【作者】 胡春华；

【导师】 周文斌；

【作者基本信息】 南昌大学 ， 环境工程， 2010， 博士

【摘要】 在经济社会快速发展的同时,水资源需求量的缺乏和水环境问题变得越来越严峻,严重制约了世界经济的发展。解决水资源与水环境问题成为21世纪全球资源环境的首要问题。当前,全球水资源和水环境问题日益突出,其中人类驱动因素对其的影响不断加剧。为保护日益紧缺的水资源,必须对湖泊水环境特征及其演化进行系统全面的研究,为水资源的保护和管理提供科学的理论依据。近年来,鄱阳湖水域面积逐年缩少,水土流失严重致使河道和湖底淤积,河床和湖床抬高,从而导致鄱阳湖调蓄洪水的能力大大降低,湖区洪涝灾害发生越来越频繁,呈逐渐加重的趋势。不良的农业生产和土地利用方式、日益严重的大气污染以及农药化肥的大量施用,使入湖的营养物质(如氮、磷等)和POPs输入量增大,鄱阳湖水环境日益恶化。本文在国际科技合作项目“鄱阳湖区水环境及生物多样性研究”、国家自然科学基金“鄱阳湖边缘深水区同位素水文学研究”和江西省经济社会发展重大课题“鄱阳湖生态环境保护和资源综合开发利用研究”的基础上,以鄱阳湖为例,对流域内水化学及同位素水文学、水质特性、水文特性和水环境演化驱动因素及趋势等问题进行研究,揭示鄱阳湖的水化学时空分布特征、水循环特征和同位素水文学特征；分析鄱阳湖湖区及五条主要入湖河流水环境水质状况,并对其水环境功能进行评价；分析边缘深水区氮、磷营养盐的特征及季节变化规律、污染物的来源及运移机制；从自然、人文因素出发探究鄱阳湖流域水环境演化的驱动因素及鄱阳湖流域未来水环境的演化,并为鄱阳湖流域可持续发展提供可行性措施。得出如下主要结论：鄱阳湖流域pH属微酸性至弱碱性,具有较大的缓冲能力；电导率(EC)均低于世界河流EC平均值；鄱阳湖湖区矿化度平均值为75.50mg／L；鄱阳湖湖区水体整体上硬度分布为湖中总硬度较低,各入湖口总硬度较高。鄱阳湖水化学类型总体上以CⅠCa型为主,其次是CⅠNa型,极少部分出现CⅡCa型水；流域水体阳离子主要以Ca2+为主,占总阳离子总当量浓度的55.0%以上,阴离子以HCO3-、SO42-为主。鄱阳湖流域水体中硅酸盐的风化作用对鄱阳湖流域水体化学组成起着主要的控制作用,周边河流(以赣江北支入湖口为例)中的87Sr／86Sr明显高于湖区,但中央深水区又呈偏高的态势,且边缘区87Sr／86Sr的比值远远低于深水区的值。从整体上看,鄱阳湖五大流域的18O主要集中在-6.5%0—4.0‰之间,且年平均变化不大,三个时期的同位素构成亦相差不大。相较其余四大流域,赣江的趋近大气降雨线,这与赣江流域的广阔、流量大以及相对较高的年平均气温有关。鄱阳湖的丰、枯、平水期的稳定同位素的组成差异较大,有明显的季节性变化。鄱阳湖的中心区域(航道)的同位素的含量偏低,越往湖泊外围延伸浓度越来越高,入湖口处水域有明显的稀释效应,最高值主要出现在鄱阳湖边缘的湖汊形成的小湖泊。鄱阳湖己局部具备了发生富营养化的氮磷条件,有逐步向富营养化的趋势发展。鄱阳湖流域富营养化程度在时间和空间上差异较大,枯水期一般大于丰水期污染物的浓度,其富营养物质的输入主要来自五大河流。鄱阳湖流域水环境中重金属污染较轻,存在水相与固相之间的迁移转化,湖区的水生植物及水生生物都处在不同程度的富集现象。鄱阳湖流域有机氯农药污染也较轻,其水体及沉积物中DDT除了来自历史的残留,还有新的污染源输入；不同种有机氯农药的降解程度及方式都不相同,有机氯农药污染存在一定的生态风险。从水环境功能区分析看,自然保护区和景观用水区污染较重,渔业用水次之,而其余水域污染较轻或不受污染。边缘型水体中主要离子来自碳酸盐岩的化学风化过程,该水体在水循环方面与过渡型水体和河道型水体有较大差异,其水的来源主要为周边的径流与降水,且在大部分时间内边缘型水体没有新鲜水来源,‘无法进行外部交换。边缘型水体营养盐浓度在逐年增加,且已经达到富营养的指标；同位素研究表明,边缘型水体的污染主要来源于：工业废水、生活污水、农田污水和水土流失。鄱阳湖流域温度增长趋势将愈加明显,而流域内水量将趋于减少。预计鄱阳湖水位将持续走低,水环境将逐步恶化；鄱阳湖区生活污水和工业废水排放量将面临快速增加的压力,且农业面源污染逐步加重,将造成湖泊水质恶化,水生生态系统结构遭到破坏,湖泊的净化和综合功能减退,进而导致一系列环境问题。结合鄱阳湖及其流域的实际情况和上述关于鄱阳湖水环境的结论,对实际结论进行深一层次的分析研究,得出以下理论层面的结论：处在降雨充沛、工业落后、农业发达地区的季节过水性湖泊,其水环境中富营养化问题最为突出,其所引起的生态风险较高；人文驱动因素中水利设施建设、城市发展和经济发展对其水环境的影响最为突出,且应控制好农业非点源污染。边缘型水体的水质、水文特性与河道型和过渡型水体存在较大的差异,边缘型水体、河道型水体和过渡型水体的水化学类型相似,而在水循环方面存在较大差异；边缘型水体营养盐浓度会逐年增加,发生富营养化等生态风险的概率较河道型水体和过渡型水体高出许多,其污染主要来源于工业废水、生活污水、农田污水和水土流失。更多还原

