Arsenic speciation and reactivity in poultry litter
Arsenic speciation and reactivity in poultry litter
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DOI：
10.1021/es0340580
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发表时间：
2003-09-15
影响因子：
11.4
通讯作者：
Sparks, DL
中科院分区：
文献类型：
--
作者：
Arai, Y;Lanzirotti, A;Sparks, DL
最近，美国政府采取行动，降低饮用水中总砷（As）的最大浓度水平（MCL） （10 ppb），这引起了人们对农业使用含砷生物固体（如家禽垃圾（PL））的严重关注。在这项研究中，利用新型同步加速器探测技术（微聚焦（mu）同步加速器x射线荧光（SXRF）和mu- x射线吸收近边缘结构（XANES）光谱）结合化学消化和批量实验，研究了PL和长期改性土壤中的固态化学形态、解吸性和总砷水平。PL中的总砷含量高达约50 mg kg(-1)，并且砷（II/III和V）总是集中在与Ca， Cu和Fe相关的大量针状微观颗粒（约20 μ m × 850 μ m）中，与S， Cl和Zn相关的较少。凋落物颗粒的边缘后XANES特征与家禽饲料中的有机as (V)化合物（即洛克沙胂）不同，这表明洛克沙胂可能在凋落物和/或家禽消化道中降解/转化。从4.5到7，随时间的增加和pH值的增加，As的解吸程度增加，但在pH为7的条件下，5 d后最多释放15%的As，这表明存在不溶相和/或强保留的可溶性化合物。无显著的As积累(
Recent U.S. government action to lower the maximum concentration levels (MCL) of total arsenic (As) (10 ppb) in drinking water has raised serious concerns about the agricultural use of As-containing biosolids such as poultry litter (PL). In this study, solid-state chemical speciation, desorbability, and total levels of As in PL and long-term amended soils were investigated using novel synchrotron-based probing techniques (microfocused (mu) synchrotron X-ray fluorescence (SXRF) and mu-X-ray absorption near-edge structure (XANES) spectroscopies) coupled with chemical digestion and batch experiments. The total As levels in the PL were as high as approximate to50 mg kg(-1), and As(II/III and V) was always concentrated in abundant needle-shaped microscopic particles (approximate to20 mum x 850 mum) associated with Ca, Cu, and Fe and to a lesser extent with S, Cl, and Zn. Post-edge XANES features of litter particles are dissimilar to those of the organo-As(V) compound in poultry feed (i.e., roxarsone), suggesting possible degradation/transformation of roxarsone in the litter and/or in poultry digestive tracts. The extent of As desorption from the litter increased with increasing time and pH from 4.5 to 7, but at most 15% of the total As was released after 5 d at pH 7, indicating the presence of insoluble phases and/or strongly retained soluble compounds. No significant As accumulation (