Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
Chemosphere. 2010 Jan;78(4):389-96. doi: 10.1016/j.chemosphere.2009.11.008. Epub 2009 Dec 3.
The effects of long-term application of different organic amendments, as compared to mineral fertilizer, on Zn, Cu and Pb content and leachability in a luvisol derived from loess were assessed. The organic fertilizers, applied since 1962, were compost (COM) - from green organic household waste, sewage sludge (SLU) - from municipal water treatment facilities, farmyard manure (FYM) and the doses applied since 1997 were 90tha(-1), 10tha(-1) and 9tha(-1), once in 3years, respectively. The kinetics of metals extraction with 0.05moldm(-3) EDTA at pH 6.0 has been studied. The two first-order reactions model was fitted to the kinetic data and allowed to distinguish two pools for each metal: a "labile" fraction (Q(1)), quickly extracted with a rate constant k(1), and a "moderately labile" fraction (Q(2)), more slowly extracted, with a rate constant k(2). Simultaneously, the pseudo-total metal contents in the soil samples were determined after digestion with aqua regia (3:1 HCl+HNO(3)). The obtained parameters Q(1), k(1), Q(2), k(2), for the kinetics of extraction of each metal in the three replicates of each fertilization mode, as well as the pseudo-total metal contents, were statistically analysed. COM and SLU application resulted in an increase of the total contents of Pb, Zn and Cu in soil. Further, the percentage of labile Zn and Pb also increased in consequence of the application of those amendments, particularly COM. The increase was more noticeable for Zn. FYM, despite not increasing the total content of Pb, Zn or Cu, did also have an effect on the leachability of Zn and Pb, increasing their labile fraction in soil. These results point to a potential risk of increasing metals mobility in soil, mainly Zn, associated to the use of organic amendments, particularly COM or SLU.
在黄土发育的淋溶土中，评估了与矿物肥料相比，长期施用不同有机肥料（堆肥[COM]——来自绿色有机家庭废物、污泥[SLU]——来自城市水处理设施、农家肥[FYM]）对 Zn、Cu 和 Pb 含量和可浸出性的影响。自 1962 年以来，一直施用这些有机肥料，COM、SLU 和 FYM 的施用量分别为 90tha(-1)、10tha(-1)和 9tha(-1)，每 3 年施用一次。研究了用 0.05moldm(-3)EDTA 在 pH 6.0 下提取金属的动力学。用两个一级反应模型对动力学数据进行拟合，允许为每种金属区分两个库：一个“不稳定”分数（Q(1)），用速率常数 k(1)快速提取，一个“中等不稳定”分数（Q(2)），用较慢的速率常数 k(2)提取。同时，用王水（3:1 HCl+HNO(3)）消化后测定土壤样品中的金属总量。在三种施肥模式的每个重复中，对动力学提取每种金属的 Q(1)、k(1)、Q(2)、k(2)等参数以及金属总量进行了统计分析。COM 和 SLU 的施用导致土壤中 Pb、Zn 和 Cu 的总量增加。此外，由于施用这些肥料，特别是 COM，可提取的 Zn 和 Pb 百分比也增加了。Zn 的增加更为明显。尽管 FYM 没有增加 Pb、Zn 或 Cu 的总量，但它也会影响 Zn 和 Pb 的可浸出性，增加土壤中 Zn 的可提取分数。这些结果表明，与使用有机肥料（特别是 COM 或 SLU）相关联，土壤中金属迁移性增加的潜在风险增加，主要是 Zn。
