Mück K, Sinojmeri M, Whilidal H, Steger F
Austrian Research Center Seibersdorf, A-2444 Seibersdorf, Austria.
Radiat Prot Dosimetry. 2001;94(3):251-9. doi: 10.1093/oxfordjournals.rpd.a006497.
Due to its long physical half-life, and the fact that its long-term mobility in the environment as well as its radiotoxicity is higher than that of 137Cs, the long-term bio-availability of 90Sr in the environment is of importance with regard to the long-term population exposure after fallout from nuclear weapons detonations or a severe reactor accident. It will also substantially influence the time-span required until re-utilisation of highly contaminated territory is possible again. An assessment of the long-term decrease of the activity concentration in all foodstuffs relevant for internal exposure after severe 90Sr fallout was performed. The observed effective half-lives were approximately 1.8-2.1 years in the first 2-3 years after the end of fallout and 8-10 years in the following three decades. This is equivalent to a biological half-life of about 13.2 years and results in a total 50 year dose of 6.2 times the first year exposure. Due to this decline in 90Sr-availability, the average annual activity intake of 90Sr in Austria has decreased from 840 Bq at the climax of the nuclear weapons tests to about 42 Bq in 1997 for adults, and from 500 Bq to about 35 Bq for 1 year old infants. This is equivalent to a 90Sr ingestion dose of 1.2 microSv for adults and 2.5 microSv for 1 year old infants in 1997 or less than 0.4% of the ingestion dose by natural radionuclides in the diet.
由于锶-90的物理半衰期很长，且其在环境中的长期迁移性及其放射性毒性高于铯-137，因此在核武器爆炸或严重反应堆事故产生放射性尘埃后，锶-90在环境中的长期生物可利用性对于长期人群暴露具有重要意义。这也将极大地影响到再次能够重新利用高污染地区所需的时间跨度。对严重的锶-90沉降后所有与内照射相关食品中活度浓度的长期下降情况进行了评估。在沉降结束后的头2至3年中，观察到的有效半衰期约为1.8 - 2.1年，在随后的三十年中为8 - 10年。这相当于生物半衰期约为13.2年，导致50年的总剂量为第一年暴露量的6.2倍。由于锶-90可利用性的这种下降，奥地利成年人摄入锶-90的年平均活度已从核武器试验高峰期的840贝克勒尔降至1997年的约42贝克勒尔，1岁婴儿则从500贝克勒尔降至约35贝克勒尔。这相当于1997年成年人摄入锶-90的剂量为1.2微希沃特，1岁婴儿为2.5微希沃特，或不到饮食中天然放射性核素摄入剂量的0.4%。
