Biofilms on the surface of gravels and aquatic plants in rivers and lakes with reusing reclaimed water

Reuse of reclaimed water for the eco-environmental water has become an effective measure to resolve the urban water crisis. However, it still contains large amounts of contaminants which may significantly affect the aquatic ecosystems. Biofilm attached on the surface of multiple matrixes in rivers and lakes is one of the indicators for describing the health of aquatic ecosystem. In this article, we chose eight rivers and lakes as the sampling locations, including three kinds of reclaimed water with different treatment processes and natural water. The morphology, structure and component characteristics of biofilms attached on the surface of aquatic plants and gravels in eight water bodies were evaluated. The results showed that the biofilm on the matrix surface were typical porous media with basic skeleton composed of inorganic particles, microorganisms and algae. The pores were filled with the viscous extracellular polymeric substances (EPS) secreted by microorganisms. The biofilms contained calcite, quartz, illite, alkali feldspar, dolomite, clinochlore, goethite and inorganic salt, and approximately 50 % of these compositions are calcite and quartz. The concentration of EPS was 20.78–500.44 μg/mL, and that of the gravel biofilms was less than that in aquatic plants by 18.1–75.3 %. In these three reclaimed waters, 4–7 kinds of PLFA (phospholipid fatty acid) were detected in aquatic plants biofilms, more than one or two kinds than in gravel biofilms. And the dominant PLFA were i15:0 and 18:0, the total contents of which were, respectively, 74.4, 62.9 and 85.9 % in the three kinds of reclaimed water. All biofilm samples contain major microorganisms such as Pseudomonas, Acinetobacter and Comamonas. This study is aimed to provide some support for assessing the health of river–lake ecosystem with biofilm indicator.     

Simultaneous sulfamethoxazole and trimethoprim removal and biofilm growth characteristics in attached growth bioreactor

Antibiotic contamination of aqueous environment due to pharmaceutical sewage may lead to development of antibiotic-resistant bacteria strain. In this research, elimination of antibiotics from synthetic wastewater was investigated. For this purpose, sulfamethoxazole and trimethoprim were treated by a pilot scale of net-like rotating biological contactor with three compartments, 48 plastic discs with total volume of 78.75 L. This system was continuously operated for about one year at various organic loading rates with different antibiotic dosages. The obtained results indicated that by increasing hydraulic retention time, the chemical oxygen demand (COD) removal was gradually increased. The optimal hydraulic retention time for desired rate of COD removal was 36 h. In addition, the effect of hydraulic retention time, organic load rate and sulfamethoxazole concentration in the removal of sulfamethoxazole and organic matter was assessed. Moreover, the results demonstrated that with increasing in organic load rate, sulfamethoxazole elimination was enhanced. In the next step, simultaneous removal of both antibiotics for constant inlet COD concentration of 8000 mg/L at optimum hydraulic retention time was analysed. The results showed that trimethoprim removal efficiency was approximately 100%, even at high concentration of trimethoprim (50 mg/L). For observation of dominant microorganism, samples of the developed biofilm on rotating biological contactor discs were scanned by scanning electron microscopy. In the first compartment where biomass was exposed to highest concentration of antibiotics, fungus strains were the dominant organism. In the second and third compartment antibiotic-resistant bacteria were the dominant attached living organisms.     

Adsorption and desorption characteristics of ammonium in eight loams irrigated with reclaimed wastewater from intensive hogpen

