LAKE MICHIGAN STUDIES
Special Report Number IM 5
MICROBIOLOGICAL INVESTIGATIONS
April 1963
U. S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE
Public Health Service
Division of Water Supply and Pollution Control
Great Lakes-Illinois River Basins Project
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TABLE OF CONTENTS
INTRODUCTION 1
PROJECT INVESTIGATIONS 2
Parameters 2
Field Procedures 3
Laboratory Procedures 3
Findings k
Discussion and Significance of Findings 8
OTHER MICROBIOLOGICAL DATA 10
Coliform Densities at Various Drinking Water 10
Intakes and Bathing Beaches
Pollution Persistency 12
ULTIMATE SURVIVAL OF PATHOGENS IN LAKE MICHIGAN Ik
Possible Effect of Returning Treated Effluent 15
to Lake Michigan
CONCLUSIONS 17
REFERENCES 18
TABLES
FIGURES
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LIST OF TABLES
TABLE
1 Colifora Results From Deepwater and. Inshore Studies
2 20CC Total Plate Count Results From Deepwater and
Inshore Studies
3 35°C Total Plate Count Results From Deepwater and
Inshore Studies
k Coliform Results From Harbor Studies
5 20°C Total Plate Count Results From Harbor Studies
6 35 °C Total Plate Count Results From Harbor Studies
7 Coliform Levels at Three Points Adjacent to Central
District Filtration Plant, Chicago, Illinois, 196l
8 Coliform Incidence at the Chicago Beaches, Summer, 1961
9 Coliform Bacteria Per 100 ml at Dunne Crib in 1951,
1956, and 1961
10 Summary of Coliform Levels at Dunne Crib for 196"l
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LIST OF FIGURES
FIGURE
1 Distribution of Coliform Bacteria per 100 ml, S,W. Quadrant
of Lake Michigan
2 Distribution of Coliform Bacteria per 100 ml, S,E. Quadrant
of Lake Michigan
3 Distribution of Coliform Bacteria per 100 ml, Northern
Half cf Lake Michigan
h Coliform Densities in 10 Mile Zone Along West Shore of
Lake Michigan
5 Coliform Densities in 10 Mile Zone Along East Shore of
Lake Michigan
6 20°C Total Bacterial Densities in 10 Mile Zone Along
West Shore of Lake Michigan
7 20°C Total Bacterial Densities in 10 Mile Zone Along
East Shore of Lake Michigan
8 35°C Total Bacterial Densities in 10 Mile Zone Along
West Shore of Lake Michigan
9 35°C Total Bacterial Densities in 10 Mile Zone Along
East Shore cf Lake Michigan
10 Distribution of 20°C Total Bacteria per 100 ml,
S.¥, Quadrant of Lske Michigan
11 Distribution of 20°C Total Bacteria per 100 ml,
SoE. Quadrant of Lake Michigan
12 Distribution of 20°G Total Bacteria per 100 ml,
Northern Half of Lake Michigan
13 Distribution of Colifora Bacteria per 100 ml in
Chicago Harbor
Ik Distribution of Coliform Bacteria per 100 ml in
Bacino Harbor
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LIST OF FIGURES (cont.)
15 Distribution of Coliform Bacteria per 100 ml in
Milwaukee Harbor
16 Distribution of 20°C Total Bacteria per 100 ml in
Chicago Harbor
IT Distribution of 20°C Total Bacteria per 100 ml in
Eacine Harbor
18 Distribution of 20°C Total Bacteria per 100 ml in
Racine Harbcr
19 Location of Chicago Drinking Water Intakes and Beaches
20 Survival of Coliform Bacteria and Fecal Streptococci
in Lake Michigan Water at 25°C with Illumination
21 Survival of Coliform Bacteria and Fecal Streptococci
in Lake Michigan Water at 25°C Without Illumination
22 Survival of Coliform Bacteria and Fecal Streptococci in
Lake Michigan Water at 5°C Without Illumination
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INTRODUCTION
This report is based on (l) a preliminary study of the micro-
biology of Lake Michigan conducted by the Great Lakes-Illinois
River Basins Project during the spring, summer, and autumn months
of 1962 (April-December); (2) a review of raw water data of several
water plant intakes withdrawing water from Lake Michigan; (3) data
from samples of bathing beach waters in the Chicago area; and (4)
laboratory studies of survival of coliform and fecal streptococci
in Lake Michigan water.
The study of the microbiology of Lake Michigan conducted by
the Great Lakes-Illinois River Basins Project was achieved through
a series of eight cruises on vessels equipped with laboratories for
performing microbiological procedures. It was thereby possible to
process all samples immediately for analysis of bacterial content.
The locations of sampling stations are shown in Figures 1, 2, and 3
of the present report.
The raw water data review consisted of an analysis of data
obtained from records of certain water treatment plants in the
Chicago area. The bathing beach data were obtained from the Chicago
Park district, and the survival studies were carried out by the
Great Lakes-Illinois River Basins Project laboratory.
The purpose of the present report is to present the findings
on the present status of the microbiology of Lake Michigan and to
discuss the possible effects of returning treated sewage effluent
from the City of Chicago to Lake Michigan.
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PROJECT INVESTIGATIONS
The objective of the microbiological program was to determine
the present water quality of Lake Michigan in terms of bacterial
parameters. Qualitative and quantitative aspects were incorporated
so that the distribution of the pertinent bacterial varieties with
respective densities throughout might be ascertained. The various
determinations utilized were selected to indicate the sanitary
quality of the water as well as general biological productivity.
Parameters
Analyses were made for coliform content, and for total plate
counts at 20°C and 35°C. In certain of the harbor studies, some of
the samples were analyzed for fecal streptococcus content. Approxi-
mately 1,^00 samples comprised the coliform study. Total plate
counts at 20°C and 35°C were made on approximately l,i(-00 samples.
Coliform bacteria are defined in Standard Methods for the
Examination of Water and Wastewater (l)* as "including all of the
aerobic and facultative anaerobic, Gram-negative, non-sporeforming,
rod-shaped bacteria which ferment lactose with gas formation within
48 hours at 35°C.
