Radon

Radon exposure risks among residents proximal to gold mine tailings in Gauteng Province, South Africa: a cross-sectional preliminary study protocol

Gold mine tailings, a legacy of the mining industry, harbors significant amount of radon gas, a classified human carcinogen. Radon exposure, especially near tailings, is a significant public health threat, potentially leading to increased risk of lung cancer, leukemia, and chronic obstructive pulmonary disease (COPD). These health problems are often associated with lower survival rates and significant financial burdens. This ongoing research aim to evaluating the relationship between indoor radon exposure and lung cancer, leukemia, and COPD risks among residents proximal to gold mine tailings in Gauteng Province, South Africa. This cross-sectional preliminary study focus on two distinct groups: Riverlea (exposed group, <2 km to Gold mine tailings) and Orlando East (unexposed group, >2 km to Gold mine tailings). Indoor radon levels is measured using AlphaE monitors, while health risks (lung cancer, leukemia, and COPD) linked to exposure are evaluated through interview-administered questionnaire and secondary data from Gauteng Health Department. Of the 476 residents randomly selected for this study, 300 have already participated, with balanced representation from both the exposed and unexposed groups. The study will compare indoor radon levels and health outcomes between the two groups. This study's results could aid in creating targeted interventions and policies to mitigate indoor radon exposure risks and safeguard vulnerable communities from this significant public health hazard.

Assessing the Impact of Housing Features and Environmental Factors on Home Indoor Radon Concentration Levels on the Navajo Nation

Uranium is naturally found in the environment as a radioactive metal element with high concentrations in the Southwestern US. In this region is the Navajo Nation, which spans approximately 69,930 square kilometers. A decay product of uranium is radon gas, a lung carcinogen that has no color, odor, or taste. Radon gas may pass from soil into homes; and, indoor accumulation has been associated with geographical location, seasonality, home construction materials, and home ventilation. A home and indoor radon survey was conducted from November 2014 through May 2015, with volunteers who reported residence on the Navajo Nation. Home geolocation, structural characteristics, temperature (°C) during radon testing, and elevation (meters) were recorded. Short-term indoor radon kits were used to measure indoor radon levels. 51 homes were measured for indoor radon levels, with an arithmetic mean concentration of 60.5 Becquerels per cubic meter (Bq/m³) (SD = 42.7). The mean indoor radon concentrations (Bq/m³) by house type were: mobile, 29.0 (SD = 22.9); wood, 58.6 (SD = 36.0); hogan, 74.0 (SD = 0.0); homes constructed of cement and wood, 82.6 (SD = 3.5); and homes constructed of concrete and cement, 105.7 (SD = 55.8). A key observation is that house construction type appears to be associated with the mean home indoor radon concentration. This observation has been published in that the basic structural make-up of the home may affect home ventilation and therefore indoor radon concentration levels.

MEASUREMENTS IN AFGHANISTAN USING AN ACTIVE RADON EXPOSURE METER AND ASSESSMENT OF RELATED ANNUAL EFFECTIVE DOSE

Radon gas concentrations in eight basements, four living rooms and four caves from different locations in Kabul and Panjsher, Afghanistan, were measured by using eight active radon exposure meters recently developed by the Helmholtz Center in Munich, Germany. The two-phase measurements lasted from a week to a year. In the first phase of measurements which lasted one week, the mean activity concentrations ranged from 6 to 120 Bq/m3 and 25 to 139 Bq/m3 for the basements and caves, respectively. In the second phase of measurements which lasted one year, the mean activity concentrations ranged from 33 to 2064 Bq/m3 and the corresponding effective annual doses calculated for the inhabitants were in the range between 0.6 and 33.4 mSv. As some of the values are rather high and exceed the recommended recommendations by IAEA and ICRP, based on the local conditions a number of simple recommendations has been proposed for the possible reduction of effective annual dose caused by radon in the measurement locations.

