V‘I—‘W w- . v yyyy I“ 1‘“ l T' THE RELATIVE IHPIIIITAIICE 0T STREPTBCDCDI, E.”‘IEII'CIIIA CBLI, AIIII TOTAL CGIIIIT AS INIJICIITOIIS D. P I‘ IITIIIII III CHI-‘IIIIIIATEII SWIMMING 90018 TI‘ESIS TOR DEGREE III II. S. Ri-BEBT T. HABERMANN 1935 ' - "“"~M-i 1am; . a I h n | I - / (I .\ n . \ AK, . \ THE RELATIVE IMPORTANCE OE STREPTOCOCCI, ESCHERICHIA COLI, AND TOTAL COUNT AS INDICATORS OE POLLUTION IN CHLORINNTED SWIMMING POOLS Thesis for Degree of M. S. Robert T. Habermann 1935‘ MICHIGAN STAEE COLLEGE of AGRICULTURE AND APZ’LIED SCIENCE THE RELATIVE IMPORTANCE OF STREPTOCOCCI, ESCHERICHIA COLI, AND TOTAL COUNT AS INDICATORS OE POLLUTION IN CILORIIATED SWILMING POOLS A Thesis Submitted to the Graduate Eaculty For the Master of Science Degree Department of Bacteriology and Hygiene by y/ . . {V 5 Robert T. Habermann East Lansing, Mich. 1955 \ .‘rHrsvs CONTENTS: ACKN OI“! LLDGLEN T IL TRODU CT IOL HISTORICAL PREPARATION OF MEDIA EXPERILEIITAL I The growth of streptococci in the media II The incidence of Streptococci, and Escherichia coli in chlorinated swiming pools DISCUSSION CONCLUSION LI TERATURE CITED ‘Q‘i‘ia A ’NOJLLDGMLNT: The writer wishes to acknowledge his indebtedness and to eXpress his gratitude and thanks to the following; Dr. I. L. Hallmann, for his untiring guidance, advice and help, Er. C. S. Bryan for his abks assistance, and Dr. Ward Giltner for his helpful suggestions. The belief that the maintenance of a residual chlorine content of 0.2 to 0.5 p.p.m. in a swimming pool at all times is a guarantee that no bacteria are present and therefore, a guarantee that disease germs are also absent has been shattered by the bacteriological picture presented through the intro- duction of the sodium thiosulphate treated sample bottle for collecting the pool-side samples. The resulting bacterio- logical phzture is sometines quite startling when.contrasted T" I} to that obtained by the use 0 the usual sample bottle. With the old method of sampling, the residual chlorine continued in its gradual but ccnstant destruction of the bacteria present in the bottle during the period of trans- portation to the laboratory and during the storage period subsequent to examination. The results thus obtained generally showing sterility, were not representative of the pool water. The degree of purity depended to a large extent upon the rapidity of handling the sample. On the other hand, the scdium thiosulphate treated sample bottle gives the actual bacteriological picture of the pool at the time of collection, because the sodium thiosulphate elimina es the germicidal chlorine and frees the bacteria from any further injury from the chlorine. The sample may'then be transported to the laboratory and cultured the same as any unchlorinated water. That the resulting bacteriological picture using this method of samplin;, as recommended by Itallmann and Cam? (1), itftotally different from that obtained with the old sample bottle was vividly demonstrated in the studies of t're above- mentioned workers. They found in a small pool in Detroit, much higher total counts and much higher Escherichia coli and streptococci indices when the samples were tested immediately after collection. Although they showed that the presence of residual chlorine even in amounts of 0.2 to 0.5 p. p.m. of available chlorine was insufficient to effect cmtinued sterili- zation their data do not show the differences that might be expected under Varying conditions. During the past year this laboratory has been collecting data from seven pools to determine these Variations in order that new standards may be developed or the present standards changed to fit the new picture that has arisen. This thesis is largely concerned with the presentation of these data. Swimming pool water, although different from drinking water as far as the bacterial flora is concerned, has always been tested in the same manner for purity. The significant bacteria in drinking water are the disease-producing bacteria that come from sewage pollution. On the other hand, the bacteria found in swimming pools are not only frcm the intestinal tract, but also from the nose, throat, and other exposed parts of the body. If Esch. coli were more resistant to disinfection than other organ isms encountered in swimming pools the present test would be satisfactory, but as shown by Klan—g (2) this is not the case. It appears evident that any method for the bacter iologie-al examination of swi mming pools should be based on the most resistant and the most 3 numerous bacteria present. The method of bacteriological examination recommended by the American Public Health Association Comm ttee on Swimming Pools in 1926 (3) is essentially the same as that required for drinking water. This stardard recognizes only the incidence of M. 39}; and the total number of colonies developing cbn beef extract agar at 3750 in 24 hours. rfhe committee has assumed that the absence of 2%. Bali- indicates that disease-producing bacteria are also absent. The data on which these standards are based were obtained by using the old method of collection and not by using the sodium thiosulphate treated sample bottle. The use of streptococci as an indicator of pool pollution was first suggested by Mallmann (4) when he found that the incidence of streptococci paralleled the amount of pollution more closely than did the Esch. coli content. although con- siderable work has been done along this line, still no careful comparative studies of the relative incidence of these two indicators, namely Lsch. coli and streptococci, have been made to determine their importance. Such a study is presented in this thesis. Before making this study it was found necessary to try various media for growing strepto- cocci to be sure that the method finally used was giving the streptococci present an opportunity to grow. The results of this work are also preserted. Historical In the last few years there has been much discussion as to the reliability of the colon index when applied to swimm- ing pool pollution. The first work along this line was done by Liallmann (4) in 1928. He shoved that Esch. coli did not parallel the bathing pollution. In a pool, where the only means of purification was filtration, he found that the streptococci index paralleled the number of bathers in the pool. That the presence of streptococci in swimming pools is not unexpected is demonstrated by a review of the literature. Prescott and Winslow (5), are of the opinion that streptococci occur more commonly on the surfaces of human and animal bodies than anywhere else in nature. Gordon (6), showed that certain C\ stre ptoc cci are present in normal mouths. In a laboratory eXQeriment conducted during the fall, lgallmann recovered only 2 alpha streptococci from the mouths of 45 college students. In the winter, however, he found only 2 students that did not harbor streptococci. In addition to these organisms, other cocci (emanating) frcm the nose and other exposed parts of the body are present in swimming pools. All types of streptococci have been found in swimming pools. Alpha and gamma streptococci have been isolated by Klang (2). He found that alpha streptococci would grow after being subjected to a chlorine residual of 0.9 p.p.m. for 90 5 seconds. Recently, Horwood, Gould, and Swachman (7) found beta streptococci in swimming pools in Boston. The type of infection obtained from bathing in pools and