RT Journal Article
T1 A method for studying the influence of Mn oxyhydroxides on the trace element content of aquatic bryophytes
A1 Real Rodríguez, Carlos
A1 Villares Pazos, Rubén
A1 Vázquez Castro, María Dolores
K1 Bryophytes
K1 River
K1 Biomonitoring
K1 Mn oxyhydroxides
K1 Dihidroxylamine extraction
K1 Gamma distribution
AB The main objective of this study was to develop and test a method of separating externally deposited Mn oxyhydroxides and co-precipitated elements from samples of aquatic moss (the moss Fontinalis antipyretica). The method, which uses 0.1 M hydroxylamine to dissolve the oxyhydroxides, was tested with samples collected in rivers with slightly acidic, well‑oxygenated waters, where high rates of Mn precipitation occur. The method was effective (it extracted up to 84 % of the Mn) and selective (Fe oxyhydroxides were not extracted). The elements Ba, Cd, Zn and Ni were associated with the Mn oxyhydroxides, while Al, As, Cr, Cu, Fe, Hg and Pb were not. Deposition of Mn therefore increased the concentration of some elements in the moss samples. However, as Mn precipitation depends on Eh and pH, which are independent of the concentrations of the elements in water, the relationship between water and moss element concentrations is not clear (i.e. the data are noisy). This is a problem in biomonitoring studies, which assume a close relationship between element concentrations in moss and water. The value of the proposed extraction method is that it can be used to correct the effect of Mn deposition. We present an example of this correction applied to the Cd concentrations in the test data. We found that the noise introduced by the Mn, including age-related effects (observed by comparing concentrations in 0–2.5 and 2.2–5.0 cm sections from the shoot apex), can be reduced. Additionally, the correction revealed recent increases in Cd concentrations in one site that were not observed in the uncorrected data. Another finding of interest was the low content of total Mn and different extractability (of most elements) observed in moss samples collected in alkaline waters. Finally, we discuss how future studies designed for different environmental scenarios can benefit from application of the proposed method.
PB Elsevier
SN 0048-9697
YR 2024
FD 2024
LK http://hdl.handle.net/10347/34929
UL http://hdl.handle.net/10347/34929
LA eng
NO Science of The Total Environment Volume 932 , 1 July 2024, 173045
NO This work was supported by Ministerio de Ciencia, Innovación y Universidades (Spain) project CTM2015-70578-P. The authors belong to the Galician Competitive Research Group GRC/GPC2016-002. These programs are co-funded by FEDER (EU). The sources of funding did not intervene in the preparation of the research or the paper. Authors would like to thank RIAIDT-USC for the use of its analytical facilities.
DS Minerva
RD 29 abr 2026