黄河三角洲滨海滩涂多环芳烃分布及风险评估

Distribution and Ecological Risk Assessment of Polycyclic Aromatic Hydrocarbons in Tidal Flats in Yellow River Delta, China

采集黄河三角洲滨海滩涂湿地7个样地共120个表层沉积物样品,分析沉积物中16种优先控制的多环芳烃(PAHs)的含量和来源,并评价其生态风险。结果表明,沉积物中16种PAHs的平均含量为415 ng/g,其中PAHs以2~3环为主,属于中等污染水平。空间分布上,黄河口附近样地低于黄河三角洲北部和南部滨海滩涂湿地表层沉积物中PAHs含量,但不同样地间及距低潮区不同距离间PAHs含量均差异不显著。特征比值法分析表明,不同样地中PAHs来源不同,位于黄河三角洲南部的样地6表层沉积物中PAHs主要来源于草木和煤燃烧,而位于黄河三角洲北部的样地2表层沉积物中PAHs主要来源于石油燃烧、生物质燃烧和原油污染,其它样地的PAHs来源以原油污染为主。采用毒性当量因子评价法(TEQ)和平均效应区间中值商法(m-ERM-Q)分析,发现不同样地表层沉积物中∑PAHs的TEQ值均小于40 ng/g,且15种PAHs的m-ERM-Q值均低于0.1,表明PAHs的生态风险较低。

In order to study the contamination level,distribution characteristic,sources and ecological risk assessment of polycyclic aromatic hydrocarbons(PAHs)of intertidal flats in the Yellow River Delta(YRD),120 samples of 7 sample sites were collected from the surface sediments in coastal tidal flats with same vegetation(Suaeda glauca)of the YRD.The results show that the mean of PAH concentrations was 415 ng/g,with two-and three-ring PAHs predominant in sediments.The pollution status of PAHs in coastal tidal flats of the YRD was at a moderate level.The content of PAHs in the surface sediments in sample site near the Yellow River Estuary was lower than that in north and south of the YRD,while there was no significant difference in PAHs content between different sample sites and different distances from the low tidal level to dam.Source analysis showed that the main source of PAHs in surface sediments of coastal tidal flats in the YRD were different.PAHs in surface sediments of coastal tidal flats at sample site 6 in the south of the YRD was mainly derived from grass,wood and coal combustion,while that at sample site 2 in the north of the YRD was mainly derived from petroleum combustion,grass,wood and coal combustion and petroleum,and that at other samples was mainly derived from petroleum.TEQ value of∑PAHs were all less than 40 ng/g and the m-ERM-Q values were all less than 0.1,indicating that the ecological risk of PAHs in surface sediments of coastal tidal flats of the YRD was relatively low.