The concentrations of lead and cadmium in the tree bark from Sanming and Xiamen, Fujian province, China were determined by atomic fluorescence spectrometry and inductively coupled plasma mass spectrometry. The results obtained in the outer tree bark and tree bark pocket could reflect the degree of present and historical air pollution at different sampling locations. Tree bark and tree bark pocket should be expected to be as a useful biomonitor of present and historical condition of air pollution

佐竹研一

朱晨

李振基

王宇

王秋泉

角田欣一

黄志勇

黄本立

Xiamen University Institutional Repository

　　A NOVEL SAMPLING METHOD FOR PRESENT ANDHISTORICAL MONITORING OF AIR POLLUTION BYUSING TREE BARK1)WANG Qiu2quan2) 　ZHU Chen 　WANG Yu 　HUANG Zhi2yong 　LI Zhen2ji 　HUANG Ben2li(Department of Chemistry &the MOE Key Laboratory of Analytical Sciences , Xiamen University , Xiamen , 361005)TSUNODA Kin2ichi(Department of Chemistry , Gunma University , Kiryu 376 - 8515 , Japan)SATA KE Kenichi(National Institute for Environmental Studies , Onogawa 1622 , Tsukuba 305 —8506 , Japan)Abstract 　The concentrations of lead and cadmium in the tree bark from Sanming and Xiamen , Fujianprovince , China were determined by atomic fluorescence spectrometry and inductively coupled plasmamass spectrometry. The results obtained in the outer tree bark and tree bark pocket could reflect the de2gree of present and historical air pollution at different sampling locations. Tree bark and tree bark pocketshould be expected to be as a useful biomonitor of present and historical condition of air pollution.Keywords : air pollution monitoring , tree bark , tree bark pocket , lead , cadmium.1 　IntroductionBesides the usual sampling methods , the concentrations of pollutants in tree bark and tree barkpocket have been proposed for evaluating the degree of air pollution of present and in the past[1 —4 ] .In this study the concentrations of lead and cadmium in the outer tree barks of redbud , whichwere collected in Sanming , Fujian province , China , were determined by atomic fluorescence spec2trometer (AFS) and inductively coupled plasma mass spectrometry ( ICP2MS) , and the results wereused to evaluate the degree of air pollution around the sampling sites. Moreover , the concentrationsof lead and cadmium and the isotope ratios of 206 Pb/ 208 Pb and 206 Pb/ 207 Pb in the mango tree barkpocket were respectively determined for historical monitoring of air pollution and recognizing the leademission sources in Xiamen , Fujian province , China.2 　Experimental211 　Chemicals ant instrumentsStandard solution of lead and cadmium were prepared by dissolving an appropriate amount ofspecpure lead and cadmium in 7 mol·l - 1 HNO3 , and diluted by Milli2Qwater (Millipore , Bedford.　　1) This study was financially supported by Nissan Science Foundation and Science and Technology Developing Project of XiamenMunicipal Government (2003201) .2) Corresponding author. Tel : 059222181796 ; E2mail : qqwang @jingxian. xmu. edu. cn.第 22 卷 　第 3 期2003 年 　　 5 月环 　境 　化 　学ENVIRONMENTAL CHEMISTRYVol. 22 , No. 3 　May 　　　2003 　MA , USA) to 100 ml in a polyethylene bottle to give 1000μg·ml - 1 Pb and Cd solutions in 2 %HNO3 , respectively. Pb isotope standard reference material SRM 981 (NIST) was used for calibra2tion during determination of Pb isotope ratios. Thallium standard stock solution of 1000μg·ml - 1( GSB G62070290 (8101) , National Analytical Center for Steel Materials , China) was used as in2ternal standards during ICP2MS determination. A certified reference material GBW07603 of treeleaves was used to ensure AFS and ICP2MS in good conditions.A Hewlett2Packard ( Yokogawa Analytical Systems , Tokyo , Japan) 4500 ICP2MS system fittedwith a concentric nebulizer kit was used for the determination of lead and its isotope ratios.Cadmium was determined by ASF 2002 (Beijing Vital Instrumental Co. Ltd. , China) with a FIAsample introduction system of hydride generation , and a