杭州地区城区降雪中全氟化合物的污染特征

Perfluorinated Compounds in Snow from Downtown Hangzhou,China

通过调查杭州降雪中16种全氟化合物(PFCs)的质量浓度,考察了杭州地区大气中PFCs的污染状况.2016年1月20~22日,在杭州市城区及主要郊县建成区共计11个采样点采集降雪样品,应用固相萃取净化、富集与超高效液相色谱-串联质谱联用相结合的方法,测定样品中PFCs质量浓度.所有采样点降雪均有不同浓度的PFCs检出,全部样品共检出包括C_4和C_8全氟烷基磺酸以及C_4~C_6、C_8和C_9全氟烷基羧酸等7种中短链PFCs.ΣPFCs质量浓度范围为2.85~35.1 ng·L^(-1),其中全氟辛酸(PFOA)质量浓度范围2.15~23.0 ng·L^(-1),为主要污染因子,全氟辛烷磺酸(PFOS)检出浓度较低,为0~0.46 ng·L^(-1).与国内外其它地区相比杭州降雪中PFOA含量居于中等水平,PFOS含量则处于相对较低水平.污染物空间分布城区略高于郊县,其中富阳最高,建德和淳安较低.本次调查,在研究区域降雪中普遍检出以PFOA为主较高浓度的PFCs,表明湿沉降已经成为杭州地区土壤、地表水和地下水等生态系统PFCs污染一个不可忽视的污染源,需要有关部门引起足够的重视.研究结果揭示了杭州地区大气中广泛存在以PFOA为主的PFCs污染,大气因素可能已成为当地人群和生态环境暴露PFCs的重要途径之一.

Snow samples were collected from the snow event on January 20-22,2016 from 11 sites in downtown Hangzhou to explore the occurrence of sixteen perfluorinated compounds（ PFCs） in the atmosphere. All samples were prepared by solid-phase extraction with Oasis WAX cartridges and analyzed using ultra performance liquid chromatography interfaced with tandem mass spectrometry（ UPLC-MS/MS）. The results showed that seven medium-and short-chain PFCs including C_4 and C_8perfluorinated sulfonates（ PFSAs） and C_4-C_6,C_8,and C_9 perfluorinated carboxylic acids（ PFCAs） were detected in the snow samples. Total PFC concentrations ranged from 2. 85 to 35. 1 ng·L^（-1）,whereas perfluorooctanoic acid（ PFOA） dominated,with ranges of 2. 15-23. 0ng·L^（-1）,and perfluorooctane sulfonate（ PFOS） was detected at lower levels,ranging from 0 to 0. 46 ng·L^（-1）. As compared to the results from other studies,the PFOA concentrations of the study region were at mid-level and the PFOS concentrations were relatively low. The spatial distribution of PFCs varied,and the pollutant concentrations of the snow samples from the sampling sites located in the urban areas were higher than those in the rural areas. The greatest total PFC concentrations were detected in Fuyang,whereas the lowest concentrations were detected in Jiande and Chun＇an. In this study,the high concentrations of PFCs dominated by PFOA that were measured in the Hangzhou snow samples emphasize the importance of atmospheric wet deposition as one of the sources of PFC contamination in this ecological system and should be addressed. The occurrence of PFCs in the air,indicated by their presence in the snow,suggests that the atmospheric environment may be an important contributor in human and ecological exposure to PFCs by local residents.