Study On The Pollution Characteristics Of Polycyclic Aromatic Hydrocarbons In Seawater Of Liaodong Bay

Polycyclic aromatic hydrocarbons are an important branch of persistent organic pollutants,which have strong teratogenic,carcinogenic,and mutagenic.Polycyclic aromatic hydrocarbons emitted into water environment could cause negative effect to aquatic microorganisms and plankton,and may be enriched along the food chain,and eventually absorbed and digested by humans,endangering our health.In this article,the content of polycyclic aromatic hydrocarbons in seawater of Liaodong Bay is determined.The content of polycyclic aromatic hydrocarbons in dissolved and particle-associated phase of seawater is analyzed.The partition-ratio of polycyclic aromatic hydrocarbons in dissolved and particle-associated phase is analyzed.The temporal and spatial distribution of polycyclic aromatic hydrocarbons,the main source of polycyclic aromatic hydrocarbons in seawater and their potential ecological risks is also analyzed.The conclusions are as follows:(1)The concentration of polycyclic aromatic hydrocarbons in seawater of Liaodong Bay is in the range of 0.08 ng/L ～ 1215.62 ng/L,of which the concentration in the outside sea is in the range of 3.62 ng/L ～ 693.11 ng/L.The contamination degree of PAHs gradually decreases from the coast to the outside sea.The high concentration of PAHs in the open sea is basically distributed in the western of Liaodong Bay;among the coastal functional areas,industrial areas and tourist areas are the hardest hit areas for PAHs pollution.The results indicated that polycyclic aromatic hydrocarbons show significantly seasonal distribution in coastal waters(P<0.05),in which winter>summer>autumn>spring,the concentration in summer is higher than that in autumn and spring in this study.2-ring PAHs accounted for about 50%,3-ring PAHs accounted for about 40%,4-ring PAHs accounted for about 10%,and no more than 5-ring PAHs were detected in this study.The proportion of PAHs in dissolved phase is about28%,and the proportion of PAHs in particle-associated phase is about 72%.The distribution of PAHs in dissolved phase and particle-associated phase does not show a significant seasonal distribution.(2)The ratios of HPAHs/LPAHs,anthracene/(anthracene + phenanthrene),fluoranthene/202 and principal component analysis are used to determine sources of PAHs in seawater of Liaodong Bay.The main source of PAHs is a mixed source of pyrogenic source and petrogenic source,which is mostly urban runoff sources and wastewater treatment plant’s effluents sources.(3)The ecological risk of Liaodong Bay is determined by risk quotients.According to the RQ value,polycyclic aromatic hydrocarbons in the seawater of Liaodong Bay are at medium risk level for a long time,which can pose potential threats to microorganisms and plankton.Some control measures should be implemented quickly to control and reduce the pollution of polycyclic aromatic hydrocarbons and protect the organisms in the Liaodong Bay.