Evernia goes to school: Bioaccumulation of heavyMetals and photosynthetic performance in lichenTransplansexposed indoors and outdoors in public and private environments

Abstract

Recently indoor air quality (IAQ) has become a key issue, especially in schools, where children spend most of the day. Only in a few cases IAQ was investigated using lichens as biomonitors. During autumn 2017, lichens (Evernia prunastri) were exposed for two months indoorsand outdoors in public (schools) and private (dwellings) environments, in both rural and urbanareas of Slovakia. The bioaccumulation of selected elemnnts and the physiological status of thesamples were considered. The content of heavy metals increased in samples exposed outdoors for 11 out of 12 elements (Al, As, Cd, Cr, Cu, Fe, Pb, S, Sb, V and Zn, but not Ca) in the urban area and for 5 (As, Cd, Cu, Pb and Sb) in the ruraaarea. Indoor concentrations were overall similar, both in rural and urban buildings, independently of the outdoor conditions. An indoor accumulation occurred only for Cd, Cu and Pb. An indoor origin was suggested for Cd, while for Cu and Pb,outdoor penetration (car traffic) is the likelycause of indoor values. Indoor exposed lichens maintained their vitality (as reflected by chlorophyll a fluorescence emission). This latter result further supports the use of lichen biomonitoring as a suitable method for assessing IAQ.