长江口滨岸微量金属生物有效性的时空变化及影响机制

On the coastal and estuarine region, processes of land and sea are very strong, and there has intensive human activities, so its environmental problem is serious. In this project, the content, speciation and bioavailability of trace (heavy) metals (Zn, Cu, Pb,) in intertidal sediments of the Yangtze estuarine and coastal zone, were mainly studied. Results show that, trace metals, especially heavy metals such as Zn, Cu and Pb are markedly accumulated in sediments, the heavy metal contaminations and its biological effects in the Yangtze estuary can't be overlooked. Characteristics of the heavy metal distribution and speciation are controlled by the coastal land using and sewage discharge. Contents of total heavy metals and non-residual form heavy metals are obviously higher at Shidongkou, Bailonggang and Wusongkou sites, which is located near the sewage outlet or Huangpu River estuary, than those at Chongming and Donghai stations which is far from sewage effluent, midtown city and industrial district. .The active heavy metals (exchangeable, carbonate bounded, Fe/Mn oxides bounded, and Organic forms) in intertidal sediments were extracted by Tessier method, bioavailable metals in sediments were researched by diluted HCl and DTPA methods. The bioavailability of heavy metals in intertidal sediments was discussed. In generally, the bioavailability of heavy metals follows the sequence: Shidongkou > Bailonggang > Wusongkou > Donghai > Chongming. Also, processes of adsorption/desorption and accumulation and release of heavy metal between the sediment and water interface were investigated by field monitoring and simulated experiments. The pH and salinity are dominated factor to affect the biogeochemistrical behavior of heavy metals in intertidal sediments. .In addition, Distribution and forms of the inorganic nitrogen (N) and phosphorus (P) in intertidal water and sediments were also be researched at this present study, which is closely correlated with heavy metals. Finally, according to the field survey and the present study, Problems of the Yangtze estuarine and coastal resources and environment such as contamination, excessive inning etc., were analyzed, and the regulative countermeasures in the study area were discussed and suggested. In short, the present study enriched the environmental geochemistry of trace metals, and provided basal information for enlivenment protection and sustainable development on the Yangtze estuarine and coastal area..

选择具有典型陆海作用的长江口滨岸带为研究地区，通过沉积物-水-生物系统中微量金属元素分布、形态、迁移转化等生物地球化学行为研究，揭示环境中金属生物有效性的时空变化规律，探讨环境介质条件、沉积物有机无机组分及水动力条件等对金属生物有效性的影响机制，评价和预测河口滨岸环境质量，丰富和发展环境生物地球化学内容，为河口滨岸地区的生态环境保护提供科学依据。