稳定化处理砷污染土壤对3种修复植物的生态效应

为探索某矿区高浓度砷污染土壤的污染控制与生态修复，以粉煤灰、干化污泥、粉碎花生壳、硫酸亚铁（Fe₂SO₄）和磷酸二氢钾（KH₂PO₄）为稳定剂，采用其不同组合对矿区土壤进行稳定化处理，以蜈蚣草、香根草、苎麻为供试植物，研究稳定化处理对土壤中As的形态转化及其对修复植物的生态效应.结果表明，添加不同稳定剂组合处理后，土壤pH值、有机质、阳离子交换量显著增加，增幅分别为：24.4%~29.0%、23.3%~41.1%、17.8%~45.0%；10%粉煤灰、10%干化污泥和1% Fe₂SO₄组合处理对土壤中的As稳定化作用最佳，可交换态As和碳酸盐结合态As含量下降最显著，降幅分别为62.3%、55.3%；添加KH₂PO₄会活化土壤中As，10%粉煤灰、10%干化污泥和1% KH₂PO₄组合处理，土壤中可交换态As、碳酸盐结合态As含量显著增加，增幅分别为26.9%、101.9%.不同稳定剂的组合处理能不同程度的提高3种植物生物量、影响As在植物中的富集、增加植物对As的累积量.3种植物生物量的大小表现为苎麻 > 蜈蚣草 > 香根草.粉煤灰、干化污泥和粉碎花生壳组合处理使蜈蚣草和苎麻地上部分生物量干重增加最显著；粉煤灰、干化污泥、粉碎花生壳、Fe₂SO₄和KH₂PO₄组合处理使香根草地上部分生物量干重增加最显著.10%粉煤灰、10%干化污泥和1% Fe₂SO₄组合处理使蜈蚣草、香根草和苎麻地上部分As含量下降最显著，降幅分别为45.5%、29.5%和53.9%；而10%粉煤灰、10%干化污泥和1% KH₂PO₄的组合处理使蜈蚣草、香根草和苎麻地上部分As含量显著增加，增幅分别为：12.8%、25.2%和62.7%.粉煤灰、干化污泥、粉碎花生壳、Fe₂SO₄和KH₂PO₄组合处理使蜈蚣草、香根草和苎麻地上部分对As的累积量都达到最大值，与对照相比，分别增加了3.7倍，12.8倍和3.3倍.3种植物对As的富集能力和累积量表现为蜈蚣草 > 香根草 > 苎麻.

Ecological effects of stabilization treatment of As contaminated soils on three remediation plants

In order to explore a mining area with high concentration of arsenic contaminated soil pollution control and ecological restoration, the fly ash, dried sludge, crushed peanut shells, ferrous sulfate (Fe₂SO₄) and potassium dihydrogen phosphate (KH₂PO₄) were chosen and combined as stabilizers for stabilization of the contaminated soil, and Pteris vittata L., Vetiveria zizanioides L., Boehmeria nivea L. were used as test plants. The stabilization treatment on the shape transformation of As and its ecological effect on the repair plant were studied. The results showed that after added different stabilizers combined treatment, the pH value, organic matter, cation exchange capacity of the soil increased significantly, with an increase of 24.4%~29.0%、23.3%~41.1%、17.8%~45.0%, respectively. The combination treatment of 10% fly ash, 10% dried sludge and 1% Fe₂SO₄ had the best stabilization effect to the As, and the concentration of exchangeable and carbonate bound As decreased most significantly, by 62.3% and 55.3%; The addition of KH₂PO₄ could activate As in the soil, 10% fly ash, 10% dry sludge and 1% KH₂PO₄ combined treatment could significantly increase the contents of exchangeable and carbonate bound As, with an increase of 26.9% and 101.9% respectively. The combined treatment of different stabilizers could improve three kinds of plant biomass, affect the enrichment of As, and increase the accumulation of As in plants. The biomass of the three plants was Boehmeria nivea > Pteris vittata > Vetiveria zizanioides. The combined treatment of fly ash, dried sludge and crushed peanut shell increased the dry weight of above-ground biomass of Pteris vittata and Boehmeria nivea most significantly, while the combined treatment of fly ash, dried sludge, crushed peanut shell, Fe₂SO₄ and KH₂PO₄ increased the dry weight of above-ground biomass of Vetiveria zizanioides most significantly. The addition of 10% fly ash, 10% dried sludge and 1% Fe₂SO₄ could reduce the above-ground content of As in Pteris vittata, Vetiveria zizanioides and Boehmeria nivea, the largest decline of 45.5%, 29.5% and 53.9% respectively. While added 10% fly ash, 10% dried sludge and 1% KH₂PO₄ made the above-ground content of As increased significantly in the three plants, with an increase of 12.8%, 25.2% and 62.7% respectively. Compared with the control, fly ash, dried sludge, crushed peanut shells, Fe₂SO₄ and KH₂PO₄ combination treatment made Pteris vittata, Vetiveria zizanioides and Boehmeria nivea above-ground accumulation of As reaches the maximum value, increased by 3.7times, 12.8times and 3.3times. The enrichment ability and accumulation amount of As in three plants were Pteris vittata > Vetiveria zizanioides>Boehmeria nivea.