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LAND APPLICATION OF MUNICIPAL SEWAGE SLUDGE
FOR THE PRODUCTION OF FRUITS AND VEGETABLES
A Statement of Federal Policy and Guidance
U.S. ENVIRONMENTAL PROTECTION AGENTY
U.S. FOOD AND DRUG ADMINISTRATION
U.S. DEPARTMENT OF AGRICULTURE
1981
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CONTENTS
Page No.
PART I:
PART II
A Statement of Federal Policy
Technical Guidance
Plan Considerations
I. Minimum Requirements
A. Annual and Cumulative Cadmium
Application Rates
B. Soil pH
C. PCBs
D. Pathogen Reduction
II
III
APPENDIX I:
APPENDIX II:
Additional Recommendations
A. Use of High Quality Sludge
B. Cumulative Lead Application Rate
C, Pathogenic Organisms
D.*' Physical Contamination and
Filth
E. Soil Monitoring
F. Choice of Crop Type
Available Guidance and Assistance
Relative Accumulation of Heavy Metals into
Edible Plant Parts by Different Crops
Examples of Forms Used for Evaluating
Sludge Applications
APPENDIX III: References
APPENDIX IV:
Example of an Evaluation of Long-Term
Sludge Benefits
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Land Application of Municipal
Sewage Sludge for the Production
of Fruits and Vegetables
Part I
A Statement of Federal Policy
In some areas of the country, municipal wastewater sludges
have been used for many years as a soil amendment for croplands
producing fruits and vegetables. This document draws upon the
expertise within the Environmental Protection Agency, the Department
of Agriculture, and the Food and Drug Administration in providing the
first statement of unified Federal guidance for those locations where
such programs are to continue.
Since the passage of the Resource Conservation and Recovery
Act of 1976, the Environmental Protection Agency has been developing
a series of regulations which address the broad spectrum of waste
management. One segment of those regulations entitled, "Criteria
for Classification of Solid Waste Disposal Facilities and Practices"*
was promulgated on September 13, 1979, and addressed the land appli-
cation of municipal wastewater sludges for food-chain crop production,
Although promulgated by EPA, the regulation also incorporated inputs
from EPA, the Food and Drug Administration, and the U.S. Department
* Federal Register/Vol. 44, No. 179, pp. 53438-63464 (40 CFR Part 257),
September 13, 1979.
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of Agriculture. These three Agencies are responsible for maintaining
the integrity of our environment, our food products, and our agricul-
tural production, respectively.
Shortly after promulgation of the "Criteria," some food
processors raised a series of questions concerning the perceived
safety and legality of food crops grown on sludge-amended soils,
and procedures necessary to properly manage the application of
sewage sludge to land used to grow fruits and vegetables. In order
to respond to these inquiries, the EPA, FDA and USDA have collaborated
in the development of this document. It is structured upon the
"Criteria" which, in turn, embody the requirements of the Resource
Conservation and Recovery Act (RCRA) and the Clean Water Act (CWA).
It is intended to supplement those regulations and provide a
coordinated Federal perspective on the use of municipal wastewater
sludges in fruit and vegetable crop production. The document sets
forth the use of high quality sludges and proper management practices
so that growers, processors and consumers can be assured that the
current high standards of food quality in this nation will not be
compromised.
For many years the use of high quality sludges has been an
attractive source of soil conditioners and nutrients, providing
economic benefit to growers. However, many sludges also contain
substances which could contaminate such crops and make them unfit
for consumption. The contaminants of greatest concern are the
heavy metals, toxic organic compounds, and pathogenic microorganisms,
which are addressed in the aforementioned EPA regulation.
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Establishing tolerances or action levels in foods for various
sludge-borne contaminants, such as heavy metals, has been cited as
the preferred means of reducing the uncertainty associated with the
agricultural use of sludge. The Federal government is presently
developing and collecting data from survey programs to establish such
tolerances if necessary. Until the data collection and analyses are
complete, the bases for establishing tolerances will not exist.
