Prenatal exposure and transplacental transfer of perfluoroalkyl substance isomers in participants from the upper and lower reaches of the Yangtze River

Data on gestational exposure characteristics and transplacental transfer are quite limited for perfluoroalkyl substance (PFAS) isomers, especially those from large-scale comparative studies. To fill this gap, we examined isomers of perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), and perfluorohexane sulfonic acid (PFHxS) in matched maternal and cord serum from Mianyang and Hangzhou, which are located in the upper and lower reaches of the Yangtze River, China, respectively. These data were compared with those from our previous study on Wuhan in the middle reach. The average ΣPFAS concentration increased from upstream to downstream (Mianyang (4.44 ng/mL) < Wuhan (9.88 ng/mL) < Hangzhou (19.72 ng/mL)) and may be related to the per capita consumption expenditure of each city. The ln-transformed PFAS concentrations showed significant differences between Mianyang and Hangzhou after adjusting confounding factors (p < 0.05). The percentages of linear PFOS and PFOA in maternal and cord serum from these cities all exceeded those in electrochemical fluorination products. The isomer profiles of PFASs in maternal and cord serum might be greatly influenced by local production processes of PFASs and residents’ dietary habits. The transplacental transfer efficiencies decreased significantly with increasing concentrations in maternal serum for ΣPFAS, ΣPFOS, ΣPFOA, ΣPFHxS, n-PFOS, iso-PFOS, 4m-PFOS, 1m-PFOS, n-PFOA, n-PFHxS, and br-PFHxS (Spearman rank correlation coefficients (r) = 0.373–0.687, p < 0.01). These findings support an understanding of the regional characteristics in maternal exposure to PFASs along the Yangtze River, isomeric profiles of PFASs in these regions, and the transplacental transfer processes of PFAS isomers

Mass spectrometry-based multimodal approaches for the identification and quantification analysis of microplastics in food matrix

BackgroundMicroplastics (MPs) and nanoplastics (NPs) have become emerging contaminants worldwide in food matrices. However, analytical approaches for their determination have yet to be standardized. Therefore, a systematic study is urgently needed to highlight the merits of mass spectrometry (MS) based methods for these applications.PurposeThe aim of the study is to review the current status of MS-based multimodal analysis for the determination of MPs in food matrices.MethodsWeb of Science and Google Scholar databases were searched and screened until Jan. 2023. Inclusion criteria: “publication years” was set to the last decades, “English” was selected as the “language,” and “research area” was set to environmental chemistry, food analysis and polymer science. The keywords were “microplastics,” “nanoplastics,” “determination,” “identification/quantification,” and “mass spectrometry.”ResultsTraditional spectrometry techniques offer good abilities to conduct the multimodal analysis of MPs in terms of color, shape and other morphologies. However, such technologies have some limitations, in particular the relatively high limits of detection. In contrast, MS-based methods supply excellent supplements. In MS-based methods, gas chromatographic-mass spectrometry (GC-MS), and LC-MS/MS were selected as representative methods for determining MPs in the food matrices, while specialized MS methods (i.e., MALDI-ToF MS and ToF-SIMS) were considered to offer great potential in multimodal analysis of MPs especially when interfaced with the imaging systems.SignificanceThis study will contribute to gaining a deeper insight into the assessment of the exposure levels of MPs in human body, and may help build a bridge between the monitoring studies and the toxicology field

