バングラデシュにおけるヒ素地下水汚染の地質的問題(アジア地下水ヒ素汚染問題を考える)

概要

論文の詳細を見る
Bangladesh faces the Bay of Bengal and its most territory comprises the Bengal Lowland. The Bengal Lowland is located in the lowest reaches of the Ganges and Brahmaputra-Jamna rivers. The Bengal Lowland is subdivided into Ganges Delta, Brahmaputra-Jamna river flood plain, and Sylhet Basin (Umitsu 1987). The land forms of the lowland consist of Pleistocene uplands and Recent alluvial lowlands. The recent sediments in the lowland are subdivided into five members by Umitsu (1987); namely lowest, lower, middle, upper, and uppermost members. The lowest member in the Bengal Lowland consists of gravel bed with the thickness of about 10 m. The lower member consists of the sandy sediments with scattered gravels. The sediments of the middle member are fine in their lower horizon and become coarser in the middle and upper horizons. There is an unconformity between the lower member and the middle member. The sediments of the upper member are fine in the lower and upper horizons and coarse in the middle horizon. The uppermost member is characterized by the fine sediments of silt or clay with peat. The author estimates that the lowest and lower members of the recent sediments form a main aquifer in the Ganges Delta. In Khluna district, the groundwater in the main aquifer may be under confined conditions. The groundwater monitoring data of the main aquifer at Jessore show that the groundwater levels tend to have been declined since 1990. The changes in groundwater level are characterized by sharp decline in dry season. This may indicate that the ground-water pumpage in dry season has been increased as well as the groundwater recharge from rain and river through the confining layers has been decreased.
地学団体研究会の論文
1997-11-07

バングラデシュにおけるヒ素地下水汚染の地質的問題(アジア地下水ヒ素汚染問題を考える)

スポンサーリンク

概要

著者

関連論文

スポンサーリンク