放射性污染植物修复中超富集植物的数值评价

Numerical Assessment of Hyperaccumulator for Phytoremediation of Radionuclide Contamination

目前超富集植物在放射性污染植物修复评价体系中还没有明确的核素富集量限定值,借鉴辐射环境评价方式,明确放射性污染低剂量概念,推算达干预水准时的植物富集系数,结合放射性废物管理规定,计算富集系数应达到的水平,提出了重要核素的超富集植物评价的新的量值概念;建立修复年限模式,讨论了一定生物量和生物富集系数对修复年限的影响。结果表明,根据上述因素导出的各重要核素的超富集植物最低富集系数略有不同,分别是Cs-137:0.70、Sr-90:0.86、Co-60:2.89、Pu-239:0.26、Am-241:0.21、Cm-244:0.12、U-235:0.18、U-238:0.052。良好的超富集植物,其富集系数应再提高一个数量级。

Currently there isn＇t a definite minimum accumulation of radionuclide in hyperaccumulator for phytoremediation of radionuclide contamination. Based on environmental radiological assessment, the range of low level radionuclide contamination was defined and the bioaccumulation factor was calculated under intervention level. With radioactive waste management, it was concluded in terms of remediation significance that bioaccumulation ought to be reached. New digital qualification of hyperaccumulator of some critical nuclides in numerical assessment was proposed. A model of time required in phytoremediation was proposed and influence of bioaccumulation and plant mass＇ factor on remediation time was discussed. Results showed that the minimum bioaccumulations of hyperaccumulators were different for various important radionuclides, with corresponding values as Cs-137 0.70, Sr-90 0.86, Co-60 2.89, Pu-239 0.26, Am-241 0.21, Cm-244 0.12, U-235 0.18 and U-238 0.052. Bioaccumulation of each critical radionuclide should be increased one magnitude for a good hyperaccumulator.