Sampling and extraction methods for soil microplastics: current advances and limitations
- 1Corresponding author.
- 2Faculty of Water Supply and Environmental Engineering, Arba Minch Water Technology Institute, Arba Minch University, Arba Minch, Ethiopia
Abstract
Soil contamination with microplastic (MP) poses significant methodological issues since soil variability, particle properties, and analytical techniques can all have a large effect on reported concentrations. This review critically evaluates soil-MP sampling, preparation, extraction, separation, and identification methods based on recovery efficiency, reproducibility and validation, matrix dependence, polymer selectivity, particle-size capability, detection limits, analytical uncertainty, processing requirements, and compatibility with polymer identification. A thorough literature search conducted in February 2025 yielded 97 relevant studies. According to the reviewed data, sample performance is determined by regional variability, sampling depth and mass, replication, and research aims, with no single design being uniformly representative. Aggregate dispersion and organic matter removal have a significant impact on recovery, especially in fine-textured and organically rich soils. Density separation performance is determined by both effective matrix liberation and flotation-medium density. Saturated NaCl is typically suitable for low-density polymers like PE and PP, but it may under-recover higher-density polymers like PVC, PET, and PA. ZnCl₂- and NaI-based media can improve polymer recovery, but they have higher viscosity, toxicity, reagent recycling, and waste disposal needs. Electrostatic, oil-based, pressurized-fluid, and magnetic approaches all have complementing capabilities, but they differ in recovery performance, matrix dependency, equipment needs, scalability, and analytical compatibility. Polymer confirmation using FTIR, micro-FTIR, Raman spectroscopy, or thermal analysis entails further trade-offs in particle size capabilities and detection limitations. Overall, technique selection should be influenced by analytical performance and research objectives rather than only reagent cost. Recovery studies, procedural blanks, contamination controls, replication, and clear reporting of detection limits and reporting units are critical for increasing the reliability and comparability of soil-MP results.
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BibTeX
@article{kasa2026sampling,
title = {{Sampling and extraction methods for soil microplastics: current advances and limitations}},
author = {Tilahun Kasa and Daniel Reddythota and Melsew Endalew Berihun and Sintayehu Yadete Tola and Yohannis Kifle Beyene},
journal = {Environmental Challenges},
year = {2026},
month = oct,
doi = {10.1016/j.envc.2026.101696},
url = {https://doi.org/10.1016/j.envc.2026.101696},
note = {CC BY},
}
RIS
TY - JOUR
TI - Sampling and extraction methods for soil microplastics: current advances and limitations
AU - Tilahun Kasa
AU - Daniel Reddythota
AU - Melsew Endalew Berihun
AU - Sintayehu Yadete Tola
AU - Yohannis Kifle Beyene
PY - 2026
DA - 2026/10/31
JO - Environmental Challenges
DO - 10.1016/j.envc.2026.101696
UR - https://doi.org/10.1016/j.envc.2026.101696
AB - Soil contamination with microplastic (MP) poses significant methodological issues since soil variability, particle properties, and analytical techniques can all have a large effect on reported concentrations. This review critically evaluates soil-MP sampling, preparation, extraction, separation, and identification methods based on recovery efficiency, reproducibility and validation, matrix dependence, polymer selectivity, particle-size capability, detection limits, analytical uncertainty, processing requirements, and compatibility with polymer identification. A thorough literature search conducted in February 2025 yielded 97 relevant studies. According to the reviewed data, sample performance is determined by regional variability, sampling depth and mass, replication, and research aims, with no single design being uniformly representative. Aggregate dispersion and organic matter removal have a significant impact on recovery, especially in fine-textured and organically rich soils. Density separation performance is determined by both effective matrix liberation and flotation-medium density. Saturated NaCl is typically suitable for low-density polymers like PE and PP, but it may under-recover higher-density polymers like PVC, PET, and PA. ZnCl₂- and NaI-based media can improve polymer recovery, but they have higher viscosity, toxicity, reagent recycling, and waste disposal needs. Electrostatic, oil-based, pressurized-fluid, and magnetic approaches all have complementing capabilities, but they differ in recovery performance, matrix dependency, equipment needs, scalability, and analytical compatibility. Polymer confirmation using FTIR, micro-FTIR, Raman spectroscopy, or thermal analysis entails further trade-offs in particle size capabilities and detection limitations. Overall, technique selection should be influenced by analytical performance and research objectives rather than only reagent cost. Recovery studies, procedural blanks, contamination controls, replication, and clear reporting of detection limits and reporting units are critical for increasing the reliability and comparability of soil-MP results.
SN - 2667-0100
ER -