Objective:

To improve the identification and characterization of microplastics in biosolids using advanced analytical techniques.

Key Findings:

• Conventional methods miss smaller microplastics due to focus on larger particles.
• O-PTIR provides higher spatial resolution and better spectra for small targets compared to FTIR and Raman.
• The new counting method significantly reduces microscopy workload while maintaining accuracy.

Interpretation:

The study highlights the need for improved methodologies in microplastic analysis within biosolids, addressing regulatory gaps and enhancing monitoring efficiency.

Limitations:

• The study is based on biosolids from Swedish facilities, which may not represent global conditions.
• Further validation needed to confirm the effectiveness of the new methods across different biosolid types.

Conclusion:

This research advances the field of microplastic detection in biosolids, demonstrating the potential of O-PTIR and innovative counting techniques for more efficient analysis.