Water Quality Degradation in the Lower Mekong Basin

Based on biological and physical-chemical data collected over the last two decades, the authors evaluated spatial-temporal water quality of the Lower Mekong Basin (LMB) using biotic and abiotic assessment metrics. They found that during the 2000s, water quality in the LMB was unpolluted, with “very good” metrics for tributary rivers and “good” status for mainstem rivers. However, during the last decade, water quality has been degraded in the LMB, particularly near Vientiane City; the Sekong, Sesan, and Srepok (3S) Rivers; the Tonle Sap Lake system; and the Mekong Delta. Water quality degradation likely corresponds to flow alteration, erosion, sediment trapping, and point and non-point wastewater, which have occurred from rapid hydropower development, deforestation, intensive agriculture, plastic pollution, and urbanization.

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Sor, R., P.B. Ngor, S. Soum, S. Chandra, Z.S. Hogan, and S.E. Null

Publication Date

31 May 2021

Publication Name



water quality monitoring and assessment; macroinvertebrates; water quality index; BMWP score; Prati index; 3S Rivers; Tonle Sap Lake; water pollution