hington, DC 20460
EPA 821-B-93-OO1
. June 1993
illance Mbhiforini
COMPLIANCE?
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Recycled/Recyclable
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Disclaimer
This report has been reviewed by the Analytical Methods Staff
within the Engineering and Analysis Division of the EPA Office of Water.
Mention of trade names or commercial products does not constitute endorsement
or recommendation for use.
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Foreword
This guidance document was prepared in response to questions directed to the Environmental
Protection Agency (EPA) Headquarters by EPA Regions and various state agencies about monitoring
compliance with the Organic Chemicals, Plastics, and Synthetic Fibers (OCPSF) Effluent Guideline
Limitations promulgated by EPA in 1987. The Engineering and Analysis Division (BAD) in EPA's
Office of Science and Technology within the Office of Water is responsible for promulgation of
regulations controlling the discharge of pollutants into surface waters. BAD has developed analytical
methods and collected and validated analytical data as part of the rulemaking process. To support
compliance monitoring, BAD provides assistance to the EPA Regions and the States in evaluating
claims of matrix interference problems associated with OCPSF and other proposed and promulgated
regulations.
Recognizing that the guidance necessary to deal with these issues goes beyond the OCPSF
Rule and beyond those Regions and States that have requested assistance, BAD has compiled this
guidance under one cover for use by permit writers, permittees, laboratories, and other interested
parties. This document is organized into six chapters:
• Data required to document matrix-related problems
• Guidance to analysts attempting to identify pollutants in OCPSF wastewaters
• Cost estimates for resolving matrix-related problems
• Guidance for review of data from EPA 600- and 1600-series methods for organic
compounds
• Case histories of claims of matrix interferences
• Contracting for analytical services
This document addresses only those issues related to the analysis of organic compounds regulated
under the OCPSF rule, but much of the approach can be applied to the analysis of other organics as
well as to metals.
This document presumes knowledge of, or access to, the relevant analytical methods under
discussion. The authors have found it necessary to sacrifice some level of detail in order to address
as broad a range of situations as possible. Some analytical problems and some samples are not
addressed in these pages. However, the approaches used to demonstrate the magnitude of problems
with sample matrices can be applied to issues not specifically addressed here.
EPA's Engineering and Analysis Division is solely responsible for the content of this docu-
ment. The document was prepared, in part, by DynCorp Viar Inc., under U.S. EPA Contract 68-DO-
0083. Comments, suggestions, and requests for additional copies should be directed to:
William A. Telliard, Chief
Analytical Methods Staff
Engineering and Analysis Division
Office of Science and Technology
U.S. Environmental Protection Agency
401MSt.,SW
Washington, DC 20460
in
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Table of Contents
Chapter 1
Checklist of Laboratory Data Required to Support a Claim
that the Permittee was Unable to Measure Pollutants
Due to Matrix Problems
Chapter 2
Guidance for Analysts Attempting to Identify and Quantify Pollutants
in Wastewaters Discharged from Plants Manufacturing
Organic Chemicals, Plastics, and Synthetic Fibers
Chapter 3
Cost Estimates for Resolving Matrix Interferences
Chapter 4
Guidance for Reviewing Data
from the Analysis of Organic Compounds
Using EPA 600- and 1600-Series Methods
19
21
Chapter 5
Case Histories of Claims of Matrix Interferences
Submitted Under the OCPSF Rule
Chapter 6
Guidance on Contracting for Analytical Services
33
39
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Chapter 1
Checklist of Laboratory Data Required
to Support a Claim that the Permittee was Unable
to Measure Pollutants Due to Matrix Problems
The Federal Water Pollution Control Act (FWPCA) Amendments of 1972, later amended as
the Clean Water Act (CWA), require that all facilities that discharge wastewaters to the surface waters
of the United States maintain a permit for such discharges under the National Pollutant Discharge
Elimination System (NPDES). In addition, all such permitted dischargers (permittees) must monitor
their effluent for compliance with any and all relevant federal and state discharge limitations.
CWA Section 304(h) requires EPA to promulgate test procedures appropriate for the measure-
ment of regulated pollutants, commonly known as "the 304(h) methods." These methods are then
published at 40 CFR Part 136. Test procedures may also be promulgated by EPA under the authority
of other CWA sections, and these procedures are typically incorporated in revisions of 40 CFR Part
136. For some inorganic analytes and some organic pesticides, the test procedures promulgated under
Section 304(h) include methods sponsored by organizations other than EPA, such as the American
Society for Testing and Materials (ASTM) and the U.S. Geological Survey (USGS).
The permittee must use the 304(h) methods or methods promulgated in other regulations to
demonstrate compliance with NPDES permit limitations. The 304(h) methods for non-pesticide
organic compounds promulgated in 40 CFR Part 136 (49 FR 43234; October 26, 1984, and later
corrections) are commonly referred to as the "600-series" and "1600-series" methods. This chapter
"addresses issues related to the analysis of organic compounds, but much of the general approach can
be applied to the analysis of metals and other inorganics as well.
Table 1, at the end of this chapter, lists all of the 600- and 1600-series methods, indicating
each method number, the general class of analytes to which each is applicable, the instrumentation
required, and the regulatory status of each method (promulgated, proposed, or draft). These methods
were designed to be applicable to a wide range of industrial effluents and were used to generate the
data necessary for the development of each of the effluent guidelines promulgated by EPA. Despite
this wide applicability, EPA recognizes that some sample matrices may fail to yield useful results
when these analytical methods are employed. Therefore, EPA is prepared to consider claims that the
effluent is compliant in those instances in which the effects of the sample matrix make measurements
difficult or impossible. All such claims must be supported by specific analytical data; stating that "the
sample could not be analyzed" is not acceptable documentation.
This chapter outlines the analytical data and other information required by EPA to evaluate a
permittee's claim of compliance when complex matrices preclude measurement of the pollutants listed
in the permit. The data required are identical to those gathered by EPA in developing the regulation.
Since different instrumentation provide different data (e.g., GC/MS procedures produce plots
of mass intensities while GC procedures do not), the specific form of the data will differ according to
the method. The following numbered items describe the data required to support a claim of compli-
ance at a minimum.
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Chapter 1: Checklist of Laboratory Data
Compliance Monitoring Guidance
1. The method number of the base method used for the measurement.
The methods required for NPDES compliance monitoring are specified in 40 CFR
Part 136 (and elsewhere, as explained above). Although there are many similarities between
the technical details of methods from other EPA programs and from other sources, it is not
acceptable to use such other methods for NPDES monitoring in place of a 304(h) method.
For instance, methods from the Office of Solid Waste SW-846 manual are not acceptable in
instances where a 304(h) method exists, unless approved by the permitting authority in ad-
vance.
The 600- and 1600-series methods do provide flexibility to improve separations and
reduce the costs of measurements, but method performance must not be sacrificed. The
purpose of this flexibility is to allow for improvements in analytical technology, in part to
address matrix effects. In order to invoke this flexibility, the analyst must start with one of
the base 600- or 1600-series methods and improve upon it. Example improvements include
the use of additional cleanup techniques, alternative gas chromatography or liquid chromatog-
raphy columns, and more specific detectors.
Changing to an alternative method for the sake of convenience is contrary to the spirit
of this flexibility. The change must be within the scope of the method used and must be for
the sake of improvement, and this improvement must be supported by data demonstrating
equivalent performance to that of the base method.
2. A detailed narrative discussing the problems with the analysis, corrective
actions taken, and the changes made to the base method identified.
The permittee must also describe the reasons for the change to the base method, the
supporting logic behind the technical approach to the change, and the result of the change.
Many compliance monitoring analyses are performed by contract laboratories on
behalf of the permittee. However, the responsibility for providing the information to EPA
rests with the permittee. The permittee must therefore impress upon its contract laboratories
the need for detailed technical communication of problems encountered and solutions at-
tempted. The narrative should be authored by an analytical chemist and written in terms that
another analytical chemist can understand.
3. A summary level report or data reporting forms giving the pollutants for
which analyses were conducted and the concentrations detected. For the
pollutants that were not detected, the detection limits or estimated detection
limits must be provided.
Such results must be provided for each field sample analyzed, including any dilutions
and reanalyses.
* If not specified in the base method, the means for estimating detection limits must be
provided in the narrative. If the laboratory uses "flags" in its data reporting, the definition of
each flag must be provided with the data.
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Compliance Monitoring Guidance
Chapter 1: Checklist of Laboratory Data
4. A summary of all quality control results required by the base method.
These results include, but are not limited to, the following:
• Instrument tuning
• Calibration
• Calibration verification
• Initial precision and recovery
• Ongoing precision and recovery
• Matrix spike matrix spike duplicate results
• Surrogate recoveries
• Labeled compound recoveries (isotope dilution methods only)
• Blank results
• Quality control charts and limits
5. Raw data that will allow an independent reviewer to validate each deter-
mination and calculation performed by the laboratory.
This validation should consist of tracing the instrument output (peak height, area, or
other signal intensity) to the final result reported. The raw data are method specific and may
include any of the following:
• Sample numbers or other identifiers used by the both the permittee and the laboratory
• Extraction dates
• Analysis dates and times
• Sequence of analyses or run logs
• Sample volume
• Extract volume prior to each cleanup step
• Extract volume after each cleanup step
• Final extract volume prior to injection
• Digestion volume
• Titration volume
• Percent solids or percent moisture
• Dilution data, differentiating between dilution of a sample and dilution of an extract or
digestate
• Instrument(s) and operating conditions
• GC and/or GC/MS operating conditions, including detailed information on
columns used for determination and confirmation (column length and dia-
meter, stationary phase, solid support, film thickness, etc.)
analysis conditions (temperature programs, flow rates, etc.)
detectors (type, operating conditions, etc.)
• Chromatograms, ion current profiles, bar graph spectra, library search results
• Quantitation reports, data system outputs, and other data to link the raw data to the
results reported. (Where these data are edited manually, explanations of why manual
intervention was necessary must be included)
• Direct instrument readouts; i.e., strip charts, printer tapes, etc., and other data to
support the final results
• Laboratory bench sheets and copies of all pertinent logbook pages for all sample
preparation and cleanup steps, and for all other parts of the determination
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Chapter 1: Checklist of Laboratory Data
Compliance Monitoring Guidance
The raw data required shall be provided not only for the analysis of samples, but also
for all calibrations, verifications, blanks, matrix spikes and duplicates, and other QC analyses
required by the base method. Data must be organized so that an analytical chemist can
clearly understand how the analyses were performed.
Example calculations that will allow the data reviewer to determine how the
laboratory used the raw data to arrive at the final results.
Useful examples include both detected compounds and undetected compounds. If the
laboratory or the method employs a standardized reporting level for undetected compounds,'.
this should be made clear in the example, as should adjustments for sample volume, dry
weight (solids only), etc.
For GC/MS and other instruments involving data systems, the permittee
should be prepared to submit raw data on magnetic tape or disk, upon
request by EPA.
8. The names, titles, addresses, and telephone numbers of the analysts who
performed the analyses and of the quality control officer who will verify the
analyses.
If data are collected by a contract laboratory, it is the permittee's responsibility to see
that all of the requirements in the methods are met by the contract laboratory and that all data
listed above are provided. (See Chapter 6 for guidance on writing contracts for laboratory
services.)
