제주시 지역 강수의 산성화 및 오염 특성 연구

Abstract

The collection of precipitation samples was made at Jeju area during 2015∼2016, and their major ionic components have been analyzed by ion chromatography. In the comparison of ion balance, electric conductivity, and acid fraction for the validation of analytical data, the correlation coefficients showed a good linear relationship within the range of 0.953∼0.991 During the study period, the volume-weighted mean pH and electric conductivity were 5.13 and 15.9 μS/cm respectively. The precipitation was weak acidic, showing high frequency of 43.8% in the range of pH 5.0-5.5. The ionic strength of precipitation was 0.2 ± 0.2 mM, indicating 44.5% of total precipitation within a pure precipitation criteria. The volume-weighted mean concentrations (μeq/L) of the ionic species in precipitation were in order of Cl^(-)>Na^(+)>NH_(4)^(+)>nss-SO_(4)^(2-)>NO_(3)^(-)>Mg^(2+)>nss-Ca^(2)>H^(+)>K^(+)>HCOO^(-)>CH_(3)COO^(-)>HCO_(3)^(-)>F^(-)>NO_(2)^(-)>CH_(3)SO_(3)^(-)>PO_(4)^(3-), The marine (Na^(+), Mg^(2+), Cl^(-)) and anthropogenic (NH_(4)^(+), nss-SO_(4)^(2-), NO_(3)^(-)) species have contributed to the total ionic components of precipitation samples by 52.6% and 33.6%, respectively. NO_(3)^(-) and nss-SO_(4)^(2-) concentrations showed a distinct seasonality with higher concentration in winter compared to summer. The concentrations of Na^(+), Cl^(-), Mg^(2+), nss-Ca^(2+) increased in winter. The acidity contributions by sulfuric and nitric acids were 47.1% and 42.2%, respectively. The neutralization factors by NH_(4)^(+) and nss-Ca^(2+) were 0.44 and 0.21, respectively. The correlation coefficients between Mg^(2+) and Cl^(-), Na^(+) and Cl^(-), NH_(4+) and nss-SO_(4)^(2-), NH_(4)^(+) and NO_(3)^(-), were 0.95, 1.00, 0.90, and 0.87, respectively. The clustered back trajectory analysis showed that the concentrations of precipitation components were relatively high when the air masses movede into Jeju Island from the China continent. On the other hand, their concentrations were lower when from the North Pacific Ocean.