Seasonality of the 7Be specific activity in grasses and identification of potential sources using air mass back-trajectory analysis in Kenitra, Morocco
摘要
In this study, we investigate the seasonal variations and potential sources of beryllium-7 (7Be) measured in grasses at the Kenitra site, Morocco, over a seven-year period (2017–2023). During this period, 7Be concentrations, measured by gamma-ray spectrometry, varied from 11 ± 3 to 670 ± 60 Bq kg−1. The results indicate a significant seasonal variation, with maximum concentrations observed in winter, reaching a mean of 342 Bq kg−1 and minimum concentrations in summer, with a mean of 50 Bq kg−1. A statistical analysis was carried out to examine the influence of local meteorological parameters on 7Be concentrations. The analysis reveals a significant positive correlation between 7Be concentrations and precipitation (r = 0.66, p < 0.01), and a negative correlation with temperature (r = − 0.67, p < 0.01). Analysis of prevailing wind directions by season shows that in winter, winds from the east and southeast control overall mean 7Be concentrations. In summer, on the other hand, north and northwest winds contribute less to mean 7Be concentrations. The results of the air mass back-trajectory analysis, combined with the PSCF and CWT source-receiver methods, show that the main source regions for 7Be are the north-east atlantic ocean and continental air masses from Africa. These results are in agreement with observations reported in neighboring regions, such as Canary Islands, Malaga and Granada, Spain.