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Adverse Effects and Perchlorate. UNMC SoS Symposium. UNMC SoS Symposium. Subnormal circulating T3. Adverse. Developmental delays. Hypothyroxinema. Subnormal circulating TSH. Pre-adaptive or Adaptive. Iodide uptake inhibition. Increased perchlorate excretion.
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UNMC SoS Symposium Subnormal circulating T3 Adverse Developmental delays Hypothyroxinema Subnormal circulating TSH Pre-adaptive or Adaptive Iodide uptake inhibition Increased perchlorate excretion
Definitional Ambiguity 1 • TERA (‘adverse effect or precursor’) • “first adverse effect, or its known precursor, that occurs as dose rate or exposure level increases” (2002 RfD) • “known and immediate precursor” [citing Barnes and Dourson 1988, p. 473] (2005 EHP letter) • p. 473 is not revealing • ‘precursor’ appears out of context; ‘immediate’ does not appear’ • ‘there may be sound professional differences of opinion in judging whether or not a particular response is adverse’ (p. 480)
Definitional Ambiguity 2 • EPA • ‘Adverse Effect’: ‘A biochemical change, functional impairment, or pathologic lesion that affects the performance of the whole organism or reduces an organism's ability to respond to an additional environmental challenge’ (EPA 2002, p. G-1) • ‘Key Event’: ‘an empirically observable precursor step that is a necessary element of the mode of action or is a marker for such an element’ (2002 ClO4 RA, p. 7-4).