Abstract
During the period from Nov.1 to 30, 1984, pH, E.C. and concentrations of dissolved ions in rain waters at Mt. Ohdaigahara, a mountainous area, were measured.
The pH and E.C. of rain waters were in the range of 4.32 to 5.15 (mean value 4.67) and of 6.45 to 55.52 (mean value 14.79)μS/cm, respectively. The concentration of SO42-, NO3-, NH4+ and Ca2+ that were main ionic components in rain waters were 1.45, 0.53, 0.05 and 0.21 μg/ml, respectively.
The ionic components in the rain water at Mt. Ohdaigahara were nearly similar to that of the average succeeding rain water (6 mm-rainfall amount) in Nara city.
At Mt. Ohdaigahara, Cl-/Na+ (ratio of equivalent composition) in the rain water was closely resemble to that of sea water and the NH4+ concentration in the rain water was far low value compared to that in the urban areas.
The amount of deposits of NH4+, Ca2+ and NO3- components of dustfall were remarkably revealed in locational difference and those were considered to apply the index of mountainous areas.
