模拟池塘中锶-89的迁移和积累动力学

采用放射性同位素示踪技术研究了核污染关键核素之一——~(89)Sr在水生生态系中的动力学行为。当示踪剂~(89)Sr一次性引入水系后,即向系统内的动植物及底泥迁移,从而使系统各组分中~(89)Sr-Sr的量均随时间变化。结果表明:1.在试验期间,池水中~(89)Sr-Sr的含量随时间减少,6d后由原来的1.76 ppm降至1.01ppm,11d后已不到原来的一半,第35d时只及原始量的30％。2.池水中的~(89)Sr-Sr向系统各组分中的迁移速率和数量因组分的性质而异。比如底泥,1d后由原始的0增加到7.07 ppm,11d后趋向平衡,以后几乎不再增加;~(89)Sr-Sr在鱼和螺蛳体内的含量在试验期间均随时间增加,35d时分别由原始的0增加到18.73ppm和48.28ppm;在处理当天,金鱼藻中~(89)Sr-Sr虽增加较快,由原始的0增至6.68 ppm,但4h后却几乎不再增加。3.水生动植物对放射性锶都有一定的浓集作用,最大的浓集系数分别为:螺蛳94.7,鱼36.7,金鱼藻只有12.6。可见,贝壳类动物对水系中的放射性锶有较强的去污能力。

THE MOVEMENT AND KINETICS OF ACCUMULATION OF STRONTIUM-89 IN A SIMULATED AQUATIC ECOSYSTEM

The dynamic behaviour of 89Sr in a simulated aquatic ecosystem was studied by using ra-diotracing technique.When 89Sr was introduced into water phase of the system,it immediately uptaken by animals,plants,and moved into mud at the bottom of the system,and the concentration of 89Sr in each component changed with time.The results are as follows;1.The quantity of 89Sr-Sr in water phase decreased with time,at the 6th day the concentration of 89Sr-Sr reduced to 1.01ppm from 1.76ppm (the original),at the 11th day it reduced to less than half of the original and at the 35th day only 30% of the original left.2.According to the nature of components,89Sr in water moved into each component of the system with different speed and quantity.The concentration of 89Sr-Sr in mud increased from 0 to 7.07ppm within 24hrs and after lldays it was equibrated.89Sr-Sr in fish and snail changed with time within 35 days after introduction and the concentration in them increased from 0 to 18.73 and 48.28ppm respectively.The concentration of 89Sr-Sr in hornwort increased from 0 to 6.68ppm within 24 hrs,afterwards it kept at the same level.3.It was calculated that the concentrated factor for snail was 94.9,fish 36.8 and hornwort only 12.6.It is obvious that shells have higher capacity to decontaminate the pollution of 89Sr from water.