The occurrence of perfluorinated alkyl compounds in human milk from different regions of China

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 (β, 0.23; 95% CI, 0.08-0.39) and A-dione (β, 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.

Per- and polyfluoroalkyl substances (PFASs) in bivalve molluscs from Shandong Province, China: Occurrence, distribution, and implications for human consumption

We examined the occurrence and levels of 19 legacy and emerging per- and polyfluoroalkyl substances (PFASs) in 7 species of marine bivalve molluscs collected from four coastal cities of Shandong Province, China. Perfluorooctanoic acid (PFOA) was the most prevalent component, accounting for 68.1 % of total PFASs. The total PFASs in bivalve molluscs ranged from 0.86 to 6.55 ng/g wet weight, with the highest concentration found in Meretrix meretrix L. The concentration of total PFASs in bivalve molluscs showed the following trend: clams > scallops > oysters > mussels. Estimation on the human intake of PFASs from consumption of bivalve molluscs resulted in hazard ratios (HR) ranging from 0.12 to 6.40. Five of the seven species had HR >1, indicating high exposure risks associated with PFASs. Therefore, the occurrence of PFASs in marine biota is particularly concerning and further investigations on the sources of PFASs in Shandong are warranted.

Changes in Concentrations of Polyfluoroalkyl Substances in Human Milk Over Lactation Time and Effects of Maternal Exposure via Analysis of Matched Samples

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are potentially related to many adverse health outcomes and could be transferred from maternal blood to human milk, which is an important exposure source for infants during a long-term period. In this study, the maternal blood of 76 women after delivery and their matched human milk samples obtained at 0.5, 1, and 3 months were analyzed by solid-phase extraction method with metal-organic framework/polymer hybrid nanofibers as the sorbents and ultrahigh-performance liquid chromatography-negative electrospray ionization mass spectrometric for quantitative analysis of 31 PFAS. The perfluorooctanoic acid, perfluorooctane sulfonate, and N-methyl perfluorooctane sulfonamido acetic acid (N-MeFOSAA) contributed to more than approximately 50% of the total PFAS concentrations in blood and human milk, while N-MeFOSAA (median: 0.274 ng/mL) was the highest PFAS in human milk at 3 months. The transfer efficiencies for PFAS from maternal blood to human milk at 0.5 months were generally lower, with medians ranging from 0.20% to 16.9%. The number of PFAS species detected in human milk increased as the lactation time went on from 0.5 to 3 months, and the concentrations of 10 PFAS displayed an increasing trend as the prolongation of lactation time (p < 0.05).

Inulin alleviates perfluorooctanoic acid-induced intestinal injury in mice by modulating the PI3K/AKT/mTOR signaling pathway

Perfluorooctanoic acid (PFOA) is a widely used industrial compound that has been found to induce intestinal toxicity. However, the underlying mechanisms have not been fully clarified and effective interventions are rarely developed. Inulin, a prebiotic, has been used as a supplement in human daily life as well as in gastrointestinal diseases and metabolic disorders. In this study, male mice were exposed to PFOA with or without inulin supplementation to investigate the enterotoxicity and potential intervention effects of inulin. Mice were administered PFOA at 1 mg/kg/day, PFOA with inulin at 5 g/kg/day, or Milli-Q water for 12 weeks. Histopathological analysis showed that PFOA caused colon shortening, goblet cell reduction, and inflammatory cell infiltration. The expression of the tight junction proteins ZO-1, occludin and claudin5 significantly decreased, indicating impaired barrier function. According to the RNA-sequencing analysis, PFOA exposure resulted in 917 differentially expressed genes, involving 39 significant pathways, such as TNF signaling and cell cycle pathways. In addition, the protein expression of TNF-α, IRG-47, cyclinB1, and cyclinB2 increased, while Gadd45γ, Lzip, and Jam2 decreased, suggesting the involvement of the TNF signaling pathway, cell cycle, and cell adhesion molecules in PFOA-associated intestinal injury. Inulin intervention alleviated PFOA-induced enterotoxicity by activating the PI3K/AKT/mTOR signaling pathway and increasing the protein expression of Wnt1, β-catenin, PI3K, Akt3, and p62, while suppressing MAP LC3β, TNF-α, and CyclinE expression. These findings suggested that PFOA-induced intestinal injury, including inflammation and tight junction disruption, was mitigated by inulin through modifying the PI3K/AKT/mTOR signaling pathways. Our study provides valuable insights into the enterotoxic effects of PFOA and highlights the potential therapeutic role of inulin.

Per- and polyfluoroalkyl substances (PFAS) in grocery store foods: method optimization, occurrence, and exposure assessment

Dietary exposure to per- and polyfluoroalkyl substances (PFAS) is poorly understood. Evaluating PFAS in food is complicated by the need to evaluate varied matrices and a lack of a standard, matrix-specific sample extraction methods. Prior food studies implemented universal rather than matrix-specific extraction approaches, which may yield false negatives and an underestimation of PFAS dietary exposure if methods are not suitable to all matrices. Here the objectives were to screen and optimize PFAS extraction methods for plants, tissues, and dairy; apply optimized extraction methods to a grocery store food survey; and compare estimated exposure to published reference doses (RfDs). Optimized, matrix-specific extractions generally yielded internal standard recoveries of 50-150% and matrix spike recoveries of 70-130%. The frequency of PFAS detection in grocery store foods (16 of 22 products) was higher than in previous work. PFAS were detected at concentrations of 10 ng kgdw-1 (perfluorobutane sulfonate; washed green beans and perfluorohexanoic acid; unwashed tomato) to 2680 ng kgdw-1 (perfluorohexane sulfonate; radish). Concentrations of perfluorooctanoic acid (PFOA) in carrots, lettuce, radish, and canned green beans yielded median exposure intake (EI) values of 0.016-0.240 ng per kgbw-day, which exceeded the EPA RfD (0.0015 ng per kgbw-day). Washing reduced radish PFOA concentrations below detection, but EIs at the reporting limit still exceeded the RfD. The combination of improved data quality and greater frequency of PFAS detection vs. prior studies plus EI > RfD for some PFAS suggests a need for matrix-specific extractions and analysis of PFAS in additional grocery store foods from broader geographic regions.

Effects of perfluorooctanoic acid (PFOA) on gene expression profiles via nuclear receptors in HepaRG cells: Comparative study with in vitro transactivation assays

Perfluorooctanoic acid (PFOA), a synthetic perfluorinated eight-carbon organic chemical, has been reported to induce hepatotoxicity, including increased liver weight, hepatocellular hypertrophy, necrosis, and increased peroxisome proliferation in rodents. Epidemiological studies have demonstrated associations between serum PFOA levels and various adverse effects. In this study, we investigated the gene expression profiles of human HepaRG cells exposed to 10 and 100 μM PFOA for 24h. Treatment with 10 and 100 μM PFOA significantly modulated the expression of 190 genes and 996 genes, respectively. In particular, genes upregulated or downregulated by 100µM PFOA included peroxisome proliferator-activated receptor (PPAR) signaling genes related to lipid metabolism, adipocyte differentiation, and gluconeogenesis. In addition, we identified the "Nuclear receptors-meta pathways" following the activation of other nuclear receptors: constitutive androstane receptor (CAR), pregnane X receptor (PXR) and farnesoid X receptor (FXR), and the transcription factor, nuclear factor E2-related factor 2 (Nrf2). The expression levels of some target genes (CYP4A11, CYP2B6, CYP3A4, CYP7A1, and GPX2) of these nuclear receptors and Nrf2 were confirmed using quantitative reverse transcription polymerase chain reaction. Next, we performed transactivation assays using COS-7 or HEK293 cells to investigate whether these signaling-pathways were activated by the direct effects of PFOA on human PPARα, CAR, PXR, FXR and Nrf2. PFOA activated PPARα in a concentration-dependent manner, but did not activate CAR, PXR, FXR, or Nrf2. Taken together, these results suggest that PFOA affects the hepatic transcriptomic responses of HepaRG cells through direct activation of PPARα and indirect activation of CAR, PXR FXR and Nrf2. Our finding indicates that PPARα activation found in the "Nuclear receptors-meta pathways" functions as a molecular initiating event for PFOA, and indirect activation of alternative nuclear receptors and Nrf2 also provide important molecular mechanisms in PFOA-induced human hepatotoxicity.

