TAILE I-1 CONTINUED t 00
Constituent
or property Source or cause Effects
Specific conductance Mineral content of the water. Indicates degree of mineralization. Specific conductance is a meas, (micromhos at 25C00) ure of the capacity of the water to conduct an electric current.
Varies with concentration and degree of ionization of the constituents.
Hydrogen ion Acids, acid-generating salts, A pH of 7.0 indicates neutrality of a solution. Values higher than concentration (pH) and free carbon dioxide lower 7.0 denote increasing alkalinity; values lower than 7.0 indicate the pH. Carbonates, bicarbon- increasing acidity. pH is a measure of the activity of the hydrogen ates, hydroxides, and phos- ions. Corrosiveness of water generally increases with decreasing phates, silicates, and borates pH. However, excessively alkaline waters may also attack metals. raise the pH.
Color Yellow to brown color of some Water for domestic and some industrial uses should be free from waters is usually caused by perceptible color. Color in water is objectionable in food and organic matter extracted from beverage processing and many manufacturing processes. The leaves, roots, and other or- USPHS (1962) states that color should not exceed 15 units in ganic substances. Objection- drinking water. 0 able color in water also results M from industrial waste and sewage. Hydrogen sulfide Probably the reduction of sul- Causes "rotten-egg" odor and causes corrosion. Limits of tolerance o (H.S) fates to sulfides by organic are generally less than 0.5 ppm. Since hydrogen sulfide is a gas material under anaerobic con- it is easily removed from water by aeration. ditions in deep wells. In
some cases, it may be derived
from the anaerobic reduction
of organic matter with which
the water comes in contact.