xvEPA
United States
Environmental Protection
Agency
Health Effects Research
Laboratory
Cincinnati OH 45268
Research and Development
EPA-600/S1-81-030 May 1981
Project Summary
Evaluation of the Health Risks
Associated with the Treatment
and Disposal of Municipal
Wastewater and Sludge
C. S. Clark, H S Bjornson, J. W Holland, V. J. Elia, V A Majeti, C. R. Meyer,
W. F. Balistreri, G. L. Van Meer, P. S. Gartside, B. L. Specker, C. C.
Lmnemann, Jr., R. Jaffa, P. V. Scarpino, K. Brenner, W. J. Davis-Hoover,
G. W. Barrett, T. S. Anderson, and D. L. Alexander
Since 1975 a major research pro-
gram has been underway at the Uni-
versity of Cincinnati to determine
some of the potential human health
risks associated with the collection,
treatment and land disposal of munic-
ipal wastes. The first phase of this
effort focused on occupational expo-
sure to viruses and bacteria associated
with sewer maintenance and conven-
tional activated sludge wastewater
treatment. The second phase of this
effort, starting in 1977, included
study of exposure to different agents:
organic chemicals, fungi and endo-
toxins; and different processes: com-
posting of wastewater plant sludges,
hazardous waste disposal, the spray
irrigation of wastewater, and the land
application of sludge. The various
projects carried out during the second
phase of the program are described in
this report.
A study of workers involved in
composting of wastewater treatment
plant sludge by the aerated pile method
was initiated to evaluate the potential
health effects of exposure toAspergil-
lus fumigatus and other viable and
nonviable components of sludge in
Camden, N.J., Washington, D.C. and
Beltsville, MD. The study consisted of
clinical and serologic evaluation of
workers four times a year, physical
examinations, and environmental mon-
itoring.
A health study was conducted of the
residents of a small community in
Hardeman County, Tennessee, who
were exposed to carbon tetrachloride
and other toxic chemicals in their
drinking water as a result of contami-
nation of their domestic wells by a
nearby hazardous waste dump. The
study consisted of analysis of blood
specimens for liver and kidney function
parameters, determination of serum
and urine bile acid concentrations,
physical examinations, interviews and
air and water monitoring.
Workers exposed to chlorinated in-
secticide substances discharged to
the sewer by a pesticide formulator
were studied at the North Wastewater
Treatment Plant, Memphis, Tennessee.
The study was undertaken to determine
if evidence of exposure to hexachloro-
cyclopentadiene (HEX), hexachlorobi-
cycloheptadiene (HEX-BCH), hepta-
chlorobicycloheptene, and chlordene
could be detected by analysis of urine
specimens from the workers.
In order to assess the potential for
health risks associated with the spray
irrigation of wastewater, a clinical and
virus serologic evaluation of workers
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and wastewater and air monitoring for
viruses, pathogenic bacteria, and vol-
atile organic chemicals was conducted
in Muskegon County, Michigan.
A field ecosystem study was carried
out at Miami University, Oxford, OH,
to evaluate the effects of land applica-
tion of heat dried municipal waste-
water treatment plant sludge (Milor-
ganite) on vegetation, insects and
meadow voles.
Reports have been prepared from an
evaluation of pertinent literature on
potential health effects from viable
and nonviable emissions (EPA-600/1 -
81 -006) and persistent organics (EPA-
600/1 -80-025) associated with waste-
water treatment plants and land appli-
cation sites. The potential health effects
associated with sludge incineration
and pyrolysis are presented in this
report.
This Project Summary was devel-
oped by EPA's Health Effects Research
Laboratory, Cincinnati, OH, to an-
nounce 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
Contact with wastewater, wastewater
sludge, and waters receiving such
discharges have long been regarded as
a public health risk. Assumptions con-
cerning these risks have served as a
basis for the promulgation of standards
for recreational waterqualityand for the
construction and operation of facilities
for wastewater and wastewater sludge
treatment. However, there is a paucity
of documented evidence concerning the
nature and extent of the risks involved.
