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Perfluoroalkyl substances (PFASs) are persistent organic pollutants, which are widely used in consumer and industrial products and can cause direct or indirect toxic effects on multiple organs (1-2). Due to the increasingly stringent controls on the production and use of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonate (PFOS), plenty of alternatives are used. However, recent studies indicated that some alternatives may be more bio-accumulative or toxic than those legacy PFASs (3-4). In order to investigate the latest dietary exposure of legacy and emerging contaminants for Chinese adults, composite food samples were collected from 24 provincial-level administrative divisions (PLADs) in the Sixth China Total Diet Study (TDS) during 2016–2019. The mean EWIs of PFOS, PFOA, and 9-chlorohexadecafluoro-3-oxanonane-1-sulfonate (6:2 Cl-PFESA) in the Sixth TDS were 2.72, 2.17, and 2.75 ng/kg body weight per week, respectively, indicating low health risks via dietary exposure of these PFASs for most of the population in China. The related results could provide basic data for the health effect assessment of PFASs and also provide a scientific basis for control measures of health damage caused by PFASs.
In this study, 25 legacy PFASs including typical isomers [perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA), perfluoro-n-octanoic acid (n-PFOA), perfluoro-4-methylheptanoic acid (4m-PFOA), perfluoro-5-methylheptanoic acid (5m-PFOA), perfluoro-6-methylheptanoic acid (iso-PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUdA), perfluorododecanoic acid (PFDoA), perfluorotridecanoic acid (PFTrDA), perfluorotetradecanoic acid (PFTeDA), perfluorobutanesulfonate (PFBS), perfluoropentanesulfonate (PFPeS), perfluorohexanesulfonate (PFHxS), perfluoroheptanesulfonate (PFHpS), perfluoro-1-octanesulfonate (n-PFOS), perfluoro-1-methylheptanesulfonate (1m-PFOS), perfluoro-3-methylheptanesulfonate (3m-PFOS), perfluoro-4-methylheptanesulfonate (4m-PFOS), perfluoro-5-methylheptanesulfonate (5m-PFOS), and perfluoro-6-methylheptanesulfonate (iso-PFOS), perfluorononanesulfonate (PFNS), perfluorodecanesulfonate (PFDS), and perfluorododecanesulfonate (PFDoS)] and 3 emerging PFASs [6:2 Cl-PFESA, 11-chloroeicosafluoro-3-oxaundecane-1-sulfonate (8:2 Cl-PFESA), and dodecafluoro-3H-4,8-dioxanonanoate (ADONA)] were analyzed in the food samples. The details of the TDS are described in the Foreword of this issue (5). The sample preparation and instrumental analysis
was described in detail in our previous studies (6-7). The concentrations below the limits of detection (LOD) were set to be LOD/2. In the present study, PFHxA, PFHpS, PFNS, PFDS, PFDoS, 8:2 Cl-PFESA, and ADONA were not found in all food samples (n=216). The summary of detection frequency (DF) and concentration of detectable PFASs and alternatives in all food samples are shown in Supplementary Table S1. The most commonly detected PFASs in all samples were PFOS, PFOA, PFUdA, PFDA, PFNA and 6:2 Cl-PFESA, the last of which was one of the contaminants of high concern in recent years. Generally, the DFs of perfluoroalkyl carboxylates (PFCAs) were higher than that of the PFSAs. Except for milk samples, the DF of PFASs in animal-origin food samples was much higher than that in vegetal-origin food samples. None of PFASs and their alternatives were detected in the milk samples. Most of the PFASs were detected in aquatic food, especially for long chain PFCAs, PFOS, and its predominant alternative (6:2 Cl-PFESA) with 100% DF. Similar to the DF, the levels of PFASs in foods of animal-origin were much higher than those vegetal-origin food samples. The estimated weekly intakes (EWIs) of PFOS, PFOA, and 6:2 Cl-PFESA in 24 PLADs were shown in Table 1 and Figure 1. The mean EWIs of PFOS and PFOA in the Sixth TDS accounted for 20.9% and 36.2% of the tolerable weekly intake (TWI) set by EFSA in 2018 (13 ng/kg body weight per week for PFOS and 6 ng/kg body weight per week for PFOA) (8). The average TWI of 6:2 Cl-PFESA was very close to PFOS.
