Environmental Sciences Department, Faculty of Science, Alexandria University, Alexandria, Egypt.
Environ Monit Assess. 2012 Mar;184(3):1753-71. doi: 10.1007/s10661-011-2076-9. Epub 2011 May 12.
The concentrations of Cd, Cu, Pb, and Zn in sediments, water, and different plant organs of six aquatic vascular plant species, Ceratophyllum demersum L. Echinochloa pyramidalis (Lam.) Hitchc. & Chase; Eichhornia crassipes (Mart.) Solms-Laub; Myriophyllum spicatum L.; Phragmites australis (Cav.) Trin. ex Steud; and Typha domingensis (Pers.) Poir. ex Steud, growing naturally in the Nile system (Sohag Governorate), were investigated. The aim was to define which species and which plant organs exhibit the greatest accumulation and evaluate whether these species could be usefully employed in biomonitoring and phytoremediation programs. The recorded metals in water samples were above the standard levels of both US Environmental Protection Agency and Egyptian Environmental Affairs Agency except for Pb. The concentrations of heavy metals in water, sediments, and plants possess the same trend: Zn > Cu > Pb > Cd which reflects the biomonitoring potentialities of the investigated plant species. Generally, the variation of heavy element concentrations in water and sediments in relation to site and season, as assessed by two-way repeated measured ANOVA, was significant (p < 0.05). However, insignificant variations were observed in the concentrations of Pb and Cd in sediments in relation to season and of Cu and Zn in relation to site. Results also showed that the selectivity of the heavy elements for the investigated plants varied significantly (p < 0.05) with species variation. The accumulation capability of the investigated species could be arranged according to this pattern: C. demersum > E. crassipes > M. spicatum > E. pyramidalis > T. domingensis > P. australis. On the basis of the element concentrations, roots of all the studied species contain higher concentrations of Cu and Zn than shoots while leaves usually acquire the highest concentrations of Pb. Cd concentrations among different plant organs are comparable except in M. spicatum where the highest Cd concentrations were recorded in the leaves. Our results also demonstrated that all the studied species can accumulate more than 1,450-fold the concentration of the investigated heavy elements in water rendering them of interest for use in phytoremediation studies of polluted waters. Given the absence of systematic water quality monitoring, heavy elements in plants, rather than sediments, provide a cost-effective means for assessing heavy element accumulation in aquatic systems during plant organ lifespan.
对生长在尼罗河系统（索哈杰省）中的六种水生维管束植物（金鱼藻、空心莲子草、凤眼蓝、芦苇、竹叶眼子菜和香蒲）的沉积物、水和不同植物器官中的 Cd、Cu、Pb 和 Zn 浓度进行了研究。目的是确定哪种植物具有最强的积累能力，以及哪种植物器官的积累能力最强，并评估这些物种是否可以用于生物监测和植物修复计划。水样中记录的金属含量高于美国环境保护署和埃及环境事务署的标准水平，除了 Pb 以外。水、沉积物和植物中的重金属浓度具有相同的趋势：Zn > Cu > Pb > Cd，这反映了所研究植物物种的生物监测潜力。一般来说，通过双向重复测量 ANOVA 评估，水和沉积物中重金属浓度的变化与地点和季节有关，这是显著的（p < 0.05）。然而，在沉积物中 Pb 和 Cd 的浓度与季节、Cu 和 Zn 的浓度与地点之间没有观察到明显的变化。结果还表明，重金属对所研究植物的选择性因物种而异而有显著差异（p < 0.05）。根据元素浓度，所研究物种的积累能力可以按照以下模式进行排列：金鱼藻 > 凤眼蓝 > 竹叶眼子菜 > 空心莲子草 > 香蒲 > 芦苇。根据元素浓度，所有研究物种的根比茎叶含有更高浓度的 Cu 和 Zn，而叶片通常含有最高浓度的 Pb。除了竹叶眼子菜，在不同植物器官中 Cd 的浓度可以相互比较，在竹叶眼子菜中叶片的 Cd 浓度最高。我们的研究结果还表明，所有研究物种都可以在水中积累比调查的重金属浓度高 1450 倍以上，这使它们对用于受污染水的植物修复研究具有吸引力。由于缺乏系统的水质监测，植物中的重金属而不是沉积物中的重金属提供了一种经济有效的方法，用于在植物器官寿命期间评估水生系统中重金属的积累。
