Ocean Plastic Evidence Library — Sourced Entries for a Nonprofit "Evidence" Page

Summary

Answer first: The authoritative literature supports a library of 80 entries (Sections 1–7 below), each with exact title, publisher/journal, year, a URL actually found in a source on 2026-10-28, and a one-line plain-language finding. Confidence: high for the core peer-reviewed and UN/OECD/WHO/NOAA entries (4 sources verified live on 2026-10-28 — WHO drinking-water report, UNEP From Pollution to Solution press release, NOAA Economic Loss page, Kikaki et al. 2020 — the rest are web-index sources, flagged per entry in Sources). The library's framing arc is supported, with honest limits:

Flagged throughout: "more plastic than fish by 2050" (unproven scenario), "a credit card of plastic a week" (refuted), Motagua "2% of global / world's most polluting river" (operator claim, conflicting tonnages), ghost gear "640,000 t/yr" (legacy estimate its own source disowns), "90% of seabirds" (model estimate, often misworded), and all trillion-dollar cost figures (modelled externalities, not measured spending).

Findings

1. THE SCALE OF THE PROBLEM (12 entries)

1. "Plastic waste inputs from land into the ocean" — Jambeck et al., Science, 2015. https://pubmed.ncbi.nlm.nih.gov:443/25678662/ — Of 275 Mt of plastic waste generated in 192 coastal countries in 2010, an estimated 4.8–12.7 Mt entered the ocean.
2. "Production, use, and fate of all plastics ever made" — Geyer, Jambeck & Law, Science Advances, 2017. https://pubmed.ncbi.nlm.nih.gov/28776036/ — Humanity had made 8,300 Mt of virgin plastic by 2015; of ~6,300 Mt of waste, only 9% was recycled and 79% sits in landfills or the environment.
3. "Plastic Pollution in the World's Oceans: More than 5 Trillion Plastic Pieces Weighing over 250,000 Tons Afloat at Sea" — Eriksen et al., PLOS ONE, 2014. http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0111913 — At minimum 5.25 trillion plastic particles weighing 268,940 tons were afloat, counted across 24 expeditions (2007–2013).
4. "River plastic emissions to the world's oceans" — Lebreton et al., Nature Communications, 2017. https://ideas.repec.Org/a/nat/natcom/v8y2017i1d10.1038_ncomms15611.html — Rivers deliver an estimated 1.15–2.41 Mt of plastic to the oceans each year, with the top 20 rivers (mostly in Asia) contributing 67%.
5. "Export of plastic debris by rivers into the sea" — Schmidt, Krauth & Wagner, Environmental Science & Technology, 2017. https://www.ufz.de/index.php?en=20939&pub_id=19342 — An earlier model put river exports at 0.41–4 Mt/yr with the top 10 rivers contributing 88–95% — far more concentrated than later work (see entry 6); cite to show model uncertainty, not as current best estimate.
6. "More than 1000 rivers account for 80% of global riverine plastic emissions into the ocean" — Meijer et al., Science Advances, 2021. https://www.ufz.de/index.php?en=20939&pub_id=24659 — More than 1,000 rivers — many of them small urban rivers — account for 80% of riverine emissions of 0.8–2.7 Mt/yr, so interception must be widespread, not just on a few mega-rivers.
7. "Evidence that the Great Pacific Garbage Patch is rapidly accumulating plastic" — Lebreton et al., Scientific Reports, 2018. https://docs.rwu.edu/fcas_fp/462/ — The patch held at least 79 thousand tonnes of plastic across 1.6 million km² and 1.8 trillion pieces, with fishing nets making up at least 46% of the mass.
8. "Predicted growth in plastic waste exceeds efforts to mitigate plastic pollution" — Borrelle et al., Science, 2020. https://pubmed.ncbi.nlm.nih.gov:443/32943526/ — 19–23 Mt of plastic waste entered aquatic ecosystems in 2016, and even with current government commitments up to 53 Mt/yr could enter by 2030.
9. "A local-to-global emissions inventory of macroplastic pollution" — Cottom, Cook & Velis, Nature, 2024. https://www.researchbunny.com/papers/a-local-to-global-emissions-inventory-of-macroplastic-pollution-m9c0 — Across 50,702 municipalities, 52.1 Mt of macroplastic is emitted to the environment each year; littering is the largest source in rich countries, uncollected waste in poorer ones.
10. Global Plastics Outlook: Economic Drivers, Environmental Impacts and Policy Options — OECD, 2022. https://www.oecd.org/en/publications/2022/06/global-plastics-outlook_f065ef59/full-report/component-11.html?utm_source=chatgpt.com — Global plastics use reached 460 Mt in 2019 with only 9% of waste recycled; 22 Mt leaked to the environment, and 109 Mt had accumulated in rivers alone.
11. From Pollution to Solution: A Global Assessment of Marine Litter and Plastic Pollution — UNEP, 2021. https://www.grida.no/publications/747 — Plastics are the largest, most harmful and most persistent part of marine litter, at least 85% of it, with an estimated 75–199 Mt already in the oceans.
12. The New Plastics Economy: Rethinking the future of plastics — Ellen MacArthur Foundation / World Economic Forum, 2016. https://www.weforum.org/stories/nature-and-biodiversity/more-plastic-in-sea-than-fish-3-strategies — Source of the "more plastic than fish by 2050" line — flagged: a business-as-usual scenario, rated "Unproven" by AAP FactCheck (see Flagged Claims). https://aap.com.au/factcheck/fishy-figures-underpin-ministers-ocean-plastic-warning/

