CHIANG RAI – The Governor of Chiang Rai Province has raised the monitoring level for four major waterways after unhealthy arsenic levels appeared in a small set of sample tests on villagers residing along the Kok River. The governor ordered re-testing, set an urgent coordination center, and asked the public not to panic because it could affect tourism.
At 2:30 p.m. on February 25, 2026, Chiang Rai Governor Choochip Pongchai chaired the second 2026 meeting of the committee tracking water quality in the Kok River, Sai River, Ruak River, and the Mekong River.
The meeting took place at the Thammalangka Meeting Room, 3rd floor, Chiang Rai Provincial Hall.
Attendees included Deputy Governor Prasert Chitpleecheep and representatives from Mae Fah Luang University, the Chiang Rai Office of Natural Resources and Environment, the Chiang Rai Provincial Public Health Office, the Chiang Rai Fisheries Office, and other related agencies.
During the meeting, officials shared early research results collected after the flooding situation. The team took samples from a group of 10 people in target areas. The highest arsenic (Arsenic) reading reported was about 1.947 mg/kg. Some cases may be above international standards.
The main risk group includes farmers and people with long-term water contact, especially those exposed for more than 10 years. The report also flagged vulnerable groups, such as children and older adults, particularly those with unusual skin symptoms or numbness.
Researchers caution that the data is still uncertain
The research team said the findings still carry uncertainty because the sample size remains small. In addition, a key confounding factor appeared in the area, pesticide spraying within 24 hours before sample collection, which may affect accuracy.
Meanwhile, overall raw water test results from government agencies at some locations still fall within standard limits.
Governor Choochip directed agencies to move quickly to clarify the situation and prevent wider impacts. The plan includes these steps:
- Confirm the results (top priority)
Mae Fah Luang University’s research team will work with the Pollution Control Department to re-collect samples. This includes environmental samples (water and sediment) and biological samples (urine and hair). Teams must follow SOP standards strictly and share preliminary results within 2 weeks. - Set up a coordination center.
The Provincial Office will lead the creation of a central information hub. The goal is to connect labs with local administration and reduce duplicate work. - Strengthen local laboratory capacity.
The province will push for Mae Fah Luang University and the Regional Medical Sciences Center to serve as key reference labs locally. This should speed up heavy metal testing instead of waiting for central labs. - Clinical surveillance system
Hospitals in the network will collect samples from at-risk groups and students in nearby areas. This will help assess short-term and long-term health effects.
Chiang Rai’s public confidence and tourism
The committee also raised concerns about possible harm to Chiang Rai’s image and tourism. As a result, the governor instructed the Provincial Public Relations Office to produce two types of communication materials, one technical set for specialists and another in simpler formats, such as infographics or animations, for residents and visitors. The focus will be clear guidance on safe and appropriate behavior.
Officials stressed that messaging must stick to scientific evidence. If points remain unclear, they should not be treated as final until reference labs confirm the results. The province wants to avoid unnecessary panic and reduce any impact on the tourism economy.
Over the longer term, Chiang Rai plans to create a risk map to identify possible sources of arsenic. The province will consider agricultural activity, mining, and natural resources. Agencies will continue monitoring for at least 3 years to study potential buildup in the food chain.
The committee will meet again within 2 weeks to review the re-test results and consider budget approval for ongoing work at the coordination center.
