PFAS levels and exposure determinants in sensitive population groups.

BACKGROUND: Per- and polyfluoroalkyl substances (PFAS) are persistent organic pollutants. The first exposure to PFAS occurs in utero, after birth it continues via breast milk, food intake, environment, and consumer products that contain these chemicals. Our aim was to identify determinants of PFAS concentrations in sensitive population subgroups- pregnant women and newborns. METHODS: Nine European birth cohorts provided exposure data on PFAS in pregnant women (INMA-Gipuzkoa, Sabadell, Valencia, ELFE and MoBa; total N = 5897) or newborns (3xG study, FLEHS 2, FLEHS 3 and PRENATAL; total N = 940). PFOS, PFOA, PFHxS and PFNA concentrations were measured in maternal or cord blood, depending on the cohort (FLEHS 2 measured only PFOS and PFOA). PFAS concentrations were analysed according to maternal characteristics (age, BMI, parity, previous breastfeeding, smoking, and food consumption during pregnancy) and parental educational level. The association between potential determinants and PFAS concentrations was evaluated using multiple linear regression models. RESULTS: We observed significant variations in PFAS concentrations among cohorts. Higher PFAS concentrations were associated with higher maternal age, primipara birth, and educational level, both for maternal blood and cord blood. Higher PFAS concentrations in maternal blood were associated with higher consumption of fish and seafood, meat, offal and eggs. In cord blood, higher PFHxS concentrations were associated with daily meat consumption and higher PFNA with offal consumption. Daily milk and dairy consumption were associated with lower concentrations of PFAS in both, pregnant women and newborns. CONCLUSION: High detection rates of the four most abundant PFAS demonstrate ubiquitous exposure of sensitive populations, which is of concern. This study identified several determinants of PFAS exposure in pregnant women and newborns, including dietary factors, and these findings can be used for proposing measures to reduce PFAS exposure, particularly from dietary sources.

Endocrine actions of pesticides measured in the Flemish environment and health studies (FLEHS I and II).

Within the Flemish Environment and Health studies (FLEHS I, 2002-2006, and FLEHS II, 2007-2012), pesticide exposure, hormone levels and degree of sexual maturation were measured in 14-15-year-old adolescents residing in Flanders (Belgium). In FLEHS II, geometric mean concentrations (with 95 % confidence interval (CI)) of 307 (277-341) and 36.5 ng L(-1) (34.0-39.2) were found for p,p'-dichlorophenyldichloroethylene (p,p'-DDE) and hexachlorobenzene (HCB). These values were respectively 26 and 60 % lower than levels in FLEHS I, 5 years earlier. Metabolites of organophosphorus pesticides (OPPs) and of para-dichlorobenzene were measured for the first time in FLEHS II, yielding concentrations of 11.4, 3.27 and 1.57 µg L(-1) for the sum of dimethyl- and diethyl phosphate metabolites and 2,5-dichlorophenol (2,5-DCP), respectively. Data on internal exposure of HCB showed a positive correlation with sexual maturation, testosterone and the aromatase index for boys and with free thyroxine (fT4) and thyroid stimulating hormone (TSH) (both boys and girls). For both p,p'-DDE and HCB, a negative association with sexual development in girls was found. The OPP metabolites were negatively associated with sex hormone levels in the blood of boys and with sexual maturation (both boys and girls). The pesticide metabolite 2,5-DCP was negatively correlated with free T4, while a positive association with TSH was reported (boys and girls). These results show that even exposure to relatively low concentrations of pesticides can have significant influences on hormone levels and the degree of sexual maturation in 14-15-year-old adolescents.