Toxic tide on Kok River
Pollution from a surge in rare‑earth mining in Myanmar is fouling the Kok River and hurting fishing, farming and tourism in Thai communities downstream. The Straits Times report says the environmental costs of extraction on Myanmar’s side are being externalised onto poorer river communities across the border. (straitstimes.com)
The Kok River now carries arsenic and mining waste from Myanmar into northern Thailand, where villagers say fishing, farming and tourism have all been hit. (straitstimes.com) Thai authorities began testing after residents in Chiang Rai complained in March 2025 that the river had turned unusually murky in the dry season. By May 2025, the Chiang Rai governor had told agencies to warn people not to use water from the Kok and Sai rivers. (transbordernews.in.th) (chiangraitimes.com) Thailand’s Pollution Control Department said a third round of tests in May 2025 found arsenic above the 0.010 milligrams-per-litre standard at 11 of 15 Kok River sites. The same testing cycle found arsenic above the standard at every site checked on the Sai and Mekong rivers. (nationthailand.com) (thailandtribune.com) The river matters beyond one border district because the Kok rises in Myanmar, crosses into Thailand and then flows into the Mekong. In July 2025, the Mekong River Commission said four of five Kok River sampling sites it assessed had arsenic concentrations above the commission’s guideline. (mrcmekong.org) Rare earths are a group of metals used in magnets for electric vehicles, wind turbines and electronics, and the ore is often extracted by washing chemicals through soft clay deposits. That process can leave behind acidic wastewater and heavy metals if pits and ponds are poorly contained. (stimson.org) (ispmyanmar.com) Researchers and rights groups say mining expanded fast in Myanmar after the February 2021 military coup weakened oversight in conflict areas. ISP-Myanmar said Myanmar exported more than United States dollars 3.6 billion in rare earth minerals in 2021-2024, and more than United States dollars 4 billion in 2017-2024 overall. (ispmyanmar.com) China sits at the center of that supply chain because it processes most rare earths and buys heavily from Myanmar. Chinese customs data cited by Global Times showed Myanmar supplied 31,000 tons of rare-earth oxides to China in January-September 2024, or 74.9 percent of China’s oxide imports in that period. (globaltimes.cn) (cnbc.com) The mining footprint has also spread south and east toward rivers that feed Thailand. Stimson Center-backed satellite analysis cited by Business & Human Rights Resource Centre said more than 500 rare earth sites were operating across Myanmar’s northern river basins by late 2025, including dozens opened in 2025. (business-humanrights.org) Some investigators have tied the Kok contamination to militia-held parts of Shan State. The Diplomat reported that gold and rare earth mining zones in southern Shan State are under the control of the United Shan Wa Army, while Shan Human Rights Foundation later said Chinese state-backed operators had expanded rare earth and gold mining along the Kok in eastern Shan State. (thediplomat.com) (nationthailand.com) Thai officials have pushed for talks with Myanmar and China, but local reporting said those efforts had produced requests for cooperation rather than binding action. Along the Kok, that has left downstream communities waiting while the river that once drew tourists and fed families remains under warning. (khaosodenglish.com) (straitstimes.com)