Microplastics in Widely Used Polypropylene-Made Food Containers

As a potential threat to human health, ingestion of microplastics (MPs) has become of concern. Limited studies have carefully characterized the occurrence of MPs in polypropylene-made takeout food containers (TOFCs), which have been widely used in China. In this study, TOFC samples (n = 210) were collected from seven Chinese cities (Hangzhou, Guangzhou, Shanghai, Xining, Chengdu, Qingdao, and Dalian) and analyzed for MPs. All the TOFC samples contained MPs, with an abundance of 3&ndash;43 items/TOFC. The TOFCs from Chengdu (25 items/TOFC) contained the highest mean abundance of MPs, which is significantly (p &lt; 0.01) higher than that from Shanghai (8.7 items/TOFC). Fiber accounted for 66&ndash;87% of the total for the shape of the MPs in the TOFCs from the different Chinese cities. Most of the MPs in the TOFCs from the different cities had a size of 201&ndash;500 &mu;m and accounted for a mean 34&ndash;42% of the total MPs in the TOFCs. The major color type of the MPs in the TOFCs was transparent, accounting for a mean 39 (Qingdao)&ndash;73% (Hangzhou) of the total MPs. Polymer compositions of the MPs in the TOFCs were consistently dominated by polypropylene, which represented a mean 56&ndash;73% of the total MPs. The estimated daily intake of MPs for the general Chinese population through using TOFCs was in the range of 0.042&ndash;0.14 items/kg bw/day. To our knowledge, this is the most comprehensive study investigating the occurrence of MPs in TOFCs from China, which contributes to a better understanding of the sources of human oral exposure to MPs

Isomer Profiles of Perfluoroalkyl Substances in Water and Soil Surrounding a Chinese Fluorochemical Manufacturing Park

Despite that China is the largest global manufacturer of perfluoroalkyl substances (PFASs), the manufacturing methods and isomer purity of these chemicals are generally unknown. Here, sampling was conducted around a major fluorochemical manufacturing park in China in 2012, including soil and water collection inside the park, including from a wastewater treatment plant (WWTP), as well as in surrounding rivers and soil (∼15 km radius). Perfluoroalkyl sulfonates (PFSAs) were lower than perfluoroalkyl carboxylates (PFCAs) in all samples, and short-chain (C₄–C₆) PFCAs were predominant. Perfluoroalkyl phosphonates and phosphate diesters were occasionally detected, but at low detection frequency. Branched isomers of perfluorobutanesulfonate (PFBS) are reported for the first time, accounting for 15–27% of total PFBS in water. An enrichment of isopropyl-PFOA (28%) was found in WWTP influent, suggesting its manufacturing primarily by isopropyl telomerization. More numerous branched isomers were observed for the longer C₉–C₁₃ PFCAs (e.g., C₁₂ PFCA had 16 branched isomers), including high proportions of one major branched isomer (likely isopropyl), possibly as impurities from isopropyl-PFOA manufacturing. Overall, short-chain perfluorinated acids were the predominant PFASs being released, but PFOA was still a major chemical in use at this site, primarily from isopropyl telomerization

Occurrence and Partitioning of Bisphenol Analogues in Adults’ Blood from China

Widespread human exposure and associated adverse health effects led to regulations on the usage of bisphenol A (BPA). Several bisphenol analogues (BPs) have been introduced as BPA alternatives in various applications. However, these BPs have been shown to exhibit similar or even stronger endocrine-disrupting activities compared with that of BPA. Currently, information on the human exposure to BPA alternatives remains limited. In this study, nine BPs were quantified in 81 pairs of plasma and red blood cell (RBC) samples from Chinese participants. In human plasma, the predominant BPs was BPA, bisphenol S (BPS), and bisphenol AF (BPAF), with the mean concentrations of 0.40, 0.15, and 0.073 ng/mL, respectively. BPA (accounting for 63% of total BPs) and BPS (18%) were the major BPs in the RBC fraction. Mass fractions in plasma (<i>F</i>_p) were found to be highest for BPS (mean, 0.78), followed by BPAF (0.71) and BPA (0.67), indicating strong partitioning to the plasma fraction. However, bisphenol AP was more frequently detected in the RBC fraction. Estimated total daily intake (EDI) of BPA was in the range of 0.0048–0.75 μg/kg bw/day for the participants, and adults aged >50 years had comparatively lower EDI. To our knowledge, this is the first study to assess the occurrence and partitioning of BPA alternatives in paired human plasma and RBCs from the Chinese general population

Perfluoroalkyl Acids Including Isomers in Tree Barks from a Chinese Fluorochemical Manufacturing Park: Implication for Airborne Transportation

