United States Solid Waste and EPA530-D-00-002
Environmental Protection Emergency Response September 2001
Agency (5305W) www.epa.gov/osw
Office of Solid Waste
v>EPA Guidance on Demonstrating
Compliance With the Land
Disposal Restrictions (LDR)
Alternative Soil Treatment
Standards
Interim Guidance
-------
Disclaimer
The United States Environmental Protection Agency's Office of Solid Waste (EPA or the
Agency) has prepared this document to provide interim guidance to EPA, the states, the public,
and the regulated community regarding how to measure attainment of the alternative LDR soil
treatment standards. Alternative approaches for planning and implementing a sampling
program and for assessing the data may be appropriate where waste or facility-specific
circumstances do not match the underlying assumptions, conditions, and models of the
guidance.
This guidance is not a final Agency action; it is intended solely as guidance. This guidance
does not amend or otherwise alter any promulgated regulation. This guidance is not intended
to and cannot be relied upon, to create any rights enforceable by any party in litigation with the
United States, or create any rights enforceable by the United States. EPA officials may decide
to follow the guidance provided in this document, or to act at variance with the guidance, based
on an analysis of specific site or facility circumstances. The Agency also reserves the right to
change this guidance at any time without public notice.
Interim Guidance -i- September 2001
-------
Table of Contents
1. INTRODUCTION AND BACKGROUND 1
1.1 What Is the Purpose of This Guidance? 1
1.2 What Are the LDR Alternative Soil Treatment Standards? 1
1.3 Why Did EPA Develop Alternative Soil Treatment Standards? 2
1.4 When Are Alternative Soil Treatment Standards Available in Authorized and
Unauthorized States? 2
1.5 When Do LDR Treatment Standards Apply to Hazardous Soils? 3
2. GUIDANCE FOR DETERMINING COMPLIANCE WITH THE ALTERNATIVE
TREATMENT STANDARDS FOR CONTAMINATED SOIL 4
2.1 What Steps Should I Use to Plan the Sampling and Analysis Program? 5
2.2 How Do I Implement the Sampling and Analysis Program? 11
2.3 How Should I Evaluate the Data to Determine Attainment of the Treatment
Standards? 12
2.3.1 What Simple Nonstatistical Method Can I Use to Evaluate Attainment
of the Soil Treatment Standards? 15
2.3.2 What Methods Can I Use to Determine Attainment of the UTS or
10 x UTS? 17
2.3.3 What Statistical Methods Can I Use to Determine Attainment of the
Alternative Soil Treatment Standard of 90-Percent Reduction? 18
2.3.3.1 A "Quick and Simple" Statistical Method for Determining
90-Percent Reduction 19
2.3.3.2 Welch's t-Test 21
2.3.3.3 Wilcoxon Rank-Sum Test 24
3. WHAT ARE THE NOTIFICATION, CERTIFICATION, AND RECORDKEEPING
REQUIREMENTS FOR CONTAMINATED SOILS? 27
References 28
APPENDIX A: "MANAGEMENT OF REMEDIATION WASTE UNDER RCRA"
APPENDIX B: STATISTICAL TABLES
Interim Guidance -N- September 2001
-------
List of Acronyms
AOC Area of Contamination
ASTM American Society for Testing and Materials
BTU British Thermal Unit
CFR Code of Federal Regulations
CM I Corrective Measures Investigation
DQA Data Quality Assessment
DQO Data Quality Objective
EPA Environmental Protection Agency
FR Federal Register
HSWA Hazardous and Solid Waste Amendments of 1984
LDRs Land Disposal Restrictions
mg/kg milligrams per kilogram
mg/L milligrams per Liter
QAPP Quality Assurance Project Plan
RCRA Resource Conservation and Recovery Act
RFI RCRA Facility Investigation
TC Toxicity Characteristic
TCLP Toxicity Characteristic Leaching Procedure
TSDF Treatment, Storage, or Disposal Facility
UHC Underlying Hazardous Constituent
USAGE United States Army Corps of Engineers
UTS Universal Treatment Standard
WAP Waste Analysis Plan
Interim Guidance
September 2001
-------
1. INTRODUCTION AND BACKGROUND
1.1 What Is the Purpose of This Guidance?
The purpose of this guidance is to provide suggestions and perspectives on how you, as
members of the regulated community, states, and the public, can demonstrate compliance with
the alternative treatment standards for contaminated soils that will be land disposed and,
therefore, will be subject to the RCRA land disposal restrictions (LDR) regulations. On May 26,
1998, EPA promulgated land disposal restriction treatment standards specific to contaminated
soils (see 63 FR 28555 and 40 CFR 268.49). Under these regulations, when disposing of
contaminated soils, you may elect to comply with either the alternative soil treatment standards
at 40 CFR 268.49 or the generic treatment standards at 40 CFR 268.40 which apply to all
hazardous wastes. The LDR alternative treatment standards require that contaminated soils
which will be land disposed must be treated to reduce concentrations of hazardous constituents
by 90 percent or meet hazardous constituent concentrations that are 10 times the universal
treatment standard (UTS), whichever is greater.
You should use this guidance only in connection with compliance with the LDR alternative
treatment standards that apply to contaminated soil which will be land disposed (e.g., soil
generated during a cleanup), and you should not use it to establish site-specific cleanup
standards.
This guidance document first describes the alternative treatment standards in some detail and
then explains why they were developed, and their implementation. It then presents step-by-
step guidance on approaches that can assist you in achieving compliance with the Agency's
alternative soil treatment standards.
1.2 What Are the LDR Alternative Soil Treatment Standards?
Under the LDR alternative soil treatment standards in 40 CFR 268.49(c)(1), there are two
approaches to achieving compliance:
hazardous constituents must be reduced by at least 90 percent through
treatment so that no more than 10 percent of their initial concentration remains
or comparable reductions in mobility for metals, OR
hazardous constituents must not exceed 10 times the universal treatment
standards (10 x UTS) at 40 CFR 268.48.
If you treat the soil to achieve the 90-percent reduction standard, or the treatment reduces
constituent concentrations to levels that achieve the standard of 10 x UTS, then further
treatment is not required.
Under 40 CFR 268.49(c), treatment for non-metals must achieve 90-percent reduction in total
constituent concentrations. Treatment for metals must achieve 90-percent reduction as
measured in leachate from the treated soil (testing according to the TCLP) when a metal
stabilization treatment technology is used, and as measured in total constituent concentrations
when a metal removal technology is used.
Interim Guidance 1 September 2001
-------
In addition to the treatment required by § 268.49(c)(1), under § 268.49(c)(2) prior to land
disposal, soils that exhibit the characteristic of ignitability, corrosivity, or reactivity must be
treated to eliminate these characteristics.
A hazardous constituent is a regulated constituent specified in the treatment standard at 40
CFR 268.40, or it may be an underlying hazardous constituent (UHC). Any constituent that is
listed in the UTS Table at § 268.48, except for fluoride, selenium, sulfides, vanadium, and zinc,
can be a UHC. You, as a facility owner or operator, may use knowledge of the waste to identify
those UHCs reasonably expected to be present when hazardous soils are generated. You
should use such a waste knowledge determination judiciously in identifying which UHCs are
reasonably expected to be present in a volume of soil. For more information on appropriate use
of knowledge of the waste, see EPA's Waste Analysis At Facilities That Generate, Treat, Store,
And Dispose Of Hazardous Wastes: A Guidance Manual, April 1994, available at
http://www.epa.gov/epaoswer/hazwaste/ldr/wap330.pdf. If you choose to use the soil treatment
standards, all UHCs present at levels greater than 10 x UTS must be treated regardless of
whether the soil contains a listed waste or exhibits a characteristic when the soil is generated.
A hazardous waste contaminated soil that is going to be used in products which are
subsequently used in a manner constituting disposal must meet the treatment standards
developed for as-generated industrial waste at 40 CFR 268.40.
1.3 Why Did EPA Develop Alternative Soil Treatment Standards?
The alternative soil treatment standards are designed to encourage more cost-effective cleanup
of hazardous contaminated soils subject to LDRs and to address the unique characteristics of
soils. Before these treatment standards were developed, soils subject to LDRs were required
to comply with traditional technology-based treatment standards developed for industrial
hazardous waste (see 40 CFR 268.40). Aside from potentially discouraging some
remediations, these treatment standards sometimes proved to be inappropriate (e.g.,
impracticable or not cost-effective) or unachievable (e.g., did not account for heterogeneous
soil matrices) when applied to hazardous constituents present in soils. The soil treatment
standards at 40 CFR 268.49 continue to minimize threats to human health and the environment
(as required by RCRA section 3004(m)), but provide for more flexible treatment requirements
that consider the unique characteristics of soils and applicable treatment technologies, and can
be achieved by using non-combustion treatment technologies.
1.4 When Are Alternative Soil Treatment Standards Available in Authorized and
Unauthorized States?
Like all LDR treatment standards, the soil treatment standards are promulgated pursuant to the
Hazardous and Solid Waste Amendments of 1984 (HSWA). Because the alternative soil
treatment standards are generally less stringent than current federal requirements for soils,
they would not be available in states authorized for the land ban until the state had adopted
them.
EPA encourages states to implement the revised soil standards as rapidly as possible. If a
state - through implementation of State waiver authorities or other State laws - were to allow
compliance with the soil treatment standards in advance of adoption or authorization, EPA
Interim Guidance 2 September 2001
-------
generally would not consider such application of the soil treatment standards for purposes of
enforcement or State authorization. Thus, by using State law to waive authorized or non-
authorized State requirements, a State can allow immediate implementation of the soil
treatment standards without jeopardizing its RCRA authorization. (See EPA guidance
memorandum from Elizabeth A. Cotsworth to RCRA Senior Policy Advisors, Regions I - X,
"Phase IV Land Disposal Restrictions Rule - Clarification Of Effective Dates" October 19, 1998
at: http://www.epa.gov/epaoswer/hazwaste/ldr/ldrmetal/memos/effectiv.pdf, especially page 13).
To date, according to EPA records, 29 states have adopted the LDR Phase IV rule, and five of
these have received authorization (see
http://www.epa.gov/epaoswer/hazwaste/state/charts/chart1.pdf). Because the availability of the
soil treatment standards will vary from state to state, EPA recommends that you contact your
state regulatory agency if you have any questions.
1.5 When Do LDR Treatment Standards Apply to Hazardous Soils?
LDR treatment standards apply to hazardous soils that are "generated" and managed in a
manner that qualifies as "placement" on the land for the purposes of the Land Disposal
Restriction Program. Soils to which the standards apply are those soils that: (1) are removed
from the area of contamination (i.e., "generated"); (2) are a hazardous waste (either because
they contain a listed hazardous waste or because they exhibit a hazardous waste
characteristic); (3) are prohibited from land disposal (e.g., because they do not meet the
applicable LDR treatment standard(s) and they are not eligible for a variance, extension, or
exemption); and (4) are destined for land disposal.
Whether a soil is both generated and managed in a unit that qualifies as placement is
dependent on a number of factors. For example, if hazardous soil is consolidated within an
area of contamination, it would not be considered generated under the LDR program. If the soil
is removed from the area, it is considered to be generated for the purposes of LDRs, and it may
not be managed in a manner that qualifies as placement without prior treatment. For more
specific information about when LDR treatment standards apply to the soil due to placement on
the land, see the Phase IV Land Disposal Restrictions (63 FR 28556, May 26, 1998, especially
pages 28617 through 28620). See also the memo entitled "Management of Remediation
Waste Under RCRA" (EPA/530-F-98-026, Office of Solid Waste and Emergency Response),
which can be found in Appendix A of this document.
Interim Guidance 3 September 2001
-------
2. GUIDANCE FOR DETERMINING COMPLIANCE WITH THE ALTERNATIVE
TREATMENT STANDARDS FOR CONTAMINATED SOIL
If LDR treatment standards apply to your soil, or if you think the standards will apply (for
example, because hazardous soils will be excavated as part of the remedy), then you can use
the guidance in this section to help determine how to comply with the standards.
The generator of the hazardous soil must determine if the soil has to be treated before it can be
land disposed (§ 268.7(a)(1)). This can be done by using waste knowledge, by sampling and
analysis, or by a combination of waste knowledge and sampling and laboratory analysis. If
using the waste knowledge approach(es), you can show acceptable knowledge by using:
process knowledge, or detailed information on the wastes obtained from existing
published or documented waste analysis data or studies conducted on
hazardous wastes generated by similar processes;
waste analysis data obtained from facilities which send wastes off-site for
treatment, storage, or disposal (e.g., generators); or
facility records, which must be current and accurate, of analyses performed
before the effective data of RCRA regulations.
The waste knowledge approach(es) may be particularly useful if hazardous constituents in
wastes from specific processes are well documented or if discarded wastes are unused
commercial chemical products or reagents with known physical or chemical constituents. Also,
you may choose to use waste knowledge if conditions are not conducive to sampling and
analysis due to health and safety risks or the physical nature of the actual wastes. If you
choose to use waste knowledge or a combination of waste knowledge and sampling and
analysis, documentation is essential to demonstrate that the information used identifies the
waste accurately and completely.
Treatment facilities (under § 268.7(b)) and land disposal facilities (under § 268.7(c)(2) must test
their waste according to the frequency specified in their waste analysis plans as required by 40
CFR 264.13 (for permitted TSDs) or 40 CFR 265.13 (for interim status facilities).
For more information on appropriate use of waste knowledge and sampling and analysis, see
EPA's Waste Analysis At Facilities That Generate, Treat, Store, And Dispose Of Hazardous
Wastes: A Guidance Manual, April 1994, available at
http://www.epa.gov/epaoswer/hazwaste/ldr/wap330.pdf
You should determine as early as possible in the site characterization process whether LDRs
might apply to your soils. To do this, you will need to integrate site characterization, hazardous
waste determination, and LDR compliance activities early in the corrective action. If you
anticipate that generation of hazardous soils will occur and that those soils will be subject to
LDRs due to land placement, then you could plan to generate site characterization data that
also meet the performance and acceptance criteria for LDR compliance. This strategy could
minimize redundant waste analyses, reduce costs, and save time.
Interim Guidance 4 September 2001
-------
As discussed earlier in Section 1.2, the alternative soil treatment standard under 40 CFR
268.49(c)(1) includes treatment of soil to one of two standards, whichever is higher:
hazardous constituents must be reduced by at least 90-percent through
treatment, OR
hazardous constituents must not exceed 10 x UTS at 40 CFR 268.48.
The data collection and assessment methods needed to demonstrate attainment of the 90-
percent reduction standard will differ from those needed to demonstrate attainment of 10 x
UTS. Specifically, if you plan to use sampling and analysis to determine compliance with the
90-percent reduction standard, then you may need to obtain TWO sets of samples as part of
the sampling strategy:
Obtain one set of samples prior to treatment to estimate concentrations of
contaminants of concern in the soil for comparison to LDR standards and to
determine if treatment is needed, AND
If treatment is needed, obtain another set of samples after treatment to estimate
concentrations of contaminants of concern in the same volume of soil and to
determine if the treatment has attained the standard.
If you elect to use the UTS or 10 x UTS (rather than 90-percent reduction), then it will not be
necessary to obtain an initial set of samples from the untreated soil for comparison to the
samples obtained from the treated soil.
