Abstract
Hydrogeochemistry data collected from three multi-level monitoring wells in a sandy alluvial aquifer located in the Keum River watershed, South Korea, are used in this study to evaluate groundwater chemistry change in relation to geologic controls of groundwater recharge, redox condition, water–rock interaction and contamination susceptibility. A silt layer at a depth of about 10 m is a hydrologic barrier which prohibits the continued downflow of groundwater and divides the groundwater into two distinct masses (i.e., shallow ‘oxic’ groundwater and deeper ‘sub-oxic’ groundwater) with different redox states and ion chemistry. Compared to ‘sub-oxic’ water, ‘oxic’ water has lower SiO2/(Na + K) and higher Ca, NO3 and SO4, indicating significant contamination from agrochemicals and manures. The higher Ca and NO3 but lower HCO3 concentrations in ‘oxic’ water result from lime dissolution and nitrification. In contrast, ‘sub-oxic’ water shows increased SiO2 and HCO3, suggesting the effect of water–rock interaction in the aquifer. Potential sources of cations are Na from albite, Mg from chlorite and illite, and K from illite. Vertical fluctuations of cationic composition in ‘sub-oxic’ water suggest heterogeneity of aquifer mineralogy with depth. Mineral stability calculations show that the chemistry of ‘oxic’ water plots in the kaolinite field, while that of ‘sub-oxic’ water plots in the Ca-montmorillonite field and near the kaolinite/montmorillonite equilibrium boundary. Concentrations of dissolved inorganic carbon (DIC) in ‘sub-oxic’ water are much higher than total alkalinity (HCO3 + CO3), suggesting that CO2 generated by redox reactions such as denitrification, iron reduction and sulfate reduction causes increasing DIC, which also affects the dissolution of silicate minerals in an aquifer free of carbonate minerals.
Similar content being viewed by others
References
Appelo CAJ, Postma D (1994) Geochemistry. Groundwater and Pollution, Balkema
Böhlke JK (2002) Groundwater recharge and agricultural contamination. Hydrogeol J 10:153–179
Brown CJ, Walter DA, Colabufo S (1999) Iron in the aquifer system of Suffolk county. USGS WRIR, New York, pp 99–4126
Cai WJ, Wang Y, Krest J, Moore WS (2003) The geochemistry of dissolved inorganic carbon in a surficial groundwater aquifer in North Inlet, South Carolina, and the carbon fluxed to the coastal ocean. Geochim Cosmochim Acta 67:631–639
Cey EE, Rudolph DL, Aravena R, Parkin G (1999) Role of the riparian zone in controlling the distribution and fate of agricultural nitrogen near a small steam in southern Ontario. J Contam Hydrol 37:45–67
Chae GT, Kim K, Yun ST, Kim KH, Kim SO, Choi BY, Kim HS, Rhee CW (2004) Hydrogeochemistry of alluvial groundwaters in an agricultural area: an implication for groundwater contamination susceptibility. Chemosphere 55:369–378
Chae GT, Yun ST, Mayer B, Choi BY, Kim KH, Kwon JS, Yun SY (2009) Hydrochemical and stable isotopic assessment of nitrate contamination in an alluvial aquifer underneath a riverside agricultural field. Agric Water Manag 96:1819–1827
Chapelle FH (2001) Ground-water Microbiology and Geochemistry. Wiley, New York
Choi WJ, Han GH, Lee SM, Lee GT, Yoon KS, Choi SM, Ro HM (2007) Impact of land-use types on nitrate concentration and δ15N in unconfined groundwater in rural areas of Korea. Agric Ecosys Environ 120:259–268
Choi BY, Yun ST, Mayer B, Chae GT, Kim KH, Kim K, Koh YK (2010) Identification of groundwater recharge sources and processes in a heterogeneous alluvial aquifer: results from multi-level monitoring of hydrochemistry and environmental isotopes in a riverside agricultural area in Korea. Hydrol Process 24:317–330
Choi BY, Yun ST, Mayer B, Kim KH (2011) Sources and biogeochemical behavior of nitrate and sulfate in an alluvial aquifer: hydrochemical and stable isotope approaches. Appl Geochem 26:1249–1260
Fisher RS, Ill WFM (1997) Hydrochemical evolution of sodium-sulfate and sodium-chloride groundwater beneath the northern chihuahuan desert, trans-pecos, Texas, USA. Hydrogeol J 5:4–16
Frankignoulle M, Bourge I, Wollast R (1996) Atmospheric CO2 fluxes in a highly polluted estuary (The Scheldt). Limnol Oceanogr 41:365–369
Jacobs TC, Gilliam JW (1985) Riparian losses of nitrate from agricultural drainage waters. J Environ Qual 14:472–478