cadmium high strength HCL lamp (No. 12Institute of Electronics , Beijing , China) was used as a excitation source ,λex = 22818 nm.212 　Sample collection and pre2treatmentTree bark and tree bark pocket samples were collected at the industrial area of Sanming and ur2ban area of Xiamen , Fujian province , China. After sampling the tree barks were divided into fourparts of outer bark , inner bark , cambium and wood , and then the outer tree barks were put into a60 ℃ stove for drying until constant weight were attained. An appropriate amount between 100 —200mg of the dried sample was put into a double layer Teflon digestion bomb , which contained 015 —210ml high purity concentrated HNO3 in the outer layer. After 4h digestion at 140 ℃, the left onedrop of residue in the inner Teflon vessel was diluted with Milli2Q water , filtered through a 0145μmmembrane , and finally diluted to 10ml for further determination.3 　Results and discussion311 　Lead and cadmium in the outer tree barks in SanmingPollutants in airborne could deposit into the outer bark of a tree through two ways : dry deposi2tion (gases and particles) and wet deposition (rain , snow , fog , and mist) . The concentrations ofpollutants in it might reflect the degree of air pollution at present time. Sanming city was built in avalley located in the southeastern part of China , a heavy industrial base in the central part of Fujianprovince. Shaxi river crosses the city from southwest to northeast , and wind blows from northeast tosouthwest all the time in a year. The northeastern side of Shaxi river is the industrial area havingmany big smelters , steel plants , chemical factories , and the other side is the living area for citizen.Redbud tree barks was collected from the lower to the upper along Shaxi river. Tree bark samples ofpine were also collected at different height above sea level on Hutou mountain near Shaxi river.The concentrations of lead and cadmium in the outer tree barks collected in Sanming wereshown in Fig. 1 indicating that lead and cadmium concentrations determined in the outer bark variedaccording to the sampling locations. Both of the concentrations of lead and cadmium in the outer treebarks collected along Shaxi river increase in general along the wind direction (Fig11 (a) ) , this phe2nomenon is in agreement with the fact that pollutants may concentrate at the site at the down direc2tion of wind. However , those on Hutou mountain have two peaks at 380m and 1020m above sea le2152　3 期 王秋泉等 : 利用“树皮”进行大气污染历史监测的新采样方法vel (Fig11 (b) ) . It might be because of air convection , but the reason has not been clear so far.Fig. 1 　Concentrations of Pb and Cd in the outer tree barks of redbud along Shaxi river (a)and in the outer tree barks of pine on Hutou mountain (b)312 　Lead and cadmium in mango tree bark pocket in XiamenAs mentioned above the concentrations of pollutants in the outer tree bark might reflect the de2gree of air pollution at present ; furthermore those in the outer tree bark of the tree bark pocket en2closed in a tree trunk could offer the information of the degree of air pollution in the past . The timeof the tree bark pocket may be dated by the annual ring of a tree. A mango tree bark pocket samplewas collected in the urban area of Xiamen. The concentrations of lead and cadmium in the tree barkpocket from 1993 to 2001 were shown in Fig12. The results in Fig12 indicated that both concentra2tions of lead and cadmium in the bark pocket are relative high in the years of 1995 and 2000 , re2flecting that air pollutions of the two years are relative more serious in Xiamen.Fig. 2 　Concentrations of lead and cadmium in mango tree bark pocket in Xiamen313 　Isotope analysis of lead in the mango tree bark pocketThere are almost no heavy industries in Xiamen. The possible sources of pollutants are the ex2haust gases from thermal stations , automobiles and waste incineration as well as transportation fromother areas. To