There are many reports of NO₃ ^? violating safety standards in the neighboring areas of concentrated animal feeding operations (CAFOs), which have become the bottleneck of the CAFOs development. The high concentration of ammonium nitrogen (NH₄ ⁺-N), which transforms into nitrate nitrogen (NO₃ ^?-N) through nitrification, and then leaches into the groundwater, is a potential threat to the environment. Adsorption and desorption characteristics of ammonium can reduce the amount of NH₄ ⁺-N in soils, which effectively prevents or slows down the nitrate leaching. Researches on the adsorption and desorption of ammonium mainly focus on the simple NH₄ ⁺ solution. Researches on the adsorption and desorption from hogpen wastewater are few, which is a complex system coexisting with many ions. In this paper, ammonium was selected as the object of pollutant, a batch of equilibration experiments was conducted to evaluate the adsorption–desorption and its kinetics in eight loams, typically found in Northern China, irrigated with original wastewater (OW) and reclaimed wastewater (RW) from intensive hogpen and a simple one consisting of clean water (CW). This study showed that the Freundlich and Langmuir model described the ammonium adsorption properties very well in multi-ion coexistensive system of hogpen wastewater; the ammonium adsorbed amount in the corresponding matrices followed by OW < RW < CW tendency, although the adsorption model parameters had great diversity. The adsorbed amount increased as the adsorption time went on and then approached to a stable state. CW had the shortest reaction time to reach equilibrium, whereas OW had the longest. The normal adsorption kinetics equation could not depict the adsorption behavior of loams but characterized by the ExpAssoc equation well. The study could provide references for the wastewater treatment and recycling, and rural water pollution controlling.     

典型工程筑坝砂砾料级配特征与压实特性研究

砂砾石坝坝料级配设计、坝体分区和填筑标准的设计均依赖于工程经验,为砂砾石坝坝料设计和填筑标准设计及评估提供工程类比基础。基于典型工程筑坝砂砾料级配包线和填筑标准现场试验干密度统计,分析实际工程筑坝砂砾料典型级配包线范围,给出关键级配特征参数的分布区间,并研究砂砾料级配特征对压实特性的影响。结果表明：（1）典型筑坝砂砾料级配最大粒径为400～600 mm,常见级配包线含砾量为70%～88%,曲率系数为1～10,不均匀系数多大于5,级配方程参数b和m范围分别为0～0.9和0.2～1.0;（2）能获得较高填筑干密度的砂砾料级配含砾量为70%～85%,曲率系数为1～10,不均匀系数大于5,级配方程参数b值和m值分别为0.7～0.9和0.6～0.9;（3）含砾量、曲率系数、不均匀系数和最大粒径对干密度均有显著影响,影响程度依次减小。     

The aquatic chemistry of rare earth elements in rivers and estuaries

Laboratory experiments were carried out to determine how pH, colloids and salinity control the fractionation of rare earth elements (REEs) in river and estuarine waters. By using natural waters as the reaction media (river water from the Connecticut, Hudson and Mississippi Rivers) geochemical reactions can be studied in isolation from the large temporal and spatial variability inherent in river and estuarine chemistry. Experiments, field studies and chemical models form a consistent picture whereby REE fractionation is controlled by surface/solution reactions. The concentration and fractionation of REEs dissolved in river waters are highly pH dependent. Higher pH results in lower concentrations and more fractionated composition relative to the crustal abundance. With increasing pH the order of REE adsorption onto river particle surfaces is LREEs > MREEs > HREEs. With decreasing pH, REEs are released from surfaces in the same order. Within the dissolved (<0.22 µm) pool of river waters, Fe-organic colloids are major carriers of REEs. Filtration through filters and ultrafilters with progressively finer pore sizes results in filtrates which are lower in absolute concentrations and more fractionated. The order of fractionation with respect to shale, HREEs > MREEs > LREEs, is most pronounced in the solution pool, defined here as <5K and <50K ultrafiltrates. Colloidal particles have shale-like REE compositions and are highly LREE enriched relative to the REE composition of the dissolved and solution pools. The addition of sea water to river water causes the coagulation of colloidal REEs within the dissolved pool. Fractionation accompanies coagulation with the order of sea water-induced removal being LREEs > MREEs > HREEs. While the large scale removal of dissolved river REEs in estuaries is well established, the release of dissolved REEs off river particles is a less studied process. Laboratory experiments show that there is both release and fractionation of REEs when river particles are leached with seawater. The order of sea water-induced release of dissolved REE(III) (LREEs > MREEs > HREEs) from Connecticut River particles is the same as that associated with lowering the pH and the same as that associated with colloidal particles. River waters, stripped of their colloidal particles by coagulation in estuaries, have highly evolved REE composition. That is, the solution pool of REEs in river waters are strongly HREE-enriched and are fractionated to the same extent as that of Atlantic surface seawater. This strengthens the conclusions of previous studies that the evolved REE composition of sea water is coupled to chemical weathering on the continents and reactions in estuaries. Moreover, the release of dissolved Nd from river particles to sea water may help to reconcile the incompatibility between the long oceanic residence times of Nd (7100 yr) and the inter-ocean variations of the Nd isotopic composition of sea water. Using new data on dissolved and particle phases of the Amazon and Mississippi Rivers, a comparison of field and laboratory experiments highlights key features of REE fractionation in major river systems. The dissolved pool of both rivers is highly fractionated (HREE enriched) with respect to the REE composition of their suspended particles. In addition, the dissolved pool of the Mississippi River has a large negative Ce-anomaly suggesting in-situ oxidation of Ce(III). One intriguing feature is the well developed maximum in the middle REE sector of the shale normalized patterns for the dissolved pool of Amazon River water. This feature might reflect competition between surface adsorption and solution complexation with carbonate and phosphate anions.     

