Traces elements in feces of Eurasian otters from the mountain stream Javorinka (Slovakia).

The aim of this study was to evaluate the concentrations of elements and heavy metals (Hg, P, S, Cl, K, Ca, Ti, Cr, Mn, Fe, Cu, Zn, Se, Rb, Sr, Zr, Mo, Sb, Ba, and Pb) in fecal samples of the river otter (Lutra lutra) which inhabits the Javorinka mountain stream in the High Tatras, part of the Western Carpathians in Slovakia. Javorinka serves as a model stream with minimal human impact. As a predator, the otter is a suitable bioindicator of the environment it inhabits. Elements and heavy metals were analyzed using the energy-dispersive X-ray fluorescence (ED-XRF) technique due to its simple sample preparation requirements. Mercury was analyzed using a DMA-80 evo mercury analyzer to ensure the accurate detection of low mercury concentrations. Principal component analysis (PCA) was used to identify environmental differences in elemental and heavy metal accumulation, revealing distinct patterns influenced by water flow velocity, elevation, and prey availability. Notably, mercury showed significant seasonal variation in spring, decline, likely related to changes in the otter's food sources. Other elements, such as sulfur, zinc, and iron, exhibited complex interactions and seasonal dependencies.