Jalali M (2009) Geochemistry characterization of groundwater in an agricultural area of Razan, Hamadan, Iran. Environ Geol 56:1479–1488
Kaown D, Koh DC, Lee KK (2009) Effects of groundwater residence time and recharge rate on nitrate contamination deduced from δ18O, δD, 3H/3He and CFCs in a small agricultural area in Chuncheon, Korea. J Hydrol 366:101–111
Kim K (2003) Long-term disturbance of ground water chemistry following well installation. Ground Water 41:780–789
Kim K, Rajmohan N, Kim HJ, Hwang GS, Cho MJ (2004) Assessment of groundwater chemistry in a coastal region (Kunsan, Korea) having complex contaminant sources: a stoichiometric approach. Environ Geol 46:763–774
Kim K, Kim HJ, Choi BY, Kim SH, Park KH, Park E, Koh DC, Yun ST (2008) Fe and Mn levels regulated by agricultural activities in alluvial groundwaters underneath a flooded paddy field. Appl Geochem 23:44–57
Kim KH, Yun ST, Choi BY, Chae GT, Joo Y, Kim K, Kim HS (2009) Hydrochemical and multivariate statistical interpretations of spatial controls of nitrate concentrations in a shallow alluvial aquifer around oxbow lakes (Osong area, central Korea). J Contam Hydrol 107:114–127
Koh DC, Mayer B, Lee KS, Ko KS (2010) Land-use controls on sources and fate of nitrate in shallow groundwater of an agricultural area revealed by multiple environmental tracers. J Contam Hydrol 118:62–78
Langmuir D (1997) Aqueous Environmental Geochemistry. Prentice-Hall, New Jersey
Lee RW (1997) Effects of carbon dioxide variations in the unsaturated zone on water chemistry in a glacial-outwash aquifer. Appl Geochem 12:347–366
McMahon PB (2001) Aquifer/aquitard interfaces: mixing zones that enhance biogeochemical reactions. Hydrogeol J 9:34–43
MIFAFF (Ministry for Food, Agriculture, Forestry and Fisheries, Republic of Korea) (2009) Food, Agriculture, Forestry and Fisheries Statistical Yearbook. MIFAFF, 11-1541000-000079-10
Min JH, Yun ST, Kim K, Kim HS, Kim DJ (2003) Geologic controls on the chemical behavior of nitrate in riverside alluvial aquifers, Korea. Hydrol Process 17:1197–1211
Naik PK, Awasthi AK, Anand AVSS, Behera PN (2009) Hydrogeochemistry of the Koyna River basin, India. Environ Earth Sci 59:613–623
Oren O, Yechieli Y, Böhlke JK, Dody A (2004) Contamination of groundwater under cultivated fields in an arid environment, central Arava Valley, Israel. J Hydrol 290:312–328
Park YH, Doh SJ, Yun ST (2007) Geoelectrical resistivity sounding of riverside alluvial aquifer in an agricultural area at Buyeo, Geum River watershed, Korea: an application to groundwater contamination study. Environ Geol 53:849–859
Parkhurst DL (1995) User’s guide to PHREEQC: a computer model for speciation, reaction-path, advective-transport, and inverse geochemical calculation. U.S. Geological Survey, Water-Resources Investigation Report 95–4227
Puckett LJ, Cowdery TK (2002) Transport and fate of nitrate in a glacial outwash aquifer in relation to groundwater age, land use practices, and redox processes. J Environ Qual 31:782–796
Rodvang SJ, Mikalson DM, Ryan MC (2004) Changes in ground water quality in an irrigated area of southern Alberta. J Environ Qual 33:476–487
Schofield S, Jankowski J (2004) Hydrochemistry and isotopic composition of Na-HCO3-rich groundwaters from the Ballimore region, central New South Wales, Australia. Chem Geol 211:111–134
Timms W, Acworth RI (2002) Origin, lithology and weathering characterisitics of upper Tertiary-Quarternary clay aquitard units on the lower Murrubidgee alluvial fan. Aust J Earth Sci 49:525–537
USSL (US Salinity Laboratory Staff) (1954) Diagnosis and improvement of saline and alkali soils. US Department of Agriculture, Washington DC
Acknowledgments
This work was supported by a research fund (R01-2007-000-20964-0) from the Korea Science and Engineering Foundation (KOSEF). Prof. Rodney Grapes helped to improve early draft version of this manuscript. Constructive comments provided by anonymous reviewers helped to improve and clarify the manuscript.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Choi, BY., Yun, ST., Kim, KH. et al. Geologically controlled agricultural contamination and water–rock interaction in an alluvial aquifer: results from a hydrochemical study. Environ Earth Sci 68, 203–217 (2013). https://doi.org/10.1007/s12665-012-1731-y
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s12665-012-1731-y