Oil components in the mouth area of the Don R. and in the Sea of Azov: Results of many-year studies

The data given are the results of many-year studying the distribution of the concentrations of main oil components (hydrocarbons, surfactants, and asphaltene-tarry substances) in the water mass, vertically settling particulate matter, and bottom sediment cores taken from the section Lower Don-The Gulf of Taganrog-Russian sector of the Sea of Azov in summer and autumn periods in 2006–2011. Spatial and seasonal regularities in the distributions of the total concentration of oil components and the values of their ratios in water, as well as the spatial and annual features of their accumulation in bottom sediments have been established. Radiological methods have been used for layer-by-layer dating of bottom sediment cores and determine the thickness of the layer that had formed under the maximal anthropogenic impact on ecosystems. The presence of considerable amounts of hydrocarbons of modern biological origin has been revealed in all components of examined aquatic complexes.     

The distribution and transformation of oil hydrocarbons in Onega Lake bottom sediments

The distribution of oil hydrocarbons in bottom sediments of Onega Lake was examined. Their qualitative and quantitative composition was examined by methods of IR-spectroscopy and chromatography-mass spectrometry. The background concentrations of oil hydrocarbons in bottom sediments are evaluated and the polluted area is determined. The major regularities in oil hydrocarbon transformations under natural conditions and anthropogenic impact are identified. The quantitative development of the bacterial groups that take part in the transformation of complex organic substances and oil product derivatives in the case of emergency pollution of Petrozavodsk Bay water area by oil products is demonstrated.     

The choice of oil-pollution criteria for organogenic bottom sediments by chromatography-mass-spectrometry

The results of studying the hydrocarbon composition of organogenic bottom sediments of oil-polluted lakes and lakes of similar types remote from centers of anthropogenic activity are given. To correctly assess the oil pollution of organogenic materials one has to take into account the presence of native hydrocarbons in their composition and to choose the main criterion of oil pollution based on the presence of specific oil components not characteristic of aquatic ecosystems in their natural state. The most promising among such components are alkylbenzenes С₁₅–С₂₅, which slowly degrade under the conditions typical of northern aquatic ecosystems and can be retained for a long time by organogenic matrix.     

Oil products in bottom sediments of water bodies in Khanty-Mansi Autonomous Okrug

Concentration of oil hydrocarbons in the bottom sediments of water bodies in Khanty-Mansi Autonomous Okrug has been analyzed. Statistical methods have been used to confirm the dependence of contamination level on the frequency of accidents in oil fields. Areas with heavily contaminated bottom sediments have been singled out.Translated from Vodnye Resursy, Vol. 32, No. 1, 2005, pp. 85–89.Original Russian Text Copyright © 2005 by Moskovchenko.     

Predicting the effects of sediment based internal nutrient loads on eutrophication in Kücükcekmece Lagoon for rehabilitation planning

In deep stratified coastal lagoons, hypoxic waters that result from phytoplankton decomposition in the stratified bottom waters are often associated with eutrophication. Decomposing biomass reaches the bottom sediments and enriches them with nutrients and organic matter. Nutrients trapped in sediments are released with time and promote excessive phytoplankton growth in the surface water. Because eutrophication in lentic ecosystems progresses in a self-fuelling cycle, outflow is the only available process for exporting excess nutrients to recover from eutrophication. Thus, rehabilitation of eutrophic coastal lagoons that have limited seawater interactions is a long term process. The importance of nutrient release from sediments on eutrophication and the delay effect of internal nutrient loading on the rehabilitation of a eutrophic coastal lagoon with limited seawater exchange were analysed in this study.An ecological model that couples the water column and the sediment diagenesis processes, was developed for water quality management purposes. Our findings indicate that the recovery of the Lagoon from eutrophication will be taken decades even in the absence of external nutrient loading. Therefore, we suggest applying rehabilitation strategies that control the nutrient fluxes from sediments for a faster recovery from heavily eutrophic conditions. Land-based nutrient sources must also be controlled because they feed water column and the bottom sediments with nutrients.     

Establishing and validation of a standard for oil content of bottom sediments in surface water bodies

Model experiments with oil-polluted bottom sediments and aquatic organisms (bacteria, protozoa, rooted plants, worms, maggots insects, mollusks, crustaceans, benthos-eating fish), whose life cycle is associated with the bed of water bodies, where used to establish the lethal, sublethal, and threshold concentrations, as well as the maximal allowable oil concentration in bottom sediments as a standard established basing on the response of most sensitive test-organisms. The established standard??0.02 g/kg absolutely dry bottom sediment??was validated in rivers of the Ob basin and approved as a regional standard for water bodies of Khanty-Mansi Autonomous Area (Yugra).     

