Taylor D M
University of Wales Cardiff, Department of Chemistry, Wales.
Appl Radiat Isot. 1995 Nov;46(11):1245-52. doi: 10.1016/0969-8043(95)00167-c.
Although the current world inventory of plutonium is overwhelmingly man-made, it is important to recognize that 244Pu was a primeval radioelement and that 239Pu is formed continuously by spontaneous fission of 238U; the atom ratio U:Pu being about 10(11):1. It has been calculated that the human body has always carried a base load of, perhaps 10(3)-10(5) atoms (< 0.2 amol) of natural plutonium. Since 1945, the release of 239Pu into the environment from atmospheric nuclear weapons testing has added to this base load a civilization-related load which, at approximately 300 fmol, is at least 5 orders of magnitude greater. Within the human body plutonium is deposited mainly in the liver and skeleton where it appears to be retained tenaciously with half-times of many years. Based on 1970-1980 levels, environmental plutonium may give rise to alpha-particle radiation doses of approximately 3-7 microSv/a in human bone and approximately 10-20 microSv/a in liver, doses which from our present understanding of the radio-and chemical toxicity of plutonium are far too small to cause any recognizable health effects.
虽然目前世界上钚的存量绝大多数是人造的，但必须认识到，钚-244是一种原始放射性元素，钚-239则由铀-238的自发裂变持续生成；铀与钚的原子比约为10¹¹:1。据计算，人体一直携带着天然钚的本底负荷，约为10³至10⁵个原子（<0.2阿托摩尔）。自1945年以来，大气层核武器试验向环境中释放的钚-239给这一本底负荷增加了与文明相关的负荷，约为300飞摩尔，至少比本底负荷大5个数量级。在人体内，钚主要沉积在肝脏和骨骼中，似乎会长期留存，半衰期长达数年。根据1970 - 1980年的水平，环境中的钚可能会使人体骨骼受到约3至7微希沃特/年的α粒子辐射剂量，肝脏受到约10至20微希沃特/年的辐射剂量，就我们目前对钚的放射性和化学毒性的了解而言，这些剂量远远太小，不会造成任何可识别的健康影响。
