Characteristics of mining tremors within the near-wave field zone

Mining in the Upper Silesian Coal Basin, Poland, induces tremors with magnitudes ranging up to 4.3. The recordings of mining tremors from the near-wave fiel and the far-wave field show different characteristics of ground motion.Knowledge of these characrteristics, has an enormous practical importance when solving the problems of resistance of underground workings against seismic impacts. The near-wave field is characterized by a domination of the high frequency components of motion, and the seismograms often are a single pulse Geomechanical interpretation of them leads to the conclusion that this pulse corresponds to a single exciting force. This fact is also reflected in the rockbursts: the potentially damaging ground motion which is restricted to the seismic source region.The seismometric data have shown that the peak particle velocities from a hypocentral distance of 200–300 m, resulted in more than 3 cm/s. The peak ground velocities appear to be dependent on stress drop , and peak particle velocities reaching 5 m/s may occur. The computational example proves that in a thick coal seam the pulse with the stress =1.8 MPa from the tremor at the short source distance can generate the rockburst.     

Identification of petroleum pollution sources of water bodies and streams

A three-level scheme is proposed for the identification of sources of fresh and old petroleum pollution of water bodies and streams, including an optimal complex of simple, available, and highly effective physicochemical techniques, criteria, and sample processing methods ensuring the reliability of conclusions derived from them. The efficiency of application of the proposed methods is illustrated in several water bodies and streams (the Bol’shaya Krepkaya, Tuzlov, Chitinka, and other rivers), which have experienced oil pollution.     

The role of biogenic hydrocarbons in the assessment of oil pollution of freshwater bodies

The results of studying the concentrations and component composition of hydrocarbons and associated oxidized hydrophobic compounds in water bodies with different degrees of oil product pollution are given. It is shown that the role of biogenic hydrocarbons in the assessment of oil pollution of freshwater bodies, especially those having high biological productivity, can be quite significant. Such assessment requires the examination of their genesis by using the proposed gas-chromatographic and luminescent criteria. The most informative object for observations in the identification of oil and biogenic hydrocarbons for the assessment of chronic oil pollution of freshwater bodies is bottom sediment.     

Optimum operation of restoration techniques for eutrophic water bodies

Operating rules have been applied in water resources management for a long time in order to control and supply a requiredquantity (volume) of water. The operating rules have to guarantee the optimum management of the reservoir(s). Thequality of the stored water has been satisfactory for the desired utilization up to the sixties. Due to the deterioration of reservoir water quality through human impacts, however, increased attention had to be paid since. Eutrophication of stagnant waters is still an unsolved problem. Through means of various restoration techniques, i.e., dilution/flushing or hypolimnetic withdrawal, the quality of the stored water can be improved. Continuous operation or appropriate time or depth variant operating rules are required to achieve this goal. The paper presents such rules for long-term operation. They have been established for the first time and can he represented in two or three-dimensional graphs depending on the number of included components (e.g., actual water storage and quality). The quality operating rules take into account the dynamics of the processes in aquatic ecosystems. Simplifications with regard to application and acceptance (e.g., clarity) are developed and tested. The general validity and efficiency of the operating rules have been proved in a case study (a multi-purpose reservoir) and a fictitious lake.     

Numerical approaches to solid-state convection in planetary bodies

Numerical methods suitable for the calculation of finite-amplitude thermal convection in planetary interiors are reviewed. Three methods of approach are described and compared; namely, finite-difference, finite-element and spectral procedures. Application of each approach to three-dimensional solid-state convection with complex rheology is examined. Finite-difference methods have enjoyed some success to date. However, future developments are likely to favor finite-element methods when rheology and boundaries are complex, and spectral methods when accuracy is paramount and rheology and boundaries are simple.     

Artificial recharge efficiency assessment by soil water balance and modelling approaches in a multi-layered vadose zone in a dry region

To assess recharge through floodwater spreading, three wells, approx. 30 m deep, were dug in a 35-year-old basin in southern Iran. Hydraulic parameters of the layers were measured. One well was equipped with pre-calibrated time domain reflectometry (TDR) sensors. The soil moisture was measured continuously before and after events. Rainfall, ponding depth and the duration of the flooding events were also measured. Recharge was assessed by the soil water balance method, and by calibrated (inverse solution) HYDRUS-1D. The results show that the 15 wetting front was interrupted at a layer with fine soil accumulation over a coarse layer at the depth of approx. 4 m. This seemed to occur due to fingering flow. Estimation of recharge by the soil water balance and modelling approaches showed a downward water flux of 55 and 57% of impounded floodwater, respectively.     