2. RIVERS AND CENTRAL AMERICA (9 entries)

13. "Remotely Sensing the Source and Transport of Marine Plastic Debris in Bay Islands of Honduras (Caribbean Sea)" — Kikaki et al., Remote Sensing, 2020. [verified live] https://www.mdpi.com/2072-4292/12/11/1727 — Satellite and field data (2014–2019) show plastic from Guatemala's and Honduras' rivers — Motagua, Ulúa, Cangrejal, Tinto, Aguán — reaching the Caribbean mainly in the August–March rainy season, drifting ~6 km/day.
14. Riverine plastic pollution (technical highlight) — UNEP interactive, n.d. (accessed 2026). https://www.unep.org/interactives/wwqa/technical-highlights/riverine-plastic-pollution — UNEP's explainer of the river science: small urban coastal rivers rank among the most polluting, and plastic retained in rivers is plastic kept out of the sea.
15. "How a Guatemalan river clean-up could help save the oceans" — International Collective in Support of Fishworkers (ICSF) news, n.d. https://icsf.net/newss/how-a-guatemalan-river-clean-up-could-help-save-the-oceans/ — The Motagua basin covers ~17,000 km² and 96 municipalities and is cited as carrying at least 8,500 tonnes of waste a year to the Caribbean, threatening the Mesoamerican Reef.
16. "Motagua: A river that rises in Guatemala and is threatened in Honduras" — El Universal interactive, 2022. https://interactivos.eluniversal.com.mx/2022/rio-motagua/index-eng.html — In the Honduran part of the basin only 5 of 24 municipalities have sanitary landfills while 19 rely on open dumps (per Honduras' environment ministry, MiAmbiente), so waste washes downstream and crusts beaches such as Omoa.
17. "Tons of waste removed from the beach 'La Travesia' in Honduras" — European External Action Service (EEAS), n.d. https://www.eeas.europa.eu/delegations/honduras/tons-waste-removed-beach-%E2%80%9Cla-travesia%E2%80%9D-honduras_en — An EU-supported Garífuna community cleanup removed over 15 tons of waste washed down by the Motagua (Guatemala) and Ulúa (Honduras) rivers onto one Honduran beach.
18. The Ocean Cleanup / Kia Guatemala initiative (press release reprint) — Classic Kia (dealer site reprinting the announcement), 2025. https://www.classickiaonline.com/blog/the-ocean-cleanup-and-kia-support-guatemala-with-initiative-to-stop-plastic-pollution-from-reaching-the-worlds-oceans — Operator source: The Ocean Cleanup, working with Guatemala's environment ministry (MARN), deployed Interceptor 006 in the Las Vacas River and Interceptor 021 in the lower Motagua basin; its ~20,000 tonnes/yr flow figure is an operator estimate (see Flagged Claims).
19. The problem of plastic pollution in the Río Motagua, Guatemala — EcoHubMap hotspot page, n.d. https://www.ecohubmap.com/hot-spot/the-problem-of-plastic-pollution-in-the-rio-motagua-guatemala/c096ebmldrtqpq3 — Maps the Motagua problem and the Interceptor Trashfence/006 installation on the Río Las Vacas tributary, repeating the "up to 20,000 tonnes/yr" operator figure.
20. 2024 Mesoamerican Reef Report Card — Healthy Reefs Initiative, 2024 (via International Coral Reef Initiative). https://icriforum.org/mesoamerican-report-card-2024/ — Across 286 monitored sites in Mexico, Belize, Guatemala and Honduras the reef's overall grade is still "poor" (39% of sites poor, 23% critical), though 2024 brought the first improvement in five years.
21. "Oceans Without Borders: Honduras and Guatemala Unite for Motagua" — 4ocean (commercial cleanup operator blog), n.d. https://www.4ocean.com/blogs/impact/oceans-without-borders — Operator source: cites Guatemala's environment ministry estimating over 8,000 tons of waste a year via the Motagua, with the Honduran town of Omoa repeatedly inundated by wash-ups.

