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1.
类腐殖质(humic-like substances, HULIS)是水溶性有机碳(WSOC)中具有吸光特性的重要组分,对空气质量、气候变化和人体健康均有重要影响.尽管目前对HULIS的研究很多,但不同方法分离机理不同,对于HULIS的分离与测定仍然缺乏统一的标准,针对HULIS分离方法的研究很少.固相萃取法(solid phase extraction, SPE)因其操作简单、分离效果较好而被广泛应用,但对于低浓度样品仍存在检出限较高、回收率较低的问题,且很少有人关注提纯过程中流程空白所包含的含碳组分及其吸光能力.本研究通过调整活化溶液(0.01 mol·L-1 HCl溶液+甲醇+2%NH3H2O/MeOH)与洗脱溶液(2%NH3H2O/MeOH)用量的比例对提纯方法进行优化.结果表明,应用优化后的方法对流程空白进行测量时,检出限(MDL)降低到0.035 mg·L-1以下,精密度RSD <5.41%(n=20),标准品回收率达到95%,在保证回收率的情况下减少了流程空白,提高了样品的精密度,使测定浓度较低的HULIS含量成为可能.为了探究生物质燃烧期间含碳组分的光学特性和来源特征,本研究对2017年10月6日至11月9日南京北郊秋季大气气溶胶样品进行采集.采样期间PM2.5的浓度为(87.9±43.7)μg·m-3,WSOC和类腐殖质碳(HULIS-C)的浓度分别为(4.2±2.3)μg·m-3和(3.6±2.0)μg·m-3,HULIS-C占WSOC的比例为47.3%,是WSOC中的重要组成部分.本研究还对HULIS在330—400 nm波段的吸光进行测定,使用Angstrom指数(absorption angstrom exponent,AAE)进行表征,得到采样期间AAE的值为2—7,说明HULIS污染主要来自二次转化.后向轨迹结果表明,重污染期间污染物来源为本地生物质燃烧和区域或者长距离气团的输送.  相似文献   

2.
大气颗粒物中类腐殖酸的研究进展   总被引:4,自引:0,他引:4  
类腐殖酸(HULIS)是一类广泛存在于云、雾、雨水和大气气溶胶颗粒中的大分子有机物.HULIS既可通过吸收和散射太阳辐射直接影响大气热平衡,又能参与云凝结核的形成间接影响全球气候,加之其重要的环境和健康效应,近年来引起科学界的广泛关注.本文综述了大气颗粒物中类腐殖酸的研究成果,主要包括HULIS的分离、提取和分析方法,HULIS的主要理化性质、浓度和季节变化,以及HULIS的来源和国内外研究现状,并对该领域的研究前景进行了分析和展望.  相似文献   

3.
为探讨典型稀土矿城市不同季节大气可吸入颗粒物(inhalable particulate matter,PM10)中稀土元素污染特征及其细胞毒性响应,将前期采集于包头市的PM10颗粒物进行提取,检测PM10中的稀土元素(rare earth elements,REEs)含量,并将人肺上皮细胞(A549)暴露于不同浓度水平(25,50,100μg·m L-1)的PM10样品和标准颗粒物1649b(standard reference material,SRM1649b)暴露液,用WST-1法测定暴露24 h后的细胞活性,用2’7’二氯荧光素二醋酸盐(2’7’-dichlorofluorescein diacetate,DCFH-DA)荧光探针法和彗星实验分别测定暴露3 h后的细胞内活性氧(reactive oxygen species,ROS)产生水平和DNA双链损伤程度。结果表明,包头春、夏季大气PM10和SRM1649b均引起A549细胞活性下降,并诱导细胞内ROS生成量增加,造成显著的细胞内DNA损伤,含REEs的大气颗粒物毒性显著高于标准颗粒物。与春季相比,包头夏季PM10对细胞活性的抑制程度更高,造成更多的DNA双链损伤,从而表现出更强的细胞毒性和遗传毒性。包头PM10呈现明显的轻稀土元素(light rare earth elements,LREEs)富集,铈(Ce)、钷(Pm)、镧(La)和钕(Nd)含量占稀土总量的50%以上。LREEs均与细胞活性和细胞内ROS产生水平呈负相关性,包头春季和夏季PM10中稀土元素含量的差异是导致包头PM10细胞毒性效应不同于标准颗粒物且具有季节性差异的原因之一。  相似文献   

