Conductivity

Conductivity: Measure of the ability of water to pass an electrical current.

Normal Measures for Conductivity:

• Studies of inland fresh waters indicate that streams supporting good mixed fisheries have a range between 150 and 500 μhos/cm. Conductivity outside this range could indicate that the water is not suitable for certain species of fish or macroinvertebrates.
• Freshwater streams ideally should have a conductivity between 150 to 500 µS/cm to support diverse aquatic life.

What affects conductivity?

• The presence of inorganic solids such as chloride, nitrate and sulfate.
• Organic compounds such as oil or alcohol do not conduct electricity well and therefore have a low conductivity.
  • When there’s an oil spill there will be low conductivity.
• Discharges to streams can change the conductivity depending on their make-up. A failing sewage system would raise the conductivity because of the presence of chloride, phosphate, and nitrate
• Climate change may increase the saltiness of freshwater lakes if warmer conditions increase evaporation.
• Pollution can also increase conductivity of lakes and rivers because industrial and human wastewaters often have high conductivity

Why is Conductivity important?

• Conductivity is an indirect measure of the saltiness of the water. Fish and other organisms that live in freshwater cannot tolerate large increases in the saltiness of the water because they will not be able to keep water in their bodies.
• It highly affects the animals in the water and can also give insight to what has been thrown into the river.

Conductivity data may not be accurate due to issues with the Vernier LabQuest probes. New equipment is being investigated for improved accuracy.