微纳米塑料在典型日用塑料制品使用过程中的释放规律及机制

Due to their low cost and high convenience, plastic products have become an indispensable part of our daily life, and are widely used in different fields, such as food packaging, clothing, medical, and household products. During consumption in daily life, the physical and chemical properties of plastic products inevitably change under external usage conditions, with the production and release of micro- and nano-plastics (MNPs). These MNPs have a high potential to enter human bodies and pose potential health risks. Therefore, it is of great importance to investigate the release patterns of MNPs from plastic products during their usage in daily life. Recent studies have confirmed the release of MNPs from plastic lunch boxes, disposable paper cups, feeding bottles, and other plastic products during everyday usage. However, the types, abundance, and release mechanisms of MNPs from plastic products are different, which need a comprehensive summary. In this review, the release patterns and related mechanism of MNPs from five types of plastic products including “food packaging and containers”, “maternal and infant products”, “medical and protective equipment”, “clothing and fabrics”, and “other daily necessities” were summarized and analyzed in their respective major use scenarios. Notably, the studies on the “food packaging and containers” plastic products have confirmed that the main type, shape, and size of the released MNPs are polypropylene, particle, and in the size range of 0−100 μm, respectively. More importantly, the abundances of the released nanoplastics are 2−3 times higher than microplastics during the usage processes of plastic products. The release mechanisms of MNPs from plastic products under mechanical crushing, thermal degradation, and other effects (e.g., photo-degradation and microbial degradation) were further summarized, in which mechanical crushing induced by mechanical stresses (e.g., abrasion, agitation, and washing) and the thermal degradation induced by heating or freezing played the most important role in the release of MNPs from plastic products. Additionally, a large number of MNPs will form and adhere to the surface of the plastic products during the manufacturing process, which may be more easily released from the plastic products with the addition of mechanical stress during use. In addition, the key factors affecting the release of MNPs from plastics were discussed. The release of MNPs could be promoted with the increase of mechanical stress, the increase or decrease of temperature, the extension of illumination (ultraviolet light), the increase of the microwave time and intensity, and the exposure of substances (e.g., foods). Types and structural characteristics of plastics are also important factors affecting the release of MNPs. Notably, the effect of microwave radiation on the release of MNPs from plastic products is much higher than that of temperature change or mechanical stress. Meanwhile, the release of additives including organic compounds (e.g., phenols, esters, and other aromatic compounds), heavy metal ions (e.g., arsenic, chromium, and lead ions), and metal nanoparticles (e.g., nano-copper oxide) during the generation of MNPs was discussed. Finally, future perspectives on the investigation of the unrevealed release mechanism of MNPs, the detection of nanoplastics, and the strategies to reduce the release of MNPs in daily-use plastic products are proposed. In addition, research on the release of MNPs from degradable plastic products, as well as the toxicity and potential health risks of MNPs on humans, is also suggested. This review will give comprehensive suggestions and prospects for future research directions on plastic production, and provide forceful scientific support for a better understanding of the human health risks of plastic products.