The Effects Of Tetrabromobisphenol A On Ingestion, Metabolism And Antioxidant Defense System Of Calanus Sinicus

Tetrabromobisphenol A（TBBPA） is currently one of the most widely utilizedbrominated flame retardants（BFRs）. In recent years, TBBPA as a new type ofpersistent organic pollutants （POPs） gets more and more concerned. Calanus sinicusis characteristic species of copepods in the Northwest Pacific continental shelf area,and its population dynamics is directly related to fishery harvest or not for its widelydistributed as fish bait. The toxic effects of pollutants on C. sinicus can be used as anindicator of the evaluation of the ecological effects of pollutants. In this paper, theeffects of TBBPA on ingestion, respiration, ammonia excretion and antioxidant anddefensive systems of C. sinicus are studied. The main experimental conclusions asfollows:1.The acute toxicity exposed test shows that TBBPA has acute toxicity on C.sinicus. The96h-LC₅₀and its95%confidence limit is0.4276（0.324⁰.564） mg·L^-1.2. The concentration of sublethal toxicity experiment is set according to the96h-LC₅₀. Changes in ingestion, respiration and ammonia excretion rates are studiedon C. sinicus exposed to TBBPA through water. The experiment inclues three stages.After exposed in48h, the effect of TBBPA on ingestion, respiration and ammoniaexcretion rates of C. sinicus the impact show a downward trend, and there is not asimple linear relationship between each of them with the concentration. Ammoniaexcretion rate changes by the greatest impact, and the differences between allconcentration groups and control group are significant; only between oneconcentration group of ingestion or respiration rate and control group has significantdifference. Meanwhile, C. sinicus are transferred to the clean seawater after7days,ingestion, respiration and ammonia excretion rates have recovered in varying degrees,to14d, the indicators have recovered to the level of the control group. 3. Feeding is another commom route to contact with contaminants for animals.Platymonas helgolandica has exposed6d to TBBPA in the above concentrationgradient, then feeding C. sinicus as food, ingestion, for testing the impact of dietaryexposure on respiration and ammonia excretion rates. The experiment results showthat different concentrations of the three indicators have been affected, but nosignificant difference compared to the control group. And there is another conclusionthat the growth of P.helgolandica is not obvious under the experimentalconcentrations of TBBPA.4. Antioxidant defense system is an important indicator of pollutants onbiological oxidation stress. Glutathione-S-transferase（GST）, superoxidedismutase（SOD） and glutathione （GSH） are important components of antioxidantdefense system. After exposed0,12,24,36,48,72and96h with Sublethal dose, C.sinicus determination have been randomly picked for testing SOD, GST activity andGSH content. The result shows that SOD, GST and GSH are sensitive to TBBPA,induced by varying degrees, and this inductive effect is not increased with theincreasing of TBBPA concentration. The trends of SOD and GST activity aresynergistic, and there is a higher activity value when exposed36and72hours. Bothactivity of the two enzymes is declined at first and then increased before and after48hours. GST activity and GSH content of the control group is less than all dose groupsat36h.These results show that C. sinicus is sensitive for TBBPA exposure; thoughTBBPA is strong lipophilic, its bioaccumulation seems low; C. sinicus is moresensitive when exposed to TBBPA throug aqueous than through food, and ingestionand energy metabolism is more vulnerable. The lowest concentration of TBBPA inthis paper is closed to the highest detection value in environment, and ingestion,energy metabolism and antioxidant defense system of C. sinicus have all showedtoxic effects, so it can be used as the evaluation index of environmental pollution.