The main purpose of this paper is to analyse the activities for Radon Risk Communication under the National Radon Program and to outline the main objectives in the new Radon Action Plan for developing a communication strategy. The preliminary activities were implemented under the National Radon Program. Survey via the Internet for assessment of perceptions and the level of knowledge regarding radon was conducted as a benchmark for evaluation of public awareness. The main channels which were used to inform the population were publications on websites, magazines, in TV interviews and radio (local), seminars, from which the most widely used were local seminars. On the basis of this, six objectives are proposed for a new radon action plan: to obtain wide organisational support and to determine the need of risk communication; to develop goals for risk communication with key messages to different target groups; to form and to train the communication team; to evaluate the stakeholders and the communication channels; to develop plans with different organisations for different focus groups; to evaluate the radon risk communication programme.

ABSTRACT Chronic inflammation is a common denominator linking a wide range of health conditions, including tissue response to radiation exposure. This pilot study investigates whether inflammatory cytokines—interleukins IL-6, −8, −10, monocyte chemoattractant protein-1 (MCP-1) and tumor necrosis factor α (TNFα)—can be used as early biomarkers of radiation-induced adverse health effects in occupationally exposed individuals. The study included 33 workers externally exposed to gamma radiation from the nuclear industry with cumulated doses from 0.11 to 190 mSv and 42 non-exposed controls of comparable age and socio-economic status. IL-6, IL-8, MCP-1, TNFα and IL-10 were analyzed by enzyme-linked assay (ELISA) in blood plasma samples. Total antioxidant status (TAS) of blood plasma was determined by a colorimetric assay. The radiation-exposed and control groups measured significantly different levels of MCP-1, TNFα and IL-10. Seventy-five percent of radiation workers had either high MCP-1 levels or low IL-10 levels and 30% had all three cytokines dysregulated. Approximately 50% of workers showed upregulated antioxidant status, which appeared to compensate the pro-inflammatory cytokine shift in these individuals. In contrast, only 2% of the control subjects were found to have three dysregulated cytokines, and all of them measured within the normal TAS range. The present study may represent an important step towards the establishment of a reliable set of biomarkers for health-risk estimation in population cohorts exposed to low radiation doses.

A severe radiation accident occurred on Tuesday, 14 June 2011 in an industrial irradiation facility. Five people were exposed for 5-10 min to (60)Co source (137 TBq-3710 Ci). This accident was the first one in Bulgaria, in which the whole-body irradiation doses exceeded 1 Gy and suggested the development of acute radiation syndrome (ARS). This report discusses the diagnostic features of ARS and the use of the METREPOL concept and its diagnostic criteria in assessing the severity of radiation damage. The results used in this study show that injury assessment based only on prodromal symptoms is burdened with a serious error. The probable reasons are at least two: one is the unwillingness of victims to be diagnosed as involved in radiation emergency, which could reflect on their working status, and the other is the slight manifestation of symptoms due to the specific geometry of irradiation. The European Guideline for Medical Management of ARS is a good basis for an early diagnosis of radiation injury.

The purpose of this article is to analyze the results of a 10-year survey of the radiation effects of some immune parameters of occupationally exposed personnel from the Nuclear Power Plant “Kozloduy”, Bulgaria. 438 persons working in NPP with cumulative doses between 0.06 mSv and 766.36mSv and a control group with 65 persons were studied. Flow cytometry measurements of T, B, natural killer (NK) and natural killer T (NKT) cell lymphocyte populations were performed. Data were interpreted with regard to cumulative doses, length of service and age. The average values of the studied parameters of cellular immunity were in the reference range relative to age and for most of the workers were not significantly different from the control values. Low doses of ionizing radiation showed some trends of change in the number of CD3+CD4+ helper-inducer lymphocytes, CD3+ CD8+ and NKT cell counts. The observed changes in some of the studied parameters could be interpreted in terms of adaptation processes at low doses. At doses above 100–200 mSv, compensatory mechanisms might be involved to balance deviations in lymphocyte subsets. The observed variations in some cases could not be attributed only to the radiation exposure because of the impact of a number of other exogenous and endogenous factors on the immune system.

The aim of the present study is to assess the effects of low-dose occupational exposure on T helper response. One Hundred five employees working in Nuclear Power Plant, Kozloduy, Bulgaria and control group of 32 persons are included in this investigation. Flow cytometry measurements of T-cell populations and subpopulations and natural killer T cells are performed and levels of G, A, and M immunoglobulins and interleukin 2 (IL-2), IL-4, and interferon γ were determined. The data interpreted with regard to cumulative doses, length of service, and age. The results of the present study are not enough to outline a clear impact of occupational radiation exposure on T helper populations. Nevertheless, the observed even slight trends in some lymphocyte’s populations and in cytokines profile give us the reason to assume a possibility of a gradual polarization of T helper 1 to T helper 2 immune response at dose range 100 to 200 mSv. The results of the present study indicate the need to perform a more detailed epidemiological survey including potential confounding and misclassifying factors and possible selection bias that could influence the results.