Extraction and identification of a wide range of microplastic polymers in soil and compost

Franja Prosenc (Author), Pia Leban (Author), Urška Šunta (Author), Mojca Bavcon Kralj (Author)

Abstract

Microplastic pollution is globally widespread; however, the presence of microplastics in soil systems is poorly understood, due to the complexity of soils and a lack of standardised extraction methods. Two commonly used extraction methods were optimised and compared for the extraction of low-density (polyethylene (PE)) and high-density microplastics (polyethylene (PET)), olive-oil-based extraction, and density separation with zinc chloride (ZnCl2). Comparable recoveries in a low-organic-matter matrix (soil; most >98%) were observed, but in a high-organic-matter matrix (compost), density separation yielded higher recoveries (98 ± 4% vs. 80 ± 11%). Density separation was further tested for the extraction of five microplastic polymers spiked at different concentrations. Recoveries were >93% for both soil and compost, with no differences between matrices and individual polymers. Reduction in levels of organic matter in compost was tested before and after extraction, as well as combined. Double oxidation (Fenton’s reagent and 1 M NaOH) exhibited the highest reduction in organic matter. Extracted microplastic polymers were further identified via headspace solid-phase microextraction–gas chromatography–mass spectrometry (HS-SPME–GC–MS). This method has shown the potential for descriptive quantification of microplastic polymers. A linear relationship between the number of particles and the signal response was demonstrated for PET, polystyrene (PS), polyvinyl chloride (PVC), and PE (R$^2$ > 0.98 in alluvial soil, and R$^2$ > 0.80 in compost). The extraction and identification methods were demonstrated on an environmental sample of municipal biowaste compost, with the recovery of 36 ± 9 microplastic particles per 10 g of compost, and the detection of PS and PP.

Keywords

ekstrakcija mikroplastike;pridobivanje olja;ločevanje gostote;GC–MS;masna spektrometrija;plastični polimeri;polietilen tereftalat;polietilen;microplastic extraction;oil extraction;density separation;mass spectrometry;plastic polymers;polyethylene terephthalate;polyethylene;

Data

Language:	English
Year of publishing:	2021
Typology:	1.01 - Original Scientific Article
Organization:	UL ZF - University College of Health Studies
UDC:	543.51:691.175
COBISS:	89126147
ISSN:	2073-4360
Views:	208
Downloads:	84
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	Slovenian
Secondary keywords:	ekstrakcija mikroplastike;pridobivanje olja;ločevanje gostote;GC–MS;masna spektrometrija;plastični polimeri;polietilen tereftalat;polietilen;
Type (COBISS):	Article
Pages:	str. 1-16
Volume:	ǂVol. ǂ13
Issue:	ǂiss. ǂ23
Chronology:	2021
DOI:	10.3390/polym13234069
ID:	14092801