2,4,6—三氯酚在模型水生生态系统中的归宿

测定了模型水生生态系统水、底泥中２，４，６－三氯酚（ＴＣＰ）浓度随时间的变化值，以及ＴＣＰ从水中挥发、光解、底泥吸附、解吸、微生物降解的速率常数。假设水中ＴＣＰ的迁移和转化遵循一级速率过程，水中物质平衡能通过数学等式来描述，显示出室系统数学模型能粗略预测模型水生生态系统中ＴＣＰ浓度随时间的变化。最后，应用该模型预测了排放到天津室外兼性塘中ＴＣＰ的迁移、归宿，发现１５ｄ后出口水中ＴＣＰ浓度已降低到入     

同位素示踪法研究有机污染物在模拟水生生态系统中的行为

应用同位素示踪技术，研究了模拟水生生态系统中三氯苯、邻苯二甲酸正丁酯，２，４，６－三氯酚－＾１４Ｃ的分布、迁移、转化行为。实验周期后，水中污染物浓度分别降低了８９％，８０％，９５％以上，三氯苯在底泥和浮游生物中有积累。测定了标记物在水、悬浮物、＾１４ＣＯ２吸收溶液，ＸＡＤ－２树脂上的放射性强度。假设水中标记物的降解遵循一级速率过程，２４ｄ后，水中２，４，６－三氯酚－＾１４Ｃ浓度已降为原来浓度的５％     

土霉素残留在模型池塘生态系统中的消除与迁移规律

按生态学方法建立和培育模型池塘生态系统,选择符合要求的生态池分别添加0.8 mg L-1、4.0 mg L-1、20.0mg L-1和100 mg L-1盐酸土霉素,定期采集水样和底泥样品,用高效液相色谱方法进行药物浓度测定.结果表明,水中药物在用药后消除迅速,其消除半衰期分别为27.32 h、34.10 h、45.25 h、56.07 h.底泥中土霉素消除较缓慢,底泥0～2 cm表层中的土霉素消除半衰期分别为38.18 d、36.75 d、46.75 d、33.38 d.底泥2～4 cm中的土霉素消除半衰期分别为53.45 d、59.58 d、47.17 d、50.83 d.结果提示,底泥中的土霉素大部分以原形药物形式存在,并有明显的从表层向下层迁移的过程;土霉素的浓度对底泥中土霉素的半衰期和平均滞留时间无明显影响.表8参15     

水体氮浓度、形态对黑藻和狐尾藻光合特征的影响

利用黑藻和狐尾藻研究了水体氮浓度和形态对沉水植物光合特征的影响.结果表明,狐尾藻在TN≤3mg/L、黑藻在TN≤4mg/L范围内其净光合速率、最大净光合速率和暗呼吸速率均随水体总氮浓度的增加而增大,对光合作用有利,超过这个范围时,这两种供试植物的光合作用受到抑制,净光合速率和最大净光合速率降低,暗呼吸速率急剧上升;在本实验条件下,这两种供试植物的光合补偿点和光合饱和点随氮浓度的变化没有表现出规律性.在总氮一定的条件下黑藻和狐尾藻的净光合速率和最大净光合速率均随水中铵氮的增加而降低,暗呼吸速率和光合补偿点随铵氮增加而升高,说明水体铵氮的增加对黑藻和狐尾藻具有一定的毒害作用,抑制了光合作用;在本研究条件下光合饱和点对氮形态比例的变化没有明显的响应.结合我国湖泊N营养现状,可初步推断我国大部分湖泊氮浓度不会对黑藻和狐尾藻的光合作用产生直接的危害,但在水生生态系统的恢复过程中,要根据水生植物对不同氮形态的喜好特性和水质情况选择先锋物种.图2表3参27     

