Abstract
The contamination levels of bisphenol A (BPA) and tetrabromobisphenol A (TeBBPA) were determined in breast milk samples from seventeen Japanese mothers. BPA and TeBBPA were detected in most samples in the ranges of 1.4 –380 ng/g lipid (n ＝17, mean: 35 ng/g lipid) and n.d. – 8.7 ng/g lipid (n ＝17, mean: 2.0 ng/g lipid), respectively. Subsequently, we also observed an extremely interesting unknown peak in the samples, and this peak was identified as tribromobisphenol A (TriBBPA). Then, when we reanalyzed the samples, TriBBPA was also detected in most samples (mean: 6.0 ng/g lipid). The average concentration of TriBBPA was 3.0 times higher than that of TeBBPA. In addition, we investigated time-dependent changes for 24 hr in breast milk of two donors.It was estimated that higher levels of TriBBPA represent a debrominated metabolite of TeBBPA which has been ingested via food. Based on levels of the breast milk, we calculated and compared the daily intake of TeBBPA and TriBBPA for infants through breast milk. The intake of TriBBPA was about 4 times higher than that of TeBBPA.
Further study is needed to clarify the contamination level of not only TeBBPA but also its metabolites in the human, especially infants, and their detailed mechanism of toxicity.
