Monitoring Trace Metals at
Ambient Water Quality
Criteria Levels
Briefing Book
January 1995
William A. Telliard, Chief
Analytical Methods Staff
Engineering and Analysis Division
Office of Science and Technology
Office of Water
vvEPA
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Table of Contents
Section 1- Monitoring Trace Metals at Ambient Water Quality
Criteria Levels: Issues, Plans and Schedule
Section 2- Method 1669: Sampling Ambient Water for
Determination of Trace Metals at EPA Water Quality
Criteria Levels
Section 3- Quality Control Supplement for Determination of Trace
Metals at EPA Water Quality Criteria Levels Using
EPA Metals Methods
Section 4- Guidance on the Documentation and Evaluation of
Trace Metals Data Collected for Clean Water Act
Compliance Monitoring
Appendices
Appendix A- Laboratories
Appendix B- Office of Water Interim Guidance Concerning the
Collection of Metals Data at WQC Levels
(November 8, 1994)
Appendix C- Office of Water Policy and Technical Guidance on
Interpretation and Implementation of Aquatic Life
Metals Criteria (October 1, 1993)
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SECTION 1
Monitoring Trace Metals at Ambient Water Quality
Criteria Levels: Issues, Plans and Schedule
EPA Office of Water, Engineering & Analysis Division
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Monitoring Trace Metals at
Ambient Water Quality Criteria Levels:
Issues, Plans, and Schedule
October 1994
U.S. Environmental Protection Agency
Office of Water
Office of Science and Technology
Engineering and Analysis Division (4303)
401 M St. SW
Washington, DC 20460
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Monitoring Trace Metals at Ambient WQC Levels
SUMMARY
The Clean Water Act requires that ambient water quality criteria (WQC) published by EPA reflect the
latest scientific knowledge concerning the physical fate (e.g., concentration and dispersal) of pollutants,
the effects of pollutants on ecological and human health and welfare, and the effect of pollutants on
biological community diversity, productivity, and stability. Since the inception of its water quality
standards program in 1965, it has been the Agency's position that, because analytical detection limits are
not related to actual environmental impacts, they should not be a consideration when calculating water
quality criteria. This position is consistent with statutory requirements that water quality standards are
to be protective of designated stream uses. Further, it is believed that setting the criteria at levels that
reflect adequate protection forces the improvement of analytical detection methods.1
Current ambient WQC levels for trace metals require measurement capabilities at levels as much as 280
times lower than those achievable using existing EPA methods and required to support technology-based
permits. This document addresses the difficulties associated with measuring trace metals at ambient WQC
levels and outlines a plan and schedule for achieving such measurements.
The difficulties in measuring metals concentrations at WQC levels include: (1) precluding contamination,
(2) a lack of methods for measurement of some trace metals and biologically significant species of these
metals at WQC levels, and (3) a lack of environmental laboratories capable of performing trace metals
measurements on a large-scale, routine basis. The Analytical Methods Staff of the Office of Science and
Technology's (OST) Engineering and Analysis Division (EAD) is engaged in a number of activities to
address these challenges. Specifically, EAD
• Has written a draft sampling method that describes the sample handling and quality
control procedures necessary to assure reliable sampling of trace metals.
• Has supplemented existing EPA methods with the necessary analytical guidance to assure
reliable measurements at WQC levels. The analytical guidance is in the form of a quality
control (QC) supplement to existing EPA methods. A first draft of this QC supplement
has been written by EAD.
• Has established a working committee of recognized trace metals analysis experts to assist
with the development, review, and improvement of sampling and analysis techniques for
determination of trace metals.
• Is developing additional methods needed to allow reliable measurements of those metals
that cannot be measured at WQC levels using the supplemented EPA methods.
• Is developing data review guidance that will allow reviewers to assess the quality of data
gathered using the sampling method, analytical methods, and QC supplement.
EAD plans to validate the sampling method and test the QC supplement and analytical methods in at least
one laboratory capable of making trace-metals measurements.
Routine measurement at WQC levels can be achieved within a short time for those metals and metal
species for which an EPA analytical method is available. (Such methods can be supplemented to include
the rigorous sample handling and quality control procedures that are necessary to deliver verifiable data
at WQC levels.) Development of methods for the remaining metals and developing capabilities for
analysis of those metals in commercial laboratories will require considerable effort and may take more
than a year to achieve. The Water Offices should be aware that not being able to measure certain metals
at WQC levels may preclude enforcement of WQC levels for these metals.
'Water Quality Standards; Establishment of Numeric Criteria for Priority Toxic Pollutants; Suites' Compliance' (also referred to as
The National Toxics Rule'), 40 CFR Part 131, (57 FR 60848, December 22, 1992).
October 1994
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Monitoring Trace Metals at Ambient WQC Levels
BACKGROUND
EPA's increased emphasis on water quality-based permitting has necessitated the determination of metals
and other analytes at levels much lower than those required by technology-based effluent limits and
afforded by routine analyses in environmental laboratories. The first three columns of Table 1 below
compare ambient WQC levels with minimum levels achieved by methods used hi EPA's technology-based
effluent guidelines program and typically employed to determine permit compliance. Also shown are the
method detection limits (MDLs) required to achieve WQC levels and the lowest MDLs in presently
available EPA methods.
Table 1
Lowest EPA Ambient Water Quality Criteria, Required Detection Levels, and Minimum Levels
and Method Detection Limits Achieved by Existing EPA Methods
Metal
Antimony
Arsenic
Cadmium
Chromium (III)
Chromium(VI)
Copper
Lead
Mercury
Nickel
Selenium
Silver
Thallium
Zinc
Minimum
Level
(ug/L)1
20
10
5
—
20
25
5
0.2
40
5
10
10 .
20
Lowest Ambient
Water Quality
Criterion (ug/L)2
14'
0.018s
0.32s
57s
10.5
2.5
0.146
0.012
7.1
5.0
- 0.31*
1.7'
28*
MDL Needed
to Achieve
WQC (ug/L)3
1.4
0.002
0.032
5.7
1.05
0.25
0.014
0.001
0.71
0.5
0.031
0.017
2.8
Lowest EPA
MDL Currently
Available (ug/L)4
0.4
0.5
0.016
—
0.3
0.023
0.074
0.01
0.081
0.6
0.1
0.3
0.3
Minimum level for reliable measurement in methods used in EPA's technology-based effluent guidelines program.
Lowest of the freshwater, marine, and human health WQC promulgated by EPA for 14 states at 40 CFR Part 131 (57
FR 60848), with hardness-dependent freshwater aquatic life criteria adjusted in accordance with 57 FR 60848 to reflect
the worst case hardness of 25 mg/L CaCO, and appropriate aquatic life criteria adjusted in accordance with 10/1/93
Office of Water guidance to reflect dissolved metals criteria.
Required Method Detection Limit (MDL, 40 CFR Part 136, Appendix B), with safety factor of 10 to allow reb'able
measurements at WQC level.
Method Detection Limit (MDL) as listed in existing EPA method.
Criterion reflects recalculated value using IRIS. See 57 FR 60848 and Water Quality Criteria Summary. USEPA, OST,
HECD, 5/1/91.
Hardness dependent criterion.
The determination of many trace metals in environmental samples at WQC levels has been accomplished
in marine science research laboratories. The most serious problem faced by these and other laboratories
that attempt to determine metals at trace concentrations is the potential for sample contamination from
any metal allowed to contact the sample. A recent discovery by the U.S. Geological Survey (USGS) that
some metals data in one of its major databases may be the result of sample contamination and similar
findings in EPA's New York/New Jersey Harbor studies suggest the need for EPA to take steps to ensure
October 1994
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Monitoring Trace Metals at Ambient WQC Levels
that similar results are not produced as EPA continues to make measurements at WQC levels.24
In general, in order to achieve accurate and precise measurement of a particular concentration, both the
detection limit and the blank results should be less than one-tenth of that concentration. The fourth
colunyi in Table 1 above lists the MDLs required for determination of trace metals at WQC levels.
These values reflect MDLs that are 10 times lower than the WQC level to ensure that trace contamination
will be detected and that the potential reporting of false positives will be minimized.
The required MDLs shown in the fourth column can be compared with the lowest MDLs currently
available in EPA methods, shown in the last column of Table 1. For arsenic, the level by which the
existing MDL must be lowered to make reliable measurements at the WQC level is a factor of
approximately 280; for mercury the factor is approximately 10; and for lead the factor is approximately
5. Improvements in any measurement system by these factors is not straightforward, and considerable
resources will be required to attain these levels.
Potential for False Positives Resulting From Contamination
Because trace metals are ubiquitous in the environment, the precautions necessary to preclude
contamination are more extensive than those required to preclude contamination when synthetic organic
compounds and other non-ubiquitous substances are determined. These difficulties and the recent USGS
findings strongly suggest that EPA should implement measures to avoid the possibility of producing
results that may later be shown to be the result of contamination.
Assessment of U.S. Laboratory Capability
Over the past year, EAD staff have contacted the foremost researchers in the field of trace metals
measurements and have visited the laboratories of several of these researchers. The main conclusion
drawn from these contacts and visits is that the measurement of trace metals at WQC levels is a much
more formidable problem than initially believed. At present, EAD is not aware of a single laboratory
that is capable of reliably determining all of the metals at the required WQC levels for which ambient
criteria have been published, and there are very few laboratories that are capable of reliably determining
even a subset of the metals at these levels. It is believed that this lack of existing analytical capability
will necessitate laboratory improvements that will,take months to years to accomplish.
Contamination of Dissolved Trace Element Data: Present Understanding. Ramifications, and Issues that Require
Resolution, Office of Water Quality Technical Memorandum 91.10; U.S. Geological Survey, Reston, VA Sept. 30,
1991.
Evaluation of Trace-Metal Levels in Ambient Waters and Tributaries to New York/New Jersey Harbor for Waste Load
Allocation; Environmental Protection Agency, Office of Wetlands, Oceans, and Watersheds and Region II, Jan. 9,
1992. (Prepared by Battelle Ocean Sciences, 397 Washington Street, Duxbury. MA 02332).
October 1994
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Monitoring Trace Metals at Ambient WQC Levels
METAL FORMS AND SPECIATION
The bioavailability of a metal in natural waters depends on the chemical form in which it exists. Metals
can ocfiur in organic and inorganic forms. The organic form of a given metal can exist as one or more
organo-metallic compounds; the inorganic form can exist in one or more oxidation states. Sample
preparation and analysis procedures, and the equipment required for each, can differ considerably for
measurement of the various forms. Therefore, determination of more than one form of a given metal
may require multiple sample handling procedures, sample preservation techniques, sample preparation
procedures, and analytical methods. These differences are summarized below.
Total, Total Recoverable, and Dissolved Forms
Determination of "total metals" is directed at all forms of the metal in a sample including dissolved metals
and the metals in all particulates. Total metals are determined by vigorous digestion of the sample with
a hot, strong acid or acids to dissolve all forms of the metal.
Determination of "total recoverable metals" is directed at metals weakly bound to particle surfaces plus
dissolved metals. Total recoverable metals are determined by digestion with hot, dilute mineral acid(s)
to remove the weakly bound metals without dissolving the particles to which they are bound.
Determination of "dissolved metals" is directed at only those particles, molecules, and elementary forms
of the metal that are able to pass through a 0.45 micron filter. Dissolved metals are determined by
filtering the sample and acidifying it to preserve the metals. Current Office of Water (OW) guidance
recommends the use of dissolved metals to set and measure compliance with water quality standards
because the dissolved metal more closely approximates the bioavailable fraction of metal in the water than
does the total recoverable form.4 Current OW guidance also provides recommendations concerning
conversion factors that should be used to calculate EPA. dissolved metals criteria from the published total
recoverable metals criteria. All dissolved metals criteria printed and discussed in this document are
calculated in accordance with the current OW guidance.
Oxidation States
Dissolved metals can occur in natural waters in several oxidation states,, some of which are more toxic
than others. For example, chromium occurs in the hexavalent (Cr*6) and trivalent (Cr+3) forms, of which
the hexavalent form is considerably more toxic to aquatic life than the trivalent form. Similarly, the
inorganic forms of arsenic include arsenate (As*5) and arsenite (As*3). Implementation of water quality
criteria for multiple oxidation states of a particular metal may necessitate the use of different sample
handling procedures, different holding times, and different analytical methods for monitoring purposes.
Organo-metallic Species
The bioaccumulation potential of methylmercury in organisms is in the range of 106 - 108; therefore,
determinations of methylmercury may be of greater concern than determinations of mercury. Similarly,
organo-arsenicals may be of greater environmental concern than the inorganic forms. Further, within
a group of organo-metallics, each individual compound may have different toxic effects. If water quality
criteria are developed for organo-metallic species, it will be necessary utilize sample preparation and
Prothro, M., Acting Assistant Administrator for Water, Memorandum to Water Management Division Directors and
Environmental Services Division Directors, Oct. 1, 1993.
October 1994
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Monitoring Trace Metals at Ambient WQC Levels
analytical procedures that differ from those used in determination of the inorganic forms (although the
organo-metallics can usually be measured as a group or individually with the same procedure).
October 1994
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Monitoring Trace Metals at Ambient WQC Levels
IMPLEMENTATION OF TRACE METALS ANALYSES IN EPA PROGRAMS
USGS Plans
The USGS has embarked on a program to lower the levels at which trace measurements will be made.
This program will occur in two phases. USGS' Phase I effort is directed at making reliable
measurements at the one part-per-billion (ppb; ug/L) level. To achieve this level, USGS believes that
significant improvement must occur in sample collection. USGS has specified sampling equipment, has
developed a sampling manual, and has had its program operational at the one ppb level since November
1993. USGS does not have the need to regulate discharges, and all analyses conducted by USGS will
be at its Water Quality Laboratory near Denver. Therefore, USGS does not have the need to develop
detailed, written methods and monitor multiple facilities that are making trace metals measurements. In
contrast, EPA will need to develop detailed methods, sampling guidance, and data review criteria to
support Federal and State regulatory programs.
In order to make reliable measurements at the one ppb level, USGS has attained detection limits on the
order of 0.1 ppb. Based on information provided by USGS, HAD .estimates that achieving the one ppb
level in commercial and state laboratories will cost approximately $5,000 in fixed costs for individual
laboratory modifications. Per sample,costs are expected to increase by $50 - 100 because of the
additional bottle preparation and care in sampling required.
In Phase II, USGS will move to reliable measurements at the 0.1 ppb level. Achieving this level will
require detection limits on the order of 0.01 ppb and is estimated to take one year since it will require
extensive modification of field sampling and laboratory equipment and protocols. USGS has begun work
on a self-designed Class-100 clean room and will equip this room with Class-100 clean benches. The
Class-100 facility will be used for sample and sample bottle preparation. To preclude contamination and
fix responsibility for metals analysis at the 0.1 ppb level, USGS is considering teams of personnel who
will carry out all aspects of the metals determinations, from bottle cleaning through sampling through
sample preparation through the analysis. Although this system is inefficient because a small group of
highly trained people must perform even the most menial tasks, the system vests responsibility in people
who know most about the potential pitfalls associated with trace metals determinations.
Based on information provided by USGS and other laboratories, HAD estimates that achieving the 0.1
ppb Phase II level will require the typical commercial or state laboratory to invest approximately
$325,000 in fixed costs for laboratory modifications and equipment, primarily for a clean room, clean
benches, inductively coupled plasma mass spectrometer (ICP/MS) with hydride attachment, mercury
analyzer, and stabilized temperature platform graphite furnace atomic absorption spectrophotometer
(STGFAA).
Bevond USGS Levels
The above section describes USGS' Phase I and Phase II plans for measurement of trace metals at the
1 and 0.1 ppb level. As noted in that section, achievement of the Phase II 0.1 ppb level is estimated by
USGS to take more than one year, and is estimated by HAD to require more than $325,000 in
implementation costs for state and commercial laboratories. However, achievement of the Phase II levels
by USGS will be inadequate for EPA purposes because EPA and State ambient water quality criteria for
some metals are more than ten times lower than the USGS Phase II levels. Therefore, EPA efforts to
achieve WQC levels must necessarily be more extensive than USGS' efforts. Further, because the
potential for contamination at these lower levels is great, the Agency must be certain that data collected
at these levels are reliable.
October 1994
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Monitoring Trace Metals at Ambient WQC Levels
Based on information provided by USGS and other laboratories, BAD estimates that achieving WQC
levels may cost upwards of $500,000 in fixed costs for setup and operation of a single laboratory,
including all equipment. These costs are driven by the same equipment costs as in the USGS Phase II
costs, but are increased by analyzers for various species of mercury and other metals, and by the
additional cleanliness requirements for measurement of these elements at high part-per-quadrillion levels.
Per sample costs may increase by $100 - 200, but can be expected to drop as laboratories become skilled
at handling samples.
Projected EPA Activities
Guidance concerning the implementation of aquatic life metals criteria was issued on 10/1/93.3 As part
of the Office of Science and Technology's efforts to achieve the measurement of trace metals at these and
other ambient WQC levels, three guidance development efforts are currently being directed by William
A. Telliard of the Engineering and Analysis Division. These efforts are focused on the development of
sampling, analytical, and data review guidance. To expedite these efforts, HAD has established a
working committee of recognized trace metals analysis experts to assist with development and
improvement of sampling and analysis techniques. The first meeting of this committee was held on
November 12, 1993. BAD has retained certain members of this committee to review and validate the
sampling guidance and the analytical guidance/methods. Specific activities related to .the development
of these guidance materials are described below.
Sampling Guidance
For sampling guidance, BAD originally intended to avoid duplication of effort by using portions of the
USGS manual that are applicable to EPA programs. However, after reviewing the USGS sampling
manual, it was determined that the manual is so specific to USGS' programs that a separate EPA
sampling manual is needed. To meet this need, BAD completed a draft Method for Sampling Ambient
Water for Determination of Metals at EPA Ambient Water Quality Criteria Levels in January 1994.
Following limited peer review, the draft was revised in October .1994, and is currently undergoing more
extensive peer review within the Agency. Final revision of this sampling guidance, which includes clean
techniques recommended by USGS and others, is planned for December 1994. In addition, BAD is
planning to issue a similar guidance document that has been adapted to reflect effluent sampling
requirements. The draft guidance for effluent sampling is scheduled for completion in January 1995.
Validation of these procedures is planned for early 1995.
Analytical Methods
EPA's Environmental Monitoring Systems Laboratory in Cincinnati, Ohio (EMSL-Ci) has developed
methods for the determination of several toxic (priority pollutant) metals at ambient WQC levels. These
methods and their corresponding detection levels are shown below in Table 2 along with the lowest
applicable WQC. Because these methods lack the rigorous sample handling and quality control
procedures that are necessary to deliver verifiable data at the WQC levels, BAD has written a QC
supplement to these methods. This draft Quality Control Supplement for Determination of Metals at
Ambient Water Quality Criteria Levels Vsing EPA Metals Methods supplements EPA methods 200.7,
200.8, 200.9, 200.10, 200.13, and 218.6, and provides the procedures necessary to reliably measure
antimony, cadmium, hexavalent chromium, copper, nickel, and zinc at the water quality criteria level.
5 Prolhro, M., Acting Assistant Administrator for Water, Memorandum to Water Management Division Directors and
Environmental Services Division Directors; Oct. 1, 1993.
8 October 1994
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Table 2
Lowest EPA Water Quality Criteria for Toxic Metals and Species; Existing EPA Methods that Achieve or
Come Closest to Achieving these Criteria; and Analytical Techniques, Minimum Levels, and Method
Detection Limits for these EPA Methods
r
Metal
Antimony
Arsenic
fjiHtriimn
Chromium (HI)
Chromium (VI)
Copper
Lead
Mercury
Nickel
Selenium
Silver
Thallium
Zinc
Lowest
Ambient
Water Quality
Criterion
(ug/L)'
14
0.018
0.32
57
10.5
2.5
0.14
0.012
7.1
5
0.31
1.7
28
EPA method, analytical technique, and MDL/ML
in ug/L
Method
number
200.8
200.9
200.9
200.13
—
218.6
200.10
200.10
245.7
200.8
200.9
200.10
200.9
200.8 ,
200.8
200.7
200.8
200.9
Analytical
technique
ICP/MS
STGFAA
STGFAA
CC/STGFAA
—
Ion Chrom. .
CC/ICP/MS
CC/ICP/MS
CVAF
ICP/MS
STGFAA
CC/ICP/MS
STGFAA
ICP/MS
ICP/MS
ICP/AES
ICP/MS
STGFAA
MDL2
0.4
0.8
0.5
0.016
0.3
0.023
0.074
0.01
0.5
0.6
0.081
0.6
0.1
0.3
2
1.8
0.3
MLJ
1
2
2
0.05
1
0.05
0.2
0.02
2
2
0.2
2
0.2
1
5
5
1
WQC
level
achieved4
Yes
Yes
No
Yes
No
Yes
Yes
No
No
Yes
Yes
Yes
No
No
No
Yes
Yes
Yes
Key:
Notes:
1.
2.
3.
4.
ICP = Inductively coupled plasma Ion chrom
AES = Atomic emission spectrometry CC
MS = Mass spectrometry . CVAF
CFAA = Graphite furnace atomic absorption spectrometry STGFAA
Ion chromatography
dictation/concentration
Cold vapor atomic fluorescence
Stabilized temperature GFAA
Lowest of the freshwater, marine, and human health WQC promulgated by EPA for 14 states at 40 CFR Part 131 (57 FR 60848),
with hardness-dependent freshwater aquatic life criteria adjusted in accordance with 57 FR 60848 to reflect the worst case hardness
of 25 mg/L CaCO, and all aquatic life criteria adjusted in accordance with the 10/1 /93 Office of Water guidance to reflect dissolved
metals criteria. A complete listing of all WQC, including total, dissolved, and levels calculated with a hardness of 25 mg/L CaCO,
and a hardness of 100 mg/L CaCO, is provided in Appendix A.
Method Detection Limit (40 CFR Part 136, Appendix B) as listed in existing EPA method.
Minimum Level (ML) calculated by multiplying the existing EPA MDL by 3.18 and rounding result to the nearest multiple of 1, 2,
5, 10, 20, 50, etc in accordance with procedures utilized by EAD and described in the EPA Draft National Guidance for the
Permitting, Monitoring, and Enforcement of Water Quality-Based Effluent Limitations Set Below Analytical Detection/QuantitoMon
Levels, March 22, 1994.
Determination of the metal is achieved if MDL is less than one-tenth the WQC level.
October 1994
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Monitoring Trace Metals at Ambient WQC Levels
EAD believes that the supplemented methods may also yield reliable measurements of lead, selenium,
silver, and thallium at water quality criteria levels. Single laboratory testing of this QC Supplement is
underway; revision of the QC Supplement to reflect the results of the single laboratory validation is
scheduled for completion in December 1994. New EPA methods that consolidate the validated techniques
described in the existing methods and the QC Supplement are scheduled for release in March 1995.
Additional method development efforts are required for the measurement of arsenic, trivalent chromium,
and mercury at WQC levels. EMSL-Ci has recently developed a method for determination of mercury,
but this method does not achieve the detection level needed to make reliable measurements.at the WQC
level. A draft EAD method for determination of mercury at WQC levels has recently been completed
and is undergoing internal review. EAD has also identified and is evaluating techniques for the analysis
of arsenic and trivalent chromium at water quality criteria levels. EAD intends to utilize the results of
the current studies to prepare draft methods for these analytes.
The QC Supplement and any method(s) developed by EAD will undergo single laboratory testing in
marine research laboratories presently making trace metals determinations. These laboratories will be
used because the routine laboratories employed by EPA do not have the facilities and familiarity with the
ultra-clean techniques necessary to make these determinations reliably.
Finally, EAD has gathered information regarding EPA methods and other analytical techniques that may
be useful in measuring metal forms and species for which no WQC exist, but which were identified by
EAD's trace metals committee to be of regulatory concern at the local level. These forms and species,
which are shown in Table 3, are: total chromium, free copper, methylmercury, molybdenum, total tin,
and organotin.6 .
TableS
Existing EPA Methods and Techniques Providing the Lowest Minimum Levels
and Method Detection Limits for Additional Metals
Identified to be of Potential Concern by the EAD Workgroup
Metal
Chromium
Copper (free)
Mercury (methyl)
Molybdenum
Tin
Tin (organo)
EPA method, analytical technique, and
MDL/MLinug/L
Method
number
200.8
200.9
—
—
200.8
200.9
—
Analytical
technique
ICP/MS
STGFAA
—
—
ICP/MS
STGFAA
—
MDL
0.9
0.1
0.3
1.7
ML
2
0.2
1
5
Key:
ICP/MS
STGFAA
= Inductively Coupled Plasma/Mass spectrometry
= Stabilized temperature graphite furnace atomic absorption spectrometry
Beryllium and arsenic (III) were also discussed by the BAD trace metals workgroup because water quality criteria for
these metals were previously published by EPA, but subsequently withdrawn. The techniques identified by the
members of the EAD trace metals workgroup as most closely achieving the previously published WQC levels are
shown in Appendix B of this document for informational purposes.
10
October 1994
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Monitoring Trace Metals at Ambient WQC Levels
If water quality criteria are developed for these metals forms and species, EAD is prepared to supplement
existing methods and develop new methods as needed to make reliable measurements at the WQC levels.
Appendix B provides a complete summary of the method development efforts required for each metal of
interest. For each metal .form and species, Appendix B details the lowest ambient WQC, analytical
techniques and available EPA methods that are or may be capable of allowing measurements at that level,
and the estimated detection limit for that technique. (In some cases, it is generally thought that new
generation instruments and techniques such as multiple injections may reduce method detection limits for
the EPA methods cited in Tables 2 and 3 to levels lower than the currently specified value. In such
cases, the lower method detection limit is cited in Appendix B and is suffixed with "est.".) Because
analysis of briny samples may be required of permittees discharging into harbor areas, Appendix B also
provides information regarding additional sample preparation procedures that may be required to analyze
brackish samples.
Data Review
Some reported trace metals concentrations in existing EPA databases may be the result of contamination.
EAD has been asked to develop data review protocols for examination of these data to make a
determination that the data are, or are not, of sufficient quality for EPA purposes. It is EAD's
understanding that these data are not accompanied by quality control (QC) data, particularly data for
blanks that would prove that the positive results are not the result of contamination. In the absence of
data for blanks and other QC analyses, little can be done to determine if these data are reliable, and the
writing of data review protocols and extensive review of the data will not improve data quality. In
addition, it is EAD's understanding that the analytical methods used for data gathering may not have
included quality control criteria that would result in verifiable data. It is EAD's experience that analytical
methods and data review are linked in that data collected using methods that include rigorous quality
control criteria can be validated, whereas data collected using methods that lack these criteria cannot.
During FY95, EAD will develop functional guidelines for review of metals data generated in accordance
with the analytical methods developed by EMSL-Ci and EAD. These guidelines will allow the quality
of the data to be defined prior to its entry into EPA databases and will provide a trail from the data back
to its source.
Schedule
The schedule in Table 4 below details EAD's projected efforts to develop guidance for determination of
metals at WQC levels.
October 1994 , 11
1 /?
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Monitoring Trace Metals at Ambient WQC Levels
Table 4
Schedule of Plans
• . Sampling
Activity
Hold Committee Meeting
Write Draft Sampling Method
Release Sampling Method for Peer Review
Release Sampling Method for Agency Review
Revise Sampling Method Based on Agency Review
Release Revised Sampling Method for Further Review
Release Final Sampling Method
Release Draft Effluent Sampling Guidance for Review
Analytics
Activity
Hold Committee Meeting
Write QC Supplement to EPA Methods
Release QC Supplement for Peer Review
Release QC Supplement for Agency Review
Issue Draft QC Supplement
Test QC Supplement
Release Final QC Supplement
Release Consolidated Methods
Data Review
Activity
Write Data Package Requirements for QC Supplement
Write Draft of Data Review Guidance
Revise Guidance Based on Tests
Issue Final Guidance
Guidance
Scheduled Completion Date
12 Nov. 1993
21 Jan. 1994
26 Jan. 1994
18 April 1994
12 Oct. 1994
20 Oct. 1994
31 Dec. 1994
31 Jan. 1995
1 Method
Scheduled Completion Date
12 Nov. 1993
01 Jan. 1994
26 Jan. 1994
18 April 1994
01 June 1994
15 Nov. 1994
31 Dec. 1994
31 Mar. 1995
/ Guidelines ' ,
Scheduled Completion Date
30 Sept. 1994
31 Mar. 1995
30 June 1995
30 Aug. 1995
An estimated $50,000 will be needed to perform single laboratory testing of EAD's sampling method and
QC supplement in marine research laboratories already equipped with the instrumentation and facilities
necessary to achieve the required detection levels. Additional costs will be incurred if subsequent testing
efforts are performed in commercial environmental laboratories typically contracted by EPA.
12
October 1994
-------
Appendix A
EPA Ambient Water Quality Criteria for Total Recoverable and Total Dissolved Priority
Pollutant Metals and Metal Species Calculated at a Hardness of 100 mg/L and 25 mg/L CaCO3
-------
EPA Ambient Water Quality Criteria for Total Recoverable and Total Dissolved Priority Pollutant Metab and Metal Species
Calculated at a Hardness of 100 mg/L and 25 mg/L CaCO,
McUl
Sb
As
Cd">
Cr (IIDm
Cr(VD
Cum
Pbm
Hi
Nim
Se
Agm
Tl
Zn">
Ambient Water Quality Criteria11'
0.31
—
31
Chronic0'
Tot. Rec.
lOOrag/L
c»co,
—
190
I.I
210
11
12
3.2
0.012
160
5
—
—
110
Chronic141
Tot. .Diss.
100 mg/L
CXX>,
—
181
0.94
179
10.5
10.2
0.8
136
»>
—
...
94
Chronic0*
Tot. Rec.
25 mg/L
CaCO,
._
190
0.38
67
11
3.6
0.54
0.011
49
5
—
...
33
Chronic'4'-0'
Tot. Disi.
25 mg/L
c«co,
—
181
0.32
57
10.5
3.1
0.14
m
42
m
-
_.
28
Marine Criteria
Acute01
Tot. Rec.
~
69
43
...
1100
2.9
220
2.1
75
300
2.3
...
95
Acute(4>
Tot. Diss.
—
65.6
36.6
—
1050
2.5
110
1.8
64
a>
2.0
—
81
Chronic"'
Tot. Rec.
—
36
9.3
—
50
2.9
8.5
0.025
8.3
71
—
—
86
Chronic14'
Tot. Disi.
—
34.2
7.9
_.
