xvEPA
United States
Environmental Protection
Agency
Health Effects Research
Laboratory
Cincinnati OH 45268
Research and Development
EPA-600/S1-81-026 Apr. 1981
Project Summary
Sewage Sludge Viral and
Pathogenic Agents in
Soil-Plant-Animal Systems
G. T. Edds and J. M. Davidson
In this study, a multi-disciplinary
approach was used to determine the
ultimate fate of various toxic elements
or pathogens associated with Florida
and Chicago municipal sludges when
applied to soil-plant-water systems as
an alternative method for the utiliza-
tion of recycled digested municipal
sludges. Determination was made of
the physiologic, pathologic, growth,
and reproductive responses of cattle,
swine, and poultry that were fed
sludges, grains, or forages from soils
pretreated with urban liquid digested
sludges, as well as health effects in
mice receiving liver or kidney tissues
from steers and swine exposed to such
feeds or contaminants.
There were minimal differences in
growth performance or egg produc-
tion in cattle, swine, or poultry fed
forage or grain from soils pretreated
with a variety of urban sewage
sludges. Cattle and swine tissues,
when fed to mice, resulted in altera-
tions of the normal mineral balance as
well as reproductive performance.
Tissues from animals intended for
human consumption exposed to
sarcocyst contaminated sewage
sludges may serve as health hazards
for animals and humans.
Application of urban sludges at 19.8
ton/hectare produced equivalent
plant growth stimulation for corn,
barley, wheat, and sorghum as com-
mercial fertilizers. Certain bacteria,
commonly associated with sludges,
disappear in a few days after soil or
plant application. However, certain
viruses and parasites were shown to
persist. New and improved methods
were developed to monitor persis-
tence as well as assay for the presence
of drugs or other hazardous materials.
This Project Summary was develop-
ed 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).
Discussion
This research was initiated to deter-
mine if digested sewage sludges could
be applied to a soil-plant-ammal system
to improve soil fertility, increase forage
and grain production, and provide
animal feeds necessary for optimal
animal growth or performance without
posing a hazard to plant and animal
production or human health. The
studies also included the persistence
and movement of pathogens, drugs, or
chemicals in soils, plant products, or
animal tissues
Beef steers were fed digested munici-
pal sludges incorporated into feedlot
diets and feeds (corn grain, forage,
sorghum silages, and bahia-grass
pastures) produced on land treated with
sludge. These studies were conducted
to determine the effects of these feeding
programs on animal performance,
carcass quality, and concentrations of
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selected toxic elements in liver, muscle,
and kidney tissues The performance
and carcass data of treated steers m all
of the studies were generally not dif-
ferent from the control steers.
The effect of feeding sewage sludge
on reproductive performance in female
swine during successive gestation-
lactation periods was evaluated. These
studies indicate that breeding, farrow-
ing, and rebreedmg weight were
reduced. Lactation and gestation weight
changes were lower and fewer pigs
were farrowed m sow groups fed 10 to
20 percent sewage sludge in theirdiets.
Duplicate experiments of 21 days
duration were conducted with day-old
broiler-type chicks and laying hens to
study the influence of replacing one-
half of all the normal dietary corn
complement with corn growth on soil
fertilized with municipal sludge. Corn
from the sludge-amended soil did not
adversely affect final body weights or
daily feed intake Substitution of a
sludge with high metal concentrations
or equivalent levels of certain hazard-
ous metals altered growth and laying
performance.
Toxicity from feeding dried sewage,
included in a normal swine starter
ration, may occur from a deficiency of
available protein or other essential
nutrients, or from the accumulation of
hazardous chemical residues Cadmium
exposure induced microcytic and hypo-
chromic anemia. Cadmium also induced
differences in the activity of liver serum
enzymes in pigs exposed to aflatoxin 61
or warfarin This is the first demonstra-
tion of the cadmium blocking effect on
the microsomal enzyme system in pigs.
Of seven pigsfed 10 percent Gainesville
sludge, four had Sarcosporidia in the
myocardium, and the hearts of two of
four pigs fed 20 percent contained the
parasite. Among cattle fed Pensacola
sludge, 19 of 32 contained Sarcospor-
idia in the cardiac muscle, while cardiac
muscle of six of 17 controls were parasi-
tized. The presence of Sarcosporidia in
hearts of swine and cattle fed sludge
may be of public health significance.
Land spreading of sewage sludge is
probably the most practical means of
disposal for municipalities and cities
Uptake of certain metals by forage and
gram crops from land treated with
sludge may create health risks. Pre-
1978 sludge from Chicago contained
large quantities of copper, zinc, lead,
and cadmium The Pensacola sludge
was high m zinc. Metal uptake by the
corn plant was directly associated with
soil pH The higher the soil pH the
smaller the quantity of metal uptake.
Sludge application to bermuda grass at
the 24 ton/hectare rate compared
favorably with mineral fertilizer as a
source of plant nutrients.
Samples of sludge, feed, feces, and
animal tissues (kidney, liver, spleen,
and blood) were analyzed for pathogenic
bacteria. Pathogenic bacteria were not
found to be a significant hazard.
Viruses were not detected in topsoils
eight months after spreading Pensacola
sludge. Enteroviruses represent a
minimal hazard, either through trans-
location through gram or forage or with
regard to groundwater contamination.
Samples of sludge, soil/sludge
mixture, feed, and animal tissues
(kidney, liver, fat, muscle) were ana-
lyzed for chlorinated hydrocarbon pesti-
cide residues and also polychlorinated
biphenyls. Little, if any, pesticide
residues were present in sludges used
in this research project.
Conclusions
Land spreading of urban sewage
sludge is probably the most practical
means of disposal. Sewage sludge was
shown equivalent or superior to com-
mercial fertilizers for production of
certain crops under Florida conditions.
