Assessment of microplastic digestion methods in source and treated drinking waters

Area of Science:

• Environmental Science
• Analytical Chemistry
• Water Quality

Background:

• Microplastic analysis in drinking water necessitates effective isolation techniques.
• Existing methods for isolating microplastics often lack systematic evaluation for drinking water matrices.
• Non-plastic interferences hinder accurate microplastic quantification and characterization.

Purpose of the Study:

• To systematically evaluate and compare seven different methods for isolating microplastics (>2 μm) from source and treated drinking waters.
• To identify an optimal method for reducing non-plastic organic and inorganic particles.
• To develop and refine a digestion method for reproducible microplastic analysis.

Main Methods:

• Direct comparison of seven established oxidation, digestion, and acidification methods.
• Evaluation of Fenton's reagent oxidation combined with cellulase and trypsin enzymatic digestion.
• Optimization of the digestion method through acidification timing and reduced reaction times.
• Validation of the improved method on diverse surface water samples.

Main Results:

• Fenton's reagent oxidation followed by enzymatic digestion significantly improved clean filter area and reduced particle counts.
• Method optimization minimized iron precipitate formation and reduced sample processing time.
• The refined method demonstrated applicability and reproducibility across different surface water types.

Conclusions:

• The optimized Fenton's reagent oxidation and enzymatic digestion method is highly effective for microplastic isolation from drinking water.
• This improved method offers a standardized approach for pre-analysis of microplastics in various water sources.
• The findings facilitate more accurate microplastic characterization using spectroscopic techniques.