GUIDANCE FOR
METHODS DEVELOPMENT
         AND
 METHODS VALIDATION
       FOR THE
    RCRA PROGRAM

-------
                           PREFACE AND OVERVIEW
      Test Methods for Evaluating Solid Waste, or SW-846, is the compendium of analytical
and test methods approved by EPA's Office of Solid Waste (OSW) for use in determining
regulatory compliance under the Resource Conservation and Recovery Act (RCRA). SW-846
functions primarily as a guidance document setting forth acceptable, although not required,
methods to be implemented by the user, as appropriate, in responding to RCRA-related
sampling and analysis requirements.

      There seems to  be an impression among methods developers and the regulated
community that there is some esoteric or mystical process that must be followed in order to get
an analytical method "approved" by regulatory agencies like the USEPA. In this document,
OSW would like to dispel these misconceptions, identify some basic principles,  and present a
logical approach to methods development that is currently followed by OSW  in developing
methods for SW-846.  This approach is based on sound scientific principles, and methods
developed according to this process should be acceptable for use in other Agency programs as
well as OSW.

      Two levels of methods development are covered in this guidance document, initial
"proof of concept" and a formal validation. This guidance is applicable to both new methods
submitted for potential inclusion in SW-846 or for adapting existing SW-846 methods for
additional applications. When measurements for RCRA applications are required for which
no validated methods exist, e.g., from unusual matrices or below the quantitation limits of
conventional SW-846 or other appropriate methods, qualified analysts can serve as "in-house"
methods developers to modify existing methods to meet these  regulatory needs following the
guidelines delineated in Elements 1 through 9.

      The RCRA method development approach utilizes three basic  principles for either
demonstrating "proof of concept" or for use in a formal validation.  These basic scientific
principles are:

      1)     Identify the  scope  and application of the proposed method, (What is this
             method supposed to accomplish?)

      2)     Develop a procedure that will generate data that are consistent with  the
             intended scope and application of the method, and

      3)     Establish appropriate quality control procedures which will ensure that when
             the proposed procedure is followed, the method will generate the appropriate
             data from  Step 2 that will meet the criteria established in Step 1.

      In some cases, such as a variation of an existing SW-846 method using new equipment
or a modified procedure, it is  sufficient only to demonstrate validation  to the "proof of
concept" stage. For new  technologies to be considered for inclusion in SW-846,  it is necessary
for the developer to perform the formal validation procedure including multilaboratory
validation.

-------
   DEVELOPMENT AND
     VALIDATION OF
    SW-846 METHODS
        PHASE 1:
PRELIMINARY VALIDATION
          OR
   DEMONSTRATION OF
  "PROOF OF CONCEPT"

-------
            DEVELOPMENT AND VALIDATION OF SW-846 METHODS
       PHASE 1: PRELIMINARY VALIDATION OR "PROOF OF CONCEPT"

      The two documents included in this section are letters that were requested by potential
methods developers on how to begin a methods development project for submission to OSW
for inclusion in SW-846. One letter (dated April 6,1992) addresses a preliminary validation
or "proof of concept" for new sample preparation methods, while the other (dated April 23,
1992) addresses a preliminary validation or "proof of concept" for new screening methods.

      A shortened list of target analytes, representative of typical RCRA analyte classes for
volatile organics, semivolatile organics, pesticides, and metals were included. These target
analyte lists provide a range of target analyte performance within existing methods. The idea
in this preliminary stage was that if the potential new method could successfully analyze the
target analyte lists included in these documents, it had potential applicability to successfully
analyze the compounds on the extended RCRA target analyte lists. These guidance documents
also recommend using multiple matrices, e.g., groundwater, TCLP leachate, and wastewater
for aqueous  matrices,  sand, loam, and  clay for  soil  matrices, and multiple spiking
concentrations to demonstrate appropriate method performance.

      If a new technique performs adequately in this "proof of concept" phase, it is ready for
the formal validation process. In this way, by doing a preliminary  method development
screening, the developer can easily determine if it is worth continuing to invest in  a project
without a large outlay of time or money.

      In some cases, e.g., development of alternative equipment for an existing method, this
preliminary  validation  may be  all that  is necessary  to demonstrate adequate method
performance for the intended method application.

-------
April 6, 1992

Dear Colleague:

       The Methods Team of the Office of Solid Waste is responsible for the promulgation of
rugged and  reliable analytical techniques in support  of the Resource Conservation  and
Recovery Act (RCRA) program. The methods published in Test Methods for Evaluating Solid
Waste, SW-846, are used to measure the concentration of specific pollutants or to establish
whether a waste stream demonstrates a hazardous characteristic (e.g. ignitability, corrosivity,
reactivity or toxicity).

       A number of sources have developed new methods for preparing samples that could
have application for the RCRA program. The U.S. EPA is eager to adopt any new techniques
that provide high quality data in a reliable, reproducible and cost-effective manner. This letter
provides developers with a description of the type of performance data that is required for an
effective initial evaluation of new SW-846 methods. If a developer's data supports adoption
of a new method, the Methods Team will work through the SW-846 Work Group process to
promulgate  it. This letter does not supersede or replace the more rigorous requirements
described  in Test  Method  Equivalency Petitions.  EPA/530-SW-87-008, OSWER Policy
Directive No. 9433.00-2  (2/87).  That document provides the  requirements  for a method
equivalency  petition which may be used to promulgate a method outside of the Work Group
process.

       In order to evaluate the performance of sample preparation procedures, data should
be submitted for samples prepared  using the proposed technique,  and analyzed using
approved  SW-846  quantitative methods. Widely used, multi-analyte procedures such as
Method 8270  (GC/MS  for  semi-volatiles),  Method 8081  (GC/ECD for organochlorine
insecticides), Method 8260 (GC/MS for volatiles), or Method 6010 (ICP/AES for metals) should
generally be employed. New sample preparation techniques need not be validated for the
entire target list of a multi-analyte method, but a representative selection of targets should be
measured. Examples of representative target analytes and some of the rationale for selecting
them are provided  in the attachments.

       Developers should analyze three different types of matrices. Samples that are analyzed
should either be characterized reference materials or spiked matrices containing known
amounts of target analytes.  In either case, bulk samples should be carefully homogenized to
reduce sub-sampling errors.  The sample matrices should be selected  to represent what is
regulated  under RCRA  (e.g. soil, oily waste or waste waters), not  to  provide the  best
performance data.  Blanks should be analyzed with each set of samples.