Nevertheless, the Federal agencies believe that the use of high
quality sludges, coupled with proper management procedures, should
safeguard the consumer from contaminated crops and minimize any
potential adverse effect on the environment.
The technical guidance in Part II of this document addresses
the use of high quality sludge, maximum soil contaminant levels,
pathogen reduction, physical contamination and filth, and soil
monitoring. This guidance represents a reasoned approach, based
upon current knowledge and experience, in which risks are minimized
and continuing production of high quality food is assured.
Pursuant to other statutes beyond RCRA and CWA, such as the
Toxic Substances Control Act, the Federal Food, Drug and Cosmetic Act,
and others, the Agencies will continue to develop regulations designed
to insure proper use and disposal of sewage sludge, and this document
will not constrain that effort. As part of that rulemaking effort,
EPA will continue to evaluate new scientific data and consult with
the public. As with all regulations and guidelines, this document
will be reviewed periodically and updated, if necessary, as experience
dictates.
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Of necessity, it should be understood that by following the
guidelines of this document, the Federal government cannot offer
any indemnity against product recall, seizure, or other enforcement
actions, since these measures could result from unforeseen circum-
stances beyond the control of the Federal government. However, the
risk of such enforcement actions would be no greater than the risks
associated with normal farming or processing practices.
It is, therefore, the position of the Environmental Protection
Agency, the Food and Drug Administration, and the U. S. Department
of Agriculture that, with the adherence to the guidance contained
in Part II of this document, the safety and wholesomeness of the
fruit and vegetable crops grown on sludge amended soils will be
assured.
Administrator
U.S. Environmental Protection Agency
Secretary
U.S. Department of Agriculture
Commissioner
U.S. Food and Drug Administration
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Land Application of Municipal
Sewage Sludge for the Production
of Fruits and Vegetables
Part II
Technical Guidance
The following guidance is offered by the Environmental
Protection Agency, the Food and Drug Administration, and the
U.S. Department of Agriculture to minimize any risks and achieve
the goals of optimal utilization of sludge nutrients and production
of high quality fruit and vegetable crops. To achieve those objec-
tives, the guidance is structured upon existing regulations, coupled
with systems of good operating practices of interest to both the
grower and food processor.
PLAN CONSIDERATIONS
A written operating plan, agreed upon between the grower and
the food processor (and perhaps having the input of the State environ-
mental or agricultural department), should include consideration of
each of the following elements. In order to assure accessibility, it
is recommended that wastewater treatment plants keep a copy of this
operating plan on record.
I. Minimum requirements are the limits prescribed in the present
regulations, hereafter referred to as the "Criteria."* The
essential components of these regulations are:
* Federal Register/Vol. 44, No. 179, pp. 53438-53464 (40 CFR Part 257),
September 13, 1979
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A. Annual and Cumulative Cadmium Application Rates
Sludge shall be applied at an annual rate not to exceed 0.5
kilograms of cadmium per hectare. Cumulative loadings of
cadmium shall not exceed 5, 10, or 20 kilograms of
cadmium per hectare, depending upon background soil pH
and soil cation exchange capacity. (See Appendix IV for
an example of evaluating sludge benefits.)
B. Soil pH
Soxl pH shall be at 6.5 or greater (top six inches of the
soil) at the time of each sludge application.
C. PCBs
If the sludge contains greater than 10 mg/kg PCBs, it
must be incorporated (injected or plowed) into the soil.
D. Pathogen Reduction
The sludge must be treated by an effective pathogen
reduction process before being applied to the soil. A
12 or 18 month waiting period may be required depending
upon, a) the type of processing used to reduce pathogens
in the sludge (further pathogen reduction processes are
more effective than processes to significantly reduce
pathogens--see Appendix II of the Criteria), b) whether
the land is to provide access to the public (camping,
recreation, etc.), or c) whether it is to be used for
grazing or to grow crops for direct human consumption.