rivers is of importance in deterndning the relationship between enteric and respiratory diseases. This relationship has been studied by many workers. Manheimer (8), cites examples of both of these types of infection as reported by the following; Reece reports 54 cases of enteric fever among soldiers who used a swimming pool which contained sewage polluted water; Jager reported intestinal proteus infection among snldiers who had bathed in the Danube river; Pfuhl attributes 49 cases of typhoid fever to bathing in the El e; and Shiga reports 413 cases of dysentery from bathing in a river. It will be noted that only cases of enteric diseases were reported from swimming in rivers or in pools where untreated waters were used, thus showing the importance of the Esch. anli test for detecting unsafe conditions from polluted water. The following diseases, usually caused by pyogenic cocci, are also cited by hanheimei: Tehr reports 20 cases of eye infection amidst patrons of a swimming pool; Schultz re- ports 18 cases of trachoma in persons using a pool; and Skutch reports an epideudc of gonorrheal vulvovaginitis which Spread to 236 girls using a pool in Posen. Fa?bes (9), cites H.No Ogden as a source for the following: W.L.Lewis reports influenza, colds, sare throats, and occasionally pneumonia restricted to users of the swimming pool at horthwestern 6 University; Bunker reports nos e and ear infection among members of a swimming team at Brown University, and Onersbach reparts an outbreak of conjunctivitis and catarrhalotitis among the members of a swimming club. Fcrbes has examined a case of meningitis contracted in a swimming pool. Hasty (10) finds that the pool organisms are dh?ectly the cause of piranasal sinus.infection. It is interesting to note, in the above references, that all cases of enteric diseases were caused from swimming in rivers or in pools where untreated waters were used. Also that infection of the eye, ear, nose, and throat, generally caused by pyogenic cocci, were obtained only in swimming pools where water free from intestinal pollution was used. The evidence cited seems to warrant the cnnclusion that cocci are the important organisms to be looked for when testing swimming pool waters. In 1927 Mailmann (11) suggested that the ortho-tolidine test should supplant the gggl. ggli test, because Eggh. 323 were apparently absent from pools containing 0.2 to 0.5 p.p.m. available chlorine. Stovall, Nichols, and Vincent (12) in the same year made a similarreport. In a Later publication Hallmann and Cary (l) in 1952, contrary to the findings of. Schoeple (13), found that pool-side testing of swimming pools yielded large numbers of FSdl. coli and streptococci; whereas the same sample when carried to the laboratory and tested several hours later was found to be free from pollution. These data demonstrate that any standard based on the usial methods of examination wherein dilorinated waters were trans- ported from their source to the laboratory and where a marked time period intervened before testing, were incorrect. They found that, in either chlorine or chloramine treated pools, chlorine residuals used were not always sufficient to destroy all Esch. coli and streptococci present. The results show the inadequacy of the ortho-tolidine test and the necessity of a bacteriological analysis. They recommended the use of sodium thiosulphate t3 deohlorinate the sample at the time of collection to eliminate the difficulties of pool-side testing. Many methods and media for the isolation of streptococci have been reported, but their application to swimming pool isolations presents many problems. Houston (14) although searching for streptococci in polluted river water summarizes some of the difficulties as follows; "In searching for streptococci many difficulties are met with. Frequently these is no growth.in the broth tube, the streptococci having presumably lost their vitality. Sometimes the growth is greatly delayed, and on resorting to further sub-culture a negative growth is obtained, the organisns having been obtained in a state of feeble vitality. Again it not uncommonly happens that a growth occurs, but the organisms turn out an examination not to be streptococci." other obstacles met with.in isolating streptococci are the over- growth of other organisms and the inabili y of the strepto- 8 cocci to grow when seeded into other media from the ori;inal broth. (1 No study of media has been made to determine the best medium for growing streptococci from the swimming pool water samples. In order to know when a pool is free from strepto- cocci a medium.that will allow all the viable streptococci presezt to grow is necessary. The English.workers suggest the use of litmus lactose agar and dextrose neutral red broth for growing streptococci from polluted waters. hallmann (4) found that streptococci would grow in standard hictose broth when.swimming pool water was added. He demonstrated the presence of streptococci by making a microscopic examination.oi?tfle sediment in the bottom of the lactose broth tubes. Later LLallmann and Gelpi (15) devised a method to concentrate the streptocozci by drawing off the supernatant lactose broth with.negative pressure. In as much as only two liquid media have been used, namely, standard hictose broth and dextrose neutral red broth, a comparative study of th; various media was made. To determine the influence of the protein base, a comparison of beef extract and veal infusion was made. The latter infusion has been very satisfactory for growing many pathogens partimhrly streptococci. To determine the influence of the carbohydrate, dextrose and lactose were used. To detennine the influence of soluble proteins, the 9 following peptones were tested; Bacto-peptone, Eroteose- peptone and Neo-peptone of the Digestive Jerments Company, and a peptone manufactured by Fredrick Stearns and Company. It is well known that reptones vary markedly in their ability to grow various organisms. Gentian violet, havin 00 been used with success by Bryan (16), in isobating strepto- cocci from cases of mastitis by inhibiting the growth of a I. ‘ .J U) ch. coli and other contaminants in milk, was tested in the media using dilutions ranging from 1 to 50,000'b 1 to 1,000,000. Preparation of Ledia; Gentian violet liver infusion agar. The medium was prepared according to the directions of Bryan (17). The following formula was used; 500 cc. beef liver infusion 500 cc. tap water 20 grams agar 5 grams NaCl The medium was adjusted to pH 7.4 and filtered through non-absorbent cotton to clarify. The medium was sterilized by steam under pressure. Prior to use, defibrinated bovine blood was added to the melted agar (45°C) to detain a 5 per cent concentration, and sufficient gentian violet (l per cent aq. solution) to give a final dilution of l to 200,000 in the'medium. 10 Veal infusion Proteose-peptone dextrose broth. This medium was prepared according to the following formula; 1000 cc. veal infusion (The veal infusion was prepared by adding 500 cc. of'tap water to each pound of ground lean veal, mixing and then steaming in the Arnold steamer for 1 hour. The infusion was then clarified by filtering through a cheese-cloth). 