Coliform organisms are significant to water quality since
these bacteria occur in the fecal matter of all warm-blooded
animals, including man. Consequently, the presence of coliform
bacteria in a body of water is interpreted as indicative of
contamination of the water by fecal matter. Since contamination
of water by fecal matter is one avenue of transmission of certain
water-borne diseases to humans, coliform bacteria are utilized as
indicators of possible pathogenic contamination. Increasing
densities of coliform bacteria found in water are, therefore,
related to the increasing degree of pollution of enteric origin
and to increasing health hazard to those exposed to the water.
Fecal streptococci, as used in the present study, includes
any species of streptococci commonly present in significant numbers
in the fecal excreta of humans or other warm-blooded animals (2).
Streptococci are Gram-positive cocci occurring in chains composed
of varying numbers of cells. These organisms may be parasitic or
saprophytic. The fecal streptococci, like the coliform bacteria,
*See references listed at end of report.
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are enteric organisms abounding in the fecal matter of all warm-
blooded animals; they likewise indicate the presence of fecal matter
in water. Fecal streptococcus results augment coliform findings in
that the streptococci indicate recent fecal contamination of water,
whereas the coliform bacteria may derive from more remote contamination.
Total plate counts, according to Standard Methods (l), are
approximate enumerations of total bacteria multiplying at temper-
atures of 35°C and 20°C on any one of several nutrient agars; they
yield useful information concerning the quality of the water tested
and may provide supporting data regarding the significance of the
results of the coliform test. (The medium of choice for the present
investigations was tryptone glucose extract agar.)
Total bacterial densities in water correspond to the decompo-
sition of organic matter. In this large group there are species which
grow well at several incubation temperatures. These are present in
most waters in small numbers and, in waters enriched with organic
matter, they occur in great abundance. Several species of this group
grow best at temperatures ranging from 5°c to 20°C. Other species
have become semi-parasitic,being especially adapted to the decompo-
sition of organic matter in the intestines of warm-blooded animals.
These latter forms develop most actively at body temperatures (35°C
to 37°C) (15).
Field Procedures
The samples were collected at each station at fixed depths:surface
(designated "0" meters), 5, 10, 20, 30, 50, 75* 100* 150, and 250 meters,
The number of samples at a given station was therefore determined by the
depth of the lake at that point. The deepest samples collected at a
station are referred to in this report as "lowermost." The samples
were collected in three zones: deep water, inshore, and city harbors.
The inshore investigations utilized samples collected at intervals of
1 mile, k miles, and 10 miles offshore. The inshore work was devoted
largely to the southern, half of Lake Michigan.
All bacterial samples were collected in Zobell J-Z water samplers,
permitting individual sample collections from the various depths in
sterile glass bottles which remained sealed until sampling depth was
reached.
Laboratory Procedures
All bacterial determinations were made in accordance with the
procedures set forth in Standard Methods for the Examination of Water
and Wastewater (l), Eleventh Edition, 196o7~ppT77-526, or in
accordance with modifications of these procedure as established through
research at the Robt.A.Taft Sanitary Engr.Center, Cincinnati, Ohio.
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k-
These latter modifications were related to the media constituents of
the streptococcus medium (2). Coliforra and fecal streptococcus
determinations and total plate counts were made "by the membrane
filter technique. Results for coliform, fecal streptococci, and
total plate counts are reported on the basis of number of organisms
per 100 milliliters (ml).
Findings
Deepwater and Inshore Studies
Coliform Findings. Table 1 shows that, of 313 surface samples
collected at the deepwater and inshore points, 134 (42.8$) contained
a density of less than 1 coliform bacterium per 100 ml. A total of
233 (?4.6$) samples contained 10 coliform bacteria or less per 100
ml and a total of 292 (93.4$) showed coliform densities of 100 or less,
An additional 17 samples showed coliform densities in the range of
100-1,000 per 100 ml. Only 4 samples (l.3$) exceeded 1,000 per 100
ml and these were in the range 1,000-2,000 per 100 ml. These latter
4 samples were from sampling points located within one mile offshore
and adjacent to Gary, Indiana, and Racine, Wisconsin. Also shown in
Table 1 is a summary of results from the deepest samples collected.
Examination of test results from all samples (approximately 1,400)
showed that, in general, variations in coliform density did not
reflect significant differences in water quality with respect to
depth. Therefore, further details of this aspect are not included,
The geographical distribution of the coliform densities derived
from the surface samples is shown in Figures 1, 2, and 3- An
examination of these map graphs shows that in the southern basin
the higher coliform densities are located adjacent to the shoreline
and correlate with the centers of urbanization. The western shoreline
from Milwaukee to Gary showed consistently higher coliform densities
than did the eastern shore. Beyond this zone of contamination, the
deep water in the majority of samples showed little or no coliform
content (reported as less than 1 per 100 ml). These relationships
are presented in Figures 4 and 5 showing coliform densities as they
were measured at intervals of 1 mile, 4 miles, and 10 miles offshore.
Diminishing coliform densities consistently occurred from one mile
offshore to 10 miles offshore around the periphery of the southern
half of Lake Michigan. All 10-mile samples from Gary, Indiana to
Muskegon, Michigan, failed to give positive coliform findings in
100 ml samples.
These findings, in general, indicate that the bacteriological
quality of Lake Michigan water is excellent where not locally
contaminated through domestic sewage entering the lake.
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Total Plate Count Findings. The bacterial densities of
species growing at 20UC and 35°C parallel those of the coliform
"bacteria. The lowest densities (100 to 500 per 100 ml) were found
in the central body of the lake (deep water). Highest densities
were observed in the inshore areas in relation to the geographical
location of cities and towns. (See Figures 6, 7, 8, 9, 10, 11,
and 12). Approximately 25% of the samples contained densities
(20°C and 35°C) greater than 10,000 per 100 ml.
Highest 20°C densities encountered were approximately 500,000 per
Z00~m3. (near Racine. Wisconsin, at 1 mile offshore). Other areas
showing densities in excess of 100,000 per 100 ml were offshore
from Milwaukee, Racine, Kenosha, Chicago and Michigan City.
The highest densities observed with the 35 °C test were in
excess of 500,000 per 100 ml. These occurred at Milwaukee, Kenosha,
and Gary. The highest 35°C density was approximately 1,300,000 per
100 ml approximately 7 miles off the Chicago waterfront.
Tables 2 and 3 show the per cent of samples which contained
various total densities. The cumulative per cent distribution of
the 20°C and 35°C total densities is also shown. Results in these
two tables originate from surface samples. The wide range in the
numbers present throughout the lake, and the considerable number of
samples showing high densities, are indicative of organic enrich-
ment of these waters.
