UN Observers Visit Contaminated Rivers, Hear from Affected Communities
UN observers documented severe heavy metal contamination in northern Thai river systems during field visits to the Kok, Sai, Ruak, and Mekong basins in late July, with farmers and fishers reporting declining yields, health concerns, and eco
Between July 28 and August 2, 2025, civil society networks including the ETOs Watch Coalition, Community Information Center Foundation, Community and Highland Development Foundation (CDHF), Mekong River Freedom group, and Rivers and Rights conducted field research and held meetings with academics and residents in the Kok, Sai, Ruak, and Mekong river basins across multiple communities in Chiang Mai and Chiang Rai provinces. UN Working Group on Business and Human Rights representatives and Office of the UN High Commissioner for Human Rights (OHCHR) officials observed the field work.
At Mae Sai district, Thongkham Inprom, chairman of the Mae Sai irrigation canal water users group, reported that Mae Sai is a critical agricultural area with over 60,000 rai of farmland supporting 47 villages across four subdistricts. The Mae Sai and Ruak rivers are used directly for irrigation and as raw water sources for drinking water systems. Heavy metal contamination exceeding safety standards has been detected 18 times. "Although current rice yields test within acceptable limits, farmers worry about long-term impacts—toxin accumulation in soil, groundwater, and the food chain," he stated, urging the government to provide clean groundwater with solar-powered pumping systems and transparent water quality disclosure.
Fishers from Sop Kok village in Chiang Saen reported severe economic impacts from Mekong contamination, with fish prices dropping by half as consumers avoid Mekong fish. They also noted that upstream Chinese dams cause unnatural water level fluctuations, compounded by toxic sludge from mining in neighboring countries. Residents called for urgent government support for standard water filtration systems in their community, which relies directly on Mekong water.
The team toured the Mekong along the Thai-Lao border from Chiang Khong to the Ing River mouth. Village headman Manop Munnirat of Pak Ing Tai reported dramatic changes: fish species have dwindled from hundreds to dozens, and fishing boats decreased from hundreds to just ten. Residents now must seek work elsewhere.
