Keynote Presentation: Using 14C-labelling to study the Degradation of Polystyrene
Rong Ji1, Lili Tian1, Yini Ma1, Philippe Corvini1,2
1 Nanjing University, School of the Environment, Xianlin Avenue 163, Nanjing 210023, China
2 School of Life Sciences, University of Applied Sciences and Arts Northwestern Switzerland, Hofackerstrasse 30, Muttenz CH-4132, Switzerland
Biography
Professor Rong Ji
School of Environmental Science, Nanjing University, China
Dr. Rong Ji is a Professor of Environmental Science at Nanjing University and Associate Director of the National Engineering Research Centre for Organic Pollution Control and Resource Reuse. He received his Ph.D. in Microbial Ecology (Konstanz, Germany, 2000) and conducted postdoctoral research at RWTH Aachen University and Max-Planck Institute for Terrestrial Microbiology (Germany, 2000–2006). His research focus on environmental processes and effects of emerging pollutants (e.g., microplastics, antibiotics) and remediation of contaminated environments. Currently, he is using radioactive and stable isotope-labeled compounds to study the environmental behaviors of microplastics, including bioaccumulation and toxicity, fate in the environment and organisms, and interactions with small organic pollutants. He has led 20+ projects granted by national funds (e.g., NSFC, MOST) and international funds (e.g., European Horizon2020, Swiss SNF), and has published 230+ peer-reviewed papers in international journals (including Nature Nanotechnology, Nature Geoscience, Nature Communications, Environmental Science & Technology).
Abstract
We hypothesized that ageing oxidizes the surface of microplastics and initiates mineralization of microplastics, and that smaller particles (nanoplastics) are more readily mineralized. We synthesized micrometer- and nanometer-sized polystyrene particles with 14C-labelling and quantified their degradation/mineralization by fungi and UV light. PS with lower-molecular-weight were more susceptible to fungal mineralization after surface oxidation by O3, though fungi only targeted oxidized moieties of PS. PS in water was more readily mineralized by UV than in air and produced water-soluble products that microbes easily mineralized. Our findings show that aged PS surface are not inert: environment ageing enhances carbon loss of plastics via microbial and photo-mineralization, which should be considered for plastic carbon balance assessments.