Iodine supplementation and drinking-water perchlorate mitigation

Abstract

Ensuring adequate iodine intake is important, particularly among women of reproductive age, because iodine is necessary for early life development. Biologically based dose-response modeling of the relationships among iodide status, perchlorate dose, and thyroid hormone production in pregnant women has indicated that iodide intake has a profound effect on the likelihood that exposure to goitrogens will produce hypothyroxinemia. We evaluated the possibility of increasing iodine intake to offset potential risks from perchlorate exposure. We also explored the effect of dietary exposures to nitrate and thiocyanate on iodine uptake and thyroid hormone production. Our modeling indicates that the level of thyroid hormone perturbation associated with perchlorate exposures in the range of current regulatory limits is extremely small and would be overwhelmed by other goitrogen exposures. Our analysis also shows that microgram levels of iodine supplementation would be sufficient to prevent the goitrogenic effects of perchlorate exposure at current regulatory limits among at risk individuals. The human health risks from supplementing drinking water with iodine are negligible; therefore, this approach is worthy of regulatory consideration.

Exogenous iodide ameliorates perchlorate-induced thyroid phenotypes in threespine stickleback

“…For example, Manzon and Youson (1997) found that treatment with exogenous T 4 ameliorated perchlorate-induced decreases in the thyroid hormones of sea lamprey ( Petromyzon marinus ) larvae. Iodine supplementation to drinking water has been evaluated as a solution for preventing goitrogenic effects of perchlorate in humans (Lewandowski et al, 2015). However, an excess of iodide has been shown to induce toxic effects including inflammation, oxidative stress, and even autoimmune disease (Luo et al, 2014).…”

Iodine Addition to Drinking Water for Perchlorate Mitigation: Engineering Feasibility

“…Iodate dose to offset perchlorate health effects. Physiologically based pharmacokinetic modeling relating perchlorate and iodine exposure to potential effects on thyroidal iodine uptake among sensitive populations, examined elsewhere (Lewandowski et al 2015), suggests that up to 1.5 µg I 2 /L (equivalent to 4 µg/L of dissolved iodate) would need to be added to drinking water to offset perchlorate concentrations up to 20 µg/L in drinking water, assuming consumption of approximately 3 L/d of treated water. In this study, a dosing ratio of total iodine (as atomic iodine) to perchlorate (as ClO 4 – ) of 1:2 (by mass) was used as a conservative assumption for iodine target concentrations in treated drinking water based on influent perchlorate concentrations.…”

“…Because perchlorate inhibits thyroidal iodine uptake, additional iodine intake may be able to offset the potential thyroidal health impacts from perchlorate exposure (Lewandowski et al 2015, WHO 2013), and may, in fact, be “the most direct approach to reducing risk of perchlorate exposure to an individual” (Brent 2010). Direct iodine addition to drinking water could therefore represent a novel approach to offsetting the risk of low‐level perchlorate exposure in drinking water.…”

“…Direct iodine addition to drinking water could therefore represent a novel approach to offsetting the risk of low‐level perchlorate exposure in drinking water. Toxicological modeling suggests that increased iodine intake of up to 1.5 µg/L of iodine (as I 2 ) in drinking water (assuming average consumption of 3 L of water/day for an approximate total additional dietary intake of 4.5 µg I 2 /day) could effectively offset the thyroidal iodine uptake inhibition associated with exposure to up to 20 µg/L of perchlorate in drinking water (Lewandowski et al 2015).…”

A Highly Sensitive and Selective Method for the Determination of an Iodate in Table-salt Samples Using Malachite Green-based Spectrophotometry

“…11 Potassium iodate ingested within the human body is captured from the blood into the thyroid gland where it is first deoxidized into iodine to be incorporated in the biosynthesis of different thyroid hormones. 12,13 Adequate intake of iodine can be achieved by the consumption of iodized salt by the addition of potassium iodate to salt samples due to its good stability and bioavailability.…”