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Recorded November 19, 2020
Microplastics are small plastic particles with size below 5 mm. They are generated from the fragmentation and wear of plastic objects, paints, textiles, tires, etc., They have been observed in freshwater and marine environments all over the world. They have been found in seafood, beer, tap water, sea salt, and human stools. They can adsorb pathogens and pollutants on their surface, and they might affect the growth and development of aquatic fauna. Only in US and Canada, 878 tons or 3.5 quadrillion microfibers per year make it to environment via wastewater treatment plants, equivalent to 89 million plastic bottles; and microparticles from home laundering is thought to be the main route. For that reason, to address todays concerns about microplastics pollution, the understanding of the fate of microfibers generated during home laundering in aquatic environments is critical.In our research we have studied the number and mass of microfibers released from polyester, cotton, and rayon fabrics in both actual home laundering equipment and also with a LaunderOmeter, an accelerated laundering laboratory device. Additionally, biodegradation of these materials was evaluated in simulated aquatic environments, a local wastewater treatment plant (WWTP), lake, and ocean water, and analysis on the microbial communities before and after the experiments were made. In general, all fabric types released microparticles. It is estimated that 700,000 particles are released per wash load. Cellulose based fabrics release more microfibers than did the polyester textile. Fabrics less resistance to abrasion like cotton are more susceptible to microfiber release and a strong correlation was found. However, the cellulosic fibers were found to readily biodegrade, whereas the polyester fibers remained essentially unchanged during the biodegradation experiments. Cellulosic fabrics with finishes also degraded but at a slower pace relative to the untreated cellulose fabric. The cellulosic fibers were highly assimilated by the bacteria in the environment, whereas the polyester microfibers are expected to persist for very long times. Cellulosic materials promoted a microbiome with enriched micro-organisms that can process cellulose whereas the polyester fibers behaved inertly with respect to the microbiome.
About the Speaker
Dr. Marielis Zambrano is a research assistant at the Department of Forest Biomaterials at NC State. She received her B.S. in Chemical Engineering from the University Los Andes in Venezuela. Sustainability has been central to her career and her time at NC State. She completed groundbreaking work on the impact of microfibers on bacterial communities in natural aquatic settings and is currently evaluating the environmental effects of textile finishes on cellulose-based fibers. Dr. Zambrano is passionate about promoting the circular economy for a sustainable future.