Air Deposition of Heavy Metals in the Prishtina Region Using Mosses and Lichens as Bioindicators

Heavy metal pollution is an important environmental issue in urban and industrial areas because these elements persist in the environment and may cause ecological and health problems. The aim of this study was to investigate the atmospheric deposition of heavy metals (Cu, Mn, Ni, Pb, Zn, and Cr) in the Prishtina region (Kosovo) using mosses and lichens as bioindicators. A total of 24 moss samples (Hypnum cupressiforme) and 9 lichen samples (Cladonia portentosa) were collected between June and August 2025. The plant samples were digested using aqua regia and analysed by Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES). Multivariate statistical methods, including basic statistics, Pearson correlation, and principal component analysis (PCA), together with spatial distribution analysis of heavy metals, were applied to facilitate clearer data interpretation. To evaluate the degree of heavy metal contamination at individual sites and across the entire region, four pollution indices (CF, PLI, Eri, and PERI) were calculated. The results indicate that the study area is contaminated with nickel, chromium, and lead, mainly due to mining activities at the open-pit ferronickel mines in Golesh, emissions from the ferronickel smelter in Drenas, and heavy traffic along the Prishtina-Peja highway. The ecological risk index (Eri) for nickel in moss samples ranged from 6.00 to 336, while in lichen samples it ranged from 6.00 to 42.0. Copper showed Eri values of 6.67-16.67 in mosses and 3.33-5.00 in lichens. For lead, Eri values in moss samples ranged from 3.33 to 53.33, whereas in lichens they were below the detection limit. Based on moss data, 9 locations (39.1 %) were classified as moderately polluted, while 14 locations (60.9 %) fell into the unpolluted to moderately polluted category. In lichen samples, 3 locations (37.5 %) were classified as unpolluted and 5 locations (62.5 %) as unpolluted to moderately polluted. Overall, both the concentrations and pollution indices of heavy metals in mosses were 2-7 times higher than those observed in lichens at the same sampling locations. The smaller number of lichen samples compared with moss samples reflects their limited presence at several sampling sites, which represents a limitation of the study.