“WWI \anHl‘Ws l l I — ,_—_’__._—' _,——— —— 7—. — Hl‘WNH‘W‘, \ L } H014 low M CDCD\I BATHING BEACH POLLUTION INDiCES THESIS FOR THE DEG-BEE OF M S, Adolf Sypien 1934 BATHING BEACH POLLUTION INDICES Thesis for Degree of M. S. Adolf Sypien 1934 MICHIGAN STATE COLLEGE of AGRICULTURE AND APPLIED SCIENCE BATHING BEACH POLLUTION INDICES A Thesis Submitted to the Graduate Faculty For the master of Science Degree Department of Bacteriology and Hygiene by Adolf S pien East Lansing, Mich. 1934 TH Esra, C ONTENTS : ACKNOWLEDGMENT INTRODUCTION HISTORICAL EXPERIMENTAL TECHNIQUE TABLES DISCUSSION GRAPHS CONCLUSIONS LITERATURE ii} I? twine) Udr‘gflj ACKNOWLEDGMENT: This opportunity is taken for the expression of my sincere gratitude to W. L. Mallmann for his constant and effective guidance throughout this work. -1- BATHING BEACH POLLUTION INDICES IETRODUCTION Though the need of proper sanitary control of swimming pools has been recognized, and is being ac- complished. no satisfactory control methods for natural bathing places have been devised. There is no reason why the control of a natural bathing area is not as much to be desired as the one in an artificial place. Is it not illogical to insist upon rigid sanitary standards for swimming pools and none at all for bathing beaches? Cases are on record reporting disease transmission in natural bathing places, but in most instances the source of infection was suspected to be from the sewage which had been emptied into the water. As for the danger from the pollution caused by bathers there is no definite information. It is possible to control sewage pollution of outdoor bathing areas in many instances; however, this still leaves the problem of pollution by the bathers, which must be more thoroughly investigated before standards for control can be recommended. Up to the present time no detailed studies have been made of the pollution introduced by bathers into a natural bathing place. Most of the work done has been concerned with the extent of sewage pollution. Without minimizing the value of such studies, it seems evident that in bathing areas which receive no sewage. other information is needed before effective control methods can be devised. HISTORICAL Attempts. based on the total count and Escherichia 32;; content, have been made to classify natural beaches as to their sanitary conditions. In most cases this was done to determine whether or not sewage was contaminating the beach. California (I) placed a maximum of ten Eschegichia 32;; per cubic centimeter as indicating a safe bathing place. while the New York City Department of Health (1) allowed a maximum of 30 Egghnggli per c.c. In 1928 Winslow and Moxon (2) tested the beaches in the vicinity of New Haven. They found that the beaches known to be polluted had an Egghgwggli content of 14 to 19 per c.c. They suggested that an average of not over one colon bacillus per c.c. might be a reasonable figure, with a maximum of not over 10 per c.c. However, they believed that much more work had to be done before a definite stan- dard could be adopted. It will be noticed that Winslow and Moxon's investigations were carried out between the months of November, 1926 to April. 1927. Samples were not examined during the bathing season. Prescott and Winslow (3) have compiled enough data from various sources to show that bac- terial count in rivers undergoes seasonal fluctuation. There- fore, Winslow and Moxon‘s recommendation of a bathing beach standard based on winter samples does not carry any weight. -3- In a survey of Connecticut's shore bathing waters, Scott (4) found that the most used bathing waters were subjected to the effects of sewage pollution because of their proximity to the harbors Of large cities. He pre- pared the following classification of beaches: Class Average Esch. c211 Sanitary quality per 100 c.c. A 0-10 good A- 11-50 good B 51-500 doubtful C 501-1000 doubtful-poor D over 1000 very poor Scott (4) was the first to make some studies of the pollution introduced by bathers. In 1950 he selected two beaches relatively remote from outside polluting in- fluences for this study. He discovered that a slight in- crease in bacterial pollution occurred with dense bathing, and concluded that the pOllution from the bathers did not affect his classification of beaches very seriously. He realizes that conditions may be different in some of the country's large, thickly populated areas. Scott believes that the effect of pollution of shore waters by bathers is minimized due to the great diluting influences. The Michigan Stream Control Commission (5) in 1953 surveyed the waters of the Iichigan coastline and obtained results similar to those of Scott. Beaches that were loca- ted some distance from sewage outlets often had colon in- dices from 0 to 100 per 100 c.c. of water. The pollution caused by the bathers was not considered in this work. The beaches on the Michigan coastline, as