OLDONYOSAMBU, Tanzania (Reuters) — A fast color-changing test that detects fluoride in drinking water could help prevent the crippling bone disease of skeletal fluorosis in developing countries, say UK researchers.
“Fluoride is often added to drinking water, and a little bit is beneficial. It can lead to reduced levels of tooth decay but too much fluoride in drinking water is actively harmful and can lead to a disease called skeletal fluorosis, a devastating, crippling condition whereby bones are attacked by the fluoride,” lead researcher Dr Simon Lewis, from the University of Bath, told Reuters.
Skeletal fluorosis causes crippling deformities of the spine and joints, especially in children whose skeletons are still forming. Adults are also affected.
One sufferer is six-year-old Kurianga, from the Tanzanian town of Oldonyosambu, near the city of Arusha. People there have been found to be drinking water with naturally occurring levels of fluoride more than 60 times the US recommended level.
Kurianga’s legs are badly bent and he is forced to walk with a makeshift stick. He’s currently undergoing corrective surgery in Moshi, but Bath researchers want to prevent future generations suffering from the same condition.
Researcher Carlos López-Alled has developed a molecule that, when added to water, changes color from purple to blue within minutes if fluoride levels are too high. “It gives an unambiguous indication about whether the water has too much fluoride in it or not,” said Lewis.
“It doesn’t require a laboratory or specialist equipment. It doesn’t require a person who’s been highly trained to use any equipment or power supply. It doesn’t even require the user to be literate,” he added.
The technology is in the proof-of-concept stage, but the team hopes to develop non-liquid test strips, similar to litmus paper, that could be used on site to tell locals when their water filters need replacing.
According to Dr Jannis Wenk, “many filters exist already, but after a while they are spent.”
“There’s a certain uncertainty about the period when fluoride is getting past those filters, so these colour metric molecules would give people a cheap way to find out the concentration in the water and tell when it’s time to replace the filter,” Wenk said.
In areas of the developing world, such as Tanzania and parts of India, there are no piped water systems or treatment works, and people drink untreated water from wells. When water passes over certain minerals, it can dissolve fluoride. Fluoride levels in the groundwater vary due to weather events, such as heavy rain.
In addition to spine and limb curvature, skeletal fluorosis causes chronic pain and poor cognitive development in children.
Nasio Trust, a charity devoted to protecting and supporting vulnerable children in East Africa, is working with the University of Bath’s Centre for Sustainable Chemical Technologies and the Water Innovation and Research Centre (WIRC) to test the technology.
Additional partners are being sought to develop the test. The Bath team also plans to adapt the technology to other types of water contaminants, such as mercury and lead.
The research was published in peer-reviewed journal Chemical Communications.
