Background levels of atmospheric mercury in Kagoshima City, and influence of mercury emission from Sakurajima Volcano, Southern Kyushu, Japan

Vapor phase mercury concentration was determined daily for 1 year Jan. 1996]Jan. 1997. 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. The atmospheric mercury was collected on a porous gold collector at Kagoshima University and was determined by cold vapor atomic absorption spectrometry; Kagoshima University of Kagoshima City is located approximately 11 km west of Sakurajima Volcano. The mercury concentration obtained was in the range 1.2]52.5 ng my3 mean 10.8 ng my3, ns169.. The atmospheric concentration varied from season to season; the concentration was high in summer and lower in winter. A linear relation was obtained by plotting lnwHgrng my3 x vs. 1rT for the north, south and west winds with correlation coefficients of y0.76, y0.79 and y0.83, respectively, but no such dependency was found for the east wind rsy0.035.. When the wind is blowing from the east, Kagoshima City is on the leeward side of the volcano. The impact of the fumarolic activity of the volcano on ambient air in the city was evident in the disappearance of temperature dependency with the appearance of the east wind. Atmospheric mercury concentration except for the east wind was considered to be background levels of Kagoshima City. As background levels, 8.1"5.3 ng my3, 14.8"7.9 ng my3, 13.9"11.7 ng my3 and 4.4"1.6 ng my3 mean"S.D.. were obtained for spring, summer, autumn and winter, respectively