【作者】 乌云；

【导师】 朝伦巴根； 李畅游；

【作者基本信息】 内蒙古农业大学 ， 农业水土工程， 2011， 博士

【摘要】 由于自然演变和人为活动的双重作用,使得水环境发生了根本性的变化,水环境素质开始下降,打乱和破坏了水生态系统平衡,进而影响了人类的正常生活和生产。湖泊水环境也正遭受着外源输入和内源释放的侵害和污染,已渐渐失去了固有的功能和应有价值。本文针对内蒙古乌梁素海严重富营养化问题,在对其上覆水体和表层沉积物中污染物进行时空变异性剖析的基础上,进一步分析了不同环境因子作用下,上覆水体和沉积物界面间的物质迁移转换规律,建立了考虑沉积物中物质释放的水质数学模型,并对所建模型进行检验和适应性评价。得出如下主要结论:⑴将地质统计学理论与地理信息系统相结合,对乌梁素海富营养化指标、有机污染指标、盐化污染指标、“水华”警示指标进行了时空分析和研究。结果表明,各项污染指标呈现出不同的分布规律和特征,通过实测指标与地表水环境质量标准对比,乌梁素海正遭受着富营养化、盐化、有机等复合污染。⑵通过解析乌梁素海表层沉积物营养元素及重金属元素的空间分布特征。结果显示,表层底泥中总氮和总磷具有相似的空间分布特征,呈现出随水流方向由北到南递减的变化趋势,且在湖泊出口处形成局部高峰区;表层底泥中有机碳含量与水生植物时空分布有很强的相关性;表层底泥Cu、Cd、Pb、Zn、Hg、Cr重金属含量具有南北高,中间低的变异特征,且Cd元素平均含量超过全国土壤质量标准Ⅱ级。⑶通过室内外不同环境因素条件下,上覆水体和表层沉积物中各项污染物质的同步试验和监测,利用回归分析方法,对pH、水温、溶解氧、氧化还原电位、表层沉积物有机质含量变化与沉积物中营养物质释放速率的相关性进行了分析。结果表明,碱性环境和高水温有利于表层沉积物中的营养盐向上覆水体中释放;溶解氧水平和氧化还原电位升高,将降低表层沉积物中营养物质的释放;表层沉积物中有机质含量的增加将提高上覆水体中总氮、氨态氮和总磷浓度;另外,表层沉积物氮磷含量与上覆水体中氮磷浓度呈现出互补的现象,且互补趋势冬季优于夏季;⑷建立了考虑沉积物中营养盐释放的水质数学模型,WASP模型模拟结果揭示了湖泊上覆水体与沉积物间物质迁移转化过程。误差分析表明,相对误差在允许精度以内的模拟结果达到83.33%以上,所建模型具有较好的模拟效果。因此,揭示上覆水体与沉积物物质交换的水质数学模型具有一定的应用价值。更多还原

【Abstract】 Due to the natural evolution and human activities, the composition and status of water environment has undergone fundamentally changes. As a result of this, wetland ecosystems have been affacted by means of contamination from both outer and inner sources.As the lake Wulangshuhai has been seriously entroficated, the spatial and temporal distribution of contaminants within its water body and uper-layer sediments were analyzed. Especially the interactions between the water body and uper-layer sediments by means of contaminant transport were modeled. The results showed that:(1) Combining with the geostatistics theory and GIS, the temporal and spatial distribution of the contaminants were analyzed, including eutrophication indexes, organic matter, and nutrient salts etc. The results showed that the contaminants represented different distribution characteristics and the lake Wuliangsu is at the status of eutrophication, salinity, and organic contamination.(2) The content and the spatial distribution of nutrient salts in the sediments indicated that the total nitrogen and total phosphorus have similar spatial distribution characteristics with a decrease in content with the flow direction. Organic carbon content in the mainly depends on the distribution and density of aquatic plants. Content of heavy metals like Cu, Cd, Pb, Zn, Hg, Cr in the sediments varied spatially, being higher in the northern and southern parts and lower in the center area. The average content of Cd is exceeded to GradeⅡof the national soil quality standards.(3) The field site monitoring and the lab experiment results showed that nutrient salts could release faster from the sediments into the water body at alkaline and higher temperature status, higher dissolved oxygen content and redox potential could reduce the release rate of nutrient salts; and higher organic matter content in the sediments could led to higher concentration of total nitrogen, ammonia nitrogen and total phosphorus in the water body. In one word, the total nitrogen and phosphorus within the sediments the water body were exchanged especially in the summer time.(4) WASP model represented the processes of contaminants transport between the sediments the water body. The results showed that the accuracy is greater than 83.33% between the modeled and measured results.更多还原