Pollutants

污染物
  • 文章类型: Journal Article
    该研究旨在仔细审查与咖啡生产链相关的化学危害,以分析消费者和环境的风险和机会,以及识别潜在的知识差距。从1949年到2024年4月,咨询了Scopus数据库以进行文献计量分析。因此,共分析了680篇文章。结果表明,自2015年以来,研究活动大幅增加。中国,巴西,美国是科学生产和合作的主要国家。这个领域最多产的期刊是化学领域,全面环境的科学,食品化学,农业与食品化学学报,和环境管理杂志,所有这些都在第一个四分位数。单词分析揭示了两个主要主题:第一个主题是咖啡的化学危害及其对健康的影响,第二部分探讨了咖啡生产过程中产生的废物及其再利用的潜力。研究涉及的主题包括咖啡的成分,相关的化学危害,可能的健康风险,以及将废物用于环境保护的方法。未来的研究应该集中在优化技术和过程,以确保质量,安全,和可持续性。
    The research aimed to carefully review the chemical hazards linked to the coffee production chain to analyse the risks and opportunities for consumers and the environment, as well as identify potential knowledge gaps. The Scopus database was consulted from 1949 to April 2024 to conduct a bibliometric analysis. As a result, 680 articles were analysed. Results indicated a significant increase in research activity since 2015. China, Brazil, and the USA were the leading countries in scientific production and collaborations. The most prolific journals in this field were Chemosphere, Science of the Total Environment, Food Chemistry, Journal of Agricultural and Food Chemistry, and Journal of Environmental Management, all of which are in the first quartile. The word analysis revealed two main themes: the first focuses on the chemical hazards of coffee and their impact on health, while the second explores the waste generated during coffee production and its potential for reuse. The topics covered in the research include the composition of coffee, associated chemical hazards, possible health risks, and ways to reuse waste for environmental protection. Future research should concentrate on optimising techniques and processes to ensure quality, safety, and sustainability.
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  • 文章类型: Journal Article
    在非洲的撒哈拉以南地区,在许多国家,获得安全饮用水的机会仍然有限。这项研究概述了马达加斯加农村和城市周边地区的地表水和地下水质量,乌干达,卢旺达。选定的物理化学参数,无机物(包括无机离子),和有机污染指标,如总有机碳,非离子表面活性剂,阳离子表面活性剂,阴离子表面活性剂,酚类化合物和甲醛的总和,进行了分析。主成分分析用于评估水质的变异性并确定区域依赖性。大多数研究样品中的无机离子成分符合世卫组织和欧盟对用于人类消费的饮用水的要求,并且不构成人类健康风险。然而,硝酸盐的个体非致癌健康指数和水质指数显示摄入研究的饮用水可能存在威胁。表面活性剂(0.1-0.65mgL-1)的存在,酚类化合物(0.025-1.76mgL-1)和甲醛(0.04-0.32mgL-1)也可能对人类构成风险,动物,和水生生物。此外,在马达加斯加(2022年)的最后一次野外活动期间对大肠杆菌和总大肠杆菌进行的原位测量显示,所有研究的饮用水源从中等风险到不安全不等.这一结果要求迫切需要加强WASH(水,卫生,和卫生)研究地区的服务。化学和微生物污染物的存在表明,地方当局需要制定和实施流域管理计划,以确保保护水资源免受潜在污染,并提高社区对人类活动对水资源影响的认识。
    In the sub-Saharan region of Africa, access to safe drinking water remains limited in many countries. This study provides an overview of the quality of surface water and groundwater in rural and peri-urban areas of Madagascar, Uganda, and Rwanda. Selected physico-chemical parameters, inorganic species (including inorganic ions), and organic pollution indicators, such as total organic carbon, non-ionic surfactants, cationic surfactants, anionic surfactants, sum of phenolic compounds and formaldehyde, were analysed. Principal component analysis was applied to assess the variability of the water quality and identify regional dependencies. The inorganic ion composition in the majority of the studied samples meets WHO and EU requirements for drinking water intended for human consumption and poses no human health risk. However, an individual non-cancer-causing health index for nitrates and the values of Water Quality Index show a possible threat of ingesting the studied drinking water. The presence of surfactants (0.1-0.65 mgL-1), phenolic compounds (0.025-1.76 mgL-1) and formaldehyde (0.04-0.32 mgL-1) may also pose a risk to human, animal, and aquatic life. Additionally, in-situ measurements for E. coli and Total Coliforms conducted during the last field campaign in Madagascar (2022) revealed that all studied drinking water sources ranged from intermediate risk to unsafe. This result calls for the urgent need to enhance WASH (water, sanitation, and hygiene) services in the studied areas. The presence of both chemical and microbiological pollutants shows the need for the local authorities to develop and implement a catchment management plan to ensure the protection of water resources from potential pollution, and raise community awareness about the impact of human activity on water resources.