a rule, are not -4- heavily congested. The bathers tend to spread over a relatively large area, so that with the diluting influ- ences in operation a study of bathing pollution might show different results from those in a limited inland lake beach. A method for the sanitary testing of a body of water suggests itself from Savage's work (6) on tidal mud. He believes mud samples are valuable in that they indicate pollution for the length of time that specific (typhoid bacilli) contamination is possible. This procedure should tried on bathing areas to determine whether it would have the same merit. The study of bacterial processes in sewage polluted streams is of interest in that it may shed some light on the factors responsible for self-purification of waters. That streams do not always give the same bacterial results from day to day is due to the fact that self-purification is in progress. Studies have been made to determine the phenomena responsible. In his work on sewage polluted streams, Jordan, in 1900 (7), came to the conclusion that the Chief reason for the bacterial self-purification was due to the "insuffi- ciency or unsuitability of the food supply”. Jordan was unable to satisfy himself that the plankton were of any significance. As for the action of sunlight, his evidence indicated that this was of no great importance. Whether the sun shone brightly or was completely obscured the same reduction in numbers of bacteria occurred. Samples taken be -5- at the surface:3%wn to a depth Of three feet revealed practically no change in the total count. The effect of plankton animals upon bacterial death rates was also looked into by Purdy (8) who found that the diminution of bacterial population was accomplished by plankton. Later Purdy (9) made the claim that water which is recovering from sewage pollution contains large numbers of plankton and related organisms. He is of the opinion that this is one of the factors in the self-purification of streams. The status of the streptococcus as an indicator of pollution is still in doubt. Search of the literature reveals many striking discrepancies. The streptococcus test has been used in England for many years, and is a part of their standard procedure in bacteriological water analysis. The medium used is neu- tral red broth recommended by Savage and Read (10); inci- dentally. this medium was first used for the detection of Each. cell, but its unreliability for this group was de- monstrated by Irons (11). In an early report of the purification of sewage Jordan (12) noted the comparative absence Of micrococci in sewage effluents. Winslow and Hunnewell (13) decided that he did not use a suitable medium. Houston (14) was the first to indicate that the search for streptococci was valuable in determining the sanitary quality of water. He isolated this organism, as well as the staphylococci, from impure water, sewage -6- effluents, crude sewage, and polluted soils. In a subse- quent report, Houston (15) stated that recent animal pollu- tion of a dangerous character seems to coincide with the presence of streptococci. Horrocks (16) considered this group of sufficient importance to warrant a chapter in his book on water bacteriology; however, he did not believe they represented recent contamination. Later, Savage and Wood (17) confirmed Houston's contention that the strep- tococcus group indicated recency of contamination. The results of the work on this group until 1902 were ignored outside of England when Winslow and Hunnewell (13) recommended that search for streptococci be made in any sanitary bacteriological water analysis. Prescott and Baker (18), also impressed by the importance of strep- tococci in this connection, suggested a medium for iso- lation. Rivas (19) was among the first to point out that the Eggh.lggli test as performed in 1907 was too limited. As for a streptococcus test he claimed that it could be Of no value. This he concluded for the irregularities in his work with effluent water; however, he made the suggestion that perhaps the technique employed was at fault. The following year Rivas (20) found the most numerous organisms in feces were the "sewage streptococci or other variety of cocci", while Eggh. ggli_was second. In sewage, the ”sewage streptococci or some variety of cocci" also predominated, while in this case Esch. coli was fourth. -7- He further states that since the purification of water is only partial and selective, the cocci persist regard- less of the relative purity of the water. Therefore, he considered that these "non-pathogens” could not be of importance as an index of pollution in water, but that the Bach. coli still remained the best. Houston (21), in 1931, using a procedure different from that of Rivas, examined seventeen sewage specimens and found Each. 22;; from a 100 to a 1000 times more numerous than the streptococci. Also, in observations of feces from different animals, approximately