【作者】 安文超；

【导师】 李小明；

【作者基本信息】 山东大学 ， 环境工程， 2008， 博士

【摘要】 南四湖是山东省最大的淡水湖泊,同时也是我国北方最大的淡水湖泊,作为南水北调东线工程的重要输水通道和调蓄湖泊,近年来南四湖整个湖区水质已基本属于中度富营养化和富营养化水平,富营养化已成为南四湖不容回避的一个最重要的水环境问题。在南水北调工程运行后,南四湖的水流方向将发生改变,即调水将由下级湖流入上级湖,南四湖主要入湖河流绝大部分分布于上级湖,近30年来,这些河流水质长期处于严重污染状态。调水后,这些河流将严重影响调水水质。由于国家对南水北调沿线采用了严格的污水排放标准,对于各入湖河流的达标排放将按时实现。但是长期受严重污染的河流底质对入湖河流水质的影响难以预测。对这些河流河口区的表层沉积物的重金属和营养盐进行相关研究,可为调水前沉积物研究积累数据资料,为湖区开展流域污染综合治理提供科学依据。在外源磷负荷得到削减和控制的条件下,底泥污染物势必会对调水形成二次污染,内源磷负荷成为决定调水水质的关键所在。因此,研究沉积物中内源磷负荷及其释放,以及沉积物对磷的吸附作用就显得尤为重要。对沉积物中磷的赋存形态、含量变化以及其中的生物有效部分进行分析研究,有助于了解沉积物磷的迁移转化过程以及各形态磷在浅水湖泊富营养化过程中起的作用,对生物有效磷的控制和削减可能是解决南四湖富营养问题的一条重要途径。基于以上,对南四湖表层沉积物进行了相关研究,主要研究结论如下:应用spot-5多光谱彩色遥感影像数据（2006.6月数据）,对南四湖湖区地表覆盖现状进行了分析,分析结果显示南四湖湖区地表覆盖情况复杂,明显区别于我国其它的大型浅水性湖泊,湖区可基本分为5种代表性地表景观,分别是开阔水域、鱼塘、水生植被、农田和陆地植被,其中开阔水域的面积仅占湖区总面积的41.71%。水质监测结果表明,南四湖重点污染区域水质不能满足GB3838-88中Ⅴ类水的要求,大部分区域水质距Ⅲ类水的要求相距甚远,TP超标严重,并且在湖区由北向南呈明显的递减趋势.水中Cr、Cu、Mn、Pb、Zn含量较低,均能达到GB3838-88中Ⅰ类水标准,无超标现象。通过对南四湖主要入湖河流表层沉积物中重金属（Al、Ca、Fe、Mn、Zn、Cr、Cu、As、Pb、Ni和Cd）分布状况的研究发现,西支河、泗河、万福河和梁济运河是南四湖上级湖重金属污染的主要河流,而一直被视为污染严重的洸府河对南四湖的重金属污染的贡献并不大,重金属污染不是洸府河治理的首要目标。泗河沉积物中各重金属元素浓度均较小,但是结合现场调查以及对上覆水中重金属浓度的同步监测可知,泗河受重金属污染较严重。因此将沉积物中重金属污染评价结论作为治理依据时,还应结合沉积物的化学组成、上覆水和间隙水中重金属浓度、水利条件等因素进行综合考量。河流沉积物中Cu、Pb和Zn之间存在明显的相关性,特别是Cu和Zn之间呈显著正相关;Mn与Al、As、Cd、Cr和Ca表现出明显的相关性,Mn是这几种重金属元素的主要赋存相;Fe仅与Pb之间具有相关性;Ca与Al、As、Cd和Mn之间具有显著的相关性,土壤侵蚀和岩石风化作用对这几种金属元素组成具有影响。地积累指数法与潜在生态危害指数法的评价结果均显示南四湖地区受Cd污染严重,受As污染次之,其它金属元素属于较轻的污染程度。南四湖河流沉积物中Cd的质量浓度高达2.65～5.04 mg·kg^-1,作为一种危险的环境污染物,沉积物中的含量远远高于我国环境监测总站公布的湖相沉积物母质Cd的背景值0.098mg·kg^-1,较高浓度的Cd应引起有关部门的高度重视,以保障南四湖地区人民的身体健康。南四湖沉积物中总磷与磷形态的相关研究结果显示,沉积物中TP平均含量占沉积物总质量的0.08%。不同形态磷的质量浓度存在很大差异,将各个形态的磷质量浓度进行排列可知IP＞Ca-P＞OP＞Ads-P＞Fe-P＞Al-P。沉积物中无机磷含量要远远大于有机磷含量,无机磷当中Ca-P是最主要的组成部分,IP和Ca-P的最大值都出现在航道,Ads-P的最大值出现在受人为影响严重的航道和梁济运河,Al-P在南四湖中的分布具有一致的规律,都处于近于不可检出的范围内,除了洸府河之外,Fe-P的质量浓度都在17.72 mg·kg^-1以下,有机磷最大质量浓度出现在梁济运河,该地区人类活动频繁,不仅是京杭运河的重要组成部分,也是济宁市污水排放的主通道。通常情况下流域河道沉积物中的有机磷含量应比湖区沉积物高,本研究中南四湖湖区较高浓度的有机磷可能是由于大量水生植物残骸长期遗留在湖底,发生降解,导致沉积物有机质含量较高引起的。沉积物磷的主要组成部分Ca-P、Ads-P、OP和TP之间都存在着正相关性,其中TP与Ca-P、Ads-P两种无机磷之间的相关性最显著;Ads-P与Ca-P之间存在着正相关性;IP之中只有Ads-P与OP之间存在相关性,磷的释放过程中,酸可提取有机磷在微生物的作用下转换为易于被生物所利用的无机磷,这很可能是导致湖泊富营养的重要过程之一;Fe-P和Ca-P之间存在明显负相关性,沉积物中确实存在着Fe-P和Ca-p之间的相互转化。生物有效磷的最大值出现在洸府河,惠河、万福河、航道和梁济运河的生物有效磷含量也相对较高。BAP含量在四个湖区的排序为:独山湖＞昭阳湖＞微山湖＞南阳湖,独山湖、昭阳湖和微山湖高浓度的BAP值应引起我们更多的关注。BAP可以比较客观的反映南四湖沉积物受人类活动影响的大小,以及对河口生态环境的危害程度,并且可以作为一个反映南四湖污染程度评价的主要指标。BAP与磷形态的相关性分析显示,BAP只与OP之间存在显著正相关,由OP可以粗略的估算出沉积物中潜在的可释放磷,即有效的内源磷负荷。与主要理化性质之间的相关性方面,TP仅与Al、Mn之间存在正相关性,与其它沉积物理化性质参数之间相关性均不明显;有机磷仅与有机质、Ca含量之间存在着正相关关系,南四湖沉积物中有机磷的含量很大程度上取决于有机质含量的多少;Fe-P含量与水体PO₄^3-浓度关系密切,Fe-P对湖泊水体富营养状况存在着重要的影响,可以作为指示湖泊水体富营养化程度的一项指标,沉积物中大多数的铁因与硅结合而不具反应活性,即沉积物中的活性铁极少,仅有很少部分具有反应活性的铁参与了磷的吸附是导致南四湖沉积物中Fe-P含量较少的一个主要原因。沉积物对磷的吸附特性的相关研究表明,南四湖表层沉积物对磷的吸附在48h时基本都达到平衡状态,主要的吸附发生在1 h内。最大吸附量的分布呈现较明显的趋势,即由南阳湖向微山湖逐级递减.在本研究试验条件下,沉积物吸附·解吸浓度的变化范围为0.010～0.157 mg·L^-1,惠河、复新河、洸府河、大沙河以及4个湖区的沉积物样品目前不具有向上覆水释放磷的趋势。沉积物磷吸附特征参数与Ads-P都具有显著的正相关关系,Ads-P可以作为评价南四湖污染状况的一项重要指标,磷吸附特征参数与沉积物的污染程度紧密相关。c_EPC与Ads-P、TP、IP和Ca-P之间都具有较显著的正相关性,在相同的上覆水浓度下,营养水平高的沉积物易于发生解吸,从而使湖泊富营养化加剧。磷吸附的特征参数之间,m与TQ_max之间有显著的正相关性,m不仅体现的是对外来磷的吸附效率,还应当包含对本身释放磷的再吸附的效率;沉积物的NAP与Q_max和TQ_max之间都具有较好的正相关性,同时Q_max与TQ_max之间也有显著的正相关关系;NAP与其c_EPC之间有明显的正相关性,总的趋势为当上覆水中磷含量相等时,具有高的NAP的沉积物易向上覆水体释磷,反之具有较低NAP的沉积物易于从水中吸附磷。在释放方面,对于不同富营养化程度的沉积物而言,在强酸和强碱条件下的磷释放量都要远远大于中性条件下。沉积物中Fe-P/Ca-P比值可作为鉴别酸化或碱化引起的磷释放的简单指数,南阳湖、微山湖的沉积物Fe-P/Ca-P比分别为1.05、0.24.环境的碱化更易于引起南阳湖沉积物的磷的释放,而微山湖沉积物在酸性条件下释放量随着pH值改变的幅度要大于碱性条件下的,此沉积物磷释放趋势对于环境的酸化更为敏感。pH值影响磷释放的根本原因是由于在不同pH值条件下Fe、Al、Ca等元素与磷的不同结合状态发生了改变,促进了不同形态磷之间的相互转化。更多还原