底泥中重金属毒性的室内孔隙水分析技术

根据孔隙水中重金属的浓度可以判定底泥中重金属的毒性但获得真正的底泥孔隙水十分困难。本文提供了一套简便易行的室内原状孔隙水取样技术,将碳化硅砂芯埋入底泥,添加表层水并静置９０ｄ,通过渗滤获得孔隙水,测定孔隙水中重的浓度,所得结果与微生态系统暴露试验中生物指示的重金属的毒性大小相吻合,与生物积累重金属的浓度显著正相关。     

城市河流中铬污染的迁移

本文着重探讨城市河流中铬(Ⅲ)的迁移、沉积和溶出规律,以野外实测及模拟试验数据论证了水中悬浮物的吸附是铬沉降到底泥中的主要途径。发现铬污染物沉积至底泥的量是呈等比级数规律增加的,但底泥中的铬一般不易被水解吸,不会造成对水质的影响。     

不同生活型植物腐解过程对人工湿地水质的影响研究

为探讨不同生活型水生植物腐解对石佛寺人工湿地水体水质的持续影响,在室内模拟3种生活型(浮叶型、挺水型和沉水型)6种水生植物(槐叶苹Salvinia natans和丘角菱Trapa japonica;蒲草Typha angustifolia和荷花Nelumbo nucifera;穗状狐尾藻Myriophyllum spicatum和金鱼藻Ceratophyllum demersum)的腐解过程,研究植物类型、生物量以及底泥对营养盐释放过程的影响程度。结果表明:(1)浮叶植物和沉水植物最易腐解,而挺水植物腐解最慢,沉水植物腐解最彻底,且生物量越大释放的营养物质越多;(2)同生活型植物之间p H值的变化具有很强的相关性(r0.826,P0.05),且底泥不影响p H的变化趋势,DO变化趋势因生活型不同存在明显差异;(3)挺水植物有机物释放过程较浮叶植物和沉水植物漫长,氮和碳的变化有一定相关性,底泥不影响水中氮的变化趋势,但对水中氮的浓度高低有影响;(4)浮叶植物组和挺水植物组磷的释放速率高于沉水植物,水体中磷浓度的高低与底泥和植物生物量有关,磷在水体和底泥存在明显吸附沉淀和迁移现象。     

运河(杭州段)沉积物中Cu和Zn的释放特征

采用模拟试验研究了运河（杭州段）沉积物中Cu和Zn的释放规律，以及投加石灰、曝气等地表水治理手段对其释放规律的影响，结果表明，沉积物中Cu的释放速率很快，在1-2d内沉积物-上覆水间Cu的分配即达到平衡，而Zn的释放速率较慢，在21d的模拟试验中上覆水Zn的浓度仍在增加，运河沉积物的释放尽管不会导致上覆水中Cu和Zn浓度超过地表水的二类标准，但显著超过了渔业水质标准，对运河的水生生态系统构成威胁，采用投加石灰和水体曝气可以有效降低上覆水中Cu和Zn的平衡浓度。     

大宝山矿区氟污染特征及土壤溶出状态

对广东大宝山矿区周围尾矿水、河水等水体系统中的氟质量浓度进行了分析,利用水质分类的方法研究氟的来源及分布规律,并在实验室内进行土壤溶出实验,进一步证明氟的来源.研究结果表明:大宝山矿区水质类型主要有以下4种:Ca-SO4,Mg-SO4,Ca-HCO3,Ca-Mg-SO4.其中Mg-SO4型水质中氟含量比较高,最高达到16.68 mg·L-1;从时空分布来看,水中F质量浓度存在着明显的季节与地域特征,雨季氟含量要比旱季低,在研究流域内水中氟质量浓度的分布规律是从尾矿库到滃江呈降低趋势,这说明氟来源于矿山.溶出实验结果表明:尾矿类土样酸化严重,硫化物氧化促进了氟化物的溶出,溶出液pH变化与SO42-浓度变化都证明了这一点;表层土样溶出F质量浓度由大到小的排列顺序为:槽对坑尾砂库表土,铁龙尾砂库外排河流底泥,上坝村水稻田土.槽对坑尾砂库分层土样溶出F.质量浓度和易溶氟化物浓度由大到小的排列顺序为:表土,0.5m,1 m.溶出实验进一步证明了氟来源于矿山.     

