渤海中部油气开采区石油烃环境质量评价及源解析

Environmental quality and source identification of petroleum hydrocarbons in the surface sediment of the oil and gas exploration zone in the central of Bohai Sea

对渤海中部油气开采区表层沉积物中的石油烃含量进行了环境质量评价,分析了正构烷烃和多环芳烃分子组成特征,并对其来源进行了解析.结果表明,石油类浓度为12.5—860μg·g^(-1)之间,污染指数为0.61—41.97;随着与采油平台距离的增加,平台周边海域石油烃含量和污染水平呈现降低的趋势;沉积物沉积时为缺氧还原的沉积环境.正构烷烃的分布特征和甾萜烷生物标志化合物表明,源自大陆高等植物和海洋浮游生物的烷烃共存于渤海近代沉积物中,石油类产品和化石燃料燃烧产物对其贡献不能忽视;石油平台站位PAHs主要来自石油的直接输入,其它站位主要来自燃烧源.

The concentrations of petroleum hydrocarbons from the surface sediments,collected from oil and gas exploration area in central Bohai Sea were measured to investigate the spatial distributions,analyze the sources according to the component characteristics of n-alkane and polycyclic aromatic hydrocarbons（PAHs）,and evaluate environmental quality. The results showed that the petroleum hydrocarbons contents in surface sediments ranged from 12. 5 μg·g^-1to860 μg·g^-1,and the pollutant standard index（PSI） was in the range of 0. 61—41. 97. The concentration and PSI in sediment decreased with the distanced from the oil drilling platform. The sediment environment was anoxic reduction. The distribution of n-alkanes and sterane,terpane biomarkers indicate that the alkanes from higher plants and marine plankton coexist in the sediments of Bohai Sea. Petroleum products and fossil fuel combustion products should not be ignored for modern sediments of Bohai Sea. PAHs in sediment from oil platform stations are mainly from thedirect input of oil,while other stations mainly from combustion sources.