       Method performance is established by analyzing seven replicate  aliquots of three
different sample matrices spiked at two concentrations.  Suggested spiking levels are 5 times
the lower quantitation limit  for the preparation/analysis  method and 50 times  the  low
concentration. As an alternative, specific concentrations for selected target analytes in soil are

                                         5

-------
provided in the attachments to this letter. The low values are normal reporting limits for
routine analyses and the high value is 50 times the low.  Recovery, precision, and matrix
method detection level must be calculated.  Method bias (accuracy) is determined at both
concentrations by calculating the mean recovery of the spiked (or characterized) analytes for
the seven replicates.

                          bias =   x    x  100%
                                  X

             x = Mean value for the seven replicate determinations

             X = Spiked or characterized concentration

Method precision is determined by calculating the percent relative standard deviation of the
spiked analyte recoveries for the seven replicates at each concentration.

                          precision = _s	 x 100%
                                      x
             x = Mean value for the seven replicate determinations

             s = Standard deviation for the seven replicates

       The U.S. EPA requires methods that provide  reliable measurements at or  below
regulatory action levels. The lowest level at which accurate quantitation can be attained must
be determined for each matrix. To determine the Reliable Quantitation Limit (RQL), the
Method Detection Limit (MDL) is first calculated from the low concentration s determined
from seven replicate measurements (six degrees of freedom):

                          MDL = 3.143 o

The RQL is calculated using the following equation:

                                   RQL = 4 MDL

       To summarize, the Methods Team  does not require an unreasonable body of data for
the initial evaluation of new techniques.  With the additional requirement of one blank per
matrix, 45 samples will have to be prepared and analyzed to complete the table below.

-------
Type of sample
Matrix 1, low
Matrix 1, high
Matrix 2, low
Matrix 2, high
Matrix 3, low
Matrix 3, high
bias






precision






MDL






RQL






      It is our belief that completion of this table represents only a small fraction of a
developer's effort in developing a new method.  If your technique will improve the quality of
EPA monitoring programs, submitting these data should expedite the SW-846 approval
process.

      I look forward to working with you on this important activity.

                                      Sincerely,
                                      Barry Lesnik
                                      Organic Methods Program Manager
                                      USEPA Office of Solid Waste
                                      Methods Team (5307W)
attachments

-------
              REPRESENTATIVE ORGANOCHLORINE PESTICIDES

      The following chlorinated pesticides from the Best Demonstrated Available Technology
(BDAT) list are representative of analytes for Method 8081. All should be sufficiently resolved
to ensure good  quantitation  using  two columns  such as the DB-608 or DB-1701 (or
equivalents).  Suggested low and high concentrations should be appropriate for relatively
uncontaminated solid matrices such as soil. Higher concentrations may be required for highly
contaminated samples.

COMPOUND                         LOW fug/kg)             HIGH fug/kg)

Aldrin                                5                        250
P-BHC                                5                        250
5-BHC                                5                        250
y-BHC (Lindane)                      5                        250
a-Chlordane                           5                        250
y-Chlordane                           5                        250
4,4'-DDD                              10                       500
4,4'-DDE                              5                        250
4,4'-DDT                              5                        250
Dieldrin                               5                        250
Endosulfan I                           5                        250
Endosulfan II                         5                        250
Endrin                                10                       500
Endrin aldehyde                       5                        250
Heptachlor                            5                        250
Heptachlor epoxide                     5                        250

-------
                REPRESENTATIVE SEMIVOLATILE COMPOUNDS

      The following compounds are representative of analytes for Method 8270. Although
many of these compounds are considered difficult, all can be extracted from waste matrices
using conventional techniques. Suggested low and high concentrations should be appropriate
for relatively uncontaminated solid matrices  such as soil. Higher  concentrations may be
required  for highly  contaminated samples. Phthalate esters are not spiked but should be
reported  as a measure of contamination.

 COMPOUND                         LOW fug/kg)             HIGH fug/kg)

Phenol                                250                      12,500
o-Cresol                               250                      12,500
2-Methyl phenol                       250                      12,500
2,4,6-Trichlorophenol                   250                      12,500
Pentachlorophenol                     250                      12,500
1,2-Dichlorobenzene                   250                      12,500
Naphthalene                           250                      12,500
2-Chloronaphthalene                   250                      12,500
Anthracene                            250                      12,500
Chrysene                             250                      12,500
Benzo(a)anthracene                    250                      12,500
Benzo(a)pyrene                        250                      12,500
Fluoranthene                          250                      12,500
Indeno(l,2,3-cd)pyrene                 250                      12,500
Benzo(g,h,i)perylene                   250                      12,500
o-Toluidine                            250                      12,500
p-Nitrotoluene                         250                      12,500
2,6-Dinitrotoluene                     250                      12,500
2-Nitroaniline                          250                      12,500
Di-n-propylnitrosamine                 250                      12,500
4-Bromophenyl phenyl ether            250                      12,500
3,3'-Dichlorobenzidine                 250                      12,500

In addition, surrogates should be added such that 50 //g or 100 //g would be present in final
extracts assuming 100% recovery.

Nitrobenzene-d5                  50
2-Fluorobiphenyl                 50
p-Terphenyl-d14                  50
Phenol-d6                       100
2-Fluorophenol                  100
2,4,6-Tribromophenol            100

-------
                  REPRESENTATIVE VOLATILE COMPOUNDS

      The following compounds are representative of analytes for Method 8260; many are
TCLP analytes.  All can be purged from waste matrices  using Methods 5030 or 5035.
Suggested low and high concentrations should be appropriate for relatively uncontaminated
solid matrices such as soil. Higher concentrations may be required for highly contaminated
samples.

 COMPOUND                         LOW fug/kg)             HIGH fug/kg)

Vinyl chloride                         5                        250
Dibromochloromethane                 5                        250
1,1-dichloroethane                     5                        250
Chloroform                            5                        250
Carbon tetrachloride                   5                        250
Trichloroethylene                      5                        250
1,1,1-Trichloroethane                   5                        250
Benzene                               5                        250
Toluene                               5                        250
Ethylbenzene                          5                        250
Chorobenzene                         5                        250
Nitrobenzene                          5                        250
Methyl ethyl ketone                    5                        250
Carbon disulfide                       5                        250

      The following compounds are representative of non-purgeable volatiles which currently
require azeotropic distillation. Suggested low and high concentrations should be appropriate
for relatively uncontaminated solid matrices such as soil.  Higher concentrations may be
required for highly contaminated samples.

