Assessment of potentially toxic elements in soil and air: Application of bioindicator methods in environmentally polluted area

Environmental components in historically mined areas are frequently threatened by elevated concentrations of potentially toxic elements (PTEs), yet many sites remain insufficiently investigated. This pilot study assessed soil and airborne PTEs (As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Zn) and soil macronutrients (Ca, K, Mg, Na) across mine, heap, and forest sites using bioindication methods. Soil enzyme activities were evaluated as indicators of soil health, while mosses (Pleurosium sp., Climacium sp.) and lichen (Pseudevernia sp.) were used for air biomonitoring. Soil contamination was assessed using the contamination factor (Cf), and atmospheric pollution using the relative accumulation factor (RAF). Cadmium exceeded legal limits at all sites, whereas heaps represented the primary pollution source, with average enrichments exceeding 47-fold for As, 80-fold for Cu, and 109-fold for Hg. Acidic soils and reduced macronutrient contents likely enhanced metal mobility and bioavailability. Principal component analysis showed strong associations among PTEs and negative correlations with Ca, K, and Mg. Acid and alkaline phosphatase activities were negatively, in some cases significantly, correlated with most PTEs. Biomonitoring confirmed atmospheric deposition, with mean RAF values of 3.59 for Cd and 2.81 for Pb. Pseudevernia sp. proved the most effective airborne accumulator.