United States
Environmental Protection
Agency
Health Effects Research
Laboratory
Research Triangle Park NC 27711
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Research and Development
EPA-600/S1-85-002 Feb. 1985
&ER& Project Summary
Occurrence of Giardia in
Connecticut Water Supplies and
Watershed Animals
Henry Adams and Arthur Bruce
The main objective of this research
was to study the occurrence of Giardia
in selected water supplies and water-
shed animals in Connecticut.
During the period from October,
1979 to October, 1980, water samples
were collected monthly using the U.S.
Environmental Protection Agency
(EPA) Giardia sampling method at
selected water utilities and analyzed for
Giardia cysts. Additionally, samples
were analyzed for total conforms, fecal
coliforms, standard plate count, yeast,
turbidity, and pH.
Fecal specimens were collected from
beaver, deer, squirrel, muskrat. and
racoon if these animals were found on
the watershed. Descriptions of the
watersheds involved in this study in-
cluded size, type, recreation, human
inhabitation, historical water quality
data, known sources of contamination,
efforts to protect watershed, and
species and population estimates of the
watershed animals.
Correlations of the presence of
Giardia cysts with the collected water
quality data were not successful
because no Giardia cysts were detected
on the Giardia sampling filters.
Six out of 413 fecal animal samples
collected on the reservoir watersheds
were found to be positive for Giardia.
Collection of fecal samples from
trapped animals yielded a higher
percentage of Giardia positives than
those collected from live animal
droppings.
Yeast was found more often in raw
water samples than in treated water
samples.
This Project Summary was developed
by EPA -s Health Effects Research Lab-
oratory. Research Triangle Park. NC. to
announce key findings of the research
project that is fully documented in a
separate report of the same title (see
Project Report ordering information at
back}.
Introduction
The purpose of this study was to
determine the presence of Giardia in
selected water supplies and in specific
animals found inhabiting the watersheds
of these water supplies. Four hundred
and thirteen animal fecal samples were
collected and tested for Giardia during
the 12-month study period. One hundred
and forty-four sampling filters were
collected and examined using the EPA
large volume sampling method for
Giardia cysts.
Water quality parameters including
chlorine residual, total coliforms, fecal
coliforms, standard plate count, pH,
temperature, and turbidity were obtained
from samples taken before and after the
Giardia sampling unit was on-line. Yeast
samples were taken after the Giardia
samples were collected. If Giardia was
found on the sampling filters, correlations
with the other water quality parameters
would be determined.
Background
Very little information is known about
the presence of Giardia in water supplies
or in watershed animals in Connecticut.
Similar studies to this one have been
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conducted in the State of Washington
where Giardia was found to be a common
intestinal parasite of beaver and muskrat.
The presence of Giardia would indicate a
potential health hazard to the consumers
of unfiltered surface water supplies in
Connecticut and show Giardia to be
potentially a widespread problem in
public water supplies. Numerous
outbreaks have been documented impli-
cating Giardia in drinking water in such
places as Rome, New York; Camas,
Washington; and Aspen, Colorado, as
well as others.
Methods
This study consisted of two methods to
evaluate the presence of Giardia in
certain water supplies and the
watersheds of these water supplies.
One method used EPA large volume
samplers for collecting Giardia cysts.
Once a month the selected sites were
sampled, with the sampling device on-
line for approximately 24 hours. Total
coliform, fecal coliform, standard plate
count, turbidity, and pH samples were
collected for analysis prior to and after the
large volume sampler was on-line. Yeast
samples were taken after the large
volume sampler was on-line. Total
chlorine and free chlorine residual were
measured at each site prior to and after
the filtering unit was installed. The EPA
large volume samples were used on both
the raw water tap and the treated water
tap if the treatment of the water supply
included filtration. Where the water
supply treatment did not include filtra-
tion, samples were taken only from the
treated water tap.
The presence of Giardia in fecal speci-
mens from watershed animals that
included beaver, deer, squirrel, muskrat,
and racoon was determined for those
animals found on each watershed. The
animal fecal samples were collected by
members of the trappers association. The
collected fecal samples were^ placed in
formalin containing vials and later
analyzed for Giardia. The trappers
collected from all the different species of
animals so that one species would not
account for all the samples to the exclu-
sion of another species more difficult to
sample. However, because some animals
were not present on the watersheds at
the time of collection, all the different
animal species were not sampled every
month. A maximum of 10 samples per
month for each selected watershed was
permitted. The fecal specimens were
collected by one of two methods. Animals
were trapped using the leg-hold trap
during the trapping season when
permission was granted by the land
owner. After trapping season, all fecal
samples were collected from animal
droppings. Trappers collecting the fecal
droppings from live animals were
requested to collect samples from
different locations and to take only one
sample per animal. This, hopefully, would
lessen the possibility of sampling an
animal more than once.
Initially, the fecal samples were to be
collected by only one method, live-
trapping of the animals. This method was
found to be more expensive than using
the leg-hold trap because the trappers
would have to purchase the "live-type"
traps. This type of trap required more
room when transporting between
trapping locations. A method of marking
the animals would be necessary when
using the live-trapping method to prevent
sampling from the same animal more
than once.