47.5
2.5
2.1
m
7.1
(S)
—
—
73
Human Hethh Criteria
H,0/organism0>
Tot. Rec.
. M">
0.0W>
—
—
—
—
~
0.14
610*
— '
_
/.7">
—
organism*4
Tot. Rec.
4300"
0.14«
_
—
—
—
—
0.15
4600">
— .
—
6.3">
—
EPA
Method
200.8
200.9
200.13
—
218.6
200.10
200.10
245.7
200.10
200.9
200.8
200.8
200.9
Lowest
MDL
(«/U
0.4
0.5
0.016
— .
0.3
0.023
0.074
0.01
0.081
0.6
0.1
0.3
0.3
MDL
Needed
WL)"
1.4
0.0018
0.032
5.7
l.OS
0.25
0.014
0.0012
0.71
0.5
0.031
0.17
2.8
WQC
Mctr*
Yet
No
Yet
No
Yea
Yea
No
•MMHMlilH
No
Yea
No
No
No
Yea
(1) WQC promulgated in the National Toxict Rule (NTR) for 14 states at 40 CFK Part 131 (57 FR 60848). Critria for metals, listed at 40 CFK Part 131 arc expressed a> total recoverable at a hardness of 100 mg/L CaCO, and a water
effect ratio (WER) of 1.0. The lowest WQC for each analytc is shaded.
(2) The MDL needed to achieve determination at the WQC levels is one-tenth of the lowest WQC. The WQC level is considered met if the MDL is less than or equal to one-tenth of the lowest WQC.
(3) As listed in the NTR at 40 CFK Part 131 for total recoverable metals. Hardness dependent freshwater acute and chronic criteria expressed at a hardness of 100 mg/L CaCO, and a WER of 1.0.
(4) For Cd, Cr Gil). Cu. Ni. and Zn, acute and chronic criteria for dissolved metals and metal species were calculated by taking 85% of the corresponding uxal recoverable criteria level. For Aa and Cr (VO. acute and chronic crteria
for dissolved metals and metal species were calculated by taking 95 % of the corresponding total recoverable criteria level. For lead, acute dissolved criteria were calculated by taking 50% of the corresponding lota] recoverable fcwl;
for lead chronic criteria, dissolved criteria were calculated by taking 25% of the total recoverable levels. Dissolved values for mercury chronic criteria and selenium acute and chronic criteria were not calculated because these metals
bkMCCumulate, and dissolved criteria would not be appropriate. (Guidance Document on Dissolved Criteria: Expression of Aquatic Life Criteria, October 1993. Attachment 2 to memorandum from Martha Prothro to Water Management
Division Directors, October 1, 1993.)
(5) Hardness dependent freshwater acute and chronic criteria recalculated at a hardness of 25 mg/L CaCO, and a WER of 1.0 as specified at 40 CFR Part 131.36 (b)(2). For dissolved metals, hardness calculations were performed prior
. to adjusting for dissolved levels.»
(6) Criterion reflects recalculated value using IRIS.
(7) Freshwater criteria are hardness dependent for this metal.
(8) Metal is bic«ccumuUtivc and, therefore, it is not appropriate lo calculate WQC for dissolved levels. (Guidance Document on Dissolved Criteria: Expression of Aquatic Life Criteria. October 1993. Attachment 2 to memorandum
from Martha Prothro lo Water Management Division Directors, October I, 1993.)
-------
Appendix B
Analytical Methods for Trace Metals Determinations
2 r
-------
Appendix B
Analytical Methods and Technologies for Trace Metals Determinations
ANTIMONY (Sb)
Lowest WQC Level Required: 14 ug/L
Species: Total only
Analytical Techniques Capable of Achieving WQC Level:
Technique
ICP/MS
HYDAA
STGFAA
Detection EPA
limit (ug/L) method Note
0.04 est. 200.8
0.1 est. none
0.8 200.9
Extraction/Concentration Techniques Required for Seawater: None if hydride generation is used
ARSENIC (As)
Lowest WQC Level Required: 0.018 ug/L (for Total Arsenic)
Species: Total
Analytical Techniques Capable of Achieving WQC Level: None
Techniques Capable of Achieving Lowest Detection Levels:
Total arsenic:
Technique
Detection EPA
limit (ug/L) method Note
HYD/ICP/MS
HYDAA
0.003 est. none 1 L sample req'd
0.1 est. none
Arsenic (III)*:
Technique
pH~4/Cryo distill/HYDAA
Detection
limit (ug/L)
0.001 est.
EPA
method
none
Note
Extraction/Concentration Techniques Required for Seawater: None if hydride generation is used
*EPA has replaced aquatic life criteria for arsenic(III) with aquatic life criteria for total arsenic. Potential techniques for
analysis of arsenic (III) are presented above because they were discussed by the HAD trace metals workgroup with the thought
that analysis of total arsenic and of arsenic (III) may be useful in determining the need to measure organoarsehic (which is
naturally produced by phytoplankton) in certain local environments. In addition, EPA's decision to base WQC for arsenic on
the total recoverable form was based in part on the lack of practical analytical methods to measure trivalent As (see response to
comments published in 57 FR 60848, 12/22/92).
-------
Appendix B
Analytical Methods and Technologies for Trace Metals Determinations
(continued)
BERYLLIUM (Be)
WQC Level Required: None*
Species: Total
Techniques Capable of Achieving Lowest Detection Levels:
Detection EPA
Technique limit fug/L) method Note
ICP/MS , 0.05 est. 200.8
Mult. inj./STGFAA 0.01 est. 200.9
Complex. /extr/fluor/
GC/Sel. detector 0.002 none
Extraction/Concentration Techniques Required for Seawater:
Complex./extr./fluor/GC/Sel. detector
"EPA has withdrawn the water quality criteria for beryllium. The information provided above was discussed by the EAO trace
metals workgroup because of its earlier concern to EPA.
CADMIUM (Cd)
Lowest WQC Level Required: 0.32 ug/L
Species: Total
Analytical Techniques Capable of Achieving WQC Level:
Detection EPA
Technique limit (ug/L) method Note
CC/STGFAA 0.016 200.13
Extraction/Concentration Techniques Required for Seawater:
Complex with APDC or DDDC/extr./then as above
EPA methods 200.12 and 200.13
-------
Appendix B
Analytical Methods and Technologies for Trace Metals Determinations
(continued)
CHROMIUM (Cr)
Lowest WQC Level Required: Chromium (VI): 10.5 ug/L
Chromium (III): 57 ug/L
Species: Total Chromium, Chromium (VI), and Chromium (III)
Analytical Techniques Capable of Achieving WQC Level:
Chromium (VI):
Detection EPA
Technique limit (ug/L) method Note
Ion chrom/Deriv/Color. 0.3 218.6 No metal parts!
APDC/MIBK/STGFAA 0.1 none May be unreliable
Techniques Capable of Achieving Lowest Detection Levels
Chromium (III):
Detection EPA
Technique . limit (ug/L) method Note
None Identified
Total chromium*:
Detection EPA
Technique , limit (ug/L) method Note
ICP/MS O.lest. 200.8
STGFAA 0.1 200.9
Extraction/Concentration Techniques Required for Seawater: None in addition to above
/
"EPA water quality criteria do not exist for total chromium. Potential techniques for analysis of total chromium are presented
above because they were discussed by the HAD trace metals workgroup.
19
-------
Appendix B
Analytical Methods and Technologies for Trace Metals Determinations
(continued)
COPPER (Cu)
*
Lowest WQC Level Required: 2.5 ug/L (for Total Copper)
Species: Total and "Free" (thought to be Cu2*)
Analytical Techniques Capable of Achieving WQC Level:
Total copper:
Detection EPA
Technique limit (ug/L) method Note
JCP/MS 0.1 est. 200.8
Mult. inj. STGFAA 0.1 est. 200.9
CC/ICP/MS 0.023 200.10
Techniques Capable of Achieving Lowest Detection Levels:
Free copper*:
Detection
Technique limit (ug/L) method Note
Ligand/titr./STGFAA 0.1 est. none One sample per day
Extraction/Concentration Techniques Required for Seawater:
Total: APDC/DDDC chelation/MIBK extraction/STGFAA
Free: None in addition to above
*EPA water quality criteria do not exist for free copper. Potential techniques for analysis of free copper are presented above
because they were discussed by the EAD trace metals workgroup with the knowledge that investigation of site-specific criteria
for free copper is. underway in some localities.
LEAD (Pb)
Lowest WQC Level Required: 0.14 ug/L
Species: Total
Analytical Techniques Capable of Achieving WQC Level: None
Techniques Capable of Achieving Lowest Detecton Levels:
Detection EPA
Technique limit fug/L) method Note
ICP/MS 0.1 est. 200.8
Mult. inj. STGFAA 0.2 est 200.9
CC/ICP/MS 0.074 200.10
Extraction/Concentration Techniques Required for Seawater: Complex with APDC or
DDDC/extr./then as above EPA methods 200.12 and 200.13
-------
Appendix B
Analytical Methods and Technologies for Trace Metals Determinations
(continued)
MERCURY (Hg)
Lowest WQC Level Required: 0.012 ug/L (Total Mercury)
Species: Total and Methyl
Analytical Techniques Capable of Achieving WQC Level: None
Techniques Capable of Achieving Lowest Detection Levels:
Total mercury: ^
Detection EPA
Technique limit (ug/L) method Note
Reduce/P&T/At.Fl. 0.001 est. none
CVAF 0.01 245.7
Methyl mercury*:
Detection EPA
Technique limit (ug/L) method Note
Distill./ethylation/
P&T/GC/pyrolysis/At.
Fl. 0.0001 none Nick Bloom
Extraction/Concentration Techniques Required for Seawater: None in addition to above
"EPA water quality criteria do not exist for methylmercury. Potential techniques for analysis of mcthylmcrcury are presented
above because they were discussed by the EAD trace metals workgroup due to its well-known bioaccumulation potential and
significance in the environment.
MOLYBDENUM (Mo)
WQC Level Required: None"
Species: Total
Analytical Techniques Capable of Achieving Lowest Detection Level:
Detection EPA
Technique limit (ug/L) method Note
ICP/MS 0.05 est. 200.8
Mult. inj. STGFAA 0.1 est. 200.9
Extraction/Concentration Techniques Required for Seawater: None; ICP/MS detection limit = 0.5
ug/L .
"EPA water quality criteria do not exist for molybdenum. Potential techniques for analysis of molybdenum are presented above
because they were discussed by the EAD trace metals workgroup.
-------
Appendix B
Analytical Methods and Technologies for Trace Metals Determinations
(continued)
NICKEL (Ni)
Lowest WQC Level Required: 7.1 ug/L
Species: Total
Analytical Techniques Capable of Achieving Water Quality Criteria Level:
Detection EPA
Technique limit (ug/L) method Note
ICP/MS 0.5 200.8
STGFAA 0.6 200.9
CC/ICP/MS 0.081 200.10
Extraction/Concentration Techniques Required for Seawater:
SELENIUM (Se)
Lowest WQC Level Required: 5.0 ug/L
Species: Total
Analytical Techniques Capable of Achieving WQC Level: None
Techniques Capable of Achieving Lowest Detection Levels:
Detection EPA
Technique limit (ug/L) method Note
HYD/ICP/MS 0.05 est. none
HYD/STGFAA 0.02 none
Mult. inj. STGFAA 0.5 est. 200.9 Fresh water only
Extraction/Concentration Techniques Required for Seawater: None if hydride generation is used
-------
Appendix B
Analytical Methods and Technologies for Trace Metals Determinations
(continued)
SILVER (Ag)
Lowest WQC Level Required: 0.31 ug/L
Species: Total
Analytical Techniques Capable of Achieving WQC Level: None
Techniques Capable of Achieving Lowest Detection Levels:
Detection EPA
Technique limit (ug/L) method Note
ICP/MS 0.02 est. 200.8
APDC/STGFAA 0.02 none pH sensitive
Extraction/Concentration Techniques Required for Seawater: None with APDC chelation/extraction
THALLIUM (Tl)
Lowest WQC Level Required: 1.7 ug/L
Species: Total
Analytical Techniques Capable of Achieving WQC Level: None
Techniques Capable of Achieving Lowest Detection Levels:
Detection EPA
Technique limit (ug/L) method Note
ICP/MS 0.05 est. 200.8
STGFAA 0.5 est. 200.9
Extraction/Concentration Techniques Required for Seawater: None required with ICP/MS at
projected WQC levels
-------
Appendix B
Analytical Methods and Technologies for Trace Metals Determinations
(continued)
TIN(Sn)
WQC Level Required:
Total: None*
Organo: None*
Species: Total and Organo
Analytical Techniques Capable of Lowest Detection Levels:
Total tin:
Detection EPA
Technique limit (ug/L) method Note
ICP/MS 0.1 est. none
STGFAA 1.7 200.9
Organo-tin:
Detection EPA
Technique limit (ug/L) method Note
Tropolone/ext./GC/FPD : 0.05 est. none Also atomic
emiss. detector
Extraction/Concentration Techniques Required for Seawater: Unknown if required for .total tin
because WQC is not known; none in addition to above for organo-tin
*EPA water quality criteria do not exist for tin and organo-tin. Potential techniques for analysis of tin and organo-tin are
presented above because they were discussed by the HAD trace metals workgroup.
ZINC (Zn) ' '
Lowest WQC Level" Required: 86 ug/L
Species: Total
Analytical Techniques Capable of Achieving WQC Level:
Detection EPA
Technique limit (ug/L) method Note
ICP 2 200.7
ICP/MS 1.8 200.8
STGFAA 0.3 200.9
Extraction/Concentration Techniques Required for Seawater: APDC/DDDC/MIBK extraction/FLAA;
contamination serious problem
-------
SECTION 2
Method 1669: Sampling Ambient Water for
Determination of Trace Metals at
EPA Water Quality Criteria Levels
EPA Office of Water, Engineering & Analysis Division
-------
Method 1669
Sampling Ambient Water for Determination of Trace Metals
at EPA Water Quality Criteria Levels
December 1994
U.S. Environmental Protection Agency
Office of Water
Office of Science and Technology
Engineering and Analysis Division (4303)
401 M St. SW
Washington, DC 20460
.7?
-------
Method 1669
Acknowledgements
This sampling method was prepared under the direction of William A. Telliard of the Engineering
and Analysis Division (HAD) within the U.S. Environmental Agency's (EPA's) Office of Science and
Technology (OST). This-sampling method was prepared under EPA Contract 68-C3-0337 by
DynCorp Environmental, with the assistance of Interface, Inc.
The following researchers in marine chemistry contributed to the philosophy behind this sampling
method. Their contribution is gratefully acknowledged:
Shier Berman, National Research Council, Ottawa, Ontario, Canada;
Nicholas Bloom, Frontier Geosciences Inc, Seattle, Washington;
Eric Crecelius, Battelle Marine Sciences Laboratory, Sequim, Washington;
Russell Flegal, University of California/Santa Cruz, California;
Gary Gill, Texas A & M University at Galveston, Texas;
Carlton Hunt and Dion Lewis, Battelle Ocean Sciences, Duxbury, Massachusetts;
Carl Watras, Wisconsin Department of Natural Resources, Boulder Junction, Wisconsin
Additional support was provided by Ted Martin of the EPA Office of Research and Development's
Environmental Monitoring Systems Laboratory in Cincinnati, Ohio.
This version of the method was prepared after .observations of sampling teams from the University of
California at Santa Cruz, the Wisconsin Department of Natural Resources, the U.S. Geological
Survey, and Battelle Ocean Sciences. The assistance of personnel demonstrating sampling techniques
used by these institutions is gratefully acknowledged.
Disclaimer
This sampling method has been reviewed and approved for publication by the Analytical Methods
Staff within the Engineering and Analysis Division of the U.S. Environmental Protection Agency.
Mention of trade names or commercial products does not constitute endorsement or recommendation
for use.
Further Information
For further information, contact:
William A. Telliard
Engineering and Analysis Division (4303)
U. S. Environmental Protection Agency
401 M St. SW
Washington DC 20460
Phone: 202-260-7134
Fax: 202-260-7185
-------
Method 1669
1.0 SCOPE AND APPLICATION
1.1 This method (Method 1669) is for the collection and filtration of ambient water samples for
subsequent determination of trace metals. It is designed to support the implementation of
water quality monitoring and permitting programs administered under the Clean Water Act.
1.2 Method 1669 is applicable to the metals listed in Table 1 and other metals, metals species,
and elements amenable to determination at trace levels.
1.3 Method 1669 is accompanied by the Quality Control Supplement for Determination of Trace
Metals at EPA Water Quality Criteria Levels Using EPA Metals Methods (the QC
Supplement). The QC Supplement is necessary to assure that trace metals will be determined
reliably when EPA analytical methods are used. Method 1669 contains the QC necessary to
assure that sampling will be performed reliably.
1.4 Method 1669 is not intended for determination of metals at. concentrations normally found in
treated and untreated discharges from industrial facilities. Existing regulations (40 CFR Parts
400 - 500) typically limit concentrations in industrial discharges to the mid to high part-per-
billion (ppb) range, whereas ambient metals concentrations are normally in the low part-per-
trillion (ppt) to low ppb range.
1.5 The ease of contaminating ambient water samples with the metal(s) of interest and interfering
substances cannot be overemphasized. This method includes sampling techniques that should
maximize the ability of the sampling team to collect samples reliably and eliminate sample
contamination., These techniques are given in Section 8.0 and are based on findings of
researchers performing trace metals analyses (References 14.1 - 14.9).
1.6 Clean and ultra-clean—The terms "clean" and "ultra-clean" have been used in other Agency
guidance to describe the techniques needed to reduce or eliminate contamination in trace
metals determinations. These terms are not used in this sampling method due to a lack of
exact definitions. However, the information provided in this method is consistent with
summary guidance oh clean and ultra-clean techniques (Reference 14.10).
1.7 This sampling method follows the EPA Environmental Methods Management Council's
"Format for Method Documentation" (Reference 14.11), and is therefore consistent with the
QC Supplement and the EPA methods that are referenced in the QC Supplement (Referenced
Methods). Where appropriate, sections of this sampling method expand upon sections for
sampling in the Referenced Methods to include the increased operational procedures and QC
necessary for collection of samples for trace metals at ambient WQC levels. In these
instances, the procedures and QC in this sampling method take precedence over the
procedures and QC in the Referenced Methods; otherwise, all procedures and QC in the
Referenced Methods must be followed.
1.8 Method 1669 is "performance-based"; i.e., an alternate sampling procedure or technique may
be used, as long as the performance requirements in the Referenced Methods and the QC
Supplement are met. Section 9.2 gives details of the tests and documentation required to
support equivalent performance.
December 1994
-------
Method 1669
1.9 For dissolved metal determinations, samples must be filtered through a 0.45 jim capsule filter
at the field site. The filtering procedures are described in this method. The filtered samples
may be preserved in the field or transported to the laboratory for preservation. Procedures
, for field preservation are detailed in this sampling method; procedures for laboratory
preservation are provided in.the QC Supplement.
1.10 The procedures in this method are. for use only by personnel thoroughly trained in the
collection of samples for determination of metals at ambient WQC levels.
2.0 SUMMARY OF METHOD
2.1 Prior to sample collection, all sampling equipment and sample containers are cleaned in a
laboratory or cleaning facility using detergent, mineral acids, and reagent water. The
laboratory or cleaning facility is responsible for generating an acceptable equipment blank to
demonstrate that the sampling equipment and containers are free from trace metals
contamination prior to shipping them to the field sampling team (Section 9.3).
2.2 After cleaning, sample containers are filled with weak acid solution, individually double
bagged, and shipped to the sampling site. All sampling equipment is also bagged for storage
or shipment.
2.3 The laboratory or cleaning facility must prepare a large carboy or other appropriate clean
container filled with reagent water for use with collection of field blanks during sampling
activities. The reagent-water-filled container should be shipped to the field site and handled
as all other sample containers and sampling equipment. At least one field blank should be
processed per site, or one per every ten samples, whichever is more frequent (Section 9.4).
If samples are to be collected for determination of trivalent chromium, additional QC aliquots
are processed by the sampling team as described in Section 9.6.
2.4 Upon arrival at the sampling site, one member of the two person sampling team is designated
as "dirty hands"; the second member is designated as "clean hands". AH operations involving
,- contact with the sample bottle and transfer of the sample from the sample collection device to
the sample bottle are handled by the individual designated as "clean hands". "Dirty hands" is
responsible for preparation of the sampler (except the sample container itself), operation of
any machinery, and for all other activities that do not involve direct contact with the sample.
/ • -
2.5 All sampling equipment and sample containers used for metals determinations at ambient
water quality criteria levels must be non-metallic and free from any material that may contain
metals.
2.6 Sampling personnel are required to wear clean, non-talc gloves at all times when handling
sampling equipment and sample containers.
2.7 In addition to processing field blanks at each site, a field duplicate must be collected at each
sampling site, or one field duplicate per every ten samples, whichever is more frequent
(Section 9.5).
December 1994
-------
Method 1669
2.8 Sampling
2.8. 1 Whenever possible, samples are collected facing upstream and upwind to minimize
introduction of contamination.
2.8.2 Samples may be collected while working from a boat or while on land.
2.8.3 Surface samples are collected using a grab sampling technique. The principle of the
grab techniques is to fill a sample bottle by rapid immersion in water and capping to
minimize exposure to airborne paniculate matter.
2.8.4 Subsurface samples are collected by suction of the sample into an immersed sample
bottle or by pumping the sample to the surface.
2.9 Samples for dissolved metals are filtered through a 0.45 nm capsule filter at the field site.
After filtering, the samples are double bagged and iced immediately. Sample containers are
shipped to the, analytical laboratory. The sampling equipment is shipped to the laboratory or
cleaning facility for re-cleaning.
2.10 Acid preservation of samples is performed in the field or in the laboratory. Field preservation
is necessary for determinations of trivalent chromium. It has also been shown that field
preservation can increase sample holding times for hexavalent chromium to 30 .days; therefore
it is recommended that preservation of samples for hexavalent chromium be performed in the
field. For other metals, however, the sampling team may prefer to utilize laboratory
preservation of samples in order to expedite field operations and to minimize the potential for
sample contamination.
2.11 Sampling activities are documented through paper or computerized sample tracking systems.
3.0 DEFINITIONS
3.1 Apparatus— Throughout this sampling method, the sample containers, sampling devices, and
all other materials and devices that will contact the sample will be referred to collectively as
the Apparatus.
3.2 Other definitions of terms are given in the Glossary (Section 15) at the end of this method.
4.0 CONTAMINATION AND INTERFERENCES
4.1 Contamination problems in trace metals analysis
4.1.1 Preventing ambient water samples from becoming contaminated during the sampling
and analytical process is the greatest challenge faced in trace metals determinations.
Over the last two decades, marine chemists have come to recognize that much of the
historical data regarding the concentrations of dissolved trace metals in seawater are
erroneously high because the concentrations reflect contamination from sampling and
analysis rather than ambient levels. More recently, historical^trace metals data
December 1994
-------
Method 1669
collected from freshwater rivers and streams have been shown to be similarly biased
v due to contamination during sampling and analysis (Reference 14.12). Therefore, it is
imperative that extreme care be taken to avoid contamination when collecting and
analyzing ambient water samples for trace metals.
4.1.2 There are numerous routes by which samples may become contaminated. Potential
sources of trace metals contamination during sampling include: metallic or metal-
containing sampling equipment, containers, labware (e.g. talc gloves that contain high
levels of zinc), reagents, and deionized water; improperly cleaned and stored
equipment, labware, and reagents; and atmospheric inputs such as dirt and dust from
automobile exhaust, cigarette smoke, nearby roads, bridges, wires, poles, etc. Even
human contact can be a source of trace metals contamination. For example, it has
been demonstrated that dental work (e.g., mercury amalgam fillings) in the mouths of
laboratory personnel can contaminate samples that are directly exposed to exhalation
(Reference 14.3).
4.2 Contamination Control
4.2.1 Philosophy—The philosophy behind contamination control is to ensure that any object
or substance that contacts the sample is non-metallic and free from any material that
may contain metals.
4.2.1.1 The integrity of the results produced cannot be compromised by
contamination of samples. Requirements and suggestions for control
of sample contamination are given in this sampling method, the QC
Supplement, and the Referenced Methods.
4.2.1.2 Substances in a sample or in the surrounding environment cannot be
allowed to contaminate the Apparatus used to collect samples for trace
metals measurements. Requirements and suggestions for protecting
the Apparatus are given in this sampling method and the QC
Supplement.
4.2.1.3 While contamination control is essential, personnel health and safety
remain the highest priority. Requirements and suggestions for
personnel safety are given in Section 5 of this sampling method, the
QC Supplement, and the Referenced Methods.
4.2.2 Avoiding contamination—The best way to control contamination is to completely
avoid exposure of the sample and Apparatus to contamination in the first place.
Avoiding exposure means performing operations in an area known to be free from
contamination. Two of the most important factors in avoiding/reducing sample
contamination are: (1) an awareness of potential sources of contamination and (2) -
strict attention to work being performed. Therefore, it is imperative that the
procedures described in this method be carried out by well-trained, experienced
personnel. Documentation of training should be kept on file and readily available for
review.
December 1994
-------
Method 1669
4.2.2.1 Minimize exposure—The Apparatus that will contact samples or
blanks should only be opened or exposed in a clean room, clean
bench, glove box, or clean plastic bag, so that exposure to
• . atmospheric inputs is minimized. When not being used, the Apparatus
should be covered with clean plastic wrap, stored in the clean bench
or in a plastic box or glove box, or bagged in clean, colorless zip-type
bags. Minimizing the time between cleaning and use will also reduce
contamination.
4.2.2.2 Wear gloves—Sampling personnel must wear clean, non-talc gloves
(Section 6.7) during all operations involving handling of the
Apparatus, samples, and blanks. Only clean gloves may touch the
Apparatus. If another object or substance is touched, the glove(s)
must be changed before again handling the Apparatus. If it is even
suspected that gloves have become contaminated, work must be
halted, the contaminated gloves removed, and a new pair of clean
gloves put on. Wearing multiple layers of clean gloves will allow the
old pair to be quickly stripped with minimal disruption to the work
activity. .
4.2.2.3 Use metal-free Apparatus—All Apparatus used for metals
determinations at ambient water quality criteria levels must be non-
metallic and free of material that may contain metals.
4.2.2.3.1 Construction materials—Only the following materials
should come in contact with samples:. fluoropolymer
(FEP, PTFE), conventional or linear polyethylene,
polycarbonate, polysulfone, polypropylene, or ultra-
pure quartz. PTFE is less desirable than FEP because
the sintered material in PTFE may contain
contaminants and is susceptible to serious memory
effects (Reference 14.6). Only fluoropolymer should
be used for samples that will be analyzed for mercury
because mercury, vapors can diffuse in or out of other
materials, resulting either in contamination or low-
biased results (Reference 14.3). Glass and metal must
not be used under any circumstance. Regardless of
construction, all materials that will directly or
indirectly contact the sample must be cleaned using the
procedures described in the QC Supplement and must
be known to be clean and metal-free before
proceeding.
4.2.2.3.2 The following materials have been found to contain
trace metals and must not be used to hold liquids that
come in contact with the sample or must not contact
the sample, unless these materials have been shown to
be free of the metals of interest at the desired level:
Pyrex, Kimax, methacrylate, polyvinylchloride, nylon,
December 1994 5
S3
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Method 1669
and Vycor (Reference 14.6). In addition, highly
colored plastics, paper cap liners, pigments used to
mark increments on plastics, and rubber all contain
trace levels of metals and must be avoided (Reference •
14.13).
4.2.2.3.3 . . Serialization—Serial numbers should be indelibly
marked or etched on each piece of Apparatus so that
contamination can be traced, and logbooks should be
maintained to track the sample from the container
through the sampling process to shipment to the
laboratory. Chain-of-custody procedures may also be
used if warranted so that contamination can be traced
to particular handling procedures or lab personnel.
4.2.2.3.4 The Apparatus should be clean when received by the
sampling team. If there are any indications that the
Apparatus is not clean (e.g., ripped storage bags), an
assessment of the likelihood of contamination must be
made. Sampling must not proceed if it is possible that
the Apparatus is contaminated. If the Apparatus is
contaminated, it must be returned to the laboratory or
cleaning facility for proper cleaning before any
sampling activity resumes.
4.2.2.3.5 Details for recleaning the Apparatus between collection
of individual samples are provided in Section 10.
4.2.2.4 Avoid sources of contamination—Avoid contamination by being aware
of potential sources and routes of contamination.
4.2.2.4.1 Contamination by carry-over—Contamination may
occur when a sample containing low concentrations of
metals is processed immediately after a sample
containing relatively high concentrations of these
metals. At sites where more than one sample will be
collected, the sample known or expected to contain the
lowest concentration of metals should be collected first
with the sample containing the highest levels collected
last (Section 8.1.4). This will help minimize carry-
over of metals from high concentration samples to low
concentration samples. When necessary, the sample
collection system may be rinsed with dilute acid and
reagent water between samples followed by collection
of a field blank (Section 10.3).
4.2.2.4.2 Contamination by samples— Significant contamination
of the Apparatus may result when untreated effluents,
in-process waters, landfill leachates, and other samples
6 December 1994
•if
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Method 1669
containing mid- to high-level concentrations of
inorganic substances are processed. As stated in
Section 1, this sampling method is not intended for
application to these samples, and samples containing
high concentrations of metals (> ~ 10 /ig/L) must not
be collected, processed, or shipped at the same time as
samples being collected for trace metals
determinations.
4.2.2.4.3 Contamination by indirect contact— Apparatus that
may not directly contact samples may still be a source
of contamination. For example, clean, tubing placed in
a dirty plastic bag may pick up contamination from the
bag and subsequently transfer the contamination to the
sample. Therefore, it is imperative that every piece of
the Apparatus that is directly or indirectly used in the
collection of ambient water samples be cleaned as
specified in the QC Supplement.
4.2.2.4.4 Contamination by airborne paniculate matter—Less
obvious substances capable of contaminating samples
include airborne particles. Samples may be
contaminated by airborne dust, dirt, paniculate matter,
or vapors from: automobile exhaust; cigarette smoke;
nearby corroded or rusted bridges, pipes, poles, or
wires; nearby roads; and even human breath (Section
4.1.2). Whenever possible, the sampling activity
should occur as far as possible from sources of
airborne contamination (Section 8.1.3). Areas where
nearby soil is bare and subject to wind erosion should
be avoided.
