Persistent organic pollutants in human milk of Belgian mothers: levels, time trend and exposure assessment for nursing infants

Human milk samples (n = 206) collected in 2014 from Belgian primiparous mothers were analyzed for seven groups of persistent organic pollutants (POPs): dichlorodiphenyltrichloroethane and its metabolites (DDTs), chlordane compounds (CHLs), hexachlorocyclohexane isomers (HCHs), hexachlorobenzene (HCB), polybrominated diphenyl ethers (PBDEs), pentachlorobenzene (PeCB), and hexabromobiphenyl (BB-153). Pooled samples for the analysis of hexachlorobutadiene, heptachlor, chlordecone, dieldrin, and hexabromocyclododecane (HBCD) were prepared. DDTs [median: 41 ng/g lipid weight (lw)], HCB (5.5 ng/g lw), and HCHs (2.4 ng/g lw) were the predominant compounds in all samples. Median levels of PBDEs (0.91 ng/g lw) in Belgian human breast milk samples were lower compared to other European countries. The major PBDE congeners were BDE-47 and BDE-153, and total PBDE levels were low (0.30-4.25 ng/g lw). α-HBCD was the only HBCD stereoisomer found in the pooled milk samples (2.5 ng/g lw). All targeted POPs were determined in a national pooled sample but were lower than levels of most POPs [organochlorine pesticides (OCPs), PBDEs, and polychlorinated biphenyls (PCBs)] observed in 2006. The daily dietary intake of POPs via human milk was estimated for nursing infants of 1 month [intake of 260 mL milk/kg body weight (bw)] and compared with either health-based guidance values (HBGV) or the reference point (margin of exposure, MOE). The exposure assessment in a worst-case scenario revealed no concern for most POPs. However, the infants were exposed to levels of 60 pg total WHO2005-TEQ/kg bw/week, indicating a possible risk during their life. Based on the MOE approach, 95th percentile of concentration can result in a health concern for congeners BDE-99 and BDE-153.