Study of hot spring ingredient outflow into river for understanding of its environmental load and influence to ecosystem

2015 Fiscal Year Final Research Report

• Project/Area Number: 25340057
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Environmental impact assessment
• Research Institution: Kyoto University
• Principal Investigator: Ohsawa Shinji 京都大学, 理学(系)研究科(研究院), 教授 (30243009)
• Co-Investigator(Renkei-kenkyūsha): YAMADA Makoto 奈良女子大学, 共生科学研究センター, 非常勤研究員 (50434981) ; OUE Kazutoshi 大分大学, 教育福祉科学部, 準教授 (20583876)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 温泉 / 河川 / 水質 / 有用金属元素 / 有害元素 / 流出量 / 珪藻 / 因子分析

Outline of Final Research Achievements

From this study, it becomes understood that the rivers in the biggest hot spring area in Japan, Beppu, are strongly affected by hot spring drainage discharged from boiling hot springs existing in sewage unimproved area. The drainage of unused hot spring water from the boiling hot springs all the time is suspected of having a hand in the affair. Annual emission rates of Li, Cs and Rb, which are mainly derived from boiling hot spring water and useful metallic elements, are 34，0.4 and 5.4 tons, respectively, whereas those of As and B, which are also originated from boiling hot spring water, are 4.3 and 82 tons, respectively. This study made it clear that inflows of hot spring drainage into rivers cause increase of diatom amount in several rivers in Beppu, and annual discharge rate of the diatom to the Beppu Bay is estimated to be more than 10 tons a year.

Free Research Field

地球流体化学