Saline water

Saline water is a general term for water that contains a significant concentration of dissolved salts (NaCl). The concentration is usually expressed in parts per million (ppm) of salt.

The salinity concentration level used by United States Geological Survey classifies saline water in three categories. Slightly saline water contains around 1,000 to 3,000 ppm. Moderately saline water contains roughly 3,000 to 10,000 ppm. Highly saline water has around 10,000 to 35,000 ppm of salt. Seawater has a salinity of roughly 35,000 ppm, equivalent to 35 g/L.

Because of scarcity of fresh water in some areas of the world, saline water is used by desalinating it. For example, in Colorado, water having up to 2,500 ppm of salt is used for irrigating crops. Saline water, known as saline, is also used in medicine as a sterile solution.

Normally, moderately or highly salinated water is of little use to humans. Humans cannot drink salinated water directly, nor is it suitable for irrigating crops.

Some industries also make use of saline water, such as mining and thermoelectric-power.

Saline water use in the United States

In the United States, 14 percent of all water used in 2000 was saline. [http://ga.water.usgs.gov/edu/salineuses.html Uses of saline water] , USGS] Almost all saline withdrawals, over 92 percent, were used by the thermoelectric-power industry to cool electricity-generating equipment. About three percent of the nation's saline water was used for mining and other industrial purposes.

Due to their proximity to the Atlantic and Pacific Oceans, states near the coast make the most use of saline water. Almost 40% of all saline water use in 2000 occurred in California, Florida, and Maryland.

The use of saline water, as with freshwater, has been trending downward since a peak in 1968. But, in the period between 1950 and 1968, the use of saline water increased at a much higher rate than freshwater use.

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