• Korean Journal of Environmental Agriculture
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• v.27 no.3
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• pp.239-244
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• 2008

To evaluate the acidity and chemical characteristics of rainwater in Korea, its pH and ion concentrations were investigated in Suwon from April to December, 2006. In addition, to estimate the contribution of ions on its acidity, ion composition and neutralization effect of major cations were investigated. Ion balance and electrical conductivity balance between measured and estimated values showed a high correlation. The mean pH and EC in rainwater collected during the investigation periods were 4.7 and $17.6{\mu}S\;cm^{-1}$, respectively. The monthly variation in EC showed a clear seasonal pattern, which had the lowest value of $9.1{\mu}S\;cm^{-1}$ in July and increased remarkably in November. $Na^+$ was the most abundant cation and followed by $NH_4{^+}>Ca^{2+}>H^+>Mg^{2+}>K^+$. Among them, $Na^+$ and $NH_4{^+}$ accounted for more than 65% of the total cations. In case of anions, the relative abundance was $SO_4{^{2-}}>NO_3{^-}>Cl^-$. About 67% of the total anions in rainwater was $SO_4{^{2-}}$, which showed $119.0{\mu}eq\;L^{-1}$ as mean value during the monitoring periods. Furthermore, 94% of the soluble sulfate in rainwater was identified as nss-$SO_4{^{2-}}$(non-sea salt sulfate). We also found that $NH_4{^+}$ and $Ca^{2+}$ contributed greatly in neutralizing the rain acidity, especially in dry season.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.5
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• pp.336-340
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• 2009

The issue of acid precipitation and related environmental problems in East Asia has been emerging. To evaluate the acidity and chemical characteristics of rainwater in Korea, its chemical properties during cultivation season from April to October were investigated at Taean in 2007. Also, to estimate the contribution of ions on its acidity, ion composition characteristics and neutralization effects by cation ions were determined. The ion balance between cations and anions values showed high correlation. The mean values of pH and EC were 4.9 and $32.9{\mu}S\;cm^{-1}$, respectively. The EC of rainwater showed seasonal characteristic, which was $91.4{\mu}S\;cm^{-1}$ with relatively low rainfall compared with other monitoring periods. $Na^+$ was the main cation followed by $NH_4{^+}$ > $Ca^{2+}$ > $H^{+}$ > $Mg^{2+}$ > $K^+$. Among these ions, $Na^{+}$ and $NH_4{^+}$ covered over 70% of total cations. In the case of anion, the order was $SO_4{^{2-}}$ > $NO_3{^-}$ > $Cl^{-}$. The mean value of sulfate, which is main anion component in the samples was $152.1{\mu}eq\;L^{-1}$. Also, 90% of soluble sulfate in rainwater was $nss-SO_4{^{2-}}$(non-sea salt sulfate). With fractional acidity and theoretical acidity of rainwater samples, $NH_4{^+}$ and $Ca^{2+}$ contributed greatly in neutralizing the rain acidity.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.5
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• pp.578-583
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• 2010

Acid rain and its problem to environment such as acid precipitation and environmental problems related to the air pollution in East Asia has been emerging. To evaluate the acidity and chemical characteristics of rainwater precipitated in western Korea, Suwon and Taean, its pH and ion concentrations were investigated during farming season (April to November) in 2009. Also, ion composition and cation-affected neutralization were determined to evaluate the contribution of cations on the acidity of rainwater. Ion and electrical conductivity between the measured and the estimated showed high correlation. The $Na^+$ in rainwater was the main cation followed by ${NH_4}^+>Ca^{2+}>H^+>Mg^{2+}>K^+$. Sum of $Na^+$ and ${NH_4}^+$ contents was over 65% of total cations contents. In the case of anions, the concentration was in order of ${SO_4}^{2-}>{NO_3}^->Cl^-$. The ${SO_4}^{2-}$ among anions in rainwater composed about 61%, which showed on average 130.2 ${\mu}eq\;L^{-1}$ and 121.3 ${\mu}eq\;L^{-1}$ during monitoring at Suwon and Taean, respectively. Also, 89.6 and 88.6% of soluble sulfate in rainwater at Suwon and Taean area was NSS-${SO_4}^{2-}$ (Non-Sea Salt sulfate). Especially, ${NH_4}^+$ and $Ca^{2+}$ contributed greatly in neutralizing the acid rain in dry season. Total nitrogen content flowed into soil from rain was around 1~2 kg $ha^{-1}$ in each month, but in July at Suwon, it reached 6 kg $ha^{-1}$ due to heavy rain (over 7.3 mm).

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.5
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• pp.386-390
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• 2013

Recently, special attention has been given to acid rain and its problem to environment such as acid precipitation and air pollution in East Asia. In the present study, rainwater samples were collected from Apr to Nov in 2012. The samples were chemically characterized for the assessment of emission sources. Suwon and Yeoju regions, typical agricultural areas in South Korea, were chosen for study sites. Ion composition and cation-affected neutralization were determined to evaluate the contribution of cations to the acidity of rainwater. Ion and electrical conductivity between the measured and the estimated showed high correlation. The cations observed in Suwon and Yeoju were $Na^+$ > $NH_4{^+}$ > $K^+$ > $Ca^{2+}$ > $Mg^{2+}$ > $H^+$ and $Na^+$ > $K^+$ > $NH_4{^+}$ > $Ca^{2+}$ > $Mg^{2+}=H^+$, respectively. The anions of all sites were $SO{_4}^{2-}$ > $NO_3{^-}$ > $Cl^-$. While the amounts of sulfate, one of the major dissolved components of rainwater, were 77.6 and 75.6 ueq $L^{-1}$ in Suwon and Yeoju, the ones of NSS-$SO{_4}^{2-}$ (Non-Sea Salt sulfate) were 83 and 82% in Suwon and Yeoju, respectively. The comparison of observed pH values ($pH_{obs}$) with the theoretical pH values ($pH_{the}$) showed that the neutralization of rain water considerably went along during the study periods. The highest amounts of rainfall throughout the year in Suwon and Yeoju were 572.3 and 484.6 mm in July, and its corresponding nitrogen loadings in Suwon and Yeoju were 5.28 and 3.50 kg $ha^{-1}$, respectively. The major ion contents for crop growth with $SO{_4}^{2-}$, $Ca^{2+}$, $K^+$ and $Mg^{2+}$ were 51.7, 5.2, 11.8 and 1.8 kg $ha^{-1}$ in Suwon and 34.2, 4.0, 4.2 and 1.1 kg $ha^{-1}$ in Yeoju.