[AHW34-P02] The influence of geology on river water quality and chemical loads in Oshika Village, Nagano, Japan
Keywords:geology, river water quality and load, heavy metal, ultramafic rock, crystalline schist, granite
From the trilinear diagram, water quality in the study area proved to be characterized by the Cl-, Ca2+ and Mg2+ concentration. A large amount of Cl- is loaded from the pelitic schist and green schist, while Mg2+ from the serpentinite. Also, a large amount of SiO2 is loaded from the diorite, gneiss, sandstone and mudstone, and Ni is loaded when the river flows down the area composed of the serpentinite, pelitic schist, sandstone and mudstone. Little loading of SiO2 was found from the serpentinite. The higher the areal proportion of the serpentinite in the drainage basin, the higher the Mg2+ concentration and the lower the Ca2+ and SiO2 concentration of the river water.