Is there a connection between kidney disease and chemical fertiliser?

  • A group of agriculture experts aim to shift the narrative

By Sumudu Chamara

The Government’s initiative to stop the use of chemical fertiliser and create an agriculture sector that depends on organic fertiliser keeps facing challenges, and the Government is trying to stick to its plan irrespective of these challenges.

Even though it was only farmers’ groups/activists, politicians, and a handful of academics that conveyed strong displeasure about the practicality of the said plan, the opposition has now taken a new turn with professionals and academics in the agriculture sectors coming forward.

Last week, the Agriculture Professionals’ Front, a group comprising 14 trade unions and organisations associated with the agriculture industry, claimed that the Government’s plan to go organic, or banning chemical fertiliser and establishing an organic fertiliser-based agriculture, is based on two myths. The group strongly opposed the widespread idea that chemical fertiliser is causing the controversial chronic kidney disease (CKD).

According to them, the two myths that are said to have led to the Government’s decision are firstly, that chemical fertiliser is poison and secondly, that chemical fertiliser has led to the CKD largely found in the Rajarata areas in the Polonnaruwa District.

Speaking at a press briefing, Federation of University Teachers’ Associations (FUTA) Agriculture Subcommittee Convenor and Ruhuna University Senior Lecturer K.K.I.U. Anura Kumara, a member of the said coalition, claimed that Sri Lanka’s agriculture is currently battling the largest crisis it has faced since independence, and that this crisis has been created on the basis of the aforesaid myths. 

The press briefing was attended by a number of groups representing the agriculture sector, including the Research Scientists’ Association of the Department of Agriculture, the Agriculture Graduates’ Association of the Sri Lanka Agriculture Service, the Tea Inspector/Extension Officers’ (Technical) Union, the All-Island Agriculture Instructors’ Trade Union Federation, the Agriculture Research Assistant Officers’ Association, the Scientific Service Researchers’ Association, the Sri Lanka Scientific Service Officers’ Association, the Ceylon Scientific Service Researchers’ Association of the Export Agriculture Department, the All-Island Livestock Development Instructors’ Trade Union, the Coconut Cultivation Board Extension Officers’ Union, the Export Agriculture Extension Officers’ Union, the Sri Lanka Agriculture Service Officers’ Islandwide Association, and the Sri Lanka Rubber Inspectors’ Association were also present at the press conference.

Kumara pointed out the questionable nature of several opinions that support the claim that chemical fertiliser is causing CKD. Adding that CKD is found in the Mullaitivu District, a district which, according to him, did not have access to chemical fertiliser for 30 years due to the civil war, he said that more chemical fertiliser is used for vegetable cultivation in the upcountry region such as in the Nuwara Eliya District than in the Polonnaruwa District.

Adding that farmers in the Nuwara Eliya District do not face the issue of CKD, Kumara said that even though one may feel that chemical fertiliser in the water flows downhill through the rivers to reach the Polonnaruwa District, resulting in more CKD cases in Polonnaruwa District, it has been found that most of those who suffer from CKD use water from underground wells as opposed to rivers.

“Sri Lanka has created this myth that our farmers who have ensured the country’s food security for generations are feeding poison to us. How can we say that CKD is caused due to chemical fertilisers when a single scientific study regarding the alleged correlation has still not been done in the country?” Kumara questioned.

According to studies, even though CKD/CKDu has existed for decades, during the past two decades, there has been a rapid increase in the number of KCD/CKDu cases. In addition, in some cases, not showing symptoms at all, or showing symptoms which are also signs of other diseases, has been challenging. When it comes to CKDu, not being able to ascertain suspected risk factors, and in some cases, difficulties in finding evidence and different CKDu-affected areas and populations focusing on different risk factors, have also been challenging.

According to the UK’s National Health Services (NHS), CKD is a long-term condition where the kidneys do not work as well as they should.

It is a common condition which is often associated with getting older, and can affect anyone. However, according to the NHS, it is more common in people who are Black or of South Asian origin. Even though CKD can get worse over time and can eventually cause the kidneys to stop working altogether, it is not common, and many people with CKD are able to live long lives with the condition.

According to the NHS, in the early stages of CKD, symptoms may not be visible, and in that stage, a diagnosis is only possible through a blood or urine test (for another reason), and the results of such tests may show signs of a possible problem with the kidneys.

However, as the disease worsens, CKD may show certain symptoms such as tiredness, swollen ankles, feet or hands, shortness of breath, feeling sick, and blood in urine.

