地球与环境

文章摘要

3种复合铁基钝化剂对黔西南高砷土壤的修复效果研究

Remediation Effects of Three Complex Iron-based Passivators on High Arsenic Soil in Southwestern Guizhou

投稿时间：2021-04-08 修订日期：2021-12-02

DOI：10.14050/j.cnki.1672-9250.2022.50.022

英文关键词: southwestern Guizhou complex iron-based passivators high arsenic soil rice remediation

基金项目:国家重点研发计划项目（2018YFD0800602）；国家自然科学基金委员会-贵州省人民政府喀斯特科学研究中心项目（U1612442）。

作者	单位	E-mail
吴梅^1,2, 李社红¹, 廖杰^1,2, 薛利利^1,3, 胡锋^1,2, 杨启豪⁴, 赵振杰^1,5	1. 中国科学院地球化学研究所环境地球化学国家重点实验室, 贵阳 550081 2. 中国科学院大学, 北京 100049 3. 盐城工学院环境科学与工程学院, 江苏盐城 224001 4. 佛山市铁人环保科技有限公司, 广东佛山 528000 5. 贵州医科大学环境污染与疾病监控教育部重点实验室, 贵阳 550025	lishehong@vip.gyig.ac.cn

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中文摘要:

为研究不同复合铁基钝化剂对黔西南高砷（As）土壤修复效果，筛选出钝化土壤砷和抑制水稻籽粒砷富集效果较好的复合铁基钝化剂，以期为黔西南高砷背景土壤的修复和管理提供科学依据。本文以黔西南某矿区耕地高砷土壤为研究对象进行水稻盆栽实验，分析了3种市售复合铁基钝化剂（复合型铁基生物炭（A）、铁基生物炭（B）和铁基腐殖酸钾（C））在不同用量（0.67 g/kg、1.34 g/kg、2.68 g/kg、5.36 g/kg）下土壤有效态砷、土壤中砷的各种结合态以及水稻籽粒砷含量的变化。结果表明，三种复合铁基钝化剂的施加可不同程度的提高土壤pH和钝化土壤砷，其中钝化剂C在5.36 g/kg施用量下效果最好，钝化率为26.2%；各处理均使土壤砷的赋存形态发生一定的改变，均不同程度的降低了非专性吸附态、专性吸附态及无定形和弱结晶铁铝氧化物结合态的砷，其中钝化剂A和B主要是向结晶铁铝氧化物结合态砷转变，C处理主要向残渣态砷转变；各处理均显著抑制了水稻精米砷含量，相比对照组，复合钝化剂A在1.34 g/kg施用量下大米对As的富集作用最弱，降低率为48.6%；因为土壤砷钝化率不能完全表征水稻对砷的富集能力，其不宜作为土壤砷修复的唯一考察指标，因此土壤修复评估时应综合考虑土壤钝化率及水稻籽粒对砷累积的综合影响。

英文摘要:

This research aimed to study the effects of different composite iron-based passivators on the remediation of high arsenic (As) soil and select the most appropriate technology with better effects on passivating arsenic in soil and inhibiting arsenic accumulation in rice grains so that provided scientific basis for the high arsenic soil remediation and management in the southwest Guizhou Province. The rice pot experiments of three commercially available composite iron-based passivators (composite iron-based biochar (A), iron-based biochar (B) and iron potassium-based humic acid (C)) remediation effects on the high arsenic soil from southwestern Guizhou were carried out, which including the changes of available arsenic and species in soil and arsenic content in rice grains under different dosages (0.67 g/kg, 1.34 g/kg, 2.68 g/kg, 5.36 g/kg). The results show that the three composite iron-based passivators can increase soil pH and passivate soil arsenic in different degrees. The passivation rate reached 26.2% when using the passivator C at the dosage of 5.36 g/kg. Each treatment changed the occurrence of soil arsenic and reduced the non-obligate adsorbed As, obligate adsorbed As and amorphous and weakly crystalline Fe/Al oxide bound state As to varying degrees, for passivation agent A and B, they mainly changed As to crystalline Fe/Al oxide bound state, for C treatment, it mainly changed As to residual form. Each treatment significantly inhibited the arsenic content in polished rice. Compared with the control, the reduction rate of rice arsenic reached 48.6% when compound passivator A at the dosage of 1.34 g/kg. Because the soil arsenic passivation rate can't fully characterize the rice's accumulation capacity, it should’ be used as the only inspection index for soil arsenic remediation. Therefore, the soil passivation rate and the influence on arsenic accumulation in rice grains should be comprehensively considered when evaluating different soil remediation techniques.

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