González-Núñez Raquel, Rigol Anna, Vidal Miquel
Departament d'Enginyeria Química i Química Analítica, Universitat de Barcelona, Martí i Franquès 1-11, 3a Planta, 08028, Barcelona, Spain.
Environ Monit Assess. 2017 Apr;189(4):155. doi: 10.1007/s10661-017-5864-z. Epub 2017 Mar 9.
The effect of the addition of industrial by-products (gypsum and calcite) on the leaching of As and metals (Cu, Zn, Ni, Pb and Cd) in a soil contaminated by pyritic minerals was monitored over a period of 6 months at a two-pit pilot plant. The contaminated soil was placed in one pit (non-remediated soil), whereas a mixture of the contaminated soil (80% w/w) with gypsum (10% w/w) and calcite (10% w/w) was placed in the other pit (remediated soil). Soil samples and leachates of the two pits were collected at different times. Moreover, the leaching pattern of major and trace elements in the soil samples was assessed at laboratory level through the application of the pH leaching test. Addition of the by-products led to an increase in initial soil pH from around 2.0 to 7.5, and it also provoked that the concentration of trace elements in soil extracts obtained from the pH leaching test decreased to values lower than quantification limits of inductively coupled plasma optical emission spectrometry and lower than the hazardous waste threshold for soil management. The trace element concentration in the pilot-plant leachates decreased over time in the non-remediated soil, probably due to the formation of more insoluble secondary minerals containing sulphur, but especially decreased in pit of the remediated soil, in agreement with laboratory data. The pH in the remediated soil remained constant over the 6-month period, and the X-ray diffraction analyses confirmed that the phases did not vary over time, thus indicating the efficacy of the addition of the by-products. This finding suggests that soil remediation may be a feasible option for the re-use of non-hazardous industrial by-products.
在一个双坑中试工厂对添加工业副产品（石膏和方解石）对受黄铁矿矿物污染土壤中砷和金属（铜、锌、镍、铅和镉）浸出的影响进行了为期6个月的监测。将受污染土壤置于一个坑中（未修复土壤），而将受污染土壤（80%重量/重量）与石膏（10%重量/重量）和方解石（10%重量/重量）的混合物置于另一个坑中（修复土壤）。在不同时间收集两个坑的土壤样品和渗滤液。此外，通过应用pH浸出试验在实验室水平评估土壤样品中主要和微量元素的浸出模式。副产品的添加导致初始土壤pH值从约2.0增加到7.5，并且还促使从pH浸出试验获得的土壤提取物中微量元素浓度降低到低于电感耦合等离子体发射光谱法定量限的值，并且低于土壤管理的危险废物阈值。中试工厂渗滤液中的微量元素浓度在未修复土壤中随时间降低，这可能是由于形成了更多含硫的难溶次生矿物，但在修复土壤坑中尤其降低，这与实验室数据一致。修复土壤中的pH值在6个月期间保持恒定，X射线衍射分析证实各相随时间没有变化，从而表明添加副产品的有效性。这一发现表明，土壤修复可能是再利用无害工业副产品的一个可行选择。
