Perchlorate Exposure of the US Population, 2001–2002

Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA 30341, USA.
Journal of Exposure Science and Environmental Epidemiology (Impact Factor: 3.05). 08/2007; 17(4):400-7. DOI: 10.1038/sj.jes.7500535
Source: PubMed

ABSTRACT Perchlorate is commonly found in the environment and can impair thyroid function at pharmacological doses. As a result of the potential for widespread human exposure to this biologically active chemical, we assessed perchlorate exposure in a nationally representative population of 2,820 US residents, ages 6 years and older, during 2001 and 2002 as part of the National Health and Nutrition Examination Survey (NHANES). We found detectable levels of perchlorate (>0.05 microg/l) in all 2,820 urine samples tested, indicating widespread human exposure to perchlorate. Urinary perchlorate levels were distributed in a log normal fashion with a median of 3.6 microg/l (3.38 microg/g creatinine) and a 95th percentile of 14 microg/l (12.7 microg/g creatinine). When geometric means of urinary perchlorate levels were adjusted for age, fasting, sex and race-ethnicity, we found significantly higher levels of urinary perchlorate in children compared with adolescents and adults. We estimated total daily perchlorate dose for each adult (ages 20 years and older), based on urinary perchlorate, urinary creatinine concentration and physiological parameters predictive of creatinine excretion rate. The 95th percentile of the distribution of estimated daily perchlorate doses in the adult population was 0.234 microg/kg-day [CI 0.202-0.268 microg/kg-day] and is below the EPA reference dose (0.7 microg/kg-day), a dose estimated to be without appreciable risk of adverse effects during a lifetime of exposure. These data provide the first population-based assessment of the magnitude and prevalence of perchlorate exposure in the US.

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    ABSTRACT: Perchlorate is a widespread environmental contaminant and potent thyroid hormone disrupting compound. Despite this, very little is known with regard to the occurrence of this compound in indoor dust and the exposure of humans to perchlorate through dust ingestion. In this study, 366 indoor dust samples were collected from 12 countries,, during 2010–2014. Dust samples were extracted by 1% (v/v) methylamine in water. Analyte separation was achieved by an ion exchange (AS-21) column and analysis was performed by high performance liquid chro-matography–tandem mass spectrometry (HPLC–MS/MS). The overall concentrations of perchlorate in dust were in the range of 0.02–104 μg/g (geometric mean: 0.41 μg/g). The indoor dust samples from China contained the highest concentrations (geometric mean: 5.38 μg/g). No remarkable differences in perchlorate concentrations in dust were found among various microenvironments (i.e., car, home, office, and laboratory). The estimated median daily intake (EDI) of perchlorate for toddlers through dust ingestion in the USA,.3 ng/kg body weight (bw)/day, respectively. Although high concen-trations of perchlorate were measured in some dust samples, the contribution of dust to total perchlorate intake was b 5% of the total perchlorate intake in humans. This is the first multinational survey on the occurrence of perchlorate in indoor dust.
    Environment international 02/2015; 80. DOI:10.1016/j.envint.2014.11.005 · 5.66 Impact Factor
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    ABSTRACT: Purpose of review This review will present a general overview of the sources, human studies, and proposed regulatory action regarding environmental perchlorate exposure. Recent findings Some recent studies have reported significant associations between urinary perchlorate concentrations, thyroid dysfunction, and decreased infant intelligence quotient in groups who would be particularly susceptible to perchlorate effects. An update regarding the recently proposed regulatory actions and potential costs surrounding amelioration of perchlorate contamination is provided. Summary The potential adverse thyroidal effects of environmental perchlorate exposure remain controversial, and further research is needed to further define its relationship to human health among pregnant and lactating women and their infants.
    Current Opinion in Endocrinology Diabetes and Obesity 08/2014; 21(5). DOI:10.1097/MED.0000000000000090 · 3.77 Impact Factor
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    ABSTRACT: Perchlorate, an environmental contaminant, disrupts normal functioning of the thyroid. We previously showed that perchlorate disrupts behavior and gonad development, and induces external morphological changes in a vertebrate model organism, the threespine stickleback. Whether perchlorate alters these phenotypes via a thyroid-mediated mechanism, and the extent to which the effects depend on dose, are unknown. To address these questions, we chronically exposed stickleback to control conditions and to three concentrations of perchlorate (10, 30 and 100ppm) at various developmental stages from fertilization to reproductive maturity. Adults chronically exposed to perchlorate had increased numbers of thyroid follicles and decreased numbers of thyrocytes. Surprisingly, T4 and T3 levels in larval, juvenile, and adult whole fish chronically exposed to perchlorate did not differ from controls, except at the lowest perchlorate dose, suggesting a non-monotonic dose response curve. We found no detectable abnormalities in external phenotype at any dose of perchlorate, indicating that the increased number of thyroid follicles compensated for the disruptive effects of these doses. In contrast to external morphology, gonadal development was altered substantially, with the highest dose of perchlorate causing the largest effects. Perchlorate increased the number both of early stage ovarian follicles in females and of advanced spermatogenic stages in males. Perchlorate also disrupted embryonic androgen levels. We conclude that chronic perchlorate exposure may not result in lasting adult gross morphological changes but can produce lasting modifications to gonads when compensation of T3 and T4 levels occurs by thyroid follicle hyperplasia. Perchlorate may therefore affect vertebrate development via both thyroidal and non-thyroidal mechanisms. Copyright © 2014 Elsevier Inc. All rights reserved.
    General and Comparative Endocrinology 01/2015; 210:130-144. DOI:10.1016/j.ygcen.2014.10.015 · 2.67 Impact Factor

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