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Incorporation of fetal and child PFOA dosimetry in the derivation of health-based toxicity values
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Jan 08 2018
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Source: Environ Int. 111:260-267
Details:
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Alternative Title:Environ Int
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Personal Author:
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Description:Background:
Multiple agencies have developed health-based toxicity values for exposure to perfluorooctanoic acid (PFOA). Although PFOA exposure occurs in utero and through breastfeeding, current health-based toxicity values have not been derived using fetal or child dosimetry. Therefore, current values may underestimate the potential risks to fetuses and nursing infants.
Objective:
Using fetal and child dosimetry, we aimed to calculate PFOA maternal human equivalent doses (HEDs), corresponding to a developmental mouse study lowest observed adverse effect level (LOAEL, 1 mg/kg/day). Further, we investigated the impact of breastfeeding duration and PFOA half-life on the estimated HEDs.
Methods:
First, a pharmacokinetic model of pregnancy and lactation in mice was used to estimate plasma PFOA levels in pups following a maternal exposure to 1 mg PFOA/kg/day for gestational days 1–17. Four plasma PFOA concentration metrics were estimated in pups: i) average prenatal; ii) average postnatal; iii) average overall (prenatal and postnatal); and iv) maximum. Then, Monte Carlo simulations were performed using a pharmacokinetic model of pregnancy and lactation in humans to generate distributions of maternal HEDs that would result in fetal/child plasma levels equivalent to those estimated in pups using the mouse model. Median (HED50) and 1st percentile (HED01) of calculated HEDs were calculated.
Results:
Estimated PFOA maternal HED50s ranged from 3.0 × 10−4 to 1.1 × 10−3 mg/kg/day and HED01s ranged from 4.7 × 10−5 to 2.1 × 10−4 mg/kg/day. All calculated HEDs were lower than the HED based on adult dosimetry derived by the Environmental Protection Agency (EPA) (5.3 × 10−3 mg/kg/day).
Conclusion:
Our results suggest that fetal/child dosimetry should be considered when deriving health-based toxicity values for potential developmental toxicants.
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Source:
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Pubmed ID:29325971
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Pubmed Central ID:PMC6234970
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