The interaction of micro/nano plastics and the environment: Effects of ecological corona on the toxicity to aquatic organisms.

Concerns about the micro/nano plastics (MNPs) exposure risks have risen in recent years. The ecological corona (EC), which is generated by the interaction between MNPs and environmental substances, has a significant impact on their environmental fate and ecological risks. As the largest sink of MNPs, the aquatic environment is of great significance for understanding the environmental behaviour of MNPs. Transmission Electron Microscope (TME), Fourier Transform Infra-Red (FTIR), Scanning Electron Microscope (SEM), Dynamic Light Scattering (DLS) and other analytical methods have been used as effective methods to analyse the formation process of EC and detect the existing EC directly or indirectly on the surface of MNPs. The physicochemical properties of MNPs, complex aquatic environments and ageing time have been identified as the key factors affecting EC formation in aquatic environments. Moreover, the EC absorbed on MNPs significantly changed their environmental behaviour and toxicity to aquatic organisms. This review gives a full understanding of the EC formation progress on the surface of MNPs and different analytical methods for EC have been summarised which can further assist the ecological risk assessment of MNPs in the aquatic environment.

Correlation of Complex Impacted Mandibular Teeth with Pericoronitis and Effect of Minimally Invasive Tooth Extraction on Patients' Long-term Outcome of Masticatory Ability.

Objective: To explore the correlation of complex impacted mandibular teeth and pericoronitis, as well as the effect of minimally invasive tooth extraction on patients' long-term outcomes of masticatory ability. Methods: A total of 101 patients with complex impacted teeth who were treated in our hospital from March 2019 to June 2021 were selected and divided into the control group (n = 55) and the observation group (n = 46) according to the different treatment methods. The patients in the control group were given conventional extraction treatment, and the patients in the observation group were given minimally invasive extraction treatment. The clinicopathological features of patients complicated by pericoronitis were observed and the relationship between complex impacted mandibular teeth and pericoronitis was discussed. Additionally, we made statistics on operative time (OT), intraoperative blood loss (IBL), dental socket integrity score, and adverse reactions (ARs) and compared the clinical efficacy between the observation group and control group. The Visual Analogue Scale (VAS) and Oral Health Impact Profile scale (OHIP-14) were utilized for pain assessment and oral health status evaluation, respectively. Bite force (BF) and masticatory efficiency were also measured. Results: OG showed less OT and IBL than CG, with a higher dental socket integrity score (P < 0.05). In addition, OG outperformed CG with a higher overall response rate and a lower incidence of ARs (P < 0.05). The pretreatment VAS score, mouth-opening degree, and OHIP-14 score differed insignificantly between groups (P > 0.05). After treatment, the VAS score of OG decreased, while the mouth-opening degree and OHIP-14 score increased (P < 0.05). Finally, the mastication ability was higher in OG at 7 days postoperatively, but there was no difference between groups at 6 months postoperatively (P > 0.05). Conclusion: Complex mandibular impacted teeth can easily induce pericoronitis, so clinicians should pay attention to the influencing factors of pericoronitis. Minimally invasive surgery for complex impacted mandibular teeth can effectively improve treatment outcomes, accelerate patient rehabilitation, and provide more effective protection for patients' oral health and masticatory ability, which is worth promoting in clinical use.

Emission profiles, ozone formation potential and health-risk assessment of volatile organic compounds in rubber footwear industries in China.

The emission characteristics of VOCs in the rubber footwear industry (RFI) and its effect on human health are poorly understood to date. Herein, up to 68 VOCs, sorted into seven classes including alkanes, alkenes, acetylene, aromatics, halocarbons, carbon disulfide, and oxygenated VOCs, were monitored. VOCs emitted from three main processing stages of RFI, including shaping, painting and vulcanizing, were 383, 1507 and 1026 mg/m3, respectively. The top 10 VOCs contributing to the concentration and ozone formation potential were identified. Generally, alkanes were the major component emitted from three stages, contributing 48.58%-63.07% of the total VOCs. Alkenes contributed most to the OFP, accounting for 37.2%-69.1%. Based on the risk assessment, a definite cancer risk for workers in shaping workshop should be noticed. Several VOCs with a life carcinogenic risk higher than 10-4, especially benzene, bromodichloromethane, ethylbenzene and 1,1,2-trichloroethane, should be focused on. Therefore, more attention should be taken for the extended-ranges of VOCs in subordinate RFI, except for the publicly concerned aromatics in rubber industry. A VOCs emission inventory from the production process of Chinese RFI in 2000-2016 was compiled. It is estimated that Chinese RFIs have emitted a total of 319 × 104 t VOCs in those past 17 years.

