Plastics in the Environment

3.9 Plastics in the Environment

3.9.1 Definitions and Scope

1Plastics in the environment refers to plastics that are uncollected, openly dumped or burned, littered or legacy plastics contaminating the natural environment. The leakage of plastic into the environment, whether intentional or accidental, can occur at every stage of the life cycle.

2Uncollected waste: All solid plastic waste that escapes waste management systems (formal and informal).

3Open dumping and burning: Waste that is deliberately discarded in unauthorised, uncontrolled or unmanaged locations without proper containment or treatment by households, businesses or industries. This includes waste that is deliberately set on fire by households, businesses or industries as a means of volume reduction.

4Fly tipping: the deliberate disposal of large items or quantities of litter (e.g., broken refrigerator, single large bag of rubbish) in a random location (Boucher et al., 2020)351

5Littering: incorrect disposal of small, one-off items that are likely not collected by managed waste methods (Velis et al., 2017)362

6Environmental sampling for debris: the process of collecting samples of debris from the environment.

735 Boucher et al., 2020 36 Cottom et al., 2024

8Environmental monitoring of debris: the repeated measurement, observation or assessment of the environment over time. This technique is often used to identify changes or trends over time (GESAMP, 2019).

3.9.2 Why environment data matters

1Plastics in the environment are the end point that the whole life cycle is meant to prevent. Measuring how much plastic reaches land, rivers and the sea shows the scale of leakage, where it comes from, and whether efforts to reduce it are working.

2This data supports several uses: estimating national leakage and mismanaged waste; finding pollution hotspots and priority sites for action; reporting against SDG indicator 14.1.1 on marine litter and the global plastics instrument now being negotiated; and building the evidence base for clean-up and prevention programmes.

3.9.3 Methods for generating environment data

1Data on plastics in the environment can be generated using one or more of the methods summarised in Table 3.12. Because environmental leakage is diffuse and difficult to observe directly, most methods rely on field sampling, repeated monitoring or remote observation rather than administrative records. The methods are grouped by who is most likely to lead or supply the data:

• 2

  Government: official surveys and estimates, including transect or distance sampling of shorelines, structured questionnaires, and estimates of open burning drawn from national greenhouse-gas inventories.

• 3

  Academia and Research: analytical approaches such as material flow analysis that infer environmental leakage from wider production and waste data.

• 4

  Citizen Science: data generated by volunteers, including coastal clean-up records and public reporting of illegal dumping or fly-tipping.

• 5

  Cross-cutting methods: repeated environmental monitoring at fixed sites, which may be led jointly by governments, researchers and volunteers.

• 6

  Technology options: remote-sensing approaches that use satellite or drone imagery to detect and quantify plastic accumulation across large or inaccessible areas.

