| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 1998: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1997: ¥2,400,000 (Direct Cost: ¥2,400,000)
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| Research Abstract |
In this study, the vertical variations of mercury and organic matter contents in soils of Sakurajima, Takatouge (located at about 11 km south east of Sakurajima Volcano) and Suzu-yama (located at about 22 km south west of Sakurajima Volcano) were investigated. The soil samples were taken by 1 cm from the surface to about 1 m depth. At about 1 m depth, pumice layer of Taisho eruption (1914) was observed in Sakurajima, while in Takatouge a layer at the depth is of about 1200 years ago and in Suzu-yama is of 11000 years ago.
The mercury concentration in soil obtained for Sakurajima, Takatouge and Suzu-yama was in the ranges 0.42 - 27.9 ng g^<-1> (mean 6.6 ng g^<-1>, n 335), 2.93 - 75.1 ng g^<-1> (mean 29.0 ng g^<-1>, n = 100) and 7.61 - 494 ng g^<-1> (mean 229 ng g^<-1>, n 103), respectively, and the organic matter content was in the ranges 0.0 - 4.0% (mean 0.59%), 0.4 - 10.8% (mean 3.8%) and 0.0 - 23.6% (mean 4.9%), respectively. A high positive correlation was observed between mercury and organic matter contents with the correlation coefficient of 0.62 -'0.94 for Sakurajima and Takatouge soils.
Vapor phase mercury concentration was determined daily throughout a year in order to present the levels of atmospheric mercury in Kagoshima City and to estimate the influence of mercury emission from Sakurajima Volcano, southern Kyushu, Japan. Linear relation was obtained by plotting ln (Hg I ng m^<-3>) vs. 1/T in the north, the south and the west wind sectors with correlation coefficients of -0.77, -0.79 and -0.83, respectively, whereas the temperature dependency of mercury concentration disappeared in the east wind sector (r = -0.035). When it is blowing from the east, Kagoshima City become to the leeward of Sakurajima Volcano. The impact of fumarolic activity of Sakurajima Volcano on ambient air in Kagoshima City was documented by the disappearance of the temperature dependency in the east wind.
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