Strontium
Source of Strontium
Strontium (Sr) is in the same family as calcium and magnesium, and is one of the polyvalent earth metals that shows up as hardness in the water. The presence of strontium is usually restricted to areas where there are lead ores, and its concentration in water is usually very low. Strontium sulfate is a critical reverse osmosis membrane foulant, dependent on its concentration. There is no MCL for strontium listed in the US EPA Drinking Water Standards.Treatment of Strontium
Strontium can be removed with strong acid cation exchange resin. It can be in sodium form as in a water softener or the hydrogen form as in the cation portion of a two-column deionizer. Reverse osmosis will also reduce strontium but as stated above strontium sulfate is a membrane foulant.