Arsenic hyperaccumulation by aquatic macrophytes in the Taupo Volcanic Zone, New Zealand
Arsenic hyperaccumulation by aquatic macrophytes in the Taupo Volcanic Zone, New Zealand
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DOI：
10.1016/j.envexpbot.2005.08.004
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发表时间：
2006-12-01
影响因子：
5.7
通讯作者：
Clothier, Brent
中科院分区：
文献类型：
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作者：
Robinson, Brett;Kim, Nick;Clothier, Brent
在新西兰陶波火山区（TVZ）的地热活动导致该地区许多土壤、湖泊和河流中砷（As）含量升高（0.01-0.1 mg L-1）。TVZ中的一些水生植物已知积累过量的As。我们从TVZ的沿着环境沃茨、沉积物和土壤中采集了28种水生植物和11种陆生植物。选定的水生物种生长在受控条件下，检查作为吸收，耐受性，易位和净化。184种水生植物中砷含量的几何平均值为125 mg kg（-1）干重，而36种陆生植物中砷含量的几何平均值为< 0.5 mg kg（-1）干重。某些水生物种的砷含量超过1000 mg kg（-1），这是砷超积累的阈值。水生沉积物和沃茨中As的平均浓度分别为38 mg kg（-1）和0.021 mg L-1。我们发现铁和砷之间有很强的正相关性，沿着的几何平均铁浓度为3798 mg kg（-1）。水生植物积累较少的控制条件下相比，植物原位收集。砷并没有从水田芥的淹没部分转移到出水部分。高砷样品在砷含量< 0.01 mg L-1的水中快速释放砷。我们的研究结果是一致的假设，即水生植物的积累发生通过物理化学吸附到植物的表面，促进共沉积的其他吸附物种，如水合铁氧化物。积累似乎独立于任何特定的吸收机制。水生植物罗菜（Rorippa nasturtium-aquaticum（L.）和薄荷属（Mentha spp.）在电视区被当作蔬菜来吃在这些物种中，我们发现各自的As浓度高达138和88毫克公斤（-1）的鲜重的基础上。从地热流入的沃茨中采集的水生植物可能会对人类健康造成风险。(c)2005 Elsevier B. V.保留所有权利。
Geothermal activity in the Taupo Volcanic Zone (TVZ), New Zealand, has resulted in elevated (0.01-0.1 mg L-1) levels of arsenic (As) in many of the region's soils, lakes and rivers. Some aquatic plants in the TVZ are known to accumulate inordinate amounts of As. We sampled 28 species of aquatic macrophytes and 11 terrestrial species from the TVZ along with ambient waters, sediments and soils. Selected aquatic species were grown in controlled conditions to examine As-uptake, tolerance, translocation and depuration. The geometric mean As concentration in 184 aquatic macrophytes was 125 mg kg(-1) dry weight, while the geometric mean As concentration of the 36 terrestrial samples was < 0.5 mg kg(-1) in the above-ground portions. Some aquatic species had > 1000 mg kg(-1) As, the threshold for As hyperaccumulation. The average As concentrations in the aquatic sediments and waters were 38 mg kg(-1) and 0.021 mg L-1. We found a strong and positive correlation between Fe and As, along with a geometric mean Fe concentration of 3798 mg kg(-1). Aquatic macrophytes accumulated less As under controlled conditions compared to plants collected in situ. Arsenic was not translocated from the submerged to emergent portions of watercress. High-As specimens rapidly released As when placed in water containing < 0.01 mg L-1 As. Our results are consistent with the hypothesis that As accumulation by aquatic plants occurs via physicochemical adsorption to the plant's surface, facilitated by co-deposition of other adsorptive species such as hydrated Fe oxides. Accumulation appears independent of any specific As-uptake mechanism. The aquatic plants Rorippa nasturtium-aquaticum (L.) and Mentha spp. are foraged as vegetables in the TVZ. In these species, we found respective As concentrations of up to 138 and 88 mg kg(-1) on a fresh weight basis. Consumption aquatic plants taken from waters with geothermal inflows may present a human health risk. (c) 2005 Elsevier B.V. All rights reserved.