The Chemical Composition of Representative Arizona Waters Item Type text; Book Authors Smith, H. V.; Caster, A. B.; Fuller, W. H.; Breazale, E. L.; Draper, George Publisher College of Agriculture, University of Arizona (Tucson, AZ) Download date 01/10/2021 06:34:32 Link to Item http://hdl.handle.net/10150/212507 Bulletin 225 November 1949 1tuiurrMtj of Arizrnta &xtlitin DEPARTMENT OF AGRICULTURE THE CHEMICAL COMPOSITION OF REPRESENTATIVE ARIZONA WATERS Agricultural Experiment Station University of Arizona, Tucson ORGANIZATION Board of Regents Dan E. Garvey (ex officio) Governor of Arizona Marion L. Brooks, B.S., M.A. (ex officio) State Superintendent of Public Instruction W. R. Ellsworth, President Term Expires Jan., 1951 Samuel H. Morris, A.B., J.D Term Expires Jan., 1951 Cleon T. Knapp, LL.B Term Expires Jan., 1953 John M. Scott Term Expires Jan., 1953 Walter R. Bimson, Treasurer Term Expires Jan., 1955 Lynn M. Laney, B.S., J.D., Secretary Term Expires Jan., 1955 John G. Babbitt, B.S Term Expires Jan., 1957 Michaèl B. Hodges Term Expires Jan., 1957 James Byron McCormick, S.J.D., LLD President of the University Robert L. Nugent, Ph.D Vice -President of the University Experiment Station Staff Paul S. Burgess, Ph.D Director Ralph S. Hawkins, Ph.D Vice- Director Department of Agricultural Chemistry and Soils William T. McGeorge, M.S Agricultural Chemist Theophil F. Buehrer, Ph.D Physical Chemist Howard V. Smith, M.S Associate Agricultural Chemist Wallace H. Fuller, Ph.D Associate Biochemist George E. Draper, M.S Assistant Agricultural Chemist (Phoenix) Edward L. Breazeale, M.S Assistant Agricultural Chemist Logan Brimhall, B.S Assistant Agricultural Chemist (Phoenix) Bulletin 225 November 1949 litttvrrxstty of Arizona Vutir#tn DEPARTMENT OF AGRICULTURE THE CHEMICAL COMPOSITION OF REPRESENTATIVE ARIZONA WATERS Agricultural Experiment Station University of Arizona, Tucson TABLE OF CONTENTS Page INTRODUCTION 1 PRINCIPAL DRAINAGE AREAS IN ARIZONA 15 GENERAL ANALYSES OF ARIZONA WATERS 16 THE FLUORINE CONTENT OF CERTAIN ARIZONA WATERS 52 BORON CONTENT OF SELECTED ARIZONA WATERS 72 THE NITRATE CONTENT OF SELECTED ARIZONA WATERS 74 THE CHEPdIICAL COMPOSITION OF REPRESENTATIVE ARIZONA WATERS H.V. Smith, A.B. Caster, W.H. Fuller, E.L. Breazeale, and George Draper INTRODUCTION The water analyses given in this bulletin have been se- lected from a list of many thousand samples analyzed in the Agri - 1 cultural Experiment Station during the past twenty years. The analyses are being made available in this form to supply the de- mand for information on the quality of irrigation, municipal and domestic water supplies in the state. The waters are listed alphabetically according to the com- munity or town from which they were sampled. This method of ar- rangement, coupled with a listing according to location within river drainages (Fig. 1), makes the analyses easily accessible either by individual communities or by river drainages. ANALYTICAL METHODS The waters were analyzed for calcium and Magnesium by titra- tion with a standard soap solution. Chlorides were titrated with a standard silver nitrate solution. Sulfates were determined turbidimetrically after precipitation with barium chloride. Carbonates and bicarbonates were titrated with standard acid. Fluorine was determined by the Scott modification of the Sanchis method.Nitrates were determined by the phenol -disulfonic acid method and boron titrated with NaOH in the presence of mannite. Sodium was calculated by difference. Hardness was calculated as grains per gallon of calcium carbonate from the calcium and mag- nesium content of the waters.The sodium:calcium ratio was calculated by dividing the concentration of sodium by the calcium present. 1. Most of the waters reported here were submitted by well owners, members of the staff of the Experiment Station, the Extension Service, or the Soil Conservation Service. 2 Experiment Station Bulletin No. 225 INTERPRETATION AND SIGNIFICANCE OF ANALYSES Waters which may be considered to be good domestic waters may be very poor irrigation waters, so standards for each are 1 set up separately.According to McGeorge, the following values may be used in classifying domestic waters. DOMESTIC WATERS Desirable qualities in domestic waters are freedom from taste, freedom from excessive hardness, and freedom from an ex- cessive concentration of fluorine. Salt content: The presence of 700 to 1000 p.p.m. or more of salt in water makes the water unpalatable and therefore ob- jectionable to taste. For the normal individual there is no harm in drinking water containing 2000 p.p.m. of salts, al- though this is not to be recommended as a permanent practice. Hardness: Hardness is a quality imparted to waters by the presence of calcium and magnesium. Water which is hard due to calcium combined with bicarbonates can be softened by boiling. This is called "temporary hardness." When calcium is combined with sulfates, the resulting hardness is known as "permanent hardness." Such waters cannot be softened by boiling. Water which is temporarily or permanently hard may be softened by use of a zeolite softener or by other chemical means. The effi- ciency of some of the new detergents on the market is not affected by the hardness of the water. Degrees of hardness are expressed in the following table: 1. McGeorge, W;T.