Abstract
Chemical compositions of precipitation were measured at six sampling points in Toyama prefecter in the Hokuriku district during the piriod from April 1987 to March 1988. And pH, EC and concentrations of eight dissolved ions were measured and the property of the precipitation was investigated. The pH and EC of precipitations were in the range of 4.51 to 4.75 and 9.77 to 40.13μs/cm, respectively. The maximam frequencies of pH in the precipitation of the six sampling points concentrated at 4.4 to 5.0. On the assumption that the acid deposition was defined by the precipitation with a pH of less than 5.6, 70-90% of the precipitation were found to be the acid deposition. The dissolved ions in precipitation were consisted of six cations and three anions. The concentration of six cations and three anions in the precipitation were 43.5-280. 1 and 43.3-263. 3μeq/l, respectively. Ratios of equivalent composition of Cl^-/Na^+ in the precipitation was resemble to that of sea water. Contribution of sea salt to the dessolved ions in precipitation at coastal, urban and inland region. Annual amount of dopositions of SO_4^<2->, Cl^-, Mg^+ and Na^+ components were remarkablly revealed in regional difference. The amount of depositions of those decreased according to inland mountainous region from urban region.