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  • 文章类型: Journal Article
    河流发电厂(ROR)代表了全球大多数水力发电厂。它们对环境的影响没有充分的记录,据信是有限的,特别是关于甲基汞(MeHg)对食物网的污染,一种神经毒素.ROR通常安装在小河流中,流域干扰与大坝建设的综合影响会使环境管理复杂化。我们报告了一项关于圣莫里斯河(加拿大)的多年案例研究,在建造了两个ROR植物后,观察到捕食者鱼中甲基汞积累的暂时增加。相关的池塘充当了受森林大火和伐木干扰的流域中汞(Hg)和有机物的沉积盆地。这种新鲜的有机碳可能推动了微生物甲基汞的生产。与汞的存在相比,汞甲基化与环境条件更相关,并鉴定了主要的甲基化微生物群。人工湿地是汞甲基化的重要部位,但不是鱼类汞增加的主要来源。有机碳降解是食物链底部甲基汞积累的主要驱动因素,而营养水平解释了食物链顶部的变化。总的来说,碳循环是该系统中汞动力学的关键驱动因素,和ROR植物可能会导致暂时的(大约12年)在受干扰的流域发展时,食物网中的汞增加,尽管这一增幅小于大型水库。未来ROR建设的建议是建立具有初始高时间分辨率的良好环境监测计划,并在计划中考虑近期和潜在的流域干扰。
    Run-of-river power plants (ROR) represent the majority of hydroelectric plants worldwide. Their environmental impacts are not well documented and are believed to be limited, particularly regarding the contamination of food webs by methylmercury (MeHg), a neurotoxin. RORs are typically installed in small rivers where combined effects of watershed disturbances with dam construction can complicate environmental management. We report a multi-year case study on the Saint-Maurice River (Canada) where an unpredicted temporary increase in MeHg accumulation in predator fish was observed after the construction of two ROR plants. The associated pondages acted as sedimentation basins for mercury (Hg) and organic matter from a watershed disturbed by a forest fire and by logging. This fresh organic carbon likely fueled microbial MeHg production. Hg methylation was more associated with environmental conditions than to the presence of Hg, and main methylating microbial groups were identified. A constructed wetland was a site of significant Hg methylation but was not the main source of the fish Hg increase. Organic carbon degradation was the main driver of MeHg accumulation at the base of the food chain whereas trophic levels explained the variations at the top of the food chain. Overall, carbon cycling was a key driver of Hg dynamics in this system, and ROR plants can cause temporary (ca. 12 years) Hg increase in food webs when developed in disturbed watersheds, although this increase is smaller than for large reservoirs. Recommendations for future ROR construction are to establish a good environmental monitoring plan with initial high temporal resolution and to consider recent and potential watershed disturbances in the plan.
