Primary and secondary

China

(Beijing)

681.46 μm   

95.16

Microscopy and FT-IR

Yang et al., 2019 [121]

Primary, secondary and tertiary

Italy

(Italy)

0.5 - 0.1 mm

113,000a

FT-IR

Magni et al., 2019 [115]

Secondary

Australia

(New South Wales, Hunter Region)

>1.5 μm to >1 mm

7.91 ± 0.44 MP/L (in activated sludge

Visual sorting and ATR-FT-IR

Raju et al., 2020

[144]

Primary and secondary

Italy

<1 mm

1.67 MP/g TS in the Sludge, 5.3 MP/g TS in the AerWAS and 4.74 MP/g TS dewatered sludge

Stereomicroscope and µ FT-IR

Pittura et al., 2021 [142]

Primary and secondary

Spain

(Valencia)

<1 mm

280 MP/Lof activated sludge

μ-ATR-FT-IR/ATR-FT-IR

Alvim et al., 2020 [140]

Primary and secondary

Iran

(Bandar Abbas City)

>250 µm

328.50 (±56.42, SD) MP/50 g dw and 278.4 (±26.87, SD) MP/50 g dw

SEM and X-ray EDX

Naji et al., 2021

[133]

Primary and secondary

Spain

25 to 104 µm

183 ± 84 MP/g (mixed sludge), 165 ± 37 MP/g (dried sludge)

Visual inspection and FT-IR

Edo et al, 2020 [109]