Oil Fingerpring Charactistics Of The Typical Coastal Sea Sediments In Bohai Sea

The paper takes the three typical waters of the Bohai Sea as the object of study, including Dongying coastal waters of Laizhou Bay, Huludao and Yingkou waters of Liaodong Bay. Oil content of sediments were measured. Meanwhile, the spatial-temporal variation of each index was discussed also. On this basis, qualitative and quantitative research on n-alkanes and PAHs of sediments samples were studied further. Using the characteristic ratio, their sources and instruction meanings were discussed. It provides a scientific basis to judge the degree of sediment oil pollution and to further improve the oil fingerprint identification technology.1) Concentrations of n-alkanes (n-C9to n-C35) vary from3.22to9.45μg·g-1with an average5.33μg·g-1dry weight in the sedimental samples of Huludao coastal waters, concentrations of n-alkanes (n-C8to n-C33) vary from2.65to5.30μg·g-1with an average3.88μg·g-1dry weight in the sedimental samples of Yingkou coastal waters, and concentrations of n-alkanes (n-C9to n-C33) vary from2.18to2.43μg·g-1with an average2.27μg·g-1dry weight in the sedimental samples of Dongying coastal waters. Compared with other waters, the n-alkanes content in the sediments of Huludao coastal waters is much higher.2) n-Alkanes distribution patterns of all positions were characterized by one model: double peak-cluster, which means double sources from terrestrial and marine origin. The average value of CPI, Pr/Ph,Σ-Alk/C16, TAR ratio is2.07,1.37,25.63,3.48, respectively, in Huludao coastal waters. All of these three indices suggest that the terrestrial contributions are higher than marine sources. The average value of CPI, Pr/Ph,Σ-Alk/C16, TAR ratio is2.11,1.40,11.38,1.14, respectively, in Yingkou coastal waters, and the average value of CPI, Pr/Ph, Σ-Alk/C16, TAR ratio is2.21,1.50,9.88,1.03, respectively, in Dongying coastal waters. Comprehensive analysis of various parameters shows that the study area is threatened by both terrestrial inputs and petroleum hydrocarbons contaminations, which may be related to river discharging and port shipping.3) The concentrations of16PAHs in Huludao coastal sediments range from320.9to576.4ng·g-1, with the average of442.6ng·g-1, which are mainly composed of2-3rings, the concentrations of16PAHs in Yingkou coastal sediments range from335.0to612.6ng·g-1’with the average of431.3ng·g-1, and the concentrations of16PAHs in Dongying coastal sediments range from223.3to720.6ng·g-1,with the average of391.6ng·g-1. The relative proportions of16PAHs in all stations are similar, and the2-3ring PAHs play a most important role in all the stations. According to ratio analysis (Phe/Ant, Flu/Fly+Pyr), PAHs contaminations showed a mixed PAH input pattern, including oil pollution, coal burning, and wood combustion.4) MERM-Q was employed to analyze ecological risk of PAHs in the surface sediments from Huludao, Yingkouand Dongying offshore area. The result showed that ecological risk of all stations was low. The mean PAH ERM-Qs for all stations none exceeded the value of0.1, indicating that the potential combined ecological risks of PAHs in surface sediments were generally low.