title: Gestational exposure to high perchlorate concentrations in drinking water and neonatal thyroxine levels.
abstract: OBJECTIVE
  To assess the effect of gestational perchlorate exposure through drinking water on neonatal thyroxine (T(4)).
  
  
  METHODS
  T(4) values were compared among newborns in Ramat Hasharon, Israel, whose mothers resided in suburbs where drinking water contained perchlorate < or = 340 microg/L (very high exposure, n = 97), 42-94 microg/L (high exposure, n = 216), and < 3 microg/L (low exposure, n = 843). In the very high and high exposure areas, T(4) values in newborns whose mothers drank tap water exclusively (as determined by a telephone interview) were analyzed as a subset. Serum perchlorate levels in blood from donors residing in the area were used as proxy indicators of exposure.
  
  
  RESULTS
  Neonatal T(4) values (mean +/- SD) in the very high, high, and low exposure groups were 13.9 +/- 3.8, 13.9 +/- 3.4, and 14.0 +/- 3.5 microg/dL, respectively (p = NS). Serum perchlorate concentrations in blood from donors residing in areas corresponding to these groups were 5.99 +/- 3.89, 1.19 +/- 1.37, and 0.44 +/- 0.55 microg/L, respectively. T(4) levels of neonates with putative gestational exposure to perchlorate in drinking water were not statistically different from controls.
  
  
  CONCLUSIONS
  This study finds no change in neonatal T(4) levels despite maternal consumption of drinking water that contains perchlorate at levels in excess of the Environmental Protection Agency (EPA) drinking water equivalent level (24.5 microg/L) based on the National Research Council reference dose (RfD) [0.7 microg/(kg.day)]. Therefore the perchlorate RfD is likely to be protective of thyroid function in neonates of mothers with adequate iodide intake.
authors.affiliation: Department of Mother, Child, and Adolescent Health, Jerusalem, Israel. yona.amitai@moh.health.gov.il
authors.forename: Yona
authors.initials: Y
authors.lastname: Amitai
authors.forename: Gary
authors.initials: G
authors.lastname: Winston
authors.forename: Joseph
authors.initials: J
authors.lastname: Sack
authors.forename: Janice
authors.initials: J
authors.lastname: Wasser
authors.forename: Matthew
authors.initials: M
authors.lastname: Lewis
authors.forename: Benjamin C
authors.initials: BC
authors.lastname: Blount
authors.forename: Liza
authors.initials: L
authors.lastname: Valentin-Blasini
authors.forename: Nirah
authors.initials: N
authors.lastname: Fisher
authors.forename: Avi
authors.initials: A
authors.lastname: Israeli
authors.forename: Alex
authors.initials: A
authors.lastname: Leventhal
mesh_terms: D000328:Adult; D001782:Blood Donors; D004781:Environmental Exposure / Q000032:analysis*; D005260:Female; D005312:Fetal Blood; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007557:Israel; D008297:Male; D010472:Perchlorates / Q000009:adverse effects*; D011247:Pregnancy; D013974:Thyroxine / Q000097:blood*; D014877:Water Pollution, Chemical / Q000032:analysis*
chemical_list: D010472:Perchlorates; D013974:Thyroxine; C494474:perchlorate