| Shellfish is a kind of soft corals double shell marine animal, which distributes worldwide along the coast, with fixed lifestyle. In their bodies, there is high accumulation of their environment pollutants, such as petroleum hydrocarbons. Many countries regard mussels and oysters shellfish as contaminants instructions in the biological monitoring, Chlamys farreri is an important economic shellfish in China's offshore, outputting 1.2×107 tons, accounting for 25% of total aquatic products and more than 80% of total seawater aquaculture in China. People can endanger their health and safety by eating the derived shellfish from petroleum hydrocarbons carcinogenic substance especially the PAHs.Semi-static exposure experiment is adopted to research the scallop on the accumulation of petroleum hydrocarbons and respond to changing under the oil pollution. The main work and results of the thesis are summarized as follows:1. The extraction condition of ultrasonic method is optimized, the concertration of the petroleum hydrocarbons in the whole scallop's body and its different tissues from HuDao and ShaZiKou are tested by using the method established accordingly.The appropriate extraction condition of ultrasonic method is using methylene chloride as extracting agent and elution agent, setting 160W as ultrasonic power, running 5mins, and repeating 3times. Under this condition, the petroleum hydrocarbons concentration of scallop from HuDao is 164.1mg/kg dw, and it is 119.5mg/kg dw from ShaZiKou; the tested pollution index of scallop from HuDao is 1.3, and it is 0.95 from ShaZiKou. The higher petroleum hydrocarbons'concentration of scallop from HuDao than ShaZiKou indicates that the scallop from HuDao is more seriously polluted by petroleum hydrocarbons. The concentration of the petroleum hydrocarbons from different tissues are, gills > digestive gland > mantle> muscle. The petroleum hydrocarbons contained in scallop's body from ShaZiKou are mainly phenanthrene which is a three aromatic ring PAHs, and the normal alkanes between C15 and C28. And the different tissues from the HuDao are mainly naphthalene which is a two aromatic ring PAHs, and the normal alkanes between C13 and C35. The pollution sources of HuDao area performs as a variety of oil components, including lubricating oil, diesel, gasoline, crude oil pollution and so on.2. The water-soluble petroleum hydrocarbons are chosen to make the exposed experiment under 4 different concentrations(control,0.08mg/L,0.21mg/L,0.88mg/L), in order to test the petroleum hydrocarbons concentration of scallop's body atdifferent time, and to analysis the distribution rule of the normal alkanes and the PAH in scallop'body.The regularity of the petroleum hydrocarbons'concentration change in the scallop's body is different. Petroleum hydrocarbon content in the control group, 96.19 ~ 111.60 mg / kg dw range. The petroleum hydrocarbon concentration of scallop from 0.08mg/L group reach to 138.37mg/kg dw, then decreased, reach to maximum 145.19 mg/kg dw at 7d, and 112.89mg/kg dw when the exposed experiment end, within the edible (≤124.5mg/kg dw), suggesting that it's primary for hydrocarbon metabolism in scallops'body. The petroleum hydrocarbon concentration of scallop from 0.21mg/L and 0.88mg/L concentration group increased at first and then decreased, reach to balance at the 4d with different concentrations (68.58 mg/kg dw and 298.83 mg/kg dw) after mixed with the petroleum in water, 204.98 mg/kg dw and 57.39 mg/kg dw which is higher than control group when experiment end. It explains that petroleum hydrocarbons accumulate in the scallop body when pollution levels exceed a certain range.The alkanes contained in scallop's body are mainly C10~C31, the alkanes can be metabolized by scallops are mainly C15~C23, and that can be accumulated are C24~C31. The primary compounds that 2-3 rings are naphthalene and phenanthrene, and≥4 rings are chrysene.3. Comet assay is used to detect the DNA damage that petroleum hydrocarbons make on the Chlamys farreri hemolymph cells, finding that comet tail length and tail moment are also increasing with increasing concentrations of petroleum hydrocarbons during the exposure experiment, which shows a dose - response relationship. The DNA damage of Chlamys farreri in the group of 0.21mg/L and 0.88mg/L is more and more serious with time. After the recovery experiment, the DNA damage is recovered in a certain extent.4. Determined the toxicology index of experimented Chlamys farreri gill and digestive gland tissue, analyzed the MDA content , the changes of glutathione S-transferase(GST),superoxide dismutase (SOD),catalase ( CAT) and glutathione peroxidase (GPx) activity, and its regularity for change in order to learn the toxicology of Chlamys farreri.MDA content and GST, SOD activity of the Chlamys farreri's digestive gland tissue is higher than that of gill tissue, except CAT, because liver tissue contained in the digestive gland is the place for detoxification and metabolism. In the same exposure time, the higher the concentration of petroleum hydrocarbons are, the lower gill's MDA content, and shows a obviously dose- response relationship; the time-response relationship as "decrease-increase- decrease" exists inside the gill's MDA content of every petroleum hydrocarbon concentrations while the time-response relationship as "increase-decrease" exists inside the digestive gland's MDA content following the time to add with pollution stress.The GST activity of gill tissue has no significant change in the control group, it shows the time- response relationship as "increase-decrease" in the group of 0.08mg/L, explains that the gill's GST activity is induced under low concentration, and is restrained with the time prolongs. In the group of 0.21mg/L and 0.88mg/L, it shows the time- response relationship as "decrease-increase-decrease", and the GST activity of digestive gland tissue has no significant change in each group. The gill's CAT activity shows the time-response relationship as "decrease-increase-decrease" as with the digestive gland's in the group of 0.21mg/L and 0.88mg/L, the same as the gill and the digestive gland's SOD in the group of 0.08mg/L and 0.21mg/L. The digestive gland's GPx activity shows the time-response relationship as "increase-decrease" in each group. What is said above, the gill's MDA content and GST activity, the gill and digestive gland's CAT,SOD activity are allowed to be biomarkers.There is a negative correlation between MDA content and SOD, CAT activity; between SOD activity and CAT activity; and as the relationship between MDA content of digestive gland and SOD activity, SOD and CAT. Petroleum hydrocarbon concentrations and SOD as a negative correlation, and CAT as a positive correlation,and MDA content of digestive gland as a negative correlation, and MDA content of gill as a positive correlation.In short, according to the analysis above, the method used to extract petroleum hydrocarbons quickly from chlamys farreri is established; the enrichment effect of chlamys farreri, DNA damage degree, and the active changes of toxicology index affected by petroleum hydrocarbons are researched, which helps us to understand the toxic action and mechanism, and that is able to offer some basic data and technical support for oil spill damage researcher , evaluate the environmental pollution effect etc. |
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