Squamate reptiles as bioindicators of trace element exposure in an agricultural landscape of the Brazilian Cerrado

Agricultural intensification in the Cerrado has increased the mobilization of trace elements. This study assessed occurrence and bioaccumulation of trace elements in livers of 12 reptile species (Ameiva ameiva, Ameivula ocellifera, Amerotyphlops brongersmianus, Erythrolamprus macrosomus, Helicops angulatus, Leposternon infraorbitale, Micrablepharus atticolus, Notomabuya frenata, Philodryas patagoniensis, Phimophis guerini, Pseudoboa nigra, and Trilepida koppesi), as well as in water and soil samples, from the headwaters of the Araguaia River, Brazil. Samples were collected at five sites; concentrations were determined by inductively coupled plasma optical emission spectrometry (ICP-OES). Trace element concentrations showed distinct distribution patterns in water, soil, and reptile liver samples. Within each matrix, significant differences were detected among trace elements, whereas no significant differences were observed among sites or species. Bioaccumulation factors indicated enrichment for Pb, Cd, Fe, and V, demonstrating reptile accumulation of these elements. Multivariate analyses revealed spatial patterns in liver concentrations, including the separation of one site. The correspondence between soil trace element concentrations and reptile bioaccumulation patterns suggests that soil may represent an exposure compartment. Multivariate patterns of Hg and Cd may reflect differences in distribution or exposure pathways. These findings support reptiles as bioindicators and highlight the importance of assessing contaminant dynamics in tropical agricultural landscapes.