<論文>北海道西部における雨水中の化学成分の沈着量変化

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Precipitation samples were collected at Sapporo and at Mt. Haruka during the period from February 1998 to September 2000. These samples were filtered through a membrane filter (0.45μm porosity) and preserved at 4 ℃ in a refrigerator. Anions (Cl^-, NO_3^- and SO_4^<2->) and cations (Na^+, Mg^<2+>, Ca^<2+> NH_4^+ and K^+) in the samples were analyzed by using an ion chromatograph. Annual mean pH value at Sapporo station changed from 5.35 to 5.06. Therefore, it was pointed out that the rain water of Sapporo was not heavily polluted with acidic substances. The deposition of sodium, chloride and magnesium increased in Winter to Spring. The equivalent concentration ratio of Cl^-/Na^+ and Mg^<2+>/Na^+ in the Sapporo rain water were nearly equal to those in sea water, respectively. Thus, a large amount of sea salt is transported to Sapporo during the northwestern winter monsoon season, then removed as wet deposition. Non - sea - salt (nss) sulfate, nitrate and ammonium originated from man-made air pollutants were shown the different at Sapporo. Nss sulfate was incorporated in the cloud (rain out) over Asia continent or Japan Sea. Nitrate and ammonium were incorporated into the rain (wash out) over Sapporo.
北海道東海大学の論文
2000-03-25