Arsenic Contamination Warning Issued for Mae Sai River
Authorities have warned residents in five sub-districts of Mae Sai, Chiang Rai, to avoid using river water due to high levels of arsenic and heavy metals.
On October 8, 2026, the Department of Disease Control issued an urgent health advisory for residents in five sub-districts of Mae Sai, Chiang Rai: Mae Sai, Pong Pha, Si Mueang Chum, Wiang Phang Kham, and Ko Chang. Testing has identified arsenic and heavy metal concentrations exceeding safety standards in the Mae Sai River.
Dr. Montien Khanasawat, Director-General of the Department of Disease Control, stated that arsenic exposure through contaminated water or food can pose significant long-term health risks. Consequently, officials have ordered a suspension of the use of river water for drinking, cooking, or the production of ice and beverages. Residents are also advised to avoid catching or consuming aquatic life from the river.
This warning is particularly critical for vulnerable groups, including children, pregnant women, the elderly, individuals with underlying health conditions, and those whose livelihoods depend on the river. Residents are urged to use alternative clean water sources and to monitor official provincial announcements for further updates. While the immediate directive is to avoid contact with the water, the full extent of the contamination and the timeline for remediation remain to be confirmed by local authorities. Travelers and residents in the area should strictly adhere to these guidelines to minimize health risks.
