Chemical Composition of Rainwater in Saga City

Abstract

Rainwater was collected in Saga city from January to December, 1989 to determine pH and major ions: Na⁺, K, Ca²⁺ mg²⁺, NO₃^-, NO₂^-, NH₄⁺ and Zn²⁺. The pH values range from 4.00 to 5.90 with a volume weighted mean value of 5.01. The free acidity was derived both from sulfuric and nitric acids. The [SO₄^2-]nss and [Ca²⁺]nss were evaluated from the Nat concentration under the assumption that all of the Nat originated from sea salt. The amount of [SO₄^2-]nss and [NO₃^-] (eq dm-3) was lower within Saga city than other cities. As [SO₄^2-]s in rainwater of other cities is lower than that of Saga city, the difference between [SO₄^2-]nss+ [NO₃^-] and [Ca²⁺]nss+[NH₄] is somewhat lower that of other cities. Therefore pH of rainwater within Saga city is somewhate higher than that of other cities.