| Ref. | MP conc. in influents | MP conc. in effluent | Lower size limit for fractionation µm | WWTP type | Retention/ Efficiency | Analytical Method | Country |
| Lares et al., 2018 [95] | 57.6 MP/L | 1.05 part./L | 250 | Primary and secondary | 98.3% | FTIR and Raman Microscope | Finland (Mikkeli) |
| Dyachenko et al., 2017 [97] | n.a | 0.02 part./L | 125 | Primary, secondary and tertiary | n.a. | n.a | USA |
| Mason et al., 2016 [98] | n.a | 0.05 part./L | 125 | 17 WWTPs, Tertiary | n.a. | Microscope | USA |
| Murphy et al., 2016 [90] | 15.70 MP/L | 0.25 part./L | 11 | Secondary | 98.4% | FTIR | UK |
| Carr et al., 2016 [99] | 1.10 × 109/day (681 million L./day) | 0.88 part./m3 | 45 | Secondary and Tertiary | 99.9% | Visual sorting, Microscope FTIR | USA |
| Ziajahromi et al., 2017 [93] | n.a | 0.28 part./L | 25 | Primary, secondary and tertiary | 92% - 99% | ATR-FT-IR | Australia |
| Michielssen et al., 2016 [100] | 367 MP/L | 0.5 MP/L | 20 | Tertiary (AnMBR) | 99.4% | Visual sorting, Microscope | USA (Northfield ) |
| Mintenig et al., 2014 and 2017 [94] [101] | n.a | 0.1 to 10.1 MP/L | 20 | 12 WWTPs: mostly secondary and tertiary | 97% | micro-FT-IR | Germany (Oldenburg) |
| Talvitie et al., 2015 [102] | 610 MP/L | 13.5 MP/L (incl. all textile fibers) | 20 | Primary, secondary and tertiary | 97.6% | Visual sorting, Stereo- microscope | Finland Viikinmäki |
| Talvitie et al., 2017 [114] | 6.9 | 0.005 MP/L | 20 | 4 tertiary WWTPs | 99.9% | Visual sorting, Stereo- microscope | Finland |
| Leslie et al., 2017 [104] | 73 MP/L | 9 to 91 MP/L | 0.7 | 7 WWTPs | 72% | Visual sorting FTIR | Netherlands |
| Browne et al., 2011 [72] | n.a | 1 MP/L | (filtered) | Primary, secondary and tertiary | n.a. | n.a | Australia |
| Dris et al., 2015 [91] | n.a | 14 to 50 MP/L | 100 | Secondary | 83% - 95% | Visual sorting | France |
| Carr et al., 2016 [99] | 1 MP/L | 90 MP/L | 90 - 300 | Primary, secondary and tertiary | 95% - 99% |
| USA |
| Talvitie and Heinonen 2014 [105] | 627 MP/L | 70 MP/L | 20 | n.a | 95.6% | μ-Raman spectroscopy Microscope | Russia |
| Gűndoğdu et al., 2018 [106] | 4,825,697/day | 7.02 MP/L | n.a. | Secondary | 73% | Visual and μ-Raman spectroscopy | Turkey (Seyhan) |
| Gűndoğdu et al., 2018 [106] | 2,040,639/day | 4.11 MP/L | n.a. | Secondary | 79% | Visual and μ-Raman spectroscopy | Turkey (Yűreğir) |