The increased pace of construction of
new wastewater and sludge treatment
facilities in recent years, the improve-
ment of existing facilities and the em-
phasis on the land application of the
residuals produced, lend impetus to the
need to evaluate the risks involved. One
approach is to investigate the health
conditions of individuals engaged in
wastewater and wastewater sludge
treatment and disposal activities. Among
the other approaches are the examina-
tions of populations exposed through
contamination of drinking water sup-
plies and the investigation of the effects
of sludge applications on the vegetation,
insects and mammals in semi-enclosed
grassland ecosystems. Each of these
approaches was utilized in one or more
of the investigations included in this
project.
Sewage Sludge Compost
Worker Study
Sewage sludge composting by the
windrow method has been practiced for
a number of years by the Los Angeles
County Sanitation District. More recently
the development of the aerated pile
composting method by the U.S. Depart-
ment of Agriculture, Agricultural Re-
search Station at Beltsville, MD, has
resulted in considerable expansion of
the use of sludge composting. Currently,
Philadelphia, PA, Camden, N.J., Wash-
ington, D.C., Windsor, Ontario, Bangor
and Portland, ME, as well as other cities
are engaged in municipal sludge com-
posting. Many other cities are actively
considering this method. A number of
factors are apparently responsible for
the expansion in the use of sludge
composting. Among them are the prohi-
bition of ocean dumping of sludge after
1981, the increase in the amount of
sludge being produced nationally and
the growing emphasis on the land
application of wastewater and waste-
water sludges. Composting is a thermo-
philic process and the heat generated
helps inactivate the microorganisms
present in sludge. However, the heat
generated during composting also en-
courages proliferation of thermophilic
fungi, in particular,Aspergillus fumigatus,
and actinomycetes. Aspergillus fumi-
gatus. an opportunistic pathogen, is one
of the most prevalent fungi during the
sludge composting process. Because
they are heat resistant, bacterial endo-
toxins are also present in composted
sludge. A prospective health study was
initiated in 1979 to determine if workers
at municipal sludge composting facilities
are subjected loan increased health risk
from exposure to viable fungal particles,
actinomycetes, and endotoxins in addi-
tion to the pathogenic microorganisms
that are normally present in municipal
wastewater and sludge. The clinical and
serologic evaluation of workers exposed
to dust at the composting site included:
1) comprehensive history and physical
examination; 2) health questionnaires;
3) illness monitoring; 4) liver and kidney
function profiles; 5) anterior nares and
oropharyngeal swab cultures; 6) chest
X-ray; 7) complete blood count with
differential; 8) determination of anti-
bodies directed against A. fumigatus; 9)
determination of antibodies directed
against lipopolysaccharide (LPS) present
in compost samples; 10) skin testin
with A. fumigatus antigen; 11)pul--
monary function tests; 12) quantitation
of total IgG, IgM, IgA, and IgE; and 13)
determination of C-reactive protein,
levels of C3 and CH5o. Health question-
naires, anterior nares and oropharyngeal
swab cultures and sera for each of the
serologic tests were obtained five times
during 1979, the first year of the in-
vestigation. Statistical comparisons
among the groups were made by means
of the chi-square, Fisher's Exact and
Mann-Whitney one-tailed ranking tests.
Environmental monitoring for fungi and
bacteria using six-stage Andersen sam-
pler was also conducted several times
during the first year.