青藏高原近25年来河流、湖泊的变迁及其影响因素

结合20世纪70年代中期的MSS图像和90年代末期的ETM 图像解译,对近25年来青藏高原河流、湖泊的分布现状及其变迁进行了分析。研究表明,青藏高原河流总体上变化不明显,部分地区外流水系个别河段略有摆动,内流水系少数河段发生改道、断流,入湖河流河口段发生延伸、退缩等变化。青藏高原多数天然湖泊变化较大,主要是部分湖泊面积缩小或扩大;少数湖泊解体或归并;有的已干涸的湖泊又重新汇水,有的湖泊则接近干涸。导致河流、湖泊演变的主要影响因素有气温变化、降水变化及冰川变化、气候雪线变化等。     

Response of Ruppia maritima to the reclaimed wastewater in coastal artificial landscape river

In recent years, reclaimed wastewater as a water source for urban artificial landscape rivers is being rapidly developed in some coastal cities with limited water resource available in China. However, eutrophication occurs more often in the landscape waterbody with reclaimed wastewater than in natural rivers and lakes. The study of restoration and reconstruction of macrophytes, especially the submerged aquatic vegetation, is essential to inhibit eutrophication of reclaimed wastewater. This study investigated the seasonal variation of biomass of Ruppia maritima in the artificial landscape river using reclaimed wastewater as the only water source in Tianjin, China. It was found that there were two seasonal growth peaks of Ruppia maritima each year in the coastal reclaimedwastewater. The contents of nitrogen and phosphorus of Ruppia maritima varied with the season.     

The environmental state of freshwater resources in Greece (rivers and lakes)

 The dominant factor regulating Greek riverine dissolved inorganic solid concentrations is chemical weathering, which depends on catchment climate and petrography. The majority of Greek rivers are moderately polluted and only a few of them show significant human impact and an increase in pollutant concentrations over time. Due to droughts in recent years and anthropogenic influence, the mean annual riverine dissolved solid concentrations exhibit a general interannual increase and significant long-term variations in their intra-annual hydrochemical fluctuations. The shallow Greek lakes are eutrophic, while the deep ones are oligo-mesotrophic. The majority of the lakes are monomictic and show summer thermal stratification, while the shallow ones are characterized by anoxic hypolimnetic conditions. Catchment petrography is not a dominant factor in the composition of lake waters since biochemical processes prevail. The majority of Greek lakes are also moderately polluted and are characterized by phosphorous-limited photosynthesis. Received: 17 March 1997 · Accepted: 16 January 1998     

基于GIS技术的岩体裂隙分形特征研究

基于GIS技术,对我国高放废物地质处置库预选区岩体裂隙测量数据进行可视化处理,计算反映岩体裂隙发育情况的分形特征参数,并应用于工程岩体质量评价。为岩体裂隙的定量化与模型化研究提供了新思路。     

A study on the physico-chemical speciation of heavy metals in waters of rivers, and lakes in the Changjiang River Valley, China