 COMPOUND                         LOW fug/kg)             HIGH fug/kg)

1,4-Dioxane                            10                       500
n-Butanol                             10                       500
iso-butanol                            10                       500
Ethyl acetate                          10                       500
Pyridine                               10                       500
                                        10

-------
                          REPRESENTATIVE METALS

      The following metals include the TCLP analytes except mercury. Suggested low and
high concentrations are based on ICP  analysis and should be appropriate for relatively
uncontaminated solid matrices such as soil. Higher concentrations may be required for highly
contaminated samples.

 ELEMENT                    LOW fug/kg)             HIGH fug/kg)

Arsenic                         2500                     75,000
Barium                          100                      5,000
Cadmium                       200                     10,000
Chromium                      350                     17,500
Copper                          300                     15,000
Lead                           2000                    100,000
Silver                           350                     17,500
Zinc                            100                      5,000

Mercury is generally analyzed by cold vapor AA.

Mercury                        100                     5,000
                                       11

-------
April 23,1992

Dear Colleague:

       The Methods Team of the Office of Solid Waste is responsible for the promulgation of
rugged and  reliable  analytical  techniques in support of the Resource Conservation and
Recovery Act (RCRA) program. The methods published in Test Methods for Evaluating Solid
Waste, SW-846, are used to measure the concentration of specific pollutants or to establish
whether a waste stream demonstrates a hazardous characteristic (e.g. ignitability, corrosivity,
reactivity or toxicity).

       SW-846 currently provides reliable and sensitive laboratory methods for the analysis
of Appendix VIII analytes. However, some of these methods may be too costly or require too
much analysis time for some applications. The Methods Team also recognizes the savings that
could be achieved by  sending  only contaminated samples to analytical laboratories for
quantitative analysis. Therefore, the Methods Team has recognized the need for more rapid,
less expensive field screening procedures.

       A number of sources have developed reliable, reproducible and cost-effective field or
screening procedures with potential application for the RCRA program. This letter provides
developers with a description of the type of performance data that is required for an effective
initial evaluation of screening or field procedures. If a developer's data supports adoption of
a new  method, the Methods Team will work through the SW-846 Work Group process to
promulgate it.  This  letter does not supersede or replace the more rigorous requirements
described in Test Method Equivalency  Petitions. EPA/530-SW-87-008, OSWER Policy
Directive No. 9433.00-2 (2/87).  That  document provides the requirements for a method
equivalency petition which may be used to promulgate a method outside of the Work Group
process.

       While screening procedures need not be fully quantitative, they should  measure the
presence or absence of target analytes at or below regulatory action levels. Therefore, initial
demonstration of method performance involves measuring the percentage of false negatives
and false positives generated using the procedure for a single sample matrix. Data should be
submitted for split samples analyzed using the developer's technique and an approved SW-846
quantitative  method.  A candidate procedure should ideally produce no  false negatives.
Definition of a false negative is a negative response for a sample that contains the target
analyte(s) at or above the stated action level of the method.  A candidate procedure should
produce no more than 10% false positives. Definition of a false positive is a positive response
for a sample that contains the target analyte(s) below the stated action level of the method.
Between 20 and 50 samples spiked at one half the detection level should be tested to establish
the percentage of false positives.  Between 20 and 50 samples spiked at twice the detection level
should be tested to establish the percentage  of false negatives.  It is  recommended that a
sufficient volume of each spiked sample be prepared to  complete each test with one lot of
material. Sufficient randomly selected aliquots of each spiked matrix should be analyzed by

                                        12

-------
appropriate SW-846 methods to demonstrate sample homogeneity and to characterize the
sample in terms of target analytes and potential interferences.

      A separate study should also be conducted to  establish  the  effect of non-target
interferences. A screening procedure should produce no more than 10% false positives for a
set of 20 samples that contains a 100 fold excess of interferences. Positive interferences should
be selected that are chemically related to the target analytes and are environmentally relevant.
Negative interferences (i.e. masking agents) should also  be investigated whenever they are
suspected.

      Developers should also analyze three different  types of samples to provide  matrix-
specific performance data. These samples should either be characterized reference materials
or spiked matrices containing known amounts of target  analytes. In either case, bulk samples
should be carefully homogenized to reduce sub-sampling errors. The sample matrices should
be selected to represent what is regulated under RCRA (e.g. soil, oily waste or waste waters),
not to provide the best performance data. Blanks should be analyzed with each set of samples.

      Matrix-specific performance data, including detection limits and dynamic range, are
gathered by analyzing ten replicate aliquots of three different sample matrices spiked at two
concentrations. If spiked samples are used, suggested  spiking levels are the matrix-specific
detection limit and 50 times the detection limit. Positive  or negative results should be reported
for the low concentration samples. Results for high concentration samples should be reported
as either semi-quantitative results or as positive/negative with the dilution factor used for the
samples. As an alternative to establishing matrix-specific detection limits, specific  spiking
concentrations are provided for selected target analytes in the attachments to this letter.  The
low values are normal reporting limits for routine analyses and the high value is 50 times the
low concentrations.  The Methods Team recognizes that it may not be appropriate to spike all
of the target analytes listed within a chemical class.

      If the developer has field data, the Methods Team would welcome the opportunity to
compare the results obtained using  the screening procedure with sample concentrations
determined in a laboratory using SW-846 methods.

      To summarize, the Methods Team does not require an unreasonable body of data for
the initial evaluation of new techniques. Data will need to be submitted on the percentage of
false negatives, percentage of false positives, sensitivity  to method interferences, and  matrix-
specific performance data in order to complete the table below. In addition to these data, the
developer should also provide a description of the procedure and a copy of any instructions
provided with the test kits.
                                         13

-------
Type of sample
False positive
False negative
Interference
Matrix 1, low
Matrix 1, high
Matrix 2, low
Matrix 2, high
Matrix 3, low
Matrix 3, high
Number of
samples
20-50
20-50
20
10
10
10
10
10
10
number of samples
greater than the
detection limit









number of samples
less than the
detection limit









semi-quantit-ative
results/
dilution factor









      It is our belief that completion of this table represents only a small fraction of a
developer's effort in developing a new method.  If your technique will improve the quality of
EPA monitoring programs, submitting these data should expedite the SW-846 approval
process.

      I look forward to working with you on this important activity.

                                      Sincerely,
                                      Barry Lesnik
                                      Organic Methods Program Manager
                                      USEPA Office of Solid Waste
                                      Methods Team (5307W)

attachments
                                        14

-------
              REPRESENTATIVE ORGANOCHLORINE PESTICIDES

      The following chlorinated pesticides from the Best Demonstrated Available Technology
(BDAT) list are representative of analytes for Method 8081. All should be sufficiently resolved
to ensure good  quantitation  using  two columns  such as the DB-608 or DB-1701 (or
equivalents).  Suggested low and high concentrations should be appropriate for relatively
uncontaminated solid matrices such as soil. Higher concentrations may be required for highly
contaminated samples.