There may be a number of reasons for CKD, including high blood pressure, diabetes, high cholesterol, and long-term, regular use of certain medicines.

As has been stated concerning the Sri Lanka’s context, several kidney-related conditions/diseases can also cause CKD, including kidney infections, glomerulonephritis (kidney inflammation), polycystic kidney disease (an inherited condition where growths called cysts develop in the kidneys), and blockage in the flow of urine (due to reasons such as kidney stones or an enlarged prostate).

CKD only progresses to kidney failure in around one in 50 people with the condition, according to the NHS.

Sri Lanka’s situation is mostly associated with CKD of unknown aetiology, or CKDu, which is a type of CKD, which, according to the International Society of Nephrology (ISN), mainly affects marginalised agricultural communities in various areas of the world, and it has been noted that most of the time, large number of people from the same area shows signs of this disease, some of which may be extremely serious or even deadly. The ISN said that most patients affected by CKDu are males between the ages of 20 and 60 who often live in rural or agricultural settings and may be exposed to extreme working conditions.

The ISN said that although CKDu is mainly reported in Sri Lanka and Central America, more hotspots are being identified. It added that in Central America, CKDu is also/predominantly referred to as “Mesoamerican Nephropathy”.

Initial surveys conducted in Central America had shown that up to 20-30% of adults in “endemic communities” show a high prevalence of decreased kidney function of unknown origin, possibly of environmental or occupational origin. In certain countries in Latin America, the issue has become a severe public health crisis. 

The ISN further said that hospitalisations for CKD in El Salvador increased by 50% between 2005 and 2012, making CKD the leading cause of hospitalisation in the country, and that nearly 1,500 of these hospitalised patients were under 19 years old (out of a total 40,000 hospitalised patients of all ages during the same period).

With regard to Sri Lanka’s situation, according to available data and studies conducted by local researchers, CKDu is mostly prevalent in the North Central Province, which has two districts, i.e. Anuradhapura and Polonnaruwa. However, cases have been reported from the Central, North Western, and Eastern Provinces. In 2016, Annual Health Statistics of Sri Lanka listed CKD as the leading cause of hospital deaths in the Anuradhapura and Polonnaruwa Districts.

Concerning CKDu in Sri Lanka, a study, titled “CKDu in Sri Lanka: A Multilevel Clinical Case Definition for Surveillance and Epidemiological Studies”, conducted by Eranga S. Wijewickrama and Saroj Jayasinghe of the Department of Clinical Medicine, Faculty of Medicine of the University of Colombo; Nalika Gunawardena of the WHO’s Sri Lanka Country Office; and Chula Herath of the Department of Nephrology and Transplantation of the Sri Jayewardenepura General Hospital; said: “The disease (CKDu) is not associated with typical risk factors for CKD such as diabetes or hypertension, and it primarily affects young and middle-aged individuals belonging to low socioeconomic groups living in agricultural communities. It is progressive, is asymptomatic until the late stages, and the characteristic histopathology on renal biopsy is a chronic tubulointerstitial disease with secondary glomerulosclerosis.”

Sri Lanka’s Health Ministry, in 2016, developed a three-level epidemiological case definition to identify CKDu in Sri Lanka. After a series of discussions participated by medical experts, a final clinical case definition (based on three tiers of diagnosis) was introduced. The three levels are “suspected CKDu (relevant for the primary care level, probable CKDu (for epidemiologic surveillance), and confirmed CKDu (for clinical diagnosis)”.

Even though Kumara claimed that no scientific study has been conducted in the country to look into the correlation between chemical fertiliser and CKD, several studies have tried to look into the risk factors leading to CKDu in Sri Lanka. Some of these studies, conducted by health professionals and academics, also focused on the relationship between CKD/CKDu and certain chemicals released to the environment, especially soil and water, by chemical fertiliser, both in Sri Lanka and in other countries. However, according to researchers, unlike in the case of CKD, identifying what specific factors lead to CKDu has been challenging, which has led experts in the field to refer to CKDu as a “mysterious” disease.

A study titled “A comparative review: CKDu research conducted in Latin America versus Asia”, conducted by researchers Jennifer Hoponick Redmon, Keith E. Levine, Jill Lebov, James Harrington, and A.J. Kondash, said that while CKDu-related research in Asia mainly focused on drinking water, heavy metals, and agrochemical product usage as potential risk factors, research about the same in Latin America focused mostly on heat stress/dehydration and agrochemical product usage as potential CKDu risk factors.

