海泡石及其复配原位修复镉污染稻田

In-situ remediation of Cd polluted paddy soil using sepiolite and combined amendments

以天然黏土海泡石作为钝化材料,并分别与磷肥、生物炭和硅肥复配,在湖南某镉污染的酸性水稻田进行原位修复示范实验,考察海泡石及其复配对稻谷产量、糙米镉含量及土壤中镉的有效态含量及形态分布变化用以表征修复效果;研究了海泡石及其复配对土壤pH、土壤碱解氮、有效磷含量以表征其对土壤环境质量的影响,并对各项理化指标之间的相关性进行分析。结果表明,田间示范条件下海泡石及其复配均降低了土壤中镉的生物有效性,明显降低了糙米中镉含量。其中海泡石磷肥复配和海泡石硅肥复配处理后,糙米镉含量最大降幅约为72.7%,分别降低至0.33和0.34 mg/kg。海泡石及其复配处理均能不同程度增加土壤中碱解氮及有效磷含量,对于作物生长有益。综合总体表现,海泡石磷肥复配、海泡石硅肥复配可被推荐作为镉污染酸性稻田的原位钝化修复材料,具有推广应用的潜力。

In-situ field scale remediation of Cd polluted paddy soil using sepiolite combined with biochar,phosphate and liquid silicon was conducted to investigate the remediation effects. The effect of combined amendments on grain yields,Cd concentration in brown rice,available Cd contents in soil,pH values of soil,hydrolysable nitrogen and available phosphorus in soils were studied. Results showed that the application of sepiolite and combined amendments could increase soil pH,reduce the bioavailability of Cd in soil and Cd concentration in brown rice. The application of sepiolite/phosphate and sepiolite/liquid silicon significantly decreased Cd accumulation in brown rice by contents of 72. 7%,and Cd concentrations in brown rice were reduced to 0. 33 and0. 34 mg/kg,respectively. Sepiolite and combined amendments increased hydrolysable nitrogen and available phosphorus contents in soil by different contents. Based on the analyses of remediation effects,sepiolite and combined amendments can be recommended as immobilization agents for Cd polluted acid paddy soil.