Chemical Constituents of Rainfall at Different Locations on Oahu, Hawaii

摘要

Rainfall sampling, which began in 1981 before the 1982 to 1983 El Nino and continued into 1984 on Oahu in Hawaii, represented sites with widely different rainfall amounts. Samples stored under refrigeration prior to analysis were analyzed for pH and for the major cations, chloride and sulfate, and the nitrogen series. For the stored samples, the rainiest site was acidic with median pH 4.9, and rainfall weighted pH 4.77. Electrical conductivity of the rainfall was equivalent to cation concentrations of 1 to 10 milliequivalents per liter. Chloride, a major cation, decreased with distance from the ocean sources. Sulfate values in the rainwater increased during southerly flow when Kilauea volcano was erupting. The pH values of 4.2 to about 5.0 support the contention that the acidity in naturally occurring rainfall in remote areas has a pH slightly below 5.0.