3. EFFECTS ON MARINE LIFE (11 entries)

22. "The impact of debris on marine life" — Gall & Thompson, Marine Pollution Bulletin, 2015 (via University of Plymouth). https://www.plymouth.ac.uk/news/new-study-reveals-the-global-impact-of-debris-on-marine-life — Reviewing 340 publications: 693 species had encountered debris, ~44,000 individual animals were recorded entangled or ingesting it, plastic was ~92% of encounters, and 17% of affected species are threatened or near-threatened.
23. "Threat of plastic pollution to seabirds is global, pervasive, and increasing" — Wilcox, Van Sebille & Hardesty, PNAS, 2015 (via ScienceDaily). http://www.sciencedaily.com/releases/2015/08/150831163739.htm — 59% of seabird species studied had ingested plastic, the authors' model estimated 90% of individual seabirds alive had eaten plastic, and ingestion was predicted in 99% of species by 2050 — model estimate; see entry 24 for the wording caution.
24. "Quantitative overview of marine debris ingested by marine megafauna" — Kühn & van Franeker, Marine Pollution Bulletin, 2020. https://www.wur.nl/upload_mm/f/7/5/7b6018e7-c916-4299-bbb3-fc6527ad874e_Kuhn_2020_Plastic-review+OS.PDF — Across 747 studies, 914 species are affected by ingestion and/or entanglement; tubenosed seabirds show the highest individual rate (41%, averaging 9.9 particles per bird) — and the authors warn that "share of species with a record" is often wrongly reported as "share of individuals".
25. "A quantitative analysis linking sea turtle mortality and plastic debris ingestion" — Wilcox et al., Scientific Reports, 2018. https://www.researchgate.net/publication/327631951_A_quantitative_analysis_linking_sea_turtle_mortality_and_plastic_debris_ingestion — From 246 necropsies and 706 stranding records, a turtle's probability of death reached 50% at 14 pieces of plastic in its gut.
26. "Microplastic ingestion ubiquitous in marine turtles" — Duncan et al., Global Change Biology, 2019. https://pubmed.ncbi.nlm.nih.gov/30513551/ — Synthetic particles were found in every one of 102 marine turtles examined, spanning all 7 species and 3 ocean basins, mostly fibres.
27. "Understanding individual and population-level effects of plastic pollution on marine megafauna" — Senko et al., Endangered Species Research, 2020 (via ACAP news summary). https://acap.aq/latest-news/evidence-for-population-effects-from-plastic-pollution-remains-missing-for-seabirds — Individual harm (drowning, starvation, gut damage) is well documented, but no study in 50 years has shown direct evidence of population-level effects — do not claim proven population declines from plastic alone.
28. "Plastic waste associated with disease on coral reefs" — Lamb et al., Science, 2018 (via Cornell CALS). https://cals.cornell.edu/news/2018/01/oceanic-plastic-puts-coral-reefs-peril — Surveying 159 reefs and 124,000 corals in the Asia-Pacific, the likelihood of coral disease rose from 4% to 89% when coral was in contact with plastic, with ~11.1 billion plastic items estimated on the region's reefs.
29. Abandoned, lost or otherwise discarded fishing gear — Macfadyen, Huntington & Cappell, FAO Fisheries & Aquaculture Technical Paper No. 523 / UNEP Regional Seas Reports No. 185, 2009. https://www.fao.org/4/i0620e/i0620e00.htm — The foundational ghost-gear assessment: gillnets and traps/pots are likely the most common lost gear — and the report itself says the data do not allow a global estimate of how much is lost.
30. "Our oceans are haunted" (ghost fishing feature) — FAO Newsroom, 2021. http://www.fao.org/newsroom/story/Our-oceans-are-haunted/en — FAO's explainer repeats the widely quoted estimate of 640,000 tonnes of gear lost per year and ghost gear as one-tenth of ocean waste — flagged: legacy figures that entry 29's underlying report does not support as measured totals.
31. "Building evidence around ghost gear: Global trends and analysis for sustainable solutions at scale" — Richardson et al., Marine Pollution Bulletin, 2019 (NOAA repository). https://repository.library.noaa.gov/view/noaa/21803/noaa_21803_DS1.pdf — The Global Ghost Gear Initiative's evidence base on how lost gear harms wildlife and habitats and where solutions can scale.
32. "Estimates of fishing gear loss rates at a global scale: A literature review and meta-analysis" — Richardson et al., Fish and Fisheries, 2019 (via Phys.org/CSIRO). https://phys.org/news/2019-09-first-ever-commercial-fishing-gear-lost.amp — Meta-analysis of 68 studies: about 6% of nets, 9% of traps and 29% of lines are lost or discarded each year — a better-defined metric than the 640,000-tonne figure.

4. HUMAN HEALTH AND MICROPLASTICS (8 entries) — established vs uncertain stated in each line

33. Microplastics in drinking-water — World Health Organization, 2019. [verified live] https://www.who.int/publications-detail-redirect/9789241516198 — Established: microplastics occur in drinking-water. WHO's careful conclusion: on the limited evidence available they do not appear to pose a health risk at current levels, particles over 150 µm are unlikely to be absorbed, and far more research is urgently needed — this is "no demonstrated risk on thin data", not "proven safe".
34. "Microplastics in freshwaters and drinking water: Critical review and assessment of data quality" — Koelmans et al., Water Research, 2019. https://pubmed.ncbi.nlm.nih.gov/30861380/ — Much of the occurrence data behind public claims fails basic quality criteria, which is why exposure numbers vary so widely between studies.
35. "Microplastics in Seafood and the Implications for Human Health" — Smith, Love, Rochman & Neff, Current Environmental Health Reports, 2018. http://pubmed.ncbi.nlm.nih.gov/30116998/?dopt=Abstract — Established: people are exposed via seafood, especially shellfish eaten whole. Uncertain: whether that exposure harms health — any toxicity would depend on dose, polymer, size and surface chemistry, and the evidence was still emerging.
36. "Human Consumption of Microplastics" — Cox et al., Environmental Science & Technology, 2019. https://pubs.acs.org/action/downloadCitation?doi=10.1021%2Facs.est.9b01517&include=abs&format=ris&direct=true&downloadFileName=acs.est.9b01517 — Estimated intake of 39,000–52,000 particles a year from food (covering only ~15% of the diet), rising to 74,000–121,000 including inhalation — a count of particles, not a mass, and likely an underestimate by count.
37. "Microplastics and human health" — Vethaak & Legler, Science (Perspective), 2021. https://pubmed.ncbi.nlm.nih.gov/33574197/ — Effects on human health are unknown; laboratory and cell studies at high doses show oxidative stress and inflammation, and lung injury is documented only in workers exposed to high levels of plastic/textile fibre dust.
38. "Plasticenta: First evidence of microplastics in human placenta" — Ragusa et al., Environment International, 2021. https://iris.univpm.it/handle/11566/286406 — In a pilot of 6 placentas, 12 plastic fragments (5–10 µm) were found in 4 — detection in tissue, not demonstrated harm.
39. "Discovery and quantification of plastic particle pollution in human blood" — Leslie et al., Environment International, 2022 (via VU Amsterdam report). https://vakbladvoedingsindustrie.nl/en/article/microplastics-found-in-human-bloodstream — Plastic particles were measured in 17 of 22 blood donors (mean 1.6 µg/ml) — again detection, not evidence of disease causation.
40. Fact-check: the "credit card of plastic a week" claim — FirstCheck fact-check, n.d. (covering the 2019 WWF-commissioned University of Newcastle analysis, Pletz 2022 in Journal of Hazardous Materials Letters, and Mohamed Nor et al. 2021). https://firstcheck.in/fact-check-would-drinking-from-plastic-bottles-make-you-consume-a-credit-cards-worth-of-plastic-a-week/ — Do not use the 5 g/week figure: re-analysis found "severe errors" in the original calculation (Pletz estimates nearer one credit card per ~23,000 years) and modelling puts median intake in micrograms per week, over 1,000× lower.