Estimating water fluxes in the critical zone using water stable isotope approaches in the Groundnut and Ferlo basins of Senegal

Sustainable water management in semi-arid agriculture practices requires quantitative knowledge of water fluxes within the soil-vegetation-atmosphere system. Therefore, we used stable-isotope approaches to evaluate evaporation (E_a), transpiration (T_a), and groundwater recharge (R) at sites in Senegal's Groundnut basin and Ferlo Valley pasture region during the pre-monsoon, monsoon, and post-monsoon seasons of 2021. The approaches were based upon (i) the isothermal evaporation model (for quantifying E_a); (ii) water and isotope mass balances (to partition E_a and T_a for groundnut and pasture); and (iii) the piston displacement method (for estimating R). E_a losses derived from the isothermal evaporation model corresponded primarily to Stage II evaporation, and ranged from 0.02 to 0.09 mm d⁻¹ in the Groundnut basin, versus 0.02–0.11 mm d⁻¹ in Ferlo. At the groundnut site, E_a rates ranged from 0.01 to 0.69 mm d⁻¹; T_a was in the range 0.55–2.29 mm d⁻¹; and the T_a/ET_a ratio was 74%–90%. At the pasture site, the ranges were 0.02–0.39 mm d⁻¹ for E_a; 0.9–1.69 mm d⁻¹ for T_a; and 62–90% for T_a/ET_a. The ET_a value derived for the groundnut site via the isotope approach was similar to those from eddy covariance measurements, and also to the results from the previous validated HYDRUS-1D model. However, the HYDRUS-1D model gave a lower T_a/ET_a ratio (23.2%). The computed groundwater recharge for the groundnut site amounted to less than 2% of the local annual precipitation. Recommendations are made regarding protocols for preventing changes to isotopic compositions of water in samples that are collected in remote arid regions, but must be analysed days later. The article ends with suggestions for studies to follow up on evidence that local aquifers are being recharged via preferential pathways.     

北方三省区部分水体冰下水生维管束植物研究

迄今为止,在北方冬季冰下仅发现有菹草、聚草、黄丝草、金鱼藻及扇叶水毛莨等几种水生维管束植物存活,其生物量力10—3500g/m~2,依其单位面积鲜重大小顺次为菹草、聚草、黄丝草、金鱼藻、扇叶水毛莨。明暗瓶试验结果表明冰下各水草光台毛产氧量变动于0.039-3.610mg O_2/d·g(草)之间,以菹草产氧量最大,其后顺次为扇叶水毛莨、聚草、金鱼藻。     

Comparative hydrochemical assessment of the current state of some water bodies in the Upper Volga

Results of field studies of water chemistry in the Upper Volga and some its tributaries in the reach between the Volga source and Tver City, as well as in lakes Sterzh, Vselug, Peno, and Volgo, which are constituent parts of the Verkhnevolzhskoe Reservoir, as well as Selizharovskii Pool of Lake Seliger. The year-to-year and season-to-season dynamics of the hydrochemical regime of the examined water bodies and their variations downstream the Volga under the effect of natural and anthropogenic factors are analyzed.     

乌梁素海水体汞的分布特征及污染风险评估

于2011年1月采集乌梁素海表层水样,对湖水中重金属Hg含量进行分析.结合Hg的空间分布特征,利用单因子指数综合污染评价指数与健康风险评价模型对Hg污染程度与风险进行评估.结果表明,乌梁素海表层水体中Hg的平均浓度为1.04μg/L,所有监测点Hg的含量都超出地表水Ⅲ类标准和国家渔业用水标准,50%的监测点超出了地表水Ⅳ类标准.水体中Hg的分布模式与流域排污口位置、入湖口及水动力条件有一定关系,高值区域分布在入湖口相对集中的西北与东北部,湖泊南部与出口处的含量相对较低,处于中等水平.乌梁素海湖水中Hg的非致癌性污染物所致的健康危害风险度介于0.75×10-9~2.15×10-9a-1之间,Hg所致的健康危害风险度的贡献率在71.43%~92.44%之间,表明Hg污染水平与健康风险都较高,应该给予特别关注.     

