25217-3
BACKGROUND DOCUMENT NO. 3
HAZARDOUS fcftSTE MANAGEMENT SYSTEM: GENERAL;
STANDARDS APPLICABLE TO OWNERS AND OPERATORS
OF HAZARDOUS W^STE TREATMENT, STORAGE, AND DISPOSAL
FACILITIES; AND HAZARDOUS WASTE PER1IT PROGRAM
(40 CFR 260, 264, and 122)
Permitting of Land Disposal Facilities: Land Treatment
This document (ms. 1941.36) provides background
information on EPA's proposed regulations for
land disposal of hazardous waste
U.S. ENVIRONMENTAL PROTECTION AGENCY
July 1981
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TABLE OF CONTENTS
INTRODUCTION Page 4
I. NEED FOR REGULATION Page 7
II. ANALYSIS OF STANDARDS Page 8
1. Applicability - §264.270 Page 8
2. General operating requirements - §264.272 Page 10
ISSUE; Surface water run-on and run-off
3. Waste analysis - §264.273 (Reserved) Page 13
4. Food-chain crops - §264.276 Page 15
A. Proposed Regulation and Rationale Page 15
B. Summary of Comments Page 23
C. Discussion Page 25
(l)-(9) Response to comments
(10) Summary Page 29
D. Regulatory Language Page 35
5. Unsaturated zone (zone of aeration)
monitoring - §264.278 Page 37
ISSUE; "Soil and soil-pore water monitoring" Page 37
A. Proposed Regulation and Rationale Page 37
B. Summary of Comments Page 39
(1) Soil monitoring vs ground-water monitioring
(2) Soil monitoring Page 41
(a) Sampling procedure
(b) Depth of sampling Page 42
(c) Corrective action Page 43
C. Discussion Page 45
(1) Soil Monitoring vs Ground-water Monitioring
(2) Soil Monitoring Page 46
(3) Summary Page 52
D. Regulatory Language Page 53
6. Recordkeeping - §264.279 Page 54
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7. Closure and Post-closure - §264.280 Page 56
A. Proposed Regulation and Rationale Page 56
B. Summary of Comments
(1) Return of soil to preexisting condition. Page 58
(2) Use of the Extraction Procedure (EP) on soil. Page 58
(3) Soil removal: closure as a landfill. Page 59
(4) Suggested alternative closure requirements. Page 59
C. Discussion
(1) Return of soil to preexisting condition. Page 60
(2) Use of the Extraction Procedure (EP) on soil. Page 61
(3) Waste removal: closure as a landfill. Page 62
(4) Alternative closure approaches. Page 63
D. Regulatory Language Page 65
8. Special Requirements for;
Iqnitable or Reactive Wastes - §264.281
Incompatible Wastes - §264.282 Page 67
9. Special Requirements for
Classes of Facilities - §264.283 Page 71
III. REFERENCES Page 73
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INTRODUCTION
Requirements for land treatment facilities (formerly called
landfarms) were proposed on 18 December 1978 (43 FR 58946-59028).
Numerous comments were recieved on that proposal at public hearings
and as written comments. A summary of the comments and Agency
responses, pertinent to the Part 264 regulations, is presented in
Part II of this document. The reader is also referred to two
other background documents:
(1) Background Document, Section 250.45-5, Standards for
Landfarms (Land Treatment Facilities), U.S. EPA, Office
of Solid Waste, December 15, 1978.
(2) Background Document, Section 265.270, Final Interim Status
Standards for Land Treatment Facilities, U.S. EPA, Office
of Solid Waste, April 30, 1980.
In the 30 April 1980 background document, under the heading
"Changes in Terminology" the Agency discussed the basis for adopting
the term "Land Treatment Facility" in place of "Landfarm". In this
discussion, the Agency also set forth its philosophy with respect
to land treatment as a waste management technique. That discussion
is supplemented below.
The basic philosophy of the agency is that the application of
hazardous waste to the soil is a waste management practice reserved
for those waste streams that are treatable in a soil system.
Although the Agency has a good general understanding of what types
of wastes or when wastes should or should not be land treated it
has been difficult to translate that understanding into an acceptable
regulation to cover all types of wastes and facility designs and
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operating procedures which may be used in land treating wastes.
The problem is how to specify which wastes may or may not be land
treated under what circumstances and to clarify what constitutes
treatment. Questions which arise include the following:
0 How much of the waste must be treatable and how is this to be
measured?
0 Should the regulations distinguish between the treatability
of the organic fraction versus the inorganic fraction; between the
factors which caused the waste to be classified as hazardous versus
other factors?
0 How much organic degradation is enough to qualify for land
treatment?
0 How much should be known about degradation byproducts and
their mobility, toxicity, or degradability?
0 How much less mobile or less toxic is sufficient and how are
these to be measured?
0 Should reversible immobilization reactions be considered
treatment?
Even though many of these questions remain unanswered, the
/gency supports the position that the principal objective of land
treatment is the biological and chemical degradation of organic
waste constituents (See 45 FR 33205). The Agency maintains that
land treatment should be, as the name implies, reserved for those
wastes that can be treated in a soil system. Although not yet
able to define treatment qualitatively or quantitatively for
regulatory purposes, the Agency considers treatment at land treatment
facilities to include the biological and chemical degradation of
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organic wastes, the neutralization of wastes that have high or low
pH (i.e., corrosive wastes), and the relatively irreversible
conversion of inorganic constituents to a less mobile or less
toxic form.
The Agency acknowledges that land treatment consists of both
treatment and disposal. For example, some metals may be immobilized
in the soil and are in that sense treated; these metals also persist
in the soil (i.e., do not degrade) and are in that sense disposed.
The Agency feels that the greater the degree of treatment a waste
undergoes in the soil the more acceptable that waste is for land
treatment. A waste which contains a principal component that is
irreversibly degraded, irreverisbly neutralized, made less mobile,
or made less toxic, is considered to be an ideal candidate for land
treatment.
The Agency does not believe, except in special cases (e .g .,
neutralization of corrosive wastes, or where it is known that
essentially irreversible chemical reactions occur), that land
treatment is the appropriate method of waste management for hazardous
wastes that are primarily inorganic in composition (e .g .,
electroplating sludges, inorganic pigment sludges). In most cases,
such wastes can best be managed by alternative methods.
Along the same lines the Agency does not consider using the
soil solely as a filtration or dilution medium as an acceptable
land treatment practice. Filtration and dilution provide little or
no net reduction in hazard if they do not alter the chemical state
of the waste.
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It is evident from the preceding discussion that developing a
standard which satisfies the land treament objective by generically
screening wastes is not yet possible. Until many of the questions
raised in this discussion can be answered the determination of
whether or not a waste is suitable for land treatment will be left
to the discretion of the owner or operator of the land treatment
facility and the permit issuing authority.
Although an owner or operator may misuse this discretion,
there is an incentive, independent of Agency or state review, that
encourages the reasonable use of discretion. The incentive is the
reduced long-term liability, which can be achieved by land treating
wastes that undergo a high degree of treatment in the soil (e.g.,
wastes that are composed of predominantly degradable organics, or
wastes that are hazardous due solely to high or low pH). Land
treating such wastes could substantially reduce the post-closure
care responsibilities of §264.117{d) and therefore the costs
associated with post-closure care. Reduction of the post-closure
care responsibilies would be contingent upon the owner or operator
demonstrating that the waste/ and any byproducts of degradation
that are of concern, have been treated and rendered innocuous.
I. NEED FOR REGULATION
The need for regulation of land treatment facilities has been
covered in the background document " Subpart M - Interim Status
Standards of Land Treatment Facilities" dated 30 April 1980. The
basis for the need to regulate land treatment facities presented
in that document does not need to be supplemented to support the
general status regulations being proposed.
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II. ANALYSIS OF STANDARDS
1. Applicability - §264.270
A. Proposed Regulation and Rationale
The applicability of the proposed standards was discussed
in the preamble to proposed December 18, 1978 regulation (Hazardous
Waste, Proposed Guidelines and Regulationions and Proposal on
Identification and Listing, 43 FR 58982). Applicability was further
delineated by the definition of land treatment, then referred to as
landfarming. Land treatment was defined as the application of
waste onto land and/or its incorporation into the surface soil,
including the use of such waste as a fertilizer or soil conditioner.
B. Summary of Comments
N/A
C. Discussion
The Part 264 land treatment regulations contain a specific
applicability standard which differs from the standards proposed
in December 1978 primarily in that the term (landfarm) applied to
the practice has changed. The definition a of land treatment
facility applicable to interim status has been amended to reflect
the fact that waste may or may not remain in place after closure.
As proposed, the definition of a land treatment facility in Part
260 of the regulations reads as follows; "Land treatment facility
means a facility or part of a facility at which hazardous waste is
applied onto or incorporated into the soil surface.
The practice has been furthur described in the preamble to
Types of facilities - §264.19(a) as follows; "Land treatment
facilities are facilities at which waste; usually in a solid,
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semi-solid, semi-liquid, or liquid state; are spread on the
surface of the ground for the purpose of treatment. Discharge to
the groundwater normally occurs as leachate. Discharge to the
surface waters normally occurs both by erosion and as leachate
mixed with ground water. Discharge to the atmosphere normally
occurs as diffuse gaseous eraisions. Wastes are nearly always left
in place at closure ."
This description not only encompasses the definition by
describing in a physical sense the practice of land treatment, it
also describes the: purpose of land treatment, physical nature
of the wastes that are land treated, mechanisms by which discharges
may occur, media affected by the discharges, and the ultimate fate
of the wastes upon closure of the facility.
The most significant aspect of this description is the statement
that the purpose of land treatment is treatment. Discussion on this
Agency attitude is presented in the introduction to this document
and in the preamble to these regulations at 46 FR 11144-45. The
bottom line of the discussion is that the Agency considers land
treatment to be a waste management practice reserved for those
waste can be successfully treated in a soil system. Although this
interpretation of land treatment has been difficult to translate
into qualitative and quantitative terms, the Agency's objective is
to encourage the efficient use of the soil as a treatment medium
while discouraging irresponsible parties from characterizing
indiscriminate dumping of waste as land treatment. The Agency
acknowledges that not all of the constituents of a waste will be
treated, e.g., degraded, immobilized, detoxified or neutralized.
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Some waste constituents will inevitably persist in the soil and in
that sense are disposed. The fact that disposal occurs due to
residuals being present in the soil in which treatment occurs, as
well as due to liquid migration and gaseous emissions, is reflected
in the portion of the land treatment description which states that
"wastes are nearly always left in place at closure."
D. Regulatory Language
The regulations in this Subpart apply to owners and operators
of hazardous waste land treatment facilities, except as §264.1
provides otherwise.
2. General operating requirements - §264.272
ISSUE; Surface water run-on and run-off
A. Proposed Regulation and Rationale
Requirements for control of surface water run-on and run-off
were proposed under §250.43 (b) and (c) . Those regulations would
have required the owner or operator to construct diversion structures
capable of preventing run-on from entering a land treatment facility.
A variance to this requirement was allowed where an owner or operator
could demonstrate to the Regional Administrator that run-on would
not enter the site and come in contact with the hazardous waste.
The regulations would also have required the owner or operator to
collect and confine run-off from active portions of the facility
to a point source before discharge or treatment.
B . Summary of Comments
See the 30 April 1980 background document, which references
comments presented in the background document "Subpart N - Interim
Status Standards for Landfills" dated 2 May 1980.
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C . Discussion
The requirements under the general status regulations are
equivalent to the requirements under interim status. The comment
to the interim status requirements has been deleted.
In the Part 264 regulations land treatment facilities are
subject to the same requirements as landfills regarding surface
run-on and run-off. Run-on must be diverted away from the active
portions of the land treatment facility. Run-off from the active
portions must be collected. If the collected run-off is a hazardous
waste it must be managed as a hazardous waste. If the run-off is
not a hazardous waste but it is allowed or caused to infiltrate the
land on site, it will have to be permitted as a leachate discharge.
