红树根系对河口沉积物中重金属入海的控制研究
- 来源：新浪科技 作者：娱记 时间：2008-05-05 21:02:10
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红树根系对河口沉积物中重金属入海的阻滞与控制研究
(环境科学)
厦门第一中学、高三年级、严钦骅
以秋茄为材料研究河口湿地红树对沉积物中重金属迁移的阻滞与控制。用HPLC测定其根系分泌的低分子量有机酸(LMWOAs)，用薄层色谱技术研究LMWOAs对重金属迁移的影响。结果表明：秋茄根系LMWOAs主要为甲酸、丁二酸、苹果酸、柠檬酸和乳酸；重金属在LMWOAs作用下的迁移系数表明：LMWOAs能有效提高重金属的迁移，林内三种重金属的迁移速率为Zn≥Cd>>Pb；对比研究沉积物中重金属含量为林内>林缘>林外，并且与沉积物机械组成、有机质及铁锰含量、沉积动力等因素相关。微粒对光滩中重金属含量影响较大，有机质含量则对林内沉积物重金属含量影响较大。红树能有效影响重金属的理化特征，对重金属海陆迁移有明显的阻滞与控制作用。研究成果为红树林湿地保护、沉积物治理提供了科学的理论支持。
Study on the influence of mangrove rhizosphere ecosystem on heavy metals transportations and control in estuary sediments
(Environment Sciences)
Xiamen No.1 High School, Senior 3, Yan Qinhua
Mangroves is an important inter-tidal habitat which is usually found in tropical and subtropical coasts, and is recognized as playing an important role in sediment reactions that greatly influence the mobility of heavy metals. In this study, the influence of mangrove Kandelia candel (L) Druce on heavy metals transportations and control in estuary mangrove sediments were studied. Root exudates low molecular weight organic acids (LMWOAs) were detected by high performance liquid chromatography (HPLC) and thin layer chromatography were used to study the effect of LMWOAs on heavy metals transportation. The results show that formic, succinic, malic and citric acids were dominant in root exudates LMWOAs. The coefficients of transportation indicate that LMWOAs increase the heavy metals transport in sediment. The transport rate of heavy metals in forest sediments shows the following trends: Zn≥Cd>>Pb. The concentration of heavy metals in different sediments following the trend: forest sediment>forest edge sediment > bare sediment. The heavy metals concentration was influenced by the sediment texture, organic matters, irons and manganese content and sedimentation dynamics. The quantity of clay obviously influences the heavy metals concentration in bare sediment. But for forest sediment, organic matters influence the heavy metals concentration much more. Mangroves’ effect on physical and chemical characteristics of heavy metals and obviously influence on heavy metal transport form terrestrial area to ocean. The Study on the influence of mangrove rhizosphere system on heavy metals transportation and control in estuary mangroves’ sediments will be helpful to provide theory evidence and to pollution control and assessment, improve the conservation of mangrove wetland and sustainable development of coastal ecosystem.
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