Composition, distribution and source of N-alkanes in surface sediments from the coast of East China Sea

In this study, the distribution and composition of n-alkanes in 19 surface sediments from the coast of East China Sea were analysed. The results indicate that n-alkanes in surface sediments from the Zhoushan Island mostly display bimodal distributions. The shorter chain n-alkanes have no obvious odd-even predominance, mainly derived from marine phytoplankton and microbes. The longer chain n-alkanes have a strong odd over even predominance, mainly produced by terrestrial. The shorter and longer chain n-alkanes have a similar distribution trend with high contents in central part of the study area, it maybe related to stronger adsorption of organic matter on fine grained sediments. Both the n-alkanes content ratio of terrestrial to marine (ΣT/ΣM) and the content ratio of terrestrial to marine dominant n-alkanes (TAR) have consistent distribution patterns, the spatial distribution have the high values of ΣT/ΣM and TAR in nearshore Zhoushan Island, indicating strong terrestrial inputs. P_mar-aq、ACL、AI、OEP vaules indicated mainly produced by terrestrial higher plants containing about equal amounts of grass and woody plants in the study area and not find the polluted by oil.