PM2.5中丙二醛的检测、浓度特征及氧化损伤的研究

以和田市城区2014年采集的大气PM_(2.5)样品为实验对象,将0.1 g的PM_(2.5)样品膜与2-硫代巴比妥酸(0.2%)和三氯乙酸(20%)混合显色液反应,用可见光分光光度计测定反应产物的吸光度,通过正交实验来优化PM_(2.5)膜中丙二醛(MDA)的提取及测定条件,结果表明,在反应温度90℃、超声和加热时间40 min、显色剂用量为45 mL时,反应产物在532 nm处具有稳定的最大吸收峰。对和田市城区PM_(2.5)及MDA质量浓度的变化特征分析结果表明,和田市城区4个季节PM_(2.5)平均质量浓度由高到低顺序分别为春季(1 096.67±369.60)μg/m~3、夏季(1 016.16±708.00)μg/m~3、秋季(686.88±525.00)μg/m~3和冬季(214.54±94.70)μg/m~3。MDA平均质量浓度的变化范围为1.10～7.75 ng/m~3,其平均值最高为夏季(4.43±1.80)ng/m~3,最低为春季(1.42±0.60)ng/m~3,冬季与秋季相当,分别为(2.93±0.70)ng/m~3和(2.83±0.80)ng/m~3;最终,将PM_(2.5)膜中MDA的质量浓度与相应的TD_(30)(体外DNA氧化损伤达到30%的剂量)进行相关性分析得出,无论是全样还是水样的TD_(30)值均随MDA浓度的升高而呈降低的趋势。其中,全样与MDA质量浓度的相关性更为显著(r=-0.597,显著性P0.01)。     

环境湿度对PM2.5手工测量(重量法)的影响

为了解天平室环境湿度对PM_(2.5)手工称重的影响,利用滤膜自动称重系统,在45%、50%、55%3个环境相对湿度条件下对同一组滤膜进行称重。结果显示:45%、55%湿度条件下测量的大部分滤膜质量与50%基准湿度条件下滤膜质量绝对差值均超过0.04 mg,且随着滤膜质量即PM_(2.5)浓度的增加,绝对差值显著上升,难以满足手工称重规范中的要求。PM_(2.5)手工测量浓度在150μg/m~3以下时,3种湿度条件下测量结果的标准偏差保持在2μg/m~3范围之内,而PM_(2.5)手工测量浓度在150μg/m~3以上时,标准偏差超出2μg/m~3范围,且随着浓度升高,标准偏差显著增大,这会给PM_(2.5)的手工测量准确度带来较大影响,说明手工称量环境湿度±5%的允许变化范围并不适合PM_(2.5)平均浓度较高的国家和地区。     

衡阳城区冬季PM2.5中水溶性离子污染特征

为探究衡阳冬季PM_(2.5)和水溶性离子污染特征及其来源,于2019年1月在衡阳市城区采集大气PM_(2.5)样品,使用重量法和离子色谱法测得PM_(2.5)和水溶性离子组分质量浓度,并分析其浓度特征、酸碱度和来源等问题。结果表明:采样期间衡阳大气PM_(2.5)平均质量浓度为94.25μg/m~3,总水溶性离子质量浓度为52.94μg/m~3,占PM_(2.5)总质量浓度的56.43%;阴阳离子当量之比为1.12,PM_(2.5)呈酸性,其中SNA(SO_4~(2-)、NO_3~-和NH_4~+)占总水溶性离子质量浓度的95.06%。污染期间二次转化明显,SNA主要以(NH_4)_2SO_4和NH_4NO_3形式存在。源解析发现大气PM_(2.5)受化石燃料和生物质燃烧、垃圾焚烧、建筑扬尘、气态前体物二次转化、外来输送等多重因素影响,其中机动车尾气排放的NO_x在大气中二次转化形成的硝酸盐是衡阳重污染的最主要原因。     

