Perchlorate competitively interferes with iodide uptake by the thyroid gland, making human exposure to perchlorate a public health concern. In this study, we analyzed perchlorate in commercial dairy milk, raw milk, and other dairy samples collected in Japan. Concentrations of perchlorate in Japanese commercial dairy milk samples ranged from 1.03 to 14.1 ng/mL with 100% detection frequency. Analysis of colostrum and raw milk collected from cows fed the same feed for more than 30 days showed no significant temporal variations in perchlorate concentration. Concentrations of perchlorate in feed and drinking water for cattle were 93 ± 46 ng/g (dry wt) and 0.1 ± 0.04 ng/mL, respectively, suggesting that animal feed was the main source of perchlorate contamination in dairy milk. Compared to subjects in other age groups, infants demonstrated the highest estimated perchlorate intake from milk on a body weight basis. However, the estimated intake of perchlorate by infants was far below the daily reference dose.
(Pathology and Pathophysiology Research Division)
References:
Guruge K. et al (2011) J. Environ. Monit. 13(8):2312-2320
