Heavy metal concentration in water and soil of different ecological areas of Tyva Republic R.B. Chysyma, Ye. Ye. Bakhtina, V.L. Petukhov, G.N. Korotkova and M.L. Kochneva J. Phys. IV France, 107 (2003) 301-302 DOI: 10.1051/jp4:20030301