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  • 文章类型: Journal Article
    背景:接触火山喷发过程中释放的气体和颗粒物可能会对人群健康有害。本文报告了ASHES研究的初步结果,旨在确定2021年拉帕尔马岛(西班牙)火山喷发对没有先前呼吸道疾病的成年人群的呼吸道健康影响。
    方法:对健康成年人群进行综合队列研究。考虑了三个暴露组:第1组,高暴露;第2组,中度暴露;第3组,轻度或无暴露。我们对喷发期间和之后的症状进行了描述性分析,以及测量喷发后的肺功能(通过强制肺活量和一氧化碳的扩散能力)。
    结果:分析包括474名受试者:第1组54名,第2组335名,第3组85名。在喷发期间暴露的组中观察到大多数症状的显着增加。喷发之后,这种增加仍然存在一些症状。似乎有剂量反应关系,这样曝光越高,赔率比越高。在组1中13.0%的受试者、组2中8.6%的受试者和组3中7.1%的受试者中观察到<70%的支气管扩张剂前FEV1/FVC比率。
    结论:这项研究首次报道了接触火山喷发与成人症状之间的剂量反应关系。此外,暴露量较高的个体有阻塞性损害的趋势。
    BACKGROUND: Exposure to gases and particulate matter released during volcanic eruptions can prove harmful to population health. This paper reports the preliminary results of the ASHES study, aimed at ascertaining the respiratory health effects of the 2021 volcanic eruption in La Palma Island (Spain) on the adult population without previous respiratory disease.
    METHODS: Ambispective cohort study on the healthy adult population. Three exposure groups were considered: Group 1, high exposure; Group 2, moderate exposure; and Group 3, minor or no exposure. We carried out a descriptive analysis of symptoms during and after the eruption, as well as measure lung function after the eruption (through forced spirometry and diffusing capacity of carbon monoxide).
    RESULTS: The analysis included 474 subjects: 54 in Group 1, 335 in Group 2, and 85 in Group 3. A significant increase in most symptoms was observed for subjects in the groups exposed during the eruption. After the eruption, this increase remained for some symptoms. There seems to be a dose-response relationship, such that the higher the exposure, the higher the odds ratio. A prebronchodilator FEV1/FVC ratio<70% was observed in 13.0% of subjects in Group 1, 8.6% of subjects in Group 2, and 7.1% of subjects in Group 3.
    CONCLUSIONS: This study is the first to report a dose-response relationship between exposure to volcanic eruptions and the presence of symptoms in adults. Furthermore, there is a tendency toward obstructive impairment in individuals with higher exposure.
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  • 文章类型: Journal Article
    2019年冠状病毒病(COVID-19),由严重急性呼吸道综合症冠状病毒2(SARS-CoV-2)引起,2019年12月在武汉市爆发,在中国湖北省。从那以后,它几乎传遍了全世界,扰乱许多人类活动。在温带气候中,压倒性的证据表明,在寒冷季节,其发病率显着增加。意大利是最早的国家之一,其中COVID-19达到了流行病的比例,已经在2020年初。因此,有足够的数据对病毒传播与环境条件之间的相关性进行系统的调查。这项研究的目的是调查病毒扩散与天气之间的关系,包括温度,风,湿度和空气质量,在推出任何疫苗之前,包括污染物的快速变化(不仅是文献中报道的长期影响)。关于他们的方法论,考虑到问题的复杂性和数据的稀疏性,基于排名(Spearman和Kendall相关系数)和创新的动态系统分析技术(复发图)的强大统计工具已被部署来解开不同的影响。在结果方面,证据表明,即使温度起着根本的作用,COVID-19的发病率还取决于其他因素。在主要城市的总体水平上,空气污染和影响空气污染的环境数量,特别是风的强度,没有可忽略的影响。这些证据应该促使人们重新思考与遏制此类空气传播传染病有关的公共政策,特别是信息收集和交通管理。
    The coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), broke out in December 2019 in Wuhan city, in the Hubei province of China. Since then, it has spread practically all over the world, disrupting many human activities. In temperate climates overwhelming evidence indicates that its incidence increases significantly during the cold season. Italy was one of the first nations, in which COVID-19 reached epidemic proportions, already at the beginning of 2020. There is therefore enough data to perform a systematic investigation of the correlation between the spread of the virus and the environmental conditions. The objective of this study is the investigation of the relationship between the virus diffusion and the weather, including temperature, wind, humidity and air quality, before the rollout of any vaccine and including rapid variation of the pollutants (not only their long term effects as reported in the literature). Regarding them methodology, given the complexity of the problem and the sparse data, robust statistical tools based on ranking (Spearman and Kendall correlation coefficients) and innovative dynamical system analysis techniques (recurrence plots) have been deployed to disentangle the different influences. In terms of results, the evidence indicates that, even if temperature plays a fundamental role, the morbidity of COVID-19 depends also on other factors. At the aggregate level of major cities, air pollution and the environmental quantities affecting it, particularly the wind intensity, have no negligible effect. This evidence should motivate a rethinking of the public policies related to the containment of this type of airborne infectious diseases, particularly information gathering and traffic management.
