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First Reader

Dr. Joe Nix


Calcium compounds are abundant in nature. The carbonate ion may exist in many varieties, such as aragonite and limestone. Of major importance in the following discussion, however, is calcite. Calcium carbonate may well be of animal origin, prime examples being sea shells, coral, and chalk. Dolomite, on the other hand, is a double carbonate of calcium and magnesium. Calcium in natural waters exists mainly as a bicarbonate, Ca(HCO3)2, which is temporary hardness, or as a sulfate, which is permanent hardness.

From determinations made periodically (every two weeks) since August 1966, a decrease has been found in the calcium content as the water progresses downstream. There are two possible explanations for this: 1. Dilution by tributaries, or 2. Saturation and precipitation of calcium carbonate from the water.



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