In the United States (US), Federal and State agencies have established radiological public exposure limits and remedial action ("clean up") criteria for naturally occurring radionuclides (NORM-primarily for uranium and thorium series radionuclides). Often, these criteria are intended to control human exposure to what is referred to in the US as technologically enhanced naturally occurring radioactive material (TENORM). This can be any naturally occurring radioactive material for which the potential for human exposure has been enhanced due to anthropogenic (human activities), e.g., removal from its "place in nature," and/or processed in some way resulting in concentration. In some cases, the values of these regulatory criteria can be similar to or even less than those levels of exposure and those concentrations of NORM that exists in nature independent of any previous human activity. The potential variability of NORM radionuclides in the soil and rocks can be significant, even over relatively short distances or depths due to factors such as geology, hydrology, and geochemistry. Given this, it is important to recognize that defining "the radiation background" for purposes of establishing and/or comparing remedial action criteria and/or exposure limits requires recognition of the specificity at the location(s) of interest, not in other geological and/or mineralogical regimes several miles away. The purpose of this paper is to demonstrate this variability for comparison to exposure levels and concentrations being defined in the US as levels above which require regulatory control and / or above which are being defined as an "unacceptable risk." The primary background exposure component of specific interest here is the annual dose contribution from terrestrial radiation exposure, i.e., from uranium and thorium series radionuclides in the ground, excluding radon inhalation. The exposure sources being controlled by some US regulatory limits are primarily associated with the primordial radionuclides in soil. The average annual terrestrial component of background can vary by upwards of a few tenths of a mSv across the US that can be several times higher than the applicable exposure limits. This can result in "unacceptable risk" or "remedial action" concentration criteria statistically equivalent to or less than the background concentrations of these same primordial nuclides. The statistical and analytical uncertainties of distinguishing naturally occurring radionuclides (i.e., NORM) from those resulting from anthropogenic (human caused) activities (i.e., TENORM) can be quite challenging and in some cases may be technically impossible. Consideration must be given to the relationship of the amount of actual total risk avoidance achieved if any, relative to the traditional health and safety risks of construction and associated construction and waste management costs for remedial activities, so that a practical and scientifically based approach for development of these criteria can be achieved.

中文翻译：

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美国天然放射性物质的陆地本底与补救标准之间的关系。

在美国 (US)，联邦和州机构制定了自然产生的放射性核素（NORM - 主要针对铀和钍系列放射性核素）的放射性公共暴露限制和补救措施（“清理”）标准。通常，这些标准旨在控制人类接触美国所谓的技术增强型天然放射性物质 (TENORM)。这可以是任何天然存在的放射性物质，其人类暴露的可能性由于人为（人类活动）而增强，例如从其“自然位置”去除和/或以某种方式进行处理导致浓缩。在某些情况下，这些监管标准的值可能类似于甚至小于自然界中独立于任何先前人类活动而存在的暴露水平和 NORM 浓度。由于地质、水文学和地球化学等因素，即使在相对较短的距离或深度内，土壤和岩石中的 NORM 放射性核素的潜在变异性也可能很大。鉴于此，重要的是要认识到，为了建立和/或比较补救措施标准和/或暴露限值而定义“辐射背景”需要认识到感兴趣位置的特异性，而不是其他地质和地区的特异性。 /或几英里外的矿物学状况。本文的目的是证明这种可变性，以便与美国定义的暴露水平和浓度进行比较，高于该水平需要监管控制和/或高于该水平被定义为“不可接受的风险”。这里特别感兴趣的主要背景暴露成分是来自地面辐射暴露的年剂量贡献，即来自地下的铀和钍系列放射性核素，不包括氡吸入。美国一些监管限制所控制的暴露源主要与土壤中的原始放射性核素有关。美国各地的年平均陆地成分变化可能高达十分之几毫西弗，可能比适用的暴露限值高出几倍。这可能导致“不可接受的风险”或“补救措施”浓度标准在统计上等于或小于这些相同原始核素的背景浓度。将天然存在的放射性核素（即 NORM）与人为活动产生的放射性核素（即 TENORM）区分开来的统计和分析不确定性可能非常具有挑战性，并且在某些情况下可能在技术上是不可能的。必须考虑所实现的实际总风险规避量（如果有）与传统的建筑健康和安全风险以及补救活动的相关建筑和废物管理成本之间的关系，