Studies On The Distribution Rule Of Cadmium In The Patinopecten Yessoens Body And The Cadmium Influence On Antioxidant Enzymes Defense System

In the l7 priority researches of the food contaminants ,which are identified by the world health organization, cadmium locats in third. And Patinopecten yessoens ,which belongs to bottom habitat, is much easier to accumulate cadmium. Cadmium can cause certain harm on human body health through the food chain, also can cause harm on marine creatures. It's toxicity mainly manifests in combineding with biological component to constitut metal complex or metal chelates, leading to many enzymes deactivation, making the physiological functions of bioactive molecules restrained and causing poisoning. This paper studies of the cadmium acute toxicity effect in Patinopecten yessoens , the space and time distribution and change rules of cadmium in Patinopecten yessoens body ,the influence of cadmium affecting at antioxidant defense system, by using ecological simulation experiment method. Aims at understanding and grasping the dynamic change regulations of cadmium accumulation, distribution and emission in yessoensis. Aims at providing important scientific basis for the further study of biological mechanism of heavy metal cadmium and for the early warning technology research in aquaculture environment risk .Experimental results are as follows.1. The experiments proves that cadmium is medium toxic to Patinopecten yessoens.And along with the increase of the concentration of cadmium, scallops's sensitivity is strengthened. Patinopecten yessoensis's LC₅₀ in the 96h is 1.73 mg/L ,the 95% confidence interval is 1.58～1.90 mg/L ,and the safe concentration is 0.0173 mg/L .2. The results shows that cadmium is accumulated constantly during the cadmium exposure experiment.And the bioaccumulation in gill,visceral,coat film and muscle increases with the elapse of time,which achieves balance on the 14th day.At this time,the order of their cadmium bioaccumulation(dry weight)and bioaccumulation rate(from large to small) is visceral, gill, coat film and muscle.The dates respectively are 562.93 mg/kg and 40.21 mg/( kg·d^-1),354.27 mg/kg and 25.31 mg/( kg·d^-1),125.36 mg/kg and 8.95 mg/( kg·d^-1),34.49 mg/kg and 2.46 mg/( kg·d^-1). The result shows that due to the particularity of cadmium accumulation, musle is safer to eat than the rest of scallops.3. The cadmium bioaccumulation(dry weight) dropes with the elapse of time during the cadmium elimination experiment. The elimination rate of each organization is high on the 10th day . The elimination rate of muscle is 87.02%.And the rate of gill is 86.10%.The order of their cadmium elimination rate (from large to small) is muscle ,gill, coat film, visceral,while the order of their cadmium elimination speed (from large to small) is visceral, gill, coat film, muscle. The result shows that it is effective for the cadmium elimination to puting Patinopecten yessoensis,which have been exposured to cadmium a short time, into clean salt water.4. The rule of the cadmium bioaccumulation and enrichment coefficient (from large to small) are visceral, gill, coat film and muscle in the same cadmium concentration.And the cadmium bioaccumulation in each tissue increases along with the increase of the cadmium concentration,however the allocation sequence within different organizations isn't affected by it. The enrichment coefficient in the same tissue drops allong with the increase of cadmium concentration. And the muscle's enrichment coefficient is always at the lowest.5. The SOD activity of 0.025 mg/L and above all group increases at first and then decreases. The maximum and minimum values appears on the 3th day,showing a significant difference with the control group(P﹤0.05). The SOD activity of each group decreases on the 6th day and is restrained on the 9th day. The CAT activities of 0.025mg/L,0.05mg/Lå'Œ0.150mg/L group show a significant difference with the control group(P﹤0.05)on the 0.5th day. The CAT activities of each group are restrained on the 6th day.The SOD and CAT activities of Patinopecten yessoensis visceral tissue are sensitive to Cd , presenting inhibit - inducement rule, which can provide molecular ecotoxicology index for early warning of Cd pollution. The GSH-PX activity ,compares with the control group,there is no group showing significant difference.