Landis Matthew S, Vette Alan F, Keeler Gerald J
The University of Michigan Air Quality Laboratory, Ann Arbor 48109, USA.
Environ Sci Technol. 2002 Nov 1;36(21):4508-17. doi: 10.1021/es011216j.
The relative importance of the Chicago/Gay urban area was investigated to determine its impact on atmospheric mercury (Hg) concentrations and wet deposition in the Lake Michigan basin. Event wet-only precipitation, total particulate, and vapor phase samples were collected for Hg, and trace element determinations from five sites around Lake Michigan from July 1994 through October 1995 as part of the Lake Michigan Mass Balance Study (LMMBS). In addition, intensive over-water measurements were conducted aboard the EPA research vessel Lake Guardian during the summer of 1994 and the winter of 1995 as part of the Atmospheric Exchange Over Lakes and Oceans Study. Atmospheric Hg concentrations were found to be significantly higher in the Chicago/Gary urban area than surrounding sites: Hg in precipitation was a factor of 2 and particulate Hg was a factor of 6 times higher. Overwater measurements found elevated Hg concentrations 19 km off shore of Chicago/Gary suggesting an enhanced near field atmospheric deposition to Lake Michigan. Meteorological transport analyses also determined that local sources in the Chicago/Gary urban area significantly impacted all of the LMMBS sites indicating a broad impact to the entire Lake Michigan basin.
为了确定芝加哥/加里市区对密歇根湖流域大气汞（Hg）浓度和湿沉降的影响，对其相对重要性进行了调查。作为密歇根湖质量平衡研究（LMMBS）的一部分，于1994年7月至1995年10月从密歇根湖周边的五个地点采集了仅针对降雨事件的湿沉降、总颗粒物和气相样本，用于汞及微量元素的测定。此外，作为湖泊和海洋大气交换研究的一部分，1994年夏季和1995年冬季在环境保护局的研究船“湖泊守护者”号上进行了密集的水上测量。结果发现，芝加哥/加里市区的大气汞浓度显著高于周边地点：降水中的汞含量高出2倍，颗粒物汞含量高出6倍。水上测量发现，在距芝加哥/加里海岸19公里处汞浓度升高，这表明密歇根湖近岸大气沉降增强。气象传输分析还确定，芝加哥/加里市区的本地源对LMMBS的所有站点都有显著影响，这表明对整个密歇根湖流域有广泛影响。
