New Spectroscopy Method Measures Nano/Microplastics in Soil
Researchers have developed a groundbreaking method for measuring nano and microplastic (N/MP) concentrations in soil using a two-wavelength spectroscopy technique. This innovative approach eliminates the need for separating soil organic matter and can accurately detect N/MPs smaller than 1 µm.
The Problem with Current Techniques
Existing methods for measuring N/MP concentrations in soil involve complex chemical and physical separation processes to isolate organic matter, followed by analysis using advanced techniques like microscopy, FTIR spectroscopy, pyrolysis-GC/MS, or Raman spectrometry. These techniques not only require specialized skills but also struggle with detecting N/MPs smaller than 1 µm and often result in the loss of some N/MPs during the separation process, leading to inaccurate measurements.
The New Spectroscopy-Based Method
A team led by Mr. Kyouhei Tsuchida from Waseda University, along with researchers from the National Institute of Advanced Industrial Science and Technology, developed a simpler, more accurate method to measure N/MP concentrations in soil. Their technique utilizes spectroscopy to measure how much light at specific wavelengths is absorbed by the soil sample. This method allows for the detection of N/MPs without the need for separation and can accurately measure N/MPs regardless of size.
The researchers created six soil suspensions with varying characteristics and spiked them with polystyrene nanoparticles to simulate N/MP contamination. By measuring the absorbance of these suspensions at wavelengths ranging from 200 to 500 nm, they identified the optimal wavelength combinations for accurate N/MP measurement. The wavelengths 220-260 nm and 280-340 nm provided the lowest error levels across different soil types.
Results and Implications
The findings, published in the journal Ecotoxicology and Environmental Safety on May 28, 2024, demonstrate the effectiveness of this novel method. The researchers established a linear calibration curve between the N/MP concentrations in soil suspensions and the N/MP content added to dry soil samples. This new method provides a simple, accurate way to measure N/MPs in soil, offering a valuable tool for assessing environmental contamination and understanding the distribution and movement of these pollutants.
Mr. Tsuchida highlighted the potential of this method for quantifying various types of N/MPs, including polyethylene and polyethylene terephthalate, in diverse soil types. This advancement could significantly enhance the initial assessment of N/MP contamination and improve our understanding of their environmental impact.
This novel spectroscopy-based method represents a significant advancement in environmental science, providing a simpler and more accurate way to measure nano and microplastics in soil. By eliminating the need for complex separation processes, this technique offers a practical tool for researchers and environmentalists to better assess and mitigate the impact of N/MP pollution.
For more detailed information, please refer to the original study published in Ecotoxicology and Environmental Safety.
Reference
Title of original paper: A novel and simple method for measuring nano/microplastic concentrations in soil using UV-Vis spectroscopy with optimal wavelength selection
Journal: Ecotoxicology and Environmental Safety
DOI: https://doi.org/10.1016/j.ecoenv.2024.116366
