Glossary

A toxic chemical formed when 6PPD, an antioxidant added to tyres to stop rubber cracking, reacts with ozone in air. In 2021 researchers identified it as the cause of mass deaths of coho salmon in urban streams after rain. It has been found in human urine; whether it harms people at those levels is unknown.

Source: Tian et al. 2021, A ubiquitous tire rubber-derived chemical induces acute mortality in coho salmon (Science). See also: tyre wear microplastics 6ppd quinone.

A chemical deliberately added to plastic to change how it behaves: plasticisers to soften it, flame retardants, stabilisers, antioxidants, pigments and more. EU food-contact law defines an additive as a substance intentionally added to achieve a physical or chemical effect and intended to stay in the finished product. Most additives aren't chemically bound to the polymer, so they can leach.

Source: Commission Regulation (EU) No 10/2011, Article 3(7). See also: phthalates explained, black plastic utensils flame retardants, plastic types resin codes 1 7.

An association means two things tend to occur together; causation means one actually produces the other. Observational studies can show associations but can't rule out other explanations, such as diet, income or measurement error. Showing causation usually takes consistent results from different kinds of studies, a plausible mechanism and a dose-response pattern.

See also: microplastics health evidence review, marfella 2024, about.

Plastic made wholly or partly from plants or other biological material rather than oil or gas. It says nothing about what happens at end of life: bio-based PET or polyethylene is chemically identical to the fossil version and doesn't biodegrade, while some fossil-based plastics do. Labels often blur this.

Source: European Commission, Bio-based, biodegradable and compostable plastics. See also: compostable biodegradable bioplastics greenwashing.

Able to be broken down by microbes into water, carbon dioxide and biomass. On its own the word is close to meaningless on a label, because it doesn't say how long, where or under what conditions. 'Biodegradable' carrier bags in a University of Plymouth study could still hold shopping after three years in soil or the sea.

Source: European Commission, Bio-based, biodegradable and compostable plastics. See also: compostable biodegradable bioplastics greenwashing, laundry pods pva plastic biodegrade.

Bisphenol A, a building block of polycarbonate and of epoxy can linings, also used in some till receipts. It acts like oestrogen in the body. In 2023 the EU's food safety agency cut its tolerable daily intake 20,000-fold, to 0.2 nanograms per kg of body weight a day; Germany's risk agency rejects that figure, and the US FDA still calls BPA safe at current levels.

Source: EFSA 2023, Re-evaluation of the risks to public health related to BPA in foodstuffs. See also: bpa bisphenols explained, microwaving plastic containers microwave safe, lang 2008, policy.

Bisphenol S and bisphenol F, chemical cousins of BPA used to replace it, including in 'BPA-free' products and thermal receipts. A 2015 systematic review found their hormonal activity was of the same order of magnitude as BPA's. US survey data from 2013–14 found BPS in 89.4% of urine samples. Swapping one bisphenol for another is a classic regrettable substitution.

Source: Rochester & Bolden 2015, Bisphenol S and F: a systematic review (EHP). See also: bpa bisphenols explained, reusable water bottles travel mugs linings.

The triangle of three arrows that most people read as 'recyclable'. On plastics it often surrounds a resin code, which only says what the plastic is. California's SB 343 bans the symbol on products that don't meet the state's recyclability criteria, for products made after 4 October 2026, though a federal court has barred the state Attorney General from enforcing it while a legal challenge continues.

Source: CalRecycle, SB 343: Accurate Recycling Labels. See also: plastic recycling myth labels, plastic types resin codes 1 7, policy.

An umbrella term, also sold as 'advanced recycling', for processes that break plastic down chemically: pyrolysis and gasification into oils and gases, or depolymerisation of a few sorted plastics back into building blocks. Much of the output can end up as fuel. EU law doesn't count turning waste into fuel as recycling.

Source: Directive 2008/98/EC (Waste Framework Directive), Article 3 definition of recycling. See also: plastic recycling myth labels.

A study that follows a group of people over time, measuring exposures (for example, chemicals in urine or plastic in artery plaque) and then seeing who develops which outcomes. It's one of the stronger kinds of observational study, but it still shows association, not proof of cause.

See also: microplastics health evidence review, marfella 2024, trasande 2022.

