The activity concentrations of ²³⁸U, ²²⁶Ra and ²¹⁰Pb were modelled in Pinus sylvestris (Scots pine trees) on a uniform CaF₂ sludge heap in Belgium. The aim of this work is to enhance the knowledge of how transfer factors behave in NORM landfills. The simplest possible model in radioecology is used, which is based on Concentration Ratios (CR-s) measured in equilibrium and activity concentrations of the above-mentioned radionuclides measured in the substrate where pine trees grow. Two alternative CR-s were used: (1) international CR compilations by the IAEA (2014) and (2) CR-s specifically determined for pine trees studied in British Columbia (Mahon and Mathews, 1983). Both CR-s were applied assuming lognormal distributions fitted from data reported in the literature. The results were compared with activity concentrations measured in trees sampled on-site. Modelled concentrations match the measured ones best in the case of ²³⁸U. For the studied NORM waste site, the approach using generic IAEA concentration ratios does not fulfill the conservatism requirement in the cases of ²³⁸U and ²²⁶Ra, as the concentration of radionuclides in trees is underestimated. On the other hand, the ratios from Mahon and Mathews, (1983) produce wide distributions, ensuring conservatism due to larger CR-s. The measured concentrations are narrowly distributed in general, which can be expected on a small sampling site on a uniform substrate. The generic approach outlined here is practical but, as a result of the uniqueness of the site considered, should be applied cautiously in other NORM situations.

在均匀的CaF ₂上对樟子松（苏格兰松树）中的²³⁸ U，²²⁶ Ra和²¹⁰ Pb的活性浓度进行建模。比利时的污泥堆。这项工作的目的是增强对NORM垃圾填埋场中传递因子的行为的了解。使用了放射生态学中最简单的模型，该模型基于在松树生长的基质中平衡测定的浓度比（CR-s）和上述放射性核素的活性浓度。使用了两种替代性CR-s：（1）国际原子能机构（2014）的国际CR汇编和（2）专为不列颠哥伦比亚省研究的松树确定的CR-s（Mahon and Mathews，1983）。假设从文献报道的数据中得出对数正态分布，均应用了两种CR。将结果与现场取样的树木中测得的活性浓度进行比较。在²³⁸的情况下，模拟浓度与测量值最匹配U.对于所研究的NORM废物场，在²³⁸ U和²²⁶ Ra的情况下，使用通用IAEA浓度比的方法不能满足保守性要求，因为树木中放射性核素的浓度被低估了。另一方面，Mahon和Mathews（1983）的比率产生较宽的分布，由于CR-s较大，确保了保守性。通常，测得的浓度分布较窄，可以在均匀底物上的一个小采样点上预期到。这里概述的通用方法是可行的，但是由于所考虑的站点的唯一性，在其他NORM情况下应谨慎使用。