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In China, according to statistics about underground non-uranium mine radon levels, 15% exceed the national standard intervention level of 1000 Bq/m 3 , and some mines may exceed 10,000 Bq/m 3 . The relationship between radon exposure in underground miners and lung cancer has already been established, but the mechanisms and biological processes underlying it are poorly understood. In order to identify the genome-wide DNA methylation profile associated with long-term radon exposure, we performed the Infinium Human Methylation 850 K BeadChip measurement in whole blood samples obtained from 15 underground non-uranium miners and 10 matched aboveground control workers. Radon concentrations in the air of workplaces and living environments were measured by CR-39 radon detectors, and annual effective doses were calculated using the detection data. Under the high radon concentration with an average value of 12,700 Bq·m -3 , a total of 165 significant differentially methylated positions (127 hypermethylated sites and 38 hypomethylated sites) annotated to 71 genes were identified in underground miners (|Δβ| ≥ 0.10, p < 0.05), and the average DNA methylation level of 165 DMPs was significantly higher than that of the control workers. Most DMPs were found on chromosome 1, and approximately one-quarter of them were located in genomic promoter regions. Through bioinformatics analysis and pyrosequencing validation, five candidate genes differentially methylated by radon, including TIMP2, EMP2, CPT1B, AMD1 and SLC43A2 were identified. GO and KEGG analysis implicated that long term radon exposure could induce the lung cancer related biological processes such as cell adhesion and cellular polarity maintenance. Our study provides evidence for the alterations of genome-wide DNA methylation profiles induced by long-term high level radon exposure, and new insights into searching for carcinogenic biomarkers of high radon exposure in future studies., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Radiation exposure due to radon contributes most of the ionizing radiation exposure to people among natural radiation sources. This research measured the 222 Rn, 220 Rn by the RADUET and their progeny concentrations by the improved deposition based 222 Rn and 220 Rn progeny monitor, and the contribution of outdoor PM 2.5 concentrations to indoors by a modified steady-state mass balance model in Beijing, Changchun, China and Aomori, Japan. Based on these results, we preliminarily explored the relevance between the city level outdoor PM 2.5 exposure and indoor 222 Rn, 220 Rn inhalation exposure in these three metropolises with different air quality levels. The average equilibrium equivalent radon concentration (EERC) and equilibirum equivalent thoron concentration (EETC) indoor were 17.2 and 1.1 Bq m -3 in Beijing, 19.4 and 1.3 Bq m -3 in Changchun, and 10.8 and 0.9 Bq m -3 in Aomori, respectively. The indoor EERC and EETC in Beijing showed 1.4 and 2.2 times as high as that measured in 2006. The indoor radiation dose due to inhalation presented in a descending order as Changchun, Beijing and Aomori, which were in accordance with their outdoor 222 Rn concentrations. The indoor radiation doses due to 220 Rn contributed 30% of the total dose in the three cities, indicating that 220 Rn cannot be neglected when evaluating indoor radiation dose. It should be noted that, the indoor PM 2.5 concentrations of outdoor origin presented strong correlation (r = 0.772) with indoor EETC and moderate correlation (r = 0.663) with indoor EERC, indicating that the PM 2.5 of outdoor origin can break the concentration balance of the indoor PM 2.5 , then affect the indoor 222 Rn and 220 Rn behaviors, and further affect the inhalation exposure of radon., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

222Rn concentrations in underground drinking water samples in 12 cities from seven provinces (municipalities), China were determined by using a continuous radon monitor with air-water exchanger. A total of 73 underground water samples were collected. The observed radon levels were in a range of 1.0-63.8 Bq l-1, with a mean of 11.8 Bq l-1. The annual effective dose from inhalation of water-borne radon for average radon content in underground water was 72.6 μSv and for maximal observed radon concentration in underground water the corresponding dose was 393.8 μSv. The dose contribution of inhalation dose from water-borne radon should be paid attention in some granitic area.

Intercomparisons play an important role in maintaining a reasonable and accurate standard of measurement and quality. Integrating the radon-thoron detector of the National Institute for Radiological Protection (NIRP), China has continuously been a subject of four rounds of international intercomparisons organised by the National Institute of Radiological Sciences (NIRS), Japan during 2007-12. The intercomparisons were held at NIRS. The exercises included different exposures for both radon and thoron. The results of the intercomparison for the detectors of NIRP for both radon and thoron exposures were in the range of ±20% from the reference value and were categorised as 'Category I' in the intercomparison carried out in 2011. The radon and thoron results of the LD-P detector in four rounds of intercomparison exercises were summarised, and uncertainties of all the radon and thoron results of NIRP were within the acceptable range of 30% in environment. Radon and thoron measurement results between NIRP and NIRS were basically in agreement., (© The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Background: A causal relationship between occupational radon exposure in underground miners and lung cancer risk has been demonstrated through large cohort epidemiological studies. However, the mechanisms by which radon exposure causes adverse effects on lung tissue remain unclear. Epigenetic alterations such as DNA methylation may provide new insights into interactions at molecular levels induced by prolonged radon exposure. Methods: We used the Illumina Infinium Human Methylation 850 K BeadChip to detect and compare genome-wide DNA methylation profiles in peripheral blood samples from underground miners (n = 14) and aboveground workers (n = 9). Results: The average concentration of radon in underground workplaces was significantly higher than that of aboveground places (1,198 Bq·m−3 vs 58 Bq·m−3, p < 0.001). A total of 191 differentially methylated positions (DMPs) corresponding to 104 hub genes were identified when |Δβ| ≥ 0.1 and p < 0.05, with 107 hypermethylated sites and 84 hypomethylated sites. GO and KEGG analysis revealed that differentially methylated genes between underground miners and aboveground workers were prominently enriched in pathways/networks involved in neurotransmitter regulation, immunomodulatory effects and cell adhesion ability. Furthermore, methylation changes of selected genes FERMT1, ALCAM, HLA-DPA1, PON1 and OR2L13 were validated by pyrosequencing, which may play vital roles in these biological processes induced by radon. Conclusion: In summary, the DNA methylation pattern of the underground miners exposed to radon was distinct from that of the aboveground workers. Such abnormalities in the genomic DNA methylation profile associated with prolonged radon exposure are worth studying in terms of neuro- and immune-system regulation, as well as cell adhesion ability in the future. [ABSTRACT FROM AUTHOR]