Eye-glass polishing wastewater as significant microplastic source: Microplastic identification and quantification

Area of Science:

• Environmental Science
• Materials Science
• Analytical Chemistry

Background:

• Microplastics (MPs) and nanoplastics (NPs) are pervasive environmental contaminants.
• NPs (<1 µm) evade conventional wastewater treatment due to their small size and high surface area.
• These plastics can adsorb hazardous chemicals, increasing environmental risk.

Purpose of the Study:

• To quantify MPs and NPs generated from eyeglass lens polishing.
• To analyze the composition and characteristics of these plastics.
• To assess the potential environmental and occupational hazards.

Main Methods:

• Fourier-transform infrared (FTIR) and Raman spectroscopy for MP identification.
• Light diffraction for particle size distribution analysis.
• Mass balance with membrane filtration and polyaluminum chloride coagulation for MP quantification.

Main Results:

• Eyeglass lens polishing is a significant source of MPs and NPs in wastewater.
• Wastewater contained substantial amounts of MPs (1380–62,539 mg/L) and NPs (0.0136–0.0324 mg/L).
• MPs were confirmed to adsorb heavy metals, and volatile organic compounds were detected, indicating hazardous conditions.

Conclusions:

• The eyeglass industry contributes significantly to microplastic and nanoplastic pollution.
• Wastewater treatment plants are ineffective at removing NPs from this source.
• Occupational exposure to hazardous chemicals and environmental contamination are serious concerns.