COMPOUND                         LOW fug/kg)            HIGH fug/kg)

Aldrin                                5                       250
P-BHC                                5                       250
5-BHC                                5                       250
y-BHC (Lindane)                      5                       250
a-Chlordane                           5                       250
y-Chlordane                           5                       250
4,4'-DDD                              10                      500
4,4'-DDE                              5                       250
4,4'-DDT                              5                       250
Dieldrin                               5                       250
Endosulfan I                           5                       250
Endosulfan II                         5                       250
Endrin                                10                      500
Endrin aldehyde                       5                       250
Heptachlor                            5                       250
Heptachlor epoxide                     5                       250
                                        15

-------
                REPRESENTATIVE SEMIVOLATILE COMPOUNDS
      The following compounds are representative of analytes for Method 8270. Although
many of these compounds are considered difficult, all can be extracted from waste matrices
using conventional techniques. Suggested low and high concentrations should be appropriate
for relatively uncontaminated solid matrices  such as soil. Higher  concentrations may be
required  for highly  contaminated samples. Phthalate esters are not spiked but should be
reported  as a measure of contamination.

 COMPOUND                         LOW fug/kg)             HIGH fug/kg)
Phenol                                250                      12,500
o-Cresol                               250                      12,500
2-Methyl phenol                       250                      12,500
2,4,6-Trichlorophenol                   250                      12,500
Pentachlorophenol                     250                      12,500
1,2-Dichlorobenzene                   250                      12,500
Naphthalene                           250                      12,500
2-Chloronaphthalene                   250                      12,500
Anthracene                            250                      12,500
Chrysene                             250                      12,500
Benzo(a)anthracene                    250                      12,500
Benzo(a)pyrene                        250                      12,500
Fluoranthene                          250                      12,500
Indeno(l,2,3-cd)pyrene                 250                      12,500
Benzo(g,h,i)perylene                   250                      12,500
o-Toluidine                            250                      12,500
p-Nitrotoluene                         250                      12,500
2,6-Dinitrotoluene                     250                      12,500
2-Nitroaniline                          250                      12,500
Di-n-propylnitrosamine                 250                      12,500
4-Bromophenyl phenyl ether            250                      12,500
3,3'-Dichlorobenzidine                 250                      12,500

In addition, surrogates should be added such that 50 //g or 100 //g would be present in final
extracts assuming 100% recovery.

Nitrobenzene-d5                  50
2-Fluorobiphenyl                 50
p-Terphenyl-d14                  50
Phenol-d6                       100
2-Fluorophenol                  100
2,4,6-Tribromophenol            100
                                        16

-------
                   REPRESENTATIVE VOLATILE COMPOUNDS

      The following compounds are representative of analytes for Method 8260; many are
TCLP analytes.  All can be purged from waste matrices using Methods 5030 or 5035.
Suggested low and high concentrations should be appropriate for relatively uncontaminated
solid matrices such as soil. Higher concentrations may be required for highly contaminated
samples.

 COMPOUND                         LOW fug/kg)             HIGH fug/kg)

Vinyl chloride                         5                        250
Dibromochloromethane                5                        250
1,1-dichloroethane                     5                        250
Chloroform                            5                        250
Carbon tetrachloride                   5                        250
Trichloroethylene                      5                        250
1,1,1-Trichloroethane                   5                        250
Benzene                               5                        250
Toluene                               5                        250
Ethylbenzene                          5                        250
Chlorobenzene                         5                        250
Nitrobenzene                          5                        250
Methyl ethyl ketone                    5                        250
Carbon disulfide                       5                        250

      The following compounds are representative of non-purgeable volatiles which currently
require azeotropic distillation. Suggested low and high concentrations should be appropriate
for relatively uncontaminated solid matrices such as soil.  Higher concentrations may be
required for highly contaminated samples.

 COMPOUND                         LOW fug/kg)             HIGH fug/kg)

1,4-Dioxane                            10                       500
n-Butanol                             10                       500
iso-butanol                            10                       500
Ethyl acetate                          10                       500
Pyridine                               10                       500
                                        17

-------
                          REPRESENTATIVE METALS

      The following metals include the TCLP analytes except mercury. Suggested low and
high concentrations are based on ICP  analysis and should be appropriate for relatively
uncontaminated solid matrices such as soil. Higher concentrations may be required for highly
contaminated samples.

 ELEMENT                    LOW fug/kg)             HIGH fug/kg)

Arsenic                         2500                     75,000
Barium                          100                      5,000
Cadmium                       200                     10,000
Chromium                      350                     17,500
Copper                          300                     15,000
Lead                           2000                    100,000
Silver                           350                     17,500
Zinc                            100                      5,000

Mercury is generally analyzed by cold vapor AA.

Mercury                        100                      5,000
                                       18

-------
 DEVELOPMENT AND
  VALIDATION OF
  SW-846 METHODS
     PHASE 2:
FORMAL VALIDATION

-------
            DEVELOPMENT AND VALIDATION OF SW-846 METHODS
                         PHASE 2: FORMAL VALIDATION

      If a methods developer successfully demonstrates  that the method appears to  be
applicable for its intended application(s) through the "proof of concept" stage, as described
in the previous section of this document, OSW will then consider incorporating the proposed
method into SW-846 after it has completed the formal validation process.  The document
included in this section describes OSW's formal validation process and documentation
requirements for new methods submissions. Multilaboratory validation data is necessary for
a method to be considered for inclusion in SW-846.

      The document included in this section delineates OSW's basic approach to developing
and validating analytical methods for the RCRA Program. It is based on the performance-
based approach to RCRA regulatory policy, i.e., the generator must demonstrate the ability
to measure the analytes of concern in  the matrices of concern at the regulatory limits.  It
involves the same elements for method development that RCRA requires for a demonstration
of analyst and method proficiency in the standard Quality Assurance Project Plans (QAPjP)
described in Chapter One and the technique-specific methods, e.g., Method 8000 in SW-846.

      The RCRA method development approach utilizes three basic principles:

      1)    Identify the scope and application of the proposed method, (What is this
            method supposed to accomplish?)

      2)    Develop a procedure that will generate data that are consistent with the
            intended scope and application of the method, and

      3)    Establish appropriate quality control procedures which will  ensure that when
            the proposed procedure is followed, the method will generate the appropriate
            data from Step 2 that will meet the criteria established in Step 1.