Time-to-Progression of NSCLC from Early to Advanced Stages: An Analysis of data from SEER Registry and a Single Institute

The average time required for cancers to progress through stages can be reflected in the average age of the patients diagnosed at each stage of disease. To estimate the time it takes for non-small-cell lung cancer (NSCLC) to progress through different tumor, node and metastasis (TNM) stages and sizes, we compared the mean adjusted age of 45904 NSCLC patients with different stages and tumor sizes from Surveillance, Epidemiology and End Results (SEER) cancer registry database and our institute. Multiple-linear-regression models for age were generated adjusting for various factors. Caucasian, African-American and Asian patients with stage IA cancers were on average 0.8, 1.0 and 1.38 adjusted years younger, respectively, than those with stage IIIB cancers (p < 0.001). And these with T1a cancers were on average 0.84, 0.92 and 1.21 adjusted years younger, respectively, than patients with T3 cancers (p < 0.001). Patients with tumors measuring larger than 8 cm in diameter were on average 0.85 adjusted years older than these with tumors smaller than 1 cm (p < 0.001), with Caucasian demonstrating the shortest age span (0.79 years, P < 0.001). In conclusion, the time-to-progression of NSCLC from early to advanced stages varied among ethnicities, Caucasian patients demonstrating a more rapid progression nature of tumor than their African-American and Asian counterparts.

African American health disparities in lung cancer

Lung cancer is a leading cause of cancer-related deaths in the United States and globally. African Americans experience significant differences in lung cancer incidence and mortality. Smoking is the single greatest risk for lung cancer, making smoking cessation programs a potentially fruitful approach for reducing the risk of lung cancer. Despite clinical practice guidelines that prompt nurses to advise patients to quit smoking, only a small percentage of nurses do so. Minority patients are less likely than Whites to receive smoking cessation advice. This article discusses recent findings on the pathophysiology and risks for lung cancer. The literature on smoking cessation research is examined to determine the features of successful cessation interventions. Recommendations are offered for enhancing tobacco cessation efforts in nursing practice, education, and research.

Racial and regional disparities in lung cancer incidence

BACKGROUND

Lung cancer is the second most commonly diagnosed cancer and the leading cause of cancer-related death in the United States (US). We examined data from 2004 to 2006 for lung cancer incidence rates by demographics, including race and geographic region, to identify potential health disparities.

METHODS

Data from cancer registries affiliated with the Centers for Disease Control and Prevention's (CDC) National Program of Cancer Registries (NPCR), and the National Cancer Institute's (NCI) Surveillance, Epidemiology, and End Results Program (SEER) were used for this study; representing 100% of the US population. Age-adjusted incidence rates and 95% confidence intervals for demographic (age, sex, race, ethnicity, and US Census region), and tumor (stage, grade, and histology) characteristics were calculated.

RESULTS

During 2004 to 2006, 623,388 people (overall rate of 68.9 per 100,000) were diagnosed with lung cancer in the US. Lung cancer incidence rates were highest among men (86.2), Blacks (73.0), persons aged 70 to 79 years (431.1), and those living in the South (74.7). Among Whites, the highest lung cancer incidence rate was in the South (75.6); the highest rates among Blacks (88.9) and American Indians/Alaska Natives (65.4) in the Midwest, Asians/Pacific Islanders in the West (40.0), and Hispanics in the Northeast (40.3).

CONCLUSIONS

Our findings of racial, ethnic, and regional disparities in lung cancer incidence suggest a need for the development and implementation of more effective culturally specific preventive and treatment strategies that will ultimately reduce the disproportionate burden of lung cancer in the US.

Oxidative damage in various tissues of rats exposed to radon

Oxidative damage can be induced by many environmental stressors. 8-Hydroxydeoxyguanosine (8-OHdG) has been used as a biomarker of oxidative DNA damage in both in vitro and in vivo studies. In the present study, Wistar rats were exposed to radon gas at a concentration of 100,000Bq/m(3) for 12 h/d for 30, 60, and 120 d, equivalent to cumulative doses of 60, 120, and 240 working level months (WLM), respectively. Changes in levels of 8-OHdG, reactive oxygen species (ROS), and total antioxidant (T-AOC), as well as expressions of some DNA repair enzymes such as 8-oxoguanine DNA glycosylase (OGG1) and MutT homolog 1 (oxidized purine nucleoside triphosphatase, MTH1), were determined in rat urine, peripheral blood lymphocytes, and lung after exposure to radon. The results revealed an increase in 8-OHdG and ROS levels, a decrease in T-AOC levels, and reduced OGG1 and MTH1 expression levels. The elevated amount of 8-OHdG in urine or lymphocytes was positively correlated with the cumulative exposure dose, whereas OGG1 and MHT1 expression levels in lung were inversely correlated with cumulative exposure dose. These findings indicate that oxidative damage induced by radon may be involved in radon-induced carcinogenesis.

