Comparison of per- and polyfluoroalkyl substance exposure levels in neonatal cord blood between an e-waste recycling area and a general exposure area

Abstract

BackgroundPer- and polyfluoroalkyl substances (PFAS) are a class of persistent organic pollu-tants. Industrial production and consumer use of PFAS are the primary sources of exposure in urban areas. E-waste recycling activities are also a significant source of environmental PFAS exposure. ObjectiveTo compare exposure profiles between traditional and emerging PFAS in neonatal cord blood collected from an e-waste recycling area and a general exposure area characterized by modern economic development (hereafter referred to as general exposure area). MethodsBased on a birth cohort study conducted in 2018, 85 pregnant women were recruited (36 participants from an e-waste recycling area and 49 participants from a general exposure area). Neonatal cord blood was collected at delivery. Ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was used to detect 28 common PFAS in the blood. A structured questionnaire was used to gather sociodemographic characteristics of the pregnant women. Mann-Whitney U tests were used to compare PFAS exposure levels in neonatal cord blood between the e-waste recycling area and the general exposure area. Multiple linear regression models were used to explore the influence of residing in the e-waste recycling area on neonatal PFAS exposure, with area as the independent variable and the natural logarithm of PFAS exposure levels as the dependent variable. ResultsA total of 22 PFAS were positive in neonatal cord blood, of which 13 congeners were 100% detectable in the samples from both areas. The median ∑PFAS exposure levels in neonatal cord blood were 14.19 ng·mL−1 and 14.02 ng·mL−1 for the e-waste recycling area and the general exposure area, respectively, with linear perfluorooctanoic acid (L-PFOA) showing the highest median concentration (5.49 ng·mL−1 and 6.39 ng·mL−1, respectively). The results of Mann-Whitney U tests showed that the median exposure levels of long-chain perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnDA), perfluorododecanoic acid (PFDoDA), and perfluorotridecanoic acid (PFTrDA), as well as emerging alternatives 6:2 chlorinated polyfluorinated ether sulfonate (6:2 Cl-PFESA) and 8:2 chlorinated polyfluorinated ether sulfonate (8:2 Cl-PFESA), were higher in the e-waste recycling area than in the general exposure area. In contrast, the median exposure levels of short-chain perfluoropentanoic acid (PFPeA) and perfluorohexanoic acid (PFHxA), as well as perfluorooctanoic acid (PFOA) branched isomers, including perfluoro-6-methylheptanoic acid (iso-PFOA), perfluoro-5-methylheptanoic acid (5m-PFOA), and perfluoro-4-methylheptanoic acid (4m-PFOA), were lower in the e-waste recycling area than in the general exposure area (P<0.05). The multiple linear regression models showed that, compared to the general exposure area, neonatal cord blood in the e-waste recycling area had significantly higher exposure levels of long-chain PFDA, PFUnDA, PFDoDA, PFTrDA, and emerging alternatives 6:2 Cl-PFESA and 8:2 Cl-PFESA, with odds ratios of 1.95 (95%CI: 1.39-2.75), 2.10 (95%CI: 1.58-2.75), 2.12 (95%CI: 1.39-3.25), 2.64 (95%CI: 1.63-4.22), 3.46 (95%CI: 2.34-5.10), and 3.25 (95%CI: 2.01-5.26), respectively. Conversely, the exposure levels of short-chain PFPeA, PFHxA, and branched PFOA (br-PFOA) were significantly lower, with odds ratios of 0.44 (95%CI: 0.38-0.52), 0.30 (95%CI: 0.16-0.57), and 0.50 (95%CI: 0.38-0.67), respectively. ConclusionPFAS are widely present in neonatal cord blood in both the e-waste recycling area and the general exposure area. Compared to the general exposure area, the neonatal cord blood samples in the e-waste recycling area show higher exposure levels of certain long-chain perfluoroalkyl carboxylic acids (PFCA) and emerging PFAS alternatives, while the neonatal cord blood samples in the general exposure area show higher exposure levels of some short-chain PFCA and PFOA branched isomers.

Keywords

• per-and polyfluoroalkyl substances
• cord blood
• e-waste recycling area
• exposure level