The Mekong River Commission (MRC) Secretariat is warning about a “moderately serious” situation following the detection of heavy metal contamination in the Mekong River, believed to have originated from poorly regulated mining operations in a self-administered region of Myanmar.
In remarks on Thursday, the MRC said recent water quality assessments identified elevated levels of arsenic at multiple locations along the river.
The testing, which focused on the Kok River and parts of the Mekong, showed that arsenic concentrations at four out of five sampling sites exceeded the standard limit of 0.01 mg/L.
The assessments showed upstream sites at the upper Myanmar-Laos border as well as the downstream site at Luang Prabang, Laos had arsenic levels below the threshold.
However, higher levels of arsenic were detected in the section between a point slightly north of the Golden Triangle at the Myanmar-Laos border and Thailand’s Chiang Khong district at the Thailand-Laos border.
The MRC said no lead contamination was detected in the Mekong stretch within Laos. This suggests the contamination may stem from transboundary sources.
It also cited comparative data from the Thai Pollution Control Department (PCD) in May that showed arsenic levels at around 0.025 mg/L on average.
Based on these findings, the MRC has classified the situation as “moderately serious” under its Technical Guidelines for Water Quality Emergency Response and Management.
In response, the MRC Secretariat is arranging joint assessments to strengthen cross-border water quality monitoring. A key meeting and field visit is planned for July 21 in Chiang Rai.
The session aims to secure agreement among Laos, Myanmar and Thailand on a monitoring plan and to outline a long-term roadmap for regional cooperation.
This latest effort by the MRC comes in response to a growing transboundary water pollution crisis, largely attributed to substandard mining practices in Myanmar.
Heavy metals such as arsenic have been detected in the Kok and Sai rivers, which flow through northern Thailand before merging with the Mekong.
Meanwhile, the Thai PCD said it is monitoring the situation closely, noting that contamination levels typically worsen during the rainy season.
Officials have advised the public in affected areas to avoid using river water for household or agricultural purposes due to potential health risks.
In parallel, the government is also preparing to engage in direct negotiations with Myanmar in pursuit of a lasting resolution to the issue.
Authorities underscored the need to protect local communities that rely heavily on the region’s rivers.
This article first appeared in the Bangkok Post.
