Assessing radiation risk perception by means of a European stakeholder survey.

It is increasingly recognised that stakeholder views can be essential for ascertaining the credibility of those entrusted with protection of the public and workers against radiation risks, the robustness of the approaches to protection and the relevance of research underpinning radiation protection (RP). The CONCERT European Joint Programme of RP research included consideration of stakeholder views. These were evaluated by means of a publicly available survey, translated into 15 languages, to encourage responses from a wide range of European countries. The survey ran in 2017 and received some 1961 responses from many countries, although response rates varied widely between countries. The survey respondents were largely highly educated, with many having a professional connection to RP or the use of radiation in medicine or industry. Survey results indicated a high level of scientific/technical knowledge relevant to RP and indicated a general trust of most actors involved in the RP field, perhaps unsurprisingly given the nature of the sampled population. Most expressed a reasonable level of satisfaction with the information available to them on radiation risk, but there is clearly room for improvement. Additionally, the survey identified potential training needs amongst the groups who responded. It is concluded that, while the survey results are limited by the non-representativeness of the respondents by comparison with the population of the European Union as a whole, it has been successful in gaining insights into areas where communication could be improved, where professional training gaps are present and where research could help to build wider trust in RP.

Long-term monitoring of a water treatment technology designed for radium removal - removal efficiencies and NORM formation.

A drinking water treatment plant in Viimsi, Estonia was monitored over three years for iron, manganese, radium-226, radium-228, and their daughter nuclides in order to determine the efficiency of the treatment process, get an insight of the removal mechanisms and interactions between radium, iron, and manganese, and assess the overall longevity and performance of the technology and possible build-up of NORM from the treatment process. During the study, samples were collected from raw water, first and second stage filtrate, consumer water, backwash water, and filter materials. The results show a consistent removal efficiency for iron and manganese, as well as an average of over 85% removal for radium with a slight decline with time. Backwash process has been optimized for maximum radium removal from the filters, while keeping the radium concentrations in the backwash water below exemption levels. However, accumulation of radium and thorium occurs in the filter material, exceeding exemption levels in the top layer of the filter columns in less than a year. By the end of the observation period, activity concentrations in the top layer of the columns were above 30 000 Bq/kg for Ra-226 and Ra-228, and around 15 000 Bq/kg for Th-228. Radionuclides are not homogenously distributed in the filter columns. In order to estimate the average activity concentrations in the filter media, the height distribution of radionuclides has to be accounted for. Two years and two months after commissioning of the treatment plant average activity concentrations of Ra isotopes in the filter columns were in a range of 10 000 Bq/kg while Th-228 activity concentration was roughly 3500 Bq/kg.

Long-term monitoring of water treatment technology designed for radium removal-removal efficiencies and NORM formation.

A drinking water treatment plant in Viimsi, Estonia, was monitored over three years for iron, manganese, radium-226, radium-228, as well as their daughter nuclides, in order to determine the efficiency of the treatment process, gain an insight into the removal mechanisms and interactions between radium, iron, and manganese, and assess the overall longevity and performance of the technology along with the possible build-up of NORM in the treatment process. During the study, samples were collected from raw water, first and second stage filtrate, consumer water, backwash water and filter materials. The results show consistent removal efficiency for iron and manganese, as well as an average of over 85% removal for radium with a slight decline over time. The backwash process has been optimised for maximum radium removal from the filters, while keeping concentrations in the backwash water below exemption levels. However, the accumulation of radium and thorium occurs in the filter material, exceeding exemption levels in the top layer of the filter columns in less than a year. By the end of the observation period, activity concentrations in the top layer of the columns were above 30 000 Bq kg-1 for Ra-226 and Ra-228, and around 15 000 Bq kg-1 for Th-228. Radionuclides are not homogenously distributed in the filter columns. In order to estimate the average activity concentrations in the filter media, the height distribution of radionuclides has to be accounted for. Two years and two months after commissioning the treatment plant, the average activity concentrations of Ra isotopes in the filter columns were in the range 10 000 Bq kg-1, while Th-228 activity concentration was roughly 3500 Bq kg-1.

Temporal changes in radiological and chemical composition of Cambrian-Vendian groundwater in conditions of intensive water consumption.

Intensive groundwater uptake is a process at the intersection of the anthroposphere, hydrosphere, and lithosphere. In this study, groundwater uptake on a peninsula where only one aquifer system - the Cambrian-Vendian (CmV) - is available for drinking water uptake is observed for a period of four years for relevant radionuclides and chemical parameters (Cl, Mn, Fe, δ18O). Intensive groundwater uptake from the CmV aquifer system may lead to water inflow either from the sea, through ancient buried valleys or from the under-laying crystalline basement rock which is rich in natural radionuclides. Changes in the geochemical conditions in the aquifer may in turn bring about desorption of Ra from sediment surface. Knowing the hydrogeological background of the wells helps to predict possible changes in water quality which in turn are important for sustainable groundwater management and optimization of water treatment processes. Changes in Cl and Ra concentrations are critical parameters to monitor for sustainable management of the CmV groundwater. Radionuclide activity concentrations in groundwater are often considered rather stable, minimum monitoring frequency of the total indicative dose from drinking water is set at once every ten years. The present study demonstrates that this is not sufficient for ensuring stable drinking water quality in case of aquifer systems as sensitive as the CmV aquifer system. Changes in Cl concentrations can be used as a tool to predict Ra activity concentrations and distribute the production between different wells opening to the same aquifer system.

Groundwater treatment as a source of indoor radon.

New Viimsi Parish water treatment plant (Northern Estonia) was investigated in order to determine whether the open filter columns serve as a source of (222)Rn generation in the treatment process and whether they influence indoor air (222)Rn activity concentrations. (222)Rn measurements of indoor (222)Rn were performed at different locations of the treatment plant; water samples from incoming raw water, from all the purification stages, consumers water and solid filter material from two filtration stages were analyzed.