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快速的经济和工业发展消耗了大量能源,世界主要城市空气质量下降,大量污染物排放至大气中[1]。其中,重金属会在大气颗粒物形成的过程中吸附在颗粒物的表面[2],随大气干、湿沉降降落至地面,进入物质循环系统,对生态环境和人体健康产生较大危害。
雪是大气颗粒物沉降的一种重要媒介,且提供环境改变情况的重要信息[3]。降雪对环境空气中的颗粒污染物有较强的富集作用,这种对污染物的消除能力相比降雨更强,所以降雪中污染物的特征能够反映当地大气污染基本状况。而积雪是一种开放体系,会受到周边环境的影响而受到二次污染[4],积雪作为受周边环境影响的受体,可能在污染组分的分布、来源等方面相对降雪有所差异,能够更客观地反映周边环境对雪水的影响。这些污染物会随着雪的融化而迁移到其他系统中,如水体、土壤等,并造成污染[5]。针对降雪、积雪化学组分的研究对揭示区域大气污染和评价其对水体造成污染的潜在风险有重要的意义。
国际上对于大气沉降的研究起始较早,对于干、湿沉降中重金属元素的研究主要选取湖泊、海岸、重金属矿区、远郊山区以及农田作为研究区域[6-11]。我国对大气沉降中重金属的研究主要集中于沉降通量[12]、时空分布[13]和来源解析[14]等。本课题组开展过关于乌鲁木齐及周边降雪、积雪污染组分和大气颗粒物重金属的研究[15-16],建立了乌鲁木齐市降雪、积雪监测采样点体系,并初步得出大气颗粒物重金属组分的分布情况,但未对降雪、积雪中重金属的分布情况及来源进行研究,本研究在本课题组研究的基础上在乌鲁木齐市不同功能区设置采样点对降雪、积雪中重金属的时空分布情况进行研究,并解析其来源,对本课题组在不同环境介质中大气重金属污染研究不足进行补充。
乌鲁木齐市作为自治区首府,是自治区政治、经济、文化中心,近几年快速的发展引发了一系列环境问题。乌鲁木齐冬季天气静稳,三面环山的特殊地形条件使逆温层较厚,大气混合层高度较低,种种不良的条件都不利于污染物的稀释扩散。虽近年因施行“煤改气”措施使燃煤污染源有所减少,但以煤炭、钢铁、陶瓷、化工、建材工业为主的工业经济体系和迅速增长的机动车保有量使大气环境污染形势依然严峻。同时,乌鲁木齐市是全国30个缺水城市之一,人均淡水资源拥有量低于公认极度缺水限值,地表水供给主要以冰雪供给融水为主。降雪、积雪中的重金属会污染地表水源,所以开展对于乌鲁木齐市降雪积雪重金属的研究对于分析干旱区水资源可利用性有重要意义。本研究于2017年1月、2月对乌鲁木齐市的降雪、积雪进行采集,使用原子吸收分光光度法和原子荧光光谱法分析其中的重金属组分,为判断乌鲁木齐市冬季大气重金属污染情况,分析乌鲁木齐市雪水资源的可利用性提供数据支撑。
降雪和积雪中重金属的污染状况与来源解析
——以乌鲁木齐市2017年初数据为例Pollution Status and Source Apportionment of Heavy Metals in Snowfall and Snow Cover——A Case Study from Urumqi During Early 2017
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摘要: 为了解乌鲁木齐市降雪、积雪中重金属的污染现状及来源,采集乌鲁木齐2017年1~2月期间不同功能区降雪和积雪样品,测定样品中的8种重金属元素,利用相关性分析、主成分分析和后向轨迹模型探究重金属的来源。结果显示:降雪、积雪中ρ(Fe)的平均值最高,分别为229.63、259.31 μg/L,ρ(Cd)的平均值最低,分别为3.28、9.33 μg/L,对比地表水环境质量标准,降雪、积雪中各重金属均存在一定超标情况;各功能区降雪中重金属浓度大小顺序为:交通区>工业区>商业区>生活区(建筑活动)>背景区,积雪中重金属浓度大小顺序为:生活区(建筑活动)>工业区>交通区>商业区>背景区。除Fe外积雪中重金属浓度大小顺序为:工业区>交通区>商业区>生活区>背景区。相关性与主成分分析解析出降雪中重金属的来源是交通排放、燃煤和金属冶炼,积雪中重金属的来源是燃煤、交通和金属冶炼以及钢铁生产。后向轨迹分析得出两类气团源区无典型污染源,乌鲁木齐市降雪、积雪中污染物来源于本地源排放。Abstract: In order to understand the pollution status and sources of heavy metals in snowfall and snow cover of Urumqi city, samples from snowfall and snow cover were collected in different functional areas from January to February in 2017. The concentrations of 8 types of heavy metals in snow were determined, and the sources of heavy metals were explored using correlation analysis, principal component analysis and Backward Trajectory Model. The results showed that the average value of ρ(Fe) were both the highest in snowfall and in snow cover, which were 229.36 and 259.31 μg/L respectively; the average value of ρ(Cd) were the lowest, which were 3.28 and 9.33 μg/L respectively. Compared with the environmental quality standards of surface