Natural zinc enrichment in peatlands: Biogeochemistry of ZnS formation

Soh joung Yoon, Carolina Yáñez, Mary Ann Bruns, Nadia Martínez-Villegas, Carmen Enid Martínez

Resultado de la investigación: Contribución a una revistaArtículorevisión exhaustiva

26 Citas (Scopus)

Resumen

Peatlands effectively retain heavy metals and prevent stream and watershed contamination. Sulfate reduction is considered the most significant process of metal immobilization in natural wetlands and microbial sulfate reduction is the presumed mechanism that results in the precipitation of metal sulfides. In this study, we examined the biogeochemical mechanisms involved in zinc retention and accumulation in a metalliferous peatland of western New York. In the reducing conditions of these peatlands zinc sulfides occurred as framboidal aggregates of sphalerite and polytypic wurtzite (2nH, n≥2) nanocrystallites associated with bacterial cells and organic matter. Bacterial cells were co-located with ZnS inside peat particles where the microenvironment remained anoxic. The peat zinc sulfide was depleted in 34S isotopes relative to the sulfate supplied to the peatland by 18-34 per mill, implicating its biological formation. Extraction of microbial community DNA from peat samples yielded diverse PCR amplicons from dissimilatory sulfite reductase (dsrAB) genes, indicating varied bacterial taxa capable of reducing forms of oxidized sulfur. Nanocrystals with distinct structural features were observed in samples containing contrasting dsrAB sequences. The results of this investigation provide clear evidence that microorganisms can influence the chemical forms of heavy metals in peatland environments. Our findings also provide insight into the conditions necessary to promote the immobilization of chalcophile elements in engineered systems for the treatment of acid mine drainage and wastewater effluents.

Idioma originalInglés
Páginas (desde-hasta)165-176
Número de páginas12
PublicaciónGeochimica et Cosmochimica Acta
Volumen84
DOI
EstadoPublicada - 1 may 2012
Publicado de forma externa

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