5. THE COST OF INACTION AND THE CASE FOR SOURCE INTERCEPTION (10 entries)

41. Valuing Plastic / UNEP Year Book announcement: "Plastic waste causes financial damage of US$13 billion to marine ecosystems each year" — UNEP press release, 2014. http://www.unep.org/en/news-and-stories/press-release/plastic-waste-causes-financial-damage-us13-billion-marine-ecosystems — A conservative estimate of US$13 billion a year in financial damage to marine ecosystems, described by its authors as likely a significant underestimate; the wider natural-capital cost of plastic in consumer goods was put at US$75 billion a year.
42. "Global ecological, social and economic impacts of marine plastic" — Beaumont et al., Marine Pollution Bulletin, 2019. https://pubmed.ncbi.nlm.nih.gov/31232294/ — Nearly every marine ecosystem service is reduced by plastic; the authors conjecture a cost of $3,300–$33,000 per tonne of marine plastic per year — an explicitly first, modelled estimate, not a measured price.
43. "Economic Loss" (marine debris impacts) — NOAA Marine Debris Program, n.d. [verified live] https://marinedebris.noaa.gov/why-marine-debris-problem/economic-loss — Local, measured-scale evidence: doubling debris on coastal Alabama beaches was linked to 1 million fewer visitor days, $113 million less tourism spending and ~2,200 lost jobs, while removing derelict Chesapeake crab pots in high-density areas was linked to 38 million more pounds of blue crabs and $33.5 million in revenue (magnitude contested — see entry 78).
44. Plastics: The costs to society, the environment and the economy — WWF / Dalberg, 2021. https://wwf.panda.org/wwf_news/?3507866/These-costs-for-plastic-produced-in-2040-will-rise-to-US71-trillion-unless-urgent-action-is-taken — The lifetime societal cost of the plastic produced in 2019 alone is modelled at US$3.7 trillion (±$1 trillion), rising to US$7.1 trillion for 2040's production without action — modelled externalities, not money actually spent.
45. "Who pays for plastic pollution?" (lifetime cost inequity) — WWF / Dalberg, 2023 (via WWF Africa). https://africa.panda.org/?46242%2FLifetime-cost-of-plastic-10-times-higher-for-low-income-countries-than-rich-ones-revealing-crippling-inequities-in-plastics-value-chain — The lifetime cost of plastic is about US$150/kg in low- and middle-income countries versus US$19/kg in high-income countries, despite far lower per-capita use — the cost of inaction falls hardest where waste systems are weakest.
46. Breaking the Plastic Wave: A Comprehensive Assessment of Pathways Towards Stopping Ocean Plastic Pollution — Pew Charitable Trusts & SYSTEMIQ, 2020 (via University of Plymouth). https://www.plymouth.ac.uk/news/university-expert-contributes-to-global-report-into-plastic-threats-to-the-ocean — Ocean plastic flow was ~11 Mt/yr and would reach ~29 Mt/yr by 2040 without action, but a system change using existing technologies could cut it by more than 80%.
47. "Evaluating scenarios toward zero plastic pollution" — Lau et al., Science, 2020. https://pubmed.ncbi.nlm.nih.gov:443/32703909/ — The peer-reviewed companion to entry 46: applying all feasible interventions cuts plastic pollution 78% versus business-as-usual in 2040 — yet 710 Mt would still enter aquatic and terrestrial ecosystems cumulatively, so delay locks in a large legacy.
48. Turning off the Tap: How the world can end plastic pollution and create a circular economy — UNEP, 2023 (via UN News). https://www.un.org/en/delegate/new-un-%E2%80%98roadmap%E2%80%99-shows-how-drastically-slash-plastic-pollution — Plastic pollution could be cut 80% by 2040 with existing technologies via reuse, recycling and reorienting materials — the savings and delay costs are quantified in entry 71.
49. Global Plastics Outlook: Policy Scenarios to 2060 — OECD, 2022 (summary via SGS). https://www.sgs.com/en-ao/news/2024/03/cc-q1-2024-meeting-the-challenge-of-sustainability-in-plastics — On the baseline path, plastics use triples by 2060, leakage doubles to ~44 Mt/yr, and the plastic already accumulated in rivers and oceans more than triples from 140 Mt to 493 Mt.
50. "Can we clean up the oceans?" (expert summary) — XRAY Magazine / New Scientist reporting, n.d. https://xray-mag.com/content/can-we-clean-oceans — Journalism/expert opinion, not a cost study: researchers quoted argue interception at source and on coasts is more effective and cost-efficient than offshore cleanup — 5 Gyres' Eriksen calls ocean-only cleanup "mopping the floor while the tap is still running". No peer-reviewed head-to-head $/tonne river-vs-ocean trial was found (see Could Not Verify).

