Southeast Asia’s rivers, people at risk from toxic mines: study
ENVIRONMENT – POLLUTION
25 NOVEMBER 2025
- In April 2025, Thailand authorities warned residents to stop using the Kok’s water because of concerns over contamination.
- Kok River flows down from neighbouring Myanmar before joining with the Mekong River that cuts through Southeast Asia.
- Across mainland Southeast Asia, more than 2,400 mines — many of them illegal and unregulated — could be releasing deadly chemicals such as cyanide and mercury into river water, according to research from the U.S.-based Stimson Center think tank.
- Scores of tributaries of major rivers, like the Mekong, the Salween and the Irrawaddy are probably highly contaminated.
- The potentially polluting mines in mainland Southeast Asia include alluvial mines, heap leach sites and rare earth mines draining into the Mekong basin.
- Most alluvial mining sites are gold mines, though some also extract tin and silver.
- Heap leach mining sites include those for gold, nickel, copper, and manganese extraction.
- The Mekong is Asia’s third-largest river and supports the livelihood of more than 70 million people as well as the global export of farm and fisheries products.
- The toxic chemicals released through unregulated rare earths mining include ammonium sulphate, and sodium cyanide and mercury that are used for two different types of gold mining.
- The emergence of new China-backed rare earth mines in eastern Myanmar had set off concerns among researchers.
- Myanmar, which erupted in conflict after the military seized power in 2021, is one of the world’s largest producers of heavy rare earths, critical minerals infused into magnets that power the likes of wind turbines, electric vehicles and defence systems.
- From mining sites in Myanmar, the raw material is transported for processing to China, which has a near-monopoly over production of these vital magnets, with Beijing deploying rare earths as leverage in its tariff war with the U.S.
