NEIKER-Tecnalia, Department of Conservation of Natural Resources, Soil Microbial Ecology Group, c/Berreaga 1, E-48160 Derio, Spain.
Instituto BIOFISIKA (CSIC, UPV/EHU), Department of Biochemistry and Molecular Biology, University of the Basque Country, P.O. Box 644, 48080 Bilbao, Spain.
Sci Total Environ. 2019 Jan 10;647:1410-1420. doi: 10.1016/j.scitotenv.2018.08.092. Epub 2018 Aug 8.
The application of sewage sludge as soil amendment is a common agricultural practice. However, wastewater treatment plants, sewage sludge and sewage sludge-amended soils have been reported as hotspots for the appearance and dissemination of antibiotic resistance, driven, among other factors, by selection pressure exerted by co-exposure to antibiotics and heavy metals. To address this threat to environmental and human health, soil samples from a long-term (24 years) field experiment, carried out to study the impact of thermally dried and anaerobically digested sewage sludge (at different doses and frequencies of application) on agricultural soil quality, were investigated for the presence of genes encoding antibiotic resistance (ARGs) and mobile genetic elements (MGEs). Sewage sludge-induced changes in specific soil physicochemical and microbial properties, as indicators of soil quality, were also investigated. The application of sewage sludge increased the total concentration of copper and zinc in amended soils, but without affecting the bioavailability of these metals, possibly due to the high values of soil pH and organic matter content. Soil microbal quality, as reflected by the value of the Soil Quality Index, was higher in sewage sludge-amended soils. Similarly, the application of sewage sludge increased soil microbial activity and biomass, as well as the abundance of ARGs and MGE genes, posing a risk of dissemination of antibiotic resistance. In contrast, the composition of soil prokaryotic communities was not significantly altered by the application of sewage sludge. We found correlation between soil Cu and Zn concentrations and the abundance of ARGs and MGE genes. It was concluded that sewage sludge-derived amendments must be properly treated and managed if they are to be applied to agricultural soil.
将污水污泥作为土壤改良剂应用于农业是一种常见做法。然而，废水处理厂、污水污泥和添加了污泥的土壤已被报道为抗生素抗性出现和传播的热点，这主要是由于抗生素和重金属共同暴露所带来的选择压力。为了解决这一对环境和人类健康的威胁，我们对一项长期（24 年）田间试验的土壤样本进行了研究，该试验旨在研究热干燥和厌氧消化的污水污泥（以不同的剂量和应用频率）对农业土壤质量的影响，以研究土壤中是否存在编码抗生素抗性（ARGs）和移动遗传元件（MGEs）的基因。还研究了污水污泥引起的特定土壤物理化学和微生物特性的变化，这些变化作为土壤质量的指标。污泥的应用增加了改良土壤中铜和锌的总浓度，但并未影响这些金属的生物利用度，这可能是由于土壤 pH 值和有机质含量较高。如土壤质量指数所反映的那样，污泥改良土壤中的土壤微生物质量更高。同样，污泥的应用增加了土壤微生物活性和生物量，以及 ARGs 和 MGE 基因的丰度，从而增加了抗生素抗性传播的风险。相比之下，污泥的应用并未显著改变土壤原核生物群落的组成。我们发现土壤 Cu 和 Zn 浓度与 ARGs 和 MGE 基因的丰度之间存在相关性。研究结果表明，如果要将污水污泥衍生的改良剂应用于农业土壤，则必须对其进行适当的处理和管理。