Pesticide Waste Dump Health
Study
Improper disposal of hazardous chem-
ical waste is increasingly being recog-
nized as a source of a potential human
health hazard. A health study of the
residents of a small community in
Hardeman County, TN, exposed to toxic
chemicals in drinking water as a result
of contamination of their domestic wells
was initiated in 1978. The residents
were exposed to carbon tetrachloridej
(CCU) and other chlorinated organil
contaminants from their private wate™
supply wells and possibly in ambient air^
The source of these contaminants i
groundwater was probably from leachates
from a chemical waste landfill formerly
used by a Memphis, TN, pesticide for-
mulator which manufactured chlorinated
insecticides. A study to determine if the
residents showed any detectable health
effects from exposure to toxic organic
chemicals in their drinking water was
conducted during the Fall and Winter of
1978-1979. The protocol included the
analysis of blood specimens for several
parameters of liver and kidney function;
determination of concentrations of the
bile acids, sulfated conjugates of litho-
cholate (SLCC), and cholyglycine (CG) in
urine and serum samples; physical
examinations; health questionnaires
and air and water monitoring. The data
were checked for normality and trans-
formed where necessary. Statistical
comparisons among the groups were
made using analysis of covariance and
with contingency tables. Air samples
were collected on chromosorb 102
Analyses of air, water and urine samples
for organic chemicals were performes
by electron capture gas chromatography
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Exposure to Pesticide
Chemicals at a Wastewater
Treatment Plant
During a prospective seroepidemio-
logical study of the bacterial and viral
disease risks associated with municipal
wastewater treatment, an opportunity
developed to investigate exposure to
toxic organic chemicals emitted from
the wastewater during the treatment
process at one of the plants in the study.
Workers at this plant, the Memphis
North Wastewater Treatment Plant, had
been complaining in early 1978 of acute
symptoms of respiratory distress that
they associated with periods of intense
chemical odor at the plant. Other symp-
toms noted were dizziness, headache,
and irritation of the eyes, nose, throat,
lungs and skin. The treatment plant is
located near a manufacturer that pro-
duces and utilizes several chlorinated
organic intermediates for the formula-
tion of flame retardants and chlorinated
insecticides (notably isodrm, endrm,
chlordane and heptachlor). Chemical
waste from this manufacturer is dis-
charged into a sewer that flows to the
Memphis North Wastewater Treatment
Plant. During 1978 exposure to several
chlorinated organic compounds including
HEX and HEX- BCH at this treatment
plant was assessed by evaluating urinary
excretion, illness symptoms and air and
wastewater contamination. Chemical
analyses were performed by electron
capture gas chromatography. The data
were checked for normality and trans-
formed where necessary. Statistical
comparisons among the groups were
made using analysis of covariance.
Exposure of Wastewater Spray
Irrigation System Workers to
Viruses, Bacteria and Organic
Chemicals
As a result of legislative actions, such
as the 1972 Clean Water Act and its
1977 Amendments, land application of
municipal wastewater and sludge after
pretreatment is becoming increasingly
popular as an alternative means to the
more conventionally used disposal
methods, such as ocean and surface
water dumping, and incineration. Spray
or sprinkler application is one of the
commonly used methods of land ap-
plication of wastewater. The volatile
organic chemicals and microorganisms
present in wastewater may become
airborne during spray application and
are a potential risk to the workers
involved with the operation of the
facility. In order to assess the potential
health risks of workers from exposure to
volatile organic chemicals and viruses
in aerosols, the ambient air environ-
ment and the workers at the Muskegon
County Wastewater Management Sys-
tem, Ml, were evaluated. Air samples
for animal virus and coliphage assay
were collected with an Army prototype
XM2 Biological Sampler/Collector. Air
sample filtrates were inoculated into
BGM cells derived from primary African
green monkey kidney cells. Coliphage
assay of air and water samples was by
the soft agar overlay method. Six-stage
viable particle Andersen samplers were
used for the collection of air samples for
the determination of total bacteria, total
and fecal coliforms and for the identi-
fication of gram-negative and gram-
positive bacteria. The concentration of
chloroform, carbon tetrachloride, tri-
chloroethane, trichloroethylene and
tetrachloroethylene in air samples
collected on chromosorb 102 and char-
coal tubes and in water samples were
determined by use of electron capture
gas chromatography. Blood samples,
throat and rectal swabs and illness
symptom data were collected on a
monthly basis from June through Octo-
ber. Antibodies to poliovirus types 1, 2
and 3, coxsackievirus types B2 and B5
and echovirus types 7 and 11 were
determined using a microneutralization
technique. Comparisons between the
groups for the virus serology results
were accomplished by contingency
tables and chi-square analyses. Viral
cultures from throat and rectal swabs
were inoculated into cell cultures of
African green monkey kidney, vero
monkey kidney and WI-38. Viruses,
including those recovered from waste-
water, were identified by neutralization
with Lim-Benyesh-Melnick antisera
pools.
