Thailand: The devastating impact of arsenic polluting northern rivers

The rivers in northern Thailand are heavily contaminated with arsenic from rare earth mines in Burma and gold mines in Laos.

See: China's rush for rare earths in Burma is poisoning Thailand

This is causing the collapse of tourism, distress for residents, and an unprecedented environmental crisis.

The water of death is driving tourists away

Apichit Panwichai, a resident of Chiang Rai province, shows a dead turtle on the banks of the Kok River.

The mountainous landscapes and fresh, clean air used to attract visitors to the village of Thaton, in Mae Ai District, Chiang Mai, especially during the high season starting from November.

Today, the village is like a ghost town.

The streets are empty, the restaurants are deserted, and only a few customers remain in the hotels by the river.

The Kok River, once one of the most well-known attractions in the province, is now at the center of what has been described as the largest transboundary pollution crisis in ASEAN.

Poorly regulated rare earth mining in Myanmar has caused toxic runoff, turning the river, which was the lifeblood of tourism, into what locals ominously call 'water of death'.

Saranya Sukcharaen, owner of the 22-room Saranya River House, said:

"More than half of the bookings were canceled after the Pollution Control Department (PCD) detected heavy metals, particularly arsenic, in the river at levels well above safety limits."

Since then, travel agencies have contacted her about the water quality.

Their foreign clients are concerned not only about the river but also about the tap water.

"Some have asked if it's safe enough to brush their teeth.

I explained to them that our water source is underground and doesn't come from the river.

I even took samples and sent them to a lab for analysis," she said.

"I showed them the safety certificate.

It cost me extra, but I have to help myself if I want to survive."

Tourism at a standstill and local economy in free fall

The Kok River in Chiang Mai's Mae Ai district. Photo: Thai PBS World

Born and raised in Thaton, Mrs. Saranya has worked in tourism for decades.

She believes the crisis is almost impossible to resolve because its root cause lies outside Thai borders.

She sees little hope for the river's restoration, noting that heavy metals flow downstream, settle, and accumulate in sediments, unlike seasonal air pollution, which eventually dissipates.

She explains that bamboo rafting, once the community's main tourist activity, has virtually disappeared because tourists no longer want to risk contact with contaminated water.

Tourists used to book three-day, two-night packages that brought in around 20 million baht per year for the village.

These trips typically included an upstream rafting trip to visit hill tribes, who relied on tourism for their income.

Those days are gone, she says, as travel agencies turn to other destinations.

See also: Arsenic pollution in Thailand: tourists flee Chiang Rai beach

Abandoned residents face contamination

Employees from the pollution control department are collecting water from a river in Thailand. Photo: Thai PBS World

Kanchana Kaewprapaenee, another operator, shares this pain.

She runs a food stall and was hoping to earn around 400,000 baht (10,786 euros) during the Songkran

These hopes were shattered after the PCD reported excessive arsenic levels in March 2025, following a local complaint about abnormally dark brown water.

“There has been no real help from the government,” she said.

“Our request for health check-ups was ignored, even though we are the victims.

We are desperate, and I may have to wait until the day I find out that my body contains dangerous levels of toxins.”

See also: Northern Thailand: Children poisoned by arsenic from Burmese mines

A river crisis with regional ramifications

Blistered fish caught in the Mekong River. Photo: Thai PBS World

The PCD is now monitoring arsenic and other heavy metals in the Kok, Sai, and Ruak rivers, as well as the Mekong, all affected by upstream mining in neighboring countries.

Heavy metals continue to be detected, although levels fluctuate.

See: Thailand: Mutant fish discovered in the Mekong, arsenic alert

Uncertain and disputed technical solutions

Fisherman in a river in northern Thailand. Photo: The Nation Thailand

The Ministry of Natural Resources and Environment has proposed building a dam to retain sediments, but residents fear it will hinder river transport.

A smaller check dam has also been suggested for the highland forests to intercept toxic sediments before they reach the river, but concerns remain about its high cost and limited impact.

Suebsakun Kidnukorn, a professor at Mae Fah Luang University's Faculty of Innovation, said rehabilitation can only begin once the source of pollution, namely unregulated mines in Burma, has stopped.

Thaton is the first point where the Kok River enters Thailand, and agricultural land has also suffered.

Some companies have refused to provide seeds under contract farming programs for fear of arsenic contamination.

The region is a major production center for miniature corn and roselle for the Japanese market.

“The situation will worsen over the next three years if these mines are not urgently closed,” he warned.

“The impact on vulnerable groups, especially pregnant women, will be immense.”

Uncontrolled mines at Thailand's doorstep

Rare earth mining in the Kachin region of Myanmar

Brian Eyler, director of the Energy, Water and Sustainability program at the Stimson Center, has expressed concern about the rapid expansion of mining in mainland Southeast Asia (2,419 sites to date).

Notably, the exploitation of rare earths in Burma and gold mining in Laos.

Many of these sites are located near the Thai border and the Mekong.

The PCD has also recently detected high levels of arsenic in Loei and Nakhon Phanom provinces.

Mekong tributaries are likely to be the main vectors for transporting toxins into the river network.

However, these tributaries are not under the jurisdiction of the Mekong Commission, which only oversees the main course of the river.

ASEAN overwhelmed, China as a potential arbiter?

Soldiers from the United Wa State Army (UWSA) at a tin ore processing plant in Man Maw, a Wa ethnic territory in northeastern Burma, in October 2016. Photo: Reuters

The existing ASEAN frameworks for transboundary pollution are unlikely to solve the problem, said Mr. Eyler.

In contrast, cooperation with China could be considered, as it plays a central role in regional mining, both as a major investor and main buyer.

See: Red Wa poisons Thailand: drugs and arsenic pollution

See also:

Thailand: High levels of arsenic detected in the Mekong and its tributaries

Arsenic poisoning in rivers: Thailand relies on filter nets

Thailand: Dangerous arsenic levels confirmed in northern rivers

Thailand: Arsenic-poisoned rivers threaten thousands of lives

Source: Bangkok Post