Institute of Soil and Water Resources and Environmental Science, Zhejiang University, Hangzhou 310029, China.
J Environ Sci (China). 2009;21(10):1415-23. doi: 10.1016/s1001-0742(08)62434-1.
Constructed wetlands have emerged as a viable option for helping to solve a wide range of water quality problems. However, heavy metals adsorbed by substrates would decrease the growth of plants, impair the functions of wetlands and eventually result in a failure of contaminant removal. Typha latifolia L., tolerant to heavy metals, has been widely used for phytoremediation of Pb/Zn mine tailings under waterlogged conditions. This study examined effects of iron as ferrous sulfate (100 and 500 mg/kg) and lead as lead nitrate (0, 100, 500 and 1000 mg/kg) on phosphorus utilization and microbial community structure in a constructed wetland. Wetland plants (T. latifolia) were grown for 8 weeks in rhizobags filled with a paddy soil under waterlogged conditions. The results showed that both the amount of iron plaque on the roots and phosphorus adsorbed on the plaque decreased with the amount of lead addition. When the ratio of added iron to lead was 1:1, phosphorus utilized by plants was the maximum. Total amount of phospholipids fatty acids (PLFAs) was 23%-59% higher in the rhizosphere soil than in bulk soil. The relative abundance of Gram-negative bacteria, aerobic bacteria, and methane oxidizing bacteria was also higher in the rhizosphere soil than in bulk soil, but opposite was observed for other bacteria and fungi. Based on cluster analysis, microbial communities were mostly controlled by the addition of ferrous sulfate and lead nitrate in rhizosphere and bulk soil, respectively.
人工湿地已成为解决多种水质问题的可行选择。然而，被基质吸附的重金属会降低植物的生长，损害湿地的功能，最终导致污染物去除的失败。耐重金属的香蒲已广泛用于淹水条件下 Pb/Zn 矿山尾矿的植物修复。本研究考察了铁（硫酸亚铁 100 和 500mg/kg）和铅（硝酸铅 0、100、500 和 1000mg/kg）对人工湿地中磷利用和微生物群落结构的影响。湿地植物（香蒲）在充水条件下的根袋中生长了 8 周，根袋中填充了稻田土。结果表明，随着铅添加量的增加，根上铁斑的数量和斑块上吸附的磷都减少了。当添加的铁与铅的比例为 1:1 时，植物利用的磷最多。根际土壤中总磷脂脂肪酸（PLFA）比原状土壤多 23%-59%。根际土壤中革兰氏阴性菌、需氧菌和甲烷氧化菌的相对丰度也高于原状土壤，但其他细菌和真菌则相反。基于聚类分析，根际和原状土壤中微生物群落主要受硫酸亚铁和硝酸铅的添加控制。
