Heavy Metal Concentrations in Surface Water of the Lower Mekong River Basin (Vietnam)

Purpose: The research is carried out to determine the concentration of heavy metals in surface water of the downstream Mekong River. Methods: The sampling method follows the Vietnamese national standard (TCVN 6663-6:2018, ISO 5667-6:2014). The heavy metal indicators analyzed using an atomic absorption spectroscopy machine. The lowest detection level of the measurement method is approximately 0.2µg (on average for all indicators measured). Results and discussion: Among the 5 parameters studied in December 2023, the average concentration has not exceeded the national standards of Vietnam (the maximum allowable values for parameters affecting human health), but it is approaching the limit (especially Zn at 454.69 µg/l compared to 500 µg/l). At many locations, the levels of Zn and Cu have exceeded the standards (at Cửa Đại, Ba Lai, Cung Hầu). Compared to our research conducted in 2013, except for Cd, the average concentrations of all other parameters are increasing. Compared to the standards of some countries such as the United States, Canada, and Russia, the levels of heavy metals in the research area are high, especially Zn and Cu which are much higher. Implications of the research: The heavy metal concentration in the study area increases towards the sea, correlating with the pH index and river-sea mixing. Human activities contribute to heavy metal accumulation in the lower Mekong region's water. Management agencies must develop policies and measures to minimize NCDs' impact and ensure sustainable development. Originality/value: The research findings will guide rational production and daily activities in the Mekong Delta, a region severely impacted by climate change, to ensure sustainable development.