Effects of physicochemical properties and co-existing zinc agrochemicals on the uptake and phytotoxicity of PFOA and GenX in lettuce

Even though the potential toxicity and treatment methods for per- and polyfluoroalkyl substances (PFAS) have attracted extensive attention, the plant uptake and accumulation of PFAS in edible plant tissues as a potential pathway for human exposure received little attention. Our study in a hydroponic system demonstrated that perfluorooctanoic acid (PFOA) and its replacing compound, 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy) propanoic acid (GenX) displayed markedly different patterns of plant uptake and accumulation. For example, the root concentration factor (RCF) of PFOA in lettuce is almost five times of that of GenX while the translocation factor (TF) of GenX is about 66.7% higher than that for PFOA. The co-presence of zinc amendments affected the phyto-effect of these two compounds and their accumulation in plant tissues, and the net effect on their plant accumulation depended on both the properties of Zn amendments and PFAS. Zinc oxide nanoparticles (ZnONPs) at 100 mg/L did not affect the uptake of PFOA in either lettuce roots or shoots; however, Zn2+ at the same concentration significantly increased PFOA accumulation in both tissues. In contrast, both Zn amendments significantly lowered the accumulation of GenX in lettuce roots, but only ZnONPs significantly hindered the GenX accumulation in lettuce shoots. The co-exposure to ZnONPs and PFOA/GenX resulted in lower oxidative stress than the plants exposed to PFOA or GenX alone. However, both zinc agrochemicals with or without PFAS led to lower root dry biomass. The results shed light on the property-dependent plant uptake of PFAS and the potential impact of co-existing nanoagrochemicals and their dissolved ions on plant uptake of PFOA and GenX.

Per- and polyfluoroalkyl substances (PFAS) in breast milk and infant formula: A global issue

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) are transferred from mother to infants through breastfeeding, a time when children may be particularly vulnerable to PFAS-mediated adverse health effects. Infants can also be exposed to PFAS from infant formula consumption. Our recent literature-based scoping of breast milk levels reported that four PFAS often exceeded the United States Agency for Toxic Substances and Disease Registry (ATSDR) children's drinking water screening levels in both the general population and highly impacted communities in the U.S. and Canada. This work presents a comparison of global breast milk and infant formula PFAS measurements with the only reported health-based drinking water screening values specific to children.

METHODS

We focused on four PFAS for which ATSDR has developed children's drinking water screening values: PFOA (perfluorooctanoic acid), PFOS (perfluorooctanesulfonic acid), PFHxS (perfluorohexanesulfonic acid), and PFNA (perfluorononanoic acid). Published literature on PFAS levels in breast milk and infant formula were identified via PubMed searches. Data were compared to children's drinking water screening values.

DISCUSSION

Breast milk concentrations of PFOA and PFOS often exceed children's drinking water screening values, regardless of geographic location. The limited information on infant formula suggests its use does not necessarily result in lower PFAS exposures, especially for formulas reconstituted with drinking water containing PFAS. Unfortunately, individuals generally cannot know whether their infant's exposures exceed children's drinking water screening values. Thus, it is essential that pregnant and lactating women and others, especially those having lived in PFAS-contaminated communities, have data required to make informed decisions on infant nutrition. An international monitoring effort and access to affordable testing are needed for breast milk, drinking water and infant formula to fully understand infant PFAS exposures. Currently, our understanding of demonstrable methods for reducing exposures to emerging PFAS is limited, making this research and the communications surrounding it even more important.

Penetration of Perfluorooctanesulfonate Isomers and Their Alternatives from Maternal Blood to Milk and Its Associations with Chemical Properties and Milk Primary Components

Perfluorooctanesulfonate (PFOS) and its alternatives, including chlorinated polyfluorinated ether sulfonates (Cl-PFESAs), are mainly detected per- and polyfluoroalkyl substances (PFAS) in human samples such as milk. However, the mechanism of their blood to milk transfer was not well studied. Here, 145 paired maternal serum and human milk samples were analyzed for six PFOS isomers and Cl-PFESAs to evaluate the transfer efficiency from maternal serum to human milk (TE_HM/MS). Besides physicochemical properties, this study for the first time evaluated the influencing effects of the primary components in human milk (carbohydrate, lipid, and protein) on TE_HM/MS of PFAS. No significant association was observed between TE_HM/MS and the albumin binding affinity of the compounds (p = 0.601), but TE_HM/MS was significantly negatively correlated with the logarithmic octanol-water partition coefficients (r² = 0.853, p = 0.001), the logarithmic membrane-water partition coefficients (r² = 0.679, p = 0.012), and the carbohydrate contents in human milk. The effect of carbohydrate was further confirmed using in vitro tests. The negative associations between TE_HM/MS and hydrophobicity, membrane passive permeability, and the carbohydrate content in human milk consistently indicated that passive diffusion through the paracellular route might be the main transfer pathway for PFOS and Cl-PFESAs from blood to milk in humans.

Occurrences of legacy and emerging per- and polyfluoroalkyl substances in human milk in China: Results of the third National Human Milk Survey (2017-2020)

Per- and polyfluoroalkyl substances (PFAS) are persistent organic pollutants widely contaminated and exposed in humans. China is a major manufacturer and consumer of these chemicals. To characterize the occurrences, geographical variations, temporal trends, and exposure risks of legacy and emerging PFAS in perinatal women and their children in China, 30 PFAS were measured in 100 pooled human milk samples consisting of 3531 individual samples collected from 100 sites in 24 provinces during the 2017-2020 National Human Milk Survey. Linear-perfluorooctanoic acid (L-PFOA, 151 pg/mL) and linear-perfluorooctane sulfonate (L-PFOS, 57.0 pg/mL) were the predominant PFAS in human milk, followed by 6:2 chlorinated polyfluorinated ether sulfonate (6:2 Cl-PFESA, 25.9 pg/mL). The geographic variation trend of PFOA was different from PFOS and Cl-PFESA, and a special geographic trend of perfluoropentanesulfonate (PFPeS) was observed. Comparison of National Human Milk surveys from different periods showed a sharp decrease of PFAS exposure in old industrial areas including Shanghai and Liaoning, but higher PFAS exposure observed in Shandong and Hubei indicated a possible domestic shift of PFAS manufacture to these areas. Worldwide comparison of PFAS in human milk indicated high PFOA exposure in China. Risk assessments for mothers and breastfeeding infants showed that PFAS exposure is of concern in China.

Perfluorooctanoic Acid and Perfluorooctane Sulfonate in Human Milk: First Survey from Lebanon

Human milk is the primary source of nutrition for infants in their first year of life. Its potential contamination with perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), a group of toxic man-made chemicals, is a health concern that may threatens infants' health. Our study aims to assess the levels of PFOA and PFOS in the breast milk of Lebanese lactating mothers and the maternal factors associated with their presence. High-performance liquid chromatography (HPLC) coupled with a Micromass Quattro micro API triple quadrupole mass spectrometer was used to detect the level of contamination in 57 collected human milk samples. PFOA and PFOS were present in 82.5% and 85.7% of the samples, respectively, while PFOA levels ranged between 120 and 247 pg/mL with a median of 147 pg/mL, and those of PFOS ranged between 12 and 86 pg/mL with a median of 27.5 pg/mL. The median contamination for PFOA exceeded the threshold set by the European Food Safety Authority (EFSA) (60 pg/mL); however, that of PFOS was below the threshold (73 pg/mL). The consumption of bread, pasta, meat, and chicken more than twice per week and that of white tubers and roots at least once per week was significantly associated with higher levels of PFOA (p < 0.05). No significant association was found between maternal age, BMI, parity, level of education, place of residence, source of water used, and smoking with the levels of PFOA and PFOS in the human milk. Additionally, the consumption of cereals at least twice per week was significantly associated with higher levels of PFOS. These findings call for actions to improve the local environmental and agricultural practices, and the regulations and standards for inspecting imported food. It is important to highlight that the benefits of breastfeeding outweigh the reported contamination with PFOS and PFOA in our study.

