Accumulation of Heavy Metals and <scp>PAHs</scp> in Algal Crust on Burning Coal‐Waste Dumps: A Case Study From an Extreme Environment

ABSTRACT Burning coal‐waste dumps are a clear example of anthropogenic landforms that can harm the natural environment in post‐mining regions. In the Upper Silesian Coal Basin (USCB), their surface is often irregularly covered with algal crusts, which can accumulate pollutants very well. To determine the toxicity of these biocrusts on burning dumps and evaluate their role in such extreme conditions, mineral and chemical tests were carried out with a particular focus on heavy metals and polycyclic aromatic hydrocarbons (PAHs). Several environmental indices were used, including the geoaccumulation factor, enrichment factor, contamination factor, ecological risk index, and total carcinogenic risk (TCR). The hazard linked to single PAHs and to the group as a whole in biocrusts was examined, with an average concentration of Σ PAHs reaching 3938.40 μg/kg. Heavy metals such as Zn (avg. 4416.7 ppm), Cd (avg. 25.8 ppm), Pb (avg. 1166.5 ppm), Ni (avg. 327.0 ppm), Cu (avg. 1103.8 ppm) and As (avg. 44.1 ppm) showed elevated concentrations. The combined load of heavy metals and PAHs in the biocrusts indicates a serious environmental threat and potential risks to human health. Environmental indices clearly show that the studied dump represents an extremely contaminated environment, with exceptionally high levels of heavy metal enrichment. The TCR results classify all samples within the high‐risk category. The findings highlight the importance of algal communities in the early stages of colonisation, their potential role in stabilising post‐industrial habitats, and novel insights into combined organic and inorganic pollutant loads in biocrusts under extreme conditions.