Biomonitoring of airborne trace elements using in situ and transplanted lichens around a recycling industry

The concentrations of six metals (Al, Cr, Cu, Fe, Pb and Zn) were analysed in the lichen Evernia prunastri to evaluate the air quality in the surroundings of a tyre and Cu cable recycling industry in Leon, Spain. We evaluated the effect of atmospheric emissions from this industry on lichen samples collected in the area (in situ) and on transplants taken from a reference site. The study area was divided into eight transects according to orientation and the sites were located at increasing distance from the pollution source. Pollution maps with Kriging interpolation method were elaborated. Moreover, Generalised Linear Model, Principal Components Analysis and Spearman's correlations were used. The results showed that the lichen samples collected and exposed near the industry accumulated higher concentrations of these metals, decreasing with the distance and in the direction of the prevailing winds. In situ samples showed higher concentration than transplants. Among elements, Cu was significantly higher around the industrial area, followed by Zn. Elements with similar behaviour and common sources were detected. This study highlights the presence of anthropogenic atmospheric pollution associated with the recycling industry, which may pose a potential environmental and public health concern for nearby populations.