Abstract
The water environment (volcanic island in particular) in the remote island is special from altitude, the topography, a permeable difference. All are volcanic islands, and, in Izu Islands, each island shows characteristic water environment, and there is a big difference by an island. Above all, Hachijojima, Mikurajima was blessed with fresh water environment, and the water which strongly received influence of water and the groundwater which strongly received influence of the rainwater was seen mainly there. In the island that was not blessed with other fresh water, I performed it mainly on an investigation into groundwater, and influence of water and the groundwater that the influence from the sea was big was divided into big water. There was particularly much SO4 and, in prosperous Izuoshima, Miyakejima of the volcanic activity, still showed the special quality of the water included in to some water, and influence from volcanic eject was seen. In the island that was not blessed with these fresh water, I was able to confirm a lot of swamps which died considered to appear only at the time of rain.The factor that has a big influence on water environment of Izu Islands has a much bigger influence (the progress number of years from the rain, a geological feature, the topography, the last eruption activity) more natural than human influence, and all of the islands are common in that, and it is big, and sea salt controls the quality of the water. In Miyakejima and a part of Izuoshima, SO4 considered to be related to the volcano greatly has an influence on the quality of the water exceptionally.
