Exposure assessment of Dutch nursing infants to brominated flame retardants via breast milk

As part of a national survey on the occurrence of persistent organic contaminants in breast milk, a group of brominated flame retardants (polybrominated diphenyl ethers or PBDEs) was measured in breast milk which had been collected in 1998 from Dutch primiparous women on day 6 to 10 after labour. Together with data on milk intake, body weight and the duration of breast feeding these data were taken as a starting point for the calculation of the exposure to PBDEs via breast milk. The cumulative exposure was calculated for 10 PBDE congeners and for breast feeding periods of 8 days and 1, 2, 3, 4, 5, 6, 7.5 and 9 months. The mean, standard deviation, minimum, maximum, 5th and 95th percentile of these exposure doses were calculated. The mean cumulative exposure of the sum of the PBDEs was 2.9 mu g/kg bw (95th percentile 6.6 mu g/kg bw) for a breast feeding period of 6 months and 3.8 mu g/kg bw (95th percentile 8.6 mu g/kg bw) for a period of 9 months. BDE #47 contributed about 35 % to the total intake, while BDEs #153, #99, #183 en #100 contribute each. It appears that at 6 months the daily exposure of nursing infants to PBDEs via breast milk is about 6 times higher than the exposure of adults via food (the latter was calculated in an earlier study). In addition to the exposure to PBDEs, nursing infants are also expected to be exposed to the brominated flame retardant hexabromocyclododecane (HBCD). Consequently, measurements of HBCD in breast milk, followed by a risk assessment for nursing infants, is recommended