Estimation for Acidification in Land Water Environment based on Neutralization of Acidic Precipitation by Soil-Analysis by Mass Transfer Theory in three phases ; gas, liquid and solid-

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A phenomenon in which air pollutants emitted by burning fossil fuels including coal and petroleum undergo various exidation reactions in the atmosphere, producing sulfate and nitrate ions, and rainfall, snowfall and dry particulates strongly acidified by those ions fall on the earth is called "acid rain" or "acid snow" . Problesms of this phenomenon include acidification of precipitation caused by those air pollutants rather than their own toxicity. To evaluate the damage of ecosystems and buildings on the ground caused by the acidic precipitation, its acidity should be actively taken into account.In order to study a ecotechnological countermeasurement of acidic precipitaion, this research elucidates the mechanism of the neutralization of the precipitation with soil, focusing on the difference in pH between the precipitation and the water of rivers and lakes.The experiments were carried out by using a batch reactor of a cylindrial policarbonate vessel with a reaction volume of acidic s … More olution 250 ml and a column reactor with a dry soil weight of 50g. Nitric acid solutions adjusted to pH4 were prepared as the acidic solution.We obtained following results.(1) The results suggests that soil neutralize hardly acidic precipitation containing much cations. It is well known that heavy snow which contains much reasalts derived from Japan Sea covers on the Japan Sea side of Japan in winter. Therefore, we are worried the bad influence of melting snow in early spring in Japan Sea side of Japan on the quality of land waters.(2) It was found according to the column experiments that the soil neutralization ability do not only detriorate but also is able to recover.(3) The effects of carbon dioxide on neutralizaiton process of acidic precipitation with soil have been also investigated. In order to estimate the contribution of cabon dioxide contained in soil on the neutralization, column experiments were carried out under high concentration of carbon dioxide. The life of neutralization ability of soil in the column under high concentration of carbon dioxide was shorter than normal columns. Less