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Conductivity

Conductivity measures the water’s ability to conduct electricity which also indicates what is dissolved in water. Conductivity testing is often conducted to obtain data on ionic concentrations, including dissolved compounds in aqueous solutions. Common applications include water purification and measuring concentration amounts in solutions.

How Does Conductivity Affect Water Quality?

As conductivity is the measurement of water's ability to pass an electrical current, conductivity also indicates dissolved salts and inorganic chemical levels. Conductivity also increases as salinity increases. Overall, such measurements indicate water quality.

How Do You Measure Conductivity in Water?

Specific Conductance (SC) is a measure of how well water can conduct an electrical current. Conductivity increases with the increasing amount and mobility of ions. These ions, which come from the breakdown of compounds, conduct electricity because they are negatively or positively charged when dissolved in water.

Conductivity Water Quality Sensor Monitor

Conductivity Point-To-Point Sensor

The Waka includes a point-to-point conductive probe featuring two electrodes positioned opposite each other, with good sensitivity sensing. This sensor uses an alternating voltage applied to the electrodes and generates a current in the medium. The current’s intensity depends on the number of free anions and cations moving between the electrodes.

Conductivity Toroidal Sensor

Another option includes upgrading to the toroidal sensor, which is often used for dirty water like sewage treatment plants. As the sensor is robust and used in often unclean waters, it can get covered in gunge and seaweed yet still operate. This option contains a transmission and a reception coil which measures conductivity in a few steps.

Conductivity

  1. A circuit that produces a continuous, alternating waveform generates an alternating magnetic field in the transmission coil.

  2. The transmission coil’s alternating magnetic field induces a voltage in the medium.

  3. The medium’s cations and anions move and generate an alternating current.

  4. The alternating current produces a current to flow in the reception coil.

  5. The current’s intensity and conductivity increase with the number of free ions in the medium.

Why is Conductivity a Useful Measure of Water Quality?

Conductivity is useful for measuring water quality. As each water body tends to have a somewhat constant range of conductivity, upon establishing that, it can be used as a baseline for comparing with standard and regular conductivity measurements.

Human disturbance can increase the amount of Total Suspended Solids (TSS) and Total Dissolved Solids (TDS) entering waters, resulting in increased conductivity. Water bodies with elevated or even increasing conductivity may have other impaired, altered indicators as well.


How Do Conductivity Changes Indicate Poor Water Quality?

Much like what causes conductivity changes, such changes can indicate changes in water quality. Increased conductivity can mean water quality is decreasing due to pollution.

Salinity

Conductivity and salinity have a strong correlation, but as conductivity is easier to measure, algorithms estimate salinity, SS and TDS, which affect water quality and aquatic life.

Total Dissolved Solids

Water with a high TDS concentration can cause cells to shrink. Such changes can affect organisms’ ability to move in water and cause them to float or sink beyond their normal range.

Temperature

Conductivity is also affected by temperature, so the warmer the water, the higher the conductivity.

Salinity

Conductivity and salinity have a strong correlation, but as conductivity is easier to measure, algorithms estimate salinity, SS and TDS, which affect water quality and aquatic life.

How Monitoring Conductivity Can Help Protect Water Quality

The conductivity of water is important because it can tell you how many dissolved substances like TSS, TDS, chemicals, and other minerals are present in water. When conductivity increases, it indicates higher amounts of impurities and signals that something is degrading water quality and that the water is not safe.

New Zealand Environmental Water Quality Monitoring with Real Time Io T Artificial Intelligence Water Monitor RW

Conductivity, TSS and TDS Water Updates

The RiverWatch blog is the data centre for New Zealanders committed to monitoring and enhancing our waterways. Learn more about the water quality of New Zealand and our integral connection with the waters, and stay up to date with important news, research and developments.