Comparison of Four Amendments for Arsenic and Cadmium Combined Contaminated Soil

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Comparison of Four Amendments for Arsenic and Cadmium Combined Contaminated Soil Ying Li1 · Jiaqi Wen1 · Pengfei Shen1 · Yu Zhou1 · Jianxiang Shen1 · Jinlin Jiang2 · Xiangji Kong2 · Xueyuan Gu1  Received: 9 June 2020 / Accepted: 14 September 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020

Abstract Arsenic (As) and cadmium (Cd) are common soil pollutants whose opposing geochemical behaviors must be taken into account in the development of cost-effective, environmentally friendly remediation strategies. In this study, a pot experiment with lettuce and a field experiment with wheat were performed to examine the impacts of zeolite, biochar, ­MnO2, zerovalent iron (ZVI) individually and in binary combinations thereof on As–Cd pollution. The results of the pot experiment showed that biochar, ­MnO2 and ZVI had good passivation effects on As and Cd when provided individually, but the effects of a combination of 0.2% ZVI/0.5% biochar or 0.2% ­MnO2/0.5% ZVI were even better. These amendments were further investigated in a field experiment, which confirmed the positive effect of 0.2% M ­ nO2/0.5% ZVI. Therefore, ZVI/biochar and ­MnO2/ZVI mixtures may offer effective solutions to the remediation of farmland soil contaminated with both As and Cd. Keywords  As–Cd · Combined pollution · Stabilization · Immobilization · Soil remediation Heavy metal and metalloid pollution in soils is a serious problem in many countries. In areas of intense mining and smelting, combined pollution with arsenic (As) and cadmium (Cd) is common. Moreover, the high toxicity of these metals and their potential transfer to humans through the food chain are of particular concern (Liu et al. 2010, 2013). Farmland in the vicinity of mining and smelting areas may be contaminated by low to medium levels of both As and Cd. Thus, the remediation of these soils, such as by restricting

Electronic supplementary material  The online version of this article (https​://doi.org/10.1007/s0012​8-020-02995​-7) contains supplementary material, which is available to authorized users.

the mobility of As and Cd, requires economical and environmentally friendly strategies. In soil environments, inorganic As mainly occurs as oxyanions of As(V) and As(III) (arsenate and arsenite, respectively) while Cd is generally present as a divalent cation. Due to their different geochemical properties, the fates of the two metals in soil will differ. For example, soil pH has a negative effect on the mobility of Cd and a positive effect on that of As. Anoxic conditions, such as those caused by soil flooding, may increase the mobility of As via the transformation of As(V) to As(III), whereas the mobility of Cd will be reduced due to the formation of sulfide precipitates (Qiao et al. 2018; Yao et al. 2019). The opposing geochemical fates

* Xueyuan Gu [email protected]

Jinlin Jiang [email protected]

Ying Li [email protected]

Xiangji Kong [email protected]

Jiaqi Wen [email protected]

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State Key Laboratory of Pollution Control and Resource Reuse, School of the Environ