4.3 Analytical interferences—Interferences resulting from samples will vary considerably from
source to source, depending on the diversity of the site being sampled. If a sample is
suspected of containing substances that may interfere in the determination of trace metals,
sufficient sample should be collected to allow the laboratory to identify and overcome
interference problems.
5.0 SAFETY
5.1 The toxicity or carcinogenicity of the chemicals used in this method has not been precisely
determined; however, these chemicals should be treated as a potential health hazard.
Exposure should be reduced to the lowest possible level. Sampling teams are responsible for
maintaining a current awareness file of OSHA regulations regarding the safe handling of the
chemicals specified in this method. A reference file of Material Safety Data Sheets should
also be made available to all personnel involved in sampling.
December 1994
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Method 1669
5.2 Operating in and around water bodies carries the inherent risk of drowning. Life jackets must
be worn when operating from a boat, when .sampling in more than a few feet of water, or
when sampling in swift currents.
5.3 Collecting samples in cold weather, especially around cold water bodies, carries the risk of
hypothermia, and collecting samples in extremely hot and humid weather carries the risk of
dehydration and heat stroke. Sampling team members should wear adequate clothing for
protection in cold weather and should carry an adequate supply of water or other liquids for
protection against dehydration in hot weather.
6.0 APPARATUS AND MATERIALS
NOTE: Brand names, suppliers, and part numbers are for illustration purposes
only and no endorsement is implied. Equivalent performance may be achieved using
apparatus and materials other than those specified here. Meeting the performance
requirements of this method is the responsibility of the sampling team and laboratory.
6.1 All sampling equipment and sample containers must be pre-cleaned in a laboratory or cleaning
facility, as described in the QC Supplement, prior to shipment to the field site. To minimize
difficulties in sampling, the equipment should be packaged and arranged to minimize field
preparation.
6.2 Materials such as gloves (Section 6.7), storage bags (Section 6.8), and plastic wrap (Section
6.9), may be used new without additional cleaning unless the results of the equipment blank
pinpoint any of these materials as a source of contamination. In this case, either a different
supplier must be obtained or the materials must be cleaned.
6.3 Sample bottles—Fluoropolymer (FEP, PTFE), conventional or linear polyethylene,
polycarbonate, or polypropylene; 500-mL or 1-L with lids. Cleaned sample bottles should be
filled with 0.1% HC1 (v/v) until use. Note: If mercury is a target analyte, fluoropolymer
bottles must be used. Refer to the QC Supplement for bottle cleaning procedures.
6.4 Surface sampling devices—Surface samples are collected using a grab sampling technique.
Samples may be collected manually by direct submersion of the bottle into the water or by
using a grab sampling device. Examples of grab samplers are shown in Figures 1 and 2 and
may be used at sites where depth profiling is neither practical nor necessary. Whenever
possible, grab sampling devices should be cleaned and prepared for field use in a class 100
clean room. Preparation of the devices in the field should be done within the glove bag
(Section 6.6). Regardless of design, sampling devices must be constructed of non-metallic
material (Section 4.2.2.3.1) and free from material that contains metals. Commercially
available samplers may be used provided that any metallic or metal-containing parts are
replaced with parts constructed of appropriate material.
6.4.1 The grab sampler in Figure 1 consists of a heavy fluoropolymer collar fastened to the
end of a 2-meter long polyethylene pole, which serves to remove the sampling
personnel from the immediate vicinity of the sampling point. The collar holds the
sample bottle. A fluoropolymer closing mechanism, threaded onto the bottle, enables
the sampler to open and close the bottle under water, thereby avoiding surface
microlayer contamination (Reference 14.14). Polyethylene, polycarbonate, and
8 December 1994
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Method 1669
polypropylene are also acceptable construction materials unless mercury is a target
analyte. Assembly of the cleaned sampling device is as follows (refer to Figure 1):
6.4.1.JL Thread the pull cord (with the closing mechanism attached) through
the guides and secure the pull ring with a simple knot. Screw a
I sample bottle onto the closing device and insert the bottle into the
collar. Cock the closing plate so that the plate is pushed away from
the operator.
6.4.1.2 The cleaned and assembled sampling device should be stored in a
double layer of large, clean zip-type polyethylene bags or wrapped in
two layers of clean polyethylene wrap if it will not be used
immediately.
6.4.2 An alternate grab sampler design is shown in Figure 2. This grab sampler is used for
discrete water samples and is constructed so that a capped clean bottle can be
submerged, the cap removed, sample collected, and bottle recapped at a selected
depth. This device eliminates sample contact with conventional samplers (e.g., Niskin
bottles), thereby reducing the risk of extraneous contamination. Because a fresh bottle
is used for each sample, carryover from previous samples is eliminated (Reference .
14.15).
6.5 Subsurface sampling devices— Subsurface sample collection may be appropriate in lakes and
sluggish deep river environments or where depth profiling is determined to be necessary.
Subsurface samples are collected by pumping the sample into a sample bottle. Examples of
subsurface collection systems include the the jar system device shown in Figure 3 and
described in Section 6.5.1 or the continuous flow apparatus shown in Figure 4 and described
in Section 6.5.2. Whenever possible, sampling devices should be cleaned and prepared for •
field use in a class 100 clean room. Preparation of the devices in the field should be done
within the glove bag (Section 6.6). Regardless of design, sampling devices must be
constructed of non-metallic material (Section 4.2.2.3.1) and free from material that contains
metals. Fluoropolymer or other material shown not to adsorb or contribute mercury must be
used if mercury is a target analyte; otherwise, polyethylene, polycarbonate, or polypropylene
are acceptable. Commercially available sampling devices may be used provided that any
metallic or metal-containing parts are replaced with parts constructed of non-metallic material.
6.5.1 Jar sampler (Reference 14.14)— The jar sampler (Figure 3) is comprised of a heavy
fluoropolymer one-liter jar with a fluoropolymer lid equipped with two 1/4-inch
fluoropolymer fittings. Sample enters the jar through a short length of fluoropolymer
tubing inserted into one fitting. Sample is pulled into the jar by pumping on
fluoropolymer tubing attached to the other fitting. A thick fluoropolymer plate
supports the jar and provides attachment points for a fluoropolymer safety line and
fluoropolymer torpedo counter weight.
6.5.1.1 Advantages of the jar sampler for depth sampling are: (1) all wetted
surfaces are fluoropolymer and can be rigorously cleaned, (2) the
sample is collected into a sample jar from which the sample is readily
recovered, and the jar can be easily re-cleaned, (3) the suction device
(a peristaltic or rotary vacuum pump, Section 6.15) is located in the
December 1994
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Method 1669
boat, isolated from the sampling jar, (4) the sampling jar can be
continuously flushed with sample, at sampling depth, to equilibrate the
system, and (5) the sample does not travel through long lengths of
tubing that are more difficult to clean and keep clean (Reference
14.14). In addition, the device is designed to eliminate atmospheric
contact with the sample during collection.
6.5.1.2 To assemble the cleaned jar sampler, screw the torpedo weight onto
the machined bolt attached to the support plate of the jar sampler.
Attach a section of the 1/4-inch OD tubing to the jar by inserting the
tubing into the fitting on the lid and pushing down into the jar until
approximately 8 cm from the bottom. Tighten the fitting nut securely.
Attach the solid safety line to the jar sampler using a bowline knot to
the loop affixed to the support plate.
6.5.1.3 For the tubing connecting the pump to the sampler, tubing lengths of
up to 12 meters have been used successfully (Reference 14.14).
6.5.2 Continuous-flow sampler (References 14.16 - 14.17)—This sampling system, shown in
Figure 4, consists of a peristaltic or submersible pump and one or more lengths of
pre-cleaned fluoropolymer or styrene/ethylene/butylene/silicone (SEBS) tubing. A
filter is added to the sampling train when sampling for dissolved metals.
6.5.2.1 Advantages of this sampling system include (1) all wetted surfaces are
fluoropolymer or SEBS and can be readily cleaned, (2) the suction
device is located in the boat, isolated from the sample bottle, (3) the
sample does not travel through long lengths of tubing that are difficult
to clean and keep clean, and (4) in-line filtration is possible,
minimizing field handling requirements for dissolved metals samples.
6.5.2.2 Assembly of the system is performed in the field by the sampling team
as described in Section 8.2.8. System components include an optional
polyethylene pole to remove sampling personnel from the immediate
vicinity of the sampling point and the pump, tubing, filter, and filter
holder listed in Sections 6.14 and 6.15.
6.6 Field portable glove bag—I2R, Model R-37-37H (non-talc), or equivalent. Alternately, a
portable glove box may be constructed with a non-metallic (PVC pipe or other suitable
material) frame and a frame cover made of an inexpensive, disposable, non-metallic material
(e.g., a thin-walled polyethylene bag) (Reference 14.7).
6.7 Gloves—clean, non-talc polyethylene, latex, vinyl, or PVC; various lengths. Shoulder-length
gloves are needed if samples are to be collected by direct submersion of the sample bottle into
the water or when sampling for mercury.
6.7.1 Gloves, shoulder-length polyethylene—Associated Bag Co., Milwaukee, WI, 66-3-
301, or equivalent.
6.7.2 Gloves, PVC—Fisher Scientific Part No. 11-394-100B, or equivalent.
10 December 1994
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Method 1669
6.8 Storage bags—clean, zip:type, non-vented, colorless polyethylene (various sizes).
6.9 Plastic wrap—clean, colorless polyethylene.
»
6.10 Cooler—clean, non-metallic for shipping samples.
6.11 Ice or chemical refrigerant packs—to keep samples chilled in the cooler during shipment.
6.12 Wind suit—Pamida, or equivalent.
6.12.1 An unlined, long-sleeved wind suit consisting of pants and jacket and constructed of
nylon or other synthetic fiber is worn when sampling for mercury to prevent mercury
adsorbed onto cotton or other clothing materials from contaminating samples.
6.12.2 Washing and drying—The wind suit is washed by itself or with other wind suits only
in a home or commercial washing machine and dried in a clothes drier. The clothes
drier must be thoroughly vacuumed, including the lint filter, to remove all traces of
lint prior to drying. After drying, the wind suit is folded and stored in a clean,
polyethylene bag for shipment to the sample site.
6.13 Boat
6.13.1 Only metal-free (e.g., fiberglass) boats should be used, along with wooden or
fiberglass oars. A flat-bottom, Boston Whaler type boat is preferred because sampling
materials can be stored with reduced chance of tipping over. Gasoline or diesel fueled
' boat motors should be avoided when possible because the exhaust can be a source of
contamination. If the body of water is so large as to necessitate the use of a boat
motor, the engine should be shut off at a distance far enough from the sampling point
as to avoid contamination, and the sampling team should manually propel the boat to
the sampling point. Samples should be collected upstream of boat movement.
6.13.2 Before first use, the boat should be cleaned and stored in an area that minimizes
exposure to dust and atmospheric particles. For example, cleaned boats should not be
stored in an area that would, allow exposure to automobile exhaust or industrial
pollution.
-6.13.3 The boat should be frequently visually inspected for possible contamination.
Immediately before use, the boat should be washed down with water from the
sampling site away from any sampling points to remove any dust or dirt accumulation.
6.13.4 After sampling, the boat should be returned to the laboratory or cleaning facility,
cleaned as necessary, and stored away from any sources of contamination until next
use.
6.14 Filtration Apparatus—Required when collecting samples for dissolved metals determinations.
6.14.1 Filter—0.45 /mi, 15 him diameter or larger, tortuous path capsule filters (Reference
14.18), Gelman Supor 12175, or equivalent.
December 1994 11
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Method 1669
6.14.2 Filter holder for mounting filter to the gunwale of the boat—Rod or pipe made from
plastic material and mounted with plastic clamps. Note: A filter holder may not be
required if one or a few samples are to be collected. For these cases, it may only be
necessary to attach the filter to the outlet of the tubing connected to the pump.
6.15 Pump and pump apparatus—Required for use with the jar sampling system (Section 6.5.1) or
the continuous flow sytem (Section 6.5.2). Peristaltic pump—115 a.c, 12 volt d.c., internal
battery, variable speed, single-head, Cole-Parmer, portable, "Masterflex L/S", Catalog No.
H-07570-10 drive with Quick Load pump head, Cat. No. H-07021-24, or equivalent. (Note:
equivalent pumps may include rotary vacuum, submersible, or other pumps suitable to meet
the site-specific depth sampling needs.)
6.15.1 Cleaning—Peristaltic pump modules do not require cleaning. However, nearly all
peristaltic pumps contain a metal head and metal controls. Touching the head or
controls necessitates changing of gloves before touching the Apparatus. If a
submersible pump is used, then a large quantity of .reagent water should be passed
through the pump in order to clean the stainless steel shaft (hidden behind the
impeller) that comes in contact with the sample. Users of such pumps should
recognize, however, that even with such cleaning, a stainless steel impeller may
present contamination problems when sampling for certain metals (such as chromium);
in these cases, an alternate type of pump must be used.
6.15.2 Tubing for use with peristaltic pump—SEES resin, approximately 3/8 inch ID by
approximately 3 ft, Cole-Parmer size 18, Cat. No. G-06464-18, or approximately 1/4
inch ID, Cole-Parmer size 17, Cat. No. G-06464-17, or equivalent. Tubing is
cleaned by soaking in 5 - 10 percent HC1 solution for 8 - 24 h, rinsing with reagent
water in a clean bench in a clean room, and drying in the clean bench by purging with
mercury-free air or nitrogen. After drying, the tubing is double-bagged in clear
polyethylene bags, serialized with a unique number, and stored until use.
6.15.3 Tubing for connection to peristaltic pump tubing—fluoropolymer, 3/8 inch or 1/4 inch
OD, in lengths as required to reach the point of sampling. If sampling will be at
some depth from the end of a boom extended from a boat, sufficient tubing to extend
to the end of the boom and to the depth will be required. Cleaning of PTFE can be
the same as cleaning the tubing for the rotary vacuum pump (Section 6.15.1.2). If
necessary, more agressive cleaning (e.g., concentrated nitric acid) may be used.
6.15.4 Batteries to operate pump—12 volt, 2.6 amp, gel cell, YUASA NP2.6-12, or
equivalent. A 2-amp fuse connected at the positive battery terminal is strongly
recommended to prevent short circuits from overheating the battery. A 12-volt, lead-
acid automobile or marine battery may be more suitable for extensive pumping.
6.15.5 Tubing connectors—appropriately sized PVC, clear polyethylene, or fluoropolymer
"barbed" straight connectors cleaned as the tubing above. Used to connect multiple
lengths of tubing. .
6.16 Carboy for collection and storage of dilute waste acids used to store bottles.
12 December 1994
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Method 1669
6.17 Apparatus for field preservation of aliquots for trivalent chromium determinations
6.17.1 Fluoropolymer forceps,, 1-L fluoropolymer jar, and 30-mL fluoropolymer vials with
screw caps (1 vial per sample and blank). It is recommended that 1 mL of ultra-pure
nitric acid (Section 7.3) be added to each vial prior to transport to the field in order to
simplify field handling activities (See Section 8.4.4.6).
6.17.2 Filters—0.4 micron, 47-mm polycarbonate Nucleopore (or equivalent). Filters are
cleaned as follows. Fill a 1-L fluoropolymer jar approximately 2/3 full with 1-N
nitric acid. Using fluoropolymer forceps, place individual filters in the fluoropolymer
jar. Allow the filters to soak for 48 hours. Discard the acid, and rinse five times
with reagent water. Fill the jar with reagent water, and soak the filters for 24 hours.
Remove the filters when ready for use, and using fluoropolymer forceps, place them
on the filter apparatus (Section 6.17.3).
6.17.3 Vacuum filtration apparatus— Millipore 47 mm size, or equivalent, vacuum pump and
power source (and extension cords, if necessary) to operate the pump.
6.17.4 Eppendorf auto pipet and colorless pipet tips (100 - 1,000 /zL)
6.17.5 Wrist-action shaker—Burrel or equivalent.
6.17.6 Fluoropolymer wash bottles—one filled with reagent water (Section 7.1) and one filled
with high purity 10% HC1 (Section 7.4.4), for use in rinsing forceps and pipet tips.
7.0 REAGENTS AND STANDARDS
7.1 Reagent water—water in which the analytes of interest and potentially interfering substances
are not detected at the Method Detection Limit (MDL) of the analytical method used for
analysis of samples. Prepared by distillation, deionization, reverse osmosis, anodic/cathodic
stripping voltammetry, or other techniques that remove the metal(s) and potential
interferent(s). A large carboy or other appropriate container filled with reagent water must be
available for the collection of field blanks.
7.2 Nitric acid, dilute, trace-metal grade—Shipped with sampling kit for cleaning equipment
between samples.
7.3 Sodium hydroxide—For use when field preserving samples for hexavalent chromium
determinations (Section 8.4.5).
7.4 Reagents for field processing aliquots for trivalent chromium determinations
7.4.1 Nitric acid, ultra-pure—For use when field preserving samples for trivalent chromium
determinations (Sections 6.17 and 8.4.4).
7.4.2 Ammonium iron (II) sulfate solution (0.01M)—Used to prepare the chromium (III)
extraction solution (Section 7.4.3) necessary for field preservation of samples for
trivalent chromium (Section 8.4.4). Prepare the ammonium iron (II) sulfate solution
December 1994 13
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Method 1669
by adding 3.92 g ammonium iron (II) sulfate (ultrapure grade) to a 1-L volumetric
flask. Bring to volume with reagent water. Store in a clean polyethylene bottle.
7.4.3 Chromium (HI) extraction solution—For use when field preserving samples for
trivaleht Chromium determinations (Section 8.4.4). Prepare this solution by adding
100 mL of ammonium iron (II) sulfate solution (Section 7.4.2) to a 125-mL
polyethylene bottle. Adjust pH to 8 with approximately 2 mL of ammonium
hydroxide solution. Cap and shake on a wrist-action shaker for 24 hours.. This iron
(III) hydroxide solution is stable for 30 days.
7.4.4 Hydrochloric acid—High purity, 10% solution—shipped with sampling kit in
fluoropolymer wash bottles for cleaning triyalent chromium sample preservation
equipment between samples.
7.4.5 Chromium stock standard solution (1000 /*gAnL)-Prepared by adding 3.1 g, anhydrous
chromium chloride to a 1-L flask and diluting to volume with 1 % hydrochloric acid.
Store in polyethylene bottle. A commercially available standard solution may be
substituted.
7.4.6 Standard chromium spike solution (1000 /zg/L)-Used to spike sample aliquots for
matrix spike/matrix spike duplicate (MS/MSD) analysis and to prepare ongoing
precision and recovery standards. Prepared by spiking 1 mL of the chromium stock
standard solution (Section 7.4.5) into a 1-L flask. Dilute to volume with 1% HC1.
Store in a polyethylene bottle.
7.4.7. Ongoing precision and recovery (OPR) standard (25 /ig/L)-Prepared by spiking 2.5
mL of the standard chromium spike solution (Section 7.4.6) into a 100-mL flask.
Dilute to volume with 1% HC1. One OPR is required for every ten samples.
8.0 SAMPLE COLLECTION, FILTRATION, AND HANDLING
8.1 Site selection
8.1.1 Selection of a representative site for surface water'sampling is based on many factors
including: study objectives, water use, point source discharges, nonpoint source
discharges, tributaries, changes in stream characteristics, types of stream bed, stream
depth, turbulence, and the presence of structures (bridges, dams, etc.). When
collecting samples to determine ambient levels of trace metals, the presence of
potential sources of metal contamination are of extreme importance in site selection.
8.1.2 Ideally, the selected sampling site will exhibit a high degree of cross-sectional
homogeneity. It may be possible to use previously collected data to identify locations
for samples that are well-mixed or are vertically or horizontally stratified. Since
mixing is principally governed by turbulence and water velocity, the selection of a site
immediately downstream of a riffle area will ensure good vertical mixing. Horizontal
mixing occurs in constrictions in the channel. In the absence of turbulent areas, the
selection of a site that is clear of immediate point sources, such as industrial effluents,
is preferred for the collection of ambient water samples (Reference 14.19).
14 . December 1994
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Method 1669
8.1.3 In order to minimize atmospheric trace metals contamination, ambient water samples
should be collected from sites that are as far as possible (e.g., at least several hundred
feet) from any metal supports, bridges, wires or poles. Similarly, samples should be
collected as far as possible from regularly or heavily traveled roads. If it is not
possible to avoid collection near roadways, it is advisable to study traffic patterns and
plan sampling events during lowest traffic flow (Reference 14.7).
8.1.4 The sampling activity should be planned to collect samples known or suspected to
contain the lowest concentrations of trace metals first, finishing with the samples
known or suspected to contain the highest concentrations. For example, if samples
are collected from a flowing river or stream near an industrial or municipal discharge,
the upstream sample should be collected first, the downstream sample collected
second, and the sample nearest the discharge collected last.
8.2 Sample.collection procedure—Prior to collection of ambient water samples, consideration
should be given to the type of sample to be collected, the amount of sample needed, and the
devices to be used (grab, surface, or subsurface samplers). Sufficient sample volume should
be collected to allow for necessary quality control analyses, .such as matrix spike/ matrix spike
duplicate analyses.
8.2.1 Four (4) sampling procedures are described:
8.2.1.1 Section 8.2.5 describes a procedure for collecting samples directly into
the sample container. This procedure is the simplest and provides the
least potential for contamination because it requires the least amount
of equipment and handling.
8.2.1.2 Section 8.2.6 describes a procedure for using a grab sampling device
to collect samples.
8.2.1.3 Section 8.2.7 describes a procedure for depth sampling with a jar
sampler. The size of sample container used is dependent on the
amount of sample needed by the analytical laboratory.
8.2.1.4 Section 8.2.8 describes a procedure for continuous-flow sampling
using a submersible or peristaltic pump.
8.2.2 The sampling team should ideally approach the site from down current and downwind
in order to prevent contamination of the sample by particles sloughing off the boat or
equipment. If it is not possible to approach from both, the site should be approached
from down current if sampling from a boat or approached from downwind if sampling
on foot. When sampling from a boat, the bow of the boat should be oriented into the
current (the boat will be pointed upstream). All sampling activity should occur from
the bow.
If the samples are being collected from a boat, it is recommended that the
sampling team create a stable workstation by arranging the cooler or shipping
container as a work table on the upwind side of the boat, covering this work
table and the upwind gunnel with plastic wrap or a plastic tablecloth, and
December 1994 15
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Method 1669.
draping the wrap or cloth over the gunnel. If necessary, duct tape is used to
hold the wrap or cloth in place.
8.2.3 All operations involving contact with the sample bottle and with transfer of the sample
from the sample collection device to the sample bottle (if the sample is not directly
collected in the bottle) are handled by the individual designated as "clean hands".
"Dirty hands" is responsible for all activities that do not involve direct contact with
the sample.
Initially, this appears to be a fairly clear-cut and separate division of
responsibilities. In fact, the completion of the entire protocol may require a
good deal of coordination and practice (e.g., "dirty hands" must open the box
or cooler containing the sample bottle and unzip the outer bag; clean hands
must reach into the outer bag, open the inner bag, remove the bottle, collect
the sample, replace the bottle lid, put the bottle back into the inner bag, and
zip the inner bag. Dirty hands must close the outer bag and place it in a
cooler).
To minimize unnecessary confusion, it is recommended that a third team
member be available to complete the necessary sample documentation (e.g., to
document sampling location, time, sample number, etc). Otherwise, the
sample documentation activity must be performed by "dirty hands" (Reference
14.7).
8.2.4 Extreme care must be taken during all sampling operations to minimize exposure of
the sample to human, atmospheric, and other sources of contamination. Care must be
taken to avoid breathing directly on the sample, and whenever possible, the sample
bottle should be opened; filled, and closed while submerged.
8.2.5 Manual collection of surface samples directly into the sample bottle
8.2.5.1 At the site, all sampling personnel must put on clean gloves (Section
6.7) prior to commencing sample collection activity, with "clean
hands" donning shoulder-length gloves. If samples are to be analyzed
for mercury, the sampling team must also put their pre-cleaned
windsuits on at this time. Note that "clean hands" should put on the
shoulder-length polyethylene gloves (Section 6.7.1) and both "clean
hands" and "dirty hands" should put on the PVC gloves (Section
6.7.2).
8.2.5.2 "Dirty hands" must open the cooler or storage container, remove the
double bagged sample bottle from storage, and unzip the outer bag.
8.2.5.3 Next, "clean hands" opens the inside bag containing the sample bottle,
removes the bottle, and reseals the inside bag. "Dirty hands" then
reseals the outer bag.
16 . . December 1994
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Method 1669
8.2.5.4 "Clean hands" unscrews the cap and, while holding the cap upside
down, discards the dilute acid solution from the bottle into a carboy
for wastes (Section 6.16).
8.2.5.5 "Clean hands" then submerges the sample bottle, and allows the bottle
to partially fill with sample. "Clean hands" screws the cap on the
bottle, shakes the bottle several times, and empties the rinsate away
from the site. After two more rinsings, "clean hands" holds the bottle
under water and allows bottle to fill with sample. After the bottle has
filled (i.e., when no more bubbles appear), and while the bottle is still
inverted so that the mouth of the bottle is underwater, "clean hands"
replaces the cap of the bottle. In this way, the sample has never
contacted the air.
8.2.5.6 Once the bottle lid has been replaced, "dirty hands" re-opens the outer
plastic bag, and "clean hands" opens the inside bag, places the bottle
inside it, and zips the inner bag.
8.2.5.7 "Dirty hands" zips the outer bag.
8.2.5.8 Documentation—after each sample is collected, the sample number is
documented in the sampling log, and any unusual observations
concerning the sample and the sampling are documented.
8.2.5.9 If the sample is to be analyzed for dissolved metals, it is filtered in
accordance with the procedure described in Section 8.3.
8.2.6 Sample collection with grab sampling device (Figure 1 and Section 6.4.1)—The
following steps detail samle collection using the grab sampling device shown in Figure
1 and described in Section 6.4.1. The procedure is indicative of the "clean
hands/dirty hands" technique that must be used with alternative grab sampling devices
such as that shown in Figure 2 and described in Section 6.4.2.
8.2.6.1 . The sampling team puts on gloves (and windsuits, if applicable) and
handles bottles as with manual collection (Sections 8.2.5.1 - 8.2.5.4
and 8.2.5.6 - 8.2.5.7).
8.2.6.2 "Dirty hands" removes the sampling device from its storage container
and opens the outer polyethylene bag.
8.2.6.3 "Clean hands" opens the inside polyethylene bag and removes the
sampling device. Ideally, a sample bottle will have been pre-attached
to the sampling device in the class 100 clean room at the laboratory.
If it is necessary to attach a bottle to the device in the field "clean
hands" performs this operation, described in Section 6.4.2, inside the
field-portable glove bag (Section 6.6).
8.2.6.4 "Clean hands" changes gloves.
December 1994 17
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Method 1669
8.2.6.5 "Dirty hands" submerges the sampling device to the desired depth and
pulls the fluoropolymer pull-cord to bring the seal plate into the
middle position so that water can enter the bottle.
8.2.6.6 ' When the bottle is full (i.e., when no more bubbles appear), "dirty
hands" pulls the fluoropolymer cord to the final stop position to seal
off the sample and removes the sampling device from the water.
8.2.6.7 "Dirty hands" returns the sampling device to its large inner plastic
bag, "clean hands" pulls the bottle out of the collar, unscrews the
bottle from the sealing device, and caps the bottle. "Clean hands" and
"dirty hands" then return the bottle to its double-bagged storage as
described in Sections 8.2.5.6 - 8.2.5.7.
8.2.6.8 Closing mechanism: "Clean hands" removes the closing mechanism
from the body of the grab sampler, rinses the device with reagent
water (Section 7.1), places it inside a new clean plastic bag, zips the
bag, and places the bag inside an outer bag held by "dirty hands".
"Dirty hands" zips the outer bag and places the double bagged closing
mechanism in the equipment storage box.
8.2.6.9 Sampling device: "Clean hands" seals the large inside bag containing
the collar, pole, and cord and places the bag into a large outer bag
held by "dirty hands". "Dirty hands" seals the outside bag and places
the double, bagged sampling device into the equipment storage box.
8.2.6.10 Documentation—after each sample is collected, the sample number is
documented in the sampling log, and any unusual observations
concerning the sample and the sampling are documented. .
8.2.6.11 If the sample is to be analyzed for dissolved metals, it is filtered in
accordance with the procedures described in Section 8.3.
8.2.7 Depth sampling using ajar sampling device (Figure 3 and Section 6.5.1)
8.2.7.1 The sampling team puts on gloves (and windsuits, if applicable) and
handles bottles as with manual collection (Sections 8.2.5.1 - 8.2.5.4
and 8.2.5.6 - 8.2.5.7).
8.2.7.2 "Dirty hands" removes the jar sampling device from its storage
container and opens the outer polyethylene bag.
8.2.7.3 "Clean hands" opens the inside polyethylene bag arid removes the jar
sampling apparatus. Ideally, the sampling device will have been pre-
assembled in a class 100 clean room at the laboratory. If, however, it
is necessary to assemble the device in the field, then "clean hands"
must perform this operation, described in Section 6.5.2, inside a field-
portable glove bag (Section 6.6).
18 . December 1994
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Method 1669
8.2.7.4 While "dirty hands" is holding the jar sampling apparatus, "clean
hands" connects the pump to the to the 1/4-inch OD flush line.
8.2.7.5. "Dirty hands" lowers the weighted sampler to the desired depth.
8.2.7.6 "Dirty hands" turns on the pump allowing a large volume (>2 liters)
of water to pass through the system.
8.2.7.7 After stopping the pump, "dirty hands" pulls up the line, tubing, and
device and places them into either a field-portable glove bag or a
large, clean plastic bag as they emerge.
8.2.7.8 Both "clean hands" and "dirty hands" change gloves.
8.2.7.9 Using the technique described in Sections 8.2.5.2 - 8.2.5.4, the
sampling team removes a sample bottle from storage, and "clean
hands" places the bottle into the glove bag.
8.2.7.10 , "Clean hands" tips the sampling jar and dispenses the sample through
the short length of fluoropolymer tubing into the sample bottle.
8.2.7.11 . Once the bottle is filled, "clean hands" replaces the cap of the bottle,
returns the bottle to the inside polyethylene bag, and zips the bag.
"Clean hands" returns the zipped bag to the outside polyethylene bag
held by "dirty hands".
8.2.7.12 "Dirty hands" zips the outside bag. If the sample is to be analyzed for
dissolved metals, it is filtered as described in Section 8.3.
8.2.7.13 Documentation—after each sample is collected, the sample number is
documented in the sampling log, and any unusual observations
concerning the sample and the sampling are documented.