Harbor Studies
Three city harbors were investigated: Chicago, Racine and
Milwaukee. Samples were collected in the immediate harbor area
and in the adjacent waters in a radial zone extending 3-5 miles
around the chief river mouth emptying into the harbor.
The highest coliform densities encountered were associated
with and located in the Milwaukee Harbor. The next highest
densities were found in the Racine Harbor area. The Chicago
Harbor area showed the least coliform occurrence of the three
harbors studied. Highest total plate counts occurred at those
stations showing highest coliform densities. Sampling stations
are shown in Figures 13, lU, and 15.
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Coliform Findings . Fifteen samples were collected from
15 sampling points in the Chicago Harbor study. All samples
contained fewer than 1,000 coliform bacteria per 100 ml, while
6 (86.7$) contained fewer than 500 coliform per 100 ml. Seven
of the samples (46. 1%} were in the 1-50 per 100 ml range and
3 (20.0$) of the samples were in the 1-10 per 100 ml range.
(See Figure 13 and Table 4).
The higher coliform levels ( 100-1, 000 per 100 ml) were
encountered in an area immediately adjacent to the mouth of the
Chicago River (both inside and outside the breakwater harbor)
and extending south of the harbor for approximately 2 miles in the
waters about one-half mile or less offshore.
In the Racine Harbor higher coliform densities were encountered,
with 38-2$ of the 3^ samples in the study containing coliform levels
in the range of 1,000-10,000 per 100 ml. The highest coliform
density (in the 5,000-10,000 per 100 ml range) was encountered at the
mouth of the Root River which empties into the breakwater harbor.
Coliform densities in the next lower range (1,000-5,000 per 100 ml)
were encountered at the harbor mouth and in a zone extending south
of the harbor mouth for approximately one mile in the waters which
were sampled approximately 1,500 feet offshore. However, the
remainder of the radial area surrounding the harbor for a distance
of one to two miles uniformly contained coliform densities in
100-1,000 per 100 ml range. (See Figure
The Milwaukee Harbor manifested the highest coliform densities,
with 15.9$ of a total of 76 samples tested containing coliform
bacteria in the 10,000-40,000 range. The highest coliform
densities (in the 10,000-40,000 per 100 ml range) were encountered
at the mouth of the Milwaukee River and within the breakwater in
the southern two-thirds of the harbor. The northern third of the
harbor contained coliform densities in the 1,000-10,000 range.
A breakwater leads south from the harbor for a distance of some
two miles. The coliform densities in the waters between this
breakwater and the shore progressively decreased from 5*000-10,000
per 100 ml at the harbor inlet to 100-1,000 per 100 ml where the
open water is reached. In the open waters adjacent to the harbor
breakwater, the northern area showed very little or no coliform
content. Most samples originating in the open waters surrounding
the southern half of the harbor breakwater contained coliform
densities ranging from 10-100 per ml at the central harbor mouth to
100-1,000 per 100 ml in the southern most waters adjacent to the
breakwater running south for approximately two miles. (See Figure
15).
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The bacterial findings at each of the harbors indicated that
the harbor waters mingle with the surrounding waters of Lake Michigan
and that the direction of- flow is to the south.
Fecal Streptococcus Findings. Fecal streptococcus deter-
minations were included in the Milwaukee and Racine Harbor studies.
The maximal density of fecal streptococci encountered in the
Milwaukee Harbor samples, originating from surface waters, was
19,000 per 100 ml. This sample was collected in the Harbor, just
north of mouth of the Milwaukee River. At the mouth of the
Harbor (opposite the mouth of the Milwaukee River) a fecal strepto- \
coccus density of 40 per 100 ml was observed. A level of 300 per
100 ml was observed at one point just south of the southern inlet
into the harbor. Samples in the open waters adjacent to the
northern half of the Harbor were reported as less than 10 per 100 ml.
The streptococcal densities from the Racine Harbor were 200
per 100 ml at the mouth of the Root River, with a density of 400
per 100 ml at the main Harbor mouth;in the waters south of the
harbor densities in the range of 10-610 per 100 ml were observed.
Observations to the north of the Harbor were 10 and 20 per 100 ml.
Total Plate Count Findings. As previously stated, the results
of the total plate counts agreed with the coliform findings, showing
high counts at sampling stations where maximum coliform densities
occurred and generally decreasing as coliform densities decreased.
In the Chicago Harbor study, 9 of the 17 samples showed total
densities in the 50,000-500,000 range as estimated by the 20°C
total plate count. The 35°C total plate count showed similar
total densities, with 9 of the 14 samples tested falling into the
50,000-500,000 per 100 ml range. The highest densities (300,000-
500,000 per 100 ml) occurred in the waters immediately outside
the breakwater and in the area extending approximately two miles
to the south and one-half mile or less offshore. (See Tables 5
and 6). The distribution of 20°C total bacterial densities in the
Chicago Harbor are shown in Figure 16.
In the Racine Harbor the total plate counts at 20°C gave rise
to estimations of higher densities than did the 35°C plate count.
93-7$ of 32 samples contained total densities in the 100,000-
1 million range as estimated by the 20°C total plate count, and
89.3/0 of the 28 samples tested at 35°C contained densities in the
10,000-500,000 range. Densities of approximately one million
(20°C) were encountered at the Root River mouth and throughout the
harbor. (Figure 17). The entire one-to-two-mile radial zone ,
around this haroor contained total 20°C densities of approximately /
200,000 per 100 ml. /
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The Milwaukee Harbor showed the highest total bacterial
densities of the three harbors herein discussed. Of 75 samples,
32 (42.7$) contained densities in the 50,000 to less than 1 million
range as estimated by the 20°C total plate count (Figure 18) and
30 (40.0$) of 75 samples were in the same range as estimated by the
35°C total plate count. Densities of 1,300,000 to 1,500,000 per
100 ml (20°C) were encountered at the mouth of the Milwaukee River
and in the central one-third of the Harbor. The corresponding
35°C density at the river's mouth was 2,200,000 per 100 ml. At the
extreme northern end of the harbor the total densities were 180,000
and 140,000 (20°and 35°C, respectively). At the southern extremity
of the harbor the respective densities were 170,000 and 130,000.