Table 1. 600- and 1660-Series Methods for Organics1
Method
601
602
603
604
604.1
605
606
607
Class of Analytes
Purgeable Halocarbons
Purgeable Aromatics
Acrolein and Acrylonitrile
Phenols
Hexachlorophene and Dichlorophen
Benzidines
Phthalate Esters
Nitrosamines
Instrumentation
GC/ELCD
GC/PID
GC/FID
GC/FID, GC/ECD
HPLC/UV
HPLC/Electrochemical
GC/ECD
GC/NPD, ELCD
Status
Promulgated
Promulgated
Promulgated
Promulgated
Draft
Promulgated
Promulgated
Promulgated
1 Please note that other methods for the analysis of organic compounds are incorporated by
reference in 40 CFR 136.
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Compliance Monitoring Guidance
Chapter 1: Checklist of Laboratory Data
Table 1. 600- and 1660-Series Methods for Organics (cont.)
Method
608
609
610
611
612
613
614
614.1
615
616
617
618
619
620
621
622
624
625
626
627
629
630
630.1
631
632
632.1
633
Class of Analytes
Organochlorine Pesticides/PCBs
Nitroaromatics and Isophorone
Polynuclear Aromatic Hydrocarbons
Haloethers
Chlorinated Hydrocarbons
2,3,7,8-Tetrachlorodibenzo-p-
dioxin
Organophosphorus Pesticides
Organophosphorus Pesticides
Chlorinated Herbicides
C, H, and O Pesticides
Organohalide Pesticides/PCBs
Chloropicrin and Ethylene
Dibromide
Triazine Pesticides
Diphenylamine
Carbamate and Urea Pesticides
Organophosphorus Pesticides
Purgeable Organics
Base/Neutral and Acid Extractable
Organics
Acrolein and Acrylonitrile
Dinitroaniline Pesticides
Cyanazine
Dithiocarbamate Pesticides
Dithiocarbamate Pesticides
Benomyl and Carbendazim
Carbamate and Urea Pesticides
Napropamide, Propanil, and Vacor
Organonitrogen Pesticides
Instrumentation
GC/ECD
GC/FID, GC/ECD
HPLC/UV, Fluorescence
GC/ELCD/ECD
GC/ECD
Low Resolution GC/MS
GC/FPD
GC/NPD
GC/ECD
GC/FID
GC/ECD
GC/ECD
GC/NPD
GC/NPD
TLC
GC/NPD
GC/MS
GC/MS
GC/FID
GC/ECD
HPLC/UV
UV/Vis, by CS2 liberation
GC/Hall, by CS2 liberation
HPLC/UV
HPLC/UV
HPLC/UV
GC/NPD
Status
Promulgated
Promulgated
Promulgated
Promulgated
Promulgated
Promulgated
Proposed
Proposed
Proposed
Proposed
Proposed
Proposed
Proposed
Proposed
Draft
Proposed
Promulgated
Promulgated
Draft
Proposed
Proposed
Proposed
Proposed
Proposed
Proposed
Proposed
Proposed
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Chapter 1: Checklist of Laboratory Data
Compliance Monitoring Guidance
Table 1. 600- and 1660-Series Methods for Organics (cont.)
Method
633.1
634
635
636
637
638
639
640
641
642
643
644
645
646
680
1613
1618
1624
1625
1648
1649
1650
1651
Class of Analytes
Neutral Nitrogen-Containing
Pesticides
Thiocarbamate pesticides
Rotenone
Bensulide
MBTS and TCMTB
Oryzalin
Bendiocarb
Mercaptobenzothiazole
Thiabendazole
Biphenyl and Orthophenyl Phenol
Bentazon
Picloram
Amine Pesticides
Dinitro Aromatic Pesticides
Organochlorine Pesticides/PCBs
Polychlorinated Dibenzo-p-dioxins
and Dibenzofurans
Organochlorine Pesticides/PCBs,
Organophosphorus Pesticides, and
Phenoxy-Acid Herbicides
Volatile Organics
Semivolatile Organics
Organic Halides (OX) in Solids
Organic Halides (OX) in Solids
Adsorbable Organic Halides (AOX)
in Wastewaters
Total Oil and Diesel Oil in Drilling
Muds
Instrumentation
GC/NPD
GC/NPD
HPLC/UV
HPLC/UV
HPLC/UV
HPLC/UV
HPLC/UV
HPLC
HPLC/Fluorescence
HPLC/UV
HPLC/UV
HPLC/UV
GC/NPD
GC/ECD
GC/MS
High Resolution GC/MS
Isotope Dilution
GC/ECD, GC/NPD
GC/MS Isotope Dilution
GC/MS Isotope Dilution
Neutron Activation
Combustion, Coulometric
Titration
Carbon Adsorption, Com-
bustion, and Coulometric
Titration
Retort, Gravimetric
Status
Proposed
Proposed
Proposed
Proposed
Proposed
Proposed
Proposed
Proposed
Proposed
Proposed
Proposed
Proposed
Proposed
Proposed
Draft
Proposed
Draft2
Promulgated
Promulgated
Draft, 1/91
Draft, 1/91
Draft, 1/91
Proposed
2 Draft Method 1618 has been supplanted by Methods 1656, 1657, and 1658.
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Compliance Monitoring Guidance
Chapter 1: Checklist of Laboratory Data
Table 1. 600- and 1660-Series Methods for Organics (cont.)
Method
1652
1653
1654
1656
1657
1658
1659
1660
1661
Class of Analytes
Oil and Grease by Solid-Phase
Extraction
Chlorinated Phenolics in Wastewater
Diesel Oil in Drilling Muds
Organohalide Pesticides
Organophosphorus Pesticides
Phenoxy-Acid Herbicides
Dazomet
Pyrethrins and Pyrethroids
Bromoxynil
Instrumentation
Solid-Phase Extraction,
Gravimetric
GC/MS Isotope Dilution
HPLC
GC/ECD, GC/ELCD,
GC/Microcoulometric
GC/FPD
GC/ECD, GC/ELCD,
GC/Microcoulometric
GC/NPD
HPLC/UV
HPLC/UV
Status
Draft 12/91
Draft, 12/91
Draft, 12/91
Proposed2
Proposed2
Proposed2
Proposed
Proposed
Proposed
2 Draft Method 1618 has been supplanted by Methods 1656, 1657, and 1658.
To obtain copies of the 600-series methods, write To obtain copies of the 1600-series methods,
or call: write or call:
Chemical Research Division
USEPA Environmental Monitoring
Systems Laboratory
26 Martin Luther King Blvd.
Cincinnati, OH 45268
513-569-7325
USEPA Sample Control Center
(operated by Viar & Co.)
P. O. Box 1407
Alexandria, VA 22313
703-557-5040
Note: Some 1600-series methods listed as
"draft" may not be available through the Sample
Control Center.
Additional information on analytes, methods, and regulatory limits may be found in EMMI, the
EPA Environmental Monitoring Methods Index, a computerized database linking 50 EPA
regulatory lists, 2600 substances, and 926 analytical methods. For information on obtaining
the EMMI system software, contact:
National Technical Information Service
5825 Port Royal Road
Springfield, VA 22161
703-487-4650
Specify item number PB92-503093
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Chapter 2
Guidance for Analysts Attempting to Identify
and Quantify Pollutants in Wastewaters
Discharged from Plants Manufacturing
Organic Chemicals, Plastics, and Synthetic Fibers
This chapter provides guidance to analytical chemists having difficulty in analyzing complex
wastewaters from facilities that manufacture organic chemicals, plastics, and synthetic fibers. This
guidance illustrates how the method equivalency and flexibility permitted by the wastewater methods
can be used to apply other analytical techniques to matrix problems. This guidance specifically
addresses the determination of the organic pollutants in these wastewaters. Conventional pollutants
and metals are not addressed because few problems have been encountered in measuring these
analytes in these wastewaters.
Table 2, at the end of this chapter, lists the organic priority pollutants regulated in waste-
waters from organic chemicals, plastics, and synthetic fibers (OCPSF) industries and the EPA
analytical methods relevant to monitoring such wastewaters.
Approved Methods for Determination of Organic Pollutants
Section 304(h) and other sections of the CWA authorize the EPA Administrator to promulgate
test procedures for monitoring pollutants in wastewater discharges. Analytical methods (test proce-
dures) to monitor organic priority pollutants in wastewater were proposed on December 3, 1979 (44
FR 69494) and promulgated in 40 CFR Part 136 on October 26, 1984 (49 FR 43234). These methods
are variously known as the 304(h) methods, the 600-series methods, the 1600-series methods, and the
Cincinnati methods. Additional methods have been proposed and/or promulgated under Section
304(h) since 1984. The 304(h) methods for organics are listed in Chapter 1, Table 1. Information on
obtaining copies of these methods may be found at the end of that table.
The approved methods are based on recovery of organic pollutants from a wastewater sample
by a purge-and-trap technique or by extraction with an organic solvent such as methylene chloride.
In the purge-and-trap technique, the pollutants are purged from water with an inert gas and trapped on
a sorbent column. The sorbent column is then heated and back-flushed to desorb the pollutants into a
gas chromatograph (GC). The pollutants are separated by the GC and detected by a conventional
detector (CD) or by a mass spectrometer (MS). Conventional detectors include the flame ionization
detector (FID), electron capture detector (BCD), electrolytic conductivity detector (ELCD), and
nitrogen-phosphorous detector (NPD).
Pollutants extracted from wastewater with an organic solvent are concentrated by evaporation
of the solvent, and a portion of the concentrated extract is injected into a GC or high performance
liquid chromatograph (HPLC), where the pollutants are separated and detected by a CD or MS. For
application of GC and HPLC methods, EPA classified the organic pollutants into twelve groups of
similar chemical and physical properties allowing each group to be measured under a given set of
chromatographic conditions. Through the use of different detectors, several methods may be ap-
plicable to each of the twelve groups of pollutants. Table 3 lists the 304(h) methods applicable to
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Chapter 2: Guidance for Analysts
. Compliance Monitoring Guidance
monitoring those pollutants specifically regulated under the OCPSF Rule, provides the general class
of analytes to which the method is applicable, and specifies the applicable instrumentation.
Flexibility in Analytical Methods
In promulgating analytical methods for measurement of pollutants, EPA has provided flexibil-
ity for dealing with interferences. The major flexibility options are discussed in the preamble to the
40 CFR Part 136 methods (49 FR 43234). These options include a mechanism for obtaining approval
of an alternative test procedure on a nationwide basis and/or on a site-specific basis (40 CFR Parts
136.4 and 136.5). These procedures are intended to encourage development of new analytical
methods and to give analysts a number of options for resolving analytical problems that may be
unique to specific wastewaters. If the discharger or an interested third party wishes to pursue the
option of an alternative test procedure, that party should apply to the Director of the Environmental
Monitoring and Support Laboratory in Cincinnati, Ohio, for approval of an nationwide alternative
procedure, or should apply to the State or Regional EPA permitting office for approval of a limited
procedure.
