ABSTRACT

Aquatic macrophytes absorb a number of pollutants from where they are growing and thus, they can be used as a tool for the removal of pollutants from the aquatic ecosystem. Therefore, the aim of this study was to evaluate heavy metals (Hg, Cr, Zn, Cd, and Pb) removal efficiency of Typha latifolia L. from the offshore of Hawassa Lake, Ethiopia. Based on the potential exposure of the lake to different sources of pollutants, six sampling sites were selected, and then T. latifolia and composite plant samples were collected from each sampling site and transported to Addis Ababa Environmental Protection Agency (EPA) laboratory for analysis. The results showed that significantly (P < .05) higher heavy metal concentration was recorded in T. latifolia than in composite plant samples, particularly samples collected from S₂, S_4, and S₅. Moreover, significantly (P < .05) higher heavy metal concentration was found in the root parts of the T, latifolia than its shoot. The concentration of heavy metals recorded in this study has slightly exceeded the level set by the WHO guideline. In addition, medium to very high correlations were recorded for some heavy metal pairs as well as with some physicochemical parameters (e.g. pairs of Zn/Pb, Cd/Pb, EC, and pH with most heavy metals).In conclusion, T. latifolia have shown promising potential for the removal of Zn, Pb and Cd, while composite macrophytes samples for Hg and Cr. The shoot part of T. latifolia has a relatively better capacity to remove Cr, while the root is for Hg, Zn, Cd and Pb. These results indicated the suitability of the plant for phytoremediation, and the usefulness of the technique as an option for improving the water quality of the lake by removing those heavy metals from the lake offshore.

摘要

水生大型植物从它们生长的地方吸收许多污染物，因此，它们可以用作从水生生态系统中去除污染物的工具。因此，本研究的目的是评估埃塞俄比亚哈瓦萨湖近海香蒲的重金属（Hg、Cr、Zn、Cd 和 Pb）去除效率。根据湖泊可能暴露于不同来源的污染物，选择了六个采样点，然后从每个采样点采集宽叶阔叶树和复合植物样品并运送到亚的斯亚贝巴环境保护局（EPA）实验室进行分析。结果表明，显着（P< .05) T. latifolia 中记录的重金属浓度高于复合植物样品，特别是从 S ₂、S ₄和 S ₅采集的样品。此外，显着（P< .05) T, latifolia 根部的重金属浓度高于其枝条。本研究记录的重金属浓度略高于世界卫生组织指南规定的水平。此外，一些重金属对以及一些物理化学参数（例如，与大多数重金属的 Zn/Pb、Cd/Pb、EC 和 pH 值对）具有中到非常高的相关性。总之，T. latifolia已显示出去除 Zn、Pb 和 Cd 的有希望的潜力，而复合大型植物样品可去除 Hg 和 Cr。阔叶树的茎部对Cr的去除能力相对较好，而根部对Hg、Zn、Cd和Pb的去除能力相对较好。这些结果表明该植物适合植物修复，