In the breakwater zone south of the harbor the 20°C densities
progressively diminished from 260,000 per 100 ml to 48,000 (at
open water). The 35°C densities diminished from 210,000 to 24,000
throughout the same area. In the open waters adjacent to the
northern portion of the harbor much lower densities were often
observed (from 10,000 to only a few hundred per 100 ml on both 20°
and 35 °C tests). The densities at the central harbor mouth were
13,000 and 7,200 (20° and 35°C, respectively). This latter
situation may indicate prevailing inflow of Lake Michigan water
at the harbor mouth. In the open waters along the breakwater
extending south of the harbor, 20°C .densities were fairly constant
at approximately 30,000 per 100 ml. The 35°C densities in the
same area were somewhat lower (28,000 to 9,700). (See Tables 5
and 6).
Discussion and Significance of Findings
From the above findings, it is apparent that the bacterial
quality of Lake Michigan water is generally good in deep water and
is more degraded in varying degrees along ilia shoreline and in
city harbors. The coliform findings indicate the presence of
pollution of fecal origin in these shoreline and harbor areas,
showing increased densities with respect to sampling stations
located in these areas.
At a distance of 1 mile offshore along the western shore from
Milwaukee, Wisconsin, to Gary, Indiana, the coliform levels were
frequently in the 100-1,000 per 100 ml range, representing sub-
stantial pollution in the 1 mile zone. The highest coliform
densities were encountered in water contiguous to the towns of
Milwaukee, and Racine, Wisconsin; Chicago, Illinois; and Hammond,
and Gary, Indiana. The water quality was much less degraded in
the northern half of Lake Michigan.
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The coliform and fecal streptococcus findings in the Milwaukee
Harbor indicate the presence of gross pollution. The same may be
said of the Racine Harbor as veil as of the waters adjacent to
Whiting and Gary, and Hammond, Indiana, although the pollution
encountered was not as intense as that of the Milwaukee Harbor.
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OTHER MICROBIOLOGICAL DATA
Collform Densities at Various Drinking Water Intakes and
Bathing Beaches
In addition to the data collected by the Great Lakes-Illinois
River Basins Project, daily water sampling results at the various
city water intakes as well as routine sampling of "bathing beaches,
gives much additional information on prevailing quality as veil as
the occurrence of sudden and localized deteriorating influences.
Tables 7 and 8 are included to show the presence of coliform densities
occurring at substantially higher levels than encountered in the
Great Lakes-Illinois River Basins Project cruises. Additional micro-
biological aspects pertinent to the evaluation of the present and
future quality of the waters of Lake Michigan are to be found in the
discussion below.
From the records of the water treatment plants at Chicago and
Evanston, Illinois (3, 4), it is indicated that the water of Lake
Michigan is of good bacterial quality as long as pollution from
domestic sewage inflows is not present. Bacteriological samples
collected at the water intakes at the Chicago and Evanston water
treatment plants often have shown coliform density of less than
2.2 per 100 ml. At times, however, evidence of pollution of varying
degrees is encountered at the water intakes (located one to four
miles offshore), as judged by coliform content. (See Figure 19 for
location of the Chicago water intakes). Such increase in pollution
is reported to be encountered at the Dunne Crib when the prevailing
winds are southerly. The pollution accruing from the cities located
at the southern tip of the lake, as well as polluted water from the
Calumeg-Sag Channel and other points flowing into Lake Michigan during
heavy rainfalls, thus is introduced into the water intake of the
City of Chicago's South District Filtration Plant (Dunne Crib).
This polluted water often bears marked phenolic tastes and odors
believed to originate in the industrial and other wastes introduced
into the lake along with the domestic sewage cited above.
Table 9> comprised of data from the official records of the
City of Chicago, summarizes variations in prevailing water quality
in terms of the coliform content encountered at Dunne Crib for the
years 1951* 1956, and 196l, as examples typifying conditions in
past records. The total number of days when the coliform density
(MPN per 100 ml) was 2.2 or less per 100 ml were: 1951, l86j
1956, 90; and 1961, 174. Days when the coliform density was 50 or
greater were as follows: 1951? H days; 1956, 48 days; and 1961,
54 days. The maximum coliform densities encountered in 1951? 1956,
and 196l were 374, 1100, and 3000 per 100 ml, respectively.
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n
The maximum coliform density reported at the Evanston water
treatment plant for 1956 was 23,000. This density was encountered
on the following dates: January 10, 12, 13, 17; September—1 day;
November 2k, 25, 29; and December 15, 21, and 25 (4).
Inspection of coliform levels at these two locations,separated
by 20 miles, but both located on the west shore of Lake Michigan,
near heavily populated metropolitan areas, reveals great variation
and lack of homogeneity in the distribution of coliform bacteria
present in Lake Michigan water, particularly when a density of
23,000 per 100 ml prevailed for more than one day consecutively at
Evanston and nothing comparable was detected simultaneously at the
Dunne Crib.
Earlier records show that heavily contaminated water would reach
and travel past Dunne Crib as in the years 19^0, 194l, 19^2, when
isolated coliform levels of 300,000 were detected. On October 19,
a maximum of 300,000 coliform per 100 ml was detected in the Dunne
Crib intake, while an adjacent water intake located only 300 feet
closer to shore and sampled within 15 minutes, showed a level of
2^00 coliform per 100 ml (3). Pollution in this order of magnitude
was known to originate in cities located at the southern tip of
Lake Michigan which contributed large amounts of domestic and industrial
wastes to Lake Michigan. Improvements in these local conditions
resulted in sharply reduced maximum coliform levels reaching the
Dunne Crib in subsequent years. It was this degraded water quality
in the southern end of Lake Michigan that determined the need for
and location of the City of Chicago's first water filtration plant
(the South District Filtration Plant, put into service in 19^) (6, p. 15).
Table 7 presents data revealing the coliform densities that
prevailed during the months of June-November, 1961, inclusive, at three
locations adjacent to the north side of the City of Chicago's Central
District Filtration Plant, currently under construction (3)« It will
be noted that the levels of coliform at all points exceeded the
recommended maximum of 50 to 100 coliform bacteria per 100 ml for
source water to be used for public water supplies where chlorination
is the only treatment provided (7, p.ll). The maximum MPN per 100 ml
reported from these points was 24,000.
