深圳市大气中PCDD/Fs污染水平初步研究

Determination of Dioxins and Furans in Atmosphere of Shenzhen,China

目的:了解深圳市大气中二噁(PCDD/Fs)的污染水平和分布特征。方法:利用大流量空气采样器分别采集6个采样点的空气样品,每个采样点采集两个平行样品。参照美国环保总局(US EPA Method TO-9A)二噁的检测方法,通过高分辨气相色谱-高分辨双聚焦磁式质谱仪(HRGC/HRMS)对大气样品中17种具有毒性当量因子(TEF)的单体进行了定性和定量分析。结果:∑PCDD/Fs的浓度范围为0.23～11.88pg/m3(平均值为3.84 pg/m3)。毒性当量浓度范围为0.014～0.29 pg I-TEQ/m3(平均值为0.135 pg I-TEQ/m3)。OCDD、HpCDD、HpCDF、OCDF、HxCDF是丰度较大的单体,分别占总浓度的48.21%、15.85%、11.37%、7.40%、6.59%。PCDDs和PCDFs单体浓度(除OCDF之外)均随氯原子取代个数的增加而增大。2,3,4,7,8-PeCDF对总的毒性当量贡献最大,占总毒性当量浓度的38.87%。六个采样点中有三个地点二噁同系物分布显示了"源"的特征,而另外三个地点则显示了"汇"的特征。成人的PCDD/Fs暴露量为0.0023～0.047 pg I-TEQ/kg.day;儿童PCDD/Fs暴露量为0.0052～0.11 pg I-TEQ/kg.day。结论:深圳市大气样品中二噁浓度低于国内一些城市研究水平,而高于日本、欧美国家的研究水平。

Objective： To understand the concentrations and congener profiles of polychlorinated dibenzo-p-dioxins and dibenzfurans（PCDD /Fs） in atmosphere of Shenzhen.Methods： The high-volume air samplers were used to collect the samples in six sampling sites,and every site collect two parallel samples.Reference to the US EPA dioxins detection methods,Ambient air concentrations of the 17 polychlorinateddibenzo-p-dioxins and dibenzofurans considered to be toxic by the World Health Organizations have been measured by HRGC / HRMS.Results： The air concentrations of PCDD / Fs range from 0.23 to 11.88 pg.m-3,with an average of 3.84 pg.m-3.The TEQ concentrations range from 0.014 to 0.29 pg I-TEQ.m-3,with an average of 0.135 pg I-TEQ.m-3.OCDD,HpCDD,HpCDF,OCDF,HxCDF were greater abundance of congeners,account for the total concentration were 48.21%,15.85%,11.37%,7.40% and 6.59% respectively.An increase in the PCDDs and PCDFs（except the OCDF whose concentrations were lower）concentrations was observed as chlorination level increased.2,3,4,7,8-PeCDF was the dominant contributor to toxicity equivalent（TEQ）,account for 38.87%.Three locations in Six sites dioxin homologue distribution showed the＂source＂characteristics,whereas the other sites showed a＂sink＂characteristics.Inhalation exposure to PCDD /Fs were 0.0023 ～ 0.047 pg I-TEQ kg-1.day-1 for adult and 0.0052 ～ 0.11 pg I-TEQ kg-1.day-1 for children.Conclusion： The levels of PCDD /Fs in studied atmosphere samples of Shenzhen was lower than some domestic urban which had researched in China,but higher than the level of Japan,Europe and the United States urban.