【Abstract】 Nansi Lake is the largest lake in Shandong province and the northern area of China,which is an important buffer lake of the South-to-North Water Diversion Project （east route）.Eutrophication has become the central problem of water environment in Nansi Lake where the eutrophic state is from mesotrophic state to hypereutrophic state. Afer the water diversion project,the route of the water will be changed that is from the lower lake to the upper lake.The main inflow rivers that are heavily polluted all locate in the upper lake and the water of the inflow rivers will be a tremendous hidden trouble to the water coming from Jiangsu province.It is important to carry through the relative investigations on the heavy metals and organic compounds contained in the surface sediments of the inflow rivers’ estuaries for making managements of Nansi Lake. Under the control of external load,some sedimentary phosphorus can be released at certain periods of the year and sedimentary phosphorus will determine the quality of water.So it is crucial to investigate the phosphate adsorption and release characteristics of lake sediments.To investigate various P-binding forms and biologically available phosphorus（BAP）will do good to find out the rule of phosphorus’ transference and transformation at the sediment-water interface.It is a potential method to alleviate the degree of eutrophication by controlling and cutting BAP.Relative researches of the surface sediments that were sampled from the lake and inflow rivers were carried on and the main results are as follow.The overlay of earth’s surface is analyzed according to the spectral data of spot-5. The analytical results show that the overlay of earth’s surface is complicated which is obviously different from the other shallow lakes in China.There are five leading types of earth’s surface in Nansi Lake,including open water area,pound,hydrophytic vegetation,farmland and terraneous vegetation.The proportion of open water area to whole lake area is only 41.71%。The quality of water which is heavily polluted could not meet the Grade V of the ’China surface water quality standard（GB3838-2002）’.The water quality of mostly water area exceed the GradeⅢof GB3838-2002 and the concentrations of total phosphorus are degressive from the north to the south.The concentrations of Cr、Cu、Mn、Pb、Zn could meet the GradeⅠof GB3838-2002.The concentrations of heavy metals（Al,Ca,Fe,Mn,Zn,Cr,Cu,As,Pb,Ni and Cd）in the sediments of Nansi Lake and its inflow rivers show that Xizhi River,Si River, Wanfu River and Liangji Canal are heavily contaminated by heavy metals.The concentration of heavy metals in the surface sediment is relatively low and contamination of heavy metal is not the chief problem of Guangfu River.The concentrations of every kind of heavy metals are litter in the sediment of Si River. Combined with spot investigation and analysis of concentrations of heavy metals in the surface water,Si River is badly contaminated.It is necessary to combine chemical components,concentrations of heavy metals in the surface water,hydrological condition with the concentrations of heavy metals in the sediments to