The range of commonly accepted standards established by States
for water to be used for swimming and other recreational uses is
50 to 2kOO coliform bacteria per 100 ml (ih). Table 8 presents the
coliform levels occurring at each of the beaches located on the
Chicago lakefront during the summer of 1961 and is based on samples
collected during the months of May through September at each sampling
point (5). The southern-most beaches show days of gross pollution
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with Most Probable Numbers (MPN) greater than 110,000. Three points
on the Calumet Beach showed MPN's per 100 ml in excess of 1,000
in 70$ of the samples collected. Beaches at Hammond and Whiting,
Indiana showed 72$ of samples in excess of 1,000. The range for
the other 2k beaches was 19-60$ wherein MPN's per 100 ml were detected
in excess of 1,000. The highest MEN per 100 ml detected was 240,000
occurring at 12th Street Beach on September 15, 196! in the wake of
the polluted water backflowing through the locks into Lake Michigan
(see discussion below).
Pollution Persistency
The material and data presented above demonstrate the lack of
uniformity in the quality of Lake Michigan water, wherein local areas
of the lake show excessive pollution, as measured by the coliform MPN,
and other areas, either adjacent or more removed, may show quite
low colifcn content. Polluted slugs of water entering the lake are
not immediately dispersed and tend to maintain xueir identity for
days. The latter condition has been demonstrated when the locks on
the Chicago River have been opened to alleviate flood conditions in
the Upper Illinois Waterway.
The locks at the Chicago River were opened to release flood
waters on September 14, 1961. At the same time flood water was
released from the Upper Illinois Waterway through the locks at the
upper end of the North Shore Channel at Wilmette, Illinois. At the
southern end of Lake Michigan, massive amounts of flood water entered
the lake from the Calumet River when the direction of flow in the
river was reversed in response to the heavy rainfall. A survey to
determine the location, migration, and persistency of the flood water
introduced into Lake Michigan,was undertaken by the Great Lakes-Illinois
River Basins Project (8). The discharge from the Chicago River was
more intensively studied than the other two massive discharges.
Testing and identification of the polluted water was maintained in
terms of coliform and fecal streptococcus levels (membrane filter
determinations). Coliform densities per 100 ml in the magnitude of
180,000-150,000 were encountered 1 3/8 and 7/8 miles, respectively,
offshore opposite the mouth of the Chicago River, the first day,
with slight diminution on the second day, and a maximum of 11,000
appearing on the third day. On the third day a density of 320.000 was
encountered to the north near Wilson Avenue Crib (water intake).
This body of polluted water may have originated from the flood water
released concurrently on September 1^, 196l, from the North Shore
Channel at Wilmette.
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The bacteriological findings of this investigation indicated
that the polluted flood water tended to maintain its identity for
at least 3 days and was kept fairly close to its point of intro-
duction (around the mouth of the Chicago River) by the prevailing
winds. A tongue of polluted water appeared to extend some 4 miles
in a southerly direction from the point of heaviest concentration
of pollution.
The normal quality of Lake Michigan water in the Chicago area
was apparently influenced by the heavy rainfalls and subsequent
run-off which occurred during September. 1961. The total precipita-
tion recorded at Midway Airport (1^.17") was the heaviest for any
month of record at this station (1928-1961). The Chicago Avenue
and Wilson Avenue Control Stations of the Chicago water department
as well as Dunne Crib, reported sustained periods of high chlorine
demand occurring throughout the remainder of September, October,
and November. Table 10 summarizes the change in coliform content
of water taken in at Dunne Crib throughout the year of 196"!, with
the exception of December. It is apparent that higher levels of
coliform bacteria were encountered in September, October, and November
at greater frequency than at any other period of the year.
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ULTIMATE SraVTVAL OF PATHOGENS IN LAKE MICHIGAN
The question of ultimate survival of "bacteria, including
pathogens, artificially introduced into Lake Michigan (through
sewage effluents, flood water overflow from polluted sewers, etc.)
is one of great importance and is of particular significance in
relation to public health and safety. Pathogenic forms such as
typhoid organisms have been known to survive winter conditions in
northern locations, travel downstream following thaws and subse-
quently precipitate epidemics among water users (9). Pathogenic
enteroviruses have been shown to be much more resistant to
chlorination than are vegetative bacterial cells, and may be
presumed to be persistent in nature until proven otherwise (10,
16, I?). Other enteric parasites (such as Endamoeba histolytica
and nematode eggs) are knovuto survive outside the human intestinal
tract and to be more resistant to chlorination than the sewage
indicator organisms, the colifora group (10).
Little information is available on the survival of any of
these forms, including the colifora,bacteria in Lake Michigan.
The very nature of the problem and the peculiarities of microbial
survival and reproduction render field investigations extremely
difficult since no known method is available on a practical basis
to follow a given inoculum of bacteria through the many depths and
currents of a body of water like Lake Michigan. Moreover, the
introduction of pathogenic forms into a body of water used as a
source for public drinking water for study purposes is not tenable.
Laboratory studies cannot easily duplicate the conditions found in
nature. Nonetheless, such studies do provide useful information in
considerations related to survival of enteric microorganisms in
nature. While many laboratory studies relating to the survival
of pathogenic forms in either laboratory or natural conditions can
be cited, one survival study on Shigella sonnei seems particularly
noteworthy. In this rtudy £>. sonnei remained viable when stored
in tap water for 211 days (ll). In another investigation Salmonella
typhosa was found to survive in impounded surface water up to
26 days (12).
A survival study using Lake Michigan water was conducted in the
laboratories of the Great Lakes-Illinois River Basins Project wherein
the survival of coliform and fecal streptococci was investigated. In
this experiment, Lake Michigan water was collected 20 miles offshore.
Initial coliform measurements on the water as collected were less than
one coliform cell per 100 ml, with no fecal streptococci detected.
This water was seeded with untreated sewage collected from the West-
Southwest Treatment works and transferred to sterile gallon jugs. These
containers were stored at the following temperatures and conditions:
-------
-------
15
(l) 25°C with room illumination during vorking hours
(2) 25°C in the dark, and
(3) 5°C in the dark.