If the run-off is not a hazardous waste and it is to be otherwise
removed from the site, it may still need to be analyzed, treated,
or otherwise managed to comply with Subtitle D of RCRA or the
Clean Water Act.
EPA believes that run-on and run-off controls are necessary
at land treatment facilities because this disposal option involves
the placement of hazardous waste on or just beneath the soil surface.
Because the waste is exposed during the application and incorporation
process, the potential for loss via surface water erosion is
initially high. During site operation, the potential for run-off
to become contaminated is directly related to the frequency and
rate of waste application. In the long term, the potential for
run-off to be contaminated is further increased as refractory
waste contaminants becomes concentrated in the surface soil.
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The release of dissolved or suspended waste contaminants
or contaminated sediment from a land treatment facility can have
adverse human health and environmental effects. One damage case,
involving contamination of a lake by run-off from an oily waste
land treatment facility, has already been documented (1). At
another oily waste land treatment site in Texas, surface run-off
from experimental plots were found to contain 30-100 mg/1 of oil (2).
The study concluded that "oil and nutrient contents of the rainfall
run-off water from the soil cultivation [land treatment] process
can be relatively high, and this discharge water should receive
treatment before entering public waterways." This conclusion was
supported by another study which cited the low tolerance of aquatic
organisms to certain trace elements as the major reason for
controlling run-off (3).
The fqency acknowledges that the surface area of the active
portions of a land treatment facility will generally be large,
relative to the active portions of landfills. Consequently, more
extensive run-on diversion structures and run-off collection systems
will be needed at land treatment facilities. The overall impact
of run-on and run-off controls is expected to be somewhat tempered
since most land treatment facilities already have diversion
structures and collection systems (4). The Agency does not
anticipate that all the run-off that is collected at land treatment
facilities will require treatment prior to discharge. Evidence in
the literature suggests that if the waste is thoroughly incorporated
into the soil, contamination of run-off can be minimized or
prevented. At an oily waste land treatment facility in Texas, it
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was found that after thorough waste incorporation, there was no
significant difference between the quality of run-off from
experimental and control plots (5). Agricultural pesticide run-off
studies have shown that run-off quality improves with the length
of the storm event and with the length of time since the last
pesticide application (3). These phenomena are paralleled in land
treatment facilities.
These studies strongly suggest that run-off may need treatment
only during certain periods, for example, run-off that is collected
at the beginning of a storm event or immediately after waste has
been applied. Once wastes have been incorporated into the soil,
and the wastes have been degraded or the soil surface stabilized
by crusting or vegetation, collected run-off is expected to require
little or no treatment.
D. Regulatory Language
(a) Run-on must be diverted away from the active portions
of a land treatment facility.
(b) Run-off from active portions of a land treatment
facility must be collected.
3. Waste analysis - §264.273 (Reserved)
A. Proposed Regulation and Rationale
The waste analysis requirements in §250.43 of the proposed
regulations applied waste analysis to all treatment, storage, and
disposal facilities, including land treatment. The waste analysis
requirements included: determination of the hazardous constituents
and properties of the waste prior to initial disposal; verification
of certain properties of each waste shipment received; and periodic,
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comprehensive analysis of waste if there were indications of changes
in composition.
The reasoning behind the proposed recordkeeping requirement
was discussed in the background document on waste analysis. In
brief, the purpose was to ensure that a facility owner or operator
had sufficient current information to manage the waste without
endangering human health and the enviroment.
B. Summary of Comments
Comments on the proposed waste analysis requirements are
discussed in the May 1980 Background Document on Waste Analysis.
C. Discussion
The requirements for Waste Analysis have been deleted because
this section was thought to be redundant with the requirements
order §264.13, General waste analysis, and the information
requirements of §122.25(d). An owner or operator is required
under §264.13 to analyze the waste to the extent necessary to land
treat the waste, and under 122.25(d) to define the hazardous waste(s)
that will be land treated and predict the mass rate of hazardous
waste and decomposition byproducts that are expected to leach or
otherwise escape from the site.
Given these requirements and the comprehensive waste analyses
needed to comply with them, the Agency felt the waste analysis
requirements of §264.273 were unnecessary.
The above discussion is reproduced from the preamble at 46 FR
11145 correcting an error referencing §264.21 instead of §122.25(d).
D. Regulatory language
N/A
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4. Food-chain crops - §264.276
A. Proposed Regulation and Rationale
The proposed regulations prohibited growing of food-chain
crops on the treated area of a land treatment facility. The purpose
of the proposed regulations was to protect humans from consuming
toxic materials that may contaminate human or animal food grown on
land to which hazardous waste has been applied.
Several routes exist by which food-chain crops grown on land
treatment facilities may be contaminated by hazardous waste
constituents. These are: uptake by plants of the hazardous
constituent from the soil, and transfer to the edible portion of
the plant; adherence of a waste to crop surface; and ingestion of
the waste by grazing animals.
There are many factors which influence the degree to which
various hazardous constituents may be transferred along these
routes. These include: the chemical, physical, and biological
characteristics of the waste; the method of application; the rate
of application; season; climate; soil characteristics (including
soil type, moisture content, pH, cation exchange capacity of the
soil (CEC), hydrous-oxide content, and biological and
microbiological activity); the type of crop grown; the method of
planting; time and method of harvest, etc.
The information available on the extent to which organic or
inorganic substances are actually translocated to crops is limited.
Many of the studies which have been done are the subject of a
great deal of controversy. For example, many studies failed to
include pH effect on metal accumulation, thus the knowledge of pH
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effect on metal accumulation is insufficient. Also, there are
varying opinions on the validity of extrapolating greenhouse data
to represent actual field conditions.
In addition to the difficulties involved with predicting and
controlling the various factors which influence the transfer of
hazardous constituents to food-chain crops, there is only limited
information available regarding "safe" levels of various substances
in crops. Although the Food and Drug Administration expresses
concern about the growing of food-chain crops on waste amended
soils, no qualitative or quantitative guidance, except for PCBs*,
has been given as to what levels of toxic metals or other hazardous
constituents in crops would protect human health.
Also, presentations in the literature on this subject do not
always clearly distinguish plant toxicity from animal toxicity.
It is recognized that toxic effects to crops can provide some
protection for crop consumers (animal and human). However,
accumulation of hazardous constituents in crops without signs of
plant toxicity creates the opportunity for human exposure to
potentially harmful substances. The reported levels of hazardous
constituents in crop tissues are sometimes misinterpreted. Care
is not always taken to distinguish between data on the edible and
nonedible portions of the crop. However, even the "nonedible"
portions of the crop may be used for animal feed so that a particular
hazardous constituent may still enter the food chain. Also,
nonharvested portions of the crop may remain in the soil where the
Finished animal feeds are the only crops for which FDA has set a
PCB tolerance level. This tolerance level is 1.2 ppm in feeds
that are given to animals consumed by humans.
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hazardous constituents could remain and become available for
subsequent uptake.
While the state of knowledge about translocation of hazardous
constituents to crops is incomplete, the Agency does have information
to suggest that there is a significant cause for concern that
translocation of some of the hazardous constituents to food crops
could endanger public health.
The cause of the Agency1 s concern regarding growth of food-chain
crops on land treated with waste is exemplified by a variety of
actual incidents, studies, and projections. It should be noted
that although many of the incidents described here do not relate
specifically to land treatment of hazardous wastes, the concerns
they raise are still pertinent to this program. The concerns
relate to ingestion by animals, vaporization or direct adherence
to crops, and plant uptake.
It is known, for example, that almost any hazardous waste
could be metabolized through direct ingestion by grazing animals.
Soil is ingested by grazing animals along with herbage from the
adhering to leaves, from soil on roots, and from earthworm casts.
In the case of a land treatment site, the soil is likely to be a
mixture of soil and waste. Factors influencing soil/waste ingestion
include the type of animal, the type of soil and type of forage,
stock density and other management variables, rainfall, and earthworm
populations (6,7).
Grazing animals have been estimated to ingest soil in amounts
ranging from 2 to 14 percent of the diet (8). Healy has shown that
soil can make up as much as 8 percent of the dry matter intake of
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grazing cattle (9). Furthermore, cattle have been observed grazing
on land used for the application of industrial sludges (10).
In 1976, in Bloomington, Indiana, municipal sludge laden with
PCBs was applied to pasture land which was grazed by a single
dairy cow. The PCS levels of the sludge ranged from 240 to 1,700
ppm and soil levels in the pasture reached 200 ppm PCBs (11). As a
result of grazing in this pasture, the cow's milk contained 5 ppm
PCBs (fat basis), and was thus not fit for human consumption.
(The FDA tolerance for unavoidable PCBs in milk shipped interstate
commerce is 1.5 ppm.)
Other instances of the transfer of toxic organic compounds
from pasture soil to grazing animals have been reported. In Gossimer,
Louisiana, hexachlorobenzene was accidentally spilled onto pasture
land, resulting in the impoundment of 20,000 cattle, until levels
of the contaminant in these animals were reduced (12). In Maryland,
heptachlor used for the control of weevils in alfalfa was later
found to have contaminated the milk of grazing animals (13).
Harrison et al., have shown that soil containing DDT residues can
supply considerable amounts of total DDT to ewes and that these
residues can be transferred to lambs (14).
Some organic wastes may vaporize and redeposit on the tissue
of plants. While few studies have been done in this area,
information has been developed which shows that lipophilic (oil)
crops like soybeans tend to take up lipophilic hyrdrocarbons like
chlorinated hydrocarbon insecticides. Also, the surface of the
leafy plants can become contaminated with small amounts of these-
materials, resulting primarily from their vaporization from the
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soil and redeposit on the plants. The risks of the contamination
in this instance is under study (15).
The adherence of toxic substances to crops is another avenue
for transfer. The likelihood of surface contamination occurring
is greatest when liquid waste are applied directly to growing
crops, or when the edible portion of the plant is in direct contact
with treated soil. An example of surface contamination by the
second means is a case where DDT was once applied routinely to
sweet corn in large amounts to control the corn ear worm. It has
since appeared on the surface of carrots grown in the same fields,
and has made those carrots unsuitable for sale (12).
Nearly all of the published work on adherence of land-applied
wastes to growing crops is based on application of municipal sludge.
However, Batey, et al., found high levels of copper and zinc in or
on crops sprayed with swine manure slurries (16). Boswell found
high levels of cadmium, lead, and chromium on foliage following
application of municipal sludge filter cake (16). Chaney and Lloyd
have shown that municipal sludge applied to pasture grass can,
shortly after application, result in the adhered sludge making up
30 percent of the dry weight of the crop (17). Rainfall and
weathering over an 80-day period did not remove much of the sludge
from the grass. However, the 80 days of growth permitted a dilution
of the weight of the sludge to the weight of the crop. Still, at
the end of the 80-day period, 5 percent of the dry weight of the
grass was actually found to be adhered sludge. This study was
performed in the rainy east, and therefore, one would expect that
sludge application to grasses in more arid regions would result in
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even greater adherence of the sludge to the crops. A greenhouse
study by Jones et al., using simulated rainfall, resulted in similar
conclusions to those of Chancy and Lloyd (18). Once the sludge had
dried on the grass, rainfall was not effective in reducing the
amount of adhered sludge. Rainfall was found only to be effective
if it occurred immediately after sludge was applied.
Heavy metals, such as cadmium, molybdenum, selenium, mercury,
and lead, can be absorbed by crops from the soil of land treatment
facilities. The uptake of mercury and lead by most crops, however,
is not nearly of the magnitude of these other metals.
Cadmium may be taken up by plants even though only very low
levels exist in the soil. The transfer of cadmium from the soil
to plants is well documented in the background document supporting
EPA's recently promulgated Criteria for Classification of Solid
Waste Disposal Facilities and Practices. Crops such as leafy
vegetables or root crops take up significantly greater amounts of
cadmium than do grains or grasses.
