【摘要】 利用高分辨率气质联用测定北京市大气沉降样品中的二噁英(PCDD/Fs).结果显示,5个样品的总浓度为332—3950pg·g-1和6.9—85pgTEQ·g-1.降雪样品浓度高于其它样品,且不同采样点样品呈现不同的分布特征.2,3,4,7,8-PeCDF是主要的TEQ组分.大部分样品同族体浓度以PeCDFs最高,其次是OCDD.∑PCDDs<∑PCDFs,二者之比为0.25—0.56.PCDD/Fs沉降通量为121pgTEQ·m-2.month-1.北京背景土壤PCDD/Fs组成与大气沉降极为相似.更多还原

【Abstract】 Five Beijing atmospheric deposition samples were collected, which included four total deposition samples and one snow sample. According to EPA 1613, PCDD/Fs were analyzed by HRGC-HRMS. The levels were 332—3950 pg·g-1and 6.9—85 pgTEQ·g-1. The concentration and TEQ of PCDD/Fs in snow sample was higher than the others.Patterns of PCDD/Fs in different deposition samples were compared.2,3,4,7,8-PeCDF contributed the most percent of TEQ in the five samples. PeCDFs was the predominant homologue in Beijing deposition samples followed by OCDD. Concentration of PCDDs was higher than PCDFs. And the ratio of ∑PCDDs and ∑PCDFs ranged from 0.25 to 0.56. According to the average year atmospheric deposition in China,PCDD/Fs average deposition flux was estimated to be 121 pg TEQ·m-2·month-1. The average PCDD/Fs patterns of Beijing background soil resembled the atmospheric depositions very much.更多还原