Under each of these test conditions, the fecal streptococci showed less
survival capacity than did the coliform bacteria. Initial streptococcus
levels were in the ranges of 680,000 to 1,000,000 cells/100 ml. At 25°C
with light, no streptococci were detected at the end of 5 days. In the
dark at 25°C, 2 per 100 ml were measured at the end of 15 days, and at
5°C in the dark, 3^0 per 100 ml were viable at the end of 15 days.
Determinations for both the streptococci and coliform were via direct
colony count using membrane filter techniques.
Initial levels of coliform were approximately 50Q,OQQ in each of
the test containers. At the end of 15 days the following levels were
detected as still viable: (l) 25°C with light, 3400 per 100 ml;
(2) 25°C dark, 7^00 per 100 ml, and (3) 500 dark, 11,000 per 100 ml.
Under the conditions of (2) the coliform bacteria underwent an initial
increase of 30$ at the end of the first day and under the conditions of
(3) a 50$ increase by the end of the fifth day. Following these peaks,
the numbers decreased without interruption through the 15-day test
period. These results are set forth in Figures 20, 21, and 22. While
this study was a small investigation, and exploratory in nature, its
immediate significance lies in the fact that bacteria from Chicago
sewage wastes were combined with Lake Michigan water on a test basis.
The results wherein coliform survived at 5°C through 15 days (and would,
no doubt, have been detected as viable for a more extended period had
the test not been terminated at the end of 15 days) are of particular
importance if the same or greater survival rate should prevail from
sewage bacteria introduced into Lake Michigan. It has been observed in
some areas (13) that residual bacteria remaining viable in partially
chlorinated sewage treatment plant effluent may multiply in great
numbers in the waters receiving the effluent. This rapid multiplication
occurs since competitors for the food supply (other bacteria and other
microbial forms) and predators are killed off, leaving the residual
bacteria surviving uninhibited in an environment rich in the nutrients
upon which they thrive. Currents and wave distribution could, under
certain conditions, carry such contamination to the vicinity of water
intakes and bathing beaches within a few days at most.
Possible Effect of Returning Treated Effluent to Lake Michigan
The possible effect of returning sewage effluent produced by the
MSB plants to Lake Michigan is complex, with manifold ramifications.
The factors relating to the fate or survival of pathogens introduced
into the lake are largely unknown. Distribution and survival of living
pathogens, both surface-wise and depth-wise, cannot, at the present time,
be intelligently discussed since little information is available relating
to both the functioning of the biological entities in question and the
physical and limnological characteristics of Lake Michigan.
-------
-------
16
It can be proposed, however, on the basis of available information
that the addition of sewage effluent from the MSB plants would contri-
bute to the deterioration of the microbiological quality of
Lake Michigan water. It has been observed that under certain conditions
polluted water may maintain its identity and move in discrete masses
within the lake. It is reasonable to assume that drinking water intakes
and bathing beaches would, at times of varying frequency, be influenced
by water of objectionable quality. On many days in the bathing season
of 1961 the present water quality at several of the Chicago beaches had
very high coliform levels. Any addition to the prevailing levels of
pollution could be expected to seriously menace this use of Lake Mich-
igan. The same observations would apply to the lake as a source of
public water supplies.
-------
-------
17
CONCLUSIONS
1% The colifonn concentrations in certain areas of Lake Michigan
water at times exceed the level regarded as the safe limit
for water used as a source of public water supply where
chlorination is the only treatment provided,
2. The most recent records of the quality of Lake Michigan water
at points up to two arcl one-half miles offshore in the vicinity
of Chicago bathing beaches show that coliform concentrations are
often in excess of acceptable limits for swimming and other
recreational use3»
3« Coliform densities are so high in city harbors and adjacent areas
studied, tliet a grave threat to health mus'u be presumed to exist
through coi.itact with these waters.
k. The fecal streptococcus levels, as well as the coliform bacteria,
indicate gross pollution in the harbors studied.
5. Lowest total bacteriel densities were observed in the central body
of lake water with increasing densities occurring in relation to
the placement of cities and towns. Increasing total bacterial
densities usually indicate deterioration in the sanitary quality
of water through the presence of pollutants contributing to the
enrichment of the water,
6. Masses of bacterially-poHvited water introduced into Lake Michigan
may maintain their identity for several days.
7* It is known that mic:.:obial forms pathogenic to man survive in
netural bodies of water for varying periods; some forms may be
able to surviva longer than the indicator organisms commonly used,
i.eo, the coliform bacteria»
8. The return to Lake Michigan of sizab.le quantities of treated waste
waters, now being discharged to the Illinois River, would increase
the densities of colifcrm bp.cteria and other microbiai forms in the
vicinity of the outlet, 1'bis would increase the potential hazards
to public health in the use of waters in the area, and heighten
the need for protective measures - including, but not limited to:
complete treatment of waste waters "before discharge to the Lake
and complete treatment of municipal supply taken from the Lake.
-------
-------
18
REFERENCES
Methods for the Examination of Water and Wastewater.
Eleventh Edition. American Public Health Association, Inc.
New York, N.Y. (1960).
2. Recent Developments In Water Bacteriology. U.S. Department of
Health, Education, and Welfare; Public Health Service; Division
of Water Supply and Pollution Control; Robert A. Taft Sanitary
Engineering Center, Cincinnati, Ohio. (1961).
3. City of Chicago Water Department. Unpublished Water Quality
Data Records.
k. City of Evanston Water Department. Unpublished Water Quality
Data Records.
5. Chicago Park District. Unpublished Water Quality Data Records.
6. U.S. Public Health Service. The Chicago Cook County Health Survey.
Columbia University Press. New York.
7. U.S. Public Health Service. Manual of Recommended Water Sanitation
Practice. Public Health Service Publication No. 5257 CL95&J-
8. U.S. Public Health Service. Movements .in Lake Michigan of Water
Discharged ]A September 1961 from The Chicago Sanitary Canal System,
U.S. Exhibit No. 4, Chicago Diversion Case, Mimeo, Unpublished (196!) ,
9« Healy, W.A. and Grossman, R.P. Water-Borne Typhoid Fever Epidemic
at Keene, New Hampshire. J. New England Waterworks Association,
75:38 (1961).
10. Kabler, P.W. ; Clark, H.F.; and Clarke, N.A. Pathogenic Micro-
organisms and Water- Borne Disease. Proceedings Rudolfs Research
Conference; Public Health Hazards of Microbial Pollution of Water.
Dept. of Sanitation, College of Agriculture, Rutgers University.
