| Perfluorinated compounds(PFCs) are a class of organic fluorine compounds in which all hydrogen atoms attached to carbon atoms are replaced with fluorine atoms. PFCs are widely used in industrial and consumer fields including textile, paper, metal plating, painting and food packaging as surface-active agent because of their hydrophobicity and lipophobicity. PFCs have been closely associated with human production and living. Fluorine atom has the strongest electronegativity and this makes the stability of PFCs. As a result, PFCs are frequently detected in water, soil, atmosphere and biological samplers. The toxicologic study indicated that PFCs have carcinogenicity, hepatotoxicity, and neurovirulence and reproduction toxicity. Considering their distribution and health risk, PFCs have attracted a great attention all around the world and the typical compounds, perfluorooctane sulphonate(PFOS) was added to Annex B of the Stockholm Convention on persistent organic pollutants(POPs), and perfluorooctanoic acid(PFOA) was listed in the 9th batch of substances of very high concern by the European Chemicals Agency, respectively. However, most studies on PFCs focused on their contamination characteristics in water, soil and sediment, with a little attention on atmosphere, especially the non-violate, ionic PFCs in atmosphere, whereas the environment in China is not optimistic, and the haze in atmosphere attracts the biggest concern. In this thesis, passive air samplers were deployed in the Pearl River Delta(PRD) from November, 2013 to January, 2014(winter) and July, 2014 to September, 2014(summer), 13 ionic PFCs species in atmosphere were analyzed using ethyl acetate extraction combined with high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS) in order to study the contamination characteristics of PFCs in atmosphere of the PRD, the contamination characteristics of seasonal and spatial variability, source apportionment and the health risk, which would provide scientific data and basis for understanding the pollution of PFCs in atmosphere of the PRD, health risk and the regional environmental pollution control. The main results of this research are as follows:(1) Short- and medium-chain(C≤10) were the main contamination in atmosphere of the PRD, Σ PFCs was 119 pg·m-3in winter and 148 pg·m-3 in summer, respectively. The main contamition in winter were PFOS(31.9 pg·m-3), PFOA(27.2 pg·m-3), perfluoropentanoicacid(PFPe A)(24.2 pg·m-3) and perfluoroheptanoic acid(PFHp A)(22.6 pg·m-3), while in summer were PFOA(61.3 pg·m-3) and PFPe A(47.9 pg·m-3). The concentration of PFCs was related to the particulate matter(PM) in atmosphere, and the specific result showed there was a positive correlation between PFOS, long-chain perfluoroocarboxylic acids(PFCAs) and PM2.5, PM10. There was different between domestic and abroad with the contaminant characteristics, by contrast, which was related to the industrial structure and the history of PFCs used.(2) There was no significant difference in Σ PFCs between winter and summer of the PRD, andΣ PFCs in winter was lower than that in summer. Great differences in composition of PFCs was found, perfluoroalkyl sulfonic acids(PFSAs) was lower significantly in summer(P<0.05), however, short- and medium-chain PFCAs, except PFHp A, was higher. The reasons for this phenomenon were various, stronger adsorption capacity of PFSAs and long-chain PFCAs to solid substances, the limit of PFOS-using, the degradation of PFCs by ultraviolet ray were considered.(3) Σ PFCs in atmosphere in south PRD was higher than that in north PRD in winter, while west PRD was higher than east PRD in summer, which was related to the wind direction as the PRD belongs to a typical subtropical monsoon climate. The industrial structure and population density led to the phenomenon that higher Σ PFCs in some region.(4) The sources of PFCs in atmosphere showed seasonal variations. The PFCs in winter were dominated by the degradation of PFCs precursor, followed by discharge of PFOS industries including metal plating, textile, fire-fighting, PFOS manufacture, semiconductor industry, and discharge of PFOA industries including PFOA manufacture, petrochemical industry, electron industry. The PFCs in summer were dominated by discharge of PFOA industries, followed by discharge of PFOS industries and the degradation of PFCs precursor, and the last was plating, electron industry.(5) The health risk assessment to PFOS and PFOA showed that the immediate harm was minimal, to which diet, drinking and breath were considered. However, PFCs have a great variety, and have the enrichment effect in human beings, so enough attention was necessary. |
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