evaluate the degree of contamination.The intercorrelations between Cu,Pb,and Zn contents in the sediments are significant,especially Cu and Zn.Mn and Al,As,Cd,Cr,Ca have significant relationships,and Al,As,Cd,Cr,Ca always compound with Mn in the sediments.Fe only has correlation with Pb.Corrasion and efflorescence of sediment and soil affect the concentrations of Ca and Al,As,Cd,Mn in the sediments together,and Ca has prominent relativity with Al,As,Cd and Mn.The evaluative results of I_geoand RI both shows that the sediments of Nansi Lake are badly contaminated by Cd,and contamination caused by As takes second place. Other heavy metals just contaminate the sediments lightly.As an extremely dangerous element,Cd ranges from 2.65 to 5.04 mg·kg^-1in the Nansi Lake sediments.The concentrations of Cd are all higher than the lakes’ background concentration cognizanced by Environment Monitoring Station in China,so governmental department should pay more attention to Cd in the Nansi Lake sediments to ensure the water quality.The investigative results of total phosphorus and phosphorus fractions in the sediments show that the average content of total phosphorus（TP）is 0.08%,and the sediments of Nanyang Lake,Dushan Lake,and the rivers in the west of Nanyang Lake have higher TP contents compared with Zhaoyang Lake,Weishan Lake and the rivers in the east of Nanyang Lake.Different phosphorus fractions contents varies greatly,and the phosphorus fractions of the sediments are IP＞Ca-P＞OP＞Ads-P＞Fe-P＞Al-P. Inorganic phosphorus（IP）contents are higher than organic phosphorus（OP）,and calcium bound phosphorus（Ca-P）is the major phosphorus fraction.The concentrations of IP and Ca-P in the sediment of Sea-route are the largest,and Ads-P contents of Sea-route and Liangji Canal where are heavily affected by human activities are higher than other sampling sites.Iron bound phosphorus（Fe-P）contents are less than 17.72 mg·kg^-1except for Guangfu River.OP content of Liangji Canal that is an important part of Jinghang Canal is the highest of all sediments because Liangji Canal is a main channel of wastewater coming from Jining City and polluted badly.As a rule,OP content of river sediment is higher than it of lake sediment,but in the research OP contents of lake sediments are relative high.It is the main reason causing high concentrations of OP that a great deal of hydrophytes’ debris enriched in the sediment of lake,after decomposition,leads to high content of organic matter.The relationships between TP content and Ca-P,Ads-P and OP contents are significant,and Ca-P and Ads-P have the most significant relationship.Among all inorganic phosphorus only Ads-P has a correlation with OP.In the course of phosphorus release,acid extractable phosphorus could be converted to inorganic phosphorus by microbe that is prone to be used by aquatic organism,and the conversion probably is a crucial part of eutrophication course.Besides the positive correlationships,Fe-P has negative correlationship with Ca-P,so there is mutual transformation between Fe-P and Ca-p in the sediment.The sediment of Guangfu River has the highest content of BAP,and the other sediments with high concentrations of BAP were obtained from the Hui River,Wanfu River,Sea-route,and Liangji Canal that were polluted heavily by municipal