Abstract

Water is chiefly used for domestic purposes, for irrigation and in industry. Yet, the same quality of water will not meet all purposes. The total solids should not exceed 500 ppm. for a water of good chemical quality for drinking purposes (U. S. Public Health Service Drinking Water Standards, 1946). Among the ions, bicarbonate is preferable to carbonate, sulphate and chloride, and calcium to sodium. For industrial purposes, waters containing calcium and magnesium salts are undesirable because such waters cause boiler-scale and corrosion of the material. Irrigation water is usually judged by three criteria; (a) horon atom concentration, (b) the ratio of sodium ion content to the sum of sodium, magnesium, calcium and potassium ions and (c) total dissolved salts. The following table gives the permissible limits for total solids and percent sodium of several classes of irrigation water as generally adopted in the U. S. A. (1).

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