鲤鱼对硝基苯的生物积累、消除与代谢研究

BIOCONCENTRATION, ELIMINATION AND METABOLISM OF NITROBENZENE IN CARPS

应用流动式摄取及释放装置，对鲤鱼进行了硝基苯的生物积累、消除、代谢研究．结果表明，鲤鱼对硝基苯浓缩很快，全鱼、肌肉、其它组织中的生物积累曲线均呈现快速增长至峰，后又快速下降至低浓度水平稳态的峰形曲线，释放呈双曲线形，对数作图可得两条不同斜率的直线．与按惰性化学品估算的ＢＣＦ值相比显示出实测值较低、较快的消除速率、以及具有下降过程的峰形曲线．据此３点推测硝基苯在生物浓缩过程中伴有生物转化发生．对于有明显峰形和代谢作用的硝基苯，应用引入生物转化的酶促动力学模式加以描述，取得摄取与消除速率常数，计算得ＢＣＦ值，与前述实测ＢＣＦ值基本相符，支持了发生生物转化作用的推测．该结果尚待深入的代谢研究证实．

Research on the title were carried out using flow through systems. It was indicated that the concentration in fish increased rapidly at the beginning until the summit was reached, then it declined quickly to low level steady state. The bioconcentration factor (BCF, ratio of C f to C w) for the compound were 6.844 (summit) and 0.76 (steady state, or 28.32, calculated as lipid content, lgBCF=1.45), respectively. By logarithmic plotting, two straight lines with different slopes were measured for thd elimination of chemical in fish, the slopes were 37.00 and 0.53 d -1 , respectively. According to the fact that the BCF values was smaller than those calculated based on the regression equations for inert chemicals from the literature (De wolf, 1992), high rate constants of elimination and the peaky uptake curves, biotransformations were inferred to have happened during the bioconcentrations of the chemical. According to the results of the study on NB, and our earlier study on 2, 4 DNT and 2, 6 DNT, a conclusion reached is that there are two important factors effecting the occurrence of peaks in its bioconcentration curves: 1. Metabolism that occurred in liver, gall bladder and intestine influenced the shape of uptake curves in whole fish. 2. Different nitro compounds had different shapes of uptake curves because of their different metabolism in fish. Supposing the biotransformations of NB in fishes adhere to Delayed Enzyme catalytic Logarithmic Kinetics, a model of bioconcentration and dynamic equations reflecting metabolism was set up, then the parameters of Enzyme catalytic Kinetics and rate constants of uptake ( k 1) or elimination ( k 2) were acquired by nonlinear regression for our measured data. The calculated BCFs, namely the ratios of k 1 to k 2, were accord with the measured BCFs, so it demonstrated the occurrence of metabolism we inferred. The rate constants of eliminations obtained included the contribution of metabolism.