Breastfed infants' exposure to polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins and dibenzofurans, and per- and polyfluoroalkyl substances: A cross-sectional study of a municipal waste incinerator in China

A municipal waste incinerator (MWI) in Zhejiang, China, operating since 2008 was completely reconstructed from 2016 to 2019. In 2013, we conducted a cross-sectional study of breastfeeding mothers living near the MWI. We evaluated the concentrations of polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the mothers' breast milk and their infants' estimated daily intake (EDI). To investigate the temporal variations of these pollutants, we conducted a cross-sectional study of 29 mothers in 2019. We assessed the levels of 18 PCB congeners, 17 PCDD/F congeners, and 21 per- and polyfluoroalkyl substance (PFAS) congeners in breast milk and estimated the EDI. The mean total concentrations of PCDD/Fs (ΣPCDD/Fs) and PCBs (ΣPCBs) were 81.2 and 4.90 ng/g lipid, respectively, while the toxic equivalent quantity (TEQ) levels of ΣPCDD/Fs and dioxin-like PCBs (ΣDL-PCBs) were 2.7 and 1.4 pg WHO-TEQ/g lipid, respectively. Compared to our 2013 measurements, the mass concentrations of ΣPCDD/Fs and ΣPCBs decreased by 13% and 35%, respectively (3.361 vs. 2.915 pg/g wet weight [ww] and 269.1 vs. 175.0 pg/g ww, respectively). The TEQ-ΣPCDD/F levels decreased by 67% (0.241 vs. 0.080 pg/g ww), but the TEQ-ΣDL-PCB levels increased by 11% (0.046 vs. 0.051 pg WHO-TEQ/g ww). The median concentration of PFASs was 0.250 ng/mL, ranging from 0.151 to 0.833 ng/mL. The infants' mean EDI of total PCDD/Fs and DL-PCBs was 17.7 pg TEQ/kg body weight [bw], representing a 20% decline compared to 2013. The average EDI levels of PFOS, PFOA, and PFNA were 5.8, 17.9, and 1.7 ng/kg bw, respectively. A comprehensive comparison of the results with studies from around the world showed that the potential health risks posed by legacy PCDD/F and PCB pollutants were not as grave for mothers and infants living near this MWI, but the emerging PFAS pollutants represented a new cause for concern. MAIN FINDINGS: The potential health risks posed by legacy PCDD/F and PCB pollutants were not particularly serious for mothers and infants living near the MWI, but the emerging PFAS pollutants raised new concerns.

Perfluoroalkyl acids in representative edible aquatic species from the lower Yangtze River: Occurrence, distribution, sources, and health risk

Perfluoroalkyl acid (PFAA) exposure poses a potential hazard to wildlife and humans. Food consumption is one of the main routes of PFAA exposure for the general population, with aquatic organisms being the major contributors. To evaluate the risk of coastal residents' intake of wild aquatic organisms, 14 PFAAs were detected in crucian carp and oriental river prawn from 18 sampling sites from the lower reaches of Yangtze River. The total PFAA (∑PFAA) concentrations ranged from 5.9 to 51.3 ng/g wet weight (ww) in the muscle of crucian carp and river prawn, suggesting the potential risk to human and wildlife. Perfluorooctanesulfonate (PFOS), perfluorooctanoic acid (PFOA) and long-chain PFAAs (C ≥ 10) were the main pollutants in the tissues of crucian carp and river prawn, which are known for their higher bioaccumulation capacity. The ∑PFAA concentration in all the samples showed an increasing trend from upstream to downstream and was higher in the south bank, owing to population density, prevailing winds, background pollution and industrial emission. Principal component analysis-multiple linear regression and Pearson correlation analysis showed that WWTP effluent, industrial pollution and surface runoff ware the main sources of PFAAs in the aquatic organisms and industrial pollution highest contributor, suggesting better regulation is needed to manage them. The assessment of risk to human health and wild life suggested a low risk for most residents of cities along the Yangtze River except for resident of Nantong, where frequent consumption of wild aquatic organisms may cause potential risk to human health, especially for traditional eaters and middle-aged people.

Perfluorinated alkyl substances in Canadian human milk as part of the Maternal-Infant Research on Environmental Chemicals (MIREC) study

Perfluorinated alkyl substances (PFAS) were determined in human milk samples (n = 664) from participants in the Maternal-Infant Research on Environmental Chemicals (MIREC) study. ΣPFAS concentrations (sum of seven PFAS) ranged from 3.1 ng L^-1 to 603 ng L^-1, with a median concentration of 106 ng L^-1 in the Canadian mothers' milk analyzed. These data comprise the first pan-Canadian dataset of PFAS in human milk. Perfluorooctanoic acid (PFOA) and linear perfluorooctanesulfonate (L-PFOS) were the dominant contributors to ΣPFAS in human milk samples. An inverse relationship between ΣPFAS concentrations and age was observed (Spearman correlation - 0.184). Primiparous women had elevated PFAS concentrations in milk relative to women who had children previously (p < 0.001). In contrast, the region of maternal birth did not influence ΣPFAS concentrations (p = 0.156). Although China and Norway have observed consistently detectable levels of perfluoroundecanoic acid (PFUdA) in human milk, PFAS with long carbon chains (n ≥ 11) were not present above method detection limits in Canadian human milk samples analyzed as part of the MIREC study. In conclusion, despite the presence of low levels of environmental contaminants in human milk, Health Canada supports breastfeeding due to the benefits to both infants and mothers.

Polychlorinated dioxins and dibenzofurans (PCDD/F), polybrominated dioxins and dibenzofurans (PBDD/F), polychlorinated biphenyls (PCB), polybrominated diphenyl ethers (PBDE), and per- and polyfluoroalkyl substances (PFAS) in German breast milk samples (LUPE 8)

Most organic pollutants (POP) are persistent in the environment, accumulate in fatty tissues, and so a transfer through the food chain is probably, thereby causing various health effects. We quantified PCDD/F, PBDD/F, PCB, PBDE, perfluorinated substances, and ADONA in breast milk samples collected in two German federal states and breast milk and blood samples from subjects additionally exposed to PFOA. The median (95th percentile) concentrations were 2.43 (6.58) pgWHO₂₀₀₅TEQ/g l.w. for PCDD/F, 2.45 (4.82) pgWHO₂₀₀₅TEQ/g l.w. for dioxin-like PCB (dl-PCB), and 0.62 (2.69) pgWHO₂₀₀₅TEQ/g l.w. for PBDD/F. The relative contributions of the median values of PCDD/F, dl-PCB, and PBDD/F to the total-TEQ were approximately 41%, 42%, and 11%, respectively. Nondioxin-like PCB (ndl-PCB) concentrations were clearly dominated by the higher chlorinated PCB congeners, with medians of 23.2 ng/g l.w. for PCB 153, 13.9 ng/g l.w. for PCB 138, and 13.0 ng/g l.w. for PCB 180. The sum of the 3 congeners (PCB 138, 153, and 180) were multiplied with 1.64 (total PCB) and showed a median of 82.16 ng/g l.w. and a 95th percentile of 173.3 ng/g l.w. Only PFOA and PFOS could be quantified in 29% and 17% of in total 180 samples with 95th percentiles of 53 ng/l and 33 ng/l, respectively. Milk samples (n = 13) from subjects living on PFOA contaminated sites showed higher levels between 33 and 854 ng/l PFOA (mean: 199 ng/l), whilst PFOS could be quantified only in three samples. The sum of 17 PBDE congeners showed medians (95th percentile) of 1737 pg/g l.w. (22,806 pg/g l.w.), with the highest medians of 422 pg/g l.w. for BDE 209 and 378 pg/g l.w. for BDE 153. Overall, our study confirms the declining contamination level in breast milk during the last decade, but points out the need to further reduce the environmental contamination with persistent substances and subsequently the exposure in childhood.

Prenatal and postnatal exposure to emerging and legacy per-/polyfluoroalkyl substances: Levels and transfer in maternal serum, cord serum, and breast milk

Gestation and lactation are critical and vulnerable stages for fetuses and newborns. During these periods, per-/polyfluoroalkyl substances (PFASs) accumulated in mothers can be transferred to newborns through placenta and/or breastfeeding, causing potential health risks. To investigate the pre- and postnatal PFAS exposure of newborns, we analyzed 21 emerging and legacy PFASs in 60 sets of matched maternal serum, cord serum, and breast milk samples. In serum, perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), and 6:2 chlorinated polyfluorinated ether sulfonates (6:2 Cl-PFESA) were the most predominant PFASs, while PFOA, PFOS and 6:2 fluorotelomer phosphate diester (6:2 diPAP) contributed most to breast milk. For most PFASs, the levels followed the order of maternal serum > cord serum > breast milk. The 6:2 Cl-PFESA was positively associated with birth weight and ponderal index (p < 0.05). The breastfeeding transfer efficiencies (R_BM, median: 0.02-0.10) of most PFASs were 1-2 orders of magnitude lower than transplacental transfer efficiencies (R_CM, median: 0.40-1.45), except for perfluorobutanesulfonic acid (PFBS) showing high transfer efficiency both through placenta (median at 0.89) and breastfeeding (median at 0.86). The one-month postnatal exposure to PFASs via breastfeeding was much higher than prenatal exposure in utero. This study enhances the understanding of transplacental and breastfeeding transfer of PFASs and provides assessments of prenatal and postnatal exposure of newborns to emerging and legacy PFASs.