20 grams of Broteose Peptone was added to the infusion. The pi was then adjusted to 7.4. This was heated in the autoclave at 15 lbs., pressure for 50 minutes to "break down the precipitate," and then filtered through a filter paper. To the peptone veal infusion 10 grams of dextrose was added. The broth was then tubed and sterilized at 15 lbs. pressure for 50 minutes.) Veal infusion Stearns-peptone dextrose broth. This medium was prepared the Same as the veal infusion Proteose- peptone dextrose broth, except that Stearns-qutone was dded. m Veal ininsion Neo-peptone dextrose broth. This was prepared in a similar manner, except that Neo—peptone was added in the place of Stearns-peptone. Veal infusion Bacto-peptone dextrose broth. This was prepared the same as the above, but Bacto-peptone was added instead of Neo-peptone. Lactose broth. Lactose broth was prepared according to the following formula which represents a doublt strength medium; 1000 cc. tap water 6 grams Liebigs meat extract 20 grams Bacto-peptone 10 grams N801 The broth was adjusted to a pH of 7. and filtered through non-absorbent cotton to clarifv. Twent grams of lactose was d L. 11 then added. The broth was tubed and sterilized at 15 lbs. pressure for 30 minutes. Proteose-peptone lactose broth. This was prepared in a similar manner, except that Proteose-peptone was added in the place of Bacto-peptone. Rec—peptone lactose broth. This was prepared the same as lactose broth, but Neo-peptone was added instead of Baoto- peptone. Dextrose broth. This was prepared by adding 10 grams of w dextrose to Bacto-peptone beef extract broth before tubing. Elood dextrose broth. Blood dextrose broth was prepared the same as the dextrose broth except that sterile defibrinated bovine blood was added to make a final concentration of 5 per cent. ‘ 0 Serum dextrose broth. This was prepared by adding 0.5 per cent serum to dextrose beef extract broth. Litmus lactose agar. Difco litmus lacUDse agar was used for the preparation of lfimus lactose agar. Blood agar. This was prepared according to the following formula; 1000 cc. tap water 3 grams meat extract 20 grams agar 10 grams Bacto-pepmone 5 grams NaCl The medium.was adjusted to a pH of 7 and filtered through non-absorbent cotton to clarify. The medium was sterilized for 30 minutes at 15 lbs. pressure. Prior to use, sterile 12 defibrinated bovine blood was added to make a final concen- tration of 5 per cent. Exwp er imen tal The expernnental work that follows is divided into two parts; the study of the growth of streptococci in different media and the incidence of streptococci and Esch. coli in chlorinated swimming pool waters. All of the various methods attempted in the growing and isolating of streptococci are presented. Both direct and indirect methods of isolation were attempted. The procedures were as follows; Direct methais. To assure the presence of streptococci, water was obtained from the Lake Lansing bathing beach. This water was used because streptococci are always present, even in diluted samples, when fifty or more people are bath- ing. The water was collected at the end of the bathing dock in sterile 500 cc. flasks approximately 400 feet from shore. The water was transferred to sterile centrifuge tubes under aseptic conditions and centrifuged for 40 minutes. The supernatant fluid was decanted and the sediment was streaked on three media, namely, blood agar, blood agar plus gentian violet (l to 10,000), and the litmus lactose agar. The results obtained when streak plates were made from the sediment of centrifuged water are omitted as all three media failed to grow the streptncocci. The use of blood agar, sextian violet blood agar and litmus lactose agar as media for isolating streptoca3ci was, therefore, eliminated. 15 The use of a.direct selective enrichment medium was tried. This medium was an adaptation of that used by Bryan (17). Bryan has successfully used gentian violet in liver infusion agar as a selective agent for the isolation of streptococci from milk from cows affected with mastitis. It was hoped that the gentian violet in the liguid media would inhibit the growth of most of the other bacteria found in the lake water and allow the unrestricted growth of tta streptococci. Dye dilutions ranging from 1 to 5,000 to 1,000,000 were tried. Sater Known to contain streptococci was tested in amounts of 10, l, 0.1, and 0.01 cc. The water was added in the case of the 10 cc. amount to 15 cc. of double strength lactose broth and in the smaller amounts of water to single strength broth. All tubes were incubated at 57°C for 72 hours when they were examined microscOpically. The results using gertian violet broth were unsatisfactory. Other organisms were always present and tea streptococci were found just as plentiful in broth tubes the had not received any gentian violet. EXperiments employing gentian violet in as an inhibitory agent direct isolations were therefore disanntinued. Indirect methods. Gentian violet liver infusion blood tar was made as diiected by Bryan (17). The liver infusion {D ()Q .-,r (T) [N 1 , 150 to 200 00., was placed in 500 cc. flasks and sterilized. To theznelted agar, cooled to approximately 45°C was added sufficient gentian violet in one per cent dilution to mane a final dilution of l to 200,000 and sterile bovine blood to make a 5 per cent concentration. 14 The technic used for plating the streptococci consisted in adding 0.1 cc. of the sediment from 24 hour lactose broth tubes to a number of petri dishes andzidding approximately 10 cc. of gentian violet liver infusion blood agar. The petri dishes were then gently rotated to distribute the organisms. The plates were incubated for 24 ho*rs at 37°C. The appearance of all three types of streptococci On this medium is the same as on blood agar. All streptococcus colonies were confirmed by microscopic exaaunation and by growing in veal broth in pure culture. Although the microscopic examination of the broth tubes often showed Streptococci to be present in the initial broth tubes, when the gentian violet fiver agar plates were negative, still alpha and beta streptococci were isolated in many instances. In the addition of gentian violet to the blood agar, the quantity used was found to be very important. If an insufficient amount was added, the streptococci were over-grown by other organisms and if too much was added, the streptococci were inhibited. The results obtained although not perfect are encouraging. This medium makes it possible to obtain in pure culture the various streptococci present. The medium was not used in the later routine studies. In studies by hallmann (4) streptococci were cultured from standard lactose broth used for culturirg l_-1_s_c_r_1_. _qg__l_i_. The effectiveness of this medium in the isolation of streptococci was never checked. Accordingly other media were tested in a comparative manner to determine the effective- 15 ness of this medium and also to discover, if necessary, a better medium. Several peptones and several types of infusions were tried. The media used are described in detail in an earlier section of this thesis. The procedure for Checking the media follows; A sample of water from the Lake Lansing bathing beach, during a periai of a heavy bathing load was transferred in quantities of 100, 10, l, 0.1, and 0.01 cc. to the different broth media using various concentrations of the broth medLa so the ratio of'water to the food nutrients was practically the same in all instances. The tubes were incubated at 57°C for 72 hours. At the end of 24 and 48 hours incubation, the per- centage of gas an evidence of Esch. coli, was recorded. “9 After 72 hours incubation, the supernata.t fluid was removed by suction and the sediment smeared on slides. The slides were stained with aqueous methyl-violet or gram stain and examined microscopically for streptococci. The microscopical reanlts obtained after 72 hours incubation at 57°C are tabulated in Table I. The growth of streptococci occurred in all media, but was more abundant in Bacto-peptone dextrose veal infusion broth, Proteose- peptone dextrose veal infusion broth, and Neo—peptone dextrose veal infusion broth. .Maiy additional tests were made on the various media listed with results very similar tm>tkwse presented in Table 1. Considering all of the data gathered, Eroteose-peptone veal infusion broth was found the best for growing streptococci from lake waters. 