      A developer  must also meet two  other specific criteria  before a method will  be
considered for inclusion in SW-846 are: 1) Is there either an existing  or anticipated RCRA
regulatory need for this method, and 2) Is it significantly different in principle or approach
from existing SW-846 methods?

      OSW has identified eleven key elements essential to a sound method  development and
validation effort. These are listed in Table 1 on the next page.

      These principles should also be followed when an analyst uses the built-in flexibility of
SW-846 to  modify  methods  for particular applications.   Qualified analysts should  be
considered as "in-house" methods developers (Elements 1 to 9) when measurements are to be
made from unusual matrices or below the quantitation limits provided with conventional SW-
846 or other appropriate methods.

-------
       Table 1: Key Elements for Regulatory Methods Development

Element  1:  Identification of Scope and Application and Regulatory Need

Element  2:  QA/QC Requirements

Element  3:  Analytical Approach

Element  4:  Method/Instrument Sensitivity

Element  5:  Method Optimization and Ruggedness Testing

Element  6:  Accuracy, Precision and Repeatability (Clean Matrix)

Element  7:  Effect of Interferences

Element  8:  Matrix Suitability

Element  9:  Quantitation and Detection Limits

Element 10:  Laboratory  Reproducibility   (Multiple  Operators  and Multiple
            Laboratories)

Element 11:  Document Submission and Workgroup Evaluation
                                 21

-------
    METHODS DEVELOPMENT AND VALIDATION FOR THE RCRA PROGRAM

Introduction

      There  seems to be an impression among methods developers and the regulated
community that there is some esoteric or mystical process that must be followed in order to get
an analytical method "approved" by regulatory agencies like the USEPA. In this document,
OSW would like to dispel these misconceptions, identify some basic principles, and present a
logical approach to methods development that is currently followed by the Office of Solid
Waste (OSW) in developing methods for SW-846. This approach is based on sound scientific
principles, and methods developed according to this process should be acceptable for use in
other Agency programs as well as OSW.

Basic Principles

      The basic principles involved in analytical methods development are very simple
adaptations of the scientific method and can be summarized in the following three steps:

      1)     Identify the  scope  and application of the  proposed method, (What is this
             method supposed to accomplish?)

      2)     Develop a procedure  that will  generate data that are consistent with the
             intended scope and application of the method, and

      3)     Establish appropriate quality control procedures which will ensure that when
             the proposed procedure is followed, the method will  generate the appropriate
             data from Step 2 that will meet the criteria established in Step 1.

      Two other specific criteria that a developer must also meet before a  method will be
considered for inclusion in SW-846 as a separate method are: 1) Is there either an existing or
anticipated RCRA regulatory need for this method, and 2) Is it  significantly different in
principle or approach from existing SW-846 methods? The rest of this document will provide
more detail, including eleven key elements for methods development, and two examples of how
this approach has been used successfully in the development of methods for SW-846.

The Nature of Regulatory Analysis

      Regulatory analyses cover a wide variety of applications from regulatory compliance
to informational data gathering. Some analyses are used to satisfy legal requirements, while
others are used for monitoring of internal waste streams within a generator's facility.

      Analyses used to determine the extent of contamination of a grossly contaminated site
in the high ppm to low % range do not need to be performed with the same degree of precision
and accuracy as analyses performed to demonstrate compliance with corrective action cleanup

                                         22

-------
levels in the low ppm to ppb range. Other factors to be considered in performing regulatory
analyses include intended use of the data generated (i.e., project data quality objectives),
method ruggedness and  sensitivity,  analyte/matrix interactions, laboratory performance,
availability of equipment, and cost. All of these factors and more are taken into consideration
when developing methods for regulatory purposes.

Key Elements for Regulatory Methods Development

       Methods developers should address the following eleven elements, which are listed in
Table 1, when developing methods for OSW and other regulatory programs:

 L.     Identification of Scope and Application and Regulatory Need

       The key factor that a developer must establish before proceeding with a method
development project is a clearly defined scope and application for the proposed method.
Factors to be considered should include  type of method, (i.e., screening or assay), applicable
target analytes, appropriate matrices, sensitivity, bias and precision, availability of equipment,
and cost. It is advisable to limit the scope of most potential new methods, because a method
that works well for a few specific applications is usually much more useful (and marketable)
than one which is marginal for a large  number of applications.  Also, remember that it is
usually much easier to develop and market a method that is designed around commercially
available equipment. Cost is also a significant factor in determining whether a method has
potential utility and marketability.  Very few laboratories are prepared to buy expensive
equipment today when comparable methods will do  an adequate job at a much more
affordable cost.

       When establishing the scope and application for a potential new method, it is essential
that the method developer identify that there is  a regulatory need for the method. This can
be a current or anticipated program office regulatory requirement determined by the methods
staff, a Regional need, or a need for a method improvement identified by calls to Agency
information services such as the MICE line.  A method may be scientifically elegant, but it has
very little value if there is no application for its use in the regulatory program for which it is
intended.  For example,  tissue samples and nutrients, e.g., ammonia and nitrate, are not
usually of concern to the RCRA program. Therefore, methods addressing these matrices and
analytes would be of low priority to  OSW, although they may be of great interest to other
Agency programs.

 2.     Quality Control Requirements

       When developing a method, the developer needs to identify the appropriate quality
control procedures  that must be performed to unequivocally demonstrate that the data
generated by the  method  will  meet the  objectives defined in the scope  and intended
application(s). General QC procedures for RCRA analyses can be found in Chapter One of
SW-846. Technique-specific QC procedures are included in the overview methods in SW-846,

                                         23

-------
e.g., Method 8000 (Chromatography), Method 3500 (Extraction), Method 3600 (Sample
Preparation for Volatile Organics), Method 4000 (Immunoassay) and Method 7000 (Atomic
Absorption). Method-specific QC procedures are included in the Quality Control section of
the individual methods. When an apparent contradiction between QC criteria occurs in SW-
846, the order of precedence is as follows: method-specific QC criteria have precedence over
technique-specific QC criteria which have precedence over Chapter One QC criteria.

      Examples of QC factors include appropriate calibration or tuning criteria, the need for
replicate analyses, appropriate surrogates, blanks and  spikes.  QC criteria specific to the
particular method should be well-documented and included in the QC section of the method
as well  as the method development  project report.  General and technique-specific QC
requirements should be included in the Quality Assurance Project Plan (QAPjP) during the
planning stage and in the project report (Section 11).

