CHIANG RAI – Local groups and scholars are urging Thailand’s next government, regardless of who leads, to stop importing minerals from Myanmar’s Shan State. They also want action to close upstream mines along the Kok River and Sai River to fix heavy metal contamination that has forced residents to look for other sources of water.
Since 2021, Thailand has brought in nine types of minerals from Shan State, Myanmar, mostly through the Mae Sai border crossing. The value is high, with lead ore making up a large share. In 2023, imports of lead totalled 21,660,820 kilograms.
In 2024, the number dropped to 11,214,240 kilograms, and from January to July 2025, another 7,039,610 kilograms came in. Over these years, the total has reached 21,943,605 kilograms.
Manganese imports are even higher. In 2021, Thailand imported 7,261,855 kilograms. This jumped to over 20 million kilograms in both 2022 and 2023, with 12,274,876 kilograms in 2024, making 75,209,761 kilograms in total. Copper, tin, and zinc ore have also been brought in, though on a smaller scale.
Dr. Suebsakul Kitchanugul, a lecturer at the School of Social Innovation, Mae Fah Luang University, and a member of the Kok River, Sai River, Ruak River, and Khong River Protection Network, commented on recent developments.
Mining Along the Kok River
He pointed out that heavy rainfall in August 2025 highlighted clear changes. When mining on new sites along the Kok river bank stopped due to a lack of roads and facilities, the water quality improved fast, with less contamination, especially arsenic. However, mining is still active along the Sai River, where infrastructure exists, so arsenic levels remain above safety limits throughout the length of the river.
Dr. Suebsakul is calling on the incoming government to treat this problem seriously. Past efforts have fallen short. The latest move came from a Thai-Myanmar meeting on 20 August, where they agreed to create a joint committee to test water quality. But there is no set date for the committee, so mining in Myanmar continues to affect Thai resources.
He wants the government to use trade measures and stop importing minerals from Shan State. If not, these problems will continue to harm Thailand’s water supply. Provincial waterworks used to rely on water from the Kok and Sai Rivers and the Mekong for tap water.
Now, due to the contamination, they need new sources. Officials have started to look at drawing raw water from the Khun River for use in Mae Sai’s border area, but this will require building a reservoir, which is expensive.
There is hope that the new government will act quickly through the Royal Irrigation Department to support the construction.
For Chiang Rai’s main city, the switch is from the Kok River to the Lao River. This move solves the contamination issue and does not need a reservoir like the Khun River option. Residents and experts want concrete action to protect public health and the environment.
Stopping imports and managing mining is a step they hope to see soon.
About the Kok River
The Kok River, also known as Mae Nam Kok, is a significant tributary of the Mekong River, flowing through northern Thailand’s Chiang Rai and Chiang Mai provinces, with its source in the Daen Lao Range in Myanmar’s Shan State.
Originating in Myanmar, the river flows eastward across the Myanmar-Thailand border at Tha Ton, Chiang Mai Province. It continues through Mae Ai District and most of Chiang Rai Province, passing Mueang Chiang Rai, Mae Chan, Wiang Chai, and Chiang Saen districts before joining the Mekong at Sop Kok, opposite the Lao border.
The river is wide, shallow, and slow-moving, with about 600 meters of small-scale whitewater between Tha Ton and Chiang Rai. The Kok River stretches approximately 177 miles (285 kilometres). Its main tributaries include the Fang River and the Lao River, the latter originating in the Phi Pan Nam Range.
Since early 2025, the Kok River has faced severe arsenic and heavy metal contamination, primarily from upstream gold and manganese mining in Myanmar’s Wa-controlled region. Water tests have shown arsenic levels exceeding Thailand’s safety standard of 0.01 mg/L, with readings as high as 0.034 mg/L at some points.
This has led to murky waters, health risks like rashes for locals and animals, and ecosystem damage, impacting fishing and tourism. Recent tests indicate a slight drop in arsenic levels, possibly due to the temporary closure of a mine following storms, but contamination remains a critical issue. The Mekong River Commission is facilitating joint monitoring between Thailand and Myanmar to address this transboundary pollution.
