title: Natural and anthropogenic sources and processes affecting water chemistry in two South Korean streams.
abstract: Acid mine drainage (AMD) in a watershed provides potential sources of pollutants for surface and subsurface waters that can deteriorate water quality. Between March and early August 2011, water samples were collected from two streams in South Korea, one dominantly draining a watershed with carbonate bedrock affected by coal mines and another draining a watershed with silicate bedrock and a relatively undisturbed catchment area. The objective of the study was to identify the sources and processes controlling water chemistry, which was dependent on bedrock and land use. In the Odae stream (OS), the stream in the silicate-dominated catchment, Ca, Na, and HCO3 were the dominant ions and total dissolved solids (TDS) was low (26.1-165 mg/L). In the Jijang stream (JS), in the carbonate-dominated watershed, TDS (224-434 mg/L) and ion concentrations were typically higher, and Ca and SO4 were the dominant ions due to carbonate weathering and oxidation of pyrite exposed at coal mines. Dual isotopic compositions of sulfate (δ(34)SSO4 and δ(18)OSO4) verified that the SO4 in JS is derived mainly from sulfide mineral oxidation in coal mines. Cl in JS was highest upstream and decreased progressively downstream, which implies that pollutants from recreational facilities in the uppermost part of the catchment are the major source governing Cl concentrations within the discharge basin. Dual isotopic compositions of nitrate (δ(15)NNO3 and δ(18)ONO3) indicated that NO3 in JS is attributable to nitrification of soil organic matter but that NO3 in OS is derived mostly from manure. Additionally, the contributions of potential anthropogenic sources to the two streams were estimated in more detail by using a plot of δ(34)SSO4 and δ(15)NNO3. This study suggests that the dual isotope approach for sulfate and nitrate is an excellent additional tool for elucidating the sources and processes controlling the water chemistry of streams draining watersheds having different lithologies and land-use patterns.
authors.affiliation: Division of Earth and Environmental Sciences, Korea Basic Science Institute, Cheongwon-gun, Chungbuk 363-883, Republic of Korea; Department of Geoscience, University of Calgary, Calgary, Alberta T2N 1N4, Canada.
authors.forename: Woo-Jin
authors.initials: WJ
authors.lastname: Shin
authors.affiliation: Division of Earth and Environmental Sciences, Korea Basic Science Institute, Cheongwon-gun, Chungbuk 363-883, Republic of Korea.
authors.forename: Jong-Sik
authors.initials: JS
authors.lastname: Ryu
authors.affiliation: Department of Geoscience, University of Calgary, Calgary, Alberta T2N 1N4, Canada.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Mayer
authors.affiliation: Division of Earth and Environmental Sciences, Korea Basic Science Institute, Cheongwon-gun, Chungbuk 363-883, Republic of Korea. Electronic address: kslee@kbsi.re.kr.
authors.forename: Kwang-Sik
authors.initials: KS
authors.lastname: Lee
authors.affiliation: Division of Earth and Environmental Sciences, Korea Basic Science Institute, Cheongwon-gun, Chungbuk 363-883, Republic of Korea; Department of Geology, Chungnam National University, Yuseong-gu, Daejeon 305-764, Republic of Korea.
authors.forename: Sin-Woo
authors.initials: SW
authors.lastname: Lee
mesh_terms: D004784:Environmental Monitoring; D008906:Mining; D056910:Republic of Korea; D045483:Rivers / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D014874:Water Pollutants, Chemical
keywords: Carbonate; Nitrate; Silicate; Stable isotopes; Sulfate