8.2.8 Continuous-flow sampling (Figure 4 and Section 6.5.2)—The continuous-flow
sampling system uses peristaltic pump (Section 6.15) to pump sample to the boat or to
shore through the SEBS-resin or PTFE tubing.
8.2.8.1 Prior to putting on wind suits or gloves, the sampling team removes
the bags containing the pump (Section 6.15), SEBS-resin tubing
(Section 6.15.2), batteries (Section 6.15.4), gloves (Section 6.7),
plastic wrap (Section 6.9), wind suits (Section 6.12), and, if samples
are to be filtered, the filtration apparatus (Section 6.14) from the
coolers or storage containers in which they are packed.
8.2.8.2 "Clean hands" and "dirty hands" put on the wind suits and PVC
gloves (Section 6.7.2).
8.2.8.3 "Dirty hands" removes the pump from its storage bag, and opens the
bag containing the SEBS-resin tubing.
December 1994 19
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Method 1669
8.2.8.4 "Clean hands" installs the tubing while "dirty hands" holds the pump.
"Clean hands" immerses the inlet end of the tubing in the sample
stream.
8.2.8.5 ' Both "clean hands" and "dirty hands" change gloves. "Clean hands"
also puts on shoulder length polyethylene gloves (Section 6.7.1).
8.2.8.6 "Dirty hands" turns the pump on and allows the pump to run for 5 -
10 minutes or longer to purge the pump and tubing.
8.2.8.7 If the sample is to be filtered, clean hands installs the filter at the end
of the tubing, and dirty hands sets up the filter holder on the gunwhale
as shown in Figure 4. Note: The filtration apparatus is not attached
. until immediately prior to sampling to prevent buildup of particulates
from clogging the filter.
8.2.8.8 The sample is collected by rinsing the sample bottle and cap three
times and collecting the sample from the flowing stream.
8.2.8.9 Documentation—after each sample is collected, the sample number is
documented in the sampling log, and any unusual observations
concerning the sample and the sampling are documented.
8.3 Sample filtration—The filtration procedure described below is used for samples collected using
the manual (Section 8.2.5), grab (Section 8.2.6), or jar (Section 8.2.7) collection systems
(Reference 14.7). In-line filtration using the continuous-flow approach is described in Section
8.2.8.7. Because of the risk of contamination, it is recommended that samples for mercury
be shipped unfiltered via overnight courier and filtered upon receipt at the laboratory.
8.3.1 Set up the filtration system inside the glove bag, using the shortest piece of pump
tubing as is practical. Place the peristaltic pump immediately outside of the glove bag
and poke a small hole in the glove bag for passage of the tubing. Also, attach a short
length of tubing to the outlet of the capsule filter.
8.3.2 "Clean hands" removes the water sample from the inner storage bag using the
technique described in Sections 8.2.5.2 - 8.2.5.4 and places the sample inside the
glove bag. "Clean hands" also places two clean empty sample bottles, a bottle
containing reagent water, and a bottle for waste in the glove bag.
8.3.3 "Clean hands" removes the lid of the reagent water bottle and places the end of the
pump tubing in the bottle.
8.3.4 "Dirty hands" starts the pump and passes approximately 200 mL of reagent water
through the tubing and filter into the waste bottle. "Clean hands" then moves the
outlet tubing to a clean bottle and collects the remaining reagent water as a blank.
"Dirty hands" stops the pump.
8.3.5 "Clean hands" removes the lid of the sample bottle and places the intake end of the
tubing in the bottle.
20 December 1994
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Method 1669
8.3.6 "Dirty hands" starts the pump and passes approximately 50 mL through the tubing
and filter into the remaining clean sample bottle and then stops the pump. "Clean
hands" uses the filtrate to rinse the bottle, discards the waste sample, and returns the
outlet tube to the sample bottle.
8.3.7 "Dirty hands" starts the pump and the remaining sample is processed through the
filter and collected in the sample bottle. If preservation is required, the sample is
acidified at this point (Section 8.4).
8.3.8 "Clean hands" replaces the lid on the bottle, returns the bottle to the inside bag, and
zips the bag. "Clean hands" then places the zipped bag ,into the outer bag held by
"dirty hands."
8.3.9 "Dirty hands" zips the outer bag, and places the double bagged sample bottle into a
clean, ice-filled cooler for immediate shipment to the laboratory.
8.3.10 Note: It is not advisable to re-clean and re-use filters. The difficulty and risk
associated with failing to properly clean these devices far outweighs the cost of
purchasing new equipment.
8.4 Preservation
8.4.1 Field preservation is not necessary for dissolved metals, except for trivalent and
hexavalent chromium, provided that the sample is preserved in the laboratory and
allowed to stand for at least two days in order to allow the metals adsorbed to the
container walls to redissolve. Field preservation is advised for hexavalent chromium
in order to provide sample stability for up to 30 days. Mercury samples should be
shipped via overnight courier and preserved upon receipt at the laboratory.
8.4.2 If field preservation is required, preservation must be performed in the glove bag or
in a designated clean area, with gloved hands, as rapidly as possible to preclude
particulates from contaminating the sample. For preservation of trivalent chromium,
the glove bag or designated clean area must be large enough to accomodate the
vacuum filtration apparatus (Section 6.17.3), and an area should be available for
setting up the wrist-action shaker (Section 6.17.5). It is also advisable to set up a
work area that contains a "clean" cooler for storage of clean equipment, a "dirty"
cooler for storage of "dirty" equipment, and a third cooler to store samples for
shipment to the laboratory.
8.4.3 Preservation .of aliquots for metals other than trivalent and hexavalent chromium:
Using a disposable, pre-cleaned, plastic pipette, add 5 mL of a 10 percent solution of
ultra-pure nitric acid in reagent water per liter of sample. This will be sufficient to
preserve a neutral sample to pH <2.
8.4.4 Preservation of aliquots for trivalent chromium (References 14.8 - 14.9)
8.4.4.1 Decant 100 mL of the sample into a clean polyethylene bottle.
December 1994 21
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Method 1669
8.4.4.2 Clean an Eppendorf pipet by pipeting 1 mL of 10% HC1 (Section
(7.4.4) followed by 1 mL of reagent water into an acid waste
container. Use the rinsed pipet to add 1 mL of chromium (III)
extraction solution (Section 7.4.3) to each sample and blank.
8.4.4.3 Cap each bottle tightly, place in a clean polyethylene bag, and shake
on a wrist action shaker (Section 6.17.5) for 1 hour.
8.4.4.4 Vacuum-filter the precipitate through a 0.4 /xm pretreated filter
membrane (Section 6.17.2), using fluoropolymer forceps (Section
6.17.1) to handle the membrane, and a 47-mm vacuum filtration
apparatus with a precleaned filter holder (Section 6.17.3). After all
sample has filtered, rinse the insides of the filter holder with
approximately 15 mL of reagent water.
8.4.4.5 Using the fluoropolymer forceps, fold the membrane in half and then
in quarters, taking care to avoid touching the side containing the
filtrate to any surface. (Folding is done while the membrane is sitting
on the filter holder and allows easy placement of the membrane into
the sample vial). Transfer the filter to a 30-mL fluoropolymer vial.
If the fluoropolymer vial was not pre-equipped with the ultra-pure
nitric acid (Section 7.4.1), rinse the pipet by drawing and discharging
1 mL of 10% HC1 followed by 1 mL of reagent water into a waste
container, and add 1 mL of ultra-pure nitric acid to the sample vial.
8.4.4.6 Cap the vial and double bag it for shipment to the laboratory.
8.4.4.7 Repeat steps 8.4.4.4 through 8.4.4.6 for each sample, rinsing the
fluropolymer forceps and the pipet with 10% high purity HC1
followed by reagent water between samples.
8.4.5 Preservation of aliquots for hexavalent chromium (Reference 14.20)
8.4.5.1 Decant 125 mL of sample into a clean polyethylene bottle.
8.4.5.2 Prepare an Eppendorf pipet by pipeting 1 mL of 10% HC1 (Section
7.4.4) followed by 1 mL of reagent water into an acid waste
container. Use the rinsed^pipet to add 1 mL NaOH to each 125-mL
sample and blank aliquot.
8.4.5.3 Cap the vial(s) and double bag for shipment to the laboratory.
9.0 QUALITY ASSURANCE/QUALITY CONTROL
9.1 The sampling team shall employ a strict quality assurance/ quality control (QA/QC) program.
The minimum requirements of this program include the collection of equipment blanks, field
blanks, and field replicates. It is also desirable to include blind QC samples as part of the
program. If samples will be processed for trivalent chromium determinations, the sampling
22 December 1994
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Method 1669
team shall also prepare method blank, OPR, and MS/MSD samples as described in Section
9.6.
9.2 ' The sampling team is permitted to modify the sampling techniques described in this method to
improve performance or reduce sampling costs, provided that reliable analyses of samples are
obtained and that samples and blanks are not contaminated. Each time a modification is made
to the protocols, the sampling team is required to demonstrate that the modification does not
result in contamination of field and equipment blanks. The requirements for modification are
given in Sections 9.3 and 9.4. Because the acceptability of a modification is based on the
results obtained with the modification, the sampling team must work with an analytical
laboratory capable of making trace metals determinations to demonstrate equivalence.
9.3 Equipment Blanks
9.3.1 Prior to the use of any sampling equipment at a given site, the laboratory or
equipment cleaning contractor is required to generate equipment blanks in order to
demonstrate that the equipment is free from contamination. Two types of equipment
blanks are required: bottle blanks and sampling equipment blanks.
9.3.2 Equipment blanks must be run on all equipment that will be used in the field. If, for
example, samples are to be collected using both a grab sampling device and the jar
sampling device, then an equipment blank must be run on both pieces of equipment.
9.3.3 Equipment blanks are generated in the laboratory or at the equipment cleaning
contractor's facility by processing reagent water through the equipment using the same
procedures that are used in the field (Section 8). Therefore, the "clean hands/dirty
hands" technique utilized during field sampling should be followed when preparing
equipment blanks at the laboratory or cleaning facility.
9.3.4 Detailed procedures for collecting equipment blanks are given in the QC Supplement.
9.3.5 The equipment blank must be analyzed using the procedures given in the QC
Supplement and the Referenced Methods. If any metal(s) of interest or any potentially
interfering substance is detected in the equipment blank at the minimum level
specified in the QC Supplement, the source of contamination/ interference must be
identified and removed. The equipment must be demonstrated to be free from the
metal(s) of interest before the equipment may be used in the field.
9.4 Field Blank
9.4.1 In order to demonstrate that sample contamination has not occurred during field
sampling and sample processing, at least one (1) field blank must be generated for
every ten (10) samples that are collected at a given site. Field blanks are collected
prior to sample collection.
9.4.2 Field blanks are generated by filling a large carboy or other appropriate container
with reagent water (Section 7.1) in the laboratory, transporting the filled container to
the sampling site, processing the water through each of the sample processing steps
and equipment (e.g., tubing, sampling devices, filters, etc.) that will be used in the
December 1994 23
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Method 1669
field, collecting the field blank in one of the sample bottles, and shipping the bottle to
the laboratory for analysis in accordance with the QC Supplement and Referenced
Methods. For example, manual grab sampler field blanks are collected by directly
. submerging a sample bottle into the water, filling the bottle, and capping. Subsurface
sampler field blanks are collected by immersing the tubing into the water and pumping
water into a sample container.
9.4.3 Filter the field blanks using the procedures described in Section 8.3.
9.4.4 If it is necessary to acid clean the sampling equipment between samples (Section 10),
a field blank should be collected after the cleaning procedures but before the next
sample is collected. -
9.4.5 If trivalent chromium aliquots are processed, a separate field blank must be collected
and processed through the sample preparation steps given in Sections 8.4.4.1 -
8.4.4.6.
9.5 Field Duplicate
9.5.1 In order to assess the precision of the field sampling and analytical processes, at least
one (1) field duplicate sample must be collected for every ten (10) samples that are
collected at a given site.
9.5.2 The field duplicate is collected either by splitting a larger volume into two aliquots in
the glove box, by using a sampler with duel inlets that allows simultaneous collection
of two samples, or by collecting two samples in rapid succession.
9.5.3 Field duplicates for dissolved metals determinations must be processed through the
. procedures described in Section 8.3. Field duplicates for trivalent chromium must be
processed through the sample preparation steps given in Sections 8.4.4.1 - 8.4.4.6.
9.6 Additional QC for Collection of Trivalent Chromium Aliquots
9.6.1 Method Blank—The sampling team must prepare one method blank for every ten field
samples, or one per sample set, whichever is more frequent. Each method blank is
prepared by performing the preparation steps given in Sections 8.4.4.1 - 8.4.4.6 on a
100 mL aliquot of reagent water (Section 7.1). Do not utilize the procedures in
Section 8.3 to process the method blank through the 0.45 /xm filter (Section 6.14.1),
even if samples are being collected for dissolved metals determinations.
9.6.2 Ongoing Precision and Recovery (OPR)—The sampling team must prepare one OPR
for every ten field samples, or one per sample set, whichever is more frequent. The
OPR is prepared by performing the preparation steps given in Sections 8.4.4.1 -
8.4.4.6 on the OPR standard (Section 7.4.7). Do not utilize the procedures in Section
8.3 to process the OPR through the 0.45 /xm filter (Section 6.14.1), even if samples
are being collected for dissolved metals determinations.
9.6.3 MS/MSD—The sampling team must prepare one MS and one MSD for every ten field
samples, or one per sample set, whichever is more frequent.
24 December 1994
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Method 1669
9.6.3.1 If through historical data, the background concentration of the sample
can be estimated, the MS and MSD samples should be spiked at a
level of 2 to 5 times the background concentration.
9.6.3.2 For samples where the background concentration is unknown, the MS
and MSD samples should be spiked at a concentration of 25 fig/L.
9.6.3.3 Prepare the matrix spike sample by taking a 100-mL aliquot of
sample, spiking it with 2.5 mL of the standard chromium spike
solution (Section 7.4.6), and processing it through the sample
preparation steps given in Sections 8.4.4.1 - 8.4.4.6.
9.6.3.4 Prepare the matrix spike duplicate sample by taking a second 100-mL
aliquot of the same sample, spiking it with 2.5 mL of the spike
solution, and processing it through the preparation steps given in
Sections 8.4.4.1 - 8.4.4.6. '_
9.6.3.5 If field samples are collected for dissolved metals determinations, it is
necessary to process an MS and an MSD aliquot through the 0.45
filter as described in Section 8.3.
10.0 RE-CLEANING THE APPARATUS BETWEEN SAMPLES
10.1 Sampling activity should be planned so that samples known or suspected to contain the lowest
concentrations of trace metals are collected first with the samples known or suspected to
contain the highest concentrations of trace metals collected last. In this manner, cleaning of
the sampling equipment between samples in unnecessary.
10.2 If samples are collected from adjacent sites (e.g., immediately upstream or downstream),
rinsing of the sampling Apparatus with water that is to be sampled should be sufficient.
i
10.3 If it is necessary to cross a gradient (i.e., going from a high concentration sample back to a
low concentration sample), such as might occur when collecting at a second site, then the
following procedure may be used to clean the sampling equipment between samples:
10.3.1 In the glove bag, and using the "clean hands/dirty hands" procedure in Section 8.2.5,
process the dilute nitric acid solution (Section 7.2) through the Apparatus.
10.3.2 Dump the spent dilute acid in the waste carboy or in the water body away from the
sampling point.
10.3.3 Process one liter of reagent water through the Apparatus to rinse the equipment and
discard the spent water.
10.3.4 Collect a field blank as described in Section 9.4.
10.3.5 Rinse the Apparatus with copious amounts of the ambient water sample and proceed
with sample collection.
December 1994 , 25
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Method 1669
10.4 Procedures for re-cleaning trivalent chromium preservation equipment between samples are
described in Section 8.4.4.
11.0 METHOD PERFORMANCE
Samples were collected in the Great Lakes during the September - October 1994 period using
the procedures in this sampling method. Performance data from this and other activities will
be added when testing is completed.
12.0 POLLUTION PREVENTION
12.1 The only materials used in this procedure that could be considered pollutants are the acids
used in the cleaning of the Apparatus, the boat, and related materials. These acids are used in
dilute solutions in small amounts and pose little threat to the environment when managed
properly.
12.2 Cleaning solutions containing acids should be prepared in volumes consistent with use to
minimize the disposal of excessive volumes of acid.
13.0 WASTE MANAGEMENT
13.1 It is the sampling team's responsibility to comply with all,federal, state, and local regulations
governing waste management, particularly the discharge regulations, hazardous waste
identification rules, and land disposal restrictions; and to protect the air, water, and land by
minimizing and controlling all releases from field operations.
13.2 The acidic solutions shipped in samples are at pH 2 - 3 and are therefore not classified as
hazardous materials. These solutions may be disposed in the water body being sampled well
away from the sampling point with no risk to the environment.
13.3 For further information on waste management, consult "The Waste Management Manual for
Laboratory Personnel" and "Less is Better—Laboratory Chemical Management for Waste
Reduction," available from the American Chemical Society's Department of Government
Relations and Science Policy, 1155 16th Street N.W., Washington, D.C. 20036.
14.0 REFERENCES
14.1 Adeloju, S.B.; Bond, A.M., "Influence of Laboratory Environment on the Precision and
Accuracy of Trace Element Analysis", Anal. Chem. 1985, 57, 1728.
14.2 Berman, S.S.; Yeats, P.A., "Sampling of Seawater for Trace Metals", in CRCReviews in
Analytical Chemistry 1985, 16.
26 . December 1994
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Method 1669
14.3 Bloom, N.S. "Ultra-Clean Sampling, Storage, and Analytical Strategies for the Accurate
Determination of Trace Metals in Natural Waters", presented at the 16th Annual EPA
Conference on the Analysis of Pollutants in the Environment, Norfolk, Virginia, May 5,
• 1993.
14.4 Bruland, K.W., "Trace Elements in Seawater," Chemical Oceanography 1983, 8, 157.
14.5 Nriagu, J.O.; Larson, G.; Wong, H.K.T.; Azcue, J.M., "A Protocol for Minimizing
Contamination in the Analysis of Trace Metals in Great Lakes Waters" J. Great Lakes
Research 1993, 19, 175.
14.6 Patterson, C.C.; Settle, D.M., "Accuracy in Trace Analysis", in National Bureau of
Standards Special Publication 422\ LaFleur, P.O., Ed., U.S. Government Printing Office,
Washington, DC, 1976.
14.7 "A Protocol for the Collection and Processing of Surface-Water Samples for Subsequent
Determination of Trace Elements, Nutrients, and Major Ions in Filtered Water"; Office of
Water Quality Technical Memorandum 94.09, Office of Water Quality, Water Resources
Division, U.S. Geological Survey, Reston, VA, 22092, January 28 1994.
14.8 Standard Operating Procedure No. 4-54, Revision 01, SOP for Concentration and Analysis of
Chromium Species in Whole Seawater, Prepared by Battelle Ocean Sciences, Duxbury, MA
for the U.S. Environmental Protection Agency Office of Marine Environmental Protection,
Ocean Incineration Research Program. 1987.
14.9 Cranston, R.E.; Murray, J.W., "The Determination of Chromium Species in Natural
Waters", Anal. Chem. Acta 1978, 99, 275.
14.10 Prothrd, Martha G. "Office of Water Policy and Technical Guidance on Interpretation and
Implementation of Aquatic Life Metals Criteria", EPA Memorandum to Regional Water
Management and Environmental Services Division Directors, October 1, 1993.
14.11 "Format for Method Documentation", Distributed by the EPA Environmental Monitoring
Management Council, Washington, DC, November 18, 1993.
14.12 Windom, H.L; Byrd, J.T.; Smith, R.G., Jr.; Huan, F., "Inadequacy of NASQAN Data for
Assessing Metal Trends in the Nation's Rivers", Environ. Sci. Technol. 1991, 25, 1137.
14.13 Zief, M.; Mitchell, J.W., "Contamination Control in Trace Metals Analysis" in Chemical
Analysis 1976; Vol. 47 Chapter 6.
14.14 Phillips, H.; Shafer, M.; Dean, P.; Walker, M.; Armstrong, D. "Recommendations for Trace
Metals Analysis of Natural Waters"; Wisconsin Department of Natural Resources: Madison,
WI, May 1992.
14.15 Hunt, C.D. In Manual of Biological and Geochemical Techniques in Coastal Areas; 2nd ed.;
Lambert, C.E. and Oviatt, C.A., Eds.; Marine Ecosystems Research Laboratory; Graduate
School of Oceanography; The University of Rhode Island: Narragansett, RI, MERL Series,
Report No. 1, Chapter IV.
December 1994 27
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Method 1669
14.16 Flegal, Russell, Summer 1994 San Francisco Bay Cruise, apparatus and procedures witnessed
and videotaped by William Telliard and Thomas Fieldsend, September 15 - 16, 1994.
14.17, Watras, Carl, Wisconsin DNR procedures for mercury sampling in pristine lakes in
Wisconsin, witnessed and videotaped by Dale Rushneck and Lynn Riddick, September 9 - 10,
1994.
14.18 Horowitz, Arthur J., Kent A. Elrick, and Mark R. Colberg, "The Effect of Membrane
Filtration Artifacts on Dissolved Trace Element Concentrations" 1992, Wat. Res. 26, 753.
14.19 Engineering Support Branch Standard Operating Procedures and Quality Assurance Manual:
1986; U.S. Environmental Protection Agency. Region IV. Environmental Services Division:
Athens, Georgia.
14.20 Grohse, Peter, Research Triangle Institute, Institute Drive, Building 6, Research Triangle
. Park, NC 27709.
14.21 Methods 1624 and 1625, 40-CFR Part 136, Appendix A.
15.0 GLOSSARY OF DEFINITIONS AND PURPOSES
These definitions and purposes are specific to this sampling method but have been conformed
to common usage as much as possible.
15.1 Apparatus — The sample container and other containers, filters, filter holders, labware,
tubing, pipettes, and other materials and devices used for sample collection or sample
preparation, and that will contact samples, blanks, or analytical standards.
15.2 Equipment blank — An aliquot of reagent water that is subjected in the laboratory to all
aspects of sample collection and analysis, including contact with all sampling devices and
apparatus. The purpose of the equipment blank is determine if the sampling devices and
apparatus for sample collection have been adequately cleaned prior to shipment to the field
site. An acceptable equipment blank must be achieved before the sampling devices and
apparatus are used for sample collection.
15.3 Field blank — An aliquot of reagent water that is placed in a sample container in the
laboratory, shipped to the field, and treated as a sample in all respects, including contact with
the sampling devices and exposure to sampling site conditions, filtration, storage,
preservation, and all analytical procedures. The purpose of the field blank is to determine if
the field or sample transporting procedures and environments have contaminated the sample.
15.4 Field duplicates (FD1 and FD2) — Two identical aliquots of a sample collected in separate
sample bottles at the same time and place under identical circumstances using a duel inlet
sampler or by splitting a larger aliquot and treated exactly the same throughout field and
laboratory procedures. Analyses of FD1 and FD2 give a measure of the precision associated
with sample collection, preservation, and storage, as well as with laboratory procedures.
28 - December 1994
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Method 1669
14.3 Bloom, N.S. "Ultra^Clean Sampling, Storage, and Analytical Strategies for the Accurate
Determination of Trace Metals in Natural Waters", presented at the 16th Annual EPA
Conference on the Analysis of Pollutants in the Environment, Norfolk, Virginia, May 5,
• 1993. ...
14.4 Bruland, K.W., "Trace Elements in Seawater," Chemical Oceanography 1983, 8, 157.
14.5 Nriagu, J.O.; Larson, G.; Wong, H.K.T.; Azcue, J.M., "A Protocol for Minimizing
Contamination in the Analysis of Trace Metals in Great Lakes Waters" J. Great Lakes
Research 1993, 19, 175.
14.6 Patterson, C.C.; Settle, D.M., "Accuracy in Trace Analysis", in National Bureau of
Standards Special Publication422; LaFleur, P.O., Ed., U.S. Government Printing Office,
Washington, DC, 1976.
14.7 "A Protocol for the Collection and Processing of Surface-Water Samples for Subsequent
Determination of Trace Elements, Nutrients, and Major Ions in Filtered Water"; Office of
Water Quality Technical Memorandum 94.09, Office of Water Quality, Water Resources
Division, U.S. Geological Survey, Reston, VA, 22092, January 28 1994:
14.8 Standard Operating Procedure No. 4-54, Revision 01, SOP for Concentration and Analysis of
Chromium Species in Whole Seawater, Prepared by Battelle Ocean Sciences, Duxbury, MA
for the U.S. Environmental Protection Agency Office of Marine Environmental Protection,
Ocean Incineration Research Program. 1987.
14.9 Cranston, R.E.; Murray, J.W., "The Determination of Chromium Species in Natural
Waters", Anal. Chem. Ada 1978, 99, 275. •
14.10 Prothrd, Martha G. "Office of Water Policy and Technical Guidance on Interpretation and
Implementation of Aquatic Life Metals Criteria", EPA Memorandum to Regional Water
Management and Environmental Services Division Directors, October 1, 1993.
14.11 "Format for Method Documentation", Distributed by the EPA Environmental Monitoring
Management Council, Washington, DC, November 18, 1993.
14.12 Windom, H.L; Byrd, J.T.; Smith, R.G., Jr.; Huan, F., "Inadequacy of NASQAN Data for
Assessing Metal Trends in the Nation's Rivers", Environ. Sci. Technol. 1991, 25, 1137.
14.13 Zief, M.; Mitchell, J.W., "Contamination Control in Trace Metals Analysis" in Chemical
Analysis 1976; Vol. 47 Chapter 6.
14.14 Phillips, H.; Shafer, M.; Dean, P.; Walker, M.; Armstrong, D. "Recommendations for Trace
Metals Analysis of Natural Waters"; Wisconsin Department of Natural Resources: Madison,
WI, May 1992.
14.15 Hunt, C.D. In Manual of Biological and Geochemical Techniques in Coastal Areas; 2nd ed.;
Lambert, C.E. and Oviatt, C.A., Eds.; Marine Ecosystems Research Laboratory; Graduate
School of Oceanography; The University of Rhode Island: Narragansett, RI, MERL Series,
Report No. 1, Chapter IV.
December 1994 27
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Method 1669
14.16 Flegal, Russell, Summer 1994 San Francisco Bay Cruise, apparatus and procedures witnessed
and videotaped by William Telliard and Thomas Fieldsend, September 15 - 16, 1994.
14.17 Watras, Carl, Wisconsin DNR procedures for mercury sampling in pristine lakes in
Wisconsin, witnessed and videotaped by Dale Rushneck and Lynn Riddick, September 9 - 10,
1994.
14.18 Horowitz, Arthur J., Kent A. Elrick, and Mark R. Colberg, "The Effect of Membrane
Filtration Artifacts on Dissolved Trace Element Concentrations" 1992, Wat. Res. 26, 753.
14.19 Engineering Support Branch Standard Operating Procedures and Quality Assurance Manual:
1986; U.S. Environmental Protection Agency. Region IV. Environmental Services Division:
Athens, Georgia.
14.20 Grohse, Peter, Research Triangle Institute, Institute Drive, Building 6, Research Triangle
Park, NC 27709.
14.21 Methods 1624 and 1625, 40 CFR Part 136, Appendix A.
15.0 GLOSSARY OF DEFINITIONS AND PURPOSES
These definitions and purposes are specific to this sampling method but have been conformed
to common usage as much as possible.
15.1 Apparatus — The sample container and other containers, filters, filter holders, labware,
tubing, pipettes, and other materials and devices used for sample collection or sample
preparation, and that will contact samples, blanks, or analytical standards.
15.2 Equipment blank — An aliquot of reagent water that is subjected in the laboratory to all
aspects of sample collection and analysis, including contact with all sampling devices and
apparatus. The purpose of the equipment blank is determine if the sampling devices and
apparatus for sample collection have been adequately cleaned prior to shipment to the field
site. An acceptable equipment blank must be achieved before the sampling devices and
apparatus are used for sample collection.
15.3 Field blank — An aliquot of reagent water that is placed in a sample container in the
laboratory, shipped to the field, and treated as a sample in all respects, including contact with
the sampling devices and exposure to sampling site conditions, filtration, storage,
preservation, and all analytical procedures. The purpose of the field blank is to determine if
the field or sample transporting procedures and environments have contaminated the sample.
15.4 Field duplicates (FD1 and FD2) — Two identical aliquots of a sample collected in separate
sample bottles at the same time and place under identical circumstances using a duel inlet
sampler or by splitting a larger aliquot and treated exactly the same throughout field and
laboratory procedures. Analyses of FD1 and FD2 give a measure of the precision associated
with sample collection, preservation, and storage, as well as with laboratory procedures.
28 December 1994
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Method 1669
15.5 Matrix spike (MS) and matrix spike duplicate (MSD) — Aliquots of an environmental sample
to which known quantities of the analytes are added in the laboratory. The MS and MSD are
analyzed exactly like a sample. Their purpose is to quantify the bias and precision caused by
' the sample matrix. The background concentrations of the analytes in the sample matrix must
be determined in a separate aliquot and the measured values in the MS and MSD corrected for
background concentrations.
15.6 May — This action, activity, or procedural step is neither required nor prohibited.
15.7 May not — This action, activity, or procedural step is prohibited.
15.8 Minimum level (ML) — The lowest level at which the entire analytical system gives a
recognizable signal and acceptable calibration point (Reference 14.21)
15.9 Must — This action, activity, or procedural step is required.
15.10 Reagent water — Water demonstrated to be free from the metal(s) of interest and potentially
interfering substances at the MDL for that metal in the Referenced Method or Additional
Method.
15.12 Should — This action, activity, or procedural step is suggested but not required.
15.13 Trace-metal grade — Reagents which have been demonstrated to be free from the metal(s) of
interest at the method detection limit (MDL) of the analytical method to be used for
determination of this metal(s).
Note: the term "trace-metal grade" has been used in place of "reagent grade" or "reagent"
because acids and other materials labeled "reagent grade" have been shown to contain
concentrations of metals that will interfere in the determination of trace metals at ambient
water quality criteria levels.
December 1994 29
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Table 1
List of Analytes Amenable to Collection Using Method 1669: Lowest Water Quality Criterion for Each
Metal Species, Applicable EPA Methods, Analytical Techniques, Method Detection Limits, and Minimum
Levels for the EPA Methods
Key:
Notes:
1.
2.
3.
