Meteorological Service of Canada, Environment Canada , 4905 Dufferin Street, Toronto, Ontario, M3H 5T4 Canada.
Environ Sci Technol. 2013 Sep 17;47(18):10339-48. doi: 10.1021/es401352n. Epub 2013 Sep 4.
The Flin Flon, Manitoba copper smelter was Canada's largest point source of mercury emissions until its closure in 2010 after ~80 years of operation. The objective of this study was to understand the variables controlling the local ground-level air mercury concentrations before and after this major point source reduction. Total gaseous mercury (TGM) in air, mercury in precipitation, and other ancillary meteorological and air quality parameters were measured pre- and postsmelter closure, and mercury speciation measurements in air were collected postclosure. The results showed that TGM was significantly elevated during the time period when the smelter operated (4.1 ± 3.7 ng m(-3)), decreased only 20% during the year following its closure, and remained ~2-fold above background levels. Similar trends were observed for mercury concentrations in precipitation. Several lines of evidence indicated that while smelter stack emissions would occasionally mix down to the surface resulting in large spikes in TGM concentrations (up to 61 ng m(-3)), the largest contributor to elevated TGM concentrations before and after smelter closure was from surface-air fluxes from mercury-enriched soils and/or tailings. These findings highlight the ability of legacy mercury, deposited to local landscapes over decades from industrial activities, to significantly affect local air concentrations via emissions/re-emissions.
曼尼托巴省弗林弗隆的炼铜厂是加拿大最大的汞排放点源，在运营约 80 年后于 2010 年关闭。本研究的目的是了解在这个主要点源减少之前和之后控制当地地面空气汞浓度的变量。在炼厂关闭前后测量了空气中的总气态汞（TGM）、降水中的汞以及其他辅助气象和空气质量参数，并在关闭后收集了空气中的汞形态测量值。结果表明，在炼厂运行期间（4.1±3.7ng m(-3))，TGM 显著升高，关闭后的第一年仅降低了 20%，并且仍保持在背景水平的 2 倍以上。降水中汞浓度也呈现出类似的趋势。有几条证据表明，尽管炼厂烟囱排放偶尔会混合到地面，导致 TGM 浓度的大幅上升（高达 61ng m(-3))，但在炼厂关闭前后导致 TGM 浓度升高的最大因素是来自富含汞的土壤和/或尾矿的地表空气通量。这些发现强调了数十年工业活动中沉积在当地景观中的汞残留物通过排放/再排放，对当地空气浓度产生重大影响的能力。
