Distribution Of Hydrophobic Pollutants In Sediment From Yangtze Estuary And Adjacent Area And Its Mplication To Sources Of Organic Matter

The distribution of hydrophobic pollutants（Nonylphenol, Polycyclic AromaticHydrocarbons） are surveyed inYangtze Estuary and Zhejiang coastal area, andecology risk are assessed by risk criteria. At the same time, the sources of pollutantsare also analysed through biomarkers, such as PAHs and n-alkanes; Morever, organicmatter source identification from the biogeochemical parameters are compared. Theconclusions are as follows:（1）The concentration of NP in surface sediment in Yangtze Estuary and Zhejiangcoastal area are116.9-559.0ng·g^-1and122.4-460.8ng·g^-1, respectively. Thecharacteristic of NP presents: increase first, and then decrease in the northeast ofChangjiang diluted water, while in the southeast, the NP concentration graduallydecreases from offshore to sea. The concentration of PAHs also generally decreasefrom offshore to sea in Yangtze Estuary, except for station8and station10（124.5oE，31.5oN）, The PAHs distribution in north of Zhejiang coast are influenced byChangjiang diluted water and Qiantang River, the concentration of NP in central andsouthern section decreased gradually from offshore to sea. NP and PAHs in sedimentcore S12（122.9990°E,30.5011°N）ranges from61.7to251.5ng·g^-1and172.7to689.3ng·g^-1, respectively. the vertical variation of NP and PAHs tend to increase frombottom to top in this sediment core. The concentration of NP and PAHs inS4（124.9697°E,32.0087°N） sediment core range from50.8-115.1ng· g^-1and128.2-262.0ng·g^-1, respectively. On the basis of risk assessment, NP and PAHs maycause adverse effects on marine organisms.（2） The concentration of n-alkanes in surface sediment in Yangtze Estuary andZhejiang coastal area vary from1.5to7656.0ng·g^-1d.w., the distribution pattern ofn-alkanes in this study are not regular, the range of CPI13-22and CPI23-32is0.52-0.72and1.13-2.81, meanwhile, the TARHC（except for station5,7,24） does not exceed1and LMW/HMW ratio is higher than1（except for station5,7,9,24）, it indicates then-alkanes in sediments mainly orginate from marine input. The content of n-alkanes in sediment core S12（122.9990°E,30.5011°N） is76.7-1895.6ng·g^-1d.w., the value ofCPI13-22is less than1, the ratio of TARHCand LMW/HMW are0.01-0.11and5.4-37.8,respectively, this result suggests marine input dominate in this sediement core. Thecontent of n-alkanes in sediment core S4（124.9697°E,32.0087°N） is0.62-404.5ng·g^-1d.w., the value of CPI13-22is also less than1in this sediment core, the ratio ofLMW/HMW ranges from0.5to40.8, the TARHCis less than1（except4-6and6-8cmlayer）, it indicates the alkanes in this sediment core mainly orginate from terrestrialand marine input.（3）The content of TOC and TN in surface sediment are0.08%-1.73%and0.01%-0.21%, respectively, the TOC/TN ratio in surface sediment ranged from2.8to12.9with an average value of7.5, C/N ratio in most samples ranged from4to10, itsuggested a predominant marine origin for organic matter in studied area. In addition,the C/N ratio is higher than10in few station adjacent to Yangtze Esutary, thisindicates the organic matter is influenced by terrestrial input. The C/N ratio insediment core S12（122.9990°E,30.5011°N）varied from7.3to11.7, it suggestsorganic matter mainly originates from marine input. In sediment core S4（124.9697°E，32.0087°N）, the C/N ratio varied from3.0to20, the organic matter present terrestrialinput and marine autogenic source.（4） The contrastive analysis of biomarker parameters（Phe/An, C/N, LMW/HMW,CPI） between pollutants and geochemical parameters suggests: the organic matter instudied area mainly orginates from marine input; the organic matter in sediment coreS12（122.9990°E,30.5011°N） and S4（124.9697°E,32.0087°N） orginate fromterrestrial input and marine autogenic. The correlation analysis among biomarkerparameters suggest: the pollutants and C/N ration are consistent in indicatingsources of organic matter.