[1] Univ Mysore, Dept Geol, Mysore 570006, Karnataka, India
[2] Univ Mysore, Dept Environm Sci, Mysore 570006, Karnataka, India
[3] Univ Mysore, Dept Chem, Mysore 570006, Karnataka, India
[4] Tokyo Inst Technol, Mat Struct Lab, Ctr Mat Design, Yokohama, Kanagawa 226, Japan