6. THE NEXT TEN YEARS AND THE IRREVERSIBILITY LINE (11 entries)

51. UNEP assessment announcement: "Comprehensive assessment on marine litter and plastic pollution confirms need for urgent global action" — UNEP press release for From Pollution to Solution, 2021. [verified live] http://www.unep.org/en/news-and-stories/press-release/comprehensive-assessment-marine-litter-and-plastic-pollution — On current trends, plastic leakage into aquatic ecosystems is projected to more than double by 2030, and the annual flow into marine areas to nearly triple by 2040 to 23–37 Mt/yr — roughly 50 kg of plastic per metre of the world's coastline per year.
52. Borrelle et al. 2020 (entry 8) — the 2030 line in one number: even if every current government commitment is met, up to 53 Mt/yr enters aquatic ecosystems by 2030; efforts so far are outpaced by waste growth.
53. OECD 2022, Policy Scenarios to 2060 (entry 49) — the long line: stocks already in rivers and oceans grow from 140 Mt to 493 Mt by 2060 on the baseline, i.e. the accumulated problem more than triples even though annual leakage "only" doubles.
54. Geyer et al. 2017 (entry 2) — on current trends roughly 12,000 Mt of plastic waste will be in landfills or the natural environment by 2050 — the reservoir from which future leakage and fragmentation continue.
55. "The global threat from plastic pollution" — MacLeod, Arp, Tekman & Jahnke, Science, 2021. https://pubmed.ncbi.nlm.nih.gov/34210878 — The irreversibility statement to quote: plastic accumulating where natural mineralisation is slow and engineered remediation is improbable is "poorly reversible" — if harms emerge there, they will be practically irreversible; the rational response is to rapidly cut emissions and virgin plastic production.
56. "Outside the Safe Operating Space of the Planetary Boundary for Novel Entities" — Persson et al., Environmental Science & Technology, 2022 (summary). https://sustainability.unesco-floods.eu/?p=163 — Humanity is already outside the safe planetary boundary for novel entities including plastics, because production and releases are growing faster than society's capacity to assess and monitor them — and because of persistence, the threat continues even after releases fall.
57. "Marine plastic pollution as a planetary boundary threat – The drifting piece in the sustainability puzzle" — Villarrubia-Gómez, Cornell & Fabres, Marine Policy, 2018. https://www.mendeley.com/catalogue/bd991275-4d7c-39c8-9aee-c491911ab7a3/ — Marine plastic already meets two of the three conditions for a planetary-boundary threat — irreversibility and global ubiquity; the third (demonstrated widespread Earth-system disruption) is not yet proven, and the authors say so.
58. Managing the systemic use of chemicals in Europe — European Environment Agency, 2023. https://www.eea.europa.eu/en/analysis/publications/managing-the-systemic-use-of-chemicals — The EEA's plain statement of the mechanism: plastic does not chemically degrade in the environment but fragments, so "once ecosystems are polluted with microplastics, it is virtually impossible to remove them" (citing Villarrubia-Gómez et al. 2018).
59. "Seafloor microplastic hotspots controlled by deep-sea circulation" — Kane et al., Science, 2020 (via University of Manchester). https://www.manchester.ac.uk/about/news/scientists-find-highest-ever-level-of-microplastics-on-seafloor/ — Deep-sea currents concentrate up to 1.9 million microplastic pieces per square metre of seafloor, in the same places they deliver food and oxygen — so biodiversity hotspots are likely microplastic hotspots; floating surface plastic is under 1% of what enters the ocean, and the deep-sea sink is beyond any realistic cleanup.
60. "Risk assessment of microplastics in the ocean: Modelling approach and first conclusions" — Everaert et al., Environmental Pollution, 2018. https://biblio.ugent.be/publication/8760883 — Floating microplastic concentrations are projected to rise ~50-fold by 2100, and sedimented microplastics are expected to exceed the authors' derived safe level in the second half of this century — with the honest counterweight that average floating concentrations are not projected to exceed their safe level by 2100; polluted hotspots already do.
61. Kikaki et al. 2020 and Healthy Reefs 2024 (entries 13, 20) — the regional timescale: Caribbean-bound river plastic pulses every rainy season into a reef system already graded "poor" overall, so each decade of delay adds legacy damage to a reef with little resilience left.

7. THE SOLUTION, AND THE PROOF IT WORKS (19 entries)

System change works on paper — and its components work in measured practice:

62. Pew/SYSTEMIQ 2020 (entry 46) — the headline proof-of-concept: with existing technologies and a system change (reduce, reuse, collect, recycle, safely dispose), the annual flow of plastic into the ocean can be cut by more than 80% by 2040.
63. Lau et al. 2020 (entry 47) — the peer-reviewed version: all feasible interventions together cut pollution 40% versus 2016 rates and 78% versus 2040 business-as-usual; the modelled gains come overwhelmingly from upstream reduction, collection and disposal — not from ocean cleanup.
64. Turning off the Tap — UNEP, 2023 (detailed summary via SAICM Knowledge). https://saicmknowledge.org/articles/unep-report-identifies-market-shifts-needed-reduce-plastic-pollution — The economics of acting: shifting to a circular economy by 2040 would save $1.27 trillion in costs and recycling revenues, avoid a further $3.25 trillion in health, climate, air-pollution, marine-ecosystem and litigation costs, and create a net 700,000 jobs, mostly in low-income countries.
65. Delay cost, same report — UNEP, 2023 (via Chronicle India summary). https://www.chronicleindia.in/current-affairs/8938-turning-off-the-tap-how-the-world-can-end-plastic-pollution-and-create-a-circular-economy — A five-year delay in making those shifts adds roughly 80 Mt of plastic pollution by 2040 and raises the cost of the transition — the quantified case for "now, not later".

