Microplastics + Nanoplastics微塑料 + 纳米塑料 · MNP

Place · Level 3

MP>5mm · NP<1µm · 已检血/胎盘/动脉斑块 · Marfella 2024 NEJM 硬终点 · 减暴露≫排毒

What · sizes · sources · real intake

Stop 1/6

什么 · 大小 · 来源 · 真实摄入量

Microplastics + nanoplastics (MNP, Microplastics + Nanoplastics) was a concept born of 2010s ocean research and has now become a systemic exposure problem.

Size grading (IUPAC + most literature):

Macroplastics: > 5 mm (visible garbage / fishing nets / bottles)Microplastics (MP): 5 mm – 1 µm — visible down to the limit of the unaided eyeNanoplastics (NP): < 1 µm = < 1000 nm — key: can cross membranes and barriersA key shift: the word 'microplastics' is giving way to 'MNP'; the real threat may not be 5 mm fragments but < 100 nm nanoplastics (can enter cells, cross the blood-brain barrier, even enter mitochondria)
Main plastic types (most often detected):

PE (polyethylene) — food bags / caps / toysPET (polyethylene terephthalate) — water bottles / synthetic fiber clothingPP (polypropylene) — food containers / tea bags / baby bottlesPS (polystyrene) — takeout boxes / cup lidsPVC (polyvinyl chloride) — pipes / raincoatsPolyamide / polyester: synthetic clothing (~700,000 fibers released per wash)
Two major sources:

Primary MP: small particles at manufacture (scrubs / cosmetics / detergents — banned in many countries; industrial milling powders)Secondary MP: produced by environmental degradation of macroplastics (UV + mechanical wear + waves) — this is the dominant route
4 major human exposure routes:

1. Food / drinking water (main)

Bottled water: Cox 2019 estimates adults drinking bottled water inhale ~90,000 more particles per year than those drinking tapSeafood: shellfish (eaten whole) / small fish with intestines / shrimp and crab (especially from heavily plastic-polluted waters)Migration from processed-food packaging (especially when heated, oily, or acidic)Salt: sea salt has the highest MPTea bags: a single plastic mesh bag steeped at 80°C releases billions of nano-particles (Hernandez 2019 ES&T)Microwaving plastic containers: a single heating can release millions of particles (Hussain 2023)
2. Respiration

Indoor dust: synthetic carpets + clothing + decoration materials continuously shedTire wear: ~30% of global MP emissions (Kole 2017)Dry-cleaning synthetic clothes: emission peakVianello 2019: a sedentary adult inhales ~11–90 MP / hour
3. Skin + mucosa

Lipstick / sunscreen / body wash microbeads (banned in many countries but still circulating)Skin absorption: weak through intact skin; broken skin / infants / mucosa absorb more easily
4. Medical (newer recognition)

IV infusion: PVC infusion bags + tubing release MP directly into bloodPlastic medical devices: cardiac catheters + dental resins + surgical disposables
Actual intake:

Cox 2019 ES&T estimates adults take in ~39,000–52,000 MP particles per year from food + respirationSenathirajah 2021's 'one credit card (5 g) per week' figure has been controversial — it stacks several upper-bound assumptions and has been criticized by multiple teams as exaggerated; the true lower bound may be < 1 g/weekWHO 2022 report: current exposure levels can't yet be confirmed to have clear health impacts in the general population, but 'insufficient evidence ≠ safety' — so the precautionary principle and active exposure reduction are recommended

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