Prior to conducting any sampling or data collection activities, we suggest you use a systematic
planning process such as EPA's Data Quality Objectives (DQO) process, followed by
development of a quality assurance project plan (QAPP) and waste analysis plan (WAP).1
2.1 What Steps Should I Use to Plan the Sampling and Analysis Program?
We recommend that you use the Data Quality Objectives (DQO) process (Figure 1) or a similar
systematic planning process to help develop a sampling strategy to characterize the
contaminant concentrations within the soil. The DQO process is a systematic data collection
planning process developed by EPA to ensure that the right type, quality, and quantity of data
are collected to support decision making.
You can find detailed guidance on the DQO process in Data Quality Objectives
Process for Hazardous Waste Site Investigations, EPA QA/G-4HW (\JSEPA 2000a) and the
Guidance for the Data Quality Objectives Process, EPA QA/G-4 (USEPA 1994a).
To help you get started, you can use the following seven-step DQO process to plan a sampling
1 For treatment, storage, or disposal facilities (TSDFs), the sampling and analysis procedures typically are
documented in a waste analysis plan (WAP). For RCRA corrective actions or Superfund remedies, sampling and
analysis procedures may be described in any of a number of planning documents (e.g., RFI Work Plan, CMI Work
Plan, Remedial Action Plan, etc.) which we refer to generically as the quality assurance project plan (QAPP).
Interim Guidance 5 September 2001
-------
State the Problem
Identify the Decision
Identify Inputs to the Decision
Define the Study Boundaries
Develop a Decision Rule
Specify Limits on Decision Errors
Optimize the Design for Obtaining Data
program to demonstrate compliance with
the alternative soil treatment standards.
Based on these general steps, you
should develop detailed DQO outputs for
your specific project.
Step 1: State the Problem - The
outputs of this step will include a list of
members of the planning team, the
resources available, the schedule, and a
concise description of the problem. For
the purpose of a 90-percent reduction or
10 x UTS attainment determination, the
"problem" is to identify those soils that
attain the 90-percent reduction standard
or that have concentrations less than 10
xUTS.
Step 2: Identify the Decision - The
decision is to determine whether the
concentrations of contaminants of
concern in a given volume of soil after
treatment have been reduced by at least
90 percent from the concentrations prior
to treatment or whether they have
concentrations less than 10 x UTS. If
either condition has been satisfied, then the treatment standard has been attained. If not, then
the soils must be re-treated or an alternative waste management option must be found.
Step 3: Identify Inputs to the Decision - This step of the DQO process requires a list of
informational inputs needed to resolve the decision statement. For the purpose of complying
with the alternative soil treatment standards, these inputs would include, at a minimum, a list of
the underlying hazardous constituents, the units of measure (e.g., mg/kg or mg/L), and a listing
of appropriate analytical methods, method performance criteria (e.g., for precision and
accuracy), and required quantitation limits. If you elect to use 10 x UTS as the treatment
standard, then the analytical methods must be capable of detecting constituents of concern at
concentrations less than 10 x UTS. Data of sufficient quality to measure attainment of 10 x
UTS also should be adequate to measure attainment of the 90-percent reduction standard.
Note that under 40 CFR 268.49(c), treatment for non-metals must achieve 90-percent reduction
in total constituent concentrations. Treatment for metals must achieve 90-percent reduction as
measured in leachate from the treated soil (testing according to the TCLP) when a metal
stabilization treatment technology is used, and as measured in total constituent concentrations
when a metal removal technology is used.
Step 4: Define the Boundaries - Under 40 CFR 268.49(d), the treatment standards apply to
"any given volume of contaminated soil" that meets the definition of a hazardous waste when
generated (e.g., is a hazardous waste upon excavation), does not already meet applicable LDR
Figure 1. The Seven Steps in the DQO Process (from USEPA
1994a).
Interim Guidance
September 2001
-------
treatment requirements, AND will be land disposed. The decision to generate a hazardous soil
usually will be made within a risk-based corrective action decision-making context.2 For
additional information regarding hazardous soil generation, see the memo in Appendix A of this
document, entitled "Management of Remediation Waste Under RCRA" (EPA/530-F-98-026,
Office of Solid Waste and Emergency Response).
If the remedy involves excavation of soil, you must determine whether the soil or identifiable
portions of that soil (i.e., "any given volume") are subject to the LDRs. In practice, site
characterization data or waste knowledge may allow you to determine a priori which soils will be
subject to LDRs upon excavation. The volume of soil subject to LDRs could be defined as:
single volumes of soil (e.g., soil contained in a drum),
manageable subsets, strata, or units of soil with distinct characteristics (e.g.,
cleanup units consisting of 1/4-acre lots at 6-inch intervals), or
one or more "hot spots" (that is, localized areas of high contamination).3
You, as the generator, should determine the physical size of each "given volume" of soil on a
site-specific basis. Note that each volume of hazardous soil that will be treated using the
alternative standards does not necessarily need to remain segregated from other similarly
classified hazardous soil for the purpose of treatment. If a given volume of soil is a mixture of
hazardous soils from different locations at a site, then the entire mixed volume must be treated
to meet the applicable standard.
Generally, subject to some limited exceptions, you should not mix hazardous soil (e.g., soil that
exhibits the TC) with nonhazardous soils prior to treatment. To do so may be impermissible
dilution. For example, once a hazardous contaminated soil has been generated and becomes
subject to LDR treatment standards, dilution of that soil solely as a substitute for adequate
treatment to achieve compliance with LDR treatment standards is considered impermissible
dilution and is prohibited under 40 CFR 268.3.4 However, there are exceptions:
(1) If mixing occurs through the normal consolidation of contaminated soil from various
portions of a site that typically occurs during the course of remedial activities or in the
course of normal earthmoving and grading activities, then the Agency does not consider
this to be intentional mixing of soil with nonhazardous soil for the purposes of evading
LDR treatment standards. Therefore, it is not viewed as a form of impermissible
dilution. See 63 FR 28605 and 28621 (May 26, 1998). Indeed, if a contaminated soil is
2 Note that the treatment standards do not apply to in situ soils, nor do they force soils to be excavated. If
contaminated soil is managed within an area of contamination (AOC) and is being treated in situ or consolidated
within an AOC, then the LDR treatment requirements do not apply.
3 For guidance on how to identify "hot spots," see Gilbert (1987, page 119), USEPA(1989), and the
ELIPGRID software (Davidson 1995).
4 In addition, per 40 CFR 268.2(k) hazardous waste may not be deliberately mixed with soil solely to
change its treatment classification from waste to soil.
Interim Guidance 7 September 2001
-------
consolidated within an area of contamination before it is removed from the land (i.e.,
generated), the determination as to whether the soil exhibits a characteristic of
hazardous waste may be made after such consolidation. If the soil is determined not to
be hazardous when removed, neither Subtitle C nor the land disposal restriction
requirements would apply.
(2) Some situations may require soil mixing, as part of a pre-treatment process, to facilitate
and ensure proper operation of the final treatment technology to meet the LDR
treatment standards. If the mixing or other pre-treatment is necessary to facilitate
proper treatment in meeting the LDR standards, then dilution is permissible. For
example, addition of less contaminated soil may be needed to adjust the contaminated
soil BTU value, water content, or other properties to facilitate treatment. These
adjustments would be for meeting the energy or other technical requirements of the
treatment unit to ensure its proper operation. The Agency views this type of pre-
treatment step as allowable, provided the added reagents or other materials produce
chemical or physical changes and do not (1) merely dilute the hazardous constituents
into a larger volume of waste so as to lower the constituent concentration or (2) release
excessive amounts of hazardous constituents to the air. See 51 FR 40592 (November
7, 1986) and 53 FR 30911 (August 16, 1988).
In practice, it will not be possible to ensure that all portions of soil submitted for treatment have
concentrations greater than 10 x UTS. Thus, you should have sufficient data or waste
knowledge to indicate that a large proportion of the soil in a given volume has concentrations
greater than 10 x UTS for one or more of the UHCs of interest. You will need to use educated
judgment to avoid unnecessary treatment.
If you plan to determine the volume of soil subject to the treatment standard prior to excavation
(i.e., in situ soils), then you could delineate the soils using a spatial analysis (for example, by
using geostatistical techniques). For assistance with application of geostatistical methods,
consult a professional geostatistician or see Myers (1997), Isaaks and Srivastava (1989),
Journel (1988), USAGE (1997), and USEPA (1991a).
If you plan to determine the volume of soil subject to the treatment standard when the soil is
excavated (i.e., at the point of generation) and placed in temporary piles, or stored (e.g., in
drums or roll-off boxes), then the piles, drums, and/or roll-off boxes could define the
boundaries.
Note that if the 90-percent reduction standard is used, then the estimate of post-treatment
concentrations should apply to the same unit of soil characterized initially. This strategy
ensures consistent comparison of the soil before and after treatment. One approach is to track
each batch of soil through the characterization and treatment process. As an alternative, you
could conduct an initial study to demonstrate that the treatment process achieves at least 90-
percent reduction. For subsequent treatment of the same type of contaminated soil, you should
monitor the treatment process variables, controls, and operating conditions and establish waste
and/or process knowledge, in lieu of testing, to support your claim that the standard has been
achieved. For long-term treatment projects, you should retest periodically to confirm that the
standard continues to be achieved. This strategy offers increased flexibility to operators and
could reduce overall costs for sampling and analysis.
Interim Guidance 8 September 2001
-------
Hypothetical example of defining a "given volume" of contaminated soil subject to LDRs:
During a construction project at an active refinery, the facility identified soil contaminated with benzene.
A risk-based cleanup level of 1.5 mg/kg was established for the site, and a decision was made to
excavate all soil with concentrations exceeding the cleanup level. The UTS for benzene for
nonwastewaters is 10 mg/kg.
The site characterization determined that the contaminated soil was confined to a horizontal area 40 feet
wide by 90 feet long. The depth of contamination was approximately six feet. To characterize the site,
the soils were divided into a series of10ftx10ftx3ft "blocks" so that a remedial decision could be
made for each block. Using this approach, each block of contaminated soil was placed into one of three
categories for subsequent removal, treatment, and disposal:
1. Nonhazardous soils. Nonhazardous soils were those soils with TCLP concentrations less than
0.5 ppm but with total concentrations exceeding the risk-based cleanup level of 1.5 mg/kg. The
facility identified 52 "blocks" or approximately 578 cubic yards of soil in this category. The LDR
treatment standards do not apply to these soils, and the soils will be treated and disposed in
accordance with the state's risk-based corrective action program.
2. TC hazardous soils with total concentrations less than 10 x UTS. These soils exhibited the
TC for benzene but had total benzene concentrations less than 10 x UTS (i.e., less than 100
mg/kg). The facility identified six "blocks" or approximately 67 cubic yards of soil in this
category. Upon removal, the facility considered the soil to meet the alternative soil treatment
standard of 10 x UTS and determined that the soil could be disposed as hazardous waste
without further treatment.
3. TC hazardous soils with total concentrations greater than 10 x UTS. These soils exhibited
the TC for benzene and had total benzene concentrations greater than 10 x UTS (i.e., greater
than 100 mg/kg). The facility identified 14 "blocks" or approximately 155 cubic yards of soil in
this category. This volume of soil (155 cubic yards) was designated as the "given volume" to
which, upon generation, the facility elected to apply the alternative soil treatment standards at 40
CFR 268.49 (10 x UTS or 90% reduction).
Step 5: Develop a Decision Rule - In this step, you specify the parameter of interest, specify
an action level, and develop a decision rule. A "parameter" is a descriptive measure of a
population such as the population mean (or average), median, or some percentile (such as the
99th percentile). An action level is a concentration limit that would cause you to choose between
alternative actions.
If you elect to apply the 90-percent reduction standard, then the parameter of interest is the
difference in the mean concentrations "before" treatment and "after" treatment. The action level
is implicitly defined as the mean concentration in the untreated soil.
If you elect to use 10 x UTS as the action level, then the parameter of interest is the maximum
(i.e., no sample analysis result can exceed 10 x UTS). Note that the standard of 10 x UTS is
more practicable when there is relatively low variability in constituent concentrations in the
treated soil and average concentrations are well below their applicable standards (see also
Section 2.3.2).
Interim Guidance 9 September 2001
-------
The decision rule for contaminated soils subject to the alternative soil treatment standards is:
If treatment of the contaminated soil has achieved on average at least 90
percent reduction in constituent concentrations, or maximum concentrations do
not exceed 10 x UTS, then the alternative treatment standard for contaminated
soil has been attained.
Step 6: Specify Limits on Decision Errors - You will use the sample analysis results to
support a decision about whether a given volume of soil attains the standard. Because of
variability in contaminant concentrations within a given volume of soil, practical constraints on
the number of samples that can be obtained and analyzed, and random variability and biases
that can be introduced in the sampling and measurement processes, the data collected may not
be representative and may mislead the decision maker into making an incorrect decision. A
decision error occurs when sampling data mislead the decision maker into choosing a course of
action that is different from or less desirable than the course of action that would have been
chosen with perfect information (i.e., with no constraints on sample size and no measurement
error).
We recognize that data obtained from sampling and analysis are never perfectly representative
and accurate, and that the costs of trying to achieve near-perfect results can outweigh the
benefits. Uncertainty in data must be tolerated to some degree. The DQO process controls the
degree to which uncertainty in data affect the outcomes of decisions that are based on those
data. This step of the DQO process allows the decision maker to set limits on the probabilities
of making an incorrect decision.
Hypothesis tests can be used to control decision errors. When performing a hypothesis test, a
presumed or baseline condition, referred to as the "null hypothesis" (H0 ), is established. This
baseline condition is presumed to be true unless the data conclusively demonstrate otherwise,
which is called "rejecting the null hypothesis" in favor of an alternative hypothesis (Ha). For the
purpose of determining compliance with the 90-percent reduction alternative soil treatment
standard, the baseline condition, or H0, is that the given volume of soil does not attain the
standard. Using the statistical notation for hypothesis testing5, these hypotheses can be stated
as follows:
- ^Treated ~ °-l/* Untreated > °
/^Treated ~~ ^M Untreated ^
When the hypothesis test is performed, two possible decision errors may occur:
1 . Deciding the soil treatment achieves 90-percent reduction, when the correct
decision (with complete and perfect information) would be "the soil treatment
does not achieve 90-percent reduction," or
5 The symbol"//' is used to represent the population arithmetic mean. The mean is the best parameter for
determining 90-percent reduction. Where normality assumptions are grossly violated, however, another central
tendency estimator such as the median may be used instead. For more information, see "Checking Data for
Normality" in Section 2.3.3.
Interim Guidance 10 September2001
-------
2. Deciding the soil treatment does not achieve 90-percent reduction, when the
correct decision would be that the treatment does in fact achieve 90-percent
reduction.
Because the soil is known to be contaminated and known to have concentrations greater than
10 x UTS, we can presume (as a "null hypothesis") that the soil does not attain the standard.
The sampling data must provide clear evidence that the soil treatment achieves 90-percent
reduction or that the concentrations are less than 10 x UTS; otherwise, we must presume that
the soil treatment standard has not been achieved. This presumption provides the basis for
classifying the two types of decision errors. To decide that the soil treatment achieves the
standard, when in fact it does not, is designated as a Type I decision error (also known as a
"false rejection" of the null hypothesis). To decide that the soil treatment does not achieve the
standard, when in fact it does, is designated as a Type II decision error (also known as a "false
acceptance" of the null hypothesis). The probability of making a Type I error is denoted by
a ("alpha").6
We recommend you set the Type I error rate, a , equal to 0.10. Setting the error rate at this
level will ensure there is only a 10% chance of falsely rejecting the null hypothesis. In other
words, when the standard has not truly been met, the test will erroneously conclude it has been
achieved only one time in 10.
