Health Warning Issued for Mae Sai River Water in Chiang Rai
The Department of Health has advised residents in Chiang Rai to avoid using water from the Mae Sai River due to high arsenic levels.
On October 2, 2026, the Thai Department of Health issued a formal warning to residents living near the Mae Sai River in Chiang Rai province. According to reports from Matichon Online, authorities have detected arsenic concentrations reaching 0.28 milligrams per liter, a level that exceeds safety standards.
As a precautionary measure, the department has strongly advised the public to refrain from using water from the river for any activities, including domestic use, until further notice. Arsenic is a toxic substance, and exposure to elevated levels can pose significant health risks to humans and animals.
For residents and travelers currently in the Chiang Rai area, particularly those near the border region, it is essential to follow local government directives and avoid contact with the river water. While the warning is currently in effect, authorities have not yet provided a timeline for when the water quality might return to safe levels. It remains to be confirmed how long the contamination will persist and what specific environmental factors contributed to this spike in arsenic levels. Local officials are expected to conduct further testing and provide updates as the situation develops. Residents are encouraged to monitor official announcements from the Department of Health for the latest safety guidance.
