A Study of Chemical Composition of Precipitation and Element Budget at Two Small Watersheds in Beijing and Tokyo Suburbs
1999 Volume 60 Issue 2 Pages 185-200
Details
1999 Volume 60 Issue 2 Pages 185-200
The present studies were carried out in order to explore the current status of air pollution, chemical composition of precipitation, and element budgets at two small watersheds of Shisanling, Beijing suburb and Hakyuchi, Tokyo suburb, during June 1995-May 1996.
The results showed that annual average pH values of rainfall were 6.7 at Shisanling and 4.7 at Hakyuchi, and that the chemical compositions of precipitation were different between Shisanling and Hakyuchi. The concentration of sulphate was 325μeq l-1, which alone contributed over 70% to the anion total at Shisanling, while the concentration of nitrate was 46.5μeq l-1, which accounted for 38% of the anion total at Hakyuchi. This status indicated that air pollution was classified as sulphuric and nitric acid types, respectively. Concerning the element budget at the Shisanling watershed, total ions (F-, Cl-, NO2--N, NO3--N, SO42--S, Na+, K+, Ca2+, Mg2+, H+, NH4+-N) accumulated, but at the Hakyuchi watershed, Na+, Mg2+ and F- were discharged, and other ions such as SO42--S, NO3--N, Cl-, K+, Ca2+ and NH4+-N accumulated. The F- budget was remarkably different ; about 81% of the input accumulated at Shisanling, and 105% of the input was discharged at Hakyuchi. F- should significantly higher toxicity to plants than that of other acidic substances. If F- deposition remains at the recent level in Shisanling area continually, there will be possible future on the effects ecosystem.