15a Table I. The results of a microscopic examination presenting the growth of streptococci in various media after 72 hours incubation at 57°C Medium Beef Extract hedia Bacto peptone lactose broth Proteose peptone lactose broth Neo-peptone lactose broth Bacto peptone dextrose broth Serum Difco-peptone dextrose broth Blood Difco-peptone dextrose broth Veal infusion media Bacto-peptone dextrose broth Proteose-peptone dextrose broth Neo—peptone dextrose broth =|l Amounts of water planted 10 +* ++ 4. ++++ ++ +++ +++ ++++ +++ l 0.1 - - 4. - ++++ ++ ++ ++ + + + + + ++ + + +++ + 0.01 ++++ ++++ +++ + to ++++ indicate degrees of macroscopic growth of streptococci in tubes 16 In a further study of nutrient media to determine their relative values for growing streptococci, it was decided to test their values on a chlorinated water frat a swimming pool. Accordingly the above-mentioned medium, Proteose-peptone veal infusion broth was compared with standard Bacto-pqptone beef extract broth made according to the directions of the Standard Methods for Water Analysis, 1955. An examination of Graph I will show that very little difference occurred between these two media. Because of the similarity of the results obtained, it was decided to use these two media in parallel over a larger number of’samples. The results of these studies are presented later in this thesis. Having determined the best media for growing streptococci, a survey of seven chlorinated pools was undertaken to determine which.medium.was best suited for the isolation of strepto- cocci under routine conditions. Eurther, more data are needed to determine the significance of streptococci, colon bad.lli, and total 37°C count in chlorinated pools when sodimn thiosulphate sample bottles are used. The work of Liallmann and Gary (1) demonstrated that pools that have been showing consistently negative colon indices and zero counts under the old method of sampling, showed at times marked evidences of pollution when sodium thiosulphate sample bottles were used for collecting the samples. Although these writers call attention to this M.0F IO CC. T0355 P05/77VE 09930th flme. Knuth 9n. Enid Ibfibflczm. hhn awn. mafia. LED b8 H»: a M I bmubazm Vmuah 9003* WQh ms. HSQEQ hflbmbudndnnx. I II I §WM9WNI .ONBNgM V935 mag 92.4.0 Ibmfiflozm hhfiflam. 900V}. I ‘ 20W 30% 3 fi 3?». was.“ a homo Iv u. 3.193 snubb- N§sm 9... hakbh 3‘0. 90be N l7 condition and suggest the use of the dechlorinated sample, they were unable, with the small amount of data they presented, to arrive at any figures pertaining to standards. further- more, it has been customary to collect samples at any time of the day, regardless of whether the pool was in use or not, ratherthan at peak periais of bathing load when the dangers of pollution would be greatest. For this study samples were always taken.during such periods. In this study the method of preparing the Sample bottle was changed. Formerly I.‘.allmann prepared the Sample bottles by adding approximately 0.01 gm. of powdered sodium thio- sulphate to the wet sanmde bottle. The glass stopper was therireplaced, a paper cover was placed over the stopper and the bottle was sterilized by moist heat under pressure. Unless the steam was introduced into the autoclav slowly, the sudden heating ireduently broke the'bottles. To avoid this, hallmann adopted the use of dry heat. In this proce- dure, the powdered sodium.thiosulphate is added to the dry bottle. The bottles are the; sterilized at a temperature not to exceed 200°C. If the temperature should exceed 220°C the sodium thiosulphate will deccmpose. Using this method, the bottles seldom break and sterile bottles are assured. In collecting samples, using sodium thiosulphate treated bottles, care was always exercised not to rinse the bottles, as the sodium thiosulphate would be washed out. To be sure that 18 this had not occurred, all samples after collecting for the bacteriological tests were tested with.ortho-tolidine to be sure that free chlorine was not present. In several instances where samples were collected by inexperienced inspectors, free chlorine was found in the bottle. In all such cases the data were discarded. All samples were tested by planting five 10 cc. portions into lactose troth (A.P.H.A.) and lactose protecse-peptone veal infusion broth respectively. Two 1 cc. portions were plated on standard plain nutrient agar. All cultures were incubated at 57°C for 4d houra Gas production was recorded at the end of 24 and 4e hours incubation. All tubes showing gas (plus or minus 10 per cent) were checked by smearing on eosin-methylene blue agar plates. The latter step was found essential in all cases because frequently gas prcduction vas not due to Isch. @311. All plate counts were made at the end of the 24 hour incubation. After the 48 hour incubation at 57°C, the fermentation tubes were placed at r, room temperature for c to 5 days. This was done in order that the streptococci that might be present would settle to the bottmn of the tubes. The supernatant fluid was thGl carefully removed by suction avoiding, as mrch as possible, the disturbing of the pre- cipitate in the bottom of the tubes. The sediment was then mneared on slides, stained, and examined microscopically for streptococci. 19 As each sample was collected, an ortho-tolidine test was made to determine the residual chlorine content of the pool. The number of bathers in.the water at the tune of collection and the tcflal time that had elapsed since the jroup entered the rater was recorded. These data were recorded on the report sheet Which accompanied the sample to the laboratory. This report sheet is presented on the following page. It will be noticed that this sheet provides a place for recording the laboratory findings. To determine the relative values of standard lactose broth and proteose peptone dextrose veal infusion broth in growing streptococci from routinely tested swimming pool samples, all samples received at the laboratory for a period of several months were examined using these two media in parallel plantings. The results are presented in Table II. The data show that with 268 samples tested, the following results were obtained; For the presence of streptococci 110 samples were positive with standard lactose broth and 113 with proteose-peptone veal broth. Considering the individual 10 cc. portions, the standard lactose broth showed 258 partions pom.tive; whereas the proteose peptone veal broth showed 292. These data indicate only a slight advantage for the Latter medium, an advantage that is likely within the experimental error in making the tests. nor the