Citizen Science Maps Global Microplastic Hotspots—and the Plastics Behind Them

A University of Portsmouth analysis of 1,089 shoreline surveys from the Big Microplastic Survey (2018–2024) reveals stark regional differences in the types and concentrations of plastics contaminating coasts worldwide.

The study—spanning 39 countries and nearly 59,000 items—highlights how volunteer-collected data can expose patterns traditional campaigns might miss, informing policy and cleanup priorities as negotiations continue on a UN treaty to end plastic pollution.

phys.org

• Massive global dataset — Researchers synthesized 1,089 citizen-led coastal surveys across 39 countries, cataloging ~59,000 plastic pieces to map pollution patterns.
• Nurdles dominate — Pre-production pellets (“nurdles”) were the most common plastic type; the Netherlands reported the highest counts, 14× the next worst-affected nation after a container-loss incident.
• Bio-bead clusters — Microbeads used in wastewater treatment were heavily concentrated in the Netherlands and Honduras; the UK ranked third by average counts per sample.
• Secondary fragments vary by region — Weathered fragments from larger items were especially common in Kenya and Honduras, indicating strong local inputs and breakdown dynamics.
• EPS hotspots — Expanded polystyrene (foam) pollution peaked in Thailand, Indonesia, and Portugal, pointing to packaging and fisheries sources.
• Color signature — White plastics predominated globally, followed by clear/opaque, blue, and green—useful forensic clues for source attribution.
• Citizen science at scale — Over 1,000 registrations from 66 countries show broad interest; the UK, US, and Australia contributed the most volunteers and surveys.
• Engagement challenge — Fewer than 20% of registrants submitted data, underscoring the need for sustained coordination, feedback, and support.
• NGOs as force multipliers — Non-governmental organizations were often the most effective local drivers, delivering the bulk of high-quality submissions in their regions.
• Policy relevance — Blending citizen science with conventional monitoring can fill data gaps, track microplastic spread, and guide action under the forthcoming UN plastics treaty—while building community ownership of solutions.