下総台地における6価クロム地下水汚染機構

概要

論文の詳細を見る
The manufacturing plant located on the Shimofusa Plateau has made a subsurface permeation of waste water containing a large quantity of Cr^<6+> during the years from 1965 to 1971. In March, 1981, it was observed that a well water of a house on the west to this plant turned yellow due to Cr^<6+>. The deposits at depths of less than 60 m in this region consist of the highest horizon of the Shimofusa group, the Joso clay bed, the Kanto loam formation, and surface soil in ascending order. The perched water exints in the sediments above the Joso clay. There are three aquifers in highest horizon of the Shimofusa group. The upper one is unconfined aquifer and the lower two are confined aquifers. The mechanism of this groundwater pollution is as follows. The waste water containing Cr^<6+> stored in two pits descended vertically from the two pits to the perched water zone through the Kanto loam formation. As a flow of perched water this Cr^<6+> moved southward and descended to unconfined aquifer in the region where the Joso clay bed thined out. In addifion, Cr^<6+> descended to unconfined aquined aquifer moved to north-west as a flow of ground water of the unconfiend aquifer. Moreover, a portion of Cr^<6+> in the unconfiend aquifer moved to confined aquifer just below, as the leakage of groundwater.
日本地質学会の論文
1983-12-25