Economic Shellfish Research On Heavy Metals And Kinetic Characteristics Of Bioconcentration

It is studied for the bioconcentration of four heavy metals (As, Hg, Cd, Pb) by three kinds of marine mollusc organism (Venerupis philippinarum, Mytilis edulis, O.gigas thunberg)in the lab. And the kinetic parameters (k1, k2, BCF, B1/2) are obtained by using the non-linear regression, based on the semi-static and the static two-compartment model. The main contents is as followed:1 The improve and the application of the semi-static and the static two-compartment models:Semi-static two-compartment model: The experiment is divided into two phases: The uptake phase is described by the equation ofAnd the clearance phase is described by the equation ofThe kinetic parameters (k1, k2, BCF, B1/2) are obtained through the non-linear regression on the above two equations.Static two-compartment model: On the base of improved Banerjee method (1984), the concentration variation of heavy metals in the control and the sample is determined in the same conditions and at the different experiment time, then the concentration in the organism is calculated through it indirectly. The kinetic parameters are obtained by using non-linear regression with the bioconcentration model as followed:1 The discussion about the semi-static two-compartment and the kinetic parameters obtained through it.The results of the bioconcentration of 4 heavy metals by 3 species of marine molluscs show that (1) The As amount bioaccumulated by the 3 species is very smallunder the condition of our experiment, and the remarkable bioconcentration occur under high concentration of heavy metals. (2) The CAmax increases with increase the metal concentration in the water, while uptake rate constant (ki) and the bioconcentration factor (BCF) are decreased with the increase the metal concentration in the water. (3) The biological half-life of Cd is longer the that of Hg, Pb, As. (4) The order of the BCF of 3 species to Hg, Cd, Pb is that Mytilus edulis >=O.gigas thunberg > Venerupis philippinarwn.(5)The BCF of Hg is higher than that of As, Cd, Pb, shows that Hg is more concentrated by the 3 species.(6)CAmax is in direct proportion to the concentration of water shows that the 3 species are the strong net accumulators. Because they can reflect the degree of the environment pollution, they are regarded as the biomonitors of the environment.3 The discussion about the static two-compartment and the kinetic parameters obtained through it.The kinetic parameters of bioconcentration of Mytilus edulis on Hg are obtained: ki: 3.824-20.96; k2: 0.00886-0.07154; BCF: 292.9-431.7. Compared with the kinetic parameters obtained through semi-static two-compartment, we found the values have some difference, and the reason is being further studied. But the static method is simple and more obtained. It shortens the experiment circle, and economizes the experiment fee and can calculate the uptake rate of the shell needless determined the content of the shell by chemical method, so this method is under further discussion.