Assessment of water and bottom sediment conditions in the bights of Koz’mina and Lake Vtoroe (Nakhodka Gulf,Peter the Great Bay,the Sea of Japan)

The state of the water area in the Bays of Koz’mina and Lake Vtoroe (Nakhodka Gulf is evaluated. The data given include water temperature and salinity, biochemical oxygen demand, pH, alkalinity, chlorophyll a, organic matter, biogenic elements, oil products, detergents, polycyclic aromatic hydrocarbons, phenols, and organochlorine pesticides in water and bottom sediments. Pollutants may enter the system of bights from both onshore sources and the open part of the bay. The water and bottom sediments in this part of the bay show higher values of BOD5 and the concentrations of oil products, polycyclic aromatic hydrocarbons, phenols, and organochlorine pesticides. The anthropogenic load on the water body is shown to increase because of the new industrial construction on its shore.     

Characteristic of oil pollution of the Sea of Azov and regularities in its dynamics

Oil pollution of water and bottom sediments (BS) of the Sea of Azov is characterized by using the results of studies carried out in different seasons of 1985–2005. Regularities in the dynamics of oil pollution are discussed and correlated with the stages in changes in the country’s economy.     

Physicochemical state and assessment of technogenic geochemical anomalies in bottom sediments of the Kyibyshev Reservoir near Ulyanovsk City

The results of studying physicochemical properties of bottom sediments in the Kuibyshev Reservoir are given. The evaluated characteristics include their porosity, specific surface area and density, and chemical state characteristics (pH, oil products, organic matter, phenols, and the mobile and total forms of heavy metals). Technogenic geochemical anomalies of bottom sediments are evaluated. The obtained results characterize the environmental state of bottom sediments in the study area.     

Effect of pore water of fine sediments on the ecological conditions of hydrosphere under oil-and-gas technogenesis conditions

Experimental models are used to study the poorly known function of pore waters, i.e., their role in hydrosphere pollution. This issue is studied as applied to modern bottom sediments, soil-forming grounds of the aeration zone, and impermeable clays in aquifers. The natural and technogenic geodynamic loads, accompanied by compaction and destruction of water-bearing rocks, are shown to intensify the processes of pore water pressing with the release of rock-forming elements, heavy metals, and organic substances into bottom water layers in water bodies, free soil or intermediate waters. This results in an environmental damage to water bodies, which could be used for drinking water supply and fishery. This study is of particular importance in areas of present-day oil and gas production.     

Aliphatic and polyaromatic hydrocarbons in bottom sediments of offshore mouth area of the Volga

Data on the concentration and composition of aliphatic and polyaromatic hydrocarbons in the surface layer and the body of bottom sediments in Volga delta and on the northern Caspian shelf are given. Volga delta sediments are shown to contain large concentrations of organic compounds. It is established that the concentrations of organic compounds is largely dependent on the dispersiveness of sediments. Anthropogenic hydrocarbons, both oil and pyrogenic, fail to pass the marginal filter of the Volga River and do not reach the open part of the sea. Therefore, the hydrocarbons contained in the bottom sediments on the Caspian Sea shelf are mostly of natural genesis. The distribution of organic compounds in the bottom sediment strata has a complex character. In some cases, their concentration increases because of the higher flux of hydrocarbons (especially, polyarenes in the 1950s).     

Space and time regularities in the distribution of dissolved and suspended manganese forms in Novosibirsk Reservoir water

The space and time regularities in the distribution, migration, and turnover of dissolved and suspended manganese forms in Novosibirsk Reservoir water are considered. The flux of dissolved manganese forms (Mn²⁺) from bottom sediments into the water mass is shown to reach its maximum in the under-ice period (since the late February to the mid-April), as well as in the period of maximal abundance of biota (August–early September), when reduction conditions form everywhere in reservoir bottom sediments. In this period, bottom sediments are the main source of manganese input into the reservoir water, their contribution reaching 250–400% relative to the inflowing river water; manganese vertical distribution in water is opposite to that of dissolved oxygen, and its concentration is in excess of the hygienic standards. The maximal flux of dissolved manganese forms (Mn⁴⁺) from water into bottom sediments is recorded in August–September (on the average, 0.17 g/(m² day)); it drops to 0.06 g/(m² day) during spring flood, and practically vanishes in the under-ice period.     

