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37,942,000 Yen
Acidification of the rivers and lakes by the acid deposition was checked in Japan. Buffering capacity of the watershed in 7 metamorphous belts is usually smaller than those in other watershed on the basic bed rock. Probability of acidification of rivers and lakes were checked by measuring alkalinity and other items of water quality. It was found that the mountain lakes, Sugoroku-ike and Washiba-ike in the Northern Alps of Japan, have catchment of almost no buffering capacity, where weakly acidic rain causes immediate acidification of the lake water. Almost all river waters measured, however, had alkalinity of more than 0.15 meq/1, which means that the probability of acidification of river water is very little in Japan.
Monitoring of the river and lake Waters was carried out in Nikko area of Tochigi Prefecture, Bibai area of Hokkaido Prefecture and Northern Alps area of Nagano Prefecture. Purpose of this periodical frequent measurement lasted for more than 2 months were to detect pH falls by the snowmelt acidic shock which had been shown to cause sometimes serious acidification in the beginning of snowmelt. A typical pH fall by snowmelt acidic shock was observed for 10 days in a small stream of Bibai area, but only once and any more after this. Geology of this catchment is characterized by the very thin soil layer on the unpenetrative clay. No sign of pH fall was detected in the other points selected above.
Acid deposition, Terrestrial, Acidification, Buffering capacity