the same ratio of Each. col; predominance over streptococci occurred. More recently, the popularity of swimming pools has stimulated work of this nature. One of the pioneers in this field, Mallmann (22), disclosed that the strep- tococci content parallels the bathing load, while Eggh. 22;; is not a satisfactory measure of pollution because it is able to multiply in the pool. When chlori- nation is applied Eggh,‘ggli are killed before the strep- tococci (23). A test for streptococci devised by Mallmann and Gelpi (23) is now finding wider usage. The technique will be presented later in this thesis. At a conference of state sanitary engineers (24) it was proposed that all public bathing places, both na- tural and artificial, should be placed under the control of the local health authorities, and that these bathing areas should be of the same standard of bacterial quality as is required for swimming pools. -8- EXPERIMENTAL The beaches in lower Michigan are generally very small, averaging from 200 to 400 feet in length. Those located close to large towns are popular bathing places during the season. Since most of them do not receive any sewage pollution they are believed to be safe for swim- ming. Lake Lansing was chosen for this study because it is typical of the lakes in this region. Being located only seven miles from Lansing it receives large numbers of bathers. NO sewage enters the lake. It measures ap- proximately 1% miles in length by 1 mile in width. Only one beach exists on this lake and it is at the northern end. There is no inlet. An outlet is situated on the western shore. The bathing beach area is limited as shown in Figure 2. A muck line about 220 feet from the shore separates this area from the rest of the lake. Since this muck is disagreeable to wade in, the sandy bathing area itself measures about 350 feet in length, and 200 feet in width. The deepest point is five feet. Most of the bathers stay in the vicinity of the end of the dock which extends about 150 feet from shore. At first, samples were taken from the end of the dock (Fig 1, Point 1), near shore (Point 2 ), and middle of the dock (Point 3). Sand samples occasionally were obtained below those collected near shore (Point 2). -9— The middle of the dock sample was discontinued because it did not yield any additional significant information. The outlet (Point 6), about a half-mile from the beach, was adopted as a control point but early in the investigation it was abandoned in favor Of a more convenient sampling point which is about three-fourths of a mile south of the beach (Point 4), readily accessible, and relatively dis- tant from the polluting effects of bathers. Sometimes samples were taken from the middle of the lake (Point 5), and other points selected at random. As a general rule, samples were Collected early in the morning before bathing began, during light and heavy loads during the day, and late at night. This program was usually followed during the week-ends from Friday to Sunday, or from Saturday to Monday, depending on weather conditions. Samples were also gathered at random during the week. Most of this work was performed during the period from June 14 to July 31, 1933. To determine whether or not the same results would be obtained at another lake, it was decided to go through the same week-end routine at Park Lake which is in the same vicinity. A fee is charged for addmittance to the beach on this lake so that the bathing loads are con- siderably lighter than those at Lake Lansing. Figure l Amusement Park LAKE LANSING Haslet &am: *—-fl#MJ KEY: QB-Public Bathing Beach O-Sampling Points 1. End of Dock 2. Near shore, and sand sampling point 3. Middle of Dock 4. Control at Lakeside 5. Middle of Lake 60 OUtlet 3m. eds-mi {odemw mtEndmw Melons... exdq afloat Sow t hflu>L30 Egg-Eco {9931: .uekwfi. ¢ ”Cadum/ o < 54 0.5-me 9 .2 he m4 0 w u m, e ( new, .31 as; s-\ -12- TECHNIQUE Naturally, the methods employed in testing swimming pools and drinking water were applied in this study, and since the streptococcus index has been recommended for swimming pools, this was also investigated. The procedure was essentially the same as that re- commended by the American Public Health Association (25). Ten c.c. of water was pipetted into each of five tubes of double-strength lactose broth, and in single-strength lactose broth a l c.c., and dilutions of 1-10 and 1-100 were used. The calculation of the "Colon Index" was performed in praCtically the same manner as suggested by the Phelps method (25) in which it is assumed that the most probable number of organisms present in a sample is the reciprocal of the highest positive dilution. This gives the number per c.c. whereas in this work the figure was multiplied by 100 in order to state the result in terms of a 100 c.c. Thus, if the l c.c. and 1910 tubes were positive, while the 1-100 tube remained negative, the colon index according to