Data Set Interpretation

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Data Set Interpretation

• Susan Bolyard
• Hydrochemical Techniques

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• Ouachita Mountain Area
• Plotted dissolved ion and Cl concentration
  covariations to determine geochemical behavior
  patterns
• Cl ions do not participate in weathering
  reactions since local lithologies contain no
  evaporites. Therefore, Cl ionswould primarily
  come from human influence and are conservative
  throughout the hydrogeologic cycle.
• Cation/Anion Balance
• Ca vs. HCO3 and Ca Mg vs. HCO3

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Cl vs Na

• Many points fall above the seawater-dilution line
  (slope 2), indicating the Na content in these
  waters increases due to rock-water interactions
  related to silica weathering

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Cl vs. K

• Waters with low K concentrations tend to have
  varying Cl concentrations.
• If the K values are high, could indicate
  anthropic origin

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Cl vs. SO4

• Sulfate concentrations variable at Cl values lt 6.
  In the Ouachitas there is one location of
  possible evaporite-like rocks created by
  metamorphic activity. Increased values of SO4
  could be found in this environment (by Magnet
  Cove)

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Cl vs. NO3

• Nirate levels are defined by a linear trend with
  large variations. This could reflect
  agricultural practices or sewage effluent.
• The locations where NO3 values are 0 ppm and the
  Cl values read around 4ppm could indicate
  denitrification.

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Cation/Anion Balance

• Cations
• Na, Ca, Mg, K
• Anions
• Cl, SO4, NO3, HCO3
• A bit of a charge imbalance weighing heavy on the
  negative charge.
• Cation/Anion balance percent 7.5
• R2 value of 0.998

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Cl vs. Ca, Mg and HCO3
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Ca vs. HCO3

• Comparing Ca to HCO3, most of the data points are
  off of the CaHCO3 equivalent line. This would
  indicate an anion influence and inferring that
  another cation is necessary to reach a balance.

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Ca Mg vs HCO3

• Ca Mg plotted as a function of HCO3
• Points are better scattered around the 11 line