北黄海大气多环芳烃干沉降通量研究

Dry deposition fluxes of polycyclic aromatic hydrocarbons in North Yellow Sea

在北黄海沿岸的獐子岛、老虎滩和小麦岛进行为期1 a的大气采样,分析了大气颗粒物和气相中15种多环芳烃(PAHs)的浓度,计算了其沉降通量。结果表明,三个采样点PAHs干沉降通量分别为10 196 ng/(m2.d)(獐子岛)、16 749ng/(m2.d)(老虎滩)和18 982 ng/(m2.d)(小麦岛),且气态PAHs显著高于颗粒态PAHs的沉降通量,说明海洋大气中PAHs的干沉降以气态沉降为主。在采暖期(11月至次年3月),PAHs的沉降通量较高,而非采暖期则较低。气态PAHs沉降在采暖期和非采暖期绝对值相差较大,但均以2+3环PAHs为主;颗粒态沉降的优势化合物在采暖期为4环PAHs,而在非采暖期为5+6环PAHs。

The particle and gas-phase concentrations and dry deposition fluxes of 15 polycyclic aromatic hydrocarbons （PAHs） were determined in the atmospheric samples collected from three sites （Zhangzi Island, Laohutan and Xiaomai Island） in the North Yellow Sea region from Nov. 2008 to Sep. 2009. The results showed the dry deposition fluxes were 10 196 ng/（ m^2· d） （Zhangzi Island）, 16 749 ng/（ m^2· d） （Laohutan Station） and 18 982 rig/（ m^2· d） （Xiaomai Island ）, respectively. The deposition fluxes of gasphase PAHs were higher than particle phase, which suggested that the gas deposition dominates the deposition of PAHs to the sea. The higher deposition fluxes occurred in the heating period （ Nov. to Mar. of next year）. Although the large difference was observed between the heating period and non-heating period,2 ＋ 3 ring PAHs were the dominant compounds in both heating period and non-heating peri od. The 4 ring compounds were dominated in particle PAHs deposition during heating period, while the 5 ＋ 6 ring compounds were mainly associated with non-heating period.