College of Environment, Zhejiang University of Technology, Hangzhou, 310032, China.
College of Environment, Zhejiang University of Technology, Hangzhou, 310032, China.
Ecotoxicol Environ Saf. 2020 Mar 15;191:110185. doi: 10.1016/j.ecoenv.2020.110185. Epub 2020 Jan 24.
Landscaping of sludge is a kind of recycling disposal, but the potential heavy metal risks limit its application. In this paper, the sludge soil was remediated by ryegrass, and the effect of ethylene diamine tetraacetic acid (EDTA) was studied through pot experiments. Italian ryegrass was planted in the sludge soil treated with six gradients concentrations of 0, 1, 2, 3, 4, 5 mmol kg of EDTA, and the planting conditions were kept the same. After 45 days of planting, compared with the control group (without EDTA treated), the application of 1-5 mmol kg EDTA decreased ryegrass biomass by 2-43%, reduced soil pH value by 0.21-0.34 unit, and reduced 4.1-9.7% capacity of exchange cation, but increased 1.4-8.6% soil organic matter. After growing ryegrass, the contents of heavy metals decreased by 10% for Cu, 15% for Zn, 6% for Ni, 14% for Cd and 44% for Pb; and after spraying EDTA decreased again by 33% for Cu, 31% for Zn, 56% for Ni, 24% for Cd, and 68% for Pb. In ryegrass, the uptake heavy metals were enhanced, and bio-concentration factor of Cu, Zn, Ni, Cd, and Pb of EDTA treated groups were 1.9, 1.6, 4.1, 2.7, and 4.8 times of the control group, respectively. However, EDTA only significantly increased transfer factor values of Cu and Zn, and made bio-extraction factor value of Cu greater than 1. The remediation factor values were used to comprehensive assess accumulation capacity of heavy metals by ryegrass under EDTA treating, and they ordered in Zn > Cu > Ni > Cd > Pb, and the best dose was 2 mmol kg EDTA. Prediction models for bio-concentration factor were established by using stepwise multiple linear regression, explaining 94.9-99.3% of the corresponding elements with soil organic matter, EDTA dosage, and/or pH value (p < 0.005). This paper provided effective heavy metals remediation data for municipal sludge landscape and the prediction models.
土地开垦是一种回收处理方法，但潜在的重金属风险限制了其应用。本文通过盆栽实验研究了乙二胺四乙酸（EDTA）对黑麦草修复污泥土壤的效果。将意大利黑麦草种植在 0、1、2、3、4、5mmolkg 的 EDTA 梯度浓度处理的污泥土壤中，并保持相同的种植条件。种植 45 天后，与对照组（未用 EDTA 处理）相比，应用 1-5mmolkg EDTA 使黑麦草生物量减少了 2-43%，降低了土壤 pH 值 0.21-0.34 个单位，减少了 4.1-9.7%的交换阳离子能力，但增加了 1.4-8.6%的土壤有机质。种植黑麦草后，铜、锌、镍、镉和铅的含量分别降低了 10%、15%、6%、14%和 44%；再用 EDTA 喷洒后，铜、锌、镍、镉和铅的含量又分别降低了 33%、31%、56%、24%和 68%。黑麦草对重金属的吸收增强，EDTA 处理组的铜、锌、镍、镉和铅的生物浓缩系数分别是对照组的 1.9、1.6、4.1、2.7 和 4.8 倍。然而，EDTA 仅显著增加了铜和锌的转移因子值，使铜的生物萃取因子值大于 1。修复因子值用于综合评估 EDTA 处理下黑麦草对重金属的积累能力，其顺序为 Zn>Cu>Ni>Cd>Pb，最佳剂量为 2mmolkg EDTA。采用逐步多元线性回归建立了生物浓缩系数的预测模型，用土壤有机质、EDTA 用量和/或 pH 值解释了相应元素的 94.9-99.3%（p<0.005）。本文为城市污泥景观和预测模型提供了有效的重金属修复数据。
