巴西坚果中含有高于其它食物1000倍的放射性元素镭和钡（补上的译文）

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原文来源：[url=http://www.orau.org/PTP/collection/consumer%20products/brazilnuts.htm]http://www.orau.org/PTP/collection/consumer%20products/brazilnuts.htm[/url] Brazil Nuts

It has been known since the 1930s that Brazil nuts contain relatively large concentrations of barium (approximately 0.1 ? 0.3% by weight) - in our laboratory we measured the barium content in the meat (endosperm) of the nut at close to 0.3%. 从20世纪30年代，我们就已经知道，巴西坚果中的钡含量相当地大（以体重计，大概0.1-0.3%）。我们在实验室里测定巴西坚果胚乳中的钡含量接近0.3%。 That Brazil nuts also contain high levels of radium was first reported in the 1950s (Turner et al 1958). 在20世纪50年代，Turner等（1958）报道在巴西坚果含有高浓度的镭。 Barium and radium are group II elements and their chemical behior is very similar. 在元素周期表中，钡和镭都属于第II A族元素，它们的化学性质很相似。

[ 本帖最后由 ccaipecom 于 2008-3-17 10:12 编辑 ]

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Although the radioactivity is not high enough to be detectable with a simple survey instrument, a one to five minute count on the powdered meat of the nut with a pancake GM or ZnS detector connected to a scaler will indicate that the beta and alpha activities are significantly above background.
虽然简单的检测器无法检测到放射能，但是，用盖革计数管（GM）或ZnS闪烁检测器对坚果果肉粉末进行检测，仪器每分种会发出1-5下的“滴滴”声，这就表明，粉末中的β和α射线的活性比周围环境中有高很多。

Brazil nuts are the seeds of Bertholletia excelsa, a large tree that is grown in various parts of world, not just Brazil.  The nuts, in groups of 12 to 25 much like the sections of an orange, form the globular (4-6? diameter) fruit of the tree.  It is not true, as is sometimes thought, that the high concentration of radium in Brazil nuts is due to elevated levels of the uranium and/or thorium series in the soil in which the tree grows. The accumulation of the radium (and barium) is due to the very extensive root system of the tree. For what its worth, measurements by Penna-Franca et al indicated that higher radium concentrations are found in the lees and cork of the tree than in the nut.
巴西坚果是Bertholletia excelsa（一种大树，在全球很多地方均有种植，并不仅限于巴西）的种子。这些坚果以12-25个为一簇，像橙子的囊瓣一样，成球状（直径4-6cm）。人们认为，巴西坚果内的高含量的镭是因为果树所生长的土壤中含有大量的铀或钍系。其实，不是这样的。坚果中的镭和钡的聚积是由果树的延伸根系造成的。由Penna-Franca等的检测结果可知，在果树的叶子和软木中检测到了比坚果中更高含量的镭。
The Brazil nut has a high lipid (ca. 60%) and protein (ca. 15%) content. The calcium content is ca. 0.2%.
巴西坚果含量大量的脂肪（大约60%）和蛋白质（大约15%）。其钙含量约达0.2%。

Radium Content 镭含量
As might be expected, the reported concentration of Ra-226 and Ra-228 vary, but overall, the radium concentrations in Brazil nuts are 1000 times higher than those in other foods. The following are representative of some of the measurements that he been performed:
如我们所料，报道的Ra-226和Ra-228的浓度存在差异，但，总体上来说，巴西坚果中的镭含量是其它食品的1000倍。以下是一些有代表性的检测结果：

Turner et al (1958): approximately 1.8 pCi/g  Ra-226.
Turner等（1958）：大概1.8pCi/g Ra-226。

Penna-Franca (1959):  approximately 2 pCi/g Ra-228
Penna-Franca（1959）：大概2pCi/g Ra-228。

Penna-Franca et al (1968):      
0.075-3.6 pCi/g Ra-226 in the nut  (3.1-113.5 pCi/g in ash of nut)
0.16- 3.6 pCi/g Ra-228 in the nut  (5.3-114.5 pCi/g in ash of nut)
Penna-Franca等（1968）：
坚果中，0.075-3.6 pCi/g Ra-226，坚果灰分中，3.1-113.5 pCi/g；
坚果中，0.16-3.6 pCi/g  Ra-228, 坚果灰分中，5.3-114.5 pCi/g。

Smith (1971):  up to 6.6 pCi/g Ra-226 in the nut.
Smith (1971): 坚果中的Ra-226高达6.6pCi/g。

Gabay and Sax (1969) determined that most of the radium of ingested Brazil nuts was not retained by the body.
Gabay 和Sax（1969）发现，人们因食用巴西坚果而摄入的镭，大部分不会残留于体内。

References 参考文献
Drury et al. Radioactivity in Food Crops. ORNL-5963. 1981.
Eisenbud, M., Gesell, T.  Environmental Radioactivity.  Academic Press. 4th edition; 1997.
Gabay, J.J., Sax, N.I. Retention of radium due to  ingestion of Brazil Nuts.  Health Physics 16: 812-813; 1969.
Smith, K.A.  The Comparative Uptake and Translocation by Plants of Calcium, Strontium, Barium, and Radium.  Plant and Soil 34:369-379; 1971.
Turner, R.C., Radley, J.M. Mayneord, V.W.  The Naturally Occurring Alpha Ray Activity of Foods.  Health Physics 1: 268 -  275; 1958.
Penn-Franca, et al.  Radioactivity of Brazil Nuts.  Health Physics 14: 95-99; 1968.

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呵，终于把欠下的作业还上了