title: Derivation of exposure factors for infant lactational exposure to persistent organic pollutants (POPs).
abstract: Quantifying the influence of breastfeeding on infant's dose and biological levels is critical for the risk assessment of persistent organic pollutant (POP) early exposures. We aimed to quantify infants' exposure relative to the mother for POPs. Using a validated pharmacokinetic model, Monte-Carlo simulations of infants' exposure during the first 2 years of life for POPs of different half-lives (i.e., 1-20 years) were performed. Infant:mother (I:M) ratios for dose and biological levels throughout infancy were derived. To evaluate model accuracy, simulated I:M biological level ratios were compared to ratios calculated from Inuit mothers' and infants' measured plasma levels of 2,2',4,4',5,5'-hexachlorobiphenyl (PCB-153), p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) and hexachlorobenzene (HCB). Practically all measured I:M biological level ratios from the Inuit cohort fell below the 95th percentile of the distributions of simulated PCB-153, p,p'-DDE and HCB levels. Peak I:M dose ratios were observed at the beginning of lactation with 95th percentile values of 13, 53, 84, 102 and 113 for half-lives of 1, 5, 10, 15 and 20 years, respectively. In contrast, peak I:M biological level ratios occurred after approximately 1 year of breastfeeding and plateaued at approximately 10.5 (95th percentile) for chemicals of half-lives >5 years. Simulated I:M dose and biological level ratios could be employed in risk assessment of early POP exposures through breastfeeding.
authors.affiliation: Department of Environmental and Occupational Health, School of Public Health, Université de Montréal, Montréal, QC, Canada; Université de Montréal Public Health Research Institute (IRSPUM), Université de Montréal, Montréal, QC, Canada; Chair in Toxicological Risk Assessment and Management, Université de Montréal, Montreal, QC, Canada. Electronic address: sami.haddad@umontreal.ca.
authors.forename: Sami
authors.initials: S
authors.lastname: Haddad
authors.affiliation: Axe santé des populations et pratiques optimales en santé, Centre de recherche du CHU de Québec, Québec, QC, Canada; Département de médecine sociale et préventive, Université Laval, Québec, QC, Canada.
authors.forename: Pierre
authors.initials: P
authors.lastname: Ayotte
authors.affiliation: Department of Environmental and Occupational Health, School of Public Health, Université de Montréal, Montréal, QC, Canada; Université de Montréal Public Health Research Institute (IRSPUM), Université de Montréal, Montréal, QC, Canada; Chair in Toxicological Risk Assessment and Management, Université de Montréal, Montreal, QC, Canada; Department of Environmental Health, Harvard School of Public Health, Boston, MA, USA.
authors.forename: Marc-Andre
authors.initials: MA
authors.lastname: Verner
mesh_terms: D000328:Adult; D001942:Breast Feeding / Q000009:adverse effects* / Q000639:trends; D004781:Environmental Exposure / Q000009:adverse effects*; D004785:Environmental Pollutants / Q000633:toxicity*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007774:Lactation / Q000187:drug effects / Q000378:metabolism; D008297:Male; D018811:Maternal Exposure / Q000009:adverse effects*; D008954:Models, Biological; D009010:Monte Carlo Method
chemical_list: D004785:Environmental Pollutants
keywords: Breast milk; Exposure; Exposure factor; Infant; Infant:mother ratio; PBPK modeling; Persistent organic pollutants; Pharmacokinetic; Risk assessment; Variability