determination of gggh. gall, the standard lactose broth gave 28 positive samples; whereas the proteose- 20 Michigan State College Department of Bacteriology and Hygieie Name of Pool Date Time of sampling Residual chlorine at time of sampling Number oifbathers in pool Length of time in pool Sex oi’ bathers Bacteriological count on plain agar at 57°C 1 cc. 1 cc. 0.5 co. co. co. 24 hrs. 57 hrs. Percentage of gas produced in lactose broth 10 lo 10 10 10 1 0.1 0.1 0.001 24 hrs. 48 hrs. Confirmation of Esch. coli on eosin-methylene blue agar Presence of streptococci Esch. coli Aerobacter aerogenas Streptococcus index Colon index Remarks 21 peptone veal broth gave only 26, or a variation of 17.2 per cent occurred in favor of the standard hactose broth. Consider- ing the individual 10 cc. portions, in the standard lactose broth 67 portions were positive as compared with 51 positive portions in proteose peptone veal broth, or a variation of 23.9 per cent in favor of the standard lactose broth. For the determination of Esch. coli the standard lactose broth was unquestionably the better medium. In as much as the value of standard lactose broth was nearly equal to the proteose-peptone broth in determination for streptococci and far superior for the detection of Eggh.'goli, the latter broth was discarded. It appears that standard lactose broth is the best medium of those tested for the detection of both streptococci and tech. coli. The writer recommends that tins medium.be used for both tests. The selection of a simple procedure for.measuring the ollution of a swimming pool is of considerable conzern. At present, the presence of heel. coli together with a maximum.count of 200 is in general use. Harwood, Gould, and Swachman (8) report that "the total count at 37°C after 24 hours of incubation represents the best and most sinple index of the sanitary quality of water in the pool." It must be reranbered, however, that their work was done using the ordinary sterile bottles for collecting samples. The residual chlorine present undoubtedly played an important part in disturbing the picture of the actual 22 mam . mad _ mmm . OHH . Hm . om . be . mm . mom . Hapoe . at iL . a . . . . Ho . dm . mm . om . O . O . O . O . Nd . h _ a L. . a . .L . . 0H . w . ma . m . O . O . N . H . b . 4 . . 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L Hmpom L confiewmm mHoom L h Hmwnmw cw mpmdoo Hmwnwuown mHoom hp cmmqwnnm mummp Hagen cam Lan .nomm .LoOOOOLQmmpm Lo moqmcLonH I >H mewe 25 L 00» L L OLN L L 000 H 00Lm000 L0L09 L L L L L mm.m0 L L00 L 00.00 L 00L L Lo.00 L 000 a com 30L0p 0Lm000 .L00m L0.LL “I nmL “[00.LL H mm H1 00.0L u 00 w. 000 L0 0000m0 0L LL000 .L00m 00.0L “ 00 H 00.00 H 0 u 00.0L ut‘om H LL00 .L00L mgwgogm L0L0L L0.00 L N00 L 0L.00 L mLL u Ln.00 L 0Lm H L00000Lm0L00 mLLg0Lm LmLoa L¢.mm L 00» L 00.00 L mOL L mm.mm L 00m H L00000meLLm L0 LL00 .Lomm L0LLL0L L L L L r L L0.LL L 0L L 00.0 L 0 L L0.0L L 0L H L00000L00LL0 000 LL00 .L0mm spom L L #If Lr » [w Lm.m L 0L L 00.0 L m L L0.m L 0L L 0L0L0 LL00 .2000 L P r L L L { L0.0m L 000 L 00.00 L mLL L 0L.0m L NLL L 0L0L0 L00000L00LLm L L L L L Li L L L L L L ammo me b. Lopasz memo meLHmLmememo meLanpdomL womdamxw mmHmSmw LHw mo mpgsoo proL ngw LHoo Hmpoe L L ommLamxm mmHQBMm HH¢ .nowm .LOOOOOpmmLLm mo mozmcLomH a b mHnma ‘ ._. .L L .L .. LL A A L. L - L LL . o , _. L L. L L L. .. . L. . L .- L. _. L . I _ . L . »- _. L 26 pollution as it existed in the pools at the time of Gallecticn. In the light of the present studies, the conclusions of Harwood, Gould and Swachman appear unwarranted. To obtain some idea of the relationship of total counts at 37°C and colon and streptococci indices, the results of all the bacterial tests made on swizning pools has been compiled to show their relative value. In this compilation a sample is considered poSitive to Each. coli or streptococci if one or more of the 5-10 cc. samples planted in double strength standard lactose broth were found positive. The data are presented in Tables III, IV, and V. In Table III are presented the findings arranged according to the pools en 7 tested. These samples represent only routine samples tal only when bathers were in the pool. In all cases, the chlorine residual of the pool exceeded 0.2 p.p.m. and in a few instances over 1 p.p.m. of available chlorine. A ‘ very'marked variation in the occurrence of Escn. a311, streptococci, and total counts in excess of 200 bacteria per 00., existed in the various pools. Eastern High School pool showed only 1 sample containing Each. coli and 14 containing streptococci out of 55 samples tested. Eight samples had counts in excess of 200 bacteria per cc. This pool never had heavy loads; in general the loads were exceedingly low. On the other hand, Moore's Park pool, an outdoor pool, showed a high incidence of §§§Q° Elli (54)out of 121 samples). The bacterial counts exceeded 200 bacteria per cc. and the incidence of streptococci was also pre- 87 dominant. This pool throughout the season carried bathing loads far in excess of the capacity of the pool. Even with chlorine residuals of 0.6 to 0.8 p.pJn., pollution indices were invariably high. In Table IV are presented the data on samples gathered in serial testing. In serial testing, during a given bathing period samples were taken (1) before the bathers entered the pool, (2) during the bathing period every 21D 5 minutes, and (3) after the bathers had left, for a.p3riod varying from 5 to 15 minutes. In general, a series con- sisted of approxinataly 17 samples taken over a period of 20 to 45 minutes depending upon the length of the bathing period. In most cases these samples were purposely taken during periods of heavy bathing loads as the writer was interested in obtaining pollution curves for the entire bathing period. As a result the incidence of streptococci and Eggh. ggli would naturally ShOW’in a larger number of samples. In Table V is presented a summary of Tables III and IV. The percentage incidence of Eggh. 9311 alone and together with streptococni, of streptococci alone, and of sempfles showing bacterial counts in excess of 200 bacteria per cc. are given. A critical exandnation of these data fail to show aiy parallelism among the incidence of stregbcocci, been. coli, or excess counts. The data show that in the 704 samples tested 48.57 per cent showed streptococci, 13.55 per cent showed Lech. coli and 17.47 per cent had counts in excess of 203 bacteria per cc. In gereral it had been the writer's observation that streptococci were present when Esch. coli were present. 