Table 2.

Overview on some currently discussed definitions of micro- and nanoplastics.

Organisation	Definition of Microplastics (MPs) and Nanoplastics (NPs)	Source
European Food Safety Authority (EFSA)	MPs: Heterogeneous mixture of differently shaped materials referred to as fragments, fibres, spheroids, granules, pellets, flakes or beads, in the range of 0.1–5000 μm (100 nm–5 mm) NPs: Material with any external dimension in the nanoscale or having internal structure or surface structure in the nanoscale (0.001–0.1 μm = 1–100 nm)	European Food Safety Authority EFSA (2016)
European Chemicals Agency (ECHA)	MPs: Consisting of solid polymer-containing particles, to which additives or other substances may have been added, and where ≥ 1% w/w of particles have (i) all dimensions 1 nm ≤ x ≤ 5 mm, or (ii), for fibres, a length of 3 nm ≤ x ≤ 15 mm and length to diameter ratio of >3	ECHA (2019) EC-SAM (2019)
International Standardization Organization (ISO)	MPs: Solid plastic particles insoluble in water with any dimension between 1 mm and 5 mm (large MP)/1 μm and 1000 μm (MP) NPs: plastic particles smaller 1 μm	ISO (2020)
United Nations (UN)	MPs: Particles in the size range 1 nm to <5 mm.	UN-GESAMP (2015)
European Academies	MPs and NPs: Tiny plastic particles of mixed shapes and sizes below 5 mm.	SAPEA (2019)
US National Oceanic and Atmospheric Administration	MPs: Any type of plastic fragment that is less than 5 mm in length	US NOAA (2009)