In addition to the flexibility provided by the options above, flexibility is permitted in each
analytical method. The analyst is permitted to "improve separations or lower the costs of analyses"
provided that the results obtained are not less precise and accurate than the results obtained using the
unmodified method. For example, the analyst is allowed to use professional judgment in selecting
packed or open tubular columns, operating temperature programs, carrier gas or solvent flow rates,
and detectors. Analysts may also use their discretion in selecting cleanup procedures and extract
concentration procedures. The flexibility permitted is outlined in each method and in the preamble to
the regulation.
EPA believes that method flexibility, which is discussed further below, should permit pol-
lutant identities .and concentrations to be determined in nearly all wastewaters, but recognizes that
there may be a few intractable sample matrices that do not yield readily to extensive analytical efforts.
EPA is anxious to learn of the steps taken by the analyst, the solutions found, and the instances in
which a given matrix does not yield to known analytical techniques. Stating that "the sample couldn't
be analyzed" is not sufficient and will not be accepted as justification for a claim of matrix inter-
ference.
Demonstrating Equivalency with a Given Method
The objective in modifying a method is to make it more specific for a given pollutant, more
sensitive, more precise, more accurate, or in some other way to improve the method. However,
some laboratories have interpreted the provision to modify a method as a means of increasing the
speed of analysis, thus reducing the analysis time, or to take other "shortcuts" to reduce cost, result-
ing in a compromise of method performance. In regulating the wastewater methods, EPA needed a
means to preclude this compromise in performance, yet permit the flexibility that would improve
method performance.
EPA resolved this issue by providing limited flexibility within the methods, so that improve-
ments could be made, and requiring the analyst to demonstrate that the results produced by any
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Compliance Monitoring Guidance
Chapter 2: Guidance for Analysts
modification would be equal to or better than results obtained with the unmodified method. The
yardsticks by which this performance is to be measured are precision and accuracy, but can be
extended to include detection limit, gas chromatographic resolution, mass spectral resolution, and
other measures of method performance. The spirit of the regulation concerning methods is that
method performance must be improved by any modification, and must not be degraded by such a
modification.
The laboratory must perform a start-up test prior to practicing a method, and the results of the
start-up test must be on record at the laboratory for inspection by EPA if desired. The start-up test
provides an initial validation of the performance of the method by a specific laboratory. It is de-
scribed in detail in Section 8 of the 600-series and 1600-series wastewater methods and is also used in
the Office of Drinking Water 500-series methods and the Solid Waste SW-846 methods. The test
consists of an analysis of four replicate volumes of reagent water spiked with the pollutants of interest
at the concentration specified in the method or at 5-10 times the detection limit of the method.
For each analyte, the precision of the analysis of the four replicates, as determined by the
standard deviation of the four measurements, must be less than the standard deviation specified in the
method. Similarly, for each analyte, the accuracy of the analysis of the four replicates, as determined
by the average percent recovery of the four measurements, must fall within the range of percent
recovery specified in the method. If either the precision or accuracy test is failed, the test must be
repeated until the laboratory is able to meet the precision and accuracy requirements.
If the laboratory modifies a method, the start-up test must be repeated with the modification
as an integral part of the method. The laboratory must demonstrate that the precision and accuracy
specifications in the method can be met with the modification; otherwise, the modification is not
permitted. The laboratory must maintain records that document that the start-up test was performed
on the modified method and that the precision and accuracy requirements were met.
Examples of Solutions to Matrix Problems
The inability to measure the concentration of a pollutant in a specific wastewater is often
attributed to "matrix problems." Some example solutions to matrix problems are described below.
The list is not exhaustive but should help the analyst to examine the specific matrix problems at hand
and then to develop solutions to such problems.
Volatile Organic Pollutants
1. Use of selective GC detectors
The 304(h) methods for volatiles include Methods 601, 602, 603, 624, and 1624.
The effluent limits in the OCPSF regulation are all greater than 10 jtg/L. The selective GC
detectors in Methods 601 and 602 cover all OCPSF volatile pollutants regulated, and allow
detection at levels well below the effluent limits in the OCPSF regulation. The specificity
provided by the electrolytic conductivity detector and by the photoionization detector allow
detection of the halogenated and aromatic analytes, respectively, in complex matrices.
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Chapter 2: Guidance for Analysts
Compliance Monitoring Guidance
2. Micro-extraction and gas chromatography with selective detectors
The selective GC detectors in Methods 601 and 602 provide sensitivity that is 10-100
times greater than that required to detect the analytes of interest. Some of this sensitivity can
be used to substitute micro-extraction in place of purge-and-trap. The advantage of micro-
extraction is that the pH of the water can be adjusted to attempt to keep the interferences in
the water while the analytes of interest are extracted.1
3. Sample dilution
Methods 601 and 602 can achieve method detection limits of less than 1 jtg/L for all
volatile analytes in the OCPSF regulation, and of less than 0.1 /tg/L for many of these
analytes. The added sensitivity of the selective GC detectors can be used to overcome matrix
problems by diluting the sample by a factor of 10-100. Even with this dilution, the pollutants
can be detected at the levels required, and the effects of the interferences will be reduced or
eliminated.
4. Isotope dilution
Method 1624 employs stable, isotopically labeled analogs of the pollutants as internal
standards in the analysis. The use of these labeled compounds frequently permits the pol-
lutant to be determined in the presence of interferences because the unique spectrum of the
labeled compound can be located in the presence of these interferences, and the pollutant can
then be located by reference to the labeled compound.
Semivolatile Organic Pollutants
1. Use of selective GC detectors
Methods 604 through 612 employ gas chromatography with selective detectors and
high-performance liquid chromatography with an ultraviolet (UV) or electrochemical detector
to detect pollutants in the presence of interferences. In addition, Method 604 employs deriva-
tization and a halogen-specific detector for the determination of phenols. As with volatiles,
the added sensitivity of the selective detectors permits the sample to be diluted by a factor of
10-100 while allowing detection of the analytes at the effluent limits specified in the OCPSF
regulation.
2. pH change
A very powerful means of separating the pollutants of interest from interferences is to
adjust the pH of the sample to keep the interferences in solution while allowing the pollutants
to be extracted in an organic solvent. For example, neutral pollutants can be extracted at
either low or high pH. Therefore, if the main interferences are acidic, the pH can be adjusted
1 Rhodes, J.W., and Nulton, C.P., /. Env. Sci. and Health, vol. A15, no. 5, (1980).
12
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Compliance Monitoring Guidance
Chapter 2: Guidance for Analysts
to > 13 and the acidic interferences will remain in the water as their salts while the neutral
pollutants are extracted using an organic solvent.
Phenol and 2,4-dimethylphenol can be extracted at high pH (11-13) using continuous
liquid/liquid extractors, as described in Method 1625. This permits phenol and 2,4-dimethyl-
phenol to be extracted in the presence of other, stronger acids.2
In a manner analogous to the pH change described above, the extract from the pri-
mary extraction can be back-extracted with water of the opposite pH to remove other inter-
ferences. To keep the organic pollutants in the extract, the water used for back-extraction can
be saturated with salt (sodium sulfate and/or sodium chloride). Aqueous solutions containing
2% of each of these salts have been shown to be effective in keeping the pollutants of interest
in the extract.
6.
Gel-permeation (size-exclusion) chromatography
This technique is described in Revision C of Method 1625. The same technique is
used in the Superfund Contract Laboratory Program (CLP) methods and SW-846 methods,
and has been shown to be effective for removing lipids and high-molecular-weight interferen-
ces that can degrade GC and mass spectrometer performance.
Solid-phase extraction (SPE) cartridge
Although not fully evaluated at this time, SPE cleanup appears promising for not only
neutral species but also for acidic and basic species. It has been shown to be effective in
removing interferences from extracts containing pesticides and in the extraction of pollutants
from drinking waters by Method 525. 3
Florisil, alumina, and silica gel
These adsorbents are effective in separating neutral species from polar interferences.
For polar analytes of interest, the adsorbent must be evaluated to determine if the analyte will
be recovered. The level of activation of the adsorbent plays a major role in this recovery
process.
Isotope dilution
Method 1625 permits determination of pollutants in the presence of interferences in
semivolatile samples in the same way described for volatiles above. In addition, the wide
range of recovery of the labeled analogs permitted hi the method allows good quantitation of
the pollutant when interferences reduce the efficiency of the extraction.
2 Jackson, C.B. et. al., /. Env. Sci. and Health, vol. A15, no. 5, (1980).
3 Tessari, J.D., 12th Annual EPA Conference on Analysis of Pollutants in the Environment, Norfolk,
Virginia, May 1989 (copies of the proceedings may be available through the EPA Sample Control Center, P. O.
Box 1407, Alexandria, VA 22313, 703-557-5040).
13
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Chapter 2: Guidance for Analysts
Compliance Monitoring Guidance
Determination of Phenol as a Specific Example
Phenol is a commonly occurring pollutant in OCPSF wastewaters. The protocols below are
suggested as approaches to the determination of phenol in a complex sample matrix. After a protocol
has been found to be effective, the laboratory must demonstrate that the modification has equivalent
performance to the original method. This demonstration involves the start-up tests described above.
The specifications in the original method must be met before proceeding with analysis of a sample for
compliance monitoring.
1. Base/neutral extraction, acid back extraction, and isotope dilution GC/MS (based on Method
1625)
1.1 Measure 1.0 L of well-mixed sample into a graduated cylinder and spike with labeled
phenol per Section 10 of Method 1625. Stir and equilibrate per this method. Quan-
titatively transfer the sample to a continuous liquid/liquid extractor. Adjust the pH of
the sample to 11-13 and extract with methylene chloride as described in the method.
1.2 Remove the extract from the extractor and place in a 1-2 L separatory funnel. Back-
extract the extract sequentially three tunes with 500-mL portions of salt-saturated
reagent water (pH <2), discarding the reagent water after each back-extraction.
1.3 Concentrate the extract to 10 mL and clean up using gel-permeation chromatography
(GPC) per Section 10 of Method 1625.
1.4 After GPC, concentrate the extract to 0.5 mL and analyze by isotope dilution GC/MS,
as described in Method 1625.
1.5 Calculate the recovery of labeled phenol and compare to the performance specifica-
tions in Method 1625.
2. Dilution, acid extraction, back-extraction with base, derivatization, silica gel cleanup, and gas
chromatography with an electrolytic conductivity detector (based on Method 604)
2.1 Measure two 100-mL aliquots of well-mixed sample into 1000-mL graduated cylin-
ders. Spike one of the aliquots with phenol at the level specified in Section 8 of
Method 604. This aliquot serves as the matrix spike sample specified in the method.
Dilute both aliquots to 1.0 L with reagent water. Adjust the pH of each aliquot to
less than 2 with HC1.
2.2 Pour each aliquot into a separate 1-2 L separatory funnel and sequentially extract
three tunes with methylene chloride per Method 604. Discard the aqueous phase and
return the extract to the separatory funnel.
2.3 Back-extract the extract sequentially three tunes with salt-saturated reagent water, dis-
carding the reagent water after each back extraction.
2.4 Concentrate, derivatize, and clean up the extract per Method 604.
14
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Compliance Monitoring Guidance
Chapter 2: Guidance for Analysts
2.5 Analyze using the electrolytic conductivity detector. This detector is less susceptible
to interferences than the electron capture detector used in Method 604, Newer models
have sensitivity nearly equivalent to the electron capture detector.
