Sources and pathways of marine litter

This background report, prepared by the Stockholm Environment Institute Tallinn Centre for the BLASTIC project, identifies and classifies the land-based sources and pathways of macroplastic marine litter (>25 mm) to assist municipalities in developing monitoring programmes and action plans, with a specific focus on the Baltic Sea region.

• Land-based activities are the primary contributors to marine litter globally and specifically in the Baltic Sea region, with estimates suggesting that up to 80% of all marine litter originates from land.
• In the Central Baltic Region, plastic items constitute 60% of marine litter, and more than half of those plastics are packaging waste.
• The report identifies three primary pathways through which litter is transported from land to the sea: human activity (direct dumping), wind, and water (which includes drains, rivers, runoff, stormwater, and sewerage).
• Sewerage systems are a critical pathway for urban marine litter, particularly through the discharge of untreated municipal sewage and sewer overflows during heavy rain events when treatment capacity is exceeded.
• The report proposes a classification of land-based sources relevant for municipal management, categorising them into: Recreation and tourism, General littering, Waste water collection and treatment systems, Municipal waste collection/treatment systems, Cleaning of public spaces, Industry and commercial sector, and Agriculture.
• Recreational and tourism activities are highlighted as one of the most significant land-based sources, often driven by inadequate infrastructure such as insufficient waste bins and low environmental awareness.

APA

Moora, H., & Piirsalu, E. (2016). Sources and pathways of marine litter. Stockholm Environment Institute. https://www.sei.org/wp-content/uploads/2017/12/blastic-backgroundreport-final.pdf

Chicago

Moora, Harri, and Evelin Piirsalu. Sources and pathways of marine litter. Stockholm Environment Institute, 2016. https://www.sei.org/wp-content/uploads/2017/12/blastic-backgroundreport-final.pdf.

Wikipedia

{{cite report |last1=Moora |first1=Harri |last2=Piirsalu |first2=Evelin |title=Sources and pathways of marine litter |publisher=Stockholm Environment Institute |date=2016 |url=https://www.sei.org/wp-content/uploads/2017/12/blastic-backgroundreport-final.pdf |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{moora2016sources, author = {Moora, Harri and Piirsalu, Evelin}, title = {{Sources and pathways of marine litter}}, institution = {Stockholm Environment Institute}, year = {2016}, url = {https://www.sei.org/wp-content/uploads/2017/12/blastic-backgroundreport-final.pdf}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }