Study On Bio Remediation Potential Of Perinereis Aibuhitensis On Petroleum Hydrocarbon Polluted Coastal Sediment

Marine oil spill accidents occur frequently with the development of offshore oil exploration and shipping.resulting in a large number of marine oil pollution input.After the oil spill,the floating oil in seawater and the residual oil stranding in near-shore sediments would cause damage to marine organisms by blocking gas exchange of seawater and sediment surface,adhering to the body surface,etc..A series of physical and chemical reactions will take place after petroleum pollutants enter into the marine environment,finally oil pollution will settle into the deposited layer.The bioturbation of benthic animals can change the structure of sediment,promote the material exchange between water and deposited layer.Bioturbation process also promotes the migration and release of contaminants in sedimen changes the redox environment of the deposited layer and the structure and vigor of microbial community in the sediment,thereby contribute to the degradation of petroleum hydrocarbon pollutants in the sediment.In this study,we focus on the bioremediation of petroleum pollution in coastal sediment,reserch the toxic effects of crude oil on Perinereis aibuhitensis and the influence of bioturbation on the migration,release and degradation of alkanes and aromaticss in sediment,and evaluate of the bioremediation potential of P.aibuhitensis on petroleum hydrocarbon pollution in coastal sediment synthetically.The results show that the P.aibuhitensis has a higher bioremediation potential for petroleum hydrocarbon pollution in coastal sediment,however,in the case of high pollution,the ecological risks of release and bioaccumulation in P.aibuhitensis of petroleum hydrocarbons should be fully considered.it is mainly reflected in the following four aspects:P.aibuhitensis had strong tolerance to crude oil in sediment.The 50%Lethal Concentrations(LC50)at 30 days of exposure was 60.62 g/kg dry weight.The activity of Catalase(CAT)?superoxide dismutase(SOD)and Glutathione-s-transferase(GST)in P.aibuhitensis tissue fluid were induced invariably when exposed to crude oil in sediment.The activity of GST inhibited when exposed to excessive concentration of crude oil.The concentration of TPH in sediment controlled below 13.26 g/kg dry weight would not affect the vital movement and enzyme activities of P.aibuhitensis.The bioturbation of P.aibuhitensis promoted the migration and release of contaminants in the sediment.The bioturbation of P.aibuhitensis promoted the resuspension of the depostion particles,so the concentration of total suspended particles(TSS)in overlying water was sianificantly increased.At the same time,the bioturbation promoted the release of contaminants into the water,so the TPH concentration in overlying water with P.aibuhitensis bioturbation was 2.56-7.09 times of the control group,and the content of deuterium phenanthrene in the overlying water of bioturbation group was 2.23?2.43 times of the control group.However,under the background of high pollution,there is a certain ecological risk of the release of petroleum hydrocarbons into the overlying water from sediments with the bioturbation of P.aibuhitensis.The bioturbation of P,aibuhitensis significantly increased the oxygen content of sediment,increased the oxido-reduction potential of the sediment and reduced the acid volatile sulfide(AVS)and the total organic carbon(TOC)content of the sediment.In the bioturbation group,the removal rate of alkane components was 31.94%?48.63%,and the removal rate of aromatic components was 25.49%?36.34%,the removal rate of TPH reached 50.13%,and the removal rate decreased with the increased of depth,which may be because the higher oxygen content in surface layer is more conducive to the aerobic degradation of petroleum hydrocarbon by microorganisms.Meanwhile,the bioturbation of P.aibuhitensis significantly promoted the migration of alkanes to the surface layer,and thus promoted the degradation of alkanes;It can promoted the migration of aromatics to deep layer and enhance their deep burial and persistence.The alkane and aromatic hydrocarbon components could be absorbed by P.aibuhitensis,but he aromatic components are more likely to accumulate in P.aibuhitensis.Under the background of high pollution,the bioaccumulation of petroleum pollutants by P.aibuhitensis is very strong and can not be ignored.