Exposure Assessment Of Per-and Polyfluoroalkyl Substances In Chinese Residents

Per-and polyfluoroalkyl substances(PFASs)are widely found in the environment and they are persistent and bioaccumulative,potentially posing a potential threat to human health,such as liver toxicity,immunotoxicity,reproductive toxicity,and endocrine disorders.Each PFAS exhibits different environmental behaviors,pharmacokinetics,and toxicity.Therefore,international production and use of PFOA and PFOS are limited.Some fluorides containing ether bonds are replacing PFOS and PFOA in production and life.The application and use of HFPO-DA and NaDONA are used to replace PFOA and F-53B(including 6:2 Cl-PFESA and 8:2 Cl-PFESA)is used to replace PFOS.Studies have shown that these alternatives have high affinity with proteins and cannot be metabolized in living organisms,which will have adverse effects on the human body.Therefore,it is necessary to carry out refined analysis of dietary and human exposure levels of per-and polyfluoroalkyl substances and conduct a more comprehensive risk assessment.This study obtained the pollution levels of traditional PFASs and their typical isomers in animal foods from 11 provinces(municipalities and autonomous regions)in China's sixth total dietary survey.The results showed that the concentrations of PFASs in aquatic diets in Liaoning,Jilin,Henan,Shanghai,Fujian,Jiangxi,Guangxi and Hunan provinces were higher than those in local meats and eggs.The highest concentration of PFASs in Beijing was eggs.The presence of 4m-PFOA,5m-PFOA,and iso-PFOA was found only in the egg diet of Beijing,and the concentration of n-PFOA was as high as 2801.84 pg/g.There was no detection of branched PFOA in animal diet samples in other regions.Branched PFOS was mainly obtained in aquatic diets,it was detected that 3m+4m-PFOS was found in meat diets in some areas,so the production methods and use levels of PFASs in different regions of China were different.By analyzing the daily dietary intake of PFASs,dietary intake of residents is related to dietary consumption and the level of contamination of PFASs in the diet.The dietary exposure of PFASs in residents of Beijing and Gansu Province mainly comes from n-PFOA in egg diet.The dietary exposure of residents in Liaoning Province,Jilin Province and Hunan Province is mainly derived from n-PFOS in meat diet.Henan,Shanghai.Fujian,and Jiangxi provinces are mainly derived from n-PFOS in aquatic diets.Among them,Beijing residents' daily intake of n-PFOA through animal diet was 1820.41 pg/kg b.w./day,which was 2 times higher than the tolerable weekly allowance(TWI)recommended by the European Food Safety Authority(EFSA),and mainly due to the intake of egg diet(1727.36 pg/kg b.w./day),so the intake of eggs by Beijing residents may pose certain risks to health.In other areas,adult PFASs that are consumed daily by animal diets do not pose a risk to their health.An on-line SPE method of 46 PFASs in serum containing per-and polyfluoroalkyl substances and alternatives was established by on-line solid phase extraction(SPE)-ultra-high performance liquid chromatography-quadrupole/orbitrap high resolution mass spectrometry.The established method was used to analyze the PFASs load levels of 480 pregnant women's serum samples in Tianjin.A nested case-control study was conducted for each case matching a control group to analyze the effect of the concentration of PFASs on glucose metabolism in pregnant women.Twelve perfluoroalkylcarboxylic acids(PFCAs),six perfluoroalkylsulfonates(PFSAs),ten precursors,and two alternatives(HFPO-DA and NaDONA)in pregnant women's serum were almost undetected.The highest average concentration of 6:2 Cl-PFESA(6.828 ng/mL)has exceeded the highest exposed n-PFOS(5.509 ng/mL)in traditional PFASs,followed by n-PFOA(2.834 ng/mL),PFPeS(1.462 ng/mL),the average concentration of other PFASs with a detection rate exceeding 50%is less than 1 ng/mL(0.181-0.903 ng/mL).By Pearson correlation coefficient analysis,6:2 Cl-PFESA,8:2 Cl-PFESA,and PFOS isomers have the same source,indicating that F-53B is replacing PFOS in industrial production in Tianjin.In addition,the exposure of HFPO-DA and NaDONA may not exist in the environment of Tianjin or the bioaccumulative ability of these two alternatives in the human body is weak,which needs further proof by experiments.Since the PFOS precursor was almost undetected in this study,the high exposure of PFOS in this sample was not related to the exposure of the precursor material.From the composition of PFOS isomers in pregnant women's serum in Tianjin,n-PFOS accounted for the highest proportion of PFOS(71.0%),followed by 5m-PFOS(8.0%),iso-PFOS(7.9%),4m-PFOS(6.7%),3m-PFOS(4.1%),lm-PFOS(2.3%).Compared with the composition of PFOS in the serum of newly married women,placental transmission was observed in PFOS in pregnant women,and the transmission efficiency was?m2-?1 m->3m->4m-?5m->iso->n-.There was a correlation between the age of pregnant women and the exposure of PFASs.The levels of PFASs were different in different age groups.There was a significant correlation between BMI and glucose metabolism in pregnant women(P<0.001).Increased BMI and the concentrations of n-PFOA and PFPeS in serum adversely affected glucose metabolism.Exposure of two PFOS substitutes(6:2 Cl-PFESA and 8:2 Cl-PFESA)did not affect glucose homeostasis in pregnant women.Different cohort studies have different conclusions,but it can be speculated that exposure to PFASs affects glucose homeostasis in pregnant women.