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Chemical Character
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Chemical Character of WaterThe chemical character of the ground waters in Chase County is shown by the 34 analyses of water given in parts per million in Table 7. Factors for converting parts per million of mineral constituents to equivalents per million are given in Table 8. These water samples were collected from wells distributed as evenly as practicable within the county and among the principal water-bearing formations. Table 7 includes analyses of the two public water supplies. The samples of water were analyzed by Howard A. Stoltenberg, Chemist, in the Water and Sewage Laboratory of the Kansas State Board of Health.Table 8--Factors for converting parts per million of mineral constituents to equivalents per million.
Total Dissolved Solids When water is evaporated, the residue consists mainly of the dissolved mineral constituents and usually a little water of crystallization. Waters containing less than 500 parts per million of dissolved solids generally are satisfactory for domestic use, except for difficulties resulting from their hardness or occasional excessive content of iron. Waters containing more than 1,000 parts per million may include enough of certain constituents to produce a noticeable taste or to make the water unsuitable in some other respect. The amount of dissolved solids in the 34 samples of ground water collected in Chase County is indicated in Table 9.Table 9--Dissolved solids in water samples from wells and springs in Chase County.
Hardness Hardness of water is the property that generally receives the most attention and in washing is recognized by the increased quantity of soap required to produce lather. Calcium and magnesium are the constituents that cause practically all the hardness of water and are the active agents in the formation of the greater part of the scale formed in steam boilers and in other vessels in which water is heated or evaporated.In addition to the total hardness, the table of analyses shows the carbonate hardness and the noncarbonate hardness. The carbonate hardness is due to the presence of calcium and magnesium bicarbonate and can be removed almost entirely by boiling. This type of hardness is sometimes called temporary hardness. The noncarbonate hardness is due to the presence of sulfates or chlorides of calcium and magnesium; it cannot be removed by boiling and is sometimes called permanent hardness. So far as use with soaps is concerned, there is no difference between the carbonate and noncarbonate hardness. Noncarbonate hardness generally forms harder scale in steam boilers. Water having a hardness of less than 50 parts per million generally is rated as soft, and its treatment for the removal of hardness under ordinary circumstances is not necessary. Hardness between 50 and 150 parts per million does not seriously interfere with the use of water for most purposes; however, it does appreciably increase the consumption of soap. The use of water in the upper part of this range of hardness will result in the formation of a considerable amount of scale in steam boilers. Hardness above 150 parts per million can be noticed by anyone, and if the hardness is 200 or 300 parts per million or more it is common practice to soften the water for household use or to install cisterns to collect soft rain water. Where municipal water supplies are softened, the hardness generally is reduced to 60 or 80 parts per million. The additional improvement from further softening of a whole public supply generally is not deemed worth the increase in cost. The hardness of 34 water samples of ground water collected in Chase County is indicated in Table 10. Table 10--Hardness of water samples from wells and springs in Chase County.
Iron Next to hardness, iron is the constituent of natural waters that in general receives the most attention. The quantity of iron in ground waters may differ greatly from place to place, even in waters from the same formation. If a water contains much more than 0.1 part per million of iron, the excess may precipitate as a reddish sediment. Iron, where present in sufficient quantity to give a disagreeable taste and to stain cooking utensils, may be removed from most waters by simple aeration and filtration, but a few waters must be treated by the addition of lime or by passing the water through resinous substances having a high affinity for iron.Table 11 shows the iron content of the water samples analyzed. Table 11--Iron content of water samples from wells and springs in Chase County.
Fluoride Although the quantities of fluoride are generally much less than the quantities of other constituents of natural water, it is desirable to know the amount of fluoride present in water that is likely to be used by children. Fluoride in water has been shown to be associated with the dental defect known as mottled enamel, which may appear on the teeth of children who, during the period of formation of the permanent teeth, drink water containing fluoride. It has been stated that waters containing 1.5 parts per million or more of fluoride are likely to produce mottled enamel (Dean, 1936). If water contains as much as 4 parts per million of fluoride, 90 percent of the children drinking the water are likely to have mottled enamel, and 35 percent or more of the cases will be classified as moderate or worse.Recent investigations indicate that small quantities of fluoride in water are beneficial for the development of teeth, and that the incidence of tooth decay is less when such quantities of fluoride are present in the water used for drinking than when there is none. All but three of the 34 samples analyzed contained from 0.1 to 1.0 part per million fluoride. Three samples contained 1.1 to 2.0 parts per million. Nitrate The significance of nitrate in drinking water has received considerable attention in recent years since the discovery that high concentrations of nitrate in water used in preparing baby formulas may cause cyanosis of infants ("blue babies").A concentration of 90 parts per million of nitrate as NO3 in drinking water is considered by the Kansas State Board of Health as being dangerous to infants, and some authorities recommend that water containing more than 45 parts per million should not be used for preparation of formulas. Cyanosis is not produced in adults or older children by these concentrations of nitrate. Nitrate found in well waters in Chase County may be derived from two sources: (1) nitrate minerals naturally occurring in the rocks from which a well derives water or (2) organic action. The second of these two possibilities is the more probable, inasmuch as no nitrate minerals are known in any of the rocks at or near the surface in Chase County. Bacterial decomposition of organic material, either plant or animal, in the topsoil produces nitrate. Especially during the early spring and late summer, when plants are relatively dormant, large concentrations of nitrate can be built up in the soil. Barnyards also are sources of organic material high in nitrate. Of the 32 water samples (excluding municipal supplies) from wells in Chase County that were analyzed, 19 percent of the drilled wells and 33 percent of the dug wells contained more than 90 parts per million of nitrate. The maximum amount determined was 518 parts per million, from a dug well (18-9-25cc), and the minimum determined was 0.88 part per million from a drilled well (22-6-26cc). Sanitary Considerations The analyses of water shown in Table 7 show only the amounts of dissolved mineral matter and do not indicate the sanitary quality of the water. However, an abnormal amount of certain mineral matter, such as nitrate, may indicate pollution of the water.Dug wells and shallow springs are more likely to become contaminated than properly constructed drilled wells, generally because they are not effectively protected from surface waters at the well or spring opening. Drilled wells are generally protected by the casing, although many are not properly sealed at the top. A well should not be located near possible sources of pollution such as barnyards, privies, and cesspools. |
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Kansas Geological Survey, Chase County Geohydrology Comments to webadmin@kgs.ku.edu Web version March 2001. Original publication date Aug. 1951. URL=http://www.kgs.ku.edu/General/Geology/Chase/pt3_chem.html | ||