Metal
Antimony
Arsenic
Cadmium
Chromium (III)
Chromium (VI)
Copper
Lead
Mercury
Nickel
Selenium
Silver
Thallium
Zinc
' Lowest EPA
Water Quality
Criterion
0«g/L)'
14
0.018
0.32
57
10.5
2.5
0.14
0.012
7.1
5
0.31
1.7
28
EPA Method, analytical technique, and MDL/ML in pg/L
Method
200.8
200.9
—
200.8
200.9
200.10
200.13
...
218.6
200.8
200.10
200.8
200.10
200.13
—
200.8
200.9
200.10
200.8
200.9
200.8
200.8
200.8
200.9
Technique
ICP/MS
STGFAA
-,-'-
ICP/MS
STGFAA
CC/ICP/MS
CC/STGFAA
—
Ion Chrom.
ICP/MS
CC/ICP/MS
ICP/MS
CC/ICP/MS
CC/STGFAA
'
ICP/MS
STGFAA
CC/ICP/MS
ICP/MS
STGFAA
ICP/MS
ICP/MS
ICP/MS
STGFAA
MDL2
0.007
0.34
—
0.025
0.013
0.00094
0.0029
...
0.23
0.043
0.0083
.0.015
0.0039
0.012
—
0.33
0.65
0.013
1.2
0.69
0.018
0.007
0.069
0.10
ML1
0.02
1
—
O.I
0.05
0.002
0.01
—
0.5
0.1
0.02
0.05
0.01
0.05
—
1
2
0.05
5
2
0.05
0.02
0.2
0.2
ICP = Inductively coupled plasma Ion chrom
AES = Atomic emission spectrometry CC
MS = Mass spectrometry • CVAF
GFAA = Graphite furnace atomic absorption spectrometry • STGFAA
Ion chromatography
Chelation/concentration
Cold vapor atomic fluorescence
Stabilized temperature GFAA
Lowest of the freshwater, marine, and human health WQC promulgated by EPA for 14 states at 40 CFR Part 131 (57 FR 60848),
with hard ness-dependent freshwater aquatic life criteria adjusted in accordance with 57 FR 60848 to reflect the worst case hardness
of 25 mg/L CaCO) and all aquatic life criteria adjusted in accordance with the 10/1/93 Office of Water guidance to reflect dissolved
metals criteria. A complete listing of all WQC, including total, dissolved, and levels calculated with a hardness of 25 mg/L CaCO,
and a hardness of 100 mg/L CaCO, is provided in Appendix A:
Method Detection Limit as determined by 40 CFR Part 136; Appendix B.
Minimum Level (ML) calculated by multiplying laboratory-determined MDL by 3.18 and rounding result to nearest multiple of 1,
2, 5, 10, 20, 50 etc. in accordance with procedures utilized by EAD and described in the EPA Draft National Guidance for the
Permitting, Monitoring, and Enforcement of Water Quality-Based Effluent Limitations Set Below Analytical Detection/Quantitation
Levels, March 22, 1994.
30
December 1994
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Figure 1 • Grab Sampling Device
Teflon Sealing
Mechanism —.
Tenon
Pull Cord
500 ml*
Teflon
Bottle
31
-------
Figure 2 - Grab Sampling Device
2.5cm PVC ROD
1
5.1 cm
PVC PIPE
PVC ROD
T
46cm
1
PVC
PLATE
IBcni
H8cnH
32
-------
Figure 3 • Jar Sampling Device
Support
(Ttflon)
\
Teflon
Support
PUU
1/4' Tubing
T« Surftct
Pump
(Ttflon)
I L T«flon
/•r
Ttflon Torptdo
Vttiht
33
-------
Figure 4 - Sample Pumping System
Teflon
Tubing
Fiberglass
Pole
Cable Ties
Peristaltic
C-Flex Pump
Tubing
Tubing
Adaptor
Filter
Cartridge
Clamp
Ring Stand
Teflon Weight
34
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SECTION 3
Quality Control Supplement for Determination of
Trace Metals at EPA Water Quality Criteria
Levels Using EPA Metals Methods
EPA Office of Water, Engineering & Analysis Division
-------
Quality Control Supplement for Determination of Trace Metals at EPA
Water Quality Criteria Levels Using EPA Metals Methods
December 1994
U.S. Environmental Protection Agency
Office of Water
Office of Science and Technology
Engineering and Analysis Division (4303)
401 M St. SW
Washington, DC 20460
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QC Supplement for Determination of Trace Metals at EPA WQC'Levels
Acknowledgements
This quality control (QC) supplement was prepared under the direction of William A. Telliard of the U.S.
Environmental Agency's (EPA's) Office of Water (OW), Engineering and Analysis Division (EAD). The
supplement was prepared under EPA Contract 68-C3-0337 by the Environmental Programs Division of
DynCorp Environmental, with the assistance of Interface, Inc.
The following researchers in marine chemistry contributed to the philosophy behind this supplement.
Their contribution is gratefully acknowledged:
Shier Berman, National Research Council, Ottawa, Ontario, Canada;
Nicholas Bloom, Frontier Geosciences Inc, Seattle, Washington;
Paul Boothe and Gary Steinmetz, Texas A&M University, College State, Texas;
Eric Crecelius, Battelle Marine Sciences Laboratory, Sequim, Washington;
Russell Flegal, University of California/Santa Cruz, California;
Gary Gill, Texas A&M University at Galveston, Texas;
Carlton Hunt and Dion Lewis, Battelle Ocean Sciences, Duxbury, Massachusetts;
Carl Watras, Wisconsin Department of Natural Resources, Boulder Junction, Wisconsin; and
Herb Windom and Ralph Smith, Skidaway Institute of Oceanography, Savannah, Georgia.
Additional support was provided by Ted Martin of the EPA Office of Research and Development's
Environmental Monitoring Systems Laboratory in Cincinnati, Ohio.
Disclaimer
This supplement has been reviewed and approved for publication by the Engineering and Analysis
Division of the U.S. Environmental Protection Agency. Mention of trade names or commercial products
does not constitute endorsement or recommendation for use.
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QC Supplement for Determination of Trace Metals at EPA WQC Levels
1.0 SCOPE AND APPLICATION
1.1 This document (hereinafter referred to as the "QC Supplement") is designed to aid in the
determination of metals at EPA water quality criteria (WQC) levels using the EPA methods listed
in Section 1.2 below. Use of these EPA methods to determine metals at EPA WQC levels
requires the use of stringent quality control (QC) procedures to avoid contamination and ensure
the validity of analytical results during sampling and analysis. Therefore, this QC Supplement
describes the QC procedures necessary to assure that contamination will be detected when blanks
that accompany samples are analyzed. This QC Supplement is accompanied by Method 1669:
Sampling Ambient Water for Determination of Trace Metals at EPA Water Quality Criteria Levels
(hereinafter referred to as the "Sampling Method"). The Sampling Method is necessary to assure
that trace metals determinations will not be compromised by contamination during the sampling
process.
1.2 The increased QC procedures described in this QC Supplement are applicable to the following
EPA methods and method compendium* (hereinafter referred to as the "Referenced Methods"):
1.2.1 Five methods documented in Methods for the Determination of Metals in Environmental
Samples (EPA/600/4-91/010), revised June 1991; available from the National Technical
Information Service (NTIS), Springfield, VA 22161, 800-553-6847, as publication
number PB 92-231498. These five methods are:
1.2.1.1 Method 200.7 Metals in Water by ICP/AES
1.2.1.2 Method 200.8 Metals in Water by ICP/MS
1.2.1.3 Method 200.9 Metals in Water by STGFAA
1.2.1.4 Method 200.10 Metals in Water by Chelation/Concentration ICP/MS
1.2.1.4 Method 218.6 Hexavalent Chromium in Water by Ion Chromatography
1.2.2 Two methods documented in Methods for the Determination of Chemical Substances in
Marine and Estuarine Environmental Samples (EPA/600/R-92/121), November 1993,
NTIS PB 93-182913. These two methods are:
1.2.2.1 Method 200.10 Metals in Water by Chelation/Concentration ICP/MS
1.2.2.2 Method 200.13 Metals in Marine Water by Chelation/Concentration
GFAA
1.3 The Referenced Methods are not included in this QC Supplement.
1.4 This QC Supplement is required for use with the Referenced Methods when analyzing water
samples at EPA WQC levels for dissolved metals. Table 1 lists the Referenced Methods that
achieve or most closely approach EPA WQC levels, the Method Detection Limit (MDL) for each
metal, and the Minimum Level (ML, see Section 2.3) set for each metal in these methods.
Additional methods have been developed specifically for determination of metals not covered by
the Referenced Methods. These additional methods contain integral QC required for
determination of metals at WQC levels.
1.5 This QC Supplement is not intended for determination of metals at concentrations normally found
in treated and untreated discharges from industrial facilities. Existing regulations (40 CFR Parts
400 - 500) typically limit concentrations in industrial discharges to the mid to high part-per-billion
December 1994 l
I 7 7
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QC Supplement for Determination of Trace Metals at EPA WQC Levels
(ppb) range, whereas ambient metals concentrations are normally in the low part-per-trillion (ppt)
to low ppb range.
1.6 • The ease of contaminating ambient water samples with the metal(s) of interest and interfering
substances cannot be overemphasized. This QC Supplement includes suggestions for
improvements in facilities and analytical techniques that should maximize the ability of the
laboratory to make reliable trace metals determinations and minimize contamination. These
suggestions are given in Section 4.0 "Contamination and Interferences" and are based on findings
of researchers performing trace metals analyses (References 17.1 - 17.6).
1.7 Clean and Ultra-clean-The terms "Clean" and "Ultra-clean" have been applied to the techniques
needed to reduce or eliminate contamination in trace metals determinations. These terms are not
used in this QC Supplement because of their lack of an exact definition. However, the
information provided in this QC Supplement is consistent with and copied from summary
guidance on Clean and Ultra-clean techniques (Reference 17.7)..
1.8 This QC Supplement follows the EPA Environmental Methods Management Council's "Format
for Method Documentation" (Reference 17.8), and is therefore consistent with the Referenced
Methods and the additional methods described in Section 1.4. Where appropriate, sections of the
Referenced Methods have been expanded by this QC Supplement to include the increased
operational procedures and QC necessary for determination of trace metals at EPA WQC levels.
In these instances, the procedures and QC in this QC Supplement take precedence over the
procedures and QC in the Referenced Methods; otherwise, all procedures and QC in the
Referenced Methods must be followed.
1.9 This QC Supplement is "performance-based"; i.e., an alternate procedure or technique may be
used, as long as the performance requirements in the Referenced Methods and this QC
Supplement are met. Section 9.1.2 gives details of the tests and documentation required to
support equivalent performance.
1.10 For dissolved metal determinations, samples must be filtered through a 0.45 /*m capsule filter at
the field site. The filtering procedures are described in the Sampling Method. The filtered
samples may be preserved in the field or transported to the laboratory for preservation.
Procedures for field preservation are detailed in the Sampling Method; procedures for laboratory
preservation are provided in this QC Supplement.
1.11 The procedures in this QC Supplement are for use only by personnel thoroughly trained in the
handling and analysis of samples for determination of metals at EPA WQC levels.
2.0 SUMMARY OF QC SUPPLEMENT
2.1 Expanded and standardized QC—The QC in each Referenced Method is expanded and
standardized by this QC Supplement to include: tests of calibration linearity and calibration
verification; demonstration of initial precision and recovery; demonstration of ongoing precision
and recovery; analysis of matrix spike and matrix spike duplicate samples; and analysis of blanks.
QC acceptance criteria for each test are also included in this document. This standardized QC
was developed in conjunction with the development of a data review guidance document being
generated to support verification and validation of WQC data. The data review guidance
December 1994
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QC Supplement for Determination of Trace Metals at EPA WQC Levels
document will be titled Method for Review of Trace Metals Data Generated Using EPA Metals
Methods (hereinafter referred to as the Data Review Method).
2.2 ' Revised QC limits—QC acceptance criteria in the Referenced Methods have been revised in this
QC Supplement to reflect measurements at low levels and to make these criteria more realistic
than those given in the Referenced Methods. The acceptance criteria were revised using a simple
analysis of variance (ANOVA) statistic. The revised criteria, which were verified in a single-
laboratory study, are presented in Table 2.
2.3 Development of Minimum Levels (MLs)—The ML is "the lowest level at which the entire
analytical system gives a recognizable signal and acceptable calibration point" (Reference 17.9).
In principle, the ML is identical to the American Chemical Society (ACS) limit of quantitation
(LOQ; Reference 17.10). The ML is developed by multiplying the EPA 7-replicate MDL (40
CFR 136, Appendix B) by 3.18 to achieve the ACS LOQ. The resulting exact number is then
rounded to allow its use in instrument calibration. Calibration at the ML is required in every
laboratory practicing this QC Supplement to support WQC metals measurements (Section 10.1).
Minimum levels for the metals are given in Table 1. Laboratories making trace metals
measurements using the Referenced Methods and this QC Supplement must calibrate the
instrument at the ML prior to proceeding with analysis, thus demonstrating that the ML can be
achieved and proving that trace metals measurements can be made at the ML.
3.0 DEFINITIONS
3.1 Apparatus-Throughout this QC Supplement, the sample containers, sampling devices,
instrumentation, and all other materials and devices used in sample collection, sample processing,
and sample analysis activities will be referred to collectively as the Apparatus.
3.2 Other definitions of terms are given in the Glossary (Section 18) at the end of this QC
Supplement.
4.0 CONTAMINATION AND INTERFERENCES
4.1 Preventing ambient water samples from becoming contaminated during the sampling and
analytical process constitutes one of the greatest difficulties encountered with trace metals
determinations. Over the last two decades, marine chemists have come to recognize that much
of the historical data regarding the concentrations of dissolved trace metals in seawater are
erroneously high because the concentrations reflect contamination from sampling and analysis
rather than ambient levels. More recently, historical trace metals data collected from freshwater
rivers and streams have been shown to be similarly biased due to contamination during sampling
and analysis (Reference 17.11). Therefore, it is imperative that extreme care be taken to avoid
contamination when collecting and analyzing ambient water samples for trace metals.
".2 There are numerous routes by which samples may become contaminated. Potential sources of
trace metals contamination during sampling include: metallic or metal-containing labware (e.g.,
talc gloves which contain high levels of zinc), containers, sampling equipment, reagents, and
reagent water; improperly cleaned and stored equipment, labware, and reagents; and atmospheric
inputs such as dirt and dust. Even human contact can be a source of trace metals contamination.
December 1994
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QC Supplement for Determination of Trace Metals at EPA WQC Levels
For example, it has been demonstrated that dental work (e.g. mercury amalgam fillings) in the
mouths of laboratory personnel can contaminate samples that are directly exposed to exhalation
(Reference 3).
9
4.3 Contamination Control .
4.3.1 Philosophy—The philosophy behind contamination control is to ensure that any object or
substance that contacts the sample is metal free and free from any material which may
contain metals.
4.3.1.1 The integrity of the results produced cannot be compromised by
contamination of samples. Requirements and suggestions for control of
sample contamination are given in this QC Supplement, the Sampling
Method, and the Referenced Methods.
4.3.1.2 Substances in a sample cannot be allowed to contaminate the laboratory
work area or instrumentation used for trace metals measurements.
Requirements and suggestions for protecting the laboratory are given in
this QC Supplement.
4.3.1.3 While contamination control is essential, personnel health and safety
remain the highest priority. Requirements and suggestions for personnel
safety are given in Sections 5 of this QC Supplement, the Sampling
Method, and the Referenced Methods.
4.3.2 Avoiding contamination—The best way to control contamination is to completely avoid
exposure of the sample to contamination in the first place. Avoiding exposure means
performing operations in an area known or thought to be free from contamination. Two
of the most important factors in avoiding/reducing sample contamination are: (1) an
awareness of potential sources of contamination and (2) strict attention to work being
done. Therefore it is imperative that the procedures described in the Referenced Methods
and this QC Supplement be carried out by well-trained, experienced personnel.
4.2.3.1 Use a clean environment~The ideal environment for processing samples
is a class-100 clean room (Section 6.1.1). If a clean room is not
available, all sample preparation must be performed in a class-100 clean
bench or a non-metal glove box fed by particle-free air or nitrogen.
Digestions must be performed in a non-metal fume hood, ideally situated
in the clean room.
4.3.2.2 Minimize exposure—The Apparatus that will contact samples, blanks, or
standard solutions must only be opened or exposed in a clean room,
clean bench, or glove box so that exposure to an uncontrolled atmosphere
is minimized. When not being used, the Apparatus should be covered
with clean plastic wrap, stored in the clean bench or in a plastic box or
glove box, or bagged in clean zip-type bags. Minimizing the time
. between cleaning and use will also minimize contamination.
December 1994
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QC Supplement for Determination of Trace Metals at EPA WQC Levels
4.3.2.3 Clean work surfaces-Prior to processing a given batch of samples, all
work surfaces in the hood, clean bench, or glove box in which the
samples will be processed should be cleaned by wiping with a lint-free
" • cloth or wipe soaked with reagent water.
4.3.2.4 Wear gloves-Sampling personnel must wear clean, non-talc gloves
(Section 6.2.4) during all operations involving handling of the Apparatus,
samples, and blanks. Only clean gloves may touch the Apparatus. If
another object or substance is touched, the glove(s) must be changed
before again handling the Apparatus. If it is even suspected that gloves
have become contaminated, work must be halted, the contaminated
gloves removed, and a new pair of clean gloves put on. Wearing
multiple layers of clean gloves will allow the old pair to be quickly
stripped with minimal disruption to the work activity.
4.3.2.5 Use metal-free Apparatus-All Apparatus used for metals determinations
at ambient water quality criteria levels must be non-metallic and/or free
of material that may contain metals.
4.3.2.5.1 Construction materials—Only the following materials
should come in contact with samples: fluoropolymer
(FEP, PTFE), conventional or linear polyethylene,
polycarbonate, polypropylene, polysulfone, or ultra-pure
quartz. PTFE is less desirable than FEP because the
sintered material in PTFE may contain contaminates and
is susceptible to serious memory contamination
(Reference 17.6). Only fluoropolymer should be used
for samples that will be analyzed for mercury because
mercury vapors can diffuse in or out of the other
materials resulting either in contamination or low-biased
results (Reference 17.3). Glass and metal must not be
used under any circumstance. All materials regardless
of construction that will directly or indirectly contact the
sample must be cleaned using the procedures described
in Section 11 and must be known to be clean and metal-
free before proceeding.
4.3.2.5.2 The following materials have been found to contain trace
metals and must not be used to hold liquids that come in
contact with the sample or must not contact the sample
itself, unless these materials have been shown to be free
of the metals of interest at the desired level: Pyrex,
Kimax, methacrylate, polyvinylchloride, nylon, and
Vycor (Reference 17.6). In addition, highly colored
plastics, paper cap liners, pigments used to mark
increments on plastics, and rubber all contain trace levels
of metals and must be avoided (Reference 17.10).
December 1994 5
3'
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QC Supplement for Determination of Trace Metals at EPA WQC Levels
4.3.2.5.3 Serialization—Serial numbers should be indelibly marked
or etched on each piece of Apparatus so that
contamination can be traced, and logbooks should be
maintained to track the sample from the container
through the labware to injection into the instrument. It
may be useful to dedicate separate sets of labware to
different sample types; e.g., receiving waters vs.
effluents. However, the Apparatus used for processing
blanks and standards must be mixed with the Apparatus
used to process samples so that contamination of all
labware can be detected.
4.3.2.5.4 The laboratory or cleaning facility is responsible for
cleaning the Apparatus used by the sampling team. If
there are any indications that the Apparatus is not clean
when received by. the sampling team (e.g., ripped
storage bags), an assessment of the likelihood of
contamination must be made. Sampling must not
proceed if it is possible that the Apparatus is
contaminated. If the Apparatus is contaminated, it must
be returned to the laboratory or cleaning facility for
proper cleaning before any sampling activity resumes.
4.3.2.6 Avoid Sources of Contamination-Avoid contamination by being aware
of potential sources and routes of contamination.
4.3.2.6.1 Contamination by carry-over—Contamination may occur
when a sample containing low concentrations of metals
is processed immediately after a sample containing
relatively high concentrations of these metals. To reduce
carry-over, the sample introduction system may be
rinsed between samples with dilute acid and reagent
water. When an unusually concentrated sample is
encountered, it is followed by analysis of a laboratory
blank to check for carry-over. For samples containing
high levels of metals, it may be necessary to acid clean
or replace the connecting tubing or inlet system to assure
that contamination will not affect subsequent
measurements. Samples known or suspected to contain
the lowest concentration of metals should be analyzed
first followed by samples containing higher levels. For
instruments containing autosamplers, the laboratory
should keep track of which station is used for a given
sample. When an unusually high concentration of a
metal is detected in a sample, the station used for that
sample should be cleaned more thoroughly to prevent
contamination of subsequent samples, and the results for
subsequent samples should be checked for evidence of
the metal(s) that occurred in high concentration.
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4.3.2.6.2 Contamination by samples—Significant laboratory or
instrument contamination may result when untreated
effluents, in-process waters, landfill leachates, and other
samples containing High concentrations of inorganic
substances are processed and analyzed. As stated in
Section 1.0, this QC Supplement is not intended for
application to these samples, and samples containing
high concentrations (> ~ 10 /tg/L) should not be
permitted into the clean room and laboratory dedicated
for processing trace metals samples.
4.3.2.6.3 Contamination by indirect contact—Apparatus that may
not directly come in contact with the samples may still
be a source of contamination. For example, clean tubing
placed in a dirty plastic bag may pick up contamination
from the bag and then subsequently transfer the
contamination to the sample. Therefore, it is imperative
that every piece of the Apparatus that is directly or
indirectly used in the collection, processing, and analysis
of ambient water samples be cleaned as specified in
Section 11.
4.3.2.6.4 Contamination by airborne paniculate matter—Less
obvious substances capable of contaminating samples
include airborne particles. Samples may be
contaminated by airborne dust, dirt, particles, or vapors
from: unfiltered air supplies; nearby corroded or rusted
pipes, wires, or other fixtures; metal-containing paint;
and even human breath (Section 4.2). Whenever
possible, sample processing and analysis should occur as
far as possible from sources of airborne contamination.
4.4 Interferences
4.4.1 Section 4 of each of the Referenced Methods describes the types and nature of
interferences that may be encountered. However, as the concentration of the metal(s)
being determined decreases, the effects of interferences increase. Therefore, more
extensive sample preparation steps, such as chelation/extraction or ion exchange
chromatography, may be necessary to separate the analyte of interest from interferences
when determining metals at the levels for which this QC Supplement is intended.
4.4.2 Interferences resulting from samples will vary considerably from source to source,
depending on the diversity of the site being sampled. If a sample is suspected of
containing substances that may interfere in the determination of trace metals, sufficient
sample should be collected to allow the laboratory to identify and overcome interference
problems.
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5.0 SAFETY
The toxicity or carcinogenicity of the chemicals used in this QC Supplement has not been
- precisely determined; however, these chemicals should be treated as a potential health hazard.
Exposure should be reduced to the lowest possible level. Laboratories are responsible for
maintaining a current awareness file of OSHA regulations regarding the safe handling of the
chemicals specified in this QC Supplement. A reference file of Material Safety Data Sheets
should also be made available to all personnel involved in sample handling and analysis.
6.0 APPARATUS AND EQUIPMENT
Disclaimer: The mention of trade names or commercial products in this QC Supplement is for
illustrative purposes only and does not constitute endorsement or recommendation for use by the
Environmental Protection Agency. Equivalent performance may be achievable using apparatus
and materials other than those suggested here. Demonstration of equivalent performance is the
responsibility of the laboratory.
6.1 Facility
6.1.1 Clean room-class-100, 200 ft2 minimum, with down-flow, positive-pressure ventilation,
air-lock entrances, and pass-through doors.
6.1.1.1 Construction materials-non-metallic, preferably plastic sheeting attached
without metal fasteners. If painted, paints that do not contain the
metal(s) of interest must be used.
6.1.1.2 Adhesive mats, for use at entry points to control dust and dirt from
shoes.
6.1.2 Fume hoods, non-metallic, two minimum, with one installed internal to the clean room.
6.1.3 Clean benches, class-100, one installed in the clean room; the other adjacent to the
analytical instruments) for preparation of samples and standards.
6.2 Labware—All labware must be metal' free. Suitable construction material are fluoropolymer
(FEP, PTFE), conventional or linear polyethylene, polycarbonate, or polypropylene. Only
fluoropolymer should be used when mercury is a target analyte. All labware should be cleaned
per the procedure below (Section 11.4). Gloves, plastic wrap, storage bags, and filters may all
be used new without additional cleaning unless results of the equipment blank pinpoint any of
these materials as a source of contamination. In this case, either an alternate supplier must be
obtained or the materials must be cleaned.
6.2.1 Beakers-50, 100, and 500 mL
6.2.2 Pipets-1.0, 10, and 100 mL
6.2.3 Tongs-For removal of Apparatus from acid baths. Coated metal tongs may not be used.
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6.2.4 Gloves-clean, non-talc polyethylene, latex, or vinyl; various lengths. Heavy gloves
should be worn when working in acid baths since baths will contain hot, strong acids.
6.2.5 Buckets or basins—5 - 50 liter capacity, for acid soaking of the Apparatus.
6.2.6 Non-metallic brushes for scrubbing Apparatus
6.2.7 Storage bags—clean, zip-type, non-vented, colorless polyethylene (various sizes) for
storage of Apparatus
6.2.8 Plastic wrap-clean, colorless polyethylene for storage of Apparatus
6.3 Sampling Equipment—The laboratory or cleaning facility is responsible for cleaning, storing, and
shipping all sampling devices, sample bottles, filtration equipment, and all other Apparatus used
for the collection of ambient water samples. Prior to shipping the equipment to the field site, the
laboratory or facility must generate an acceptable equipment blank (Section 9.5.3) in order to
demonstrate that the sampling equipment is free from contamination.
6.3.1 Sampling Devices-Prior to the collection of ambient water samples, consideration should
be given to the type of sample to be collected and the devices to be used (grab, surface,
or subsurface samplers). The laboratory or cleaning facility must clean all devices used
for sample collection. Various types of samplers are described in the Sampling Method.
Cleaned sampling devices should be stored in polyethylene bags or wrap.
6.3.2 Sample bottles—Fluoropolymer (FEP, PTFE), conventional or linear polyethylene,
polycarbonate, or polypropylene; 500 mL with lids. Cleaned sample bottles should be
filled widi 0.1% HC1 (v/v) until use. Note: If mercury is a target analyte, then
fluoropolymer bottles must be used.
6.3.3 Filtration Apparatus
6.3.3.1 Filters, Gelman Supor 0.45 /xm, 15 mm diameter filter capsules (Gelman
12175), or equivalent
6.3.3.2 Battery-powered peristaltic pump
6.3.3.3 Pump tubing
6.4 Alkaline detergent-Liquinox®, Alconox®, or equivalent
6.5 pH meter or pH paper
7.0 REAGENTS AND STANDARDS
Each reagent lot shall be tested for the metals of interest by diluting and analyzing an aliquot
from the lot using the techniques and instrumentation to be used for analysis of samples. The
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lot will be acceptable if the concentration of the metal of interest is below the MDL of the
Referenced Method or the Additional Method being used.
7.1 ' Reagents for cleaning Apparatus, sample bottle storage, and sample preservation.
7.1.1 Nitric acid (HNO3): Concentrated, Seastar, or equivalent
y
7.1.2 Nitric acid (HNO3): Dilute (1 + 1), Seastar, or equivalent
7.1.3 Nitric acid (HNO3): 10% wt, Seastar, or equivalent
7.1.4 Hydrochloric acid (HC1): 6N trace metal grade ,
7.1.5 Hydrochloric acid (HC1): IN trace metal grade
7.1.6 Hydrochloric acid (HC1): 10% wt, trace metal grade
7.1.7 Hydrochloric acid (HC1): 1 % wt, trace metal grade
7.1.8 Hydrochloric acid (HC1): 0.5% (v/v), trace metal grade (each lot must be pre-analyzed
before use to ensure the acid is free from mercury contamination.)
7.1.9 Hydrochloric acid (HCI): 0.1 % (v/v) ultrapure grade
7.2 Reagent water-water demonstrated to be free from the metal(s) of interest and potentially
interfering substances at the MDL for that metal in the Referenced Method or Additional Method.
Prepared by distillation, deionization, reverse osmosis, anodic/cathodic stripping voltammetry,
or other technique that removes the metal(s) and potential interferent(s).
8.0 SAMPLE COLLECTION, FILTRATION, PRESERVATION, AND STORAGE
8.1 Sample collection—Samples are collected as described in the Sampling Method.
8.2 Sample filtration—For dissolved metals, samples and field blanks are filtered through a 0.45 /im
capsule filter at the field site. Filtering procedures are described in the Sampling Method.
8.3 Sample preservation—Preservation of samples may be performed in the field or in the laboratory.
Field preservation is necessary for determinations of trivalent chromium. It has also been shown
that field preservation with sodium hydroxide can increase sample holding times for hexavalent
chromium to 30 days; therefore it is recommended that preservation of samples for hexavalent
chromium be performed in the field as described in Method 1669. For other metals, however,
the sampling team may prefer to utilize laboratory preservation of samples in order to expedite
field operations and to minimize the potential for sample contamination. Samples and field blanks
should be preserved at the laboratory immediately upon receipt. For all metals except mercury,
preservation involves the addition of 10% HNO3 (Section 7.1.3) to bring the sample to pH <2.
For samples received at neutral pH, approx 5 mL of 10% HNO3 per liter will be required. For
mercury, 0.5% (v/v) HCI (Section 7.1.8) is used as the preservative.
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8.3.1 Wearing clean gloves, remove the cap from the sample bottle, add the volume of reagent
grade acid that will bring the pH to < 2, and re-cap the bottle immediately. If the bottle
is full, withdraw the necessary volume using a pre-cleaned pipet and then add the acid.
Record the volume withdrawn and the amount of acid used.
Note: Do not dip pH paper or a pH meter into the sample; remove a small aliquot with
a clean pipet and test the aliquot.
8.3.2 Store the preserved sample for a minimum of 48 hours at 0 - 4 °C to allow the acid to
completely dissolve the metal(s) adsorbed on the container walls.
8.3.3 With each sample set, preserve a method blank and an OPR sample in the same way as
the sample(s).
