Lower Mekong River Basin: comprehensive monitoring of transboundary riverine plastic pollution

The Mekong River Basin is one of the largest and most biodiverse river basins in the world, spreading over more than 795,000 km2 and extending over 5,000 km through six different countries and providing a home to more than 70 million people alone in its lower reaches. In a recent study, the Mekong River was named as one of the 10 major contributors to marine plastic pollution.

In the Mekong River Commission (MRC)’s own assessment of the status and trends of plastic waste pollution, the amount of plastic waste produced by its Member Countries (MCs) were estimated to be about 0.3, 0.2, 3.5 and 3.3 million tons per year, respectively for Cambodia, Lao PDR, Thailand, and Viet Nam.

To address the growing concern on the potential effects of plastic debris pollution on freshwater fauna of the Mekong River, the MRC MCs have jointly developed a detailed methodology for a cost-effective and long-term monitoring of transboundary riverine plastic pollution. It aims at generating information and knowledge to support decision-making on the management of riverine plastic pollution in the Lower Mekong River Basin (LMB), including through the conduct of an in-depth analysis of existing methodologies to identify the most suitable one for the region. The chosen approach underwent extensive piloting
and consultation at both country and regional levels to ensure its adaptability to the unique situations of the Mekong River.

Following rigorous pilot processes and consultations, three protocols were established: Protocol for Riverine Macroplastic Monitoring, Protocol for Riverine Microplastic Monitoring, and Protocol for Microplastic in Fish Monitoring. This development process not only facilitated the adaptation of the methodology to the Mekong River’s context but also fostered ownership among MRC Member Countries, leading to its integration into the existing MRC routine Water Quality Monitoring Network (WQMN) for long-term implementation. Since finalization in 2022, the MRC is now providing support to the national line agencies of the LMB Countries in building their capacities for sustainablec implementation of the finalized protocols. The monitoring of riverine plastic will commence on a routine basis as part of the MRC WQMN and will contribute to the achievement of the MRC Basin Development Strategies for 2021 to 2030 and ultimately the objectives of the 1995 Mekong Agreement.