The type of the water circulation of lakes is extremely different by each lake. It is, while there are lakes that the water is seldom exchanged, and there is some a distribution of the water as if like the river on intense lakes. Especially, it is lakes without the runoff river to receive the environmental pollution. "The closed lake" taken up in this study are lakes without inflow and runoff river, and it is lakes which is most easy to receive the environmental pollution superscription description way. Especially the drop acidic product has been made the cause of this pollution in lakes to be a problem than the direct and artificial pollution. Recently, seeing effect has produced that the forest does withering on stalk by acid rain and acidic mist, etc. the increase of the drop acidic product which becomes serious year by year begins to have also appeared in lakes. Especially, a snowfall for winters is stored in lakes in the region with the snow in all basins. This time, also drop aci
dic product simultaneously, basin. The acidic product in the basin flows into lakes with the spring snowmelt in short time. The acidic product in the basin flows into lakes with the spring snowmelt in short time. As this result, the acidity of lakes inside increases in the spring, and the serious effect in the ecosystem is brought about.
In this study, the continual observation was carried out in order to clarify which degree effect drop acidic product gives in water quality of Kirigome Lake and Karigome Lake, Goshiki-numa which is located in Nikko City in Tochigi Prefecture and Hokkaido Mashu Lake, lakes in Izu Islands Mikurajima. As a first step, water balance of quantity of water which flows into each lakes and quantity of water which escapes to each lakes escape was done. And, the spring water which was located around lakes was sampled, and snowfall and rainfall of the catchments were collected and were analyzed, while the water quality is analyzed. Like the above, the water balance of the blockage lake was analyzed, and the material balance of acidic product which in addition, flowed with this from the basin was done, and the buffering capacity of each lake was obtained.
Though as the result, the forest damage of the nearby region was also recognized either lakes , the acidification of the lake water body in this region at the 10〜20 unit could not be recognized. However, in the home, lakes put under the more serious environment are not few either, and the continual monitoring study seems to be indispensable. Less