Vientiane, Lao PDR, 5 October 2026 – Following the latest monitoring results reported in June 2026, five additional rounds of water sampling were conducted on 3 July, 22 July, 7 August, 19 August, and 3 September 2026 at three monitoring sites in Luang Prabang and Bokeo provinces, Lao PDR. The monitoring covered Luang Prabang, Bokeo C2, and Houay Xay C5.

The results indicated that arsenic concentrations at all three monitored sites remained below the standard limit of 0.01 mg/L under the Technical Guidelines on the Implementation of the Procedures for Water Quality (TGWQ) for the Protection of Human Health and Aquatic Life. Across the five sampling rounds, 15 individual results were reported, with concentrations ranging from below 0.0009 mg/L to 0.0020 mg/L. The highest concentration, 0.0020 mg/L, was recorded at Houay Xay C5 on 3 July 2026 and remained well below the applicable standard limit. No result exceeded 0.01 mg/L during the five-round monitoring period. The latest sampling on 3 September 2026 recorded an arsenic concentration of 0.0010 mg/L in Luang Prabang, 0.0011 mg/L at Bokeo C2, and 0.0012 mg/L at Houay Xay C5.

The samples were analysed by the Biotechnology and Ecology Institute (BEI) of the Environmental Quality Analysis Centre in Lao PDR, using standard methods under its ISO/IEC 17025:2017-accredited quality management system. The results provide an updated technical snapshot of arsenic levels at the monitored locations during the sampling period and will contribute to continuing evidence-based assessment of Mekong water quality conditions. Monitoring results will be updated regularly as new data become available.

The MRC Secretariat will continue supporting cooperation among Member Countries on water quality monitoring, technical assessment and information sharing across the Lower Mekong Basin. Continued cooperation among Member Countries remains central to protecting the Mekong River and supporting shared, sustainable benefits across the basin.

 

About the Mekong River Commission

The MRC is an intergovernmental organisation 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: 
Chandaly Mao (Ms.)
Communications Officer for Press
Mekong River Commission Secretariat
Email: chandaly@mrcmekong.org