Study On Levels Of Perfluoroalkyl Substances In Milk And Eggs From Xinjiang

Perfluoroalkyl substances(PFASs)is not easily degraded and metabolized in human body,and it will show a variety of toxic effects which are harmful to the human health when exposed to a certain dosage.There are many ways for human exposure to PFASs,however,animal-derived foods are the main contributor.Hence,this study developed a method for the PFASs detection and investigated the levels and distribution of PFASs in milk(cow milk and yogurt)and eggs(chicken,duck,goose and quail)produced from Xinjiang by using this method.Furthermore,a preliminary health risk assessment for local residents was conducted.The main content and results for this study are as follows:In the present study,the method for detection PFASs in milk and eggs was developed by using solid-phase extraction combined with liquid chromatography-tandem mass spectrometry(SPE-HPLC-MS/MS).Analytical conditions of HPLC and MS/MS were optimized,C18 chromatographic column was selected and 10 mmol/L ammonium acetate aqueous solution/acetonitrile was used as mobile phase.The pretreatment conditions was optimized as well.For milk samples,the extraction effective of perfluorooctanoic acid(PFOA)and perfluorooctane sulfonate(PFOS)was compared with various extraction solution,sonication time,extraction time and SPE cartridge,the results showed that good recoveries for target compounds would acquire if we chose methanol solution for two times extraction under the sonication time of 40 min,and use the HLB SPE cartridge for purification the extract.For egg samples,the method for extraction and the type of SPE cartridge was optimized,finally,using ion pair extraction and WAX cartridge can achieve relatively good recoveries for 13 PFASs.The method evaluation found that each analytical method all presented good precision and accuracy,which can meet requirements for analysis PFASs in milk and eggs.This study was conducted to measure the levels of PFOA and PFOS in milk and yogurt from Xinjiang and to investigate the average daily intake(ADI)of these two compounds.The results showed that parts of samples have detectable levels of these two compound and PFOS present higher detection rates(39.6% and 48.1%)and mean concentrations(24.5 and 31.8 ng/L)than those of PFOA(33.0% and 37.0%;16.2 and 22.6 ng/L,respectively)in milk and yogurt;the levels of the two compounds in samples from the north regions were higher than the south;on the basis of the milk measurements and consumption data,the ADIs of PFOA and PFOS for Xinjiang adults were calculated to be 0.021 and 0.032 ng/kg/day,respectively;relevant hazard ratios which used for health risk assessment suggesting that no potential health damages were produced by PFOA and PFOS intake via milk consumption in the Xinjiang population.The research work of investigating the levels and distribution characteristics of 13 PFASs in eggs originated from Xinjiang found that the 11 PFASs were all detected in eggs and perfluoro-n-pentanoic acid(PFPeA),perfluorohexanoic acid(PFHxA),PFOA,PFOS,perfluorononanoic acid(PFNA),perfluoroundecanoic acid(PFUdA)are the main compounds.The mean level of PFPeA is highest,and the profile of PFASs in eggs showed that short-chain is dominant;eggs from Urumqi owned the highest ?PFASs concentrations(0.644 ng/g),and Yanqi owned the lowest(0.203 ng/g);there are PFASs pollution to some extent in the four kinds of eggs from Shihezi,and duck eggs presented the highest total concentrations of PFASs(0.417 ng/g),PFOS was detected in each kind of egg yolks,and were not detected in all egg whites;health risk of residents exposed to PFASs via chicken eggs was estimated and the results showed that the levels of PFASs in eggs would not cause imminent damages.