Regional differences in levels of chlorinated and brominated pollutants in mother's milk from primiparous women in Sweden

Early life exposure to halogenated persistent organic pollutants, such as polychlorinated biphenyls (PCBs), the DDT metabolite p,p′-dichlorodiphenyldichloroethane (p,p′-DDE), polybrominated diphenylethers (PBDEs), and hexabromocyclododecane (HBCD), may affect human health. We determined if there are regional differences in mother's milk levels of these compounds in Sweden. In year 2000–2004, milk was sampled from 204 randomly recruited primiparas from four regions of Sweden. Levels of the compounds were measured by gas chromatography with dual electron-capture detectors. Women were recruited at delivery in three hospitals located in urban areas in southern and central Sweden (Lund, Gothenburg and Uppsala), and in one hospital located in a more rural area in northern Sweden (Lycksele). Information about dietary habits and medical/life-style factors were collected by questionnaires. Among PCB congeners, CB 153, CB 138 and CB 180 showed the highest median concentrations (18–48 ng/g mother's milk lipid), whereas more than 50% of the women had CB 52, CB 101, CB 114, and CB 157 levels below the LOQ (0.3–1.5 ng/g lipid). Median p,p′-DDE levels were in the range of 46–78 ng/g lipid. BDE 47 showed the highest median concentrations (1–2 ng/g lipid) among the brominated compounds, whereas more than 50% of the women had levels of BDE 28, BDE 66, BDE 138, BDE 154, and HBCD below the LOQ (0.05–0.10 ng/g lipid). Regional differences in median organohalogen compound concentrations were small, less than 2-fold. Lycksele women generally had the lowest levels of Σmono-and Σdi-ortho PCBs, mainly due to a lower average age. In contrast, these women had higher tetra- to penta-brominated PBDE levels, but no diet or life-style factor could explain this finding. Wide ranges of PBDEs and HBCD levels (up to 200-fold) were found, especially in the Lycksele area. The highest levels of PBDE were in the range of average levels found in mother's milk from North America, suggesting that food may not be the only source of exposure to PBDEs among some individuals.