Certified to break down in composting within a set time, leaving no toxic residue. 'Industrial' compostable (standards such as EN 13432 or ASTM D6400) needs the heat and conditions of a commercial facility. 'Home' compostable is meant to break down in a garden heap, but in a UK citizen-science project 60% of certified home-compostable items were still clearly visible.

Source: Purkiss et al. 2022, The Big Compost Experiment (Frontiers in Sustainability). See also: compostable biodegradable bioplastics greenwashing, plastic recycling myth labels.

A system where you pay a small refundable deposit on a drinks container and get it back when you return it. Well-run schemes collect a very high share of bottles and cans for high-quality recycling, the EU says. The EU requires them for single-use plastic bottles and metal cans by 2029, with an exemption for countries that separately collected at least 80% of them in 2026.

Source: Regulation (EU) 2025/40 on packaging and packaging waste (PPWR). See also: policy, packaging industry plastic pollution your fault.

Recycling a material into something of lower quality or value that usually can't be recycled again, such as bottles into fleece, carpet or park benches. Much plastic recycling is downcycling, because the polymer degrades and picks up contaminants. It delays the trip to landfill or incineration rather than closing the loop.

See also: plastic recycling myth labels, synthetic clothes shed microplastics.

A chemical that interferes with the body's hormone system, for example by mimicking oestrogen or blocking testosterone, in a way that causes harm. BPA and several phthalates are well-studied examples. Hormones act at tiny concentrations, which is why low doses and timing, especially in pregnancy and early childhood, matter.

See also: bpa bisphenols explained, phthalates explained, microplastics health evidence review.

A policy that makes companies that sell packaging or products pay for, and sometimes run, collecting and recycling them once they're thrown away, instead of leaving the bill to councils and taxpayers. Fees can be set higher for hard-to-recycle packaging. Examples include California's SB 54 and EU rules for packaging and fishing gear.

Source: Regulation (EU) 2025/40 on packaging and packaging waste (PPWR). See also: policy, packaging industry plastic pollution your fault, ocean plastic garbage patch fishing gear cleanups.

Chemicals added to plastics in electronics, furniture foam and building materials to slow fires. Brominated ones, such as PBDEs, persist, build up in people and are restricted in many countries. They turn up in some black plastic kitchenware made from recycled electronics casings, though a much-reported 2024 study's risk estimate was corrected downwards.

Source: Liu et al. 2024, From e-waste to living space (Chemosphere; corrected). See also: black plastic utensils flame retardants, liu 2024, kuang 2018, plastic toys teethers phthalates.

A plastic with fluorine built into its backbone, such as PTFE (Teflon), PVDF and FEP. Industry argues they are stable, 'polymers of low concern'; critics point out that making and disposing of them releases smaller PFAS. Under the OECD's 2021 definition they count as PFAS, and the EU's proposed PFAS restriction includes them.

Source: Lohmann et al. 2020, Are fluoropolymers really of low concern? (ES&T). See also: pfas forever chemicals explained, nonstick pans pfas teflon.

Anything intended to touch food: packaging, containers, cookware, utensils, conveyor belts, can linings, inks and adhesives. In EU law it also covers materials that can reasonably be expected to touch food or transfer their constituents to it. Rules exist for plastics in detail, but many other materials are covered only by general safety duties.

Source: Regulation (EC) No 1935/2004, Article 1. See also: silicone food safe plastic explained, melamine bamboo dinnerware formaldehyde, bpa bisphenols explained, policy.

Two ways of identifying plastic particles by shining light (infrared, or a laser) at them and reading the chemical fingerprint that comes back. Both count and size individual particles. Microscope-based FTIR reaches down to about 10 micrometres; Raman can see particles above about 1 micrometre.

Source: Optical, chemical, and biological detection methods of microplastics and nanoplastics (ACS Measurement Science Au). See also: how microplastics are measured, jenner 2022, montano 2023, li 2020.

Making a product, company or practice look better for the environment than it is: vague words like 'eco' or 'natural', recycling symbols on things nobody recycles, or 'recycled' claims based on paperwork. The EU has banned generic environmental claims unless the trader can show recognised excellent environmental performance (from September 2026), and US guidance on green claims (the FTC Green Guides) dates from 2012.