8 rep tococci freeuextly were present when Lech. coli was absent and when the counts were under 200 bacteria per cc. The arbitrary acceptance of a total count of 200 bacteria per cc. standard "ithout consideration of Lech. coli and streptococci would be unjustified and would not be in accordance with the data presented. It would seem more reasonable to conduct further studies on the signiiicance of _ sch.. 3211 and streptococci iron a sanitary standpoint and set the maximum numbers of these organisms that would not endanger the bather. The total count represents largely organisms of no sanitary value and should not be considered unless their numbers vary directly with the streptococci and Tech. coli; and this is apparently not true. The conclusion of He rwood, Gould, and Swachman, therefore, appears untenable. No objections were raised to the present swimming pool standards until 19 55 whenQMallmann and Gary (1) presented their studies on the bacterial picture of the swimming pool Pb during p Mrio ds 0 5 use. They found as stated briefly in the introduction to this thesis that, contrary to the accepted opinion, a chlorinated pool having the recommended chlorine residual (0.2 to 0.5 p.p.m.) when in use contained quite frequently large numbers of bacteria. This condition had escaped notice due to the fact that it was an accepted practice to collect the samples in the usual sterile sample bottle, tranSport them to the laboratory when convenient, and test them when convenient. This meant that under the most favorable conditions of collecting and testing at least ten.minutes elapsed before testing and, more frequently, one to two hours. During this period the residual chlorine continued to act and all the bacteria that might have been in the sample at the time of collection had been destroyed. The result was a sterile sample. With a chlorine residual of 0.5 parts or more, the report would always show sterile conditions irrespective of the size of the load at the time of sampling. To offset this killing action in the sample during transit, hallmann and Cary suggested the use of the sodium thiosulphate sample bottles. In the following presentation of the current standards for pools, it will be borne in mind that these standards were based on tests obtained on pools using the old method of examination. The bacteriological standards recommended by the Joint Committee on Bathing Places of the American Public Healdi Association and.the Conference of State Sanitary Engineers in 1926 (2) follows; "B. Bacteria Count on Agar or Litmus Lactose Agar -24 hours - 37°C.: Not more than 10 per cent of smnples cover- ing any considerable period shall contain more than 100 bacteria per cc. No single sample contains more than 200 bacteria per cc. "C. E. coli - Presumptive Test; Kot more than two out 30 of five samples collected on the same day, not more than three out of any ten consecutive sampdes collected on differ- ent dates shall show a positive presumptive test." The stardard for chlorine residuals (S) is as follows: "Whenever chlorine, calcium hypochlorite or other chlorine CQMpounds are used for swimming pool disinfection, the amount of available or excess chlorine in the water at all times when the pool is in use shall not be less than 0.2 p.p.m. or more than 0.6 p.p.m." 1 o On t.e tes1s oi these standards let us examine some . piols observed during the past ;ear. In Lansing there are three Junior High School pools of exactly the same diaensions with exactly the same equip- mént and carrying comparable bathing loads. These pools have a capacity of 65,000 gallons and a filter capacity for a six hour turnover of the water. The pools are 24 ft. wide and 60 ft. long. lnlets are located at the shalldw end and outlets at the deep end. Because the pools are exactly alike an the type and number of bathers are similar the bacteriological resu ts from.thsse pools have been massed together for the presentation of the data that follow; In Table VI are presented tha'bathing loads arranged according to the chlorine residuals of the pools at the time of sampling. It will be observed that the bathing loads~ are practically the same for all chlorine residuals, so that all samples collected were taken with approximately the same number oi bathers. In Table VII are presented the bacterio- 31 logical data arranged in the same manner as in Table VI. Interpreting these data on the basis of the standards of the Committee of the A.P.H.A., it will be noted that satisfactory results were obtained d0tm to a minimum chlorine residual of 0.4 p.p.m. With 0.3 p.p.m. chlorine, the pools were un- questionably unsafe as measured by either total count or colon indices. Although streptococci were in evidence at all chlorine residuals, a sharp increase in their numbers occurred at the same time the colon indices increased sharp- lyatCL3}Lme emprhm. The data presented show that these pools with a bathing load of 51 can be kept free of pollution, provided a chlorine residual of 0.4 p.p.m. or more is maintained. In Table VIII are presented the bathing loads for two pools, a 85,000 gallons. (a) and a 145,000 gallon pool (b). The loads are arranged according to the chlorine residuals as in the previous tables. In Pool A the load averaged 15 for all chlorine residuals and varied only from 10 to 16 bathers. In Pool B the average was 28 with extremes of 5 to 85. This means that in the latter pool the data represent very unsignificant up to extremely heavy loads. The averages on this pool mean very little but the maximums are important. In Table IX are presented the bacteriological findings for ?ools A and B. In Pool A with a load of 15 in 85,000 gallon of water, pollution should not occur even.with low chlorine residuals. It is surprising to find that 0.2 p.p.m. showed decided pollution as measured by our present standards. Table VI - Bathing Loads of three 65,000 gallon capacity pools arranged according to the residual chlorine contents of the pools at the time of sampling. Chlorine Bathing Loads No. of Residual Average hedian Linimum. Kaximum samples 1+ 51 28 15 40 8 0.9 57 56 28 41 12 0.8 as 55 18‘ 4o 13 0.7 52 55 19 42 15 0.6 52 50 18 40 50 0.5 50 50 15 42 57 0.4 28 26 16 47 25 0.5 26 26 21 4O 12 0.2 55 - 50 4O 2 mwwmss . m . o . o . m _ oo.m .oo.m . .ooma. u . 000.: N . m.o . . _ . _ . _ _ . . a . mmwmnb . o . o . b . m _ mmdm .om.m . _ o . mp . oomH. NH . n.o . _ . _ _ . . . . t . t 0mm . «m _ H . mm . m _ Nada .owdd _ . o . o . 00m . mm . v.0 _ . . . . r . _ _ . a _ r whenw . an _ a . mm . a . mods .om. _ _ o . mm . com , as . m.o _ . . . . . . _ . a r . mMmm, . mm . N . om . O . MH.H .mmdo _ _ o . b . ma . om . w.o . . . . . . _ . r b F L mmmm . ma . H . ma . o _ om.H .©¢.o . . o . oom. 0mm . mH . v.0 5 . _ . . . . . _ L r p t "0 mwmm . NH . O . muH . O . Om. . p O p a O — OH — ON . NH . w .0 . I» p . L — P F P L L L mmwm . NH . O . NH . O . Om.0 . O . — O — Om . OmN . NH . 0.0 u . . p — u . u p u f» - www.mwm — m p O u m - O _ wN mo — O — 0mm... - O p O . 0m . m - +H — u . — Ll — L b u b p F . wOOG . cam . @000 . 6mm . . . EBB . ESE . . 0mm . . maéooHo.wmmsm. psdoo so ommwm. . _:mea.naaau.:mawog_anm>m+, r; pudmmm . pops? mo HpHHMSU . chdH . MmoSH . Dorm pfidoo mfipmpomm .mmamasm.amsowmmm . ..pmmnpm . soaoa . . mo .oa.mmanoaao .H m Mo 93H mqagpwp omsnmpm as now mpsmuaoo Hmswflmmu.maanoamo map 0p mafionooow downsnnm mHoom hpaowawo noaasm ooo.mo wanna do spam amOHmoaoHnmpOsm wo.hawaasm I HH> magma Table VIII - Bathing Loads of a 65,000 gallon capacity pool (A) and a 145,000 capacity pool (B) arranged according to the residual chlorine content of the pools at the tine of sampling Pool Chlorine. Bathing Loads No.0f Residual Aver. Median Linimum. Laximum. samples A ‘ 1. 