Phelps would be 10, This means that the most probable num- ber of colon forms per c.c. was 10. In this study the in- dex would read 1000 meaning that the most probable number was a lOOOper 100 c.c. of sample. For further confirmation material was taken from the positive lactose broth tube which contained the least amount of sample, and smeared on eosin-methylene-blue agar, and an inoculation was also made into brilliant-green bile broth. -13- Counts were obtained from nutrient agar plates in- cubated at 37 degrees Centigrade for 24 hours, and at 22 degrees Centigrade for 48 hours. Proper dilutions were pre- pared to ensure accurate counting. The Mallmann and Gelpi (23) method for determining the streptococcus index was used. This was done by allow- ingthe lactose broth tubes used in the regular procedure, to stand another twenty-four hours, thus giving sufficient time for the streptococci to settle down to the bottom of the tubes. Then, most of the supernatant liquid was re- moved by suction. The sediment was smeared on slides, stained with methyl violet, and examined microscopically. An attempt to determine the numbers and varieties of plankton was made by the Sedgwick-Rafter method (2‘). At the completion of this investigation weather re- ports for the entire period were obtained from the weather bureau. These were plotted on the graphs showing the week- end data in order to ascertain whether or not there were any correlations. -14- Table 1 Lake Lansing May 6’ 1952, 3:00 Polio Station A: Distance Gas in lactose broth Count, from_§hore 10 10 10 10 197 l 0.1 A‘37 C. 25 feet - - - - - g;gg - 18 50 feet - - - - - + - 12 100 feet - - - - - - - 27 Station C: :2: Distance Gas in lactose broth Count, from shore _10 10 10 10 10 10 0,; 37 C, 25 feet + - - + - - - 8 __ 50 feet - - + i - - - :;g 190 feet + - i - - - - legLa Btgtign E: Distance Gas in lactose broth Count, ggrgm shgge 10 10 10 10 10 l 0.; 37 C1_#_ 25 feet - - + t, - ifi - .15 50 feet j;__t ta - + - - 22 100 feet + - - - - + - 17 Station A: May 23’ 1952’ 3:00 P.M. Distance Gas in lactose broth Count, from shore 10 10 10 10 10 1 0.1 37 C 25 feet + + + + + - - 67 4“_ 50 feet 1 + + j__g, - - 104 100 feet + + + - f - - 88 Station C: 1.1 Distance Gas in lactose broth Count, from shore 10 10 10 10 10 l 0,; 37 C, 25 feet + t. + + t - - 100 50 ieet 1 + + + w - - 9% Mt + + i + 4F - - 4 Station E: Distance Gas in lactose broth Count, from shore <10 10 10 10 10 l__0.l 37 C. 25 feet + i - + - - . 163 50 feet + a 4 + 4 - - 74 190 feet 1 + + + + - - 55 Table 2a -15- Week-end, Friday-Sunday Location: End of Dock, Lake Lansing Colon Strep. abunts No. Time Load Index Index 37 C. 22 C. Friday 7 1:40PM 62 1000 100 140 --- 8 5:00 77 10000 8 230 3000 9 9:00 95 1000 10 780 --- Saturday “PM 10 1:00AM" 0 10000 10 2000 --- 11 8:30 4 100 2 175 -~! 12 1:30PM 58 1000 10 500 --- 13 5:00 48 100 6 397 486 14 11:30 4 100 10 720 1290 Sunday An! 15 9:30AM 4 100 0 820 780 --=Count omitted. Table 2b Week-end, Friday-Sunday Location: Near Shore, Lake Lansing Colon Strep. Countsw—— No. Time Load Index Index 37 C. 22 C. Friday “— 7 1:40PM 62 1000 2 273 --- 8 5:00 77 10000 8 19000 --- 9 9:00 95 100 10 600 --- Saturday 10 1:60AM 0 100 2 500 --- 11 8:30 4 1000 0 328 --- 12 1:30PM 58 100 0 166 --- 13 5:00 48 100 4 452 485 14 11:30 4 1000 10 1300 1420 "' Sunday ‘— 15 9:30RM 4 10000 0 1810 2450 --=Count omitted Table 20 Week-end, Friday-Sunday Location: Control at Lakeside Colon Strep. Counts No. Time Load Index Index 37 C. 22 C. Friday 7 1:40PM 0 1000 0 _ 90 ~-- Saturday 11 8:30AM 0 100 0 150 --- Sunday 15 9:30AM 0 100 0 1660A _ 1240 Location: Near Shore, Sand Samples Friday 8 5:00PM 77 1000 0 8000 --- Saturday ~ 11 8:30AM 4 1000 5 3500 4250 Sunday 15 9:30AM 4 10000 8 1500 3040 --=Counts omitted -18.. Table 3a From Monday-Thursday Location: End of Dock —f Colon Strep. Counts No. Time Load Index Index 37 C. 22 C. Monday 1 10:30AM 0 1000 0 5000 7080 2 4:20PM 28 100 4 10000 14500 Tuesday :A‘ 3 9:30AM. 0 100 0 220 260 Tednesday 4 3:30PM 45 100 O 61 500 5 8:50 30 100 4 72400 76400 Thursday 6 7:30PM 31 1000 0 425 1300 Table 3b Location: Near Shore Monday 10:30AM 0 1000 0 117 1140 4:20PM 28 100 0, 180 690 Tuesday 9:30AM 0 10000 0 5960 8000 Wednesday 3:30PM 45 10000 0 1300 4000 8:50PM 30 1000 0 381 1870 Thursday 7:30PM 31 1000 0 780 2240 -19- Table 3c From Monday-Thursday Location: Control —' Colon Strep. Counts No. Time Load Index Index 37 C. 22 C. Monday L 1 10:30AM 0 1000 0 129 1100 Tuesday I 9:30AM’ 0 1000 O 5850 10000 Sand Samples: Monday 1 10:30AM 0 1000 O 3450 11000 Outlet: Monday 1 10:30AM 0 100 0 500~ 2500 -20- Table 4a Week-end, Friday-Sunday Location: End of Dock Colon Strep. Counts: No. Time Load Index Index 37 C. 22 C. Friday 1 1:45PM 70 100 10 300 800 2 5:00 54 1000 10 360 970 Saturday ' 3 12:30AM 0 1000 6 16000 --- 4 10:00 4 100 0 1580 2360 5 2:00PM 30 100 0 5000 8700 6 5:00 67 1000 4 820 1560 Sunday 7 10:00AM 0 10 0 300 380 8 3:45PM 200 100 100 127,000 156,000 9 5:00 250 100 6 600 1090 10 11:00 0 10000 4 420 1480 Monday 11 8:30PM 65 10000 4 - 242 1680 --=Count omitted Table 4b -21- Week-end, Friday-Sunday Location: Near Shore Colon Strep. Counts: No. Time Load Index Index 37 C. 22 C. Friday 1 1:45PM 70 100 8 500 850 2 5:00 54 10 8 100000 innum. —r Saturday 3 12:30AM 0 100 6 1600 --- 4 10:00 4 1000 0 270 1000 5 2:00PM. 30 100 0 1100 1050 6 5:00 67 10000 0 148000 71120 —P Sunday 7 10:00AM 0 100 0 211 340 8 3:45PM 200 1000 4 12000 9715 9 5:00 250 10000 8 1000 2000 10 11:00 0 100 10 240 1940 Monday 11 8:30PM 65 1000 0 500 3360 innum.