Grant-in-Aid for Scientific Research (B).
|Section||Joint Research .|
|Research Institution||Miyazaki University|
YOKOTA Hiroshi MIYAZAKI UNIV.ENGINEERING, PROF., 工学部, 教授 (90037888)
AHMED M.F. バングラデシュ工科大学, 土木工学部, 教授
RAHMAN Md.H. バングラデシュラジャヒ大学, 地質鉱山学部, 教授
TANABE Kimiko MIYAZAKI UNIV., MATERIALS RESEARCH, LECTURER CENTER, 機器分析センター, 講師 (00179805)
AKIYOSHI Yosuhiro MIYAZAKI UNIV., AGURICALTURE, ASOC.PROF., 農学部, 助教授 (30041031)
SEZAKI Mitsuhiro MIYAZAKI UNIV., ENGINEERING, ASOC.PROF., 工学部, 助教授 (80136803)
広中 博見 福岡市・保健環境研究所, 主査
HIRONAKA Hiromi FUKUOKA CITY, RESEARCH CENTER FOR HEALTH
|Project Fiscal Year
1998 – 2000
Completed(Fiscal Year 2000)
|Budget Amount *help
¥7,000,000 (Direct Cost : ¥7,000,000)
Fiscal Year 2000 : ¥2,300,000 (Direct Cost : ¥2,300,000)
Fiscal Year 1999 : ¥2,100,000 (Direct Cost : ¥2,100,000)
Fiscal Year 1998 : ¥2,600,000 (Direct Cost : ¥2,600,000)
|Keywords||UNDERGROUND WATER / ARSENIC POLLUTION / DRINKING WATER / GANGES DELTA / GRAVEL-SAND FILTER / REDOX / MECHANISM OF ARSENIC POLLUTION / 地下水 / ヒ素汚染 / 飲料水 / ガンジスデルタ / 砂利・砂ろか / 酸化・還元 / ヒ素汚染の機構 / バングラデシュ / ボーリング / 礫間浄化 / ため池水 / 砒素汚染 / 浄水装置 / ため池 / 地下水砒素汚染|
1).It is considered that arsenic may be mainly released into groundwater from As-rich Fe oxyhydroxide in the ground under the condition of reduction in Samta village from the following new finding.
(1)Arsenic was highly included at peat bed in upper muddy layer.
(2)The distribution of upper muddy layer was in accordance with that of arsenic contamination of groundwater.
(3)Arsenic concentration was higher at the zone where the trivalent arsenic was detected more compared with the pentavalent arsenic, low arsenic concentration in the pentavalent srsenic zone.
(4)It was characteristic that HCO_3 and Fe^<2+> contents of groundwater were high and their distribution was in accordance with that of arsenic contamination.
(5)The high arsenic-contaminated zone of groundwater agrees well with the drifting zone of groundwater where the aquifer is more in the state of reduction in the zone.
2).Arsenic free water has been successfully obtained from Pond Sand Filter(PSF) as follows.
(1)The major cause of arsenic contamination of ponds was considered as inflow of surface drainage from arsenic-contaminated shallow tube wells and co-precipitation of arsenic with sediment grains in suspension in the pond water.
(2)It was observed that gravel filter tank, an altemative pre-treatment system, for sand filter tank, had the ability to decrease the turbidity and the number of bacteria of raw water efficiently.
(3)The PSF installed in Samta is working very well. PSF No.2, constructed February 2000 in a adjacent village, is now supplying good treated water, too.
(1)Numerical analyses for the advection and diffusion of arsenic in the groundwater.
(2)Application of PSF to removal of arsenic from tube well water.