Preliminary Studies On Perfluorinated Compounds In Various Typical Environmental Media And Non-occupational Human Serum Of Shanghai

Perfluorinated Compounds(PFCs)are a class of organic pollutants commonly used in global industry and daily life.PFCs have potential hazard to human.There are large numbers of PFCs in the environment due to their widespread use.They are easy to bio-accumulate in the living things.Their contamination to the environment,even the human body,has attracted global concern.In this paper,17 PFCs,including perfluorocarboxylic acids(PFCAs)and perfluorosulfonic acids(PFSAs),were target compounds.A new method for analysis of PFCs with background interference elimination was developed.The method was applied to detect the PFCs in landfill leachate of Shanghai,to study the distribution characteristics of PFCs in the main surface watershed,and to figure out the current occurrence of PFCs contamination levels in human serum.The PFCs potential ecological risk to the aqueous system was also evaluated.Meanwhile,the influencing factors of PFCs serum concentration in non-occupational people of Shanghai were analyzed.The major findings and conclusions are as follows:1.The method for analysis of PFCs with background interference elimination was established.And the major components and levels of PFCs in the leachate of Shanghai Laogang Landfill were detected by using this method which could provide technical support to generate much more accurate PFCs concentrations.The results showed that the main background interference is perfluorooctanoic acid(PFOA),derived from a Teflon protective coating in the liquid chromatograph,which will continuously generate when the Teflon contacts with the organic solvents.And this interference could not be treated as an ordinary blank background deduction because of its unstable signal response.In this study,the background interference was eliminated by using the ZORBAX SB-C18(4.6 × 50 mm,5.0 ?m)column tandem a ZORBAX Eclipse XDB-C18(4.6 × 150 mm,5.0 ?m)column.The front column was used to capture background contamination,and the rear column was used for sample analysis.The sample peak and background contamination peak could be obviously separated.The ammonium acetate was added in mobile phase with concentration at 2 mmol/L.The total time for operation was 10 min.Reproducibility and stability of the method were both good.The method was applied in the detection of PFCs in Laogang landfill leachate.The limit of detection(LOD)was 0.02-0.18 ng/mL,and the major pollutants in the leachate were PFOA and PFBS.The concentration of them were 2185.27-3352.92 ng/L and 3382.00-4831.88 ng/L,respectively.2.In this study,surface water samples were collected from principal watersheds of Shanghai.The pollution levels,distribution characteristics,sources,current occurrence and mass loading of PFCs in the surface water were systematically studied for the first time with high spatial resolution sampling sites in Shanghai.Ecological risk assessment of PFCs was also evaluated.This study could be an important scientific basis for controlling the discharge of PFCs into the environment and protecting surface water in Shanghai.PFCs was detected in all water samples,indicating that these substances were widely distributed in surface water of Shanghai.The concentration of PFOA in surface water was the highest,followed by perfluorobutanesulfonic acid(PFBS),perfluorohexanesulfonic acid(PFHx S)and perfluorohexanoic acid(PFHxA).The concentrations of PFBS were generally higher than those of PFOS.PFOA,PFBS,perfluoropentanoic acid(PFPeA),PFHxA and PFHx S totally accounted for more than 95% of the sum concentration in surface water samples of Shanghai.PFOS and other long-chain perfluorocarboxylic acids(PFCAs)(C > 8)were less frequently detected at low concentration.There might be four types of pollution sources according to the principal component analysis(PCA).They might be household sources,fluorine industry discharge,source of the conversion from long-chain to short chain PFCs and short-chain PFCs pollution source.The sources of the PFCs contamination was supposed as follows: 1)PFOA and perfluorononanoic acid(PFNA)have possible source of biodegradation from the same precursor,2)The distribution of PFCs in surface water in Shanghai was less influenced by atmospheric deposition,3)PFNA and perfluorodecanoic acid(PFDA)may be derived from fluorotelomer alcohols(FTOHs)degradation.The overall contamination trend showed that there is high PFSAs pollution in the northwest of Shanghai,which might originate from the upper reaches of Lake Taihu and the wastewater treatment plants distributed in that direction.PFOS,PFBS and PFHxS pollution trends were also affected.There are three PFOA pollution regions along the Huangpu River in the study area.The analysis of PFCs in one of the three region showed that chemical industrial is a potential source of pollution for PFOA in this region.Compared with other surface water in China or even worldwide,PFOA and PFOS were at middle levels.Mass loading analysis in the surface water revealed that the Huangpu River exhibited relatively large mass loading of total PFCs of 1742.43 kg/year to Yangtze River Estuary.And the predominant PFCs was PFOA with 652.65 kg/year.PFOS had a low potential risk based on ecological risk assessment in the study area.3.The study on the occurrence levels and distribution characteristics of PFCs in human body of Shanghai is relatively scarce,thus there is an urgent need to carry out related research due to their potential hazards.The concentration levels,potential sources and influenced factors of PFCs in non-occupational human serum samples from Shanghai were studied for the first time in this study.The results unveiled that 11 of 17 PFCs were detected in human serum samples of Shanghai,which showed that these PFCs were widely existed in Shanghai non-occupational population.The total concentration of serum samples was between <LOD-99.37 ng/m L.And the major PFCs were PFOA and PFOS,accounting for 49.5% and 34.2%,respectively.Pearson correlation analysis showed that PFBA was not associated with any of the other PFCs,and there was a significant correlation between PFOS and PFHxS.There is a significant positive correlation among PFNA,PFDA,PFUdA,PFDoA,and perfluorotridecanoic acid(PFTrDA)in the human serum,indicating that they might have the similar exposure sources.The PCA showed that the PFCs in human serum of Shanghai could be divided into two components.The component 1 was consist of C8 to C13 PFCs,and the component 2 was consist of C4 to C9 PFCs.Low or high exposure to the PFCs sources might be the reason for PCA results,which was contributed by the long-chain PFCs that were more easily to accumulate in the body compared with short-chain PFCs.The results showed that there was no significant correlation between the concentrations of PFCs and age in this study(p = 0.125-0.951)by Kruskal-Wallis test.Mann-Whitney U test was used to analyze the relationship between workplace and PFCs concentrations.The results showed that there was also no significant correlation between the concentrations of PFCs and the workplaces(p = 0.247-0.861).Therefore,PFCs in human serum of non-occupational populations in Shanghai might acquire from long-term exposure starting from the same period,and might be affected by complex sources.Comparing the PFCs concentrations in human serum from cities in China and worldwide,the results showed that PFOA concentration was at high level,and PFOS was at the middle level in China.The average concentrations of PFOA and PFDA in the human serum of Shanghai were the highest all over the world.