Trace elements in Sphagnum moss from remote bogs in northwestern Canada: establishing contemporary reference values

Barraza F.; Arévalo-Hernández C.O.; Bujaczek T.; Devito K.; Mullan-Boudreau G.; Thirupurasanthiran S.; Shotyk W. · Environmental Science: Atmospheres (2026) · DOI: 10.1039/d6ea00079g

Resumen

Mosses are effective biomonitors of atmospheric trace element (TE) deposition, yet modern baseline data for undisturbed peatlands remains scarce. This study establishes reference concentrations using Sphagnum moss collected in 2015 from three ombrotrophic bogs in northwestern Alberta, Canada. Low ash and acid-insoluble ash concentrations previously reported for these samples indicate minimal soil mineral dust influence. To evaluate methodological robustness, two microwave-assisted digestion methods (HNO3 and HNO3 + HBF4) were compared, and elements were analyzed using ICP-OES and ICP-MS. While recoveries of reference plant materials were generally comparable, the addition of HBF4 significantly enhanced the release of some lithophile elements (Al, Co, Cr). Despite minor spatial variations, element concentrations were consistent across sites, suggesting regionally homogeneous background deposition. Principal component analysis (63.5%) identified two dominant controls: a lithogenic gradient (PC 1: 51%) and a biological-nutrient gradient (PC 2: 12.5%). Enrichment factors (EFs) calculated using Al and Sc, revealed that most lithophile (Ba, Co, REEs) and some chalcophile (As, Pb, Tl) elements had EFs ≤ 10, consistent with predominantly crustal origins. Conversely, Cd, Mn, P, S, Se, and Zn showed EFs ≥ 100, reflecting strong biological cycling and/or non-crustal inputs. The Pb/Sc ratio in the Sphagnum moss (4.9) is similar to the values reported for mid-Holocene peat from a bog in Switzerland (4) and Arctic ice from Canada (6.3), suggesting minimal contemporary anthropogenic influence. This dataset of 51 elements provides a robust baseline for Sphagnum moss from boreal ombrotrophic peatlands, and may serve as a reference for regional and global studies of atmospheric deposition. This journal is © The Royal Society of Chemistry, 2026.

Instituciones: Universidad Nacional Autónoma de Alto Amazonas