Source: Directive (EU) 2024/825 on empowering consumers for the green transition. See also: plastic recycling myth labels, melamine bamboo dinnerware formaldehyde, compostable biodegradable bioplastics greenwashing.

A hazard is something that can cause harm; risk is the chance it actually does, which depends on how much you're exposed to and for how long. A chemical can be a serious hazard yet pose low risk at everyday doses, or the reverse. Many scary headlines report a hazard as if it were a measured risk.

See also: microplastics health evidence review, black plastic utensils flame retardants, about.

High-density polyethylene, resin code 2: milk jugs, detergent and shampoo bottles, some food tubs. It is one of the plastics most often accepted for recycling. Some HDPE containers are fluorinated to stop solvents leaking through, a process that can create PFAS that leach into what's inside.

See also: plastic types resin codes 1 7, pfas forever chemicals explained, plastic recycling myth labels.

Latin for 'in glass': experiments on cells or tissues in a dish or test tube rather than in living animals or people (which is 'in vivo'). They are good for spotting possible mechanisms, but doses are often much higher than real exposure and the body's defences are missing, so results don't show harm in people.

See also: microplastics health evidence review, compostable biodegradable bioplastics greenwashing, nonstick pans pfas teflon.

Low-density polyethylene, resin code 4: carrier bags, bread bags, squeezy bottles, some cling film and the thin lining inside paper cups. EPA's 2018 data put US recycling of LDPE packaging at 9.9%. In one lab study, LDPE-lined hot-drink cups released more than a trillion nanoparticles per litre of hot water.

Source: Advancing Sustainable Materials Management: Facts and Figures 2018, Tables and Figures (US EPA, 2020). See also: plastic types resin codes 1 7, zangmeister 2022, tea bags coffee cups microplastics, plastic free food storage cling film.

An accounting method used to label plastic as 'recycled' or 'circular' when recycled and virgin feedstock are mixed in the same plant. The recycled share is booked as credits and can be assigned to particular products, which may physically contain little or none of the recycled material. ExxonMobil's own explainer says as much.

Source: ExxonMobil, Making sense of mass balance. See also: plastic toys teethers phthalates.

Conventional plastic recycling: sorting, washing, shredding and melting plastic into pellets to make new products, without changing its chemistry. It works best for clean, single-type streams like PET bottles. It doesn't remove additives or contaminants, and plastic degrades each time, so much of it is downcycled into lower-grade products.

See also: plastic recycling myth labels, black plastic utensils flame retardants.

A hard thermoset plastic made from melamine and formaldehyde, used for picnic plates, kids' dinnerware and 'bamboo' cups, where ground bamboo is mixed in as filler. Heat, acid and wear increase how much melamine and formaldehyde migrate into food. EU law limits melamine migration to 2.5 mg per kg of food.

Source: Commission Regulation (EU) No 1282/2011 (amending 10/2011). See also: melamine bamboo dinnerware formaldehyde, plastic free kitchen swaps.

A piece of plastic smaller than 5 millimetres. That's the common shorthand, but there's no single agreed lower limit, so studies often report whatever their equipment can see. EU law, in its 2023 restriction on intentionally added microplastics, covers synthetic polymer particles of 5 mm or less in all dimensions and fibre-like particles up to 15 mm long.

Source: Commission Regulation (EU) 2023/2055 (synthetic polymer microparticles). See also: how microplastics are measured, microplastics inside you, microplastics health evidence review, policy.

The transfer of chemicals or particles from packaging, containers or cookware into food or drink. It rises with heat, fat, acidity, contact time and wear, which is why microwaving in plastic, wrapping fatty food in cling film and using scratched containers all increase exposure. Regulators test it using food simulants.

See also: microwaving plastic containers microwave safe, plastic free food storage cling film.

The small building-block molecule that is linked up, over and over, to make a polymer. Ethylene makes polyethylene, styrene makes polystyrene, vinyl chloride makes PVC and BPA is a building block of polycarbonate. Leftover, unreacted monomer can migrate out of the finished plastic, which matters when the monomer is toxic.

See also: plastic types resin codes 1 7, bpa bisphenols explained.