==innumerable --aCount omitted Table 4c Week-end, Friday-Sunday Location: Control at Lakeside O‘Colon Strep. Counts: lo. -Time Load Index Index 37 C. 22 C. —P Friday 1 :45PM 0 1000 0 950 1540 Saturday 2 10:00AM 0 100 0 67 410 Sunday 7 10:00AM1 0 10 0 700 1500 10 11:00PM 0 10000 0 175 770 Sand Samples: Friday 2 5:00PM 54 100 5 9000 15600 Saturday 4 10:00AM 4 1000 0 2000 7500 —F* Sunday 7 10:00AM 0 100 0 22400 30000 10 11:00PM 0 10000 0 innum. innum. Middle of Lake: Sunday 7 10:00AM 0 8 0 139 360 innum.==innumerab1e Table 5a Week-end, Saturday-Tuesday Location: End of Dock Colon Strepl Counts: No. Time Load Index Index 37 C. 22 C. Saturday 1 2:00PM 60 1000 10 312 1170 2 5:00 _3 1000 2 490 1630 F7 Sunday ‘ 3 11:00AM 13 100 4 272 410 4 5:00PM 60 100 100 83 440 Monday 5 11:00AM’ 0 1000 0 44 224 Tuesday 6 3:00PM 56 10000 6 7800 --- --«=count omitted Table 5b Week-end, Saturday-Tuesday Location: Near Shore Colon Strep. Counts: No. Time Load Index Index 37 C. 22 C. Saturday 1 2:00PM 60 100 4 275 870 2 5:00PM 3 100 6 5100 7400 Sunday 3 11:00AM 13 1000 0 167 460 4 5:00PM 60 1000 4 480 610 Monday 5 11:00AM 0 1000 0 1500 7600 6 Tuesday 3:00PM 56 100 6 7040 --- Table 5c Week-end, Saturday-Tuesday ~25- Location: Control at Lakeside: 7 Colon Strep. Counts: No. Time Load Index Index 37 C. 22 C. Saturday 1 2:00PM 0 1000 1000 342 2220 Sunday 3 11:00AM 0 10000 0 210 400 4 5:00PM 0 1000 4 243 1340 Tuesday 6 3:00PM 0 1000 0 1203 --- Location: Middle of Lake: =: Sunday 3 11:00AM 0 100 0 96 300 Tuesday 6 3:00PM 0 10000 0 1500 --- Wednesday 7 9:15PM 0 10000 0 ll --- Location: Near Shore, Sand Samples: Saturday 1 2:00PM 60 10000 10000 850 3000 —’ Sunday 3 11:00AM 13 1000 2 480 4450 Monday 5 11:00AM 0 10000 0 3800 15100 Table 6a Week-end, Friday-Sunday -25- Location: End of Dock Colon Strep. Count, No. Time Load Index Index 37 C. Friday 1 2:00PM 55 100 4 393 Saturday 2 10:00AM 55 8 2 52 3 2:00PM 45 1000 100 345 4 5:30 102 10 1000 127 5 11:15 50 10 100 18600 Sunday 6 10:30AM 31 100 6 1230 Table 6b Week-end, Friday-Sunday Location: Near Shore Colon Strep. Count, No. Time Load Index Index 37 C. Friday 1 2:00PM 55 100 6 440 Saturday 2 10:00AM. 55 10 0 380 3 2:00PM 45 10 2 131 4 5:30 102 100 100 54000 5 11:15 50 10 100 850 Sunday 6 10:30AM' 31 10 0 950 Table 6c Week-end, Friday-Sunday Location: Control at Lakeside Colon Strep. Count, No. Time Index Index 37 C. Friday 1 2:00PM 100 0 1100 Saturday 2 10:00AM 100 0 140 3 2:00PM 100 0 3100 4 5:30PM’ 100 0 280 5 11:15 10 0 410 Sunday 6 10:30AM 100 0 200 Table 6d Week—end, Friday-Sunday Location: Middle of Lake Colon Strep. Count, No. Time Load Index Index 37 C. Friday 1 2:00PM 0 100 0 116 Saturday 3 2:00PM 0 6 0 30 4 5:30 0 100 0 122 5 11:15 O 10 0 75 Sunday 6 10:30AM 0 10 0 500 Table 6e Week-end, Friday-Sunday -30- Location: Park Lake Colon Strep. Count, No. Time Load Index Index 37 C. Friday ”- 1 2:00PM 30 100 6 435 Saturday h 2 10:00AM 0 10 0 166 3 2:30PM 26 10 6 234 5 11:30 10 100 10 560 Sunday 6 10:30AM 8 100 0 230 -51- DISCUSSION A bacteriological study of Lake Lansing was made by W.L.Ma11mann in May,1932 before the swimming season (Table 1). On May 6th samples taken at distances of 25, 50, and 100 feet from shore at stations A,C, and E (Fig. 2) showed counts well below 100 per c.c. and gas production was negligible (Table 1). There is no appreciable difference in count or gas production in samples obtained from the various sampling points. On May 23rd, after the bathing season was started, samples obtained from the same points revealed a definite increase in total count as well as in gas production. No examination for streptococci was made. These results indicate a safe bathing place under most of the standards recommended up to this time. In the present work the pollution introducted by the bathers is considered. The data are presented in tabulated form in the tables from 1 to 6 inclusive. The same results, with the excep- tion of those recorded in Table l, are plotted in Graphs 2 to 6 but more strikingly presented because the general trends are much easier to follow. The data in Table 2, "a" and "b” series are plotted on Graph 2, "a“ and "b” series, Table 3 on Graph 3, and so on through Table 6, ”a" and ”b". These are all based on week-end sampling, with the excep- tion of the data in Table 3 which represents samples from Monday to