Biomarker Responses To Heavy Metals And Polycyclic Aromatic Hydrocarbons Exposure In Bivalve (Chlamys Farreri)

The thesis is focous on the toxic effect of the typical pollutants in coastal zone, such as heavy metals (Cd, Zn, Pb, Hg and Cu) and polycyclic aromatic hydrocarbons (PAHs). Both in field investigation and lab experiment were carried out to systematically study the distribution pattern and Ecological risk assessment of the mentioned pollutants in Bohai Bay. By a hovel research thought of exposure to the environmentally comparative concentration level, we studied the multi biomarker responses to the environmentally relative concentration levels of heavy metal; "Integrated biomarker responses" index has been used to assessment the multi biomarker response research; biomarkers of antioxidant system and metabolic system were investigated to study the combined toxicity of heavy mental and PAHs; basing on the integration study of polybrominated diphenyl ethers (PBDE) in marine environment, a novel phenomena that the ratio of BDE-183 in environmental sample were high in Chinese samples, it can be used as an eigenvalue to indicate the E-waste pollution in this country. Detail of of the thesis have been list as followed,1, Exposing at an environmentally comparative concentration level of Bohai Bay, Cd and Pb have caused a serious oxidative stress in organism; they show good time-response relationship and dose-response relationship between benzo(a)pyrene exposure and EROD activity; interactive effect can be obviously investigated when the bivalves exposed to the benzo(a)pyrene and heavy metals in combinations, which means that heavy metal may have certain effects on the benzo(a)pyrene(1) Environmentally relevant concentration characteristic of "combined pollution" in Bohai BayThe average concentrations of Cd, Zn, Pb, Hg and Cu in surface seawater were 0.15μg/L,19.86μg/L,1.63μg/L,4.84×10-2μg/L and 2.68μg/L, respectively. There was no clear vertical variation characteristic for heavy metal in seawater of this region. In terms of sediment investigation, the concentration level of Cd, Zn, Pb, Hg and Cu in the surface sediment were 0.15 mg/kg,26.43 mg/kg,16.28 mg/kg,4.25×10-2 mg/kg and 20.80 mg/kg, respectively. The concentration range of∑PAHs was 148.97～375.32 ng/g. Among the 16 PAHs individual anthracene, fluorine and acenaphthene were the main components, which contributing over 50%to the∑PAHs. Basing on the ERL (Effects Range Low) and ERM (Effects Range Median) value, the potential biological risk of the mentioned pollutants in sediments can be evaluated. Results indicated that most of the heavy metals and PAHs were higher than ERL values, except fluorine and acenaphthene were ranged between ERL and ERM values which represent a effect-active range.(2) Multi biomarker responses in bivalve to the exposure of heavy metals and benzo(a)pyrene, dosed alone.When bivalves were exposed to the environmental concentration level of heavy metal (Cd, Zn, Pb, Hg and Cu), they had different responses to different heavy metal. Results showed that the activity of SOD had been significant inhibited by 16.8%and 8.75%after 96 h exposure to Cd and Pb. In terms of CAT and GPx, although all of the five metals we investigated have restricted the enzyme activities, Cd and Pb were the most effective ones, with the inhibitions on the CAT of 31.5%and 28.7%, and on GPx of 40.4 and 62.4%. Since they had a profound inhibition effect on the antioxidant enzyme which resulted in oxidative stress, the MDA level in Cd and Pb exposure groups had been elevated by 33.5%and 60.2%, respectively. According to our study, the Zn, Hg and Cu did not have obvious effect on antioxidant system, but Cd and Pb exposure caused a serious oxidative stress in organism, and the two metals have significantly inhibited the EROD activity as well.Bivalves were exposed to low, middle and high concentration of benzo(a)pyrene for 48h,96h, and 168h to study the antioxidant enzyme and phaseⅠ/phaseⅡenzyme response to this typical toxic pollutant. Among all the biomarker, EROD was the most readable for the pollution status of this pollutant, since there are good time-response relationship, and dose-response relationship between benzo(a)pyrene exposure and EROD activity.(3) Multi biomarker responses in bivalve to the exposure of heavy metals and benzo(a)pyrene, dosed in combinationsWhen the bivalves exposed to the benzo(a)pyrene and heavy metals in combinations, heavy metal may have certain effects on the benzo(a)pyrene induced enzymes, in the terms of EROD, GPx, and GST, all of the five heavy metals have exhibited a antagonism effect on benzo(a)pyrene, especially on the EROD. Although exposed to benzo(a)pyrene, dose only, has significant induced of EROD activity, when exposed to the mixture with the five metals all have reduced EROD activity, even exhibited an inhibited effect when compared with that of control. While in terms of SOD and CAT there was no obvious effect caused by heavy metal.2, Basing on investigation of distribution characteristics, controlling factor and congener pattern of PBDEs in marine system, a novel phenomena that the ratio of BDE-183 in environmental sample were high in Chinese samples, it can be used as an eigenvalue to indicate an E-waste pollution in China.PBDEs, due to their widespread usages as flame retardants and their lipophilicity and persistence, have become ubiquitous in the environment. In this thesis, the available data were summarized and analyze to describe the regional distributions, controlling factors and congener patterns of PBDEs in marine and associated environmental matrixes worldwide. Consistent with the production statue, America and Korea are more contaminated than other parts of the world, while Europe is the least contaminated. Based on the Principal Component Analysis, the congener patterns of sediments are different from those of biota. The former are predominant with the heavy brominated congeners (BDE-209 contributing over 85%to the total load) while the latter abounds with the light ones (BDE-47,-99, and-100 taking about 80%). Noticeable,, the relative high proportion of BDE-183 in Chinese sample can prove effectively that China is being polluted by the e-waste received from developed countries.