Step 7: Optimize the Design for Obtaining the Data - The objective of this step is to
develop a sampling and analysis plan that obtains the requisite information from the samples
for the lowest cost and still satisfies the DQOs. You can find detailed guidance on the
development and optimization of a sampling plan in the following references: ASTM (1998a),
Mason (1992), Myers (1997), and USEPA (2000b).
2.2 How Do I Implement the Sampling and Analysis Program?
To implement the sampling and analysis program, you should develop and follow a project-
specific QAPP or WAP. Guidance for developing a QAPP can be found in EPA Guidance For
Quality Assurance Project Plans, EPA QA/G-5 (USEPA 1998b). Guidance for developing a
WAP can be found in Waste Analysis at Facilities That Generate, Treat, Store, and Dispose of
Hazardous Wastes, a Guidance Manual (USEPA 1994b) available at:
http://www.epa.gov/epaoswer/hazwaste/ldr/wap330.pdf
Detailed guidance on implementing a field sampling program to characterize soil can be found
in Preparation of Soil Sampling Protocols: Sampling Techniques and Strategies, EPA/600/R-
92/128 (Mason 1992), and in a variety of other publications including ASTM (1995, 1998b,
1998c, 1999), Myers (1997), and USEPA (1991b).
6 It also is possible to specify a Type II error rate (P), however, specification of the Type II error rate is not
required to perform the statistical tests described in this guidance. Additional guidance on decision errors can be
found in EPA's "G-4" and "G-9" guidance documents (USEPA 1994a and 1998c).
Interim Guidance 11 September 2001
-------
2.3 How Should I Evaluate the Data to Determine Attainment of the Treatment
Standards?
You should perform two data assessment activities to evaluate your sample analysis results:
(1) data verification and validation and (2) data quality assessment. Perform data verification
and validation in accordance with procedures specified in the QAPP or WAP to ensure that the
sampling and analysis protocols specified in the planning documents were followed and that the
measurement systems performed in accordance with the specified criteria.
Following data verification and validation, you should perform data quality assessment (DQA).
DQA is the scientific and statistical evaluation of data to determine if the data are of the right
type, quality, and quantity to support their intended purpose. You can find detailed guidance on
DQA in EPA's Guidance for Data Quality Assessment, EPA QA/G-9 (USEPA 1998c).
As one of the final activities in the DQA process, you should evaluate the data to determine
whether or not you have attained the alternative treatment standards. You can select the
appropriate method for data evaluation based on the type of treatment standard being used and
other site-specific conditions (such as the volume of soil subject to the treatment standards and
the physical characteristics of the soil).
Figure 2 provides a generalized flow diagram indicating the decision-making process for
determining attainment of the alternative soil treatment standards.
Table 1 provides an overview of the various data evaluation methods available for determining
attainment of the alternative soil treatment standards along with their appropriate conditions for
use, advantages, and limitations. Note that the statistical methods included here are provided
as guidance only. In those cases where you require additional information or more advanced
statistical methods, we suggest you seek assistance from a statistician.
Section 2.3.1 describes a simple nonstatistical method that can be used when only a small
volume of soil is in question or when relatively small individual "batches" of soil are subject to
treatment. Section 2.3.2 describes methods that can be used to evaluate attainment of the
UTS or 10 x UTS. Section 2.3.3 describes statistical methods that can be used to evaluate
attainment of the 90-percent reduction standard.
Interim Guidance 12 September 2001
-------
Define the "given volume of soil" subject to LDRs
per 268.49(a)(use DQO Process Step 4).
If the 90% reduction standard is selected, then obtain
nu random samples representing the untreated soil.
Treat the soil to achieve 90% reduction or 10 x UTS
Does the
soil attain the
standard of
10xUTS?
Obtain nT random samples representing the treated
soil.
Select a data evaluation method and perform
evaluation of data (see Table 1 in Section 2.3).
Soil does not attain
the standard.
nu = number of samples representing the untreated soil
n-f = number of samples representing the treated soil
Figure 2. Flow chart for determining attainment of the alternative soil treatment standards.
Interim Guidance 13
Yes
Does the data
evaluation indicate
that 90% reduction
is achieved?
Does the soil
attain the standard of
< 10 x UTS?
Son attains the standard
September 2001
-------
Table 1. Summary of Data Evaluation Methods
Data Evaluation
Method
Type of Standard
90%
Reduction
10 x
UTS
Guidance
Section
No.
Appropriate Conditions for Use
Advantages
Limitations
Nonstatistical Method
2.3.1 Useful when soil is relatively
homogeneous, sampling and
measurement error can be minimized,
or the volume of soil is relatively small
Useful when only a rough estimate of
the constituent concentration is
required
Simple
Easy to use and understand
Low-cost
Only provides a "point estimate" of the
constituent concentration
Does not provide information about
variability
Does not quantify the uncertainty
associated with the estimate
Simple Exceedance
Rule
2.3.2
Analytical detection limit must be less
than the treatment standard.
Simple, easy to use and understand
Easy to enforce
Data set can include nondetects.
Requires a large number of samples
to provide high confidence that the
standard is achieved
Tolerance Limit
2.3.2 Most useful when the analytical
detection limit is well below the
treatment standard and sampling and
measurement error are minimal
Data must exhibit an approximately
normal distribution.
A small number of samples can be
used (we recommend at least four
random samples).
Relatively easy to calculate
The calculated limit will be very
sensitive to the size of the standard
deviation relative to the mean.
Nonparametric Test
of Location
2.3.3.1
Useful if there are no extreme values
in the data sets
Quick
Simple
Easy to use
Does not require the assumption that
the data exhibit a normal distribution.
Can be used with data sets that
include "nondetects"
Provides less statistical "power" than
Welch's t-Test or the Wilcoxon Rank-
Sum test (i.e., the test may indicate
that 90-percent reduction has not
been achieved, when in fact it has)
Welch's t-Test
2.3.3.2
Data must exhibit an approximately
normal distribution.
Provides more statistical "power" than
the test of location if the underlying
assumptions for the test are satisfied
Cannot be used when a large
percentage (>20%) of the data are
reported as nondetect
Requires more statistical calculations
than other methods (e.g., calculation
of the mean, variance, and degrees of
freedom)
Wilcoxon Rank-Sum /
Test
2.3.3.3 Useful when the underlying
distribution of the data is unknown or
cannot be readily identified
Useful when a significant percentage
(>20%) of the data are reported as
nondetect
Easy to compute and understand
Can be used with data sets that
include "nondetects"
Provides less statistical "power" than
Welch's t-Test if the data follow a
normal distribution or are
approximately symmetrical
/ = appropriate for use.
X = not appropriate for use.
Interim Guidance
14
September 2001
-------
2.3.1 What Simple Nonstatistical Method Can I Use to Evaluate Attainment of the Soil
Treatment Standards?
As part of the planning process, the planning team must define the volume of soil that needs to
be characterized for the purpose of evaluating attainment of alternative soil treatment
standards. If the "given volume" (as specified at 40 CFR 268.49(d)) is relatively small, the soil
is relatively homogeneous, or the sampling and measurement error can be minimized, then a
single sample may be adequate to estimate the concentration in the volume of soil, and use of
a statistical method to determine attainment of soil treatment standards may not be necessary
or appropriate.7
As a practical matter, the volume of soil characterized using this nonstatistical method could be
defined operationally, such as: (1) the volume of soil that will fit in a 55-gallon drum, (2) some
reasonably small volume that could be excavated by a backhoe during remedial activities (such
as a 10 ft-by-10 ft-by 2 ft block of soil), or (3) small volumes of soil that are considered
"batches" in a batch treatment process.
This approach can be used to evaluate attainment of either the 90-percent reduction standard
or the standard of 10 x UTS. If the 90-percent reduction standard is used, then a sample must
be obtained and analyzed before treatment of the given volume and a second sample obtained
from the same unit of soil and analyzed after treatment. Only those two data points would be
used to determine 90-percent reduction. Using this nonstatistical approach, the decision rule to
determine compliance with the 90-percent reduction standard is simple: the concentration (C)
of the constituent of concern in the sample of the treated soil must be less than or equal to 1/10
of the concentration found in the sample of the untreated soil.
c
^treated ~ ^'^^ untreated )
One of the key underlying assumptions of this approach is that a single soil sample can provide
an adequate estimate of the concentration within a given volume of soil. If the soil is
heterogeneous, then a single soil sample (such as a core a few centimeters in diameter) may
not provide a good estimate of the mean concentration within the given volume of soil.
The nonstatistical procedure for evaluating attainment of the 90-percent reduction standard is
performed as follows:
Step 1. Define a small "given volume" of soil to be characterized and treated (see DQO
process Step 4).
Step 2. Obtain a sample from the given volume and submit the sample for laboratory
analysis.
7 Sampling error can be minimized by using an optimal sample mass, obtaining the correct shape and
orientation of individual samples (known as the sample "support"), and by using sampling devices and sub-sampling
procedures that will minimize biases. For detailed guidance on controlling error in sampling, see Mason (1992) and
Myers (1997).
Interim Guidance 15 September2001
-------
Step 3. After treatment of the given volume of soil, obtain another sample from the same
given volume using the same sampling and analysis procedures used in Step 2.
Step 4. If the concentration in the sample from the treated soil is less than or equal to
the 1/10th of the concentration in the sample of the untreated soil (or less than
10 x UTS), then you can conclude that the alternative soil treatment standard
has been attained for that volume of soil. Otherwise, you cannot conclude that
the treatment standard has been attained.
If 10 x UTS is the selected standard, then the decision rule is simplified even further: the
sample analysis result (from one or more grab samples representing the given volume of soil)
must be less than 10 x UTS.
Hypothetical Example: Using the Nonstatistical Method to Evaluate Attainment of the
90-Percent Reduction Standard
A wood preserving facility is closing a tank that contained spent formulations from a wood
preserving process (F035). Upon removal of the tank, the operator discovered a small patch of
soil contaminated with F035. The operator excavated the soil and placed it into a 55-gallon
drum. Because the excavated soil contains a listed hazardous waste, Land Disposal
Restrictions under RCRA apply. The applicable standard is for "nonwastewaters" and can be
found in the table at 40 CFR 268.40. The facility operator decides to apply the alternative
treatment standards for contaminated soil (10 x UTS or 90-percent reduction). Because the
volume of soil subject to LDRs is small, the operator decides to use the "small volume"
approach to determine attainment of the 90-percent reduction standard:
Stepl.
Step 2.
The "given volume" of soil is the volume of soil in the drum.
The operator obtains a soil core representing the full thickness of the soil in the
drum and submits this sample for laboratory analysis. The concentrations of the
hazardous constituents are as follows:
Hazardous
Constituent
Arsenic
Chromium
UTS for Non-
wastewaters
(ppm TCLP)
(from the UTS
Table at
§ 268.48)
5.0
0.6
10 x UTS
(ppm TCLP)
50
6.0
Cone. In Sample
Obtained From
Untreated Soil
(ppm TCLP)
420
120
Target
Treatment Level
For 90%
Reduction (ppm
TCLP)
42*
12
Step 3.
' Compliance also may be demonstrated by achieving 10 x UTS, or 50 ppm.
After treatment of the soil, the treatment facility obtains another sample using the
same sampling and analysis procedures used in Step 2. The concentrations of
hazardous constituents are as follows:
Arsenic (TCLP): 48 ppm
Chromium (TCLP): 10 ppm
Interim Guidance
16
September 2001
-------
Step 4. The concentration of arsenic in the treated soil is not less than the target
treatment level for 90-percent reduction; however, it is less than 10 x UTS.
Therefore, the alternative treatment standard is attained for arsenic. The
concentration of chromium in the treated soil is less than the target treatment
level for 90-percent reduction. Therefore, the alternative treatment standard also
is attained for chromium.
2.3.2 What Methods Can I Use to Determine Attainment of the UTS or 10 x UTS?
The concentration level treatment standards established for compliance with RCRA Land
Disposal Restrictions, such as the universal treatment standards (UTS), represent
concentration levels that should never be exceeded. To comply with the UTS (or to comply with
the alternative of 10 x UTS for hazardous soils), no portion of the waste may exceed the
standard. If testing results show that "hot spots" remain, this is evidence that the treatment was
not effective and there is noncompliance with the LDR treatment requirements (see 63 FR
28567, May 26, 1998). You should consider the amount of variability in the treated soil to
ensure compliance with the UTS or 10 x UTS. Statistical variability is "built in" to the LDR
treatment standards (USEPA 1991c), and it is expected that the mean will be well below the
standard for all portions of the waste to be below the standard (see Figure 3).
To determine attainment of a
concentration level LDR treatment
standard such as the UTS (or 10 x UTS),
conduct waste-testing in accordance with
your WAP and determine whether or not
any sample analysis result exceeds the
standard. If any results exceed the
standard, then you must conclude that the
standard is not met. (Note that samples
of the untreated soil are not required to
determine attainment of the UTS or 10 x
UTS). Though simple in practice, this
simple exceedance rule has a potential
limitation: a large number of samples are
required to have a high degree of
confidence that no portion of the waste
exceeds the standard.8
Sample
Mean
UCL on Upper
Percentile or
"Tolerance Limit"
Concentration
Confidence Interval on
99th Percentile
"Point estimate" of
99th percentile
Figure 3. To comply with the alternative soil treatment
standard of 10 x UTS, the mean concentration must be well
below the standard for all portions of the soil to be at or below
the treatment standard.
Though not required by regulation, some
operators may wish to evaluate their
sample analysis data statistically to quantify the level of "comfort" they can have in concluding a
standard is met. This could be done by calculating an upper percentile (such as the 99th
percentile) using actual waste sampling results and then comparing this upper percentile to the
LDR standard. An upper percentile serves as a reasonable approximation of the maximum
8 The exceedance rule has statistical properties. The statistical performance (1 OC ) can be determined
for given number of samples, n (all less than or equal to the standard), by (1 (X) = 1 p" where p equals the
proportion of the waste that must have concentrations less than or equal to the standard (e.g., 0.99).
Interim Guidance
17
September 2001
-------
concentration found in any portion of the waste. This approach is consistent with the manner in
which the LDR concentration level treatment standards are calculated each standard is
calculated as the 99th percentile of the data obtained from a properly operating waste treatment
process (USEPA 1988, 1991c).
The 99th percentile can be estimated from a set of samples drawn from the waste or soil by
using an upper confidence limit fora percentile. You can use an upper confidence limit on a
percentile to determine attainment of the standard as follows:
If the upper confidence limit on the percentile is less than or equal to the
applicable LDR standard (such as the UTS or 10 x UTS), then the waste can be
judged in compliance with the standard (see Figure 3), as long as no individual
sample values exceed the standard.
If the upper confidence limit on the percentile exceeds the standard (but all
sample values are less than or equal to the standard), then the waste still could
be judged in compliance with the standard. However, you would not have the
specified level of confidence that the specified proportion (e.g., 0.99) of the
waste complies with the standard.
Methods for calculating an upper confidence limit on a proportion (sometimes referred to as a
tolerance limit) are fairly simple and are described in several USEPA guidance documents (for
example, see Chapter 7 in USEPA 1989, and USEPA 1992) and statistical references (e.g.,
Hahn and Meeker 1991, and Guttman 1970).
2.3.3 What Statistical Methods Can I Use to Determine Attainment of the Alternative Soil
Treatment Standard of 90-Percent Reduction?
Statistical methods can be used to determine if a given volume of soil has been treated such
that there is a 90-percent reduction from the initial concentration of hazardous constituents.
