Gilbert R O, Engel D W, Smith D D, Shinn J H, Anspaugh L R, Eisele G R
Computational Sciences Department, Pacific Northwest Laboratory, Richland, WA 99352.
Health Phys. 1988 Mar;54(3):323-35. doi: 10.1097/00004032-198803000-00010.
Estimates are obtained of the fraction of ingested or inhaled 239+240Pu transferred to blood and tissues of a reproducing herd of beef cattle, individuals of which grazed within fenced enclosures for up to 1064 d under natural conditions with no supplemental feeding at an arid site contaminated 16 y previously with Pu oxide. The estimated (geometric mean [GM]) fraction of Pu transferred from the gastrointestinal tract to blood serum was about 5 x 10(-6) (geometric standard error [GSE] = 1.4) with an approximate upper bound of about 2 x 10(-5). These results are in reasonable agreement with the value of 1 x 10(-5) recommended for human radiation protection purposes by the International Commission on Radiological Protection (ICRP) for insoluble Pu oxides that are free of very small particles. Also, results from a laboratory study by Stanley (St75), in which large doses of 238Pu were orally administered daily to dairy cattle for 19 consecutive days, suggest that aged 239+240Pu at this arid grazing site may not be more biologically available to blood serum than fresh 239+240Pu oxide. The estimated fractions of 239+240Pu transferred from blood serum to tissues of adult grazing cattle were: femur (3.2 X 10(-2), 1.8; GM, GSE), vertebra (1.4 X 10(-1), 1.6), liver (2.3 X 10(-1), 2.0), muscle (1.3 X 10(-1), 1.9), female gonads (7.9 X 10(-5), 1.5), and kidney (1.4 X 10(-3), 1.7). The blood-to-tissue fractional transfers for cattle initially exposed in utero were greater than those exposed only as adults by a factor of about 4 for femur (statistically significant) and of about 2 for other tissues (not significant). The estimated (GM) fraction of inhaled Pu initially deposited in the pulmonary lung was 0.34 (GSE = 1.3) for adults and 0.15 (GSE = 1.3) for cattle initially exposed in utero (a statistically significant difference), which may be compared with the expected fraction of 0.11 at the study site using the ICRP lung model for humans.
估算了摄入或吸入的239+240Pu转移至肉牛繁殖群血液和组织中的份额。这些肉牛个体在一个16年前被钚氧化物污染的干旱场地，于自然条件下在围栏内放牧长达1064天，且没有补充饲料。从胃肠道转移至血清的钚的估算（几何均值[GM]）份额约为5×10−6（几何标准误差[GSE]=1.4），近似上限约为2×10−5。这些结果与国际放射防护委员会（ICRP）为人类辐射防护目的推荐的、针对不含极小微粒的不溶性钚氧化物的1×10−5的值合理相符。此外，斯坦利（St75）的一项实验室研究结果表明，在该干旱放牧场地，老化的239+240Pu对血清的生物学可利用性可能并不高于新鲜的239+240Pu氧化物，该研究中连续19天每天给奶牛口服大剂量的238Pu。从血清转移至成年放牧牛组织的239+240Pu的估算份额为：股骨（3.2×10−2，1.8；GM，GSE）、椎骨（1.4×10−1，1.6）、肝脏（2.3×10−1，2.0）、肌肉（1.3×10−1，1.9）、雌性性腺（7.9×10−5，1.5）和肾脏（1.4×10−3，1.7）。对于在子宫内就开始接触钚的牛，与仅成年后才接触钚的牛相比，血液到组织的份额转移在股骨方面大约高出4倍（具有统计学显著性），在其他组织方面大约高出2倍（无显著性）。对于成年牛，吸入的钚最初沉积在肺中的估算（GM）份额为0.34（GSE=1.3），对于在子宫内就开始接触钚的牛为0.15（GSE=1.3）（具有统计学显著性差异），使用ICRP针对人类的肺部模型，可将其与研究场地预期的0.11的份额进行比较。
