Florou H, Savidou A, Chaloulou C
National Centre for Scientific Research Demokritos, Institute of Nuclear Technology-Radiation Protection, Athens, Greece.
J Dairy Sci. 1996 Sep;79(9):1679-82. doi: 10.3168/jds.S0022-0302(96)76532-3.
The present study evaluated after the Chernobyl nuclear accident the activity of 90Sr in commercial bovine milk sampled monthly from 1987 to 1994. Monthly mean activities (0.04 to 1.25 Bq/L) were comparable with those reported for other countries of the European Union (0.05 to 0.9 Bq/L), but maxima were higher, and the range of values was wider. Milk samples were also compared against samples of bovine milk in Greece that were collected before the Chernobyl accident during the period from 1969 to 1983 (0.04 to 1.37 Bq/L) and from 1985 to 1986 (0.04 to 0.30 Bq/L). The data were fit exponentially utilizing the chi-square statistic. The goodness of fit for the curve was 65%. Based on this result, the effective half-life of 90Sr in milk was estimated to be 308 +/- 57 d, which is very short compared with the physical half-life of 10,410 d for 90Sr. Since the second half of 1992, the decay curve of the measured mean activity approximated a threshold of 0.09 +/- 0.03 Bq/L, which is close to the low limit of detection by beta-scintillation.
本研究评估了切尔诺贝利核事故后1987年至1994年每月采集的市售牛乳中90Sr的活度。月平均活度（0.04至1.25 Bq/L）与欧盟其他国家报告的活度（0.05至0.9 Bq/L）相当，但最高值更高，且数值范围更宽。还将牛奶样本与希腊在切尔诺贝利事故前1969年至1983年期间（0.04至1.37 Bq/L）以及1985年至1986年期间（0.04至0.30 Bq/L）采集的牛乳样本进行了比较。利用卡方统计量对数据进行指数拟合。曲线的拟合优度为65%。基于此结果，估计牛奶中90Sr的有效半衰期为308±57天，与90Sr的物理半衰期10410天相比非常短。自1992年下半年以来，实测平均活度的衰减曲线近似于0.09±0.03 Bq/L的阈值，这接近β闪烁检测的下限。