8.3.4 Sample bottles should be stored in polyethylene bags at 0 - 4 °C until analysis.
9.0 QUALITY ASSURANCE/QUALITY CONTROL
9.1 Each laboratory that uses this QC Supplement is required to operate a formal quality assurance
program (Reference 17.13). The minimum requirements of this program consist of an initial
demonstration of laboratory capability, analysis of samples spiked with metals of interest to
evaluate and document data quality, and analysis of standards and blanks as tests of continued
performance. Laboratory performance is compared to established performance criteria to
determine if the results of analyses meet the performance characteristics of the method.
9.1.1 The analyst shall make an initial demonstration of the ability to generate acceptable
accuracy and precision with this method. This ability is established as described in
Section 9.2.
9.1.2 In recognition of advances that are occurring in analytical technology, the analyst is
permitted to exercise certain options to eliminate interferences or lower the costs of
measurements. These options include alternate digestion, concentration, and cleanup
procedures, and changes in instrumentation. Alternate determinative techniques, such as
the substitution of a colorimetric technique or changes that degrade method performance,
are not allowed. If an analytical technique other than the techniques specified in the
Referenced Method is used, then that technique must have a specificity equal to or better
than the specificity of the techniques in Referenced Method for the analytes of interest.
9.1.2.1 Each time a modification is made to a Referenced Method, the analyst
is required to repeat the procedure in Section 9.2. If the detection limit
of the method will be affected by the change, the laboratory is required
to demonstrate that the MDL (40 CFR Part 136, Appendix B) is lower
than the MDL for the Referenced Method or one-third of the regulatory
compliance level, whichever is higher. If calibration will be affected by
the change, the analyst must recalibrate the instrument per Section 9 of
the Referenced Method.
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9.1.2.2 The laboratory is required to maintain records of modifications made to
this QC Supplement or the Referenced Methods. These records include
the following, at a minimum:
9.1.2.2.1 The names, titles, addresses, and telephone numbers of
the analyst(s) who performed the analyses and
modification, and of the quality control officer who
witnessed and will verify the analyses and modification.
9.1.2.2.2 A listing of metals measured, by name and CAS
Registry number.
9.1.2.2.3 A narrative stating reason(s) for the modification(s).
9.1.2.2.4 Results from all quality control (QC) tests comparing the
modified method to. the Referenced Method, including:
a) Calibration
b) Calibration verification
c) Initial precision and recovery (Section 9.2 of this
QC Supplement).
d) Analysis of blanks
e) Accuracy assessment
9.1.2.2.5 Data that will allow an independent reviewer to validate
each determination by tracing the instrument output
(peak height, area, or other signal) to the final result.
These data are to include, where possible:
a) Sample numbers and other identifiers.
b) Digestion/preparation or extraction dates.
c) Analysis dates and times.
d) Analysis sequence/run chronology.
e) Sample weight or volume.
f) Volume prior to each extraction/concentration
step.
g) Volume after each extraction/concentration step.
h) Final volume prior to analysis.
i) Injection volume.
j) Dilution data, differentiating between dilution of
a sample or extract.
k) Instrument and operating conditions (make,
model, revision, modifications).
1) Sample introduction system (ultrasonic
nebulizer, hydride generator, flow injection
system, etc).
m) Operating conditions (ashing temperature,
temperature program, flow rates, etc).
n) Detector (type, operating conditions, etc).
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o) Mass spectra, printer tapes, and other recordings
of raw data.
p) Quantitation reports, data system outputs, and
other data to link the raw data to the results
reported.
9.1.3 Analyses of blanks are required to demonstrate freedom from contamination. The
required types, procedures, and criteria for analysis of blanks are described in Section
9.5.
9.1.4 The laboratory shall spike at least 10% of the samples with the metal(s) of interest to
monitor method performance. This test is described in the Referenced Methods and in
Section 9.3 of this QC Supplement. When results of these spikes indicate atypical
method performance for samples, an alternative extraction or cleanup technique must be
used to bring method performance within acceptable limits. If method performance for
spikes cannot be brought within the limits given in .this QC Supplement, the result may
not be reported for regulatory compliance purposes.
9.1.5 The laboratory shall, on an ongoing basis, demonstrate through calibration verification
and through analysis of the ongoing precision and recovery aliquot that the analytical
system is in control. These procedures are described in Section 9 of the Referenced
Methods and Sections 10.2 and 9.6 of this QC Supplement.
9.1.6 The laboratory shall maintain records to define the quality of data that are generated.
Development of accuracy statements is described in Section 9.3.4.
9.2 Initial demonstration of laboratory capability
9.2.1 Method detection limit-To establish the ability to the trace metals of interest, the analyst shall
determine the MDL for each analyte per the procedure in 40 CFR 136, Appendix B using the
apparatus, reagents, and standards the will be used in the practice of this QC Supplement and the
Referenced Method. The laboratory must produce an MDL that is no more than 1/10 the
regulatory compliance level or that is less than the MDL listed in Table 1, whichever is greater.
9.2.2 Initial precision and recovery (IPR)—To establish the ability to generate acceptable precision and
' recovery, the analyst shall perform the following operations.
9.2.2.1 Analyze four aliquots of reagent water spiked with the metal(s) of interest at 2 -
3 times the Minimum Level (Table 1), according to the procedures in the
Referenced Method. All digestion, extraction, and concentration steps, and the
containers, labware, and reagents that will be used with samples, must be used
in this test.
9.2.2.2 Using results of the set of four analyses, compute the average percent recovery
(X) for the metal(s) in each aliquot and the standard deviation of the recovery (s)
for each metal.
9.2.2.3 For each metal, compare s and X with the corresponding limits for initial
precision and recovery in Table 2. If s and X for all metal (s) meet the
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acceptance criteria, system performance is acceptable and analysis of blanks and
samples may begin. If, however, any individual s exceeds the precision limit or
any individual X falls outside the range for accuracy, system performance is
unacceptable for that metal. Correct the problem and repeat the test (Section
9.2.2.1).
9.3 Method accuracy—To assess the performance of the method on a given sample matrix, the
laboratory must perform matrix spike (MS) and matrix spike duplicate (MSD) sample analyses
on 10% of the samples from each site being monitored, or at least one matrix spike sample
analysis and one matrix spike duplicate sample analysis must be performed for each sample set
(samples collected from the same site at the same time, to a maximum of 10 samples), whichever
is'more frequent. ,
9.3.1 The concentration of the MS and MSD is determined as follows:
9.3.1.1 If, as in compliance monitoring, the- concentration of a specific metal in
the sample is being checked against a regulatory concentration limit, the
spike must be at that.limit or at 5 times the background concentration,
whichever is greater.
9.3.1.2 If the concentration is not being checked against a regulatory limit, the
concentration must be at 5 times the background concentration or at 5
times the ML in Table 1, whichever is greater.
9.3.2 Assessing spike recovery
9.3.2.1 Determine the background concentration (B) of each metal by analyzing
one sample aliquot according to the procedures specified in the
Referenced Method.
9.3.2.2 If necessary, prepare a QC check sample concentrate mat will produce
the appropriate level (Section 9.3.1) in the sample when the concentrate
is added.
9.3.2.3 Spike a second sample aliquot with the QC check sample concentrate and
analyze it to determine the concentration after spiking (A) of each metal.
9.3.2.4 Calculate each percent recovery (P) as 100(A-B)/T, where T is the
known true value of the spike.
9.3.3 Compare the percent recovery (P) for each metal with the corresponding QC acceptance
criteria found in Table 2. If any individual P falls outside the designated range for
recovery, that metal has failed the acceptance criteria.
9.3.3.1 For a metal that has failed the acceptance criteria, analyze the ongoing
precision and recovery standard (Section 9.6). If the OPR is within its
respective limit for the metal(s) that failed (Table 2), the analytical
system is in control and the problem is attributable to the sample matrix.
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9.3.3.2 For samples that exhibit matrix problems, further isolate the metal(s)
from the sample matrix using chelation, extraction, concentration,
hydride generation, or other means, and repeat the accuracy test (Section
9.3.2).
9.3.3.3 If the recovery for the metal remains outside the acceptance criteria, the
analytical result for that metal in the unspiked sample is suspect and may
not be reported for regulatory compliance purposes.
9.3.4 Recovery for samples should be assessed and records maintained.
9.3.4.1 After the analysis of five samples of a given matrix type (river water,
lake water, etc.) for which the metal(s) pass the tests in Section 9.3.3,
compute the average percent recovery (R) and the standard deviation of
the percent recovery (SR) for the metal(s). Express the accuracy
assessment as a percent recovery interval from R - 2SR to R + 2SR for
each matrix. For example, if R = 90% and SR = 10% for five
analyses of river water, the accuracy interval is expressed as 70 - 110%.
9.3.4.2 Update the accuracy assessment for each metal in each matrix on a
regular basis (e.g., after each five to ten new measurements).
9.4 Precision of matrix spike duplicates
9.4.1 Calculate the relative percent difference (RPD) between the MS and MSD per the
equation below using the concentrations found in the MS and MSD. Do not use the
recoveries calculated in Section 9.3.2.4 for this calculation because the RPD of recoveries
is inflated when the background concentration is near the spike concentration.
RPD = ioo
(D1+D2)I2
where:
Dl = concentration of the analyte in the MS sample
D2 = concentration of the analyte in the MSD sample
9.4.2 The relative percent difference between the matrix spike and the matrix spike duplicate
must meet the acceptance criteria in the Referenced Method, or must be less than 20
percent if a criterion for duplicates is not given in the Referenced Method. If the criteria
are not met, the analytical system is be judged to be out of control. In this case, correct
the problem and reanalyze all samples in the sample set associated with the MS/MSD
which failed the RPD test.
9.5 Blanks-Blanks are analyzed to demonstrate freedom from contamination.
9.5.1 Laboratory (method) blank
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9.5.1.1 Prepare a method blank with each sample batch (samples of the same
matrix started through the extraction process on the same 12-hour shift,
to a maximum of 10 samples). Analyze the blank immediately after
analysis of the OPR (Section 9.6) to demonstrate freedom from
contamination.
9.5.1.2 If the metal of interest or any potentially interfering substance is found
hi the blank at a concentration equal to or greater than the MDL (Table
1), then sample analysis must be halted, the source of the contamination
determined, the problem corrected, and the sample batch and fresh
method blank reanalyzed.
9.5.1.3 Alternatively, if a sufficient number of blanks (3 minimum) are analyzed
to characterize the nature of a blank, the average concentration plus two
standard deviations must be less than the regulatory compliance level.
/
9.5.1.4 If the result for a single blank remains above the MDL or if the result
for the average concentration plus two standard deviations of three or
more blanks exceeds the regulatory compliance level, results for samples
associated with those blanks may not be reported for regulatory
compliance purposes. Stated another way, results for all initial precision
and recovery tests (Section 9.2) and all samples must be associated with
an uncontaminated method blank before these results may be reported for
regulatory compliance purposes.
9.5.2 Field blank
9.5.2.1 Analyze the field blank(s) shipped with each set of samples (samples
collected from the same site at the same time, to a maximum of 10
samples). Analyze the blank immediately prior to analysis of the
samples in the batch. .
9.5.2.2 If the metal of interest or any potentially interfering substance is found
in the field blank at a concentration equal to or greater than the MDL
(Table 1), or greater than one-fifth the level in the associated sample,
whichever is greater, then results for associated samples may be the
result of contamination and may not be reported for regulatory
. . compliance purposes.
9.5.2.3 Alternatively, if a sufficient number of field blanks (3 minimum) are
analyzed to characterize the nature of the field blank, the average
concentration plus two standard deviations must be less than the
regulatory compliance level or less than one-half the level in the
associated sample, whichever is greater.
9.5.2.4 If contamination of the field blanks and associated samples is known or
suspected, the laboratory should communicate this to the sampling team
so that the .source of contamination can be identified and corrective
measures taken prior to the next sampling event.
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9.5.3 Equipment Blanks—Prior to the use of any sampling equipment at a given site, the
laboratory or cleaning facility is required to generate equipment blanks in order to
demonstrate that the sampling equipment is free from contamination. Two types of
equipment blanks are required: bottle blanks and sampler check blanks.
9.5.3.1 Bottle blanks—After undergoing appropriate cleaning procedures (Section
11.4), bottles should be subjected to conditions of use to verify the
effectiveness of the cleaning procedures. A representative set of sample
bottles should be filled with reagent water acidified to pH<2 and
allowed to stand for a minimum of 24 hours. Ideally, the time that the
bottles are allowed to stand should be as close as possible to the actual
time that sample will be in contact with the bottle. After standing, the
water should be analyzed for any signs of contamination. If any bottle
shows signs of contamination, the problem must be identified, the
cleaning procedures corrected or cleaning solutions changed, and all
affected bottles recleaned.
9.5.3.2 Sampler check blanks-Sampler check blanks are generated in the
laboratory or at the equipment cleaning contractor's facility by
processing reagent water through the sampling devices using the same
procedures that are used in the field (see Sampling Method). Therefore,
the "clean hands/dirty hands" technique utilized during field sampling
should be followed when preparing sampler check blanks at the
laboratory or cleaning facility.
9.5.3.2.1 Sampler check blanks are generated by filling a large
carboy or other container with reagent water (Section
7.2) and processing the reagent water through the
equipment using the same procedures that are used in the
field (see Sampling Method). For example, manual grab
sampler check blanks are collected by directly
submerging a sample bottle into the water, filling the
bottle, and capping. Subsurface sampler check blanks
are collected by immersing the sampler into the water
and pumping water into a sample container. "Clean
hands/dirty hands" techniques must be used.
9.5.3.2.2 The sampler check blank must be analyzed using the
procedures given in the QC Supplement and the
Referenced Methods. If any metal of interest or any
potentially interfering substance is detected in the blank,
the source of contamination/interference must be
identified, and the problem corrected. The equipment
must be demonstrated to be free from the metal(s) of
interest before the equipment may be used in the field.
9.5.3.2.3 Sampler check blanks must be run on all equipment that
will be used in the field. If, for example, samples are to
be collected using both a grab sampling device and a
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subsurface sampling device, then a sampler check blank
must be run on both pieces of equipment.
9.6 • Ongoing precision and recovery
9.6.1 Prepare a precision and recovery sample (laboratory fortified method blank) identical to
the initial precision and recovery aliquots (Section 9.2) with each sample batch (samples
of the same matrix started through the extraction process on the same 12-hour shift, to
a maximum of 10 samples) by spiking an aliquot of reagent water with the metal(s) of
interest.
9.6.2 Analyze the OPR aliquot prior to analysis of the method blank and samples.from the
same batch.
9.6.3 Compute the percent recovery of each metal in the OPR aliquot using the procedure
given in the Referenced Method.
9.6.4 For each metal, compare the concentration to the limits for ongoing recovery in Table
2. If all metals meet the acceptance criteria, system performance is acceptable and
analysis of blanks and samples may proceed. If, however, any individual recovery falls
outside of the range given, the analytical processes are not being performed properly for
that metal. In this event, correct the problem, re-prepare, extract, and clean up the
sample batch and repeat the ongoing precision and recovery test (Section 9.6).
9.6.S Add results that pass the specifications in Section 9.6.4 to initial and previous ongoing
data for each metal in each matrix. Update QC charts to form a graphic representation
of continued laboratory performance. Develop a statement of laboratory accuracy for
each metal in each matrix type by calculating the average percent recovery (R) and the
standard deviation of percent recovery (SR). Express the accuracy as a recovery interval
from R - 2SR to R + 2SR. For example, if R = 95% and SR = 5%, the accuracy is
85 to 105%.
9.7 The specifications contained in this QC Supplement can be met if the instrument used is calibrated
properly and then maintained in a calibrated state. A given instrument will provide the most
reproducible results if dedicated to the settings and conditions required for the analyses of metals
by the Referenced Method and this QC Supplement.
9.8 . Depending on specific program requirements, field duplicates may be collected to determine the
precision of the sampling technique. The relative percent difference (RPD) between field
duplicates should be less than 20%.
10.0 CALIBRATION AND CALIBRATION VERIFICATION
10.1 Calibration—Calibrate the instrument as given in the Referenced Method. Calibrate at a minimum
of three points, one of which must be the Minimum Level (Table 1), and another which must be
near the upper end of the calibration range. Calibration is required before any samples or blanks
are analyzed.
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QC Supplement for Determination of Trace Metals at EPA WQC Levels
10. 1 . 1 Internal standard calibration
10.1.1.1 Calculate the relative response factor (RRF) for each metal in each CAL
solution using the equation below and the height or area of the internal
standard. The RRF is unitless, but units used to express quantities of the
metals and internal standard must be identical.
where:
Rx = height or area of the signal for the metal
Ris = height or area of the signal for the internal standard.
Cx = concentration of compound injected G*g/L)
Cis = concentration of internal standard injected (/ig/L)
10.1.1.2 For each metal, calculate the mean RRF (M), the standard deviation of
the RRF (SD), and the relative standard deviation (RSD) from each
mean, where RSD = 100 x SD/M.
10.1.1.3 Linearity - If the RSD of the mean RRF for any metal is less than 15
percent over the calibration range, an averaged relative response factor
may be used for that analyte. Otherwise, a calibration curve for that
metal must be used over the calibration range.
10.1.2 External standard calibration
10.1.2.1 Calculate the response factor (RF) for each metal in each CAL solution
using the equation below and the height or area produced by the metal.
where:
Rx = height or area of the signal for the metal
Cx = concentration of compound injected Qig/L)
10. 1 .2.2 For each metal, calculate the mean RF (M), the standard deviation of the
RF (SD), and the relative standard deviation (RSD) of the mean, where
RSD = 100 x SD/M.
10.1.2.3 Linearity - If the RSD of the mean RF for any metal is less than 25
percent over the calibration range, an averaged response factor may be
used for that analyte. Otherwise, a calibration curve for that metal must
be used over the calibration range.
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QC Supplement for Determination of Trace Metals at EPA WQC Levels
10.1.3 Acceptable calibration curves for both internal and external standard calibration are first
order (linear with non-zero intercept) for GFAA, and first order or second order
(quadratic with a square term and with or without a zero intercept) for other
instrumentation. Third order (cubic term) curves, spline fits, and other irregular curves
are not representative of calibration data and may not be used.
10.2 Calibration verification—Immediately following calibration, an initial calibration verification
should be performed. Adjustment of the instrument is performed until verification criteria are
met. Only after these criteria are met may blanks and samples be analyzed.
10.2.1 Verify the specificity of the instrument for each metal and adjust the wavelength or
tuning until the resolving power specified in the Referenced Method is met.
10.2.2 Inject the mid-point calibration standard (Section 10.1) or laboratory performance check
solution specified in the Referenced Method.
10.2.3 Compute the percent recovery of each metal using the mean response or calibration curve
obtained in the initial calibration.
10.2.4 For each metal, compare the recovery with the corresponding limit for calibration
verification in Table 2. If all metals meet the acceptance criteria, system performance
is acceptable and analysis of blanks and samples may continue using the response from
the initial calibration. If any individual value falls outside the range given, system
performance is unacceptable for that compound. In this event, locate and correct the
problem and/or prepare a new calibration check standard and repeat the test (Section
10.2.2 - 10.2.4), or recalibrate the system per the Referenced Method and Section 10.1.
10.2.5 Calibration should be verified following every ten samples by analyzing the mid-point
calibration standard. If the recovery does not meet the acceptance criteria specified in
Table 2, analysis must be halted, the problem corrected, and the instrument recalibrated.
All samples after the last acceptable calibration verification must be reanalyzed.
11.0 CLEANING THE APPARATUS
11.1 All sampling equipment, sample containers, and lab ware should be cleaned in a designated
cleaning area that has been demonstrated to be free of trace element contaminants. Such areas
may include class. 100 clean rooms as. described by Moody (Reference 17.14), labware cleaning
areas as described by Patterson and Settle (Reference 17.6), or clean benches.
11.2 Materials, such as gloves (Section 6.2.4), storage bags (Section 6.2.7), and plastic wrap (Section
6.2.8), may be used new without additional cleaning unless the results of the equipment blank
pinpoint any of these materials as a source of contamination. In this case, either an alternate
supplier must be obtained or the materials must be cleaned.
11.3 For new Apparatus and Apparatus known or suspected to be contaminated, initial cleaning outside
of the clean room using detergent and concentrated, technical grades of acid is a prudent means
of reducing the initial contamination and ensuring that contamination is not brought into the clean
facility.
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QC Supplement for Determination of Trace Metals at EPA WQC Levels
11.4 Cleaning procedure
11.4.1 Bottles, labware, and sampling equipment
»
11.4.1.1 Fill a pre-cleaned basin (Section 6.2.5) with a sufficient quantity of a
0.5% solution of liquid detergent (Section 6.4), and completely immerse
each piece of ware. Allow to soak in the detergent for at least 30
minutes.
11.4.1.2 Using a pair of clean gloves (Section 6.2.4) and clean non-metallic
brushes (Section 6.2.6), thoroughly scrub down all materials with the
detergent.
11.4.1.3 Place the scrubbed materials in a pre-cleaned basin. Change gloves.
11.4.1.4 Thoroughly rinse the inside and outside of each piece with reagent water
until there is no sign of detergent residue (e.g., until all soap bubbles
disappear).
11.4.1.5 Change gloves, immerse the rinsed equipment in a hot (50-60 °C) bath
of concentrated reagent grade HNO3 (Section 7.1.1) and allow to soak
for at least two hours.
11.4.1.6 After soaking, use clean gloves and tongs to remove the Apparatus and
thoroughly rinse widi distilled, deionized water (Section 7.2).
11.4.1.7 Change gloves, immerse all equipment in a hot (50-60 °C) bath of IN
trace metal grade HC1 (Section 7.1.5), and allow to soak for at least 48
hours.
11.4.1.8 Thoroughly rinse all equipment and bottles with reagent water. Proceed
with Section 11.4.2 for labware and sampling equipment. Proceed with
Section 11.4.3 for sample bottles.
11.4.2 Labware and sampling equipment
11.4.2.1 After cleaning, air dry in a class 100 clean air bench.
11.4.2.2 After drying, wrap each piece of ware/equipment in two layers of
polyethylene film.
11.4.3 Fluoropolymer sample bottles—These bottles should be used if mercury is a target
analyte.
11.4.3.1 After cleaning, fill sample bottles with 0.1 % (v/v) ultrapure HC1 (Section
7.1.9) and cap tightly. It may be necessary to use a strap wrench to
assure a tight seal.
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QC Supplement for Determination of Trace Metals at EPA WQC Levels
11.4.3.2 After capping, double bag each bottle in polyethylene zip-type bags.
Store at room temperature until sample collection.
* 11.4.4 Bottles, labware, and sampling equipment (polyethylene or other material besides
fluoropolymer)
11.4.4.1 Apply the steps outlined above in Section 11.4.1.1 - 11.4.1.8 to all
bottles, labware, and sampling equipment. Proceed with Section
11.4.4.2 for bottles or Section 11.4.4.3 for labware and sampling
equipment.
11.4.4.2 After cleaning, fill bottles with 0.1 % (v/v) ultrapure HC1 (Section 7.1.9).
Double bag each bottle in a polyethylene bag to prevent contamination
of the surfaces with dust and dirt. Store at room temperature until
sample collection.
\ 1.4.4.3 After rinsing labware and sampling equipment, air dry in a class 100
clean air bench. After drying, wrap each piece of ware/equipment in
two layers of polyethylene film.
NOTE: Polyethylene bottles cannot be used to collect samples that will be
analyzed for mercury at trace (e.g., 0.012 /ig/L) levels due to the
potential of vapors diffusing through the polyethylene.
11.4.4.4 Polyethylene bags-if polyethylene bags need to be cleaned, clean per the
following procedure:
11.4.4.4.1 Partially fill with cold, (1 + 1) HNO3 (Section 7.1.2) and
x rinse with distilled deionized water (Section 7.2).
11.4.4.4.2 Dry by hanging upside down from a plastic line with a
plastic clip.
11.4.6 Silicone tubing, fluoropolymer tubing, and other sampling apparatus-Clean any silicone,
fluoropolymer, or other tubing used to collect samples by rinsing with 10% HC1 (Section 7.1.6)
and flushing with water from the site before sample collection.
11.4.7 Extension pole—Due to its length, it is impractical to submerse the two-meter polyethylene
extension pole (used in with the optional grab sampling device) in acid solutions as described
above. If such an extension pole is used, a non-metallic brush (Section 6.2.6) should be used to
scrub the pole with reagent water and the pole wiped down with acids described in Section 11.4.4
above. After cleaning, the pole should be wrapped in polyethylene film.
11.5 Storage—Store each piece or assembly of the Apparatus in a clean, single polyethylene zip-type
bag. If shipment is required, place the bagged apparatus in a second polyethylene zip-type bag.
11.6 All cleaning solutions and acid baths should be periodically monitored for accumulation of metals
which could lead to contamination. When levels of metals in the solutions become too high, the
22 December 1994
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QC Supplement for Determination of Trace Metals at EPA WQC Levels
solutions and baths should be changed and the old solutions discarded in compliance with state
and federal regulations.
12.0 SAMPLE ANALYSIS
12.1 For trivalent chromium, analyze the samples by graphite furnace atomic absorption (GFAA)
spectroscopy using EPA Method 200.9 and the QC Supplement. Do not perform the sample
preparation procedures listed in Section 11 of EPA Method 200.9 for trivalent chromium. The
method of standard additions may be necessary if matrix interferences are present.
12.2 For all other analytes, detailed procedures for sample processing and analysis are given in each
of the Referenced Methods.
13.0 DATA ANALYSIS AND CALCULATIONS
13.1 Compute the concentration of each metal in /ig/L (parts-per-billion; ppb) using the calibration
data.
13.2 If the concentration of the metal exceeds the calibration range of the instrument, dilute the sample
by successive factors of 10 until the concentration is within the calibration range.
13.3 Report results at or above the ML for metals found in samples and determined in standards.
Report all results for metals found in blanks, regardless of level.
13.4 Report results to one significant figure at or below the MDL, two significant figures between the
MDL and ML, and three significant figures at or above the ML.
13.5 Do not perform blank subtraction on the sample results.
14.0 METHOD PERFORMANCE
Performance data are given in the Referenced Methods.
15.0 POLLUTION PREVENTION
15.1 The acids used in this method should be reused as practicable by purifying by electrochemical
techniques. The only other chemicals used in this method are the neat materials used in preparing
standards. These standards are used in extremely small amounts and pose little threat to the
environment when managed properly.
15.2 Standards should be prepared in volumes consistent with laboratory use to minimize the volume
of expired standards to be disposed.
December 1994 23
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QC Supplement for Determination of Trace Metals at EPA WQC Levels
16.0 WASTE MANAGEMENT
16.1 It is the laboratory's responsibility to comply with all federal, state, and local regulations
- governing waste management, particularly the discharge regulations, hazardous waste
identification rules, and land disposal restrictions; and to protect the air, water, and land by
minimizing and controlling all releases from fume hoods and bench operations.
16.2 Samples preserved with acid to pH <2 are hazardous and must be neutralized before being
poured down a drain or must be handled as hazardous waste.
16.3 For further information on waste management, consult "The Waste Management Manual for
Laboratory Personnel" and "Less is Better-Laboratory Chemical Management for Waste
Reduction," available from the American Chemical Society's Department of Government
Relations and Science Policy, 1155 16th Street N.W., Washington, D.C. 20036.
17.0 REFERENCES
17.1 Adeloju, S.B.; Bond, A.M. Anal. Chem. 1985, 57, 1728. "Influence of Laboratory Environment
on the Precision and Accuracy of Trace Element Analysis."
17.2 Berman, S.S.; Yeats, P.A. CRC Reviews in Analytical Chemistry 1985, 16, 1. "Sampling of
Sea water for Trace Metals."
17.3 Bloom, N.S. Presented at the 16th Annual EPA Conference on the Analysis of Pollutants in the
Environment, Norfolk, Virginia, May 5, 1993. "Ultra-Clean Sampling, Storage, and Analytical
Strategies for the Accurate Determination of Trace Metals in Natural Waters."
17.4 Bruland, K.W. Chemical Oceanography 1983, 8, 157. "Trace Elements in Seawater."
17.5 Nriagu, J.O.; Larson, G.; Wong, H.K.T.; Azcue, J.M. J. Great Lakes Research 1993,19, 175.
"A Protocol for Minimizing Contamination in the Analysis of Trace Metals in Great Lakes
Waters."
17.6 Patterson, C.C.; Settle, D.M. In National Bureau of Standards Special Publication 422; LaFleur,
P.O., Ed., U.S. Government Printing Office, Washington, DC, 1976. "Accuracy in Trace
Analysis."
17.7 Prothro, Martha G., "Office of Water Policy and Technical Guidance on Interpretation and
Implementation of Aquatic Life Metals Criteria", EPA Memorandum to Regional Water
Management and Environmental Services Division Directors, October 1, 1993.
17.8 "Format for Method Documentation", Distributed by the EPA Environmental Monitoring
Management Council, Washington, DC, November 18, 1993.
17.9 Methods 1624 and 1625, 40 CFR Part 136, Appendix A.
17.10 Anal. Chem. 1983, 14, 2210.
24 December 1994
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QC Supplement for Determination of Trace Metals at EPA WQC Levels
17.11 Windom, H.L; Byrd, J.T.; Smith, R.G., Jr.; Huan, F. Environ. Sci. Technol. 1991, 25, 1137.
"Inadequacy of NASQAN Data for Assessing Metal Trends in the Nation's Rivers."
17.12' Zief, M.; Mitchell, J.W. in Chemical Analysis; 1976; Vol. 47 "Contamination Control in Trace
Metals Analysis;" Chapter 6.
17.13 Handbook of Analytical Quality Control in Water and Wastewater Laboratories; U.S.
Environmental Protection Agency. EMSL-Cincinnati, OH, March 1979; EPA-600/4-79-019.
17.14 Moody, J.R. Anal. Chem. 1982, 54, 1358A. "NBS Clean Laboratories for Trace Element
Analysis."
18.0 Glossary of Definitions and Purposes
These definitions and purposes are specific to this QC Supplement but have been conformed to
common usage as much as possible.
18.1 Analyte - A metal tested for by the methods referenced in this QC Supplement. The analytes
are listed in Table 1.
18.2 Apparatus — The sample container and other containers, filters, filter holders, labware, tubing,
pipets, and other materials and devices used for sample collection or sample preparation, and that
will contact samples, blanks, or analytical standards.
18.3 Calibration standard (CAL) — A solution prepared from a dilute mixed standard and/or stock
solutions and used to calibrate the response of the instrument with respect to analyte
concentration.
