Mercury Wet Deposition in Chuncheon, Korea: Concentration in Rain and Washout Ratio

초록

Wet deposition is the primary pathway for mercury (Hg) input to aquatic ecosystem. In this study, rainfall samples were collected for about 3 years, and the total mercury (Hg(T)) concentrations in rain were measured to quantify the wet deposition flux in Chuncheon, Korea. The volume weighted mean (VWM) Hg(T) concentration was 6.1 ng/L over the entire sampling period. Precipitation depth was negatively correlated with Hg(T) concentration in rain especially during winter, suggesting that the atmospheric Hg was effectively scavenged by initial rainfall or snowfall in winter. In the summer and fall of 2016, very high Hg wet deposition flux was observed due to the high VWM Hg(T) in rain, and the back-trajectories were shown to pass through the areas where the fossil fuel power plants and cement industries are located. Concentrations of atmospheric gaseous oxidized mercury (GOM) were more than 10 times lower than those of particulate bound mercury (PBM) in this study. There was no correlation between atmospheric GOM and Hg(T) in rain while significant correlation between atmospheric PBM and Hg(T) in rain was observed. The washout ratio of PBM was estimated as 386 m(3)-air/L-rain.

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