Groundwater Radon Precursor Anomalies Identification by EMD-LSTM Model

Groundwater radon concentrations can reflect the changes of crustal stress and strain. Scholars and scientific institutions have also recorded groundwater radon precursor anomalies before earthquakes. Therefore, groundwater radon monitoring is an effective means of predicting seismic activities. However, the variation of radon concentrations within groundwater is not only affected by structural factors, but also by environmental factors, such as air pressure, temperature, and rainfall. This causes difficulty in identifying the possible precursor anomalies. Therefore, the EMD-LSTM model is proposed to identify the radon anomalies. This study investigated the time series data of groundwater radon from well #32 located in Sichuan province. Three models (including the LSTM (Long Short-Term Memory) model with auxiliary data, the EMD-LSTM (Empirical Mode Decomposition Long Short-Term Memory) model with auxiliary data, and the EMD-LSTM model without auxiliary data) were developed in order to predict groundwater radon variations. The results indicated that the prediction accuracy of the EMD-LSTM model was much higher than that of the LSTM model, and the EMD-LSTM model without auxiliary data also can obtain an ideal prediction result. Furthermore, the different durations of seismic activities T (T = ±10, ±30, ±50, and ±100) were also investigated by comparing the identification results. The identification rate of the precursor anomalies was the highest when T = ±30. The EMD-LSTM model identified five possible radon anomalies among the seven selected earthquakes. Taking well #32 as an example, we provided a promising method, that was the EMD-LSTM model, to detect the groundwater radon anomalies. It also suggested that the EMD-LSTM model can be used to identify the possible precursor anomalies within future studies.

A Preliminary Study of Radon Equilibrium Factor at a Tourist Cave in Okinawa, Japan

The International Commission on Radiological Protection (ICRP) issued its Publication 137, Occupational Intakes of Radionuclides: Part 3 in which the radon equilibrium factor is fixed as 0.4 for tourist caves; however, several studies have reported a different value for the factor and its seasonal variation has also been observed. In this study, the radon concentration, equilibrium equivalent radon concentration and meteorological data were measured, and the equilibrium factor was evaluated in a tourist cave, Gyokusen-do Cave located in the southern part of Okinawa Island in southwestern Japan. Radon concentrations were measured with an AlphaGUARD and their corresponding meteorological data were measured with integrated sensors. Equilibrium equivalent radon concentration was measured with a continuous air monitor. The measured radon concentrations tended to be low in winter and high in summer, which is similar to previously obtained results. By contrast, the equilibrium factor tended to be high in winter (0.55 ± 0.09) and low in summer (0.24 ± 0.15), with a particularly large fluctuation in summer. It was concluded that measurements in different seasons are necessary for proper evaluation of radon equilibrium factor.

Dependence of concentration of radon on environmental parameters

Radon (222Ra) is a colourless and odourless natural radioactive element in gaseous state. The concentration of radon in the air is usually low, but it can be very high inside of a living space, because of its possibility to penetrate from a foundation soil over a basement into a building itself. People are daily exposed to a certain concentration of radon that is found in soil, water, air and food. This paper shows a correlation analysis of environmental parameters by using the model of multiple regressions. It defines certain statistical relations between environmental parameters such as temperature, humidity, and atmospheric pressure with measured values of radon concentrations. Measurements were carried out at several locations in various residential buildings in north-western Croatia. The results indicated that individual environmental parameters and radon concentration at individual locations were connected. For example, at one location the concentration of radon was decreasing if atmospheric pressure was increasing. Measurements at another location indicated that the concentration of radon was increasing if air humidity was increasing. Due to large number of different parameters affecting the concentration of radon in residential buildings, a satisfactory statistical model to predict the concentration of radon with environmental parameters is not easy to achieve since it was observed variability of radon concentrations with environmental parameters within different local sites. It is necessary to consider a longer period to determine with certainty a mathematical model that would give the most accurate prediction of radon concentration dependence on environmental parameters which can affect human health and quality of life.

Radon concentration measurement in water reservoirs for some areas of north Baghdad by RAD7

Radon is a naturally occurring, odorless, colorless, radioactive, tasteless, and noble gas. Radon concentrations have been measured by the usage of alpha spectroscopy (RAD-7). The RAD-7 measuring process is based on detecting alpha particles produced from the disintegration of radon and its products using a solid-state alpha detector (usually silicon), and then converting alpha radiation directly to an electrical signal. The radioactivity of radon gas was measured in forty-two samples from reservoir water for different areas north of Baghdad utilizing a RAD7 detector. This study proved that the high value of radon concentrations was less than the permissible limit as recorded by the World Health Organization.

