Factors Affecting Ion Concentrations

Monitoring and Management‎ > ‎5. Water‎ > ‎

Identify factors that affect the concentrations of a range of ions in solution in natural bodies of water such as rivers and oceans

  • There are many factors that influence the concentration of various ions in a natural body of water:
    • Nature of rain:
      • Minerals present in the pathways from rain to the water body.
      • Solubilities of minerals present in these pathways.
      • Acidity of rain, as acid rain increases concentrations of certain ions (such as calcium, magnesium and iron) in the water body because it is better able to leach these from its pathway.
      • Rate at which rainwater enters the water body (high rate dilutes water).
    • Rate of evaporation from the water body.
    • Extent of human activities:
      • Extent of agricultural practices, such as the use of fertilisers, in areas near the water body.
      • Extent of discharge of waste from industry into the water body.
      • Extent of discharge of effluent into the water body.
      • Extent of leaching from rubbish dumps into the water body.
  • Due to their smaller volumes, rivers and dams are more susceptible than oceans to changes in ion concentrations.
  • However, ion concentration in coastal ocean water can be significantly affected, particularly by:
    • Discharge of sewerage.
    • Run-off from rivers that flow through agricultural land.