干旱区生态环境知识资源中心(Arid): Arsenic and iron speciation and mobilization during phytostabilization of pyritic mine tailings

Arid

DOI	10.1016/j.gca.2020.07.001
	Arsenic and iron speciation and mobilization during phytostabilization of pyritic mine tailings
	Hammond, Corin M.; Root, Robert A.; Maier, Raina M.; Chorover, Jon
通讯作者	Chorover, J
来源期刊	GEOCHIMICA ET COSMOCHIMICA ACTA
ISSN	0016-7037
EISSN	1872-9533
出版年	2020
卷号	286 页码:306-323
英文摘要	Particulate and dissolved metal(loid) release from mine tailings is of concern in (semi-)arid environments where tailings can remain barren of vegetation for decades and, therefore, become highly susceptible to dispersion by wind and water. Erosive weathering of metalliferous tailings can lead to arsenic contamination of adjacent ecosystems and increased risk to public health. Management via phytostabilization with the establishment of a vegetative cap using organic amendments to enhance plant growth has been employed to reduce both physical erosion and leaching. However, prior research suggests that addition of organic matter into the oxic weathering zone of sulfide tailings has the potential to promote the mobilization of arsenate. Therefore, the objective of the current work was to assess the impacts of phytostabilization on the molecular-scale mechanisms controlling arsenic speciation and lability. These impacts, which remain poorly understood, limit our ability to mitigate environmental and human health risks. Here we report on subsurface biogeochemical transformations of arsenic and iron from a three-year phytostabilization field study conducted at a Superfund site in Arizona, USA. Legacy pyritic tailings at this site contain up to 3 g kg(-1) arsenic originating from arsenopyrite that has undergone oxidation to form arsenate-ferrihydrite complexes in the top 1 m. Tailings were amended in the top 20 cm with 100,150, or 200 g kg(-1) (300-600 t ha(-1)) of composted organic matter and seeded with native halotolerant plant species. Treatments and an unamended control received irrigation of 360 +/- 30 mm y(-1) in addition to 250 +/- 160 mm y(-1) of precipitation. Cores to 1 m depth were collected annually for three years and sectioned into 20 cm increments for analysis by synchrotron iron and arsenic X-ray absorption spectroscopy (XAS) coupled with quantitative wet chemical and mass balance methods. Results revealed that >80% of arsenic exists in ammonium oxalate-extractable and non-extractable phases, including dominantly ferrihydrite and jarosite. Arsenic release during arsenopyrite oxidation resulted in both downward translocation and As-(v) attenuation by stable Fe-(III) (oxyhydr)oxide and Fe-(III) (hydroxy)sulfate minerals over time, highlighting the need for sampling at multiple depths and time points for accurate interpretation of arsenic speciation, lability, and translocation in weathering profiles. Less than 1% of total arsenic was highlylabile, i.e. water-extractable, from all treatments, depths, and years, and more than 99% of arsenate released by arsenopyrite weathering was attenuated by association with secondary minerals. Although downward translocation of both arsenic and iron was detected during phytostabilization by temporal enrichment analysis, a similar trend was measured for the uncomposted control, indicating that organic amendment associated with phytostabilization practices did not significantly increase arsenic mobilization over non-amended controls. (C) 2020 Elsevier Ltd. All rights reserved.
英文关键词	Phytostabilization Arsenic speciation Iron (oxy)hydroxides Ferrihydrite Jarosite Field-scale Depth profile XAS
类型	Article
语种	英语
开放获取类型	Green Accepted
收录类别	SCI-E
WOS记录号	WOS:000561894400003
WOS关键词	DISSOLVED ORGANIC-MATTER ; NATURAL ATTENUATION ; ASSISTED PHYTOSTABILIZATION ; OXIDE MINERALS ; METALS ; PHYTOREMEDIATION ; SOILS ; ACID ; REMEDIATION ; SORPTION
WOS类目	Geochemistry & Geophysics
WOS研究方向	Geochemistry & Geophysics
来源机构	University of Arizona
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/325771
作者单位	[Hammond, Corin M.; Root, Robert A.; Maier, Raina M.; Chorover, Jon] Univ Arizona, Dept Environm Sci, 1177 E 4th St,Shantz 429, Tucson, AZ 85721 USA
推荐引用方式 GB/T 7714	Hammond, Corin M.,Root, Robert A.,Maier, Raina M.,et al. Arsenic and iron speciation and mobilization during phytostabilization of pyritic mine tailings[J]. University of Arizona,2020,286:306-323.
APA	Hammond, Corin M.,Root, Robert A.,Maier, Raina M.,&Chorover, Jon.(2020).Arsenic and iron speciation and mobilization during phytostabilization of pyritic mine tailings.GEOCHIMICA ET COSMOCHIMICA ACTA,286,306-323.
MLA	Hammond, Corin M.,et al."Arsenic and iron speciation and mobilization during phytostabilization of pyritic mine tailings".GEOCHIMICA ET COSMOCHIMICA ACTA 286(2020):306-323.