본 연구의 목적은 전라남도 완도군 고금도 지역 지하수의 수리지구화학과 수소-산소동위원소를 파악하여 해수침투경로와 오염여부를 규명하는데 있다. 연구지역 지하수의 물리적인 특성은 중성과 전이환경에 속하며, 해수와 지표수의 영향을 받은 것으로 나타났다. 화학적인 특성에서도 해수의 침투, 육상의 오 · 폐수 및 농약이나 폐기물에 의해 오염이 진행되고 있다. 특히 지하수 중 여섯 지역에서 Cl은 먹는 샘물 기준치를 초과하는 것으로 나타났다. 파이퍼도에서 GG-4와 14지역은 해수의 침투로 오염되었으며, 수질유형을 구분하여 보면 GG-3, 7 및 13지역은 Na와 HCO3가 지배적이고, GG-14지역은 해수와 같이 Na와 Cl이 지배적으로 나타났다. 수리지구화학적인 모델링 분석결과 해수의 방해석과 백운석 포화지수는 과포화상태이며, GG-3, 14 및 18지역에서 포화영역에 접근하고 있다. 수소-산소동위원소비에서 본 역 지하수의 기원은 순환수이며, GG-1, 5 및 14지역의 높은 산소동위원소는 지표수의 유입과 해수 침투에 의한 것이다. 본 연구결과 GG-14지역의 지하수는 해수의 침투에 의해 오염되어 있으며, GG-3, 7 및 13지역을 제외한 지하수들은 해수의 침투 및 인위적인 오염원에 의해 오염이 진행되고 있다.
This study was performed to provide the basic information on characteristics of groundwater pollution in Gyeongsan city. Forty two groundwater samples were collected, and pH, DO, COD, NH3-N, NO3--N, T-N, PO43--P, Cl, Ca, Mg, hardness, evaporate residues and others were investigated. And, ANOVA analyses were carried out to reveal the differences in water pollution indicator values of by industry, commerce/residence and agriculture areas. The results were as follows.
1. The mean values of pH, DO, COD, NH3-N, NO3--N, T-N, PO43--P, Cl, evaporate residues, Ca and hardness were 6.9, 7.9 ㎎/ℓ, 0.4 ㎎/ℓ, 2.44 ㎎/ℓ, 2.73 ㎎/ℓ, 6.06 ㎎/ℓ, 0.82 ㎎/ℓ, 32.72 ㎎/ℓ, 381.67 ㎎/ℓ, 41.53 ㎎/ℓ, 177.17 ㎎/ℓ, respectively.
2. As groundwater became deeper, the values of Cl, Ca, Mg, Na, hardness and evaporate residues remarkably increased, but those of COD, NH3-N, NO3--N, NO2--N, T-N decreased. 3. The values of COD, Cl, Ca, Mg, Na, hardness and evaporate residues were very high in industrial area, and those of NH3-N, NO2--N, T-N were very high in commercial/residential area, and those of NO3--N were a little high in agricultural area.
4. The correlations between depth and each value of Mg, Na, Fe, hardness and evaporate residues were highly positive, and those between DO and each value of Mg, Cu, Fe, hardness and evaporate residues were highly negative.
5. According to ANOVA analyses, the differences in three area groups (industry, commerce/residence and agriculture) on the values of NH3-N, T-N, evaporate residues, hardness, Ca, Mg, K and Fe were significant at 1% level.
The pollution characteristics of groundwaters in Taegu City and correlation coefficients(r) between water pollution indicators were investigated for two years from January 1996 to December 1997.
Volatile organic compounds such as TCE(tri-chloroethylene), PCE(tetrachloroethylene), 1,1,1-trichloroethane, THM(trihalo-methane), dichloromethane, pesticides such as diazinon, parathion, malathion, and toxic inoganic matters such as As, Hg, Se, Pb, Cd, Cr6+ , CN were not detected in the groundwaters.
Mean values of groundwater pollution indicators were below drinking-water standards, but hardness, KMnO4-C(potassium permanganate consumption), evaporate residues, SO4-2, Fe, NO3- -N, color and turbidity exceeded a little in some samples. As groundwater became deeper, hardness and evaporate residues remarkably increased, but KMnO4-C, NO3- -N, Cl-, color, turbity and bacteria decreased. KMnO4-C, evaporate residues, Cl- and SO4-2 were very high at industrial and commercial areas, and NO3- -N and NH4+-N were very high at agricultural and forest areas.
It showed high positive significances in the relationships between hardness and each of evaporate residues, SO4-2, Zn and Mn, KMnO4-C and each of color, turbidity and Zn, color and each of turbidity, Cu, Zn and Mn, turbidity and each of Fe, Cu, Zn and Mn, and evaporate residues and each of Cl-, SO4-2 and Zn.