Maintaining a near-neutral pH on a land treatment facility to
control plant uptake of most heavy metals can lead to an increase
in the uptake of molybdenum and selenium. These two metals are
more soluble at neutral and basic pH's. Molybdenum's toxicity has
been a serious problem in livestock food production in certain
areas of the western United States. Forages grown on naturally
wetr alkaline, or neutral soils can contain toxic concentrations
of molybdenum (19). Certainly, the land application of wastes high
in molybdenum to such soils would aggravate this naturally-occurring
problem.
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In Oregon, a study using shredded municipal waste at an
application rate of 900 metric tons per hectare resulted in a
significant uptake of molybdenum by alfalfa. The levels reached
would have been potentially hazardous to likestock if only one
feed source was used (20).
Land treated wastes do not generally increase levels of mercury
in plants. However, Van Loon found very considerable levels of
mercury in tomatoes where municipal sludges (the highest containing
25 ppm mercury) were used (18,21). Results of Yugoslav studies
showed that mercury levels of most plants were low ( 1 to 50 ppb)
compared to the mercury content of soils in which they grew (100
to 600 ppm). Carrots, grasses, and some weeds had more mercury
(800 ppb) than other plants. Jackson found that mercury in the
tops of barley and soybean plants whose roots were in a mercury
solution came from mercury vapor released from the roots, rather
than from translocation. If mercury volatilizes from waste-treated
soils, plants could absorb it (22).
Significant increases in the lead content of some crops as a
result of soil application of lead have been reported, particularly
in soils deficient in phosphate (23). Because of the buffering
capabilities of soils and plant roots, as well as absorption and
precipitation phenomena, most lead in soils is not likely to be
translocated to the above-ground portions of plants. Hswever,
uptake to the above-ground portions can be appreciable following
changes in the environmental and physiological condition of the
plant (24). In fact, investigations of existing land treatment
sites have indicated that significant increases can occur in the
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lead content of crops, such as clover and various grasses (22).
In general, a minimal amount of toxic organic compounds are
absorbed by plant roots and transferred to other parts of the
plant. Organics with large molecules, such as pesticides and
PCBs, do not tend to pass the semipermeable membrane of plant
roots. Consequently, plants possess the ability to exclude large
organic molecules added to soils, which result in minimal impact
on the quality of forage and grains (21). An exception is
organochlorine pesticides which are absorbed by plant roots and
transferred to other parts of the plant, but at a very low rate
compared to the concentration in the soil (24).
The absorption of PCBs by plant roots and translocation
within plants is considered minimal, but some studies have reported
what appeared'to be low levels of plant uptake as a result of
heavy application rates (25). These studies further suggest,
however, that PCBs are not actually taken up by the plant but,
rather, are physically adsorbed on the surface of the roots (21).
The examples do suggest that there are known cases where
translocation of toxic substances to crops has occurred, and that
there is a significant potential for contamination of crops from
soils treated with hazardous wastes to crops grown on that soil.
The Agency also examined the benefits to be gained from growing
food-chain crops in treated soils. The Agency believes that such
benefits are minimal. Certainly the very small amount of land
so used is not needed for food growth from a national perspective.
It represents a negligible portion of the total productive land
for crops needed for food growth from a national perspective. It
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represents a negligible portion of the total productive land for
crop growth available in this country. Furthermore, there are
other productive uses of such land, for example, crop farming of
non-foodchain crops, if crop growth is desired. The Agency
recognizes that growth of food-chain crops can result in a source
of revenues to help defray disposal costs. However, the Agency
does not believe that such revenues minus the cost of growing and
marketing the crops, especially in light of the cost of waste and
crop monitoring and other controls needed to ensure protection of
public health, are significant to the economic viability of land
treatment.
The Agency considered the alternative of specifying safe
application rates of various wastes to the soil for growth of food
crops. The Agency also considered establishing safe levels of
various substances in plants and requiring crop monitoring to
control potential hazards. As the above discussion points out,
the data and information base available for such an approach does
not exist.
In view of all of the above considerations, the Agency concluded
that it should ban the growth of food-chain crops on hazardous
waste land treatment facilities.
B. Summary of Comments
0 The term "food-chain crops" means tobacco; crops
grown for human consumption; or crops grown for pasture,
forage, or feed grain for animals whose products are
consumed by humans.
0 The regulation is too restrictive. If studies of
plant tissue residues and crop uptake demonstate that
the crop will not take up the hazardous constituents,
growth should be permitted.
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The restriction will abolish the practice of growing
food chain crops at land treatment facilities. EPA
should require tests to determine if crops grown on
such land are suitable for consumption by humans or
livestock
Growth of food-chain crops should be permitted if, after
study over two growing seasons, the consumable part of
the crop can be shown to be non-toxic.
The regulation is too restrictive. It should be
replaced with a requirement for monitoring of crop
uptake of hazardous constituents.
The regulation is too restrictive. The regulations
should take into consideration the hazardous characteristics
of the waste, the nature of the soil, and the substance
being taken up by crops. Growth should be allowed.
The regulation should be based on application rates of
waste, rather than a prohibition. EPA should develop
regulations controlling application and specifying
testing requirements.
The issue is blown out of proportion. Many hazardous
wastes are phytotoxic, which makes growth of any crop
impossible. However, other wastes are amenable to land
treatment on crop land.
Growth of food-chain crops should not be prohibited
without qualification. Certain crops and grasses have
assimilative capacity for a variety of potential
hazardous waste, e.g., bermuda grasses. Without their
use, land treatment facilities would have to be bigger.
The prohibition is inconsistent with EPA's position on
POTW sludge. Textile sludges present no greater toxic
potential than POTW sludges.
Studies have shown that land treatment of utility ash
and sludge do not result in unsafe levels of potentially
hazardous contaminants in crops. Gypsum and fly ash
are used routinely to correct soil deficiencies. An
exception should be provided where reasonable evidence
and studies show that there is no substantial hazard
to human health.
The regulation would prohibit using waste lime as a
soil conditioner on crop lands. Waste limes from the
sugar beet refining process or from lime kilns have
high levels of CaC03 (85 percent) and MgC03 (5 percent),
which neutralize acid soils. Waste lime from beet
processing has been in use for 25 years.
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0 Crude oil does not have as high a concentration of
heavy metals as other waste oils. It has been
demonstrated that waste crude oil adds nutrient value
and that it is perfectly safe to grow crops on land so
treated.
0 The regulation would eliminate land treatment of waste
for beneficial uses, i.e., as agricultural fertilizers.
It would raise disposal costs by 700 percent. Thus,
there is a poor risk and benefit ratio for a ban.
0 The prohibition is totally appropriate, since there is
very little information on toxics and persistent
organics beyond the work on metals in POTW sludges.
Until data are developed on crop uptake of these other
toxins, land contaminated with them should not be used
for agricultural purposes.
C. Discussion
The following discussion is based largely on the above comments,
The substance of the comments are paraphrased as numbered items (1)
through (9), and discussion pertinant to the paraphrased comment
follows. The last numbered item is a summary discussion of basis
for the requirements as the Agency as set them forth in the
reproposed regulations.
(1) Food chain crops should be defined.
A definition for "food chain crops" was provided in the
proposed rules on page 58997, Section 250. 41{ b) (33). The same
definition is included in the final interim status regulations.
The definition reads: "Pood chain crops" means: tobacco; crops
grown for human consumption; or crops grown for pasture, forage,
or feed grain for animals whose products are consumed by humans."
This definition does not preclude the growing of a crop which is
normally consumed by humans or animals if the crop is only grown
as a ground cover and then plowed under.
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(2) Monitor crop uptake.
The option of analyzing a crop for uptake of hazardous
constituents is conceptually attractive, but presents certain
problems in practice. The most basic problem is that crop tolerance
levels have not been established for most of the hazardous
constituents of concern; hence, there is no standard of comparison.
However, the Agency does believe that crop monitoring represents
an acceptable general approach when comparing hazardous constituents
in the crops to background levels. Comparing crops grown on land
treatment facilities with crops grown in nontreated soils is the
only feasible way of applying crop monitoring in most situations,
due to lack of defined tolerance levels. The revised regulatory
language permits an owner or operator to present such data to the
Agency as a part of the support for a claim that growth of a crop
on a land treatment facility presents no danger to public health.
(3) Prescribe acceptable application rates. Base the standard
on the characteristics of the waste, the soil, and the
crop being grown. Many wastes are amenable to land
treatment on cropland.
This approach, perhaps coupled with crop monitoring, would
be an ideal approach if the state-of-the-art would support it.
Unfortunately, this is not the case. Except for cadmium,
information on acceptable application rates is not available for
combinations of soil, hazardous wastes, and crops. Consequently,
this approach is not feasible as a general approach at this time.
Such an approach is used for cadmium, however, because there is
sufficient data to support it. Efewever, the Agency believes that
it is important to begin to develop this information through
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monitoring of conditions in a land treatment facility. Furthermore,
the Agency believes that an owner or operator should have the
opportunity to demonstrate to the Agency that it has developed
such information for a particular situation. This concept is
also embodied in the interim status standards.
(4) Certain crops and grasses have assimilative capacity for
potentially hazardous substances, e.g., bermuda grasses.
The regulation should be qualified to allow their growth.
The proposed regulation is not without qualification in
that only food chain crops are restricted. Crops which are not
used for human consumption or consumed by animals whose products
are not consumed by humans are not restricted. Therefore, a crop
such as bermuda grass can be grown at a land treatment site for
the purpose of assimilating waste components or providing ground
cover. In this case, the grass could not be used as an animal
feed for animals whose products are consumed by humans. Because a
food chain crop is defined by its end use, crops which may normally
be considered food chain crops can be grown at a land treatment site
if adequate measures are taken to prevent its consumption by humans
or animals whose products are consumed by humans.
(5) The prohibition is inconsistent with Subtitle D regulations.
Textile sludges present no greater hazard to crop growth
than wastewater treatment sludge.
The ^ency agrees that the approaches are currently different.
ftjwever, the cadmium standards established in the Criteria have
been incorporated into the interim status standards in order to
have consistency between those two regulations. The requirements
concerning PCB in the Criteria were not included at this time.
This issue will be resolved as part of the consideration between
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the RCRA programs and the Agency program for handling PCB under
the Toxic Substance Control Act. Also, the interim status standards
will provide an owner or operator the opportunity to present data
showing that crop growth on such waste is safe.
(6) Utility ash and sludge is beneficial to some solids;
presents no hazard to crops.
The interim status standards will allow an owner or operator
to grow food chain crops at a land treatment facility, provided
there is data indicating that such a practice does not pose a threat
to public health. Therefore, the owner or operator of a land
treatment facility receiving utility ash and/or sludge may grow
food chain crops provided he can document that such crops are
safe.
(7) The regulation would prohibit using waste lime as a soil
conditioner on crop lands.
The Agency acknowledges the point raised by this comment
and has exempted waste lime from this prohibition if it is only
classified as a hazardous waste due to its high pH. This provision
is specified in Part 261.
(8) Crude oil adds nutrient value to the soil, and crop growth
on land so treated is safe.
As with all waste which is classified hazardous, the interim
status standards will allow an owner or operator to grow food chain
crops at a land treatment facility provided there is data indicating
that such a practice does not pose a threat to public health.
(9) The prohibition wold eliminate land application of hazardous
waste for use as agricultural fertilizers and raise disposal
costs by 700 percent.
No data to support the claim of a 700 percent cost increase
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were provided, and the Agency disagrees strongly with this estimate.
Since the prohibition only applies to the growing of crops for
human consumption or for consumption by animals whose products are
consumed by humans, the Agency does not believe that this restriction
will result in a major impact on the land treatment of hazardous
wastes. Because food chain crops often have a higher market value
than non-food-chain crops, there may be some reduction of income
from land treatment sites. However, because many non-food-chain
crops are often grown on less productive lands, the agricultural
fertilizer value of the hazardous wastes may be better utilized by
these crops. Thus, the Agency sees no clear or significant benefit
from growing food chain crops.
(10) Summary discussion.