2.6 Calculate the recovery of phenol in the matrix spike aliquot and compare this recovery
to the specifications in Method 604.
15
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Chapter 2: Guidance for Analysts
Compliance Monitoring Guidance
Table 2. Priority Pollutants Regulated under the OCPSF Rule
Priority Pollutant
Aoenaphthene
Acrylonitrile
Benzene
Carbon tetrachloride
Chlorobenzene
1 ,2,4-Trichlorobenzene
Hexachlorobenzene
1 ,2-Dichloroethane
1 ,1 ,1 -Trichloroethane
Hexachloroethane
1,1-Dichloroethane
1 ,1 ,2-Trichloroethane
Chloroethane
Chloroform
2-Chlorophenol
1 ,2-Dichlorobenzene
1 ,3-Dichlorobenzene
1 ,4-Dichlorobenzene
1 ,1-Dichloroethylene
1 ,2-trans-Dichloroethylene
2,4-Dichlorophenol
1 ,2-Dichloropropane
1 ,3-Dichloropropylene
2,4-Dimethylphenol
2,4-Dinitrotoluene
2,6-Dinitrotoluene
Ethylbenzene
Fluoranthene
Applicable 304(h)
Methods
610, 625, 1625
603, 624, 1 624
602, 624, 1624
601, 624, 1624
602, 625, 1625
612, 625, 1625
612, 625, 1625
601, 624, 1624
601, 624, 1624
612. 625, 1625
601, 624, 1624
601, 624, 1624
601, 624, 1624
601, 624, 1624
604, 625, 1625
601, 602, 612,
624, 625, 1625
601, 602, 612,
624, 625, 1625
601, 602, 612,
624, 625, 1625
601, 624, 1624
601, 624, 1624
604, 625, 1625
601, 624, 1624
601, 624, 1624
604, 625, 1625
609, 625, 1625
609, 625, 1625
602, 624, 1624
610, 625, 1625
Priority Pollutant
Methylene chloride
Chloromethane
Hexachlorobutadiene
Naphthalene
Nitrobenzene
2-Nitrophenol
4-Nitrophenol
2,4-Dinitrophenol
2-Methyl-4,6-Dinitrophenol
Phenol
Bis(2-ethylhexyl)phthalate
Di-/7-butyl phthalate
Diethyl phthalate
Dimethyl phthalate
Benzo(a)anthracene
Benzo(a)pyrene
3,4-Benzofluoranthene
Benzo(k)fluoranthene
Chrysene
Acenaphthylene
Anthracene
Fluorene
Phenanthrene
Pyrene
Tetrachloroethylene
Toluene
Trichloroethylene
Vinyl chloride
Applicable
304(h) Methods
601, 624, 1624
601, 624, 1624
612, 625, 1625
610, 625, 1625
609, 625, 1625
604, 625, 1625
604, 625, 1625
604, 625, 1625
604, 625, 1625
604, 625, 1625
606, 625, 1625
606, 625, 1625
606, 625, 1625
606, 625, 1625
610, 625, 1625
610, 625, 1625
610, 625, 1625
610, 625, 1625
610, 625, 1625
610, 625, 1625
610, 625, 1625
610, 625, 1625
610, 625, 1625
610, 625, 1625
601, 624, 1624
602, 624, 1624
601, 624, 1624
601, 624, 1624
16
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Compliance Monitoring Guidance
Chapter 2: Guidance for Analysts
Table 3. 304(h) Methods for OCPSF Organics
Method
601
602
603
604
606
609
610
612
624
625
1624
1625
Class of Analytes
Purgeable Halocarbons
Purgeable Aromatics
Acrolein and Acrylonitrile
Phenols
Phthalate Esters
Nitroaromatics and Isophorone
Polynuclear Aromatic Hydrocarbons
Chlorinated Hydrocarbons
Purgeable Organics
Base/Neutral and Acid Extractable
Organics
Volatile Organics
Semivolatile Organics
Instrumentation
GC/ELCD
GC/PID
GC/FID
GC/FID, GC/ECD
GC/ECD
GC/FID, GC/ECD
GC/FID/HPLC/UV,Fluorescence
GC/ECD
GC/MS
GC/MS
GC/MS Isotope Dilution
GC/MS Isotope Dilution
17
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Chapter 3
Cost Estimates
for Resolving Matrix Interferences
Most of the options for resolving matrix interferences are outlined in Chapter 2. The costs
associated with such options vary from laboratory to laboratory, as do the costs of the basic analysis.
However, EPA has provided some guidance in Table 4 on the likely added costs of the work required
to overcome such matrix interferences. These estimates are based on EPA's experience in contracting
for analytical services.
The costs are estimated for repetitive routine monitoring of a given waste stream. The esti-
mates do not include the development costs involved hi modifying a given method to overcome a
complex matrix problem. The cost estimates also do not include the costs of validating the use of
additional cleanup techniques through the "start-up" tests described in Chapter 2. The costs of
method modifications cannot be estimated because each complex matrix problem must be evaluated
individually. EPA believes that these development costs could range between several hundred and
several thousand dollars, depending on the complexity of the wastewater and the experience of the
laboratory in resolving matrix interferences.
Given these difficulties, EPA believes that the prudent course is to begin by applying the
cleanups and other techniques described hi Chapter 2 to the existing 304(h) methods before embarking
on a major modification of a method. The cost estimates in Table 4 are based on EPA's experience
through 1992 and are given in round numbers.
19
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Chapter 3: Cost Estimates
Compliance Monitoring Guidance
Table 4. Estimated Incremental Costs Associated with Cleanup Techniques
and Other Approaches to Resolving Matrix Interferences1
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Interference-reducing technique
Use of GC with selective detector in place
of GC/MS
Micro-extraction after pH adjustment
Sample dilution
Isotope dilution GC/MS (Method 1 624)
Use of GC with selective detector in place
of GC/MS
pH change
Back-extraction
Gel permeation cleanup
Solid phase extraction cleanup
Florisil column cleanup
Alumina column cleanup
Silica gel column cleanup
Sample dilution
Isotope dilution GC/MS (Method 1 625)
Estimated incremental cost
No increased cost:
should be less expensive than GC/MS
$25
No charge if known prior to analysis of neat
sample, otherwise may be billable as anoth-
er analysis
$200 to $500
No increased cost:
should be less expensive than GC/MS
No charge
$25
$100
$100
$25
$25
$25
No charge if known prior to analysis of neat
sample, otherwise may be billable as anoth-
er analysis
$200 to $500
The techniques listed in this table are discussed hi Chapter 2.
20
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Chapter 4
Guidance for Reviewing Data
from the Analysis of Organic Compounds
Using EPA 600- and 1600-Series Methods
This chapter provides guidance for reviewing data submitted for compliance monitoring
purposes under the National Pollutant Discharge Elimination System (NPDES) and data submitted to
EPA and State authorities under the Clean Water Act. This guidance is intended to aid in review of
data for organic compounds regulated under the OCPSF Rule and collected using the 600-series and
1600-series wastewater methods under 40 CFR Part 136 (49 FR 43234). The principles of data
review described herein are also applicable to data from the 500-series methods and the SW-846
methods.
The guidance is technically detailed and is intended for data reviewers familiar with the 600-
and 1600-series methods and similar analytical methods. Reviewers unfamiliar with these methods
should review the methods and the supporting background materials provided in the preamble to the
regulation (49 FR 43234).
Standardized Quality Assurance/Quality Control
In developing methods for the determination of organic pollutants in wastewater, EPA sought
scientific and technical advice from many sources, including EPA's Science Advisory Board, scien-
tists at EPA's environmental research laboratories, scientists in industry and academia, and scientists,
managers, and legal staff at EPA Headquarters. The result of discussions held among these groups
was the standardized quality assurance and quality control (QA/QC) approach that is an integral part
of the 600- and 1600-series methods. This QA/QC takes the form of performance specifications for
each, method and contains the following elements:
1. Purity and traceability of reference standards
2. Number of calibration points
3. Linearity of calibration
4. Calibration verification
5. Method detection limit (MDL) or rninimum level
6. Initial precision and recovery
7. Analysis of blanks
8. Recovery of analyte spikes into the sample matrix or
Recovery of labeled compound spikes into samples (Methods 1624 and 1625).
9. Statements of data quality for recovery of spikes of analytes or labeled compounds
into samples
10. Ongoing precision and recovery (Methods 1624 and 1625)
11. Statements of data quality for the laboratory
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Chapter 4: Data Review
Compliance Monitoring Guidance
In reviewing data submitted for compliance, the permit writer or other individual or organi-
zation has the authority and responsibility to assure that the test data submitted contain the elements
listed above; otherwise, the data can be considered noncompliant.
Provision of QA/QC Data
Permittees and other organizations submitting test data under the CWA or other acts may use
their own laboratories or contract the testing to laboratories that meet the requirements specified in the
methods. The permit writer can require that the supporting QA/QC data described above be submit-
ted with results or that it be on record at the permittee's facility or at the testing laboratory.
EPA strongly suggests that the supporting QA/QC data be submitted along with the analytical
results, so that the quality of the data can be evaluated directly, and so that these supporting data are
not lost between the time of submission of the analytical results and the time that the QA/QC data are
required.
In many of its early analytical programs, EPA relied upon laboratories to maintain records of
the QA/QC data. This practice was cumbersome for the laboratories, because many of the QA/QC
data were common to the analytical results for a variety of clients. Retrieving these data from the
laboratory to resolve questions of permit compliance was time-consuming for the permittee and the
permit writer. More importantly, this practice occasionally resulted in unscrupulous laboratories
failing to perform the necessary QA/QC testing, or performing the QA/QC testing "after the fact" to
satisfy an audit or data submission request. In particular, many laboratories did not perform the
initial precision and recovery test (the "start-up" test) prior to practice of the method and did not
perform a spike of the analytes into the sample matrix to prove that the method would work on a
particular sample. Therefore, while the data provided by those laboratories may have been valid,
there was no way to prove their validity.
When collecting data for the development of a regulation, EPA requires that the supporting
QA/QC data be provided along with the results for the sample analyses. If an individual or organi-
zation submits analytical results for inclusion into EPA's regulations, EPA similarly requires the
submission of the QA/QC data. The sample results are evaluated relative to the QA/QC specifica-
tions in the method, and those results that pass the QA/QC requirements are included for consi-
deration. EPA believes that provision of the QA/QC data at the tune of submission of the analytical
results is essential to the timely and effective evaluation of permit compliance issues.
Details of Data Review
The details of the data review process depend to a great extent upon the specific analytical
methods being employed for compliance monitoring. Even for data from the same methods, there are
probably as many specific approaches as there are reviewers. However, given the standardized
QA/QC requirements of the 600- and 1600-series EPA methods, a number of basic concepts apply.
The following sections provide the basic details for reviewing data submitted and provide some of
EPA's rationale for the QA/QC tests.