water, the heavy metal concentrations in snowfall and snow cover showed a certain of exceeding the limits. The order of heavy metals concentrations in snowfall in different functional areas was followed as traffic area > industrial area > commercial area > residential area (with construction activity) > background area. The order of heavy metal concentrations in snow cover was followed as residential area (with construction activity) > industrial area > traffic area > commercial area > background area. Except for Fe, the heavy metals concentrations in snow cover were ranked as industrial area > traffic area > commercial area > residential area > background area. Based on the correlation and principal component analysis, heavy metals in snowfall came from the traffic emission, coal combustion and metal smelting, while heavy metals in snow cover came from coal combustion, traffic emission, metal smelting and steel production. The Backward Trajectory Model analysis showed that there were no typical pollution sources in the two types of air mass source areas, which indicated that pollutants in snowfall and snow cover of Urumqi came from the local sources.
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Key words:
- Snowfall /
- Snow Cover /
- Heavy Metal Pollution /
- Source Apportionment /
- Urumqi
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表 1 采样点和功能区划分
编号 采样点 功能区划分 采样点周边概况 1 农大 生活区(建筑活动) 采样点周边为居民生活与文教活动混合具有生活区的代表性 2 三屯碑 交通区 采样点临近乌鲁木齐最大的汽车客运站,运输车辆较多 3 大巴扎 商业区 采样点处于新疆地标性商圈内 4 友好路 商业区 采样点周边大型商场较多,私家车辆与公共交通密集 5 北门 商业区 采样点周边为小型商业设施集群,人流密集 6 北京路 交通区 采样点周边是城市快速公交系统的交汇处,车流量巨大 7 机场 交通区 采样点毗邻乌鲁木齐市机场 8 米东 工业区 采样点位于工业园区附近,工业设施繁复 9 八钢 工业区 采样点毗邻新疆最大的钢铁企业 10 南山 背景区 采样点位于牧场及旅游区附近,人为活动较少 表 2 采样期间气象条件
t/月-日 平均温度/℃ 平均相对
湿度/%主要风向 平均风速
/km·h–1样品类别 1-14 –13.33 86.19 NE 3.15 降雪 1-24 –9.40 74.29 SSE 6.61 积雪 2-15 –7.19 84.04 NW 3.54 降雪 2-25 –9.31 80.44 ENE 4.09 积雪 表 3 降雪、积雪重金属浓度及其变异系数
重金属种类 降雪平均ρ/μg·L–1 降雪范围ρ/μg·L–1 变异系数/% 积雪平均ρ/μg·L–1 积雪范围ρ/μg·L–1 变异系数/% Fe 229.63±186.13 30.99~808.20 81.06 259.31±268.96 13.07~1111.26 103.72 Zn 61.73±34.96 15.73~133.81 56.62 76.64±32.79 0.49~156.61 42.80 Pb 53.24±24.24 12.62~115.21 45.53 67.63±16.72 20.32~91.53 24.73 Ni 36.89±32.24 0.43~123.30 87.40 60.44±65.18 0.43~180.72 107.86 As 19.94±16.83 0.08~60.64 84.41 26.68±20.28 0.12~65.80 75.97 Cu 16.38±11.73 0.29~57.01 71.59 17.81±11.21 0.58~57.39 63.28 Cr 9.88±5.71 2.07~20.94 57.78 17.71±15.66 1.81~53.84 87.91 Cd 3.28±1.46 1.27~5.49 44.56 9.33±10.87 0.77~40.20 116.41 表 4 降雪中重金属之间的相关性分析