18.4 Equipment blank — An aliquot of reagent water that is subjected in the laboratory to all aspects
of sample collection and analysis, including contact with all sampling devices and apparatus. The
purpose of the equipment blank is determine if the sampling devices and apparatus for sample
collection have been adequately cleaned prior to shipment to the field site. An acceptable
equipment blank must be achieved before the sampling devices and apparatus are used for sample
collection. In addition, equipment blanks should be run on random, representative sets of gloves,
storage bags, and plastic wrap for each lot to determine if these materials are free from
contamination prior to use.
18.5 Field blank — An aliquot of reagent water that is placed in a sample container in the laboratory,
shipped to the field, and treated as a sample in all respects, including contact with the sampling
devices and exposure to sampling site conditions, storage, preservation, and all analytical
procedures, which may include filtration. The purpose of the field blank is to determine if the
field or sample transporting procedures and environments have contaminated the sample.
18.6 Field duplicates (FD1 and FD2) - Two separate samples collected in separate sample bottles at
the same time and place under identical circumstances and treated exactly the same throughout
field and laboratory procedures. Analyses of FD1 and FD2 give a measure of the precision
associated with sample collection, preservation, and storage, as well as with laboratory
procedures.
December 1994 25
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QC Supplement for Determination of Trace Metals at EPA WQC Levels '
18.7 Initial precision and recovery (IPR) — Four aliquots of the ongoing precision and recovery
standard analyzed to establish the ability to generate acceptable precision and accuracy. EPRs are
performed prior to the first time a method is used and any time the method or instrumentation
' is modified. . .
18.8 Laboratory blank — An aliquot of reagent water that is treated exactly as a sample including
exposure to all glassware, equipment, solvents, reagents, internal standards, and surrogates that
are used with samples. The laboratory blank is used to determine if analytes or interferences
are present in the laboratory environment, the reagents, or the apparatus.
18.9 Laboratory control sample (LCS) - See Ongoing precision and recovery standard (OPR).
18.10 Laboratory duplicates (LD1 and LD2) — Two aliquots of the same sample taken in the laboratory
from the same sample bottle and analyzed separately using the referenced method. Analyses of
LD1 and LD2 indicate precision associated with laboratory procedures, but not with sample
collection, preservation, transportation, or storage procedures.
18.11 Laboratory fortified blank — See Ongoing precision and recovery standard (OPR).
18.12 Laboratory fortified sample matrix — See Matrix spike and matrix spike duplicate.
18.13 Laboratory reagent blank — See Laboratory blank.
18.14 Matrix spike (MS) and matrix spike duplicate (MSD) — Aliquots of an environmental sample to
which known quantities of the analytes are added in the laboratory. The MS and MSD are
analyzed exactly like a sample. Their purpose is to quantify the bias and precision caused by the
sample matrix. The background concentrations of the analytes in the sample matrix must be
determined in a separate aliquot and the measured values in the MS and MSD corrected for
background concentrations.
18.15 May — This action, activity, or procedural step is neither required nor prohibited.
18.16 May not — This action, activity, or procedural step is prohibited.
18.17 Method blank - See Laboratory blank.
18.18 Minimum level (ML) — The lowest level at which the entire analytical system gives a
recognizable signal and acceptable calibration point (Reference 9).
18.19 Must - This action, activity, or procedural step is required.
18.20 Ongoing precision and recovery standard - A laboratory blank spiked with known quantities of
analytes. The OPR is analyzed exactly like a sample. Its purpose is to assure that the results
produced by the laboratory remain within the limits specified in the Referenced Methods for
precision and accuracy:
18.21 Preparation blank — See Laboratory blank.
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QC Supplement for Determination of Trace Metals at EPA WQC Levels
18.22 Primary dilution standard — A solution containing the analytes that is purchased or prepared from
stock solutions and diluted as needed to prepare calibration solutions and other solutions.
18.23' Quality control sample (QCS) — A sample containing all or a subset of the analytes at known
concentrations. The QCS is obtained from a source external to the laboratory or is prepared from
a source of standards different from the source of calibration standards. It is used to check
laboratory performance with test materials prepared external to the normal preparation process.
18.24 Reagent water—water demonstrated to be free from the metal(s) of interest and potentially
interfering substances at the MDL for that metal in the Referenced Method or Additional Method.
18.25 Should — This action, activity, or procedural step is suggested but not required.
18.26 Stock solution — A solution containing an analyte that is prepared using a reference material
traceable to EPA, the National Institute of Science and Technology (NIST), or a source that will
attest to the purity and authenticity of the reference material.
December 1994 27
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Table 1
Lowest EPA Water Quality Criteria for Toxic Metals and Species; Existing EPA Methods that Achieve or
Come Closest to Achieving these Criteria; and Analytical Techniques, Minimum Levels, and Method
Detection Limits for these EPA Methods
Key:
Notes:
1.
2.
3.
4.
Metal
Antimony
Arsenic
Cadmium
Chromium (in)
Chromium (VI)
Copper
Lead
Mercury
Nickel
Selenium
Silver
Thallium
Zinc
Lowest EPA
Water
• Quality
Criterion
(r&LY
14
0.018
0.32
57
10.5
2.5
0.14
0.012
7.1
5
0.31
1.7
28
EPAMeth
Method
200.8
200.9
—
200.8
200.9
200.10
200.13
—
218.6
200.8'
200.10
200.8
200.10
200713
—
200.8
200.9
200.10
200.8
200.9
200.8
200.8
200.8
200.9
trd wialytV ftf tarhnifni
«/L
Technique
ICP/MS
STGFAA
—
ICP/MS
STGFAA
CC/ICP/MS
CC/STGFAA
• —
Ion Chrom.
ICP/MS
CC/ICP/MS
ICP/MS
CC/ICP/MS
CC/STGFAA
—
ICP/MS
STGFAA
CC/ICP/MS
ICP/MS
STGFAA
ICP/MS
ICP/MS
ICP/MS
STGFAA
IB, and MDL/ML in
MDL1
0.007
0.34
—
0.025
0.013
0.00094
0.0029
. —
0.23
0.043
0.0083
0.015
0.0039
0.012
—
0.33
0.65
0.013
1.2
0.69
0.018
0.007
0.069
0.10
ML*
0.02
1
—
0.1
0.05
0.002
0.01
—
0.5
0.1
0.02
0.05
0.01
0.05
—
1
2
0.05
5
2
0.05
0.02
0.2
0.2
WQClerd
achiered?1
Yes
Yes
No
Yes
Yes
Yes
Yes
No
Yes
Yes
Yes
No
Yes
Yes
No
Yes
Yes
Yes
No
No
Yes
Yes
Yes
Yes
ICP = Inductively coupled plasma Ion chrom
AES = Atomic emission spectrometry CC
MS = Mas* spectrometry CVAF
GFAA = Graphite furnace atomic abiorption spectrometry STGFAA
Ion chromatography
etiolation/concentration
Cold vapor atomic fluorescence
Stabilized temperature GFAA
Lowest of the freshwater, marine, and human health WQC promulgated by EPA for 14 states at 40 CFR Part 131 (57 FR 60848),
with hardness-dependent freshwater aquatic life criteria adjusted in accordance with 57 FR 60848 to reflect the worst case hardness
of 25 mg/L CaCO, and all aquatic life criteria adjusted in accordance with the 10/1/93 Office of Water guidance to reflect dissolved
metals criteria. A complete listing of all WQC, including total, dissolved, and levels calculated with a hardness of 25 mg/L CaCQ
and a hardness of 100 mg/L CtCO, is provided in Appendix A.
Determination of the metal is achieved if MDL it less than one-tenth the WQC level.
Method Detection Limit as determined by 40 CFR Part 136, Appendix B.
Minimum Level (ML) calculated by multiplying laboratory-determined MDL by 3.18 and rounding result to nearest multiple of 1,
2, 5, 10, 20, 50 etc. in accordance with procedures utilized by EAD and described in the EPA Draft .National Guidance for the
Permitting, Monitoring, and Enforcement of Water Quality-Based Effluent Limitations Set Below Analytical Detection/Quantitation
Levels, March 22, 1994.
28
December 1994
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QC Supplement for Determination of Trace Metals at EPA WQC Levels
Table 2
Quality Control Acceptance Criteria for Performance Tests1
Method
200.8
200.9
200.10
200.13
218.6
Metal
Antimony
Cadmium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Antimony
Cadmium
Nickel
Selenium
Zinc
Cadmium
Copper
Nickel
Lead
Cadmium
Lead
Chromium (IV)
Initial Precision and
Recovery (Section 93)
6 X
20 81-120
13 85-112
43 55-141
30 75-140
30 71-131
41 63-145
19 82-120
30 66-134
43 55-142
60 24-144
11 67-142
36 69-141
31 60-128
19 67-142
23 75-121
41 56-139
27 74-128
44 56-144
23 70-116
27 63-117
20 80 - 120
Calibration Verification
(Section 10.2)
90-111
91-105
76-120
91-120
86-116
83-125
91-111
82-118
76-121
54-114
86-123
87-123
77-111
86-123
86-1 10
77-119
87-115
78-122
81-105
77-103
90-110
Ongoing Precision and
Recovery (Section 9.6)
79-122
84-113
51-145
72-143
68-134
59-149
81-121
64-137
46-146
18-150
64-145
65-145
56-131
67-142
73-123
53-142
71-130
52-144
70-116
60-120
79-122
, Spike Recovery
(Section 9.3)
79-122
84-113
51-145
72-143
68-134
59-149
81-1212
64-137
46-146
18-150
64-145
65-145
56-131
67-142
73-123
53-142
71-130
52-1442
70-116
60-1202
79-122
1. All specification expressed as percent.
2. Based on preliminary laboratory data, spike recovery specifications for silver by Method 200.8 and lead by Methods 200.10 and
200.13 may need to be revised. Additional spike recovery data is pending.
December 1994
29
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SECTION 4
Guidance on the Documentation and Evaluation of
Trace Metals Data Collected for
CWA Compliance Monitoring
EPA Office of Water, Engineering & Analysis Division
-------
Guidance on the Documentation and Evaluation of
Trace Metals Data Collected for
Clean Water Act Compliance Monitoring
Draft
December 1994
U.S. Environmental Protection Agency
Office of Water
Office of Science and Technology
Engineering and Analysis Division (4303)
401 M St. SW
Washington, DC 20460
-------
Acknowledgements
This guidance was prepared under the direction of William A. Telliard of the Engineering and Analysis
Division (HAD) within the U.S. Environmental Protection Agency's (EPA) Office of Science and
Technology (OST). This guidance was prepared under EPA Contract 68-C3-0037 by DynCorp
Environmental, with the assistance of Interface, Inc.
Disclaimer
This document has been reviewed and approved for publication 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.
Further Information
For further information, contact:
William A. Telliard, Chief .
Analytical Methods Staff
Engineering and Analysis Division
U.S. Environmental Protection Agency
401 M Street
Washington, DC 20460
Phone: 202-260-7134
Fax: 202-260-7185
-------
Chapter 1
Introduction
Numerous organizations, such as state pollution control agencies, health departments, local
government agencies, industrial dischargers, research facilities, and federal agencies (e.g., EPA, USGS),
collect data on effluent and ambient metal concentrations for use in a variety of applications, including:
determining attainment status for water quality standards, discerning trends in water quality, estimating
effluent concentrations and variability, estimating background loads for total maximum daily loads
(TMDLs), assessing permit compliance, and conducting research1. The quality of data used is an
important issue, and, in particular, the quality of trace level metals data may be compromised due to
contamination during sampling, filtration, storage, and analysis. In fact, one of the greatest obstacles
faced by laboratories attempting trace metals determinations is the potential for contamination of samples
during the sampling and analytical processes. Trace metals are ubiquitous in the environment, and
samples can readily become contaminated by numerous sources, including: metallic or metal-containing
labware, metal-containing reagents, or metallic sampling equipment; improperly cleaned and stored
equipment; and atmospheric inputs such as dirt, dust, or other particulates from exhaust or corroded
structures.
The measurement of trace metals at ambient EPA water quality criteria (WQC) levels has been
spurred by the increased emphasis on a water quality-based approach to the control of toxic pollutants.
Current ambient WQC levels2 for trace metals require measurement capabilities at levels as much as 280
times lower than those levels required to support technology-based controls or achievable by routine
analyses in environmental laboratories. The findings in the USGS and EPA studies strongly indicate that
rigorous steps must be taken in order to preclude contamination in future gathering of trace metals data.
In order to ensure that the data collected for trace metals determinations at ambient water quality
criteria levels are valid and not a result of contamination, rigorous quality control (QC) must be applied
to all sample collection, preparation, and analysis activities. EPA has published analytical methods (1983,
1991) for monitoring metals in waters and wastewaters, but these methods are inadequate for the
determination of ambient concentrations of metals in ambient waters due to the lack of some or all of the
essential quality control criteria. This has prompted the Engineering and Analysis Division (BAD) to
develop a draft document for sampling, entitled Method 1669: Sampling Ambient Water for
Determination of Trace Metals at EPA Water Quality Criteria Levels (Method 1669), and a draft quality
control supplement to existing EPA metals methods entitled, Quality Control Supplement for
Determination of Trace Metals at EPA Water Quality Criteria Levels Using EPA Metals Methods (QC
Supplement), that include the rigorous sample handling and quality control procedures necessary to
deliver verifiable data at WQC levels.
' Prothro, M., Acting Assistant Administrator for Water, Memorandum to Water Management Division Directors and
Environmental Services Division Directors, Oct. 1, 1993.
2 "Water Quality Standards; Establishment of Numeric Criteria for Priority Toxic Pollutants; States' Compliance" (also
referred to as "The National Toxics Rule"). 40 CFR Part 131, (57 FR 60848, December 22, 1992).
December 1994
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Data Evaluation Guidance
Appropriate quality assurance (QA) and quality control (QC). procedures are the key to producing
precise and accurate data unbiased by contamination. Examination of trace metals data without data from
blanks and other QC analyses yields little or no information on whether sample data are reliable. Data
quality must be documented through the use of blanks (both field and laboratory blanks), standards,
matrix spike/matrix spike duplicates, and field duplicates, as well as other QC analyses. The results of
all QC procedures must be included in the data reporting package along with the sample results if data
quality is to be known.
The remainder of this document contains guidance that is intended to aid in the review of trace
metals data submitted for compliance monitoring purposes under the National Pollutant Discharge
Elimination System (NPDES) when these data were collected in accordance with Method 1669, the QC
Supplement, and the methods referenced in the QC Supplement. Chapter 2 of this document outlines the
data elements that must be reported by laboratories and permittees so that EPA reviewers can validate
the data. Chapter 3 provides guidance concerning the review of data"collected and reported in accordance
with Chapter 2. Chapter 4 provides a Data Inspection Checklist that can be used to standardize
procedures for documenting the findings of each data inspection.
The guidance provided in these chapters is similar in principle to the data reporting and review
guidance provided in EPA's Guidance on Evaluation, Resolution, and Documentation of Analytical
Problems Associated with Compliance Monitoring (EPA 821-B-93-001), but has been specifically adapted
to reflect particular concerns related to the evaluation of data for trace metals.
December 1994
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Chapter 2
Checklist of Laboratory Data Required
to Support Compliance Monitoring for Trace Metals
Determined in Accordance with Method 1669, the
QC Supplement, and the Referenced Methods
The items listed below describe the minimum data elements necessary to validate trace metals data
collected using the Method for Sampling Ambient Water for Determination of Trace Metals at EPA Water
Quality Criteria Levels (Method 1669) and the Quality Control Supplement for Determination of Trace
Metals at EPA Water Quality Criteria Levels Using EPA Metals Methods (QC Supplement) in conjunction
with EPA metals methods. It should be noted that since different instrumentation yields different data
output, the specific form of the data will vary according to the analytical method.
1. Method Number
The method number of the base EPA metals method used in conjunction with Method 1669 and
the QC Supplement must be provided. This information will allow a data reviewer to become familiar
with the method, if necessary, prior to reviewing the data. It will also assist the reviewer in making any
necessary determinations of the comparability of these data with previously reported data. If more than
one method is needed to cover a complement of analytes, then all method numbers must be provided.
A clear delineation of the specific method used for each given analyte is required. Also, the revision date
or revision level and number/letter of the method must be given, so that the reviewer tests the results
submitted against the specific method used. A list of the metals and metal species that have published
WQC levels and the corresponding EPA method(s) is provided in Table 1.
In recognition of advances that are occurring in analytical technology, the QC Supplement is
performance-based. That is, an alternate procedure or technique may be used if the performance
requirements in the reference method(s) and QC Supplement are met. The analyst must start with one
of the methods as a reference, and may improve upon this reference method to reduce interferences or
lower costs of measurements. Examples include using alternate chelating or ion exchange resins,
alternate matrix modifiers, additional cleanup techniques, or more sensitive detectors. The objective of
allowing method modifications is to improve method performance on the sample being analyzed. At no
time are changes that degrade method performance allowed. Section 9.1.2 of the QC Supplement gives
details of the tests and documentation required to support equivalent performance.
2. Detailed Narrative
A detailed narrative discussing any problems with the analysis, corrective actions taken, and
changes made to the reference method must be included in a complete data reporting package. Reasons
for changes to the reference method, supporting logic behind the technical approach to the change, and
the result of the change must be included in the narrative. The narrative should be written by an
analytical chemist in terms that another analytical chemist can understand.
December 1994
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Data Evaluation Guidance
3. . Summary Level Report or Data Report Forms
The complete data reporting package must include a summary level report or data reporting forms
that list all samples analyzed, the metals and metal species determined, and the concentrations found.
Analytes detected in field samples at concentrations below the minimum level (ML) must be reported as
non-detect. However, all analyte concentrations detected in blank samples must be reported, regardless
of the level. Results must be listed for each sample analyzed, including any dilutions and reanalyses.
Metals should be listed by name and CAS Registry number.
The ML is the quantitation level as defined by the QC Supplement and the reference EPA
method. The laboratory is required to determine the MDL for each analyte in accordance with the
procedures described in 40 CFR Part 136, Appendix B- Definition and Procedure for Determination of
Method Detection Limit - Revision 1.11. That MDL multiplied by 3.18 must be less than or equal to the
ML given in the Table 1 of the QC Supplement.
4. Summary of Quality Control Results
Results for all quality control analyses required by the reference EPA method and the QC
Supplement must be presented in the complete data reporting package. Certain expanded QC procedures
in the QC Supplement take precedence over the corresponding QC procedures in the reference methods.
It must be clearly evident which QC corresponds to a given method and" set of samples if more than one
base method was used or if more than one set of samples was analyzed.
Results for QC procedures that must be provided include, but are not limited to, the following
(where applicable):
• Instrument tuning
• . Calibration
• Calibration verification (initial and following every 10 analytical samples)
• Initial precision and recovery
• Ongoing precision and recovery
• Blanks
Laboratory (method) blanks
Field blanks
Calibration blanks
Equipment blanks
• Matrix spike/matrix spike duplicates
• Field duplicates
• Method of standard additions (MSA) results
• Spectral interference checks
• Serial dilutions
• Internal standard recoveries
• Method detection limits
• Quality control charts and limits
Table 2 lists the required frequency and purpose of the QC procedures.
4 December 1994
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Data Evaluation Guidance
5. • Raw Data . .
Raw data and other information that will allow an independent reviewer to- validate each
determination and calculation performed by the laboratory must be included in the data reporting package.
The instrument output (emission intensity, peak height, area, or other signal intensity) must be traceable
from the raw data to the final result reported. The raw data must be provided for not only the analysis
of each field sample but also for all calibrations, verifications, blanks, matrix spike/matrix spike
duplicates, field duplicates, and other QC analyses required by the base method and QC Supplement.
Raw data are method and instrument specific and may include, but are not limited to, the
following:
• Sample numbers and other identifiers
• Digestion/preparation or extraction dates
• Analysis dates and times
• Analysis sequence/run chronology
• Sample weight or volume
• Volume prior to each extraction/concentration step
• Volume after each extraction/concentration step
• Final volume prior to analysis
• Injection volume
• Matrix modifiers
• Dilution data, differentiating between dilution of a sample or an extract
• Instrument (make, model, revision, modifications)
• Sample introduction system (ultrasonic nebulizer, hydride generator, flow injection system, etc.)
• Column (manufacturer, length, diameter, chelating or ion exchange resin, etc.)
• Operating conditions (char/ashing temperatures, temperature program, incident rf power, flow
rates, plasma viewing height, etc.)
• ' Detector (type, wavelength, slit, analytical mass monitored, etc.)
• Background correction scheme
• Quantitation reports, data system outputs, and other.data to link the raw data to the results
reported
• Direct instrument readouts (e.g., strip charts, mass spectra, printer tapes, and other recordings
of raw data) and other data to support the final results
• Lab bench sheets and copies of all pertinent logbook pages for all field and QC sample
preparation and cleanup steps, and for all other parts of the determinations
6. Example Calculations
Example calculations that will allow an independent reviewer to determine how the laboratory
used the raw data to arrive at a final result must be provided in the data reporting package. Useful
examples include both detected 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
December 1994
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Data Evaluation Guidance
calculation. Adjustments made for sample volume, dilution, internal standardization, etc. should be
evident. " •
7. Magnetic Media
It is not necessary for the laboratory or responsible organization to submit digitized binary,
hexadecimal, or other raw signal recordings with the data package. However, the laboratory that
performs the analysis should archive these data so that the raw reduced data can be reconstructed, and
the laboratory or organization responsible for reporting the data should be prepared to submit raw data
on magnetic media, upon request by EPA. Magnetic media may be required for automated data review,
for diagnosis of data reduction problems, or for establishment of an analytical database.
8. Names, Titles, Addresses, and Telephone Numbers of Analysts and QC Officer
The names, titles, addresses, and telephone numbers of the analysts who performed the
determinations and the quality control officer who verified the results must be included in the data
reporting package. If the data package is being submitted by a person or organization other than the
analytical laboratory, it is that person or organization's responsibility to ensure that the laboratory
provides all the data listed above and that all method requirements are met. For example, with regards
to effluent or ambient monitoring data submitted by an NPDES permittee on a Discharge Monitoring
Report (DMR), the task of collecting and reporting quality control data falls to the permittee.
. In addition, the personnel, titles, addresses, telephone numbers, and name (if different from the
laboratory that analyzed the field samples) of the facility that cleaned and shipped the sampling equipment
and generated the equipment blanks, the laboratory (if different) that analyzed the equipment blanks, and
the facility responsible for the collection, filtration, and transport of the field samples to the laboratory
must be obtained and included in the data reporting package.
December 1994
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Table 1
Analytes Amenable to Collection and Determination Using the Sampling Method, the QC Supplement,
and the Base Methods; Lowest Ambient Water Quality Criterion for Each Metal or Metal Species; and
Method Numbers, Analytical Techniques, Method Detection Limits, and Minimum Levels for the
Applicable EPA Methods
Key:
Notes:
1.
2.
3.
4.
Metal
Antimony
Arsenic
Cadmium
Chromium (III)
Chromium (VI)
Copper
Lead
Mercury
Nickel
Selenium
Silver
Thallium
Zinc
Lowest EPA'
Water
Quality
Criterion
G»g/L)'
14
0.018
0.32
57
10.5
2.5
0.14
0.012
7.1
5
0.31
1.7
28
EPA Method, analytical technique, and MDL/ML in
Mg/L
Method
200.8
200.9
—
200.8
200.9
200.10
200.13
—
218.6
200.8
200.10
200.8
200.10
200.13
—
200.8
200.9
200.10
200.8
200.9
200.8
200.8
200.8
200.9
Technique
ICP/MS
STGFAA
...
ICP/MS
STGFAA
CC/ICP/MS
CC/STGFAA
'
Ion Chrom.
ICP/MS
CC/ICP/MS
ICP/MS
CC/ICP/MS
CC/STGFAA
...
ICP/MS
STGFAA
CC/ICP/MS
ICP/MS
STGFAA
ICP/MS
ICP/MS
ICP/MS
STGFAA
MDLJ
0.007
0.34
...
0.025
0.013
0.00094
0.0029
_.
0.23
0.043
0.0083
0.015
0.0039
0.012
...
0.33
0.65
0.013
1.2
0.69
0.018
0.007
0.069
0.10
ML4
0.02
1
_.
0.1
0.05
0.002
0.01
0.5
0.1
0.02
0.05
0.01
0.05
...
1
2
0.05
5
2
0.05
0.02
0.2
0.2
WQC level
achieved?1
Yes
Yes
No
Yes
Yes
Yes
Yes
No
Yes
Yes
Yes
No
Yes
Yes
No
Yes
Yes
Yes
No
No
Yes
Yes
Yes
Yes
ICP = Inductively coupled plasma Ion chrom
AES = Atomic emission spectrometry ' CC
MS = Mass spectrometry CVAF
GFAA = Graphite furnace atomic absorption spectrometry STGFAA
Ion chromatography
Chelation/concentration
Cold vapor atomic fluorescence
Stabilized temperature GFAA
Lowest of the freshwater, marine, and human health WQC promulgated by EPA for 14 states at 40 CFR Part 131 (57 FR 60848),
with hardness-dependent freshwater aquatic life criteria adjusted in accordance with 57 FR 60848 to reflect the worst case hardness
of 25 mg/L CaCOj and all aquatic life criteria adjusted in accordance with the 10/1/93 Office of Water guidance to reflect dissolved
metals criteria. A complete listing of all WQC, including total, dissolved, and levels calculated with a hardness of 25 mg/L CaCO,
and a hardness of 100 mg/L CaCO, is provided in Appendix A.
Determination of the metal is achieved if MDL is less than one-tenth the WQC level.
Method Detection Limit as determined by 40 CFR Part 136, Appendix B.
Minimum Level (ML) calculated by multiplying laboratory-determined MDL by 3.18 and rounding result to nearest multiple of 1,
2, 5, 10, 20, 50 etc. in accordance with procedures utilized by EAD and described in the EPA Draft National Guidance for the
Permitting, Monitoring, and Enforcement of Water Quality-Based Effluent Limitations Set Below Analytical Detection/Quantitation
Levels, March 22, 1994.
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X
\
Table 2 - Quality Control Requirements, Frequency, and Purpose
Required QC Test
• Instrument tuning
Calibration (CAL)
Calibration verification (VER)
Initial precision and recovery
(IPR)
Method detection limit (MDL)
and minimum level (ML)
Ongoing precision and recovery
(OPR)
Blanks
Matrix spike/matrix spike
duplicate (MS/MSD)
Field duplicate
Method of standard addition
(MSA)
Internal standardization
Spectral interference check
Serial dilutions
Frequency
Prior to calibration
Prior to sample analysis and whenever calibration cannot be verified
Immediately prior to and following the analysis of every batch of 10 or
fewer analytical samples analyzed at the same time ,
Prior to using the method for the first time and each time a modification to
the method is made
Prior to using the method and whenever there is change that will affect the
MDL and ML
Each sample batch (Sample batch size is method specific. Where hot
specified, batch size is 10.)
Equipment blank-Prior to use of any sampling equipment at a given site
Calibration blank-Immediately following each calibration verification
Laboratory (method) blank (BLK)-One method blank per sample batch
Field blank (FBK)--Every ten samples collected at a given site or at least
one per sample site, whichever is more frequent
Each batch of 10 or fewer samples from the same site
Each batch of 10 or fewer samples from the same site
As needed to assure the reliability of results for GFAA or ICP analyses
All analyses by ICP/MS (EPA Methods 200.8 and 200.10)
Prior to using the method for the first time and periodically thereafter as
indicated by instrument stability, type of samples analyzed, and expected
interferences encountered
When analyte concentration is sufficiently high (minimally a factor of 10X
the MDL after dilution)
Purpose
To assure that the instrument will produce results equivalent to instruments
in other laboratories
To establish the working range of the analytical instrument
To verify the average response or curve from the initial calibration
To establish the ability of the laboratory to generate acceptable precision and
recovery
To determine the lowest level at which the analyte can be detected with 99%
confidence that the concentration is greater than zero
To assure that the laboratory remains in control
To assure that contamination of sampling devices and apparatus for sample
collection will be detected prior to shipment to the field site
To assure that contamination of the analytical system will be detected, if
present
To assure that contamination of the analytical process will be detected, if
present
Tp assure that contamination of field samples will be detected, if present
' To determine bias caused by sample matrix effects
To measure the precision associated with sample collection, preservation,
transportation', and storage procedures, as well as with analytical procedures
To compensate for a sample constituent that enhances or depresses the
analyte signal
To correct instrument drift and other variations in the analytical process
To establish corrections for known interelement spectral interferences
To determine if a chemical or physical interference effect is present
1
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Chapter 3
Guidance for Reviewing Data
from the Analysis of Trace Metals Using
Method 1669, the QC Supplement, and the Referenced Methods
The use of guidelines provided below, or of similarly developed standardized protocols, is highly
recommended as a tool with which Regional and State permitting authorities can standardize data
inspection and acceptance procedures and minimize differences that might otherwise result between data
reviewers and/or permittees responsible for submitting data. A Data Inspection Checklist has also been
developed and is provided in the following chapter. This checklist provides a standardized format for
documenting the findings of each data inspection and an additional tool for standardizing the data review
process within a regulatory agency.
1. Purity and Traceability of Reference Standards/
The accuracy of any non-absolute empirical measurement is dependent on the reference 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 material. Method 1669, the QC
Supplement, and referenced methods all require that the standards used for calibration and other purposes
be of known purity and traceable to a reliable reference source.
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 upon request.
When analyses are conducted in a contract laboratory, such documentation should be provided to the
permittee the first time that the laboratory is employed for specific analyses and updated as needed.
2. Number of Calibration Points
The QC Supplement specifies that a minimum of three concentrations are to be used when
calibrating the instrument. (Some of the referenced methods require the use of additional calibration
points.) One of these points must be the Minimum Level (ML, see item 5), and another must be near
the upper end of the calibration range. Calibration must be performed for each target metal before any
samples or blanks are analyzed. The use of the ML as a point on the calibration curve is the principal
means by which to assure that measurements made at this quantitation level are reliable.
The data reviewer should review the points used by the laboratory to calibrate the instrument and
make certain that the calibration range encompasses the Minimum Level and that all sample and QC
measurements are within the calibration range. Samples that produce results that exceed the calibration
range should have been diluted and reanalyzed, in accordance with Section 13.2 of the QC Supplement.
The diluted sample results need only apply to those analytes that exceeded the calibration range of the
instrument. In other words, it is acceptable to use data for different analytes from different levels within
the same sample. Some flexibility may be exercised in acceptance of data that are only slightly above
(< 10%) the calibration range. Such data are generally acceptable as calculated.
December 1994
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Data Evaluation Guidance
, 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 the concentratipn at which this will occur, it is generally safe to assume that
the reported concentration above the calibrated range is a lower limit of the actual concentration.