【Abstract】 With the rapid development of economy and society, the water demand and deterioration of water environment has become more and more serious, which severely restricted the development of world economy. Currently, the problems of water resources missing and water environment depravation were increasingly outstanding, and human activities were one of the main driving factors. Reflects this, comprehensively systematically studied the water environmental characteristic and its evolutionary trends of Lake, appears extremely essential, and the conclusions would provide a scientific basis for water resources protection and management.In recent years, the Poyang Lake water area shrinking, causing serious soil erosion, siltation of rivers and lake, river and lake bed elevation, resulting in Poyang Lake flood storage capacity greatly reduced, more and more Lakes region frequently flooded, and it showed a trend of gradually increasing. Poor agricultural production and land use patterns, the increasingly serious air pollution and the large number of pesticide and fertilizer application, cause the increased input of the nutrients into the lake (such as nitrogen, phosphorus, etc.) and POPs, the deterioration of water environment.Base on the international cooperation projects of water environmental and biodiversity study in Poyang Lake area, the national natural science funds of researching isotopes hydrology in edge deep-water zone of Poyang Lake as well as environment protection and the comprehensive exploitation and utilization of resources in Poyang Lake which has become a central topic for social and economic development in Jiangxi Province, this paper taken Poyang Lake Basin as an example. This dissertation had systematically researched the water chemical characteristics, geochemical characteristics, water quality, hydrologic characteristic, and the evolutionary trends of water environmental. The result revealed the spatial-temporal distribution characteristics of water chemical, the characteristics of water circulation, the characteristics of geochemical.Based on analyzed the status of the water environment and water quality, its water environment evaluation function of Poyang Lake Basin; the characteristics of nutrient salt, its seasonal variation, and the main sources and transport mechanism of water pollution of edge water; the factor of evolutionary trends of water environmental, this dissertation provided a better insight into contributing issues as well as suggestions for future exploitation in the area.The main conclusions have been summarized as follows:The pH of Water in Poyang Lake Basin was slightly acidic to alkaline and the buffer action of acid and alkali were strong; the electrical conductivity of water was below average of the world river. The average salinity in water of Poyang Lake district was 75.5mg/L. According to the distribution of water hardness, hardness in the lake of central was higher than stream outlet. The main hydrochemical type of Poyang Lake was type of, followed by, and then. Ca2+ was the dominant cation, accounted for more than55% of total cations respectively and HCO3-、SO42- was the principal anions. Minerals weathering play a controlling role in chemical composition of Poyang Lake Basin. The concentration of 87Sr/86Sr of lake outlet was higher than lake region and the marginal zone was much less than the deepwater area, while the center of deepwater area was on the high side.From an overall perspective, the isotopic composition of the Poyang Lake was in the range -6.5‰—4‰, and it has no obviously annual change. The isotopic composition of Ganjiang River approached snowprecipitationline, which relevant to year-round high temperatures, plenty of water and Broad valley. The stable isotopes were significantly different between the high water period, low water period and average flow period. The concentration of the isotopes in marginal zone was higher than the central region and the concentration of isotopes was the highest in the small lakes of the margin of Poyang Lake.Poyang Lake was polluted by N and P, which had subjected to eutrophication status at some extent. The eutrophication in Poyang Lake Basin will be heavier and the low water Period was more serious than the high water period. The Poyang Lake nutrients came mainly from five branches. The heavy metal pollution of water environment was light, however, heavy metal can transform in the system of water-sediment and enrich in aquatic plants and aquatic organism. Based on analyzed organochlorine pesticides, the results showed that the pollution was not serious, and DDTs in water and sediment may be derived from recent inputs, except having the use of the aged agricultural. Water environmental function and the water environmental quality appraisal showed that the nature reserve of water and landscape water had been seriously polluted, followed by fishery water, and other water was relatively good.The major ions of edge water were mainly derived from the weathering of carbonate rock. The water circle of edge water was obviously different from river water and lake water, as the main source of water was the surface runoff and rainfall, which results in water, could not be exchanged with outside environment. The concentrations of nutrients were increased year by year, at which had subjected to eutrophication. Isotopic studies suggested that the industrial sewage, life sewage, agricultural wastewater, and soil erosion were the main sources of water pollution.Temperature in Poyang Lake Basin tended to raise, in addition, the amount of water tended to decrease. Poyang Lake water level was expected to continual dropping, and water environmental gradually deteriorates. For the letting out of a large volume of industrial sewage, life sewage, and agricultural nonpoint source pollution had increased gradually, it will cause water quality malignization, make aquatic ecosystem structure destroy, weaken purification functional function of lake, and then lead to a series of environmental problems.Combined with the actual situation and the conclusions of Poyang Lake Basin, the theoretical conclusions have been summarized as follows:Eutrophication was the most serious problem in the seasonal lake with abundant rainfall, agricultural development, and industrial backwardness. The construction of water conservancy facilities, city development and economy development had a prominent impact on water environment. The water quality, hydrologic characteristic, and water circulation of edge water was obviously different from river water and lake water, while they had the similar hydrochemical type. The concentrations of nutrients were increased year by year, and studies suggested that the industrial sewage, life sewage, agricultural wastewater, and soil erosion were the main sources of water pollution. The odds were higher that eutrophication and the dispersion of schistosomiasis of edge water than river water and lake water.更多还原