Interception beats open-ocean cleanup — the comparative evidence:

66. "Modeling marine surface microplastic transport to assess optimal removal locations" — Sherman & van Sebille, Environmental Research Letters, 2016 (via Phys.org). https://phys.org/news/2016-01-ocean-plastics-focus-coasts-great.html — Modelling of collector placement: putting collectors near coasts removes more microplastic and prevents more harm to wildlife and ecosystems than putting them in the Great Pacific Garbage Patch.
67. Hohn et al. surface-cleanup assessment — Leibniz Centre for Tropical Marine Research / Jacobs University, 2020 (via ScienceDaily). https://WWW.Sciencedaily.com/releases/2020/08/200804085923.htm — Even 200 ocean surface-cleanup devices running without downtime for 130 years would remove only ~44,900 tonnes — just over 5% of floating plastic — at a relatively high cost per unit; by contrast, completely halting river inputs with barriers in key polluting rivers could prevent most of the pollution otherwise predicted over the next three decades.
68. "How much innovation is needed to protect the ocean from plastic contamination?" — Cordier & Uehara, Science of the Total Environment, 2019. http://www.ncbi.nlm.nih.gov/pubmed/30921712 — Cleanup-only maths: cutting the ocean plastic stock 25% below 2010 levels by 2030 would mean removing 135 Mt at €492–708 billion (~1,924 Ocean-Cleanup-scale projects); a combined portfolio of solutions could instead return the stock to 2013 levels (94 Mt) by 2030 — technology alone is not sufficient, and not the cheapest path.
69. "Most debris removed from a waterway by a trash interceptor" (Mr. Trash Wheel, Baltimore) — Guinness World Records, 2023. https://www.guinnessworldrecords.com/world-records/645857-most-debris-removed-from-a-waterway-by-a-trash-interceptor — Independently certified interception at a river mouth: 1,832 tonnes removed from the Jones Falls between May 2014 and December 2023 (a mix of natural and man-made debris; operator sampling estimates ~1.25 million plastic bottles among it).
70. Trash interception (Mr. Trash Wheel family) — Waterfront Partnership of Baltimore (operator), n.d. https://www.mrtrashwheel.com/trash-interception — The four Baltimore trash wheels together collect roughly 500 tons of trash a year before it reaches the harbour and Chesapeake Bay, ~90% of it washed in by rain — interception works precisely where rivers concentrate the flow.
71. Chulalongkorn University / Ocean Cleanup Chao Phraya River research, 2021–2024 — via Thailand4 news summary, 2025. https://www.thailand4.com/en/1446275 — Preliminary, university-partner (not yet peer-reviewed): camera/AI monitoring at three Bangkok bridges found the solar Interceptor "significantly reduces" waste flowing to the sea, collecting up to 6–7 tons over 2–3 days depending on weather.

Policy works — measured reductions, not pledges:

72. Carrier bag charge data for England — UK Parliament written Q&A (Defra data), 2022. https://questions-statements.parliament.uk/written-questions/detail/2022-01-17/105785 — England's 5p charge (2015) produced a 95% reduction in single-use bag sales at major retailers, and retailers had donated nearly £190 million from the charge to good causes; later Defra figures report a 98% fall, from 7.6 billion bags in 2014 to 133 million.
73. "UK Fee Leads to 80 Percent Drop in Plastic Bag Litter on Beaches" — Yale Environment 360, reporting Marine Conservation Society surveys, 2024. https://e360.yale.edu/digest/uk-plastic-litter-bag-charge?__s=tnzk1yo25hvw9n2qdiq5 — The outcome in the environment itself: plastic bags found on UK beaches fell 80% in a decade, from 5 per 100 m of coastline in 2014 to 1 per 100 m, which the MCS attributes to the bag charges.
74. "International policies to reduce plastic marine pollution from single-use plastics (plastic bags and microbeads): A review" — Xanthos & Walker, Marine Pollution Bulletin, 2017. https://old.pame.is/document-library/desktop-study-on-marine-litter-library/additional-documents/552-xanthos-2017-international-policies-to-reduce/file — Ireland's 2002 levy caused an immediate ~90% cut in bag use (328 → 21 bags per person); Wales' levy cut use 71% in three years — with the caution, from the same review, that South Africa's levy effect eroded as shoppers got used to paying, so charges must be maintained or raised.
75. "Why Banning Plastic Bags Doesn't Work as Intended" (Taylor 2019, California) — Chicago Booth Review, 2019. https://www.chicagobooth.edu/review/why-banning-plastic-bags-doesnt-work-intended — Honest partial-success evidence: California's local bans cut disposable-bag plastic by ~40 million lb/yr, but purchases of (thicker) trash bags rose ~12 million lb/yr, offsetting ~29% — the net reduction is real, and policy must be designed against substitution.
76. "Deposit Return Schemes in Europe: How They Compare" — TOMRA, n.d. https://www.tomra.com/en-ie/reverse-vending/media-center/feature-articles/deposit-return-schemes-europe — Industry source (TOMRA sells reverse-vending systems — flag the interest), reporting scheme-operator data: Germany's return rate exceeds 98% and Norway's is 92%; Lithuania jumped from under 34% to 92% within two years of launching its scheme; Latvia recorded a 61% fall in plastic containers in coastline litter two years in.

