渤海典型海域表层沉积物正构烷烃特征比较

Normal alkanes charateristics in the surface sediments from typical Bohai Sea areas

对渤海典型海域表层沉积物正构烷烃特征进行比较研究.分别采集葫芦岛市近岸海域(1#)、东营市近岸海域(2#)、营口市近岸海域(3#)9个站点的表层沉积物样品,经索氏提取、柱净化后进行GC-MS分析.结果表明,各站位都表现为双峰型,显示了陆源与海源双重贡献特征,但主导峰各不相同;正构烷烃含量(∑n-alk)均值分别为5.43μg.g-1、2.27μg.g-1、4.30μg.g-1;三海域碳优势指数CPI、奇偶优势指数OEP、姥鲛烷和植烷比值Pr/Ph等特征比值基本相同,指示混合来源及中性偏氧化的沉积环境;C31/C19均值分别为11.19、4.51、6.73,短/长链比值L/H均值分别为0.50、1.48、1.31,类脂物比值TAR均值分别为3.61、1.03、1.19,综合显示葫芦岛市近岸海域正构烷烃来源主要为陆源高等植物,而营口及东营近岸海域沉积物正构烷烃更多来源于内生浮游生物源及石油源,三海域沉积物受人类污染影响程度从高到低分别为2#海域(东营)>3#海域(营口)>1#海域(葫芦岛市),且东营近岸海域沉积物受石油污染特征明显.这些特征都与3个海域周边城市发展与污染输入特征有直接的关系.

The concentration,composition and characteristic of n-alkanes in the surface sediments collected from 9 sampling sites in three typical Bohai Sea areas,Huludao（1#）,Dongying（2#） and Yingkou（3#）,were studied.The samples were Soxhlet-extracted with the mixture of 1 ∶1（V/V） dichloromethane/hexane and analyzed by GC-MS after purification and concentration.The n-alkanes distribution pattern of the nine sites was all double-peak cluster,which suggests sources from both terrestrial and marine origin.But the most abundant homologue was not the same in different sites.The average n-alkane concentrations are 5.43 μg · g-1,2.27 μg · g-1 and 4.30 μg · g-1 dry weight in Huludao,Dongying and Yingkou,respectively.Carbon Preference Index（CPI）,Odd-Even Predominance（OEP） and the ratio of Pristane/Phytane（Pr/Ph） for the three sea areas are similar,which shows mixed source and neutral and oxidative deposition conditions.The average L/H ratios are 0.50,1.48,1.31;C31/C19： 11.19,4.51,6.73;TAR： 3.61,1.03,1.19 in Huludao,Dongying and Yingkou,respectively.Comprehensive analysis of various parameters shows that the source of n-alkanes in Huludao sea area surface sediments is continental higher plant,and zooplanktonic and petrolic is the main source of n-alkanes in Yingkou and Dongying sea area.