This section is from the book "A Treatise On Beverages or The Complete Practical Bottler", by Charles Herman Sulz. Also available from Amazon: A Treatise On Beverages.
Chatin asserts that all spring-waters contain iodine, and this assertion is supported by the fact that iodine is found in many vegetables and plants that live in sweet water, also in many plants of the earth. The quantity of iodine differs in the various sources of water; mountain water is said to contain the least. Also Marchand proves iodine in all spring waters and in bromine.
All these substances have been found by careful analysis in the real mineral waters, besides the regular saline or mineral constituents. It is understood that they got into the water by the rain flowing through or penetrating the different stratasof the earth, dissolving or absorbing them, and there is in all probability more or less in all our springs or wells - may be but traces.