Copper (II) Speciation in a Freshwater Ecosystem

Results of chemico-biological experiments in a natural water body with the use of model systems with Cu (II) introduced in them at different proportions of its chemical forms (natural and simulated) in the solution. The model forms used in the experiments were Cu complexes with benzyl- and hexadecylmalonic acids, simulating low-molecular dissolved organic substances. The experimental conditions were chosen based on a preliminary calculation using WATEQ–4f program. The complexes of Cu with hexadecylmalonic acid are found to be absorbed by suspensions and removed into bottom sediment more actively than other Cu forms. The toxicity of introduced Cu for the phyto- and zooplanktonic communities is found to depend on the concentration of Cu²⁺ aqua-ions in the solution, in the presence of which the higher concentrations of complexes with malonic acids do not exert their toxic effect.     

Numerical Modeling of Ice Jams

A numerical model is proposed to describe the formation of ice jams under the effect of a release wave.     

Study of Heavy Metal Compound Transformations in Surface Waters

Results of studying Fe(III) hydrolysis and sorption of heavy metal compounds by organic matter of bottom sediments are discussed. The rate of Fe(III) hydrolysis is found to be largely determined by the concentration of dissolved organic substances. Values of kinetic parameters are obtained for heavy metal compounds sorption under static and dynamic conditions. Calculating the solubility of Fe, Cu, Cd, Zn, and Pb sulfides allowed the assessment of the amount of metals lost by bottom sediments due to the formation of metal complexes with dissolved organic substances contained in natural waters.     

Geographical and Ecological Characteristics of the Caspian Sea and Modern Tendencies in the Evolution of Its Ecosystem

The Caspian Sea is characterized in the geographic and ecological aspects, and the state of its ecosystem is estimated. The natural and anthropogenic processes that control the formation of the environmental conditions in the Caspian Sea and the distribution of principal commercial hydrobionts and their food items are analyzed. Data on modern tendencies in changes in the abiotic and biotic parameters of the ecosystem, their causes and mechanisms are summarized. Prospects of further changes related to the development of shelf fields of petroleum hydrocarbons are assessed.     

The State of Benthic Communities and Water Quality Evaluation in the Cheboksary Reservoir

Present-day quantitative and qualitative characteristics of the Cheboksary Reservoir have been investigated, and data on the biological diversity of benthic organisms have been compared to those of hydrobiological studies carried out in the region prior to the reservoir construction. The reservoir bottom communities include 75 species and forms of benthos. The reservoir water quality has been evaluated using different methods, including the determination of the degree of morphological structure abnormalities in chironomid larvae, regarded as sublethal indicators of bottom sediment pollution with toxic substances.     

Carbon-Oxidizing and Sulfate-Reducing Bacteria in Mozhaisk Reservoir Soils

The population and distribution of carbon-oxidizing and sulfate-reducing bacteria in the soils of the Mozhaisk Reservoir are studied.     

Nutrient Transport into the White Sea with River Runoff

Averaged data from long-term observations of concentrations of mineral-nutrient fractions along with fragmentary data and indirect estimates of organic-component concentrations in the tributaries of the sea (the Niva, the Onega, the Northern Dvina, the Mezen, and the Kem rivers) are analyzed. Monthly variations in the concentrations of the major nutrients in the river water flowing into the sea are characterized, and relationships between them in different seasons are determined. Annual nutrient transport into the White Sea by river water is assessed based on characteristics of river runoff and nutrient concentrations using a mathematical model. Wide variations are established in the ratios of organic and mineral fractions of nutrients delivered into the sea. The shares of mineral components in the total runoff of N_tot and P_tot into the sea are found to be equal to 18.1 and 18.8%, respectively.     

On the Problem of Differential Payment for the Use of Different-Quality Surface Waters in Ukraine

The evolution of views and practical decisions regarding the problem of collecting payment for the use of surface waters with regard to their quality in the former USSR and present-day Ukraine is discussed. A simple and feasible method is proposed for differentitation of regional (basin) rates of payment for the use of surface water in Ukraine with allowance made for its quality assessed based on a system of environmental classifications.     

In-plane and anti-plane strong shaking of soil systems and structures

The concept of in-plane and anti-plane shaking is introduced with a rigid block on a plane surface with Coulomb friction. Using a hypoplastic constitutive relation to model the mechanical behaviour of the soil, numerical solutions for a rigid block on a thin dry or saturated soil layer are obtained. The coupled nature of dynamic problems involving granular materials is shown, i.e. the motion of the block changes the soil state—skeleton stresses and density—which in turn affects the block motion. Motions of the block as well as soil response can be more realistically calculated by the new model. The same constitutive equation is applied to the numerical simulation of the propagation of plane waves in homogeneous and layered level soil deposits induced by a wave coming from below. Experiments with a novel laminar shake box as well as real seismic records from well-documented sites during strong earthquakes are used to verify the adequacy of the hypoplasticity-based numerical model for the prediction of soil response during strong earthquakes. The response of a homogeneous earth dam subjected to in-plane and anti-plane shaking is investigated numerically. In-plane and anti-plane shaking is shown to cause nearly the same spreading of a sand dam under drained conditions, whereas under undrained conditions anti-plane shaking causes stronger spreading of the dam. The dynamic behaviour of a breakwater founded on rockfill and soft clay during the 1995 Kobe earthquake is back-calculated to show the good performance of the proposed numerical model also with a structure. Section 9 deals with buildings on mattresses of densified cohesionless soils or fine-grained soils with granular columns, slopes with ‘hidden’ dams and structures on piles traversing clayey slopes to show the suitability of hypoplasticity-based models for the earthquake-resistant design and safety assessment of geotechnical systems.