Addressing microplastics in drinking water in the global plastics treaty – Gaps, challenges and opportunities

Abstract The escalating presence of microplastics (<5 mm) in drinking water presents urgent environmental and health challenges, yet the United Nations Environment Programme’s (UNEP) Global Plastics Treaty draft texts, including UNEP/PP/INC.5/4 and the Chair’s Text, lack robust provisions to address this issue. This Letter to the Editor analyzes deficiencies in the treaty’s approach, identifying critical gaps in standardized terminology, globally consistent monitoring methodologies, comprehensive source control and enforceable international regulations. Leveraging insights from California’s innovative microplastics monitoring framework, which employs spectroscopy-based detection and provisional health thresholds, we highlight scalable solutions for global policy. Key obstacles include technological disparities, economic reliance on plastic production, limited toxicological data and geopolitical barriers to unified action. We propose targeted strategies for the Intergovernmental Negotiating Committee (INC-5.2), including adopting precise microplastics definitions, establishing universal detection protocols, regulating both primary and secondary microplastic sources and supporting research and capacity-building in low-resource regions. These measures aim to enhance the treaty’s ability to mitigate microplastic pollution in drinking water, fostering science-driven global cooperation to protect ecosystems and public health.