Thursday. Graphs 7 to 11 show the comparisons among the different sampling points. -32- The indices are plotted logarithmically, while the bathing loads, as indicated by the rod-like blocks, are plotted on a uniform scale. By studying one of the week-end graphs of samples taken from the end of the dock or from_near the shore it will be noted that results obtained in the afternoon and early evening samples usually showed an increase which often reached its height about midnight but seldom revealed a marked decrease. This is especially true of the strep- tococcus index. Next morning, when samples were obtained before bathers entered the water, the streptococcus index was zero, or if a few bathers were present, this index was comparatively low. The total counts and colon index did not go down to zero over night or at any other time during the period of study. Usually a decrease in these two indices was noted in the early morning samples though occasionally increases were noted. All indices are fairly representa- tive of pollution introduced by bathers, but if the total counts and colon indices for the entire period are compared with the control on Graphs 8 and 10 it will be Observed that there is not much difference. The control samples were not always taken every time a sample was collected at the beach, however, so that if this is considered in reading the graph the above statement will be found to be essen- tially correct. When the streptococcus is considered (Graph 11) -33- a striking fact is revealed-~there are no streptococci at a point free from bathers, while at the other two sampling points where bathers are present, the streptococcus index parallels the bathing load. At other points free from bathing pollution there are also no streptococci. Nevertheless, there are two exceptions to the above statement that streptococci do not occur at points free from bathing pollution (Table 50). When this happened a search was immediately made to find if any sewage was being dumped from the houses and restaurants bordering the lake at the control point. This was unsuccessful. Therefore, in order to determine the source of this or- ganism a number of samples were taken from the lake at points opposite suspected houses and a restaurant. From then on to the end of this investigation no more strepto- cocci were Obtained from any point in the vicinity of the control. Since sewage is not allowed to be emptied into this lake, and because the streptococci were found only on two occasions, it is natural to conclude that their occurrence at this particular time is of no significance. A sufficient number of samples was taken at different points outside the bathing area to strengthen the opinion that strepto- cocci in a lake of this type are found only in the immedi- ate vicinity of bathers. Because of this viewpoint the two exceptions are not shown in Graph 11. -34.. In the "c” series Of Graphs 2 to 6 the comparisons between the end Of the dock and shore are given. The colon index and total count comparisons for the whole five weeks are presented in Graphs 7 and 9 respectively. These reveal very little difference between the two sampling points, but in the "c" series of Graphs 2 to 6 it will be observed that the total counts and colon indices are some- what higher near the shore, while the streptococcus index is higher at the end of the dock, also shown on Graph 11. This further proves that the streptococcus index is a good indicator of bathing pollution because a more complete immersion of the body takes place at the end of the dock and, in this area, we have the greatest concentration of bathers. It seems that the streptococci disappeared over- night because they were not present in the morning before bathing began, and they did not settle down to the sand because the latter samples revealed no streptococci un- less some bathers were present. The streptococcus index seldom rises above 10, the colon index and total count rarely go below a 100. In a swimming pool the opposite is often found due to the fact that the more susceptible colon organisms are des- troyed by chlorination before the streptococci. Agar plate counts, incubated at 22 C. for 48 hours, were discontinued after the fourth week-end because they did not yield any additional information outside of the -55.. fact that they gave slightly higher counts. Often, sand samples were taken at the same point from which the shore samples were obtained. Total counts and colon indices gave slightly higher results than at any other sampling points. Occasionally streptococci were ob- served (Tables 2c, 4C, 5c) although in only one instance was the index high. As mentioned above, no streptococci were observed unless the bathing load was above zero. The Mallmann and Gelpi macroscopic examination for streptococci (23) was not applicable to these tests be- cause Of the high turbidity produced by the growth of the organisms. Due to