螯合剂添加对蜈蚣草修复砷污染土壤效果的影响分析

用盆栽试验的方法，研究了3种可生物降解螯合剂谷氨酸二乙酸四钠（GLDA）、甲基甘氨酸二乙酸（MGDA）、乙二胺二琥珀酸（EDDS）和1种传统螯合剂乙二胺四乙酸（EDTA），在不同浓度（0，1.25，2.50，5.00，10.00 mmol/kg）下对蜈蚣草吸收土壤中As的影响。研究表明:4种螯合剂在1.25 mmol/kg时均能显著提高蜈蚣草生物量。EDDS在10 mmol/kg时根际土壤生物有效态As的含量最高，较空白组CK提高了69.2%。GLDA在10.00 mmol/kg时根际土壤As较原土壤降低了28.84%。浓度为5.00 mmol/kg的EDDS处理的蜈蚣草对As的富集系数BCF最高，为7.99，是CK的1.70倍。综合蜈蚣草生物量和对As的BCF值来看，5.00 mmol/kg MGDA地上部分对As积累量最大，其值为2648.65 μg/pot，较CK提高了65.92%。已被广泛应用于修复土壤Cd和Zn领域的新型螯合剂GLDA和MGDA在修复土壤As污染同样具有明显的潜力。

EFFECT OF CHELATING AGENT ON PTERIS VITTATA FOR REMEDIATION OF ARSENIC-CONTAMINATED SOIL

A pot test was conducted to study the effect of different chelating agents on absorption of As in soil by Pteris vittata, which included three biodegradable chelating agents, tetrasodium glutamate diacetate (GLDA), trisodium dicarboxymethylglycine (MGDA), ethylenediamine disuccinic acid (EDDS) and a traditional chelating agent, ethylenediaminetetraacetic acid (EDTA), with dosage ranged of 0~10 mmol/kg. It showed that all of the four chelating agents could significantly increase the biomass of Pteris vittata with the dosage of 1.25 mmol/kg. The bioavailable As content in rhizosphere soil was the highest when using 10 mmol/kg EDDS, which was 69.2% higher than CK. While As in the rhizosphere soil was 28.84% lower than that in the original soil, when the concentration of GLDA was 10.00 mmol/kg. The BCF of As was the highest (7.99), 1.7 times of that of CK, when treated with 5.00 mmol/kg EDDS. Accoding to Pteris vittata biomass and BCF of As, the accumulation of As of the above-ground part of the plant reached the maximum when treating with 5.00 mmol/kg MGDA, as high as 2648.65 μg/pot and 65.92% higher than CK group. Therefore, chelating agents GLDA and MGDA, which had been widely used in the field of soil remediation on Cd and Zn pollution, also had obvious potential for remediation on As contaminated soil.