sewage, chemical fertilizer overusage,and wastewater of ships.The BAP of the sediments in the four lakes are Dushan Lake＞Weishan Lake＞Zhaoyang Lake＞Nanyang Lake.The high ratio of BAP to TP could bring more concerns with the sediments of Dushan Lake, Zhaoyang Lake and Weishan Lake.BAP could be considered as an important index to indicate contaminated degree of Nansi Lake sediment and to reflect the human influences on the lake.BAP and OP have significant relationship merely,so OP content could be cursorily considered as potential phosphorus that could be used by aquatic organism in the sediment.TP has an obvious relationship with Alox,MnO and has no evident relationship with the other physical chemistry parameters.The positive relationships between OP content and organic matter,CaO contents are found and OP content to a great extent lies on organic matter content.Fe-P greatly influences eutrophication degree of Nansi Lake and Fe-P has close relationship with PO₄^3-content in water.The low Fe-P content partly due to few amount of active iron in Nansi Lake sediment and most of iron are integrated with silicon.The majority of phosphate adsorptions on the samples have similar trends that are almost completed in 10 h and the sorption process reaches equilibrium after 48 h. Distribution of maximal amount of phosphorus adsorbed(Q_max)has a visible trend,that is to say Q_maxgradually decreases from Nanyang Lake to Weishan Lake.In a condition of the experiment,zero equilibrium phosphorus concentration(c_EPC)ranges from 0.010 to 0.157 mg·L^-1,and the sediments of Hui River,Fuxin River,Guangfu River,Dasha River,the four lakes will not desorb phosphorus and will not threaten the water at present.Ads-P has positive relationships with all characteristic parameters of phosphorus adsorption.Ads-P could be considered as an important index to indicate contaminated degree of Nansi Lake sediment and water,and characteristic parameters of phosphorus adsorption close associate with contaminated conditions,c_EPChas positive correlation with Ads-P,TP,IP and Ca-P.In the same condition,the sediment with higher trophic level desorbs phosphorus easily leading to aggravate trophic degree.Adsorption efficiency（m）has remarkable positive relationship with total maximal amount of phosphorus adsorbed(TQ_max).The m is the sum of adsorption efficiency of the sediments adsorbing the phosphorus coming from external and the phosphorus desorbed from the sediments.Native adsorbed phosphorus（NAP）has positive correlation with c_EPCand the trend is that the sediment with higher NAP easily desorbs phosphorus to the water,contrarily the sediment with lower NAP easily adsorbs phosphorus.Phosphorus release quantity of sediment at different trophic level in a acid condition or a alkali condition is larger than in a neutral condition.Fe-P/Ca-P could be considered as a index to indicate phosphorus release arousing by acidification or basification.The index of Nanyang Lake and Weishan Lake is 1.05 and 0.24.Therefore basification is prone to accelerate phosphorus release of Nanyang Lake sediment and Weishan Lake sediment is sensitive to acidification to release more phosphorus. Transformations of Fe-P,Al-P and Ca-P are different in dissimilar pH,as a result the effect of pH on phosphorus release is discrepant.更多还原