Distribution and migration of 95Zr in a tea plant/soil system

Zr-95 is a primary radionuclide in the radioactive liquid efflux from a pressurized water reactor and one of the main radionuclides released after nuclear accidents. The fission yield of Zr-95 is as high as 6.2%, however, its environmental behavior has not been well documented. An experiment was conducted to evaluate the accumulation and distribution of Zr-95 in a tea plant/soil system. Zr-95 was accumulated primarily in the trunk of tea plants after being taken up front the soil. The radioactivity concentration of Zr-95 in the trunk increased slowly with time, then it reached a dynamic equilibrium 14 days after application. The radioactivity concentration of Zr-95 in the other parts of the tea plant was very low; only slighter greater than the detection limit. The results indicated that Zr-95 was not readily translocated in the tea plant. About 98.9% of applied Zr-95 was found to concentrate in the upper 5 cm layer after being sprayed onto the soil surface. The results indicated that Zr-95 Could not readily move downwards with percolating water due to strong adsorption to surface soil. (C) 2005 Elsevier Ltd. All rights reserved.