Edinburgh University scientists and students have devised a simple test to detect the presence of arsenic in untreated water supplies.
Up to 35 million Bangladeshis are drinking arsenic-contaminated water
Arsenic poisoning is thought to affect up to 100 million people worldwide, with about one million people believed to have developed cancer as a result.
Nine students from the university's School of Biological Sciences developed the colour-coded test system.
The university said it hoped to secure funding to develop the technology.
The test, which would cost around 50p to manufacture, uses a modified version of E. coli bacteria.
When the bacteria detect arsenic, they release acid.
The water turns red if there is a major contamination, it stays the same with a small arsenic presence and turns blue if there is no contamination.
The World Health Organization has estimated that up to 35 million people in Bangladesh alone are drinking arsenic-contaminated water.