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Conductivity
(Adapted from The Streamwatch Manual – 3rd Edition)
Definition
Conductivity is an indirect method of measuring salinity and includes the measurement of all salts and organic acids.
Why test conductivity?
Salt is present naturally in freshwater creeks but if the concentration of salts is too high, aquatic macroinvertebrates will have difficulty keeping water inside them, and will shrivel and die. Adverse impacts are likely to occur in freshwater when salt concentrations reach 1500µS/cm.
Salinity can develop naturally, but human disturbance accelerates the movement of salts into creeks. Some causes of salinity include land clearing, irrigation, industrial and sewage effluent discharge, and tidal influx.
Equipment
- ECScan conductivity meter
- Liquid waste container
- Sample container
- Distilled water
- Recording sheets
Method
Note: Ensure the conductivity meter is calibrated before use otherwise results will not be accurate.
- Rinse electrodes with sample water over the liquid waste container three times before use.
- Half fill the sample container with creek water.
- Hold the meter in the water, swirling occasionally, until the reading stabilises and press the “hold” button.
- Record the result shown on the display on the recording sheets.
- Rinse the electrodes with distilled water.
- Discard of sample water back into the creek.
Updated: 04 Jan 2012