Methane in Water and Bottom Sediments of Lake Baikal

Water Resources - The distribution of methane concentration measured in 2014 and 2015 in different parts of Lake Baikal has been analyzed. In the period of expedition studies, methane concentration...     

Regional Retrospective Analysis of Water and Bottom Sediments in the Upper Volga

Water Resources - The dynamics of water quality in the Upper Volga was analyzed in the segment from the source to the Ivankovo Reservoir. It was found that the increase in anthropogenic stress in...     

Heavy Metals in the Water and Bottom Sediments of the Selenga River Delta

The overall concentration of Cu, Pb, Zn, Cr, Mn, and Fe are determined in the water and bottom sediments of the Selenga River delta. The concentration of Cu, Pb, and Zn is found to decrease in the lower course of the river, at the delta outlet. The concentration of Mn and Fe is found to decrease in the downstream direction from the river's upper course along the investigated delta arms, whereas the concentration of Zn and Cr in certain arms exceeds their concentration in the upper section of the delta.     

Physicochemical Properties of Bottom Sediments in Water Bodies in the Central and Southern Vietnam

Water Resources - The physicochemical characteristics of bottom sediments in inland water bodies in the Central and Southern Vietnam are presented for the first time, including particle-size...     

The environmental and biotic impact of the oil spill in Kerch Strait in November 2007

The effect of an emergency oil spill in Kerch Strait in November 2007 on the environment and biota in the southern Sea of Azov is analyzed based on the material of integrated expedition studies carried out by the Southern Scientific Center, RAS, before and after shipwrecks and during monitoring within a year after the emergency.     

Rating Water Quality in Sevastopol Bay by the Fluxes of Pollutant Deposition in Bottom Sediments

Sevastopol Bay is used as an example for the development of criteria for rating anthropogenic impact by elimination fluxes from the water area of post-Chernobyl (⁹⁰Sr, ¹³⁷Cs, ^239,240Pu) and natural (²¹⁰Pо) radionuclides, as well as mercury and organochlorine compounds. The differentiation of the bay water area into zones with different biogeochemical conditions and the balance approach to interpreting field observation data were used to assess the conditioning capacity of Sevastopol Bay ecosystem for conservative radioactive and chemical substances by elimination fluxes of pollutants into aqueous depot, which is the open part of the Black Sea and into the geological depot, i.e., its bottom sediment stratum.     

Bottom Sediments of the Caspian Sea as an Indicator of Changes in Its Water Regime

Qualitative changes in the Caspian Sea water regime for the last 20–25 kyr are analyzed based on studying the particle-size distribution, the composition of clay minerals, the mineral composition of the coarse clastic fraction, and the magnetic susceptibility of deep-sea bottom sediments.     

Oil Products in Bottom Sediments of Freshwater Bodies

The specific features of freshwater bodies are shown to facilitate the accumulation of oil products in bottom deposits. The oil product components are found to be represented by hydrocarbons and tars. The latter component can account for more than 50% of their total. The extent of bottom deposits pollution by oil products is assessed for a number of freshwater bodies in Russia.     

Contamination and Sources Identification of Polycyclic Aromatic Hydrocarbons in Water and Sediments of Annaba Bay Basin,Algeria

Water Resources - Annaba gulf is a coastal area (southwestern Mediterranean Sea) that receives large diffuse inputs from Fertial plant, Seybouse wadi and Boujemaâ wadi, which are influenced by...     

Heavy Metals in the Ivan'kovo Reservoir Bottom Sediments

Spatial and temporal variability of heavy metals concentrations in the Ivan'kovo Reservoir bottom sediments was studied. It was found that for the period of 1983–1998, their content largely decreased in many sections of the reservoir, with the exception of individual deep-water channel stretches and certain bays. The character of vertical distribution of microelements in the bottom sediments is shown to be related to the level of contamination and character and rate of water exchange in the reservoir.     

Persistent Organic Pollutants in Barents Sea Bottom Sediments

Water Resources - Long-term observation data (2003–2018) of 625 stations were analyzed to determine the distribution of organochlorine pesticides (DDT, hexachlorobenzene, and...     