The Agency proposed a ban on the growth of food-chain crops
at hazardous waste land treatment facilities. After reviewing
comments, EPA decided that during the interim status period,
food-chain crops may be grown, provided that certain requirements
are met. The Agency's decision not to continue with the ban during
the interim status period is based on the following reasons:
First, there exist insufficient data to indicate that the growth
of food-chain crops at a hazardous waste land treatment facility
would always create a risk to those who consume such crops. Second,
banning the growth of food-chain crops would be inconsistent with
the regulatory approach taken to protect food-chain crops under
Subtitle D of RCRA. These regulations were finalized as the Criteria
for Classification of Solid Waste Disposal Facilities and Practices
(40 CFR 257) on 13 September 1979.
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The Agency believes it would be unjustified to impose a ban on
the growth of food-chain crops at land treatment facilities if
there were convincing evidence that the crops can be grown without
posing a significant public health risk. It is conceivable that a
substance in a hazardous waste may not be taken up by certain
food-chain crops, or after a period of treatment, the substance
may degrade into products non-hazardous to humans.
For example, some wastes may be used to control pH of the
soil, and there may be a significant body of data which supports
that such a use does not pose a public health risk. The Agncy does
not wish to prohibit such uses of waste, realizing that the waste
may simply be replaced with commercial product containing the same
chemical constituents as the waste.
The cadmium standards detailed in the Criteria do not set
limits for food-chain crops, but instead prescribe annual application
rates and limits on cumulative loading based on the specific health
risk posed by cadmium. As a result, a waste, regardless of the
cadmium concentration, may be applied to land on which food-chain
crops are grown. Compliance with the Criteria can be achieved
merely by applying less waste. The Agency believes it would be
unjustified in banning the growth of food-chain crops at facilities
receiving waste that is hazardous due to cadmium, since such a waste
can be applied in a manner that would not violate the standards
prescribed in the Criteria.
The Agency, while not considering a ban appropriate because of
the reasons mentioned, had to deal with the task of how to structure
the regulations to permit the growth of food-chain crops, and at
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the same time be assured that public health would be protected. In
order to achieve this, the Agency devised a two-part test to
determine whether food-chain crop growth on land treatment facilities
is acceptable. The two-part test requires the owner or operator,
prior to growing a crop, to demonstrate that the hazardous waste
constituents in the waste, as well as arsenic, lead and mercury
will not (a) be transferred to the edible portion of the crop by
plant uptake, by direct contact or by transfer to food-chain animals;
or (b) occur in greater concentrations in the crop than in crops
grown on control soils under similar circumstances in the region.
In order to demonstrate comparability, an owner or operator
must use actual field studies. A test plot would be considered an
acceptable field study. Also, the conditions under which the
comparable crops are grown must be similar to the conditions found
at the facility, for example, soil type, soil moisture, soil pH,
soil nutrients, photo period and length of growing season, must be
similar at both facility and control sites. The owner or operator
must also document the sample selection criteria, sample size
determination, analytical methods and statistical procedures used
to make the demonstration. In order to establish compliance
prior to waste application, the owner or operator must pre-test
samples of the crop using the type of waste and application rate
that will be used at the facility. The sample must be that portion
of a crop which would be consumed (e.g., corn kernel, wheat grain
etc) .
The two-part test approach is based on the premises that since
the Agency does not have a clear specification of the "no risk"
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level of such contaminants in food crops, it is reasonable to assume
that the level of such contaminants presently in food crops is
acceptable. However, future research data may indicate that health
tolerances in food crops should be higher or lower than the average
levels otherwise present in such crops.
Arsenic, lead, and mercury were specifically identified
because of their relatively high toxicity to humans and evidence
that they can be taken up by crops (26). Mercury can enter plants
through the roots and be readily translocated throughout the plant.
Arsenic tends to accumulate in the roots of most crops, which is a
concern when root crops such as radishes, carrots, etc., are grown.
When in high concentrations in the soil, lead has been shown to
translocate to crops.
The Agency is concerned that there are other hazadous substances
in the wastes, e.g., toxic organics, that may be taken up by crops.
The difficulty in identifying toxic organics is due to the lack of
data in this area. Most crop studies have addressed only inorganics
or pesticides; thus there is a paucity of data on the uptake of
many other toxic organics by crops. However, the Agency will
identify other hazardous substances of concern as information
becomes available.
In order to be consistent with the Criteria for the
Classification of Solid Waste Disposal Facilities and Practices,
the standard developed in those regulations for cadmium has been
incorporated into the interim status regulation. Thus the cadmium
standard present in the Criteria will be applicable to hazardous
waste land treatment facilities.
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The Criteria include two approaches for the land application
of wastes containing cadmium. The first approach incorporates four
site management controls; control of the pH of the waste and soil
mixture; annual cadmium application limits that are reduced over
time; cumulative cadmium application limits based on soil cation
exchange capacity (CEC); and restriction of the cadmium concentration
in waste applied to facilities where tobacco, leafy vegetables and
root crops are grown.
The second approach allows unlimited application of cadmium
provided that four specific control measures are taken: first, the
crop grown can only be used as animal feed. Second, the pH of the
soil must be maintained at 6.5 or above for as long as food-chain
crops are grown. Third, a facility operating plan must describe
how the animal feed will be distributed to prevent human ingestion:
Fourth, future owners are provided notice (through provisions in
land records of property deed) that there are high levels of cadmium
in the soil and that food-chain crops should not be grown.
The Agency believes that the Interim Status Standards adequately
protect public health, and therefore has adopted a similar approach
for the proposed regulations under this section. Ffowever, one
section of the Interim Status Standards has been modified for the
purpose of this section. The modification is the deletion of the
"phasing" approach for the annual application of cadmium. Under
this approach the annual application or cadmium is reduced over a
set period of time. The time schedule starts from the present to
June 30, 1984 and allows 2.0 kg/ha of cadmium to be applied. From
July 1, 1984 to December 31, 1986 the amount is reduced to 1.25
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kg/ha, and further reduced to 0.5 beginning January 1, 1987.
The cadmium limits promulgated under Subtitle D of RCRA are
primarily aimed at controlling wastewater treatment sludges
containing high levels of cadmium from being placed on agricultural
lands. The phased time period for the reduction of cadmium applied
to agricultural lands is used inorder to correspond with the
pretreatment schedule that wastewater treatment facilities (POTW's)
must meet, in accordance with the Clean Water Act, to reduce the
amount of cadmium in their sludges. The Agency believes that by
using the same schedules, implementation of the regulation can be
carried out without causing an undue hardship on operators of
wastewater treatment facilities, and at the same time be assured
that public health will be protected.
Because the phased schedule for controlling the annual
application of cadmium is oriented primarily towards wastewater
treatment sludges, the Agency has decided not to incorporate it
into regulations under this Section. Instead, the 1987 annual
cadmium application rate of 0.5 kg/ha is used. The Agency feels
that it is more appropriate to use the 1987 cadmium limits since
most wastewater treatment sludges probably will not be classified
as hazardous wastes, and to apply the phased time period to waste
other than wastewater treatment sludge would be contrary to its
original purpose. However, in the future, the phased schedule for
annual cadmium application rate may be incorporated into the
regulations under this Section if the Agency finds that large
quantities of wastewater treatment sludge are falling within the
hazardous category. Also, it should be noted that the Agency is
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currently developing regulations under Section 405 of the Clean
Water Act that will address cadmium limits applied to food-chain
crop lands. These regulations, when promulgated, may make it
necessary for the Agency to modify existing cadmium limits in order
to have consistency in its approach to control the application of
cadmium to food-chain crop lands.
D. Regulatory Language
(a) Owners or operators of land treatment facilities who propose
to grow food chain crops after the effective date of this Part
must comply with paragraphs (b) and (c) of this section.
(b)(l) Food chain crops must not be grown on the treated area of
a hazardous waste land treatment facility unless the owner or
operator can demonstrate, based on field testing, that arsenic,
lead/ mercury, or other constituents:
( i) Will not be transferred to the food portion of the crop by
plant uptake or direct contact, and will not otherwise be ingested
by food chain animals (e.g., by grazing); or
(ii) Will not occur in greater concentrations in the crops grown
on the land treatment facility than in the same crops grown on
untreated soils under similar conditions in the same region.
(2 ) The information necessary to make the demonstration required
by paragraph (a)(1) of this section must be kept at the facility
and must, at a minimum:
(i) Be based on tests for the specific waste and application
rates being used at the facility; and
(ii) Include descriptions of crop and soil characteristics,
sample selection criteria, sample size determination, analytical
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methods, and statistical procedures.
(c) Food chain crops must not be grown on a land treatment
facility receiving waste that contains cadmium unless all
requirements of paragraph (c)(l)(i) through (iv) of this section
or all requirements of paragraph (c)(2)(i) through (iv) of this
section are met.
(l)(i) The pH of the waste and soil mixture is 6.5 or greater
at the time of each waste application, except for waste containing
cadmium at concentrations of 2 mg/kg (dry weight) or less;
(ii) The annual application of cadmium from waste and soil
cadmium does not exceed 0.5 kilograms per hectare (kg/ha).
(iii) The cumulative application of cadmium from waste and soil
cadmium does not exceed 5 kg/ha if the waste and soil mixture has
a pH of 6. 5.
(iv) If the waste and soil mixture has a pH of 6.5 or greater,
or is maintained at a pH of 6.5 or greater during crop growth, the
cumulative application of cadmium from waste and soil cadmium does
not exceed: 5 kg/ha if soil cation exchange capacity (CEC) is less
than 5; 10 kg/ha if CEC is 5-15; and 20 kg/ha if soil CEC is greater
than 15.
(2)(i) The only food chain crop produced is animal feed.
(ii) The pH of the waste and soil mixture is 6.5 or greater at
the time of waste application or at the time the crop is planted,
whichever occurs later, and this pH level is maintained whenever
food chain crops are grown.
(iii) There is a facility operating plan which demonstrates how
the animal feed will be distributed to preclude ingestion by humans.
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The facility operating plan describes the measures to be taken to
safeguard against possible health hazards from cadmium entering the
food chain, which may result from alternative land oses.
{iv) Future property owners are notified by a stipulation in
the land record or property deed which states that the property has
received waste at high cadmium application rates and that food
chain crops should not be grown, due to a possible health hazard.
5. Unsaturated zone (zone of aeration) monitoring - §264.278
ISSUE; Soil and soil-pore water monitoring
A. Proposed Regulations and Rationale
The proposed soil monitoring requirements included:
0 Determine background soil conditions by taking one soil core
per acre in the area to be treated at a depth of three times
the depth of the zone of incorporation, or 30 centimeters,
whichever is greater. The bottom one-third of the soil core
must be analyzed for the hazardous constituents in the waste.
At new facilities, the cores must be taken prior to beginning
operation. At existing facilities, the cores must be taken
within six months of the effective date of the regulations.
0 Soil conditions in the treated area of a land treatment site
must be determined by taking one soil core per acre
semiannually at three times the depth of the zone of
incorporation, or 30 centimeters, which is greater. The
bottom one-third of the core must be analyzed for the
hazardous constituents in the waste.
0 If soil monitoring shows that the concentration of a
hazardous constituents significantly exceeds background
levels, the owner/operator must: (1) notify the Regional
Administrator within seven days, (2) determine the areal
extent of vertical contaminant migration, and (3) discontinue
all land treatment in the contaminated area until corrective
measures are taken.
There were three basic elements to this proposed procedure,
each with a separate rationale. These elements were the sampling
procedure (i.e., number of samples) , the depth of the core samples,
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and the corrective action required. The sampling procedure was
based largly on subjective reasoning of how many samples would be
required to obtain an adequate representation of the soil in the
land farm. The requirement was not based on a statistical test.
The corrective actions specified were based on the assumption
that migration of contaminants to a depth of three times the depth
of the zone of incorporation constituted a potential threat to
public health and the environment, and that no further land treatment
should occur until this situation was corrected, as determined by
the Regional Administrator.
