Amounts of Mercury Discharged to Atmosphere from Fumaroles and Hot Spring Gases in Geothermal Areas

Abstract

This research seeks to clarify the background levels for natural abundance of mercury in gases discharged to the atmosphere from geothermal areas (Shimokita penin. and Hachimantai, Northern Tohoku dist.; Kusatsu-Shirane and Hakone-Owakudani, Kanto dist.; TateyamaJigokudani, Hokuriku dist.; Beppu, Aso, Otake, Unzen and Kirishima, Kyushu dist. ) of Japan and also will provide basic data, to allow comparison with the situation five or ten years later, for the planning to elucidate the acutual conditions of man-made sources.
The amount of mercury discharged from fumarolic gases, bases upon 72 samples taken during 1980-1983, ranged from 0.096 to 1020 μg/m3 with an average value of 75 Atglm3. Mercury contents in steam condensates ranged from 0.08 to 4.8 gel (av.1.3 μg/l) and those distribution values were less than 1400 of mercury discharged from fumarolic gases. The amount of mercury discharged from hot spring gases ranged from O.078 to 6.5 μg/m3 (av.0.75 μg/m3)and the temperature of hot spring waters were proved to be important as a factor controlling the mercury content of hot spring gases. Mercury contents of air in the geothermal areas were ranged from O.045 to 7.3, μg/m3 and those values were 3 to 500 times as large as the mercury content of ordinary urban ambient air. Rough estimate of the volcanogenic con tribution of mercury released to the atmosphere from volcanic gas sources was 5% by analyti cal results of the fumarolic gases. t Studies on Mercury of Hot Springs. III.