Calheiros Cristina S C, Rangel António O S S, Castro Paula M L
Escola Superior de Biotecnologia, Universidade Católica Portuguesa, Rua Dr. António Bernardino de Almeida, 4200-072, Porto, Portugal.
Arch Environ Contam Toxicol. 2008 Oct;55(3):404-14. doi: 10.1007/s00244-007-9087-0. Epub 2008 Jan 24.
Toxicity tests were performed to assess the effect of tannery wastewater with different treatment levels on two wetland plants, Phragmites australis and Typha latifolia, which are frequently used in constructed wetlands (CWs) for water treatment, and thus deepen the knowledge on their capacity to withstand the application of industrial wastewater. Trifolium pratense, a plant generally used as an indicator in toxicity tests, was included as a control. End points measured were germination percentage, shoot length, root elongation, and biomass growth of the plants. When tannery effluent, with a low treatment level, was supplied to the wetland plants germination occurred even at effluent concentrations of 100%, whereas germination of T. pratense was completely inhibited, almost invariably, at effluent concentration of 50%. Higher germination levels were achieved when the plants were exposed to effluent originating from the outlet of constructed wetland pilot units, allowing germination of all tested plants, indicating a significant decrease in its toxicity level. Experiments conducted with the same plants using different growing substrata as the germination matrix, namely expanded clay aggregates (Filtralite MR 3-8 and Filtralite NR 3-8) and two types of sand (fine gravel and standard sand) have shown that higher germination levels were achieved in standard sand and that P. australis was the plant species showing higher germination in all cases, reinforcing the robustness of this plant to environmental stress. The phytoextraction potential of P. australis, was evaluated by subjecting the plant to tannery wastewater supplemented with 50 and 150 mg Cr/L. After 6 weeks of exposure, levels up to 4825, 883, and 627 mg Cr/kg were found in the rhizome, shoot, and leaves, respectively, although phytotoxic signs in the plant were evident. This plant might not be considered a chromium hyperacumulator, but the potential to extract and accumulate this metal on its rhizomes is high.
进行了毒性试验，以评估不同处理水平的制革废水对两种湿地植物芦苇和香蒲的影响，这两种植物常用于人工湿地（CWs）进行水处理，从而加深对它们耐受工业废水应用能力的了解。作为对照，纳入了通常用作毒性试验指示植物的红车轴草。所测量的终点指标为植物的发芽率、茎长、根伸长和生物量增长。当低处理水平的制革废水供应给湿地植物时，即使在废水浓度为100%的情况下也会发芽，而红车轴草在废水浓度为50%时几乎总是完全抑制发芽。当植物暴露于人工湿地中试单元出口流出的废水时，发芽水平更高，所有受试植物都能发芽，这表明其毒性水平显著降低。使用不同生长基质作为发芽基质，即膨胀粘土集料（Filtralite MR 3 - 8和Filtralite NR 3 - 8）和两种类型的沙子（细砾石和标准砂），对相同植物进行的实验表明，在标准砂中发芽水平更高，并且在所有情况下芦苇都是发芽率较高的植物物种，这增强了该植物对环境胁迫的耐受性。通过使芦苇接触添加了50和150 mg Cr/L的制革废水来评估其植物提取潜力。暴露6周后，在根茎、茎和叶中分别发现高达4825、883和627 mg Cr/kg的铬含量，尽管植物中出现了明显的植物毒性迹象。这种植物可能不被视为铬超富集植物，但其根茎提取和积累这种金属的潜力很高。