重金属种类 Cr As Zn Pb Ni Cu Cd Fe Cr 1.000 As –0.149 1.000 Zn –0.195 –0.186 1.000 Pb 0.475* 0.182 –0.262 1.000 Ni –0.038 0.045 0.732** –0.137 1.000 Cu 0.318 0.160 0.360 –0.091 0.343 1.000 Cd 0.415 0.176 –0.706** 0.547* –0.530* –0.197 1.000 Fe 0.256 0.618** –0.072 0.185 0.250 0.388 0.426 1.000 注:*表示相关性显著(P<0.05),**表示相关性极显著(P<0.01)。 表 5 积雪中重金属的相关性分析
重金属种类 Cr As Zn Pb Ni Cu Cd Fe Cr 1.000 As 0.770** 1.000 Zn 0.562** 0.598** 1.000 Pb 0.188 0.262 0.183 1.000 Ni 0.356 0.493* 0.313 0.248 1.000 Cu 0.532* 0.657** 0.394 0.375 0.385 1.000 Cd 0.743** 0.744** 0.394 0.278 0.609** 0.758** 1.000 Fe 0.394 0.379 0.423 0.570** 0.250 0.579** 0.553* 1.000 注:*表示相关性显著(P<0.05),**表示相关性极显著(P<0.01)。 表 6 降雪旋转成分矩阵
重金属 成分 F降1 F降2 F降3 Cr –0.138 0.146 0.911 As –0.267 0.718 –0.395 Zn 0.920 –0.035 –0.075 Pb –0.355 0.022 0.646 Ni 0.708 0.436 –0.186 Cu 0.342 0.757 0.299 Cd –0.794 0.150 0.418 Fe –0.015 0.900 0.240 表 7 积雪旋转成分矩阵
重金属 成分 F积1 F积2 F积3 Cr 0.272 0.829 –0.033 As 0.703 0.538 0.088 Zn 0.016 0.845 0.266 Pb 0.045 0.269 0.805 Ni 0.662 0.058 0.352 Cu 0.793 0.050 0.340 Cd 0.867 0.185 –0.096 Fe 0.258 –0.029 0.818 -
[1] TAIWO A M, HARRISON R M, SHI Z B. A review of receptor modelling of industrially emitted particulate matter[J]. Atmospheric Environment, 2014, 97: 109 − 120. doi: 10.1016/j.atmosenv.2014.07.051 [2] GÓMEZ E T, SANFELIU T, JORDÁN M M, et al. Geochemical characteristics of particulate matter in the atmosphere surrounding a ceramic industrialized area[J]. Environmental Geology, 2004, 45(4): 536 − 543. doi: 10.1007/s00254-003-0908-9 [3] NIU H W, HE Y Q, ZHU G F, et al. Environmental implications of the snow chemistry from Mt. Yulong, southeastern Tibetan Plateau[J]. Quaternary International, 2013, 313−314(10): 168 − 178. [4] 帕丽达•牙合甫, 马迪纳•海热提, 依明江•艾尔肯. 乌鲁木齐市积雪和降雪中BOD5和COD空间变化分析[J]. 新疆农业大学学报, 2015, 38(2): 152 − 156. doi: 10.3969/j.issn.1007-8614.2015.02.011 [5] 闫旭. 西安市大气、土壤、降水中重金属的污染特征研究[D]. 西安: 西安建筑科技大学, 2013. [6] DOLSKE D A, SIEVERING H. Trace element loading of southern Lake Michigan by dry deposition of atmospheric aerosol[J]. Water, Air and Soil Pollution, 1979, 12(4): 485 − 502. doi: 10.1007/BF01046869 [7] INJUK J, GRIEKEN R V. Atmospheric concentrations and deposition of heavy metals over the North Sea: A literature review[J]. Journal of Atmospheric Chemistry, 1995, 20(2): 179 − 212. doi: 10.1007/BF00696557 [8] ALPHEN M V. Atmospheric heavy metal deposition plumes adjacent to a primary lead-zinc smelter[J]. Science of the Total Environment, 1999, 236(1−3): 119 − 134. doi: 10.1016/S0048-9697(99)00272-7 [9] BALESTRINI R, GALLI L, TARTARI G. Wet and dry atmospheric deposition at prealpine and alpine sites in northern Italy[J]. Atmospheric