- Interpretation of Water Analyses. Univer- sity of Arizona, Extension Circular 107. 1940. Chemical Composition of Arizona Waters 3 TABLE 1.Relative Hardness of Waters Hardness Relative g.p.g. hardness 0.0 - 4.5 Soft 4.5 - 9.0 Fairly hard 9.0 + Hard Fluorine: The fluorine count of potable waters is very im- portant.Amounts up to 0.8 p.p.m. seem to harden the teeth and make them more resistant to decay. On the other hand, if chil- dren drink water containing möre than 0.8 p.p.m. during the time of formation of their permanent teeth, mottled enamel will result. The severity of mottling is dependent upon the amount present as shown in Table 2: LE 2. Severity of Mottled Enamel Produced by ..rying Amounts of Fluorine in Drinking Waterl Amount of fluorine Severity of p.p.m. mottling 0.0- 0.8 None 0.9- 1.3 Mild 1.4- 2.0 Moderate 2.1- 3.0 Moderately severe 3.1or over Severe Nitrates: In humid regions the presence of nitrates in water is indicative of pollution, but in arid regions their source may be nitrate mineral or from symbiotic or nonsymbiotic nitrogen fixation. It has been suggested that an excess of nitrates in water causes an incidence of "blue babies."This relationship has not been proved in Arizona where, in some in- stances, well waters are used which contain in excess of 300 p.p.m. of nitrates. 1. Smith, H.V. and Smith, M.C.Prevent Mottled Teeth. University of Arizona, Extension Folder W -43. 1945. 4 Experiment Station Bulletin No. 225 IRRIGATION WATERS A good irrigation water, from the standpoint of salt con- tent, is one which is low in salts.It is difficult to classify waters on the basis of salt content alone because the combina- tions of salt which occur are fully as important as the total amount present. Other factors, such as the kind of plant grown and the texture of the soil, must be considered when evaluating the quality of irrigation water. The United States Regional Salinity Laboratory, Riverside,California) has setup the fol- lowing criteria for quality based on salt content. TABLE 3. Quality of Irrigation Water Salt content p.p.m. Quality 0 - 600 Excellent to good 600 - 2000 Good to injurious over 2000 Injurious to unsatisfactory Calcium, magnesium and sodium: Hard waters are preferred over soft ones for irrigation. To be classed as suitable, waters should contain more calcium and magnesium than sodium. Such waters have a favorable effect upon the structure of the soil. If sodium predominates over calcium and magnesium, the water will have an adverse physical effect upon the soil. Structure, aeration, and water penetration will be poor and crop growth will be restricted. Table 4 relates the ratio of calcium and magnesium in water to the total bases present as a measure of their quality or suit- ability for use for irrigation. 1. Richards, L.A. The Diagnosis and Improvement of Saline and Alkali Soils. U.S. Regional Salinity Laboratory. 1947. Chemical Composition of Arizona Waters 5 TABLE 4. Quality of Irrigation Water Based on the Ratio of Calcium and Magnesium to Total Bases Ca + Mg % Na Quality More than 50% Less than 50% Satisfactory 35 - 50% 50 - 65% Doubtful Less than 35% More than 65% Poor With these values as a guide and knowing the texture of the soil as well as the crop to be grown, a fair appraisal of the quality of water may be made. Another method of calculating the quality of water from the standpoint of sodium and calcium content is to calculate the sodium:calcium ratio. In this bulletin the ratio is obtained by dividing the amount of sodium in parts per million by the parts per million of calcium present. A ratio greater than 1.0 indi- cates a preponderance of sodium and therefore an undesirable water. If the soil is well supplied with calcium which slowly becomes available, the sodium:calcium ratio might conceivably be greater than 1.0 without injury to the soil. Chlorides and sulfates: An unfavorable salt effect upon the plant is noted when water containing excessive amounts of chlorides and sulfates is used for irrigation. Sulfates are only about half as toxic as chlorides1 on the basis of equiva- lent concentrations expressed in p.p.m., but equally toxic in equal osmotic concentrations. Table 5 gives the range in concen- tration for these two ions permissible in each of the three grades of irrigation water.