地下水汚染の予測・評価事例(実務編) : 山間農村地域における地下水の硝酸性窒素汚染事例(特集論説)

概要

論文の詳細を見る
Nitrate pollution of groundwater was investigated in the Toyooka-mura district in Nagano Prefecture in 2004. Ina formation (a fan deposit of Pliocene to Pleistocene) is the main aquifer in this district. The aquifer is divided into upper and lower members by an impermeable bed called Misobeta member, of which thickness is from 2 to 12 meters. The both aquifer were widely polluted by nitrate. The nitrate concentration exceeded the environmental quality standard (10 mg N/l) in approximately 20 % of the wells studied. The nitrate might be derived principally from the agricultural materials such as chemical fertilizers and manures, which were used in farmland in the past. The nitrogen used in the farmland might directly enter the unconfined shallow groundwater beneath the farmland. On the other hand, the nitrogen in the confined deep groundwater below Misobeta member might be transported over a long distance from upper farmland.
環境アセスメント学会の論文
2006-08-10