An Environmental Dilemma for China During the COVID-19 Pandemic: The Explosion of Disposable Plastic Wastes

Plastic pollution control has been on top of the political agenda in China. In January 2020, China announced a phased ban on the production and usage of various types of single-use plastics as a solution to environmental pollution problems. However, the outbreak of COVID-19 seems to be a new obstacle to the ban on single-use plastic products. To basically satisfied the daily necessities and contain the spread of SARS-CoV-2 under the background of the regular epidemic prevention and control in China, online ordering, contactless delivery and wearing mask have become an important and feasible way of daily life. However, the unrestrained use of disposable plastic bags, lunch boxes and masks within the nationwide quarantine leads to hundreds of millions of plastics wastes every day. The potential environmental pollution caused by the use of disposable plastic products during the pandemic should arouse social concern. The Chinese government should manage environmental protection in parallel with anti-pandemic endeavors as the situation of the pandemic evolves.

     

暴露组学的概念与应用

暴露组学作为基因组学的补充是指从妊娠开始贯穿整个人生的环境暴露(包括生活方式因素)。暴露源包括外源(污染、辐射、饮食等)和内源(炎症、感染、微生物等)。继全基因组关联研究(GWAS)之后发展的全暴露组关联研究(EWAS)的目的是对在未知方式下暴露的评估。EWAS方法通过比较患者和健康受试者暴露组的分析结果,确定有效的生物标志物,进而利用这些生物标志物来阐明暴露-效应关系(生化流行病学)、暴露和人体动力学来源(暴露生物学),以及作用机制(系统生物学)。"自下而上"和"自上而下"的方法在识别个体暴露上都具有科学价值。"自上而下"法用于揭示人类疾病的未知暴露源,而"自下而上"法是用于分析外暴露以及建立干预与预防的方法。生物标志物不仅可以用于研究外暴露,也可以用于研究内暴露。内暴露组学采用组学的方法进行研究,如基因组学、蛋白质组学、表观基因组学、代谢组学、转录组学、加合物组学等。人类生命早期暴露组学(HELIX)项目是近期启动的描述欧洲人群的早期暴露以及揭示组学标志物和儿童时期健康关系的第一次尝试。该文介绍了其研究方法、工具、思路及其重要意义,同时总结了暴露组学从概念到应用可能面临的挑战。     

The Cellular Toxicity of PM2.5 Emitted from Coal Combustion in Human Umbilical Vein Endothelial Cells

ObjectiveTo explore the relationship between different components offineparticulate matter (PM2.5) emitted from coal combustion and their cytotoxic effect in the vascular endothelial cells. MethodsCoal-fired PM2.5was sampled using a fixed-source dilution channel and flow sampler. The sample components were analyzed by ion chromatography and inductively coupled plasma atomic emission spectroscopy(ICP-AES). The PM2.5suspension was extracted using an ultrasonic water-bath method and thenhuman umbilical vein endothelial cells (EA.hy926) were treated withvarious concentrations of the PM2.5 suspension. Cell proliferation,oxidativeDNA damage, and global DNA methylation levelswere used to measurethe cellulartoxicity of PM2.5emitted fromcoalcombustion. ResultsComparedtoothertypesof coal-fired PM2.5preparations,thePM2.5 suspension from Yinchuan coal had the highest cytotoxicity.PM2.5 suspension from Datong coal hadthe highest toxic effectwhile that fromYinchuan coal had the lowest.Exposure to coal-fired PM2.5 from Jingxi coalresulted inlower 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels. At the same dose, PM2.5 emitted from coal combustion could produce more severeDNAimpairmentcompared to that produced by carbon black.Cell survival rate was negatively correlated with chloride and potassiumionscontent.The5-methylcytosine(5-mC) level waspositively correlated withMnandnegatively correlated withZn levels.The 8-OHdG% level was positively correlated withboth MnandFe. ConclusionPM2.5 emitted from coal combustion can decrease cell viability, increase global DNA methylation, and causeoxidativeDNA damage inEA.hy926 cells. Metalcomponentsmay be important factors that influence cellular toxicity.     