A plastic particle smaller than 1 micrometre (a thousandth of a millimetre). A widely used research guide sets the range at 1 to 1,000 nanometres. Nanoplastics are far more numerous than larger particles but much harder to measure, so numbers for them vary enormously and are easy to contaminate.

Source: Brander et al. 2020, Sampling and QA/QC guide for microplastics (Applied Spectroscopy). See also: how microplastics are measured, brander 2020, qian 2024, zangmeister 2022.

Small plastic pellets, typically 2 to 5 mm across: the raw material that factories melt down to make plastic products. Spills during production and transport put an estimated billions into the ocean every year, and they wash up on beaches. The EU's 2025 pellet-loss regulation calls them the third-largest source of unintentionally released microplastics in the EU, and makes handlers prevent and clean up spills from December 2027.

Source: Regulation (EU) 2025/2365 on preventing plastic pellet losses. See also: policy, ocean plastic garbage patch fishing gear cleanups.

A family of tough synthetic plastics (polyamides) used in clothing, carpets, kitchen utensils, some plastic tea bags and food bags. Nylon fibres are common in indoor air and dust. In one lab study, food-grade nylon bags released far more nanoparticles into hot water than lined paper cups did.

See also: microplastics household dust indoor air, zangmeister 2022, hernandez 2019, tea bags coffee cups microplastics.

Ordinary plastic with additives that make it break up faster when exposed to heat or light. It fragments into microplastics rather than truly biodegrading. EU law defines it as plastic with additives that, through oxidation, lead to fragmentation into micro-fragments or chemical decomposition, and has banned it since July 2021.

Source: Directive (EU) 2019/904, Article 3(3). See also: compostable biodegradable bioplastics greenwashing, policy.

Polyethylene terephthalate, resin code 1: the clear plastic of most drinks bottles and many food trays, and the same polymer as polyester fabric. It's the most recycled plastic in the US, but EPA's latest resin data (2018) put the US recycling rate for PET bottles and jars at only 29.1%, and for all PET packaging at 25.4%.

Source: US EPA, Facts and Figures 2018: Tables and Figures. See also: plastic types resin codes 1 7, plastic recycling myth labels, synthetic clothes shed microplastics, numbers.

Per- and polyfluoroalkyl substances: thousands of man-made chemicals built around carbon-fluorine bonds, which almost nothing in nature can break, hence 'forever chemicals'. Under the OECD's 2021 definition, with a few exceptions, any chemical with at least one fully fluorinated methyl or methylene carbon (no hydrogen, chlorine, bromine or iodine attached) counts, which includes fluoropolymers such as PTFE as well as small molecules like PFOA.

Source: OECD 2021 PFAS terminology report (Food Packaging Forum summary). See also: pfas forever chemicals explained, nonstick pans pfas teflon, herkert 2020, policy.

The two most studied PFAS. PFOA was used to make Teflon and PFOS in Scotchgard and firefighting foam; both persist in blood for years. The WHO's cancer agency classes PFOA as carcinogenic to humans and PFOS as possibly carcinogenic. The US set a 4 parts-per-trillion drinking water limit for each in 2024.

Source: Zahm et al. 2024, Carcinogenicity of PFOA and PFOS (Lancet Oncology, IARC). See also: pfas forever chemicals explained, nonstick pans pfas teflon, boronow 2019.

A family of chemicals used to soften PVC and to make fragrances last, found in flooring, toys, tubing, cosmetics and food processing equipment. They aren't bound into the plastic, so they leach. Several, including DEHP, DBP, BBP and DIBP, interfere with male hormones; the EU has limited those four to 0.1% in most consumer articles since July 2020.

Source: Commission Regulation (EU) 2018/2005 (REACH restriction on four phthalates). See also: phthalates explained, plastic toys teethers phthalates, swan 2005, trasande 2022.

Polylactic acid, a plastic made from fermented plant sugars such as corn starch. It's sold for 'compostable' cups, cutlery and tea bags. PLA breaks down in industrial composting but slowly or barely in home compost, soil or sea, and it is a contaminant in normal plastic recycling. It falls under resin code 7.

See also: compostable biodegradable bioplastics greenwashing, tea bags coffee cups microplastics.