PLADs PFOA PFOS 6:2 Cl-PFESA Heilongjiang 0.77 14.28 1.03 Liaoning 0.67 1.46 0.30 Hebei 0.61 0.96 0.10 Beijing 13.73 1.59 0.15 Jilin 0.70 1.88 0.34 Shanxi 0.70 1.62 0.30 Shaanxi 8.54 0.88 0.05 Henan 0.27 0.76 0.20 Ningxia 2.61 0.43 0.02 Inner Mongolia 0.89 1.04 0.27 Qinghai 0.32 0.41 0.03 Gansu 0.61 0.57 0.05 Shanghai 3.52 5.23 3.94 Fujian 1.90 2.32 0.55 Jiangxi 2.73 4.15 0.44 Jiangsu 2.07 2.65 1.91 Zhejiang 3.74 8.67 51.57 Shandong 5.32 2.31 0.38 Hubei 0.63 2.43 0.54 Sichuan 0.58 1.63 0.59 Guangxi 0.28 1.17 0.13 Hunan 0.33 5.37 2.63 Guangdong 0.18 2.84 0.47 Guizhou 0.42 0.55 0.04 Average 2.17 2.72 2.75 Abbreviations: PFOS=perfluorooctanesulfonate; PFOA= perfluorooctanoic acid; 6:2 Cl-PFESA=9-chlorohexadecafluoro-3-oxanonane-1-sulfonate; PLADs=provincial-level administrative divisions. Table 1. The EWIs (ng/kg body weight per week) of PFOA, PFOS, and 6:2 Cl-PFESA in 24 PLADs in China, 2016–2019.
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No conflicts of interest.
Food category PFHpA PFOA* PFNA PFDA PFUdA PFDoA PFTrDA PFTeDA PFBS PFPeS PFHxS PFOS* 6:2 Cl-PFESA 8:2 Cl-PFESA Meats DF (%) 12.5 75.0 41.7 33.3 41.7 8.3 16.7 0.0 4.2 0.0 4.2 79.2 41.7 4.2 Range <0.002 to
0.09<0.006 to
0.15<0.002 to
0.03<0.002 to
0.04<0.002 to
0.05<0.003 to
0.01<0.003 to
0.03−† <0.003−
0.12−† <0.003 to
0.05<0.004 to
0.53<0.004 to
3.73<0.004 to
0.07Means 0.01 0.04 0.01 0.01 0.01 <0.003 0.01 −† 0.01 −† 0.004 0.06 0.17 0.005 Median <0.002 0.029 <0.002 <0.002 <0.002 <0.003 <0.003 −† <0.003 −† <0.003 0.021 <0.004 <0.004 Eggs DF (%) 0.0 83.3 29.2 54.2 45.8 4.2 12.5 12.5 0.0 8.3 8.3 95.8 29.2 0.0 Range −† <0.001 to
2.97<0.001 to
0.02<0.001 to
0.07<0.001 to
0.02<0.001 to
0.01<0.001 to
0.02<0.001 to
0.01−† <0.002 to
0.01<0.001 to
0.02<0.002 to
0.19<0.001 to
0.04−† Means −† 0.18 0.004 0.01 0.01 <0.001 0.002 0.002 −† <0.002 0.002 0.07 0.01 −† Median −† 0.020 <0.001 0.01 <0.001 <0.001 <0.001 <0.001 −† <0.002 <0.001 0.06 <0.001 −† Aquat−† DF (%) 4.2 66.7 91.7 100.0 100.0 100.0 100.0 75.0 8.3 4.2 0.0 100.0 100.0 25.0 Range <0.001 to
0.03<0.002 to
0.26<0.001 to
0.290.022 to
0.520.033 to
0.320.009 to
0.150.022 to
0.27<0.003 to
0.07<0.002 to
0.02<0.002 to
0.01−† 0.059 to
4.300.008 to
0.49<0.002 to
0.15Means 0.002 0.05 0.06 0.09 0.15 0.04 0.11 0.02 <0.002 <0.002 −† 0.48 0.14 0.01 Median <0.001 0.02 0.05 0.06 0.12 0.04 0.08 0.02 <0.002 <0.002 −† 0.29 0.10 <0.002 Cereals DF (%) 4.2 12.5 0.0 4.2 0.0 0.0 0.0 0.0 12.5 4.2 8.3 4.2 0.0 0.0 Range <0.001 to
