| Research Abstract |
(1) Pollutants in rainwater are ascribed to several groups such as sea salt, soil, and so on. In this project, a factor analysis applicable to precipitation data, which accounts chemical equilibria, was developed in order to extract pollutant sources. A method of numerical evaluation of the contribution of the extracted sources was also developed.
(2) During 1995 to 1997, precipitations were collected at the Hyogo University of Teacher Education (HUTE) and at the Akita University ; and their chemical compositions were analyzed. The factor analysis applied to these two data sets demonstrated the difference of the pollutant sources.
(3) In order to know the geographical difference of the chemical composition in small area, the precipitations were collected (A) at seven places around the HUTE.Similar studies were carried out (B) in Akoh city of Hyogo facing to the Seto Inland Sea, and (C) around the Biwa Lake Bridge of Siga Prefecture. The geographical deviations of the concentration of nitrate ion and sulfate ion were small, but that of calcium ion was large. Unusuallarge evolution of magnesium ion was found at a place in Akoh-city.
(4) The separation collector of rainwater and the automatic recorder of atmospheric pressure, temperature, and precipitation amount were developed. The meteorological difference such as shower, low pressure, and front gave the different levels of concentration of ion. As increasing the amount of precipitation, the concentration of pollutant ion decreases.
(5) In evaluating acidity from pH value measured by the glass electrode method, pretty large errors were observed for the precipitations of low ionic strength. The errors were ascribed to the generation of liquid junction potential at the junction of the reference electrode. The high-precision micro-titrator was invented to evaluate the exact acidity ; and the mechanism of the generation of this junction potential was examined.
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