Fecal Evidence of Metal and Metalloid Exposure in a Free-Ranging Juvenile Southern Elephant Seal (Mirounga leonina) From the Brazilian Coast.

Southern elephant seals are highly mobile marine predators that can reflect environmental exposure to chemical elements through their diet and foraging ecology. However, information on elemental concentrations in elephant seal feces remains scarce, particularly outside Antarctic regions. In this study, the concentrations of several metals and metalloids, including rarely studied technology-critical elements, were determined in fecal samples from a juvenile male southern elephant seal (Mirounga leonina) from along the southwestern Atlantic coast of Brazil. Elemental analyses revealed the predominance of biologically essential elements such as Ca and Fe, whereas toxic elements generally occurred at lower concentrations. Rare earth elements, as well as Li, Rb, and Ti were also detected, consistent with recent dietary exposure. Comparisons with previous Antarctic studies indicated overall similar or lower concentrations for most elements, although higher concentrations of As, Be, Cs, Cu, Rb, and U were observed herein. These differences may be associated with regional environmental conditions as well as ontogenetic variations in diet between juvenile and adult individuals. This study provides the first baseline data on elemental concentrations in southern elephant seal feces from the southwestern Atlantic and highlights the usefulness of feces as a non-invasive matrix for monitoring recent environmental exposure in marine ecosystems.