This involves use of a statistical test selected from a category of tests known as "two-sample"
tests. The statistical tests are called two-sample tests because they involve two sets of
samples, one drawn independently from the untreated soil and another drawn independently
from the treated soil, so that a comparison can be made between the "before" and "after"
conditions of the soil.9 That is, the generator will test the soil before treatment and again after
treatment, then perform the statistical test to determine if 90-percent reduction has been
attained. For all of the statistical tests presented in this guidance, it is necessary that the
samples be obtained using a random or systematic sampling plan.
We present two "tiers" of statistical tests for determining attainment of the 90-percent reduction
standard. Under the first tier, we present a "quick and simple" method that does not require
statistical calculations or assumptions about the distributional form of the data (see Section
2.3.3.1). The test is known as the Nonparametric Test of Location. The test is quick and
easy to use and may be preferred by users of this guidance who have little or no training in
9 The statistical methods for determining 90-percent reduction described in this guidance involve the use of
independent samples obtained from the untreated and treated soil. These tests should not be confused with a set of
statistical tests that deal with analyzing "paired" data.
Interim Guidance 18 September2001
-------
statistics. The test does not require the assumption of normally distributed data. One limitation
of the test is that it lacks statistical "power" - that is, compared with other statistical methods
(described below) the test is less likely to show that 90-percent reduction has been attained.
The statistical tests in the second tier are more powerful but require more calculations. If both
sets of data (i.e., the data representing the untreated soil and the data representing the treated
soil) exhibit an approximately normal distribution or can be transformed to a normal distribution,
then Welch's t-Test can be used (see Section 2.3.3.2). Welch's t-Test does not require the
same number of samples in each group of data and does not require that the variances of the
two groups of data are equal. If the distributions of the two groups of data are unknown or
cannot be readily identified as normal or lognormal, a non-parametric alternative to Welch's test
should be used. The Wilcoxon Rank Sum test is recommended for use where the underlying
distribution of the data is unknown and cannot be readily identified, or when a significant
percentage (e.g., >20%) of the combined data set are reported as "nondetects" (see Section
2.3.3.3).
Checking Data for Normality:
The assumption of normality is very important, as it is the basis for many statistical tests. While the
assumption of a normal distribution (i.e., a "mound-shaped" frequency distribution) is convenient for
statistical testing purposes, it is not always appropriate. For example, sometimes data are highly
skewed (such as with a lognormal distribution in which the natural logarithms of the data exhibit a normal
distribution), orthey may have no specific shape at all. If the assumption of normality is not satisfied,
then you should consider using an alternative nonparametric test (see list of tests in Table 1).
You can check data sets for normality by using graphical methods, such as histograms, box and whisker
plots, and normal probability plots, or by using numerical tests such as Filliben's Statistic or the Shapiro-
Wilktest. We recommend the Shapiro-Wilk test as a superior method for testing normality of the data.
The specific method for implementing the Shapiro-Wilk Test is described in Gilbert (1987) and can be
performed with EPA's DataQUEST free software (USEPA 1997) or other commercially available
statistical software. EPA's Guidance for Data Quality Assessment, EPA QA/G-9 (USEPA 1998c) also
describes methods you can use to check data for normality.
2.3.3.1 A "Quick and Simple" Statistical Method for Determining 90-Percent
Reduction
To test whether the treatment process has resulted in 90-percent reduction from the initial
concentration in the untreated soil, the quick and simple statistical method described here can
be used. All that is required to perform the test is knowing the number of samples representing
the soil before treatment, the number of samples representing the soil after treatment,
identification of the smallest observation in the "before" treatment data set, and use of a lookup
table. The method described below is a modification of the nonparametric test of location
(Rosenbaum 1954). Also, note that the presence of one or more extreme values within the
data sets could further reduce the power of the test (i.e., if there is a value in the untreated soil
data set that is much /owerthan the bulk of the other values, and/or there is a value in the
treated soil data set that is much higher than the bulk of the other values in the data set, then
the test will have reduced statistical power).
Interim Guidance 19 September2001
-------
The procedure for performing the nonparametric test of location is as follows:
Step 1. Count the number of samples (nv) used to characterize the untreated soil, and
count the number of samples (nT) used to characterize the treated soil.
Step 2. Use Table B-1 (found in Appendix B - Statistical Tables) (for 90% confidence) or
Table B-2 (for 95% confidence) to obtain the critical value corresponding to nv
and nT.
Step 3. Identify the smallest value in the set of samples obtained from the untreated soil
and divide the value by 10.
Step 4. Count the number of samples (s) from the treated soil that are less than or equal
to the value obtained in Step 3. If s is greater than or equal to the critical value
from the table, then you can conclude that 90-percent reduction has been
attained. If s is less than the value in the table, then you cannot conclude that
90-percent reduction has been achieved. If the "quick and simple" test fails to
show that 90-percent reduction has been achieved, then consider evaluating the
data using a more powerful statistical method such as Welch's t-Test (Section
2.3.3.2) or the Wilcoxon Rank Sum test (Section 2.3.3.3).
Hypothetical Example: Using the "Quick and Simple" Nonparametric Statistical Test to
Evaluate Attainment of the 90-Percent Reduction Standard
Using data obtained from a site
characterization, the site operator
delineates a volume of hazardous soil
known to have contaminant concentrations
greater than 10 x UTS within the defined
volume (Figure 4). To determine
attainment of the 90-percent reduction
standard, the operator obtains eight
random samples from the volume of
untreated soil (note that the samples also
could be obtained from a pile of soil that is
the complete excavation of the block).
The volume of soil is then treated using an
ex situ soil washing technology.
After treatment, a new set of seven
samples is obtained and analyzed. The
analytical results are as follows (in ppm):
Volume of Untreated Soil
%= 8 random samples
Pile of Treated Soil
nT= 7 random samples
/f5 P P FTlK
/["I j j I j j j f 1\
U L! JJ U U u ij
Figure 4. Sample collection strategy for measuring
attainment of 90-percent reduction.
Untreated Soil (ppm): 1200, 800, 400, 540, 370, 260, 230, 200
Treated Soil (ppm): 25, 18, 15, 14, 12, 8, 6
Interim Guidance
20
September 2001
-------
Use the "quick and simple" nonparametric method to determine if the treatment process has
attained the 90-percent reduction standard:
Step 1. The number of samples (nv) used to characterize the untreated soil is 8. The
number of samples (nT) used to characterize the treated soil is 7.
Step 2. Using Table B-1 (for 90% confidence) found in Appendix B, we obtain a critical
value of 3 corresponding to nu = Q and nT = 7.
Step 3. The smallest value in the set of samples obtained from the untreated soil is 200
ppm. 200 divided by 10 equals 20.
Step 4. There are 6 samples from the treated soil that are less than or equal to 20.
Because 6 is greater than or equal to 3 (the critical value from the table), then
you can conclude with 90% confidence that 90-percent reduction has been
attained.
2.3.3.2 Welch's t-Test
If both sets of data (i.e., the data representing the untreated soil and the data representing the
treated soil) exhibit an approximately normal distribution or can be transformed to a normal
distribution, then Welch's t-Test can be used. Welch's t-Test does not require the same
number of samples in each group of data and does not require that the variances of the two
groups of data are equal. If the distributions of the two groups of data are unknown or cannot
be readily identified as normal or lognormal, or a large percentage of the data (e.g., >20%) is
reported as "nondetect", then the nonparametric Wilcoxon Rank-Sum test should be used
instead (see Section 2.3.3.3).
Procedure
Using a simple random or systematic sampling design, obtain a set of samples representing the
untreated soil known to have contamination with concentrations greater than 10 x UTS. After
treatment of the soil, obtain a new set of samples representing the same mass of soil.
Multiply each datum from the untreated soil (Ui) by 0.1 such that each is reduced by 90
percent of its original value. The 90-percent reduced data will serve as the reference data set
(ref). If 90-percent reduction has been attained, then the mean concentration in the treated soil
should be the same as the mean concentration in the reference data set or shifted to the left of
the mean of the reference data set.
Step 1: Calculate the sample mean XT and the sample variance s^ for the "Treated"
soil. Calculate the sample mean xref and the sample variance s^ for the
reference data set. The number of samples representing the untreated and
treated soil do not need to be the same.
Interim Guidance 21 September 2001
-------
Step 2:
Calculate Welch's t-Statistic as follows:
= (xT-xnf)
n
ref
Equation 1
Step 3: Calculate the approximate degrees of freedom as follows:
df= ^ + ^- / ^ " '[ +^'*J< "7 Equation 2
~4
, Sref
i
Yt Yt
'if r*ref
7
(s2T/nT)
I
nT-\
(Sref/nref)2
Hre ~1
Round df to the nearest integer.
Step 4: Use Table B-3 in Appendix B to find the critical value tl_a such that
100( 1 - a )% of the t-distribution for the nearest degrees of freedom (df).
Step 5: If t < -tl_a , then conclude that 90 percent reduction has been attained. If,
however, t > tl_a , then you cannot conclude that 90 percent reduction has
been attained.
Hypothetical Example: Using Welch's t-Test to Evaluate Attainment of the 90-Percent
Reduction Standard
In Situ Untreated Soil
Using data obtained from a site
characterization, the site operator
delineates a unit of hazardous soil known
to have contaminant concentrations
greater than 10 x UTS within the defined
volume (Figure 5). To determine the
mean and the variance of the
concentration of the constituent of
concern, the operator obtains six random
samples from the unit of untreated soil
(note that the samples also could be
obtained from a pile of soil that is the
complete excavation of the unit). The unit
of soil is then treated using an ex situ soil
washing technology.
After treatment, a new set of eight random
samples is Obtained and analyzed. The Figure 5. Sample collection strategy for measuring
sample analysis results are as follows: attainment of 90-percent reduction using Welch's t-Test.
Rle of Treated Soil
Interim Guidance
22
September 2001
-------
Untreated Soil (ppm) (Ut): 400, 540, 260, 160, 370, 80
Reference (ppm), 0.1 (Ut): 40, 54, 26, 16, 37, 8
Treated Soil (ppm) (Tt): 25, 12, 18,8, 14,6, 15,21
Calculate Welch's t statistic to determine if the treatment process has attained the 90 percent
reduction standard:
Step 1: Calculate the sample mean and the variance for the treated soil and the
reference data set.
Number of Samples
Sample Mean
Sample Variance
Treated Soil
nT = 8
XT = 14.9
4 = 40.7
Reference Data
nref=Q
Xref=30.2
-------
Step 5: Welch's t-Statistic (-2.1 1 ) is less than the critical value of -1 .440 therefore we
can conclude, with 90-percent confidence, that the 90 percent reduction soil
treatment standard has been attained for the given volume of soil.
2.3.3.3 Wilcoxon Rank-Sum Test
The Wilcoxon Rank Sum test is recommended for use where the underlying distribution of the
data is unknown and cannot be readily identified or when a significant percentage (e.g., >20%)
of the combined data sets are reported as "nondetects."
Procedure
Let nT represent the number of samples obtained from the "Treated" soil. Let nv represent
the number of samples obtained from the "Untreated" soil. Multiply each datum from the
untreated soil by 0.1 such that each is reduced by 90 percent of its original value. The 90-
percent reduced data, n, , will serve as the reference data set. If 90-percent reduction has
been attained, then the concentrations in the treated soil should tend to be the same as or less
than the concentrations in the reference data set.
Step 1 : Combine all of the reference data (i.e., the untreated data reduced by 90-
percent) and the treated soil data into a single data set. Sort and rank the
combined values from smallest to largest, assigning the rank of 1 to the smallest
result, the rank of 2 to the next smallest result, and so on. Keep track of which
samples belong to the reference population and the treated population. If two or
more measurements are the same, assign all of them a rank equal to the
average of the ranks they occupy.
Step 2: Calculate R as the sum of the ranks of the data from the treated soil, then
calculate
) n3
2
Step 3: Use Table B-4 in Appendix B to find the critical value wa for the appropriate
values of nT , nref , and a . If W < wa , reject the null hypothesis and
conclude that 90-percent reduction is attained (i.e., conclude that the
concentrations in the treated soil tend to be the same as or less than the
concentration found in the reference soil data set). Otherwise, you cannot
conclude that 90-percent reduction was attained.
Interim Guidance 24 September 2001
-------
Hypothetical Example: Using the Wilcoxon Rank Sum Test to Evaluate Attainment of the
90-Percent Reduction Standard
Using data obtained from a site
characterization, the site operator
delineates a unit of soil known to have
contaminant concentrations no less that
10 x UTS within the defined volume
(Figure 6). The operator obtains
= nrer
= 8 random samples from the
unit of untreated soil (note that the
samples also could be obtained from a pile
of soil that is the complete excavation of
the unit of soil). The unit of soil is then
treated using an ex situ soil washing
technology.
After treatment, a new set of nT = 7
samples is obtained from the treated soil
and analyzed. A table of the data is
created denoting data representing the
untreated soil, the reference data, and the
treated soil.
In Situ Untreated Soil
%= V= 8
Figure 6. Sample collection strategy for measuring
attainment of 90-percent reduction using the Wilcoxon Rank
Sum test.
Calculate the Wilcoxon Rank-Sum Test to determine if the treatment process has attained the
90 percent reduction standard:
Treated Soil (ppm) (Tt): 17, 23, 26, 5, 13, 13, 12
Untreated Soil (ppm) (Ut): 160, 200, 50, 40, 80, 100, 70, 30
Reference (ppm), 0.1 (Ut): 16, 20, 5, 4, 8, 10, 7, 3
Step 1: Combine the data for the treated soil and the data from the reference data set
and sort and rank the values (the treated soil data are denoted by *):
Data: 3 4 5 5* 7 8 10 12* 13* 13* 16 17* 20 23* 26*
Rank: 1 2 3.5 3.5* 5678* 9.5* 9.5* 11 12* 13 14* 15*
Note that the data occupying ranks 3 and 4 are "ties" (both value are 5).
Therefore, we assign both values a rank equal to the average of the ranks they
occupy (i.e., (3+4)72=3.5). The same situation occurs at ranks 9 and 10 and
both values are assigned a rank equal to the average of 9 + 10 (i.e.,
(9+10)72=9.5).
Interim Guidance
25
September 2001
-------
Step 2: Calculate R as the sum of the ranks of the data from the treated soil:
R = 3.5 + 8 + 9.5 + 9.5+ 12+14+ 15 = 71.5
Then calculate W :
W = R- '' = 71.5 -= 43.5
2 2
Step 3: Using Table 4 in Appendix B, the critical value ( w0 10 ) is found to be 17.
Because 43.5 > 17, do not reject the null hypothesis. In other words, we cannot
conclude with 90-percent confidence that 90-percent reduction has been
attained.
Interim Guidance 26 September 2001
-------
3. WHAT ARE THE NOTIFICATION, CERTIFICATION, AND RECORDKEEPING
REQUIREMENTS FOR CONTAMINATED SOILS?
Contaminated soil subject to the land disposal restrictions must comply with the same
recordkeeping requirements as other wastes subject to LDR. The generator of a hazardous
soil must comply with the applicable provisions of 40 CFR 268.7(a). This would include a
certification statement sent with the initial waste shipment and retained in the generator's files.
The statement should certify that the soil [does/does not] contain a listed hazardous waste and
[does/does not] exhibit a hazardous characteristic. Note that certifications accompanying waste
shipments need only be provided for hazardous soils shipped off site. For hazardous soils
remaining on site, this certification is not required.
