Association Between Prenatal Exposure to Per- and Poly-Fluoroalkyl Substances From Electronic Waste Disassembly Areas and Steroid Hormones in Human Milk Samples.

Per- and poly-fluoroalkyl substances (PFAS), which are long-lasting environmental contaminants that are released into the environment during the e-waste disassembly process, pose a threat to human health. Human milk is a complex and dynamic mixture of endogenous and exogenous substances, including steroid hormones and PFAS. Therefore, in this study, we aimed to investigate the association between PFAS and steroid hormones in human milk from women living close to an e-waste disassembly area. In 2021, we collected milk samples from 150 mothers within 4 weeks of delivery and analyzed them via liquid chromatography-tandem mass spectrometry to determine the levels of 21 perfluorinated compounds and five steroid hormones (estrone, estriol, testosterone, progesterone, and androstenedione [A-dione]). We also performed multiple linear regression analysis to clarify the association between maternal PFAS exposure and steroid hormone concentrations. Our results indicated that PFOA and PFOS were positively associated with estrone (ß, 0.23; 95% CI, 0.08-0.39) and A-dione (ß, 0.186; 95% CI, 0.016-0.357) concentrations in human milk, respectively. Further, the average estimated daily intake of PFOA and PFOS were 36.5 ng/kg bw/day (range, 0.52-291.7 ng/kg bw/day) and 5.21 ng/kg bw/day (range, 0.26-32.3 ng/kg bw/day), respectively. Of concern, the PFAS intake of breastfeeding infants in the study area was higher than the recommended threshold. These findings suggested that prenatal exposure to PFAS from the e-waste disassembly process can influence steroid hormones levels in human milk. Increased efforts to mitigate mother and infant exposure to environmental pollutants are also required.

Association between blood lipid levels in early pregnancy and urinary organophosphate metabolites in the Japan Environment and Children's Study.

BACKGROUND: High low-density lipoprotein cholesterol levels (LDL-C) during pregnancy have been associated with adverse pregnancy and offspring outcomes. While previous studies have suggested a potential link between organophosphate pesticide (OPP) exposure and higher LDL-C in the general population and agricultural workers, the relationship in pregnant women and the effect of body mass index on this relationship remain unclear. We examined the association between the urinary concentrations of OPP metabolites (dialkylphosphates) and blood lipid levels in pregnant women. METHODS: We used data from the Japan Environment and Children's Study, which included 5,169 pregnant women with urinary dialkylphosphate data. We examined the association between urinary concentrations of six dialkylphosphates (DEP, DETP, DEDTP, DMP, DMTP, DMDTP) and blood lipid levels (LDL-C, total cholesterol, high-density lipoprotein cholesterol, and triglycerides) during the first trimester using multiple linear regression under a Bayesian paradigm. We examined the association between high LDL-C, defined as ≥90th percentile of LDL-C, and urinary dialkylphosphate concentrations, using multiple logistic regression under a Bayesian paradigm. These analyses were repeated in underweight, normal-weight, and overweight participants. RESULTS: DEP, DMP, and DMTP were detected in >50 % of the participants. Multiple linear regression analyses did not show associations between LDL-C and these dialkylphosphates. Stratified analyses showed a positive association between DEP and LDL-C in overweight women (beta coefficient = 2.13, 95 % credible interval = 0.86-3.38, probability of direction (PD) = 100 %); however, the association was not significant (percentage in region of practical equivalence (% in ROPE) = 84.0). Higher DEP was significantly associated with high LDL-C (odds ratio = 1.32, 95 % credible interval = 1.13-1.55, PD = 100 %, % in ROPE = 0.2). CONCLUSIONS: Among overweight pregnant women in the first trimester, higher urinary DEP concentrations were associated with high LDL-C. The effects of OPP on blood lipid profiles merit further investigation.

Dietary intake of methylmercury by 0-5 years children using the duplicate diet method in Japan.

BACKGROUND: The developing brains are sensitive to methylmercury (MeHg). However, the exposure to MeHg in baby foods and toddler meals remains unknown. This study aimed to determine MeHg intake from baby food or toddler meals, and to investigate the relationship with child hair total mercury (THg). METHODS: A total of 3 days of 24-hour dietary diet and hair samples were collected from 260 consenting children aged 0-5 years. We measured the concentrations of THg and MeHg in the diet and THg in the hair. RESULTS: The results of measuring THg were below both the method detection and method quantification limits or either of both in powdered milk (93.8%), 5-6 months (53.3%), and 7-8 months (39.5%). The median daily THg intake was 20.3 (95% confidence interval 0.72-232.5) ng/kgbw. MeHg was not detected in 213 samples with dietary THg concentrations below 1 ng/g. The MeHg concentration with THg concentrations of 1 ng/g or higher was 1.70 (0.87-6.21) ng/g, and MeHg percentage in THg was 90.0%. To estimate MeHg intake, we multiplied the THg concentration by 90.0%, resulting in an estimated MeHg intake of 18.3 (0.65-209.2) ng/kgbw/day. The THg in children's hair was 1.05 (0.31-3.96) ppm, and a weak positive correlation was observed between hair THg and dietary MeHg (r = 0.170). CONCLUSIONS: This study highlights the accurate estimation of MeHg intake in children using a duplicate method. Japanese children consume fish, the MeHg intakes exceeded the reference dose and/or provisional tolerable weekly intake in several children. Further discussion based on epidemiological data is required.