Comment on “New insights into the biomineralization of mercury selenide nanoparticles through stable isotope analysis in giant petrel tissues”

• Published in: Journal of Hazardous Materials
• Main Author: Manceau, Alain
• Other Authors: Institut des Sciences de la Terre (ISTerre), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement IRD : UR219-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Université Gustave Eiffel-Université Grenoble Alpes (UGA)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2022
• Subjects: Isotope fractionation; toxicology; bird; HgSe; mercury selenide; selenoprotein P; [SDV.TOX.ECO]Life Sciences [q-bio]/Toxicology/Ecotoxicology; [SDV.BBM.BC]Life Sciences [q-bio]/Biochemistry; Molecular Biology/Biochemistry [q-bio.BM]; Giant Petrel; Giant Petrels
• Online Access: https://hal.archives-ouvertes.fr/hal-03688535; https://hal.archives-ouvertes.fr/hal-03688535/document; https://hal.archives-ouvertes.fr/hal-03688535/file/Comment_HAZMAT_2022_HAL.pdf; https://doi.org/10.1016/j.jhazmat.2022.128583

International audience Some birds and cetaceans can demethylate the toxic methylmercury cysteinate (MeHgCys) complex into inert mercury sulfide (HgSe) through the formation of an intermediate tetrahedral selenolate complex with selenocysteine (Sec) residues (Hg(Sec)4). The nucleation of the HgSe biominerals involves the substitution of the Se ligand for the Sec residues, which is considered to occur in the form of multinuclear Hgx(Se,Sec)y clusters mediated by proteins. Queipo-Abad et al. (2022) isolated HgSe nanoparticles from the biological tissues of giant petrels and measured the mass-dependent fractionation of the 202Hg isotope (δ202Hg). They concluded that the δ202Hg values of the HgSe nanoparticles from each tissue of individual petrels are specific to the HgSe species alone and that the Hg(Sec)4 → HgSe reaction occurs without fractionation of the 202Hg isotope. We show (1) that the HgSe nanoparticles are likely mixtures of MeHgCys, Hg(Sec)4, and HgSe, and therefore that the δ202Hg values are not species-specific, and (2) that the 202Hg isotope is actually fractionated during the Hg(Sec)4 → HgSe reaction, and therefore that this isotope can be used to trace the Hg metabolic pathways between tissues in a single individual and in different animals