****[](https://archive.epa.gov/water/archive/web/html/vms59.html)**Conductivity of Water and Community Science**

A Wiki on Conductivity-Sensing is available on the Public Lab Website: https://publiclab.org/wiki/conductivity_sensing 

[ Photo Credit:  Stephen Gray estudiosdelafisica  ]

Historical contributors to electrical conductivity theory include:

Stephen Gray (1666-1736) http://www.sparkmuseum.com/BOOK_GRAY.HTM 
Benjamin Franklin (1706-1790) 
Alessandro Volta (1745-1827)     
George Simon Ohm (1787- 1854)
André Marie Ampère (1775-1836)
Sir Joseph John Thompson (1856-1940)
http://science.jrank.org/pages/2321/Electrical-Conductivity-History.html 

According to the [U.S. EPA archive,](null) "**Conductivity is a measure of the ability of water to pass an electrical current. ****Conductivity in water is affected by the presence of inorganic dissolved solids such as chloride, nitrate, sulfate, and phosphate anions (ions that carry a negative charge) or sodium, magnesium, calcium, iron, and aluminum cations (ions that carry a positive charge). Organic compounds like oil, phenol, alcohol, and sugar do not conduct electrical current very well and therefore have a low conductivity when in water. Conductivity is also affected by temperature: the warmer the water, the higher the conductivity. For this reason, conductivity is reported as conductivity at 25 degrees Celsius (25 C)...**.The basic unit of measurement of conductivity is the mho or siemens. Conductivity is measured in micromhos per centimeter (µmhos/cm) or microsiemens per centimeter (µs/cm). **Distilled water has a conductivity in the range of 0.5 to 3 µmhos/cm. The conductivity of rivers in the United States generally ranges from 50 to 1500 µmhos/cm. **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.** Industrial waters can range as high as 10,000 µmhos/cm."

**The Community Science Institute (CSI) initiated a community science volunteer program, referred to as Red Flag Monitoring **http://www.communityscience.org/volunteer/red-flag-monitoring/ 
along New York's Catatonk Creek and Cayuta Creek. **"Red Flag volunteers test for five parameters: Temperature, pH, Dissolved Oxygen, Conductivity and Total Hardness.** Conductivity and Total Hardness are specifically geared towards picking up impacts from shale gas waste. Conductivity is a measure of water’s ability to conduct electricity and is an excellent indicator for brine waste." 

**Public Lab**, under the heading Water Quality Parameters https://publiclab.org/wiki/water-quality-parameters, also describes the significance of measuring water quality for variables such as electrical conductivity, pH, temperature and oxidation-reduction potential (ORP). 

A detailed report published in Catchment News on August 13, 2017, entitled[ ["**Catchments, water quality and community science** – a tale from County Antrim](null)" ](null) provides an informative insight into a coalition between an academic institution, Queens University Belfast, and a community organization,  Sixmilewater River Trust, who were concerned as a result of "Extensive pasture and associated drainage of wet soils, coupled with widespread intensive livestock rearing units, form a significant suite of potentially polluting agricultural activities, while other pressures on water quality can include (on-site and centralised) sewage disposal, urbanisation, landfills and manufacturing industry." The collaboration demonstrated that **"Community science initiatives can have a range of benefits, including generating community support for conservation, providing local knowledge to researchers and offering additional human resources to assist in data acquisition."**

The **Sixmilewater River Trust** community scientists conducted "seven rounds of Temperature/specific electrical conductivity measurements, made at 38 monitoring points across the 278km2 catchment during the eight week period, revealed specific electrical conductivity to vary from just under 55mS/cm to just over 200mS/cm."  The volunteers utilized data loggers in 2015 and their results "revealed  a gradual increase in specific electrical conductivity, corresponding to a decline in river discharge; this was interspersed with sharp declines (and recoveries) in specific electrical conductivity following periods of intense rainfall." Moreover, "**Comparison of the results of specific electrical conductivity measurements with those of laboratory analyses revealed an excellent correlation with chloride concentrations."
**
Review of the full article https://www.catchments.ie/catchments-water-quality-community-science-tale-co-antrim/ may provide some guidance to community science initiatives seeking to replicate the project in their own communities, plagued by analygous water quality vulnerabilities.