Schlich Karsten, Hoppe Martin, Kraas Marco, Fries Elke, Hund-Rinke Kerstin
Fraunhofer Institute for Molecular Biology and Applied Ecology, Auf dem Aberg 1, Schmallenberg, 57392, Germany.
Federal Institute for Geosciences and Natural Resources, Stilleweg 2, Hannover, 30655, Germany.
Ecotoxicology. 2017 Aug;26(6):738-751. doi: 10.1007/s10646-017-1805-4. Epub 2017 May 25.
Sewage sludge is repeatedly applied as fertilizer on farmland due to its high nutrient content. This may lead to a significant increase of silver nanomaterials (AgNM) in soil over years. Therefore, our aim was to investigate the ecotoxicity and fate of AgNM under environmentally relevant conditions in outdoor lysimeters over 25 months. Two AgNM concentrations (1.7 and 8.0 mg/kg dry matter soil) were applied via sewage sludge into soil. In subsamples of the soil, incubated under laboratory conditions for 180 days, the comparability of outdoor and laboratory results regarding ecotoxicity was determined. The results from our long term lysimeter experiments show no detectable horizontal displacement in combination with very low remobilization to the percolate water. Thus, indicate that the sludge applied AgNM remains nearly immobile in the pathway between soils and leachate. However, Ag uptake to the roots of wheat and canola suggests that the chemical conditions in the rhizosphere induce AgNM remobilization from the incorporated sewage sludge even after two harvesting cycles. At the higher AgNM concentration a steady inhibition of the soil microflora was observed over 25 month in the lysimeter study, while there was no effect at the lower AgNM concentration. The results of the laboratory experiment reflect the findings of the lysimeter study and indicate that a risk assessment for AgNM based on data from laboratory tests is acceptable.
由于污水污泥养分含量高，其被反复用作农田肥料。多年来，这可能导致土壤中银纳米材料（AgNM）显著增加。因此，我们的目标是在长达25个月的户外渗漏计中，研究环境相关条件下AgNM的生态毒性和归宿。通过污水污泥向土壤中施加两种AgNM浓度（1.7和8.0毫克/千克干物质土壤）。在实验室条件下培养180天的土壤子样本中，确定了户外和实验室关于生态毒性结果的可比性。我们长期渗漏计实验的结果表明，没有检测到水平位移，同时向渗滤水的再迁移非常低。因此，表明污泥施加的AgNM在土壤和渗滤液之间的路径中几乎保持不动。然而，小麦和油菜根部对银的吸收表明，即使经过两个收获周期，根际的化学条件也会促使AgNM从掺入的污水污泥中再迁移。在较高的AgNM浓度下，渗漏计研究在25个月内观察到土壤微生物群受到持续抑制，而在较低的AgNM浓度下则没有影响。实验室实验结果反映了渗漏计研究的结果，并表明基于实验室测试数据对AgNM进行风险评估是可以接受的。
