Huang Jianwei W, Poynton Charissa Y, Kochian Leon V, Elless Mark P
Edenspace Systems Corporation, Dulles, Virginia 20151, USA.
Environ Sci Technol. 2004 Jun 15;38(12):3412-7. doi: 10.1021/es0351645.
Arsenic contamination of drinking water poses serious health risks to millions of people worldwide. Current technologies used to clean arsenic-contaminated water have significant drawbacks, such as high cost and generation of large volumes of toxic waste. In this study, we investigated the potential of using recently identified arsenic-hyperaccumulating ferns to remove arsenic from drinking water. Hydroponically cultivated, two arsenic-hyperaccumulating fern species (Pteris vittata and Pteris cretica cv. Mayii) and a nonaccumulating fern species (Nephrolepis exaltata) were suspended in water containing 73As-labeled arsenic with initial arsenic concentrations ranging from 20 to 500 microg L(-1). The efficiency of arsenic phytofiltration by these fern species was determined by continuously monitoring the depletion of 73As-labeled arsenic concentration in the water. With an initial water arsenic concentration of 200 microg L(-1), P. vittata reduced the arsenic concentration by 98.6% to 2.8 microg L(-1) in 24 h. When the initial water arsenic was 20 microg L(-1), P. vittata reduced the arsenic concentration to 7.2 microg L(-1) in 6 h and to 0.4 microg L(-1) in 24 h. At similar plant ages, both P. vittata and P. cretica had similar arsenic phytofiltration efficiency and were able to rapidly remove arsenic from water to achieve arsenic levels below the new drinking water limit of 10 microg L(-1). However, N. exaltata failed to reduce water arsenic to achieve the limit under the same experimental conditions. The significantly higher efficiency of arsenic phytofiltration by arsenic-hyperaccumulating fern species is associated with their ability to rapidly translocate absorbed arsenic from roots to shoots. The nonaccumulating fern N. exaltata was unable to translocate the absorbed arsenic to the shoots. Our results demonstrate that the arsenic-phytofiltration technique may provide the basis for a solar-powered hydroponic technique that enables small-scale cleanup of arsenic-contaminated drinking water.
饮用水中的砷污染对全球数百万人的健康构成严重风险。目前用于净化受砷污染水的技术存在重大缺陷，如成本高和产生大量有毒废物。在本研究中，我们调查了利用最近发现的砷超积累蕨类植物从饮用水中去除砷的潜力。将水培种植的两种砷超积累蕨类植物（蜈蚣草和克里特岛凤尾蕨品种Mayii）以及一种非积累蕨类植物（高肾蕨）悬浮在含有73As标记砷的水中，初始砷浓度范围为20至500微克/升。通过连续监测水中73As标记砷浓度的消耗来确定这些蕨类植物对砷的植物过滤效率。初始水砷浓度为200微克/升时，蜈蚣草在24小时内将砷浓度降低了98.6%，降至2.8微克/升。当初始水砷为20微克/升时，蜈蚣草在6小时内将砷浓度降至7.2微克/升，在24小时内降至0.4微克/升。在相似的植物年龄下，蜈蚣草和克里特岛凤尾蕨具有相似的砷植物过滤效率，并且能够迅速从水中去除砷，使砷含量降至新的饮用水限值10微克/升以下。然而，在相同实验条件下，高肾蕨未能将水中的砷降低到限值以下。砷超积累蕨类植物显著更高的砷植物过滤效率与其将吸收的砷从根部快速转运到地上部分的能力有关。非积累蕨类植物高肾蕨无法将吸收的砷转运到地上部分。我们的结果表明，砷植物过滤技术可能为太阳能水培技术提供基础，该技术能够小规模净化受砷污染的饮用水。
