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Why test for electrical conductivity?

Electrical conductivity is used as an indirect measure of salinity. The greater the concentration of salt in water, the better it conducts electricity. By measuring electrical conductivity, we can infer the salinity of the water.

Salts occur naturally in the environment and are released through geological processes such as weathering of rocks. Salts are highly soluble. When salts are dissolved in water they are able to move and concentrate in the environment. Generally speaking, salinity increases as water evaporates or moves down through a catchment.

Salinity can be a major factor in determining the plant and animal species occurring in an aquatic environment. Changes in salinity can adversely affect the composition of freshwater communities.

Large and rapid changes in salinity are usually the result of human activities. Increases in the salinity of fresh water can result from:

  •  land clearing or chopping down trees
  •  excess watering of farm crops
  •  industrial discharge
  •  mining activities
  •  sewage discharge.