Major Chemical Compositions of Spring Water on and around Mt. Iwate, Japan

Abstract

Major chemical compositions of the 35 spring waters on Mt. Iwate, Japan, were analyzed to explain chemical characteristics and their sources. Little seasonal change in water quality was detected from water samples repeatedly collected at the 12 springs. Spring waters were classified into three types by anion compositions as follow. Type I springs belong to Ca(HCO₃)₂ type and have relatively low ratio of SO₄^2-. Type II springs also belong to Ca(HCO₃)₂ type, but have relatively high ratio of SO₄^2-. Type III springs belong to CaSO₄,type. The type I and II springs were typical in water quality on Mt. Iwate. The type III springs are scarce and locate only around the fumaroles, indicating that the source of SO₄^2- is sulfuric compounds in the fumarolic gas such as H₂S and SO₂. Two possible sources of SO₄^2- in the type II springs were considered: one is the SO₄^2--rich Kakkonda river water which is used for irrigation at the south slope of Mt. Iwate, and the other is the sulfuric compounds in the fumarolic gas, which can be found of Kanazawa-shimizu and Oide springs.