where does the salt come from in the great salt lake
Great Salt Lake Most of the salts dissolved in the lake and deposited in the desert flats around it reflect the concentration of solutes by evaporation; Lake Bonneville itself was fresh enough to support populations of fish.[31][32] More salt is added yearly via rivers and streams, though the amount is much less than the relict salt from Bonneville.[31]
Iodised salt In the U.S. in the early 20th century, goitre was especially prevalent in the region around the Great Lakes and the Pacific Northwest.[24] David Murray Cowie, a professor of paediatrics at the University of Michigan, led the U.S. to adopt the Swiss practice of adding sodium iodide or potassium iodide to table and cooking salt. On May 1, 1924, iodised salt was sold commercially in Michigan.[25] By the fall of 1924, Morton Salt Company began distributing iodised salt nationally. There was a gradual increase in average intelligence of 1 standard deviation, 15 points, in iodine-deficient areas and 3.5 points nationally.[26]