Although heavy-metal biomonitoring in aquatic environments has been traditionally based on chemical analyses, these do not reflect the impact on organisms; because of this, international environmental agencies have proposed the use of biomarkers. In this study Cr, Ni, Cu, Zn and Pb were bio-monitored in different species of aquatic plants using Total Reflection X-Ray Fluorescence (TXRF) spectrometry. The relation between each metal with phytochelatins (PCs) was also assessed in order to establish the use of PCs as biomarkers for water pollution contaminants. Samples of Lemna gibba, Myriophyllum heterophyllum, Arenaria paludicola, Hydrocotyle ranunculoides and Eichhornia crassipes collected in natural aquatic environment were analyzed. The results showed significant differences in metal concentration between species both in shoots and roots: Cr, Ni, Cu and Pb were greater in roots in the majority of samples; the maximum content of Pb (7.92 mg/kg) was found in roots of E. crassipes, Cr (7.54 mg/kg), Ni (5.96 mg/kg) in roots and Zn (64.10 mg/kg) and Cu (60.55 mg/kg) in shoots of H. ranunculoides, which showed the heaviest metal concentration. Glutathione (GSH) and the PCs concentrations were also ascertained. Differences between species and parts of the plants were also found, although the tendency was different as regards elemental concentration. Marked differences were detected in metal absorption and sensitivity to produce PCs of the aquatic plants. Pb was the metal with the least concentration in the plants, but, it was the only element that showed a direct correlation (p < 0.05, r > 0.9) with the PCs induction.

中文翻译：

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全反射 X 射线荧光光谱法多元素分析和水生植物中植物螯合素的测定

尽管水生环境中的重金属生物监测传统上基于化学分析，但这些并不能反映对生物的影响；正因为如此，国际环境机构提出了使用生物标志物的建议。在这项研究中，使用全反射 X 射线荧光 (TXRF) 光谱法对不同种类的水生植物中的 Cr、Ni、Cu、Zn 和 Pb 进行了生物监测。还评估了每种金属与植物螯合素 (PC) 之间的关系，以确定 PC 作为水污染污染物的生物标志物的用途。Lemna gibba , Myriophyllum heterophyllum , Arenaria paludicola , Hydrocotyle ranunculoides和Eichhornia crassipes 的样本对自然水生环境中采集的数据进行了分析。结果表明，不同物种的枝条和根部金属浓度存在显着差异：大多数样品的根部Cr、Ni、Cu和Pb含量较高；E. crassipes根中 Pb（7.92 mg/kg）、Cr（7.54 mg/kg）、Ni（5.96 mg/kg）和 Zn（64.10 mg/kg）和 Cu（60.55 mg）的最大含量/kg) 在H.ranunculoides 的枝条中, 显示出最重的金属浓度。还确定了谷胱甘肽 (GSH) 和 PCs 浓度。还发现了植物物种和部分之间的差异，尽管在元素浓度方面的趋势不同。在金属吸收和水生植物产生 PCs 的敏感性方面检测到显着差异。Pb 是植物中浓度最低的金属，但它是唯一 与 PCs 诱导显示直接相关 ( p  < 0.05, r > 0.9) 的元素。