Savannah River National Laboratory, Savannah River Site, Aiken, SC.
US Geological Survey, Columbia Environmental Research Center, Columbia, MO.
Health Phys. 2019 Jul;117(1):20-27. doi: 10.1097/HP.0000000000001041.
The biotic exposure and uptake of radionuclides and potential health effects due to breccia pipe uranium mining in the Grand Canyon watershed are largely unknown. This paper describes the use of the RESRAD-BIOTA dose model to assess exposure of small rodents (n = 11) sampled at three uranium mine sites in different stages of ore production (active and postproduction). Rodent tissue and soil concentrations of naturally occurring uranium (U, U, and U), thorium (Th, Th, and Th), and radium (Ra) radioisotopes were used in the dose model. The dose assessment results indicated that the potential internal, external, and total doses to rodents were below the US Department of Energy's biota dose standard of 1 mGy d. As expected, tissue concentrations of U, U, and Th were in approximate equilibrium; however, Ra results in tissue were 1.25 to 5.75 times greater than U, U, and Th tissue results for 10 out of 11 samples. Soil at the three sites also displayed Ra enrichment, so it is likely that the Ra enrichment in the rodents was from soil via typical activities (i.e., burrowing, incidental ingestion, bathing, etc.) or by dietary uptake of translocated Ra. The results suggest that Ra is more mobile in this environment and bioaccumulates in these rodent species (e.g., in bones via the bloodstream). Internal dose accounting suggests that Ra is the radionuclide of most concern for rodent exposure and health.
布雷西亚管铀矿开采对大峡谷流域内生物的辐射暴露和吸收，以及由此产生的潜在健康影响在很大程度上是未知的。本文描述了使用 RESRAD-BIOTA 剂量模型来评估在铀矿开采的不同阶段（活跃期和停产期）的三个矿区采集的小型啮齿动物（n = 11）的暴露情况。啮齿动物组织和土壤中天然存在的铀（U、U 和 U）、钍（Th、Th 和 Th）和镭（Ra）放射性同位素被用于剂量模型。剂量评估结果表明，啮齿动物的潜在内部、外部和总剂量均低于美国能源部的生物剂量标准 1 mGy d。正如预期的那样，U、U 和 Th 的组织浓度处于近似平衡状态；然而，对于 11 个样本中的 10 个样本，Ra 在组织中的结果比 U、U 和 Th 组织中的结果高出 1.25 至 5.75 倍。三个地点的土壤也显示出 Ra 富集，因此啮齿动物中 Ra 的富集很可能是通过典型的活动（即挖掘、偶然摄入、沐浴等）或通过易位 Ra 的饮食摄入从土壤中产生的。结果表明，Ra 在这种环境中具有更高的移动性，并在这些啮齿动物物种中生物累积（例如，通过血液流进入骨骼）。内部剂量核算表明，Ra 是对啮齿动物暴露和健康最令人关注的放射性核素。
