| In order to investigate the bioavailability and the activity of antioxidantenzymes(GSH-Px,GST,POD,SOD,CAT) of petroleum hydrocarbon on Ruditapesphilippinarum,the Ruditapes philippinarum was exposed to the water solublefraction of crude oil(WSF) at different concerntrations (0.1,0.2,0.4,0.8,1.6and3.2mg/L)and discuss the bioavailability of petroleum hydrocarbon and toxic effecton bivalve mollusks.The mainly results are shown below.1The research about the bioavailability of petroleum hydrocarbon onRuditapes philippinarum(1) The experiment of enrichmentThe Ruditapes philippinarum was exposed to the water soluble of crudeoil(WSF) at different concerntrations (0.1,0.2,0.4,0.8,1.6and3.2mg/L).After aperiod of15d, take samples to measure the concentrations of petroleumhydrocarbon in Ruditapes philippinarum.It shows that Ruditapes philippinarum hasa high ability of accumulating petroleum hydrocarbon. Bioconcentration factors(BCF) decreased with the increasing oil concentration in seawater.BCF arerespectively231.20,137.15,113.30,70.46,47.45,30.61. The rate of accumulationincreased with the increasing oil concentration in the seawater and the rate arerespectively1.54,1.83,3.02,3.76,5.06,6.53mg/k/d.(2) The experiment of releasementAfter15-day exposure period,the Ruditapes philippinarum was removed to thenatural sea water. After10-day releasement, the rate of elimination increased withthe increasing oil concentration in seawater and the rate are respectively2.16,2.39,2.57,2.83,3.24,4.63mg/kg/d. It showed that after10-day releasement, the concentration of0.1and0.2mg/L can reture to the nomal level while the otherconcentrations can not.2The influence mechanism of antioxidant enzyme of petroleum hydrocarbonstress upon ruditapes philippinarumThe period of exposure last15days.A series of ruditapes philippinarumsamples were exposed to petroleum. The values of antioxidant enzyme activity weredetermined after1d,4d,8d and15d, respectively. Then the rest samples weretransferred into petroleum-free-seawater. The experiment of restorement lasted10days and test the activity of antioxidant enzyme after1d,5d and8d, respectively.(i) In general, exposing to petroleum affects activities of all kinds ofantioxidant enzymes. Firstly, the laws can be summarized owing to the relationshipbetween exposing time and impact towards five kind concerned enzymes as listedbelow in parallel. The activity of GSH-Px plots the trend of up-down-up accordingto the data from the performances exposed to petroleum; the activity of GST plotsthe trend of up-down-up according to the data from the high concentration ofpetroleum (0.8mg/L,1.6mg/L and3.2mg/L), meanwhile, it plots the trend ofdown-up-down-up according to the data from the low concentration of petroleum(0.1mg/L,0.2mg/L and0.4mg/L);As for POD,it plots the trend of down-up-down-up of the concentration of0.1,0.2,0.4.3.2mg/L while0.8,1.6mg/L showedthe opposite trend; The activity of SOD plots the trend of up-down according to thedata using0.1mg/L and0.2mg/L petroleum, meanwhile it is up-down-up when theconcentration of petroleum is above0.2mg/L; the activity of CAT plots the trend ofup-down according to the data from the performances using all the variedconcentration of petroleum.Secondly, the laws can be summarized owing to the relationship betweendosage and impact towards the enzymes. High concentrations of petroleumenhances the activity of GSH-Px, while low concentrations depresses their activities;regarding GST,3.2mg/L petroleum enhances its activity, while all the otherconcentrations of petroleum depress its activity; according to the data obtained bythe15d’s exposing,1.6mg/L and3.2mg/L petroleum both enhance the activity of POD, at the same time other concentrations of petroleum depress its activities; theactivity of SOD displays the rule of enhanced-depressed according to the data using0.1mg/L and0.2mg/L petroleum, meanwhile it is enhanced-depressed-enhancedwhen the concentration of petroleum is above0.2mg/L;as for CAT, petroleumenhances its activity in a short period, and depressed its activity in a long period.(ii) There are obviously differences among the recovery degrees of theactivities of the five kind enzymes after the ruditapes philippinarum samples wereremoved from petroleum stress, indicating that there is clear threshold value of toxiceffect, which impacts the enzymes activities. For GSH-Px, GST, CAT, POD andSOD, the threshold values, measured by the concentration of petroleum, are0.4～0.8mg/L,1.6～3.2mg/L,0.8～1.6mg/L,>3.2mg/L and>3.2mg/L, respectively.3Integrated Biomarker Responses（IBR）is a approach that can integrate allkinds of biomarkers and evaluate the conditions of pollut comprehensively andobjectively. The correlation coefficient between IBR and the concentration of petroleumis respectively0.7215,0.8265,0.9671,0.5973,0.1533according to the day of1,2,4,8,15. It showed that IBR has significant correlation with the content of petroleum in theday of1、2、4while has not in the day of8、15. It showed that IBRcan preferably reflectthe toxic effect of petroleum hydrocarbon in Ruditapes philippinarum in the short term.And at the same time it menns great importance to evaluate the risk of oil spill. |
PDF Full Text Request