II. Additional factors presented below provide further assurance
of safe and wholesome food products:
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A. Use of High Quality Sludge
Growers should know the quality of the sludge that is
intended for application on their land. Sludge quality
information obtained from the treatment plant should
provide the following:*
1) Concentration and availability to plants of the
primary nutrients (nitrogen, phosphorus, and potassium),
the micro-nutrients (zinc and copper), and other consti-
tuents, where they would provide benefits to plants.
2) Concentrations of contaminants present in the sludge.
A high quality sludge should not contain more than 25
mg/kg cadmium, 1000 mg/kg lead, and 10 mg/kg PCBs, on a
dry weight basis. [NOTE: This level of PCBs assumes that
carrots will receive the normal processing of scrubbing
and peeling, since carrots tend to accumulate PCBs in the
skin.]
3) Type of pathogen reduction process used at the treat-
ment plant, and operating results.
B. Cumulative Lead Application Rate
In addition to maximum cumulative cadmium levels estab-
lished by the Criteria, the maximum cumulative application
of lead to the soil should not exceed 800 kilograms per
hectare. (See Appendix IV for an example of evaluating
sludge benefits.)
* (See Appendix II for examples of forms that may be used for
presenting this information.)
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C. Pathogenic Organisms
For those geographic locations which desire to provide
further assurances beyond the "Criteria," foods to be
eaten raw, or which may be processed without sufficient
blanching to destroy all pathogens, should not be planted
within 36 months of sludge application. This recognizes
that pathogen survival is greater in warm, moist environ-
ments, than in extremely arid or cold environments. The
necessary waiting period can be achieved by including, in
normal rotation, crops which are cooked or properly heat
processed (peeled, washed, etc.) prior to delivery to
consumers.
D. Physical Contamination and Filth
Sludge should be applied directly to the soil. In no
case should sludge be applied directly to growing food
crops. This will avoid the possibility of contamination
by chemicals, filth or microbiological agents. To further
avoid the possibility of contamination, crops grown on
sludge-amended soils should be processed in accordance
with good established industry practices (washed, peeled,
etc.). This is especially true for root crops and low-
growing fresh fruits and vegetables.
E. Soil Monitoring
Monitoring of soil should be performed on a regular basis
to assure consistent quality and safety of crops. Soils
should be monitored at least annually for pH. Every few
years, the soil should also be tested for the cumulative
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levels of cadmium and lead. Standard test procedures for
analysis of these heavy metals are listed in the EPA
regulations of 40 CFR Part 136 (see Appendix III).
F. Choice of Crop Type
Although high uptake crops may be safely grown as long
as the technical guidance contained in this document is
followed, growers can further preserve crop quality by
planting fruits and vegetables which tend to exclude heavy
metals. Certain fruits and vegetables, such as tomatoes
and legume vegetables, do not readily take up and translo-
cate heavy metals to edible tissues, while other types will
absorb metals to a somewhat greater degree. Appendix I
indicates the relative tendencies of fruits and vegetables
to accumulate heavy metals in edible tissues.
Ill. Available Guidance and Assistance
Growers may obtain guidance on proper agronomic methods from
USDA's Soil Conservation Service, and the county-level
Agricultural Extension Services. Additional technical infor-
mation on the subject of sludge use in fruit and vegetable
crop production is available in publications from EPA and USDA.
Some appropriate references are contained in Appendix III.
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APPENDIX I
Relative Accumulation of Heavy Metals into Edible Plant
Parts by Different Crops
High
Uptake
Moderate
Uptake
Low
Uptake
Very Low
Uptake
Lettuce
Spinach
Chard
Escarole
Endive
Cress
Turnip Greens
Beet Greens
Carrot
Kale
Collards
Beet
Turnip Root
Radish globes
Mustard
Potato
Onion
Cabbage
Sweet corn
Broccoli
Cauliflower
Snapbean family
Pea
Melon family
Tomato
Brussel Sprouts Pepper
Celery Eggplant
Berry fruits Tree fruits
The above classification is based upon the response of crops
grown on acidic soils that have received a cumulative cadmium
application of 5 kilograms per hectare.
