| Ziajahromi et al., 2021 [128] | n.a | 22.1 × 106 to 133 × 106 per day | >25 µm | n.a | 99.8% - 98.2% | Visual Observation and FT-IR | Australia |
| Wei et al., 2020 [129] | 430 - 2154 MP/m3. | 430 - 2154 MP/m3 | 0.0308 - 0.1 mm | RD-WWTFs | 84% | Micro-Raman spectroscopic | China (Hangzhou) |
| Petroody et al., 2020 [130] | 12,667 MP/m3 | 12667 ± 668, 3514 ± 543 and 423 ± 44.9 MP/m3 | 37 - 500 µm | n.a | 96.7% | Visual Observation and Micro-Raman spectrometry | Iran (Sari) |
| Edo et al, 2020 [109] | n.a | 12.8 ± 6.3 MP/L | 25 to 104 µm | Primary and secondary | >90% | Visual inspection and FT-IR | Spain (Madrid) |
| Ben-David et al., 2021 [131] | 28.28 MP/L | 1.97 MP/L | ≥20 μm | Primary, Secondary and tertiary | 97% | optical microscopy, SEM and μ-Raman microscopy | Israel (Karmiel) |
| Tagg et al., 2020 [117] | n.a | 1.5 MP/L | 392 μm | Primary, Secondary and tertiary | 76.9% | micro-FT-IR | UK (East Midlands) |
| Akarsu et al., 2020 [132] | 1.1 and 3.6 MP/L | 0.9 MP/L | 1057 and 1095 | Primary, Secondary and tertiary | 55% - 97% | FT-IR | Turkey Mersin Bay |
| Bayo et al., 2020 [110] | 15.70 MP/L | 13.04 MP/L | 400 to 600 μm | Primary | 90.3% | Visual inspection and FT-IR | Spain (Cartagena) |
| Naji et al., 2021 [133] | 74 (±11.01, SD) and 67 (±18.35, SD) MP 35/L | 70.66 MP/L | > 250 mm | Primary and secondary | n.a | SEM and X-ray EDX | Iran (Bandar Abbas City) |
| Tang et al., 2021 [136] | 23.3 MP/L and 80.5 MP/L | 23.3 to 7.9 MP/L | 0.636 to 0.803 | Primary and secondary | 66.1% and 62.7%, | Raman spectroscopy | China (Wuhan City) |
| Park et al., 2020 [137] | 10 to 470 MP/L | 10 to 470 MP/L | 45 μm to 5 mm | Primary, Secondary and tertiary | 98.7% - 99.99% | FT-IR | Korea |
| Rajala et al., 2020 [138] | n.a | 0.1 mg/L, 6.7 mg/L (used) | 1 μm and 6.3 μm | Secondary | 99.4% | coagulation/ flocculation | Finland |
| Nguyen et al., 2021 [139] | n.a | n.a | >45 μm | Primary, Secondary and tertiary | 80% | Microscopic and FT-IR | Korea (Seoul) |
| Alvim et al., 2020 [140] | n.a | 11.1 MP/L | <1 mm | Primary, Secondary | n.a | Visual/ µ-ATR-FTIR | Spain (Valencia) |
| Yuan et al., 2020 [141] | n.a | 10.30 MP/L, 6.10 MP/L | 141 to 665 μm | Primary, Secondary and tertiary | 97.67% and 98.46% | n.a | China (Nanjing) |
| Pittura et al., 2021 [142] | (12,170,000 MP/h) 3.6 MP/L | 1,730,000 MP/h | <1 mm | Primary, Secondary | 94% | Stereomicroscope and µ FT-IR | Italy |
| Zou et al., 2020 al. [143] | n.a | 1.719 ± 1.035 MP/L | n.a | n.a | n.a | n.a | China (Guangzhou) |
| Mak et al., 2020 [134] | n.a | 10,816 MP/m3 | 90 to 189 μm | Primary, Secondary | 86.4% |
| Hong Kong (Victoria Harbor) |