Syntrichia ruralis as a suitable bioindicator for urban areas – the case study of Tallinn city

Environmental pollution is one of the most important problems in urban environment. Mosses are good indicatorsof air pollution. In Estonia, heavy metals have been measured from Pleurozium schreberi and Hylocomium splendens, whichdo not grow in areas of Tallinn with a higher pollution load. In the present study, Cu, Fe and Cd were measured from fivemoss species growing in contaminated as well less polluted areas of Tallinn. Based on stationary and street pollution sourceinventory and air pollution dispersion modelling, the long-term average concentrations of fine particles (PM10) and nitrogenoxides (NOx) in air were estimated. The work revealed that it is possible to find a moss species that is common in Tallinnand grows in both polluted and less polluted areas – Syntrichia ruralis, which is the most suitable species for bioindicationbased on this work. Moss species Ceratodon purpureus accumulated the most Cd, Cu, and Fe, then Brachytheciumrutabulum/Sciuro-hypnum curtum, and Rhytidiadelphus squarrosus the least. Statistically significant higher Fe concentrationswere in the Syntrichia ruralis, compared to the Sciuro-hypnum curtum and Rhytidiadelphus squarrosus. The Syntrichia ruralisalso had significantly higher Cd content compared to the Brachythecium rutabulum/Sciuro-hypnum curtum. The results ofthe GLM analysis showed that the content of various heavy metals depends on the moss species and the degree of fine particlesin the environment, and it didn't depend on whether the moss grows on the soil or a hard substrate such as concrete, stoneor asphalt.