Abstract

From May 1999 to July 2000, concentration of 17 metals (Al, Ba, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, Pb, Sr, V, Zn), 4 ions (<TEX>${NH_4}^+$</TEX>, <TEX>$Cl^-$</TEX>, <TEX>${NO_3}^-$</TEX>, <TEX>${SO_4}^{2-}$</TEX>) and pH in rainwater were investigated. The volume-weighted mean concentrations (VWM) of <TEX>${NO_3}^-$</TEX> and <TEX>${SO_4}^{2-}$</TEX> were 16.0 and <TEX>$17.0{\mu}mol\;L^{-1}$</TEX>. The average pH was 4.53, which ranged from 3.83 to 6.06. The characteristic variations of these species were investigated in terms of the source of these species by principal component analysis (PCA) and interelement correlation coefficients. The elements were classified into three categories: anthropogenic source (Cd, Cu, Fe, Ni, Pb, V, Zn, <TEX>${NH_4}^+$</TEX>, <TEX>${NO_3}^-$</TEX>, <TEX>${SO_4}^{2-}$</TEX> and <TEX>$H^+$</TEX>), soil and crust dust (Al, Ba, Ca, Fe, Mn) and sea salts (Mg, Na, <TEX>$Cl^-$</TEX>). In addition, we compared the concentrations in rainwater, which were taken on the same day in three sites (Higashi-Hiroshima, an urban-facing area and a mountain-facing area of Mt. Gokurakuji) in order to examine the regional effect against the concentrations in them. At the urban-facing area of Mt. Gokurakuji, the concentrations of chemical compositions were higher than other areas.