Impact of a massive dust storm on the gross alpha, gross beta, 40K, 137Cs, 210Pb, 7Be activities measured in atmospheric aerosols collected in Tenerife, Canary Islands

From February 22 to 24, 2020, an intense dust storm affected the Spanish archipelago of the Canary Islands. Here we assess the radiological impact on the Canary Islands population of several natural and artificial radionuclides (K-40, Cs-137, Pb-210, Be-7), and other radiological parameters (gross alpha and gross beta activity concentrations) measured in atmospheric aerosols before, during and after the dust storm. Total Suspended Matter highly correlated with PM10 (Pearson's correlation coefficient, r(o) = 0.98), showed increments ranging from 849% to 1778% against the background average levels, reaching levels of >3000 mu g m(-3). K-40 and Cs-137 radionuclides showed activity values over the minimum detection activity from January to March 2020, coupled with dust intrusion episodes during the study. This finding supports the use of these radionuclides as radiotracers for African low altitude dust intrusions occurring particularly during winter months over the Canary Islands. A high correlation between gross beta and Pb-210 activities suggests that the latter is the main source for gross beta emitters in aerosol samples collected in the study region. Pb-210 and Be-7 showed a moderate positive correlation and did not show any significant change during the storm, suggesting a similar dynamics of alpha and beta emitters in the low atmosphere. A Principal Component Analysis of these observations showed two components representing a Saharan component (based on K-40, Cs-137, gross alpha, and PM10) and a heterogeneous component representing North Atlantic and Europe air masses (based on Be-7, Pb-210, and gross beta). In addition, a K-means cluster analysis helped to disentangle the origin of air masses arriving at the archipelago. Three different clusters were identified: a continental cluster (based on gross beta, Pb-210, and Be-7 activity concentrations); an oceanic cluster (with low values of PM10 air concentrations, gross beta, gross alpha, and Pb-210, and Be-7 and K-40 activity concentrations), reflecting the Atlantic air contributions with lower radionuclide activity and microparticulate matter; and a dust intrusion cluster (with high PM10 values and Cs-137, K-40 and gross alpha activity concentrations) representing dust intrusion episodes observed in Tenerife Island. These studies allow the detection and monitoring of radioactive elements, estimating the potential radiological risk to the population associated with mineral dust intrusions.