Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523-1618, USA.
Centre for Environmental Radioactivity, Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, N-1433 Ås, Norway; Institute of Environmental Radioactivity, 1 Kanayagawa, Fukushima City, Fukushima 960-1296, Japan.
Environ Int. 2021 Oct;155:106675. doi: 10.1016/j.envint.2021.106675. Epub 2021 Jun 10.
The health effects associated with chronic low-dose, low-dose rate (LD-LDR) exposures to environmental radiation are uncertain. All dose-effect studies conducted outside controlled laboratory conditions are challenged by inherent complexities of ecological systems and difficulties quantifying dose to free-ranging organisms in natural environments. Consequently, the effects of chronic LD-LDR radiation exposures on wildlife health remain poorly understood and much debated. Here, samples from wild boar (Sus scrofa leucomystax) and rat snakes (Elaphe spp.) were collected between 2016 and 2018 across a gradient of radiation exposures in Fukushima, Japan. In vivo biomarkers of DNA damage and stress were evaluated as a function of multiple measurements of radiation dose. Specifically, we assessed frequencies of dicentric chromosomes (Telomere-Centromere Fluorescence in situ Hybridization: TC-FISH), telomere length (Telo-FISH, qPCR), and cortisol hormone levels (Enzyme Immunoassay: EIA) in wild boar, and telomere length (qPCR) in snakes. These biological parameters were then correlated to robust calculations of radiation dose rate at the time of capture and plausible upper bound lifetime dose, both of which incorporated internal and external dose. No significant relationships were observed between dicentric chromosome frequencies or telomere length and dose rate at capture or lifetime dose (p value range: 0.20-0.97). Radiation exposure significantly associated only with cortisol, where lower concentrations were associated with higher dose rates (r = 0.58; p < 0.0001), a relationship that was likely due to other (unmeasured) factors. Our results suggest that wild boar and snakes chronically exposed to LD-LDR radiation sufficient to prohibit human occupancy were not experiencing significant adverse health effects as assessed by biomarkers of DNA damage and stress.
慢性低剂量、低剂量率（LD-LDR）环境辐射暴露与健康影响尚不确定。在非受控实验室条件下进行的所有剂量效应研究都受到生态系统固有复杂性和难以量化自然环境中自由生活生物剂量的挑战。因此，慢性 LD-LDR 辐射暴露对野生动物健康的影响仍知之甚少，且存在广泛争议。在这里，2016 年至 2018 年期间在日本福岛县，采集了野猪（Sus scrofa leucomystax）和蛇类（Elaphe spp.）的样本，这些样本采集于辐射暴露梯度范围内。作为辐射剂量多种测量的函数，评估了体内生物标志物（DNA 损伤和应激）。具体而言，我们评估了野猪的双着丝粒染色体（端粒-着丝粒荧光原位杂交：TC-FISH）、端粒长度（Telo-FISH，qPCR）和皮质醇激素水平（酶免疫测定：EIA）的频率，以及蛇的端粒长度（qPCR）。然后，将这些生物学参数与捕获时的辐射剂量率的稳健计算以及可能的终生剂量上限相关联，这两个计算都包含了内部和外部剂量。在捕获时的剂量率或终生剂量与双着丝粒染色体频率或端粒长度之间未观察到显著关系（p 值范围：0.20-0.97）。仅与皮质醇相关的辐射暴露具有显著意义，其中较低的浓度与较高的剂量率相关（r=0.58；p<0.0001），这种关系可能归因于其他（未测量）因素。我们的研究结果表明，野猪和蛇类长期暴露于足以禁止人类居住的 LD-LDR 辐射下，并未出现由 DNA 损伤和应激生物标志物评估的明显不良健康影响。
