Geochemical weathering increases lead bioaccessibility in semi-arid mine tailings.
Geochemical weathering increases lead bioaccessibility in semi-arid mine tailings.
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DOI：
10.1021/es300603s
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发表时间：
2012-06-05
影响因子：
11.4
通讯作者：
Chorover, Jon
中科院分区：
文献类型：
--
作者：
Hayes, Sarah M.;Webb, Sam M.;Bargar, John R.;O'Day, Peggy A.;Maier, Raina M.;Chorover, Jon
矿山尾矿可能含有高浓度的有毒金属（loid），对周围社区和生态系统构成重大危害。风成的运输，能够易位小（微米级）的颗粒，可以是在干旱或半干旱景观有毒金属扩散的主要机制。人类可通过直接吸入或摄入颗粒物接触金属。测量剂量的总铅（Pb）在geodia相关性差，血液铅水平的事实突出了需要更好地解决复杂的颗粒混合物中的分子物种的金属轴承相的精确分布。物种分布控制生物可及性，从而直接影响健康风险。本研究旨在关联含铅的颗粒大小和矿物组成的不稳定性和生物可及性在矿山尾矿进行风化在半干旱环境。我们采用X射线吸收光谱（XAS）和X射线荧光（XRF），再加上连续的化学提取，研究铅形态的尾矿从半干旱的亚利桑那州Klondyke国家超级基金网站。选择pH值为2.6 ~ 5.4的代表性样品进行Pb固相形态的深入研究。主要的含铅相是铅黄钾铁矾（PbFe 6（SO 4）4（OH）12），但角闪石（PbSO 4）和氧化铁吸附铅也观察到。在这项研究中确定的最生物可利用的矿物种类铅，是富集在硫化尾矿样品，其中铅的浓度在粘土大小的部分是2-3倍高的质量相对于散装。一个移动的和生物可及的铅相积累在硫化物尾矿中，人类暴露于大气颗粒物的风险相应增加。
Mine tailings can host elevated concentrations of toxic metal(loid)s that represent a significant hazard to surrounding communities and ecosystems. Eolian transport, capable of translocating small (micrometer-sized) particles, can be the dominant mechanism of toxic metal dispersion in arid or semi-arid landscapes. Human exposure to metals can then occur via direct inhalation or ingestion of particulates. The fact that measured doses of total lead (Pb) in geomedia correlate poorly with blood Pb levels highlights a need to better resolve the precise distribution of molecularly-speciated metal-bearing phases in the complex particle mixtures. Species distribution controls bioaccessibility, thereby directly impacting health risk. This study seeks to correlate Pb-containing particle size and mineral composition with lability and bioaccessibility in mine tailings subjected to weathering in a semi-arid environment. We employed X-ray absorption spectroscopy (XAS) and X-ray fluorescence (XRF), coupled with sequential chemical extractions, to study Pb speciation in tailings from the semi-arid Arizona Klondyke State Superfund Site. Representative samples ranging in pH from 2.6 to 5.4 were selected for in-depth study of Pb solid-phase speciation. The principle lead-bearing phase was plumbojarosite (PbFe6(SO4)4(OH)12), but anglesite (PbSO4) and iron oxide-sorbed Pb were also observed. Anglesite, the most bioavailable mineral species of lead identified in this study, was enriched in surficial tailings samples, where Pb concentrations in the clay size fraction were 2–3 times higher by mass relative to bulk. A mobile and bioaccessible Pb phase accumulates in surficial tailings, with a corresponding increase in risk of human exposure to atmospheric particles.
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影响因子：
11.4
作者：
DAVIS, A;DREXLER, JW;NICHOLSON, A
通讯作者：
NICHOLSON, A
影响因子：
3.4
作者：
Hudson-Edwards, KA;Schell, C;Macklin, MG
通讯作者：
Macklin, MG
影响因子：
11.4
作者：
Arai, Y;Lanzirotti, A;Sparks, DL
通讯作者：
Sparks, DL
影响因子：
2.1
作者：
EISENBERGER, P;BROWN, GS
通讯作者：
BROWN, GS
影响因子：
158.5
作者：
Canfield, RL;Henderson, CR;Lanphear, BP
通讯作者：
Lanphear, BP