Over the past twenty years, thousands of people in rural Sri Lanka have faced a puzzling epidemic of kidney failure, widely referred to as CKDu. In tandem, unusual cases of kidney disease emerged among tropical farming communities worldwide.
Field studies of wells supplying drinking water were conducted in Sri Lankan communities by researchers from Duke University. The possible culprit points to glyphosate, the active ingredient in Roundup. Glyphosate is the most widely used herbicide globally and is prevalent in Spain as well.
The findings were published in Environmental Science & Technology Letters last September.
Roundup is a glyphosate based herbicide used to control weeds and pests. It tends to degrade in the environment within a few days to weeks, a factor that has kept its regulatory oversight relatively light in many public health systems.
Analyses were performed across numerous drinking water wells, led by researchers such as Jake Ulrich.
However, when glyphosate meets certain metal ions like magnesium and calcium that make water hard, glyphosate can form metal ion complexes. These compounds can persist in water for as long as seven years and in soil for as long as twenty-two years, according to researchers.
“This chemical was long believed to break down quickly, but it appears to linger much longer in some conditions. When it binds with hard water, it forms more compounds than anticipated”, said Nishad Jayasundara, a Duke University environment professor. “We must consider how glyphosate interacts with other elements and what happens when it enters the body as a complex.”
Up to 10 percent of children are affected
In certain agricultural regions of Sri Lanka, the combination of a dry climate and underlying geology creates perfect conditions for hard water. CKDu has reached epidemic levels in these zones, with recent observations showing signs of early kidney damage in up to 10 percent of children aged five to eleven.
Jayasundara, originally from Sri Lanka, suspected glyphosate may play a key role in this disease. Sri Lanka has banned the herbicide in response to the water hardness issue. To test this idea, Jayasundara joined forces with two chemists, Lee Ferguson and Jake Ulrich, along with Mangala De Silva, a professor at the University of Ruhuna. The team sampled more than 200 wells across four Sri Lankan regions.
Ferguson laboratory work at Duke uses high resolution tandem mass spectrometry to detect contaminants, even at trace levels, by weighing their molecules. This technique provides precise identification and quantification of substances in a water system.
Up to 44% higher levels
Using this approach, researchers found significantly higher glyphosate levels in 44 percent of wells from the affected areas, compared with only 8 percent outside these regions.
“In this case the focus was drinking water, but other exposure routes may be significant too”, Ferguson noted. Direct contact with agricultural workers applying pesticides or exposure through food and dust are potential pathways. He called for more studies on how people may encounter these substances and how they travel through the environment and into the body.
Ulrich’s work also revealed elevated fluoride and vanadium levels in the drinking water of communities with high CKDu rates. These pollutants, alone or in combination, deserve closer scrutiny given their link to kidney damage.
Researchers agree that more attention should be paid to the health impact of each contaminant and how they interact in real-world settings. Experts see this study as a warning about glyphosate exposure in hard water areas and its possible connection to CKDu.
There is also a parallel concern about pollutants with persistent behavior, such as perfluorinated substances or PFAS, often called forever chemicals due to their long-lasting presence in the environment. The properties of glyphosate share similarities with these compounds in terms of persistence in water that is hard or highly mineralized.
The team references a body of work with the DOI 10.1021/acs.estlett.3c00504 as part of this ongoing inquiry.
Finally, the researchers emphasize the need for additional information about exposure routes and interactions with other contaminants to better understand risk and guide public health responses in rural water supplies.