利用水生植物原位修复污染水体

在实验围隔系统中，夏季利用凤眼莲、冬季利用耐寒型沉水植物伊乐藻等恢复水生生态系统，研究水生植物对水体氮、磷营养盐、透明度等理化性质的影响.结果表明：水生植物处理围区营养盐水平均显著低于围区对照和大湖水体.最初15 d，凤眼莲生长速度快，覆盖面积从100 m²增加到470 m²；44 d后，覆盖面积达到65％，处理围区的水质最佳，总氮(TN)、铵态氮(NH₄⁺ -N)、亚硝态氮(NO₂^- -N)、高锰酸钾盐指数(COD_Mn)和叶绿素a浓度最低，透明度达到1.7～1.8 m(水底).10月份后，处理围区水体总磷(TP)维持在0.1 mg·L^-1左右.处理围区透明度提高后，伊乐藻逐渐成为优势种(覆盖面积达到总水域的1/3)，在净化水质、维持水质理化性质稳定和提高透明度方面作用显著.表明水生植被恢复可以有效降低水体营养盐，控制浮游植物增长，是改善富营养湖泊水质的重要措施.

In-situ remediation of polluted water body by planting hydrophytes

In an experimental enclosure system, floating plant Eichhornia crassipes was planted in summer and submersed plant Elodea nutalli was planted in winter to reestablish water ecosystem, and to investigate the effects of the hydrophytes on the removal of nitrogen and phosphorus from polluted water body and the improvement of water transparency. The results showed that compared with the control and native pond water, the water body planted with hydrophytes had a low level of nutrients. E. crassipes had a fast growth, with its covered area increased from 100 m2 to 470 m2 in the first 15 days, and to 65% of the water area after 44 days. The total nitrogen, ammonium nitrogen, nitrite nitrogen, CODMn and chlorophyll a decreased to a lower level, and the water transparency increased significantly, reaching to a depth of 1.7-1.8 m (i.e., to the bottom of the pond). After October, the total phosphorus kept on about 0.1 mg L(-1). Due to the increased water transparency, E. nutalli became the dominant species and covered 1/3 of the water area, playing an important role in purifying water quality, keeping water physicochemical properties in good status, and improving water transparency. It was concluded that planting hydrophytes in polluted water body could efficiently reduce its nutrients level and control the overgrowth of algae, being an important way in improving the water quality of eutrophicated water body.