Cao Xinde, Ma Lena Q, Shiralipour Aziz
Department of Soil and Water Science, University of Florida, Gainesville, FL 32611, USA.
Environ Pollut. 2003;126(2):157-67. doi: 10.1016/s0269-7491(03)00208-2.
Chinese brake fern (Pteris vittata L.), an arsenic (As) hyperaccumulator, has shown the potential to remediate As-contaminated soils. This study investigated the effects of soil amendments on the leachability of As from soils and As uptake by Chinese brake fern. The ferns were grown for 12 weeks in a chromated-copper-arsenate (CCA) contaminated soil or in As spiked contaminated (ASC) soil. Soils were treated with phosphate rock, municipal solid waste, or biosolid compost. Phosphate amendments significantly enhanced plant As uptake from the two tested soils with frond As concentrations increasing up to 265% relative to the control. After 12 weeks, plants grown in phosphate-amended soil removed >8% of soil As. Replacement of As by P from the soil binding sites was responsible for the enhanced mobility of As and subsequent increased plant uptake. Compost additions facilitated As uptake from the CCA soil, but decreased As uptake from the ASC soil. Elevated As uptake in the compost-treated CCA soil was related to the increase of soil water-soluble As and As(V) transformation into As(III). Reduced As uptake in the ASC soil may be attributed to As adsorption to the compost. Chinese brake fern took up As mainly from the iron-bound fraction in the CCA soil and from the water-soluble/exchangeable As in the ASC soil. Without ferns for As adsorption, compost and phosphate amendments increased As leaching from the CCA soil, but had decreased leaching with ferns when compared to the control. For the ASC soil, treatments reduced As leaching regardless of fern presence. This study suggest that growing Chinese brake fern in conjunction with phosphate amendments increases the effectiveness of remediating As-contaminated soils, by increasing As uptake and decreasing As leaching.
蜈蚣草（Pteris vittata L.）是一种砷超富集植物，已显示出修复受砷污染土壤的潜力。本研究调查了土壤改良剂对土壤中砷的淋溶性以及蜈蚣草对砷吸收的影响。将蕨类植物在铬酸铜砷酸盐（CCA）污染土壤或加砷污染（ASC）土壤中种植12周。土壤分别用磷矿石、城市固体废物或生物固体堆肥处理。磷改良剂显著提高了植物从两种测试土壤中对砷的吸收，叶片中的砷浓度相对于对照增加了265%。12周后，在磷改良土壤中生长的植物去除了>8%的土壤砷。土壤结合位点上的磷取代砷导致砷的迁移性增强，进而增加了植物对砷的吸收。添加堆肥促进了植物从CCA土壤中吸收砷，但减少了从ASC土壤中吸收砷。堆肥处理的CCA土壤中砷吸收增加与土壤水溶性砷的增加以及As(V)向As(III)的转化有关。ASC土壤中砷吸收减少可能归因于砷吸附到堆肥上。蜈蚣草主要从CCA土壤中的铁结合部分和ASC土壤中的水溶性/可交换砷中吸收砷。在没有蕨类植物吸附砷的情况下，堆肥和磷改良剂增加了CCA土壤中砷的淋溶，但与对照相比，有蕨类植物时淋溶减少。对于ASC土壤，无论有无蕨类植物，处理都减少了砷的淋溶。本研究表明，并添加磷改良剂种植蜈蚣草，通过增加砷的吸收和减少砷的淋溶，提高了修复受砷污染土壤的效果。
