 7 mg (2.8 mg from water that used to brew tea, and 4.2 mg from tealeaves) of fluoride by drinking the 5 cups of tea. This means the average dose of fluoride consumed by the farmer surpasses 15 mg per a day. This amount is 1.5 times the maximum tolerable upper intake of fluoride for an adult. Therefore, even 2 mg/L of fluoride in groundwater can make have harmful effects on farmers living in Rajarata. Similar calculations show that the farmers living in the areas where fluoride content of water is 5 mg/L or above are probably consuming more than 31 mg of fluoride per day, which is 3.1 times the maximum tolerable upper intake of fluoride for an adult, which is chronically toxic to the kidneys.

A link to the Rajarata diet?

A high concentration of fluoride in the soil is also directly linked to high fluoride in the groundwater and surrounding vegetation. The addition of fluoride from diets of crops grown in this soil will also elevate fluoride levels in the body, making people further vulnerable to CKD. Vegetables, pulses and other crops grown in this area likely contain high amounts of fluoride due to high levels of fluoride in the soil and the groundwater. For example, the green leafy vegetable “Thampala” excessively absorbs fluoride from the soil. Therefore, it is highly likely that crops grown in these areas with higher concentrations of fluoride will add even more fluoride to people’s diet, just as with the consumption of tea.

A crisis born three decades ago?

A possible unintended consequence of the Mahaweli River Diversification Programme (herein referred to as the Mahaweli Project) launched in the 1980s comes to mind as the most plausible explanation for my next question: why have all Rajarata CKD cases emerged within the last three decades? The Mahaweli Project that brought a new water source to benefit the Rajarata area caused the groundwater table to elevate. As the Mahaweli Project started to expand into most of the now CKD-stricken areas, the Mahaweli river basin also extended. Due to the flat landscape in the irrigation areas, the supply of extra water led to an increase in water table levels resulting in high salinity levels in groundwater. High salinity in the groundwater means more fluoride and other minerals in groundwater, and most of these saline products make their way into the systems of those who drink groundwater and consume agricultural crops grown in the area. This theory is supported by reports calming that groundwater in the CKD-affected areas have become more saline during the past decades, based on observations made by the people living in the area. Further, scientific reports on gradual but substantial increases in the fluoride content of groundwater in Rajarata further validate this observation. In addition to the rise of the water table, drilling of a large number of tube wells in the region could also be another factor affecting the increase of salinity of well water, including fluoride levels. Aligning with the above, reports on the distribution of fluoride in groundwater in Sri Lanka clearly show that the level of fluoride in groundwater in CKD-prevalent areas is much higher than that of the neighboring farming districts (i.e. 1-3 mg/L). This disparity may probably be due to the absence of major irrigation projects in those neighboring districts during the last two to three decades, thereby keeping the groundwater table at a stable level, which prevents the increase of fluoride and other minerals in the groundwater as well as in the food crops grown in those areas. As high salinity in groundwater indicates more fluoride in groundwater, drinking this groundwater and consuming a locally-grown diet could highly likely be the reason for this relatively newly-detected chronic kidney disease in Rajarata. If it was not for Dr. Tilak Abeyesekera reporting a pattern of this kidney disease in Rajarata, we would not have known for how long this condition had existed, and how many people had perished from the disease.

To summarize all my points above:

There is a high fluoride content in the groundwater in Rajarata, and due to fluoride poisoning, dental and skeletal fluorosis is widespread in the communities.

There is a considerable amount scientific evidence worldwide to prove that there is a direct link between high fluoride levels in drinking water and kidney disease.

It is harder for children to eliminate fluoride from their systems compared to adults, which leads to kidney damage of children living in the areas with high fluoride.

If adults who had kidney damage due to high fluoride in their childhood continue to consume water from the same water source, they are more vulnerable to CKD.

Through consuming more water and tea, people working in farms and engaging in other laborious activities outside for prolonged periods are even more susceptible to additional doses of fluoride entering their system.

The extension of the Mahaweli river basin due to the Mahaweli Project led to the rise in water-table levels, resulting in high salinity levels in groundwater, adding more fluoride and other minerals to groundwater.

All these additional fluorides and other saline products make their way into the systems of the people in Rajarata area, through the drinking water and through diets of locally grown crops.

To conclude, based on the above arguments derived from scientific literature and research, I believe with confidence that the culprit of the so-called “Rajarata Chronic Kidney Disease” in Sri Lanka has to be the excess fluoride in drinking water from the wells and in the local food crops grown in the affected areas. Therefore, I highly recommend that the Sri Lankan Government immediately take action to provide safe drinking water to the people in Rajarata, while educating especially the school children on the possible root causes of the diseases. As a start, for example, nursing mothers should be discouraged from using groundwater for formula preparing or any cooking purposes. I also believe that purified surface water from local tanks fed by Mahaweli river water is much safer than the groundwater in the affected area.

Ranjith W. Dharmaratne (BSc, PhD) is a scientist. This article is based on two recent review articles written by the author that appeared in peer reviewed international journals, Journal of Environment Science and Preventive Medicine (2015) and Human and Experimental Toxicology (2018).