4.
了解不同耕作与培肥模式对麦田土壤的影响,对提升麦田土壤地力及促进小麦的持续高产具有重要的意义。试验于2011-2012年在许昌县陈曹乡史庄村小麦试验田进行,以周麦22为试验材料,分别于孕穗期、开花期和成熟期取土测定土壤微生物与腐殖质含量。借助方差分析和相关分析等经典统计方法研究了不同耕作模式(浅耕15~20 cm;深耕35~40 cm)和培肥模式(单施化肥;化肥增施有机肥)对麦田土壤腐殖质与微生物的影响。试验结果表明:深耕增施有机肥能够显著提高小麦生育后期0~5和5~20 cm耕层土壤富里酸含量(p〈0.01)。增施有机肥有利于小麦生育后期各耕层土壤胡敏酸含量的积累(p〈0.05),其中20~40 cm耕层土壤增幅最为明显,成熟期深耕增施有机肥与浅耕增施有机肥和开花期相比增幅分别达253.85%与300.00%;深耕增施有机肥能够显著提高小麦孕穗期与成熟期5~20 cm耕层土壤细菌数量(p〈0.01),成熟期浅耕增施有机肥与深耕增施有机肥处理细菌数量和开花期相比增幅分别达690.38%和508.75%,其中深耕增施有机肥处理与其它三个处理相比细菌数量最多且差异极显著(p〈0.01)。增施有机肥能够显著提高小麦成熟期0~5与20~40 cm耕层土壤真菌数量(p〈0.01),深耕增施有机肥能够显著提高小麦孕穗期5~20 cm耕层土壤真菌数量(p〈0.01)。深耕增施有机肥能够显著提高小麦生育后期20~40 cm耕层土壤放线菌数量(p〈0.05)。相关分析表明,在本研究培肥和耕作模式下麦田土壤腐殖质组分的含量与微生物区系的数量呈正相关关系。  相似文献   

5.
PM2.5引起的健康危害日益受到广泛关注,但其确切的损伤机理仍不完全清楚,目前也缺乏有效拮抗PM2.5损伤的天然活性物质。因此本文对北京市PM2.5造成CHO细胞的损伤作用及天然物质的拮抗作用进行研究,结果可为PM2.5污染治理和疾病的预防提供科学依据。通过CCK-8法测定细胞存活率;通过流式细胞仪测定细胞凋亡;用荧光探针DCFH-DA法测定ROS;提取细胞内总蛋白并测定其中SOD含量;以及通过Western Blot法分别测定了p-akt/akt、p65及Bad的相对表达量。结果显示:(1)10~40μg·m L-1的PM2.5可明显降低CHO细胞存活率,并呈现极显著的剂量-效应关系(r=-0.964,P0.01);15μg·m L-1PM2.5可以显著增加细胞凋亡、引起细胞内ROS增加、SOD含量下降;p-akt/akt、p65表达量增加说明Akt通路与NF-κB通路均被激活。(2)20μmol·L-1阿魏酸、50μmol·L-1绿原酸和10μmol·L-1荭草素预处理可拮抗PM2.5引起的细胞存活率下降以及细胞凋亡率增加,同时降低细胞内ROS并增加SOD含量,下调p-akt/akt、p65及Bad的相对表达量。其中20μmol·L-1阿魏酸的保护作用最佳。结果说明,PM2.5引起的CHO细胞损伤与细胞凋亡与Akt和NF-κB通路的激活有关;三种天然活性物质具有拮抗PM2.5造成的细胞损伤的能力,其保护机理是通过其降低PM2.5引起的细胞内氧化应激反应,进而降低被PM2.5激活的Akt通路与NF-κB通路和下调Bad蛋白表达量来实现的。  相似文献   