An additive that makes rigid plastic soft and flexible, mainly used in PVC. Phthalates are the best-known family; others include DEHA (used in some PVC cling film), DINCH and DEHT. Plasticisers aren't bound into the plastic, so they move into fatty food, skin and dust, and heat and fat speed this up.

See also: phthalates explained, plastic free food storage cling film, microwaving plastic containers microwave safe.

A hard, clear, shatter-resistant plastic made from BPA, filed under resin code 7. It was used for baby bottles, reusable water bottles and big water-cooler jugs. Worn, scratched or hot polycarbonate releases more BPA. The EU banned it in baby bottles in 2011 and banned BPA in food-contact materials from January 2025, with most transition periods ending in July 2026.

Source: Commission Regulation (EU) 2024/3190 (BPA in food contact materials). See also: bpa bisphenols explained, reusable water bottles travel mugs linings, plastic types resin codes 1 7, policy.

A very large molecule made of many small repeating units chained together. Plastics are synthetic polymers, usually with a carbon backbone, mixed with additives. Not every polymer is a plastic: cellulose, rubber and silk are natural polymers, and silicone is a synthetic polymer with a silicon-oxygen backbone.

See also: plastic types resin codes 1 7, silicone food safe plastic explained.

PP, resin code 5: yoghurt pots, takeaway tubs, bottle caps, many baby bottles and many 'microwave-safe' containers. It's heat-tolerant, but heat still releases particles: a 2020 study found PP baby bottles shed millions of microplastics per litre when prepared with hot water. EPA put US recycling of PP packaging at 2.7% in 2018.

Source: Advancing Sustainable Materials Management: Facts and Figures 2018, Tables and Figures (US EPA, 2020). See also: plastic types resin codes 1 7, baby bottles microplastics formula, li 2020, microwaving plastic containers microwave safe.

PS, resin code 6: rigid in disposable cutlery and yoghurt pots, foamed (EPS, often called Styrofoam) in takeaway boxes, cups and packing. Its building block, styrene, is classed as probably carcinogenic to humans (Group 2A) and can migrate from containers into food. Foam foodware is banned in the EU and several US states.

Source: IARC Monographs Volume 121: Styrene. See also: plastic types resin codes 1 7, policy, microwaving plastic containers microwave safe.

Plastic that is already tiny when it is made or first released: microbeads in cosmetics, pre-production pellets, and particles worn off tyres or shed from synthetic clothes. A 2017 IUCN report estimated that tyre wear made up 28% of primary microplastics reaching the ocean, second only to synthetic textiles.

Source: IUCN 2017, Primary microplastics in the oceans. See also: tyre wear microplastics 6ppd quinone, synthetic clothes shed microplastics, plastic free bathroom floss toothbrush microbeads.

Polytetrafluoroethylene, best known as Teflon: the classic nonstick coating, also used in some dental floss, plumbing tape and waterproof membranes. It's a fluoropolymer, which makes it a PFAS under the OECD's 2021 definition. Germany's risk agency says it starts to break down at around 360 °C, and the fumes can cause a flu-like illness.

Source: BfR FAQ on PTFE-coated cookware (updated 2 July 2025). See also: nonstick pans pfas teflon, pfas forever chemicals explained, luo 2022.

Polyvinyl chloride, resin code 3, often called vinyl. Rigid in pipes and window frames; made soft with plasticisers (often phthalates) for flooring, toys, tubing and some cling film. Its building block, vinyl chloride, is classed by the WHO's cancer agency as carcinogenic to humans (Group 1). PVC is barely recycled.

Source: IARC Monographs Volume 100F: Vinyl chloride. See also: plastic types resin codes 1 7, phthalates explained, plastic toys teethers phthalates, plastic free food storage cling film.

Pyrolysis–gas chromatography–mass spectrometry: a lab method that heats a sample until plastics break into characteristic fragments, then identifies and weighs them. It gives a mass for each type of plastic but destroys the sample and says nothing about particle size or count. Fats in tissue can produce signals that look like polyethylene.

Source: Optical, chemical, and biological detection methods of microplastics and nanoplastics (ACS Measurement Science Au). See also: how microplastics are measured, microplastics health evidence review, rauert 2025, nihart 2025, monikh 2025.

