Landfill liners as a source of microplastics: Do the guards guard themselves?

Area of Science:

• Environmental Science
• Materials Science
• Polymer Science

Background:

• Microplastic contamination is a growing environmental concern, with landfills being a significant source of microplastic release via leachate.
• The contribution of synthetic liners, such as High-Density Polyethylene (HDPE) geomembranes, to microplastic pollution in landfills is not well understood.

Purpose of the Study:

• To investigate the extent to which HDPE geomembrane liners contribute to microplastic concentration in landfill leachate.
• To assess the impact of accelerated aging and temperature on microplastic generation from HDPE liners.

Main Methods:

• 1.5 mm thick HDPE geomembranes were aged in synthetic leachate for four months at 23°C and 50°C.
• Physical, mechanical, and chemical properties were tested monthly to monitor aging.
• Surface morphology was examined using electron microscopy.
• Leachate was analyzed monthly for microplastics using stereomicroscopy and spectral analysis.

Main Results:

• HDPE geomembrane liners released between 475 and 1689 microplastic particles per square meter.
• Microplastic generation was significantly higher at 50°C compared to 23°C.
• The majority of generated microplastic particles were smaller than 20 μm.

Conclusions:

• HDPE geomembrane liners are a notable source of microplastic pollution in landfill leachate.
• Elevated temperatures exacerbate microplastic release from these liners.
• Development of alternative landfill liner materials with reduced environmental impact is crucial.