7Table 3.12. Tools for Generating Data for plastics in the environment

Method	Description	Advantages	Limitations
Government — Transect walk or distance sampling, for open burning and dumping. Example: Das et al. (2018), Nepal.	Systematic transect walks in sampled locations to record instances of open dumping and open burning.	Data can be gathered on waste quantity, composition and burn condition, supporting detailed waste characterisation; values can be extrapolated to calculate incidents per square kilometre over time and identify spatial patterns; creates baseline data for future monitoring.	Labour-intensive, time-consuming and requires trained personnel; may miss incidents outside sampling times or locations; limited access to certain areas.
Government — Surveys and questionnaires. Examples: Pansuk et al. (2018), Thailand; The Ocean Strainer, Sri Lanka.	Systematic collection of data through standardised questionnaires administered to representative samples of households, individuals, businesses or institutions. See Part IV, Surveys.	Regularly reported data can inform the total waste dumped or burned and its frequency or seasonal patterns; official statistics are regarded as more credible; representative sampling; cost-effective for large areas; potential for data collection from diverse stakeholders.	Resource-intensive; may lack product-specific detail and polymer-type information; potential for response bias, especially regarding illegal practices such as open dumping and burning; potential sampling bias, for example difficulty engaging remote communities due to location or language; requires careful questionnaire design.
Government — National greenhouse gas inventory equation (open burning only).	Calculation of emissions related to open burning of plastics or waste using the IPCC 2006 Guidelines for National Greenhouse Gas Inventories. See Part IV.	Standardised methodology; enables comparison between regions and countries; integrates with national greenhouse gas reporting and climate plans or commitments.	Focuses primarily on emissions caused by waste rather than on the waste itself; requires technical expertise to implement.
Academia and research — Material flow analysis.	See Part IV, Material Flow Analysis, for detailed guidance.	—	—
Citizen science — Clean-up collection data. Examples: International Coastal Cleanup; Tangaroa Blue Foundation (Australia); beach-litter citizen-science baseline, East Pacific coast (De Veer et al., 2023).	Participatory events held irregularly where participants, usually volunteers, collect, sort and categorise debris.	Before collected debris is diverted back to formal waste management streams, data can be collected indicating the quantity diverted back to managed waste streams; when methods are co-designed by scientists, researchers and statistics offices, the information can contribute to official national datasets; engaging citizen scientists leads to cost-effective long-term monitoring.	Sampling biases based on cleanup locations, favouring more accessible or popular sites; variable data quality from volunteer collectors, which can be overcome with detailed training and guidance; event organisation, people management and data sorting require human and financial resources.
Citizen science — Surveillance systems and citizen science. Example: UK portal to report fly-tipping or illegal waste dumping.	Surveillance systems or community citizen science groups can patrol known hotspots for open burning and dumping to monitor their instances, quantities and composition.	Engages the community, leading to cost-effective long-term monitoring; can detect incidents in real time; raises public awareness; systems can be as detailed as capacity and resources allow; field officers can further sample reported sites, weighing and categorising waste burned and dumped.	Variable data quality from volunteer or citizen observers, which can be overcome with training and guidance; requires coordination and verification systems; potential barriers to set-up or to accessing reporting technology.
Cross-cutting — Environmental monitoring. Examples: Tangaroa Blue Foundation (Australia); Operation Clean Sweep.	Sampling initiatives that occur periodically at the same site. Information gathered can include quantity, categories and composition of debris collected. See Part IV, Surveys — environmental surveys.	Creates temporal datasets that can be used to identify trends; establishes baseline measurements used to identify debris hotspots and assess the effectiveness of interventions; engaging citizen scientists leads to cost-effective long-term monitoring; digital platforms and mobile applications can streamline reporting; data on debris diverted back to managed waste streams can be captured before disposal.	Methodological inconsistencies between groups — methods should be co-designed by scientists to align with global best practice; variable volunteer commitment affects data continuity; typically limited to accessible public spaces; variable data quality from volunteer observers.
Technology — Remote sensing approaches. Examples: Plastic Litter Project, Marine Remote Sensing Group, University of the Aegean (Greece); riverine plastic monitoring using UAVs, Klang River (Malaysia).	Aerial imagery through openly available satellites or private drones can be used to detect, visualise and quantify geographic areas of open dumping or burning, or large accumulations of plastic. See Part IV, Remote Sensing Approaches.	Existing publicly available libraries of remote sensing data can make these approaches cost-effective; data available over large geographic areas as well as remote or hidden areas; provides temporal and spatial data; particularly useful when on-the-ground sampling is not possible; thermal imagery can detect heat signatures for open burning.	Drones or other private technologies can be costly; resolution, cloud cover and other factors can interfere with accurate data collection; image analysis requires specialised skills; the technology is still in early stages, though with financing and capacity building it has promising potential.

3.9.4 Disaggregating environment data

1As with the other stages, data on plastics in the environment is most useful when broken down. Wherever the source data allows, it should be disaggregated along the following dimensions:

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  Environment: terrestrial (land, soil, roadsides), freshwater (rivers, lakes) and marine (shoreline, sea surface, water column, seafloor). Separating land from water matters for finding sources and for reporting.

• 3

  Leakage pathway: uncollected waste, open dumping and burning, fly-tipping, and littering (as defined in 5.8.1).

