China’s Rare Earth Rush Is Poisoning the Mekong — And Southeast Asia Is Paying the Price

Sun Lee

For seventy million people, the Mekong River isn’t scenery. It’s dinner. It’s income. It’s the reason a village exists where it does. Now, for the first time, arsenic has been confirmed in the river’s mainstream sediment not just its tributaries and the trail of toxic mud leads straight back to a mining boom that China created, exported, and continues to profit from.

From Beijing’s Backyard to Myanmar’s Frontier: The story starts with a clean-up but not the kind that helps anyone downstream. When China tightened environmental enforcement on its own rare earth industry, the dirtiest part of the business didn’t disappear. It moved. Mining operations that once scarred hillsides in southern China shifted across the border into Kachin and Shan States in Myanmar, where a 2021 military coup had already shattered central authority and handed resource-rich frontier territory to ethnic armed groups.

The numbers tell the story of just how fast this relocation happened. In Kachin State alone, mining sites jumped from roughly 130 in 2020 to over 370 by the end of 2024. Myanmar’s rare earth exports to China, overwhelmingly the destructive heavy rare earths used in EV motors and wind turbines, more than doubled in the two years after the coup, and 85% of the $4.2 billion in exports recorded between 2017 and 2024 came after the military took over. By 2023, Myanmar was supplying more than 60% of China’s heavy rare earth imports by value output that, tellingly, exceeded China’s own domestic mining quota that year. China didn’t just tolerate this shift. It became structurally dependent on it, while keeping its hands clean of the mess it produces.

Satellite imagery from the U.S.-based Stimson Centre has identified 833 unregulated mines across the Mekong River Basin, with 86 confirmed as rare earth operations using blue tarpaulin leaching ponds, more than half of which opened between 2024 and 2026. Arsenic has now reached the Mekong mainstream itself, with Thai testing in Chiang Mai and Chiang Rai in early 2026 showing levels exceeding safety standards at all 23 monitored sites for the first time. On the Salween River, arsenic readings hit 0.096 mg/L on the main stem and 0.554 mg/L on a tributary, more than 55 times the WHO threshold. The economic damage on Thailand’s Kok River alone was estimated at 1.3 billion baht (about $40 million) by September 2025, with projections surpassing $90 million if left unaddressed. Meanwhile, the Salween basin recorded 127 suspected mining sites between 2016 and 2026, with the sharpest expansion after 2023. Each of these figures represents heavy metals like arsenic, lead, cadmium, and manganese that persist in sediment, move into fish, and accumulate in people’s bodies, contaminating rice, garlic, and edamame that enter the global supply chain at its source.

A Convenient Arrangement for Beijing: Here is what critics of China’s role point to as the uncomfortable core of this crisis: Beijing gets to have it both ways. Its domestic environmental record improves on paper while its factories keep receiving a steady, cut-rate supply of the exact same toxic material just mined 50 miles across the border instead of at home. Chinese companies and buyers deal directly with armed groups like the United Wa State Army and the Kachin Independence Army, financing militias that fund civil war with mining revenue while skirting any accountability for the environmental devastation those mines leave behind. When Kachin fighters seized key rare earth towns in 2024, China’s response wasn’t environmental concern it was a border closure to pressure trade terms, followed by a new pricing deal once exports resumed. The message was clear: keep the minerals flowing; the mud is someone else’s problem.

Beijing also holds enormous leverage as the source of roughly 90% of global rare earth processing capacity, a chokehold it has openly used as a geopolitical weapon restricting exports to pressure Washington, Tokyo, and Brussels in trade disputes. That same dominance means China could, if it chose to, impose environmental standards on the material entering its own refineries. It has not. Regional bodies like the Mekong River Commission have no authority to compel change upstream, and China’s foreign ministry did not respond to press inquiries about the mineral imports fuelling the crisis, according to Mongabay reporting.

The Other Side of the Story: Fairness requires noting the fuller picture. The mines themselves sit inside Myanmar, run by Myanmar-based armed factions and, in some cases, the military junta not the Chinese state directly. Myanmar’s own post-coup collapse, not a Chinese master plan, created the lawless vacuum these operations exploit. Some analysts argue China’s posture reflects economic opportunism and regulatory neglect rather than a deliberate strategy to harm its neighbours, and note that global demand from EV makers to electronics manufacturers worldwide is what makes this mining profitable in the first place.

Whatever the intent, the outcome is the same: a river that feeds Thailand, Laos, Cambodia, and Vietnam is turning toxic, and the profits are flowing north while the poison flows south.