College of Natural Resources and Environment, Northwest A&F University, Yangling, 712100, People's Republic of China.
State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling, 712100, People's Republic of China.
Environ Sci Pollut Res Int. 2019 May;26(13):13041-13053. doi: 10.1007/s11356-019-04786-y. Epub 2019 Mar 20.
Chromium (Cr) is one of the most common metal pollutants and has thus attracted considerable attention. In this study, we investigated the potential use of biogas solid residue (BSR) from anaerobic digestion as an effective amendment to decrease the bioavailability of Cr in Cr(VI)-polluted soil using pot experiments. Compared to the no-addition treatment, the addition of BSR (treatments-50, 100, and 150 g kg soil) increased the soil nutrient levels, microbial diversity and activities, and decreased the redox potential (Eh). BSR treatment of Cr(VI)-contaminated soil caused a reduction in soil Cr(VI) concentration (16.6-52.1%) and the exchangeable Cr proportion (15.2-52.4%), thereby decreasing the available Cr for uptake by plants. BSR treatments resulted in a reduction in the Cr contents of the roots and aboveground biomass of pakchoi plants. The Cr(VI) content in treated soils decreased with increasing BSR addition, with 150 g kg being the most efficient application. The relative abundance of Cr-reducing groups, such as Pseudomonas, Microbacterium, and Bacillus, increased with the increase in BSR application. The enhancement of soil Cr(VI) immobilization by the addition of the BSR was mostly attributed to the simultaneous effect of organic matter addition, stimulation of microorganisms, and reduced Eh value. Organic matter contributed more to the variation in Cr. The presence of BSR decreased the bioavailability of Cr in the soil and, therefore, lowered the potential mobilization of Cr(VI) from the soils. Our results demonstrated that BSR application may offer a potentially promising solution for enhancing agricultural production in Cr-contaminated soils.
铬（Cr）是最常见的金属污染物之一，因此引起了相当大的关注。在这项研究中，我们通过盆栽实验研究了利用沼气固体残留物（BSR）作为有效改良剂来降低 Cr（VI）污染土壤中 Cr 生物有效性的潜力。与不添加处理相比，添加 BSR（处理-50、100 和 150 g kg 土壤）增加了土壤养分水平、微生物多样性和活性，降低了氧化还原电位（Eh）。BSR 处理 Cr（VI）污染土壤导致土壤 Cr（VI）浓度（16.6-52.1%）和可交换 Cr 比例（15.2-52.4%）降低，从而降低了植物吸收的可用 Cr。BSR 处理降低了白菜植物根系和地上部生物量的 Cr 含量。处理土壤中 Cr（VI）含量随 BSR 添加量的增加而降低，150 g kg 时效果最佳。随着 BSR 添加量的增加，Cr 还原菌属（如假单胞菌、微杆菌和芽孢杆菌）的相对丰度增加。BSR 的添加增强了土壤 Cr（VI）的固定，这主要归因于有机质的添加、微生物的刺激和 Eh 值的降低的协同作用。有机质对 Cr 的变化贡献更大。BSR 的存在降低了土壤中 Cr 的生物有效性，从而降低了 Cr（VI）从土壤中潜在的迁移能力。我们的结果表明，BSR 的应用可能为受 Cr 污染的土壤中提高农业生产提供一种有前途的解决方案。
