以重金属Zn、Fe为研究对象,选取长风公园内的银锄湖和华东师范大学内的丽娃河的沉积物,通过室内模拟水生植物根际泌氧的周期性变化,研究4种不同氧化还原条件:好氧(+O)、厌氧(-O)、好氧后厌氧(+O→-O)和高度厌氧(--O)对沉积物中重金属迁移转化的影响.结果表明,与厌氧处理相比,好氧处理下银锄湖沉积物中可氧化态Fe比例由5.53%下降至4.60%,可还原态Fe比例由13.77%上升至16.20%,残渣态Fe比例由81.08%上升至83.49%,而且Fe向上清液中的释放量减少;弱酸提取态Zn比例由30.14%下降至29.16%,可还原态Zn比例由25.40%下降至23.90%,可氧化态Zn比例由35.73%下降至32.72%,残渣态Zn比例由32.73%上升至35.92%,最终使得上清液中Zn的含量较低.相关性分析结果表明沉积物中可氧化态和可还原态Fe、Zn存在相关性.本研究将对城市富营养化水体生态恢复过程中的风险分析及评价提供科学依据,
The sediments from Yinchu Lake and Liwa River were studied for the effects of redox changes on Zn and Fe transformation. A simulated experiment was conducted with 4 different redox treatments:aerobic (+O), anaerobic (-O), aerobic then anaerobic (+O→-O) and extensively anaerobic (--O). Compared with anaerobic condition (-O), percentage of oxidizable Fe decreased from 5.53% to 4.60% in the sediment from Yinchu Lake under aerobic condition, while reducible and residual Fe increased from 13.77% to 16.20% and from 81.08% to 83.49%, respectively. Furthermore, the concentration of Fe release in the supernatant was decreased. Percentage of Zn in acid extractable, reducible and FeMn oxides fraction were respectively declined from 30.14% to 29.16%, from 25.40% to 23.90% and from 35.73% to 32.72% in the sediment from Yinchu Lake. However, Zn in residual fraction rose from 32.73% to 35.92% after treated with oxygenenation, which decreased the concentration of Zn release in the supernatant. It indicated that Fe and Zn in FeMn oxides fraction and organic matter fraction had good corrections with each other. Our study would provide scientific basis for risk analysis and evalution on eutrophicated urban river in the process of ecological restoration.