0.03<0.001 to
0.09−† <0.005 to
0.01−† −† −† −† <0.001 to
0.04<0.005 to
0.11<0.005 to
0.16<0.001 to
0.01−† −† Means 0.002 0.01 −† <0.005 −† −† −† −† 0.004 0.01 0.01 <0.001 −† −† Median <0.001 <0.001 −† <0.005 −† −† −† −† <0.001 <0.005 <0.005 <0.001 −† −† Legumes DF (%) 4.2 12.5 0.0 4.2 0.0 4.2 0.0 4.2 16.7 8.3 12.5 4.2 0.0 0.0 Range <0.015 to
0.21<0.005 to
0.06−† <0.004 to
0.01−† <0.015 to
0.02−† <0.015 to
0.03<0.010 to
0.23<0.010 to
0.06<0.010 to
0.11<0.005 to
0.08−† −† Means 0.02 0.01 −† <0.004 −† <0.015 −† <0.015 0.02 <0.010 0.01 <0.010 −† −† Median <0.015 <0.005 −† <0.004 −† <0.015 −† <0.015 <0.010 <0.010 <0.010 <0.010 −† −† Potatoes DF (%) 0.0 16.7 0.0 12.5 4.2 8.3 0.0 0.0 16.7 12.5 4.2 0.0 0.0 0.0 Range −† <0.001
to
0.05
−†
<0.002 to
0.02<0.002 to
0.02<0.004
to
0.02−† −† <0.002 to
0.03<0.002 to
0.02<0.002
to
0.02−† −† −† Means −† 0.004 −† 0.003 <0.002 <0.004 −† −† 0.01 0.003 <0.002 −† −† −† Median −† <0.001 −† <0.002 <0.002 <0.004 −† −† <0.001 <0.002 <0.002 −† −† −† Vegetables DF (%) 0.0 20.8 0.0 8.3 8.3 8.3 0.0 0.0 0.0 37.5 4.2 0.0 0.0 0.0 Range −† <0.006 to
0.04−† <0.006 to
0.02<0.004 to
0.01<0.005 to
0.03−† −† −† <0.010 to
0.05<0.006 to
0.03−† −† −† Means −† 0.01 −† <0.006 <0.004 <0.005 −† −† −† 0.02 <0.006 −† −† −† Median −† <0.006 −† <0.006 <0.004 <0.005 −† −† −† <0.010 <0.006 −† −† −† Fruits DF (%) 0.0 0.0 0.0 0.0 0.0 8.3 0.0 0.0 0.0 0.0 0.0 4.2 0.0 0.0 Range −† −† −† −† −† <0.002 to
0.02−† −† −† −† −† <0.002 to
0.01−† −† Means −† −† −† −† −† <0.002 −† −† −† −† −† <0.002 −† −† Median −† −† −† −† −† <0.002 −† −† −† −† −† <0.002 −† −† Abbreviations: PFHpA=perfluoroheptanoic acid; PFOA=perfluorooctanoic acid; PFNA=perfluorononanoic acid; PFDA=perfluorodecanoic acid; PFUdA=perfluoroundecanoic acid; PFDoA=perfluorododecanoic acid; PFTrDA=perfluorotridecanoic acid; PFTeDA=perfluorotetradecanoic acid; PFBS=perfluorobutanesulfonate; PFPeS=perfluoropentanesulfonate; PFHxS=perfluorohexanesulfonate; PFOS=perfluorooctanesulfonate; 6:2 Cl-PFESA= 9-chlorohexadecafluoro-3-oxanonane-1-sulfonate; 8:2 Cl-PFESA=11-chloroeicosafluoro-3-oxaundecane-1-sulfonate; PLADs=provincial-level administrative division.
* the concentration of PFOA/PFOS included linear PFOA/PFOS and br-PFOA/PFOS.
† no data.Table S1. The mean and median concentrations (ng/g wet weight) and DF of other PFASs in all food samples
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