Nanoplastics are emerging environmental contaminants, but their presence in environmental and potable water remains largely understudied due to the absence of quantitative analytical methods. In this study, we developed and validated a pretreatment method that combines hydrogen peroxide digestion and Amicon® Stirred Cell ultrafiltration (at 100 kDa, approximately 10 nm) with subsequent detection by pyrolysis gas chromatography-mass spectrometry (Pyr-GC/MS). This method allows for the simultaneous identification and quantification of nine selected nanoplastic types, including poly(ethylene terephthalate) (PET), polyethylene (PE), polycarbonate (PC), polypropylene (PP), poly(methyl methacrylate) (PMMA), polystyrene (PS), polyvinylchloride (PVC), nylon 6, and nylon 66, in environmental and potable water samples based on polymer-specific mass concentration. Limits of quantification ranged from 0.01 to 0.44 µg/L, demonstrating the method's ability to quantitatively detect nanoplastics in environmental and potable water samples. Most of the selected nanoplastics were detected at concentrations of between 0.04 and 1.17 µg/L, except for PC, which was consistently below the limit of detection (<0.44 µg/L). The prevalent polymer components in the samples were PE (0.10 - 1.17 µg/L), PET (0.06 - 0.91 µg/L), PP (0.04 - 0.79 µg/L), and PS (0.06 - 0.53 µg/L) nanoplastics. The presented analytical method offers an accurate means to identify, quantify, and monitor nanoplastics in complex environmental and potable water samples. It fills gaps in our understanding of nanoplastic pollution levels, providing a valuable methodology and crucial reference data for future studies.

Plastics accumulate in the natural environment due to their durability and low recycling volumes. Wastewater treatments plants (WWTPs) have been identified as important sources for the release of plastics into aquatic and terrestrial environments that may lead to further contamination. This review provides a comprehensive summary of current knowledge on plastic pollution from WWTPs. Specifically, this article presents the current status on the sources of plastics entering WWTPs via influent, the occurrence of plastics in WWTP influent, treated effluent and sewage sludge as well as the techniques used for sampling and analysing plastics in WWTP derived samples. The fate and transfer of plastics from WWTPs to aquatic and terrestrial ecosystems is also discussed. While various studies have reported the presence of plastics in WWTP samples, which have certainly improved our level of understanding on the fate of plastics within the WWTP treatment chain, many unanswered questions still remain. A major gap is the lack of standardized methods and robust analytical techniques for the sampling, identification and quantification of plastics including nano-sized plastics in WWTP derived samples, leading to the potential underestimation of total plastics. To aid comparison of data generated by different researchers, we advocate for the harmonisation of sampling approaches, extraction methods, analytical techniques and reporting units for plastics abundance. Future studies should focus on enhanced methods that can also include estimates of nano-sized plastics.