 3.    Analytical Approach

      In developing an analytical approach, the developer should keep in mind that the
ultimate goal of the project is to develop a method that will be published for general use by the
analytical community.  Therefore, it is essential that  any analytical instrumentation or
equipment used in the development of the method needs to be commercially available to
potential users at the time of the publication of the method.  OSW encourages the use of either
conventional or innovative technology, provided that it is demonstrated to be appropriate for
the intended method application and provides data of sufficient quality to satisfy the criteria
delineated in the scope of the method.  OSW has been leading the effort to introduce new
innovative  analytical  technologies to EPA's  regulatory  programs.   Examples of new
technologies  first  introduced  in SW-846 include  microwave digestion,  potentiometric
voltammetry, HPLC/MS, Immunoassay, Supercritical Fluid Extraction (SFE), and Accelerated
Solvent Extraction (ASE). Those who criticize regulatory methods because they do not include
innovative technologies are not aware of the level of review required for method promulgation.

      In order to be considered for inclusion is SW-846, a method must be practical, i.e., has
the potential for general use in the environmental analytical community, address a RCRA
regulatory need, and  be significantly different from existing SW-846 methods.  Neutron
Activation is a technique which has been used for analysis of metals for RCRA compliance.
However, it is not an appropriate candidate for inclusion in SW-846 as a general-use method,
since relatively few analytical laboratories have ready access to a nuclear reactor.

 4.    Method/Instrument Sensitivity

      The method sensitivity requirements for a proposed new method are influenced by
several factors. These include the instrument detection limits, method quantitation limits, and
the regulatory requirements for the proposed  applications. RCRA regulations basically
require that an analyst demonstrate the ability to measure the analytes of regulatory concern
in the matrices of concern at the regulatory levels. Therefore, a method must exhibit analytical

                                        24

-------
sensitivity appropriate for its intended application, as delineated in the scope of the method,
before it will be considered for inclusion in SW-846. Many applications in the RCRA and
other EPA programs do not require the use of methods at their extreme limits of instrument
or method sensitivity.  Pertinent performance information submitted in the methods package
should include the instrument or method detection and quantitation limits, i.e., the minimum
mass of analyte which can be quantitated (or detected, in the case of screening methods), the
instrument or method calibration range for all target analytes, and information as to whether
the calibrations are linear or non-linear (per the criteria in Method 8000). At this stage in the
methods development process, the analyst should demonstrate the appropriate  analytical
parameters and procedure on clean standards of known concentration.

 5.     Method Optimization and Ruggedness Testing

       After determining that the chosen analytical approach should work for its intended
application with appropriate sensitivity, the method developer should begin to optimize the
method and determine whether it possesses sufficient ruggedness to be considered for inclusion
in SW-846. This is also accomplished using known standards.

       The initial parameters should be chosen according to the analyst's best judgment.
These are varied systematically (usually using  Youden pairs as described in J. K. Taylor,
Quality Assurance  in Analytical  Measurements)  to  obtain the  greatest response, least
interference, greatest  repeatability, etc.  Developers must determine those variables which
should not be changed without adversely affecting method performance.  Potential operator-
sensitive steps, e.g., color development time in colorimetric methods or other timed reactions,
also need to be identified at this stage.

 6.     Accuracy (Bias), Precision, Repeatability (or Long-term Precision) in a Clean Matrix

       Accuracy, or in most cases method bias,  is defined as  nearness to the true value.
Precision is defined as the dispersion of results around the mean value. Repeatability (or long-
term precision) is defined as the ability to reproduce a measurement from one week to the next.

       Bias is measured by determination  of % recovery of target analytes spiked into the
matrix of concern.   An  acceptable spike recovery range for most method development
applications is from 80%  to 120%. Precision is measured as relative %  difference of target
analyte concentration(s) between duplicates or duplicate spikes, and should usually be <20%.
Repeatability is measured  as long-term, e.g.,  weekly, precision,  when the instrument is
calibrated using comparable standards, and on a different day should not vary by more than
15%.

       These are key method performance factors which determine how a method can be used
in real world situations. The initial determination of bias, precision and repeatability should
be made in a spiked clean matrix which is similar to a real environmental matrix, but free from
interferences, e.g., reagent water, sand, soil (for inorganic methods), vermiculite or ash. These

                                         25

-------
values should be obtained using multiple replicates at both high and low spike concentrations.
Guidance on bias and precision determinations and preliminary method evaluation for new
sample preparation and screening methods is available from the Office of Solid Waste.

 7.    Effect of Interferences

      The determination of method interferences, both positive and negative is a key factor
in method development. It is a critical element in methods development for the developer to
determine  the  effects of potential analytical interferences and to develop techniques to
minimize or eliminate these interferences. In chromatographic methods, interferences include
coeluting peaks and/or analyte degradation due to interaction with either the injector port,
transfer line or column.  In spectroscopic methods, interferences can result from overlapping
spectral lines  causing either positive or negative signal  enhancement.  In immunoassay
methods, interferences include cross-reacting compounds.

      Method interferences should be determined in a spiked clean matrix. Developers should
determine the effects of interferences in a potential new method between target analytes and
other compounds reasonably expected to be present in waste matrices.

      False negative rates, i.e., the percentage that a method generates a negative result when
the sample contains the target analytes at or above the action level and false positive rates, i.e.,
the percentage that a method generates a positive result when the sample contains the target
analytes below the action level, are critical factors which will determine the utility of a
potential method for its  intended application.

      Documentation of interferences should include any coelution of or with target analytes,
any  enhancement or suppression  of target  analyte  signals  caused by interferences, any
necessary or optional cleanup procedures to minimize the effect of interferences, and any
matrix-specific difficulties.

 8.    Matrix Suitability

      The previous elements of the methods development process involved the use of either
known standards or target analytes spiked into clean matrices, designed to indicate potential
method performance in  real RCRA matrices.  Once the potential new method has passed all
of the preliminary tests, it is now ready for the most important demonstration in the entire
methods development process, i.e., how it will perform in the real world matrices for which it
is intended to be used.

      The method should be suitable for a variety of matrix types. Therefore, the developer
should choose appropriate RCRA matrices for the demonstration of method performance.  By
matrix types, OSW refers to different matrices within a particular medium, e.g. water, soil and
ash.  Appropriate RCRA water matrices include groundwater, TCLP leachate and wastewater,
while appropriate RCRA soil matrices include sand, loam and clay. Appropriate ash matrices

                                         26

-------
include bottom ash, fly ash and/or combined ash. The method should perform adequately in
a variety of spiked matrices and then in a variety of well-characterized natural samples or
standard reference materials (SRMs) when SRMs are available. Performance data including
matrix, precision, bias, quantitation limits (see next section), and any other pertinent data
should be documented in appropriate tables. A summary of the single-laboratory performance
data should be included in tabular format in the method while the detailed performance data,
including QC, should be included in the supporting document (Section 11).