盐城市秋冬季节PM2.5污染特征及来源分析

于2019年10月—2020年2月在盐城市开展大气PM_(2.5)离线监测,对PM_(2.5)的浓度变化、质量平衡、组分及来源进行了分析。结果表明,监测期间盐城市ρ(PM_(2.5))月均值为43.32～62.59μg/m~3,其中1月最高;监测期间ρ(PM_(2.5))平均值为54.25μg/m~3,质量重建后该值为52.38μg/m~3,与实测值的相关性达到0.98; PM_(2.5)占比最多的成分是硫酸盐、硝酸盐和铵盐(SNA); m(NO_3~-)/m(SO_4~(2-))的平均值为2.16,说明监测期间盐城市机动车相比固定源对NO_2和SO_2有更高的贡献;通过主成分因子分析,可知盐城市秋、冬季节PM_(2.5)主要来源于土壤和扬尘源、燃烧源以及二次无机源。     

采暖期大气颗粒物PM1.0和PM2.5中水溶性离子污染特征

为了解采暖期大气PM_(1.0)和PM_(2.5)中水溶性离子污染特征,采集哈尔滨市2014年11月至2015年3月采暖期PM_(1.0)和PM_(2.5)的样品,进而分析其中的水溶性离子(F-、Cl-、NO-3、SO2-4、Na+、NH+4、K+、Mg2+、Ca2+)的质量浓度。结果表明:PM_(1.0)和PM_(2.5)中的水溶性离子具有相同的变化趋势。采暖期间PM_(1.0)和PM_(2.5)中9种水溶性离子质量浓度总和分别为25.4~60.7μg/m~3和38.8~78.0μg/m~3。在PM_(1.0)和PM_(2.5)中NH+4、NO-3、SO2-4占比较高,而F-、Mg2+占比较低。PM_(1.0)和PM_(2.5)中9种水溶性离子质量浓度均为夜间大于白天。在PM_(1.0)和PM_(2.5)中,Mg2+和NH+4、F-和Cl-呈显著相关,说明它们来自相似的污染源,在PM_(1.0)中的K+和Ca2+显著相关,故它们受相似的污染源的影响。根据酸度与各离子的相关性,得出SO2-4和NH+4是控制大气颗粒物酸碱性的主要离子。另外,气象因素对PM_(1.0)和PM_(2.5)的浓度有影响。     

邢台市颗粒污染物变化特征和后向轨迹分析

为深入了解邢台市PM_(10)、PM_(2.5)浓度变化情况和气流后向轨迹,对邢台市2013—2016年环境大气颗粒污染物监测数据进行了分析,同时利用HYSPLIT模型计算出逐日72 h后向气流轨迹。结果表明:邢台市的PM_(10)和PM_(2.5)质量浓度在2013—2016年间呈逐年下降趋势,PM_(10)和PM_(2.5)质量浓度高值出现在冬季(296μg/m~3和192μg/m~3),最低值出现在夏季(140μg/m~3和80μg/m~3),PM_(10)和PM_(2.5)质量浓度在日变化上均呈"双峰双谷"型分布;后向轨迹的季节聚类分析表明,春季大气颗粒物污染以粒径2.5～10μm的颗粒污染物为主,夏季、秋季和冬季的大气颗粒物污染以PM_(2.5)为主;逐日聚类分析表明,在路径为西北偏西向的、途经多个沙源地的气流影响下,邢台市的PM_(10)和PM_(2.5)质量浓度处于一个相对高值;来源于偏南向的气流由于化合反应,污染物积聚导致PM_(10)、PM_(2.5)质量浓度也处于相对高值;在来源于西北向和偏北向的、水汽含量相对较低的气流影响下,邢台市的PM_(10)、PM_(2.5)质量浓度出现一个明显的下降。     

