Quantification of polyethylene terephthalate micro- and nanoplastics in domestic wastewater using a simple three-step method

Concerns about impact of small plastic particles, known as microplastics (<5 mm) and nanoplastics (<1 μm), together abbreviated as MNP, on the environment and on human health have increased in recent years. Polyethylene terephthalate (PET) microplastics have been detected previously in different environmental samples including freshwater and wastewater sludge. In the present study, we target all small plastic particles of PET with a diameter smaller than 5 mm (‘PET MNP’). A simple three-step method of drying, (in matrix) PET depolymerization in ethylene glycol and liquid chromatography-mass spectrometry (LC-MS) analysis, was applied for the quantification of PET MNP in influents and effluents collected from ten Dutch wastewater treatment plants. The PET recovery was 98 % in the wastewater matrix. The limits of detection (LOD) for PET in influents and effluents were 2.0 μg/L and 1.2 μg/L, respectively. PET MNP was detected in all the influents (ranging from 24.9 μg/L to 680 μg/L) and most of the effluents (ranging from <LOD to 23.1 μg/L). The results of the present study confirmed that WWTP effluents can be a source of PET MNP in the environment.