Intake of Iodine and Perchlorate and Excretion in Human Milk

Abstract

Perchlorate, thiocyanate, and iodine excretion in urine and milk of 13 breastfeeding women was investigated and the results were interpreted by a model of parallel/competitive transport of these species by the sodium iodide symporter. For each species i, we assumed physiological homeostasis, where i T,in equals the corresponding total excretion in urine and milk (i e,u + i e,m ). The fraction of the total excretion that appeared in milk f i,m was measured and ranged from 0.394-0.781, 0.018-0.144, and 0.086-0.464 for perchlorate, thiocyanate, and iodine, respectively. The corresponding median values were 0.541, 0.053, and 0.177, respectively. The selectivity factors of perchlorate over iodide transport, and thiocyanate over iodide transport, defined as f PC,m /f I,m , and f SCN,m /f I,m , respectively, were 3.14 ( 1.20 and 0.27 ( 0.26 while PC T,in , SCN T,in , and I T,in among individuals varied 4.9, 5.0, and 8.4×, respectively. These transport selectivities are an order of magnitude lower than those indicated by in vitro studies, suggesting that the impact of both these anions on inhibiting iodide transport in milk may have been overestimated in the extant literature. On the other hand, our results showed that 12 of 13 infants did not have an adequate intake of iodine as defined by the Institute of Medicine and 9 out of 13 infants were likely ingesting perchlorate at a level exceeding the reference dose suggested by the National Academy of Science panel.

Environmental Perchlorate and Thiocyanate Exposures and Infant Serum Thyroid Function

“…Recent studies, among which 57 women were the largest sample, report a range of median breast milk iodine levels from 35-155 lg/L (8,32,(40)(41)(42). We reported that the median breast milk iodine concentration in 57 Boston-area women was 155 lg/L (8), similar to that of a 1984 study of 37 women (178 lg/L), but higher than those (33.5, 37.9, 43.0, 55.2, and 71.3 lg/L) reported recently in four studies (32,40,41,43) and in the present report. Kirk et al reported that breast milk iodide and perchlorate levels were inversely correlated in six samples with perchlorate concentrations of ‡ 10 lg/L, although there were no correlations between breast milk iodide and perchlorate in the full data set (32).…”

On the stability of perchlorate ions against reductive attacks in electrochemical systems and in the environment

“…One of the main health hazards is connected with the very fact that perchlorate interferes with iodide uptake in the thyroid gland [35,36]. In large doses, it has been linked to anemia and fetal brain damage [30,35].…”

Placental transfer of and infantile exposure to perchlorate

“…Similarly, the concentrations of perchlorate found in breast milk in Nanchang, China were 3e8 times greater than the values reported from the U.S. (Fig. 1, mean: 5.80e10.6 ng mL À1 , median: 2.50e7.30 ng mL À1 ) (Borjan et al, 2011;Dasgupta et al, 2008;Kirk et al, 2007Kirk et al, , 2012Kirk et al, , 2005Leung et al, 2012;Leung et al, 2009). It is a tradition in China to display fireworks and firecrackers during celebration; in Nanchang city, approximately 376 tons of fireworks trashes were generated in 2012 during the 7-day Chinese New Year celebration.…”

“…1. To our knowledge, nearly all previously studies on perchlorate in the breast milk, infant formula and urine of infants were from the U.S. (Borjan et al, 2011;Dasgupta et al, 2008;Kirk et al, 2007Kirk et al, , 2012Kirk et al, , 2005Leung et al, 2012;Leung et al, 2009;Pearce et al, 2007;Valentin-Blasini et al, 2011), but several studies reported perchlorate concentrations in infant formula from Canada (Wang et al, 2011), Korea (Her et al, 2010;Lee et al, 2012) and Japan (Asami et al, 2013). The urinary concentrations of perchlorate that were detected among all infants from Nanchang, China were up to 20 (range: 2e20) fold higher than those of American infants (Fig.…”

“…It can originate from the use of perchlorate salts in military, industrial and commercial products as an oxidizing agent in solid rocket fuel, munitions, air bag inflators, road flares, explosives and fireworks (DasGupta et al, 2006;Parker, 2009;Susarla et al, 1999). Some studies have suggested that perchlorate also can be formed naturally through atmospheric processes Kounaves et al, 2010).…”