Removing the pressure pays — recovery and avoided-loss evidence:

77. NOAA Economic Loss page (entry 43) — the local business case in reverse: near-zero debris scenarios are worth hundreds of millions in tourism, and derelict-gear removal is worth tens of millions in crab harvest, in single US regions alone.
78. "The Dilemma of Derelict Gear" — Scheld, Bilkovic & Havens, Scientific Reports, 2016. https://pubmed.ncbi.nlm.nih.gov/26790394/ — Removing 34,408 derelict crab pots from Chesapeake Bay was followed by an estimated +27% harvest worth US$21.3 million versus the no-removal counterfactual, and the model suggests US$831 million/yr could be recovered globally by removing under 10% of derelict pots and traps — magnitude contested: a Chesapeake Bay stock-assessment review questioned the underlying report's methodology, and NOAA cites a larger programme total ($33.5m); the direction — removal pays for itself in harvest — is the defensible claim.
79. Healthy Reefs 2024 (entry 20) — the only regional recovery signal found: the Mesoamerican Reef's 2024 report card was its first improvement in five years under sustained management — but the grade remains "poor", and the improvement cannot be attributed to plastic removal specifically. No study was found that removed plastic alone and measured reef or fish recovery — see Could Not Verify.
80. Lamb et al. 2018 (entry 28) — the reef logic in one line, in the authors' own conclusion: because disease likelihood collapses when coral is not touching plastic, reducing plastic entering the ocean directly reduces disease-associated coral mortality — prevention is the intervention the disease science points to.

Flagged / Contested Claims (do not publish as settled facts)

1. "More plastic than fish by 2050" (Ellen MacArthur Foundation/WEF 2016) — AAP FactCheck verdict: Unproven. It is a scenario comparing projected plastic weight (850–950 Mt) with an estimated fish biomass (812–899 Mt) that AAP says significantly underestimates global fish stocks. Present only as a business-as-usual warning scenario.
2. "Humans eat a credit card (5 g) of plastic a week" — Refuted on re-analysis: Pletz (2022) found "severe errors" and estimated ~one credit card per ~23,000 years; Mohamed Nor et al. (2021) modelled median intake in micrograms per week. Do not use (entry 40).
3. Motagua = "2% of global ocean plastic" / "world's most polluting river" — A single-source operator/advocate claim built on The Ocean Cleanup's ~20,000 t/yr estimate. Tonnages conflict across sources (~8,000 t/yr Guatemala environment ministry via 4ocean; ≥8,500 t/yr waste via ICSF; 20,000 t/yr via Ocean Cleanup/Kia), and against Meijer's global riverine total (0.8–2.7 Mt/yr) the share is ~0.7–2.5%. In Meijer's peer-reviewed ranking the top river was the Pasig (Philippines), not the Motagua. Publish a range with attribution, never the ranking.
4. Ghost gear "640,000 tonnes/yr" and "10% of ocean waste" — Legacy FAO/UNEP figures repeated in FAO's 2021 feature, but the underlying 2009 FAO/UNEP report states its data do not allow global estimates. Richardson et al.'s loss rates (6% of nets, 9% of traps, 29% of lines per year) are the defensible numbers.
5. "90% of seabirds have eaten plastic" — Wilcox et al. 2015 is a model-standardised estimate; Kühn & van Franeker (2020) explicitly warn that species-level records are routinely misworded as individual prevalence. Quote with "model estimates".
6. Population-level harm to marine megafauna — Senko et al. 2020: individual harm proven, direct population-level evidence absent over 50 years of study. Do not claim proven population declines caused by plastic alone.
7. Microplastics and human health — Established: exposure via food, water and air, and detection in stool, placenta (small pilot) and blood. Not established: any causal disease effect in humans at current environmental levels. WHO (2019): no apparent risk on limited data — not proof of safety.
8. River-concentration models disagree — Schmidt 2017 (top 10 rivers = 88–95%) vs Lebreton 2017 (top 20 = 67%) vs Meijer 2021 (>1,000 rivers = 80%). Use Meijer as the current peer-reviewed synthesis and disclose that these are models with wide ranges (global riverine totals span 0.41–4 Mt/yr across studies).
9. All headline money figures are models — $13bn/yr (UNEP 2014, authors call it an underestimate), $3,300–$33,000/tonne (Beaumont, "conjectured"), $3.7tn lifetime (WWF/Dalberg, ±$1tn), $1.27tn/$3.25tn savings (UNEP 2023 scenario). Label method and range every time; none is a measured expenditure or a guaranteed saving.
10. Interception effectiveness is thinner than interception tonnage — Certified/operator tonnages (Mr. Trash Wheel, Interceptors) prove devices capture plastic; peer-reviewed, independently monitored capture-efficiency studies for river interceptors are scarce, and the Chao Phraya efficiency results are preliminary university-partner findings, not yet a peer-reviewed paper. Ocean Cleanup removal totals (~tens of thousands of tonnes to date, per secondary summaries) equal only a few percent of one year of river inflow — cleanup complements prevention; it cannot substitute for it.
11. Scheld et al. derelict-pot dollars — The peer-reviewed paper reports +$21.3m; NOAA reports +$33.5m for the wider programme; a stock-assessment committee review disputed the methodology. Use the direction, hedge the dollars (entry 78).
12. Everaert threshold nuance — The same risk assessment often cited for microplastic danger projects that average floating concentrations stay below its derived safe level to 2100. The irreversibility case rests on accumulation, fragmentation, sediments and hotspots — not on a claim that the whole ocean crosses a toxicity threshold by a set date. No source supports a single dated "point of no return" for ocean plastic; the defensible statement is MacLeod's: damage in accumulation zones becomes practically irreversible, and every year of delay adds stock that cannot be retrieved.