Biological effects of alpha particle radiation exposure on human monocytic cells

Radon ((222)Rn) gas produces decay progeny that emits high energy alpha (α)-particles. Epidemiological studies have shown that exposure to (222)Rn is linked with elevated risk of developing lung cancer, however clear mechanisms leading to such effects have not been delineated. Cytokines play a critical role in inflammation and their dysregulated production often contributes to disease pathogenesis. In this study, Bio-plex multiplex technology was employed to investigate modulations of 27 pro-inflammatory cytokines following exposure of human monocytic cells to 1.5 Gy of α-particle radiation. Concurrently, DNA damage was assessed by examining the formation of phosphorylated H2A histone family X (γ-H2AX) sites. Of the 27 cytokines assessed, 4 cytokines were shown to be statistically downregulated by ∼2 fold relative to the untreated controls and included the interleukin (IL) family of proteins (IL-2, IL-15 and IL-17) and macrophage inflammatory protein 1 beta (MIP-1b). Interferon-inducible protein-12 (IP-12), vascular endothelial growth factor and regulated on activation normal T cell expressed and secreted (RANTES) were shown to be high expressors and upregulated. Cells irradiated with α-particles ranging from 0.27 to 2.14 Gy showed statistically significant, dose-dependant increases in γ-H2AX formation. These data suggest that α-particle radiation causes dysregulation in the production of a number of pro-inflammatory cytokines and results in significant DNA damage.

Modeling a 222Rn measurement technique based on absorption in polycarbonates and track-etch counting

In the last decade the high radon absorption ability of some polycarbonates has been successfully used to measure Rn in air, water, and soil-gas. This report describes a theoretical model of the response of Rn detectors that are based on radon absorption and electrochemical etching of alpha-tracks in polycarbonates. The model is based on the volume distribution of the absorbed Rn and the response function of electrochemically etched Makrofol. Theoretical expression for the calibration factor is obtained, and comparison with experimental results is made. The comparison demonstrates very good correspondence between theoretical and experimental values. The conclusion is that this model can be useful in design and optimization of Rn measurements based on absorption in polycarbonates.

Cytogenetic damage in human blood lymphocytes exposed in vitro to radon

The effect of radon in inducing DNA damage was investigated in vitro by two well-established cytogenetic assays. Blood samples were irradiated with radon using a novel irradiation assembly. Doses varied between 0 and 127 mGy for chromosome aberration (CA) assay and 0 and 120 mGy for cytokinesis blocked micronucleus (CBMN) assay. Dose-rates varied between 0.000054 and 0.708 mGy/min. After the irradiation period of 3h, excess radon gas was released and cultures were initiated using standard procedures. Chromosome aberrations such as dicentrics, excess acentric fragments, acentric rings, centric rings, chromatid breaks were observed. Micronuclei, nucleoplasmic bridges and nuclear buds were scored by the CBMN assay. A significant increase in the frequency of dicentrics, excess acentric fragments and centric rings was observed with increasing radon dose, whereas total acentric rings plus double minute and chromatid breaks/cell were not significantly elevated. In CBMN assay, the frequency of micronuclei was found to be significantly raised whereas that of nucleoplasmic bridges and nuclear buds were not. Nucleoplasmic bridges and nuclear buds tended to increase with dose but did not achieve statistical significance. There was a strong positive correlation between nucleoplasmic bridges and dicentrics (P<0.028) or rings (P<0.0001) and between micronuclei and acentric fragments (P<0.0005). The study shows that radon is capable of inducing significant chromosome damage at very low doses and dose-rates.

Lung cancer incidence among American Indians and Alaska Natives in the United States, 1999-2004

BACKGROUND

Lung cancer incidence rates among American Indians and Alaska Natives (AI/ANs) in the United States have not been described well, primarily because of race misclassification and, until the 1990s, incomplete coverage of their population by cancer registries. Smoking, the predominant cause of lung cancer, is particularly prevalent among this population.

