Guillén J, Baeza A, Beresford N A, Wood M D
LARUEX, Dpt. Applied Physics, Faculty of Veterinary Sciences, University of Extremadura, Avda. Universidad, s/n, 10003, Cáceres, Spain.
LARUEX, Dpt. Applied Physics, Faculty of Veterinary Sciences, University of Extremadura, Avda. Universidad, s/n, 10003, Cáceres, Spain.
J Environ Radioact. 2017 Sep;175-176:70-77. doi: 10.1016/j.jenvrad.2017.04.014. Epub 2017 Apr 28.
Fungi are used as biomonitors of forest ecosystems, having comparatively high uptakes of anthropogenic and naturally occurring radionuclides. However, whilst they are known to accumulate radionuclides they are not typically considered in radiological assessment tools for environmental (non-human biota) assessment. In this paper the total dose rate to fungi is estimated using the ERICA Tool, assuming different fruiting body geometries, a single ellipsoid and more complex geometries considering the different components of the fruit body and their differing radionuclide contents based upon measurement data. Anthropogenic and naturally occurring radionuclide concentrations from the Mediterranean ecosystem (Spain) were used in this assessment. The total estimated weighted dose rate was in the range 0.31-3.4 μGy/h (5-95 percentile), similar to natural exposure rates reported for other wild groups. The total estimated dose was dominated by internal exposure, especially from Ra and Po. Differences in dose rate between complex geometries and a simple ellipsoid model were negligible. Therefore, the simple ellipsoid model is recommended to assess dose rates to fungal fruiting bodies. Fungal mycelium was also modelled assuming a long filament. Using these geometries, assessments for fungal fruiting bodies and mycelium under different scenarios (post-accident, planned release and existing exposure) were conducted, each being based on available monitoring data. The estimated total dose rate in each case was below the ERICA screening benchmark dose, except for the example post-accident existing exposure scenario (the Chernobyl Exclusion Zone) for which a dose rate in excess of 35 μGy/h was estimated for the fruiting body. Estimated mycelium dose rate in this post-accident existing exposure scenario was close to the 400 μGy/h benchmark for plants, although fungi are generally considered to be less radiosensitive than plants. Further research on appropriate mycelium geometries and their radionuclide content is required. Based on the assessments presented in this paper, there is no need to recommend that fungi should be added to the existing assessment tools and frameworks; if required some tools allow a geometry representing fungi to be created and used within a dose assessment.
真菌被用作森林生态系统的生物监测器，对人为和天然存在的放射性核素具有较高的吸收量。然而，尽管已知它们会积累放射性核素，但在环境（非人类生物群）评估的放射学评估工具中通常并未将其考虑在内。在本文中，使用ERICA工具估算了真菌的总剂量率，假设了不同的子实体几何形状，一个单一的椭球体以及更复杂的几何形状，后者考虑了子实体的不同组成部分及其基于测量数据的不同放射性核素含量。本次评估使用了来自地中海生态系统（西班牙）的人为和天然存在的放射性核素浓度。估计的总加权剂量率范围为0.31 - 3.4 μGy/h（第5 - 95百分位数），与其他野生群体报告的自然暴露率相似。估计的总剂量以内照射为主，尤其是来自镭和钋的内照射。复杂几何形状和简单椭球体模型之间的剂量率差异可忽略不计。因此，建议使用简单椭球体模型来评估真菌子实体的剂量率。还假设真菌菌丝体为长丝进行了建模。使用这些几何形状，针对不同情景（事故后、计划释放和现有暴露）下的真菌子实体和菌丝体进行了评估，每种情景均基于可用的监测数据。除了事故后现有暴露情景的示例（切尔诺贝利禁区）外，每种情况下估计的总剂量率均低于ERICA筛选基准剂量，在该示例中，估计子实体的剂量率超过了35 μGy/h。在这种事故后现有暴露情景中，估计的菌丝体剂量率接近植物的400 μGy/h基准，尽管真菌通常被认为比植物对辐射的敏感性更低。需要对合适的菌丝体几何形状及其放射性核素含量进行进一步研究。基于本文所呈现的评估结果，无需建议将真菌添加到现有的评估工具和框架中；如果需要，一些工具允许创建并在剂量评估中使用代表真菌的几何形状。
