Arsenic concentration in hot spring waters from the Niigata Plain and Shinji Lowland, Japan; source supply of arsenic in arsenic contaminated ground water problem; Part 2

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Authors:Kubota, Yoshihiro; Yokota, Daiki; Ishiyama, Yutaka
Author Affiliations:Primary:
Niigata University, Department of Environmental Science, Niigata, Japan
Other:
NS Environmental Science Consultant Corporation, Japan
Niigata Prefectural Office, Japan
Volume Title:Chikyu Kagaku Earth Science
Source:Chikyu Kagaku = Earth Science, 55(1), p.11-22. Publisher: Chigaku Dantai Kenkyu-kai, Tokyo, Japan. ISSN: 0366-6611
Publication Date:2001
Note:In Japanese with English summary. 35 refs.; illus., incl. 5 tables, geol. sketch maps
Summary:The purpose of this study is to investigate the distribution of arsenic concentration in hot spring waters from the Niigata Plain, central Japan and the Shinji Lowland, western Japan and to consider the origin of arsenic supply for groundwaters in the modern sedimentary basins. The hot springs distributed in the inner area of the Niigata Plain have low temperature (11 to 40°C) and low As content (0.1 to 10 ppb). However, hot springs in the inner area of the Shinji Lowland have middle to high temperature (40 to 85°C) and middle to high As content (10 to 114 ppb). The As contents in the Shinji Lowland hot springs are about ten to hundred times higher than those in the Niigata Plain. The hot spring distribution pattern, geology, and the arsenic content of hot spring waters closely depend on geological structure under the both plains. In the granitoid and green tuff areas, the temperature and arsenic concentration of hot spring waters are high compared to the Tertiary and Quaternary sediment areas. The hot springs are distributed along deep fracture zones at the margins of the plains. It is considered that the hot spring waters is the mixture of underground geothermal water from the basement fractures and ground waters of meteoric origin. Arsenic is eluted from the basement rocks into the geothermal water. In the eastern part of the Shinji Lowland hot spring waters with high temperature and high concentration of arsenic appear at hot springs upwelling from depth near the basement rocks. This shows that the arsenic concentration is controlled by the mixing rates of the meteoric water and geothermal water. The low arsenic concentration in the Niigata Plain compared with the Shinji Lowland is mainly due to the low arsenic content of the geothermal water. It is also due to the tick sedimentary rocks overlying basement rocks which reaches 7,000 m or more below the surface.
Subjects:Arsenic; Concentration; Geochemistry; Ground water; Hot springs; Hydrochemistry; Metals; Pollutants; Pollution; Springs; Thermal waters; Asia; Far East; Honshu; Japan; Niigata Japan; Shimane Japan; Shinji Lake; Niigata Plain; Shinji Lowland
Coordinates:N375800 N375800 E1390200 E1390200
N352600 N353000 E1330300 E1325000
Record ID:2001071465
Copyright Information:GeoRef, Copyright 2018 American Geosciences Institute.
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