Perchlorate exposure and dose estimates in infants
Liza Valentín-Blasini1, Benjamin C Blount, Samaret Otero-Santos
1Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia 30341, USA.
Environmental Science & Technology
|April 1, 2011
Summary
Infant perchlorate exposure is higher than adults, with some infants exceeding safe intake levels. Breast-fed infants show higher perchlorate exposure than formula-fed infants, warranting further health effect research.
Area of Science:
- Environmental Health
- Toxicology
- Pediatrics
Background:
- Perchlorate, an inorganic anion in rocket fuel and explosives, can disrupt thyroid function by inhibiting iodide uptake.
- Infant perchlorate exposure is predicted to be higher than in adults, but data are limited.
- Understanding infant exposure is crucial due to potential thyroid impacts.
Purpose of the Study:
- To measure perchlorate exposure in infants and assess potential health risks.
- To compare perchlorate intake doses across different infant feeding methods.
- To evaluate the influence of iodine status on perchlorate's effects.
Main Methods:
- Collected 206 urine samples from 92 infants (1-377 days old).
- Measured perchlorate, nitrate, thiocyanate, and iodide levels.
- Calculated estimated perchlorate intake doses and compared them to the reference dose (0.7 microg/kg/day).
Main Results:
- Median infant perchlorate exposure was 0.160 microg/kg/day.
- 9% of dose estimates exceeded the reference dose; 6% of infants had multiple high estimates.
- Breast-fed infants had significantly higher perchlorate exposure (0.220 microg/kg/day) than formula-fed infants (0.103 microg/kg/day for cow milk, 0.027 microg/kg/day for soy).
- Infants were iodine-sufficient (median urinary iodide 125 microg/L), potentially mitigating perchlorate's thyroid impact.
Conclusions:
- Infant perchlorate exposure levels vary by feeding method, with breast-fed infants having higher intake.
- A notable percentage of infants exceeded the reference dose, indicating potential concern.
- Further research is necessary to determine the health implications of these perchlorate exposure levels in infants.
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