In the aquatic system, heavy metals always exist in a number of physico-chemical forms: particulate (Cp), soluble which consists of labile (MALI) and bound (inorganic MAb and organic MLb). The environmental behaviors of a metal are critically dependent on these forms. In this paper, the forms of heavy metals in waters from the Changjiang River source to mainstream and lakes were determined by ASV method. The main results are as follows: 1. The total contents (Ct) of Zn, Pb, Cu and Cd in the source were 4.0, 1.88, 1.28 and 0.07 (g/L) respectively, while Ct (g/L) in the mainstem were in the order of Zn (20.1) > Cu (14.9) > Pb (6.73) > Cd (0.15). Ct (g/L) in Dianchi Lake were Zn (7.2) > Pb (0.72) > Cu (0.53) > Cd (0.05), and in Poyang Lake were Zn (12.5) > Pb (4.2) > Cu (3.4) > Cd (0.05), and in Poyang Lake were Zn (12.5) > Pb (4.2) > Cu (3.4) > Cd (0.05). However, most of them were presented as Cp. Their dissolved contents (Cs, /L) were lower. 2. The distribution of soluble forms was related to the type of metal and to environmental variables. In general, Zn and Cd have a tendency to be present in MALi, Pb in MAb and Cu in MLb.     

中国跨境河流水化学特征及其控制因素

利用Gibbs图、三角图、非参数检验、主成分分析等方法对比研究中国主要跨境河流(雅鲁藏布江、怒江、澜沧江、伊犁河、额尔齐斯河、黑龙江、红河和狮泉河)的水化学特征, 探讨不同气候、岩性等条件下跨境河流河水中溶解性物质的主控因素及来源。结果表明: 河流pH范围为7.60±0.93~8.29±0.14, 呈弱碱性; 总溶解性固体(TDS)范围为139.14±106.58~238.03±85.47mg/L, 均高于世界河流平均值(100mg/L), 为弱矿化度水; 河水水化学组成中阳离子以Ca²⁺为主, 阴离子以HCO₃^-为主, 水化学类型为HCO₃^--Ca²⁺型。主要离子在河流间存在显著性差异, 对河流水化学而言, 岩性为第一级影响因子; 河水离子主要受碳酸与硫酸参与的碳酸盐矿物化学风化作用控制, 总体上, 碳酸盐岩以方解石的风化作用为主; 雅鲁藏布江、澜沧江、伊犁河、黑龙江和狮泉河水化学还受到人为活动影响; 主要离子浓度未超过中国生活饮用水标准及世界卫生组织推荐标准。本研究为后续跨境流域岩石化学风化引起的大气CO₂消耗这一地质碳汇提供依据。

     

大别造山带北缘中生代地层中榴辉岩砾石地球化学特征及构造意义

大别造山带北缘中生代地层凤凰台组和毛坦厂组中榴辉岩砾石的主元素、稀土元素以及微量元素具有如下特征,主元素中K2O富集(1．2l％),高∑REE(278μg／g),高(La／Yb)N(14．4)和大离子亲石元素(LILE,如Rb、Ba、K和Th等)富集。LILE明显富集,显著的Nb-Ta负异常槽,以及与原始地幔、N型大洋中脊玄武岩(N-MORB)相比,一些高场强元素(HFSE)相对于REE亏损,这些都支持榴辉岩砾石原岩的岛弧环境成因。在Th-Hf-Ta判别图上,榴辉岩砾石原岩属于火山弧玄武岩。推测原岩物质成分来源于地幔楔,在俯冲过程中并可能被海底沉积物所混染,所以富集了LILE。因此,榴辉岩砾石原岩可能形成于火山岛弧构造背景,同时也表明大别碰撞造山带在三叠纪陆-陆碰撞之前存在古岛弧发育阶段。根据地球化学特征特别是与稀土元素的比较,榴辉岩砾石与目前在大别造山带发现的榴辉岩有明显差别,因此后者可能不是前者的源区岩石。     