Convection in large bodies of water open to the atmosphere

Abstract

Convection in large bodies of water open to the atmosphere is studied as a two-layer system, which allows for the accurate modeling of the interfacial boundary conditions. The Biot number associated with the heat transfer across the interface becomes a result of the analysis rather than a condition. The linear and nonlinear analyses yield essentially the same stability results, providing a sharp stability limit.     

A semiempirical mathematical model of the secondary pollution of water bodies by soluble iron and manganese forms

A semiempirical mathematical model of iron and manganese migration from bottom sediments into the water mass of water bodies has been proposed based on some basic regularities in the geochemistry of those elements. The entry of dissolved forms of iron and manganese under aeration conditions is assumed negligible. When dissolved-oxygen concentration is <0.5 mg/L, the elements start releasing from bottom sediments, their release rate reaching its maximum under anoxic conditions. The fluxes of dissolved iron and manganese (Me) from bottom sediments into the water mass (J _Me) are governed by the gradients of their concentrations in diffusion water sublayer adjacent to sediment surface and having an average thickness of h = 0.025 cm: \({J_{Me}} = - {D_{Me}}\frac{{{C_{Me\left( {ss} \right)}} - {C_{Me\left( w \right)}}}}{h}\) (D _Me ≈ 1 × 10^–9 m²/s is molecular diffusion coefficient of component Me in solution; C _Me(ss) and C _Me(w) ≈ 0 are Me concentrations on sediment surface, i.e., on the bottom boundary of the diffusion water sublayer, and in the water mass, i.e., on the upper boundary of the diffusion water sublayer). The value of depends on water saturation with dissolved oxygen (\({\eta _{{O_2}}}\)) in accordance with the empiric relationship \({C_{Me\left( {ss} \right)}} = \frac{{C_{_{Me\left( {ss} \right)}}^{\max }}}{{1 + k{\eta _{{O_2}}}}}\) (k is a constant factor equal to 300 for iron and 100 for manganese; C _Me(ss) ^max is the maximal concentration of Me on the bottom boundary of the diffusion water sublayer with C _Fe(ss) ^max ≈ 200 μM (11 mg/L), and C _Mn(ss) ^max ≈ 100 μM (5.5 mg/L).     

New approaches to integrated quality assessment of lakeshores

The EU Water Framework Directive (WFD) requires the ecological assessment of water bodies. Since the littoral zones and the lakeshores are part of lakes as water bodies as defined by the WFD, a new scheme for ecological quality assessment of lakeshores should be established. It is proposed that this scheme should go beyond the formal requirements of the WFD, as it includes aspects of nature conservancy, landscape protection, and regional planning and development. Some of these aspects are subject to other EU legislation (e.g. Habitats Directive) and some are subject to national legislation. Ten general Quality Elements (QEs) are proposed, which can be refined and reified through several levels of detail, depending on the specific aims of a study. A list of eleven topics, which should be discussed in the establishment of the lakeshore quality assessment scheme, is given. The more complex ones are the implementation of other EU legislation, the definition of lakeshore types and reference conditions, the stipulation of best aggregation procedures, and a better understanding of the significance of hydrological and morphological impacts on the biota.     

Oil pollution in the Persian Gulf and approaches, 1978

Vessel reports of oil slicks in the Persian Gulf and approaches during 1978 show an increase in number and percentage of positive reports towards the Strait of Hormuz. Pronounced seasonal variations in slick characteristics include an increase in number, size and areal coverage during winter, but an increase in thickness of slicks in summer. High solar radiation enhances photolysis, evaporation, solution and bacterial degradation of oil. Slick dispersal patterns agreed with prevailing wind and surface current circulation. Most slicks appeared to represent separate events. Of the ten major slicks, which were all ‘thin’, seven were reported by two out of 84 vessels. Collectively, they contained 73% of all oil in 139 reported slicks. Using an average of 13 μm for the thickness of ‘thin’ slicks, the largest slick contained more than 54 000 m³, and all slicks combined totaled 160 000 m³. Two independent alternate estimates confirm this computation within 10%.     