Association of maternal exposure to perfluoroalkyl and polyfluroalkyl substances with infant growth from birth to 12 months: A prospective cohort study

BACKGROUND

Although maternal perfluoroalkyl and polyfluroalkyl substances (PFASs) were associated with adverse birth outcomes, much less is known about their impact on infant growth during early infancy.

OBJECTIVES

We investigated the association between maternal PFASs exposure and infant growth during the first 12 months of life.

METHODS

Participating 2395 pregnancies were recruited from Shanghai Birth Cohort between 2013 and 2016. Ten PFASs were quantified from maternal plasma collected during early pregnancy (median, 15 gestational weeks). We measured infant length, weight, and head circumference at birth, 42 days, 6 months, and 12 months. Linear mixed regression model was used to estimate the associations between PFAS concentrations and repeated measurements of infant growth. Effect modification by infant sex was estimated.

RESULTS

Elevated perfluoroheptanoic acid (PFHpA) concentration was negatively associated with infant length-for-age Z score (LAZ) (β = -0.06, 95% confidence interval (CI): -0.11, -0.01) during the first year. Adverse associations were also observed for perfluorobutane sulfonate (PFBS) and weight-for-length Z score (WFL) (β = -0.02, 95% CI: -0.04, -0.00) and BMI-for-age Z score (BAZ) (β = -0.02, 95% CI: -0.04, -0.00). However, perfluorododecanoic acid (PFDoA) was positively associated with WFL (β = 0.03, 95% CI: 0.00, 0.06) and BAZ (β = 0.03, 95% CI: 0.00, 0.06). The adverse association of PFHpA and LAZ was more pronounced among males (β = -0.06; 95% CI: -0.11, -0.00) than females (β = 0.06; 95% CI: 0.01, 0.12).

CONCLUSIONS

In our study, negative associations were found for maternal PFHpA exposure and infant LAZ, PFBS and WFL and BAZ. Meanwhile, maternal PFDoA exposure was positively related with WFL and BAZ. The adverse association of maternal PFHpA exposure and infant LAZ was more pronounced among males. The results should be interpreted with caution, further prospective cohort studies with longitudinal and detailed measures are warranted to confirm these findings.

Immunotoxicity of F53B, an alternative to PFOS, on zebrafish (Danio rerio) at different early life stages

As an alternative to perfluorooctane sulfonate (PFOS), 6:2 chlorinated polyfluorinated ether sulfonate (F53B) has emerged in the Chinese market in recent years and has been frequently detected in the aquatic environment, but its ecological risk assessment is limited. In this study, zebrafish embryos and larvae were separately exposed to F53B, and their 96-h LC₅₀ values were estimated to be 15.1 mg/L and 2.4 mg/L, respectively, suggesting that embryos were more resistant to F53B than larvae. The bioconcentration factor in larvae was basically higher than that of embryos, and the body growth of larvae was significantly affected by F53B rather than embryos, indicating that F53B may cause more severe toxicity to larvae. In addition to the excessive production of ROS and NO, the expression of many immune-related genes was increased in both embryos and larvae, but the number of dysregulated genes in larvae was more than that in embryos. Finally, the results of Point of Departure (PoD) indicated that the immunotoxicity of F53B was more sensitive to larvae than embryos at the molecular level. Our findings revealed the ecological risk of F53B by exploring the adverse effects of immunoregulation at different early life stages of zebrafish and indicated that the zebrafish larvae were more sensitive than embryos.

Regional occurrence of perfluoroalkane substances in human milk for the global monitoring plan under the Stockholm Convention on Persistent Organic Pollutants during 2016-2019

The human milk monitoring component of the global monitoring plan under the Stockholm Convention on Persistent Organic Pollutants was implemented from 2016 to 2019 and had 44 human milk samples from primiparae collected in 42 countries and analyzed for perfluoroalkane substances (PFAS), at the MTM Research Centre at Örebro University, Sweden. The targeted compounds were restricted to the two listed PFAS (perfluorooctane sulfonic acid, PFOS and perfluorooctane carboxylic acid, PFOA) and the one recommended PFAS (perfluorohexane sulfonic acid, PFHxS). PFOA was quantified in all 44 samples in a quite narrow range (6.20 pg/g-37.4 pg/g); PFHxS was quantifiable in only four samples (max. 111 pg/g), and PFOS in 36 samples across a wide range (<6.2 pg/g-212 pg/g). Branched PFOS isomers on average had a share of 16% of the total PFOS with a maximum of 33%. PFOS was highly correlated with PFHxS (Pearson correlation coefficient R = 0.95) and weakly but still positively with PFOA (R = 0.44). Statistical analysis (all on p<0.05) showed that PFOS and PFOA in European countries were significantly different from those in African and Latin American countries and between high-income and low-income countries. PFOA tends to have higher concentrations in wealthier countries. No correlation was found for population density.

Concentrations of perfluoroalkyl substances in donor breast milk in Southern Spain and their potential determinants

BACKGROUND

Breast milk is considered to offer the best nutrition to infants; however, it may be a source of exposure to environmental chemicals such as perfluoroalkyl compounds (PFAS) for breastfeeding infants. PFAS are a complex group of synthetic chemicals whose high stability has led to their ubiquitous contamination of the environment.

OBJECTIVE

To assess the concentrations and profiles of PFAS in breast milk from donors to a human milk bank and explore factors potentially related to this exposure.

METHODS

Pooled milk samples were collected from 82 donors to the Human Milk Bank of the Virgen de las Nieves University Hospital (Granada, Spain). Ultra-high performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS) was applied to determine milk concentrations of 11 PFAS, including long-chain and short-chain compounds. A questionnaire was used to collect information on donors' socio-demographic characteristics, lifestyle, diet, and use of personal care products (PCPs). Factors related to individual and total PFAS concentrations were evaluated by multivariate regression analysis.

RESULTS

PFAS were detected in 24-100% of breast milk samples. PFHpA was detected in 100% of samples, followed by PFOA (84%), PFNA (71%), PFHxA (66%), and PFTrDA (62%). Perfluorooctane sulfonate (PFOS) was detected in only 34% of donors. The median concentrations ranged from <0.66 ng/dL (perfluorohexane sulfonic acid [PFHxS]) to 19.39 ng/L (PFHpA). The median of the sum of PFAS concentrations was 87.67 ng/L and was higher for short-chain than long-chain PFAS. Factors most frequently associated with increased PFAS concentrations included intake of creatin animal food items and use of PCPs such as skin care and makeup products.

CONCLUSIONS

Several PFAS, including short-chain compounds, are detected in pooled donor milk samples. Breast milk may be an important pathway for the PFAS exposure of breastfed infants, including preterm infants in NICUs. Despite the reduced sample size, these data suggest that various lifestyle factors influence PFAS concentrations, highlighting the use of PCPs.

Per- and Polyfluoroalkyl Substances (PFAS) in Breast Milk: Concerning Trends for Current-Use PFAS

This is the first study in the last 15 years to analyze per- and polyfluoroalkyl substances (PFAS) in breast milk collected from mothers (n = 50) in the United States, and our findings indicate that both legacy and current-use PFAS now contaminate breast milk, exposing nursing infants. Breast milk was analyzed for 39 PFAS, including 9 short-chain and 30 long-chain compounds, and 16 of these PFAS were detected in 4-100% of the samples. The ∑PFAS concentration in breast milk ranged from 52.0 to 1850 pg/mL with a median concentration of 121 pg/mL. Perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) were the most abundant PFAS in these samples (medians 30.4 and 13.9 pg/mL, respectively). Two short-chain PFAS, including perfluoro-n-hexanoic acid (PFHxA, C6) and perfluoro-n-heptanoic acid (PFHpA, C7), were detected in most of the samples with median concentrations of 9.69 and 6.10 pg/mL, respectively. Analysis of the available breast milk PFAS data from around the world over the period of 1996-2019 showed that while the levels of the phased-out PFOS and PFOA have been declining with halving times of 8.1 and 17 years, respectively, the detection frequencies of current-use short-chain PFAS have been increasing with a doubling time of 4.1 years.