Hydrocarbons in the Suspension and Sediments of the Baltic Sea

The article gives the results of studying the concentration and composition of aliphatic and polycyclic aromatic hydrocarbons in suspension in surface waters at sections from the English Channel and Skagerak Strait to various regions of the Baltic Sea (2010–2015) and in water and bottom sediments of the southeastern part of the sea in the water area of the Kravtsovskoe field (2008–2015). In recent years, the surface waters of open areas of the Baltic Sea showed a decrease in hydrocarbon concentrations down to background levels (12–33 μg/L). The maximal concentration of hydrocarbons (in excess of the MAC) was recorded in different seasons in navigation areas, including the English Channel and Pregola R. mouth. In the zone of the Kravtsovskoe field, the concentration and composition of hydrocarbons in water depends on their inflow from the bank, and the same characteristics in bottom sediments, on the rate of their leakage from sediment stratum. A decline in these processes have led to a decrease in hydrocarbon concentrations in the sediments of a local area near D-6 platform to background levels (5–7 μg/g) and to the predominance of terrigenous, rather than petroleum, alkanes in hydrocarbon compositions.     

Structural Variations of Bottom Sediments in the Rybinsk Reservoir

Long-standing variations in the structure of bottom sediments within typical habitats of the aquatic life are characterized using the Volzhskii Pool of the Rybinsk Reservoir as an example. The role of hydrodynamic processes of the littoral zone in the formation of the ground complex of shallow water areas of the pool is discussed. The trends in variation in the quality of bottom substrate in fish habitats are analyzed. The peculiarities of long-standing variations in the distribution of types of bottom sediments in the entire reservoir are shown.     

Microbial Activity of Bottom Sediments in a Stabilization Pond

The Pond of Dvorec, used for a final treatment of waste waters and at the same time for fish breeding, has been observed working in an assimilation and later on in a stabilization mode (SVOBODA and KOUBEK) . The data on the chemical composition and microbiological properties of its sediments are given. A comparative analysis of the stabilization pond sediments and the sediments of the second stabilization pond have shown a high purification function. An influence of temperature, aeration and thickness of the layer upon a microbial activity and a release of the substance into the water environment were verified in laboratory experiments. A higher layer of sediments can, above all at increased temperatures, negatively influence the water quality for fish breeding. After composting the drawn pond sediments can be recommended for the fertilization of an agricultural land in near surroundings.     

Some Environmental Consequences of Soil Dumping in the Black Sea as a Result of Dredging Operations in Kerch Strait

The results of monitoring performed by Southern Research Institute of Marine Fisheries and Oceanography (YugNIRO) in 1990–1998 in the course of dredging operations with dumping in the Black Sea of soils dredged in Kerch Strait are analyzed. The study covered the soil physical properties and particle size distribution; the extent of the soil pollution by heavy metals, oil products, and organochlorine compounds; the amounts of such pollutants delivered into the sea with these soils; the extent of pollution of water and bottom sediment in the zone of soil dumping offshore Kerch Strait. The amounts of pollutants entering the Black Sea as a result of soil dumping are compared with those entering the sea from other pollutant sources, and the extent of environmental pollution in the dumping zone is compared with the background level of the sea pollution. The admissible rates of soil dumping are estimated, and potential consequences of this process are predicted.     

Stratification of Horizons in Bottom Sediments of the Rybinsk Reservoir

Physical properties of cores taken from sediments in the channel zone of the Volga Stretch in the Rybinsk Reservoir are studied. The physical properties of the sediments are shown to be related to the evolution of geomorphological processes and the amount of organic matter in the sediment. Variations in the physical properties were used to recognize synchronous formation of sediment horizons corresponding to certain formation stages of the reservoir soil complex and anomalous environmental and climatic events. Three stages of channel sedimentation are established based on characteristic behavior of magnetic parameters and organic matter content. The magnetic parameters of sediments are shown to allow data reconstruction on some environmental and hydrological processes.     

Chemistry and Toxicity of Bottom Sediments in Small Watercourses of St. Petersburg

Water Resources - The article gives the results of integrated studies of bottom sediments in four watercourses in the central St. Petersburg: the rivers of Ekateringofka, Okhta, Fontanka, and...     

Sulfite-Reducing Clostridia and their Participation in Methane and Hydrogen Sulfide Formation in the Bottom Sediments of Water Objects and Streams of the ETR South

Water Resources - The article discusses the role of sulfite-reducing clostridia in methane and hydrogen oxide formation in bottom sediments. The examined materials have been accumulated in the...     

Environmental Effects of the Bottom Sediments of the Senezh Reservoir

The formation and accumulation of bottom sediments in the Senezh Reservoir are discussed on the basis of field observations. Data on the bottom sediment thickness, the rates of accumulation, and the concentrations of organic substances, metals, petroleum products, and organic pollutants are presented. The bottom sediments of the reservoir are demonstrated to be still no source of secondary pollution.     

Core Sampler for Soft Bottom Sediments with Lower Closing Mechanism

A novel sediment core sampler is represented. It is suitable for liquid sediments and for undisturbed sediment cores with a large core diameter from shallow and deep waters.