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MGH-02 Groundwater - Geopollution, contamination and health aspects
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Natural attenuation, groundwater flow and groundwater quality of shallow aquifer on VOCs Geo-pollution site in Urabe district, northern part of shimousa upland, northern Boso Peninsula, central Japan
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Osamu Kazaoka, Research Institute of Environmental Geology, Chiba (Japan)
Mitihiro Murakoshi, Department of Citizen Economy (Japan)
Takashi Kusuda, Research Institute of Environmental Geology, Chiba (Japan)
Hisashi Nirei, The Society of Geo-pollution Control, Japan, NPO (Japan)
Takeshi Tanaka, Tanaka Environment Co., Inc. (Japan)
Katsuhiro Aoki, OYO Corporation (Japan)
Akiko Yamaki, Department of environmental life, Chiba Prefecture (Japan)
Mio Takeuchi, Institute for Geo-Resources and Environment, National Institute of Advanced Industrial Science and Technology (Japan)
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Groundwater pollution with VOCs, composed of PCE and DCE in this site, was fined from drinking water wells on Urabe district in small valley, northern part of the Shimousa upland. Hydro-geological stracture and VOCs distribution of subsurface ground-air, groundwater of each aquifer and strata were surveyed. The results are as follows. The geo-pollution site is composed of 8 aquifers and 8 aquicludes from surface to 60m depth. On geo-pollution source, dry cleaning factory, from 1st aquifer to 4th aquifer were polluted with high VOCs concentration. VOCs groundwater pollution plume have migrated in the 3rd aquifer, using mainly for drinking water wells, and the 4th aquifer. The high polluted strara were removed and filled in cement by Soil Replacement Technology. Polluted groundwater have been pumped up and treated in 3rd aquifer and 4th aquifer. Groundwater pollution plume of 2nd aquifer have migrated little because of slowly groundwater flow after taking out of main geo-pollution source. The concentrations of VOCs have decreased naturally.
Vertical distributions of groundwater quality with pH, Do and Ec were measured by bore hole multi-sensors in each observation well in 2nd aquifer. The results are as follows. Groundwater in 2nd aquifer migrate to northeastward in the western pollution site and migrate to northward in central pollution site. The groundwater contain high Do and low Ec in western pollution site, upper reaches. Then the groundwater in center pollution site, lower reaches, contain low Do and high Ec. These show as follows. The groundwater with high Do have been sank at western area and migrate to northeastward. Then O2 have been consumed and Ec increased. The oxidized groundwater change to deoxidized it and low Ec change to high Ec with migration. Groundwater pollution plume in 2nd aquifer have located in deoxidized part and have decreased VOCs concentration naturally.
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