Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States.
Environ Sci Technol. 2010 Dec 1;44(23):8855-62. doi: 10.1021/es1025799. Epub 2010 Oct 29.
Our objectives in this study are to quantify the discharge rate of uranium (U) to the Columbia River from the Hanford Site's 300 Area and to follow that U downriver to constrain its fate. Uranium from the Hanford Site has variable isotopic composition due to nuclear industrial processes carried out at the site. This characteristic makes it possible to use high-precision isotopic measurements of U in environmental samples to identify even trace levels of contaminant U, determine its sources, and estimate discharge rates. Our data on river water samples indicate that as much as 3.2 kg/day can enter the Columbia River from the 300 Area, which is only a small fraction of the total load of dissolved natural background U carried by the Columbia River. This very low level of Hanford-derived U can be discerned, despite dilution to <1% of natural background U, 400 km downstream from the Hanford Site. These results indicate that isotopic methods can allow the amounts of U from the 300 Area of the Hanford Site entering the Columbia River to be measured accurately to ascertain whether they are an environmental concern or insignificant relative to natural uranium background in the Columbia River.
我们的研究目的是量化从汉福德 300 区排入哥伦比亚河的铀（U）排放量，并沿着河流追踪 U 以确定其归宿。由于该地点进行的核工业过程，汉福德场址的 U 具有可变的同位素组成。这一特征使得有可能利用环境样品中 U 的高精度同位素测量来识别即使是痕量污染物 U，确定其来源，并估计排放量。我们对河水样本的数据表明，每天有多达 3.2 千克的 U 可以从 300 区进入哥伦比亚河，这只是哥伦比亚河携带的溶解天然背景 U 总负荷的一小部分。尽管在距离汉福德场址下游 400 公里处被稀释至天然背景 U 的 <1%，仍可以检测到源自汉福德的非常低水平的 U。这些结果表明，同位素方法可以准确测量进入哥伦比亚河的汉福德 300 区 U 的数量，以确定它们是否对环境构成关注，或者相对于哥伦比亚河天然铀背景是否微不足道。
