Faculty of Agriculture Food and Natural Resources, The University of Sydney, Sydney, NSW 2006, Australia.
Environ Sci Pollut Res Int. 2012 Sep;19(8):3506-15. doi: 10.1007/s11356-012-0910-4. Epub 2012 Apr 22.
This field study investigated the phytoremediation potential of two arsenic (As) hyperaccumulating fern species, Pityrogramma calomelanos var. austroamericana and Pteris vittata over 27-month duration at a disused As-contaminated cattle-dip site located at Wollongbar, NSW, Australia. Ferns planted in January 2009 were harvested following 10, 22 and 27 months of growth. A detailed soil sampling was undertaken in June 2009 (initial, n = 42 per plot) and limited sampling in April 2011 (after 27 months, n = 15 per plot) to measure total and phosphate-extractable As concentrations in soil at 0 - 20-, 20 - 40- and 40 - 60-cm depths. The choice of the limited number of samples was considered sufficient to estimate the changes in soil As concentration following phytoremediation based on a geostatistical model. The average frond dry biomass, As concentration and As uptake were significantly (P < 0.001 - 0.05) greater in P. calomelanos var. austroamericana than P. vittata, at all three harvests (1.6 - 4.3, 1.3 - 1.5 and 2.2 - 5.7 times, respectively). After 27-months of growth, P. calomelanos var. austroamericana removed 8,053 mg As (i.e. cumulative over three harvests) in plot B (25.4 kg As ha(-1)) that was 2.65 times higher than that depleted by P. vittata (3,042 mg As in plot A (9.7 kg As ha(-1))). The cumulative frond As uptake data of the two fern species revealed that P. calomelanos var. austroamericana extracted 1.7 - 3.9 % and P. vittata removed 0.53 - 1.5 % of total As from soil at three depths. However, for the surface (0 - 20 cm) and subsurface (40 - 60 cm) layers, the (post-experiment) soil As data indicated that total As concentration in soil was reduced by 49 and 63 % (P < 0.05), respectively, using P. calomelanos var. austroamericana; and 17 and 15 % (P > 0.05), respectively, by P. vittata. Our results show that phytoremediation time based on observed changes in soil As based on limited sampling is not reliable; hence, it is recommended that the frond As uptake should be considered in order to evaluate the phytoremediation efficiency of the two fern species at the experimental site. Using As uptake of the two fern species, we estimate that with P. calomelanos var. austroamericana it would take 55 - 125 years to decrease mean total As content below the ecological investigation level (20 mg kg(-1)) in the surface and subsurface soils, whereas with P. vittata 143 - 412 years would be required to achieve this target.
本田间研究调查了两种砷（As）超积累蕨类植物，即 Pityrogramma calomelanos var. austroamericana 和 Pteris vittata 在澳大利亚新南威尔士州 Wollongbar 一个废弃的砷污染牛浸浴场的 27 个月期间的植物修复潜力。2009 年 1 月种植的蕨类植物在生长 10、22 和 27 个月后收获。2009 年 6 月进行了详细的土壤采样（初始，每个地块 42 个样本），2011 年 4 月进行了有限的采样（27 个月后，每个地块 15 个样本），以测量土壤中总砷和磷酸盐可提取砷浓度在 0-20-、20-40-和 40-60-cm 深度。选择有限数量的样本被认为足以根据地质统计学模型估计植物修复后土壤中砷浓度的变化。在所有三个收获期（1.6-4.3、1.3-1.5 和 2.2-5.7 倍），P. calomelanos var. austroamericana 的蕨类植物的叶片干生物量、砷浓度和砷吸收均显著（P<0.001-0.05）高于 P. vittata。经过 27 个月的生长，P. calomelanos var. austroamericana 在 B 地块（25.4kg As ha-1）中去除了 8053mg As（即三次收获的累积），是 P. vittata 去除量的 2.65 倍（A 地块 3042mg As（9.7kg As ha-1））。两种蕨类植物的累积叶片砷吸收数据表明，P. calomelanos var. austroamericana 从三个深度的土壤中提取了 1.7%-3.9%的总砷，而 P. vittata 则去除了 0.53%-1.5%的总砷。然而，对于表层（0-20cm）和次表层（40-60cm）土壤，（实验后）土壤砷数据表明，使用 P. calomelanos var. austroamericana 后，土壤中总砷浓度分别降低了 49%和 63%（P<0.05）；而 P. vittata 分别降低了 17%和 15%（P>0.05）。我们的结果表明，基于土壤砷变化的观察来确定植物修复时间基于有限的采样不可靠；因此，建议考虑叶片砷吸收，以评估两种蕨类植物在实验点的植物修复效率。根据两种蕨类植物的砷吸收，我们估计，使用 P. calomelanos var. austroamericana，需要 55-125 年才能将表层和次表层土壤中的总砷含量降低到生态调查水平（20mg kg-1）以下，而使用 P. vittata，则需要 143-412 年才能达到这一目标。