METHODS

Data from the National Program of Cancer Registries and the Surveillance, Epidemiology, and End Results Program were combined to estimate age-adjusted incidence rates of lung cancer during 1999 through 2004. Cases were linked to Indian Health Service (IHS) registration databases to identify AI/ANs whose race may have been misclassified. Age-adjusted rates were calculated for Contract Health Service Delivery Area (CHSDA) counties and for all counties by IHS region, and comparisons were made between AI/ANs and non-Hispanic whites (NHWs).

RESULTS

Among populations living in CHSDA counties, NHWs overall had higher rates of lung cancer than AI/ANs. However, the rates (per 100,000 population) among AI/ANs varied substantially between IHS regions from 14.9 (Southwest) to 87.1 (Southern Plains), 93.2 (Alaska), and 104.3 (Northern Plains). Approximately 41.6% of AI/AN lung cancer cases were diagnosed before age 65 years compared with approximately 29.8% of NHW lung cancer cases. The overall percentage stage distribution was not different between AI/ANs and NHWs. Squamous cell carcinomas were slightly more common and adenocarcinomas were less common among AI/ANs than among NHWs. Lung cancer rates were not decreasing for AI/ANs as they were for NHWs.

CONCLUSIONS

Data from this study clarified the need for culturally appropriate tobacco prevention and control policies and resources for AI/ANs in all regions, and especially in the Plains and Alaska.

Radon-induced proteomic profile of lung tissue in rats

The aim of this study was to investigate the differential expression of proteins in lung of rats following long-term exposure to radon. The total proteins of lung tissue from Wistar rats exposed to radon for cumulative doses up to 100, 200, or 400 WLM (working level months) were isolated by two-dimensional electrophoresis (2-DE) and analyzed with ImageMaster 2D Platinum software. Comparison of the 2-DE images between the control and radon-exposed groups resulted in 14 upregulated and 9 downregulated protein spots, of which 15 were identified by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) or matrix-assisted laser desorption/ionization time-of-flight/time-of-flight mass spectrometry (MALDI-TOF/TOF-MS). The simultaneous up-expressions of RAGE and S100A6 indicated that both proteins might be applied as biomarkers for lung injury induced by long-term radon exposure.

Rural parents' perceptions of risks associated with their children's exposure to radon

OBJECTIVES

To examine the level of awareness of radon issues, correlates of elective testing behaviors, and the accuracy of risk perception for radon exposures among rural residents receiving public health services.

DESIGN

A cross-sectional design was used in which questionnaire data and household analytic data for radon levels were collected from a nonprobabilistic sample of rural households.

SAMPLE

Thirty-one rural households with 71 adults and 60 children participated in the study. Primary household respondents were female (100%), Caucasian (97%), and primarily (94%) between 21 and 40 years of age.

MEASUREMENT

Questionnaire data consisted of knowledge and risk perception items about radon and all homes were tested for the presence of radon.

RESULTS

The prevalence of high airborne radon (defined as> or=4 pCi/l) was 32%. More than a third of the sample underestimated the seriousness of health effects of radon exposure, 39% disagreed that being around less radon would improve the long-term health of their children, and 52% were unsure whether radon could cause health problems. After adjusting for chance, only 21% of the subjects correctly understood their risk status.

CONCLUSIONS

This study provides preliminary evidence that low-income rural citizens do not understand their risk of radon exposure or the deleterious consequences of exposure.

High radon concentrations in a house near Castleisland, County Kerry (Ireland)--identification, remediation and post-remediation

In July 2003, a passive radon measurement carried out over a 3-month period in a house near Castleisland in County Kerry (South-West of Ireland) identified a seasonally adjusted annual average concentration of approximately 49 000 Bq m(-3). This is the highest radon concentration ever recorded in a house in Ireland. It is almost 250 times higher than the national reference level of 200 Bq m(-3) for homes and it gives rise to an estimated annual radiation dose of approximately 1.2 Sv to the occupants. This paper describes the identification of the 'Castleisland house' and gives information on the local geology, the levels of natural background radiation in the area and the follow-up actions taken to remediate the house as well as the efforts made to heighten awareness in the locality of the hazards from radon.