. Preventive medicine and hygiene. is of a specific case. Therefore several selected analyses andinterpretations have been given below. Allowable Limits.—The following are sometimes considered as theallowable limits of the impurities commonly regarded as permissible indrinking water. Chlorin depends upon the normal chlorin content of unpolluted sur-face waters in the neighborhood. Bacteria not over 100 per cubic centimeter. 868 IXTEEPRETATIOX OF SAXITARY WATER A:NALYSIS Colon bacillus ,-hoiil*] Ije absent from the ground water. Xot morethan 1 per 10 c. c. in a stream or in a river w^ater. Free
. Preventive medicine and hygiene. is of a specific case. Therefore several selected analyses andinterpretations have been given below. Allowable Limits.—The following are sometimes considered as theallowable limits of the impurities commonly regarded as permissible indrinking water. Chlorin depends upon the normal chlorin content of unpolluted sur-face waters in the neighborhood. Bacteria not over 100 per cubic centimeter. 868 IXTEEPRETATIOX OF SAXITARY WATER A:NALYSIS Colon bacillus ,-hoiil*] Ije absent from the ground water. Xot morethan 1 per 10 c. c. in a stream or in a river w^ater. Free ammonia 0. 03 Albuminoid ammonia 0. 07 -0. 35 Nitrogen as nitrites None, or at most a trace (0. 0004) Nitrogen as nitrates to [Parts per million] The standard adopted by the government ^ for drinking -^ater sup-plied by common carriers in interstate commerce demands that the totalnumber of bacteria shall not exceed 100 per cubic centimeter whengrown on standard agar plates and counted after twenty-four hours in-. f:>;;^^-r.:;J;Suj^^^^ Much Organic Matter CI» NO2 & NOz Feui or No Bacteria Organic Mattersmall amt. CINO,no NO. Few or No Bacteria Fig. 107.—Diagram Illustrating the Character of the Ground Water in Rela-tion TO Soil Pollution, to Assist the Interpretation of a Sanitary Analysis.(See also Xitrogen Cycle, page 773.) cubation at 37° C. Further, that not more than one out of five 10 c. of any sample examined shall show the presence of organismsof the bacillus coli group. These figures must not be taken literally, and are not given asstandards of purit}^ but the maximum limits of the impurities allowableunder ordinary conditions. It will be seen from the illustrative analysesgiven below that at times these limits may be exceeded without sanitarysignificance, whereas at other times a water well within the prescribedlimits may contain infection. For a better understanding a number of sanitary analyses of waterare given with an interpreta
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Keywords: ., bookauthorwh, bookcentury1900, bookdecade1910, booksubjecthygiene