6.
采集大连城区大气中可吸入性细颗粒物(PM_(2.5)),研究其对肺癌A549细胞迁移、黏附和侵袭力的影响,利用明胶酶谱法检测细胞分泌的基质金属蛋白酶活性,利用Western blot法测定A549细胞中转移相关蛋白的表达。结果表明,在无明显细胞毒性浓度下,PM_(2.5)可增加A549细胞的迁移速率;细胞与细胞外基质的黏附率增加;细胞侵袭实验结果表明PM_(2.5)可增加A549细胞穿透基底膜的能力;用明胶酶谱法检测发现PM_(2.5)可使A549细胞分泌的基质金属蛋白酶-2(MMP-2)和基质金属蛋白酶-9(MMP-9)活性增强。转移相关蛋白——细胞钙粘蛋白-N(N-cadherin)的表达量升高,而钙粘蛋白-E(E-cadherin)的表达量下降,实验结果表明,PM_(2.5)可增强A549细胞的侵袭性,大气中的可吸入性颗粒可能导致肺癌转移发生率增加。  相似文献   

7.
大气颗粒物对肺免疫系统有潜在毒性作用,打破免疫系统平衡,大气颗粒物成分中危害首当其冲的是大气细颗粒物(PM_(2.5)),为研究大气细颗粒物引起的机体T淋巴细胞中Th1/Th2免疫失衡方向。本研究通过免疫组化实验方法检测暴露后小鼠肺组织中T淋巴细胞的表达,进一步采用流式细胞术检测大气细颗粒物气管滴注后小鼠肺脏淋巴细胞中Th1/Th2比例。暴露组小鼠肺组织免疫组化研究结果提示浸润细胞区有大量的CD4~+T细胞,中高剂量暴露组小鼠肺组织中淋巴细胞亚群Th1/Th2比例向Th1偏移。大气细颗粒物影响免疫失衡,使T淋巴细胞向Th1漂移。  相似文献   

8.
宣威煤燃烧排放产物与其所导致的肺癌高发率一直是国际学术界关注的热点,但煤燃烧排放颗粒物中的关键致毒组分还不清楚。以肺癌高发区产出的晚二叠世C1煤燃烧排放不同粒径颗粒物为研究对象,分析其中主要有害有机污染物多环芳烃(PAHs)的分布特征及其健康风险。结果表明宣威煤燃烧排放的颗粒物中16种PAHs的总质量浓度为77 359.21 ng·m-3,其中含量最高的是苯并(g,h,i)苝,其他主要的PAHs依此为:屈、苯并(b)荧蒽、苯并(a)蒽、荧蒽、二苯并(a,h)蒽、菲、苯并(k)荧蒽、茚并(1,2,3-cd)芘;强致癌化合物苯并a芘(Ba P)总浓度亦可达到10 060.13 ng·m-3;这些有害有机物主要分布在细颗粒物中;不同粒径颗粒物的毒性当量存在明显差异,细颗粒的毒性当量占可吸入颗粒物中PAHs总毒性当量的87.4%,远高于粗颗粒(12%)和超细颗粒物(0.4%)的毒性当量。  相似文献   

9.
10.
选取我国有代表性的16种土壤,通过基质诱导硝化(SIN)的方法,研究了淋洗与未淋洗处理后,土壤中外源Zn对不同土壤潜在硝化速率(PNR)的影响。结果表明:在未淋洗处理土壤中Zn毒性的EC50(使PNR降低至对照一半土壤中Zn的浓度)值的范围为197~1874mg·kg-1,相差近9.51倍;总体而言,土壤pH、有机碳及粘粒含量的提高可以降低土壤中Zn的毒性。偏相关分析结果表明,影响土壤中Zn对潜在硝化速率抑制作用的主要因子依次为土壤pH、有机碳含量及粘粒含量;淋洗处理明显提高了土壤中外源Zn的毒性阈值浓度,在不同土壤中,淋洗因子(定义为淋洗后的土壤Zn毒性的EC50与非淋洗EC50的比值)范围为1.16~1.43;基于土壤主要性质的多元回归预测模型结果表明,利用土壤性状(pH、有机碳和粘粒含量)可以很好地预测土壤中Zn对硝化速率抑制的毒性阈值。  相似文献   

