Contamination of some reservoirs and lakes in Republic of Bulgaria by microcystins

This paper presents the results from analyses of water samples from 15 Bulgarian reservoirs and lakes for detection of microcystins presence by high‐performance liquid chromatography (HPLC) coupled to a ultraviolet (UV) and photo diode array (PDA) detector. In 3 of the studied drinking water reservoirs cyanobacterial blooms were not detected. Cyanobacterial blooms were observed in 6 of 12 investigated water bodies used for fishing and water sports. Microcystis was the dominant cyanobacterial genus. The concentration of total microcystins in the biomasses ranged from 8 to 1070 μg g^–1 (d.w.). Microcystin‐LR and microcystin‐RR were the predominant microcystins, followed by microcystin‐YR. Presence of dissolved microcystins was obtained in one water sample with concentration of total microcystins 1.64 μg L^–1. Presence of microcystin‐LF and ‐LW or unknown peaks possessing characteristic microcystin‐like UV‐spectra were not detected. Those first results for occurrence of microcystins in some Bulgarian reservoirs and lakes are a contribution to the knowledge on their distribution.     

Management information system of lakes and reservoirs

Information technologies provide a significant support in the management of lakes and reservoirs. Existing information systems mostly did not comprise all the necessary data and enabled collecting only a limited set of reports. More complex data analyses such as statistical analyses and data research were conducted in separate environments and recquired additional preparation of the data. Information system of lakes and reservoirs in Serbia (SeLaR) was produced in order to provide all the neccessary information for lake and reservoir management. The information system integrates a large data set and provide users with necessary information in the form of reports and charts. The users of the system are scientists and experts who study these issues, as well as students with the objective of continuous education. Furthermore, an interface was produced to enable linking with data research software. In this way a unique working environment was created to provide users with an efficient model of acquiring all the information necessary for the management and to find out new facts in data interaction, and also to make a forecast. This study presents an overview of the information system, its production model, the information available and the possibilities of data research.     

吉林省湖、库水质评估及其污染防治

湖、库富营养化是营养物质输入过程而引起的一种水效应。它不仅表现为水生植物和藻类的过度生长,同时还伴随着一系列的水质变化进而导致水质恶化,影响水体多种功能。本文以近年监测的主要湖、库的水质数据,采用主成分聚类分析和营养度评价方法对吉林省的主要湖、库的富营养化程度进行了分析与评价。这对区域水资源的合理开发利用,开展环境质量评价与预测,以及对制定湖、库富营养化防治对策具有重要意义。     

Near-bottom stratified currents and sediment transport in reservoirs and lakes

Results of field and theoretical studies of suspension transport by density currents are presented. The suspension transport is described by a mathematical model taking into account turbulent roiling and involvement, sedimentation, and bed erosion, variations in the vertical component of mean velocity, the relationship between the particles’ settling velocity and the distribution of their concentrations between the near-bottom and the overlaying water, on the one hand, and flow stability and velocity, on the other hand. The theoretical distributions of suspension concentrations are compared with those measured in 20 flows in nine reservoirs and lakes.     

湖库生态安全调控技术框架研究

针对湖库生态安全综合性调控技术缺乏的现状,为支撑和保障湖库型水体生态安全,开展了湖库生态安全调控概念、特征及技术需求分析,研究并系统构建了湖库生态安全调控技术框架(T-PIRLEP),阐述和分析了该框架的主要技术环节.根据研究结果,认为湖库生态安全具备可调控的特性,调控目的旨在维护以人类为终点的湖库生态环境和生态服务的安全.湖库生态安全调控具有综合性、功能导向性、类型差异性、空间异质性和不确定性的特征.基于T-PIRLEP的调控技术框架以湖库生态安全保障目标(T)为核心,以生态承载力为重要约束参考,从影响湖库生态安全状况的人口增长产业发展资源利用污染排放生态保护政策管理的耦合作用过程出发,采取以人口调控(P)、产业调控(I)、资源利用调控(R)、负荷控制(L)、生态调控(E)、政策调控(P)6类要素为主的调控措施来实现湖库生态安全调控.研究指出,调控过程需以湖库调控类型和其调控定位为引导,注重调控目标、调控措施、目标可达性分析之间的相互反馈,强化与生态安全评估研究的有机衔接.     