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Compliance Monitoring Guidance
Chapter 4: Data Review
Purity and Traceability of Reference Standards
The accuracy of any non-absolute empirical measurement is dependent on the refer-
ence for that measurement. In determining pollutants in water or other sample matrices, the
analytical instrument and analytical process must be calibrated with a known reference mate-
rial. The 600- and 1600-series analytical methods, as well as other EPA methods, require
that the standards used for calibration and other purposes be of known purity and traceable to
a reliable reference source.
The ultimate source for reference materials is typically EPA or the National Institute
for Standards and Technology (NIST, formerly NBS). Permittees and their supporting
laboratories submitting analytical data must be able to prove traceability of the reference
standards used in the analysis to EPA or NIST. The proof of this traceability is a written
certification from the supplier of the standard.
Documentation of the purity and traceability of the standards need not be provided
with every sample analysis. Rather, it should be maintained on file at the laboratory and
provided on request. When analyses are conducted in a contract laboratory, such documen-
tation ought to be provided to the permittee the first time that a laboratory is employed for
specific analyses and then updated as needed.
Number of Calibration Points
The 600-series methods specify a minimum of three calibration points. The lowest of
these points is required to be near the MDL. The highest is required to be near the upper
linear range of the analytical system, and the third point is approximately midway between the
two. Methods 1624 and 1625 require calibration at five specific concentrations for nearly all
analytes, and three or four specific concentrations for the remaining analytes for which the
methods are not as sensitive.
The lowest calibration point should never be greater than five times the MDL and
should ideally be within three times the MDL. The results for the lowest calibration standard
are the principal means by which to assure that measurements at levels near the MDL are
reliable.
The flexibility in selecting the levels of the calibration points in the 600-series meth-
ods has led to a wide variety of calibration ranges as each laboratory may determine its own
calibration range. Some laboratories establish a relatively narrow calibration range, for
instance a five-fold increase in concentration, because it makes it simpler to meet the linearity
specifications of the 600-series methods. Other laboratories choose wider calibration ranges
in order to minimize the number of samples that have to be diluted and reanalyzed because
the concentration of one or more analytes exceeds the calibration range.
The data reviewer must make certain that all measurements are within the calibration
range of the instrument. Samples with analytes outside of the calibration range should have
been diluted and reanalyzed. The diluted sample results need only apply to those analytes that
were out of the calibration range in the initial analysis. In other words, it is acceptable to use
data for different analytes from different levels of dilution within the same sample. Some
23
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Chapter 4: Data Review
Compliance Monitoring Guidance
flexibility may be exercised in acceptance of data that are only slightly above (< 10%) the
calibration range. Such data are generally acceptable as calculated.
If data from an analysis of the diluted sample are not provided, limited use can be
made of the data that are above the calibration range (> 10%). The response of the analytical
instrument to concentrations of analytes will eventually level off at concentrations above the
calibration range. While it is not possible to specify at what concentration this will occur
from the calibration data provided, it is generally safe to assume that the reported concen-
tration above the calibrated range is a lower limit of the actual concentration. Therefore, if
concentration above the calibration range is also above a regulatory limit, it is highly likely
that the actual concentration would also be above that limit.
3. Linearity of Calibration
The relationship between the response of an analytical instrument to the concentration
or amount of an analyte introduced into the instrument is referred to as the "calibration
curve." An analytical instrument can be said to be calibrated in any instance in which an
instrumental response can be related to a single concentration of an analyte. The response
factor (GC/MS methods) or calibration factor (GC, HPLC methods) is the ratio of the re-
sponse of the instrument to the concentration (or amount) of analyte introduced into the
instrument.
While the shape of calibration curves can be modeled by quadratic equations or higher
order mathematical functions, most analytical methods focus on a calibration range where the
response is essentially a linear function of the concentration of the analyte. The advantage of
the linear calibration is that the response factor or calibration factor represents the slope of the
calibration curve and is relatively constant, simplifying the calculations and the interpretation
of the data. Therefore, all the 600- and 1600-series methods specify some criterion for
deterrnining the linearity of the calibration curve. When this criterion is met, the calibration
curve is sufficiently linear to permit the laboratory to use an average response factor or
calibration factor, and it is assumed that the calibration curve is a straight line that passes
through the zero/zero calibration point. Linearity is determined by calculating the relative
standard deviation (RSD) of the response factor or calibration factor for each analyte and
comparing this RSD to the limit specified in the method. If the RSD does not exceed the
specification, linearity is assumed.
In the 600- and 1600-series methods, the linearity specification varies from method to
method, depending on the quantitation technique. The typical limits on the RSD are as
follows:
• 15% for the gas chromatography (GC) and high-performance liquid chromatography
(HPLC) methods
• 35% for analytes determined by the internal standard technique in the gas chromatog-
raphy/mass spectrometry (GC/MS) methods (624, 625, 1624, and 1625)
• 20% for analytes determined by isotope dilution in Methods 1624 and 1625
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Compliance Monitoring Guidance
Chapter 4: Data Review
If the calibration is not linear, as determined by the RSD of the response factor or
calibration factor, a calibration curve must be used;; This means that a regression line or
other mathematical function must be employed to relate the instrument response to the con-
centration. Properly maintained and operated lab instrumentation should have no difficulty in
meeting linearity specifications for 600- and 1600-series methods.
For determination of nearly all of the organic analytes using the 600- and 1600-series
methods, the calibration curves are linear over a concentration range of 20-100 times the
nominal concentration, depending on the detector being employed. Whatever calibration
range is used, the laboratory must provide the RSD results by which one can judge linearity,
even in instances where the laboratory is using a calibration curve. In instances where the
laboratory employs a curve rather than an average response factor or calibration, the data
reviewer should review each calibration point to assure that the response increases as the
concentration increases. If it does not, the instrument is not operating properly, or the
calibration curve is out of the range of that instrument, and data are not considered valid.
4. Calibration Verification
Calibration verification involves the analysis of a single standard, typically in the
middle of the calibration range, at the beginning of each analytical shift. The concentration of
each analyte in this standard is determined using the initial calibration data and compared to
specifications in the method. If the results are within the specifications, the laboratory is
allowed to proceed with analysis without recalibrating and use the initial calibration data to
quantify sample results.
Calibration verification, used in the 600- and 1600-series methods, differs in concept
and practice from "continuing calibration," which is used in the CLP and SW-846 methods.
In continuing calibration, a standard is analyzed and new response factors or calibration
factors are calculated on the basis of that analysis. If the new factors are close to the average
from the initial calibration, all subsequent sample analyses are conducted using the new
response or calibration factors. The degree of "closeness" is generally measured as the
percent difference between the old and new factors. The problem with continuing calibration
is that it amounts to a daily single-point calibration. Information about the behavior of the
instrument at concentrations above and below this single standard can only be inferred from
the initial multiple-point calibration.
Specifications for calibration verification are generally given as either a range of
concentrations or as a percentage difference from the test concentration. For the 600-series
semivolatile GC and HPLC methods, the difference must be within ±15%. For Method 625,
the difference must be within ±20%. For the GC and GC/MS methods for volatiles and for
Method 1625, a range of concentrations is given for each analyte. These ranges are based on
interlaboratory method validation studies.
If calibration is cannot be verified, the laboratory may either recalibrate the instru-
ment or prepare a fresh calibration standard and make a second attempt to verify calibration.
If calibration cannot be verified with a fresh calibration standard, the instrument must be
25
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Chapter 4: Data Review
Compliance Monitoring Guidance
recalibrated. If calibration is not verified, subsequent data are considered to be invalid until
the instrument is recalibrated.
Method Detection Limit or Minimum Level
The 600- and 1600-series methods do not require that laboratories determine the
method detection limit (MDL) for each analyte (40 CFR Part 136, Appendix B). However,
laboratories that wish to practice any method on a routine basis must prove that they can
measure pollutants at the MDL or the detection limit specified in the method. Performance of
an MDL study in accordance with this procedure is one means of demonstrating such profi-
ciency.
The ability to identify and quantify compounds at the "minimum levels" specified in
Methods 1624 and 1625 must be demonstrated prior to the practice of these methods. The
minimum level for any compound is the concentration in a sample that is equivalent to the
concentration of the lowest calibration standard in the initial calibration, assuming that all
method-specified sample weights, volumes, and procedures are employed. Therefore, data
from the initial calibration must be submitted in order to demonstrate that the required sen-
sitivity has been achieved.
If the minunum level in Methods 1624 and 1625 have not been achieved (as exempli-
fied by calibration data), data are considered to be invalid.
Initial Precision and Recovery
This test is required prior to the use of the method by the laboratory. It is sometimes
termed the "start-up test." The laboratory must demonstrate that it can meet the specifications
hi the method for the recovery of analytes spiked into a reference matrix (reagent water).
EPA's experience has been that laboratories that have difficulty passing the start-up test have
such marginal performance that they will have difficulty in the routine practice of the method.
Performing the start-up test "after the fact" is not acceptable and may not be used to validate
data that have been considered invalid because the start-up test was not performed.
The test consists of spiking the analytes of interest into a set of four aliquots of
reagent water and analyzing these four aliquots. The mean concentration and the standard
deviation of the concentration are calculated for each analyte and compared to the
specifications hi each method. If the mean and standard deviation are within the limits, the
laboratory can use the method to analyze field samples. For some methods, a repeat test is
allowed because of the large number of analytes being tested simultaneously.
If there are no start-up test data, or if these data fail to meet the specifications in the
method, all data produced by that laboratory using that method are not considered valid. As
with the documentation of the purity of the standards, the start-up test data need not be
submitted with each set of sample results, but should be submitted the first time a laboratory
is employed for analyses, and updated as changes to the method necessitate (see below).
It is important to remember that if a change is made to a method, the start-up test
must be repeated with the change as an integral part of the method. Such changes may
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Compliance Monitoring Guidance
Chapter 4: Data Revfew
involve alternative extraction, concentration, or cleanup processes, alternative GC columns,
GC conditions, or detectors, or other;steps designed to address a particular matrix problem.
If the start-up test is not repeated when these steps are modified or added, any data produced
by the modified method are considered not valid.
Analysis of Blanks
Blanks are required to be analyzed on a routine basis, when any part of the analytical
process has been changed, and when contamination of the laboratory is suspected. The 600-
and 1600-series methods require that a blank be prepared and analyzed with each set of
samples. The size of a "set" is usually limited to a maximum of 20 field samples. In practice
this means that on each day that a laboratory prepares samples, they must also prepare a
blank, even if fewer than 20 samples are prepared. The purpose of analyzing a blank with
each set of samples is to determine the extent of possible contamination of the samples while
in the laboratory. If the blank is handled by the same analysts in the same way as the samples
and the blank shows no contamination, it is likely that the samples will not have been con-
taminated. Requiring a blank be analyzed after the analytical process has been changed is
consistent with requiring a repeat of the start-up test, because the change introduces a new
possibility for contamination of samples through the use of the new procedures.
Contamination hi the laboratory is a common problem, though there are many opin-
ions on what constitutes contamination. In the 600- and 1600-series methods, any con-
centration of a compound above the detection limit or minimum level of the method in
question is a potential cause for concern. In reality, it is not unusual to find low levels of
common laboratory solvents, phthalates, and other ubiquitous compounds in laboratory
blanks.