(1961). pp. 9-56.
11. Kraus, P., and Weber, G. Investigations on the Viability of
Pathogenic Organisms in Water Supplies and Surface Water.
Zbl. Bakt. I, 171:509 (1958).
12. Shrewsbury, J.F.D., and Barson, G.J. A Note on the Absolute
Viability in Water of S. Typhi and the Dysentery Bacilli.
Brit. Med. Jour., 1:95^ (1952).
-------
-------
19
REFERENCES (cont.)
13. Rudolfs, W., and Gehm, H.W. Multiplication of Total Bacteria
and B. coli after Sewage Chlorination. Sewage Works
Journal 7:991 (1935).
14. State Water Pollution Control Board. Water Quality Criteria.
Sacramento, California. 1957.
15. Prescott, S.C.; Winslow, C.A.; and McCrady, M. Water Bacteriology.
John Wiley and Sons, Inc. New York. (1950).
16. Rhodes, A.J.; Clark, E.M.j Knowles, D.S. and Goodfellow, A.M.
Prolonged Survival of Human Poliomyelitis Virus in Experimentally
Infected River Water. Canad. Jour. Pub. Health, iO.:l46 (1950).
17. Gilcreas, F.W. and Kelly, S.M. Relationship of Coliform-Organism
Test to Enteric Virus Pollution. Jour. Amer. Wat. Wks. Assn. 47:683
(1955).
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TABLE 8
COLIFORM INCIDENCE AT THE CHICAGO BEACHES, SUMMER, 1961*
BEACH
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
Juneway Terrace
Rogers Ave.
Howard Street
Sherwin Ave.
Rogers Park
Farwell Beach
Pratt Blvd.
Columbia Ave.
North Shore Ave.
Albion Ave.
Granville Ave.
Thorndale Ave.
Hollywood Ave.
Foster Ave.
Montrose Beach
North Ave. (North)
North Ave. (South)
Oak Street
12th Street
31st Street
49th Street
57th Street
Jackson Park
67th Street
Rainbow (North)
Rainbow (South)
Calumet (Outer)
(North)
(South)
Calumet
Calumet
Hammond
Whiting
SAMPLING
POINT
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
COLIFORM
MAX
1,500
12,000
11,000
> 110,000
110,000
46,000
4,600
> 11,000
15,000
11,000
7,500
21,000
7,500
24,000**
24,000**
15,000
> 110,000
15 ,000
240,000**
46,000
> 1,100
4,600
46,000
4,600
110,000
> 11,000
46,000
> 110,000
> 110,000
> 110,000
> 110,000
MPN/100
No . days
at Max.
1
1
1
2
1
1
1
1
1
1
1
1
1
1
1
3
1
1
1
1
1
2
1
1
1
1
1
1
1
2
2
ml
No. days
> 1000
5
10
9
8
8
9
6
5
5
6
10
7
9
11
16
8
10
12
17
10
5
12
12
9
10
10
15
18
22
20
19
**9-15-6l
*Data supplied by the Park District, City of Chicago
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TABLE 10 Summary of Coliform Levels at Dunne Crib
for 1961 (MPN/100 ml)
JANUARY
FEBRUARY
MARCH
APRIL
MAY
JUNE
JULY
AUGUST
SEPTEMBER
OCTOBER
NOVEMBER
DECEMBER
Number
Having
** 2.2
24
23
10
19
16
18
5
13
2
1
0
of Samples
an MPN of
> 50
0
0
3
3
8
0
1
0
9
18
14
Maximum
MPN
During Month
10.0
6.9
120.0
88.0
510.0
33.0
120.0
44.0
450.0
1800.0
3000.0
Data Supplied by: Department of Water and Sewers, City of
Chicago
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LEGEND
-• I Mile Stotions
— —O 4 Mile Stations
• - —D !0 Mile Stations
MILW.
GARY
AREA REPRESENTED
GREAT LAKES 8 ILLINOIS
RIVER BASINS PROJECT
COLIFORM DENSITIES
IN 10 MILE ZONE ALONG WEST
SHORE OF LAKE MICHIGAN
DEPT. OF HEALTH, EDUCATION, a WELFARE
PUBLIC HEALTH SERVICE
REGION V CHICAGO, ILLINOIS
FIGURE 4
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LEGEND
• • I Mile Stations
O— O 4 Mile Stations
NOTE—
All samples from 10 mile contour contained
coliform densities of less than I per 100ml,
Therefore no 10 mile contours are shown on
this graph i
MUSKEGON
AREA REPRESENTED
GREAT LAKES 8 ILLINOIS
RIVER BASINS PROJECT
COLIFORM DENSITIES
IN 10 MILE ZONE ALONG EAST
SHORE OF LAKE MICHIGAN
OEPT. OF HEALTH, EDUCATION, a WELFARE
PUBLIC HEALTH SERVICE
REGION V CHICAGO, ILLINOIS
FIGURE 5
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u_
o
UJ
m
LEGEND
-• I Mile Stations
04 Mile Stations
• O 10 Mile Stations
MILW.
GARY
AREA REPRESENTED
GREAT LAKES 8 ILLINOIS
RIVER BASINS PROJECT
20° C TOTAL BACTERIAL DENSITIES
IN 10 MILE ZONE ALONG WEST
SHORE OF LAKE MICHIGAN
DEPT. OF HEALTH, EDUCATION, 8 WELFARE
PUBLIC HEALTH SERVICE
REGION V CHICAGO, ILLINOIS
FIGURE 6
-------
1,000
IOC
o
o
a:
UJ
o.
tr
UJ
o
<
00
IT
LL)
CD
LEGEND
-• I Mile Stations
O 4 Mile Stations
• D 10 Mile Stations
•GARY IND
AREA REPRESENTED
GREAT LAKES 8 ILLINOIS
RIVER BASINS PROJECT
20°C TOTAL BACTERIAL DENSITIES
IN 10 MILE ZONE ALONG EAST
SHORE OF LAKE MICHIGAN
DEPT. OF HEALTH, EDUCATION, & WELFARE
PUBLIC HEALTH SERVICE
REGION V CHICAGO, ILLINOIS
FIGURE 7
-------
1,000,1
o
o
a:
UJ
CL
tc
LJ
i-
o
<
CD
o:
UJ
CD
100,
10,
LEGEND
-• I Mile Stations
O— —
—O 4 Mile Stations
10 Mile Stations
MILW.