Male reproductive toxicity of perfluorooctanoate (PFOA): Rodent studies

Perfluorooctanoic acid (PFOA) is an artificial organic substance widely used for decades, which seriously threatens human health. This study aimed to identify human-relevant correlates between PFOA exposure and the male rodent reproductive system. We performed a systematic literature review of the relevant literature of PubMed, Cochrane Library databases, Web of Science and Embase from the establishment to April 2020. Studies included the effects of PFOA on the reproductive system of male rodents. The meta-analysis was performed on the basis of the following points: level of testosterone and estradiol in serum, development of reproductive organs, pathological changes of reproduction organs and parameters of semen. A series of 16 studies was enrolled in this study. The standard mean difference (SMD) for PFOA-related reproductive toxicity was summarised as -0.39 (95% confidence interval [CI]: 0.71, -0.07). The lower serum testosterone levels, decreased absolute testicular and epididymal weights, higher serum estradiol levels, elevated relative testicular and seminal vesicle weights and increased incidence of Leydig cell adenoma and percentage of abnormal sperm were observed in the exposed group compared with the control group. However, no statistical difference was found in the day of preputial separation of pups and percentage of motile sperm. In conclusion, PFOA exposure heightens the reproductive system damage in male rodents. However, many studies included in the review did not identify mechanisms by which PFOA induces changes to the male reproductive system, which is an area for additional study.

Determination and assessment of human dietary intake of per and polyfluoroalkyl substances in retail dairy milk and infant formula from South Africa

Dairy milk and infant formula play important roles in the diet of adolescents, adults and infants, respectively, in the South African population. However, data on the occurrence of legacy and emerging contaminants such as PFAS in these important food sources is lacking. In this study, the concentration of fifteen PFAS were measured in 23 pooled retail dairy milk and 7 pooled infant formulas by means of an ultrahigh performance liquid chromatography tandem mass spectrometric method. The concentrations of Σ₁₅PFAS ranged from 0.08-15.51 ng mL^-1 and 0.42-5.74 ng mL^-1 in dairy milk and infant formulas, respectively. PFBA, PFPeA, PFuDA, PFTrDA and PFDoA were the most prevalent PFAS in both matrices with detection frequency > 96%. Highest PFAS concentrations of 2.02 ng ml^-1 and 2.76 ng ml^-1 were recorded for PFDoA in infant formulas and dairy milk, respectively. The concentrations of legacy PFAS -PFOA and PFOS, shows resemblance with global data, however, elevated concentrations of long chain C₉ - C₁₄ PFAS were observed in this study. Though, higher concentrations of PFAS were measured in full cream dairy milk, no statistical significant difference (P = 0.546) was observed for the various classes of dairy milk. The EDI of Σ₁₅PFAS through infant formulas were 184.92, 329.47 and 166 ngkg^-1BWday^-1 for partially breastfed, exclusively formula fed and older infants, respectively. Similarly, the EDI of PFAS through dairy milk for toddlers, adolescents, female and male adults for the rural population were 14.17, 1.09, 2.59 and 3.16 ngkg^-1BWday^-1 respectively while they were 20.41, 3.84, 4.13 and 4.26 ngkg^-1BWday^-1 respectively in the urban population. Although, the EDI of PFAS through the consumption of infant formulas and dairy milk are lower than the daily tolerable limits, the relative importance of long-term exposure and the cumulative effects of multiple exposure pathways cannot be overemphasized.

Levels and profiles of persistent organic pollutants in breast milk in China and their potential health risks to breastfed infants: A review

Although some persistent organic pollutants (POPs) were prohibited or limited in use several decades ago, they are still frequently detected in the human body. The purpose of this study was to understand the levels and profiles of POPs in breast milk in China and assess their potential health risks among breastfed infants under six months of age. A literature review focused on China was performed for studies published from 2001 to 2020. The POP levels in breast milk along with other important variables were extracted, and then the average individual POP levels in breast milk were estimated. This review summarises the distribution of traditional and new POPs, including polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), legacy brominated flame retardants (BFRs), perfluorinated compounds (PFCs), and chlorinated paraffins (CPs) and reported notably high levels of short-chain chlorinated paraffins and 1,1-dichloro-2,2-bis (p-chlorophenyl) ethylene (p,p'-DDE) in breast milk. Although the levels of traditional POPs generally declined over time, especially p,p'-DDE and beta-hexachlorocyclohexane (β-HCH), women living in coastal areas, urban areas, and southern China still have a high body burden of certain POPs. In the present study, the estimated daily intake (EDI) of POPs through breastfeeding was used to evaluate the health risk for infants by comparing with acceptable levels. The findings suggested that infants born in coastal areas most likely suffered potential health risk from exposure to DDT, and the health risk of hexachlorobenzene (HCB) in infants in most nationwide regions remains a concern. More importantly, the EDI of PCBs for infants exceeds the safe limit on a national scale. Continuous surveillance of PCBs in breast milk is critical to evaluate the potential health effects on humans.

Per- and polyfluoroalkyl substances (PFASs) in contaminated coastal marine waters of the Saudi Arabian Red Sea: a baseline study

Per- and polyfluoroalkyl substances (PFASs) are today considered important constituents of the continuously growing substance group of persistent contaminants of emerging environmental concern (PCEC). Here, we report for the first time the concentrations of 12 relevant PFASs in 28 marine water samples from the Saudi Arabian coastal waters of the Red Sea. The sum levels of 12 PFASs (Σ₁₂ PFAS) in surface seawater ranged from <LOQ to 956 ngL^-1. For the reference background site of this study, Σ₁₂ PFAS levels ranged from <LOQ to 10.9 ng/L. The highest PFAS levels have been found in Al-Arbaeen and Al-Shabab, two lagoons continuously receiving treated sewage effluents. PFHxA, PFHxS, and 6:2 FTS were the most prevalent PFASs with relatively high concentrations. Discharge of municipal and industrial wastewaters is considered an important source of PFASs. The pattern of PFASs observed here suggests that the usage of PFAS-containing aqueous film-forming foams (AFFFs) is a potential additional source for these compounds in Al-Arbaeen and Al-Shabab lagoons. However, a systematic elucidation of local PFASs sources is needed. Contamination of the Red Sea waters with PFASs poses a potential imminent risk to the marine environment of the Red Sea and ultimately may even affect the health of human consumers through the consumption of local seafood.

Novel Perfluoroalkyl Ether Carboxylic Acids (PFECAs) and Sulfonic Acids (PFESAs): Occurrence and Association with Serum Biochemical Parameters in Residents Living Near a Fluorochemical Plant in China

Although perfluoroalkyl ether carboxylic (PFECAs) and sulfonic acids (PFESAs) have been widely detected in environmental matrices, their occurrence in humans and impact on human health remains insufficiently understood. Here, we report on 13 PFECAs and PFESAs in 977 sera samples collected from residents living near a fluorochemical plant in Shandong, China. The sum concentration of these emerging PFECAs accounted for 13% of the total PFASs in the serum of the participants, with the frequent detection of several PFECAs (>95%) (PFMOAA, PFO4DA, and PFO5DoDA at median concentrations of 12.91, 0.142, and 0.987 ng/mL, respectively) and PFESAs (98.7%) (Nafion byproduct 2 at a median concentration of 0.097 ng/mL). Serum PFMOAA, PFO5DoDA, and 6:2 Cl-PFESA levels were significantly higher in males than in females. Positive relationships were observed between age and PFMOAA, 6:2 Cl-PFESA, and H-PFMO2OSA levels, whereas HFPO-TA and PFO5DoDA serum concentrations in the 0-40-year age group were lower than that in the >40-year age group. Furthermore, multivariate linear regression models and sensitivity analyses showed positive associations among PFO5DoDA levels, elevated lipid parameters (cholesterol, low-density lipoprotein cholesterol, and triglycerides), liver function markers (albumin levels and alanine transaminase, aspartate aminotransferase, and glutamyl transpeptidase activities), and uric acid levels. Thus, our results suggest potential health risks from exposure to novel PFESAs and PFECAs (especially PFO5DoDA).