Effects of Wastewater
Treatment Plant Sludge on
Two Grassland Ecosystems
A field ecosystem study was carried
out at Miami University, Oxford, OH, to
evaluate the effects over a two-year
period of land application of heat dried
municipal sludge (Milorganite) on vege-
tation, insects and meadow voles in
sixteen one quarter acre semi-enclosed
plots. Eight of the plots were initially in
the fourth year of grassland succession
(perennial field) and eight had previously
been sowed to winter wheat (annual
field). Six of the plots received surface
application of Milorganite monthly for
five months during the growing season,
six received a commercial fertilizer
containing equivalent amounts of nitrogen-
phosphorus and potassium and four
were controls. Five breeding pairs of the
meadow vole Microtus pennsylvanicus
were placed inside each enclosure in
the Spring of each year.
The study focused on three aspects of
the grassland ecosystems which maybe
affected by sludge deposition: structure
and energetics of the total ecosystems,
population dynamics of small mammals,
and population dynamics of arthropods.
Comparison between control and exper-
imental plots in each grassland type
provided information regarding the
effects of sludge on the ecosystem as a
whole. Comparison of the experimental
plots between the two grassland types
provided information as to which eco-
system is better able to process sludge
most efficiently. The effects of sludge on
vegetative community structure was
considered by comparison of species
diversity between control and exper-
imental plots. Productivity was mea-
sured by the short-term harvest method.
Diversity was determined by the number
of species per 0.25 m~2, Margalef's
richness index, Shannon-Weaver's
function, and Pielou's evenness index.
Vole population dynamics in the control
and experimental systems were compared
on the basis of age structure, turn-over
rate, population growth rate, and carry-
ing capacity. Vole population densities
were related to vegetation nutrient
content in a test of Pitelka and Shultz
theories of nutrient-recovery and nutri-
ent cycling effects Arthropod response
to treatment was evaluated for all major
orders in terms of density and biomass.
One order (Homoptera) was analyzed in
detail regarding species richness and
apportionment. During November of
each year the voles were sacrificed for a
complete autopsy and for histopathology
of liver, lungs, kidney and testes or
ovaries. These organs were also analyzed
for cadmium, lead, copper and zinc
content.
Potential Health Effects From
Viable and Nonviable Emissions
Associated With Sludge Incin-
eration and Pyrolysis
A literature review of chemical, bio-
logical, and environmental literature
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was initiated in 1978 to evaluate the
potential health effects of emissions
from wastewater and sludge treatment
operations including land application
from agents such as viruses, pathogenic
microorganisms, toxins and persistent
organics. Individual reports have been
prepared from the literature evaluation
on viable and nonviable emissions
(EPA-600/1 -81 -006) and persistent
organics (EPA-600/1-80-025). Poten-
tial health effects of incineration and
pyrolysis of sludge are discussed in this
report.
Conclusions
Some of the conclusions of the various
investigations involved in this project
are as follows.
Sewage Sludge Compost
Workers Study
1. Results of the environmental
monitoring demonstrated that
workers at each of the compost
sites were exposed to markedly
elevated numbers of A. fumigatus
spores. This observation was
further supported by the compar-
atively high frequency of isolation
of A. fumigatus from oropharyn-
geal and anterior nares cultures
of compost workers when com-
pared to the intermediate-exposed
and control groups.
2. Preliminary analyses of the high-
est results obtained for each
participant on tests for the enzymes
serum glutamic oxaloacetic trans-
aminase (SCOT), serum glutamic
pyruvic transaminase (SGPT),
measures of liver function; abso-
lute eosinophil count; total IgG,
IgE, and IgM antibodies; and
specific IgG antibody directed
towards A. fumigatus, determined
by the enzyme-linked immuno-
sorbent assay, did not reveal any
differences among exposure groups
at any of the sites.