It should not be implied that the above higher uptake crops
cannot be grown on such a soil, or soils of higher cadmium concen-
trations. Such crops can be safely grown if the soil pH is 6.5 or
greater at the time of planting, since the tendency of the crop to
accumulate heavy metals is significantly reduced as the soil pH
increases above 6.5.
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APPENDIX II
Examples of Forms Used for Evaluating Sludge Applications
Forms A and B are offered as examples of methods of organizing
soil, sludge and crop information. Form A presents the results of
soil and sludge testing for an individual landspreading site. It
also presents data on the crop to be grown. Form B, using the
information contained in Form A, presents the various sludge application
rate options. Some agricultural extension services, through the
State universities, maintain a computer program for calculating
application rates. Forms A and B are examples of the input
information and application rate output generated by such a program.
The annual application rate of sludge can be determined on
the basis of either the nitrogen or phosphorus needs of the crop.
In general, less sludge is required to supply the crop phosphorus
than the crop nitrogen needs. The amount of phosphorus applied in
excess of crop needs, that might result from determining the annual
sludge application based on crop nitrogen needs, should not generally
pose an adverse environmental problem.
The maximum annual addition of sludge that can be applied to a
given soil is based upon limiting the amount of cadmium. The total
cumulative additions of sludge that can be applied are based upon
limiting cadmium and lead. These limitations are given to protect
human health from the effect of excessive amounts of cadmium and
lead in the soil.
Also, some States limit the maximum amount of sludge that can be
added to a given soil, based upon the application of additional
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heavy metals, such as zinc, copper, and nickel. These metals do
not pose a health problem. These limitations are given rather to
protect against possible toxicity to plants. As an example, data
for these additional metals are shown in Forms A and B.
From a review of the literature, it is evident that the
methodologies for determining application rates are area and site
specific. The local agricultural extension service and/or responsible
local environmental authority should be consulted when determining
an appropriate sewage sludge application rate.
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FORM A
INPUT FORM
Name: Rudolph Tucker
Address: RR # 10
City; Centreville, Ohio
Year: 1980
Field Size: 24 acres
Crop: Carrots
Soils Information
A
B
C
D
E
PH:
5.9
Cation Exchange Capacity (CEC):
Phosphorus Test Value:
Potassium Test Value:
Lime Test Value:
Sludge Information
A. Ammonium Nitrogen (%):
B. Organic Nitrogen (%):
C. Phosphorus (P %):
D. Potassium (K %):
E. Zinc (mg/kg):
F. Copper (mg/kg):
G. Nickel (mg/kg):
H. Cadmium (mg/kg):
I. Lead (mg/kg):
J. PCB (mg/kg)
Crop Information
A. This year's crop:
B. Last year's crop:
C. Yield goal in bu/acre; cwt/acre;
or tons/acre:
27.3 & 4.8 meq/lOOg
39.9 mg/kg (79.8 Ib/acre)
330 mg/kg (660 Ibs/acre)
67
3 .0%
3.0%
2.0%
0.9%
1192
645
33.6
9.7
786
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FORM B
INFORMATION ABOUT THE SLUDGE AT ALTERNATIVE
APPLICATION RATES FOR A CARROT CROP
Sludge
ITEM
Metals
Zinc
Copper
Nickel
Cadmium
Lead
PCBs
Nutrients
Nitrogen
-Required
-From Sludge
Phosphate ^205)
-Required
-From Sludge
Potash (K20)
-Required
-From Sludge
Sludge value
this year
Assuming 2.3 tons/acre
1
Application
2
Rates
3
(tons/acre)
4
5
6
Ib/acre
2.3
1.2
0.05
0.02
1.5
0.0
85
72*
75
91*
0
22
40.
lime
4.7
2.5
0.1
0.04
3.1
0.0
85
144
75
182
0
43
$/Ton
5 25.5
required to
7.1
3.8
0.2
0.06
4.7
0.0
85
216
75
272
0
65
21
raise
9.5
5.1
0.2
0.08
6.2
0.0
85
288
75
363
0
86
18.7
soil pH
11.9
6.4
0.3
0.10
7.8
0.0
85
360
75
454
0
108
17.1
to 6. 5
14.3
7.7
0.4
0.12**
9.4
0.0
85
432
75
545
0
130
14.1
* Approximately 1 dry ton/acre of this sludge will provide the
crop's nitrogen and phosphorus needs.
