Study On The Biological Toxic Effects Of Combined Pollution Of PAHs And Heavy Metals In The Marine Environment Based On Enzymatic Activity

The pollution in marine environment is not an effect of a particular pollutant, rather a complicated,cross-interacted consequence related with various factors.A single pollutant mechanism can not explain the mixed effects of multi-pollutants,and evaluation standards based on single pollutant effects can not objectively reflect the environmental quality.Therefore,the only way to the solution of marine environmental problems and to eliminate the pollution is to understand the ocean pollution from the viewpoint of combined pollution.Based on this,this peper conducted an exploring study on the pollution effect of the combination of two typical pollutants:PAHs and heavy metals in the marine environment.The main research contains of the present paper are:Firstly,we established two methods to test the activity of ethoxyresorufin-O-deethylase(EROD) based on traditional method and the plate reader.Through comparing the two opproachs,we found that the plate reader-based is more efficient,and then we used this method to conduct a series of single- and combined-pollution tests.Secondly,under lab conditions,using Tilapia as research objects,and four heavy metals(Cd²⁺,Cu²⁺,Hg²⁺, Zn²⁺) and four PAHs monomer(BaP,IP,Phe,Flu)as objective pollutants,we conducted a series of different concentration(50 ng/L-100 ug/L),single and pair-wise in vitro exposure experiments.Through testing and comparing single pollutant effect on hepatic EROD activity in Tilapia,we study the effects of the combined-pollution. The results shows that,(1) For strong-response of PAHs monomers(BaP,IP,Phe) alone,when heavy metal ions(Cu²⁺,Zn²⁺,Cd²⁺,Hg²⁺) are also present,the strong induction effect of PAHs single-pollution was obviously inhibited,except for Hg²⁺ and BaP/Phe con-effect group.(2) For the co-effect of heavy metal(Cu²⁺,Cd²⁺,Hg²⁺) and PAHs monomer IP, the characteristics of single-pollution generally persists.(3) Under the combined pollution of PAH monomer Flu and heavy metal,no inhibition on EROD activity,as observed under co-existence of PAHs monomer and metal ions,was observed,in contrary,a induction effect on EROD was shown.(4) For two kinds of PAHs monomers showing induction and suppression effects on the EROD activities,their combination with heavy metal basically shows a converse trend compare with PAHs single-pollution.Briefly,PAHs monomers showing induction effects under single-pollutions(BaP,IP,Phe) often show suppression on the activity when they co-exist with metal ions;those PAHs Flu showing suppression activities,show an induction trend when they co-exist with metal ions.This paper established the the plate reader based detection system of EROD activity,which could be used as biomarkers to study the biological toxic effects of environmental pollutants,and have a broad practical future in the ocean biochemistry inspection work.What's more,we conducted the pioneer research on the combined effect of different pollutants,which has important significance in the testing and assessing the toxic effect of typical pollutants,and truly reflecting the real environments.