CIMAR/CIIMAR - Centro Interdisciplinar de Investigação Marinha e Ambiental, Universidade do Porto, Rua dos Bragas, 289, 4050-123, Porto, Portugal.
Environ Sci Pollut Res Int. 2010 Jul;17(6):1279-86. doi: 10.1007/s11356-010-0307-1. Epub 2010 Mar 10.
The capability of Halimione portulacoides, Spartina maritima, and Sarcocornia fruticosa (halophytes very commonly found in salt marshes from Mediterranean areas) for enhancing remediation of tributyltin (TBT) from estuarine sediments was investigated, using different experimental conditions.
The influence of H. portulacoides on degradation of the butyltin compounds was assessed in two different ways: (1) a 9-month ex situ study carried out in a site of Sado River estuary, center of Portugal, which used polluted sediments collected at other nonvegetated site from the same estuary; and (2) a 12-month laboratorial study, using both plant and sediment collected at a relatively clean site of Cávado River estuary, north of Portugal, the sediment being doped with TBT, DBT, and MBT at the beginning of the experiment. The role of both S. fruticosa and S. maritima on TBT remediation in sediments was evaluated in situ, in salt marshes from Marim channel of Ria Formosa lagoon, south of Portugal, which has large areas colonized by each one of these two plants. For estimation of microbial abundance, total cell counts of sediment samples were enumerated by the DAPI direct count method. Butyltin analyses in sediment were performed using a method previously validated, which consisted of headspace solid-phase micro-extraction combined with gas chromatography-mass spectrometry after in situ ethylation (with tetraethylborate).
Sediments colonized both ex situ and at lab by H. portulacoides displayed TBT levels about 30% lower than those for nonvegetated sediments with identical initial composition, after 9-12 months of plant exposure. In addition, H. portulacoides showed to be able of stimulating bacterial growth in the plant rhizosphere, which probably included degraders of TBT. In the in situ study, which compared the levels of TBT, DBT, and MBT in nonvegetated sediment and in sediments colonized by either S. maritima or S. fruticosa from the same area, TBT and DBT were only detected in nonvegetated sediment, whereas MBT was quantified in most samples.
This work demonstrated that H. portulacoides has potentiality to be used for enhancing TBT remediation in sediments from salted areas. The results observed in situ for S. maritima or S. fruticosa suggested that these two salt marsh plants also favored TBT remediation.
Therefore, the application of halophytes in technologies for TBT remediation in sediments seems to be efficient both in situ and ex situ, cost effective, and nondestructive, despite the fact that they have been rarely used for this purpose so far.
本研究采用不同的实验条件，研究了滨藜（Halimione portulacoides）、盐地碱蓬（Spartina maritima）和海蓬子（Sarcocornia fruticosa）（这些盐沼植物在来自地中海地区的盐沼中非常常见）对河口沉积物中三丁基锡（TBT）修复的增强作用。
滨藜对丁基锡化合物降解的影响通过两种不同的方式进行评估：（1）在葡萄牙中部萨多河口的一个现场进行了为期 9 个月的体外研究，该研究使用了从同一河口的其他无植被地点采集的污染沉积物；（2）在葡萄牙北部卡瓦多河口的一个相对清洁的地点进行了为期 12 个月的实验室研究，该地点在实验开始时就用 TBT、DBT 和 MBT 掺杂了植物和沉积物。在葡萄牙里阿法罗湾马利姆海峡的盐沼中，通过原位实验评估了盐地碱蓬和盐地碱蓬对沉积物中 TBT 修复的作用，这两个地点都有大量的这两种植物。为了估计微生物的丰度，通过 DAPI 直接计数法对沉积物样品的总细胞计数进行了计数。使用先前经过验证的方法对沉积物中的丁基锡进行分析，该方法包括原位乙基化（用四乙基硼酸盐）后顶空固相微萃取与气相色谱-质谱联用。
在暴露于植物 9-12 个月后，与具有相同初始组成的无植被沉积物相比，滨藜在体外和实验室中定殖的沉积物中的 TBT 水平降低了约 30%。此外，滨藜还显示出能够刺激植物根际的细菌生长，其中可能包括 TBT 的降解菌。在原位研究中，比较了无植被沉积物和同一地区盐地碱蓬或盐地碱蓬定殖的沉积物中 TBT、DBT 和 MBT 的水平，结果表明，只有无植被沉积物中检测到 TBT 和 DBT，而大多数样品中都检测到了 MBT。
本研究表明，滨藜具有增强盐渍地区沉积物中 TBT 修复的潜力。在原位观察到的盐地碱蓬或盐地碱蓬的结果表明，这两种盐沼植物也有利于 TBT 的修复。
因此，尽管迄今为止这些盐生植物很少被用于该目的，但在原位和体外应用盐生植物作为 TBT 修复沉积物的技术似乎是有效、经济且无损的。
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