Abstract
Mercury is easy to spread worldwide via atmospheric long-range transport. In general, mercury is emitted from several sources into the atmosphere as a gaseous elemental mercury (GEM: 95% in atmosphere) and spread worldwide. The other 5% in the atmosphere exists as a form of gaseous oxidized mercury (GOM, Hg(II)) or/and particulate mercury (p-Hg) in the atmosphere. They are removed from the atmosphere as a dry/wet deposition. In order to clarify the fluctuation of the mercury concentration in rain water, we collected rain water in northern Shiga prefecture. We collected it using an automatic rain sampler developed by Nagafuchi and Tanabe which can separate every 5 mm of precipitation during single rain events. We analyzed both the total mercury (T-Hg) and dissolved (D-Hg) concentration level in the rain water. The majority of the mercury in the rain water was Hg(II). The average concentration of Hg(II) was 4.34±1.63 ng/L. The Hg(II) concentration only slightly fluctuated. The fluctuations of the mercury concentration in every 5 mm of precipitation were totally different in each run. In addition, in even single rain events, the mercury concentration showed various trends.
