Mendoza Jorge, Garrido Tatiana, Castillo Gabriela, San Martin Nilsa
Facultad de Ciencias Químicas y Farmacéuticas, Departamento de Química Inorgánica y Analítica, Universidad de Chile, Olivos 1007, Casilla 233, Santiago 1, Chile.
Chemosphere. 2006 Dec;65(11):2304-12. doi: 10.1016/j.chemosphere.2006.05.012. Epub 2006 Jun 22.
Several factors depending on the sludge, the soil, or the combination of both substrates, may affect element availability to plants. In this study, an assessment was done of the effect of two sludges obtained by different processes (activated sludge and facultative stabilization pond) on heavy-metal availability and uptake by sorghum plants in soils with high and low copper contents. Results obtained for DTPA-extractable metal indicated higher metal availability in sludge-amended soils. In addition, sludges caused changes in copper and zinc distribution in soil, indicating in most cases a discrete increase in the more labile metal forms. However, observed changes did not increase heavy metal concentration in plant leaves, indicating that assessment of metal availability by a chemical procedure (single extraction or metal fractionation) would not permit a good prediction of metal bioavailability. On the other hand, sludge application at a rate of 100 t ha(-1) to high-copper agricultural soils would not imply greater mobility of this metal on account of a greater sorbing capacity provided by the sludges. Such results would indicate that sludges from wastewater treatment plants, meeting the standards of heavy metal contents, regardless of the process by which they were obtained, may be applied to several kinds of soil, even to high-copper soils, with no risk of increasing heavy metal bioavailability to phytotoxic levels in the short range.
取决于污泥、土壤或两种基质组合的几个因素，可能会影响植物对元素的有效性。在本研究中，评估了通过不同工艺获得的两种污泥（活性污泥和兼性稳定塘）对高铜和低铜含量土壤中高粱植物重金属有效性和吸收的影响。DTPA可提取金属的结果表明，污泥改良土壤中金属有效性更高。此外，污泥导致土壤中铜和锌的分布发生变化，在大多数情况下表明更不稳定的金属形态有明显增加。然而，观察到的变化并未增加植物叶片中的重金属浓度，这表明通过化学程序（单次提取或金属分级）评估金属有效性并不能很好地预测金属生物有效性。另一方面，以100 t ha(-1)的施用量将污泥施用于高铜农业土壤，由于污泥提供了更大的吸附能力，不会意味着这种金属有更大的迁移性。这些结果表明，符合重金属含量标准的污水处理厂污泥，无论其获得工艺如何，都可以施用于几种土壤，甚至是高铜土壤，短期内不会有将重金属生物有效性提高到植物毒性水平的风险。