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  • 文章类型: Journal Article
    这项研究开发了一种新型的人工湿地(CW)与磁场相结合,用于处理生活污水,并通过有限元方法对磁场分布进行了求解和优化。在这里,我们研究了优化磁场优化的影响,并研究了其对CW处理性能和微生物群落响应的影响。优化结果表明,CW单元的平均磁场强度从3mT增加到8mT,磁场强度大于5mT的区域比例也从30%增加到74%。水质分析结果表明,磁场(平均3mT)对化学需氧量(COD)和NH4+-N(p<0.01)的去除率显著提高,分别增长12.2%和8.49%,分别。此外,M-VFCW(O)(平均8mT)对COD和NH4-N(p<0.01)的去除效果更明显,分别增长15.58%和49.1%,分别。磁场的施加显着改变了CW中优势细菌的丰度。变形杆菌等优势菌的相对丰度(63.3%),在M-VFCW(O)中,厚壁菌(4.72%)和放线菌(2.11%)在有机物去除和硝化反硝化相关细菌中具有重要作用,例如Nitrosirae(1.48%)和Planctomycetes(9.58%)。这些结果表明,在CW中引入磁场可以通过生物过程改善有机物和氮的去除。磁场的优化对提高VFCW的性能具有重要意义。
    This study developed a novel constructed wetland (CW) coupled with a magnetic field for treating domestic wastewater, and the magnetic field distribution was solved and optimised by the finite element method. Herein, we investigated the effects of optimising magnetic field optimisation and studied its impact on CW treatment performance and the responses of a microbial community. The optimisation results showed that the average magnetic field strength of the CW unit increases from 3 to 8 mT, and the proportion of areas with magnetic field strength greater than 5 mT also increases from 30% to 74%. The water quality analysis results showed that the removal of chemical oxygen demand (COD) and NH4+-N (p < 0.01) was significantly increased by the magnetic field (average 3 mT), increasing by 12.2% and 8.49%, respectively. Moreover, the removal of COD and NH4+-N (p < 0.01) was more significantly increased by M-VFCW(O) (average 8 mT), increasing by 15.58% and 49.1%, respectively. The magnetic field application shifted significantly the abundance of dominant bacteria in CWs. Relative abundance of dominant bacteria such as Proteobacteria (63.3%), Firmicutes (4.72%) and Actinobacteria (2.11%) that played an important role in organics removal and nitrification and denitrification-related bacteria such as Nitrospirae (1.48%) and Planctomycetes (9.58%) significantly promoted in M-VFCW(O). These results suggest that introducing a magnetic field into CWs may improve organics and nitrogen removal via the biological process, and the optimisation of the magnetic field was significant in enhancing the performance of VFCWs.