Exposure characteristics for congeners, isomers, and enantiomers of perfluoroalkyl substances in mothers and infants

Per- and polyfluoroalkyl substances (PFASs) are ubiquitous in the environment, making it inevitable for humans to be exposed to these pollutants. The exposure begins while in utero and continues in infancy, during the potentially most sensitive early stages of life. This review summarizes the current knowledge on pre- and neo-natal exposures based on more than 200 articles published from 2000 to date. All relevant biological matrices used in the cited studies were included, such as maternal blood, umbilical cord blood, breast milk, placenta, amniotic fluid, fetal organs, newborns' dried blood spots, and infant serum. We show that such exposures are geographically global with significant discrepancies among countries and continents, and that while the levels of major legacy PFASs (PFOS and PFOA) have declined since 2000, those of others may have not. We also show that levels of PFOS and PFOA exceed those of some major environmental toxins, such as p,p'-DDE, BDE-47, PCB-153, PBB-153, and OH-PBDEs in maternal blood. Given that the behavior and potential effects have an origin in molecular structure, biomonitoring and research at the levels of isomers and enantiomers are critically important. Through critical analysis of these works, we summarize the major achievements, consensus, and the deficiencies of existing research. To our knowledge, this is the first review on the overall internal exposure status of mothers and infants to PFASs during pregnancy and lactation.

Exposure to elevated per- and polyfluoroalkyl substances in early pregnancy is related to increased risk of gestational diabetes mellitus: A nested case-control study in Shanghai, China

BACKGROUND

Long-chain per- and polyfluoroalkyl substances (PFASs) and their short-chain alternatives have been produced and used extensively in China. However, it is unclear whether these compounds contribute to the risk of gestational diabetes mellitus (GDM) in women residing in contaminated areas.

OBJECTIVE

The study was performed to explore the association between PFASs varying in chain length and the risk of developing GDM.

METHOD

A nested case-control study was conducted in a prospective cohort of 2,460 pregnant women between July 1, 2017, and January 31, 2019 in Shanghai, China. Twelve PFASs of interest were measured using ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC-Q/TOF MS) in the sera of pregnant women at 16-20 weeks. GDM was diagnosed by an oral glucose tolerance test administered over 24-28 gestational weeks. The cases and controls were matched by maternal age. The relationship between maternal serum PFAS level and GDM risk was determined by conditional logistic and linear regression analyses.

RESULTS

A total of 165 GDM cases and 330 controls were enrolled in the study cohort. The frequencies of detection of PFHpA, PFDS, and PFOSA were all ≤80%. Hence, they were excluded from any further risk analysis. Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) were detected at relatively high serum levels (medians 6.57 ng/mL and 8.07 ng/mL, respectively). The serum levels of perfluorobutanesulfonic acid (PFBS) and perfluorododecanoic acid (PFDoA) were significantly higher in the GDM group than they were in the control group (P = 0.02 and P < 0.01, respectively) according to a nonparametric Wilcoxon rank sum test. A quartile analysis showed that the odds ratio of GDM would significantly increase at the highest PFBS and PFDoA levels. In the core model, the adjusted ORs were 2.02 (95% CI = 1.04-3.79) and 13.00 (95% CI = 4.74-24.59), respectively, after adjusting for maternal age, sampling time, parity and body mass index [BMI]).

CONCLUSION

Elevated maternal serum PFBS and PFDoA levels in early pregnancy may be associated with a substantially higher GDM risk.

Emerging per- and polyfluoroalkyl substances (PFAS) in human milk from Sweden and China

Twenty per- and polyfluoroalkyl substances (PFAS) were determined in human milk from residents of three Chinese cities (Shanghai, Jiaxing, and Shaoxing; [n = 10 individuals per city]), sampled between 2010 and 2016. These data were compared to a combination of new and previously reported PFAS concentrations in human milk from Stockholm, Sweden, collected in 2016 (n = 10 individuals). Across the three Chinese cities, perfluorooctanoate (PFOA; sum isomers), 9-chlorohexadecafluoro-3-oxanone-1-sulfonic acid (9Cl-PF3ONS; also known as 6:2 Cl-PFESA or by its trade name "F53-B"), and perfluorooctane sulfonate (PFOS; sum isomers) occurred at the highest concentrations among all PFAS (up to 411, 976, and 321 pg mL^-1, respectively), while in Stockholm, PFOA and PFOS were dominant (up to 89 and 72 pg mL^-1, respectively). 3H-Perfluoro-3-[(3-methoxy-propoxy)propanoic acid] (ADONA) was intermittently detected but at concentrations below the method quantification limit (i.e. <10 pg mL^-1) in Chinese samples, and was non-detectable in Swedish milk. The extremely high concentrations of F53-B in Chinese milk suggest that human exposure assessments focused only on legacy substances may severely underestimate overall PFAS exposure in breastfeeding infants.

HPLC-MS/MS method for the determination of perfluoroalkyl substances in breast milk by combining salt-assisted and dispersive liquid-liquid microextraction

The widespread use of perfluoroalkyl substances has resulted in the universal exposure of humans to these endocrine-disrupting chemicals, including the exposure of neonates through breastfeeding. The objective of this study was to develop a method to determine 10 perfluoroalkyl substances in breast milk (1-mL aliquot) by combining salt-assisted liquid-liquid extraction with dispersive liquid-liquid microextraction and using high-performance liquid chromatography-tandem mass spectrometry. Chemometric strategies were applied to optimize experimental parameters. The limit of quantification was 20 pg mL^-1 for all analytes, and inter-day variability (evaluated as relative standard deviation) ranged from 8.2 to 13.8%. The method was validated by a recovery assay with spiked samples. Percentage recoveries ranged from 85.9 to 110.8%. The method was satisfactorily applied to assess target compounds in 20 breast milk samples from donors. Perfluorooctanoic acid, perfluorooctane sulfonate, and perfluorohexanoic acid were the most frequently detected analytes. This analytical procedure can provide useful information on newborn's exposure to these xenobiotics.

Effect of PFOA on DNA Methylation and Alternative Splicing in Mouse Liver

Perfluorooctanoic acid (PFOA) is a persistent organic pollutant prevalent in the environment and implicated in damage to the liver leading to a fatty liver phenotype called hepatocellular steatosis. Our goal is to provide a basis for PFOA-induced hepatocellular steatosis in relation to epigenetic alterations and mRNA splicing. Young adult female mice exposed to different concentrations of PFOA showed an increase in liver weight with decreased global DNA methylation (5-mC). At higher concentrations, the expression of DNA methyltransferase 3A (Dnmt3a) was significantly reduced and the expression of tet methycytosine dioxygenase 1 (Tet1) was significantly increased. There was no significant change in the other Dnmts and Tets. PFOA exposure significantly increased the expression of cell cycle regulators and anti-apoptotic genes. The expression of multiple genes involved in mTOR (mammalian target of rapamycin) signaling pathway were altered significantly with reduction in Pten (phosphatase and tensin homolog, primary inhibitor of mTOR pathway) expression. Multiple splicing factors whose protein but not mRNA levels affected by PFOA exposure were identified. The changes in protein abundance of the splicing factors was also reflected in altered splicing pattern of their target genes, which provided new insights on the previously unexplored mechanisms of PFOA-mediated hepatotoxicity and pathogenesis.

Poly- and perfluoroalkyl substance concentrations in human breast milk and their associations with postnatal infant growth

Perfluoroalkyl carboxylates (PFCAs) and perfluoroalkyl sulfonates are widespread in human breast milk. However, the occurrence of chlorinated polyfluorinated ether sulfonates (Cl-PFESAs) and fluorotelomer alcohols (FTOHs) in breast milk and their effects on postnatal growth of infants through breast milk consumption are still not well known. This study characterized the occurrence of 16 poly- and perfluoroalkyl substances (PFASs) in breast milk from 174 women in Hangzhou, China and investigated the association between lactation exposure to these PFASs through breast milk consumption and the postnatal growth of infants. Our results showed that perfluorooctanoate (mean 87 pg/mL) was the predominant PFAS in breast milk, followed by perfluorohexanoate (41 pg/mL), 6:2 Cl-PFESA (28 pg/mL), and perfluorooctane sulfonate (25 pg/mL). The occurrence and levels of Cl-PFESAs in Chinese breast milk were firstly reported in the current study. The 8:2 and 10:2 FTOH were detected in half of breast milk samples, with the mean concentration of 9.0 pg/mL and 10 pg/mL, respectively. Breast milk concentrations of C₈-C₁₀ PFCAs and 6:2 Cl-PFESA were negatively correlated with infant's length gain rate. Exposed to higher levels of 8:2 FTOH were correlated with decreased infant's weight gain rate. Daily intakes of PFASs via the consumption of breast milk were calculated for infants. Overall, this study firstly demonstrated that lactation exposure to C₈-C₁₀ PFCAs, 8:2 FTOH, and 6:2 Cl-PFESA through breast milk consumption may affect the postnatal growth of infants.