• 4

  Size class: macroplastics, mesoplastics and microplastics, since these need different methods.

• 5

  Polymer, item type, location and time, including the most common items found and repeated measurement over time to show trends and hotspots.

6Further detail on these categories is provided in the Disaggregating Data section.

3.9.5 Data challenges and a tiered approach to getting started

1Data on plastics in the environment carries several challenges. Litter is spread unevenly, and results therefore depend heavily on where and when sampling takes place. Methods differ between groups, which makes data hard to compare unless a common protocol is used. Microplastics need specialised sampling and laboratory work. Much of the data comes from volunteers, and training and quality checks are therefore essential. And clean-up data measures what was removed, not the total amount present. Sources should be combined and clearly documented.

2A practical way to begin is to match the method to current data capacity and strengthen it over time:

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  Basic: use existing clean-up and citizen-science records (for example, coastal clean-ups), and estimate leakage from waste data using a recognised method such as plastic-pollution hotspotting.

• 4

  Intermediate: run repeated monitoring at fixed sites using an internationally agreed protocol (for example, the UNEP/IOC or NOAA shoreline methods, and the UNEP guidelines for rivers and lakes), covering both land and water.

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  Advanced: combine field monitoring, remote sensing and modelling in a material flow analysis that estimates leakage by pathway and environment, with routine validation.

6Countries can move up the tiers as capacity grows; at every stage the priority is a transparent, repeatable method and a clear record of where and how samples were taken.

3.9.6 Further materials

• 1

  GESAMP Guidelines for the monitoring and assessment of plastic litter in the ocean (2019) — internationally agreed guidelines for monitoring and assessing marine litter across shorelines, the water column, the sea surface and biota.

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  UNEP/IOC Guidelines on Survey and Monitoring of Marine Litter (2009) - standardised operational protocols for beach, benthic and floating-litter surveys, including rapid methods suitable for community volunteers.

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  Understanding the State of the Ocean: A Global Manual on Measuring SDG 14.1.1, 14.2.1 and 14.5.1 (UNEP, 2021) - guidance on monitoring techniques for reporting on marine-debris SDG indicators.

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  The Marine Plastic Footprint (IUCN) - a science-based framework for estimating the quantities of plastic leaking into the marine environment during the waste stage.

• 5

  GPML Community of Practice on Harmonisation of Monitoring and Assessment of Plastic Pollution - an expert group addressing harmonisation, interoperability and data comparability across life cycle stages.

• 6

  UNEP GPML Digital Platform - country dashboards with plastic-flow data, policy tracking and collaboration tools that consolidate global datasets.

• 7

  Monitoring Plastics in Rivers and Lakes: Guidelines for the Harmonisation of Methodologies (UNEP, 2020) - methods for assessing plastic contamination in freshwater environments, including rivers and lakes.

• 8

  UNEP/IUCN National Guidance for Plastic Pollution Hotspotting and Shaping Action - a framework for identifying leakage hotspots and prioritising interventions along the plastic value chain.

• 9

  Tangaroa Blue Foundation Australian Marine Debris Initiative (AMDI) Database — a free repository and data-collection app for recording marine debris, usable in any region of the world.

• 10

  CSIRO resources on marine debris - survey resources and a Survey Methodology Handbook (available in English and Portuguese).

• 11

  Deep-sea Debris Database (JAMSTEC, 2017) - public access to seafloor imagery from the Pacific, Indian and Atlantic Oceans since 1983.

12Regional tools

• 13

  Marine Debris Monitoring and Assessment Project protocols and datasheets (NOAA) - protocols, field datasheets and quick guides for shoreline monitoring and assessment.

• 14

  European Marine Observation and Data Network (EMODnet) - protocols and internationally endorsed datasets for shoreline, seafloor and sea-surface litter.

• 15

  Guidance on Monitoring of Marine Litter in European Seas (European Commission, 2023) — updated protocols and recommendations to improve the comparability of marine-litter data among Member States.