Over 2,400 unregulated mines across Southeast Asia are contaminating vital river systems with toxic chemicals, threatening millions of people and global food supplies, according to a landmark study.
Key Takeaways
- 2,400+ potentially polluting mines identified across mainland Southeast Asia
- Toxic chemicals including cyanide and mercury entering Mekong, Salween, and Irrawaddy rivers
- 70+ million people dependent on Mekong River face health risks
- China-backed rare earth mining in Myanmar driving contamination
For 59-year-old farmer Tip Kamlue, the Kok River in northern Thailand was life itself—until authorities warned against using its contaminated waters this April. “It’s like half of me has died,” said Tip, who now relies on groundwater for her crops.
Unprecedented Scale of Mining Pollution
The US-based Stimson Center’s comprehensive study reveals alarming mining activity across the region. Researchers identified 366 alluvial mining sites, 359 heap leach sites, and 77 rare earth mines draining into the Mekong basin alone.
“The scale is something that’s striking to me,” said Brian Eyler, senior fellow at Stimson. He noted that numerous tributaries of major rivers like the Mekong are likely highly contaminated.
The Mekong, Asia’s third-largest river, supports over 70 million people and global exports of shrimp, rice, and fish. “There is not a major supermarket in the US that doesn’t have products from the Mekong Basin,” Eyler emphasized.
Toxic Chemicals Threatening Health
Unregulated mining releases deadly substances including:
- Cyanide and mercury from gold mining
- Ammonium sulphate from rare earth extraction
- Arsenic and heavy metals
Eyler attributed the crisis to weak governance: “Because so much of the Mekong Basin is essentially ungoverned by national laws and sensible regulations, the basin is unfortunately ripe for this kind of unregulated activity.”
China-Backed Mining Driving Contamination
New rare earth mines in eastern Myanmar, backed by Chinese operations, have raised particular concerns about downstream pollution along the Kok River.
Thai researcher Tanapon Phenrat confirmed testing shows arsenic alongside heavy rare earths like dysprosium and terbium in Kok River samples. “It has only been two years since the rise of rare earth and gold mining in Myanmar at the Kok River’s source,” he warned, predicting sharp contamination increases unless mining stops.
Myanmar has become one of the world’s largest producers of heavy rare earths since the 2021 military takeover. These critical minerals power wind turbines, electric vehicles, and defense systems, with China maintaining near-total control over processing.
Regional Response and Local Desperation
Thailand has established three task forces to address the crisis, focusing on international cooperation, health monitoring, and securing alternative water supplies.
Meanwhile, in northern Tha Ton, signs demand closure of upriver mines. Farmer Tip Kamlue voices the community’s plea: “I just want the Kok River to be the way it used to be—where we could eat from it, bathe in it, play in it, and use it for farming. I hope someone will help make that happen.”