江湖地质环境演变中的武汉市堤防历史与城市发展

武汉位于长江与汉江交汇处,江、湖地质环境是造就武汉城市的基础,同时江河水患又是城市发展的主要制约因素。筑堤防洪是武汉城市建设的重中之重,武汉的城市发展史从某种程度上说就是堤防的修建史,是武汉城市发展的人地关系史。本文以武汉堤防修筑历史进程为主线,探讨了堤防建设的地质环境及对城市空间拓展和城市建设的意义。结果表明：修筑于北宋政和年间（公元1111 ~ 1118年）武昌的花蕊堤是武汉市最早的堤防,距今已有约900年的历史;明代以前为零星堤防建设阶段,主要为保护城廓安全,哪里遇险在哪里修堤,具有局部性、应对性特点。明代堤防兴建已带有很强的目的性和一定的系统性,特别是袁公堤的修建开启了武汉围垸发展的历史。清代是武汉堤防大发展时期,开始了较系统的堤防工程,奠定了武汉市堤防系统的基础,大量围垸的修建使武汉城市由沿河、沿江（天然堤）发展开始走向了内陆（围湖）发展的新阶段。民国时期,武汉市的堤防建设在清代的基础做了进一步的局部完善。武汉市的防洪堤防体系真正形成于新中国成立后的20世纪50年代,之后又不断地加固和加高,使之真正成为武汉市的安全保障工程;汉口的形成与发展完全依赖于堤防,城区的扩大大约经历了四个阶段,均是以四次堤防建设—袁公堤、汉口堡、京汉铁路堤、张公堤为前提的。堤防不仅是城市空间扩展的前提,又是城市建设的基础,民国以前武汉城区的主要街道大多数都依堤而建,平时以堤为街,汛期以街为堤,这是武汉城市建设和发展的显著特点。分别以袁公堤和张公堤为界,武汉堤防建设中的人地关系大致经历了三个阶段：“人类部分干预自然”维护生存阶段、“人为改造自然”谋求发展阶段和“人为控制自然”快速发展阶段。本研究可为地处洪泛区的城市地质调查提供借鉴。     

江湖地质环境演变中的武汉市堤防历史与城市发展

武汉位于长江与汉江交汇处,江、湖地质环境是造就武汉城市的基础,同时江河水患又是城市发展的主要制约因素.筑堤防洪是武汉城市建设的重中之重,武汉的城市发展史从某种程度上说就是堤防的修建史,是武汉城市发展的人地关系史.本文以武汉堤防修筑历史进程为主线,探讨了堤防建设的地质环境及对城市空间拓展和城市建设的意义.结果表明:修筑于...     

Behavior of mercury in an urban river and its accumulation in aquatic plants

The characteristics of mercury in the aquatic environment have been intensively studied in mining areas with heavy mercury pollution but little work has been conducted in urban areas, with no significant Hg source. This paper presents a study of the Haihe River, which flows through an urban area in North China. The concentrations of total mercury (THg) and methylmercury (MeHg) in the river water were 3.6–31.2 and 0.12–3.21 ng/l, and the corresponding values in river sediment were 22.9–374.8 and 0.03–0.46 μg/kg. These values are lower than the reported values from mining areas. The THg concentration in sediment samples collected from the urban areas was higher than that from the rural areas and the global background levels, indicating the influence of urbanization on mercury contamination. Samples of typical riparian and floating plants, reed and hornwort, were collected. Correlation analysis showed that sediment is the major source of THg and MeHg in reed and water is the major source of MeHg in hornwort. The higher bioaccumulation factor of reed indicates its higher potential to accumulate MeHg from the environment.     