北京昌平某地冬季大气PM2.5元素污染特征分析

以北京昌平区某地大气PM_(2.5)和重金属污染状况为研究对象,应用射线法与XRF技术相结合的分析技术,对PM_(2.5)浓度和其重金属组分浓度进行同步监测,以重金属元素为污染物示踪因子进行污染特征分析。结果表明,监测期间该区域PM_(2.5)平均质量浓度达92μg/m~3,Ca、Fe、K元素含量较高。通过主成分分析该区域PM_(2.5)元素影响因素主要为工业和生活燃料燃烧、冶金工业废气、扬尘3类,贡献比分别为52.42%、26.82%、13.10%。     

武汉市春季大气PM2.5中水溶性离子特征

运用大气PM_(2.5)水溶性组分及其气态前体物在线监测系统(GAC-IC)于2017年3月5—12日对武汉市大气PM_(2.5)中水溶性组分进行了在线监测,分析了PM_(2.5)中主要水溶性离子的化学特征和作用机制。结果表明:实验期间武汉市大气PM_(2.5)中水溶性组分与气态前体物间存在明显的二次转化过程,二次反应是PM_(2.5)的重要来源。监测期间,PM_(2.5)中NO_3~-、SO_4~(2-)和NH_4~+的平均质量浓度分别为24.3、16.9、15.0μg/m~3,是PM_(2.5)中重要的水溶性无机离子,占PM_(2.5)质量浓度的40%~70%。硫氧化率(SOR)和氮氧化率(NOR)平均值分别为0.52和0.27,表现出较为明显的二次污染特征。通过相关性分析发现:监测点位周边大气PM_(2.5)中NH_4~+与NO_3~-、SO_4~(2-)有良好的相关性,且表现为富氨状态,大气中铵能较好地中和SO_4~(2-)和NO_3~-。     

齐齐哈尔市PM2.5与PM10污染趋势及相关性分析

对2014—2016年齐齐哈尔市PM_(2.5)与PM_(10)质量浓度的时间变化特征进行简要分析,并探究PM_(2.5)/PM_(10)以及PM_(2.5)与PM_(10)的相关性。结果表明:2014—2016年齐齐哈尔的PM_(2.5)与PM_(10)的年均质量浓度分别为36.7、62.9μg/m~3,且呈逐渐下降趋势;冬季的PM_(2.5)与PM_(10)浓度最高,秋季次之,春季与夏季相对较低;2014—2016年PM_(2.5)与PM_(10)质量浓度月变化趋势基本相同,整体呈现2—6月逐渐下降,9—11月逐渐上升的规律;PM_(2.5)与PM_(10)质量浓度的日变化均呈双峰现象;对PM_(2.5)与PM_(10)进行线性拟合,相关系数为0.896 3。同时,残差分析也说明两者拟合情况良好,四季相关系数为r_(秋季)(0.982 2)r_(冬季)(0.964 4)r_(夏季)(0.943 9)r_(春季)(0.829 6);2014—2016年PM_(2.5)/PM_(10)平均值为55.27%,大气颗粒物PM_(2.5)的贡献率高达一半以上。     

宜兴市细颗粒物化学特征和来源解析

通过在宜兴市3个监测站点对细颗粒物(PM_(2.5))开展不同季节采样,对样品做化学分析,结合化学质量平衡(CMB)模型解析PM_(2.5)来源贡献。结果表明,宜兴市PM_(2.5)年均质量浓度为37.5μg/m~3,冬季质量浓度最高,为53.1μg/m~3。PM_(2.5)主要化学成分为SO_4~(2-)、NO_3~-、OC、EC、NH_4~+、Cl~-、Ca、Na、Al。PM_(2.5)的主要排放源贡献为二次硫酸盐(21.0%)、二次有机气溶胶(14.9%)、二次硝酸盐(14.1%)和燃煤电厂(8.0%)。利用本地排放源清单进行二次来源解析,得到全年主要排放源贡献为工业(33.1%)、燃煤(23.1%)、移动源(17.6%)、扬尘(9.3%)和其他来源(16.9%)。减轻颗粒物污染,重点是控制工业生产、燃煤及机动车中的排放。     

