抄録
Effect of acidic deposition caused by the combustion of fossil fuel on surface waters has become significant in the United States and European countries since 1960s. On the other hand, the surface water acidification due to atmospheric pollutants has not yet been observed in Japan. For the long-term prediction of acidic deposition effect in Japan, an appropriate predictive method is neccessary. Comparison of acidified rivers and lakes in the United States and Europe, and surface waters in Japan, shows that the pH level of precipitation is higher and the acid neutralizing capacity (ANC) of watershed soil is larger in Japan than in these countries. Therefore, the acidic deposition effect in Japan should be predicted using a numerical model which takes into account the ANC of the watershed reasonably. From a viewpoint of reliability and applicability, four previous models: ETD, MAGIC, Birkenes and ILWAS are noted. However, these models may need verifications or modifications on their runoff components and mineral weathering submodels in their applications to Japanese watersheds, where geomorphological and geological conditions are different from those in the United States and Europe.
