The salinity of water (also called salinity) is the amount of salt in the water. Since various salts in water generally exist in the form of ions, the salt content can also be expressed as the sum of the amounts of various cations and anions in water.
The salt content of water is different from the meaning of dissolved solids, because dissolved solids include not only dissolved salts in water, but also organic substances. At the same time, the salt content of water and the meaning of total solids are also different, because the total factor includes not only dissolved solids, but also suspended solids that are not soluble in water. Therefore, the dissolved solids and total solids should be higher in quantity than the salt content. However, under less strict conditions, when the water is relatively clean, the content of organic matter in the water is relatively small, and sometimes the content of dissolved solids is used to approximate the salt content in the water. When the water is particularly clean, the content of suspended solids is relatively small (such as groundwater), so sometimes the total solids content can also be used to seem to represent the salt content of the water.