95Zr在鲫鱼体内的分布及在水生生态系统中的消长动态

采用同位素示踪技术研究了鲫鱼对~(95)Zr的吸收和在其体内的分布动态以及95Zr在水生生态系统中的行为特性,并运用非线性拟合方法建立其数学模型。结果表明:(1)从水体中引入的95Zr由于沉降、土壤吸附、被鱼体摄入和金鱼藻的吸收、吸附作用使水体中的95Zr比活度呈快速下降,其消失动态符合二项指数衰减规律,Cw=43.36e-1.7439t 12.85e-0.1467t。(2)金鱼藻对95Zr有较强的吸收、吸附能力,其比活度变化动态(1～28d)符合单项指数衰减规律,Ch=166.69e-0.0361t,其浓集系数(CF值)随时间而增大,至试验结束时(28d)高达321.12。(3)鲫鱼从水体中摄入和吸收95Zr的主要器官是肠胃道(内脏),与水体直接接触而吸附、吸收的95Zr主要集中在鱼鳃和鱼鳍中,肉、骨和鱼卵中的比活度较低(略高于本底水平),表明通过肠胃道摄入和鳃、鳍等组织吸附、吸收的95Zr不易向肉、骨和鱼卵等内部组织输运,指数回归分析表明鲫鱼(全鱼)中95Zr的变化动态符合二项指数规律,C=12.12(e-0.2045t-e-1.4470t).

The Distribution of 95Zr in Crucian and the Dynamics of its Disappearance in a Simulated Aquatic Ecosystem

The distribution dynamics of 95Zr absorbed in crucian and the behavioral trait of 95Zr in an aquatic ecosystem was studied by using isotope-tracer technology, and the mathematical model was confirmed by application of nonlinear regression method. The results showed: 1. The specific activity of 95Zr in water reduced quickly for subsidence, soil adsorption, crucian intake, hornwort's adsorption and absorption. The dynamics of its disappearance accorded with binomial index regression law: Cw=43.36e-1.7439t 12.85e-0.1467t. 2. The hornwort had stronger capacity to absorbing and adsorping 95Zr. The change dynamics of its specific activity accorded with monomial index regression law: Ch=166.69e-0.0361t. Its CF value was increscent with time, which went to 321.12 by the end of the test. 3. The main apparatus of crucian to intake in and absorb 95Zr was intestines and stomach (viscera). 95Zr of adsorption or absorption by direct contact with water mainly concentrated on the gill and fin. The specific activity of 95Zr in meat, bone and roe was lower (just higher than the level of background). All that showed it was not easy for 95Zr taked in by intestines and stomach and adsorped or absorbed by the gill, fin, et al. to transport to inner organ such as meat, bone and roe. Index regression analysis indicated that the change dynamics of 95Zr in crucian (the whole body) accorded with binomial index regression law: Cf =12.12(e-0.2045t-e-1.4470t).