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A platform for research: civil engineering, architecture and urbanism
Tetrabromobisphenol-A, hexabromocyclododecane and its degradation products in UK human milk: Relationship to external exposure
Abstract Tetrabromobisphenol-A (TBBP-A), hexabromocyclododecane (HBCD) and its degradation products were determined in 34 human milk samples from Birmingham, UK. TBBP-A was detected in 36% of samples (average=0.06ngg−1 lw), with HBCDs detected in all samples (average ΣHBCDs=5.95ngg−1 lw). α-HBCD comprised 62–95% ΣHBCDs while β- and γ-HBCD constituted 2–18% and 3–33% respectively. Enantioselective enrichment of (−)-α-HBCD (average enantiomer fraction=0.29) was observed indicating potential enantioselectivity associated with HBCD absorption, metabolism and/or excretion. The degradation products pentabromocyclododecenes (average=0.04ngg−1 lw; n =9) and tetrabromocyclododecadienes (average=0.15ngg−1 lw; n =25) were detected for the first time in human tissues. Average exposures of a nursing infant to ΣHBCDs and TBBP-A (35 and 1ngkg−1 bwday−1 respectively) via breast milk exceeded upper-bound dietary intakes of both UK adults and toddlers. Using a simple pharmacokinetic model, intakes of UK adults via inhalation, diet and dust ingestion were converted to predicted body burdens. Predictions compared well with those observed for HBCDs but observed body burdens of TBBP-A exceeded predictions. This may indicate the human half-life of TBBP-A is greater than observed previously, that intakes may be underestimated, or that concentrations reported here reflect recent elevated episodic exposure.
Research Highlights ► Lower brominated HBCD derivatives (PBCDs and TBCDs) were detected in human milk. ► α-HBCD was predominant in all studied human milk samples. ► Enrichment of (-)-α-HBCD indicates in vivo enantioselective processes. ► Infants exposure to target BFRs via milk exceeded adult and toddler dietary intakes. ► Adult intakes of HBCD and TBBPA were compared to body burdens using a PK model.
Tetrabromobisphenol-A, hexabromocyclododecane and its degradation products in UK human milk: Relationship to external exposure
Abstract Tetrabromobisphenol-A (TBBP-A), hexabromocyclododecane (HBCD) and its degradation products were determined in 34 human milk samples from Birmingham, UK. TBBP-A was detected in 36% of samples (average=0.06ngg−1 lw), with HBCDs detected in all samples (average ΣHBCDs=5.95ngg−1 lw). α-HBCD comprised 62–95% ΣHBCDs while β- and γ-HBCD constituted 2–18% and 3–33% respectively. Enantioselective enrichment of (−)-α-HBCD (average enantiomer fraction=0.29) was observed indicating potential enantioselectivity associated with HBCD absorption, metabolism and/or excretion. The degradation products pentabromocyclododecenes (average=0.04ngg−1 lw; n =9) and tetrabromocyclododecadienes (average=0.15ngg−1 lw; n =25) were detected for the first time in human tissues. Average exposures of a nursing infant to ΣHBCDs and TBBP-A (35 and 1ngkg−1 bwday−1 respectively) via breast milk exceeded upper-bound dietary intakes of both UK adults and toddlers. Using a simple pharmacokinetic model, intakes of UK adults via inhalation, diet and dust ingestion were converted to predicted body burdens. Predictions compared well with those observed for HBCDs but observed body burdens of TBBP-A exceeded predictions. This may indicate the human half-life of TBBP-A is greater than observed previously, that intakes may be underestimated, or that concentrations reported here reflect recent elevated episodic exposure.
Research Highlights ► Lower brominated HBCD derivatives (PBCDs and TBCDs) were detected in human milk. ► α-HBCD was predominant in all studied human milk samples. ► Enrichment of (-)-α-HBCD indicates in vivo enantioselective processes. ► Infants exposure to target BFRs via milk exceeded adult and toddler dietary intakes. ► Adult intakes of HBCD and TBBPA were compared to body burdens using a PK model.
Tetrabromobisphenol-A, hexabromocyclododecane and its degradation products in UK human milk: Relationship to external exposure
Abdallah, Mohamed Abou-Elwafa (author) / Harrad, Stuart (author)
Environmental International ; 37 ; 443-448
2010-11-17
6 pages
Article (Journal)
Electronic Resource
English