湖、库水体CH4冒泡排放研究进展

冒泡排放是湖、库水体CH₄排放的主要方式之一,其排放通量和占CH₄总排放量比例均具有极其显著的时空差异性,是当前水体CH₄排放估算不确定性的主要来源之一。然而,目前关于湖、库水体CH₄冒泡排放通量监测、时空分布规律、过程机制和模型模拟的系统梳理鲜有报道。本研究对比了目前水体CH₄冒泡的监测方法技术的适用性及优缺点,分析总结湖、库水体CH₄冒泡排放及通量的时空分布特征,梳理CH₄气泡在沉积物-水体中的产生-成长-迁移-释放的过程、影响因素及模型,并提出了水体CH₄冒泡过程模型框架。最后,本研究提出未来研究应基于湖、库水体分类、设备开发和改进来构建适应性的湖、库水体CH₄冒泡排放监测标准体系,开发基于过程的CH₄冒泡机理模型,为认识变化环境下湖、库水体CH₄冒泡过程和准确估算CH₄排放量提供支撑。     

Chemical methods of P-elimination in the tributaries of reservoirs and lakes

Based on experiences which have been gained at Wahnbachreservoir the success of chemical P-elimination in tributarie is described with regard to oligotrophication and subsequent improvement of the conditions for drinking water treatment. Presented at the International Conference on Lake Restoration at Zürich, 3–4 November 1986     

Modelling of water quality processes in lakes and reservoirs. II

ABSTRACT

The snowmelt runoff process from small basins is discussed. A differentiation is made between overland flow in the snowpack and groundwater flow induced by infiltrating meltwater. The effect of variations of the snowmelt intensity on streamflow is studied. It is shown that the runoff is high from the first day of snowmelt runoff if the streamflow is caused by overland flow, and that there are pronounced peaks every day, which almost correspond with the snowmelt intensity during daytime. Streamflow originating from groundwater, on the other hand, increases continuously during the snowmelt and shows only small daily peaks in the flow. Simultaneous overland and groundwater flow are also discussed. Observed runoff hydrographs from small basins are analysed in some detail. For the open fields studied the runoff shows the typical character of overland flow. For a rather large forested area the surface runoff also constitutes an important part of the runoff, but the groundwater baseflow is considerable.     

Modelling of water quality processes in lakes and reservoirs. III

Abstract

Digital mapping techniques are used increasingly in hydrology. One of the constraints on the application of those techniques is the digitizing process, which can be costly and time consuming. This paper describes the background and development of a low cost, easy-to-use system for digitizing maps, based on the use of a video camera as a scanner, and goes on to discuss the application of this system to the task of digitizing the hydrological soil maps of Europe.     

Effects of climate change on thermal properties of lakes and reservoirs, and possible implications

Meteorologic-driven processes exert large and diverse impacts on lakes’ internal heating, cooling, and mixing. Thus, continued global warming and climate change will affect lakes’ thermal properties, dynamics, and ecosystem. The impact of climate change on Lake Tahoe (in the states of California and Nevada in the United States) is investigated here, as a case study of climate change effects on the physical processes occurring within a lake. In the Tahoe basin, air temperature data show upward trends and streamflow trends indicate earlier snowmelt. Precipitation in the basin is shifting from snow to rain, and the frequency of intense rainfall events is increasing. In-lake water temperature records of the past 38 years (1970–2007) show that Lake Tahoe is warming at an average rate of 0.013°C/year. The future trends of weather variables, such as air temperature, precipitation, longwave radiation, downward shortwave radiation, and wind speed are estimated from predictions of three General Circulation Models (GCMs) for the period 2001–2100. Future trends of weather variables of each GCM are found to be different to those of the other GCMs. A series of simulation years into the future (2000–2040) is established using streamflows and associated loadings, and meteorologic data sets for the period 1994–2004. Future simulation years and trends of weather variables are selected so that: (1) future simulated warming trend would be consistent with the observed warming trend (0.013°C/year); and (2) future mixing pattern frequency would closely match with the historical mixing pattern frequency. Results of 40-year simulations show that the lake continues to become warmer and more stable, and mixing is reduced. Continued warming in the Tahoe has important implications for efforts towards managing biodiversity and maintaining clarity of the lake.     

Estimation of wind-forced internal seiche amplitudes in lakes and reservoirs, with data from British Columbia, Canada

Analyses of observations from four lakes in British Columbia, Canada, compare estimates of the amplitude of thermocline deflections to predictions of wind-driven internal seiche amplitudes made using the Wedderburn number,W. The study sites range from the 750 m diameter Brenda Mines pit-lake to the 107 km long Kootenay Lake. Causal filtering of the wind data with a frequency cut-off based on the fundamental baroclinic time-scale is critical for correct calculation ofW. With the filtering incorporated, good comparison betweenW, its integral equivalent the Lake numberL _N and the observations can be made. In all but the mine pit-lake, upwelling or near-upwelling conditions (W≈1) were encountered.     