浮叶植物重建对富营养化湖泊氮磷营养水平的影响

利用太湖五里湖污染底泥，在不破坏表层沉积物形态和结构的情况下，利用大口径的采样器采集沉积物柱状样，研究浮叶植物荇菜（Limnanthemun nymphoides）在此底泥上适应性生长情况及其对水体以及沉积物中氮磷的影响。结果表明，在培养实验过程中，荇菜生长使上覆水体中的氮、磷营养水平逐渐降低，藻类的生长明显受到克制，水体透明度增加，水质逐渐改善。通过植物根系对沉积物和问隙水中营养盐的直接吸收，使表层（0～5cm）沉积物与问隙水中氮磷营养盐的水平在实验结束后有明皿下降，对于控制沉积物内源营养盐释放有重要的作用。因此，恢复以水生植物为丰的水生生态系统足重建富营养湖泊生态系统和控制湖泊内源负荷的重要措施。     

A mathematical model to estimate nitrate release from ocher pellets applied to anaerobic benthic sediment

A mathematical model was developed to estimate nitrate release from ocher pellets in benthic sediment. Ocher pellets, called “limnomedicine,” consisting of ocher and calcium nitrate were used to suppress phosphorus release from contaminated sediment under anaerobic conditions. The proposed model represents the fate and transport of nitrate released from the pellets, in both the water column and the sediment. Most of the nitrate (83.6%) released from the pellets was consumed in the degradation of organic matter and FeS in the sediment over a period of 12 days. While an increase in pellet dosage helps to accelerate the sediment treatment rate, it also has the effect of increasing the mass of nitrate that diffuses into the water column. Quantitative analysis of these effects using the proposed mathematical model makes it possible to determine the proper pellet dosage based on sediment conditions such as organic matter content.     

Relating effect and response traits in submersed aquatic macrophytes.

Reliably predicting the consequences of short- or long-term changes in the environment is important as anthropogenic pressures are increasingly stressing the world's ecosystems. One approach is to examine the manner in which biota respond to changes in the environment ("response traits") and how biota, in turn, affect ecosystem processes ("effect traits"). I compared the response and effect traits of four submersed aquatic macrophytes to understand how water level management may affect wetland plant populations and ecosystem processes. I measured resource properties (nutrients in sediment and water), non-resource properties (pH, alkalinity, sediment temperature, oxygen production), and biotic properties (periphyton biomass) in replicated outdoor monocultures of Stuckenia pectinata, Potamogeton nodosus, P. crispus, and Zannichellia palustris. After seven weeks, three of eight replicates of each species treatment were subjected to a temporary water draw-down that desiccated aboveground plant parts. The four species differed in their effects on ecosystem properties associated with nutrient uptake and photosynthetic activity. Shoot growth rate was negatively correlated with light transmittance to the sediment surface whereas root growth rate and root:shoot ratio were correlated with a species' ability to deplete nutrients in sediment interstitial water. Occupation of space in the water column was correlated with water alkalinity and pH and with sediment temperature. Root growth rate was related simultaneously to species effects on sediment nutrient dynamics and recovery of ecosystem properties after water draw-down. This suggests that this morphological trait may be used to predict the effects of environmental change on ecosystem functioning within the context of water level management. Expanding these analyses to more species, different environmental stressors, and across aquatic and terrestrial ecosystems should enhance predictions of the complex effects of global environmental change on ecosystem functioning.     

