天然黏土联合磷肥对农田土壤镉铅污染原位钝化修复效应研究

为研究天然黏土联合磷肥对农田土壤镉铅污染的原位钝化修复效应,在天津市某地开展了田间示范实验,以油麦菜、油菜和萝卜为模式作物,以海泡石、膨润土和磷肥等作为钝化修复材料,研究其对蔬菜可食部位生物量、镉铅含量和土壤中镉铅形态分布的影响,考察其对土壤镉铅污染的原位钝化修复效果.结果表明:磷肥、海泡石/磷肥复配、膨润土/磷肥复配...

In-situ immobilization of cadmium and lead in a contaminated agricultural field by adding natural clays combined with phosphate fertilizer

In-situ immobilization field experiments were carried out in cadmium and lead contaminated agricultural field in Tianjin. Lactuca sativa L, Brassica campestris L and Raphanus sativus were selected as model vegetables. Phosphate fertilizer, natural clays such as sepiolite and bentonite, and the composites of them were employed as immobilization materials for heavy metal pollution. The effects of immobilization materials on the biomass of vegetables, the concentrations of cadmium and lead in the edible parts and the speciation transformation of cadmium and lead were investigated. It was found that the phosphate fertilizer and its composite with sepiolite or bentonite could increase the biomass of vegetables. All the immobilization materials could decrease the cadmium and lead contents in the vegetables in different degrees. The composite of sepiolite and phosphate fertilizer had the best performance, and the contents of cadmium in Lactuca sativa L and Brassica campestris L were below the level of national standard for food safety. All the immobilization treatments could inhibit the bioavailability of heavy metals by reducing the contents of exchangeable fractions and increasing the residual fraction of heavy metals. Therefore the proposals using natural clays combined with phosphate fertilizer were efficient for the in-situ remediation of cadmium and lead contaminated agricultural field.