太湖流域太浦河周边区域突发水污染潜在风险评估

太浦河是太湖流域重要跨省界河流,沿岸区域污染源众多,下游分布重要水源地,存在突发水污染潜在风险,迫切需要开展区域污染源潜在风险评估,为突发水污染事件的风险防控提供科学依据.本研究通过太浦河周边区域的污染源调研,明确污染源的空间分布与污染源强,确定评估区域的主要污染物（化学需氧量、氨氮、锑、重金属铬、油品、危险化学品）,综合考虑污染源、河流水文、沿岸社会经济等因素,筛选突发水污染潜在风险评估指标,构建评估指标体系,评估突发水污染事件的综合风险,识别太浦河周边区域的主要突发水污染潜在风险源.研究结果表明：太浦河周边区域的高突发水污染风险区呈现片状或斑块状分布,主要包括大型污水处理厂区域、大型工业企业区域、加油站和危险化学品仓库集中分布区、太浦河沿岸工业企业区域、水源地周边工业企业区域,总面积为22 km²,占太浦河污染源风险评估范围总面积的1.4%,是突发水污染事件防控的重点区域.     

Concerning the occurrence of water in the planetary bodies

The study of the cosmic chemical abundance of the elements suggests that water (which is a combination of the first and second most abundant chemically active elements) is likely to be the most abundant chemical compound in the solar system.It is found that water indeed appears to be a common constituent of planetary bodies even though its presence is not always directly detectable. The amount involved, and the form it takes, varies from one object to another. The Earth has surface liquid water and crustal hydrate materials and only Mars of the terrestrial planets is also likely to have non-atmospheric water and that in frozen form near the surface. The mantles of the icy satellites, and particularly those of Jupiter and Saturn, are the most extended locations of water in the solar system although Uranus and Neptune are likely to have substantial mid-mantle internal water components. Only Mercury and Moon appear to be devoid of water. The smaller bodies such as comets are excluded from the discussion even though they are now known to be composed largely of water-ice.     

Comparative analysis of two approaches to the assessment of water quality by biological indices: Case Study Of Dnieper tributaries

Water quality in several tributaries of the Dnepr in the southeastern part of its basin in the territory of the Republic of Belarus was estimated by six biotic indices and by the comparison with reference sites as accepted in the European Water Framework Directive. Water quality estimates obtained by different indices for the same sites are significantly different. The most adequate estimates were obtained from the British and Belgian indices for the assessment of the state of flowing waters. The comparative analysis of the two approaches showed that the method based on reference sites yields a more stringent estimate of river water quality than biotic indices.     

Integrating long-term water and sediment pollution data, in assessing chemical status within the European Water Framework Directive

The European Water Framework Directive (WFD) establishes a framework for the protection and improvement of estuarine (transitional) and coastal waters, attempting to achieve good water status by 2015; this includes, within the assessment, biological and chemical elements. The European Commission has proposed a list of priority dangerous substances (including metals such as Cd, Hg, Ni and Pb), with the corresponding list of environmental quality standards (EQS), to assess chemical status, but only for waters. In this contribution, a long-term (1995–2007) dataset of transitional and coastal water and sediment trace elements concentrations, from the Basque Country (northern Spain), has been used to investigate the response of these systems to water treatment programmes. Moreover, the approach proposed in the WFD, for assessing water chemical status (the ‘one out, all out’ approach), is compared with the integration of water and sediment data, into a unique assessment. For this exercise, background levels are used as reference conditions, identifying the boundary between high and good chemical status. EQS are used as the boundary between good and moderate chemical status. This contribution reveals that the first approach can lead to misclassification, with the second approach representing the pattern shown by the long-term data trends. Finally, the management implications, using each approach are discussed.     

Sulfate reduction in natural water bodies: 2. Empirical models for process rate assessment

Empirical models that are used to assess sulfate reduction rates in the aquatic environment and bottom sediments of water bodies are discussed. Such models, with different detail, take into account the effect of the major habitat factors (the concentrations of organic matter, its components, and sulfates; ambient temperature; the numbers and activity of sulfate-reducing bacteria) on matter oxidation transformation during the sulfate reduction process. Improvements in the empirical models are proposed with the aim to more adequately account for the effect of environmental factors on the sulfate reduction rate distribution in water bodies. Validation of such models and the assessment of their parameters are demonstrated against available observational data collected at appropriate water bodies.