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  • 文章类型: Journal Article
    饮用水中的重金属(loid)(HM)和消毒副产物(DBPs)对人体健康构成风险,并危害饮用水。水相关行为在不同年龄段和地区之间存在显着差异。在这项研究中,HMs的致癌和非致癌风险(As,Cd,Cr6+,Cu,Pb,和Zn)和DBPs(溴二氯甲烷(BDCM),溴仿,氯仿,二溴氯甲烷(DBCM),二氯乙酸(DCAA),通过多种暴露途径评估了两个中国大城市(华北的北京和华南的广州)饮用水中的三氯乙酸(TCAA))。结果显示,9个月至2岁儿童的总致癌风险(TCR)和危害指数(HI)高于可接受水平,表明尽管选定的特大城市的饮用水水质符合现行的中国国家标准(GB5749-2022),不应忽视当地幼儿在饮用水中暴露于HMs和DBP的健康风险。具体来说,<18岁儿童在饮用水中暴露于As的致癌风险(CR),他们被分成不同的年龄组,比北京和广州的DBP暴露的TCR高1.5-2.0-和4.5-5.9-倍,分别。关于9个月至2岁的儿童,TCAA暴露占北京饮用水中DBP接触TCR的比例最大(35.6%),比广州高5.4倍;然而,广州饮用水中DBP暴露的TCR主要是由氯仿暴露引起的,占TCR的40.6%,是北京的1.5倍。此外,两个特大城市饮用水中DCAA暴露的CR占9个月至2岁儿童TCR的很大比例。蒙特卡罗模拟表明,饮用水中同时暴露于As和DBPs的TCR的62.2%和42.6%超过了敏感人群的可接受水平,也就是说,北京1-2岁儿童(第95百分位数=4.2×10-4)和广州9-12个月儿童(第95百分位数=5.2×10-4),分别。这种精心的健康风险评估为改善水质指标以保证中国的饮用水安全提供了启示。
    Heavy metal(loid)s (HMs) and disinfection by-products (DBPs) in drinking water pose risks to human health and jeopardize drinking water. Water-related behaviors vary significantly among different age groups and regions. In this study, the carcinogenic and non-carcinogenic risks of HMs (As, Cd, Cr6+, Cu, Pb, and Zn) and DBPs (bromodichloromethane (BDCM), bromoform, chloroform, dibromochloromethane (DBCM), dichloroacetic acid (DCAA), and trichloroacetic acid (TCAA)) in drinking water in two Chinese megacities (Beijing in North China and Guangzhou in South China) via multiple exposure pathways were assessed. The results showed that children aged 9 months to 2 years had a total carcinogenic risk (TCR) and hazard index (HI) above acceptable levels, indicating that despite the drinking water quality in the selected megacities meeting the current Chinese national standards (GB 5749-2022), the health risks of exposure to HMs and DBPs in drinking water for local young children should not be neglected. Specifically, the carcinogenic risk (CR) of exposure to As in drinking water for children < 18-years-old, who were divided into different age groups, was 1.5-2.0- and 4.5-5.9-times higher than the TCR of exposure to DBPs in Beijing and Guangzhou, respectively. Regarding children aged 9 months to 2 years, the exposure to TCAA accounted for the largest proportion (35.6 %) of the TCR of exposure to DBPs in Beijing drinking water, 5.4-times higher than that in Guangzhou; whereas, the TCR of exposure to DBPs in Guangzhou drinking water was predominantly caused by exposure to chloroform, accounting for 40.6 % of the TCR and 1.5-times higher than that in Beijing. In addition, the CR of exposure to DCAA in drinking water in both megacities accounted for a large proportion of the TCR for children aged 9 months to 2 years. Monte Carlo simulations showed that 62.2 % and 42.6 % of the TCR of simultaneous exposure to As and DBPs in drinking water exceeded the acceptable level for sensitive populations, that is, children aged 1-2 years in Beijing (95th percentile = 4.2 × 10-4) and children aged 9-12 months in Guangzhou (95th percentile = 5.2 × 10-4), respectively. This elaborate health risk assessment sheds light on improving the water quality indices to guarantee drinking water safety in China.
