抄録
In order to assess the contribution of acid precipitation on water quality of river and lake, the results obtained by batch experiments were analyzed based on chemical equilibrium technique. In this study, four soils collected in Ishikawa Pref. were mixed with an acid solution at various pH. All of the soils contained little carbonates. Sulfate ion was not adsorbed on the soils except one soil sample. It was recognized that cation-exchange and dissolution of aluminum from the soils principally contributed to neutralization of acid precipitation by soils. The amounts of H+ ion replaced by exchangeable cations in soil, ΔH+, were estimated from the pH value of an acid solution before and after equilibration with soils. From the relationship between values of ΔH+ and concentrations of cations released from the soil, it was found that the soil contained some neutral salts. It was suggested that the existence of neutral salts in soils might give overestimates for the value of base saturation of soil. Since the obtained values of ΔH+ approximately agreed with sum of cation released from the soil samples, measurement of ΔH+ was believed to be simple and useful method to estimate total amounts of exchanged cations.
