Unmasking per- and polyfluoroalkyl substances (PFAS) in facemasks: Occurrence and leaching implications

Area of Science:

• Environmental Chemistry
• Contaminant Analysis
• Materials Science

Background:

• The COVID-19 pandemic led to widespread facemask use and disposal.
• This generates potential risks for human exposure and environmental release of emerging contaminants like per- and polyfluoroalkyl substances (PFAS).
• Previous research has not fully addressed PFAS leaching behavior from diverse facemask types, especially those from the Chinese market.

Purpose of the Study:

• To quantify per- and polyfluoroalkyl substances (PFAS) in prominent facemask types.
• To estimate unidentified PFAS precursors using the total oxidizable precursor (TOP) assay.
• To evaluate PFAS leaching under disposal-relevant conditions, considering temperature and dissolved organic matter.

Main Methods:

• Quantification of 21 PFAS (∑₂₁PFAS) in facemask solids.
• Analysis of PFAS release into water under simulated disposal conditions.
• Application of the total oxidizable precursor (TOP) assay to identify and quantify precursors.
• Investigation of leachate conditions (temperature, dissolved organic matter) impacting PFAS leachability.

Main Results:

• Facemasks contained relatively low ∑₂₁PFAS concentrations (0.68-5.3 ng/g) with 0.49-2.3 ng/g released to water.
• A reusable cloth facemask showed substantial unidentified precursors via the TOP assay.
• PFAS leaching was thermodynamically non-spontaneous, with leachability ranging from 14.8% to 84.7%.
• Leachate temperature increase (10°C) raised leaching by ~14%, while dissolved organic matter increased it by 102-300%.
• Annual disposal of 250-480 billion facemasks is estimated to release 0.72-1.4 kg of ∑₂₁PFAS and 0.50-0.98 kg of ∑₇PFCAs into leachates.

Conclusions:

• Facemasks contribute to environmental PFAS loading, particularly under specific leachate conditions.
• The presence of unidentified precursors in some masks warrants further investigation.
• Understanding leaching factors is crucial for assessing the environmental impact of facemask waste.