 9.     Method Detection and Ouantitation Limits

       In a new method submission, OSW is most concerned about the performance of the
method in the RCRA matrices of concern.  The developer should generate estimated method
quantitation (EQL)  and method detection limits (MDL) for the analytes of concern in the
matrices  of concern following the guidelines established in Chapter One of SW-846. The
practice of generating MDLs based on reagent water is not usually a very useful parameter for
most RCRA methods.

       Method detection and quantitation limits for a determinative method are usually based
on a specific sample size and a specific sample preparation scheme. The limits determined in
clean matrices indicate the limits of the acceptable performance for the method. Matrix effects
may affect the achievable quantitation limits on real world samples. However, the method
quantitation limits for  the target analytes in  the target matrices must meet the analytical
requirements of the intended application, as defined in the scope of the method, before it can
be considered for inclusion in SW-846.   Quantitation limits  for the target analytes in
representative matrices should be included in summary tables in  the methods, while the
rationale for and details of the MDL and EQL concentrations should be  included in the
supporting document (Section 11).

10.    Laboratory Reproducibility (Multiple Operators and Multiple Laboratories)

       The final stage in the method development process, prior to the  submission of the
method  for Agency review, is  the determination  of laboratory reproducibility.  By
reproducibility, OSW means that multiple operators and multiple laboratories should be able
to obtain comparable performance data on split samples using the method.  Since all of the
previous  elements involved single  operators or single laboratories, it is necessary  to
demonstrate that satisfactory method performance is not limited to the individual operator or
laboratory that developed the method.

       The  minimum  number of  laboratories  that are  needed  to  participate in  a
multilaboratory method validation is three, with preferably more. In previous years, when the
Agency budget permitted, multilaboratory validations of new methods were funded by the
Agency.  Large numbers of laboratories were paid to participate in these studies with EPA
doing the "data-crunching". Agency funding can no longer support these types of studies, so
developers of new methods today need to do a limited  multilaboratory evaluation and provide

                                        27

-------
the individual laboratory and summary performance  data  in the method submission.
Developers are encouraged to consult with the appropriate regulatory agency when planning
a multilaboratory study.

      In order to  minimize the number of variables involved in method validation, the
developer needs to follow a few simple guidelines to demonstrate appropriate multilaboratory
method  performance.  When validating a  sample preparation method, the participating
laboratories should only perform the sample preparation procedure. The collected samples
should then be sent to one laboratory for analysis. The analysis should be  done by a single
operator on a single instrument in a single batch to minimize analytical variability inherent
to the determinative method. Conversely, if a determinative method is  to be validated, the
developer should have a single operator perform all of the sample preparation operations in
order to minimize operator and laboratory variability inherent to the sample preparative
procedures. The sample extracts should then be split and sent to the laboratories participating
in the validation study for the analytical determination.

11.    Document Submission and Workgroup Evaluation

      When  the method  project is completed, the developer must assemble a package of
documents describing the proj ect, and submit it to the Agency for review and evaluation. This
documentation package should include 1) draft copies, both hard and electronic, of the method
in an appropriate Agency  format; 2) a supporting document describing the rationale behind
the methods development effort and how the key elements of the methods development project
as described in this document were addressed; 3) a data package containing both the raw and
summarized single laboratory and multilaboratory data; 4) any specific equipment diagrams
and chromatograms, spectra, etc. pertinent to the demonstration of appropriate performance
for the intended application of the method; 5) copies of any references listed in the method;
and 6) any method-specific quality control criteria.

      The OSW Methods Team reviews the methods submission package for completeness
and quality,  and then  decides whether the method is  ready to  be sent to the  SW-846
Workgroup for review  or back to the developer  for additional work. OSW has several
standing SW-846 Methods Workgroups which meet formally each July to review the methods
packages submitted by developers for  potential inclusion  in SW-846. Workgroup members
are Agency scientists from the EPA Program Offices,  Regional  Laboratories, Office of
Research and Development (ORD), and the National Enforcement Investigations Center
(NEIC)  who  evaluate the procedures and  performance data submitted  by the methods
developers. Workgroup members provide the benefit of their own experience in performing
and evaluating analyses.  Workgroup comments address both the written  method and the
completeness of the performance data, other method documentation, and interpretation of the
data.  Methods which the Workgroups accept for  inclusion in  SW-846 are edited based on
Workgroup comments.  After editing, the OSW-Methods Team distributes them  as draft
methods until the SW-846 Update package of which they  are a part is ready to be submitted
for Agency approval  through the official regulatory "notice and comment" process. The

                                        28

-------
supporting documentation for each method is then put into the RCRA Docket for public
review immediately before the initial proposal of the new SW-846 Update package.

Conclusion

      OSW believes  that the information provided here clarifies the  RCRA method
development process.   Qualified analysts  should be  considered as "in-house" methods
developers (Elements 1 to 9) when measurements are to be made from unusual matrices or
below the quantitation limits provided with conventional  SW-846  or  other appropriate
methods.  The need for such a demonstration of analyst/laboratory proficiency has been
implicit in SW-846 Chapter One and Method 8000. These implicit requirements have been
clarified and made explicit in Method 8000B, which is included in Update 3.

Practical Examples of Methods Developed Using the RCRA Validation Process

      This section of  the document provides two examples  of methods  developed for and
included  in Update 3 of SW-846.  Example Number One is of a sample preparation method
developed for use with  existing SW-846 determinative methods. Example Number Two is of
a screening method for determining the range of concentrations of PAHs in soils.

Example 1:  Method 3545 - Accelerated Solvent Extraction  (ASE)

      The Accelerated Solvent Extraction Method (Method 3545) was developed by Dionex
as a rigorous, rapid sample preparation method for  extractable organic analytes in solid
matrices using small quantities of solvent. The following paragraphs provide a brief overview
of how Method 3545 was developed using the analytical approach discussed in this document:

       1)   ASE was developed as a general-purpose, rigorous extraction procedure for
            RCRA extractable analytes amenable to the Soxhlet technique, either manual
            or automated,  and with comparable performance.  It also uses much less
            extraction solvent than the existing general-purpose techniques, thus helping to
            promote the Agency's policy of pollution prevention in analytical methods.

