Freshwater rivers and lakes naturally contain low concentrations of chloride. Freshwater generally has chloride concentrations below 100 mg/L.
What is it?
Chloride is a naturally occurring ion found dissolved in water. Ions are atoms or molecules with a positive or negative charge. Chloride is often measured as an indication of salinity, or the saltiness of water. However, other ions also affect salinity, such as calcium, magnesium, sodium, potassium, carbonate and bicarbonate.
Chloride in water can come from natural sources (such as the weathering of rocks and soils) as well as from human activity (such as road salts, industrial and municipal effluent, and agricultural inputs).