Huang Jen-How, Matzner Egbert
Department of Soil Ecology, University of Bayreuth, D-95440 Bayreuth, Germany.
Environ Pollut. 2007 Sep;149(2):201-8. doi: 10.1016/j.envpol.2007.01.004. Epub 2007 Jul 10.
To identify the role of the forest floor in arsenic (As) biogeochemistry, concentrations and fluxes of inorganic and organic As in throughfall, litterfall and forest floor percolates at different layers were investigated. Nearly 40% of total As(total) input (5.3g Asha(-1)yr(-1)) was retained in Oi layer, whereas As(total) fluxes from Oe and Oa layers exceeded the input by far (10.8 and 20g Asha(-1)yr(-1), respectively). Except dimethylarsinic acid (DMA), fluxes of organic As decreased with depth of forest floor so that <10% of total deposition (all <0.3g Asha(-1)yr(-1)) reached the mineral soil. All forest floor layers are sinks for most organic As. Conversely, Oe and Oa layers are sources of As(total), arsenite, arsenate and DMA. Significant correlations (r>/=0.43) between fluxes of As(total), arsenite, arsenate or DMA and water indicate hydrological conditions and adsorption-desorption as factors influencing their release from the forest floor. The higher net release of arsenite from Oe and Oa and of DMA from Oa layer in the growing than dormant season also suggests microbial influences on the release of arsenite and DMA.
为了确定森林地表层在砷（As）生物地球化学中的作用，对不同层次的穿透雨、凋落物和森林地表层渗滤液中无机和有机砷的浓度及通量进行了研究。总砷（total）输入量（5.3 g As ha⁻¹ yr⁻¹）中近40%保留在Oi层，而来自Oe层和Oa层的总砷通量远远超过输入量（分别为10.8和20 g As ha⁻¹ yr⁻¹）。除二甲基砷酸（DMA）外，有机砷通量随森林地表层深度的增加而降低，以至于到达矿质土壤的总沉降量不到10%（均<0.3 g As ha⁻¹ yr⁻¹）。森林地表层的所有层次都是大多数有机砷的汇。相反，Oe层和Oa层是总砷、亚砷酸盐、砷酸盐和DMA的源。总砷、亚砷酸盐、砷酸盐或DMA通量与水分之间存在显著相关性（r≥0.43），这表明水文条件和吸附 - 解吸是影响它们从森林地表层释放的因素。在生长季节，Oe层和Oa层中亚砷酸盐以及Oa层中DMA的净释放量高于休眠季节，这也表明微生物对亚砷酸盐和DMA的释放有影响。
