College of Environmental Sciences, Sichuan Agricultural University, Chengdu, 611130, China.
College of Resources, Sichuan Agricultural University, Chengdu, 611130, China.
Environ Sci Pollut Res Int. 2021 Nov;28(43):61811-61824. doi: 10.1007/s11356-021-15037-4. Epub 2021 Jun 29.
Soil washing with environmentally friendly eluents is a rapid remediation technique for farmland polluted by heavy metals. In this study, polyepoxysuccinic acid (PESA), ethylenediamine tetra (methylene phosphonic acid) sodium (EDTMPS), and phosphonyl carboxylic acid copolymer (POCA) were applied to remedy paddy and arid soils polluted by Pb and Cd. At the same time, ethylenediaminetetraacetic acid (EDTA) was used as a control eluent. PESA showed comparable removal of soil Pb and Cd (over 80.0%) with EDTA, and EDTMPS and POCA removed two heavy metals by 35.2-50.3%. For labile fractions, PESA significantly removed Pb by 93.5-96.7% and Cd by 84.9-90.3% in two soils. EDTMPS and POCA removed Pb by 75.5-85.8% in two soils, while they only removed Cd by 11.7-42.2% in paddy soil, and 76.3-81.7% in arid soil. The risks of total heavy metal concentrations were reduced from the high risk to low risk in paddy soil, and to considerable risk in arid soil, while only dropped to considerable or even had no change by EDTMPS and POCA leaching. The risks of the two soils reduced from high to low or considerable level after PESA washing based on labile fraction change, and to considerable or high level after EDTMPS and POCA leaching, respectively. Therefore, PESA is an ecological benefit eluent for remediating the farmland polluted by heavy metals, and the risk assessment based on labile fraction more easily identifies the dynamic change of heavy metal during the washing process.
采用环保洗脱剂进行土壤淋洗是一种快速修复农田重金属污染的方法。本研究采用聚环氧琥珀酸（PESA）、乙二胺四甲叉膦酸钠（EDTMPS）和膦羧基共聚物（POCA）修复 Pb 和 Cd 污染的稻田和旱地土壤，同时以乙二胺四乙酸（EDTA）为对照洗脱剂。PESA 对土壤中 Pb 和 Cd 的去除率与 EDTA 相当（均超过 80.0%），而 EDTMPS 和 POCA 对两种重金属的去除率分别为 35.2-50.3%。对于活性分数，PESA 可显著去除两种土壤中 93.5-96.7%的 Pb 和 84.9-90.3%的 Cd。EDTMPS 和 POCA 可去除两种土壤中 75.5-85.8%的 Pb，而在稻田土壤中仅去除 11.7-42.2%的 Cd，在旱地土壤中仅去除 76.3-81.7%的 Cd。通过淋洗洗脱，两种土壤中总重金属浓度的风险从高风险降至低风险，在旱地土壤中降至相当大的风险，而 EDTMPS 和 POCA 淋洗后仅降至相当大或甚至没有变化。基于活性分数的变化，淋洗后 PESA 可降低两种土壤的风险，从高风险降至低风险或相当大风险，而 EDTMPS 和 POCA 淋洗后，风险分别降至相当大或高风险。因此，PESA 是一种修复重金属污染农田的生态效益洗脱剂，基于活性分数的风险评估更容易识别重金属在洗脱过程中的动态变化。