Dietary Exposure of Chinese Adults to Perfluoroalkyl Acids via Animal-Origin Foods: Chinese Total Diet Study (2005-2007 and 2011-2013)

Diet has been regarded as the main exposure source of perfluoroalkyl acids (PFAAs), but the national dietary survey of PFAAs in China was limited. Here, eight typical PFAAs were detected in milk, aquatic food, meat, and eggs from the Chinese Total Diet Studies (TDSs) during 2005-2007 and 2011-2013. Aquatic food was found to be the main source of PFAAs among animal-origin foods. The estimated dietary intakes of ∑PFAAs from animal foods (EDI_{animal-origin foods}) in coastal areas were relatively higher than in inland areas. The highest EDI_{animal-origin foods} of PFOS [4.07 and 2.02 ng kg^-1 of body weight (bw) day^-1] and PFOA (2.19 ng kg^-1 of bw day^-1) found in Shanghai and perfluorononanoic acid (PFNA, 2.72 ng kg^-1 of bw day^-1) in Fujian approach or exceed current minimal risk levels from the Agency for Toxic Substances and Disease Registry and tolerable weekly intakes from the European Food Safety Authority, suggesting potential risk of PFAA exposure from animal-origin foods in these areas.

Per- and polyfluoroalkyl substances in human breast milk and current analytical methods

Per- and polyfluoroalkyl substances (PFASs) have since become a major health concern as they have been reportedly found in human tissues, blood and breast milk. The main aim of the study was to review the current data on PFASs in human breast milk, including the challenges of analysis as well as the possible modes of transfer from maternal blood. In this paper, previously published data on the concentrations of PFASs in human breast milk from around the world were reviewed and summarised. Eligible studies with reference lists published before 1 June 2017 were included by searching several databases (including Scopus, ScienceOpen and SciFinder). From this search, studies with the number of participants in each study ranging from 2 to 1237 were identified. The review indicated that based on the structural profiles and concentration levels, there was variation in the geographical distribution of these compounds in breast milk. Although there are no recorded investigations on the modes of transfer from maternal blood to breast milk, literature suggests that the PFASs tend to be transferred through binding to various proteins. The review also examined the different sample preparation and analytical methods employed to measure the concentrations of PFASs in human breast milk. This showed that solid phase extraction was the most common extraction method. After extraction, liquid chromatography coupled with tandem mass spectrometry was the most common analysis method. Since several of these methods were initially dedicated to monitoring PFASs in food and water, they demonstrate some limitations with regard to specificity and sensitivity to human fluids. Additionally, there are currently no published records of certified reference materials and/or proficiency scheme devoted to standardising PFAS concentrations in breast milk.

A short review on human exposure to and tissue distribution of per- and polyfluoroalkyl substances (PFASs)

PFASs are widely distributed in natural and living environment and can enter human bodies via different routes. Many studies have reported that PFASs may be associated with human diseases, such as urine acid and thyroid diseases. In this study, we reviewed PFAS levels in human bodies reported in past seven years, including blood, urine, milk, and tissues (hair and nails). Most studies focused on human blood. Blood type, spatiality, human age, and gender were found to have a strong relationship with PFAS levels in blood samples. The PFAS distribution in urine samples was reported to be associated with the chain length of PFASs and human gender. Urinary excretion was found to be an important pathway of PFAS elimination. PFAS levels in human milk might be affected by various factors, such as mothers' age, dietary habit, parity of mothers and the interval of interpregnancy. Data in hair and nails remain very limited, but these matrices offer a non-invasive approach to evaluate human exposure to PFASs.

Occurrence of perfluoroalkyl substances in matched human serum, urine, hair and nail

The purpose of this study was to determine perfluoroalkyl substances (PFASs) in human serum, urine, hair and nail from general populations, and to investigate the possibility for human urine, hair and nail used as the biomonitoring sample for PFASs exposure. We detected the concentrations of PFHxA, PFOA, PFNA, PFDA, PFUnDA, PFDoA, PFHxS and PFOS in 39 matched human serum, urine, hair and nail samples from Shenzhen in China. The detection frequency and the median level of PFOS were all higher than that of the other PFASs in four matrices. The median concentration of PFOS in serum, urine, hair, and nail were 9.24ng/mL, 13.96ng/L, 0.58ng/g and 0.63ng/g, respectively. The results of spearman correlation test indicated that nail was an ideal matrix for biomonitoring PFOS rather than human urine and hair in general populations for the non-invasive sampling.

Perfluoroalkyl substances (PFASs) in breast milk from Korea: Time-course trends, influencing factors, and infant exposure

Breastfeeding is an important exposure pathway to perfluoroalkyl substances (PFASs) for newborn infants. Nevertheless, reports are limited on the occurrence and time-course of PFASs in breast milk, and most studies have focused on the analysis of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA). In this study, 16 PFASs were analyzed in breast milk samples (n=293) collected from 128 mothers in Korea during various lactation periods to assess maternal exposure levels, contamination profiles, time-course variations, and infant health risks. The total concentrations of PFASs (ΣPFAS) ranged from 31.7 to 1004 (median: 188) ng/L, which was within the ranges recently reported for Asian and European populations. After a month of nursing, the concentrations of PFOS, PFOA, perfluorononanoic acid (PFNA), and ΣPFAS significantly increased. This could be due to changes in the dietary and behavior patterns of the mothers after the first month of lactation. The concentrations of PFOS and PFOA were significantly correlated with maternal age, body mass index, and parity. Certain types of diet (e.g. consuming snacks and milk) and eating-out frequency were significantly associated with increasing levels of PFAS. Significant correlations and similar time-course trends were found between PFASs and PCBs/DDTs, implying similar exposure sources and biokinetics for these contaminants. The estimated daily intakes of PFOS and PFOA via the consumption of breast milk were below the tolerable daily intakes for infants suggested by the European Food Safety Authority (EFSA).

Molecular mechanisms of PFOA-induced toxicity in animals and humans: Implications for health risks

As an emerging persistent organic pollutant (POP), perfluorooctanoate (PFOA) is one of the most abundant perfluorinated compounds (PFCs) in the environment. This review summarized the molecular mechanisms and signaling pathways of PFOA-induced toxicity in animals and humans as well as their implications for health risks in humans. Traditional PFOA-induced signal pathways such as peroxisome proliferating receptor alpha (PPARα), constitutive androstane receptor (CAR), farnesoid X receptor (FXR), and pregnane-X receptor (PXR) may not be important for PFOA-induced health effects on humans. Instead, pathways including p53/mitochondrial pathway, nuclear lipid hyperaccumulation, phosphatidylinositol 3-kinase-serine/threonine protein kinase (PI3K-AKT), and tumor necrosis factor-α/nuclear factor κB (TNF-α/NF-κB) may play an important role for PFOA-induced health risks in humans. Both in vivo and in vitro studies are needed to better understand the PFOA-induced toxicity mechanisms as well as the associated health risk in humans.

Analysis of perfluorinated compounds in human serum from the general population in Shanghai by liquid chromatography-tandem mass spectrometry (LC-MS/MS)

Perfluorinated compounds (PFCs) have potential health risk to human. In this paper, human serum samples collected from Jiading District, Shanghai aged from 23 to 87 years old (12 male and 33 female) were analyzed for 17 perfluorinated compounds (PFCs). A novel method for the elimination of background contamination of perfluorooctanoic acid (PFOA) generated from instrument by the modification of high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) has also been developed and validated. The limit of detection (LOD) for all monitored PFCs range from 0.02 to 0.18 ng mL^-1. The limit of quantitation (LOQ) for PFOS and PFOA was 2.23 and 1.60 ng mL^-1, respectively, and for other PFCs it ranged from 0.04 to 0.88 ng mL^-1. Of the 17 PFCs analyzed in Shanghai serum, eleven were found. The dominating PFCs in all samples were perfluorooctanesulfonate (PFOS) and PFOA with a fraction of 49.5%, 34.2%, respectively. The median total concentration of each serum samples was 53.43 ng mL^-1 with a range from <LOD to 99.37 ng mL^-1. The results indicate a high human exposure to PFCs in Shanghai region. Compared with other cities in China and some other countries, PFOA and PFDA concentrations in the serum of general population of Shanghai are highest. For all donors, no significant association between age and PFCs was found (p = 0.125-0.951) and no workplace significant correlation was found (p = 0.247-0.861). Since no signification is founded and PFCs exposure is prevalent, further investigation is needed to explore its source and potential health impact. These results will also provide significant background data of PFCs in Shanghai.