Concentrations of heavy metals in bottom sediments of Lake Dautkul as an indicator of anthropogenic impact in the area south of the Aral Sea

Data on the microelement composition of bottom sediment and water samples from Lake Dautkul for recent years are presented. Concentrations of more than 30 chemical elements are determined using instrumental neutron-activation analysis. This allowed the authors to reveal the regularities in the distribution and accumulation of chemical elements in water and bottom sediments. It is shown that bottom sediments exhibit a cumulative effect and prolonged activity, which adversely affect the aquatic medium and can serve an indicator of anthropogenic impact on the area under consideration.     

Analysis of the effect of copper-nickel works on the state of water resources in nearest features

The formation conditions of water exchange and quality in a lake used as a part of water disposal system of an operating copper-nickel metallurgical plant are considered. Water and material budget of the lake is calculated, including process water discharge, atmospheric precipitation, and snow melting. The quantitative and qualitative characteristics of bottom sediments and waters involved in lake water exchange are determined. The migration conditions of heavy metals from bottom sediments are evaluated and their dynamic layers are determined. Some measures are proposed for reducing the adverse impact of the coppernickel plant on water bodies.     

An oil spill-food chain interaction model for coastal waters

An oil spill-food chain interaction model, composed of a multiphase oil spill model (MOSM) and a food chain model, has been developed to assess the probable impacts of oil spills on several key marine organisms (phytoplankton, zooplankton, small fish, large fish and benthic invertebrates). The MOSM predicts oil slick thickness on the water surface; dissolved, emulsified and particulate oil concentrations in the water column; and dissolved and particulate oil concentrations in bed sediments. This model is used to predict the fate of oil spills and transport with respect to specific organic compounds, while the food chain model addresses the uptake of toxicant by marine organisms. The oil spill-food chain interaction model can be used to assess the environmental impacts of oil spills in marine ecosystems. The model is applied to the recent Evoikos-Orapin Global oil spill that occurred in the Singapore Strait.     

Pollution of bottom sediments in Petrozavodsk Bay of Lake Onega with oil products

The results of hydrochemical studies of Petrozavodsk Bay of Lake Onega carried out during 2001–2004 were analyzed. Due consideration was given to the pollution of bottom sediments with oil products and to the trend in pollution variations. The present condition of bottom sediments of the bay and the consequences of their pollution were assessed.     

Chemical composition of organic and mineral substances in silt bottom sediments of non-contaminated water bodies

Results of studying group and constituent composition of natural organic and mineral substances in silt bottom sediments of non-contaminated freshwater bodies are presented. The chemical composition of the investigated bottom sediments is shown to be complicated, diverse, and include products of autochthonous and allochthonous substance transformation. The necessity of further studying the concentrations of nutrients found in the bottom sediments of non-contaminated freshwater bodies, regarded as the “background” in estimating their environmental state, in studying processes occurring within water bodies, in determining natural and anthropogenic components of mineral and organic substances, as well as in estimating the balneologic value of the water bodies in question is substantiated.     

Assessment of bottom sediment contamination in acidified Karelian lakes

The physicochemical, toxicological, and teratological properties of bottom sediments in Karelian lakes (Vuontelenjarvi, Suojarvi, Venderskoe, and Chuchjarvi) and Kondopoga Bay of Lake Onega are studied. Bioassay results testify to a high toxicity of bottom sediments in heavily acidified lakes (with the water pH of 5.5 and lower).     

Toxicity assessment of bottom sediments in watercourses in Selenga River basin on the territory of Mongolia

Bioassay methods are used to assess the toxicity of bottom sediments in the main watercourses of the Selenga River basin and Lake Orog in Mongolia. Toxic bottom sediments are found in a brook in the region of the Erdenet Mining and Concentration Complex, as well as in the Eroo and Bukhlyn rivers, which experience the effect of intense gold mining. The conclusion is drawn that the Selenga River water flowing from the territory of Mongolia cannot directly affect the quality of water in Lake Baikal.     

Accumulation of Polychlorinated Biphenyls in the Sheksninskii Pool of the Rybinsk Reservoir

Specific features of polychlorinated biphenyl (PCB) distributions in bottom sediments, benthos, and fish of the Sheksninskii Pool of the Rybinsk Reservoir are discussed. It is shown that 95% of the total PCB is accumulated in bottom sediments. Mapping of PCB-polluted bottom sediments with allowance for the sediment type and bed relief is proposed. The obtained data along with coefficients of accumulation in the bottom sediments–benthos–fish chain were used to evaluate the maximum concentration of PCB in bottom sediments at which the environmental risk of fish metabolism disturbance will be minimum. It is shown that once the PCB discharge into the water body is completely eliminated, their presence in the system will still be an ecological hazard for 25–30 years.