Abstract
The pH value and electric conductance (EC) of precipitation were measured in the Chichibu Mountains (Ootaki) and Kanto plain (Yorii) in Saitama Prefecture for 8 years from 1989 to 1996. These data were compared with those of an urban area (Urawa). The average pH values of Ootaki, Yorii and Urawa for 8 years were 5.08, 4.47 and 4.53, respectively. The average EC values were 10.3, 21.3 and 24.1μS/cm, respectively. The average concentration of Cl^- in precipitation from 1990 to 1991 were 0.32, 0.75, 0.73mg/L, NO^-_3 were 0.79, 1.74, 1.99mg/L, SO^<2->_4 0.80, 1.65, 2.34mg/L, respectively. The precipitation of Ootaki was cleaner than that of Yorii and Urawa. The fact that there was no difference in the pH and EC values of precipitation between Yorii and Urawa supported the assumption that air pollutants were transported from Tokyo Bay to Yorii by the air stream. On the other hand, there are no sources of air pollutants in Ootaki, but some air pollutants were transported from Tokyo Bay. As a result, Ootaki was a background area of precipitation with few pollutants.
