Keller C, McGrath S P, Dunham S J
Swiss Federal Institute of Technology (EPFL), ENAC-ISTE-LPE, Ecublens, 1015 Lausanne, Switzerland.
J Environ Qual. 2002 Sep-Oct;31(5):1550-60.
To determine whether sludge applications to soil would lead in the short term to toxicity to plants and trace metal leaching to ground water, we studied the fate of some trace and major elements in a brown soil-meadow system just after repeated sewage sludge applications. The main pathways were quantified over a 37-mo period with undisturbed monolith lysimeters including two controls, four lysimeters treated with 3 x 100 m3 ha-1, and four with 3 x 400 m3 ha-1 of sewage sludge. In drainage waters the effect was limited in time and, in the case of NO3-N and Cl, delayed by 1 to 4 mo and lasted several months before returning to background conditions. Nickel and Cu concentrations in solution increased also after sludge application and had not return to background conditions after 20 mo. Trace metal concentrations did not reach toxic levels in herbage and N, Cu, Cd, and Zn concentrations were correlated with the first sludge input only. Calculated over a 37-mo period, total element output was significantly increased for Ca, NO3-N, and Ni only, because of the time-dependent response to sludge application and high variability between replicates. Output was maximal for Cd, with 1.5% of total input for the 100 m3 ha-1 treatment. Particulate matter in drainage water accounted for an average of 20% of trace metal leaching. The main long-term risk was the rapid increase in trace metal concentrations in the topsoil, which may eventually lead to toxic levels in herbage.
为了确定向土壤施用污泥在短期内是否会对植物产生毒性以及微量金属是否会淋溶到地下水中，我们研究了在重复施用污水污泥后，棕色土壤 - 草甸系统中一些微量和常量元素的归宿。在37个月的时间里，使用原状整块渗漏计对主要途径进行了量化，其中包括两个对照、四个以3×100立方米/公顷处理的渗漏计和四个以3×400立方米/公顷处理的污水污泥渗漏计。在排水中，这种影响在时间上是有限的，对于硝酸盐氮和氯来说，影响延迟1至4个月，持续几个月后才恢复到背景条件下水平。施用污泥后溶液中的镍和铜浓度也有所增加，20个月后仍未恢复到背景条件下水平。牧草中的微量金属浓度未达到有毒水平，氮、铜、镉和锌浓度仅与首次污泥输入量呈相关关系。在37个月的时间里进行计算，仅钙、硝酸盐氮和镍的总元素输出量显著增加，这是由于对污泥施用的时间依赖性响应以及重复样本间的高变异性。镉的输出量最大，对于每公顷100立方米的处理，镉输出量占总输入量的1.5%。排水水中颗粒物质平均占微量金属淋溶量的20 %。主要的长期风险是表土中微量金属浓度的迅速增加，这最终可能导致牧草中的有毒水平。
