Biomonitoring of potentially toxic elements in mosses: a case study of cities in Perm region, Russia

Small industrial cities are less frequently investigated for the presence of potentially toxic elements (PTEs) in ambient air, although these pollutants pose a serious threat to the environment, economy, and public well-being. Passive moss biomonitoring was applied to assess air quality in three industrial cities (Solikamsk, Berezniki, and Gubakha) of the Perm region, Russia. All three cities, dominated by the chemical, metallurgical, and mining industries, are major centers of industrial development in the region. The elemental composition of moss samples was determined using inductively coupled plasma optical emission spectrometry and a Milestone DMA-80 direct mercury analyser. Correlation analysis, factor analysis, and principal component analysis were applied to identify relationships among the elements and their possible emission sources. The results showed that the main sources of PTEs are industrial activities, including chemical, metallurgical, and coke-chemical production, as well as coal and oil combustion and vehicle emissions. To assess the degree of air pollution, contamination factor (CF), pollution load index (PLI), and ecological risk index (RI) were calculated. The PLI values for Solikamsk, Berezniki, and Gubakha were 1.35, 1.69, and 1.56, respectively, indicating pollution levels ranging from unpolluted to moderately polluted. For most elements, the potential ecological risk (PER) values indicated a low level of ecological risk. However, moderate potential ecological risks were identified for Hg in all three cities, with values ranging from 42.8 to 49.4, and for Cd in Gubakha, with a value of 66.1. The overall risk index ranged from 87 in Solikamsk to 137 in Gubakha, indicating a low overall ecological risk in all three cities.