The Kok River originates in Myanmar’s Shan State before flowing through Chiang Rai and Chiang Mai provinces and eventually joining the Mekong River. For communities living along its banks, the river provides drinking water, irrigation, fisheries, transportation, and cultural identity. Today, however, many residents fear that these lifelines are under threat from heavy metal contamination linked to mining operations upstream in Myanmar.

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Concerns over the Kok River have intensified following reports of elevated concentrations of heavy metals, including arsenic, in rivers flowing from Myanmar into northern Thailand. Environmental groups and local communities have linked the contamination to expanding rare earth and mineral mining operations in Myanmar that are reportedly financed by Chinese investors.

... rare earth and gold mines along the Kok River in Mong Yawn ... are operated by China Investment Mining Company, backed by the Chinese government ...

Thai authorities have been testing the water of the Kok River every two weeks since April 2025, and found levels of arsenic and lead above safety standards ...

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For Indigenous communities in northern Thailand, protecting the Kok River is inseparable from protecting their lands, livelihoods, and cultural heritage.

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Participants in the Kok River Peace Walk emphasized that communities who have lived alongside these rivers for generations possess valuable ecological knowledge that should guide conservation efforts. They called for stronger recognition of Indigenous land rights, meaningful community participation in environmental decision-making, transparent environmental monitoring, and greater protection for environmental defenders.

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