Origin and Geochemical Characteristics of Cave Water in Hwanseongul Cave; 환선굴 동굴수의 기원 및 지구화학적 특성

초록

We identified the origin of cave water and dissolved components using the geochemical characteristics of cave water in Hwanseongul Cave (natural monument) and evaluated the influence of agricultural activity on cave water quality. Cave water parameters were measured monthly at 20 sites in Hwanseongul Cave from November 2023 to September 2024, and the chemical compositions of cave water were analyzed. Water temperature, pH, and ORP did not differ significantly between sites, but there were substantial differences in EC values. The cave water was classified as Ca-HCO<inf>3</inf> type, and cave water quality was controlled mainly by precipitation, water-rock interactions, and agricultural activity. The background values of representative pollutants (Cl-, NO<inf>3</inf>-, and SO<inf>4</inf>2-) were estimated to be 5.1, 17.5, and 4.1 mg/L, respectively, and the influence of agricultural activity was evaluated using the frequency of levels higher than the background values. The cave streams on the eastern side of Hwanseongul Cave were most affected by agricultural activity, and the water droppings on the western side were affected temporarily by agricultural activity. Though ~55% of sites were affected by agricultural activity, the contamination of cave waters by agricultural activity is minor. However, the quality of cave water could deteriorate due to agricultural activity and the cave environment can also change, therefore, it is necessary to continuously evaluate the impact of agricultural activity. © 2024 The Korean Society of Engineering Geology.

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