The primary objective of this study was to inform the UK and Irish water companies on the levels of microplastic particles present in raw and treated water, wastewater & treated effluent, and the sludges produced by their treatment works.
The secondary objective was to develop a robust sampling and detection methodology to allow the quantification of microplastic particles at a range of different points within the water environment and the water industry’s infrastructure. It should be noted that prior to this project no standardised methods or reference materials were available.
To ensure a representative overview – samples were taken from eight water treatment works (WTW) and eight wastewater treatment works (WwTW) from different companies across Great Britain. For water, the samples included raw water, potable water, and waste sludge from WTWs. For wastewater, samples of influent, effluent and sludge cake were collected from WwTWs. The WTWs’ sites were chosen to represent a range of raw water types, and the WwTWs’ sites were chosen to represent a range of treatment processes. Multiple samples were taken from each site to provide information on the variability of microplastic particles.
By developing cutting-edge analytical methods, the project was able to provide accurate results, and provide a sound foundation on which to develop further research. The project devoted significant effort to understand, quantify and correct for microplastic contamination during sampling and analysis to ensure confidence in the results.
An additional objective was to re-examine a report from 2011 on the likelihood of nanoparticles entering potable water. It was considered that this report had over-estimated market growth and hence risks, but understanding is still hampered by the lack of suitable methods for routine analysis (see full report in Appendix G which is provided as a separate document).