Methods, results and dose consequences of ¹⁰⁶Ru detection in the environment in Budapest, Hungary

From late September to early October of 2017, the majority of European networks involved in environmental radiological monitoring - including the environmental monitoring system of the KFKI Campus in Budapest - detected ¹⁰⁶Ru isotope of artificial origin in the atmosphere. The reported values higher than the minimum detectable activity (MDA) concentrations were in the range of 0.8 μBq/m³ - 145 mBq/m³. Based on the results of environmental measurements and the available meteorological data, assessments were made to analyze concentration levels of ¹⁰⁶Ru activity and to help understand the behavior of radioruthenium in various environmental media. Evaluation of the daily variation of activity levels indicated a maximum of 4 day-long residence time of ¹⁰⁶Ru contamination presence in ground level air in Budapest. An average ¹⁰⁶Ru activity concentration of 25.6 ± 1.4 mBq/m³ have been observed for the estimated residence time of ¹⁰⁶Ru in the air. Deposition of ¹⁰⁶Ru was dominantly influenced by rainfall, the major contributor wet deposition which led to an average of 11.3 ± 1.3 Bq/m² deposition on the ground surface prior to plume passage.