Subscriber access provided by University of Newcastle, Australia
Article
Seasonal and annual variations in atmospheric Hg and Pb isotopes in Xi’an, China Hongmei Xu, Jeroen E. Sonke, Benjamin Guinot, Xuewu Fu, Ruoyu Sun, Aurelie Lanzanova, Frederic Candaudap, Zhenxing Shen, and Jun-ji Cao Environ. Sci. Technol., Just Accepted Manuscript • DOI: 10.1021/acs.est.6b06145 • Publication Date (Web): 02 Mar 2017 Downloaded from http://pubs.acs.org on March 5, 2017
Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.
Environmental Science & Technology is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.
Page 1 of 39
Environmental Science & Technology
TOC Figure 209x151mm (150 x 150 DPI)
ACS Paragon Plus Environment
Environmental Science & Technology
Figure 1. Temporal variations of TSP and PbTSP concentrations (conc., upper panel), particulate and total gaseous Hg concentrations, and 206Pb/207Pb ratio (middle panel), and particulate and total gaseous Hg isotopes (δ202Hg, ∆199Hg) during the sampling period in Xi’an. 1044x771mm (144 x 144 DPI)
ACS Paragon Plus Environment
Page 2 of 39
Page 3 of 39
Environmental Science & Technology
Figure 2. Summary of published aerosol Pb (µg m-3) observations in Xi’an. Data4, 42 were made on PM2.5, whereas this study measured TSP. The ensemble of observations points at a steady decline in winter time aerosol Pb of about 5% per year over the 2003-2012 period (r2 = 0.31). 1381x677mm (144 x 144 DPI)
ACS Paragon Plus Environment
Environmental Science & Technology
Figure 3. Scatter plots of isotopic ratios of Pb (208Pb/206Pb and 206Pb/207Pb) for TSP samples collected from Nov. 2009 to Oct. 2012 in Xi’an and for potential Pb pollution sources47-50, 62-66 in China. (the Chinese Pb line was drawn using the data for major lead mines in China48). 360x263mm (96 x 96 DPI)
ACS Paragon Plus Environment
Page 4 of 39
Page 5 of 39
Environmental Science & Technology
Figure 4. δ202Hg and ∆199Hg signatures of TGM (●) and HgTSP (■) in Xi’an and at other locations (diverse filled symbols). The dark black striped line (∆199Hg = -0.2×δ202Hg - 0.1) represent the mixing line between the Northern Hemisphere (NH) background TGM and recent industrial TGM emissions discussed in the text. Also shown are coal samples (▲) from three Shaanxi coal mines that supply Xi’an domestic and industrial coal use18, 23, 39, 51, 52, 54-57. 303x189mm (90 x 90 DPI)
ACS Paragon Plus Environment
Environmental Science & Technology
Figure 5. a): δ202HgTGM (‰) as a function of TGM concentration (ng m-3) in Xi’an. b): linearized (1/THg) binary isotope mixing diagram between the Northern Hemispheric background TGM (■, 1.4 ng m-3; δ202HgTGM of 0.47 ± 0.45‰, 2σ) and local Xi’an urban-industrial TGM emissions, represented by Shaanxi coal (▲, δ202HgShaanxi coal of -0.67 ± 0.28‰, 2σ, and assuming no shift in δ202Hg between coal Hg and emitted TGM). 266x81mm (150 x 150 DPI)
ACS Paragon Plus Environment
Page 6 of 39
Page 7 of 39
Environmental Science & Technology
Seasonal and annual variations in atmospheric Hg and Pb isotopes in Xi’an, China
Hongmei Xu1,2,4, Jeroen E. Sonke3*, Benjamin Guinot4, Xuewu Fu6,3, Ruoyu Sun5,3, Aurélie Lanzanova3, Frédéric Candaudap3, Zhenxing Shen1, Junji Cao2*
1
Department of Environmental Science and Engineering, Xi’an Jiaotong University,
Xi’an, China 2
Key Lab of Aerosol Chemistry & Physics, SKLLQG, Institute of Earth Environment,
Chinese Academy of Sciences, Xi’an, China 3
Observatoire Midi-Pyrénées, Laboratoire Géosciences Environnement Toulouse,
CNRS/IRD/Université de Toulouse, France 4
Laboratoire d'Aérologie, Université de Toulouse, CNRS, UPS, France
5
Institute of Surface-Earth System Science, Tianjin University, Tianjin 300072, China
6
State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry,
Chinese Academy of Sciences, Guiyang, 550081, China
*Corresponding authors: Jeroen E. Sonke:
[email protected], 14 avenue Edouard Belin, 31400 Toulouse, France, t.:+33(0)561332606, f.:+33(0)561332560; Junji Cao:
[email protected], 97 Yanxiang Road, Xi’an, 710061, Shaanxi, China, t.: +86(29)62336205, f.: +86(29)62336234.
1
ACS Paragon Plus Environment
Environmental Science & Technology
Abstract We present a 3-year time series of lead (Pb) and mercury (Hg) concentrations and isotope signatures in total suspended particulate (TSP) matter and as total gaseous Hg (TGM) in Xi’an, Northwestern China. Mean concentrations of TSP (299 ± 120 µg m-3), PbTSP (0.33 ± 0.15 µg m-3) and HgTSP (0.64 ± 0.54 ng m-3), and TGM (5.7 ± 2.7 ng m-3) were elevated. We find that atmospheric Pb levels in Xi’an have decreased by 4.6% per year since 2003, yet remain elevated relative to air quality guidelines and therefore a major health concern. δ202HgTSP and ∆199HgTSP averaged -0.80 ± 0.30 ‰ (1σ) and -0.02 ± 0.10 ‰ (1σ) and δ202HgTGM and ∆199HgTGM averaged -0.08 ± 0.41 ‰ (1σ) and 0.00 ± 0.04 ‰ (1σ). Relative to raw coal from Shaanxi and surrounding provinces, δ202HgTSP is enriched in the light Hg isotopes, while δ202HgTGM is enriched in the heavy isotopes. TSP and TGM ∆199Hg signatures are indistinguishable from raw coal, indicating little photochemical mass independent fractionation of atmospheric Hg in the near-field urban-industrial environment. δ202HgTGM correlates significantly with TGM levels (r2 = 0.3, p
