Lake water

In Canada, ion-exchange (qv) technology has been used to produce potassium sulfate (4). Ion-exchange resins remove sulfate ions from lake water containing sodium sulfate. This is followed by a wash with aqueous solutions prepared from lower grade muriate of potash. High purity potassium sulfate is collected from the crystallizers into which the wash mns. 

Studies have appeared where photolysis in natural bodies of water under normal sunlight conditions has been examined. For example, metolachlor was slowly photodegraded by sunlight in lake water, with a half-life of 22 days in summer and 205 days in winter (28). Addition of a 5% solution of dissolved organic matter to the water extended the half-Hves two to three times longer, depending on the season (see PHOTOCHEMICAL TECHNOLOGY, photocatalysis). ... 

The selection of boiler-water treatment is also dependent on the type of cooling water. When cooling water reaches the boiler, various compounds precipitate before others. For instance, seawater contains considerable magnesium chloride. When the magnesium precipitates as the hydroxide, hydrochloric acid remains. In some lake waters, calcium carbonate is a significant impurity. When it reaches the boiler, carbon dioxide is driven off in the... 

Clarke (23) used many of the analyses from the program in his summary of the composition of river and lake waters of the United States. 

An accompanyiag effect of eutrophication that is more readily observable ia Table 1 is a decrease ia siUca coaceatratioa ia Lake Oatario. Some decliae ia dissolved siUca appareatiy has occurred ia all of the lakes except Lake Superior. This decliae is brought about by the growth of diatoms, a species of aquatic microorganisms ia the upper layers of lake water that is widespread ia all types of water impouadmeats where the water is clear and exposed to the sun. The siUca is used by these microorganisms to form their skeletons and is later precipitated and becomes part of the bed sediment. 

R. R. Weiler and V. K. Chawla, "Dissolved Mineral QuaHty of Great Lakes Waters," in Proceedings of the 12th Conference on Great Takes Research, Ann Arbor, Mich., International Association for Great Lakes Research, 1969, pp. 801—818. 

Copper has been employed as a bactericide, moUuscicide, and fungicide for a long time and is of importance in the control of schistosomiasis (see also Antiparasitic AGENTS, ANTHELMINTICS FUNGICIDES, AGRICULTURAL). Addition of copper to lake water acts as an efficient deterrent to transmittal of the disease by eliminating snails that act as hosts for the responsible parasite. Copper is commonly utilized at ca 0.1 mg/L as an algicide. In fresh water, acute toxicosis in fish is unusual if the copper concentration is below 0.025 mg/L (70) (see Poisons, economic). 

Environment Internal Untreated lake water intermittently chlorinated External Air... 

Sensitive Receptor Indicator a measurable physical, chemical, biological, or social (e.g., odor) characteristic of a sensitive receptor. For example, for the sensitive receptor. Crater Lake, water clarity is a sensitive receptor indicator. 

This section provides a general overview of the properties of lake systems and presents tlie basic tools needed for modeling of lake water quality. The priiiciptil physical features of a lake are length, depth (i.e., water level), area (both of the water surface and of tire drainage area), and volume. The relationship betw een the flow of a lake or reserv oir and the volume is also an important characteristic. The ratio of the volume to the (volumetric) flow represents tlie hydraulic retention time (i.e., the time it would take to empty out the lake or reservoir if all inputs of water to the lake ceased). This retention time is given by the ratio of the water body volume and tire volumetric flow rate. 

In experiments where Mono Lake water was acidified to remove carbonate and bicarbonate ions and again adjusted to pH 10, more than 90 percent of the soluble plutonium moved to the sediment phase. When carbonate ion concentration was restored, the plutonium returned to solution—strong evidence of the importance of inorganic carbon to solubility in that system(13). Early studies with Lake Michigan water, which has low DOC, had also implicated bicarbonate and carbonate as stabilizing ligands for plutonium at pH 8(14). This latter research characterized the soluble species as mainly anionic in character. 

The minimum mass concentration of oxygen required for fish life is 4 mg-L. (a) Assume the density of lake water to be... 

Carbonic acid is an important natural component of the environment because it is formed whenever carbon dioxide dissolves in lake water or seawater. In fact, the oceans provide one of the critical mechanisms for maintaining a constant concentration of carbon dioxide in the atmosphere. Carbonic acid takes part in two successive proton transfer equilibria ... 

Matheson, D.H. Elder, F.C., Eds. Atmospheric Contribution to the Chemistry of Lake Waters, J. Great Lakes Res., Suppliment 2, pp 225. National Academy of Science, Air Quality and Stationary Source Emission Control, Comm, on Nat. Resources, National Academy of Sciences, National Research Council, U.S. Gov t Print. Office, Washington, DC, 1975. Whelpdale, D.M. (Chair) Long-Range Transport of Air Pollutants A Summary Report of the Ad Hoc Committee, Atmospheric Environment Service, Environment Canada, Downsview, Ontario, 1976. 

Jeffries, D.S. Impact of acid rain on lake water quality. In Intermedia Pollutant Transport Allen, D.T., Cohen, Y., and Kaplan, I.R., Eds Plenum Press, 1989, New York, pp 41-53. 

Report on Great Lakes Water Quality, Report to the International Joint Commission by the Great Lakes Water Quality Board, Windsor, Ontario, 1987, 236p. 

Syers, J.K. Iskandar, I.K. Keeney, D.R. Distribution and Background Levels of Mercury in Sediment Cores from Selected Wisconsin Lakes. Water Air Soil Pollut. 1973 2, 105-118. 

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