| Perfluorinated compounds(PFCs) are widely used as surface treating agents in numerous commercial and industrial field, such as metal plating, food packaging and pesticide reagent and so on.They are closely related to people's daily lives,due to their unique hydrophobic, oil-repellence and high surface activity. In consideration of their environmental persistence, bioaccumulation, high toxicity and long-distance diffusion, PFCs have caused the extensive concern around the world. The typicial, perfluorooctane sulphonate(PFOS) was added to Annex B of the Stockholm Convention on persistent organic pollutants(POPs).The strict restriction would be taken effect on March 26, 2014 in China. In present,studies on PFCs were focused on the water, soil,sediment, animal-origin food,such as eggs,chicken,sea birds, fish, shellfish,human serum, the rodent's tissues such as liver, kidney and blood. However, few concern are the pollution characteristics of PFCs in the atmosphere are, especially for neutral PFCs in the atmosphere.With the rapid development of the economy, in recent years,environmental issues were increasingly prominent and the fog haze weather appear frequently. Therefore, in order to explore PFCs in the Shenzhen atmosphere,the present study fixed up the passive samplers, at 13 air monitoring sites of the Shenzhen environmental monitoring center in winter(sampling time:2014-11-01 ~ 2015-01-31),summer(sampling time:2015-06-20 ~ 2015-09-20) and 25 indoor sites.And in order to provide scientific basis for PFCs contamination control, the study had analyzed the concentration differences of PFCs in Shenzhen atmosphere between in winter and summer, spatial distribution of the PFCs concentration, source of PFCs, the correlation between the PFCs concentration and PM2.5 and PM10, risk assessment of 7 neutral and 15 ionic PFCs,. The major results:(1)Most of PFCs in the Shenzhen atmosphere of indoor and outdoor were neutral PFCs, ionic PFCs as the auciliary pole. PFBS was the major perfluoroalkylsulfonic acids(PFSAs) in the Shenzhen atmosphere,and the whole of perfluoroc arboxylic acids(PFCAs) were greater than ?PFSAs.The spatial distribution of neutral and ionic PFCs in the Shenzhen atmosphere were high levels in northwest area and low concentration in southeast region. And their concentration levels were generally lower than that of the developed countries.On the basis of carbon chain length, ionic PFCs showed the distribution of short(C?6)> middle(6<C?10) >> long(C>10),and neutral PFCs the distribution of 8:2FTOH>6:2FTOH>>Me FOSA> Me FOSE. At the same time, neutral PFCs in the Shenzhen outside atmosphere in summer were greater than that of winter about 19%, and the total content of neutral and ionic PFCs were a general uptrend.(2) The concentrations of 8:2FTOH, 6:2FTOH, PFPe A, PFHx A, PFOA, as the main PFCs of the Shenzhen atmosphere were a positive correlation between PM2.5 and PM10(P<0.05,P<0.01),which may be caused by some certain metal oxides in the atmospheric particulate matter and FTOHs occurring out-phase reaction at atmospheric particles surface. In addition,the correlation coefficient between the content of PFPe A,PFHx A,PFOA and PM10 were greater than that of PM2.5, which may be related to the p H of atmospheric particulate matter and the Ca2+ concentration.(3) The sources of PFCs in the Shenzhen atmosphere of winter and summer were similar.And the major sources,based on the contribution from big to small, were the volatilization of PFCs residual in the daily necessities,the point source of electrochemical industry and the degradation of FTOHs in the winter atmosphere. The degradation of FTOHs in the atmosphere in summer was greater than that of winter. Neutral PFCs in indoor atmosphere were one of the sources in outdoor atmosphere, yet ionic PFCs were less than that of outdoor atmosphere. The pollution levels of PFCs in Shenzhen atmosphere on human health were temporarily not acutely harmful, yet PFCs had enrichment effect and wide varieties, which should be alarming. |
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