Determinants of plasma PCB, brominated flame retardants, and organochlorine pesticides in pregnant women and 3 year old children in The Norwegian Mother and Child Cohort Study.

BACKGROUND: Exposure to persistent organic pollutants (POPs) during prenatal and postnatal life has been extensively studied in relation to adverse health effects in children. OBJECTIVES: The aim was to identify determinants of the concentrations of polychlorinated biphenyls (PCBs), brominated flame retardants (polybrominated diphenyl ethers, PBDEs; polybrominated biphenyl, PBB), and organochlorine pesticides (OCPs) in blood samples from pregnant women and children in The Norwegian Mother and Child Cohort Study (MoBa). METHODS: Blood samples were collected from two independent subsamples within MoBa; a group of women (n=96) enrolled in mid-pregnancy during the years 2002-2008 and a group of 3 year old children (n=99) participating during 2010-2011. PCB congeners (74, 99, 138, 153, 180, 170, 194, 209, 105, 114, 118, 156, 157, 167, and 189), brominated flame retardants (PBDE-28, 47, 99, 100, 153, 154, and PBB-153), as well as the OCPs hexachlorobenzene (HCB), oxychlordane, 4,4'dichlorodiphenyltrichloroethane (DDT), and 4,4'dichlorodiphenyldichloroethylene (DDE) were measured in both pregnant women and children. RESULTS: Age, low parity, and low pre-pregnant BMI were the most important determinants of increased plasma concentrations of POPs in pregnant women. In 3 year old children, prolonged breastfeeding duration was a major determinant of increased POP concentrations. Estimated dietary exposure to PCBs during pregnancy was positively associated with plasma concentrations in 3 year old children, but not in pregnant women. Plasma concentrations were approximately 40% higher in children compared to pregnant women. CONCLUSIONS: Several factors associated with exposure and toxicokinetics, i.e. accumulation, excretion and transfer via breastmilk of POPs were the main predictors of POP levels in pregnant women and children. Diet, which is the main exposure source for these compounds in the general population, was found to predict PCB levels only among children. For the PBDEs, for which non-dietary sources are more important, toxicokinetic factors appeared to have less predictive impact.

PCB in serum and hand wipes from exposed residents living in contaminated high-rise apartment buildings and a reference group.

Exposure to polychlorinated biphenyls (PCB) in buildings constructed with PCB-containing materials can lead to increased body burden of PCB for building users. Exposure to PCB from building related sources was assessed by measuring PCB in serum and hand wipes in two groups of tenants living in the same building estate in apartments constructed with and without PCB. The median serum levels of the sum of 19 PCB congeners was 777 ng/g lw (5-95th percentile: 219-2576 ng/g lw) for the exposed group and 282 ng/g lw (5-95th percentile: 49.8-797 ng/g lw) for the reference group. The congener pattern in serum of the exposed was shifted towards lower chlorinated congeners and was dominated by tri- and tetrachlorinated congeners. The largest difference in serum levels between the groups was observed for PCB-28, with median levels of the exposed being 70 times higher than in the reference group. For very persistent lower chlorinated congeners, like PCB-28, 66 and 74, an increase with residence times was observed as a result of accumulation over time. Less persistent congeners such as PCB-44 and 70 were also elevated in the exposed group -but independent of residence time. The less persistent congeners can therefore be used as markers of recent exposure to original PCB sources. The hand wipes also showed a large exposure contrast, e.g. PCB-28 being more than 60 times higher in the exposed group compared to the reference group (medians 14.4 and 0.23 ng/wipe, respectively) and no overlap between the groups. All measured di- to pentaPCB congeners were significantly higher in hand wipes from the exposed group compared with the reference group. Thus hand wipes seem to be a good, non-invasive screening tool for ongoing indoor exposure to PCB. Furthermore, the measured level of PCB on hand wipes was significantly correlated to PCB in blood for almost all congeners. In conclusion, PCB exposure in contaminated buildings can contribute significantly to the exposure and total body burden of PCB and the lower chlorinated congeners can make up the majority of the total PCB body burden.