New insights into the photo-degraded polystyrene microplastic: Effect on the release of volatile organic compounds

Excessive use of plastics leads to the ubiquity of plastic waste in the environment. Weathering can cause changes in the properties of plastics and lead to the release of various chemicals especially the volatile organic compounds (VOCs). Possible photodegradation pathway of polystyrene (PS) microplastics (MPs) was proposed and verified by the detection of VOCs. Headspace solid phase microextraction (HS-SPME) was employed to investigate the release behavior of VOCs from PS MPs exposed to simulated ultraviolet (UV). Results indicated that although the physicochemical properties of the PS MPs showed no significantly change after UV-irradiation, a variety of toxic VOCs, such as benzene, toluene, and phenol were detected from the irradiated MPs. UV irradiation progressively enhanced the release amount of VOCs with total concentration up to 66 mu g g(-1) after 30 d of exposure, about 2.4 times higher than that stored in the darkness (27 mu g g(-1)). Some compounds (e.g., benzene and toluene) showed an upward trend over irradiation time, while others (e.g., styrene and 2-propenylbenzene) reduced over time. Results also found that the size of MPs could affect the release amounts but without consistent pattern for different VOCs detected in the headspace of the vial. In general, current study provided a new insight on the photo-aging process of MPs.

Automated summary

The excessive use of plastics has resulted in the widespread presence of plastic waste in our environment, which leads to the release of toxic chemicals, particularly volatile organic compounds (VOCs). This study investigated the release behavior of VOCs from polystyrene microplastics (MPs) after exposure to simulated ultraviolet (UV) radiation. The results showed that UV irradiation enhanced the release of VOCs, with certain compounds increasing in concentration over time while others decreased. The study provides new insights into the photo-aging process of MPs.