2009~2010년 제주지역 강우의 오염 특성 연구

Abstract

The collection of rainwater samples was made at Jeju area during 2009~2010, and the major ionic species were analyzed. In the comparison of ion balance, conductivity, and acid fraction for the validation of analytical data, the correlation coefficients showed a good linear relationship within the range of 0.966~0.990. The volume-weighted mean pH and electric conductivity were 4.9 and <TEX>$17.8{\mu}S/cm$</TEX>, respectively, at the Jeju area. The volume-weighted mean concentrations of ionic species in rainwater were in the order of <TEX>$Cl^-$</TEX> > <TEX>$Na^+$</TEX> > <TEX>$nss-SO_4{^{2-}}$</TEX> > <TEX>$NH_4{^+}$</TEX> > <TEX>$NO_3{^-}$</TEX> > <TEX>$Mg^{2+}$</TEX> > <TEX>$H^+$</TEX> > <TEX>$nss-Ca^{2+}$</TEX> > <TEX>$HCOO^-$</TEX> > <TEX>$K^+$</TEX> > <TEX>$PO_4{^{3-}}$</TEX> > <TEX>$CH_3COO^-$</TEX> > <TEX>$NO_2{^-}$</TEX> > <TEX>$F^-$</TEX> > <TEX>$HCO_3{^-}$</TEX> > <TEX>$CH_3SO_3{^-}$</TEX>. The ionic strength of rainwater was <TEX>$0.26{\pm}0.21$</TEX> mM during the study period. The composition ratios of ionic species were such as 50.1% for the marine sources (<TEX>$Na^+$</TEX>, <TEX>$Mg^{2+}$</TEX>, <TEX>$Cl^-$</TEX>), 30.9% for the anthropogenic sources (<TEX>$NH_4{^+}$</TEX>, <TEX>$nss-SO_4{^{2-}}$</TEX>, <TEX>$NO_3{^-}$</TEX>), and 4.7% for the soil source (<TEX>$nss-Ca^{2+}$</TEX>), and 3.1% for organic acids (<TEX>$HCOO^-$</TEX>, <TEX>$CH_3COO^-$</TEX>). From the seasonal comparison, the concentrations of <TEX>$NO_3{^-}$</TEX>, <TEX>$nss-Ca^{2+}$</TEX>, and <TEX>$nss-SO_4{^{2-}}$</TEX> increased in winter and spring seasons, indicating a reasonable possibility of long range transport from Asia continent. Especially, the acidifying contributions by major inorganic acids (<TEX>$nss-SO_4{^{2-}}$</TEX> and <TEX>$NO_3{^-}$</TEX>) and organic acids (<TEX>$HCOO^-$</TEX> and <TEX>$CH_3COO^-$</TEX>) were 87.6% and 12.4%, respectively. In comparison by sectional inflow pathway of air mass during the rainy sampling days, the concentrations of <TEX>$nss-SO_4{^{2-}}$</TEX> and <TEX>$NO_3{^-}$</TEX> were relatively high when the air mass was moved from the China continent into Jeju area.