Assessing potentially toxic element contamination in bat guano as a bioindicator of habitat pollution: a pilot study across Bosnia and Herzegovina
ABSTRACT Guano samples were collected from nine bat roosts across Bosnia and Herzegovina (caves, tunnels and an abandoned underground quarry) between August 2021 and November 2022. Samples originated from colonies of both sedentary and migratory species. Concentrations of potentially toxic elements (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn) were analysed using flame atomic absorption spectrometry (FAAS). A composite PTI (based on normalised Cd, Cu, Pb and Zn) was calculated to support spatial screening, and KDE mapping was used to visualise the clustering of higher-index sites. Two sites showed evidence of direct anthropogenic pressure, while several others may have been indirectly influenced. Sites associated with anthropogenic activities were compared with those outside apparent pollution sources. The highest concentrations were observed for Fe, Zn, Mn and Cu. Marked interspecific differences at the same site suggest that migratory behaviour and roosting habits may modulate exposure to pollutants. This pilot study provides baseline data for Bosnia and Herzegovina and supports the use of bat guano as a non-invasive biomonitoring matrix for PTE contamination.