The population of river otter (Lutra lutra) has been declined most of the world due to hunting, habitat destruction and indirect or direct influences of eutrophication, acidification and toxic chemicals. This study is conducted to identify the population decline of river otter in Korea with relation to environmental pollution caused by accumulation of heavy and flared metals. The field survey was conducted during Jan~Dec, 2004 at a monthly basis by collecting spraints. A total of 228 spraints were collected and analysis was done by ICP-AES. The concentrations of fourteen metals (Cr, Zn, Cd, Pb, Ni, Fe, Co, Mn, Mg, Cu, Al, Ba Hg, As) have been determined. Annual concentrations of Cd $(1.38{mu}g;g^{-1}),;Zn;(599.06;{mu}g;g^{-1}),;Pb;(5.54;{mu}g;g^{-1})$ at Gucheon were higher than those of Yeonchocheon. Concentrations of $Cr;(5.01{mu}g;g^{-1}),;Ni;(1.91{mu}g;g^{-1}),;Co;(0.25{mu}g;g^{-1})$ were higher at Yeonchocheon. Most metals in winter were significantly increased (P<0.05) as season progressed from spring to winter. $Pb;(15.58{mu}g;g^{-1}),;Cu;(15.15{mu}g;g^{-1}),;a;Guchoen;and;Cr;(5.77{mu}g;g^{-1})$ at Yeonchocheon were high in the downstream of winter.