Once a characteristic soil is treated to remove its hazardous characteristic, it is no longer
subject to Subtitle C regulation. However, it could require further treatment if the soils were
prohibited from land disposal at the point of generation and the underlying hazardous
constituents remain present at concentrations greater than 10 x UTS after treatment to remove
the characteristic. Special notification requirements for treated characteristic wastes (found at
40 CFR 268.9(d)) allow generators to send a one-time notice to the EPA region or their state
agency instead of the Subtitle D disposal facility. This notification must be placed in the
generator's files and include the following information:
the name and address of the receiving facility; and
a description of the waste including hazardous waste codes, treatability groups
and subcategories, and any underlying hazardous constituents
The generator also must prepare a certification statement in accordance with § 268.7(b)(5) to
accompany the notification. Both the certification and notification statements must be updated
if there are any changes to the waste or receiving facility. Such changes must be submitted to
the appropriate EPA region or state agency on an annual basis.
Facilities should also be able to demonstrate how the alternative soil treatment standards have
been met. As a result, you should keep records documenting the following:
The rationale for arriving at a manageable list of monitoring constituents for the
hazardous soil to be treated,
The rationale for sampling protocols or methodology for collecting representative
samples of hazardous constituents of concern in the contaminated soil (e.g.,
QAPP, sampling plan, and spatial analyses to delineate volumes of soil with
constituent concentrations greater than 10 x UTS soils),
The methodology for determining 90-percent reduction, and
Treatment data used to verify 90-percent reduction.
Interim Guidance 27 September 2001
-------
References
Note: Due to the dynamic nature of the Internet, the location and content of web sites given in this document may
change over time. If you find a broken link to an EPA document, use the search engine at http://www.epa.gov/ to
find the document. Links to web sites outside the U.S. EPA web site are for the convenience of the user, and the
U.S. EPA does not exercise any editorial control over the information you may find at these external web sites.
ASTM D 4220-95. 1995. Standard Practices for Preserving and Transporting Soil Samples.
West Conshohocken, PA. http://www.astm.org
ASTM D 6311-98. 1998a. Standard Guide for Generation of Environmental Data Related to
Waste Management Activities: Selection and Optimization of Sampling Design. West
Conshohocken, PA.
ASTM D 4547-98. 1998b. Standard Guide for Sampling Waste and Soils for Volatile Organics.
West Conshohocken, PA.
ASTM D 6169-98. 1998c. Standard Guide for Selection of Soil and Rock Sampling Devices
Used With Drill Rigs for Environmental Investigations. West Conshohocken, PA.
ASTM D 6418-99. 1999. Standard Practice for Using the Disposable EnCore Sampler for
Sampling and Storing Soil for Volatile Organic Analysis. West Conshohocken, PA.
Davidson, J.R., Jr. 1995. ELIPGRID-PC: Hot Spot Probability Calculations. Battelle/Pacific
Northwest National Laboratory, Richland, WA. Software and documentation available at
http://terrassa.pnl.gov:2080/DQO/software/elipgrid.html
Gilbert, R.O. 1987. Statistical Methods for Environmental Pollution Monitoring. New York: Van
Nostrand Reinhold.
Guttman, I. 1970. Statistical Tolerance Regions: Classical and Bayesian. London: Charles
Griffin & Co.
Hahn, G.J. and W.Q. Meeker. 1991. Statistical Intervals: A Guide for Practitioners. New York:
John Wiley & Sons, Inc.
Isaaks, E.H. and R.M. Srivastava. 1989. An Introduction to Applied Geostatistics. New York:
Oxford University Press.
Journel, A.G. 1988. "Non-parametric Geostatistics for Risk and Additional Sampling
Assessment." Principles of Environmental Sampling. L.H. Keith, ed. Washington, DC:
American Chemical Society.
Mason, B.J. 1992. Preparation of Soil Sampling Protocols: Sampling Techniques and
Strategies. EPA/600/R-92/128. NTIS PB 92-220532. U.S. Environmental Protection
Agency, Office of Research and Development. Las Vegas, NV.
http://www.epa. gov:80/swerust1/cat/mason, pdf
Interim Guidance 28 September 2001
-------
Myers, J.C. 1997. Geostatistical Error Management: Quantifying Uncertainty for Environmental
Sampling and Mapping. New York: Van Nostrand Reinhold.
Rosenbaum, S. 1954. Tables for a nonparametric test of location. Annals of Mathematical
Statistics. 25:146-150.
US Army Corp of Engineers (USAGE). 1997. Engineering and Design - Practical Aspects of
Applying Geostatistics at Hazardous, Toxic, and Radioactive Waste Sites. Publication
Number ETL 1110-1-175.
http://www.usace.armv.mil/usace-docs/eng-tech-ltrs/etl1110-1-175/toc.html
USEPA. 1988. Methodology for Developing Best Demonstrated Available (BDAT) Treatment
Standards. EPA/530-SW-89-017L. Treatment Technology Section, Office of Solid
Waste. Washington, DC.
USEPA. 1989. Methods for Evaluating the Attainment of Cleanup Standards, Volume 1: Soils
and Solid Media. EPA 230/02-89-042. NTIS PB89-234959. Statistical Policy Branch,
Office of Policy, Planning, and Evaluation. Washington, DC.
http://www.epa.gov/swertio1/download/stats/vol1soils.pdf
USEPA. 1991a. GEO-EAS 1.2.1 User's Guide. EPA/600/8-91/008. Environmental Monitoring
Systems Laboratory, Las Vegas, NV.
USEPA. 1991b. Description and Sampling of Contaminated Soils-A Field Pocket Guide.
EPA/625/12-91/002. Center for Environmental Research Information. Cincinnati, OH.
USEPA. 1991c. Final Best Demonstrated Available Technology (BDAT) Background Document
for Quality Assurance/Quality Control Procedures and Methodology. NTIS PB95-
230926. Office of Solid Waste. Washington, DC.
USEPA. 1992. Methods for Evaluating the Attainment of Cleanup Standards. Volume 2: Ground
Water. EPA 230-R-92-14. Office of Policy, Planning, and Evaluation. Washington, DC.
http://www.epa.gov/swertio1/download/stats/vol2gw.pdf
USEPA. 1994a. Guidance for the Data Quality Objectives Process, EPA QA/G-4 (Revised,
August 2000). http://www.epa.gov/gualitv1/gs-docs/g4-final.pdf EPA/600/R-96/055.
Office of Environmental Information. Quality Staff. Washington, DC.
USEPA. 1994b. Waste Analysis at Facilities That Generate, Treat, Store, and Dispose of
Hazardous Wastes, a Guidance Manual. OSWER 9938.4-03.
http://www.epa.gov/epaoswer/hazwaste/ldr/guidance.htm Office of Solid Waste and
Emergency Response. Washington, DC.
USEPA. 1997. Data Quality Assessment Statistical Toolbox (DataQUEST), EPA QA/G-9D.
User's Guide and Software, http://www.epa.gov/gualitv1/dga.html. EPA/600/R-96/085.
Office of Research and Development. Las Vegas.
Interim Guidance 29 September 2001
-------
USEPA. 1998a. Management of Remediation Waste Under RCRA. EPA/530-F-98-026. Office
of Solid Waste and Emergency Response (5305W). Washington, DC.
http://www.epa.gov/epaoswer/hazwaste/ca/resource/guidance.htmtfRemediation Waste
USEPA. 1998b. EPA Guidance For Quality Assurance Project Plans, EPA QA/G-5.
EPA/600/R-98/018. Office of Research and Development, Washington, DC.
http://www.epa.gov/quality1/
USEPA. 1998c. Guidance for Data Quality Assessment, EPA QA/G-9 (QAOO Update, revised
July 2000). EPA/600/R-96/084. Final, http://www.epa.gov/qualitv1/. Office of
Environmental Information, Quality Staff. Washington, DC.
USEPA. 1998d. "Phase IV Land Disposal Restrictions Rule - Clarification of Effective Dates."
Memorandum from Elizabeth A. Cotsworth, Acting Director Office of Solid Waste, to
RCRA Senior Policy Advisors, Regions I - X. October 19, 1998.
http://www.epa.gov/epaoswer/hazwaste/ldr/ldrmetal/memos/effectiv.pdf
USEPA. 2000a. Data Quality Objectives Process for Hazardous Waste Site Investigations EPA
QA/G-4HWFinal. EPA/600/R-00/007. Office of Environmental Information. January
2000. http://www.epa.gov/guality1/ga docs.html
USEPA. 2000b. Guidance for Choosing a Sampling Design for Environmental Data Collection,
Use in the Development of a Quality Assurance Project Plan. EPA QA/G-5S. Quality
Staff, Office of Environmental Information. Washington, D.C. Peer Review Draft. August
2000. http://www.epa.gov/guality1/ga docs.html
Interim Guidance 30 September 2001
-------
APPENDIX A:
"MANAGEMENT OF REMEDIATION WASTE UNDER RCRA"
-------
October 14, 1998
MEMORANDUM
SUBJECT: Management of Remediation Waste Under RCRA
TO: RCRA/CERCLA Senior Policy Managers
Regional Counsels
FROM: Timothy Fields, Jr., Acting Assistant Administrator for
Solid Waste and Emergency Response /signed/
Steven A. Herman, Assistant Administrator for
Enforcement and Compliance Assurance /signed/
Rapid clean up of RCRA corrective action facilities and Superfund sites is one of the
Agency's highest priorities. In this context, we often receive questions about management of
remediation waste under the Resource Conservation and Recovery Act (RCRA). To assist you in
successfully implementing RCRA requirements for remediation waste, this memorandum
consolidates existing guidance on the RCRA regulations and policies that most often affect
remediation waste management. We encourage you to work with the regulations, policies and
approaches outlined in this memorandum to achieve our cleanup goals as quickly and efficiently as
possible.
Note that not all remediation wastes are subject to RCRA Subtitle C hazardous waste
requirements. As with any other solid waste, remediation wastes are subject to RCRA Subtitle C
only if they are listed or identified hazardous waste. Environmental media are subject to RCRA
Subtitle C only if they contain listed hazardous waste, or exhibit a characteristic of hazardous
waste. These distinctions are discussed more completely below.
The information in this memo is divided into three categories: information on regulations
and policies that apply to all remediation waste; information on regulations and policies that apply
only to contaminated media; and, information on regulations and policies that apply only to
contaminated debris. Most of the references cited in this memo are available over the Internet.
The Federal Register notices published after 1994 are available at www.access.gpo.gov/nara; the
guidance memos and other EPA documents are available at www.epa.gov/correctiveaction.
Federal Register notices and other documents are also available through the RCRA/CERCLA
hotline: in Washington D.C., call (703) 412-9810; outside Washington D.C., call (800) 424-9346;
and hearing impaired call (800) 553-7672. The hotline's hours are Monday - Friday, excluding
-------
Federal holidays, 8:00 - 5:00, eastern standard time. Many EPA guidance memos and other
documents may also be obtained through the RCRA/CERCLA hotline fax-back system. To
obtain a list of documents available over the fax-back system, and fax-back system code numbers,
call the RCRA/CERCLA hotline at the numbers listed above.
I hope this information will assist you as you continue to make protective, inclusive, and
efficient cleanup decisions. If you have additional questions or require more information, please
contact Robert Hall or Greg Madden, of our staffs, on (703) 308-8484 or (202) 564-4229
respectively.
Regulations and Policies that Apply to All Remediation Wastes
Area of Contamination Policy. In what is typically referred to as the area of
contamination (AOC) policy, EPA interprets RCRA to allow certain discrete areas of generally
dispersed contamination to be considered RCRA units (usually landfills). Because an AOC is
equated to a RCRA land-based unit, consolidation and in situ treatment of hazardous waste
within the AOC do not create a new point of hazardous waste generation for purposes of RCRA.
This interpretation allows wastes to be consolidated or treated in situ within an AOC without
triggering land disposal restrictions or minimum technology requirements. The AOC
interpretation may be applied to any hazardous remediation waste (including non-media wastes)
that is in or on the land. Note that the AOC policy only covers consolidation and other in situ
waste management techniques carried out within an AOC. For ex situ waste management or
transfer of wastes from one area of contamination to another, see discussion of corrective action
management units, below.
The AOC policy was first articulated in the National Oil and Hazardous Substances
Pollution Contingency Plan (NCP). See 53 FR 51444 for detailed discussion in proposed NCP
preamble; 55 FR 8758-8760, March 8, 1990 for final NCP preamble discussion. See also, most
recent EPA guidance, March 13, 1996 EPA memo, "Use of the Area of Contamination Concept
During RCRA Cleanups."
Corrective Action Management Units (CAMUs). The corrective action management
unit rule created a new type of RCRA unit - a Corrective Action Management Unit or CAMU
specifically intended for treatment, storage and disposal of hazardous remediation waste. Under
the CAMU rule, EPA and authorized states may develop and impose site-specific design,
operating, closure and post-closure requirements for CAMUs in lieu of MTRs for land-based
units. Although there is a strong preference for use of CAMUs to facilitate treatment,
remediation waste placed in approved CAMUs does not have to meet LDR treatment standards.
The main differences between CAMUs and the AOC policy (discussed above) are that,
when a CAMU is used, waste may be treated ex situ and then placed in a CAMU, CAMUs may
be located in uncontaminated areas at a facility, and wastes may be consolidated into CAMUs
from areas that are not contiguously contaminated. None of these activities are allowed under the
AOC policy, which, as discussed above, covers only consolidation and in situ management
techniques carried out within an AOC.
-------
CAMUs must be approved by EPA or an authorized state and designated in a permit or
corrective action order. In certain circumstances, EPA and states (including states that are not
authorized for the CAMU regulations) may use other mechanisms to approve CAMUs. See, 58
FR 8677, February 16, 1993; appropriate use of RCRA Section 7003 orders and comparable state
orders is discussed below and in an EPA guidance memo from J. Winston Porter to EPA Regional
Administrators, "RCRA Permit Requirements for State Superfund Actions," November 16, 1987,
OSWER Directive 9522.00-2. In addition, as appropriate, CAMUs may be approved by EPA as
an applicable or relevant and appropriate requirement during a CERCLA cleanup using a record
of decision or by an authorized state during a state cleanup using a CERCLA-like authority and a
similar state document. See, e.g., 58 FR 8679, February 16, 1993. An opportunity for the public
to review and comment on tentative CAMU approvals is required by the regulations when
CAMUs are approved using permitting procedures and as a matter of EPA policy when CAMUs
are approved using orders. EPA recommends that, whenever possible, remediation project
managers combine this public participation with other public involvement activities that are
typically part of remediation. For example, public notice of tentative approval of a CAMU could
be combined with public notice of a proposed plan under CERCLA.
The CAMU rule is currently subject to litigation; however, the suit has been stayed
pending promulgation of the final HWIR-Media regulations. Although EPA proposed to
withdraw CAMUs as part of the HWIR-Media proposal, the Agency now intends to retain the
CAMU rule. The Agency encourages approval of CAMUs when they are appropriate given the
site-specific conditions.
The CAMU regulations are at 40 CFR 264.552, promulgated February 16, 1993 (58 FR
8658). The differences between CAMUs and AOCs are discussed in more detail in the March 13,
1996 EPA guidance memo, "Use of the Area of Contamination Concept During RCRA
Cleanups."
Corrective Action Temporary Units (TUs). Temporary units, like corrective action
management units, are RCRA units established specifically for management of hazardous
remediation waste. The regulations for temporary units (TUs) were promulgated at the same time
as the regulations for corrective action management units. The CAMU regulations established
land-based units for treatment, storage and disposal of remediation waste; the TU regulations
established non-land based units for treatment and storage of hazardous remediation waste. Under
the TU regulations, EPA and authorized states may modify existing MTR design, operating and
closure standards for temporary tank and container units used to treat and store hazardous
remediation waste. Temporary units may operate for one year, with an opportunity for a one year
extension.
