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某核设施低放废水按活度水平分别排至蒸发池和戈壁滩。1976～1978年和1988～1990年调查研究了蒸发池周围和极低放废水流经地区的一般生态环境和主要放射性核素的食物链转移。结果表明:(1)在低放废水排放影响下,一个相对稳定的特定生态系统已经生成;(2)蒸发池和极低放废水流经地区的沉积物、土壤、动植物组织中的放射性核素含量与对照区比较有明显升高,可检出核素主要有~(60)Co,~(90)Sr,~(137)Cs,其次为~(65)Zn,~(134)Cs,~(144)Ce,~(155)Eu和~(239)Pu,蒸发池水生物核素含量较极低放废水流经区约高3个量级;(3)低放废水排放导致居民照射的关键核素为~(137)Cs,关键途径是猎食蒸发池水鸟。按极端保守假设估计,居民个人摄入~(137)Cs的最大量占居民摄入年限值的50％。正常饮食习惯下,低放废水排放所致居民照射剂量的贡献可以忽略。极端情况下,候鸟迁徙造成放射性物质远距离扩散的最大量估计为10~7Bq·a~(-1)。
Low-level waste water from a nuclear facility is discharged to evaporation ponds and Gobi Desert respectively according to the activity level. From 1976 to 1978 and from 1988 to 1990, the general ecological environment and the food chain transfer of major radionuclides around the evaporation ponds and very low discharge wastewater were investigated. The results show that: (1) a relatively stable specific ecosystem has been formed under the influence of low-level wastewater discharge; (2) radionuclides in the sediments, soils, animals, and plants that flow through evaporation ponds and very low level waste water (60) Co, ~ (90) Sr and ~ (137) Cs, followed by ~ (65) Zn and ~ (134) Cs, ~ (144) Ce, ~ (155) Eu and ~ (239) Pu. The content of biological radionuclides in the evaporation pond is about three orders of magnitude higher than that of the wastewater flowing through the pond. (3) The key nuclide is ~ (137) Cs, the key way is to hunt the waterfowl in the evaporation ponds. According to the extreme conservative assumption, the maximum amount of ~ (137) Cs inhaled by individual residents accounts for 50% of the inhabitant’s intake. Under normal dietary habits, the contribution of inhabitant doses caused by low level waste water discharge can be neglected. In extreme cases, the maximum amount of long-range diffusion of radioactive material caused by migratory birds is estimated to be 10 ~ 7Bq · a -1.