3. The only significant difference in
an examination of C-reactive
protein (CRP) was found among
Beltsville workers. Four of nine
compost workers had positive
CRP values compared to none of
eight intermediate-exposed
workers.
4. Levels of antibody directed against
lipopolysaccharide (LPS) prepared
from site-specific compost as
determined by the enzyme-linked
immunosorbent assay were not
found to be higher among Camden
compost workers than in control
workers. However, in Beltsville
and Blue Plains antibody liters
among compost workers were
higher than in their correspond-
ing lower exposure groups.
5. One worker in the study, em-
ployed at a compost site, was
found to have a local infection
involving his right ear. This in-
fection caused by/4, niger grad-
ually progressed over a period of
several months. Despite treat-
ment, there was erosion of 70%
of the right tympanic membrane.
6. Chest X-rays were obtained from
74 participants and reviewed by a
radiologist at the University of
Cincinnati. Of these, one compost
worker's X-ray exhibited an ab-
normality compatible with an
occupationally-related disorder.
Pesticide Waste Dump Health
Study
7. Concentrations of CCU in the
contaminated wells were of the
order of 5000 A/g/L. Assuming a
consumption of one liter per day,
the individuals using thecontam-
inated water had a dose of about
5 mg/day, CCU.
8. Results from the initial screening
in November 1978 after almost
all potable use of the contami-
nated water had ceased, revealed
that the concentrations of the
serum enzymes alkaline phos-
phatase, SGPT and SGOT were
elevated in the group of residents
who had previously consumed
the contaminated water when
compared to the control group.
The differences appear to be
associated with the ingestion of
well water contaminated by.leach-
ate from a toxic waste landfill.
Two months later many of the
persons with abnormal test results
had results in the normal range.
9. During the January 1979 survey,
six individuals from the exposed
group and one from the interme-
diate-exposed were found to have
enlarged livers.
10. The mean nonfasting serum bile
acid, sulfated conjugates of SLCC,
was significantly lower in the
exposed group than in the con-
trol.
11. For those persons in the exposec
group who were tested in both
November 1978 and January
1979 nonfasting serum concen-
trations of SLCC and CG were
significantly higher in November
1978 than in January 1979.
12. The potential long-term health
effects of exposure to these chem-
icals in drinking water is not
known.
Exposure to Pesticide Chemicals
at a Wastewater Treatment
Plant
13. Influent wastewater from the
North Plant, and air samples
collected at the wet well and grit
chamber of the North Plant in
Memphis, TN, contained several
contaminants including HEX,
HEX-BCH, heptachlorobicyclo-
heptene and chlordene.
14. Influent wastewater and air sam-
ples obtained at the grit chamber
of the Maxson Plant, the control
plant in Memphis, TN, did not
contain the type of substances
found in the samples obtained at
the North Plant.
15. Urinary excretion of HEX-BCH
was found to increase during the
work shift for workers at the
North (exposed) plant in the June
1978 survey, whereas it de-4
creased during the work shift at™
the Maxson (control) plant. The
percent of exposed plant urine
samples with HEX-BCH concen-
trations greater than 3/L/g/L in-
creased from 7 to 41 during the
work shift while in control plant
samples the percent decreased
from 9 to 0, during the June 1978
screening.
16. The significance of the presence
of these chlorinated organic
chemicals in the urine of workers
and the potential long-term health
effects of exposure to these chem-
icals is not known.
Exposure of Wastewater Spray
irrigation System Workers to
Viruses, Bacteria and Organic
Chemicals
17. No animal viruses were detected
in air samples collected at the
Muskegon County Wastewater
Management System using the
Army prototype XM2 Biological)
Sampler/Collector.
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18. Animal viruses were detected in
raw influent samples but de-
creased in concentrations as the
wastewater was aerated and
stored in the lagoons. None were
detected in wastewater at the
pump station just prior to distri-
bution to the spray irrigation rigs.
