» Articles » PMID: 38280916

Detection and Specific Chemical Identification of Submillimeter Plastic Fragments in Complex Matrices Such As Compost

Overview
Journal Sci Rep
Specialty Science
Date 2024 Jan 27
PMID 38280916
Authors
Affiliations
Soon will be listed here.
Abstract

Research on the plastic contamination of organic fertilizer (compost) has largely concentrated on particles and fragments > 1 mm. Small, submillimeter microplastic particles may be more hazardous to the environment. However, research on their presence in composts has been impeded by the difficulty to univocally identify small plastic particles in such complex matrices. Here a method is proposed for the analysis of particles between 0.01 and 1.0 mm according to number, size, and polymer type in compost. As a first demonstration of its potential, the method is used to determine large and small microplastic in composts from eight municipal compost producing plants: three simple biowaste composters, four plants processing greenery and cuttings and one two-stage biowaste digester-composter. While polyethylene, PE, tends to dominate among fragments > 1 mm, the microplastic fraction contained more polypropylene, PP. Whereas the contamination with PE/PP microplastic was similar over the investigated composts, only composts prepared from biowaste contained microplastic with a signature of biodegradable plastic, namely poly(butylene adipate co-terephthalate), PBAT. Moreover, in these composts PBAT microplastic tended to form the largest fraction. When the bulk of residual PBAT in the composts was analyzed by chloroform extraction, an inverse correlation between the number of particles > 0.01 mm and the total extracted amount was seen, arguing for breakdown into smaller particles, but not necessarily a mass reduction. PBAT oligomers and monomers as possible substrates for subsequent biodegradation were not found. Remaining microplastic will enter the environment with the composts, where its subsequent degradability depends on the local conditions and is to date largely uninvestigated.

References
1.
Blasing M, Amelung W . Plastics in soil: Analytical methods and possible sources. Sci Total Environ. 2017; 612:422-435. DOI: 10.1016/j.scitotenv.2017.08.086. View

2.
Steiner T, Zhang Y, Moller J, Agarwal S, Loder M, Greiner A . Municipal biowaste treatment plants contribute to the contamination of the environment with residues of biodegradable plastics with putative higher persistence potential. Sci Rep. 2022; 12(1):9021. PMC: 9151778. DOI: 10.1038/s41598-022-12912-z. View

3.
Kim S, Waldman W, Kim T, Rillig M . Effects of Different Microplastics on Nematodes in the Soil Environment: Tracking the Extractable Additives Using an Ecotoxicological Approach. Environ Sci Technol. 2020; 54(21):13868-13878. PMC: 7643727. DOI: 10.1021/acs.est.0c04641. View

4.
Napper I, Thompson R . Environmental Deterioration of Biodegradable, Oxo-biodegradable, Compostable, and Conventional Plastic Carrier Bags in the Sea, Soil, and Open-Air Over a 3-Year Period. Environ Sci Technol. 2019; 53(9):4775-4783. DOI: 10.1021/acs.est.8b06984. View

5.
Gui J, Sun Y, Wang J, Chen X, Zhang S, Wu D . Microplastics in composting of rural domestic waste: abundance, characteristics, and release from the surface of macroplastics. Environ Pollut. 2021; 274:116553. DOI: 10.1016/j.envpol.2021.116553. View