Microplastics in polystyrene-made food containers from China: abundance, shape, size, and human intake

Polystyrene-made food containers (PMFCs) have been widely used as takeout containers in China. However, the pollution of microplastics (MPs) in PMFCs used in Chinese restaurants remains not well known. For the first time, this study analyzed MPs in PMFC samples (n = 354) collected from different restaurants in 28 Chinese cities. MPs were detected in all PMFC samples, with an abundance of 5-173 items/container. PMFC samples from Taiyuan (mean of 86 items/container) contained the highest mean abundance of MPs. A relatively lower abundance of MPs was found in PMFCs from Urumqi (mean of 19 items/container) and Fuzhou (18 items/container). Fiber was the predominant shape of MPs in most of the PMFC samples. The abundance of MPs in PMFCs was positively correlated with the proportion of fiber. The major polymer composition of MPs was polystyrene, accounting for a mean of 45-90% of total polymers for MPs in PMFCs from different cities. The abundance of MPs in PMFC samples was negatively correlated with the proportion of polystyrene. The mean estimated oral exposure of MPs for the general population in different Chinese cities was 0.24-1.4 items/kg bw/day. Such data is important for human MP exposure risk assessment and also for elucidating the sources of human exposure to MPs.