土壤重金属钝化效果评估——基于大田试验的研究

采用野外大田试验,研究了钙镁磷肥(Calcium-magnesia phosphate fertilizer)、麦饭石(Medical stone)、氧化铁吸附剂(Ferric oxide adsorbent)、氧化铝复合材料(Alumina composite)、植物型有机肥(Plant-based organic fertilizer)、牛粪(Cow dung)、骨炭(Bone char)对某地重金属污染农田的钝化修复效果,并利用动态加权评估方法评估了这几种钝化材料的综合适用性。试验结果表明:几种材料对土壤pH影响均较小,钙镁磷肥、麦饭石微量提高了土壤pH,与对照组相比分别增加0.68和0.74个单位;施加植物型有机肥、牛粪和骨炭提高了土壤有机质含量,与对照组相比分别增加了3.19、2.64 g·kg~(-1)和1.17 g·kg~(-1)(10.04%、8.31%和3.68%)。几种材料在0.6%的投加量下,除植物型有机肥外均有较好钝化效果,土壤有效态镉降低18%以上,且显著减少糙米中镉蓄积量(0.062～0.087mg·kg~(-1)),低于国家食品安全标准限值。为综合评估几种材料的效果及适用性,以土壤重金属有效态含量、糙米镉含量、修复成本和产量为指标构建动态加权函数综合评估模型,评估结果表明,钙镁磷肥的综合修复效果最好,其次为骨炭和植物型有机肥。

Evaluation of the effect of heavy metal immobilization remediation-field experiment study

Based on field experiments, the remediation effect of several immobilization materials was studied, including calcium-magnesia phosphate fertilizer(CMP), medical stone(MS), ferric oxide adsorbent(FA), alumina composite(AC), plant-based organic fertilizer (POF), cow dung(CD)and bone char(BC). The dynamic weighted comprehensive model was established to assess the comprehensive remediation effects. The results demonstrated that the pH of the soil was slightly influenced by applying these materials, increasing by 0.68 and 0.74 units under CMP and MS treatments, respectively. The application of POF, CD and BC increased the soil organic matter content by 3.19, 2.64 g·kg^-1 and 1.17 g·kg^-1(10.04%, 8.31% and 3.68%)compared with the control check, respectively. Under the dosage of 0.6%, almost all materials showed good immobilization effects, the immobilization efficiency of all materials except POF exceed 18%, and the cadmium content of brown rice was significantly reduced(0.062 to 0.087 mg·kg^-1), which was lower than the National Food Safety Standard of 0.2 mg·kg^-1. The calculation results of the dynamic weighted comprehensive evaluation method showed that CMP was the most applicable immobilization material in this study, BC and POF come second.