Changes in Spectral Characteristics and Copper (II)-Binding of Dissolved Organic Matter in Leachate from Different Water-Treatment Processes

The aim of the present study was to investigate the fluorescence properties of dissolved organic matter (DOM) from four leachate samples, which were disposed by regulating tank (RTK), anaerobic treatment (ATT), oxidation ditch (ODH), and membrane bioreactor and to assess their binding capacities and stability constants by Cu(II). The results showed that five fluorescent peaks, including three humic-like peaks (peaks A, C, and E) and two protein-like peaks (peaks B and D), were identified. Most fluorescent components can be degraded after ODH. Fluorescence-quenching titration showed that the modified Stern–Volmer model can be used to fit the quenching data and calculate conditional stability constants (log K) and the % of fluorophores (f %) between DOM and Cu(II). DOM–Cu(II) complexes had relatively high log K values in the RTK and ATT disposals. After the ODH-treatment process, log K values showed a marked decrease. The f % values of protein-like materials were evidently greater than those of humic-like substances. The results showed the impact of the water treatment on the metal-binding ability of various fractions.     

Enhanced nitrite accumulation under mainstream conditions by a combination of free ammonia-based sludge treatment and low dissolved oxygen: reactor performance and microbiome analysis

Partial nitritation under mainstream conditions is one of the major bottlenecks for the application of deammonification processes to municipal wastewater treatment plants. This study aimed at evaluating the combination effect of a side-stream free ammonia (FA) treatment and low dissolved oxygen (0.2 ± 0.1 mg L⁻¹) on inhibiting nitrite oxidizing bacteria (NOB) from enhancing nitrite accumulation in long-term lab-scale experiments. Two continuous floccular sludge reactors treating low-strength synthetic wastewater (60 mg N–NH₄⁺ L⁻¹ without COD) with a fixed nitrogen loading rate of 0.22 ± 0.03 g N per L per day were operated in a varied temperature range of 7–31 °C, with one acting as the experimental reactor and the other as the control. Side-stream sludge treatment with a stepwise elevation of FA concentration (65.2–261.1 mg NH₃ L⁻¹) was carried out every day in the experimental reactor; the nitrite accumulation ratio (NAR, (NO₂–N/(NO₂⁻–N + NO₃⁻–N) × 100%)) in the experimental reactor was always about twice that in the control one. Quantitative PCR (q-PCR) and high-throughput sequencing analyses showed the dominant NOB was mostly Nitrobacter, while there was an alternating trend between Nitrobacter and Nitrospira. Even though the whole microbial communities of each experimental stage between the two reactors were relatively clustered due to an incomplete NOB washout, three abundant metabolisms (amino acid metabolism, pyruvate metabolism and nitrogen metabolism) and key functional genes of nitrification predicted by PICRUSt in the experimental reactor were enriched, providing a better understanding of nitrite accumulation. These results have demonstrated that the positive hybrid effects of FA side-stream sludge treatment and a low DO could enhance nitrite accumulation. It is expected that a complete washout of NOB would be achieved after further process optimization.

An introduction of the combination of side-stream sludge treatment using FA and low DO could more effectively enhance nitrite accumulation than single low DO.     

Vanadium exposure-induced neurobehavioral alterations among Chinese workers

Vanadium-containing products are manufactured and widely used in the modern industry. Yet the neurobehavioral toxicity due to occupational exposure to vanadium remained elusive. This cross-sectional study was designed to examine the neurotoxic effects of occupational vanadium exposure. A total of 463 vanadium-exposed workers (exposed group) and 251 non-exposed workers (control group) were recruited from a Steel and Iron Group in Sichuan, China. A WHO-recommended neurobehavioral core test battery (NCTB) and event-related auditory evoked potentials test (P300) were used to assess the neurobehavioral functions of all study subjects. A general linear model was used to compare outcome scores between the two groups while controlling for possible confounders. The exposed group showed a statistically significant neurobehavioral alteration more than the control group in the NCTB tests. The exposed workers also exhibited an increased anger-hostility, depression-dejection and fatigue-inertia on the profile of mood states (p < 0.05). Performances in the simple reaction time, digit span, benton visual retention and pursuit aiming were also poorer among exposed workers as compared to unexposed control workers (p < 0.05). Some of these poor performances in tests were also significantly related to workers’ exposure duration. P300 latencies were longer in the exposed group than in the control (p < 0.05). Longer mean reaction times and more counting errors were also found in the exposed workers (p < 0.05). Given the findings of our study and the limitations of neurobehavioral workplace testing, we found evidence of altered neurobehavioral outcomes by occupational exposure to vanadium.