When water flows over certain naturally occurring minerals in soil or rocks, it may dissolve fluoride. As a result, high concentrations of naturally occurring fluoride are found in some drinking water sources in certain parts of China, East Africa, India and North America.

In developed countries, fluoride concentrations in drinking water are checked and controlled by water treatment facilities before it is piped to households. However, in undeveloped countries where water treatment and distribution networks are lacking, people depend on untreated well water, which very often is tainted with fluoride at levels that are deemed unsafe.

Fluoride concentrations in groundwater tend to fluctuate widely according to the weather, with higher concentrations typically occurring after periods of high rainfall.

Now, a team of researchers from the Centre for Sustainable Chemical Technologies at the University of Bath, together with scientists from the university's Innovation and Research Centre (WIRC), have developed a quick, simple and selective color-changing test that is able to detect high levels of fluoride in drinking water. The researchers hope to develop the color-change test into a low-cost disposable test strip that is accessible, accurate and easy for anyone to use. The team believe that in the future this could make a real difference to the health and welfare of people who are routinely exposed to fluoride.

The Bath research team have partnered with the Nasio Trust — an NGO that protects and supports at risk children in Eastern Africa — to develop their water testing system to make it easier to use on the ground.

"For decades, people living in Oldonyosambu area of Arusha Tanzania East Africa, have been drinking water with naturally occurring levels of fluoride that can reach over sixty times the US recommended level. This has had a severe impact on the lives of people in this poor community, causing crippling skeletal fluorosis, chronic pain and poor cognitive development in children," said Director of the Nasio Trust, Nancy Hunt, who hopes that the newly formed partnership will help them identify water sources with high fluoride levels so that they can take measures to make the water safe for people of Oldonyosambu to drink, and in so doing, ultimately improve the long-term health outlook of this community.

The researchers are also seeking additional partners who can assist them with taking this technology to the next level and help develop the test. The team also plan to adapt the technology so that it can be used to detect other hazardous water contaminants such as cadmium, lead and mercury in the future.

A Berkey water filter equipped with the fluoride filters is able to remove fluoride from the water.

Journal Reference

Carlos M. López-Alled, Adrian Sanchez-Fernandez, Karen J. Edler, Adam C. Sedgwick, Steven D. Bull, Claire L. McMullin, Gabriele Kociok-Köhn, Tony D. James, Jannis Wenk and Simon E. Lewis "Azulene–boronate esters: colorimetric indicators for fluoride in drinking water", Chemical Communications, (2017) DOI: 10.1039/c7cc07416f