溢油污染物在海底沉积物中的识别与垂向迁移——大连湾海底沉积物研究

Split oil identified and vertical migration in sediment of seabed: Case in Dalian Bay

沉积物插管短柱样品于2013年4月采自大连湾2010年"7·16"溢油事故污染区,BQ050站与BQ007站分别位于生物分散剂和化学分散剂喷洒区。沉积物的可溶有机质含量(沥青A)、有机碳同位素组成(δ^(13)C_(org))和210Pb比活度分析结果表明:喷洒生物分散剂的重污染区(BQ050站),沉积物中TOC含量为0.58%~1.51%,平均为1.15%;δ^(13)C_(org)值为-22.2‰^-20.5‰PDB,平均为-21.74‰PDB;沥青A含量为0.061 5%~0.566 4%,平均为0.174 9%;沥青A/TOC比值为7.0%~34.8%,平均为14.13%;210Pbex比活度存在异常峰值分布,垂向分布特征与沥青A相似;2~16 cm段沉积物的可溶有机质具有明显的外来输入特征。喷洒化学分散剂的较轻污染区(BQ007站),沉积物中TOC含量为0.61%~1.14%,平均为0.87%,除8~14 cm层段外,比BQ050站略低;但沥青A含量与沥青A/TOC比值明显低于前者;δ^(13)C_(org)值较BQ050站轻;210Pbex比活度随柱样深度呈指数衰减,对数相关;外来有机质输入量较低。截至2013年4月,BQ050站溢油污染物在海底下16 cm深度处有特征信号,溢油污染物沥青A组分垂向迁移距离约为15 cm。

Two core sediment samples collected in the area of 16 thJuly 2010 split oil accident by box crab during April 2013. The biological dispersant were used during the split treatment in heavy pollution area. Site BQ050 and Site BQ007 located in the area where biological dispersant and chemical dispersant were used,respectively. The TOC content,soluble organic content（ asphalt A）,δ13Corgvalue and 210 Pbexof sediments were analyzed for identifying the contaminated organic matters. The sediments of Site BQ050 have higher organic matter content（ TOC： 0. 58% ~ 1.51%,mean： 1. 15%; asphalt A： 0. 061 5% ~ 0. 566 4%,mean： 0. 174 9%,up to 0. 566 4% in depth 10 ~ 12 cm）,heavier δ13Corgvalue（-22. 2‰ ^-20. 5‰ PDB,mean：-21. 74‰ PDB）,and higher asphalt A/TOC ratio（7. 0% ~ 34. 8%,mean： 14. 13%） indicating that the organic matter characterized by exotic. Meanwhile,the δ13Corg values of sediments are similar,which shows the same organic input in the depth from 2 cm to 16 cm. The210 Pbexof sediments has the similar distribution to the asphalt A. The sediments of Site BQ007 have much lower asphalt A content and asphalt A/TOC ratio compared to the sediments of Site BQ050,and the210 Pbexdistribution is normal. The content of210 Pbexdecreasing with depth shows the logarithmic correlation. The exotic organic matter is low in the Site BQ007. The split oil（ characterized by asphalt A） has been migrated to about depth of 16 cm in the Site BQ050 until April 2013.