16 l6 16 16 1 0.5' 10 10 10 12 4 0.4 11 10 10 18 10 0.5 12 12 7 18 17 0.2 15 14 10 14 7 B 0.5 50 25 5 8o 50 0.4 27 22 8 85 44 ()1 As the loads are always small in this pool, the residual chlorine is kept between 0.5 to 0.5 p.p.m. at all times. In Pool 5 with much larger loads, a much higher chlorine residual must be maintained. In this pool, as in the three pools discussed earlier in this paper, 0.4 p.p.m. shows a safe condition, but with 0.5 or 0.2 p.p.m. the colon index and total count increased rapidly. Jith loads ranging up to 90, the chlorine residual is maintained between 0.4 to 0.7 p.p.m. with a median of 0.6 p.p.m. These data show what can be done on indoor pools under certain bathing loads using the total count and colon indices as mes urauents of pollution. Later in this paper a (I) presentation of streptococci will beznade. In Table X are presented data on a 240,000 gallon outdoor pool showing the extent of pollution in the presence of varying annunts of chlorine. An examination of this table reveals the fact that according to our present standards this pool was unsafe at all chlorine residuals up to l p.p.m. when based on either the colon index or the total count alone, or both. These results are in marked contrast to those obtained with the indoor pools, but when the heavy load, leek sf proper bathing prior to entering the pool, and the use of all types of unsterilized suits are consider- ed it can readily be understood that excessive pollution ‘ enters the pool. ide r ults show that it is more diffiCult (D (i) to sterilize the water under the canditions found in this outdoor pool, than with an indoor pool with similar bathing .0 way 0% m L©.H LNHLO OommL C) mm ) mmmm L mfi L m L L L L L LL L L L L L L L L L L L L rl mmwm L $& L O L ¢m L O LNLH L L OOQML O L NH L ww L m.0 L m L L L L {L L, L L L L L‘ LI L L L L L L L L L L L L r‘ L L L L L L L Li L L L 0%mwfiD L m L H L d L N LOoN LMNL L 0000. 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L N L we L H 6.0 L moo L 00m" L O L OmH L m L m.0 L L L L L L LL L L L L L L QOHPmmSHL L b L H L m L O LOom LOoH L 0&0 L O LOmN L m L 0.0 L L L L L L L L L f L L L medw L H L O L H L O 14L 0 .0 L O L 0 LC L H L +oH L Ofim L L L L L n L L L L Li L Qmmv mmsmwfi: L m L m L m L H LNLQ LONJV L OOOLOH m L OOOHL OH L 0.0 L L L L L L L L L L L L L mnfiwmfid L b L 0H L ON L m Lflm LOmoLV L OOOLHVN mH LOOONL 0N L boo L L L L L L L L L L L L L 3.3% L L L L L L L A Lea. .36 L 08.3 o .83. a L do L L L L L L L L L L L L L memfim: L N L H L N. L H LOJQ LONQH L COOLHL 0 L100,” L m L 0.0 L L L L L L L r} L L L L L L LLOHpmmdeo L N L H L m L O Loofi LOOLO L OmH L O L ban L m L +.H L dram L L L L L L L L L l L L LLLLOHHSLLLm. L coon. L dflfl L @005: L cnm L L SSE L SE L max min L L L L L Lnoaoo so an an assoc no women chsHLNoomH. sawed nflnmaanmdemmHmsdmLaseoflmmaL pmommm L nouns mo waamdd LummnumLsoaooLOo a assoc anmuommL mo .oaLmnflnoanuLwomsom M. L L L L L L IF Ill maflamdem Ho ounp men we mpsopgoo osflaoago Hmseflmws onp ou mu.gmooow homespun Hoog mqfifififiam moccpoo soaanm OQQLQ¢N n LLo sumo HmofluoaoLLopomp mo massfidm I H manna 8 (>1 loads. f the bathing loads had been.materially reduced, the number of bacteria wouki have decreased according y. Ereguently the number in the pool and on the runways exceeded 400 bethers, although the number in the pool seldom exceeded 100. During the last summer when a protracted cold Spell occurred and the bathing loads in this pool decreased to a decided degree, the pollution lessened. This would indicate that e reduced bathing load would result in a pool of good quality which would meet the present standards. The studies presented so far have dealt with the total count and colon indices and no attention has been.paid to the streptococci present. An examination of Tables VII, VIII, and IA shows that s reptococci were present in most of the samples examined and that they were quite evident in chlorine residuals wher both appreciable total counts and colon indices were absent. Particularly in the samples collected from the outdoor pool (Table X), the incidence of streptococci was extremely high. To determine their occurrence in pools, a study was male of 145,000 gallon pool durin: heavy bathing loads. A progressive semplin U“ 1 procedure wus used taking samples at intervals of two minutes throughout an entire bathing period. The results of this study are presented in Graphs II, III, IV, and V. To determine the rapidity of their occurrence in a pool, all of the swimmers (66 men) were lined up at the edge of the pool and ordered to enter shhultuneously. The results are presented in ‘raph II. It will be observed that the pool, which previous to thezmussed entrance of the bath~ E9 ers was sterile, within 20 seconds was showing a maximum index of 10. 2his:m3ximum index continued for 2 to 3 minutes when a dLninution of the streptococci occurred in spite of the fact that the bathers remained in the pool. Later in this period the bathers were out of the pool 5 minutes and when they returned to the water, immediately the strepto- cocci index went up and then as they remained in the water the numbers became less. When the bathers have been out for 10 minutes the pool was again sterile. Ho Lech. coli or total count was obtained at any time during this eXperiment. As shown in Graphs III and IV} similar experiments were conducted except that the bathers entered the water as soon as they entered the natatorium. This meant thst for a period of 14 minutes each bather had entered the pool for a few minutes and then retired to the runways for instruction for the period. The actual number in the pool at any one time under these 0 nditions seldom exceeded 20. when the entire group entered at once later in the period the streptococci were less pronounced then they were when they entered initially simultaneously. In Graph V, the loads were introduced into the pool in groups for 4 to 10 minute periods interspersed with rest periods of 5 to 10 minutes. The streptococci indices accordingly rise and fall with the shift in the bathing load. Incidently this graph shows another interesting observatiOn. In collecting these samples, theEictual number of bathers in the pool was counted at the time each sample was collected, H \ \ m LL. \\ w L P a \ LL LL 5 L E .L \ m \ a. \ m L \ \ \ \ of: .2 NW 9325055090: Wfibxka \\< L 30h QHSLQ Sombmuhmfixm. .mxtbhxzm DQLQEQ Chm. . .. 4.»pr sonooQ Sums 0 33. 885. desk ’al” I V I U L &\\\\ \“ "‘ / ‘ '\\\\\\\\\V \\\\}L‘Q{\\ PE \\\\\\\\\\\ 90be NM i2. L L. ELL goes on? 25.. n3. amnesia. amass: I o. LL Po. LL. m3 SSEQ 503% I. 0.0 3%? H0855 GQS§§h Lame. R. 6.2 taboo eke 9.. $53. urged. sass: $35. 3.8 83. 9.82% 882 so? W $3....be NH. OK Emu: VN 3M? «0 4; 6 Q 0 BA TH/AG l. 0.40 o L o l0 CC. TUBES SHOW/N6 POSITIVE mLLfiflw-LQOFOQOLLB 325360. §< LL. DQOF Qu$Rn FOLD I. V“ km? 3355 GOQEN- .I Q (a. “05.02 \2DMX .I Q G O 0 w. 0 _ ”6 X“ U 0 5 ts Q ‘ ‘ ‘ \‘L‘: L. o o \ \2 / WW gm\\\\\\\\\\\\\\\\\\\\\\i / LL / \ &\ / .t L‘\ \\. &m\ + / .LI .0 up .2. .8 «LL «L. .L Lei Nix». \\< :xéQflMh SHOW/N6 POSITIVE /0 CC TUBES EOHMLQOBQQQLF W$b§<0% \>\ LL 305 9320 9990?. H .Luhcmhmuufi V»: («X tbh§380 9:. m. 9.985. 