19. Using the centrifugation-filtration
method all raw influent samples
were found to contain viruses,
ranging from 50 to 400 plaque-
forming units/liter.
20. Coliphage were removed from air
samples at the aeration basins in
concentrations ranging from 0-9
per cubic meter of air. E. coli
13706 coliphage was recovered
more often than the other two
tested, 15597 and 11303.
21. Illness and virus isolation rates
were not significantly different in
the study group of workers en-
gaged in the spray irrigation of
wastewater compared to a control
group of road commission workers.
22. Antibody titers to coxsackievirus
B5 were significantly higher for
one subgroup of wastewater
workers, the spray irrigation noz-
zle cleaners, when compared to
either other wastewater workers
or to the road commission work-
ers. This suggests that there may
be a risk of viral infection only in
those with the greatest and most
direct exposure to wastewater.
23. The prevalence of Hepatitis A
antibody correlated with age, as
would be expected in normal
populations, and there was no
increase in the prevalence of
Hepatitis A antibody in those
exposed to spray irrigation.
24. Antibody titers to poliovirus 1, 2
and 3, coxsackievirus B2 and
echovirus 7 and 11 were not dif-
ferent between the wastewater
and road commission worker
groups.
25. The quantity of bacteria in the air
downwind of treatment sources
at the Muskegon wastewater site
contained higher total numbers
of bacteria and higher percent-
ages of gram-negative bacilli,
fecal-indicator bacteria, and
pathogenic bacteria than upwind
air.
26. The mean respirable concentra-
tion of the total airborne bacteria
found one meter downwind of
the aeration basin at the Muskegon
wastewater site was 2800 Colony
Forming Units (CPU) per m3
which was significantly higher
than that found 1 8 meters down-
wind of the spray irrigation rigs
(i.e., 700 CPU per m3). Concentra-
tions one meter upwind of the
aeration basin and 18 meters
upwind of the field rigs were 490
CFU/m3 and 660 CFU/m3, re-
spectively.
27. Relatively high airborne levels of
respirable Klebsiella spp. were
found downwind of wastewater
operation compared to most other
recent studies.
28. Concentrations of tnchloroethane,
trichloroethylene and tetrachloro-
ethylene at the Muskegon County
Spray Irrigation System at the
downwind edge of the aeration
basins ranged up to 90 ng/L, 73
fjg/L and 46 /t/g/L, respectively.
Adjacent to the spray irrigation
rigs the highest concentrations
reached for the same compounds
were 2.7, 9.3 and 8.6, respec-
tively. All of these concentrations
were well below the 8-hour oc-
cupational standards of 45,000
//g/L, 535,000 A/g/L and 670,000
L, respectively.
29. Chloroform was not detected in
the air adjacent to the spray
irrigation rigs but was detected
downwind of the aeration basins
at concentrations ranging up to
202 fjg/m3 (8-hour occupational
limit 50,000 A
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Potential Health Effects From
Viable and Nenviable
Emissions Associated With
Sludge Incineration and
Pyrolysis
39. A literature evaluation indicated
that incineration and pyrolysis
processes may lead to air pollu-
tion from volatilization of heavy
metals and incomplete combus-
tion of organic chemicals, respec-
tively. The air pollution can be
controlled by the use of appro-
priate control measures in both
incineration and pyrolysis processes
and also by afterburning in the
case of pyrolysis.
Recommendations
1. Compost workers should be ob-
served over an extended period of
time to reveal abnormalities which
may be related to the length of
exposure.
2. The preliminary data on antibody
response of the compost workers
to lipopolysaccharide prepared
from compost samples suggests
that it may be advisible to take
precautions to reduce exposure,
such as the use of respirators by
compost workers and periodic
water spraying of the compost
sites to reduce dust.
3. A method should be developed to
quantify the presence of endo-
toxin in compost and in the air.
4. Long-term medical follow-up of
the residents of Toone-Teague
Road, Hardeman County, TN,
should be initiated.
