GC: n
CT: Specific conductance is a measure of the electric current in the water sampled carried by the ionized substances, therefore the dissolved solids are basically related to this measure that is also influenced by the good conductivity of inorganic acids, bases and salts the poor conductivity characteristics of organic compounds.
S: http://chemistry.tutorvista.com/physical-chemistry/specific-conductance.html (last access: 22 February 2015)
N: 1. Specific Conductance (SC) is a measure of how well water can conduct an electrical current. Conductivity increases with 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. Therefore, SC is an indirect measure of the presence of dissolved solids such as chloride, nitrate, sulfate, phosphate, sodium, magnesium, calcium, and iron, and can be used as an indicator of water pollution.
2. Measurement of SC
Specific Conductance measures how well water can conduct an electrical current for a unit length and unit cross-section at a certain temperature. More specifically, it is defined as the “reciprocal (opposite) of the resistance in ohms measured between opposite faces of a centimeter cube of an aqueous solution at a specified temperature” (Hem, 1985). That is,
conductance = 1 / resistance
Specific conductance is measured using a sensor which measures resistance. Resistance means how well something can resist an electrical current, and is reported in ohms. The unit of conductance was originally ohm spelled backwards – “mho.” More recently, however, the name “siemen” has been used to match the term used by the International System of Units. So both “mho” and “siemen” are sometimes seen in water quality reports. One siemen is equal to one mho. Because SC in natural waters is usually much less than 1 siemen/cm, SC is usually reported in microsiemens (1/1,000,000 siemen) per centimeter, or µS/cm. SC is affected by temperature, so for consistency SC values are converted to what they would be at room temperature (25° C).
S: 1 & 2. http://bcn.boulder.co.us/basin/data/COBWQ/info/SC.html (last access: 22 February 2015).
SYN: electrical conductivity
S: TERMIUMPLUS
