This is one reason why people know that mercury and aluminum is chelated out using iodine.
"The bioavailability of a Lugol tablet (Iodoral ) containing 12.5 mg elemental iodine was evaluated by measuring 24 hr urine levels of iodide together with the minerals, trace elements and toxic metals before and after administration of this preparation. The results obtained following iodine supplementation revealed that in some subjects, the urine levels of mercury, lead and cadmium increased by several fold after just one day of supplementation. For aluminum, this increased excretion was not observed usually until after one month or more on the iodine supplementation."