5. Necessary precautions should be
taken, if possible, to prevent the
contamination by these toxic
chlorinated organic chemicals of
the artesian aquifer below the
Hardeman County dump site,
since it is used as a water supply
for the City of Memphis.
6. The closure plan for this dump
site should be designed to prevent
an increased exposure to nearby
residents and to those downstream
and downwind to contaminants
associated with the dump.
7. Industrial discharge of toxic chemi-
cal waste into municipal sewerage
systems should be controlled and
monitored.
8. A follow-up study of the workers
involved at the Memphis North
Treatment Plant should be con-
ducted to determine if urinary
excretion of HEX and HEX-BCH
remains at the low levels
detected in September 1978 and
if any health effects are apparent.
9. The XM2 Biological Sampler/
Collector should be used for a
sampling period of at least sever-
al days to determine if animal vi-
ruses can be detected in aerosols
sampled by this method at the
Muskegon, Ml spray irrigation
site.
10. The virus content of solid material
at the bottom of the lagoons and
aeration basins at the Muskegon,
Ml spray irrigation site should be
determined to see if future disposal
of the solid material would be a
problem.
11. The Kott's MPN method is recom-
mended for use when coliphage
levels are expected to be very
low.
12. Because of problems with the
XM2 sampler and sterilization
and arcing problems in other
large volume samplers, an im-
proved large volume biological
air sampler should be developed.
13. Resistant aerosolized bacteria
such as Klebsiella should be
explored as possible indicators of
bacterial air contamination from
fecal sources.
14. An examination of the serum of
workers at the Muskegon spray
irrigation site for antibodies to
Klebsiella should be initiated.
15. Routine air monitoring for selected
organic compounds should be
performed downwind of the aera-
ration basins and in the scrubber
house at the Muskegon spray
irrigation site.
16. The observation of an apparent
increased risk in nozzle cleaners
at Muskegon should be confirmed.
The number of available nozzle
cleaners is small, but a serologic
survey of former nozzle cleaners
could be conducted.
17. The hypothesis that wastewater
workers may be at risk of Legion-
narie's disease could be evaluated
further by testing for antibody to
Legionella pneumophila which
has been related to blue green
algae. Wastewater irrigation work-
ers may be exposed to wastewater
with higher algae content than
ordinary wastewater treatment
plant workers.
18. For minimizing effects on smal
mammal populations mid-suc-
cessional old-fields should be
used as sites for the land application
of sludge, rather than early suc-
cesessional stages or agricultural
fields.
19. Research should continue to
more completely characterize the
effect of sewage sludge application
on mammal populations, especially
to evaluate if Cd concentrations
tend to increase in the kidneys
and livers of animals functioning
within sludge-treated plant com-
munities.
20. Afterburning should be used in
the pyrolysis process to assure
complete combustion of organic
chemicals in sludge.
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4
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C. S Clark. H. S. Bjorson. J. W. Ho/land, V. J Elia, V. A. Majeti, C. R. Meyer.
W. F. Balistreri, G. L Van Meer. P. S. Gartside, B. L Speaker, C. C. Linnemann.
Jr., R. Jaffa, P. V. Scarpino, K. Brenner, W J. Davis-Hoover, and D. L.
Alexander are with the University of Cincinnati, Cincinnati, OH 45267, G. W.
Barrett and T. S. Anderson are with Miami University, Oxford, OH 45056.
Herbert R. Pahren is the EPA Project Officer (see below).
The complete report, entitled "Evaluation of the Health Risks Associated with
the Treatment and Disposal of Municipal Wastewater andSludge, "(Order No.
PB 81-175 945; Cosf $20.00, subject to change} will be available only from.
National Technical Information Service
5285 Port Royal Road
Springfield, V'A 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Health Effects Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
5 US GOVERNMENT PRINTINOOFFICE' 1961 -757-012/1186
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United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
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Fees Paid
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Protection
Agency
EPA 335
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Penalty for Private Use S300
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