NEW DELHI: The burning of sugarcane and rice husks may be releasing a toxic substance which is causing a mysterious kidney disease among agricultural workers in India, Sri Lanka, the US and many other countries, according to a study.
An ongoing epidemic of chronic kidney disease has been observed among manual labourers in hot agricultural communities throughout the world, the researchers said.
While heat stress and climate change have contributed to this epidemic, researchers have identified tiny silica particles released from sugarcane ash that can be inhaled or ingested through contaminated drinking water that cause chronic kidney damage.
"To date, there are no studies we are aware of that have identified a toxicant that can cause chronic kidney disease which is actually present in kidney tissues of patients suffering from this unknown disease," said Jared Brown, a professor at the University of Colorado, US, and one of the senior authors of the study.
"These data provide an important clue to the mystery and suggest that in addition to heat stress from climate change, toxicants from sugarcane ash could be contributing to the disease," Brown said.
The team found significantly more silica particles in the kidney tissue of patients with this particular disease compared to patients with other known kidney diseases.
The study suggests the disease could result from exposure to sugarcane ash, which contains amorphous silica nanoparticles.
This process may also be linked to people who work in rice paddies, as the burning of the rice paddies, which is also commonly done, can also lead to the release of silica-containing ash.
"While this data is preliminary, we can determine that the burning of sugarcane may not only be contributing to climate change, but it may have a role in the epidemic that has been affecting agricultural workers," said Richard Johnson, a professor at the University of Colorado and one of the senior authors.
"This disease is identified as one of the first newly recognised diseases resulting specifically from a warming climate. Now we know toxicants are also involved. Hopefully this work will spur efforts to focus on sugarcane burning as a potential risk factor for the development of this mysterious kidney disease in workers and people who live adjacent to sugarcane fields," Johnson added.