Environment, 2000, 34(9): 1455 − 1470. doi: 10.1016/S1352-2310(99)00404-5 [10] DEBOUDT K, FLAMENT P, BERTHO M L. Cd, Cu, Pb and Zn concentrations in atmospheric wet deposition at a coastal station in Western Europe[J]. Water Air & Soil Pollution, 2004, 151(1−4): 335 − 359. [11] NICHOLSON F A, SMITH S R, ALLOWAY B J, et al. An inventory of heavy metals inputs to agricultural soil in England and Wales[J]. Science of the Total Environment, 2003, 311(1−3): 205 − 219. doi: 10.1016/S0048-9697(03)00139-6 [12] 王卫星, 曹淑萍, 李攻科, 等. 津北大气干湿沉降重金属元素通量与评价研究[J]. 环境科学与管理, 2017, 42(5): 46 − 51. doi: 10.3969/j.issn.1673-1212.2017.05.011 [13] PAN Y P. Atmospheric wet and dry deposition of trace elements at 10 sites in northern China[J]. Atmospheric Chemistry & Physics Discussions, 2015, 14(2): 951 − 972. [14] 叶艾玲, 程明超, 张璐, 等. 太原市夏季降水中溶解态重金属特征及来源[J]. 环境科学, 2018, 39(7): 3075 − 3081. [15] 帕丽达•牙合甫, 吴文权, 吐亚. 乌鲁木齐市交通干线积雪中硝酸盐氮的测定[J]. 环境化学, 2009, 28(1): 143 − 144. doi: 10.3321/j.issn:0254-6108.2009.01.032 [16] 帕丽达•牙合甫, 努尔比亚•藿加吾买尔, 麦麦提•斯马义. 乌鲁木齐采暖期TSP、PM10、PM5、PM2.5中重金属污染水平评价[J]. 中国环境监测, 2016, 32(5): 56 − 59. [17] MOAREF S, SEKHAVATJOU M S, HOSSEINI A A. Determination of trace elements concentration in wet and dry atmospheric deposition and surface soil in the largest industrial city, Southwest of Iran[J]. International Journal of Environmental Research, 2014, 8(2): 335 − 346. [18] HARRISON R M, TILLING R, ROMERO M S C, et al. A study of trace metals and polycyclic aromatic hydrocarbons in the roadside environment[J]. Atmospheric Environment, 2003, 37(17): 2391 − 2402. doi: 10.1016/S1352-2310(03)00122-5 [19] NRIAGU J O, PACYNA J M. Quantitative assessment of worldwide contamination of air, water and soils by trace metals[J]. Nature, 1988, 333(6169): 134 − 139. doi: 10.1038/333134a0 [20] CHENG K, WANG Y, TIAN H Z, et al. Atmospheric emission characteristics and control policies of five precedent-controlled toxic heavy metals from anthropogenic sources in China[J]. Environmental Science & Technology, 2015, 49(2): 1206 − 1214. [21] ESPEN L, PIROVANO L, COCUCCI S M. Effects of Ni2+ during the early phases of radish (Raphanus sativus) seed germination[J]. Environmental & Experimental Botany, 1997, 38(2): 187 − 197. [22] 赵晓韵. 大气降水中重金属形态分析及污染特征研究[J]. 科技通报, 2018, 34(3): 36 − 39+83. [23] 陆辉, 魏文寿, 崔彩霞, 等. 乌鲁木齐市东南郊一次降雪过程的化学组成及其悬浮态颗粒形态特征[J]. 环境科学, 2014, 35(4): 1223 − 1229. [24] ROBERT E L Jr, 吴德才. 大气中污染环境的重要金属来源[J]. 