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  • 文章类型: Journal Article
    背景:由于其对人类健康和环境的广泛负面影响,从废水中去除重金属离子已成为全球关注的问题。密度泛函理论用于研究去除Pb2的可能性,Hg2+,使用纳米石墨烯从废水中提取Cd2+离子。研究人员已经表明,NG可以有效地从介质中去除重金属。此外,结果表明,Pb2+的吸附,Hg2+,和Cd2+离子可能会减少大的原始NG(HOMO-LUMO)间隙。
    方法:HSE06可以准确表示NG电特性。DFT-D3方法也用于解释本研究中的范德华相互作用。结果表明,阳离子-NG系统中的电荷转移和结合能保持更大的电子转移速率。Pb2+,Hg2+,和Cd2+吸附结果表明Egap显著降低了68%,15%,21%,分别。Pb2+@NG络合物表现出最强的振荡器强度。这可以通过C原子的2px轨道与Pb2阳离子的6s轨道之间的巨大占用数差来解释。Pb2+@NG的较大Ebin值与增加的预测红移(199nm)一致。依赖于时间的DFT(杂化功能HSE06)研究表明,相关的配合物具有“配体到金属的电荷转移”激发。总的来说,发现Pb2+@NG的k值最大,结合能,红移,和复合物之间的电荷转移速率。这项研究的理论见解可能会影响实验工作,以确定有效和高效地从废水中去除污染物的基于NG的化合物。
    BACKGROUND: Heavy metal ion removal from wastewater has become a global concern due to its extensive negative effects on human health and the environment. The density functional theory is employed to investigate the possibility of removing Pb2+, Hg2+, and Cd2+ ions from wastewater using nano-graphene. Researchers have shown that NG can efficiently remove heavy metals from media. Additionally, it was shown that the adsorption of Pb2+, Hg2+, and Cd2+ ions might reduce the large pristine NG (HOMO-LUMO) gap.
    METHODS: HSE06 may accurately represent NG electrical characteristics. The DFT-D3 method was also used to account for Van der Waals interactions in the present study. The results demonstrated that charge transfer and binding energy remained greater in cation-NG systems with greater electron transfer rates. Pb2+, Hg2+, and Cd2+ adsorption results indicated that Egap was significantly reduced by 68%, 15%, and 21%, respectively. The Pb2+@NG complex exhibited the strongest oscillator strength. This may be explained by the enormous occupation number difference between the 2px orbital of the C atoms and the 6 s orbital of the Pb2+ cations. The greater Ebin value of Pb2+@NG is consistent with the increased predicted redshifts (199 nm). DFT (hybrid functional HSE06) studies that rely on time showed that the relevant complexes have \"ligand-to-metal charge transfer\" excitations. In general, it was found that Pb2+@NG had the greatest k value, binding energy, redshifts, and charge transfer rate among the complexes. The theoretical insights of this study may influence experimental efforts to identify NG-based compounds that are effective and efficient at removing pollutants from wastewater.
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  • 文章类型: Journal Article
    本研究旨在评估在埃及泰坦亚历山大波特兰水泥公司使用不同燃料对污染物排放和浓度(总悬浮颗粒(TSP),二氧化氮(NO2),和二氧化硫(SO2))以及它们对2014-2020年期间环境空气质量的影响使用AERMOD扩散模型。结果表明,将2014年的天然气燃料改为与替代燃料混合的煤(轮胎衍生燃料(TDF),干污泥(DSS),和垃圾衍生燃料(RDF))在2015-2020年导致污染物排放和浓度的波动变化。TSP的最高和最低最大浓度分别发生在2017年和2014年。其中TSP与煤呈正相关,RDF,和DSS,与天然气呈负相关,柴油,和TDF。此外,最低和最高的NO2浓度分别在2020年和2016年检测到,其次是2017年,其中NO2与DSS呈正相关,与TDF呈负相关,并随柴油变化,煤炭,和RDF。此外,SO2的最大浓度在2018年最低,2016年最高,其次是2017年,因为它与天然气和DSS相当正相关,与RDF负相关,TDF,和煤炭。一般来说,发现随着DSS百分比的降低,TDF和RDF的百分比增加,柴油,和煤炭将减少污染物的排放和浓度,并改善环境空气质量。