Several studies – i.e. “Assessment of groundwater quality in CKDu affected areas of Sri Lanka: Implications for drinking water treatment” conducted by Titus Cooray, Yuansong Wei, Hui Zhong, Libing Zheng, Sujithra K. Weragoda, and Rohan Weerasooriya; “Chronic kidney disease of unknown aetiology and the effect of multiple-ion interactions”, conducted by M.W.C. Dharma-wardana; and “Fluoride in drinking water and diet: The causative factor of chronic kidney diseases in the North Central Province of Sri Lanka”, conducted by Ranjith W. Dharmaratne – have discussed that drinking water in the dry region of Sri Lanka contains high calcium levels, elevated fluoride concentrations, salinity, and dissolved organic carbon, and suggest that the interaction of magnesium and fluoride are potentially nephrotoxic (can cause a rapid deterioration in kidney function).

One geochemical study, titled “Geochemical and isotopic evidences from groundwater and surface water for understanding of natural contamination in CKDu endemic zones in Sri Lanka”, conducted by E. Edirisinghe, H. Manthrithilake, H. Pitawala, H.A. Dharmagunawardane, and R.L. Wijayawardane, had found that in regions where surface water recharged groundwater was commonly consumed, there was a low incidence of CKDu, while in regions where groundwater followed natural flow paths or had stagnant groundwater had increased incidence of CKDu, pointing to a potential geochemical source of contamination.

According to another study, titled “Deleterious Role of Trace Elements – Silica and Lead in the Development of CKD”, conducted by Starlaine Mascarenhas, Srikanth Mutnuri, and Anasuya Ganguly, had found that trace levels of lead and high silicon concentrations in Indian groundwater, which led researchers to examine the potential cytotoxic risks of these chemicals, and the resulting study had shown that long-term exposure to both lead and silica at concentrations comparable to those found in the groundwater were found to be cytotoxic (the quality of being toxic to cells) in in-vitro cytotoxicity-assays (aimed at measuring loss of some cellular or intercellular structure and/or functions, including lethal cytotoxicity) on human-kidney-cell-lines.

According to “End-Stage Renal Disease Among Patients in a Referral Hospital in El Salvador”, conducted by Ramón García Trabanino, Raúl Aguilar, Carlos Reyes Silva, Manuel Ortiz Mercado, and Ricardo Leiva Merino, and “Pesticide Exposures and Chronic Kidney Disease of Unknown Aetiology: An Epidemiologic Review”, conducted by Mathieu Valcke, Marie-Eve Levasseur, Agnes Soares da Silva, and Catharina Wesseling, even though exposure to pesticides has been implicated in the development of CKDu, because of the cross-sectional nature of the studies and the widespread use of many nephrotoxic pesticides across the globe, it is difficult to attribute CKDu to pesticide exposure alone.

Moreover, exposure to glyphosate, a weed killer that has been banned in many EU countries due to concerns about linkages to cancer, has been proposed as contributing to the development of CKDu, especially with hard water (water that has high mineral content), according to “Chronic Interstitial Nephritis in Agricultural Communities (CINAC) in Sri Lanka”, conducted by Channa Jayasumana, and “Drinking Well Water and Occupational Exposure to Herbicides is Associated with CKD”, conducted by Jayasumana, Priyani Paranagama, Suneth Agampodi, Chinthaka Wijewardane, Sarath Gunatilake and Sisira Siribaddana. 

Further, several studies suggest that pesticides may contribute to the development of CKDu in both Nicaragua and Sri Lanka.

Although several international and local studies suggest that phosphate fertiliser may be a source of arsenic in CKDu-affected areas, whether and to what degree they contribute to CKDu has not been adequately substantiated.

The analysis between Latin America and Asia pointed out the importance of harmonising study designs, adding that even though there have been few concerted efforts to consolidate knowledge and apply a consistent protocol to multiple CKDu studies, research outcomes across regions are difficult to compare without standardising the research design itself. 

“Rather than focusing on a subset of individual risk factors in local communities, research with a harmonised study design to evaluate all potential risk factors across global commonalities is critically needed,” it added.

The issue of CKD/CKDu has been affecting Sri Lanka for at least three decades, according to local researchers, and the prevalence of it has been on the rise. Although the studies that have attempted to deduce whether there is a link between CKDu and chemical fertiliser have been extremely diverse, some of the chemicals chemical fertilisers release to the environment when used have been identified to cause various diseases. However, the question whether chemical fertiliser can cause CKDu (when used as a fertiliser) has received mixed responses, and a great deal of more research needs to be done.

As one study suggested, to identify the issue properly, there needs to be more collaborative efforts between nations, and perhaps that needs more attention from the authorities.