Spatio-temporal modeling of striped-bass egg, larval movement, and fate in the San Francisco Bay-Delta

Most models developed for the movement and fate of eggs and larvae of aquatic species are based on a particle tracking approach. Although this method has many advantages due to its high flexibility, particle tracking may become computationally intensive for complex geometries and when large numbers of particles are needed to simulate the population properly. In continuous models based on advection and dispersion mechanisms, the computational burden is independent of the size of the population. We developed a continuous fate and transport model for striped bass eggs and larvae in the San Francisco Bay-Delta. The model predicts the concentration of eggs and larvae at any location over time. The method of moments was used to account for the effect of temperature and age on the transition of eggs to larvae and larvae to juveniles. Egg and larval mortality were represented as functions of temperature, and eggs also experienced settling mortality. The fate and transport model used the same one-dimensional spatial grid as the existing Delta Simulation Model II (DSM2) hydrodynamics model. DSM2 output of flow rates, water depths, and cross-sectional areas were inputted into the fate and transport model to determine transport. The model was applied to striped bass eggs and larvae data collected during years 1990-1994; agreement between the modeled and the measured data was acceptable in most cases. Exploratory simulations were performed to demonstrate how the model could be used to evaluate the effects on egg and larval survival and total juvenile production of water diversions for supply and agricultural use and changes in the long-term mean water temperature. The model can be further used to examine the impact of various operation strategies in the San Francisco Bay-Delta, where diversion losses of early life stages of fishes remain a major management issue.     

沉积物再悬浮-重金属释放机制研究进展

水-沉积物界面重金属迁移和转化行为已成为水环境质量研究的热点。因自然、生物、人为活动等驱动的沉积物再悬浮使得沉积物颗粒吸附和结合的重金属可能通过吸附-解吸平衡和氧化还原反应而释放进入上覆水体。随着外在污染源输入逐步得到控制,沉积物再悬浮释放重金属将成为水体重要的内在污染源而对水环境质量和水生生物产生影响。本文综述了最近几年的相关研究文献,对沉积物再悬浮的动力来源及发生机制、再悬浮-重金属释放机制及主要影响因素进行了阐述,探讨了该领域未来可能的研究方向。相关研究发现,当干扰切应力大于沉积物的临界切应力值时,沉积物再悬浮发生,且再悬浮颗粒量随干扰切应力的增强而增大;再悬浮使还原态沉积物暴露于有氧环境,有机质和硫化物的氧化是沉积物结合态重金属释放的主要机理,而沉积物颗粒电性吸附的重金属则通过解吸进入水体;切应力大小、再悬浮水体理化性质、沉积物理化性质以及微生物活性等因素调控着沉积物吸附态或结合态重金属的释放。本文指出再悬浮沉积物释放重金属的去向（再分配机理）以及再悬浮-重金属释放的动力学过程、沉积物悬浮-重金属释放复合预测模型的建立、沉积物悬浮-释放重金属的生物可利用性及生物毒害评价将是本领域需要进一步研究的重点。     

Occurrence,distribution and risk assessment of abused drugs and their metabolites in a typical urban river in north China

We developed a method for determining 11 abused drugs in water and sediment. METH and EPH were the dominant drugs in water and sediment in Beiyunhe River. Abuse drugs in Beiyunhe River were mainly from hospitals and sewage effluents. Abused drugs in the water would not impair the aquatic ecosystem biologically. This study investigated the presence of 11 abused drugs and their metabolites, including amphetamine, methamphetamine (METH), ketamine, ephedrine (EPH), cocaine, benzoylecgonine, methadone, morphine, heroin, codeine, and methcathinone in the surface water and sediment samples of Beiyunhe River, a typical urban river flowing through Beijing, Tianjin, and Hebei provinces in North China. An analytical method of determining these abused drugs and their metabolites in water and sediment was developed and validated prior to sample collection in the study area. Results showed that METH and EPH were predominant in water and sediment samples. The total drug concentrations ranged from 26.6 to 183.0 ng/L in water and from 2.6 to 32.4 ng/g dry weight in sediment, and the drugs mainly originated from hospitals and sewage treatment plants. The average field-based sediment water distribution coefficients of abused drugs were calculated between 149.3 and 1214.0 L/kg and corrected by organic carbon. Quotient method was used to assess the risks. The findings revealed that these drugs and their metabolites at determined concentrations in water samples will not impair the aquatic ecosystem biologically, but their potential harmful effect on the function of the ecosystem and human health should not be overlooked.     