    This study aims to assess the impact of using different fuels in Egyptian Titan Alexandria Portland Cement Company on emissions and concentrations of pollutants (Total suspended particles (TSP), nitrogen dioxide (NO2‎), and sulfur dioxide (SO2)) and their influence on ambient air quality during the period 2014-2020 using AERMOD dispersion model. The results showed that changing the fuel from natural gas in 2014 to coal mixed with alternative fuels (Tire-Derived Fuel (TDF), Dried Sewage Sludge (DSS), and Refuse Derived Fuels (RDF)) in 2015-2020 caused fluctuating variations in pollutant emissions and concentrations. The highest and lowest maximum concentrations of TSP occurred in 2017 and 2014 respectively, where the TSP is positively correlated with coal, RDF, and DSS and negatively correlated with natural gas, diesel, and TDF. Also, the lowest and highest maximum NO2 concentrations were detected in 2020 and 2016 followed by 2017 respectively, where NO2 is positively correlated with DSS and negatively correlated with TDF and varies with diesel, coal, and RDF. Moreover, the maximum concentrations of SO2 were the lowest in 2018 and highest in 2016 followed by 2017 because of its considerable positive correlation with natural gas and DSS and negative correlation with RDF, TDF, and coal. Generally, it was found that increasing the percentage of TDF and RDF with decreasing the percentage of DSS, diesel, and coal will reduce pollutant emissions and concentrations and enhance ambient air quality.
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  • 文章类型: Journal Article
    异源生物的酶催化代谢生物转化在毒理学演变和随后的环境健康风险评估中起着重要作用。最近的研究指出,第一阶段人类黄素依赖性单加氧酶(例如,FMO3)可以催化异源生物转化为更有毒的代谢产物。然而,代谢机制的细节不足。为了填补缺口中的机制,进行了系统密度泛函理论计算,以阐明对环境污染物的各种FMO催化氧化反应,包括反硝化(例如,硝基苯酚),N-氧化(例如,尼古丁),脱硫(例如,fonofos),和脱卤(例如,五氯苯酚)。类似于细胞色素P450的活性中心化合物0,FMO主要催化具有三环异咯嗪C-4a-过氧化氢(FADHOOH)结构的反应。正如将要显示的,FMO催化的途径比逐步机制更有利;去质子化是引发酚类底物氧化反应的必要条件;FMO对尼古丁的区域选择性更喜欢N-氧化,而不是N-去甲基化途径;P-S-O三角环的形成是FMO对fonofos脱硫的关键步骤。我们设想FMO用计算方法催化的这些基本机制可以扩展到其他类似结构的异种生物,这可能有助于高通量筛选,并在未来提供理论预测。
    The enzyme-catalyzed metabolic biotransformation of xenobiotics plays a significant role in toxicology evolution and subsequently environmental health risk assessment. Recent studies noted that the phase I human flavin-dependent monooxygenase (e.g., FMO3) can catalyze xenobiotics into more toxic metabolites. However, details of the metabolic mechanisms are insufficient. To fill the mechanism in the gaps, the systemic density functional theory calculations were performed to elucidate diverse FMO-catalyzed oxidation reactions toward environmental pollutants, including denitrification (e.g., nitrophenol), N-oxidation (e.g., nicotine), desulfurization (e.g., fonofos), and dehalogenation (e.g., pentachlorophenol). Similar to the active center compound 0 of cytochrome P450, FMO mainly catalyzed reactions with the structure of the tricyclic isoalloxazine C-4a-hydroperoxide (FADHOOH). As will be shown, FMO-catalyzed pathways are more favorable with a concerted than stepwise mechanism; Deprotonation is necessary to initiate the oxidation reactions for phenolic substrates; The regioselectivity of nicotine by FMO prefers the N-oxidation other than N-demethylation pathway; Formation of the P-S-O triangle ring is the key step for desulfurization of fonofos by FMO. We envision that these fundamental mechanisms catalyzed by FMO with a computational method can be extended to other xenobiotics of similar structures, which may aid the high-throughput screening and provide theoretical predictions in the future.
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