the inability to investigate any additional factors concerned in this problem because of the large numbers of samples handled in the regular procedure, much study was not devoted to plankton and their influences. Enough, however, was accomplished to enable one to state that the total plankton population was high, the most com- mon forms present being the rotifers and water fleas. Two samples examined, one from the bathing area and the other from a point outside this area, manifested no dif- ference in numbers or species. Weather conditions such as prevailing winds, temper- ature, and amount of sunshine had no discernible effects on the results presented. A close inspection of the data reveals that a ”catch" sample would be Just as apt to give a false idea of the C ”6- condition of a beach as it would be to give a correct one. For example, in Table 4a, sample 8 the total count at 37 C. was 127,000, the load being 200; one hour and fifteen minutes later the load increased by 50 (sample 9) but the total count dropped to 600. In table 4b, sample 8, a load of 200 gave a count of 12,000, while in sample 6, with a load of 67 the count was 148,000. Such discrepancies have been observed at least once in each week-end table. Bacteriological exami- nations of a beach conducted in about the same time intervals as those presented here give a more satisfactory picture of the condition of a bathing place. During the last week-end the same routine was per- formed at Park Lake, which yielded the same general results as those depicted from Lake Lansing (Table 6e, Graph 6e). These results on streptococci confirm the conclu- sions of Savage and Wood (17) which were that: ”In parti- cular the finding of streptococci in any numbers can be accepted as indicating considerable and recent contamination. We consider that the streptococcus determination is very valuable on its positive side as an indication of recent contamination. As a means of judging the recency of the contamination it is even more valuable than the Eggh.'ggli enumeration.” These workers also compared the viability of strep- tococci and Esch. coli in sterile water and reported that the former organisms were practically eliminated at the end of two weeks but Esch. coli, multiplied over fifty-fold -37- of the original number at the end of eleven weeks. Mallmann (22) has presented evidence that Eggh, 23;; tends to multiply in the swimming pool, while streptococci do not. He obtained these data from a non-chlorinated pool of the recirculation type in which the water turnover occurs about every nine hours. Since some of the organisms were removed through the filters the increase in their numbers in the pool could only be accounted for by their multipli- cation. This was not true of the streptococci. These conditions are very similar to those in a limited bathing beach like the one at Lake Lansing. In case of streptococcus, it has been shown in the data that they disappeared over night, while Eggh, ggli_and total count sometimes remained stationary or even increased. That Eggh. ggli_remains viable and tends to multiply during the warmer months seems to be borne out when it is consi- dered that in the month of May the numbers were very low while in summer they were much higher. This was also true when practically no bathers were present for several days. It is evident from the data presented that in a li- mited bathing beach the conditions are similar to those in an untreated artificial pool. Therefore, there is no reason why the same bacterial standards employed in swim- ming pools should not be applied to a beach of this sort. Disinfection with chlorine has been tried in the Washington tidal basin (26) with good success as judged by the regular colon test. From a total count of over 175,000 bacteria -38- per c.c. in the entering water from the Potomac River . the reduction by the treatment lowers the count to less than 100 bacteria per c.c., Eggh.‘ggli is likewise re- duced, from 500 per c.c. to its occasional presence in two or three of the five 10 c.c. portions. The proposal of sanitary engineers (24) that all public bathing places be of the same standard of bacterial quality as is required for swimming pools, seems justified. In order to meet swimming pool standards it may be necessary to chlorinate the water by use of chloroboats, by having the area fenced off so that the bathing loads can be limited, or by a combination of such methods. .acn .zn esotpuI go °s201 723w“ ta on: aim, Eden.- rw on 2 S ta 41 z...» E. N Hwy D E l. @O// ea mMV/l r\ ,m/// \\ / \\\\\\\\ ea ,(\ cm 2 ., SEQ 2200 s m 0 R. L g :II. n ||||||||| .I.|\. .m s amassed Em. h t a B .2. .8 E a U m d m Ia rzw -40- {a a 9m... 7? a teen: zero _m+/ D I... / // .N. . / \\ V/II/ \ \\\ \ a / \ \ (\ em. 3 OVA; 3 ‘O‘I e ‘ I ‘I 0 III 0 p.53 30.». on ow 8 02 odorm Ow Iau / \ / / / ~45- as E .. $2 .llll l I lllll a. team l is- 533 e EL Jail Imus? \auwl XCNCH Luuuapm a ID/ i..... _ e \\ // \ // om \ ///.