基于农田中试试验的重金属污染原位钝化修复效果研究与评估

Research and Evaluation of Ln-situ Passivation Remediation Effect of Heavy Metal Pollution Based on Pilot Tests on Farmland

当前,受城市及工业化迅猛发展影响,我国耕地数量与质量持续下降,重金属污染问题尤为突出。原位固化技术作为一种绿色低碳技术,可有效限制重金属的可生物利用性,从而提高我国耕地数量与安全利用率。本研究以田间试验为基础,以小麦籽粒中重金属含量为评价标准,对酸改凹凸棒石、凹凸棒石、酸改Fixall药剂和Fixall药剂的剂量及应用条件进行探究。研究结果表明,对于铅、镉和砷,酸改凹凸棒石和酸改Fixall药剂对农田重金属的钝化效果更优,酸改凹凸棒石的最佳添加质量比分别为3%、3%和7%,与对照组相比,小麦籽粒中对应含量下降分别为48.21%、49.81%和25.40%。酸改Fixall药剂对农田重金属的钝化效果最佳添加质量比相同,均为3%,与对照组相比,小麦籽粒中对应含量下降分别为59.76%、46.63%和24.60%。其中,经添加比为3%的酸改Fixall药剂处理后,小麦籽粒中铅元素含量达到《食品安全国家标准食品中污染物限量》(GB 2762-2017)规定的要求,其他重金属含量得到显著降低,对提高我国农田数量可利用性及使用安全率具有广泛的应用前景。

At present,affected by the rapid development of cities and industrialization,the quantity and quality of cultivated land in China continue to decline,and the problem of heavy metal pollution is particularly prominent.As a green and low-carbon technology,in-situ solidification technology can effectively limit the bioavailability of heavy metals,so as to improve the number and safe utilization of cultivated land in China.Based on field experiments and taking the content of heavy metals in wheat grains as the evaluation index,this study explored the dosage and application conditions of acid modified attapulgite,attapulgite,acid modified Fixall and Fixall.The results showed that for lead,cadmium and arsenic,the passivation effect of acid modified attapulgite and acid modified Fixall on heavy metals in farmland was better.The optimal mass ratio of acid modified attapulgite was 3%,3% and 7%respectively.Compared with the control group,the corresponding content in wheat grains decreased by 48.21%,49.81% and 25.40% respectively.Acid modified Fixall has the best passivation effect on heavy metals in farmland,with the same mass ratio of 3%.Compared with the control group,the corresponding content in wheat grains decreased by 59.76%,46.63% and 24.60% respectively.Among them,after the treatment of acid modified Fixall with an addition ratio of 3%,the content of lead in wheat grains meets the requirements of the national standard for food safety,limits of pollutants in food(GB 2762-2017),and the content of other heavy metals has been significantly reduced,which has a broad application prospect for improving the availability and safety of farmland in China.