【作者】 陈航；

【导师】 王宁；

【作者基本信息】 安徽大学 ， 环境科学， 2012， 硕士

【摘要】 巢湖富营养化问题已影响到沿岸居民的生产和生活,而磷是导致巢湖水体富营养化的关键性因子。经过多年的控制和治理,点源污染已逐步得到控制,农业非点源污染和内源污染逐渐成为巢湖流域磷主要来源。内源磷在环境条件发生变化时,如温度、溶解氧和扰动等,可以作为“源”向上覆水释放磷,维持水体富营养化状态。本文以巢湖东部水源地及入湖河流的磷为研究对象,分析了磷的形态特征及时空变化规律,初步探讨其可能的主要来源,并进行沉积物生物可利用磷释放模拟实验,讨论微生物对这一迁移转化过程的影响。工作主要集中在以下几个方面：1、巢湖东部水源地及入湖河流磷形态时空变化特征和来源探讨巢湖水体常年呈微碱性,入湖河流磷呈现明显的季节性变化,丰水期高于枯水期；双桥河磷浓度高于柘皋河和小柘皋河；水源区磷浓度受陆源影响呈现相似的季节性变化,湖区磷随时间变化较小,且离主湖区越近磷含量越低。柘皋河和小柘皋河磷主要来源是农业用水和生活污水,双桥河还受工业废水和固体污染物的影响,水质较差。三条入湖河流均以非点源污染为主,因此水体磷浓度受降雨影响较大,丰水期高于平水期和枯水期。湖区与入湖河流磷浓度存在差异,河流相对较高,入湖河流是湖泊磷污染的重要来源。颗粒磷为水体磷主要形态,多源于地表径流和生活污水等非点源污染,对水源区水体磷影响较大。2、生物可利用磷迁移转化的模拟研究在巢湖东部水源地水体磷时空分布和来源探讨的基础上,采集西半湖沉积物,进行室内模拟实验,探索了环境因素(温度、溶解氧、水力扰动及灭菌)对上覆水和沉积物中生物可利用磷形态的影响。巢湖西半湖水体和沉积物样均呈微碱性,水体总磷超过v类水标准,颗粒磷为主要形态。沉积物生物可利用磷基本表现为藻类可利用磷(AAP)>水溶性磷(WSP)>碳酸氢钠提取磷(OLP)>易解析磷(RDP)。动力学实验结果表明：上覆水磷初始浓度为0.05mg/L时,沉积物表现为“源”；上覆水磷初始浓度为0.5mg/L时,沉积物表现为“汇”。在不同的环境条件下,灭菌体系中上覆水磷浓度均明显高于未灭菌体系：灭菌体系上覆水总磷浓度随温度升高而上升,未灭菌体系变化趋势与其相反,减小以正磷酸盐为主。好氧状态下水体总磷浓度高于厌氧状态,溶解性总磷浓度小于厌氧状态。扰动使水体总磷浓度显著升高,且随扰动频率的增加而呈增大的趋势,在扰动后水体颗粒磷升高,溶解性正磷酸盐和溶解性有机磷浓度降低,主要原因是水体中细小悬浮颗粒物的吸附和絮凝作用,所以扰动仅引起总磷的释放,而不一定导致溶解性磷酸盐的释放。不同环境条件下,沉积物中生物可利用磷浓度明显高于灭菌体系,四种生物可利用磷含量大小顺序一致,基本表现为AAP>WSP>OLP>RDP。微生物对沉积物RDP迁移转化影响较小；模拟实验后沉积物WSP均小于原沉积物,呈现一定的释放,温度和微生物作用对WSP影响较小；AAP和OLP变化趋势相似,随温度升高呈波动状态,其原因有待于进一步研究。厌氧状态下生物可利用磷基本高于好氧状态。沉积物扰动导致磷形态分布和生物可利用磷含量发生改变,转速60r/min条件下AAP含量明显低于对照实验,底泥再悬浮减小了铁结合态磷对AAP的贡献,抑制了沉积物AAP的形成,但140r/min扰动下沉积物BAP大幅上升,其原因还有待于进一步研究。3、微生物作用下生物可利用磷转化的模拟研究本文研究了不同温度条件下,腐殖质还原菌对水-沉积物界面生物可利用磷形态转化的影响。腐殖质还原菌促进上覆水生物可利用磷浓度升高,沉积物表现为“源”。当体系中存在自然菌群时,虽然外加腐殖质还原菌能促使上覆水磷浓度升高,但还是低于上覆水初始浓度,沉积物呈现“汇”的特征。在腐殖质还原菌单独作用下,上覆水生物可利用磷含量更高,腐殖质还原菌可能削弱沉积物中原有微生物的聚磷作用。腐殖质还原菌和自然菌群都能促进沉积物生物可利用磷的形成和累积。温度变化下,除了AAP, WSP、 OLP和RDP含量均是在腐殖质还原菌的单独作用下最大。外加腐殖质还原菌对WSP影响较小；在沉积物自然菌群存在时,外加腐殖质还原菌对沉积物OLP含量影响较小；腐殖质还原菌促进RDP形成,在原沉积物自然菌群存在下,削弱了腐殖质还原菌对沉积物RDP形成的促进作用。60r/min状态下沉积物BAP波动较大。AAP含量随转速升高呈先升高后降低的趋势,与上覆水DIP相反。腐殖质还原菌促进沉积物WSP和RDP形成。更多还原