Perhaps the most significant element of the requirement was
the selected depth of three times the depth of the zone of
incorporation as the "performance standard" for the facility. This
standard was based on a number of technical studies which suggested
that in a properly designed and operated land treatment facility,
there should be little or no migration of contaminants beyond the
zone of incorporation.
The Agency has identified a considerable amount of literature
and empirical data indicating limited waste migration at hazardous
waste land treatment facilities.
A literature review by Page (27) in 1974, evaluated the
potential hazards of the application over 10 years of sewage
treatment plant wastes to agricultural soils. Page found that in
most soils, the percentage of heavy metals (Ag, Ba, Cd, Co, Cr,
Cu, Hg , Mn, Ni , Pb, Sn, and Zn) , applied in the form of sludge
which move beyond the depth of tillage, is quite small. This same
phenomenon has been observed in field studies where oily hazardous
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waste has been land treated. Meyers and Huddleston (28) applied
oil refinery waste (API Separator Sludge, tank bottoms, slop oil)
at three different application rates over a period of three years.
The study indicated no significant leaching or migration of organic
or inorganic waste constituents. Similar findings were reported
by Kincannon (2) in his review of an 18-month field study conducted
in 1971. Three types of oil feed materials were selected to
represent different combinations of hydrocarbon types. The oil
types included oil tank bottoms, bunker C fuel oil, and waxy oil.
Neither oil nor nutrients (added as fertilizer) migrated vertically
during the study.
A state-of-the-art study (3 ) on land treatment of municipal
and industrial wastes found -no incidents of water pollution at any
of the six sites studied. Soil sampling at these sites suggested
that heavy metals and trace elements appear to be retained in the
zone of incorporation.
B. Summary of Comments
(1) Soil monitoring vs. ground-water monitoring
° Neches1 land treatment research supports EPA's conclusions
that soil monitoring will detect any migration long before
ground-water monitoring could detect it.
0 Ground-water monitoring at land treatment facilities is
unnecessary, especially with the proposed siting and
surface controls outlined in §250.45-5(b) and (c).
0 Because our own data has shown little migration, we strongly
support soil monitoring in lieu of ground-water monitoring.
If, at some later time, soil monitoring indicates significant
migration, ground-water monitoring could be commenced.
0 Because the published literature clearly shows little
migration, we strongly support soil monitoring lieu of
ground-water monitoring.
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0 The proposed soil monitoring program is not adequate to
protect ground water resources. Some potential ground-water
contaminants migrate slowly through soils; however, there
are many potential contaminants that can migrate very
quickly through soils, depending on soil conditions and
waste characteristics. Situations could exist where
potential ground-water contaminants would migrate to ground
water and not be detected by semiannual soil monitoring.
0 EPA could not identify a single incident of ground-water
contamination resulting from land treatment of hazardous
wastes, which would indicate that the soil monitoring
requirements are overly restrictive and should be replaced
by test wells at the property line. Soil monitoring should
be performed, but for day-to-day operations, not for
compliance monitoring.
(2) Soil monitoring
(a) Sampling procedure (number of samples; extent of analysis)
0 Analyzing for all hazardous components is unreasonable and
expensive. Should analyze only "as necessary" to detect
vertical migration of wastes. It is beyond present day
knowledge to analyze for all hazardous constituents since:
- many wastes are very complex and variable in composition
- quantitative analysis may not show biological activity
or the chemical form of some components.
- very few labs have the expertise or equipment to do
quantitative analysis of soil samples, and there are
few standardized analysis procedures
Because of the above, one should analyze for indicators or
tracers, such as bromide.
0 Should analyze for degradation products rather than wastes,
as applied. Should change the regulation to "analysis as
necessary to detect vertical migration of hazardous
constituents."
0 Accumulation of waste constituents in the soil should be
compared with "acceptable" levels of those constituents
rather than with background.
0 The number of samples and extent of analysis is excessive
for low hazard wastes, and would be expensive ($200-5400
per sample). Should analyze only for major species unless
migration is detected. For example, large treatment areas
with uniform terrain and cover crop would hardly require
so many samples and would result in redundant data.
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Analyzing for all constituents which make the waste
hazardous is overkill, also. (Comment listed 28 substances
which potentially would have to be monitored for fly ash
and scrubber sludge.) Should analyze for major species
initially, such as Ca, Na, 804, etc. If migration is
indicated, then more extensive trace analysis could be done.
No methods were provided for obtaining core samples, and
there is an absence of analysis methods and methodology
for determining background condition. Should require a
minimum of 10 background samples and not less than one per
acre.
Soil monitoring and comparison to background analyses is
too vaguely described. Suggest that a periodic report of
analyses be required and that the definition of
"significantly exceeded background levels" be more
scientifically specified.
Should define significant increase over background .
Suggest defining significant increase in terms of number
of samples, i .e .:
Significant Increase
No. of Samples over Background
1 1.2
2 1.4
3 1.6
4 1.8
One sample per acre is arbitrary and unreasonable. Soil
samples are time-consuming and expensive, and should be
minimized. Five samples are sufficient--one on each corner
and one in the center of the facility, for plots of 50
acres or less.
For background purposes, one core per acre is excessive
and expensive. Should sample the four corners and middle
of the treated area. If these samples show inconsistencies,
then additional samples could be taken.
The cost of sampling large land treatment areas will be
exorbitant and for no good reason. Uniformity of the
soils in the tract can be determined by sampling of the
four corners and middle of the site.
Should allow a variance for the owner or operator to show
that his sample will give representative results.
Far fewer than one soil core per acre would accomplish
adequate testing at three times the depth of the zone of
incorporation. Testing of each acre, if necessary, should
be confined to the actual zone of incorporation.
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0 Background and treated soil conditions can be determined
without requiring one core per acre. A more rational and
reasonable requirement would be one soil core per 10 acres,
but not less than one core per treated area.
0 The total number of soil core samples to be analyzed
annually is excessive and should be reduced by either
taking fewer samples per total acreage as acreage increases,
or lengthening the sampling frequency from semiannual to
annual. Suggest the following to give adequate quantities
of soil core samples to be analyzed:
- one core per acre for 5 acres or less
- one core per 1.5 acres for 6 to 9 acres
- one core per 2 acres for 10 to 30 acres
- one core per 4 acres for greater than 60 acres
0 One soil core per acre represents considerable redundancy.
Samples should be taken to represent specific areas
receiving specific wastes at particular application rates.
An area receiving a specific waste mix at a uniform
application rate throughout the area should be treated as
a single unit for soil sampling and analysis.
0 Testing of a subsample of composited samples from several
different locations in an area receiving a particular waste
at a particular application rate should be allowed.
(b) Depth of sampling (three times the depth of
the zone of incorporation)
0 Limiting migration to three times the depth of the zone of
incorporation is arbitrary and unreasonable. Application
to the surface should not be more limited in penetration
limits than deeper application. Migration limits should
be based on case-by-case conditions and should allow the
owner/operator to demonstrate that no ground water threat
exists.
0 Limiting migration to three times the depth of the zone of
incorporation is not acceptable. Should allow migration
to a depth safely above the shallowest usable ground water.
Some land treatment faciities may be underlain by a hundred
feet of non-water-bearing soil capable of absorbing
contaminants.
0 Application of wastes with high solids content will raise
the surface of the land treatment facility gradually,
eventually causing problems with the definition of the
zone of incorporation. Suggest that core depths be
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determined from the initial depth and location of the zone
of incorporation.
0 A fixed core depth, such as three feet, should be established
from the initial level of the zone of incorporation. The
reason is to take advantage of the assimilative capacity
of the soil to arrest transport of contaminants, yet
provide a reasonable depth for monitoring to assure that
the transport is not excessive. These requirements have
nothing to do with the depth to which the soil was plowed,
so should not be tied to that depth. This overcomes the
problem of defining a (sample) depth when waste is not
plowed at all.
0 Surface soils should be sampled as protection for the land
treatment facility operator, since soil composition can
change dramatically with depth and composition of surface
soils are subject to change due to various ma ran ade activities
and emissions.
0 The soil monitoring requirements should be broadened to
include anaerobic operations. Aerobic and anaerobic
operations do not occur in the same locations in the soil
profile and final monitoring should not be done until
after the last operation in the sequence. An example is
denitrification. A high nitrogen waste would yield nitrate
in the aerobic zone within 12 inches of the zone of
incorporation. Further down, the nitrate will denitrify
(convert to nitrogen gas) under proper conditions. Soil
monitoring locations do not relate to the zone of
incorporation in this case.
0 The limitation on significant increase of hazardous
contaminants below the zone of incorporation is in conflict
with the planned dilution of certain inorganic ions in the
ground water, i.e., chloride. A waste may be hazardous
because of its concentrations of chloride or sulfate. It is
well recognized that the chloride does not degrade and
will eventually dilute in the ground water. This should
be recognized in the regulations.
0 We agree with the depth of three times the depth of the
zone of incorporation, or 30 centimeters, whichever is
greater, for taking soil samples.
(c) Corrective action
0 Requiring land treatment facilities to cease operations
and perform corrective actions upon detecting an increase
above background may force land treatment facilities to
close when no threat to underground drinking water supplies
or human health exists. Instead of requiring that operations
be discontinued, EPA should require that the magnitude of
the threat to area ground water be determined and that,
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based on this analysis, the Regional Administrator may
order the land treatment facility to be closed and/or
corrective action taken. Requiring the owner/operator to
cease operations and take corrective action is justified
if human health and the environment are endangered.
However, a significant increase over background does not
necessarily constitute a threat. Soil monitoring should
be used to indicate when further investigation is warranted
to determine if corrective action is necessary.
This comparison with background and corrective action
restricts the mechanism by which land treatment functions.
Concentrations of constituents added to a land farm will
certainly increase in the zone of incorporation and, to
lesser extent, at the depths cited. Otherwise, such
constituents would have had to be discharged either to
ground or surface waters. The fact that background levels
have been exceeded in no way demonstrates that the soil's
capacity for assimilation has been reached. The regulation
should establish "safe levels" at which constituents can be
applied and assimilated.
The requirement that operations be discontinued until the
Regional Admiminstrator determines what actions are to be
taken is unnecessarily strict and violates due process.
It is too stringent because it ignores the possibility of
analytical error, the importance of the finding in the
particular circumstance, and the consequences of the
closedown decision. It should be sufficient to require
immediate notice to the Administrator and, perhaps, the
requirement to conduct more frequent sampling and analysis.
The Regional Administrator always has recourse to the
imminent danger provisions of RCRA Section 7003. The
proposal violates due process rights of the owner/operator,
as no standards are established for RA determinations,
nor is the RA required to make his determination within a
particular time. Thus, the RA has absolute discretion,
both as to when he will make a decision and what the
decision will be.
Merely detecting contaminants below the zone of
incorporation does not constitute a threat to ground
water. The regulations seem to assume that any migration
of contaminants to poses a hazard to ground water. This
assumption is not true. Soil monitoring is a useful tool
that should not be relied upon totally to provide ground
water protection.
In the event that a significant increase of hazardous
constituents appears below the tilled depth, what is the
recommended correction procedure? Complete removal and
landfilling of the fill? Is it presumed that this senseless
approval of land spreading of hazardous waste is an attempt
to justify the advocation of extensive and almost
uncontrolled sewage sludge farming?
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C. Discussion
(1) Soil monitoring vs. ground-water monitoring.
Comments received on this issue clearly favored some form
of soil monitoring over ground-water monitoring, however, several
commenters felt that ground-water monitoring was also necessary.
These commenters contended that soil monitoring had certain
limitations (e.g., low reliability of detecting highly mobile
contaminants) , "and should not be solely relied upon to provide
protection of our ground-water resources." The Agency recognizes
that rapidly migrating contaminants could be missed by soil
monitoring. Recently, researchers at Texas A&M have discovered
that organic compounds migrated through field tests plots at a
rate that was three times faster than water (29). The waste applied
to the test plots was API separator sludge. This waste is commonly
land treated at many oil refineries.
