Tracking environmental changes in atmospheric deposition in Moscow region with mosses as biomonitors: from pre-pandemic to post-pandemic periods.

The COVID-19 pandemic had a profound negative impact on human health and economies worldwide. To assess whether mosses can effectively detect short-term changes in air pollution levels, the results of moss survey from pre-pandemic (2019) period were compared with those from pandemic (2020) and post-pandemic (2021) periods. The content of potentially toxic elements, Cd, Cr, Cu, Fe, Ni, Pb, in the moss samples collected in the Moscow region was determined using atomic absorption spectroscopy (in 2019 and 2020) and inductively coupled plasma atomic emission spectroscopy (in 2021). The Kruskal-Wallis test revealed significant differences in Cd, Cu, and Pb content in moss samples collected during different periods, while the content of Cr, Ni, and Fe showed no notable changes. The correlation and principal component analyses were applied to identify association between elements and link them with sampling sites and potential emission sources. Our findings suggest that COVID-19-related changes influenced the variations in the content of potentially toxic elements in moss samples collected in the Moscow region.