Japan Geoscience Union Meeting 2015

Presentation information


Symbol A (Atmospheric and Hydrospheric Sciences) » A-HW Hydrology & Water Environment

[A-HW27] Water and material transport and cycle in watersheds: from headwater to coastal area

Sun. May 24, 2015 6:15 PM - 7:30 PM Convention Hall (2F)

Convener:*Shinji Nakaya(Department of Civil Engineering, Faculty of Engineering, Shinshu University), Mitsuyo Saito(Graduate School of Environmental and Life Science, Okayama University), Shin-ichi Onodera(Graduate School of Integrated and Arts Sciences, Hiroshima University), Kazuhisa Chikita(Department of Natural History Sciences, Faculty of Science, Hokkaido University), Tomohisa Irino(Faculty of Environmental Earth Science, Hokkaido University), Masahiro Kobayashi(Forestry and Forest Products Research Institute), Seiko Yoshikawa(Narional Institute for Agro-Environmental Sciences), Noboru Okuda(Research Institute for Humanity and Nature)

6:15 PM - 7:30 PM

[AHW27-P01] Transportation and precipitation characteristics of toxic element in river and its bottom sediment in Asama-yama area

*Mistunori ISHIKAWA1, Shinji NAKAYA1, Chi HAI1, Tomoko KUJIOKA1, Harue MASUDA2 (1.Shinshu University, 2.Osaka City University)

Keywords:toxic trace element, bottom sediment, river

Some toxic trace elements are often transported to agricultural land by some water system and move to bottom clayey soil by precipitation. Therefore, it is important issue on prevention of health hazards to clarify the mechanism for transportation, precipitation and concentration of toxic elements in a water system.
In this study, in order to clarify the mechanism for transportation, precipitation and concentration of toxic trace elements in a water system, river waters and bottom sediments were sampled at 18 points in a small river of Asama-yama volcanic mountain area. From the correlation between major elements and toxic trace elements, major attracter elements are found in a river. The following conclusions are obtained: 1) The toxic trace elements (Cu, Pb, Co, Sr) in bottom sediments are with compatible major attracter elements; K2O for (Cu,Pb), (T-Fe2O3) for Co, Al2O3 for Sr, 2) The toxic trace elements (Cu, Pb) in river waters are with compatible major attracter elements; (Al, Ti) coloid for (Cu, Pb), 3) No attractor for Sr in river water, 4) Fe-colloid is a attractor of (Al, Ti) in river water.
From the described above, it is modeled that first, (Cu,Pb) are transported by Fe-colloid, that is attractor of (Al,Ti), second, Fe-Al-Ti-colloid precipitate with (Cu, Pb), third, (Cu, Pb) are attracted by K2O, and move to bottom sediment, finally, Fe-Al-Ti-colloid released (Cu, Pb) moves from bottom sediment to river water. These processes are repeated, and (Cu, Pb) are move from water to bottom sediment. Co will move with Fe-colloid, because Fe-colloid is a compatible attractor of Co.