       2)   No method-specific QC procedures are necessary.

      3)   The analytical approach uses conventional solvents as the extraction fluid rather
            than supercritical CO2, while utilizing the basic  operations of supercritical fluid
            extraction (SFE), e.g., elevated temperature, elevated pressure, and minimum
            void volume. Dionex has demonstrated that these conditions provide a rigorous
            extraction of the target analytes from a solid matrix in minutes instead of hours.

       4)   The method sensitivity using standard  determinative methods, i.e, Methods
            8270, 8081, 8082, 8141,  and 8151, is comparable to Soxhlet using the same
            sample size.

                                        29

-------
       5)     The method was  optimized  using about  a 10-minute extraction with the
             appropriate extraction solvents for the target analytes, e.g., methylene chloride,
             hexane:acetone, etc., at a temperature of about 100C and a pressure of about
             2000 psi (a relatively low pressure for SFE). Sample size can be varied without
             changing the extraction conditions by varying the size of the extraction vessels
             used.

       6)     Recoveries (bias) in a sandy soil, a loam, and a clay were comparable to Soxhlet
             extraction, while precision (%RSD) was a little better than standard Soxhlet
             and about the same as Automated Soxhlet.  Repeatability was not a problem.

       7)     ASE did not appear to  generate any additional interferences other than those
             commonly encountered in Soxhlet procedures.

       8)     Method 3545 was validated in a variety of soil matrices ranging from sand to
             clay and demonstrated  performance comparable to that of automated Soxhlet
             extraction. Due to time and cost factors, the method was not evaluated in other
             RCRA matrices. However, OSW believes that it should be appropriate for all
             RCRA matrices for which Soxhlet extraction is currently used, based on the
             performance data submitted with the method.

       9)     Quantitation and detection limits based on Method 3545 recovery data from
             soils for the standard determinative methods were comparable to those obtained
             using automated Soxhlet extraction.

       10)    The method was  performed in  three  laboratories, all of which  obtained
             acceptable results.

       11)    Method 3545 was reviewed by the SW-846 Organic Methods Workgroup in
             July, 1994, and was accepted for inclusion in Update 3 of SW-846. Dionex
             submitted a second documentation package containing  performance data for
             additional analytes in November, 1994. Both reports are included in the RCRA
             Docket supporting Update 3.
Example 2:   Method 4035 - Screening Method for PAHs in Soil by Immunoassay

      The PAH immunoassay method was developed by EnSys as a screening method for
PAHs in soils at cleanup levels. It was the first method included in RCRA's second group of
immunoassay methods accepted for  inclusion  in Update 3 of SW-846.  The following
paragraphs provide a brief overview of how Method 4035 was developed using the analytical
approach discussed in this document:
                                        30

-------
1)    Method 4035 was developed as a screening method for PAHs containing 3- and
      4-ringed PAHs at the nominal RCRA/CERCLA cleanup action level of 1 ppm.
      It was also one of a series of methods which addressed the Agency's need for
      low-cost, rapid, effective screening methods which could be used either on-site
      or in a fixed laboratory. The target false negative rate for screening methods is
      0%, while the target false positive rate is 10%.

2)    Standard QC requirements apply to immunoassay testing. However, there are
      some specific QC criteria for immunoassay methods which must be followed.
      These include 1) do not use test kits past their expiration date; 2) do not  use
      tubes or reagents designated for use with other kits; and 3) use the test kits
      within the specified storage temperature and operating temperature limits.

3)    The analytical approach used was an inverse colorimetric method utilizing a
      competitive antibody technique sensitive to the target PAHs, i.e., color was
      discharged when the target PAHs were present at or above the action level.

4)    The sensitivity of the test is influenced by the binding of the target analyte to the
      antibodies used in the kit. The commercial PAH kit used for evaluation of this
      method is most sensitive to the three- (i.e., phenanthrene, anthracene, fluorene)
      and four- (i.e. benzo(a)anthracene, chrysene, fluoranthene, pyrene) ring PAH
      compounds listed in Method 8310, and also recognizes most of the five- and six-
      ring compounds listed. The method can be used for screening the target PAHs
      at various predetermined action levels down to 1 ppm.

5)    Method 4035 (EnSys) was optimized for PAHs containing 3- and 4-ringed PAHs
      in a variety of soil matrices.

6)    Screening data correlated >95%  with the reference  method used (Method
      3540/8270) for the target analytes.

7)    Interferences for immunoassay methods are referred to as cross-reactivity. The
      target compound for the  EnSys PAH kit with a cross-reactivity of 1 was
      phenanthrene. The other 3- and 4-ringed compounds had similar responses.
      All  of the 16 RCRA target compounds had a cross-reactivity within one order
      of  magnitude   of   phenanthrene,  except   for  naphthalene   (200),
      dibenzo(a,h)anthracene and benzo(g,h,i)perylene (both  >200).  The  kit was
      optimized to respond  to three and four ring PAHs. The sensitivity of the test to
      individual PAHs is highly variable. Naphthalene, dibenzo(a,h)anthracene, and
      benzo(g,h,i)perylene have 0.5 percent or less than the reactivity of phenanthrene
      with the enzyme conjugate. The alkyl-substituted PAHs, chlorinated aromatic
      compounds, and other aromatic hydrocarbons, such as dibenzofuran, have been
      demonstrated to be cross-reactive with the immobilized anti-PAH antibody.
      The presence of these compounds  in  the sample may contribute to false

                                 31

-------
      positives.

8)    The EnSys PAH kit was designed for use in soil matrices. It was demonstrated
      to be applicable to a cross-section of soil types from sand to loam to clay.

9)    Method 4035 is designed to act as a screening method at a predetermined action
      level (usually 1 ppm). Using the test kit from which this method was developed,
      >95% of samples confirmed to have concentrations of PAHs below detection
      limits will produce a negative result in the 1 ppm test configuration.

10)   Multiple field trials involving split samples were conducted at a power plant site
      and on  a variety of well-characterized samples from Region 10  ranging in
      concentration from <0.1 ppm to >200 ppm. Several operators and laboratories
      participated in the studies. Actual false negative rates were <5%, while false
      positive rates ranged between  10 and 15%.

11)   Method 4035 was reviewed by the SW-846 Organic Methods Workgroup in
      July, 1993, and was accepted for inclusion in Update 3 of SW-846. The method
      has been available in draft form from OSW since early in 1994. The original
      data submission package and  the Region 10 study results are included in the
      RCRA Docket supporting Update 3.
                                  32

-------