Pre-Washing Reduce the Microplastics in Tea Infusions Released from Filter Bags: Quantitative Evidences Based on Raman Imaging and Py-Gc/Ms

Abstract

The convenience of bagged tea is favored by consumers, however, microplastics released from plastic-based filter bags in tea infusions have attracted widespread attention. Micron- and submicron-sized microplastics in tea infusions were identified and quantified using Raman imaging and Py-GC/MS, respectively. The results showed that tea bags released microplastics into tea infusions, with about 80 to 1288 pieces (micron-sized) and 0 to 63.755 μg (submicron-sized) per filter bag. In comparison, microplastics released from nylon 6 woven tea bags were much lower than those from nonwoven filter bags. Fortunately, three pre-washes with room temperature water significantly reduced microplastic residues, with removal rates of 76–94% (micron-sized) and 80–87% (submicron-sized), respectively. It is recommended that manufacturers wash the filter bags before dispensing tea, and consumers can also pre-wash the bags several times before soaking the tea to reduce the risk of human exposure to microplastics during tea consumption.

Keywords: Tea infusion, Microplastics, Raman imaging, Py-GC/MS, Plastic-based filter bag, Quantitative estimation