The US EPA's version of a tolerable daily intake: an estimate of a daily oral dose likely to be without appreciable risk of harmful effects over a lifetime, including for sensitive groups. Comparing measured exposure to it is how studies judge whether a level is worrying, which is how a black-utensil flame-retardant study's corrected estimate came out at about 2% of it.

See also: black plastic utensils flame retardants, nonstick pans pfas teflon.

The number from 1 to 7 stamped on plastic items, identifying the type of plastic: 1 PET, 2 HDPE, 3 PVC, 4 LDPE, 5 PP, 6 PS, 7 other. It was never a promise that the item is recyclable. Since 2013 the ASTM standard has specified a plain solid triangle around the number rather than chasing arrows.

Source: ASTM press release on revisions to the Resin Identification Code standard. See also: plastic types resin codes 1 7, plastic recycling myth labels.

Microplastic that forms when bigger plastic breaks down: bottles, bags, nets and packaging cracking and fragmenting under sunlight, heat, waves and wear. Most floating plastic in the sea, by weight, is still large items that slowly become secondary microplastic, which is why catching big debris before it fragments matters.

See also: ocean plastic garbage patch fishing gear cleanups, how microplastics are measured.

A synthetic rubbery polymer whose backbone is silicon and oxygen rather than carbon, used in bakeware, baby teats, lids and seals. It's heat-tolerant and not a conventional plastic, but it isn't inert: leftover siloxanes can migrate into fatty food. EU food-contact law lists silicones as a separate material from plastics and rubbers.

Source: Regulation (EC) No 1935/2004, Annex I. See also: silicone food safe plastic explained, su 2022.

Small ring-shaped silicone molecules. D4, D5 and D6 are used in cosmetics and remain as leftovers in cured silicone, from which they can migrate into fatty food when baked. Under REACH, the EU limits them to under 0.1% in mixtures and wash-off cosmetics (other cosmetics from June 2027), but the rule doesn't cover silicone bakeware or other articles.

Source: Commission Regulation (EU) 2024/1328 (REACH restriction on D4, D5, D6). See also: silicone food safe plastic explained, plastic free food storage cling film.

Plastic designed to be used once and thrown away: bags, straws, cutlery, cups, sachets and most packaging. The EU defines a single-use plastic product as one made wholly or partly of plastic that isn't designed to be refilled or reused for the same purpose. Its 2019 directive banned some of the most littered items.

Source: Directive (EU) 2019/904, Article 3(2). See also: policy, plastic free kitchen swaps, packaging industry plastic pollution your fault.

In EU law, the maximum amount of one named substance allowed to move from a material into food or a food simulant, usually in mg per kg of food. Melamine's is 2.5 mg/kg, for example. A separate overall migration limit caps everything released from a plastic at 10 mg per dm² of surface, roughly 60 mg per kg of food.

Source: Commission Regulation (EU) No 10/2011, Article 3 and recital 26. See also: plastic free food storage cling film, melamine bamboo dinnerware formaldehyde, silicone food safe plastic explained.

An estimate of how much of a substance a person can take in every day for a lifetime without appreciable health risk, given per kilogram of body weight. Agencies usually start from the highest dose that caused no harm in animal or human studies, divided by safety factors. Different agencies can set very different TDIs from the same evidence, as with BPA.

Source: EFSA 2023, BPA re-evaluation (example of a TDI). See also: bpa bisphenols explained, microplastics health evidence review.

A clear, hard copolyester plastic launched by Eastman Chemical in 2007 to replace polycarbonate in water bottles and kitchenware. It is made without BPA. Whether it releases other hormone-active chemicals has been fought over in lab tests and in court; 'BPA-free' doesn't mean free of all leachable chemicals.

See also: reusable water bottles travel mugs linings, bpa bisphenols explained, plastic types resin codes 1 7.

Tiny bits of tyre rubber, often fused with road grit, worn off as vehicles drive, brake and turn. They wash into rivers with rain and blow into the air. A 2017 IUCN report estimated they make up 28% of primary microplastics reaching the ocean. Heavier vehicles and harder driving wear tyres faster.

Source: IUCN 2017, Primary microplastics in the oceans. See also: tyre wear microplastics 6ppd quinone.