** 0.12 Ibs Cd/acre is equivalent to 0.13 kg Cd/ha; maximum annual
Cd application = 23 T/A to reach 0.5 kg Cd/ha in soil.
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APPENDIX III
REFERENCES
EPA REGULATION AND GUIDANCE
0 "Criteria for Classifxcation of Solid Waste Disposal Facilities
and Practices" (40 CFR Part 257), Federal Register, September 13,
1979.
0 "A Guide to Regulations and Guidance for the Utilization and
Disposal of Municipal Sewage Sludge," EPA 430/9-80-015-MCD-72.
0 "Municipal Sludge Management - Environmental Factors,"
EPA 430/9-77-004, MCD-28, October 1977.
8 Sludge Treatment and Disposal, Volume II, October 1978.
Technology Transfer (Design Seminar Series), EPA 625/4-78-012.
0 "Guidelines Establishing Test Procedures for the Analysis of
Pollutants" (40 CFR Part 136).
USDA GUIDANCE
0 Utilizing Municipal Sewage Wastewaters and Sludges on Land for
Agricultural Production. North Central Regional Extension
Publication No. 52. November 1977.
0 Applications of Sludges and Wastewaters on Agricultural Land:
A Planning and Educational Guide, March 1978. North Central
Research Publ. 235. (Reprinted by EPA Office of Water Program
Operations, MCD-35.)
0 Utilization of Wastes on Land: Emphasis on Municipal Sludge,
National Workshops. Sponsored by USDA, Anaheim, Calif.,
Aug. 12-14, 1980. (Unpublished report available from Hunter
Follett, Dept. of Agronomy, Kansas State University, Manhattan,
Kansas 66506.)
OTHER GUIDANCE
0 Miller, R. H. The Ohio Farm Bureau Federation (OFBF) and
research project on land application of municipal sewage
sludges. Proceedings of the Second Annual Conference of
Applied Research and Practice on Municipal Industrial Waste.
Madison, Wise., September 17-21, 1979. 321-333 p.
0 Ohio Guide for Land Application of Sewage Sludge Research
Bulletin 1079 (revised), Ohio Agricultural Research and
Development Center. Bulletin 598 (revised), Cooperative
Extension Service, Ohio State University.
0 Application of Sewage Sludge to Cropland: Appraisal of Potential
Hazards of the Heavy Metals to Plants and Animals. November 1976,
Council for Agricultural Science & Technology, Report No. 64.
EPA 430/9-76-013.
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APPENDIX IV
EXAMPLE OF AN EVALUATION OF LONG-TERM SLUDGE BENEFITS
Knowledge of sludge quality will allow an assessment of the
long-term consequences of sludge use. If, for example, a sludge
which contains 5 percent available nitrogen and 2.5 percent
phosphorus is applied to a soil at rates which would supply either
the nitrogen or phosphorus requirements of the crop, compliance
with the Criteria regulations could easily be achieved (assuming a
high quality sludge with a cadmium concentration of 10 mg/kg, and
a lead concentration of 250 mg/kg). If such a sludge were applied
at a rate of 1 dry metric ton per hectare (which would supply the
phosphorus requirements of most vegetable or fruit crops), or 4 dry
metric tons per hectare (which would supply the nitrogen require-
ments of most vegetable or fruit crops), the sludge could be used
on the same field for 125 to 500 years before reaching the Criteria
limitations on cumulative additions of cadmium, or the recommended
maximum cumulative additions of lead. Although the cumulative
cadmium or lead application limits may eventually be reached, the
soil would remain suitable for the growth of all food-chain crops,
including fruits and vegetables, providing that no additional sludge
is used.
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