多环芳烃在小白洋淀挺水植物中的分布、组成及其影响因素

The distributions,composition and their determining factors of polycyclic aromatic hydrocarbons in emergent macrophytes in Small Baiyangdian Lake

利用GC-MS测定了端村小白洋淀5个采样点三种主要挺水植物(荷花、蒲草和芦苇)中16种优控多环芳烃(PAHs)的含量,分析了其分布与组成特征及其影响因素。结果表明:(1)16种优控多环芳烃总量(PAH_(16))在三种挺水植物中的平均干重含量范围为82.5-448.6ng/g(dw),七种挺水植物组织荷叶、荷茎、蒲叶、蒲茎、蒲根、苇叶与苇根中PAH_(16)的平均干重含量分别为448.6ng/g(dw)、129.3ng/g(dw)、292.6ng/g(dw)、166.8ng/g(dw)、82.5ng/g(dw)、141.5ng/g(dw)和90.0ng/g(dw),这些数据表明同种植物的叶中PAHs含量最高、茎中次之、根中最低;PAHs各组份在七种挺水植物中的含量具有显著的正相关关系,反映了PAHs在植物组织中的分布模式极为相似.(2)七种挺水植物组织中,均以低环PAHs为主,中环PAHs次之,高环PAHs很低,其百分比范围分别为66.2%(荷叶)-89%(蒲茎)、10.2%(蒲茎)-32.6%(荷叶)和0.6%(蒲叶)-3.7%(苇根);菲、荧蒽、萘、芴、芘和屈6种PAHs组分在挺水植物组织中的平均百分含量较高,分别为35.3%、15.5%、12.1%、11.7%、9.2%和5.2%,占PAH_(16)的89%.3)PAHs在挺水植物中的含量与植物含脂率具有显著的正相关关系,与PAHs组分的辛醇-水分配系数(K_(ow))以及辛醇-大气分配系数(K_(oa))具有显著的负相关关系.

The contents of 16 priority polycyclic aromatic hydrocarbons （PAHs） in the seven tissues of three species emergent macrophytes from five sampling sites in Small Baiyangdian Lake nearby Duancun Village were measured by GC-MS. The PAHs distribution, composition, and their determining factors were analyzed. The following results were obtained ： （ 1 ） the total dry-weight contents of 16 priority PAHs （ PAHI6 ） ranges from 82.5 to 448.6ng/g（dw） ,with the average contents of 448.6ng/g（dw） in lotus leaves, 129.3ng/g（dw） in lotus stems,292.6ng/g（dw） in cattail leaves, 166.8ng/g（dw） in cattail stem, 82.5ng/g（dw） in cattail roots, 141.5ng/g（dw） in reed leaves and 90.0ng/g（dw） in reed roots. This shows that highest contents are in leaves, followed by stems and roots. The significant positive relations among the contents of PAHs congeners in seven macrophytes tissues are observed ,implying the very similar PAHs distribution patterns among seven tissues. （2） Of 16 priority PAHs, lower molecular weight PAHs are dominant with the percentages varying from 66.2% （ in lotus leaves） to 89% （ in cattail stems）, while the percentages of moderate and higher molecular weight PAHs range from 10.2% （ in cattail stems） to 32.6% （ in lotus leaves） and from 0.6% （ in cattail leaves） to 3.7% （ in reed roots）. Six PAH congeners including phenanthrene （ Phe）, fluoranthene （ Fla）, naphthalene （Nap）, fluorine （Flo）, pyrene （Pyr） and chrysene （Chr） are dominant components with average percentages of 35.3%, 15.5%, 12.1%, 11.7%, 9.2% and 5.2%, standing for 89% of total 16 priority PAHs （ PAH16 ）. 3 ） PAHs contents in emergent maerophytes are observed to be significant positive relations with their lipid percentages, and to be significant negative relations with the octanol-water partition coefficient （ Kow ） and oetanol-air partition coefficient （ Koa ） of PAH congeners.