Like CAMUs, temporary units must be approved by EPA or an authorized state and
designated in a permit or corrective action order. In certain circumstances, EPA and states
(including states that are not authorized for the TU regulations) may use other mechanisms to
approve TUs. See, 58 FR 8677, February 16, 1993; appropriate use of RCRA Section 7003
orders and comparable state orders is discussed below and in an EPA guidance memo from J.
Winston Porter to EPA Regional Administrators, "RCRA Permit Requirements for State
Superfund Actions," November 16, 1987, OSWER Directive 9522.00-2. In addition, as
appropriate, TUs may be approved by EPA as an applicable or relevant and appropriate
-------
requirement during a CERCLA cleanup using a record of decision or by an authorized state
during a state cleanup using a CERCLA-like authority and a similar state document. Placement of
waste in tanks or containers, including temporary units, is not considered land disposal.
Therefore, waste does not have to be treated to meet LDR treatment standards prior to being
placed in a TU. Of course, LDRs must be met if hazardous remediation wastes are eventually
land disposed, for example, after they are removed from the TU; however, if treatment in a TU
results in constituent concentrations that comply with applicable land disposal restriction
treatment standards, no further treatment prior to land disposal is required as a condition of the
LDRs.
An opportunity for the public to review and comment on tentative TU approvals is
required by the regulations when TUs are approved using permitting procedures and as a matter
of EPA policy when TUs are approved using orders. As with CAMUs, EPA recommends that
whenever possible, remediation project managers combine this public participation with other
public involvement activities that are typically part of remediation. For example, public notice of
tentative approval of a temporary unit could be combined with public notice of a proposed plan
under CERCLA.
The TU regulations are at 40 CFR 264.553, promulgated February 16, 1993 (58 FR
8658).
Determination Of When Contamination is Caused by Listed Hazardous Waste.
Where a facility owner/operator makes a good faith effort to determine if a material is a listed
hazardous waste but cannot make such a determination because documentation regarding a
source of contamination, contaminant, or waste is unavailable or inconclusive, EPA has stated
that one may assume the source, contaminant or waste is not listed hazardous waste and,
therefore, provided the material in question does not exhibit a characteristic of hazardous waste,
RCRA requirements do not apply. This approach was first articulated in the Proposed NCP
preamble which notes that it is often necessary to know the source of a waste (or contaminant) to
determine whether a waste is a listed hazardous waste under RCRA1 and also notes that, "at many
CERCLA sites no information exists on the source of the wastes." The proposed NCP preamble
goes on to recommend that the lead agency use available site information such as manifests,
storage records and vouchers in an effort to ascertain the sources of wastes or contaminants, but
that when this documentation is not available or inconclusive the lead agency may assume that the
wastes (or contaminants) are not listed RCRA hazardous wastes. This approach was confirmed in
the final NCP preamble. See, 53 FR 51444, December 21, 1988 for proposed NCP preamble
discussion; 55 FR 8758, March 13, 1990 for final NCP preamble discussion.
This approach was also discussed in the FEWIR-Media proposal preamble, 61 FR 18805,
April 29, 1996, where it was expanded to also cover dates of waste disposal - i.e., if, after a good
faith effort to determine dates of disposal a facility owner/operator is unable to make such a
determination because documentation of dates of disposal is unavailable or inconclusive, one may
Listing determinations are often particularly difficult in the remedial context because the listings are generally
identified by the sources of the hazardous wastes rather than the concentrations of various hazardous constituents;
therefore, analytical testing alone, without information on a waste's source, will not generally produce information that will
conclusively indicate whether a given waste is a listed hazardous waste.
-------
assume disposal occurred prior to the effective date of applicable land disposal restrictions. This
is important because, if hazardous waste was originally disposed of before the effective dates of
applicable land disposal restrictions and media contaminated by the waste are determined not to
contain hazardous waste when first generated (i.e., removed from the land, or area of
contamination), the media are not subject to RCRA requirements, including LDRs. See the
discussion of the contained-in policy, below.
Site Specific LDR Treatment Variances. The regulations for site-specific LDR
treatment variances allow EPA and authorized states to establish a site-specific LDR treatment
standard on a case-by-case basis when a nationally applicable treatment standard is unachieveable
or inappropriate. Public notice and a reasonable opportunity for public comment must be
provided before granting or denying a site-specific LDR treatment variance. EPA recommends
that remediation project managers combine this public involvement with other public involvement
activities that are typically part of remediation. Regulations governing site-specific LDR
treatment variances are at 40 CFR 268.44(h), promulgated August 17, 1988 (53 FR 31199) and
clarified December 5, 1997 (62 FR 64504). The most recent EPA guidance on site-specific LDR
treatment variances, which includes information on establishing alternative LDR treatment
standards, is in the January 8, 1997 guidance memo, "Use of Site-Specific Land Disposal
Restriction Treatability Variances Under 40 CFR 268.44(h) During Cleanups."
In 1996, EPA revised its policy on state authorization for site-specific LDR treatment
variances and began encouraging states to become authorized to approve variances. See, HWIR-
Media proposal, 61 FR 18828 (April 29, 1996).
On May 26, 1998, EPA promulgated additional site-specific land disposal restriction
treatment variance opportunities specific to hazardous contaminated soil. These opportunities are
discussed below.
Treatability Studies Exemption. The term "treatability study"as defined at 40 CFR
260.10 refers to a study in which a hazardous waste is subjected to a treatment process to
determine: (1) whether the waste is amenable to the treatment process; (2) what pretreatment (if
any) is required; (3) the optimal process conditions needed to achieve the desired treatment; (4)
the efficiency of a treatment process for a specific waste or wastes; or, (5) the characteristics and
volumes of residuals from a particular treatment process. Under regulations at 40 CFR 261.4(e)
and (f), hazardous wastes managed during a treatability study are exempt from many RCRA
Subtitle C requirements. The regulations limit the amount of waste that may be managed under
an exempt treatability study to, generally, 1000 kg of hazardous waste or 1 kg of acutely
hazardous waste per study. For contaminated environmental media, the volume limit is, generally,
10,000 kilograms of media that contain non-acutely hazardous waste and 2,500 kilograms of
media that contain acutely hazardous waste per study. There are also limits on the types and
lengths of studies that may be conducted under the exemption and record keeping and reporting
requirements. Regulations governing treatability studies are at 40 CFR 261.4(e) and (f),
associated preamble discussions at 52 FR 27290 (July 19, 1988) and 59 FR 8362 (February 18,
1994).
Exemption for Ninety Day Accumulation. Management of hazardous waste in tanks,
containers, drip pads and containment buildings does not constitute land disposal. In addition,
-------
EPA has provided an exemption for generators of hazardous waste which allows them to
accumulate (i.e., treat or store) hazardous waste at the site of generation in tanks, containers, drip
pads or containment buildings for up to ninety days without RCRA interim status or a RCRA
permit. Accumulation units must meet applicable design, operating, closure and post-closure
standards. Because putting hazardous waste in a tank, container, drip pad or containment
building is not considered land disposal, LDR treatment standards do not have to be met before
putting waste in such units. LDRs must be met if hazardous wastes are eventually land disposed,
for example, after they are removed from the accumulation unit; however, if treatment in an
accumulation unit results in constituent concentrations that comply with applicable land disposal
restriction treatment standards, no further treatment prior to land disposal is required as a
condition of the LDRs. The exemption for ninety-day accumulation is found in regulations at 40
CFR 262.34; associated preamble discussion is at 51 FR at 10168 (March 24, 1986).
Permit Waivers. Under CERCLA Section 121(e), no Federal, state or local permit is
required for on-site CERCLA response actions. EPA has interpreted CERCLA Section 121 (e) to
waive the requirement to obtain a permit and associated administrative and procedural
requirements of permits, but not the substantive requirements that would be applied through
permits.2
In addition, on a case-by-case basis, where there may be an imminent and substantial
endangerment to human health or the environment, EPA has broad authority to require corrective
action and other appropriate activities under RCRA Section 7003. Under RCRA Section 7003,
EPA has the ability to waive both the requirement to obtain a permit and the substantive
requirements that would be imposed through permits. When EPA uses RCRA Section 7003,
however, the Agency seldom uses RCRA Section 7003 to waive substantive requirements. In
rare situations where substantive requirements are waived, the Agency would impose alternative
requirements (e.g, waste treatment or storage requirements) as necessary to ensure protection of
human health and the environment. EPA may issue RCRA Section 7003 orders at, among other
sites, facilities that have been issued RCRA permits and facilities that are authorized to operate
under RCRA interim status. In discussing the use of 7003 orders, where other permit authorities
are available to abate potential endangerments, EPA generally encourages use of those other
permit authorities (e.g., 3005(c)(3) omnibus permitting authority) rather than RCRA Section
7003. Similarly, if RCRA Section 3008(h) or RCRA Section 3013 authority is available, EPA
generally encourages use of these authorities rather than RCRA Section 7003. If permit
authorities or non-RCRA Section 7003 enforcement authorities are inadequate, cannot be used to
address the potential endangerment in a timely manner, or are otherwise inappropriate for the
potential endangerment at issue, use of RCRA Section 7003 should be considered. See,
"Guidance on the Use of Section 7003 of RCRA," U.S. EPA, Office of Enforcement and
Compliance Assurance, October 1997.
In 1987, EPA issued guidance indicating that RCRA-authorized states with state waiver
authorities comparable to CERCLA 121(e) or RCRA Section 7003 could use those state waiver
authorities to waive RCRA requirements as long as the state did so in a manner no less stringent
than that allowed under the corresponding Federal authorities. These waivers are most often
Note that, under certain circumstances, substantive requirements may be waived using CERCLA. See the
ARAR waiver provisions at 40 CFR 300.430(f)(l)(ii)(C).
-------
used, as are the Federal waivers, to obviate the need to obtain a RCRA permit, rather than to
eliminate substantive requirements. See, EPA guidance memo from J. Winston Porter to EPA
Regional Administrators, "RCRA Permit Requirements for State Superfund Actions," November
16, 1987, OSWER Directive 9522.00-2.
Exemption from 40 CFR Part 264 Requirements for People Engaged in the
Immediate Phase of a Spill Response. Regulations at 40 CFR 264. l(g)(8) provide that people
engaged in treatment or containment activities are not subject to the requirements of 40 CFR part
264 if the activities are carried out during immediate response to: (1) a discharge of hazardous
waste; (2) an imminent and substantial threat of a discharge of hazardous waste; (3) a discharge of
a materials which, when discharged, becomes a hazardous waste; or, (4) an immediate threat to
human health, public safety, property or the environment from the known or suspected presence
of military munitions, other explosive material, or an explosive device. This means that, during
the immediate phase of a spill response, hazardous waste management activities do not require
hazardous waste permits (or interim status) and hazardous waste management units used during
immediate response actions are not subject to RCRA design, operating, closure or post-closure
requirements.
Of course, if hazardous waste treatment activities or other hazardous waste management
activities continue after the immediate phase of a spill response is over, all applicable hazardous
waste management and permitting requirements would apply. In addition, if spills occur at a
facility that is already regulated under 40 CFR part 264, the facility owner/operator must continue
to comply with all applicable requirements of 40 CFR Part 264 Subparts C (preparedness and
prevention) and D (contingency plan and emergency procedures). See regulations at 40 CFR
260. l(g) and associated preamble discussion at 45 FR 76626 (November 19, 1980). See also,
Sept. 29, 1986 memo from J. Winston Porter (EPA Assistant Administrator) to Fred Hansen
interpreting the 40 CFR 264. l(g) regulations.
Changes During Interim Status to Comply with Corrective Action Requirements.
Under regulations at 40 CFR 270.72(a)(5), an owner or operator of an interim status facility may
make changes to provide for treatment, storage and disposal of remediation wastes in accordance
with an interim status corrective action order issued by EPA under RCRA Section 3008(h) or
other Federal authority, by an authorized state under comparable state authority, or by a court in a
judicial action brought by EPA or an authorized state. These changes are limited to treatment,
storage and disposal of remediation waste managed as a result of corrective action for releases at
the facility in question; however, they are exempt from the reconstruction ban under 40 CFR
270.72(b). Under this provision, for example, EPA could approve a corrective action
management unit for treatment of remediation waste using a 3008(h) order (or an authorized state
could approve a CAMU using a similar state authority), even if that unit would otherwise amount
to "reconstruction." Of course, units added at interim status facilities in accordance with this
provision must meet all applicable unit requirements; for example, in the case of a CAMU, the
CAMU requirements apply. See, regulations at 40 CFR 270.72(a)(5) promulgated March 7, 1989
and associated preamble discussion at 54 FR 9599.
Emergency Permits. In the event of an imminent and substantial endangerment to human
health or the environment, EPA, or an authorized state, may issue a temporary emergency permit
for treatment, storage or disposal of hazardous waste. Emergency permits may allow treatment,
-------
storage or disposal of hazardous waste at a non-permitted facility or at a permitted facility for
waste not covered by the permit. Emergency permits may be oral or written. (If oral, they must
be followed within five days by a written emergency permit.) Emergency permits must specify the
hazardous wastes to be received and managed and the manner and location of their treatment,
storage and disposal. Emergency permits may apply for up to ninety days, but may be terminated
at any point if EPA, or an authorized state, determines that termination is appropriate to protect
human health or the environment. Emergency permits must be accompanied by a public notice
that meets the requirements of 40 CFR 124.10(b), including the name and address of the office
approving the emergency permit, the name and location of the hazardous waste treatment, storage
or disposal facility, a brief description of the wastes involved, the actions authorized and the
reason for the authorization, and the duration of the emergency permit.
Emergency permits are exempt from all other requirements of 40 CFR part 270 and part
124; however, to the extent possible and not inconsistent with the emergency situation, they must
incorporate all otherwise applicable requirements of 40 CFR part 270 and parts 264 and 266.
See, regulations at 40 CFR 270.61, originally promulgated as 40 CFR 122.27 on May 19,
1987 (45 FR 33326). EPA has also written a number of letters interpreting the emergency permit
regulations, see, for example, November 3, 1992 letter to Mark Hansen, Environmental Products
and Services Inc., from Sylvia Lowrance, Director Office of Solid Waste (available in the RCRA
Permit Policy Compendium).
Temporary Authorizations at Permitted Facilities. Under regulations at 40 CFR
270.42(e), EPA, or an authorized state, may temporarily authorize a permittee for an activity that
would be the subject of a class two or three permit modification in order to, among other things,
facilitate timely implementation of closure or corrective action activities. Activities approved
using a temporary authorization must comply with applicable requirements of 40 CFR part 264.
Temporary authorizations are limited to 180 days, with an opportunity for an extension of 180
additional days. To obtain an extension of a temporary authorization, a permittee must have
requested a class two or three permit modification for the activity covered in the temporary
authorization. Public notification of temporary authorizations is accomplished by the permittee
sending a notice about the temporary authorization to all persons on the facility mailing list and to
appropriate state and local governments. See regulations at 40 CFR 270.42, promulgated on
September 28, 1988, and associated preamble at 53 FR 37919.
Regulations and Policies that Apply to Contaminated Environmental Media Only
Contained-in policy. Contaminated environmental media, of itself, is not hazardous
waste and, generally, is not subject to regulation under RCRA. Contaminated environmental
media can become subject to regulation under RCRA if they "contain" hazardous waste. As
discussed more fully below, EPA generally considers contaminated environmental media to
contain hazardous waste: (1) when they exhibit a characteristic of hazardous waste; or, (2) when
they are contaminated with concentrations of hazardous constituents from listed hazardous waste
that are above health-based levels.
