Tracing the Transport and Residence Times of Atmospheric Microplastics Using Natural Radionuclides

Area of Science:

• Environmental Science
• Atmospheric Chemistry
• Radiochemistry

Background:

• Atmospheric microplastics are recognized for long-range transport, but their atmospheric residence times and transport mechanisms remain poorly understood.
• Understanding these factors is crucial for assessing the environmental impact and risks associated with microplastic pollution.

Purpose of the Study:

• To investigate the transport processes and residence times of atmospheric microplastics in Tianjin, a coastal city in Northern China.
• To utilize natural radionuclides as tracers for atmospheric particle transport.

Main Methods:

• Deployment of natural radionuclides (7Be, 210Pb, 210Po) to track atmospheric particles.
• Year-round monitoring of microplastic concentrations and characteristics (size, shape, surface morphology).
• Analysis of atmospheric particle residence times and correlation with radionuclide levels and meteorological data.

Main Results:

• Microplastic concentrations varied seasonally, with higher fragment proportions and larger sizes observed in winter.
• Atmospheric microplastics exhibited rough surfaces, suggesting potential for pollutant adsorption.
• Particle residence times ranged from 9.47 to 22.85 days, averaging 14.41 days, with peaks possibly linked to specific emission sources like coal consumption.

Conclusions:

• Natural radionuclides effectively traced atmospheric microplastic transport and estimated their residence times.
• Prolonged atmospheric presence and surface characteristics indicate microplastics can act as carriers for chemical pollutants.
• The study highlights the complex atmospheric behavior and potential environmental risks of microplastics.