Glass implanted 210 Po as a method of defining long-term retrospective exposure to radon: First experiments in Israel

In most epidemiological studies, contemporary radon measurements are used as a proxy for radon concentrations during the latency period even though extreme changes in radon levels may have occurred. Airborne radon decay products are deposited and implanted through alpha recoil into exposed glass surfaces, providing a measure of time-integrated retrospective radon concentration in the environment in which the glass has been located.

Distribution of Radon Concentrations in Active and Inactive Underground Mines: A Literature Review

Radon (Rn), a natural colorless, odorless, noble radioactive gas, with a half-life of 3.8 days, is an important source of natural ionizing radiation. It originates from the initial concentrations of uranium and its transmuted daughters in rocks, soil, and finally, waters and tends to be concentrated in closed spaces such as underground mines. The concentration of radon in mines contributes significantly to the increase in the dose of ionizing radiation received by humans visiting, accessing, working in these areas. The comparison of radon concentration in active and inactive mining sites, its effect on human health, and the different concentrations’ upper limits, applicable by state, are discussed in this paper.

The First Attempt to Reevaluate Radon and Thoron Exposure in Gansu Province Study Using Radon-Thoron Discriminating Measurement Technique

Although the epidemiological studies provide evidence for an increased risk of lung cancer risk associated with residential radon, an issue of radon-thoron discrimination remains to be solved. In this study, an updated evaluation of lung cancer risk among the residents in Gansu, China was performed where one of the major epidemiological studies on indoor radon demonstrated an increased risk of lung cancer. We analyzed data from a hospital-based case-control study that included 30 lung cancer cases and 39 controls with special attention to internal exposure assessment based on the discriminative measurement technique of radon isotopes. Results from the analyses showed non-significant increased lung cancer risks; odds ratios (ORs) adjusted for age, smoking, and total income were 0.35 (95% CI: 0.07–1.74) and 0.27 (95% CI: 0.04–1.74) for groups living in residences with indoor radon concentrations of 50–100 Bq m−3 and over 100 Bq m−3, respectively, compared with those with < 50 Bq m−3 indoor radon concentrations. Although the small sample size hampers the usefulness of present analyses, our study suggests that reevaluation of lung cancer risk associated with residential radon in the epidemiological studies will be required on the basis of precise exposure assessment.

Relationships among Indoor Radon, Earthquake Magnitude Data and Lung Cancer Risks in a Residential Building of an Apulian Town (Southern Italy)

(1) Background: The association of radon-222 with lung cancer is well studied. The aim of the study was to validate a model of indoor radon measurements, to apply radon software to estimate lung cancer cases that are attributable to radon and to study the relationship between radon and earthquakes. (2) Methods: Different data detectors were used to obtain radon measurements in different places. Continuous data collection and predictions of indoor radon concentrations were carried out. Software was used to assess radon-attributable lung cancer cases, and data related to earthquake magnitudes were downloaded from Italian Vulcanology Institute. (3) Results: As expected, the highest radon concentrations were observed on the ground floor (232 ± 232 Bq/m3), with higher values measured during winter than in other seasons. The comparison of the detectors showed the overlapping of the two detectors-measured data sets. The cases of lung cancer that were attributable to radon in Locorotondo were studied (3.66/10,000). From the multivariate analysis of the relationship between high radon concentrations and high earthquake magnitude values, they show statistically significant ORs of just over 1. (4) Conclusions: Although the measured values are, on average, within the reference level, prevention measures must be implemented, as the measured radon values allow us to estimate an expected value of 3.66 cases of lung cancer per 10,000 people in the resident population.

Control of the Health Risk of Radon Exposure in the Republic of Moldova

The paper presents the results of a national radon survey conducted in the context of the Republic of Moldova. The study included about 2500 homes of different types, located in urban and rural localities in different areas of the country. The RADTRAK2 detectors kindly provided by the RADONOVA laboratory, Uppsala, Sweden, for the MOL9007 project funded by the International Atomic Energy Agency (IAEA) have been used. The exposure period was 90 days. The measured radon concentrations are the following: the average (±standard deviation) 252.8 ± 215.9 Bq/m3; the range (minimum–maximum) 10–1480 Bq/m3; the median 200 Bq/m3 and the geometric mean (± geometric standard deviation) 158.5 ± 3.0 Bq/m3. The results of the study allowed mapping indoor radon and identifying localities with increased radon concentrations. In order to reduce the high radon concentrations in places recording >300 Bq/m3, appropriate measures have been proposed according to the legislation in force. The cluster analysis showed positive links between the radon concentration in dwellings and the incidence of respiratory diseases, especially the bronchopulmonary cancer in the country.