Additional impetus for ground-water monitoring came indirectly
from the commenters who were dissatisfied with the Agency's
interpretation of what constituted contamination. The regulations
required remedial measures if contaminants migrated to three times
the depth of the zone of incorporation. This facet of soil
monitoring, which will be discussed in detail later, was considered
to be arbitrary and precluded using the full capacity of the soil
to attenuate waste. Ground-water monitoring, as required for
landfills and surface impoundments, would provide a more consistent
and clear determination of environmental impact at land treatment
facilities.
Given the concern over the limitations of soil monitoring and
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the claim that the Agency's interpretation of contamination is
arbitrary, ground-water monitoring is now required at land treatment
facilities during interim status. The requirements are the same as
for surface impoundments or landfills.
The Agency has three reasons, in addition to those raised in
the comments, for requiring ground-water monitoring at land treatment
facilities. First, many of the land treatment facilities covered
in existence today have not operated under the philosophy of "limited
waste migration." Contaminants at these sites are likely to have
already migrated beyond three times the depth of the zone of
incorporation. Soil monitoring, as proposed, would provide no
information on the depth, concentration, or type of contaminants
that have migrated beyond the depth to which soil cores are taken.
Second, at existing facilities new unsaturated zone monitoring
(both soil and soil-pore water monitoring) is not reliable in
indicating if contaminants have already migrated to ground water
and what impact they may have on ground water. The only sure way
to know at existing facilities is to monitor ground water. Third,
ground-water monitoring will be used to confirm predictions made
on the fate of leachate leaving the zone of incorporation from
both new and existing facilities. This is an integral part of the
Part 264 approach to rigorously protect ground-water resources.
(2 ) Soil monitoring
Responses to the comments on the proposed soil monitoring
regulations are discussed collectively to facilitate presentation
of the revised monitoring scheme for land treatment facilities.
Cne of the most prevalent points made by commenters was that
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the sampling frequency should be other than one core per acre.
Most of the comraenters felt that the one soil core per acre
requirement was excessive and the cost exorbitant. Several
alternative sampling schemes were suggested, including:
0 The number of soil cores should be variable until more
research can be performed.
0 A minimum of 10 cores and not less than one core per acre
should be required, regardless of site size.
0 An incentive to take more than one core per acre could be
provided by making what constitutes a significant increase,
a function of sample size, i.e., if one core per acre is
taken, then an increase in the level of a contaminant of
1.2 times background would be considered a significant
increase: if two cores per acre were taken, then a
significant increase would be 1.4 times background, etc.
0 For landfarms of 50 acres or less, take one core near each
corner of the site and one from the center.
0 Take one soil core per 10 acres, but not less than one soil
core per treated area.
0 The number of soil cores taken per acre should be a function
of land farm size, e.g.,:
Landfarm Size (in acres) Core Per Unit Area
5 1 core/acre
6-9 1 core/1.5 acres
10-30 1 core/2 acres
31-60 1 core/3 acres
>60 1 core/4 acres
0 Allow compositing of samples taken at one core per acre in
areas where only one type of waste or waste mix is applied
at a uniform rate.
Each of the above proposed sampling schemes, as well as the
approach proposed in the regulations, is deficient in not being
linked to a test of statistical significance for comparison with
background levels. The Agency felt that the soil monitoring scheme
had to have a statistical basis since it was a regulatory tool used
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in determining if enforcement action would be taken at a facility.
Because of the Agency1 s decision to require ground-water monitoring
at land treatment facilities, soil monitoring will not play an
enforcement role. Soil monitoring will still be required, however,
it will be structured differently and will be used to substantiate
predictions made about the movement of leachate in the unsaturated
zone.
Commenters suggested analyzing for tracers or indicator
substances, rather than for the broader range of hazardous components
that could be in a waste. Cost was cited as a reason for this
suggestion. Lack of sufficient analytical capacity and procedures
was also mentioned. It was suggested that due to waste degradation,
the form of chemical components might change, making it uncertain
what actual hazardous constituents were present.
The Agency does not agree that there is a lack of analytical
capacity and procedures to carry out a comprehensive analysis. No
evidence was presented to support that contention, and the experience
of the Agency strongly suggests that this is not the case.
Concerning degradation byproducts, the Agency had decided
that the owner or operator will have to know or predict what
degradation byproducts will be formed as a result of land treatment.
Section 122.25(d) requires the owner or operator to define the
hazardous waste(s) that will be land treated and predict the mass
rate of hazardous waste and decomposition byproducts that are
expected to leach or otherwise escape from the site.
Use of indicator substances does have merit from a cost and
simplicity standpoint. Conceptually, if one could select a substance
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in the waste which was known to migrate in the soil at least as
rapidly as any other substances in the waste, then it could be
monitored as an indicator. If that substance was detected as having
migrated, then a more comprehensive analysis for other substances
should be carried out. During the permitting process, an owner
or operator will have the opportunity to supply data to the Agency
supporting the use of indicator substances in lieu of repeated
comprehensive analyses.
The issues of soil-core depth and corrective action are
discussed together since they are closely related. In the
regulations it was proposed that soil cores be taken to a depth of
three times the zone of incorporation. If migration of contaminants
was detected, as indicated by an increase in waste constituents
over background levels in the bottom one-third of the core, then
the owner or operator was to cease operation in the affected area,
notify the Regional Administrator, and determine corrective action.
Some commenters objected to the monitoring depth of three
times the zone of incorporation as being less desirable than a
fixed core depth. Three feet was suggested. It was argued that
depth of tillage was not relevant in determining environmental
performance. In contrast, several commenters felt the support for
the proposed monitoring depth was appropriate.
The proposed monitoring depth was critized for the corrective
action required if migration to that depth occurred. Commenters
argued that the fact that migration to the specified depth had
occurred was not an indication of actual or potential environmental
damage, and that the corrective action proposed was excessive.
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In consideration of the comments received on soil monitoring,
and upon further analysis of the alternatives available the Agency
has revised its approach to monitoring the environmental performance
of land treatment facilities. The environmentally sensitive nature
of land treatment requires the owner or operator to have an accurate
picture of the movement of contaminants in the unsaturated zone.
EPA has decided that such an objective requires a more comprehensive
monitoring plan than was proposed. The new plan will require soil
monitoring, using soil cores, and in addition, the owner or operator
will be required to monitor the soil-pore water, using lysimeters
or similar devices. This new monitoring scheme, now called
"unsaturated zone (zone of aeration) monitoring", although requiring
an additional type of monitoring, is structured so that it will
provide the owner or operator with the flexibility necessary to
develop a site-specific monitoring plan.
Although lysimeter monitoring was not proposed in December 1978,
it is necessary, because, as commenters pointed out, soil monitoring
will not detect rapidly migrating waste constituents. Given the
comments on contaminant migration, and indications from an
EPA-sponsored study that some organic compounds are apparently
capable of rapid migration (29), it is evident that soil monitoring
may not adequately detect contaminant migration and that soil-pore
water monitoring may also be needed. The need for more comprehensive
monitoring is further justified by the fact that land treatment
facilities characteristically lack liners.
Unlike landfills and surface impoundments the use of lysimeters
or similar devices is feasible at land treatment sites. Lysimeters
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can be installed at land treatment facilities in the area where
waste has been applied. This is not practical for existing surface
impoundments and landfills. In addition, the relatively shallow
depth of waste application at land treatment facilities permits
lysimeters to be replaced at both existing and new facilities, when
they become clogged or otherwise nonfunctional. Furthermore, land
treatment facilities do not have artificial liners which would
interfere with the placement of lysimeters. The advantage of
monitoring soil-pore water is that this type of monitoring will
detect contaminants passing through the soil, whereas soil monitoring
does not detect what passes through, but what has been left behind.
The timing of soil-pore water sampling is very important. The
sample(s) must be taken when soil-pore water from waste application
is present in the sampling device. This is a function of when the
waste is applied, the water content of the waste, precipitation,
soil permeability, and depth of the lysimeter.
Soil-pore water monitoring in combination with soil and ground-
water monitoring will provide comprehensive knowledge about the
performance of the facility and its ability to protect ground water.
This monitoring approach will also provide information on the mass
balance (i.e., location, distribution, concentration) of contaminants
in the unsaturated zone. This type of information is not only
necessary from a regulatory (environmental performance) standpoint,
but is requisite to understanding how a land treatment system
functions. Using the monitoring data as feedback on the performance
of a site, an owner or operator can more effectively manipulate
operating variables in order to optimize the performance of the
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site (e.g., waste application rates, tilling frequency, and pH
controls) .
The regulations for unsaturated zone monitoring are structured,
as discussed previously, to provide the owner or operator with the
flexibility necessary to design a monitoring program which takes
into account site-specific factors. The regulation includes a list
of factors and relationships that must be taken into account when
developing the plan. The owner or operator must maintain all data
collected and make it available for review upon request by the
Regional Administrator, and must submit all the data in conjunction
with Part B of the application for a permit in accordance with
Section 122, Subparts A and B. The unsaturated zone monitoring
information will be particularly useful in developing the closure
and post-closure care plans. This approach is intended to accommodate
inherent differences between sites, and stimulate innovation of
more efficient monitoring methods and plans.
(3) Summary
The Agency has revised the monitoring requirements at
hazardous waste land treatment facilities. Because of concerns
raised by some commenters over the inability of soil monitoring to
detect highly mobile contaminants, the Agency has decided to require
ground-water monitoring at land treatment facilities. Further
impetus for ground-water monitoring came from the need for a more
clear determination of what constitutes contamination at a land
treatment facility. Additionally, the Agency needed a mechanism
for evaluating the total impact that land treatment facilities
have on the environment. This evaluation is considered necessary
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in light of the fact that land treatment facilities are expected
to result in the discharge of leachate to ground water.
Significant changes were made to the proposed soil monitoring
regulations in response to both public and in-house comments. The
proposed soil monitoring scheme has been replaced with a more
comprehensive unsaturated zone monitoring scheme. Soil-pore water
monitoring, using lysimeters or similar devices is required in
addition to soil monitoring. Although the new scheme is more
comprehensive than the proposed regulations, it is structured to
give the owner or operator the flexibility necessary to develop a
site-specific monitoring plan.
D. Regulatory Language
(a) The owner or operator must have in writing, and must
implement, an unsaturated zone monitoring plan which is designed
to characterize the leachate that is expected to leave the zone of
incorporation and substantiate the predictions made under
§§122. 25(d) (2) and (3) and 122.28(f)
(b) The unsaturated zone monitoring plan must include, at a
minimum:
(1) Soil monitoring using soil cores, and
(2) Soil-pore water monitoring using devices such as lysimeters.
( c) To comply with paragraph (a)(l) of this Section, the owner
or operator must demonstrate in his unsaturated zone monitoring
plan that:
(1) The depth at which soil and soil-pore water samples are
to be taken is below the zone of incorporation.
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(2) The number of soil and soil-pore water samples to be
taken is based on the variability of:
(i) The leachate expected to leave the zone of incorporation;
and
(ii) The earth materials above the zone of saturation; and
(3) The frequency and timing of soil and soil-pore water
sampling is based on the frequency, time, and rate of waste
application, proximity to ground water, and soil permeability.
(d) The owner or operator must keep at the facility his
unsaturated zone monitoring plan, and the rationale used in
developing this plan.
(e) The owner or operator must analyze the soil and soil-pore
water samples and compare the results to the predictions required
under §§122.25(d) (2) and (3) and 122. 28(f).
6. Recordkeeping - §264.279
A. Proposed Regulations and Rationale
The regulations proposed in December 1978 included recordkeeping
and reporting requirements applicable to all treatment, storage,
and disposal facilities, including land treatment. The requirements
included: an operating log, a record of the quantity and description
of each waste received, locations in the facility where each waste
was treated or disposed and methods and dates of treatment or
disposal, the results of the waste analysis performed, monitoring
data, reports of visual inspections, and records of incidents
requiring initiation of a contingency plan.
The rationale for these requirements was presented in the
Part 265 Background Document dealing with the Manifest System,
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Record keeping, and Reporting requirements of the interim status
regulations.
