我国大气背景点颗粒物PAHs分布特征及毒性评估

选择我国自北向南4个国家大气背景监测站(吉林长白山、山西庞泉沟、湖北神农架和广东南岭),于2013年4个季度采集了环境空气PM2.5和PM10样品,采用超声波乙腈萃取-超高压液相色谱分析16种多环芳烃.结果表明,4个大气背景点的PM2.5和PM10中∑PAHs浓度分别为0.09~25.42ng/m3和0.13~30.16ng/m3,与国内外大气背景点基本处于同一浓度水平,空间分布特点为庞泉沟>长白山>神农架>南岭,季节分布特点为庞泉沟和神农架春季、冬季,长白山的春季,以及南岭冬季明显高于所在背景点的其他季节.PM2.5和PM10中BaP和∑PAHs在低浓度范围内均呈现显著的线性相关性.除了长白山冬季和南岭夏季的3环PAHs比例较高外,其余季节的背景点以4环和5环PAHs为主,主要为荧蒽、芘、苯并(a)荧蒽.通过BaP当量进行了致癌性和致突变性评价,结果显示庞泉沟春季和冬季颗粒物的∑BaPTEF和∑BaPMEF相对较高,分别为1.81~2.74ng/m3和2.92~4.36ng/m3, 对所在区域的PAH污染状况需要关注.

Characteristics and toxicity assessment of airborne particulate polycyclic aromatic hydrocarbons of four background sites in China

PM2.5 and PM10 were sampled in the ambient air of four national background sites (Changbaishan, Pangquangou, Shennongjia and Nanling) from north to south in China during four seasons in 2013. Filter samples were pretreated by ultrasonic extraction with acetonitrile and sixteen polycyclic aromatic hydrocarbons (PAHs) were analyzed by ultrahigh-pressure liquid chromatography (UHPLC). The concentration variation of PAHs in PM2.5 and PM10 of four background sites were 0.09~25.42ng/m3 and 0.13~30.16ng/m3, respectively. The PAHs concentration level of four background sites is similar to the other background site in China and foreign countries. The degree of spatial variation of PAHs was ranked as: Pangquangou>Changbaishan>Shennongjia>Nanling. The seasonal variation was that PAHs concentration in spring and winter of Pangquangou and Shennongjia, spring of Changbaishan, winter of Nanling were higher than others. There was a linear correlation between BaP and ∑PAHs of low concentration in both PM2.5 and PM10. PAHs were mainly composed of 4 and 5-ring PAHs (such as fluoranthene, pyrene, benzo (a) fluoranthene) in most seasons of background sites despite of the winter of Changbaishan and summer of Nanling in which the proportion of 3-ring PAHs was high. The toxicity assessment of PAHs was determined by benzo(a)pyrene equivalent for carcinogenicity (∑BaPTEF) and mutagenicity (∑BaPMEF). The result showed that the toxicity in spring and winter of Pangquangou (1.81~2.74ng/m3 and 2.92~4.36ng/m3) was much higher than that of other seasons of background sites. It is necessary to pay more attention to the relative area which Pangquangou site represents.