( \\ llllllpull ‘ 3))\\ as N a a \x. ./ coo .\ /./ \ m . NO \ ./ \ V. oxo . ./ . / Oxow. 1. /. .\ @/. s /. \ +- / . /. \. / .1 /. . / .1 /. .\ new to. $5 1 -47- GRAPH 4c End and Shore Comparisons Tbtal Counts l 3 \-1 Colon Indices v/ I 2. I , .4 __________ __ 0 Strep. Indiccs ~80 _.. 8 :3 N N to F (to 10 1:45,." #L Tit-13AM an ' L?” 757M .WL 757$ FM. 531;. Sun. -48- l 5.05 l I .l datum I use .Ii Bah cat 5 Show egg 9 9d 0% on rim. dam. ah. can an .335 ~49- js 9- o.» cm a.» / cm as K J. an£w 5b Id1! .Vli |-|-l. \,,\, \ <‘ , \ . |c(3.'.al..lc .. \ / CONCLUSIONS: 1. 2. 3. 4. 6. .7. 9. 10. The total count and colon index did not parallel the bathing loads in a natural bathing place as closely as did the streptococcus index. The most reliable measure of pollution was obtained in the area of the most dense bathing. Places free from bathing pollution showed no strepto- cocci. The streptococci disappeared Over night. Eggh. 221; did not disappear from the lake during the warmer months. Sand samples did not give information concerning pollu- tion introduced by bathers. Total counts and colon indices usually decreased over night, though occasionally increases were noted. Total counts and colon indices did not differ materially from those obtained in areas free from pollution. The streptococcus is recommended as an index of the pollution introduced by bathers into a natural bathing place. Natural bathing areas should conform to swimming pool standards. 1. 2. 5. 4. 5. 6. 9. 10. 11. 12. - ~62- LITERATURE CITED 1932 Report of Joint Committee on Swimming Pools and Bathing Places. American Public Health Association and Conference of State Sanitary Engineers. Winslow, C.E.A. and beon, David. Bacterial Pollution of Bathing Beach Waters in New Haven Harbor. Ame Joure Hyg.8:no.3,299,1928. Prescott, 8.0. and Winslow, C.E.A. Elements of Water Bacteriology, 5th Edition, 1931. SCOtt’ WeJe Survey of Connecticut's Shore Bathing Waters. Am. Jour. Public Health 22:no.3,316,1932. Michigan Stream Control Commission. Coastline Pollution Surveys of Michigan, June 1933. Savage, WeGe Bacteriology of Tidal Mud. Joure Hyg05314391905e Jordan, E.0. The Bacterial Self Purification of Streams. Jour. Exp. Med.5:271,1900. Purdy, We Ce Activities of Plankton in the Natural Purification of Polluted Waters. Am. Jour. Public Health 18:468,1928. Purdy, W. C. and Butterfield, C. T. The Effect of Plankton Animals upon Bacterial Death Rates. Am. Jour. Public Health 8,499,1918. Savage, W.G. and Read,W.J. Significance of Streptococci in Water Supplies. Joure Hyg015333491916e Irons, EoEe Neutral red in Routine Examination of Water. Jour. Hyg.2:314,l902. Jordan, E. 0. Special Report of Mass. State Board of Health on Purification of Sewage and Water, 1890. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. Winslow, C.E.A. and Hunnewell,M.P. Streptococci Characteristic of Sewage and Sewage- polluted Waters, apparently not hitherto Reported in America. Science,l5:827,l902. Houston, A.C. Bacterioscopic Examination of Drinking Water, with Particular Reference to Relations of Streptococci and Staphylococci with Waters of this Class. Report of the Medical Officer to Local Government Board for 1898-1899,page 467. London, England. Houston,A.C. 0n the Value of Examination of Water for Streptococci and Staphylococci with a view to detection of its Recent Contamination with Animal Organic Matter. Report Of Medical Officer of Local Government for 1899-1900,London:,England. Horrocks, W.H. Bacteriological Examination of Water. London, 1901. Savage,W.G. and Wood,D.R. The Vitality and Viability of Streptococci in Water. Jour. Hyge 16 3ND. 3,227,191.70 Prescott, 8.0. and Baker, S.K. The Cultural Relations of Bacillus coli and Houston's Sewage Streptococci and a Method for the Detection Of these Organisms in Polluted Waters. Jour. Infect. Dis.1:l93,1904. Rivas,D. E, coli communis, "The Presumptive Test," and the Sewage Streptococci in Drinking Water. Jour. Med. Res.16:85,1907. Rivas ,1). Preliminary Report of the Predominating Micro- organisms in Feces and Sewage, as an Index of Pollution in Drinking Water." 26th Ann. Rep. on Results of Chemical and Bacteriolo- gical Examination of London Waters. December, 1931. Mallmann, W.L. Streptococcus as an Indicator of Swimming Pool Pollution. Am. Jour. Public Health 18:77l,l928. 23. 24. 25. 26. -64- Mallmann, W.L. and Gelpi, A.G. Chlorine Resistance of Colon Bacilli and Streptococci in a Swimming Pool. Michigan. Eng. Exp. Sta. Bull. No. 27,1930. Report of the Joint Committee on Bathing Places of the American Public Health Association and Con- ference of State Sanitary Engineers. Am. Jour. Public Health 16:1186,1926. Standards Methods of Water Analysis. 7th Edition, 1933. Baker, Wop. Application of Swimming Pool Sanitation to the Public Bathing Beach. Jour. Am. Med. Assoc. 80:No.13,907,1923. M'TITI'ITIQHIIMII‘JILITHEELI'IZIIZITIJWIZITII‘I‘ITI