Brominated and fluorinated organic pollutants in the breast milk of first-time Irish mothers: is there a relationship to levels in food?

Abstract

Brominated flame retardants – polybrominated diphenyl ethers (PBDEs), polybrominated biphenyls (PBBs), hexabromocyclododecane (HBCD) and others – have been measured in 11 pooled breast milk samples from 109 first-time mothers in Ireland. Additionally, the study has measured levels of polybrominated dibenzo-p-dioxins and furans (PBDD/Fs), mixed halogenated dioxins (PXCC/Fs) and biphenyls (PXBs), polychlorinated naphthalenes (PCNs) and perfluoroalkylated substances (PFAS) in these samples. The mean sum of 19 PBDEs including BDE-209 was 4.85 ng g⁻¹ fat, which is comparable with that found in other European countries. BDE-47, BDE-153, BDE-209, BDE-99 and BDE-100 were found at the highest concentrations. The only PBBs detected consistently were BB-77, BB-126 and BB-153, with highest concentrations being found for BB-153 (mean = 0.13 ng g⁻¹ fat). The mean sum of HBCD enantiomers was 3.52 ng g⁻¹ fat, with α-HBCD representing over 70% of the total. Of the other brominated flame retardants – tetrabromobisphenol-A (TBBP-A), hexabromobenzene (HBB), decabromodiphenylethane (DBDPE) and bis(2,4,6-tribromophenoxyethane) (BTBPE) – examined, only TBBP-A was detected above the limit of detection (LOD), in two of the 11 pools analysed. All measured PBDF congeners were observed (at 0.02–0.91 pg g⁻¹ fat), but 2,3,7,8-tetrabromo-dibenzodioxin (TeBDD) was the only PBDD detected, with a mean concentration of 0.09 pg g⁻¹ fat. The occurrence of the mixed chlorinated/brominated dibenzodioxins, dibenzofurans and biphenyls, 2-B-3,7,8-CDD, 2,3-B-7,8-CDF, 4-B-2,3,7,8-CDF, PXB 105, PXB 118, PXB 126 and PCB 156 in breast milk in the current study may indicate that levels of these contaminants are increasing in the environment. Polychlorinated naphthalenes were detected in all samples, but not perfluorooctane sulfonate (PFOS) and other PFAS. The pattern of occurrence of these brominated and fluorinated persistent organic pollutants (POPs) in Irish breast milk shows a general relationship to their occurrence in food, as reported in a number of surveillance studies carried out by the Food Safety Authority of Ireland.

Keywords:

• breast milk
• persistent organic pollutants
• brominated flame retardants
• mixed halogenated dioxins and biphenyls
• PBDEs
• HBCD
• PBBs
• PBDD/Fs
• PCN
• PFAS
• emerging BFRs

Acknowledgements

Our special gratitude to the mothers who donated milk samples for this study; and to Therese Hughes, lactation consultant at University College Hospital Galway; Julie Sloane and Suganthi Jerome, research midwives at the Coombe Hospital, Dublin; Aisling Bhreathnach and Maura Lavery, lactation consultants at the Rotunda Hospital, Dublin; Catherine McCann, Denise McGuinness and Lorraine O’Hagan, lactation consultants at Holles Street Hospital, Dublin; and Aine Brady, Food Safety Authority of Ireland for their kind help in collection of samples and collaboration. Without their support this study would not have been possible.