If contaminated environmental media contain hazardous waste, they are subject to all
applicable RCRA requirements until they no longer contain hazardous waste. EPA considers
-------
contaminated environmental media to no longer contain hazardous waste: (1) when they no
longer exhibit a characteristic of hazardous waste; and (2) when concentrations of hazardous
constituents from listed hazardous wastes are below health-based levels. Generally, contaminated
environmental media that do not (or no longer) contain hazardous waste are not subject to any
RCRA requirements; however, as discussed below, in some circumstances, contaminated
environmental media that contained hazardous waste when first generated (i.e., first removed
from the land, or area of contamination) remain subject to LDR treatment requirements even after
they "no longer contain" hazardous waste.
The determination that any given volume of contaminated media does not contain
hazardous waste is called a "contained-in determination." In the case of media that exhibit a
characteristic of hazardous waste, the media are considered to "contain" hazardous waste for as
long as they exhibit a characteristic. Once the characteristic is eliminated (e.g., through
treatment), the media are no longer considered to "contain" hazardous waste. Since this
determination can be made through relatively straightforward analytical testing, no formal
"contained-in" determination by EPA or an authorized state is required. Just like determinations
about whether waste has been adequately decharacterized, generators of contaminated media may
make independent determinations as to whether the media exhibit a characteristic of hazardous
waste. In the case of media that are contaminated by listed hazardous waste, current EPA
guidance recommends that contained-in determinations be made based on direct exposure using a
reasonable maximum exposure scenario and that conservative, health-based, standards be used to
develop the site-specific health-based levels of hazardous constituents below which contaminated
environmental media would be considered to no longer contain hazardous waste. Since this
determination involves development of site-specific health-based levels, the approval of EPA or
an authorized state is required.
In certain circumstances the, RCRA land disposal restrictions will continue to apply to
contaminated media that has been determined not to contain hazardous waste. This is the case
when contaminated media contain hazardous waste when they are first generated (i.e., removed
from the land, or area of contamination) and are subsequently determined to no longer contain
hazardous waste (e.g., after treatment), but still contain hazardous constituents at concentrations
above land disposal restriction treatment standards. It is also the case when media are
contaminated as a result of disposal of untreated (or insufficiently treated) listed hazardous waste
after the effective date of an applicable LDR treatment requirement. Of course, if no land
disposal will occur (e.g., the media will be legitimately recycled) the LDR treatment standards do
not apply. In addition, contaminated environmental media determined not to contain any waste
(i.e., it is just media, it does not contain solid or hazardous waste) would not be subject to any
RCRA Subtitle C requirements, including the LDRs, regardless of the time of the "contained-in"
determination.
The contained-in policy was first articulated in a November 13, 1986 EPA memorandum,
"RCRA Regulatory Status of Contaminated Groundwater." It has been updated many times in
Federal Register preambles, EPA memos and correspondence, see, e.g., 53 FR 31138, 31142,
31148 (Aug. 17, 1988), 57 FR 21450, 21453 (May 20, 1992), and detailed discussion in HWIR-
Media proposal preamble, 61 FR 18795 (April 29, 1996). A detailed discussion of the continuing
requirement that some soils which have been determined to no longer contain hazardous waste
(but still contain solid waste) comply with land disposal treatment standards can be found in the
10
-------
HWIR-Media proposal preamble, 61 FR 18804; the September 15, 1996 letter from Michael
Shapiro (EPA OSW Director) to Peter C. Wright (Monsanto Company); and the preamble to the
LDR Phase IV rule, 63 FR 28617 (May 26, 1998).
Note that the contained-in policy applies only to environmental media (soil, ground water,
surface water and sediments) and debris. The contained-in policy for environmental media has
not been codified. As discussed below, the contained-in policy for hazardous debris was codified
in 1992.
RCRA Section 3020(b) Exemption for Reinjection of Contaminated Ground Water.
Under RCRA Section 3020(a), disposal of hazardous waste into or above a formation that
contains an underground source of drinking water is generally prohibited. RCRA Section 3020(b)
provides an exception for underground injection carried out in connection with certain
remediation activities. Under RCRA Section 3020(b), injection of contaminated ground water
back into the aquifer from which it was withdrawn is allowed if: (1) such injection is conducted as
part of a response action under Section 104 or 106 of CERCLA or a RCRA corrective action
intended to clean up such contamination; (2) the contaminated ground water is treated to
substantially reduce hazardous constituents prior to reinjection; and, (3) the response action or
corrective action will, on completion, be sufficient to protect human health and the environment.
Approval of reinjection under RCRA Section 3020(b) can be included in approval of other
cleanup activities, for example, as part of approval of a RCRA Statement of Basis or CERCLA
Record of Decision. See, RCRA Section 3020(b), established as part of the 1984 HSWA
amendments. See also, OSWER Directive 9234.1-06, "Applicable of Land Disposal Restrictions
to RCRA and CERCLA Ground Water Treatment Reinjection Superfund Management Review:
Recommendation No. 26," November 27, 1989.
LDR Treatment Standards for Contaminated Soils. On May 26, 1998, EPA
promulgated land disposal restriction treatment standards specific to contaminated soils.3 These
treatment standards require that contaminated soils which will be land disposed be treated to
reduce concentrations of hazardous constituents by 90 percent or meet hazardous constituent
concentrations that are ten times the universal treatment standards (UTS), whichever is greater.
(This is typically referred to as 90% capped by lOxUTS.) For contaminated soil that exhibits a
characteristic of ignitable, reactive or corrosive hazardous waste, treatment must also eliminate
the hazardous characteristic.
The soil treatment standards apply to all underlying hazardous constituents4 reasonably
expected to be present in any given volume of contaminated soil when such constituents are found
at initial concentrations greater than ten times the UTS. For soil that exhibits a characteristic of
toxic, ignitable, reactive or corrosive hazardous waste, treatment is also required for: (1) in the
case of the toxicity characteristic, the characteristic constituent; and, (2) in the case of ignitability,
This rule, which also addresses a number of non-soil issues, has been challenged by a number of parties. To
date, the parties have filed non-binding statements of issues only; however, based on those statements, it appears that, with
the exception of the requirement that PCBs be included as an underlying hazardous constituent which has been challenged
for both soil and non-soil wastes, the soil treatment standards are not included in the challenges.
Except fluoride, selenium, sulfides, vanadium and zinc.
11
-------
reactivity or corrosivity, the characteristic property. Although treatment is required for each
underlying hazardous constituent, it is not necessary to monitor soil for the entire list of
underlying hazardous constituents. Generators of contaminated soil can reasonably apply
knowledge of the likely contaminants present and use that knowledge to select appropriate
underlying hazardous constituents, or classes of constituents, for monitoring. As with the LDR
treatment standards for hazardous debris (discussed below), generators of contaminated soil may
use either the applicable universal treatment standards for the contaminating hazardous waste or
the soil treatment standards.
See, soil treatment standard regulations at 40 CFR 268.49, promulgated May 26, 1998
and associated preamble discussion at 63 FR 28602-28622.
Note that the soil treatment standards supersede the historic presumption that an LDR
treatment variance is appropriate for contaminated soil. LDR treatment variances are still
available for contaminated soil, provided the generator can show that an otherwise applicable
treatment standard (i.e., the soil treatment standard) is unachieveable or inappropriate, as
discussed above, or can show that a site-specific, risk-based treatment variance is proper, as
discussed below.
Site-Specific, Risk-Based LDR Treatment Variance for Contaminated Soils. On
May 26, 1998, EPA promulgated a new land disposal restriction treatment variance specific to
contaminated soil. Under 40 CFR 268.44(h)(3), variances from otherwise applicable LDR
treatment standards may be approved if it is determined that compliance with the treatment
standards would result in treatment beyond the point at which short- and long-term threats to
human health and the environment are minimized. This allows a site-specific, risk-based
determination to supersede the technology-based LDR treatment standards under certain
circumstances.
Alternative land disposal restriction treatment standards established through site specific,
risk-based minimize threat variances should be within the range of values the Agency generally
finds acceptable for risk-based cleanup levels. That is, for carcinogens, alternative treatment
standards should ensure constituent concentrations that result in the total excess risk to an
individual exposed over a lifetime generally falling within a range from 10~4 to 10'6, using 10'6 as a
point of departure and with a preference for achieving the more protective end of the risk range.
For non-carcinogenic effects, alternative treatment standards should ensure constituent
concentrations that an individual could be exposed to on a daily basis without appreciable risk of
deleterious effect during a lifetime; in general, the hazard index should not exceed one (1).
Constituent concentrations that achieve these levels should be calculated based on a reasonable
maximum exposure scenario that is, based on an analysis of both the current and reasonable
expected future land uses, with exposure parameters chosen based on a reasonable assessment of
the maximum exposure that might occur; however, alternative LDR treatment standards may not
be based on consideration of post-land disposal controls such as caps or other barriers.
See, regulations at 40 CFR 268.44(h)(4), promulgated May 26, 1998 and associated
preamble discussion at 63 FR 28606-28608.
Regulations and Policies that Apply Only to Debris
12
-------
LDR Treatment Standards for Contaminated Debris. In 1992, EPA established land
disposal restriction treatment standards specific to hazardous contaminated debris. The debris-
specific treatment standards established by these regulations are based on application of common
extraction, destruction, and containment debris treatment technologies and are expressed as
specific technologies rather than numeric criteria. As with the contaminated soil treatment
standards discussed earlier, generators of hazardous contaminated debris may choose between
meeting either the debris treatment standards or the numerical treatment standard promulgated for
the contaminating hazardous waste. See, regulations at 40 CFR 268.45, promulgated August 18,
1992, and associated preamble discussion at 57 FR 37194 and 27221.
Interpretation that Debris Treated to the LDR Debris Treatment Standards Using
Extraction or Destruction Technologies no Longer Contain Hazardous Waste. With the
