Systematic-based approach to marine litter prevention in coastal environment: lessons and successes from the PROMAR project implementation in Guyana

Marine litter remains a persistent environmental challenge in Caribbean coastal environments, where land-based plastic waste constitutes the dominant source of debris entering marine systems. This study evaluates the implementation of the Prevention of Marine Litter in the Caribbean Sea (PROMAR) project along the Guyana coast, applying a systematic, prevention-oriented framework grounded in circular economy principles. A mixed-methods approach was adopted across four flood-prone coastal communities, integrating household material flow analysis, knowledge-attitudes-practices surveys, drainage-level waste interception, beach litter assessments, and participatory stakeholder engagement. Results indicate that packaging plastics, particularly polyethylene terephthalate and high-density polyethylene, dominate intercepted and shoreline waste, confirming strong linkages between household disposal practices, drainage networks, and marine pollution pathways. Community waste-to-value hubs, incentive-based recovery schemes, and source-proximal interception measures collectively contributed to observable reductions in plastic leakage while improving awareness, participation, and local ownership of waste management practices. The findings demonstrate that technical interventions are most effective when reinforced by education, behavioral incentives, and multi-actor governance arrangements. Policy-relevant insights highlight the importance of Extended Producer Responsibility and decentralized recovery systems for sustaining and scaling marine litter prevention. The study provides transferable evidence that systematically designed, community-anchored circular interventions can deliver socially inclusive and environmentally effective solutions in vulnerable coastal settings.