兰州市冬季和春季PM2.5金属元素浓度水平与分布

为了解兰州市大气PM2.5中金属元素的污染水平和分布,于2013年冬季和春季在兰州市区4个在线监测点进行PM2.5样品采集,利用ICP-MS分析金属元素浓度。结果表明,Pb、B元素含量高于200 ng/m3,V、Fe元素含量在100~200 ng/m3,其余元素含量低于100 ng/m3,其中Pb含量最高,平均含量达到373.8 ng/m3.各监测点元素含量在冬季和春季各有不同,整体上是冬季高于春季。金属元素在兰州市区的空间分布与兰州市工业排放和气象因素有关,工业排放为主导因素。     

太原市冬、夏季醛酮化合物污染特征及来源分析

针对太原市空气臭氧污染较为严重的问题,开展臭氧主要前体物醛酮化合物质量浓度及其变化规律研究.利用2,4-二硝基苯肼固相吸附/高效液相色谱方法,通过对太原市2019年冬季和夏季大气的醛酮化合物进行分析,发现太原市冬季总醛酮化合物的平均质量浓度为13μg/m3,低于夏季的27μg/m3.其中甲醛、乙醛和丙酮质量浓度最高,且...     

Pesticides and Nitrate in Groundwater and Rainwater in the Province of Limburg in The Netherlands

The purpose of this study was to investigate the occurrence ofhigh levels of pesticides in groundwater and rainwater in TheProvince of Limburg in The Netherlands. In groundwater samplesin particular the presence of triazines – atrazine, simazine and propazine – was observed; besides these pesticides, dieldrin has also been observed. Atrazine and simazine were found to exceed the groundwater standard of 100 ng L^-1. In the rainwater samples, the presence of 13 of 23 different analyzed pesticides was observed. A number of pesticides werefound in high concentrations; e.g. atrazine (>200 ng L^-1). Two pesticides detected in rainwater (+-HCH and atrazine) were found to exceed the groundwater standard. Seven pesticides in rainwater were found to exceed the target value and three pesticides the maximum tolerable risk value (DDT, heptachlor and heptachlorepoxide A), which are used as ecotoxicological standards in The Netherlands.Nitrate in 15 of 16 analyzed natural springs was found toexceed the guideline value for nitrate in drinking waterof 50 mg L^-1, up to levels of about 200 mg L^-1. Nitrate concentrations in rainwater samples were observed up to 4.5 mg L^-1. A risk analysis of exposure to high pesticide levels in groundwater or rainwater has been performed using the model HESP. For atrazine levels due todeposition of rainwater in two different locations, exceedance of the T.D.I. level of 0.5 g kg^-1 day^-1 based on WHO criteria was observed for children using both an urban and a rural scenario and use of groundwater as drinking water.     

Long-term changes in acidity and DOC in throughfall and soil water in Finnish forests

The main objective of this study was to examine if any detectable trends in dissolved organic carbon (DOC), sulphate (SO₄-S) concentrations and acid neutralizing capacity (ANC) in throughfall (TF) and soil water (SW) could be found during 1990–2010 and to relate them to recent changes in decreased acid deposition. The study was conducted in seven boreal coniferous forest sites: four of which are managed and three unmanaged forests sites. Generally, temporal trend showed a significant decrease in SO₄-S concentrations in bulk precipitation (BP), TF and SW. At some of the sites, there was an increasing tendency in BP and TF in the DOC concentrations. This feature coincides with decreasing SO₄-S concentration, indicating that SO₄-S may be an important driver of DOC release from the canopy. However, a slightly increased temperature, larger senescing needle mass and consequently increased decaying activity in the canopy may partly explain the increasing trend in DOC. In SW, no consistent DOC trend was seen. At some sites, the decreased base cation concentrations mostly account for the decrease in the ANC values in SW and TF.     