11.
城市空气悬浮颗粒物的理化性质及其健康效应   总被引:6,自引:0,他引:6  
郭二果  王成  彭镇华  房城 《生态环境》2008,17(2):851-857
城市空气悬浮颗粒物的理化性质是其他相关研究的理论基础,目前的研究主要集中在分析空气颗粒物的成分组成、来源解析上.空气悬浮颗粒物主要由金属元素、有机化学成分和无机盐类等组成,城市交通、工业等各种源的排放是其主要来源,按照粒径大小不同一般可将其分为总悬浮颗粒物(TSP)、可吸入颗粒物(PM10)、细颗粒物(PM2.5)等.空气悬浮颗粒物达到一定浓度后,会对环境和人体产生一定的危害,而且颗粒物粒径大小不同,来源和成分组成就有别,其产生的危害程度也不一样.文章从粒径大小、来源、成份以及三者间的相互关系等几个方面详细阐述了城市空气悬浮颗粒物的理化性质,并从其对人体、其他动植物和环境等方面造成的影响综述了空气颗粒物的健康效应及影响因素,最后又提出了今后的研究方向和发展途径.  相似文献   

12.
Environmental Chemistry Letters - Air pollution is a major issue for human health with more than 7 million premature deaths per year due to indoor and outdoor air pollution. Exposure to particulate...  相似文献   

13.
A simple and rapid method has been optimised to determine glyoxal and methylglyoxal in atmospheric particulate matter by extraction and derivatisation with 2,4-dinitrophenylhydrazine solutions. Minimal sample preparation was required by mixing a portion of filter charged with atmospheric particulate matter with 5?mL of a saturated solution of 2,4-dinitrophenylhydrazine (1.6?g?L?1) in acetonitrile and acidified by H2SO4 (50?µL?L?1). Chromatographic analyses were carried out 1?h after derivatisation solution was mixed. Finally, the proposed method was applied to quantify these dicarbonyls in atmospheric particulate matter samples, which were obtained as part of a large field study to characterise atmospheric aerosol from a rural area of Madrid. Glyoxal concentrations averaged 0.24?ng?m?3, whereas mean values of methyl glyoxal were around 0.95?ng?m?3. Methyl glyoxal levels showed a clear relationship with the particulate matter levels, whereas glyoxal data did not show such a correlation. This could indicate that both dicarbonyls come from different sources.  相似文献   

14.
Polycyclic aromatic hydrocarbons (PAHs) and nitro polycyclic aromatic hydrocarbons (N-PAHs) are chemical species of proven mutant and carcinogenic activity. In this study, the concentrations of seven different N-PAHs [2-nitronaphthalene (2N-NAP), 2-nitroflourene (2N-FLU), 2-nitroflouranthene (2N-FLA), 3-nitroflouranthene (3N-FLA), 1-nitropyrene (1N-PYR) and 2-nitropyrene (2N-PYR)] were determined in two fractions of atmospheric particulate matter from the atmosphere of Athens: coarse (2.4 μm?10 μm ) and fine (<2.4 μm ). 3N-FLA was not detected, whereas 1N-PYR, mostly originating from emissions from burning fuel, showed the maximum observed concentrations for both fractions and for the whole experimental period (especially during winter). In addition, 2N-FLA, a secondary nitro-PAH produced by photochemical reactions, showed relatively high values. Analysis of statistical data for N-PAH concentrations, using clustering technique, showed that: (1) 1N-NAP, 2N-FLU and 1N-PYR are mainly produced by direct burning; and (2) photochemical reactions are the dominant sources of 2N-NAP, 2N-PYR and 2N-FLA.  相似文献   

15.
Particulate matter (PM) is both a major driver of climate change and a source of toxicity for health. In the upper atmosphere, particulate matter modifies the earth radiation budget, cloud formation and acts as a reaction center for air pollutants. In the lower atmosphere, particulate matter changes atmospheric visibility and alters biogeochemical cycles and meteorology. Most critical effects are observed in ambient air, where particulate matter degrades human health. Here we review the sources, spatial and temporal variability, and toxicity of PM10, the particulate matter having particle sizes 10 micrometers or less in diameter, in world regions. For that we analyzed information from the world wide web and databases from government organizations after the year 2000. Findings show that PM10 is a major risk in both developed and developing countries. This risk is more severe in Asian countries compared to Europe and USA, where decreasing trends are recorded during the last two decades. Meteorological factors modify particulate matter variations at local and regional levels. PM2.5/PM10 ratio provides information of particulate matter sources under different environment conditions. Crustal matter, road traffic and combustion of fuels are major sources of particulate matter pollution. Health studies indicate that long-term exposure to particulate matter has multiple health effects in people from all age groups. Identification of possible sources and their control with regular epidemiological monitoring could decrease the impact of particulate matter pollution.  相似文献   

