鉱物の化学的風化による酸中和能の流域比較

抄録

Acid deposition in eastern Asia will increase and exceed those encountered in northern Europe and northeastern USA. Consequently, freshwater in Japan is likely to become acidified. In order to predict the long-term acidification of freshwater, it is necessary to evaluate acid neutralization mechanisms operative in Japanese watersheds.
In this report, an estimation method for acid-neutralization by chemical weathering is proposed. This method is composed by quantifying input-output budgets, and estimation of chemical weathering reactions of minerals in watershed.Using this estimation method, acid-neutralization mechanism is compared between acidified and non-acidified watersheds.
By this comparison, acid deposition is neutralized in Japanese non-acidified watersheds by chemical weathering reactions of primary minerals. On the other hand, in acidified watershed in U. S. A., chemical weathering rates of primary minerals are much smaller than those in Japanese non-acidified watersheds, consequently acid deposition is not neutralized in this watershed. On the basis of comparison for chemical weathering rates and site descriptions of watersheds, it is estimated that chemical weathering rates in watersheds are effected by the depth of weathering layer and acid deposition.