B. Summary of Comments
Comments on the proposed recordkeeping and reporting
requirements are discussed in the Part 265 Background Document on
the Manifest System, Recordkeeping and Reporting.
C. Discussion
In structuring the Part 265 interim status regulations and
the Part 264 proposed regulations, Agency has elected to include
some of the proposed recordkeeping requirements of December 1978
in the sections of the regulations which address specific types of
facilities. Such recordkeeping is needed in Subpart N to allow
the owner or operator and the Regional Administrator to evaluate
compliance with specific requirements for land treatment.
For land treatment facilities, recordkeeping requirements have
been incorporated relative to the location where each different
waste is placed in the facility, when it was placed there, and at
what rate. This information will assist, through the use of mass-
balance analysis, in substantiating predictions made about leachate
migration through the unsaturated zone. The Agency believes that
these requirements are an integral part of facility operations.
These records may be needed to assist the owner or operator in
emergency situations or enforcement officials who may be called
upon to investigate problems. In most cases such recordkeeping
will be routinely performed to satisfy or supplement monitoring
and closure requirements.
The recordkeeping requirements for land treatment facilities
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are not expected to be burdensome since the types of waste and
treatment areas are typically limited at any one land treatment
facility.
Additional recordkeeping requirements relative to results
obtained from unsaturated zone monitoring, food-chain crop testing
or monitoring, and monitoring or analysis carried out under the
closure plan are specified elsewhere. The owner or operator is
required to place all such data and information in the operating
record of the facility. A discussion of the facility operating
record and the rationale for the inclusion of the data and
information specified is discussed in the Part 265 Background
Document on Manifest System, Hecordkeeping and Reporting.
D. Regulatory Language
The owner or operator of a land treatment facility must keep
records of the application dates, application rates, quantities,
and location of each hazardous waste placed in the facility, in
the operating record required in §264.73.
7. Closure and post-closure - §264.280
A. Proposed Regulations and Rationale
The proposed regulations provided two basic options for closure
of a land treatment facility. One option was to return the soil
in the treated area to its prexisting condition, as determined
by background soil analysis or analysis of similar local soils.
The other option was to remove the contaminated soil from the
facility if that soil met the characteristics of a hazardous waste.
(If it did not fail the hazardous waste characteristics, no further
action was required.) However, a variance to the second option
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permitted the facility to be closed as a landfill if the owner
or operator could demonstrate that the design or location provided
long-term integrity and environmental protection equivalent to a
landfill, as specified in the proposed regulations.
Che objective of the requirement to return the soil to its
preexisting condition or remove it, was to prevent the conversion
of huge tracts of productive land to land having limited potential
for future use. In addition, the Agency has limited data on the
fate and long-term effects of the hazardous contaminants in a land
treatment facility. There was concern that the contaminants would
eventually be carried away by surface runoff or would migrate to
ground water.
There was some precedent in state regulations for the proposed
approach. The Texas Department of Natural Resources incorporates a
similar approach in some of the permits issued for land treatment
facilities. If the results of tests comparing the leachate from
treated soil with untreated soil suggest a potential threat of
hazard to surface water, the Texas Department of Natural Resources
requires the removal of soil to a depth of 12 inches.
The variance for closure as a landfill was based on the
assumption that if appropriate liners, monitoring, and cover were
provided, the facility would not present a significant potential
for environmental damage. While this and the other closure options
take a conservative posture on closure, the Agency felt that it had
no information to suggest that other approaches would be protective
This is due to the fact that, to the knowledge of EPA, no hazardous
waste land treatment facility has been closed to date.
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B. Summary of Comments
(1) Return of soil to preexisting condition
0 Requiring return of soil to its original condition is
beyond RCRA authority. There is nothing in RCRA or its
legislative history to support this requirement.
0 Land treatment may improve some soils, so return to original
condition would be considered counterproductive.
0 Requiring that land be returned to its original condition
is unreasonable, impractical, and prohibitively expensive
and will eliminate land treatment.
0 The regulations should consider return to productive use,
i.e., capable of supporting indigenous vegetation.
0 The term "preexisting conditions" is vague and indefinite,
and the regulations fail to establish standards by which
the condition of the land upon closure may be established.
0 Return to original soil condition is unnecessary because
land treatment facilities can be returned to productive use
as long as levels of contaminants in the soil are not a
problem for those uses, and the amount of land used or
contemplated is not a significant portion of productive land
0 Requiring return of the soil to its preexisting condition
discriminates against industry, since land treatment of
POTW sludges has no such restrictions.
(2) Use of the Extraction Procedure* (EP) on soil
0 The EP may not appropriately identify contaminated soil .
It will underestimate the contamination of the soil, since
it does not test for all hazardous contaminants, only those
in the EPA Drinking Water Standards.
0 The decision to remove soil should include factors such
as: the chemical and physical characteristics of the
contaminants, the soil's ability to support vegetation,
the potential for erosion, the site location, and the
intended future use of the land.
0 The EP is not appropriate for clay soils, which often
contain cadmium and selenium in their natural state. Thus,
the EP may show virgin soil to be hazardous.
*The Extraction Procedure is described in §250.13(d) of Subpart A
in the December 19, 1978, proposed regulations.
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0 Should use water rather than the acid in the soil EP
because water is the "natural leachant" [sic] from
precipitation and runoff.
0 Naturally-occurring soils would fail the EP (data not
provided).
(3) Soil removal: closure as a landfill.
0 The potential expense of removal of soil or closure as a
landfill is extreme and would create a serious threat to
land treatment of industrial wastes.
0 To remove and landfill the soil in a land treatment facility
would so increase the overall cost of land treatment that
it would become economically noncompetitive with a landfill
or other disposal options. This would eliminate land
treatment as a disposal method. (No data provided.)
0 The removal of soil can result in problems of accelerated
erosion that would negate any questionable advantage of
removal.
(4) Suggested alternative closure requirements.
0 Soil should be allowed to remain only when soil erosion is
negligible for 50 to 100 years and an impermeable soil
structure exists.
0 Closure regulations should specify the objective of closure,
when it should begin, and certain minimum conditions.
Determination of when closure should begin should be based
on waste characteristics and soil properties, particularly
assimilation capacity. It is recommended that closure
regulations require:
closure so that no further maintenance is necessary
treating the soil to achieve a pH of 6.5 {minimum)
vegetative cover
control of erosion; maintenance of dikes
removal of any soil incapable of supporting vegetation or
which presents a threat to human health and the environment
0 Should consider specifying pH maintenance and other "onsite"
measures to prevent migration.
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0 Should require only soil monitoring for closure because
return to original condition is too difficult, and removal
would not eliminate the disposal problem. Additional
protection could be provided by the type of soil and the
berm around the treated area.
0 Should not look at the increase of contaminants in the
soil, but whether the soil presents a hazard to ground
water or whether crops grown on the soil would have
dangerously elevated concentrations.
0 Closure should relate to the level of potential environmental
harm.
0 Closure should require prevention of escape of metals by
runoff, plant uptake, or wind.
0 Should leave closure design criteria to the owner or
operator, since proper design is site-specific.
0 It is not true that, left unattended, contaminants of the
soil filter media will eventually be carried off by surface
runoff or will migrate to ground water. It is also not
true that such occurrences will be significant, especially if
plant cover is established. Under some conditions, soil
should be left as it is.
0 EPA's position for soil removal is inconsistent since EPA
admits no documented cases of ground-water contamination,
yet says that if soil is left unattended, contaminants
will eventually migrate.
C. Discussion
(1) Return of soil to preexisting condition.
The Agency agrees with may of the points made by commenters
and has removed this requirement from the final regulations. There
was a stong consensus in the comments that such a requirement was
impractical and would effectively terminate land treatment as a
waste management option. Furthermore, the Agency was unable to
identify methods of returning soil to its preexisting condition, or
to adequately define how the Agency would judge whether this has
been achieved. The Agency also concluded that this was not a
necessary condition for future productive use of the land. Finally,
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and most importantly, the Agency believes that alternative closure
requirements which are more practical can achieve protection of the
environment.
(2) Use of the Detraction Procedure (EP) on soil.
The proposed regulations referred to the extraction
procedure (EP), defined in Subpart A of the proposed regulations,
as the method to determine if soils in a land treatment facility
are hazardous at the time of closure. If the EP showed the soil to
be hazardous then the owner or operator was to close the site by
either removing the contaminated soil or closing the site as a
landfill.
Comments on the use of the EP suggested it was inappropriate,
but for diametrically opposite reasons. Some commenters felt the
EP would underestimate contamination because it covered only a few
contaminants, while other commenters felt the EP would overestimate
the contamination of the soil because it was too harsh an extractant.
Two commenters expressed concern that the EP would show certain
virgin soils to be hazardous. No data was provided to corroborate
the comments.
Based upon the comments and a reevaluation of its position,
the Agency found that the EP, as proposed in Subpart A, is not
appropriate as the sole indicator of whether the soil should be
removed or the facility should be closed like a landfill.
The Agency considered alternative soil tests, but was unable to
i
identify any which had both broad application and the ability to
unequivocally indicate that the soil of a land treatment facility is
contaminated to the extent it would need to be removed.
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The major drawback of using a simple soil test is that it does
not take into account the various extrinsic factors that play an
integral role in determining the hazard posed by the soil. This
point was made in the comments. One commenter suggested that the
decision to remove the soil of a land treatment facility should
include factors other than the EP results. The following factors
were identified: chemical and physical characteristics of the
contaminants, the soil's ability to support vegetation, the potential
to support vegetation, the potential for erosion, site location,
and intended future use of the land.
The Agency has decided to use an approach similar to the one
suggested in the comments. The Agency has identified four
environmental objectives and a number of factors that the owner or
operator of a land treatment facility should consider to meet the
objectives, when deciding on the disposition of the soil from the
active portion(s) of the site. A detailed discussion is presented
under item (4) below.
(3) Waste removal: closure as a landfill.
Although most of the closure comments focused on return of the
soil to its preexisting condition, a few comments addressed waste
removal and closure as a landfill. The tenor of these comments
was that these requirements would be too costly and would make land
treatment noncompetitive. No data were provided to support these
claims.
The Agency agrees that these proposed closure options will
result in increased costs for land treatment. However, the
contention that land treatment will become noncompetitive as a
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result of cost is not tenable. The cost of all waste management
practices will increase as a result of the Subtitle C regulations,
and the Agency expects land treatment to remain a viable waste
management option for certain waste streams. Additionally, it is
not the objective of the closure regulations to ensure that land
treatment remains competitive, in the economic sense. Rather, the
objective is to ensure that the closure requirements prevent the
uncontrollable release of contaminants into the environment.
The real issue is whether there is a need for such a restrictive
approach. Because of the dearth of information available on closing
land treatment facilities, and the relatively young age of this
waste managment practice, the Agency has not been able to
unequivocally demonstrate the need for such a restrictive and
rigid closure approach. As a result, the Agency has removed these
closure requirements from the final regulations in favor of a more
flexible approach, described below.
(4) Alternative closure approaches
A number of alternative closure approaches were suggested in
the comments. Many of these approaches may have merit in a given
situation. Most depend on a case-by-case assessment.
The Agency believes that it is both feasible and desirable to
base the closure requirements on such individual assessments. The
owner or operator should be allowed to make a case that a given
closure procedure will suit his particular situation and provide
adequate environmental protection. This type of approach is
necessary because of the current lack of experience with land
treatment facility closure and the consequent lack of a data base
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to adequately support particular closure requirements.
Therefore, the Agency has substantially revised the closure
requirements for land treatment facilities. The new requirements
specify that the owner or operator must develop and implement a
facility closure plan. The terms of that plan are enforceable
against the owner or operator. The plan must address four
objectives:
0 controlling the migration of leachate from the zone of
incorporation into ground water;
0 controlling the release of contaminated runoff to surface
water;
0 controlling the release of airborne particulate contaminants;
and
0 compliance with the standards established for food-chain
crops.
