Myanmar Kachin heavy rare earth mining and Kok River arsenic
- Government and regulators Thailand's Pollution Control Department: Measured arsenic at 2.5 times the WHO limit at 4 of 5 sites; the source was identified as rare earth and gold mines in Shan State. Mongabay
- International bodies Mekong River Commission: Assessment found serious arsenic contamination in the Mekong and Kok rivers due mainly to mining operations (as headlined by BHRRC). Business & Human Rights Resource Centre
- Company or project Mine operators in Myanmar: No response is on record in the sources reviewed.
Thai and Mekong River Commission measurements in 2025 found arsenic at 2.5 times the World Health Organization limit at four of five sites on the Kok and Mekong rivers. Reports attributed it mainly to rare earth and gold mining in Myanmar's Shan State.
Measurements by Thailand's Pollution Control Department and the Mekong River Commission, June-July 2025.
Status As of July 2025: measurements found arsenic at 2.5 times the WHO limit at four of five sites on the Kok and Mekong rivers.
- Farmers in Thailand — Arsenic risk to rice irrigated with Kok River water.
What happened
In June and July 2025, Thailand's Pollution Control Department and the Mekong River Commission measured arsenic in the Kok and Mekong rivers. At four of five sites the level was 2.5 times the World Health Organization limit. The reports linked the contamination to rare earth and gold mines in Myanmar's Shan State.
Mongabay reported that rare earth mining in Myanmar was blamed for toxic river spillover into Thailand. The Business and Human Rights Resource Centre headlined the Mekong River Commission's assessment as showing serious arsenic contamination in the Mekong and Kok rivers due mainly to mining operations.
Arsenic risk to rice irrigated with Kok River water in Thailand was also noted.
- 2024Global Witness publishes an investigation into heavy rare earth mining in Myanmar (claims unverified, see unknown)
- 2025Thai and Mekong River Commission measurements find arsenic at 2.5 times the WHO limit at four of five sites on the Kok and Mekong
What was said
Where accounts differ
Each party's account, side by side, with its source. The record does not settle these points; it shows them.
Measured arsenic at 2.5 times the WHO limit at 4 of 5 sites; the source was identified as rare earth and gold mines in Shan State.
MongabayAssessment found serious arsenic contamination in the Mekong and Kok rivers due mainly to mining operations (as headlined by BHRRC).
Business & Human Rights Resource CentreNo response is on record in the sources reviewed.
How it looked
Shown
Recorded
- Thailand's Pollution Control Department and the Mekong River Commission measured arsenic at 2.5 times the WHO limit at 4 of 5 sites on the Kok and Mekong rivers; the source was identified as rare earth and gold mines in Shan State.
- The Mekong River Commission's assessment found the contamination due mainly to mining operations (as headlined by the Business and Human Rights Resource Centre).
In court and with insurers
Lawsuits and rulings
Insurers
What nature saw
Nature's report opens this page. Below: further outcomes measured on the ground.
What we don't know
Nature
- Not measured Harm to nature: No independent ecological evaluation is on record.
- Disputed Where does the arsenic in the Kok and Mekong rivers come from?
Accounts
- None on record Mine operators in Myanmar: No response is on record in the sources reviewed.
Record
- Insufficient Reported but not independently verified: Global Witness (May 2024) reported that Myanmar had become the largest source of heavy rare earths for China, that China's imports from Myanmar rose from 19,500 tonnes in 2021 to 41,700 tonnes in 2023, more than twice its domestic production, and that about 300 sites in Kachin held more than 2,700 leach ponds in 2022.
- Insufficient Reported but not independently verified: that armed groups controlled mines in Kachin.
Did the harm stop?
The sources reviewed do not record any end to the arsenic contamination.
Who paid?
The sources reviewed record the contamination reaching rivers in Thailand, a country with no commercial link to the mines.
Sources
Press and investigations
Communities and civil society
- Southeast Asia: Mekong River Commission's assessment reveals serious arsenic contamination in the Mekong and Kok rivers due mainly to mining operationsBusiness & Human Rights Resource Centre · 2025-07
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