Organochlorine insecticide residues in drinking and ground water in and around Delhi

A multiresidue method was developed for the estimation of 15organochlorine pesticides in water. 50 samples of drinking watersupplied by the Municipal Corporation to the residential areasof Delhi and 20 ground water samples from nearby villages usedfor irrigation were monitored for the presence of organochlorineinsecticides by the method developed. Although, organochlorinepesticides were detected in the ground water and irrigationwater samples, the levels of pesticides were below the MaximumContaminant Level as prescribed by WHO. No organochlorineinsecticides were detected in any of the drinking water samples.     

Pesticides and Trace Metals Residue in Grape and Home made Wine in Jordan

Sixty home made wine and sixty-four grape samples were collectedfrom five territories in Jordan, where grapes and wine aremostly producted. The collected samples were analyzed for themost used organochlorine pesticides (OCP) and organophosphorouspesticides (OPP) in Jordan, as well as for four heavy metals(Ni, Cu, Zn and Pb). The results showed that OCPs residues weredetected in 73% of the wine samples but no OPPs residue weredetected which is due to generally shorter half life of thelater pesticide. Grapes showed higher incident of contaminationthan wine, however, OCPs and OPPs with both short and longhalf-lives were detected. The OPPs were detected in only8.3% of the analyzed grape samples. Heavy metals showed higher valuesin grapes than in the wine samples and it was attributed toremoval of solids during wine preparation processes or throughcontamination of wine during storage. Most of the samples werebelow toxic limit.     

宽甸土壤及部分农作物中硼的分布及污染分析

用ICP-MS测定了辽宁宽甸23个土壤样品中的硼。背景地区和污染地区的土壤硼含量分别在 39.2～82.4mg/kg和133～1195mg/kg之间。其中硼矿开采区的土壤硼含量高达1195mg/kg。还用同样的方法分析了背景地区和污染地区几种农作物中硼的含量,结果表明,背景地区的大豆、土豆、玉米和豆角的硼含量(干基)分别为:37.4～47.9、5.8～6.3、24.4～25.5和1.24～2.74mg/kg,而污染地区相应农作物的硼含量分别为:34.0、12.0～12.8、40.7和2.48～2.64mg/kg。     

郑州市土壤与绿色植物中汞的分布特征

汞污染具有生物积累性,因而得到社会广泛关注。研究监测和评估了郑州市城区土壤和绿色植物叶片中汞浓度、分布、污染水平等。研究发现郑州市主城区土壤总汞浓度为0. 150～0. 958 mg/kg,平均浓度为0. 448 mg/kg;郑州市主城区绿色植物叶片总汞浓度为0. 017～0. 249 mg/kg,平均浓度为0. 107 mg/kg;土壤和叶片中汞浓度按功能区排序为交通枢纽区工业区商业区行政区高教区住宅区。采用地累积指数法对郑州市80个土壤样品的汞污染水平进行评估,结果显示60%受到轻度污染,35%受到偏中度污染,5%受到中度污染。研究较为全面地分析了土壤汞污染的现状及浓度,为郑州市土壤汞污染防治提供参考。     

郑州大气及颗粒物中多环芳烃的分布特征与来源解析

对2012年郑州市大气中气态和颗粒态多环芳烃(PAHs)的分布特征与来源进行了分析。结果表明,ρ(∑PAHs)(包括气相与颗粒相)为23.27~194.61 ng/m3,气相中∑PAHs高于颗粒相,四环以下的PAHs大都存在于气态中;在夏、春2季,较小分子质量(≤178)的PAHs占比较高,冬季,较大分子质量(≥252)的PAHs占比明显较高;各功能区ρ(PAHs)排序为工业区交通密集区医疗、文化、行政混合区。郑州大气和颗粒物中PAHs可能主要来自煤和液体燃料(汽油柴油)的燃烧。     

大同市地表水及工业废水中氯苯和酚类化合物的监测

对流经大同市的主要河流和重点工业污染源所排放废水中的氯苯和酚类化合物做了分析测定.对酚类化合物的测定方法进行了改进.研究表明,大同市污染源对御河氯苯类污染物贡献较小,焦化厂酚类化合物排放量较高.