Be-7 measurement in an urban area using a low-resolution gamma spectrometer

Be-7 is a cosmogenic radioactive isotope formed by spallation of cosmic rays in the atmosphere. Despite its relevance in environmental studies, its distribution in urban soils and sediments remains poorly characterized. This study addresses this gap by measuring Be-7 concentrations in soil and sediment samples from an urban area under three distinct scenarios: a natural slope, a rainwater drainage ditch, and sediment accumulated along asphalt curbs. Gamma spectrometry was performed using a thallium-activated sodium iodide (NaI(Tl)) detector, without the need for chemical separation. Soil samples from the slope and drainage ditch exhibited Be-7 activities ranging from below the detection limit (5Bq/kg) to 39±5Bq/kg. In contrast, sediment samples from paved areas showed significantly higher activities, reaching up to 873±5Bq/kg. These elevated concentrations are likely due to surface runoff during rainfall events, which mobilizes and deposits Be-7 in roadside sediments.