Effects of lakes and reservoirs on annual river nitrogen,phosphorus, and sediment export in agricultural and forested landscapes

Recently, effects of lakes and reservoirs on river nutrient export have been incorporated into landscape biogeochemical models. Because annual export varies with precipitation, there is a need to examine the biogeochemical role of lakes and reservoirs over time frames that incorporate interannual variability in precipitation. We examined long‐term (~20 years) time series of river export (annual mass yield, Y, and flow‐weighted mean annual concentration, C) for total nitrogen (TN), total phosphorus (TP), and total suspended sediment (TSS) from 54 catchments in Wisconsin, USA. Catchments were classified as small agricultural, large agricultural, and forested by use of a cluster analysis, and these varied in lentic coverage (percentage of catchment lake or reservoir water that was connected to river network). Mean annual export and interannual variability (CV) of export (for both Y and C) were higher in agricultural catchments relative to forested catchments for TP, TN, and TSS. In both agricultural and forested settings, mean and maximum annual TN yields were lower in the presence of lakes and reservoirs, suggesting lentic denitrification or N burial. There was also evidence of long‐term lentic TP and TSS retention, especially when viewed in terms of maximum annual yield, suggesting sedimentation during high loading years. Lentic catchments had lower interannual variability in export. For TP and TSS, interannual variability in mass yield was often >50% higher than interannual variability in water yield, whereas TN variability more closely followed water (discharge) variability. Our results indicate that long‐term mass export through rivers depends on interacting terrestrial, aquatic, and meteorological factors in which the presence of lakes and reservoirs can reduce the magnitude of export, stabilize interannual variability in export, as well as introduce export time lags. Copyright © 2013 John Wiley & Sons, Ltd.     

Origins and effects of coagulation in lakes

A physical model for the transport and deposition of particles in lakes is formulated mathematically, solved numerically, compared with some field results available in the literature, and used to simulate the effects of coagulation and sedimentation in some limnetic systems. The results indicate that these processes exert significant and perhaps controlling effects on the transport and fate of particles and associated pollutants and nutrients in lakes.     

富营养化湖库天空地一体化监控平台系统设计与实践

湖泊和水库是我国的主要饮用水源地,但大都处于富营养化状态,蓝藻水华频发,已成为影响社会稳定、制约区域社会经济可持续发展的重大问题.蓝藻水华的整体应对策略,已经从被动应急转变为主动防御;但要做到主动防御,必须有现代化全方位的蓝藻灾害监测监控手段和体系,及时掌握蓝藻水华及其衍生灾害现状和动向,在未发生或者刚发生时及时觉察.本文针对富营养化湖库富营养化引起的蓝藻水华应急监控问题,按照"整个湖体、重点区域、关键位置"3个监测层次,利用中高分辨率卫星、无人机、岸基/平台视频、自动浮标、人工巡测等技术或手段,围绕"现状掌握、异常报警、原因追溯"的建设目标,提出了天-空-地一体化监控系统建设框架,明确了不同手段的协同方式和业务流程,并正在巢湖进行应用实践.相信本文提出的系统架构不仅在巢湖,在更多的富营养化湖库都具有重要的应用和推广价值.     

持久性有机污染物在中国湖库水体中的污染现状及分布特征

持久性有机污染物(POPs)在环境中广泛且持久存在,多数具有致畸、致癌、致突变等危害中国是全球湖泊密度较大的国家之一,湖泊在供水、渔业、维护生态系统多样性等众多方面发挥了重要作用湖泊是POPs的重要归宿之一湖泊水体中的POPs可被水生生物吸收利用并传递,对生态系统及人体健康构成较大危害因此湖泊水体中POPs的分布水平对周围的生态系统及人体健康有非常重要的影响本文收集、分析了2003年至2019年2月公开发表的80篇文献中的中国湖泊水体POPs数据,包括多环芳烃(PAHs)、六六六类农药(HCHs)、滴滴涕类农药(DDX)、多氯联苯(PCBs)、多溴联苯醚(PBDEs)、多氯联苯醚类(PCDEs)、全氟化合物(PFCs)及邻苯二甲酸酯类(PAEs),发现:目前中国已有水体POPs研究数据的湖泊共有49个,涉及19个省、直辖市、自治区,研究区域主要在东部地区(n=32),云贵高原(n=14)和青藏新疆湖区(n=3)少有研究,其它地区鲜有研究; PAHs、HCHs和DDX是研究最多的三类POPs,在中国湖泊水体中平均浓度分别为360.0±433.8 ng/L(n=26)、12.8±23.5 ...     

