Identification of microplastics in landfill leachate: An underestimated tiny microplastics using Focal Plane Array...

Area of Science:

• Environmental Science
• Analytical Chemistry
• Materials Science

Background:

• Landfills are a major source of environmental microplastics (MPs).
• Accurate identification and quantification of tiny MPs (10-100 µm) in landfill leachate is a significant challenge.
• Understanding MP behavior in leachate is crucial for assessing environmental transport.

Purpose of the Study:

• To comparatively investigate the identification and quantification of MPs in leachate from operating and closed landfills.
• To evaluate the efficiency of ATR-FTIR and FPA-FTIR imaging techniques for detecting tiny MPs.
• To determine the abundance, morphology, and influencing factors of MPs in landfill leachate across China.

Main Methods:

• Comparative analysis of attenuated total reflectance-Fourier transform infrared (ATR-FTIR) and focal plane array-based micro-Fourier transform infrared (FPA-FTIR) imaging.
• Determination of MPs in leachate from 13 landfills in China using FPA-FTIR.
• Analysis of MP abundance, morphology, and correlation with landfill age and operational conditions.

Main Results:

• FPA-FTIR detected MPs at concentrations two orders of magnitude higher than ATR-FTIR, demonstrating superior efficiency for tiny MPs.
• MPs in leachate primarily consisted of white fragments of high-density engineering plastics (90%).
• MP abundance varied significantly with landfill age and operational status, peaking around 15 years in operating landfills and decreasing with closure age in closed landfills.

Conclusions:

• FPA-FTIR imaging is a more effective method for quantifying tiny MPs in landfill leachate.
• Landfill operational conditions and age significantly influence MP quantity but not morphology.
• This research provides critical data for understanding MP migration from landfills into leachate.