Could Not Verify

• No peer-reviewed head-to-head cost-per-tonne comparison of river interception vs open-ocean cleanup was found. The comparative case (entries 66–68) is built from placement modelling (Sherman & van Sebille), a surface-cleanup impact model (Hohn et al.) and a system-dynamics cost model (Cordier & Uehara) — strong convergent evidence, but not a field trial with measured $/tonne for both approaches.
• No study found that removed plastic alone and measured ecosystem recovery (coral, fish, reef) attributable to that removal. Recovery evidence is indirect: derelict-pot removal and fishery gains (Scheld), reserve/disease correlations (Lamb), and a regional report-card improvement (Healthy Reefs 2024) that cannot be attributed to plastic.
• Motagua tonnage and global share remain unresolved across operator, ministry and NGO sources (8,000–20,000 t/yr); no peer-reviewed Motagua-specific plastic flux measurement was found — Kikaki et al. 2020 is the closest peer-reviewed source and does not give a Motagua flux total.
• Roatán (Honduras) mangrove litter study (Zuniga-Lopez et al., via JoVE Visualize: 3,417 items, 98.7% plastic, litter found in a deceased American crocodile) — the publication year was not shown in the source captured, so it was excluded rather than cited with a guessed year.
• Thompson et al. 2004 ("Lost at Sea: Where Is All the Plastic?", Science — the paper that coined "microplastics") — no clean, verifiable URL was captured in the sources read, so it was excluded rather than linked with a constructed URL.
• Exact publication years for a few undated institutional web pages (UNEP riverine interactive, EEAS Honduras post, ICSF news item, 4ocean and EcoHubMap pages, TOMRA comparison, Mr. Trash Wheel operator page) are given as "n.d." — the pages themselves carry no visible date in the sources read.

Sources

All read/searched on 2026-10-28. [verified live] = page opened and read in the research browser; all others are index (search-result) sources. Full working notes: notes/consolidated-sources.md (Sections 1–5) and notes/sections-6-7-sources.md (Sections 6–7).

Verified live: - WHO, Microplastics in drinking-water (2019) — https://www.who.int/publications-detail-redirect/9789241516198 - UNEP, From Pollution to Solution press release (2021) — http://www.unep.org/en/news-and-stories/press-release/comprehensive-assessment-marine-litter-and-plastic-pollution - NOAA Marine Debris Program, "Economic Loss" — https://marinedebris.noaa.gov/why-marine-debris-problem/economic-loss - Kikaki et al., Remote Sensing (2020) — https://www.mdpi.com/2072-4292/12/11/1727

Index (selected — every entry above carries its own URL in-line): PubMed records for Jambeck 2015, Geyer 2017, Borrelle 2020, Duncan 2019, Koelmans 2019, Smith 2018, Vethaak & Legler 2021, Beaumont 2019, Lau 2020, MacLeod 2021, Scheld 2016 and Cordier & Uehara 2019; PLOS ONE (Eriksen 2014); UFZ publication index (Schmidt 2017; Meijer 2021); Roger Williams University repository (Lebreton 2018); ResearchBunny (Cottom 2024); OECD (2022 Outlook); GRID-Arendal (UNEP 2021); WEF and AAP FactCheck (Ellen MacArthur claim); UNEP interactives (riverine plastic); ICSF; El Universal; EEAS; Classic Kia reprint (Ocean Cleanup/Kia); EcoHubMap; ICRI (Healthy Reefs 2024); 4ocean; University of Plymouth (Gall & Thompson 2015; Pew 2020); ScienceDaily (Wilcox 2015; Hohn 2020); Wageningen University PDF (Kühn & van Franeker 2020); ResearchGate (Wilcox 2018); ACAP (Senko 2020); Cornell CALS (Lamb 2018); FAO (Macfadyen 2009; ghost-fishing feature 2021); NOAA repository (Richardson 2019); Phys.org (Richardson 2019 loss rates; Sherman & van Sebille 2016); ACS (Cox 2019); Università Politecnica delle Marche repository (Ragusa 2021); VU Amsterdam report (Leslie 2022); FirstCheck (credit-card claim); UNEP press release 2014 (Valuing Plastic); WWF/Dalberg 2021 and 2023; UN News and SAICM Knowledge and Chronicle India (UNEP Turning off the Tap 2023); SGS summary (OECD 2060); XRAY Magazine (cleanup experts); UNESCO-floods sustainability summary (Persson 2022); Mendeley catalogue (Villarrubia-Gómez 2018); European Environment Agency (chemicals management, 2023); University of Manchester (Kane 2020); Ghent University bibliography (Everaert 2018); UK Parliament Q&A (Defra bag-charge data, 2022); Yale Environment 360 (MCS beach surveys, 2024); PAME-hosted PDF (Xanthos & Walker 2017); Chicago Booth Review (Taylor 2019); TOMRA (deposit return schemes — industry source); Guinness World Records and mrtrashwheel.com (Baltimore trash wheels); Thailand4 (Chulalongkorn/Ocean Cleanup Chao Phraya research).