CHIANG RAI — Besides the Kok River, which faces pollution problems from mining in Myanmar requiring international cooperation to resolve, the Sai River – another major waterway – is now becoming an issue with heavy metal contamination being detected.

A group of local residents and civil society organizations raised concerns during a meeting on transboundary pollution affecting the Kok, Sai, Ruak, and Mekong Rivers.

The gathering, under the banner “Shut Down the Upstream Sai River Mine Before It’s Too Late,” brought together around 50 participants at the Wiang Phang Kham Subdistrict Municipality meeting room in Mae Sai District, Chiang Rai, on Thursday.

Warns of Four-River Contamination

Dr Suebsakul Kittanukorn, a lecturer at Mae Fah Luang University, explained that the government is currently only focusing on the arsenic pollution of the Kok River, but the problem has actually spread to four rivers.

“Today, the water in Mae Sai is toxic,” he said. “The government only talks about fighting flooding. We urgently need contamination testing, clear health guidelines for residents and protocols for officials entering flooded areas. Local authorities and clinics need to check who has developed skin rashes after exposure. People should not come into direct contact with the water, but this is difficult to avoid during floods. We need practical guidance. This flood water may contain heavy metals, is it toxic or not?”

Dr. Suebsakul emphasized that the current situation poses a global environmental risk. Satellite images show a rare earth mine in the upper reaches of the river, and China, the world’s largest producer of rare earths, plays a central role. He called on all local authorities to carry out tests.

In Mae Sai in particular, tests have revealed dangerous levels of lead. The Shan State Human Rights Foundation has mapped the mine sites and they are visible on Google Earth.

“Our Raw Water Sources Are Vulnerable”

“Who produces these minerals? Who imports them? Where are they shipped to? Our water supply system is vulnerable, especially in Mae Sai and the neighbourhood. When there is flooding, water production has to be stopped. Our raw water sources are vulnerable. And only one water and sediment test has been conducted in the Sai River,” he added.

A local farmer said that the irrigation channels fed by the Sai spread water over vast arable land. “If the Sai river is contaminated, can we block its flow into the irrigation canals to delay or reduce the formation of residues?” he asked.

Jaroon Barameechai, former president of the Mae Sai Elderly Association, said his house is near a mining area. “The mud from the floods in 2025 is still not gone. Will we get test kits for heavy metals so we can check our wells and our home-grown vegetables? We want to know and protect ourselves.”

Residents Fear Cancer Risk from Daily Water Use

Bundit Phanphalakorn, head of the Wiang Phang Kham community disaster relief centre, said the community uses Sai River water for daily use, including drinking and brushing teeth. He asked about heavy metal residues and future cancer risks. On May 24, he said he helped Tam Phachom residents clean their homes after a flood. Afterwards, he developed a rash on both hands that has not healed to this day.

He added: “Anyone helping the flood victims near the contaminated Sai river must wear a full protective suit, hazmat gear, gloves or even a spacesuit. You have to be brave. The local people don’t even have enough information about how these toxins accumulate in the body. We are now living with the future threat of cancer. Where is the “safety” in our lives? Over 40,000 people depend on this water supply: they are all at risk. If the people of Mae Sai don’t protect their own river, who will?”

Stop Illegal Mining Before It’s Too Late

Thanawat Puangrangsri, a resident of Sai Lom Joy village, said that floods used to be rare. They did not occur every year, and when they did, they disappeared quickly. But now floods are frequent and the water is murky and strange. This is because mining is being carried out upstream. Dredging the estuary will not solve the problem. The soil washed downstream is overwhelming. It is this mining upstream that is really causing us problems.

Pianporn Deetes, secretary-general of the Community Development and Highland Areas Foundation (CDHA), said the pollution of the Kok, Sai, Ruak and Mekong rivers was a serious transboundary problem.

“People want solutions that address the root causes. Illegal open-cast mining at the source of the river, where millions of people depend on clean water, must be stopped immediately. Today we see the water, but we can’t use it. And for the Sai River, the government still has no clear plan on how to tackle heavy metal pollution.”

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