land disposal restriction treatment standards for hazardous contaminated debris, in 1992, EPA
determined that hazardous debris treated to comply with the debris treatment standards using one
of the identified extraction or destruction technologies would be considered no longer to contain
hazardous waste and would, therefore, no longer be subject to regulation under RCRA, provided
the debris do not exhibit any of the hazardous waste characteristics. This "contained-in
determination" is automatic; no agency action is needed. Note that this automatic contained-in
determination does not apply to debris treated to the debris treatment standards using one of the
identified immobilization technologies. See, regulations at 40 CFR 261.3(f) and treatment
standards at Table 1 of 40 CFR 268.45, promulgated August 18, 1992, and associated preamble
discussion at 51 FR 37225.
cc: Barbara Simcoe, Association of State and Territorial Solid Waste Management Officials
13
-------
APPENDIX B:
STATISTICAL TABLES
Interim Guidance September 2001
-------
Table B-1: 10% Values For The Nonparametric Test of Location
nv\nT
2345
10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47
50
1
2
3
4
5
6
7
8
9
11
13
15
17
19
21
23
25
27
29
31
33
35
37
39
41
43
45
47
49
50
2
2
2
2
2
2
1 2
1 2
1 2
1 2
1 2
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
3
3
3
3
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
9
4
4
3
3
3
3
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
9
5
4
4
3
3
3
3
3
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
9
6
5
4
4
3
3
3
3
3
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
9
6
5
5
4
4
3
3
3
3
3
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
9
7
6
5
4
4
4
4
3
3
3
3
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
9
9
8
6
5
5
4
4
4
4
3
3
3
3
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
9
10
8
7
6
5
5
4
4
4
3
3
3
3
3
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
9
11
3
7
6
6
5
5
4
4
4
3
3
3
3
3
2
2
2
2
2
2
2
2
2
2
2
2
2
2
9
12
10
8
7
6
5
5
5
4
4
3
3
3
3
3
3
2
2
2
2
2
2
2
2
2
2
2
2
2
9
13
10
9
7
6
6
5
5
4
4
4
3
3
3
3
3
3
3
2
2
2
2
2
2
2
2
2
2
2
9
14
11
9
8
7
6
5
5
5
4
4
3
3
3
3
3
3
3
3
2
2
2
2
2
2
2
2
2
2
9
15
12
10
8
7
6
6
5
5
4
4
4
3
3
3
3
3
3
3
3
2
2
2
2
2
2
2
2
2
9
16
12
10
3
7
7
6
6
5
5
4
4
4
3
3
3
3
3
3
3
3
2
2
2
2
2
2
2
2
9
17
13
11
3
8
7
6
6
5
5
4
4
4
3
3
3
3
3
3
3
3
3
2
2
2
2
2
2
2
9
18
14
11
3
8
7
7
6
6
5
4
4
4
4
3
3
3
3
3
3
3
3
3
2
2
2
2
2
2
9
19
15
12
10
9
8
7
6
6
5
5
4
4
4
3
3
3
3
3
3
3
3
3
3
2
2
2
2
2
9
19
15
12
10
9
8
7
7
6
5
5
4
4
4
4
3
3
3
3
3
3
3
3
3
3
2
2
2
2
9
20
16
13
11
9
8
7
7
6
6
5
5
4
4
4
4
3
3
3
3
3
3
3
3
3
3
2
2
2
9
21
17
13
11
10
9
8
7
7
6
5
5
4
4
4
4
3
3
3
3
3
3
3
3
3
3
3
2
2
9
22
17
14
12
10
3
8
7
7
6
5
5
4
4
4
4
4
3
3
3
3
3
3
3
3
3
3
3
2
7
23
18
14
12
10
3
8
8
7
6
5
5
5
4
4
4
4
3
3
3
3
3
3
3
3
3
3
3
3
3
24
19
15
13
11
10
9
8
7
6
6
5
5
4
4
4
4
4
3
3
3
3
3
3
3
3
3
3
3
3
25
19
15
13
11
10
9
8
7
6
6
5
5
5
4
4
4
4
3
3
3
3
3
3
3
3
3
3
3
3
26
20
16
13
12
10
9
8
8
7
6
5
5
5
4
4
4
4
4
3
3
3
3
3
3
3
3
3
3
3
27
21
17
14
12
11
9
9
8
7
6
6
5
5
4
4
4
4
4
4
3
3
3
3
3
3
3
3
3
3
28
21
17
14
12
11
10
3
8
7
6
6
5
5
5
4
4
4
4
4
3
3
3
3
3
3
3
3
3
3
28
22
18
15
13
11
10
3
8
7
6
6
5
5
5
4
4
4
4
4
4
3
3
3
3
3
3
3
3
3
29
23
18
15
13
11
10
3
9
7
7
6
5
5
5
4
4
4
4
4
4
3
3
3
3
3
3
3
3
3
30
23
19
16
13
12
11
10
9
8
7
6
6
5
5
5
4
4
4
4
4
4
3
3
3
3
3
3
3
3
31
24
19
16
14
12
11
10
9
8
7
6
6
5
5
5
4
4
4
4
4
4
3
3
3
3
3
3
3
3
32
25
20
16
14
12
11
10
9
8
7
6
6
5
5
5
5
4
4
4
4
4
4
3
3
3
3
3
3
3
33
25
20
17
14
13
11
10
9
8
7
7
6
6
5
5
5
4
4
4
4
4
4
4
3
3
3
3
3
3
34
26
21
17
15
13
12
11
10
8
7
7
6
6
5
5
5
4
4
4
4
4
4
4
3
3
3
3
3
3
35
27
21
18
15
13
12
11
10
9
8
7
6
6
5
5
5
5
4
4
4
4
4
4
4
3
3
3
3
3
36
28
22
18
16
14
12
11
10
9
8
7
6
6
6
5
5
5
4
4
4
4
4
4
4
3
3
3
3
3
37
28
22
19
16
14
13
11
10
9
8
7
7
6
6
5
5
5
5
4
4
4
4
4
4
4
3
3
3
3
37
29
23
19
16
14
13
12
11
9
8
7
7
6
6
5
5
5
5
4
4
4
4
4
4
4
4
3
3
3
38
30
24
20
17
15
13
12
11
9
8
7
7
6
6
5
5
5
5
4
4
4
4
4
4
4
4
3
3
3
39
30
24
20
17
15
13
12
11
10
8
8
7
6
6
6
5
5
5
5
4
4
4
4
4
4
4
4
3
3
40
31
25
20
17
15
14
12
11
10
9
8
7
6
6
6
5
5
5
5
4
4
4
4
4
4
4
4
3
3
41
32
25
21
18
16
14
13
12
10
9
8
7
7
6
6
5
5
5
5
5
4
4
4
4
4
4
4
4
3
42
32
26
21
18
16
14
13
12
10
9
8
7
7
6
6
6
5
5
5
5
4
4
4
4
4
4
4
4
43
33
26
22
19
16
14
13
12
10
9
8
7
7
6
6
6
5
5
5
5
4
4
4
4
4
4
4
4
44
34
27
22
19
17
15
13
12
10
9
8
8
7
6
6
6
5
5
5
5
5
4
4
4
4
4
4
4
45
34
27
23
19
17
15
14
12
11
9
8
8
7
7
6
6
5
5
5
5
5
4
4
4
4
4
4
4
46
35
28
23
20
17
15
14
13
11
10
9
8
7
7
6
6
6
5
5
5
5
4
4
4
4
4
4
4
46
36
28
23
20
18
16
14
13
11
10
9
8
7
7
6
6
6
5
5
5
5
5
4
4
4
4
4
4
-------
Table B-2: 5% Values For The Nonparametric Test of Location
«[/\ flT 1 2 3 4 5 6 7 8 91011121314151617 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45
47 48 49 50
1
2
3
4
5
6
7
8
9
10
11
12
14
16
18
20
22
24
26
28
30
32
34
36
38
40
42
44
45
47
49
50
2
2
2
2
2
2
2
2
2
2
2
1 2
1 2
1 2
1 2
1 2
1 2
1 2
1 2
1 2
1 2
1 1
1 1
1 1
1 1
1 1
1 1
1 1
3
3
3
3
3
3
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
9
4
4
3
3
3
3
3
3
3
3
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
9
5
5
4
4
4
3
3
3
3
3
3
3
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
7
6
5
5
4
4
4
4
3
3
3
3
3
3
3
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
9
7
6
5
5
4
4
4
4
4
3
3
3
3
3
3
3
2
2
2
2
2
2
2
2
2
2
2
2
2
2
9
8
7
6
5
5
5
4
4
4
4
3
3
3
3
3
3
3
2
2
2
2
2
2
2
2
2
2
2
2
2
9
9
7
6
6
5
5
5
4
4
4
4
3
3
3
3
3
3
3
3
2
2
2
2
2
2
2
2
2
2
2
9
9
8
7
6
6
5
5
5
4
4
4
4
3
3
3
3
3
3
3
3
3
2
2
2
2
2
2
2
2
2
7
10
9
8
7
6
6
5
5
5
4
4
4
4
3
3
3
3
3
3
3
3
3
3
2
2
2
2
2
2
2
9
11
9
8
7
6
6
6
5
5
5
4
4
4
4
3
3
3
3
3
3
3
3
3
3
2
2
2
2
2
2
9
12
10
9
8
7
6
6
5
5
5
5
4
4
4
4
3
3
3
3
3
3
3
3
3
3
3
2
2
2
2
9
13
11
9
8
7
7
6
6
5
5
5
4
4
4
4
4
3
3
3
3
3
3
3
3
3
3
3
3
2
2
7
13
11
10
9
8
7
6
6
6
5
5
5
4
4
4
4
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
14
12
10
9
8
7
7
6
6
6
5
5
5
4
4
4
4
3
3
3
3
3
3
3
3
3
3
3
3
3
3
15
12
11
9
8
8
7
7
6
6
6
5
5
4
4
4
4
4
3
3
3
3
3
3
3
3
3
3
3
3
3
16
13
11
10
9
8
7
7
6
6
6
5
5
5
4
4
4
4
4
3
3
3
3
3
3
3
3
3
3
3
3
16
14
12
10
9
8
8
7
7
6
6
5
5
5
4
4
4
4
4
4
3
3
3
3
3
3
3
3
3
3
3
20
17
14
12
11
10
9
8
7
7
7
6
6
5
5
5
4
4
4
4
4
4
3
3
3
3
3
3
3
3
3
3
21
18
15
13
11
10
9
8
8
7
7
6
6
5
5
5
4
4
4
4
4
4
4
3
3
3
3
3
3
3
3
3
22
19
16
13
12
10
9
9
8
8
7
7
6
6
5
5
5
4
4
4
4
4
4
3
3
3
3
3
3
3
3
3
23
20
16
14
12
11
10
9
8
8
7
7
6
6
5
5
5
4
4
4
4
4
4
4
3
3
3
3
3
3
3
3
24
20
17
14
13
11
10
9
9
8
8
7
6
6
5
5
5
5
4
4
4
4
4
4
4
3
3
3
3
3
3
3
25
21
18
15
13
12
11
10
9
8
8
7
7
6
6
5
5
5
5
4
4
4
4
4
4
4
3
3
3
3
3
3
26
22
18
15
14
12
11
10
9
9
8
8
7
6
6
5
5
5
5
4
4
4
4
4
4
4
4
3
3
3
3
3
27
23
19
16
14
12
11
10
9
9
8
8
7
6
6
6
5
5
5
5
4
4
4
4
4
4
4
4
3
3
3
3
28
23
19
17
14
13
12
11
10
9
9
8
7
7
6
6
5
5
5
5
4
4
4
4
4
4
4
4
4
3
3
3
29
24
20
17
15
13
12
11
10
9
9
8
7
7
6
6
6
5
5
5
5
4
4
4
4
4
4
4
4
4
3
3
30
25
21
18
15
14
12
11
10
10
9
8
8
7
6
6
6
5
5
5
5
4
4
4
4
4
4
4
4
4
4
3
31
26
21
18
16
14
13
12
11
10
9
9
8
7
7
6
6
5
5
5
5
5
4
4
4
4
4
4
4
4
4
32
26
22
19
16
14
13
12
11
10
9
9
8
7
7
6
6
6
5
5
5
5
4
4
4
4
4
4
4
4
4
33
27
23
19
17
15
13
12
11
10
10
9
8
7
7
6
6
6
5
5
5
5
5
4
4
4
4
4
4
4
4
34
28
23
20
17
15
14
12
11
11
10
9
8
8
7
7
6
6
6
5
5
5
5
5
4
4
4
4
4
4
4
35
29
24
20
18
16
14
13
12
11
10
10
9
8
7
7
6
6
6
5
5
5
5
5
4
4
4
4
4
4
4
36
30
24
21
18
16
14
13
12
11
10
10
9
8
7
7
6
6
6
5
5
5
5
5
5
4
4
4
4
4
4
37
30
25
21
18
16
15
13
12
11
11
10
9
8
8
7
7
6
6
6
5
5
5
5
5
4
4
4
4
4
4
38
31
26
22
19
17
15
14
13
12
11
10
9
8
8
7
7
6
6
6
5
5
5
5
5
5
4
4
4
4
4
39
32
26
22
19
17
15
14
13
12
11
10
9
9
8
7
7
6
6
6
6
5
5
5
5
5
4
4
4
4
4
39
33
27
23
20
18
16
14
13
12
11
11
10
9
8
7
7
7
6
6
6
5
5
5
5
5
5
4
4
4
4
40
33
28
23
20
18
16
15
13
12
12
11
10
9
8
8
7
7
6
6
6
5
5
5
5
5
5
5
4
4
4
41
34
28
24
21
18
16
15
14
13
12
11
10
9
8
8
7
7
6
6
6
6
5
5
5
5
5
5
5
4
4
42
35
29
24
21
19
17
15
14
13
12
11
10
9
8
8
7
7
7
6
6
6
5
5
5
5
5
5
5
4
4
43
36
30
25
22
19
17
16
14
13
12
12
10
9
9
8
7
7
7
6
6
6
6
5
5
5
5
5
5
5
4
44
37
30
26
22
20
18
16
15
14
13
12
11
10
9
8
8
7
7
6
6
6
6
5
5
5
5
5
5
5
4
45
37
31
26
23
20
18
16
15
14
13
12
11
10
9
8
8
7
7
7
6
6
6
6
5
5
5
5
5
5
5
46
38
31
27
23
20
18
17
15
14
13
12
11
10
9
8
8
7
7
7
6
6
6
6
5
5
5
5
5
5
5
5
47 48 49
39 40 40
32 33 33
27 28 28
23 24 24
21 21 21
19 19 19
17 17 17
15 16 16
14 15 15
13 14 14
12 13 13
11 11 12
10 10 10
9 9 10
999
888
788
111
111
677
666
666
666
566
555
555
555
555
555
555
555
-------
Table B-3. Critical Values of Student's t Distribution (One-Tailed)
Degrees
of
Freedom
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
40
60
120
oo
1--
0.80
1.376
1.061
0.978
0.941
0.920
0.906
0.896
0.889
0.883
0.879
0.876
0.873
0.870
0.868
0.866
0.865
0.863
0.862
0.861
0.860
0.859
0.858
0.858
0.857
0.856
0.856
0.855
0.855
0.854
0.854
0.851
0.848
0.845
0.842
0.85
1.963
1.386
1.250
1.190
1.156
1.134
1.119
1.108
1.100
1.093
1.088
1.083
1.079
1.076
1.074
1.071
1.069
1.067
1.066
1.064
1.063
1.061
1.060
1.059
1.058
1.058
1.057
1.056
1.055
1.055
1.050
1.046
1.041
1.036
0.90
3.078
1.886
1.638
1.533
1.476
1.440
1.415
1.397
1.383
1.372
1.363
1.356
1.350
1.345
1.340
1.337
1.333
1.330
1.328
1.325
1.323
1.321
1.319
1.318
1.316
1.315
1.314
1.313
1.311
1.310
1.303
1.296
1.289
1.282
0.95
6.314
2.920
2.353
2.132
2.015
1.943
1.895
1.860
1.833
1.812
1.796
1.782
1.771
1.761
1.753
1.746
1.740
1.734
1.729
1.725
1.721
1.717
1.714
1.711
1.708
1.706
1.703
1.701
1.699
1.697
1.684
1.671
1.658
1.645
0.99
31.821
6.965
4.541
3.747
3.365
3.143
2.998
2.896
2.821
2.764
2.718
2.681
2.650
2.624
2.602
2.583
2.567
2.552
2.539
2.528
2.518
2.508
2.500
2.492
2.485
2.479
2.473
2.467
2.462
2.457
2.423
2.390
2.358
2.326
-------
Table B-4. Critical Values For the Wilcoxon Rank Sum Test
"r
2
3
4
5
6
7
8
9
10
11
12
13
14
15
a
0.05
0.10
0.05
0.10
0.05
0.10
0.05
0.10
0.05
0.10
0.05
0.10
0.05
0.10
0.05
0.10
0.05
0.10
0.05
0.10
0.05
0.10
0.05
0.10
0.05
0.10
0.05
0.10
nre1
2
0
0
0
1
0
1
1
2
1
2
1
2
2
3
2
3
2
4
2
4
3
5
3
5
4
5
4
6
3
0
1
1
2
1
2
2
3
3
4
3
5
4
6
5
6
5
7
6
8
6
9
7
10
8
11
8
11
4
0
1
2
2
2
4
3
5
4
6
5
7
6
8
7
10
8
11
9
12
10
13
11
14
12
16
13
17
5
1
2
2
3
3
5
5
6
6
8
7
9
9
11
10
13
12
14
13
16
14
18
16
19
17
21
19
23
6
1
2
3
4
4
6
6
8
8
10
9
12
11
14
13
16
15
18
17
20
18
22
20
24
22
26
24
28
7
1
2
3
5
5
7
7
9
9
12
12
14
14
17
16
19
18
22
20
24
22
27
25
29
27
32
29
34
8
2
3
4
6
6
8
9
11
11
14
14
17
16
20
19
23
21
25
24
28
27
31
29
34
32
37
34
40
9
2
3
5
6
7
10
10
13
13
16
16
19
19
23
22
26
25
29
28
32
31
36
34
39
37
42
40
46
10
2
4
5
7
8
11
12
14
15
18
18
22
21
25
25
29
28
33
32
37
35
40
38
44
42
48
45
52
11
2
4
6
8
9
12
13
16
17
20
20
24
24
28
28
32
32
37
35
41
39
45
43
49
47
53
51
58
12
3
5
6
9
10
13
14
18
18
22
22
27
27
31
31
36
35
40
39
45
43
50
48
54
52
59
56
64
13
3
5
7
10
11
14
16
19
20
24
25
29
29
34
34
39
38
44
43
49
48
54
52
59
57
64
62
69
14
4
5
8
11
12
16
17
21
22
26
27
32
32
37
37
42
42
48
47
53
52
59
57
64
62
70
67
75
15
4
6
8
11
13
17
19
23
24
28
29
34
34
40
40
46
45
52
51
58
56
64
62
69
67
75
73
81
16
4
6
9
12
15
18
20
24
26
30
31
37
37
43
43
49
49
55
55
62
61
68
66
75
72
81
78
87
17
4
7
10
13
16
19
21
26
27
32
34
39
40
46
46
53
52
59
58
66
65
73
71
80
78
86
84
93
18
5
7
10
14
17
21
23
28
29
35
36
42
42
49
49
56
56
63
62
70
69
78
76
85
83
92
89
99
19
5
8
11
15
18
22
24
29
31
37
38
44
45
52
52
59
59
67
66
74
73
82
81
90
88
98
95
105
20
5
8
12
16
19
23
26
31
33
39
40
47
48
55
55
63
63
71
70
79
78
87
85
95
93
103
101
111
-------
Table B-4. Critical Values For the Wilcoxon Rank Sum Test (continued)
"r
16
17
18
19
20
a
0.05
0.10
0.05
0.10
0.05
0.10
0.05
0.10
0.05
0.10
nre1
2
4
6
4
7
5
7
5
8
5
8
3
9
12
10
13
10
14
11
15
12
16
4
15
18
16
19
17
21
18
22
19
23
5
20
24
21
26
23
28
24
29
26
31
6
26
30
27
32
29
35
31
37
33
39
7
31
37
34
39
36
42
38
44
40
47
8
37
43
40
46
42
49
45
52
48
55
9
43
49
46
53
49
56
52
59
55
63
10
49
55
52
59
56
63
59
67
63
71
11
55
62
58
66
62
70
66
74
70
79
12
61
68
65
73
69
78
73
82
78
87
13
66
75
71
80
76
85
81
90
85
95
14
72
81
78
86
83
92
88
98
93
103
15
78
87
84
93
89
99
95
105
101
111
16
84
94
90
100
96
107
102
113
108
120
17
90
100
97
107
103
114
110
121
116
128
18
96
107
103
114
110
121
117
129
124
136
19
102
113
110
121
117
129
124
136
131
144
20
108
120
116
128
124
136
131
144
139
152
------- |