However, uptake of metals by forage
and grain crops may create certain risks.
Metal uptake by the corn plant was
directly related to the soil pH; higher pH
levels reduced their uptake. Levels pre-
sent in gram were less than in the
forage. Cadmium levels in forage from
soils pretreated with certain sludges
resulted in high levels in liver and
kidney tissues of cattle consuming such
forage. However, performance and
carcass data of treated steers in these
studies were not different from the data
obtained with the control steers.
Clinical chemistry tests and pathologic
lesions suggested cumulative toxic
effects including liver damage.
The 1979 steer trial, where animals
grazed on forage from soils pretreated
with Pensacola sludge and spraying of
the sludge on the growing plants,
resulted in presence of Sarcosporidia
sp. in the cardiac and skeletal muscles.
This may be of public health signifi-
cance
Incorporation of dried sewage sludge
at 10 to 20 percent of swine rations pro-
duced depressed weight gains and the
21 day weaning weights were lower in
pigs from sows consuming the sludge-
containing diets The kidney cadmium
levels of sows receiving the 10 and 20
percent sludge levels were increased
significantly, i.e., four ppm for controls
and 17 and 24 ppm for the sludge
rations; both lead and cadmium were
increased in the liver and kidneys of
weanling pigs. Reproductive perform-
ance was more suppressed in the
second generation sows than in the
first
Growth trials with Cobb broiler chicks
compared the effects of poultry rations
with zero, three, and six percent dried
Chicago sludge. Increased levels of cad-
mium in the liver and kidneys occurred
in those chicks receiving the increased
levels of the sludge. However, none of
the production criteria, i.e., production,
daily feed intake, feed efficiency, egg
weights, nor body weights, were
adversely affected in Leghorn hens
receiving such modified diets.
Having demonstrated that increased
cadmium levels occurred in tissues
from cattle and swine consuming feeds
from sludge amended soils, these liver
and kidney tissues were dried, ground,
and incorporated into mouse diets. The
finished diets contained a 15 percent
level of protein and five percent levels of
kidney and liver tissue. Metals were
translocated through the cattle and
swine tissues with increased levels of
cadmium, nickel, chromium, and lead in
liver and kidney tissues of mice. These
increases m mice were associated with
decreases in number of mice weaned in
the treated versus the control groups
Analysis for pesticide residues in the
various sludges indicated that little, if
any, chlorinated residues were present.
It was concluded that these sludges
presented no hazard from the aspect of
pesticide residues.
Samples of sludge, feed, feces, and
animal tissues (kidney, liver, spleen,
and blood) were analyzed for pathogenic
bacteria. Contamination was a major
problem, both when collecting speci-
mens during the trials as well as at
slaughter. No enteric pathogens or
Mycobacteria were isolated from these
samples. There was one isolation of
Staphylococcus aureus, and two isola-
tions of Streptococcuspyogenes during
the cattle and swine trials. Two group B
Salmonella enter/tides isolates were
obtained from the feces of animals on a
sludge amended diet plus three isolates
at a later date from the same group. The
very few positive isolates suggested
that these three types of digested
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1 sewage sludges posed no significant
health hazards from bacteria.
Finally, when digested sludge was
added to a lagoon at Jay, Florida, entero-
viruses were readily detected in grab
samples from the lagoon. The level of
sludge-associated viruses dropped to
low or undetectable levels following
disposal of sludge on land and during
periods when addition of digested
sludge to the lagoon was suspended.
Enteroviruses were not detected in
wells located on the sludge disposal site
or near the lagoon
Recommendations
Present EPA guidelines on allowable
levels of certain contaminants,
including metals, would assure avail-
ability of homogeneous urban sewage
sludge which could be utilized in soil
enrichment programs for crop or forest-
lands. Further research is necessary to
assure safe rates and frequency of
application of sewage sludges, along
with other essential elements, to en-
hance crop production. If urban sewage
sludges for production of certain crops
are shown to be contramdicated, this
information should be made available.
Since certain metals, including
cadmium, lead, nickel, and chromium,
have been shown to be accumulated in
animals consuming forage or gram from
sludge-amended soils and therefore
have potential hazard to animal health
and mankind, it is proposed that further
research be done to establish safe
guideline levels in feeds intended for
meat producing animals.
The presence of Sarcocystis sp. in
muscle from cattle and swine consum-
ing sludge or forage and gram fertilized
with sewage sludge incorporated into
their diets suggest that this potential
animal and human health hazard may
be associated with consumption of
urban sludges Methods to eliminate
this hazard or prevent its infectivity
must be established prior to utilization
of sludges for crop or animal production.
Other parasites, including infective
stages of ascarids, may persist in
sludges. Destruction of parasites or
preventive programs to eliminate them
from sludge must also be developed.
Therefore, it is recommended that
research to establish the incidence,
diagnosis and factors predisposing to
Sarcocystis infection in cattle and swine
associated with sludge utilization be
initiated.
Finally, since viruses of hazard to
animal production and human health
have been shown to be present in
certain urban sewage sludges, further
research to characterize these viruses
and assure their reduction to nonhaz-
ardous levels should be continued and
completed expeditiously to allow land
application of sewage sludges as plant
nutrients
G. T Edds and J. M. Davidson are with the Institute of Food and Agricultural
Sciences, University of Florida. Gainesville, FL 32610.
Herbert R. Pahren is the EPA Project Officer (see below).
The complete report, entitled "Sewage Sludge Viral and Pathogenic Agents in Soil-
Plant-Animal Systems," (Order No. PB 81 - 179 103, Cost $18 50, 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
Cincinnati, OH 45268
> US GOVERNMENT PRINTING OFFICE 1861 757-012/7063
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Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
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