Department of Natural Resources and Environmental Sciences, University of Nevada-Reno, 1664 North Virginia Street, Reno, Nevada 89557, United States.
Environ Sci Technol. 2012 Jun 19;46(12):6621-9. doi: 10.1021/es3005915. Epub 2012 Jun 7.
Mercury (Hg) in wet deposition in the United States is measured as part of the National Atmospheric Deposition Program--Hg Deposition Network (MDN). This study focused on compiling and assessing data collected since 2003 at two sites in Nevada, and at one in Nevada and three in Idaho where data were collected over shorter time intervals. At all locations the highest volume weighted concentrations and deposition were observed in the summer, a time of low precipitation, but high gaseous oxidized Hg (GOM) concentrations. Detailed assessment of high Hg wet deposition events showed variability across the region and higher deposition at the higher elevation sites. Potential Source Contribution Function analyses showed no specific point sources associated with the high Hg wet deposition events, but air masses derived predominantly from the southwest. Although this region has potential local and regional sources of GOM, detailed back trajectory analyses, the environmental setting of Nevada, results from other studies in Nevada, and GEOS-Chem modeling results point toward a free troposphere contribution to mercury in wet deposition input to this area of the western United States.
美国湿沉降中的汞（Hg）是作为国家大气沉降计划——汞沉降网络（MDN）的一部分进行测量的。本研究重点是整理和评估自 2003 年以来在内华达州的两个地点以及内华达州和爱达荷州的三个地点收集的数据，这些地点的数据收集时间较短。在所有地点，夏季观测到的最高体积加权浓度和沉降量最高，此时降水较少，但气态氧化汞（GOM）浓度较高。对高 Hg 湿沉降事件的详细评估表明，该地区存在很大的变异性，高海拔地区的沉降量更高。潜在源贡献函数分析表明，与高 Hg 湿沉降事件相关的特定点源，但空气团主要源自西南部。尽管该地区有 GOM 的局部和区域潜在源，但详细的后轨迹分析、内华达州的环境背景、内华达州的其他研究结果以及 GEOS-Chem 模拟结果表明，对美国西部这一地区湿沉降输入中汞的贡献来自自由对流层。
