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Show Salt Lake City Watershed Management Plan ' 99 PHOSPHOROUS SOURCES AND FATE Slope and stream erosion of phosphorous bearing soils ( including top soils), and animal and human feces are sources of phosphorous for the canyon streams. Three types of phosphate are usually of interest: ortho, poly, and organic. Orthophosphates are available for immediate biological metabolism without further breakdowns. Polyphosphates include molecules with oxygen atoms and two or more phosphorous atoms. Polyphosphates undergo hydrolysis in aqueous solutions and revert to orthophosphate forms; however, the hydrolysis is typically slow. Organically bound phosphorous is generally not available for algae growth without anaerobic bacterial conversion. The major phosphorous removal processes in natural systems are chemical precipitation and adsorption while plants organically bind only small amounts. Phosphorous has a high tendency to bind with soil particles. Once it is bound, it is not likely to be readily released back into the environment. Orthophosphates are absorbed by clay minerals and certain organic fractions within the soil. Chemical precipitation with alum, iron, or aluminum also occurs, but at a slower rate. Sorption of phosphorous onto soils is the primary phosphorous removal process. TURBIDITY Turbidity is a measure of the suspended matter in water that interferes with the passage of light. Materials in the water that cause turbidity may range from small colloidal particles, to coarse dispersions. Much of the material that causes turbidity is inorganic matter, though a significant portion is also caused by organic matter. It is this organic matter that causes concern. The organic matter serves as food for bacterial colonies. As the colonies grow, additional turbidity is introduced. Some of these organics may also induce the growth of algae, meaning they may contain large amounts of nitrogen and phosphorous. Turbidity effects on water quality include: 1) Aesthetics, 2) Interference with filterability, and 3) Interference with disinfection. Aesthetically pleasing water instills confidence in the consumer that the water is pure and not polluted with wastes. As turbidity increases, the cost associated with filtering the water increases. Disinfection is impacted by turbidity also. If particles causing turbidity are in the water, then Page 15 |