国外医学: 卫生学分册, 1983(6): 342 − 347. [25] HIEN P D, BINH N T, TRUONG Y, et al. Comparative receptor modelling study of TSP, PM2 and PM2-10 in Ho Chi Minh City[J]. Atmospheric Environment, 2001, 35(15): 2669 − 2678. doi: 10.1016/S1352-2310(00)00574-4 [26] TIAN H Z, WANG Y, XUE Z G, et al. Trend and characteristics of atmospheric emissions of Hg, As, and Se from coal combustion in China, 1980-2007[J]. Atmospheric Chemistry and Physics, 2010, 10(23): 20729 − 20768. [27] LIU G J, ZHENG L G, DUZGOREN-AYDIN N S, et al. Health effects of arsenic, fluorine, and selenium from indoor burning of Chinese coal[J]. Reviews of Environmental Contamination and Toxicology, 2007, 189: 89 − 106. [28] 乔宝文, 刘子锐, 胡波, 等. 北京冬季PM2.5中金属元素浓度特征和来源分析[J]. 环境科学, 2017, 38(3): 876 − 883. [29] 王艳, 程轲, 易鹏, 等. 中国工业过程大气铅排放特征[J]. 环境科学学报, 2016, 36(5): 1589 − 1594. [30] 赵莉斯, 于瑞莲, 徐玲玲, 等. 厦门海沧区PM2.5中金属元素污染评价及来源分析[J]. 环境科学, 2017, 38(10): 4061 − 4070. [31] COUNCELL T B, DUCKENFIELD K U, LANDA E R, et al. Tire-wear particles as a source of zinc to the environment[J]. Environmental Science & Technology, 2004, 38(15): 4206 − 4214. [32] 臧飞, 李萍, 薛粟尹, 等. 兰州市大气降尘重金属的分布特征及来源研究[J]. 兰州大学学报(自科版), 2016, 52(3): 357 − 363. [33] 殷汉琴, 周涛发, 陈永宁, 等. 铜陵市大气降尘中Cd元素污染特征及其对土壤的影响[J]. 地质论评, 2011, 57(2): 218 − 222. [34] TANG Q, Liu G J, Yan Z C, et al. Distribution and fate of environmentally sensitive elements (arsenic, mercury, stibium and selenium) in coal-fired power plants at Huainan, Anhui, China[J]. Fuel, 2012, 95(1): 334 − 339. [35] ITSKOS G, KOUKOUZAS N, VASILATOS C, et al. Comparative uptake study of toxic elements from aqueous media by the different particle-size-fractions of fly ash[J]. Journal of Hazardous Materials, 2010(1−3): 787 − 792. [36] 祁星鑫, 王晓军, 黎艳, 等. 新疆主要煤区煤矸石的特征研究及其利用建议[J]. 煤炭学报, 2010, 35(7): 1197 − 1201. [37] PACYNA J M, PACYNA E G, AAS W. Changes of emissions and atmospheric deposition of mercury, lead, and cadmium[J]. Atmospheric Environment, 2009, 43(1): 117 − 127. doi: 10.1016/j.atmosenv.2008.09.066 [38] 刘亚军, 张玉兰, 康世昌, 等. 青藏高原东南部冰川雪冰重金属元素特征[J]. 冰川冻土, 2017, 39(6): 1200 − 1211. [39] HE B, LIANG L N, JIANG G B. Distributions of arsenic and selenium in selected Chinese coal mines[J]. Science of the Total Environment, 2002, 296(1−3): 19 − 26. doi: 10.1016/S0048-9697(01)01136-6 [40] KOWALCZYK G S, GORDON G E, RHEINGROVER S W. Identification of atmospheric particulate sources in Washington, D. C. using chemical element balances[J]. Environmental Science and Technology, 1982, 16(2): 79 − 90. doi: 10.1021/es00096a005 [41] NORMAN M, DAS S N, PILLAI A G, et al. Influence of air mass trajectories on the chemical composition of precipitation in India[J]. Atmospheric Environment, 2001, 35(25): 4223 − 4235. doi: 10.1016/S1352-2310(01)00251-5