353$». mobbed I o. .L mm: WLUL‘S‘Q FOLD IVN {Hz H0355 QQSL § O O G \ L L L, / o L as L LL LL L / w ’ \J 0 LL ’ V O LL36 w LL L LL L L . ‘ LI ’ 0“ w \/ \. bQ m L L L L L“ \ W \\ LLL r L \L \L \» , -. x t we- a 4 .w .LL. .3 ate 3:». x2 {LQQNNW 40 It was interesting to note that the number never exceeded 40 although the 72 present were free to enter if they cared to DJ 0 so. The part pl“yed by the various strains of streptococci in the respiratory diseases and their prevalence in the intestinal, buccal, and nasal discharges make the presence of streptococci in the pool very questionable. Frankly I would rather not see them in the pool, but to eaninate them would mean decidedly analler bathing loads and decided increased in the chlorine residuals, either or both of which decrease the usefulness of the pool. Judging from the data available, it would seem.advisable to continue the established standards, and require the use of sodium thiosulphate treated sample bottles. Before leaving the topic of standards of pollution, it might be of interest to examine the present standards for bathing loads as recommended by the committee on Bathing Elaced (5). The;maximum bathing loads for a recirculation pool with continuous disinfection are as follons; "The total number of bathers using a swimming pool during any period of time shall not exceed 20 persons for eadi 1,000 gallons of clean water added during that period." What would the maximum load be for a pool like that at Michigan state College? This pool has a capacity of 145,000 gallon with an 8 hour turn-over and each 24 hours fresh water to the amount of 50,000 gallon is added. mhe amount of clean water added dairly amounts to 5 times the total capacity i 41 (145,000 gal.) + 50,000 gallon of fresh'water or 465,000 gallon total clean water added. The committee allows a maximum of 20 bathers per 1,000 gallon clean water so the pool may have a load of 9,300 per day. As the pool Operates 10 hours daily this would mean 950 bathers per hour. Such standards have outlived their usefulness and should be revised. The ccmmittee also places limits on the lo d based on (L? f the safety factor. ”hey divide the pool into 5 zones, namely diving zone, swimming zone, and non-swimmer zone. Limits for egch zone are as follows; diving zone - 10 ft. area beyond diving board allow 3 divers allow;g_divers on runway total — 12 divers -wimmin5 zone allow 36 sq. ft. per swimmer " 5&3 of swimming load on runways or 27 sq. ft. for all swimmers non-swim ing zone alloy 18 sq. ft. per bather allow 1003 of non-swimmer load on runways or 10 sq. it. per non-swimmer Safety limits for pool at L.S.C. based on these standards diving area-30 ft. by 20 ft. = 2 diving boards allows 6 divers " 18 divers on runway - 24 divers swimming area - 50 ft. by 50 ft. = 1500 sq. ft. ‘- 1500 - 27 = 55 winners - 55 swimmers non-swhnming area - 600 sq. ft. 600 - 10 = 60 non-swimmers_§g__ total load 159 bathers Or if entire pool is used for swimmers 90 ft. x 50 ft. = 2700 sq. ft. 2700 s 27 = 100 bathers eeneral far in excess of C. These safety limits are in practical teaching loads and 1 :5 my opinion in excess of Safety loads. I have repeatedly watched in the college pool, the number oinathers in the water at any one thus when diving was not permitted and I have never counted more than 40 bathers at one time in a class of 80 or 90 men. This gives each.swimmer 07 sq. ft. of swimming area instead of 56 sq. ft. allowed by the committee and allows 50 per cent of the group on the runways which would permit a class of 60. The area per each member of the class would be 45 sq. ft. instead of the 27 sq. ft. allowed. With this load a swimming pool of the size mentioned can be easily maintained in a safe condition as measured by total counts and coli indices. It has been our experience that the smaller pools (65,000 gallon capacity with dimensions of 60 ft. x 25 ft.) can carry heavier loads than the larger pools, so that the area per SD bather may be lessened to a figure approachinr that of the presaat standard. I would suggest 30 sq. ft. per member oi the class 6?, a pool of these dimensions, a maximum of 45 bathers at any period. 43 Suggested recommendations for'ccmsideration of the committee on standards. 1. Abolish maximum limits base on clean water added 2. ;ase maximum lons on surfice area of the pool. 3. Adjust maximum loads on ability of the pool water to remain bacteriologically safe rather than on the safety limit. Arbitrarily the area per bather is as follows; Eor pools of 2700 so. ft. or more - 45 sq. ft. nor pools under 2700 ed. it. - 35 sq. ft. 4. Chlorine residuals should be based on bathing loads. Light loads may Operate successfully with low residuals and heavy lOads with highzresiduals, but in general with the bathing maximum recommended in this paper the chlorine residuals should range between 0.4 to 0.6 p.p.m., depending somewhat upon the type of water. 5. The present bacteriological standards as regards total count and coli index may be retained. 6. All smrples should be collected in son an thiosulphate treated sample bottles. 7. No recognition of the streptococci in the standard U) should be made until further studie on the significance of the streptococci have can completed. 8. Samples should be collected at the time of greatest pollution, nanely from five to to; minutes after the bathers have entered the pool. Samples for Sanitary analysis should never be taxen when the pool is not in use. 44 Conclusions Standard lactose broth is a satisfactory Ircdim.n for the growth of streptococci from swimming pools. I‘Io direct parallelism occurs among; the three ind ice-.tors of sv..":zi'-iin5 pool pollutions namely colon index, streptococcus index and total 57°C bacterial count. Streptoco cci occur more frequently in chlorinated -~ ‘ t swimming pools than does iscn. coli. The period of greatest pollution occurs shortly after the bathch enter the pool. Chlorine res iduals of swimming pools should be maintained betVJeen 004 to 0.6 p.p.m. fl. -;.- C ,1 O 10. ll. 45 Literature Cited Mallmann, V.L. and Cary,‘hn. Jr. Study of Eacteriological.flethois of Testing and means of Disinfecting Water with Chlorine Am. Jour. Pub. Health, 25:35, 1935 Kleng, Iervin The Significaice of'Streptococci in measuring the Sanitary Quality of a Swimming Pool Thesis for the Degree of.h. S., 1955 Report oi the A. P. H. A. Committee on Swimming Pools and other Bathing Places Am. Jour. Pub. dealth, 16:1136, 1926 Icallmainn, 1.1. L. Streptococci as an Indicator of Pool Pollution Am. Jour. Pub. dea1UJ, 18:771, 1928. Prescott, S. 0., and Winslow, C.E.A. Elements of Hater Bacteriology (5th Ld.), p.118 Gor'd on, Mo 30 Report on a Bacterial test for Estimating Pollution of Air Supplement to the Thir‘y-second Annual Report of the LCCel Goverrment Board Containing the Report of the Medical Officer, 1902-05. Harwood, M.P., Gould, 3.3., and Swachman, H. Indices of the Saxitary Quality of Swimming Pool Water Jour. Am. Water Works Assoc., 25:124, 1953 Kanheimer, W.A. studies on the Sanitation of Swimming Pools Jour. Infect. Dis., 15:159, 1911. Eorbes, J. B. The Dangers oi‘the Public Swimming Bath. Lancet, 2:728, 1921 HaStL’.’ IE. .14. Paranasal Sinus Infection and Swimming Jour. gm. Led. lsscn., 89:507, 1927 Lia l 11:15:; nn , . L . The Ortho-tolidine test for Free Chlorine as an Indicator of Safety in the Swimming Pool hm. Rep. hich. State Bd. of Agri., 1927, p. 1927 12. 12. 14. 16. .9 C) Stovall, H. D., Vincent, and richols Renovation in Swimming Pool Control Am. Jour. Pub. Health, 16;257, 1926 :cdoeple, 0.E. Time ?actor in Chlorine Sterilization of Swimming rool .at:r Tenth hm. Rep. Ohio Conference on jater Purirication, ‘, OZ \ 4.1;, avg) Houston, 4. C. Bacterioscopic Examination of Drinking Jater, with Particulur Reference to Rel;tions of Streptococci and Staphylococci with deter of this Class. Report or the Leuical Cifiicer of Local Covergment. London, Lngland. 1699-1900 hallmann, J. 3., and Gelpi, 3.3., Jr. Chlorine resistance of Colon Becilli and Streptococci in 3 Swimming Pool hich. Lug. pr. Sta. Bull. 27, 1950 Bryan, C. S. Examination of Lilk for Streptococci oflgastitis Am" Jour. Pub. Health, 22;749, 1932 ”"11117117111111?“flilflfuliilfllgijifllflm'ES