UV aging may enhance adsorption capacity of Poly (butylene adipate-co-terephthalate) (PBAT) to heavy metals and toxicity to zebrafish.

Compared with the fossil-based plastics, biodegradable plastics are more easily decomposed into small-sized particles (e.g., microplastics). However, the role of aged biodegradable plastics in being vector of co-existed pollutants and potential toxicological effects remain to be elucidated. The present study selected micro-sized biodegradable polymer Poly (butylene adipate-co-terephthalate) (PBAT) as the object, aiming to explore its aging process, environmental behavior with heavy metals (Cu and Pb), and the toxic effects on zebrafish. The results showed that distinct changes such as cracks and severe deformation can be observed on the surface of PBAT after 60 days of UV aging, and the functional groups changed consequently. The maximum adsorption capacity of aged PBAT for Cu and Pb reached 0.967 and 0.939 mg·g-1, which increased by 1.32 and 1.46 times, respectively. The results of 7-day acute toxicology experiments suggested that the adsorption behavior of aged PBAT may alleviate the toxic effects of heavy metals Cu and Pb on zebrafish in short-term exposure, however it could simultaneously cause a serious imbalance of intestinal microorganisms in zebrafish. As demonstrated, the coexistence of aged PBAT and heavy metals (Cu, Pb) can seriously reduce the intestinal microbial diversity and richness of zebrafish, which may induce more serious toxicity and disease in long-term exposure to pollutants. This study could provide fundamental data for better understanding on the adsorption behavior and ecological risk of aged biodegradable plastics with coexisted pollutants.

Research of the Changes in the Psychological Status of Chinese University Students and the Influencing Factors During the COVID-19 Pandemic.

Background: Psychological dynamics of college students have changed during the COVID-19 outbreak but little research has been done in this area. The purpose of this study is to investigate the dynamic changes in the mental health status of college students since the outbreak of the COVID-19 pandemic 1 year and the influencing factors. Methods: The research period was from February 2020 to August 2021. 384 college students were analyzed three times during this period on the recognition and psychological state of the pandemic. Results: During the period from February 2020 to August 2021, in general, the positive scores rose from 20.79 to 23.46, while the negative scores dropped from 17.41 to 14.00. The regression analysis results on the influencing factors showed the degree of recognition of the pandemic is all significant in the three phases (p < 0.05). Conclusion: With the effective control of the pandemic, the mental state of the students showed a slight improvement in the environment of sporadic cases. Behavior has a partial mediating effect between the source of fear and psychological changes. Correct behavior guidance can effectively reduce the psychological changes caused by college students' fear.

Metabolomics-based non-targeted screening analysis of 34 PPCPs in bovine and piscine muscles.

The metabolomics-based analytical strategy has showed superiority on the non-targeted screening of contaminants, especially for unknown and unexpected (U&U) contaminants in the field of food safety, but data analysis is often the bottleneck of the strategy. In this study, a novel metabolomics-based analytical method via searching for marker compounds was developed on the basis of ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) results to accurately, rapidly and comprehensively achieve the non-targeted screening of 34 pharmaceutical and personal care products (PPCPs) as U&U contaminants spiked in bovine and piscine muscle matrices. Three concentration groups (20, 50 and 100 ng mL-1) were intentionally designed to simulate the control and experimental groups for the discovery of marker compounds, for which multivariate and univariate analyses were adopted. In multivariate analysis, each concentration group was fully separated from the other two groups in PCA and OPLS-DA plots, laying a foundation to distinguish marker compounds among groups. The S-plot, permutation and variable importance in projection (VIP) in OPLS-DA were employed to screen and identify marker compounds, which were further verified by pairwise t-test and fold change judgement in univariate analysis. The results indicate that 34 PPCPs spiked in two muscle matrices were all identified as marker compounds, proving the validity and practicability of this novel metabolomics-based non-targeted screening method, which will exhibit great superiority and broad application prospects, especially in the face of massive PPCPs and various animal matrices in the field of food safety control. In addition, the limits of detection (LODs) for 34 PPCPs were calculated to be 0.2-2.6 µg kg-1 and 0.3-2.1 µg kg-1 in bovine and piscine muscle matrices, respectively.