A Survey of Mercury in Air and Precipitation across Canada: Patterns and Trends

Atmosphere

Amanda S. Cole⁵  Alexandra Steffen⁵  Chris S. Eckley²  Julie Narayan⁵  Martin Pilote⁶  Rob Tordon³  Jennifer A. Graydon¹  Vincent L. St. Louis¹  Xiaohong Xu⁴ 

[1] Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada; E-Mails:;U.S. Environmental Protection Agency, Region 10, 1200 6th Ave, Seattle, WA 98101, USA; E-Mail:;Environment Canada, 45 Alderney Drive, Dartmouth, NS B2Y 2N6, Canada; E-Mail:;Department of Civil and Environmental Engineering, University of Windsor, 401 Sunset Ave., Windsor, ON N9B 3P4, Canada; E-Mail:;Air Quality Processes Research, Science & Technology Branch, Environment Canada, 4905 Dufferin St., Toronto, ON M3H 5T4, Canada; E-Mails:;Aquatic Contaminants Research Division, Environment Canada, 105 McGill, Montreal, QC H2Y 2E7, Canada; E-Mail:

关键词: elemental mercury;    total gaseous mercury;    reactive mercury;    gaseous oxidized mercury;    particulate mercury;    cycling of atmospheric mercury;    mercury in precipitation;    mercury trends;   

DOI  :  10.3390/atmos5030635

来源: mdpi

【 摘 要 】

Atmospheric mercury (Hg) measurements from across Canada were compiled and analysed as part of a national Hg science assessment. Here we update long-term trends of Hg in air and precipitation, and present more extensive measurements on patterns and trends in speciated Hg species (gaseous elemental mercury—GEM, reactive gaseous mercury—RGM, and total particulate mercury on particles <2.5 μm—TPM_2.5) at several sites. A spatial analysis across Canada revealed higher air concentrations and wet deposition of Hg in the vicinity of local and regional emission sources, and lower air concentrations of Hg at mid-latitude maritime sites compared to continental sites. Diel and seasonal patterns in atmospheric GEM, RGM and TPM_2.5 concentrations reflected differences in patterns of anthropogenic emissions, photo-induced surface emissions, chemistry, deposition and mixing. Concentrations of GEM decreased at rates ranging from −0.9% to −3.3% per year at all sites where measurements began in the 1990s. Concentrations of total Hg in precipitation declined up to 3.7% yr⁻¹. Trends in RGM and TPM_2.5 were less clear due to shorter measurement periods and low concentrations, however, in spring at the high Arctic site (Alert) when RGM and TPM_2.5 concentrations were high, concentrations of both increased by 7%–10% per year.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.