Field Simulation of Cadmium Pollution of a Freshwater Body

An experiment in mesocosms installed in a fish-rearing pond was used to adequately simulate the character of self-purification, migration, and the redistribution of cadmium and its chemical forms in major components of a freshwater ecosystem, into which this chemical is imported in concentrations far in excess of its MAC. The major portion of the imported cadmium was found to be removed from the water mass within a few days, mostly, as a component of particulate matter settling onto the bed, including dead plankton remains, as ion-exchange cadmium forms adsorbed by suspension (37%), and as forms associated with ferromanganese oxides (41%). The rate of cadmium removal from the water mass is determined both by the amount of particulate matter settling onto the bed and the efficiency of cadmium sorption by it, depending on the acid–alkaline and redox conditions in the water body.     

Influence of the Grain Size Composition of Bottom Sediments in Lake Baikal on the Distribution of Methane and Sulfide Sulfur

Lithology and Mineral Resources - Based on the study of separate areas of Lake Baikal (depth from 14 to 250 m), influence of the grain size composition of bottom sediments on the distribution of...     

Wave Dynamics of River Water Quality

Doklady Earth Sciences - A cyclic wave nature of variations in the composition and properties of river water, indicating the long-term memory effect in the corresponding time series, has been...     

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...     

Computing the methane cycle elements in the aquatic ecosystems of the Sea of Azov and the World Ocean based on empirical formulae

Empirical relationships between methane concentration and the rates of its oxidation and emission in the sediment-water-atmosphere system are computed using the experimental data and the data presented in the literature. For the Sea of Azov and the World Ocean the possibility is demonstrated of using the empirically derived formulae to compute the methane cycle elements in aquatic ecosystems. The comparability of methane volumes in the water column and bottom sediments as well as of those oxidized and released from water and sediments computed using these formulae, demonstrates the adequacy of the obtained formulae. It is shown that depending on morphological parameters of reservoirs of aquatic ecosystems and on their volume and area, the ratio of the amounts of methane that is oxidized and released to the atmosphere, changes as well as the rate of its turnover.     

Variations in Methane Concentrations in the Water of the Don River and Taganrog Bay under the Effect of Natural Factors

Seasonal and diurnal variations in CH₄ concentration in the water of the Don River and Taganrog Bay are examined, and two maximums are recognized in the seasonal variations. The diurnal variations are shown to be affected by the meteorological conditions.