Measurement of airborne perfluoroalkyl acids (PFAAs) is challenging, but important for understanding their atmospheric transport. Tree bark is good media for monitoring semivolatile compounds in the atmosphere. Whether it could work as an indicator of airborne PFAAs was first examined in this study. Bark and leaf samples collected around a Chinese fluorochemical manufacturing park (FMP) were analyzed for PFAAs and their branched isomers. Total PFAA concentrations (∑PFAAs) in the bark (mean, 279 ng/g dw) and leaf (250 ng/g dw) samples were comparable. ∑PFAAs in the barks collected within the boundaries of the FMP were significantly (<i>p</i> < 0.05) higher than those outside the FMP, and displayed a decreasing spatial trend as the distance from the FMP increased. However, such spatial difference and trend were not observed for the leaves. PFAA compositional profiles in most of the tree barks were consistent with each other, but different from those in tree leaves. These results indicated that tree barks mainly accumulated airborne PFAAs, while uptake from soil and translocation could make partial contribution to those in leaves. Perfluorooctanoate and perfluorooctanesulfonate in barks had strictly consistent isomeric compositions with their electrochemical fluorination products. Overall, these results indicated that the bark could be a good indicator of airborne PFAAs with respect to their occurrence, isomeric signature, and atmospheric transport

Isomer–Specific Distribution of Perfluoroalkyl Substances in Blood

Perfluoroalkyl substances (PFASs) such as perfluorohexanesulfonate (PFHxS), perfluorooctanoate (PFOA), perfluorooctanesulfonate (PFOS) and PFOS–precursors are routinely measured in human plasma and serum, but their relative abundance in the blood cell fraction has not been carefully examined, particularly at the isomer–specific level. Human plasma and whole blood were collected and partitioning behaviors of PFASs and their isomers between plasma and blood cells were investigated. In human samples, mass fraction in plasma (<i>F</i>_p) for PFASs increased among perfluoroalkyl carboxylates as the carbon chain length increased from C6 (mean 0.24) to C11 (0.87), indicating preference for the plasma fraction with increasing chain length. However, among perfluoroalkyl sulfonates, PFHxS (mean 0.87) had a slightly higher <i>F</i>_p than PFOS (0.85). In vitro assays with spiked Sprague–Dawley rat blood were also conducted, and the results showed that PFOS–precursors had lower <i>F</i>_p values than perfluoroalkyl acids, with perfluoroctanesulfonamide having the lowest <i>F</i>_p (mean 0.24). Consistently, linear isomers of PFOS and PFOS–precursors had lower mean <i>F</i>_p than their corresponding total branched isomers. Multiplying by a factor of 2 is not a reasonable method to convert from whole blood to plasma PFAS concentrations, and current ratios could be used as more accurate conversion factors

Airborne Trifluoroacetic Acid and Its Fraction from the Degradation of HFC-134a in Beijing, China

Trifluoroacetic acid (TFA) has been attracting increasing attention worldwide because of its increased environmental concentrations and high aquatic toxicity. Atmospheric deposition is the major source of aquatic TFA, but only a few studies have reported either air concentrations or deposition fluxes for TFA. This is the first study to report the atmospheric concentrations of TFA in China, where an annular denuder and filter pack collection system were deployed at a highly urbanized site in Beijing. In total, 144 air samples were collected over the course of 1 year (from May 2012 to April 2013) and analyzed directly using high-performance liquid chromatography–tandem mass spectrometry (HPLC-MS/MS) or following derivatization by gas chromatography–mass spectrometry (GC–MS). The annual mean atmospheric concentration of TFA was 1580 ± 558 pg/m³, higher than the previously reported annual mean levels in Germany and Canada. For the first time, it was demonstrated that maximum concentrations of TFA were frequently observed in the afternoon, following a diurnal cycle and suggesting that a major source of airborne TFA is likely degradation of volatile precursors. Using a deposition model, the annual TFA deposition flux was estimated to be 619 ± 264 μg m^–2 year^–1. Nevertheless, a box model estimated that the TFA deposition flux from the degradation of HFC-134a contributed only 14% (6–33%) to the total TFA deposition flux in Beijing. Source analysis is quite important for future TFA risk predictions; therefore, future research should focus on identifying additional sources