KPL
Arsenic levels recorded in the Mekong River at monitoring sites in Bokeo and Luang Prabang provinces remained below the applicable safety standard during five rounds of sampling conducted between July and September 2026.
The latest monitoring covered three sites—Luang Prabang, Bokeo C2 and Houay Xay C5—with samples collected on July 3, July 22, August 7, August 19 and September 3.
All 15 test results were below the standard limit of 0.01 milligrams per litre (mg/L) set under the Technical Guidelines on the Implementation of the Procedures for Water Quality for the Protection of Human Health and Aquatic Life.
Arsenic concentrations ranged from below 0.0009 mg/L to 0.0020 mg/L. The highest reading, 0.0020 mg/L, was recorded at Houay Xay C5 on July 3 and remained well below the standard.
The latest sampling on September 3 recorded 0.0010 mg/L at Luang Prabang, 0.0011 mg/L at Bokeo C2 and 0.0012 mg/L at Houay Xay C5.
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The samples were analysed by the Biotechnology and Ecology Institute of the Environmental Quality Analysis Centre in Laos using standard methods under its ISO/IEC 17025:2017-accredited quality management system.
The monitoring provides an updated assessment of arsenic levels at the three sites during the sampling period. The Mekong River Commission Secretariat will continue supporting water-quality monitoring, technical assessment and information sharing among member countries across the Lower Mekong Basin.
KPL
