Plastic pollution is a pervasive threat to California’s aquatic environments, with impacts spanning ecological health, human well-being, and the integrity of natural resources. From visible macroplastics (trash) littering shorelines, cities, and waterways to microscopic particles infiltrating water, sediment, and wildlife, plastics are now present in virtually all areas across California. The state of California has a longstanding history and commitment to environmental stewardship and policy innovation, including concerted efforts to manage and reduce plastic pollution. This report was commissioned by the California Ocean Protection Council (OPC) to articulate a statewide strategy and planning framework for a future statewide plastics monitoring program that will inform management actions to mitigate plastic pollution in state waters.

This report describes a Statewide Microplastics Monitoring Strategy (Section 2) and a Statewide Macroplastics Monitoring Strategy (Section 4). Strategies to address microplastics (plastics smaller than 5 mm) and macroplastics (trash composed of plastic, defined in water quality policies and regulations as larger than 5 mm in size) are separate due to different monitoring information needs, sampling methods, and groups engaged in monitoring. The Microplastics and Macroplastics Monitoring Strategies together make up the Statewide Plastics Monitoring Strategy. This Monitoring Strategy does not specify future program implementation by a specific agency, program, or regulatory means. It can be implemented in different ways to meet the needs of different entities and support discussions regarding state resources that may be needed to implement future monitoring program(s). It lays the foundation for a scientific, scalable, statewide program that can empower California to reduce plastic pollution through improved data and information, informed policies, and enhanced community engagement.