Dynamics of Arsenic and Trace Metal Uptake and Translocation in Dominant Plants of High-Andean Wetlands: A Study in the Guaranda Canton, Within the Chimborazo Reserve, Ecuador

High-Andean wetlands regulate water supply, but their volcanic soils may release arsenic and trace metals. We quantified As, Cd, Cr, Hg, and Pb in roots, stems, and leaves of the six dominant species of the seven wetlands of the Guaranda canton of the Chimborazo Fauna Production Reserve, Ecuador. A stratified inventory identified the dominants: Plantago rigida, Azorella aretioides, Lachemilla orbiculata, Juncus balticus, Agrostis breviculmis, and Eryngium humile. Composite organ samples were analysed by atomic absorption spectrometry. Arsenic was present in every tissue (5.15 ± 1.18 mg kg−1 dry weight), above the range typical of uncontaminated plants; Hg was low and uniform (0.66 ± 0.06 mg kg−1), and Pb and Cr were mostly below reporting limits. Cadmium was translocated to leaves in four species but retained in the roots of L. orbiculata and A. aretioides. Principal component analysis, HJ-Biplot, and PERMANOVA showed that species, not organ, structured tissue composition (52.8% vs. 8.8% of variation). All concentrations were two to three orders of magnitude below hyperaccumulation thresholds, so none of the species is a viable phytoextractor. Lachemilla orbiculata and A. aretioides are candidates for phytostabilisation trials, and all six species can serve as As biomonitors. These data provide a baseline for As monitoring in protected Andean wetlands.