2009-2014년 제주지역 강수의 이온조성 및 오염특성

The objective of this study was to determine the acidification of precipitation in the Jeju area. Precipitation samples were collected from the Jeju area from 2009-2014, and the major ionic species were analyzed. In the regression analysis, through a comparison of ion balance, electric conductivity, and acid fraction, the correlation coefficients showed a good linear relationship within the range of 0.927~0.983. The volumeweighted means of the pH and electric conductivity were 4.9 and 22.7 μS/cm, respectively. The ionic strength of precipitation was 0.27±0.38 mM, indicating about 35.9 % of total precipitation within the pure precipitation criteria. The volume-weighted mean concentrations (ieq/L) of the ionic species in the precipitation were in the order of Na+ > Cl− > nss-SO₄ 2− > NO₃− > NH₄+ > Mg 2+ > H+ > nss-Ca 2+ > PO₄ 3− > K+ > HCOO− > CH3COO−> NO₂− > F− > HCO₃− > CH₃SO₃−. The acidification contributions by sulfuric and nitric acids were 54.5 % and 36.5 %, respectively. Meanwhile the acidification contributions by formic and acetic acids were 4.8 % and 4.2 %, respectively. Thus, it was found that the acidification of the precipitation in the Jeju area was mainly due to the inorganic acids. The neutralization factors by NH3 and CaCO3 were also 33 % and 20 %, respectively.