Controlling laboratory contamination is an important aspect of each laboratory's
quality assurance plan. The laboratory should maintain records, typically in the form of
control charts, of blank contaminants. These records should prompt corrective action by the
laboratory, including reanalysis of any affected samples. Such control charts may be re-
quested by the reviewer in evaluating sample results; however, they are not routinely sub-
mitted with sample data.
Unfortunately, by the time that data on contaminants are submitted, it is usually too
late for corrective action. Therefore, the reviewer has several options in making use of the
sample data. First, if a contaminant is present in a blank, but not present in a sample, then
there is little need for concern about the sample result, though it may be useful to occasionally
review the raw data for samples without the contaminant to ensure that the laboratory did not
edit the results for this compound.
The second approach deals with instances where the blank contaminant is also report-
ed in a sample. Some general guidance will help you determine the degree to which the
contaminant is affecting sample results:
• If the sample contains the contaminant at levels of at least 10 tunes that in the blank,
then the likely contribution to the sample from the contaminant in the laboratory
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Chapter 4: Data Review
Compliance Monitoring Guidance
8.
environment is at most 10%. Since most of the methods in question are no more
accurate than that level, the possible contamination is negligible.
• If the sample contains the contaminant at levels of at least. 5 times but less than 10
tunes the blank result, the compound is probably present in the sample, but the nu-
merical result should be considered an upper limit of the true concentration.
• If the sample contains the contaminant at levels below 5 times the level in the blank,
there is no adequate means by which to judge whether or not the sample result is
attributable to laboratory contamination. The results for that compound in that sample
then become unacceptable for compliance monitoring.
There are two difficulties in evaluating sample results relative to blank contamination.
First, the reviewer must be able to associate the samples with the correct blanks. For analysis
of volatiles by purge-and-trap techniques, where no sample extraction is required, the blanks
and samples are associated by analysis date and time, and specific to the instrument as well.
For methods involving the extraction of organic compounds from the samples, the blanks and
samples are primarily associated by the date on which they were extracted, and by the batch
of samples and associated lab equipment (glassware, reagents, cleanup media).
The second difficulty involves samples that have been diluted. The dilution of the
sample with reagent water or the dilution of the extract with solvent represents an additional
potential source of contamination that will not be reflected in the results for the blank unless
the blank was similarly diluted. Therefore, in applying the 10-times rule, the concentration of
the sample is compared to the blank result multiplied by the dilution factor of the sample or
sample extract. For instance, if 12 ppb of a contaminant are found in the blank, and the
associated sample extract was diluted by a factor of 6 relative to the extract from the blank
prior to analysis, then the sample result would have to be greater than 12x6x 10, or 720 ppb,
to be acceptable. Between 360 ppb and 720 ppb, the sample result would best be considered
an upper limit of the actual concentration. Below 360 ppb, the sample result is not acceptable
for compliance monitoring.
Many laboratories would have the reviewer believe that subtracting the concentration
of the analyte in the blank from the concentration of the analyte in the sample is a reliable
method of determining the true concentration of the analyte in the sample. Unfortunately,
experience indicates that this practice is not reliable. The obvious problem occurs when the
blank concentration is higher than that in the sample, and subtraction would yield a negative
concentration value. Using the 10-times rule above provides a more appropriate means of
evaluating the results and does not require that the reviewer alter the results reported by the
laboratory.
Recovery of Analyte Spikes into the Sample Matrix or Recovery of Labeled Com-
pound Spikes into Samples (Methods 1624 and 1625)
The non-isotope dilution methods require a spike of the analytes of interest into a
second aliquot of the sample for analysis with the sample. The purpose of spiking the sample
(often termed a "matrix spike") is to determine if the method is applicable to the sample in
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Chapter 4: Data Review
question. The majority of the 600- and 1600-series methods were developed for the analysis
of effluent samples and may not be apprbpriate for in-process samples. While many of the
methods were tested using effluents from a wide variety of industries, samples from some
sources may not yield acceptable results. It is therefore important to evaluate method perfor-
mance in the sample matrix of interest.
If the recovery of the matrix spike is within the limits specified in the method, then
the method is judged to be applicable to that sample matrix. If, however, the recovery of the
spike is not within the recovery range specified, either the method does not work on the
sample, or the sample preparation process is out of control.
If the method is not appropriate for the sample matrix, then changes to the method are
required. Matrix spike results are necessary in evaluating the modified method. If the
analytical process is out of control, the laboratory must take immediate corrective action
before any more samples are analyzed.
To separate indications of method performance from those of laboratory performance,
the laboratory should prepare and analyze a quality control check standard consisting of a
spike of the analytes in reagent water. If the results for the quality control standard are not
within the range specified, then the analytical system must be repaired and the sample and
spiked sample analyses repeated. If the recovery of this spike is within the range specified,
then the analytical process is judged to be in control. However, the results of the sample
analysis cannot be accepted for regulatory compliance purposes because the matrix spike
results indicate that the method is not applicable to the sample.
In evaluating matrix spike results, the data reviewer must verify the following:
a.
b.
c.
d.
e.
The unspiked sample has been analyzed.
The spiked sample has been analyzed.
The recovery of the spike is within the range specified.
If the spike recovery is not within the range specified, a QC check standard
has been analyzed.
If a QC check standard has been analyzed, the results are within the range
specified.
For isotope dilution analyses, the evaluation of the data is simpler because isotopically
labeled analogs of the pollutants are spiked into each sample, and because a QC check stan-
dard (termed the "ongoing precision and recovery standard," or OPR) is analyzed with each
sample set.
If the recovery of the labeled compound spiked into the sample is not within the range
specified in the method, and the results of analysis of the ongoing precision and recovery
standard are within the respective limits, the sample results are considered invalid. When
labeled-compound recoveries are outside of the method specifications, the problem may be
.related to the sample matrix. The isotope dilution methods specify that, in these instances,
the sample must be diluted with reagent water and reanalyzed. If the labeled compound
recoveries meet the method specifications after dilution of the sample, then the results are
acceptable, although the sensitivity of the analysis will be decreased by the dilution.
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Unfortunately, for some sample matrices, even dilution will not resolve the problem,
and for other matrices, the loss of sensitivity will preclude the use of the results for deter-
mining compliance. In these instances, additional steps need to be taken to achieve acceptable
results. Guidance as to what steps may be taken when the results of matrix-spike or labeled-
compound recoveries are not within the limits specified in the methods is provided in Chap-
ter 2. This guidance consists of suggestions for more extensive extraction and cleanup proce-
dures, for sample dilution, and for other measures that can be taken to overcome matrix
problems.
Using either non-isotope dilution or isotope dilution techniques, in instances where
matrix spike or labeled compound recoveries are not within the specifications, it may still be
possible to use the sample results for compliance monitoring purposes. In particular, if (1)
the recovery of the spiked compound is above the method specifications and (2) the compound
is not detected in the sample analysis, it is unlikely that the compound is present in the
sample. This is because the factors that caused the analysis to over-estimate the concentration
in the spiked sample would not likely have resulted in an under-estimate in the unspiked
sample. For samples in which the compound is detected but the matrix spike or labeled
compound recovery is above the method specifications, the concentration reported in the
unspiked sample is likely an upper limit of the true concentration.
9. Statements of Data Quality for Recovery of Spiked Analytes or Labeled Compounds
in Samples
The 600- and 1600-series methods specify that after the analyses of five spiked
samples, a statement of data quality is constructed for each analyte. The statement of data
quality for each analyte is computed as the mean percent recovery plus and minus two times
the standard deviation of percent recovery for each analyte. The statements of data quality
should then be updated by the laboratory after each five to ten subsequent spiked sample
analyses.
For non-isotope dilution results, the statement of data quality can be used to estimate
the true value of a reported result and to construct confidence bounds around the result. For
example, if the result reported for analysis of phenol is 25 /*g/L, and the statement of data
quality for phenol is 70% ±30% (i.e., the mean recovery is 70% and the standard deviation
of the recovery is 15%), the true value for phenol will be in the range of 28-43 /*g/L, with
95% confidence. This range is derived as follows:
Lower limit = [(25 * 0.7) - (25 X 0.3)] = [35.7 - 7.5] =28 pg/L
Upper limit = [(25 - 0.7) + (25 x 0.3)] = [35.7 + 7.5] =43 pg/L
Many laboratories do not provide the data quality statements with the sample results,
in which case the data reviewer must determine if the data quality statements are being
maintained for each analyte and may need to obtain the data. If necessary, the reviewer can
construct the data quality statement from the individual data points.
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Compliance Monitoring Guidance
Chapter 4-: Data
Statements of data quality for isotope dilution methods are based on the recoveries of
the labeled compounds. Using an isotope dilution method, the sample result has already been
corrected for the recovery of the labeled analog of the compound. Therefore, for a reported
result for phenol of 25 /ig/L where the standard deviation of the labeled phenol recovery is
15%, the true value for phenol will be in the range of 17-32 /ig/L, with 95% confidence,
derived as follows:
Lower limit = [25 - (25 x 0.3)] = 17 /ig/L
Upper limit = [25 + (25 x 0.3)] = 32 /tg/L
The lack of a statement of data quality does not invalidate results but makes some
compliance decisions more difficult. If statements of data quality are not being maintained by
the laboratory, there may be increased concern about both specific sample results and the
laboratory's overall quality assurance program.
10. Ongoing Precision and Recovery (Methods 1624 and 1625)
Methods 1624 and 1625 require that an "ongoing precision and recovery" (OPR)
standard be analyzed with each sample set, and that the results of this standard meet the
acceptance criteria in the method prior to the analysis of blanks and samples.
The data reviewer must determine if the ongoing precision and recovery standard has
been run with each sample set and if all criteria have been met. If the standard was not run
with a given set of samples, or if the criteria are not met, the results for that set of samples
are considered not valid.
For volatiles analyses by Method 1624, the OPR analysis is associated with the
samples on the basis of the analysis date and time and the specific GC/MS system. For
semivolatile analyses by Method 1625, OPR results are associated with samples extracted at
the same time as the OPR.
Because of the large number of compounds being tested simultaneously in the 600-
and 1600-series methods, there is a small probability that the OPR analysis will occasionally
fail to meet the specifications. While the laboratory is supposed to correct any problems and
analyze another OPR aliquot, it may still be possible to utilize the data associated with an
OPR aliquot that does not meet all of the method specifications.
For instance, if the concentration of a compound in the OPR is above the method
specifications but that compound is not detected in an associated sample, then it is unlikely
that the sample result is affected by the failure hi the OPR. If the concentration in the OPR is
below the method specifications but that compound is detected in an associated sample, then
the sample result is likely a lower limit of the true concentration for that compound.
11. Statements of Data Quality for the Laboratory (Methods 1624 and 1625)
In addition to statements of data quality for results of analyses of the labeled com-
pounds spiked into the samples, Methods 1624 and 1625 require that statements of data
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quality be constructed from the initial and ongoing precision and recovery data. The purpose
of these statements is to assess laboratory performance in the practice of the method, as
compared to the assessment of method performance made from the labeled compound results
for the samples. Ideally, the two statements of data quality would be the same. Any dif-
ference is attributable to either random error or sample matrix effects.