喀斯特高原湖泊生物地球化学过程中的锌同位素特征

采用多接收电感耦合等离子体质谱仪(MC-ICP-MS)对喀斯特高原湖泊红枫湖、阿哈湖水体及其主要支流水体悬浮物和一些生物样品中的锌同位素进行了测定,测试精度小于0.11‰(2SD).结果显示,红枫湖水体与其主要支流水体悬浮物中的δ66Zn变化范围分别为-0.29‰～0.26‰和-0.04‰～0.48‰,阿哈湖水体与其主要支流水体悬浮物中的δ66Zn变化范围分别为-0.18‰～0.27‰和-0.179‰～0.46‰,均表现出支流中的锌同位素组成较重的特点.两湖生物样品中的δ66Zn变化范围较大,为-0.35‰～0.57‰,说明湖泊生态系统中各端员的锌同位素组成存在一定差异.根据同位素组成分析,湖泊主要入湖河流及所携带的陆源物质是阿哈湖泊水体中锌的主要来源,锌同位素是一种较好的物源示踪工具.红枫湖夏季δ66zn与Chla(叶绿素)呈显著的正相关(R=0.97),主要是藻类对锌的有机吸附和吸收过程导致锌同位素组成发生变化.此外,湖泊水体悬浮物中的锌同位素组成均在夏季较轻,表明大气的干湿沉降可能是一个较负的锌同位素源.水体悬浮物中的δ66Zn变化范围小于生物样品中的δ66Zn变化范围,说明由于生物作用过程导致的锌同位素分馏大于非生物过程.     

长江口湿地景观镶嵌结构演变的数量特征与分形分析

鉴于国内湿地研究对象大多为块状湿地,而对狭长形湿地鲜有研究,本文利用1990年和2003年遥感影像作为基本信息源,在GIS技术支持下,选取长江口狭长湿地,建立长江口湿地植被空间数据库.选取斑块大小、分维数、景观破碎度、景观多样性和优势度等指标, 研究区域景观的数量特征动态变化;运用分形理论建立各种景观类型形态的分形结构模型,以分维数为依据分析各种景观形态的复杂性;探讨控制和影响区域景观格局的主要因素.结果显示,1990~2003年期间,在自然与人为双重因素作用下该地区的湿地景观发生了显著变化,景观趋于破碎化,植物群落的演替由于人为的原因加速,一些地区景观呈自然变化趋势,一些地区由于围垦的原因,人为扰动大,呈现衰退趋势.     

Geochemical Characteristics and Implications of Eclogite Gravels from Mesozoic Strata at the Northern Margin of Dabie Orogenic Belt

The eclogite gravels, which were found in the Mesozoic Fenghuangtai and Maotanchang formations on the northern margin of the Dabie orogenic belt, are rich in K2O(1.21%),∑REE (278μg/g) ,and LILE(such as Rb, Ba, K, Th, etc.) , with high (La/Yb)N ratios(14.4),on the basis of the analyses of major elements, rare-earth elements (REE) and trace elements. Their enrichment in LILE, notable Nb-Ta depletion through, and depletion in HFSE relative to REE in comparison with the primitive mantle and N-MORB indicate that the protoliths of the eclogite gravels were formed in an island-arc setting. According to the Th-Hf-Ta discrimination diagram, the protoliths of the eclogite gravels are characterized by volcanic arc basalts.Trace element data indicate that the subducted marine sediments were assimilated in the magma chamber, resulting in the enrichment of LILE in the protoliths. Therefore, the protoliths of the eclogite gravels are considered to have been formed in an inland-arc setting, indicating that there had developed a paleo-inland arc before Triassic collision between the North and South China blocks in the Dabie orogenic belt. There is a marked difference between the eclogite gravels and the eclogites developed along the Dabie orngenic belt, solely based on their geochemical data,especially REE. Therefore, the eclogite gravels may not be derived from eclogite terrains preserved in the Dabie orogenic belt.     

河流潜流带地表-地下水过程对典型水生生物活动的响应研究进展

河流潜流带是地表-地下水连通和交换的主要区域,地表-地下水过程不仅促进了生源物质的迁移转化过程,还能涵养水源、稳定区域生境,为水生生物提供良好的栖息环境。因此掌握水生生物活动与地表-地下水交换关系是深刻认知和科学保护水生生态系统的关键。本文综述了前人有关水生生物活动反馈于地表-地下水交换过程的研究,例如,底栖微生物形成的生物膜可以吸收或滞留生源物质,改变迁移的时间和路径;水生动物的行为可能通过改变河床渗透系数和孔隙率等物理参数影响各类物质的地表-地下水交换通量;水生植物对水流的阻滞和扰动也会作用于地表-地下水交换过程。基于目前研究,本文提出了该领域的3个未来研究方向：潜流交换和水生生物互馈理论,水生生态功能与地表-地下水相互作用关系,河流潜流带生物-地球-化学耦合过程。