distinguish the possible sources of lead pollution in Xiamen , isotope analysis of leadby ICP2MS was performed. The results of 206Pb/ 207Pb and 206Pb/ 208Pb in the mango tree bark pocketfrom 1993 to 2001 were illustrated in Fig13. Clearly , both of 206 Pb/ 207 Pb and 206 Pb/ 208 Pb in the252 环 　　境 　　化 　　学 　　　　　　　　　　　　22 卷mango tree bark pocket from 1999 to 2001 are lower that those from 1993 to 1998. The ratios of206Pb/ 207 Pb in the petrol with the Pb additives that imported from Europe countries and USA arefrom 1110 to 1121[5 - 7 ] , and that in the earth crust of China is about 1119[8 ] , however there is nothe values for waste incineration recorded in China now. From 1999 Xiamen municipal governmentdecided to stop using the leaded petrol (gasoline) , this might be one of the reasons why the ratiosbegan to decrease from the year. However , the concentrations of lead did not decrease from 1999(Fig. 2 (a) ) , and that in 2000 is very high. Such a phenomenon implies that there must be othersources of lead in Xiamen besides the automobiles and thermal stations , the contribution from wasteincineration[4 ] , which is recently used for waste disposal in Xiamen , should be also taken into ac2count for the total amount of lead and the reduction in the ratios of 206Pb/ 207Pb.Fig. 3 　Isotope ratios of 206Pb/ 207 Pb and 206Pb/ 208Pb in the mango tree bark pocket4 　ConclusionsTree bark and tree bark pocket are effective biomonitor for evaluating air pollution. The con2centrations of pollutants in the tree bark and tree bark pocket may provide valuable information onpresent and historical condition of air pollution. Moreover , with such a sampling method isotopeanalysis technique could be applied to identifying the sources of pollutants.Authors thank Dr. David J . Bellis of National Institute for Environmental Studies and Dr. Tomonari Umemura ofGunma University of Japan for valuable discussions.References[ 1 ] Satake K, Tanaka A , Kimura K, Accumulation of Lead in Tree Trunk Bark Pockets as Pollution Time Capsules. Sci . To2tal Environ . , 1996 , 181∶25 —30[ 2 ] Bellis D J , McLeod C W , Satake K, The Potential of Elemental and Isotopic Analysis of Tree Bark for DiscriminatingSources of Airborne Lead Contamination in the UK. J . Environ. Monit . , 2001 , 3∶194 —197[ 3 ] Bellis D J , McLeod C W , Satake K, Pb and 206 Pb/ 207 Pb Isotopic Analysis of a Tree Bark Pocket near Sheffield , UKRecording Historical Change in Airborne Pollution during the 20th Century. Sci . Total Environ . , 2002 , 289∶169 —176[ 4 ] Bellis D J , Satake K, Noda M et al . , Evaluation of Historical Records of Lead Pollution in the Annual Growth Rings andBark Pockets of a 2502Year2Old Quercus Crispula in Nikko , Japan. Sci . Total . Environ . , 2002 , 295∶91 —100352　3 期 王秋泉等 : 利用“树皮”进行大气污染历史监测的新采样方法[ 5 ] Elbaz2Poulichet F , Holliger P , Martin J M et al . , The Stable Lead Isotopes Ratios in Major French Rivers and Estuaries.Sci . Total Environ . , 1986 , 54∶61 —76[ 6 ] Sturges W T , Barrie L A , Lead 206/ 207 Isotope Ratios in the Atmosphere of North America as Tracers of US and CanadianEmissions. Nature , 1987 , 329∶144 —146[ 7 ] Mukai H , Furuta N , Fujii T et al . , Characterization of Sources of Lead in the Urban Air of Asia Using Ratios of Stable LeadIsotopes. Environ. Sci . Technol . , 1993 , 27∶61 —68[ 8 ] Li L , Zheng Y F , Zhou J B , Dynamic Model for Pb Isotope Evolution in the Continental Crust of China. Acta PetrologicaSinica , 2001 , 17∶61 —68利用‘树皮’进行大气污染历史监测的新采样方法王秋泉 , 朱晨 , 王宇 , 黄志勇 , 李振基 3 , 黄本立厦门大学化学系 , 教育部现代分析科学重点实验室 , 厦门 , 361005 ( 3 厦门大学生物系)角田欣一Department of Chemistry , Gunma Univeristy , Kiryu 376 —8515 , Japan佐竹研一National Institute for Environmental Stadies , Onogawa 1622 , Tsukuba 305 —8506 , Japan452 环 　　境 　　化 　　学 　　　　　　　　　　　　22 卷

利用‘树皮’进行大气污染历史监测的新采样方法(英文)

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利用‘树皮’进行大气污染历史监测的新采样方法(英文)

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