Monsanto’s Herbicide Might Be Killing Farmers

A widespread renal disorder, referred to as Chronic Kidney Disease of Unknown etiology (CKDu), has been afflicting agricultural rice paddy workers in Sri Lanka since the mid-1990s. This particular type of renal disease is distinct from the known CKD in that its victims remain asymptomatic and do not suffer from diabetes mellitus, hypertension, or glomerular nephritis; indicators normally associated with the CKD. Research groups, including the World Health Organization, have worked to determine the cause of this CKDu endemic. And while arsenic (As), cadmium (Cd), and pesticides are noted to be the disease’s main contributing factors, scientific consensus on the disease’s etiology has not been reached.

An online Vice News article reports a probable cause of CKDu based upon one study’s hypothesis recently published by the International Journal of Environmental Research and Public Health. Researchers Channa Jayasumana, Sarath Gunatilake, and Priyantha Senanayake have hypothesized that glyphosate, more commonly known under its Monsanto brand name, “Roundup,” is the primary culprit. 

However, glyphosate does not work alone. A number of other important factors, notably water hardness and nephrotoxic metals, such as arsenic, compound the chemical’s deleterious effects. For instance, in regions of Sri Lanka where water hardness is categorized as “hard” or “very hard,” prevalence of CKDu is much greater, as is illustrated in Figure 1:

Figure 1. Geographical distribution of patients with CKDu and ground water hardness in Sri Lanka. Ground water hardness data- with the courtesy of Water Resources Board of Sri Lanka.  

Glyphosate is the most widely used herbicide both in Sri Lanka, and the world. Originally patented by Stauffer Chemical Company as a descaling agent to clean calcium and other minerals from pipes, glyphosate is a well known metal binder. Rice paddy soil in CKDu endemic regions are high in metals, including Ca, Mg, Fe, Cr, Ni, and Co, which thereby combine readily to glyphosate. Exacerbating the problem is that TSP (triple super phosphate), a fertilizer which has been demonstrated to contain a significant amount of heavy metals, such as Cd, Cr, Ni, and Pb, is applied to the rice paddies within two weeks after glyphosate spraying. 

Both CKDu patients and non-CKDu afflicted individuals have been shown to have toxic levels of arsenic in their biological samples. Arsenic toxicity, primarily from the use of contaminated agrochemicals, in combination with Ca and Mg found in hard water, is what ultimately leads to significant kidney damage and CKD. While the source of the arsenic remains a contentious point, “Compound X,” dubbed by the researchers to be the unknown agrochemical at the root of the CKDu epidemic, matches the same characteristics as glyphosate. Furthermore, in the Northern Province of Sri Lanka, where ground water is particularly high but there are relatively low use of agrochemicals due to governmental prohibitions, CKDu is not prevalent.

On the whole, Vice News contributor, Neha Shastry, does a fair job representing the International Journal of Environmental Research and Public Health study. However, she does places a slightly greater attention on the role of glyphosate alone in CKDu, rather than the combined effect of the agrochemical with hard water and the nephrotoxic metals. And while Shastry omits some other pertinent information, including: glyphosate’s metal binding properties, its distinction from known CKD, the use of contaminated TSP, the statistically significant correlation between water hardness and CKDu in afflicted regions, and a greater emphasis on the absence of the disease prior to the mid-1990s, she does capture the report’s essence and relays it to a main stream audience without the use of flowery language or exaggerated claims. Lastly, Shastry’s inclusion of Monsanto’s response, as well as noting the EPA’s recent approval to raise glyphosate residue concentrations in produce, provides an interesting 360-degree view of the issue. However, I would argue that the EPA's latest ruling may or may not be relevant in this article's regard, as additional information surrounding the approval is not detailed.