湖、库水体N2O排放研究进展

湖、库水体是重要的N₂O排放源,在全球氮素循环及全球气候变化中具有重要作用.本文综述了目前有关湖、库水体N₂O排放研究进展,重点介绍湖、库水体N₂O产生和排放的过程、不同时空尺度的排放特征、N₂O排放的影响因子框架及监测方法.湖、库水体N₂O不仅源于内部微生物硝化作用、反硝化作用、硝化-反硝化耦合作用、脱氮作用以及极少数底栖无脊椎动物代谢过程,同时流域上游河流汇入、地表径流输入、污水排放以及地下水排泄等构成湖、库水体N₂O的重要外源,但目前对内源/外源的相对贡献的定量化研究不足;湖、库水体N₂O排放方式包括扩散、植物传输及少量气泡排放,对水库而言,大坝下游水电涡轮机形成的脱气作用可能是N₂O排放的潜在途径.对文献综合分析表明,湖、库水体N₂O排放通常呈现明显的季节变化（夏季>冬季）和日变化,同时在全球（一般低纬度>高纬度）、区域及水体内部等不同尺度上表现出显著的空间变异性;这种时空变异特征主要受到湖、库自身理化因子（温度、营养盐、溶解氧、C/N、水文）、生物因子（水生植物、藻华）以及陆域人类活动（污水排放、农业活动以及城市化等）的影响;湖、库N₂O排放不同监测方法的差异也是潜在的影响因素,传统的漂浮箱法和薄边界层法均可能低估水体N₂O排放通量,未来需将传统的监测方法与新型的涡度相关法相结合,减小监测方法的不确定性.结合当前湖、库水体N₂O排放的研究不足,建议未来可以从湖、库N₂O产生的微生物机制,区域尺度上人类活动与湖、库群N₂O排放的耦合关系,水陆交错带的产、排过程,变化环境下的湖、库N₂O排放以及监测方法等方面深入研究.     

Damage to structures by pyroclastic flows and surges, inferred from nuclear weapons effects

In order to define the risk from explosive eruptions, one must constrain both the probability of explosive events and the effects, or consequences, of those events. This paper focuses on the effects of pyroclastic flows and surges (here termed ‘pyroclastic density currents', or PDCs) on buildings, infrastructure elements, and to some extent on vehicles. PDCs impart a lateral force to such structures in the form of dynamic pressure, which depends on the bulk density of the PDC (which in turn depends mainly on particle concentration) and its velocity. For reasonable ranges of particle concentration (10⁻³ to 0.5) and velocities (10 to 300 m/s), dynamic pressure on the upstream face of a structure ranges from 0.1 kPa to 10⁴ kPa. Lateral loads ranging up to about 100 kPa were produced during nuclear weapons tests in the 1940s and 1950s that were designed to study the effects of such loading on a variety of structures for civil defense and emergency response purposes in the event of nuclear war. Although considerable simplifications are involved, the data from these weapon tests provide useful analog information for understanding the effects of PDCs. I reviewed data from the nuclear tests, describing the expected damage from different loadings. Tables are provided that define the response of different structural elements (e.g., windows, framing, walls) and whole structures to loading in probabilistic terms, which in principle account for variations in construction quality, orientation, and other factors. Finally, damage documented from historical eruptions at Mt. Lamington (1951), Herculaneum (AD 79 Vesuvius eruption), and St. Pierre (1902 Mt. Pelee eruption) is reviewed. Damage patterns, combined with estimates of velocity, provide an independent estimate of particle concentration in the PDCs. Details of structural damage should be recorded and mapped around future eruptions in order to help refine this aspect of consequence analysis. Another fruitful approach would be to combine numerical simulations of eruption scenarios, which can produce simulated maps of dynamic pressure, with GIS-based data on structures for a given region; the result would be predictions of consequences that could be used for planning and emergency response training.     

Concentration and localization of hydroxylamine in the reservoirs and lakes in the territory of European Russia

Hydroxylamine concentration and localization in the Volga reservoir cascade and in the lakes of Yaroslavl province and Vladimir province were studied. It was found that, in microaerophilic zones of the most productive lakes, the rate of hydroxylamine formation is higher and its localization does not depend on the type of the limnological object (a reservoir or a lake), but is determined by the oxygen regime of the water body in question.