La在模拟水生态系统中的动力学行为

采用140La放射示踪技术,研究了稀土元素镧（La）在模拟水生态系统各组分中的迁移分布规律．并建立了相应的数学模型．结果表明,La在模拟水生态系统各组分中的积累率大小依次为：金鱼藻＞底泥＞螺蛳＞鱼,La在系统内的动态变化规律可用封闭分室模型来描述．     

外源洛克沙胂对水生态系统砷蓄积及底泥微生物生长的影响

为探明洛克沙胂(ROX)对水生态系统的毒性效应,采用模拟水生态系统,研究了外源添加不同浓度洛克沙胂(0、10、20、40、80和160 mg·L-1)对水生态系统砷含量及底泥微生物生长的影响。结果表明,水体及底泥砷含量随外源ROX用量增加而增加,但随暴露时间延长水体砷含量降低的同时底泥砷含量逐渐增加。金鱼藻和鲫鱼体内均出现明显砷蓄积现象,且160 mg·L-1ROX处理的水生态系统鲫鱼毒害效应明显,暴露1 d的死亡率为100%。金鱼藻对砷具有较强的富集能力,暴露32 d后砷富集量达398.1~1 538.91 mg·kg-1。不同浓度ROX对底泥真菌、细菌和反硝化细菌生长均具有不同程度的抑制效应,而对放线菌和氨化细菌生长具有一定的促进作用,且低浓度ROX(10 mg·L-1)对放线菌生长的促进作用明显。总体上,外源ROX进入水生态系统导致水体砷污染的同时在生物及非生物媒介中再次迁移、分配和蓄积,进而对鲫鱼及部分底泥微生物生长产生毒害。     

生物扰动对沉积物中污染物环境行为与生物可利用性的影响

疏水性有机污染物进入环境水体后易于与沉积物结合,对沉积物中的底栖动物造成危害。底栖动物引起的生物扰动作用可以通过改变沉积物的地球化学性质,对其中污染物的赋存形态、迁移转化和生物可利用性产生重要影响。在综述了国内外生物扰动影响沉积物中污染物环境行为和生物可利用性的最新研究进展基础上,重点讨论了沉积物颗粒交换、水体环境条件改变、疏水有机污染物解吸释放过程以及对生物扰动影响的定量化表征。最后对该研究方向进行了展望,指出应重点研究多种污染物及不同生物共存条件下的生态效应,以及造成沉积物扰动的影响因素的定量化表征等。     

Toxiwasp∗

TOXIWASP combines most of the kinetic structure of EXAMS 2 with the transport capabilities of WASP (Water Analysis Simulation Program). TOXIWASP uses variable chemical degradation rates from chemical properties and the environmental conditions of the aquatic ecosystem. These rates are reduced from pseudo first‐order rates to first‐order rates including the processes hydrolysis, biotransfor‐mation, phototransformation, oxidation, and volatilisation. Assuming ultimate local equilibrium, and using a chemical dependent partition coefficient as well as spatially varying environmental carbon fractions, sorption onto sediments and biomass is calculated. Environmental alternations could be specified in any time scale by providing monitoring data.

TOXIWASP generates total sediment and chemical concentrations every time step in every segment, including surface water, subsurface water, surface bed and subsurface bed. Advection, dispersion, mass loading, sedimentation, and scour affect sediment concentration in the water column and in the bed sediment concentrations depend on burial and erosion. In addition chemical concentrations are influenced by degradation, sediment‐water dispersion, and percolation. Lateral transport of chemical within the bed is neglected and transport data are not calculated in the program. TOXIWASP is developed to model stratified lakes, reservoirs, large rivers, estuaries, and coastal waters. As for EXAMS 2 (Burns et al.²) the TOXIWASP user has to accept the model's inability to connect the water body to a chemically contaminated atmosphere.