Derivation of exposure factors for infant lactational exposure to persistent organic pollutants (POPs)

Area of Science:

• Environmental Health
• Toxicology
• Pharmacokinetics

Background:

• Infant exposure to persistent organic pollutants (POPs) via breastfeeding is a key concern for early life risk assessment.
• Quantifying infant dose and biological levels relative to maternal levels is critical for understanding POP exposure dynamics.

Purpose of the Study:

• To quantify infant exposure to POPs relative to their mothers during the first two years of life.
• To derive infant:mother (I:M) ratios for both dose and biological levels of POPs.

Main Methods:

• Utilized a validated pharmacokinetic model and Monte-Carlo simulations to model infant POP exposure.
• Simulated POPs with varying half-lives (1-20 years) over the first two years of an infant's life.
• Compared simulated I:M biological level ratios with measured ratios from Inuit mother-infant pairs for specific POPs (PCB-153, p,p'-DDE, HCB).

Main Results:

• Peak I:M dose ratios were highest at lactation's onset, increasing with POP half-life.
• Peak I:M biological level ratios occurred around one year postpartum, plateauing for POPs with half-lives >5 years.
• Measured I:M biological level ratios in the Inuit cohort were generally below the simulated 95th percentile, validating the model.

Conclusions:

• Simulated I:M dose and biological level ratios provide valuable tools for assessing risks associated with early life POP exposure through breastfeeding.
• The model accurately reflects real-world infant exposure levels compared to maternal levels.
• Findings highlight the importance of considering POP half-life in risk assessment for breastfed infants.