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Updated: Dec 3, 2025
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Sampling, Sorting, and Characterizing Microplastics in Aquatic Environments with High Suspended Sediment Loads and Large Floating Debris
Published on: July 28, 2018
16.6K
Semi-automated analysis of microplastics in complex wastewater samples
Alice A Horton1, Richard K Cross2, Daniel S Read2
1UK Centre for Ecology & Hydrology, Maclean Building, Benson Lane, Crowmarsh Gifford, Wallingford, Oxfordshire, OX10 8BB, UK; National Oceanography Centre, European Way, Southampton, SO14 3ZH, UK.
Environmental Pollution (Barking, Essex : 1987)
|October 29, 2020
Summary
Wastewater treatment works (WwTWs) remove 99.8% of microplastics, but sludge contains high concentrations. This study highlights quality control for accurate microplastic analysis in environmental samples.
Area of Science:
- Environmental Science
- Analytical Chemistry
- Polymer Science
Background:
- Microplastic pollution poses risks to the natural environment.
- Accurate quantification of microplastic inputs and discharges is crucial for risk assessment.
- Wastewater treatment works (WwTWs) are significant pathways for microplastics entering aquatic ecosystems.
Purpose of the Study:
- To quantify microplastic concentrations in WwTW influent, effluent, and sludge.
- To evaluate the removal efficiency of microplastics by various WwTW treatment processes.
- To establish robust quality control measures for microplastic analysis in complex environmental matrices.
Main Methods:
- Collection of composite influent, effluent, and sludge samples from eight UK WwTWs over 24-hour periods and multiple occasions.
- Analysis of microplastics ≥25 μm using micro-Fourier-transform infrared (micro-FTIR) spectroscopy.
- Implementation of procedural blanks to determine limits of detection (LOD) and quantification (LOQ), and for blank corrections.
Main Results:
- Microplastic concentrations in influent ranged from 955 to 17,214 particles/L, and in effluent from 2 to 54 particles/L.
- An average microplastic removal rate of 99.8% was achieved by the WwTWs studied.
- Quantifiable microplastic concentrations in sludge ranged from 301 to 10,380 particles/g dry weight, with polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET) being the most common polymers.
Conclusions:
- WwTWs are highly effective at removing microplastics from wastewater, but sludge represents a concentrated reservoir.
- The analytical method employed provides more accurate and higher microplastic concentration data than previously reported.
- Stringent quality control and blank correction are essential for reliable microplastic quantification in environmental samples.