If the laboratory is practicing isotope dilution methods, the data reviewer should
review the statements of data quality for the laboratory. If the laboratory does riot make these
statements available for the reviewer, they may be requested. If the laboratory still does not
make them available, it does not necessarily invalidate any data, but indicates that the labora-
tory may not be following the method as written.
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Chapter 5
Case Histories
of Claims of Matrix Interferences
Submitted Under the OCPSF Rule
Chapter 1 described the data that would be required to demonstrate that a matrix problem
precluded the measurement of a pollutant regulated under a NPDES permit limitation. This chapter
provides case histories of selected claims of matrix interference problems submitted by dischargers
regulated under the OCPSF rule.
Since 1991, the Engineering and Analysis Division (BAD) of EPA has reviewed data provided
by at least 15 dischargers regulated under the categorical pretreatment standards for the OCPSF
industry. In each instance, the discharger claimed that the facility's wastewater could not be moni-
tored for compliance with the pretreatment standards because of interferences. BAD was asked to
review such claims of matrix interferences by either the Region or State with permitting authority for
the facilities in question. The various guidance documents collected here under one cover are an
offshoot of the efforts to review such claims.
EAD's review focused on each facility's alleged inability to determine the organic analytes in
its wastewater because of interferences. This chapter presents 11 case histories of EAD's review of
data submitted by dischargers claiming interference problems and provides further detail as to how
these dischargers might resolve matrix interference problems. None of the dischargers nor any of the
laboratories involved are identified in this document.
Prior to reviewing the data, each of the permitting authorities was provided with copies of the
following draft guidance documents:
• Draft Checklist of Laboratory Data Required to Support a Claim that the Permittee
was Unable to Measure Pollutants Due to Matrix Problems .(the "Checklist," updated
as Chapter 1 of this report)
• Draft Guidance for Analysts Attempting to Identify and Quantify Pollutants in Was-
tewaters Discharged from Plants Manufacturing Organic Chemicals, Plastics, and
Synthetic Fibers (the "Guidance for Analysts," updated as Chapter 2 of this report)
• Draft Guidance for Permit Writers and Others Reviewing Data from the Analysis of
Organic Compounds Determined using the 600- and 1600-series Methods (the "Guid-
ance for Permit Writers," updated as Chapter 4 of this report)
It was EAD's intention that these draft documents be provided to the dischargers and in turn
to their laboratories, as needed. However, the review revealed that the documents had either not been
provided by the States and Regions or were not followed.
In general, EAD's review of the claims submitted by 11 dischargers revealed the following:
• In nearly all instances where data were submitted, the dischargers and/or their con-
tract laboratories were using incorrect analytical methods or did not follow the proce-
dures required in 40 CFR Part 136.
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Chapter 5: Case Histories
Compliance Monitoring Guidance
In other instances, the dischargers and/or their contract laboratories did not submit
data necessary to document that the methods were being followed.
Finally, the dischargers and/or their contract laboratories did not submit documen-
tation regarding the nature of interferences and the attempts (if any) to resolve these
interferences.
Case Histories
Case #1: This discharger used a contract laboratory for its analytical work. Informa-
tion submitted by the laboratory revealed inconsistencies with the stated
analytical methods.
The discharger allowed the laboratory to either
(1) Use alternative methods to the 40 CFR Part 136 methods, or
(2) Modify Methods 624 and 625.
Alternative methods are allowed under 40 CFR Part 136.4 and 136.5 provided that the facility
submits the alternative methods to EPA's Environmental Monitoring and Support Laboratory in
Cincinnati, Ohio, (EMSL-Ci) for approval. Otherwise, alternative methods are not allowed. BAD
found no reference to alternate methods approved by EMSL-Ci.
If Methods 624 and 625 were modified under the spirit of the 40 CFR Part 136 rule, these
modifications were not documented and equivalence was not demonstrated. Modifications that the
laboratory made to Methods 624 and 625 included:
• Combining acid and base/neutral fractions,
• Using a fused-silica capillary column for the analysis of acid and base/neutral frac-
tions,
• Using alternative internal standards,
• Using alternative surrogates,
• Using higher detection limits,
• Using fewer matrix spike compounds, and
• Using matrix spike amounts inconsistent with regulatory compliance, background, or
method-specified levels.
The preamble to the 40 CFR Part 136 methods (49 FR 43234, October 26 1984) states that a
method is considered to be equivalent if its performance has been demonstrated to meet or exceed the
specifications hi the original method. None of the submitted data provided any evidence supporting
method equivalence.
EPA recognizes that the use of multiple internal standards and a fused-silica capillary column
for the base/neutral/acid fraction represent improvements; however, EPA does not accept that com-
bining fractions, higher detection limits, alternative matrix spike compounds, and matrix spike
amounts inconsistent with background or regulatory compliance levels represents improvement. On
the contrary, these changes degrade method performance and are therefore in violation of both the
spirit and letter of the flexibility permitted in the 600- and 1600-series 40 CFR Part 136 organic
methods.
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Compliance Monitoring Guidance
Chapter 5: Case Histories
Method 625 requires the analysis of separate acid and base/neutral fractions (40 CFR Part
136, Appendix A: Method 625, Sections 10 arid 12 and Tables 4 and 5). Because combining these
fractions can compound matrix interference problems, the acid and base/neutral fractions should not
have been combined for these analyses.
The matrix spike compounds and spiking levels used by the laboratory appeared to have been
from Office of Solid Waste (OSW) SW-846 methods or from Superfund Contract Laboratory Program
(CLP) methods. The 600- and 1600-series wastewater methods require the matrix spike compounds
to be the compounds regulated in the discharge (e.g., 40 CFR Part 136, Appendix A: Method 624,
Section 8.3) and require that the spike levels be at
(1) The regulatory compliance level,
(2) 1-5 times the background level of the analyte in the sample, or
(3) The level specified in the method (e.g., Method 624, Section 8.3.1).
The compounds spiked were not those regulated and the spikes were not at the levels required.
The matrix spike was performed on a diluted sample. Had the matrix spike been performed
as specified in Method 624 or 625 (e.g., Method 624, Section 8.4.3), the spike would likely have
failed the specifications in the method and the associated sample result could not have been reported
for regulatory compliance purposes. This should have triggered cleanup procedures, the use of
alternative methods, or modification of Method 624 or 625 to improve method performance, as
detailed in the draft "Guidance for Analysts."
The QC specifications for matrix spike recovery used by the laboratory were not the specifica-
tions given in Methods 624 and 625. The specifications in the wastewater methods (40 CFR Part
136, Appendix A: Method 624, Table 5; and Method 625, Table 6) must be used for compliance
monitoring. While tighter specifications from a documented source may be acceptable if met, use of
wider limits without documentation would never be acceptable.
The detection limits reported for semivolatiles were, for the most part, twice the minimum
levels given in Method 1625 and were approximately 10-20 times the method detection limits (MDLs)
given in Method 625. No explanation for the increased detection limits was given, nor could the
limits be derived from the data provided.
The laboratory made no attempt to clean up the samples using pH change, gel permeation
chromatography, or the other techniques in the 600- and 1600-series methods or the draft "Guidance
for Analysts."
Case #2: Information provided with data submitted by this discharger was insufficient
for a detailed review, (as outlined in the "Checklist of Laboratory Data").
Despite the general lack of data, it appeared the discharger submitted samples to a contract
laboratory for analyses by a GC/MS method which failed to produce useful results. The discharger
and/or the laboratory attributed the problems to large concentrations of acetone in the discharge,
though this problem could not be confirmed from the information provided. The analytical contractor
proposed to the discharger that Methods 601 and 602 be used for the volatiles analysis in an attempt
to overcome the interference problems. Because these methods are both more sensitive and more
selective than a GC/MS method, the analytes regulated should be measurable in the presence of a
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Chapter 5: Case Histories
Compliance Monitoring Guidance
large concentration of acetone. The discharger ignored the laboratory's proposal and submitted a
claim of matrix interferences. EPA believes that the approach proposed by the laboratory is workable
and appropriate, and should have been attempted. If Methods 601 and 602 were used (as with any
other methods used), the analytical laboratory must adhere to all method specifications.
Case #3: This discharger used several contract laboratories for analyses. The "re-
ports" from these laboratories consisted of summary reporting forms show-
ing detection limits that were 10-50 times greater than the MDLs in Meth-
ods 624 and 625.
'•','*'
There were no QC results, no details of how the analyses were performed, and no documen-
tation of interference problems or steps taken to overcome interference problems, and therefore no
proof that an interference existed. The laboratory may have chosen to dilute samples for conven-
ience. The discharger and its laboratory must provide the data listed in the "Checklist of Laboratory
Data" and attempt to solve purported interference problems using the techniques discussed in the
"Guidance for Analysts."
Case #4: This discharger submitted a report from one contract laboratory that con-
tained insufficient information for evaluation; and two letters from a second
contract laboratory describing a problem with 4,6-dinitro-o-cresol.
The report provided by the first laboratory indicated no results for spikes of the OCPSF-
regulated analytes into samples, no details of how the analyses were performed, what interference
problems were encountered, or what steps were taken to overcome interference problems. In ad-
dition, it appeared that the contract laboratory combined acid and base/neutral extracts, thus exacer-
bating interference effects.
The letters from the second laboratory describing the problem with 4,6-dinitro-o-cresol asked
for suggestions on how to determine this compound in the presence of interferences. The "Guidance
for Analysts" provides general suggestions for overcoming matrix interference problems and specific
suggestions for determination of phenol. The specific suggestions for determination of phenol can be
applied to 4,6-dinitro-o-cresol.
Other reports by the contract laboratory showed high detection limits for the substituted
phenols because of a huge quantity of phenol hi the sample. One solution to this analytical problem is
for the facility to reduce the level of phenol hi the wastewater. The analytical laboratory should have
used the procedures for determination of phenol detailed in the "Guidance for Analysts."
Case #5: This discharger submitted letters and reports from several contract labora-
tories. One report contained only some of the data required by the "Chec-
klist of Laboratory Data."
Data items that were present and are required for a thorough review were instrument tunes,
run chronologies, chromatograms, calibration data, calibration verification data, results for blanks,
quantitation reports for samples, and matrix spike data run against the QC limits for Methods 624 and
625. The initial precision and recovery (IPR) data that demonstrate method equivalence were mis-
sing.
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Compliance Monitoring Guidance
Chapter 5:
The semivolatile matrix spike data were inconsistent. The results of the unspiked samples
indicated that some of the acids and base/neutrals were not detected, yet the results for the spiked
samples showed large concentrations of some of these analytes that were not spiked into the samples.
The volatiles matrix spike had been diluted by a factor of 200 and spiked after dilution.
Diluting and spiking will not show matrix interferences, and thus these data are of no value in
evaluating the undiluted sample results.
Cases #6-#11: These facilities submitted summary reports from their laboratories.
None of the materials contained the information required by the "Checklist of Laboratory
Data," and none contained explanations of the nature of the interferences found or descriptions of
attempts to overcome these interferences. These facilities should follow the guidance provided by
EPA and should report all data required by the "Checklist of Laboratory Data" and the "Guidance for
Permit Writers."
