MRC Addresses Kok River Water Quality Concerns, Regional Meeting Set for Next Steps

Vientiane, Lao PDR, 3 July 2025 - The Mekong River Commission (MRC) Secretariat is working closely with national agencies from Lao PDR, Myanmar, and Thailand, to address concerns over water quality in the Kok River and parts of the Mekong River. A recent water quality assessment conducted by the Secretariat revealed that four out of five sampling sites had arsenic concentrations above the standard limit of 0.01 mg/L.

The upstream at Houa Khong and C1, as well as downstream at Luang Prabang, showed arsenic levels below the threshold. The contamination was detected from C2 to C5 in which imply that the contamination is likely entering the river between C1 and C5. Unlike earlier findings from Thailand's Kok River, no lead was detected in the Mekong River stretch within Lao PDR.

When compared with the May 2025 assessment by the Thailand's Pollution Control Department (PCD), arsenic levels in the Mekong remained consistent at around 0.025 mg/L. Arsenic was also detected along the Lao-Myanmar border, hinting at possible sources beyond national boundaries.

Based on these findings, the issue has been classified as a "moderately serious" situation under the MRC's Technical Guidelines for Water Quality Emergency Response and Management. As such, the MRC has notified the potentially affected countries.

To address the issue, the MRC Secretariat has facilitated a series of meetings and assessments to advance a proposal for joint water quality monitoring among the three countries. An upcoming meeting and field visit is scheduled on 21 July 2025 in Chiang Rai, Thailand. It aims to build consensus on the proposal and develop a road map for future collaboration, with the MRC Secretariat facilitating the exchange of ideas and technical inputs.

The MRC remains committed to supporting its Member Countries and Dialogue Partners in promoting data sharing, regional cooperation, and the joint management of transboundary water resources to ensure a healthier Mekong Basin.

About the Mekong River Commission

The MRC is an intergovernmental organization established in 1995 to boost regional dialogue and cooperation in the Lower Mekong River Basin. Based on the Mekong Agreement among Cambodia, Lao PDR, Thailand and Viet Nam, the MRC serves as both a regional platform for water diplomacy and a knowledge hub - to manage water resources and support sustainable development of the region.

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For more information, please contact:

Ms. MAO Chandaly Communications Officer for Press Mekong River Commission Secretariat Email: chandaly@mrcmekong.org