Abstract
This study was implemented to investigate the anion and cation concentrations of Miomotegawa river since it is one of the most important salmon rivers in Japan. A great number of salmons have returned to the river, and it was expected to contain relatively lower cation concentrations since granite is widely distributed in the river catchment area. The anion and cation concentrations of station 1 except $NH_4{^+}$ were higher than those of other stations. The concentrations of $Na^+,\;K^+,\;Mg^{2+},\;Ca^{2+}$, and $Cl^-$ at station 2 were 8.61, 1.06, 1.84, 4.47, and 14.5mg/l, respectively. In the case of $NH_4{^+},\;NO_3{^-}$ and ${SO_4}^{2-}$, they were 0.04, 2.99 and 5.31mg/l, respectively at station 2 of down stream. However, at station 5 of upstream, they were 0.01, 1.37 and 4.08mg/l, respectively, which were relatively lower than that of downstream.