REMdb as a framework for collaborations in environmental radioactivity research

Under the terms of Article 36 of the Euratom Treaty, European Union Member States (MSs) shall periodically communicate to the European Commission (EC) information on environmental radioactivity levels. These results have been introduced into the Radioactivity Environmental Monitoring database (REMdb) of the EC Joint Research Centre (JRC) sited in Ispra (Italy) (https://rem.jrc.ec.europa.eu/RemWeb/). The initial purpose of the REMdb was to bring together environmental radioactivity data produced in the aftermath of the Chernobyl accident, and to store them in a harmonised manner. Thus the database has two main objectives: 1) to collect the environmental radioactivity data gathered through the national environmental monitoring programs of the MSs to prepare comprehensive annual monitoring reports; and 2) to keep a historical record of the radiological accidents for scientific studies. Nowadays, containing nearly two million records of radioactivity levels in milk, water, air and mixed diet received from the MSs, the REMdb offers the scientific community dealing with environmental radioactivity endless research opportunities. The records stored in REMdb prior to 2007 are fully public, while the access to the data from the 2007-2015 period can be granted only after explicit request. This fact makes the REMdb a useful and unique pillar on which to perform environmental radioactivity studies at the European level, and which can be considered as a liaison platform between national and international scientific groups conducting collaborative research. Example of collaboration: Analysis of 7Be surface concentrations As a valuable proof of this use, the present work provides an overview of the research activity undertaken by a friendly scientific collaboration network created by the University of Belgrade, the University of Bologna and the REM group of the JRC in the study of the 7Be surface concentrations recorded across Europe. These sets of results represent one of the first attempts to better understand the 7Be distribution in Europe, as well as the impact of tropopause height (TPH) and other meteorological parameters exert on it.First, spatial and temporal distribution of the 7Be specific activity in surface air was carried out using the long-term database (1984–2011) of 34 sampling sites, focusing on describing the impact of the latitude and solar cycle on yearly and monthly concentrations (Hernández-Ceballos et al., 2015). Further, a cluster analysis was instead applied to identify spatial patterns in 7Be concentrations in Europe: results showed the presence of three distinguishable cluster groups (south, central and north of Europe) with clear differences between concentrations in both intensity and time trends, and with a latitudinal distribution of the sampling stations (Hernández-Ceballos et al., 2016a). These regions were also identified in an analysis of seasonal and spatial patterns of extremely high 7Be surface concentration (values above 95th percentile in each site) recorded over the 2001–2010 period across Europe (Ajtić et al., 2016a). This study reported that most of the extremes occur over the March–August period, while at least 10 % of the total number of extremes take place during autumn and winter. In Ajtić et al., 2016b these “cold extremes” were analysed in more detail, showing three meteorological scenarios associated with their occurrence in northern Europe. In these works, the impact of TPH on 7Be, and therefore, on the spatial distribution of 7Be in Europe, was also suggested. The influence of TPH on 7Be was further investigated in a separate study (Hernández-Ceballos et al., 2016b), which showed a larger TPH influence on 7Be during summer and a large spatial variability of TPH on 7Be levels with a clear gap between southern and northern Europe in the area of the polar front jet.