GARY
AREA REPRESENTED
GREAT LAKES 8 ILLINOIS
RIVER BASINS PROJECT
35°C TOTAL BACTERIAL DENSITIES
IN 10 MILE ZONE ALONG WEST
SHORE OF LAKE MICHIGAN
DEPT. OF HEALTH, EDUCATION, a WELFARE
PUBLIC HEALTH SERVICE
REGION V CHICAGO, ILLINOIS
FIGURE 8
-------
1,001
O
g
tr
CL
(£.
LoJ
O
<
03
U.
O
CC
UJ
CO
LEGEND
-• I Mile Stotions
O— O4 Mile Stations
10 Mile Stations
WD.
AREA REPRESENTED
GREAT LAKES 8 ILLINOIS
RIVER BASINS PROJECT
35°C TOTAL BACTERIAL DENSITIES
IN 10 MILE ZONE ALONG EAST
SHORE OF LAKE MICHIGAN
DEPT. OP HEALTH, EDUCATION, & WELFARE
PUBLIC HEALTH SERVICE
REGION V CHICAGO, ILLINOIS
FIGURE 9
-------
Fi g ur e 10
-------
6
2
f
p.
g
!
o
g.
o
o
o
o"
6
o
a
8
8-
o
I
o
o
o
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§
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o
to
o
CO
O
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or
to 2
* w
< *
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O
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i_
FIGURE II
-------
FIGURE f2
-------
o
o
o
in
o
10
(O
o
r^-
oo
Colif
LEGEND
)rm Density Per 100
HO
10-IOC
100-ljCOO
ml.
SREAT LAKES 8 ILLINOIS
RIVER BASINS PROJECT
DISTRIBUTION OF COLIEORM BACTERIA
PER 100ml.
CHICAGO HARBOR
OEPT. OF HEALTH, EDUCATION, 8 WELFARE
PUBLIC HEALTH SERVICE
REGION V CHICAGO, ILLINOIS
FIGURE 13
-------
00
"in
«s
CO
00
—(cvi
10
«£
CD
GREAT LAKES 8 ILLINOIS
RIVER BASINS PROJECT
DISTRIBUTION OF COLIFORM BACTERIA
PER 100ml
RACINE HARBOR
00
CVJ
DEPT. OF HEALTH, EDUCATION, 8 WELFARE
PUBLIC HEALTH SERVICE
REGION V CHICAGO, ILLINOIS
FIGURE 14
-------
LEGEND
Coliform Density Per lOOml
100-1,000
1,000-5,000
spoo-iopoo
10,000-40,000
GREAT LAKES 8 ILLINOIS
RIVER BASINS PROJECT
DISTRIBUTION OF COLIFORM BACTERIA
PER 100ml
'MILWAUKEE HARBOR
OEPT. OF HEALTH, EDUCATION, 8 WELFARE
PUBLIC HEALTH SERVICE
REGION V CHICAGO, ILLINOIS
FIGURE 15
-------
"r °
C 10
?> O
^
"in
ro
o
00
^"
"o
o —
C-
ICO
s
A
%
^x—
/-^
^
r
/v
^
™
1^
J^
^==5S^\
^x
/—
s/
/
LEC
fWic<
&2
I/UZ—
SEND
Total Bacterial Densities
Per 100 m 1.
3IPOO-5POO
^ft spoo-iopoo
^ft lopoo-ioopoo
^p loopoo-soopcx
vt
S ^
-J "° CT
-— o — lev) - .-
^«
00 W
o
o
o -I*
I
GREAT LAKES 8 ILLINOIS
RIVER BASINS PROJECT
DISTRIBUTION OF 20°C TOTAL BACTERIA
i PER lOOmt.
CHICAGO HARBOR
DEPT. OF
HEALTH, EDUCATION, 8 WELFARE
0 0 PUBLIC HEALTH SERVICE
°H °- REGION V CHICAGO, ILLINOIS
FIGURE 16
-------
03
N
00
c-
00
Tot a
(O
fe
GREAT LAKES ft ILLINOIS
RIVER BASINS PROJECT
DISTRIBUTION OF 20°C TOTAL BACTERIA
PER 100ml.
RACINE HARBOR
OEPT. OF HEALTH, EDUCATION, a WELFARE
PUBLIC HEALTH SERVICE
REGION V CHICAGO, ILLINOIS
FIGURE 17
-------
LEGEND
Total Bacterial Densities
Per 100 ml.
500-lpOO
ipoo-spoo
spoo-iopoo
lOpOOHOOpOO
IOOpOO-500,000
500.00CHjOOO,000
ijooo,ooo-2poo,ooo
GREAT LAKES 6 ILLINOIS
RIVER BASINS PROJECT
DISTRIBUTION OF 20°C TOTAL BACTERIA
PER lOOmJ.
MILWAUKEE HARBOR
DEPT. OF HEALTH, EDUCATION, 8 WELFARE
PUBLIC HEALTH SERVICE
REGION V CHICAGO, ILLINOIS
FIGURE 18
-------
Evanston
WILSON AVENUE
A
CARTER
O I-
2 O
— UJ
—I -5
-I O
~ tr
(O *
in 2
LU ^
UJ C
tt a:
CC
UJ
gco
^u
§§
o ^
OOD
O cO
LJ
O
3
FOUR-MILE
31st ST
A Water Intake Cribs
4 Beaches
49 th ST.
57*h ST
JACKSON PARK
LJ
a:
LJ
o
z
cc y Q-
z" cc <
O LU O
p w 5
o E
- X
CD
D
Q-
0.
LU
Q
O
(D
LU
tr
PROPOSED DIFFUSOR
r\
FIGURE 19
-------
160
120
> 80
£ 40
0
•
•
i \
:\\
\v
0 4 8 12 16
DAYS
GREAT LAKES a ILLINOIS
RIVER BASINS PROJECT
SURVIVAL OF COLIFORM BACTERIA a
FECAL STREPTOCOCCI IN LAKE MICHIGAN
WATER AT 25°C WITH ILLUMINATION
DEPT. OF HEALTH, EDUCATION, & WELFARE
PUBLIC HEALTH SERVICE
REGION V CHICAGO ILLINOIS
___————————
FIGURE 20
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