In meeting these objectives the owner or operator must consider
a range of factors affecting th facility's ability to meet the
objectives. Relative to ground-water protection, these factors
include: depth to ground water; ground-water use; geological profile;
amount and acidity of precipitation; type, concentration, and extent
of migration of leachate in the soil; expected rate of leachate
migration including any data from laboratory leaching studies
using the soil in the facility; soil characteristics, including
cation exchange capacity, total organic carbon, and pH; feasibility
of removing the contaminated soil at a later time if migration
continues and appears likely to contaminant ground water;
comprehensiveness of proposed monitoring following closure ; and
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proposed post-closure care, including maintenance of unsaturated
zone monitoring, restricting site access, and future land use.
Relative to surface water protection, the factors include:
surrounding geography and land use, surrounding surface water uses
and quality, amount and acidity of rainfall, use of cover or
vegetation to minimize erosion of contaminated soil, maintenance
of diversion structures to prevent surface runoff from entering
the active portion(s), structures for collecting and treating any
runoff , etc ..
Regarding wind erosion, the Regional Mmnistrator will evaluate
the use of vegetation or cover to prevent soil erosion and control
the release of airborne particulate contaminants.
The owner or operator must also develop a post-closure care
plan. The terms of this plan are also enforceable against the
owner or operator. Under these regulations the post-closure care
plan must provide for maintenance of monitoring systems, restriction
of access as appropriate for post-closure use, and control of the
growth of food-chain crops to the same degree as required for an
active facility.
D. Regulatory Language
(a) In the closure plan under §265.112 and the post-closure
plan under §265.118, the owner or operator must address the following
objectives and indicate how they will be achieved:
(1) Control of the migration of leachate from the zone of
incorporation into the ground water;
(2) Control of the release of contaminated run-off from the
facility into surface water;
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(3) Control of the release of airborne participate contaminants
caused by wind erosion; and
(4) Compliance with §264.276 concerning the growth of food-chain
crops.
(b) The owner or operator must consider at least the following
factors in addressing the closure and post-closure care objectives
of paragraph (a) of this Section:
(1) Type and amount of hazardous waste applied to the land
treatment facility;
(2) The mobility and the expected rate and amount of migration
of the leachate zone of incorporation;
(3) Site location, topography, and surrounding land use, with
respect to the potential effects of pollutant migration (e.g.,
proximity to ground water, surface water and drinking water sources);
(4) diversion structures to prevent surface water run-on from
entering the treated area; and
(5) Monitoring of soil, soil-pore water, and ground water.
(d) In addition to the requirements of §264.117,. during the
post-closure care period, the owner or operator of a land treatment
facility must:
(1) Maintain any unsaturated zone monitoring system, and
collect and analyze samples from this system in a manner and
frequency specified in the post-closure plan;
(2) Restrict access to the facility as appropriate for its
post-closure use; and
(3) Assure that growth of food chain crops complies with
§264.276.
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(e) For the purpose of complying with §264.115, when closure
is completed, the owner or operator of a land treatment facility
must submit to the Regional Administrator certification both by the
owner or operator and by a qualified engineer or by a qualified
soil scientist that the facility has been closed in accordance with
the specifications in the approved closure plan.
8. Special requirements for;
ignitable or reactive wastes - §264.281;
and incompatible wastes - §264.282
A. Proposed Regulations and Rationale
The proposed regulations prohibited placing ignitable, reactive,
volatile, and incompatible wastes in a land treatment facility,
but allowed a variance if the owner or operator can demonstrate
that airborne contaminants would not exceed a specified concentration,
and that the attenuation capacity of the facility would not be
adversely affected through heat generation, fires, or explosions.
The objective of the proposed regulation was to prevent damages
to human health and the environment which could result from fires
or explosions in a land treatment facility. Placing ignitable or
reactive wastes in a land treatment facility presents at least two
potential problems.
One problem is the contamination of the air through
volatilization, since most ignitable and some reactive wastes have
relatively high vapor pressures. A second problem is that ignitable
and reactive wastes can explode or burn easily, injuring the
personnel at the facility and releasing toxic fumes that can reach
surrounding populations and cause personal and property damage.
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Fires and explosions can also adversely affect the attentuation
capacity of the facility.
A recent study (3) has shown that, during land treatment
operations, fires and explosions can occur. Potential ignition
sources include electrical sparks from machinery operating on the
facility, accidents or errors such as smoking near the facility,
and extreme heat generation from reactive or incompatible sources.
Mixing of hazardous wastes that are not compatible with each
other in a hazardous waste land treatment facility can result in
similar types of environmental problems. Such mixing can cause
fires and explosions, excessive heat generation, or generation of
toxic gases. This could endanger facility personnel or populations
in the vicinity of the facility, or it could adversely affect the
attentuation capacity of the facility.
B. Summary of Comments
The restrictions on ignitable, reactive, and incompatible
wastes in the proposed regulations went beyond land treatment.
Similar restrictions were included in the proposed regulations for
all treatment and disposal facilities under §265.22, and standards
for basins under §250.45-5. The background documents dealing with
those standards contain additional analysis of comments on this
issue.
Those comments directed specifically toward land treatment
facilities are as follows:
0 The restriction on ignitables should be revised to allow
land treatment if the waste is no longer ignitable after
incorporation into the soil.
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0 Many hazardous wastes classified as ignitable or reactive,
or which are incompatible when combined, may lose these
properties when mixed with the soil due to dilution,
adsorption, or other mechanisms. Thus land treatment of
such wastes should not be prohibited.
0 A land treatment facility can act as a destruction mechanism,
rendering a waste nonhazardous through slow oxidation.
Ignitable, nitrated organics are particularly amenable to
slow oxidation in soils. This would be a safer disposal
method than rapid oxidation through incineration. The
hazard of most concern is placing the material without
incident during handling. An absolute prohibition against
land treatment of ignitables, reactives, or incompatibles
in any concentrations or quantities is inappropriate.
0 Land treatment is an attractive way to dispose of hazardous
oily wastes. The exclusion of land treatment of ignitables
should be lifted. This can be done safely with little or
no fire hazard.
0 The proposed regulations will preclude land treatment as a
viable alternative, since many wastes are ignitable, reactive,
or volatile, and corrosive wastes cannot be land treated
due to pH. The variance is not likely to be viewed favorably
by permit officials.
C. Discussion
Relevant to the discussion of the comments above is the fact
that the Agency is now planning to consider air emissions in the
permit issuance process. For discussion related to comments on
the variance in §250.45(c) dealing with volatility, the reader is
referred to the Background Document ND . 8 - Ground-water and Air
Bnission Monitoring.
The comments on ignitable waste suggest that incorporation of
such wastes into the soil is, in itself, an effective way of
rendering these wastes non-ignitable. The Agency concurs with this
suggestion. However, as a comment suggested, the safety of handling
the waste, i.e., incorporating it into the soil, is still an issue.
However, the Agency has no damage cases indicating that this has
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been a problem in practice up to this time. Nevertheless, one way
of eliminating or reducing this handling hazard would be to treat
or mix the waste prior to land treatment, so that the resulting
material is no longer ignitable. This practice would provide the
greatest margin of safety.
A similar logic would apply to land treatment of reactive or
incompatible wastes. In an attempt to find a method of rendering
such wastes nonreactive, the Army Material Development Command, at
Edgewood Aresenal in Natick, Massachusetts has safely land-treated
reactive wastes (30). While other characteristics of the particular
waste, (i.e., nonbiodegradability) , reduced the attractiveness of
land treatment, safe handling, and rendering the wastes non-reactive
did seem possible.
In view of these considerations, the regulations have been
revised to include conditions under which such wastes can be land
treated.
D. Regulatory Language
§265.281 Special requirements for ignitable or reactive waste
Ignitable or reactive wastes must not be land treated, unless:
(a) the waste is immediately incorporated into the soil so that
(1) the resulting waste, mixture, or dissolution of material no
longer meets the definition of ignitable or reactive waste under
§§261.21 or 261.23 of this chapter, and (2) §264.17(b) is complied
with; or
(b) The waste is managed in such a way that it is protected
from any material or conditions which may cause it to ignite or react.
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§265.282 Special requirements for incompatible wastes
Incompatible wastes, or incompatible wastes and materials,
(see Appendix V for examples) must not be placed in the same land
treatment area, unless §264.17(b) is complied with.
9. Special requirements for Classes of Facilities - §264.283
A. Proposed Regulations and Rationale
The proposed regulations required that the zone of incorporation
of a land treatment facility be a maximum of 1.5 meters above the
historical high water table. The land treatment facility could be
less than 1.5 meters if the owner or operator could demonstrate
that no direct contact would occur between the zone of incorporation
and the water table.
The purpose of this standard was to ensure that sufficient
distance exists between the zone of (waste) incorporaton and the
high water table. Direct contact between the zone of incorporation
and the water table for a prolonged period of time increases the
likelihood that wastes will escape to the environment. Direct
contact will preclude the existence of an unsaturated zone. The
process of attenuation, upon which a land treatment facility depends,
cannot function properly under saturated conditions.
An unsaturated zone is needed to provide space for unsaturated
zone monitoring and to compensate for fluctuations in the height of
the water table during its yearly hydrological cycle.
B. Summary of Comments
0 The 1.5 m requirement should be relaxed for land treatment
facilities located over non-underground drinking water
sources, e.g., salt or brackish ground water, otherwise
coastal areas of the U.S. will be out of consideration as
land treatment sites.
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0 Specification of 1.5 m is too specific for land treatment
disposal operations. Actual rules for a disposal site
should be based upon the geology and the material being land
treated.
0 A 1.5 m separation is inadequate from the standpoint of
protecting public health and the environment. Site
preparation and unforeseen site characteristics may encourage
vertical migration of contaminated soil water.
0 The utility industry had two opinions. Two commenters felt
the requirement was too stringent and would preclude
land farm ing of flyash and sludge in coastal areas. Another
commenter, although agreeing in principle with the other
two commenters, felt the variance to the regulation made it
acceptable, provided the Regional Administrator would
accept a showing based on readily-available historical
information as an adequate demonstration that no direct
contact will occur.
C . Discussion
Although this standard was not included in the Part 265 land
treatment interim status standards, it is included in Part 264.
The new standard requires a two meter .separation between the
incorporated waste and the aquifer being or to be used, (i.e., the
historical high water table for water table aquifers, or the bottom
of the confining soils for artesian aquifers).
This standard is considered necessary by the Agency because
of the nature of land treatment facilities, i.e., the reliance on
attenuation of contaminants in the unsaturated zone; and to ensure
that unsaturated zone monitoring can be achieved. The Agency
acknowledges that a land treatment facility might be able to operate
safely with less than two meters from a usable aquifer however the
basic purpose of technique (e.g., biological and chemical treatment)
would be interfered with, and that, along with the loss of the
capability to monitor performance by soil-pore (zone of aeration)
monitoring, does not warrant regulatory flexibility.
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D. Regulatory Language
A Class C, D, or E land treatment facility must have a minimum
of two meters between the incorporated waste and the aquifer being
or to be used, (i.e., the historical high water table for water
table aquifers, or the bottom of the confining soils for artesian
aquifer).
Ill . REFERENCES
1. U.S. Environmental Protection Agency. Report to Congress:
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2. Kincannon, C.B., Oily Waste Disposal by Soil Cultivation Process
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3. SCS Engineers. Land Cultivation of Industrial Wastes and
Municipal Solid Wastes: State of the Art Study. Volume 1.
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11. Bergh, A. K., and R. S. Peoples, Distribution of Polychlorinated
Biphenyls in a Municipal Wastewater Treatment Plan and Environs,
The Science of the Total Environment, 1977.
12. Personal communication with Dr. p. Kearney, USDA, Beltsville,
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13. Personal communication with Dr. A.M. Decker, University of
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30. Personal communication. George Marienthal, Department of
Defense, Washington, D.C., to L.A.Weiner, Office of Solid
Waste. October 19, 1977.
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