Occurrence investigation of perfluorinated compounds in surface water from East Lake (Wuhan, China) upon rapid and selective magnetic solid-phase extraction

Using a novel magnetic nanocomposite as adsorbent, a convenient and effective magnetic solid-phase extraction (MSPE) procedure was established for selective separation and concentration of nine perfluorinated compounds (PFCs) in surface water sample. Then an ultra high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) system was employed for detection of PFCs. Good linearity of the developed analytical method was in the range of 0.5-100 ng L^-1 with R² > 0.9917, and the limits of detection (LODs) ranged from 0.029 to 0.099 ng L^-1. At three fortified concentrations of 0.5, 5 and 50 ng L^-1, the spiked recoveries of PFCs were in the range of 90.05-106.67% with RSDs < 12.62% (n = 3). The proposed analytical method was applied for determination of PFCs in surface water from East Lake (Wuhan, China). The total concentrations of nine PFCs ranged from 30.12 to 125.35 ng L^-1, with perfluorooctane sulfonate and perfluoroctanoic acid as the most prevalent PFCs, and the greatest concentrations of PFCs were observed in Niuchao lakelet. The concentrations of the PFCs (C ≥ 11) were mostly less than the limits of quantification (LOQs), attributed to the possibility that the more hydrophobic long-chain PFCs are potential to accumulate in sediment and aquatic biota.

Perfluoroalkyl and polyfluoroalkyl substances in cord blood of newborns in Shanghai, China: Implications for risk assessment

Perfluoroalkyl and polyfluoroalkyl substances (PFASs) are commonly used in industrial applications and consumer products, and their potential health impacts are of concern, especially for vulnerable population like fetuses. However, in utero exposure to PFASs and health implications are far from fully characterized in China. To fill in the gap, we analyzed 10 PFASs in cord plasma samples (N=687) collected in Shanghai between 2011 and 2012, one of the regions widely polluted with PFASs in China. A questionnaire survey on maternal and diet-related factors was conducted. Except for perfluoroheptanoic acid (PFHpA) and perfluorooctane sulfonamide (PFOSA), all other PFASs were detected in ˃90% of the samples. Perfluorooctanoic acid (PFOA) was the most predominant PFAS (median value: 6.96ng/mL), followed by perfluorooctane sulfonate (PFOS) (2.48ng/mL). PFOA and PFOS combined contributed to 80% of the total PFASs. The final multiple regression models showed that maternal factors including maternal age, body mass index, gestational age, economic status and educational level as well as consumption of fish and wheat were significantly related with concentrations of PFASs in cord blood. The risk assessment using the hazard quotients (HQs) approach on the basis of plasma PFAS levels indicated no potential concern for developmental toxicity in the local newborns. The results demonstrate the unique profiles of local prenatal exposure to PFASs, suggesting that PFOA has been the primary human exposure due to its widespread use and pollution. Special attention to high PFOA exposure and confirmation of potential determinants should be taken as a priority in the future plan for risk management and actions in this area.

Elevated levels of short carbon-chain PFCAs in breast milk among Korean women: Current status and potential challenges

Breast milks can be contaminated with perfluoroalkyl substances (PFASs). Exposure to PFASs during early stages of life may lead to adverse health effects among breastfed infants. To date, perfluorootanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) have been most frequently measured PFASs in breast milks worldwide. Information on shorter carbon-chain PFASs in breast milk is scarce. In this study, breast milks were sampled from 264 Korean lactating women, and measured for seventeen PFASs, including ten perfluoroalkyl carboxylates (PFCAs), four perfluoroalkyl sulfonates, and three perfluoroalkyl sulfonamides. PFOA and PFOS were detected in 98.5% of the breast milk samples, with median concentrations of 0.072 and 0.050ng/mL, respectively. Perfluoropentanoic acid (PFPeA), perfluorohexanoic acid (PFHxA), and perfluoroheptanoic acid (PFHpA) were detected in higher frequencies, ranging between 67.4% and 81.8%. The concentrations of short carbon-chain PFCAs in breast milk such as PFPeA and PFHxA were the highest ever reported to date, and were comparable to that of PFOS. Concentrations of shorter chain PFCA in breast milk tended to be higher among the women with longer lactation period, while those of PFOA showed the opposite trend, suggesting a possibility that breastfeeding might be an important route of excretion for PFOA among lactating women. Fish consumption and the use of consumer products, e.g., skin care products, cosmetics and non-stick coated cooking utensils, were identified as significant predictors of PFAS concentrations in breast milk. Health risks associated with PFOA and PFOS exposure through breastfeeding were estimated negligible, however, risks of the short carbon-chain PFCAs could not be assessed because of lack of relevant toxicological information. Further efforts for source identification and exposure management measures for shorter chain PFCAs are necessary.

Perfluorinated carboxylic acids in human breast milk from Spain and estimation of infant's daily intake

Human milk samples were collected from 67 mothers in 2014 at a Primary Care Centre in Murcia (Spain) and analyzed for perfluorinated carboxylic acids (PFCAs). Concentrations measured for perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnDA) and perfluorododecanoic acid (PFDoDA) ranged from <LOQ (<10 ng/L) to 397 ng/L with a mean concentration of 66 ± 68 ng/L and a median of 29 ng/L. The presence of these compounds was revealed in 50 samples out of 67 analyzed. Influence of number of pregnancies and food habits on PFCAs concentrations was also investigated. Statistically significant differences in PFCA levels were found when the women were divided into maternal age classes and into the categories primiparae and multiparae. A greater transfer of PFC during breastfeeding by primiparous was evidenced and thus a higher exposure to these contaminants for the first child. Moreover, it was possible to hypothesize that the content of PFCs is in general correlated to the eating habits of donors and, in particular, with the fish consumption. Finally, PFOA daily intakes and risk index (RI) were estimated for the first six months of life and we found that ingestion rates of PFOA did not exceed the tolerable daily intake (TDI) recommended by the European Food Safety Authority (EFSA).

Perfluoroalkyl acid (PFAA) levels and profiles in breast milk, maternal and cord serum of French women and their newborns

One major concern regarding perfluoroalkyl acids (PFAAs) is their potential role in onset of health troubles consecutive to early exposure during the perinatal period. In the present work, the internal exposure levels of 18 targeted PFAAs were determined in ca. 100 mother-newborn pairs recruited in France between 2010 and 2013. In serum, the cumulated concentrations of the 7 most frequently detected compounds were 5.70ng/mL and 2.83ng/mL (median values) in maternal and cord serum, respectively. Perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexylesulfonic acid (PFHxS) and perfluorononanoic acid (PFNA) contributed to around 90% of the total PFAAs contamination, with concentration levels and contamination profiles in accordance with other published work in Europe. Levels measured in breast milk were far lower (20 to 150 fold) than those determined in serum. Associations between the different monitored substances as well as between levels determined in the different investigated biological matrices mostly do not appear statistically significant. The estimated materno-foetal transfer would be thus substance-dependant, mainly driven by the physico-chemical properties of the different PFAAs (nature of polar group and length of alkylated side chain). We conclude that trans-placental passage and breastfeeding are both significant routes of human exposure to PFAAs.

Perfluoroalkyl and polyfluoroalkyl substances in consumer products

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are used in a wide range of products of all day life. Due to their toxicological potential, an emerging focus is directed towards their exposure to humans. This study investigated the PFAS load of consumer products in a broad perspective. Perfluoroalkyl sulfonic acids (C4, C6-C8, C10-PFSA), carboxylic acids (C4-C14-PFCA) and fluorotelomer alcohols (4:2, 6:2; 8:2 and 10:2 FTOH) were analysed in 115 random samples of consumer products including textiles (outdoor materials), carpets, cleaning and impregnating agents, leather samples, baking and sandwich papers, paper baking forms and ski waxes. PFCA and PFSA were analysed by HPLC-MS/MS, whereas FTOH were detected by GC/CI-MS. Consumer products such as cleaning agents or some baking and sandwich papers show low or negligible PFSA and PFCA contents. On the other hand, high PFAS levels were identified in ski waxes (up to about 2000 μg/kg PFOA), leather samples (up to about 200 μg/kg PFBA and 120 μg/kg PFBS), outdoor textiles (up to 19 μg/m(2) PFOA) and some other baking papers (up to 15 μg/m(2) PFOA). Moreover, some test samples like carpet and leather samples and outdoor materials exceeded the EU regulatory threshold value for PFOS (1 μg/m(2)). A diverse mixture of PFASs can be found in consumer products for all fields of daily use in varying concentrations. This study proves the importance of screening and monitoring of consumer products for PFAS loads and the necessity for an action to regulate the use of PFASs, especially PFOA, in consumer products.