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Chapter 6
Guidance on Contracting
For Analytical Services
Most businesses and government organizations have procedures and policies governing the
purchase of services and supplies. They range from simply assigning responsibility to one individual
("Joe handles all that...") to the myriad of complex procedures set forth in the Federal Acquisition
Regulations (FAR). Once established, these various procedures and policies may be applied relatively
easily to purchases of office supplies, computers, and janitorial services. However, most organi-
zations experience problems when they attempt to apply these procedures to the purchase of analytical
services.
At the heart of these problems is the difficulty in defining the services that are required. The
purpose of this chapter is to provide a basic framework with which to define the technical and con-
tractual requirements associated with purchasing analytical services related to compliance monitoring
under the National Pollutant Discharge Elimination System (NPDES). The procedures outlined here
are presented as guidance and may need to be modified to meet the specific policies of an organi-
zation. The level of detail presented is not sufficient to meet all of the requirements of the FAR, but
is a subset of the procedures used by several EPA offices and their contractors. The procedures may
represent some degree of "overkill" for private organizations; however, it is simpler to delete the
unneeded detail in those instances than to add it when it is required. The procedures are designed for
procuring analytical services from commercial laboratories, but may also be applied to requests for
services from in-house laboratories.
Requirements Analysis
Defining what services are required is often the most difficult step. The commercial environ-
mental laboratory business has grown to be a multi-million-dollar-per-year enterprise serving the
diverse needs of clients regulated under a variety of federal and state environmental statutes. Many
laboratories have recognized the importance of customer service and employ staff who are trained to
assist clients in defining the requirements. Other laboratories, large and small, rely solely on the
client to define the specific requirements. Still another group of laboratories, albeit a small group,
perform analyses with little regard to the client's actual needs. One of the problems that arises when
the client's requirements are poorly defined is the use of inappropriate methods. As noted in Chap-
ter 1, NPDES compliance monitoring requires that the 304(h) methods be used. It is not the labora-
tory's place to decide that a method from another source, even another EPA source, is "close
enough."
The "five W's" of journalism ("who, what, when, where, and why," with "how" thrown in
for good measure) are a first step in defining the requirements. "Who" is the name of the client,
including a set of specific contact points. The laboratory needs to know the name of the person who
will be taking and shipping the sample, in the event that there are shipping delays, broken samples,
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Chapter 6: Contracting
Compliance'Monitoring Guidance
etc. The laboratory needs the name of a technical contact, if any, in the event that there are analy-
tical questions that need to be resolved. The laboratory also needs to know the name of the admini-
strative contact who will handle issues of billing, payment, etc.
"What" is a description of the samples to be analyzed, including:
• Number of samples,
• Matrices (e.g., wastewater, sludge, solids, soils, etc.), and
• Analyses required (volatile organics, pesticides, etc.). •
"What" may also include information on the required methodology, the reporting format, and the
quality assurance/quality control (QA/QC) requirements. It may also include a specific description of
the "product" to be delivered to the client. EPA recommends (Chapter 4) that the client receive a
copy of all data, raw and summary, associated with the analyses.
"When" specifies the approximate date that the samples will be shipped to the laboratory,
including the means of shipment (hand-delivered, picked up by the laboratory, overnight air freight,
etc.), and the date when the results are required by the client. It should also specify the date by
which the results are required. The "turnaround time" is the length of time, usually in calendar days,
from the receipt of the sample at the laboratory until the results are to be received by the purchaser.
The turnaround tune is often a function of a reporting deadline under a permit. One can often save
cost by giving the laboratory as much tune as possible to provide the data. Sampling early in the
month may mean that one has more tune before the data must be reported to the permitting agency.
Obviously, "where" includes the name of the laboratory, but it is important to include the
street address of the laboratory to which the samples will be shipped and the name of the person
assigned to receive the samples. It is also important to include the name and address of the labora-
tory's administrative personnel handling billing and payment issues, as these may be different from
the address where samples are shipped.
"Why" is often overlooked by people who assume that everyone understands the purpose of
the analysis. Simply stating that "the analysis of X wastewater samples for NPDES compliance
monitoring is required" can give a laboratory a wealth of information. Among other things, it should
inform the laboratory that a 304(h) method is to be used; however, just to be certain, the method
required is also specified elsewhere (see "how" below). In contrast, a statement about "ground-water
monitoring" ought to lead the laboratory to inquire as to the purpose of the analysis, and hence what
methods might be required, as 304(h) methods may not be appropriate. The type of analyses required
can also be included, further clarifying the requirements.
The last requirement to be explicitly stated is "how." Although information about the
analysis is included in "what" and "why," it helps to be specific, stating the method that is required
or requested. It is also important to specify the quality assurance and quality control operations that
will be performed in association with the sample analyses. While the EPA 600- and 1600-series
methods specify the level of QA/QC to be performed, there are some methods from other sources
(SW-846, ASTM, AOAC, etc.) that have been approved under Section 304(h) for some analytes, and
these methods may not be as explicit regarding the QA/QC requirements. The laboratory also needs
to know how the data are to be reported and how many copies of the report are required.
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Compliance Monitoring Guidance
Chapter 6: Contracting
Identifying Laboratories and Soliciting Bids
Identifying qualified laboratories can be a time-consuming process. While many laboratories
advertise in the Yellow Pages and in various directories of professional services, those advertisements
may not tell you much about the laboratory's abilities to fulfill your specific analytical requirements.
However, any list of laboratories is better than none. In addition, state and EPA Regional personnel
may be able to give you a list of laboratories in your area or nationwide, depending on the type of
analyses required. Such lists are not an endorsement of these laboratories, but are provided as a
starting point.
If your procedures require that you obtain competitive bids for laboratory services, you will
Usually have to identify a minimum of three laboratories from which to solicit bids. If you are not
required to obtain competitive bids, it may still be useful to occasionally compare prices from compe-
ting laboratories.
Determining that a laboratory is qualified to perform the analyses is also a somewhat daunting
task. You can always take the laboratory director's word for their capabilities. However, you then
have to evaluate the consequences of making a error in judgment. While EPA is currently exploring
the idea of a national laboratory accreditation program, it is unlikely that such a program will be in
place for several years. In the meantime, you can begin to identify qualified laboratories by sending
them a list of your requirements, identified above. Ask them to provide information regarding their
qualifications to perform such work (SOQ). Obviously, this needs to be done well in advance of your
need for actual analytical services. The laboratory should be willing to discuss your specific needs
with you, and demonstrate how they will meet those needs. While not normally required for NPDES
compliance monitoring, it is not unheard of to perform an on-site inspection of a laboratory prior to
using their services. It may also be worthwhile in some instances to send performance evaluation
samples (samples of known composition) to a laboratory prior to utilizing them for routine analytical
work. Performance evaluation samples for various organic and inorganic analytes are commercially
available from several vendors. These vendors may also prepare custom samples that focus on the
regulated pollutants at a specific facility.
Once you have identified a group of laboratories, you may solicit bids by simply sending
them a request for a bid, including the detailed requirements identified above. One possible format
for such solicitations is included with this report as an attachment. This is a generic version of a
format that several EPA contractors have used for some time.
The NPDES compliance monitoring requirements for a given facility may only require the
analysis of a small number of samples monthly or quarterly. While those analyses are very important
to you (the discharger), they may not represent a significant source of revenue for a given laboratory.
At some level, you are paying for all the quality control analyses associated with your small number
of samples. As a result, you may pay higher prices per sample. One way to address the cost issue is
to pursue a longer-term contracting arrangement. Determine how many analyses of what types you ,,
will need for the next year, and ask laboratories to .bid on the entire package. To do this, you must
be able to approximate the schedule on which these analyses are needed, but that is often driven by
permit requirements. The advantages to you are (1) a lower price and (2) less time spent arranging
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Chapter 6: Contracting
Compliance Monitoring Guidance
for bids. The advantages to the laboratory are (1) knowing that the work is coming and (2) spending
less time getting business.
Writing a Contract
Before writing a contract for any kind of services, consult with the appropriate legal staff at
your facility or firm. They will obviously know the ins and outs of contract law in your state. A
well-written contract will include the "five W's" outlined above. It will also address your right to
review the data as needed, the timeliness of payment to the laboratory, and your ultimate right to
determine that the work does not meet the requirements established in the contract.
The required data turnaround and analytical holding time must be stated clearly in the
contract. If analytical holding times are applicable, they are generally stated in the analytical method.
However, delays in sampling and sample shipment may necessitate specification of a "contract"
holding time that is based on the analytical holding time minus any time required for sample ship-
ment. Unless you can guarantee that the sample will be delivered as soon as the laboratory opens in
the morning, it is typical to specify that the day that the sample is received at the laboratory is "day
zero," and the counting of "days" begins with the following day as "day 1."
In addition to stating the time that the laboratory has to generate and deliver the data, it may
be useful to assign some specific consequences to the possibility of late delivery. One approach is to
assess a penalty of some percentage of the analytical price per day of lateness. In the past, EPA has
used values of 1-2% per day after the due date that the data were delivered.
Obviously, such penalties for lateness cannot be due to changes in the requirements made
after the samples were sent, or the fact that the methods requested were not applicable to the samples.
Many of the remedies to matrix problems discussed in Chapter 2 cannot be expected to be carried out
in the original turnaround time assigned to the sample. However, once you have established that your
samples can routinely be analyzed by the requested methods, lateness becomes an issue of laboratory
management practices, not sample matrix.
From time to time, almost every laboratory will produce data that are of little use for the
intended purpose (compliance monitoring hi this instance). While well-run laboratories will contact
you as soon as they identify the problem and work with you to make the best of a bad situation, you
may still find yourself with no useful data and a deadline approaching.
A contract should stipulate that the laboratory will reanalyze samples at no cost to the client if
the problems are due to laboratory error. It should also state that the client has the right to inspect
the results, and if they do not meet the requirements in the contract, the client has the right to reject
the data, returning them to the laboratory without payment. Rejection of data should be based on
sound technical review of the results. It also obligates the client to make no use of those results
without making some payment to the laboratory.
The contract should discuss in what instances dilutions of samples and reanalyses are con-
sidered billable by the purchaser. Again, a laboratory should be prepared to do the job right the first
time and not bill for reanalyses required due to their errors. In contrast, some samples may need to
be diluted and reanalyzed in order to bring the results within the demonstrated calibration range of the
instrumentation. When this occurs, the laboratory ought to be paid for this effort. Such reanalyses
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Compliance Monitoring Guidance
Chapter 6: Contracting
can be figured into the original price, inflating the per-sample price for all samples to account for the
need to reanalyze some samples, or it can be broken out as a separate cost. Similarly, for analyses
involving an extraction or digestion as well as an analysis, it may be useful to specify the price for
the extraction step and the analysis separately, as a reanalysis may not require an additional extrac-
tion.
The contract is not a one-sided agreement, and as such, it must give specific rights and
recourse to the laboratory as well. You may be asked to negotiate specific contract issues with the
laboratory beforehand. The time involved in this process will obviously vary, and one of the benefits
of contracting over longer time periods than the immediate need for one analysis is that these negotia-
tions need only take place once for a large number of samples.
Combined with a careful analysis of the requirements, a well-written contract can minimize or
eliminate many common problems in procuring analytical services. It should enable the client to
obtain technically sound, legally defensible, and timely analytical data to meet a variety of compliance
monitoring needs.
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