PNNL

Abstract

Micro- and nanoplastic (MNP) particles are of increasing environmental concern related to the widespread uncontrolled degradation of various commercial products made of plastic and their associated waste disposal. Recently, common technology used to repair sewer pipes was reported as one of the emission sources of airborne MNP in urban areas. This research presents results of the multi-modal comprehensive chemical characterization of the MNP particles related to waste discharged in the pipe repair process and compares MNP composition with the components of uncured resin and cured plastic composite used in the process. Analysis of these materials employs complementary use of surface-enhanced Raman spectroscopy, scanning transmission xray spectro-microscopy, single particle mass spectrometry, and direct analysis in realtime high-resolution mass spectrometry. It is shown that the composition of the relatively large MP particles resembles components of plastic material used in the process. In contrast, the composition of the NP particles is significantly different, suggesting their formation from unintended polymerization of water-soluble components occurring in drying droplets of the air-discharged waste. In addition, resin material type influences the composition of released MNP particles. Results are further discussed to guide the detection and advanced characterization of NP particles in future field studies.