Tracing source of microplastics contamination in CTC tea: Effect of processing stages and human health risk assessment

Globally, tea is a widely consumed beverage and is reported to be contaminated with microplastics (MPs), especially in tea bags. However, data is lacking in CTC (‘crush, tear, curl’) tea with a possible source appointment. Present study investigated abundance of MPs at different stages of CTC tea manufacturing process. MPs (10–82.4 μm) contamination was found highest at fermentation stage (1.1 particles g⁻¹) and lowest at drying stage (0.4 particles g⁻¹), with prevalence of polyethylene, polyacrylates, polyvinyl chloride, and nylon. Plucking, cutting & rolling stages were associated with a higher abundance of fibrous and fragmented MPs. Further, tea processing equipment made of plastics, viz., withering trough, conveyor belt, fiber extractor machine, etc., contributes to MPs contamination in CTC tea. EDI_particles for CTC tea and brewed tea were 0.03–0.2 and 0.05–0.28 particles kg BW⁻¹ day⁻¹, respectively. Estimated average rate of MPs ingested (ARMI) was 6.19–73.9 μg person⁻¹ year⁻¹. Non-cancer (HQ) and cancer risk (ILCR) indices ranged from 1.53 × 10⁻⁸ to 5.44 × 10⁻⁵ and 1.45 × 10⁻⁹ to 2.59 × 10⁻⁷, respectively, which are within safety limits. The study generates baseline data for MPs contamination in processing stages of CTC tea and health risk associated with it.