【Abstract】 Lake eutrophication already has affected the production and life of coast residents.Phosphorus is a key factor leading to the eutrophication of Chaohu Lake. After years of control and governance,the point sources are gradually being controlled, and the agricultural non-point source pollution and internal source pollution become the main sources of phosphorus pollution in Chaohu Lake Basin. When various environmental factors influence internal phosphorus,such as temperature, DO and disturbance, phosphorus in the sediments can release and lead eutrophication.The character of phosphorus speciations were investigated,and possible sources were estimated We maked the simulation experiment of sediment bioavailable phosphorus release,and discuss the impact of microorganisms on the transformation process. The main work is in the following aspects:1.Speciations character and sources of phosphorus in the eastern water source areas and inflow rivers of Chaohu LakeThe overlying water is perennial slightly alkaline.The content of phosphorus of inflow rivers display seasonal variations obviously,high-water period higher than low-water period. The concentration of phosphorus of Shuangqiao river are higher than Zhegao River and XiaoZhegao River.Phosphorus concentration of water source areas display a similar seasonal variations influence by land. Concentration of phosphorus in the Lake District have a smaller change over time. The more recent from the lake district, the lower of the phosphorus contentThe main sources of phosphorus pollution of The Zhegao and XiaoZhegao River are agricultural water and domestic sewage. The Shuangqiao river is also affected by industrial waste water and solid waste,so water quality is poor. The three inflow rivers are subject to non-point source pollution. Therefore, rain has a great impact to water phosphorus concentrations. The phosphorus content of the high-water period is higher than the level of nornal-water period and low-water period. Comparing with phosphorus concentration of water in lake,the phosphorus concentration of water in inflow rivers are higher. Inflow rivers are the important sources of the phosphorus pollution in the lake. PP,which is the main form of phosphorus in water,mainly come from the non-point source pollution such as surface runoff and sewage. PP has a great impact on phosphorus of the water in the lake.2.Simulation study of bio-available phosphorus transportation and transformationThe simulation is based on the study of speciations character and sources analysis of phosphorus in the eastern water source areas of Chaohu Lake. Collect the sediments of western lake,and then conduct simulations. Variation of bio-available phosphorus speciations in overlying water and sediments are discussed under different environmental conditions (Temperature, DO,hydraulic disturbance and sterilization).The samples of overlying water and sediment display a slightly alkaline. TP is worse than V class water standard. PP is the main form. BAP of sediments show that AAP>WSP>OLP>RDP. Kinetic experiment shows:when the initial phosphorus concentration of the overlying water is0.05mg/L, sediment shows " source " features; when the initial phosphorus concentration is0.5mg/L, sediment shows " sinks " features.Under different environmental conditions, phosphorus concentrations in the overlying water of sterile system is significantly higher than bacteria system.TP concentration of the overlying water in the sterile system increases with increasing temperature.Bacteria system changes in the the opposite with sterile system,mainly to reduce the DIP.TP concentration of the overlying water in aerobic condition is higher than anaerobic condition.On the contrary,TDP concentration in anaerobic condition is higher. Disturbance makes TP significantly increase.there is a tendency that TP concentration increase with the increase of the frequency of disturbance.After the disturbance, PP increases, DIP and DOP reduce.The main reason is that the adsorption and flocculation of small suspended particles in water. Therefore, disturbance cause the release of the TP only, but not necessarily lead to the release of dissolved phosphate.Under different environmental conditions, phosphorus concentrations in the sediment of sterile system is significantly higher than bacteria system. BAP of sediments show that AAP>WSP>OLP>RDP.The influence of microbial effects on RDP and WSP is slight.And Temperature has a little influence on the WSP. AAP and OLP have the same change trend, presented a fluctuant condition. BAP of sediment in anaerobic condition is higher than aerobic condition. Sediment resuspension lead to Distribution and content change of BAP. Sediment resuspension can inhibit the AAP formation.When60r/min, the content of AAP is lower than control experiment obviously.But, BAP of sediment increase,when140r/min. The reason needs further study.3. Simulation experiment on bioavailable phosphorus conversion with microorganismsUnder different temperature conditions, humus-reducing bacteria’s role of bioavailable phosphorus conversion on the water-sediment interface was discussed.BAP concentrations of the overlying water are promoted by humus-reducing bacteria. Sediment shows " source " features.When exist natural microflora in the system, phosphorus concentration of the overlying water is lower than initial concentration,even though humus-reducing bacteria promote phosphorus concentration rise. Sediment shows " sinks " features.By the action of humus-reducing bacteria alone, BAP concentrations of the overlying water are higher. Humus-reducing bacteria may decrease the phosphorus accumulating of the original microbial.Humus-reducing bacteria and natural microflora can promote the formation and accumulation of BAP. The contents of WSP,OLP and RDP are the maximum in the action of humus-reducing bacteria alone,except AAP. Humus-reducing bacteria has a little influence on WSP.When exist natural microflora in the system, Humus-reducing bacteria has a little influence on OLP. Humus-reducing bacteria can promote the formation of RDP,however, natural microflora decrease effect.BAP of sediment fluctuate quite a bit under60r/min. The contents of AAP increase and then decrease with the increase of the frequency of disturbance, as opposed to DIP.Humus-reducing bacteria can promote the formation of RDP and WSP.更多还原