Extraction and characterization of microplastics in soil: A case study from the Hetao Irrigation District

Microplastics (MPs) pollution has become a global environmental issue. Soil, as a key environmental medium, serves as an important sink and carrier of MPs. Accurate and efficient extraction of MPs from soil matrices is essential for understanding their distribution, composition, and environmental be...

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Main Authors: Ho, Chia Min, Feng, Weiying, Deng, Yuxin, Li, Xiaofeng, Ngien, Su Kong
Format: Article
Language:English
Published: MDPI 2025
Subjects:
Online Access:https://umpir.ump.edu.my/id/eprint/45641/
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author Ho, Chia Min
Feng, Weiying
Deng, Yuxin
Li, Xiaofeng
Ngien, Su Kong
author_facet Ho, Chia Min
Feng, Weiying
Deng, Yuxin
Li, Xiaofeng
Ngien, Su Kong
author_sort Ho, Chia Min
building UMP Institutional Repository
collection Online Access
description Microplastics (MPs) pollution has become a global environmental issue. Soil, as a key environmental medium, serves as an important sink and carrier of MPs. Accurate and efficient extraction of MPs from soil matrices is essential for understanding their distribution, composition, and environmental behavior. This study presents a refined extraction method that combines two-step density separation with sodium chloride (NaCl, 1.20 g/cm3), hydrogen peroxide (H2O2) digestion for organic matter removal and a Fractionated Filtration Method (FFM) to capture MPs across multiple particle size ranges. Polymer identification and size characterization were performed using the high-throughput Agilent 8700 Laser Direct Infrared (LDIR) imaging system. Method validation demonstrated a recovery rate of 85% based on 100 μm MPs standards spiked into soil and minimal background contamination of 5–8 particles in blank controls, confirming the reliability of the workflow. Applying this method to agricultural soils from the Hetao Irrigation District revealed widespread MP contamination, with concentrations ranging from 5778 to 31,489 particles/kg and an average of 16,461 ± 8097 particles/kg. More than 99% of MPs were smaller than 500 μm, with the 10–30 μm fraction dominating the distribution. Polypropylene (PP), polyamide (PA), and polyethylene (PE) accounted for over 90% of detected MPs. This refined method enables reproducible extraction and accurate characterization of fine MPs in complex soil environments and provides a practical foundation for advancing standardized soil MP monitoring protocols.
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spelling ump-456412025-09-19T07:38:33Z https://umpir.ump.edu.my/id/eprint/45641/ Extraction and characterization of microplastics in soil: A case study from the Hetao Irrigation District Ho, Chia Min Feng, Weiying Deng, Yuxin Li, Xiaofeng Ngien, Su Kong TA Engineering (General). Civil engineering (General) TD Environmental technology. Sanitary engineering Microplastics (MPs) pollution has become a global environmental issue. Soil, as a key environmental medium, serves as an important sink and carrier of MPs. Accurate and efficient extraction of MPs from soil matrices is essential for understanding their distribution, composition, and environmental behavior. This study presents a refined extraction method that combines two-step density separation with sodium chloride (NaCl, 1.20 g/cm3), hydrogen peroxide (H2O2) digestion for organic matter removal and a Fractionated Filtration Method (FFM) to capture MPs across multiple particle size ranges. Polymer identification and size characterization were performed using the high-throughput Agilent 8700 Laser Direct Infrared (LDIR) imaging system. Method validation demonstrated a recovery rate of 85% based on 100 μm MPs standards spiked into soil and minimal background contamination of 5–8 particles in blank controls, confirming the reliability of the workflow. Applying this method to agricultural soils from the Hetao Irrigation District revealed widespread MP contamination, with concentrations ranging from 5778 to 31,489 particles/kg and an average of 16,461 ± 8097 particles/kg. More than 99% of MPs were smaller than 500 μm, with the 10–30 μm fraction dominating the distribution. Polypropylene (PP), polyamide (PA), and polyethylene (PE) accounted for over 90% of detected MPs. This refined method enables reproducible extraction and accurate characterization of fine MPs in complex soil environments and provides a practical foundation for advancing standardized soil MP monitoring protocols. MDPI 2025-09-12 Article PeerReviewed pdf en cc_by_4 https://umpir.ump.edu.my/id/eprint/45641/1/water-17-02700-v2.pdf Ho, Chia Min and Feng, Weiying and Deng, Yuxin and Li, Xiaofeng and Ngien, Su Kong (2025) Extraction and characterization of microplastics in soil: A case study from the Hetao Irrigation District. Water, 17 (18). pp. 1-15. ISSN 2073-4441. (Published) https://doi.org/10.3390/w17182700 https://doi.org/10.3390/w17182700 https://doi.org/10.3390/w17182700
spellingShingle TA Engineering (General). Civil engineering (General)
TD Environmental technology. Sanitary engineering
Ho, Chia Min
Feng, Weiying
Deng, Yuxin
Li, Xiaofeng
Ngien, Su Kong
Extraction and characterization of microplastics in soil: A case study from the Hetao Irrigation District
title Extraction and characterization of microplastics in soil: A case study from the Hetao Irrigation District
title_full Extraction and characterization of microplastics in soil: A case study from the Hetao Irrigation District
title_fullStr Extraction and characterization of microplastics in soil: A case study from the Hetao Irrigation District
title_full_unstemmed Extraction and characterization of microplastics in soil: A case study from the Hetao Irrigation District
title_short Extraction and characterization of microplastics in soil: A case study from the Hetao Irrigation District
title_sort extraction and characterization of microplastics in soil: a case study from the hetao irrigation district
topic TA Engineering (General). Civil engineering (General)
TD Environmental technology. Sanitary engineering
url https://umpir.ump.edu.my/id/eprint/45641/
https://umpir.ump.edu.my/id/eprint/45641/
https://umpir.ump.edu.my/id/eprint/45641/