Polychlorinated dibenzo-p-dioxins and dibenzofurans in eggs of eight avian species from Dongting Lake, China.

Concentrations of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) were determined in eggs of eight avian species collected from Dongting Lake of China to assess residue levels, accumulation patterns, and toxic potential in different avian species. Concentrations of total 2,3,7,8-substituted PCDD/Fs were in the range of 10.8-182pgg(-1) lipid weight. Eggs of great egret and lesser pied kingfisher contained higher levels of PCDD/Fs than eggs of other species, indicating the specific exposure and accumulation of PCDD/Fs relating to feeding habits and the life span. PCDD/Fs congener patterns varied among species. The patterns of PCDD/Fs in the eggs may be influenced by feeding habits, specific elimination, and metabolism. In general, concentrations of PCDDs were higher than those of PCDFs in avian eggs. On basis of lipid weight, total 2,3,7,8-TCDD toxic equivalents (TEQs) calculated based on the WHO TEFs for birds ranged from 2.04 to 42.0pgg(-1); and on basis of wet weight, total WHO-TEQs ranged from 0.19 to 1.59pgg(-1). 2,3,7,8-TCDF, 2,3,4,7,8-PeCDF, 2,3,7,8-TCDD, 1,2,3,7,8-PeCDD were the major contributors to TEQ concentration in most avian eggs, whereas 1,2,3,4,7,8-HxCDD also accounted for a major portion of TEQs in eggs of azure-winged magpie. Values of TEQs in avian eggs were lower than toxic threshold values, implying risk reduction and natural restoration of PCDD/Fs contamination in Dongting Lake region.

Speciation analysis of arsenic in traditional Chinese medicines by hydride generation-atomic fluorescence spectrometry.

A method has been described for the determination of arsenic species (arsenite and arsenate) by hydride generation-atomic fluorescence spectrometry (HG-AFS). The experimental conditions that influence the fluorescence intensity and the reduction of arsenic were investigated and optimized, and the influences from foreign ions and their elimination were studied. The detection limit was found to be 79.7 ng L(-1). The proposed method was applied to the determination of arsenic species in water leachate of traditional Chinese medicines with a recovery range of 91.1-109.5%.

Spatial and seasonal distributions of polychlorinated dibenzo-p-dioxins and dibenzofurans and polychlorinated biphenyls around a municipal solid waste incinerator, determined using polyurethane foam passive air samplers.

Twenty-six ambient air samples were collected around a municipal solid waste incinerator (MSWI) in the summer and winter using polyurethane foam passive air samplers, and analyzed to assess the spatial and seasonal distributions of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs). Three stack gas samples were also collected and analyzed to determine PCDD/F (971 pg m(-3) in average) and PCB (2,671 pg m(-3) in average) emissions from the MSWI and to help identify the sources of the pollutants in the ambient air. The total PCDD/F concentrations in the ambient air samples were lower in the summer (472-1,223 fg m(-3)) than the winter (561-3913 fg m(-3)). In contrast, the atmospheric total PCB concentrations were higher in the summer (716-4,902 fg m(-3)) than the winter (489-2,298 fg m(-3)). Principal component analysis showed that, besides emissions from the MSWI, the domestic burning of coal and wood also contributed to the presence of PCDD/Fs and PCBs in the ambient air. The PCDD/F and PCB spatial distributions were analyzed using ordinary Kriging Interpolation and limited effect was found to be caused by emissions from the MSWI. Higher PCDD/F and PCB concentrations were observed downwind of the MSWI than in the other directions, but the highest concentrations were not to be found in the direction with the greatest wind frequency which might be caused by emissions from domestic coal and wood burning. We used a systemic method including sampling and data analysis method which can provide pioneering information for characterizing risks and assessing uncertainty of PCDD/Fs and PCBs in the ambient air around MSWIs in China.