Comparisons and correlations were
made between the different collection
methods of obtaining the animal fecal
specimens, the site locations, and the
physical and bacteriological-test data
with the presence of Giardia.
Laboratory Methods
The EPA large volume sampling filters
were analyzed according to EPA method-
ology. The animal fecal samples were
processed using the formalin-ether sedi-
mentation concentration technique, then
examined microscopically. The enumera-
tion and isolations of yeast were based on
APHA Standard Methods for the Exami-
nation of Water and Waste Water. The
bacterial analysis, turbidity, color, odor,
and pH determinations were also per-
formed according to Standard Methods
for the Examination of Water and Waste
Water by the Laboratory Division of the
Connecticut State Department of Health
Services. The temperature and chlorine
residual were determined at each site.
The total and free chlorine residual were
determined by DPD colorimetric method.
The sites that were sampled for Giardia
were selected in two ways: (1) areas with
low and high stool positivity rates for
Giardia. and (2) watershed with no known
human activity (protected) and with
human activity and/or human sources of
sewage contamination (semi-protected).
G/artf/a-positive stool sample data
provided by the State Department of
Health were used to calculate human
stool positivity rates for each town in
Connecticut. Rates varied from .03 per
1,000 to 1.94 per 1,000. Two towns with
low Giardia positivity rates were selected
and matched with two towns with high
Giardia positivity rates based on
population density and population served
by a community water supply. The project
director selected additional sites based
on criterion No. 2. One source that had
been selected was changed because it
had not been used as a water supply for
several years.
Results
A total of 413 fecal specimens were
submitted to the laboratory for Giardia
determination over the consecutive 12-
month study period from November,
1979 through October, 1980. Only six
samples (1.4%) were found to be positive
for Giardia. Fecal samples submitted
during trapping from November, 1979
through February, 1980 were 2.34%
positive for Giardia. Fecal samples
collected after trapping season were
1.1% positive.
During the fecal specimen examina-
tion for Giardia cysts, other parasites
were found. The beaver specimens,
mainly from one watershed, had the
lowest percentage of parasites found of
the animal types studied with 16.7%. The
racoons studied were found to have the
most parasites of the animals examined
with 64.8% of the specimens giving a
positive result. Most of the other para-
sites found were helminths.
A total of 144 water sampling filters
were collected for Giardia analysis using
the EPA large volume sampling method.
All of these filters were determined to be
negative for the presence of Giardia. A
total of 288 water samples were
submitted for bacteriological analysis. Of
the three types of bacteriological
analyses used, total coliform, fecal
coliform, and standard plate count, bac-
teria were found in the majority of the raw
water samples. Bacteria were not present
in most of the treated water samples.
A total of 74 samples were tested for
the presence of yeast. Thirty samples
were from raw water sources and 44
were from treated water sources. Yeast
wasfound in 12ofthe raw water samples
and in 3 of the treated water samples.
Conclusions
1. Giardia cysts were not recovered
from any of the 144 Giardia
sampling filters examined.
2. Only six, four muskrat (Ondatra
zibethicus) and two racoon (Procyon
lotor), of 413 animal fecal specimens
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examined were found to be positive
for Giardia.
3. Animal fecal specimens collected
from the leg-hold trapped animals
showed a slightly higher percent
positivity for Giardia than speci-
mens collected from the live animal
droppings.
4. The racoon fecal specimens were
found to have the most parasites of
the animal types examined. The
beaver specimen had the lowest
percentage of total parasites found.
5. Coliform bacteria and yeast were
found frequently in raw water
samples and less frequently in
treated water samples.
6. The bacteriological water quality
data collected during the month that
Giardia positives were found in
animal fecal samples showed no
relationship to the presence of
Giardia in animal fecal samples.
7. If the areas selected are representa-
tive of Connecticut water supplies
and watersheds, then Giardia was
not prevalent in Connecticut water
supplies during the period of the
study.
Recommendations
Since the recovery rate for cysts is
generally known to be below 10% for the
EPA sampling method, it cannot be stated
that Giardia does not exist in Connecticut
water supplies. Gross contamination of
the water supplies by Giardia appears
unlikely in those areas sampled. The
presence of Giardia in water supplies can
be more accurately determined if the
recovery rate for this method improves
significantly.
Additional collection of animal fecal
specimens using the leg-hold trapping
method would be the best method for
determining the presence of Giardia in
watershed animals, and thus, the
potential for contamination of water
supplies.
Further testing of yeast in water
supplies might be useful in determining
its possible relationship to Giardia.
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Henry Adams and Arthur Bruce are with State Department of Health Services.
Hartford. CT 06115).
Jheadere H. Ericksen is the EPA Project Officer (see below).
The complete report, entitled "Occurrence of Giardia in Connecticut Water
Supplies and Watershed Animals," (Order No. PB 85-151 199/AS; Cost:
$10.00, subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Health Effects Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC27711
* U.S. GOVERNMENT PRINTING OFFICE; 1986 - 569-016/7908
United States
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