16.
为研究日喀则不同粒径大气颗粒物中水溶性无机离子的组成特征,利用Andersen分级撞击式采样器在夏、冬季进行大气颗粒物分级采样,采用离子色谱测定NH+4、Ca2+、K+、Mg2+、Na+、SO2-4、NO-3和Cl-等8种离子浓度.结果表明,夏、冬季总离子浓度分别为9648±3030、4925±1138 ng·m-3.夏季离子浓度高低顺序为Cl-﹥Ca2+﹥NH+4﹥Na+﹥SO2-4﹥NO-3﹥K+﹥Mg2+,Cl-、Ca2+、NH+4和Na+占总离子浓度的比重为74.9%;冬季水溶性无机离子浓度高低顺序为Cl-﹥SO2-4﹥NH+4﹥NO-3﹥Ca2+﹥Na+﹥K+﹥Mg2+,Cl-、SO2-4、NH+4和NO-3占总离子浓度的比重为88.0%.夏、冬季大气颗粒物中所有水溶性无机离子的粒径分布均成双峰型.夏季,大气颗粒物中SO2-4与Mg2+(r=0.951)、Ca2+(r=0.947),NO-3与Mg2+(r=0.904)、Ca2+(r=0.843),在0.01水平(双侧)上均显著相关;冬季,细粒子中K+与Cl-(r=0.740)、SO2-4(r=0.929)及NO-3(r=0.920),在0.01水平(双侧)上显著相关.  相似文献   

17.
Zheng  Sheng  Wu  Xue  Lichtfouse  Eric  Wang  Jing 《Environmental Chemistry Letters》2022,20(5):2735-2743
Environmental Chemistry Letters - Air pollution, measured by the concentration of airborne particulate matter with diameter below 2.5&nbsp;μm (PM2.5), is known to cause globally adverse...  相似文献   

18.
The development of industry in Beijing, the capital of China, particularly in last decades, has caused severe environmental pollution including particulate matter (PM), dust–haze, and photochemical smog, which has already caused considerable harm to local ecological environment. Thus, in this study, air particle samples were continuously collected in August and December, 2014. And elements (Si, Al, V, Cr, Mn, Fe, Ni, Cu, Zn, Mo, Cd, Ba, Pb and Ti) and ions (\({\text{NO}}_{3}^{-}\), \({\text{SO}}_{4}^{2-}\), F?, Cl?, Na+, K+, Mg2+, Ca2+ and \({\text{NH}}_{4}^{+}\)) were analyzed by inductively coupled plasma mass spectrometer and ion chromatography. According to seasonal changes, discuss the various pollution situations in order to find possible particulate matter sources and then propose appropriate control strategies to local government. The results indicated serious PM and metallic pollution in some sampling days, especially in December. Chemical Mass Balance model revealed central heating activities, road dust and vehicles contribute as main sources, account for 5.84–32.05 % differently to the summer and winter air pollution in 2014.  相似文献   

19.
天水市大气颗粒物输送通道及污染源区研究   总被引:1,自引:0,他引:1  
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20.
Investigations on the fluctuation in PM10 air pollution in Volos, a medium-sized industrialized port city in the Mediterranean, are presented for the 5-year period between 2009 and 2014. The levels detected have been examined in relation to legislatively set limits, sampling year, and day of the week. A PM10 spring sampling campaign has been performed in 2014 and metals and other elements in the PM10 mass have been quantified. Source origin has been attempted for the latter sampling campaign and human health risk has been assessed. Results show compliance with the mean annual value of 40 μg m?3 of 2008/50/EC for the city; however, exceedances of the daily quality standard of 50 μg m?3 were frequently recorded. Shifts in PM10 concentrations and in contributing sources have been recorded; nevertheless, longer duration data series are needed for safe deductions. Element measurements have enabled source identification for early summer of 2014, with Earth's crust minerals and anthropogenic sources being the main factors. Cumulative non-carcinogenic risk may exceed the threshold value of 1. Possible involvement of sea salt aerosol and desert dust long-range transport has also been assessed. These results may furnish databases on PM pollution of Greek cities as well as other Mediterranean urban centers with similar characteristics.  相似文献   

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