Therefore, if the concentration above the calibration range is also above a regulatory limit, it is a virtual
certainty 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 the concentration of an analyte. The response factor (RF, calculated for external standard calibration)
or relative response factor (RRF, calculated for internal standard calibration) is the ratio of the response
of the instrument to the concentration of the analyte introduced into the instrument. Equations for
calculating RFs and RRFs are given in Sections 10.1.1 and 10.1.2 of the QC Supplement.
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 in which the linear
calibration is essentially a function of the concentration of the analyte. The advantage of the linear
calibration is that the RF or RRF represents the slope of calibration curve, simplifying calculations and
data interpretation. The QC Supplement contains specific criteria for determining the linearity of
calibration curves determined by either an internal or external standard technique. When the applicable
criterion is met, the calibration curve is sufficiently linear to permit the laboratory to use an average RF
or RRF, 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 RF
or RRF for each analyte and comparing this RSD to the specified limit. The RSD limits specified in the
QC Supplement are 15% for the RRF over the calibration range derived using the internal standard
technique and 25 % for the RF over the calibration range derived using the external standard technique.
If the RSD for any metal does not exceed the applicable 15% or 25% criterion, then an averaged RF or
RRF (as appropriate) may be used.
If the RSD indicates that the calibration is not linear, then 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 concentration. Properly maintained and operated laboratory instrumentation should have
no difficulty in meeting the linearity specifications cited above.
The laboratory must provide, the RSD results by which an independent reviewer can judge
linearity, even in instances in which the laboratory is using a calibration curve. In these instances, 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, and the data should not
be considered valid.
10 December 1994
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Data Evaluation Guidance
4. - Calibration Verification
Calibration verification involves the analysis of a single standard, typically in the middle of the
calibration range, at the beginning (and, in some cases, at the end) of each analytical shift. The
concentration of each analyte in a reference standard is determined using the initial calibration data and
compared to specifications in the method. If results are within the specifications, the laboratory may
proceed with analysis without recalibrating. The initial calibration data are then used to quantify sample
results.
Calibration verification, which is used in the QC Supplement, differs in concept and practice from
"continuing calibration", which is used in the SW-846 methods and in the Superfund Contract Laboratory
Program (CLP). In continuing calibration, a standard is analyzed and new response 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 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.
The QC Supplement requires calibration verification after every ten samples. Calibration
verification is performed by analyzing an aliquot of the mid-point calibration standard, and obtaining
results that meet the specifications contained in Table 2 of the QC Supplement. These specifications are
given for each method and metal as a percentage of the recovery of the mid-point calibration standard.
If any individual value falls outside the range given, system performance is considered unacceptable, and
the laboratory may either recalibrate the instrument or prepare a new calibration standard and make a
second attempt to verify calibration. The data reviewer should verify that each batch of 10 samples is
associated with a calibration verification that meets the required performance criteria.
5. Method Detection Limit and Minimum Level
The Minimum Level (ML) is defined in the QC Supplement as the lowest level at which the entire
analytical system gives a recognizable signal and acceptable calibration point. Therefore, the QC
Supplement requires that the calibration line or curve for each analyte encompass the ML specified in
Table 1 of that document.
The QC Supplement also requires each laboratory to perform a method detection limit (MDL)
study for each analyte in accordance with the procedures given in 40 CFR Part 136, Appendix B. The
MDL studies are conducted to demonstrate that the laboratory can achieve the MDLs listed in Table 1
of the QC Supplement. MDL determinations must be made the first time that the laboratory utilizes the
method and each time the laboratory utilizes a new instrument or modifies the method in any way.
Each MDL and ML listed in Table 1 of the QC Supplement represents the results of MDL studies
conducted by the EPA's Engineering and Analysis Division as part of its effort to validate the QC
Supplement. The MDL studies were conducted by at least one laboratory for each method and metal in
December 1994 11
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Data Evaluation Guidance
accordance with the procedure given in 40 CFR Part 136, Appendix B. The MLs shown in Table 1 were
calculated by multiplying each laboratory-determined MDL by 3.18 and rounding the result to the nearest
multiple of 1, 2, 5, 10, 20, 50, etc. in accordance with the procedures described in the EPA Draft
National Guidance for the Permitting, Monitoring, and Enforcement of Water Quality-Based Effluent
Limitations Set Below Analytical Detection/Quantitation Levels, March 22, 1994.
The QC Supplement and the Data Reporting Guidelines require the laboratory to report the
concentration of all sample results that are at or above the ML. It should be noted that this ML is a
sample-specific ML and, therefore, reflects any sample dilutions that were performed. If sample results
are reported below the ML, the data reviewer should require the responsible party to correct and resubmit
the data, or if this course of action is not possible, the reviewer should determine the sample-specific ML
and consider results below that level to be non-detects for regulatory purposes.
If sample results are reported above the ML, but are below the facility's regulatory compliance
level, then the data reviewer should consider the results to suggest that the pollutant has been detected
but is compliant with the facility's permit (assuming that all QC criteria are met). If sample results are
reported above the regulatory compliance level, the data reviewer must evaluate laboratory QC samples
in order to verify that the level of pollutant is not attributable to analytical bias. In addition, the data
reviewer must evaluate all blank sample results in order to ascertain whether the level of pollutant
detected may be attributable to contamination.
Although sample results are to be reported only if they exceed the ML, all blank results are to
be reported, regardless of the level. This reporting requirement allows data reviewers the opportunity
to assess the impact of any blank contamination on sample results that are reported above the ML.
It is important to remember that if a change that will affect the MDL is made to a method, the
MDL procedure must be repeated using the modified procedure. Changes may include alternate
digestion, concentration, and cleanup procedures, and changes in instrumentation. Alternate
determinative techniques, such as the substitution of a colorimetric technique or changes that degrade
method performance are not allowed. The data reviewer should verify that method modifications were
appropriate and were capable of producing the desired MDLs.
The procedures given in this document are for evaluation of results for determination of
regulatory compliance, and not for assessment of trends, for triggering, or for other purposes. For such
other purposes, the reporting of all results, whether negative, zero, below the MDL, above the MDL but
below the ML, or above the ML, may be of value and may be required by the permitting authority as
necessary to enforce in a particular circumstance. Dealing with the multiplicity of consequences
presented by such results, either singly or in combination, is beyond the present scope of this document.
6. Initial Precision and Recovery
The laboratory is required to demonstrate its ability to generate acceptable precision and accuracy
data using the techniques specified in the QC Supplement and the referenced method(s). This test, which
is sometimes termed the "start-up test", must be performed by the laboratory prior to the analysis of field
12 December 1994
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Data Evaluation Guidance
samples with the specified methods and prior to the use of modified versions of the method on field
samples. 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.
The test consists of spiking four aliquots of reagent water with the metals of interest at 2 - 3 times
the ML concentrations listed in Table 1 of the QC Supplement and analyzing these four aliquots. The
mean concentration (x) and the standard deviation (s) are then calculated for each analyte and compared
to the specifications in Table 2 of the QC Supplement. If the mean and the standard deviation are within
the limits, the laboratory can use the method to analyze field samples.
If the start-up test data fail to meet the specifications in the method, none of the data produced
by the laboratory can be considered to be valid. If the laboratory did not perform the start-up tests, the
data cannot be valid, unless all other QC criteria have been met and the laboratory has submitted IPR
(and associated instrument QC) data that were generated after-the-fact by the same analyst on the same
instrument. If these conditions are met, then the data reviewer may consider the data to be acceptable
for most purposes. NOTE: The inclusion of this alternative should not in any way be construed to
sanction the practice of performing IPR analyses after the analysis of field samples'. Rather, EPA believes
that demonstration of laboratory capability prior to sample analysis is an essential QC component; this
alternative is provided only as a tool to permitting authorities when data have already been collected
without the required IPR samples. Once the problem has been identified, all responsible parties are
expected to implement corrective action necessary to ensure that it is not repeated.
It is important to remember that if a change is made to a method, the IPR procedure must be
repeated using the modified procedure. If the start-up test is not repeated when these steps are modified
or added, any data produced by the modified methods cannot be considered to be valid.
7. Analysis of Blanks
Because trace metals are ubiquitous in the environment, the precautions necessary to preclude
contamination are more extensive than those required to preclude contamination when synthetic organic
compounds and other non-ubiquitous substances are determined. EPA has found that the greatest
potential for contamination of samples analyzed for trace metals has been from atmospheric input in the
field and laboratory and from inadequate cleaning of sample bottles and labware. In order to prove that
such contamination is avoided during sampling, sample transit, and analysis, Method 1669 and the QC
Supplement specify the collection and analysis of numerous blank samples. These include:
• Equipment blanks that are collected prior to the use of any sampling equipment at a given site
and provide a means for detecting contamination of sampling devices and apparatus prior to
shipment to the field site.
• Field blanks that are collected for each batch of 10 or fewer samples from the same site and
provide a means of detecting contamination that arises in the field
December 1994 . .13
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Data Evaluation Guidance
• Calibration blanks that are analyzed immediately after each calibration verification and provide
a means of detecting contamination that arises from the analytical system, and
• Laboratory (method) blanks that are analyzed for each batch of samples analyzed on a particular
instrument and provide a means of detecting contamination from the analytical process.
While the analysis of a minimum of four blank samples per site may seem to be excessive,
particularly when very few (e.g., < 5) samples are collected, EPA has found that the validity of entire
studies may be suspect when pollutants are identified in samples that are not associated with each of these
blanks. In general, it is not necessary for a facility to report the results of equipment blank analyses
unless contamination is identified in field blanks. Therefore, the permittee should obtain equipment blank
results from its cleaning facility, maintain these results on file, and provide them to the permitting
authority upon request. The data reviewer should evaluate equipment blank results only if it is necessary
to identify potential sources of contamination present in field blanks.
Controlling laboratory contamination is an important aspect of the quality assurance plan for the
equipment-cleaning facility, laboratory, and field team. Each party should maintain records regarding
blank contamination. Typically, these records take the form of a paper trail for each piece of equipment
and control charts, and they should be used to prompt corrective action by the party associated with the
contamination. For example, if records at a single site suggest that equipment blanks, laboratory blanks,
and calibration blanks are consistently clean but that field blanks show consistent levels of contamination,
then the field sampling team should re-evaluate their sample handling procedures, identify the problem,
and institute corrective actions before collecting additional samples. Similarly, equipment cleaning
facilities and laboratories should utilize the results of blank analyses to identify and correct problems in
their processes.
Unfortunately, it is often too late for corrective action if data are received that suggest the
presence of uncontrolled contamination that adversely affects the associated data. The exception to this
rule is the case in which the field and equipment blanks show no discernable levels of contamination,
contamination is detected in the laboratory or calibration blanks, sample holding times have not expired,
and sufficient sample volume remains to allow the laboratory to identify and eliminate the source of
contamination and reanalyze the associated sample(s). In all other cases, the reviewer must exercise one
of several options listed below when making use of the data.
• If a contaminant is present in a blank but is. not present in a sample, then there is little need for
concern about the sample result. (It may be useful, however, to occasionally review the raw data
for samples without the contaminant to ensure that the laboratory did not edit the results, for this
compound.)
• If the sample contains the contaminant at levels of at least 10 times that in the blank, then the
likely contribution to the sample from the contaminant in the sample is at most 10%. Since most
of the methods in question are no more accurate than that level, the possible contamination is
negligible, and the data can be considered to be of acceptable quality.
14 December 1994
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Data Evaluation Guidance
• ' If the sample contains the contaminant at levels of at least 5 times but less than 10 times the blank
result, the numerical result in the sample should be considered an upper limit of the true
concentration, and data users should be cautioned when using such data for enforcement
purposes.
• If the sample contains the contaminant at levels below 5 times the level in the blank, the sample
data are suspect unless there are sufficient data from analyses of multiple blanks to perform a
statistical analysis proving the significance of the analytical result. Such statistical analyses are
beyond the scope of this guidance.
• If blank contamination is found in some types of QC samples but not others (e.g., only in the
laboratory blank but not in the field blank), the data user should apply the guidelines listed above,
but may also use this information to identify the source of contamination and take corrective
actions to prevent future recurrences.
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. Field blanks are associated with
each group of field samples collected from the same site. Calibration blanks are associated with samples
by the date and time of analysis on a specific instrument. Laboratory (method) blanks are associated with
each batch of 10 samples prepared and digested in accordance with a particular method during a single
shift. If the reviewer cannot associate a batch of samples with a given blank, the reviewer should request
this association from the laboratory so that the results for the samples can be validated.
The second difficulty involves samples that have been diluted. The dilution of the sample with
reagent water 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
stated above, the concentration of the sample is compared to the blank results multiplied by the dilution
factor of the sample. For instance, if 1.2 ppb of a contaminant is found in the blank, and the associated
sample was diluted by a factor of six relative to the extract from the blank prior to analysis, then the
diluted sample result would have to be greater than 1.2 x 6 x 10 or 72 ppb to be acceptable. Diluted
sample results between 36 and 72 ppb would be considered an upper limit of the actual concentration,
and diluted sample results that were less than 36 ppb would be considered unacceptable in the absence
of sufficient blank data to statistically prove the significance of the result.
In most cases, the practice of subtracting the concentration reported in the blank from the
concentration in the sample is not recommended as a tool to evaluate sample results associated with blank
data. One of the most common problems with this approach is that blank concentrations are sometimes
higher than one or more associated sample results, yielding negative results.
Blank contamination is usually highly variable, and this variability must be accounted for in order
for blank-subtraction to be reliable. A usual solution to this problem is to establish the concentration in
blanks over time and set the limit on the level above which blank-subtraction may be performed at two
standard deviations above the average blank level. However, this approach requires a large data set to
be reliable. Most compliance data are received as a self-contained data set with QC data limited to the
December 1994 15
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Data Evaluation Guidance
analytical batch in which the samples were analyzed. As a result, data evaluators are usually not privy
to blank data over time and cannot therefore perform reliable blank-subtraction using this statistical
approach. Further, requiring submission of long-term blank data may unnecessarily complicate the data
reporting process because a determination would need to be made as to which data should be included
or excluded. Using the ten times rule above provides a more appropriate means of evaluating the results
and does not require the reviewer to alter results reported by the laboratory.
Nearly all of the methods provided in the QC Supplement are capable of producing MDLs that
are at least 10 times lower than the lowest water quality criteria (WQC) published in the National Toxics
Rule. Since most discharge permits require monitoring at levels that are comparable to or higher than
the WQC published in the National Toxics Rule, EPA believes that, in nearly all cases, laboratories
should be capable of producing blank data that are at least 10 times less than the regulatory compliance
level. It should also be noted that laboratories cannot be held accountable for contamination that is
present in field blanks but not present in laboratory blanks; in such'cases the sampling crew should take
corrective measures to eliminate the source of contamination during their sample'collection and handling
steps.
8. Ongoing Precision and Recovery
The QC Supplement requires laboratories to prepare and analyze an "ongoing precision and
recovery" (OPR) sample with each batch of up to 10 samples started through the extraction process on
the same twelve hour shift. This OPR sample is identical to the aliquots used in the IPR analyses (see
Item 6), and the results of the OPR are used to ensure that laboratory performance is in control during
the analysis of the associated batch of field samples.
The data reviewer must verify that the OPR sample has been run with each sample batch and that
the applicable recovery criteria in Table 2 of the QC Supplement have been met. If the recovery criteria
have not been met, the reviewer may use the following guidelines when making use of the data:
• If the concentration of the OPR is above method specifications but that analyte is not detected in
an associated sample, then it unlikely that the sample result is affected by the failure in the OPR.
• If the concentration of the OPR is above method specifications and that analyte is detected in the
sample, then the numerical sample result may represent an upper limit of the true concentration,
and data users should be cautioned when using the data for enforcement purposes.
• If the concentration of the OPR is below method specification but that analyte is detected in an
associated sample, then the sample result may represent the lower limit of the true concentration
for that analyte. , ' , •
• If the concentration of the OPR is below method specification and that analyte is not detected in
an associated sample, then the sample data are suspect and cannot be considered valid for
regulatory compliance purposes.
16 December 1994
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Data Evaluation Guidance
' If the OPR standard has not been run, there is no way to verify that the laboratory processes were
in control. In such cases, a data reviewer may be able to utilize the field sample data by examining the
matrix spike recovery results (see item 9), the IPR results, OPR results from previous and subsequent
batches, and any available historical data from both the laboratory and the sample site. If the matrix
spike results associated with the sample batch do not meet the performance criteria in Table 2 of the QC
Supplement, then the results for that set of samples cannot be considered valid. If the laboratory's IPR
results and the matrix spike results associated with the sample batch in question meet the all applicable
performance criteria in Table 2 of the QC Supplement, then the data reviewer may be reasonably
confident that laboratory performance was in control during field sample analysis. This level of
confidence may be further increased if there is a strong history of both laboratory performance with the
method and method performance with the sample matrix in question, as indicated by additional OPR and
matrix spike data collected from the laboratory and samples from the same site.
9. Precision and Recovery of Matrix Spike and Matrix Spike Duplicate Compounds
The QC Supplement and the referenced methods require that laboratories spike the analytes of
interest into duplicate aliquots of at least one sample from each group of ten samples collected from a
single site. The first of these spiked sample aliquots is known as the matrix spike sample; the second is
known as the matrix spike duplicate. These.spiked sample aliquots are used to determine if the method
is applicable to the sample matrix in question. The analytical procedures described in the QC Supplement
and the referenced methods are applicable to the determination of metals at concentrations typically found
in ambient water samples and certain treated effluents (e.g., the part-per-trillion to low part-per-billion
range). These methods may not be applicable to marine samples and many effluent and in-process
samples collected from industrial dischargers. Therefore, it is important to evaluate method performance
in the sample matrix of interest.
In evaluating matrix spike sample results, it is important to examine both the precision and
accuracy of the duplicate analyses. Precision is assessed by examining the relative percent difference
(RPD) of the concentrations found in the matrix spike and matrix spike duplicate samples, and comparing
the RPD to the acceptance criteria specified in the referenced method. If an RPD acceptance criteria is
not specified in the referenced method, the QC Supplement requires the RPD results to be less than 20%.
If the RPD of a matrix spike/matrix spike duplicate pair exceeds the applicable criterion, then the method
cannot be considered to be applicable to the sample matrix, and none of the associated sample data can
be accepted for regulatory compliance purposes.
If RPD criteria are met, the method is considered to be capable of producing precise data in these
samples, and the data reviewer must then verify that the method is capable of producing accurate data..
Accuracy is assessed by examining the recovery of compounds in the matrix spike and matrix spike
duplicate samples. If the recovery of the matrix spike and duplicate are within the limits specified in the
method or the QC Supplement, 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.
December 1994 17
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Data Evaluation Guidance
, 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 calibration verification standards and OPR samples. * If the results
for either of these analyses are not within the specified range, then the analytical system or process must
be corrected. After the performance of the analytical system and processes have been verified (through
the successful analysis of CCV and OPR samples), the spike sample analysis should be repeated. If the
recovery of the matrix spike and duplicate are within the range specified in Table 2 of the QC
Supplement, then the method and laboratory performance can be considered acceptable. If, however, the
recovery of the matrix spike does not meet the specified range, the laboratory should attempt to further
isolate the metal and repeat the test. If recovery of the metal remains outside the acceptance criteria, the
data reviewer may apply the. following guidelines when attempting to make use of the data:
• If the recovery of the matrix spike and duplicate are above method specifications but that metal
is not detected in an associated sample or is detected below the regulatory compliance limit, then
it unlikely that the sample result is affected by the failure in the matrix spike.
• If the recovery of the matrix spike and duplicate are above method specifications and that metal
is detected in an associated sample above the regulatory compliance level, then the sample result
may represent the upper limit of the true concentration, and the data should not be considered
valid for regulatory compliance purposes.
• If the concentration of the matrix spike and duplicate are below method specifications but that
metal is detected in an associated sample, then the sample result may represent the lower limit
of the true concentration for that metal. If the metal was detected in the sample at a
concentration higher than the regulatory compliance limit, then it is unlikely that the sample result
is adversely affected by the matrix. If, however, the metal was detected below the regulatory
compliance limit, the data should not be considered valid for regulatory compliance purposes.
10. Statements of Data Quality for Spiked Sample Results
The QC Supplement specifies that after the analysis of five spiked samples of a given matrix type,
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 the percent
recovery for the analyte. The statements of data quality should then be updated by the laboratory after
each five to ten subsequent spiked sample analysis.
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
selenium is 10 ppb, and the statement of data quality for selenium is 84% ±25% (i.e., the mean
18 December 1994
I2.S
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Data Evaluation Guidance
recovery is 84 % and the standard deviation of the recovery is 25 %), then the true value for selenium will
be in the range of 9.4 - 14.4 ppb, with 95% confidence. This range is derived as follows:
Lower Limit = [(10 + .84) - (10 x .25)] ~ [11.9 - 2.5] = 9.4 ppb
Upper Limit = [(10 -s- .84) + (10 x .25)] = [11.9 + 2.5] = 14.4 ppb
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. The lack of a data quality statement 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.
11. Statements of Data Quality for Spiked Reagent Water Results
In addition to statements of data quality for results of analyses of the compounds spiked into field
samples, the QC Supplement requires that statements of data 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
results of spiked field samples. Ideally, the two statements of data quality would be the same. Any
difference is attributable to either random error or sample matrix effects.
12. Field Duplicates
Method 1669 requires the collection of at least one field duplicate for each batch of field samples
collected from the same site. The field duplicate provides an indication of the overall precision associated
with entire data gathering effort, including sample collection, preservation, transportation, storage, and
analysis procedures. The data reviewer should examine field duplicate results and use the following
equation to calculate the relative percent difference between the duplicate and its associated samples.
RPD -
(D1+D2)
where:
Dl = concentration of the analyte in the MS sample
D2 = concentration of the analyte in the MSD sample
December 1994 - 19
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Data Evaluation Guidance
If the analyte of interest was not detected in either replicate of the field sample, then the RPD
will be zero. If the analyte was detected in each field sample replicate, but the results are highly
disparate (indicated by a large RSD), the reviewer should apply the following guidelines when making
use of the data:
• If the analyte was detected in each replicate and at similarly variable concentrations in the blank
samples, then the field sample variability may be attributable to variable contamination, and the
data may not be valid for regulatory compliance purposes.
• If the analyte was detected in each replicate at a concentration well above the regulatory
compliance level, but was not detected in the associated blank samples, then it is likely that the
sample results are not adversely affected.
Ideally, the RPD between field duplicates and MS/MSD samples will be identical. Any difference
between the two is attributable to variability associated with the field sampling process.
20 December 1994
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Chapter 4
Data Inspection Checklist
The following pages contain a data inspection checklist that may be used by data reviewers,
laboratory personnel, and other parties to document the results of each data inspection in a standardized
format.
December 1994 21
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Data Inspection Checklist
Summary Information
1.. Name of Reviewer:
Title:
Required Samples •
Sample Results Provided
Sample Location or Sample ID
Analyte(s)
Sample Location or Sample ID
Analyte(s)
2. Method Used:
3. Total No. of analytical shifts per instrument (determined from analysis run log):
Instrument
No. of Shifts
4. Total No. of CCVs Required:
(one for each 10 samples after the
first 10 samples on each instrument)
5. Total No. of CCBs Required:
(one for each CCV)
6. Total No. of Field Blanks Required:
(one per site or per 10 samples, whichever is more
frequent).
7. Total no. of Lab Blanks Required:
(one per batch* per method/instrument)
8. Total no. of OPR analyses Required:_
(one per batch per method/instrument)
9. Total no. of MS/MSD samples Required:
(one per 10% per matrix per site)
Total No. of CCVs Reported:
Total No. of CCBs Reported:
Total No. of Field Blanks Reported:
Total No. of Lab Blanks Reported:
Total No. of OPR Analyses Reported:
Total No. of MS/MSD samples Reported^
10. Total no. Field Duplicates Required:
(one per 10 samples per site)
11. Total no. of MDL results required:
(one per method and per analyte)
Total No. of Field Duplicates Reported:
Total No. of MDL Results Reported:
22
December 1994
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Data Inspection Checklist
12.
»
a.
b.
c.
Initial Calibration
Was a multiple-point initial calibration performed"? Dyes Dno
Were all sample concentrations reported within the calibration .range? Dyes Ono
If no. list method and analytes for which initial calibration was not performed or which
exceeded the calibration range.'
Analvte No ICAL (Y/N1 Exceeded ICAL Ranee (Y/N)
d.
e.
Did the initial calibration meet linearity criteria?
If no, was a calculation curve used to calculate sample concentrations?
Dyes Dno
* A three point (minimum) initial calibration should be performed for each analyte; if the RSD of the mean RRF is less than 15%,
or if the RSD of the mean RF is less than 25%, then the averaged RRF or RF, respectively, may be used for that analyte.
13. Method Detection Limit (MDL)/Minimum Level (ML)
a. Did the laboratory demonstrate their ability to achieve the required MDL? Dyes Dno
b. Did the initial calibration range encompass the ML? Dyes Dno
c. Were all field samples detected below the ML reported as non-detects? Dyes Dno
d. If the answer to item a, b, or c above was "no", describe problem:
December 1994
23
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Data Inspection Checklist
14. Initial Calibration Verification (ICV)/Initial Calibration Blanks (ICB):
a. Was an ICV run prior to field samples? Dyes Dno
»
b. Were ICV results within the specified windows? Dyes Dno
c. Was the ICV followed by an ICB? Dyes Dno
d. Was the ICB free from contamination? Dyes Dno
e. If any item in a - d above was answered "no", list problems below:
#
Analvte Failed ICV Recovery Concentration Detected in ICB Affected Samples
15. Initial Precision and Recovery (IPR)
a. Were IPR data reported for each analyte? Dyes Dno
b. Did all IPR aliquots meet required recovery criteria (x)? Dyes Dno
c.- Did the standard deviation (s) of each IPR series meet the required criterion? Dyes Dno
d. If any item in a - d above was answered "no", document problem below.
Analvte Ave. Result Reported (X) RSD Reported Affected Samples
16. Ongoing Precision and Recovery (OPR)
a. Was OPR data reported for analyte, instrument, and batch? Dyes Dno
b. Did all OPR samples meet.required recovery criteria (x)? Dyes Dno
c. If item a or b above was answered "no", document problem below.
Analvte OPR Recovery (X) Reported Shifts Missing OPR Affected Samples
24 December 1994
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Data Inspection Checklist
17. Continuing Calibration Verification (CCV)/Continuing Calibration Blank (CCB)
a., Were CCVs run prior to each batch of 10 samples on each instrument? Dyes Dno
b. Were all CCV results within the specified windows? Dyes Dno
c. Was each CCV followed by a CCB? Dyes Dno
d. Was each CCB free from contamination? Dyes Dno
e. If any item in a - d above was answered "no", list problems below:
Analvte Affected Samples Shift Missing CCV/CCB Failed CCV/CCB ID
18. Laboratory (Method) Blanks
a. Was a method blank analyzed for each instrument & sample batch?
b. Was each method blank demonstrated to be free from contamination?
c. If the answer to item a or b was "no", document problems below.
Analvte Affected Samples Blank Concentration Reported
Dyes Dno
Dyes Dno
Dyes Dno
Shift Missing MB
19. Field Blanks
a. Was a field blank analyzed for each 10 samples per site?
b. Was each field blank demonstrated to be free from contamination?
c. If the answer to item a or b was "no", document problems below.
Analvte Affected Samples Blank Concentration Reported
Dyes Dno
Dyes Dno
Dyes Dno
Shift Missing FB
December 1994
25
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Data Inspection Checklist
20.
•a.'
b.
c.
d.
MS/MSD Results
Were appropriate number of MS/MSD pairs analyzed? Dyes Dno
Were all MS/MSD recoveries within specified windows? Dyes Dno
Were all RPDs within the specified window? Dyes Dno
Was appropriate corrective action (e.g., MSA for.GFAA, serial dilution
for ICP) employed on affected samples? Dyes Dno
If the answer was "no" to items a - d above, document affected samples:
Analyte MS % R
MSP % R
MS/MSD RPD Affected Samples
21. Additional Information
a. Were Instrument Tune Data Provided? Dyes Dno
b. Were equipment blanks demonstrated to be free from contamination? Dyes Dno
c. Were statements of data quality provided? Dyes Dno
d. Did field duplicate demonstrate acceptable precision? Dyes Dno
I3C
26
December 1994
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APPENDIX A
Analytical Laboratories
EPA Office of Water, Engineering & Analysis Division
-------
Analytical Laboratories
During the course of its efforts to develop guidance for the analysis of trace metals at ambient water
quality levels, the EPA Engineering and Analysis Division's Analytical Methods Staff has identified
several laboratories that are currently determining certain trace metals at ambient water quality levels.
These laboratories are identified below for informational purposes only. This does not represent an
exhaustive list, nor does it constitute an EPA endorsement of any laboratory appearing on the list.
Axis Environmental Systems, Ltd.
P.O. Box 2219
2045 Mill Road
Sydney, BC Canada V8L 3S8
Contact: Mary McFarland
Phone: 604/656-0881
Battelle/Marine Sciences Laboratory
1529 West Sequim Bay Road
Sequim, WA 98382
Contact: Eric Crecelius
Phone: 206/683-4151
Battelle Ocean Sciences
397 Washington Street
Duxbury, MA 02332
Contact: Dion Lewis; Carlton Hunt
Phone: 617/934-0571
University of California/Santa Cruz
Environmental Toxicology
Santa Cruz, CA 95064
Contact: Russell Flegal; Kenneth Bruland
Phone: 408/459-2093
University of Connecticut
Department of Marine Sciences
1084 Shennecossett Road
Groton, CT 06340-6097
Contact: William Fitzgerald
Phone: 203/446-1020
Department of Oceanography
Florida State University
Tallahassee, Florida 32306-3048
Contact: Bill Landing
Phone: 904/644-6037
College of Marine Studies
University of Delaware
Lewes, DE 19538
Contact: Thomas M. Church
Phone: 302/645^253
Frontier GeoSciences
414 Pontius North
Seattle, WA 98109
Contact: Nicholas Bloom
Phone: 206/622-6960
Old Dominion University
Department of Oceanography
Norfolk, VA 23529
Contact: Greg Cutter
Phone: 804/683-4285
Texas A&M University at Galveston
Department of Marine Sciences
5007 Avenue U
Galveston, TX 77553-1675
Contact: Gary Gill
Phone: 409/740-4710
Texas A&M University
Department of Oceanography
College Station, TX 77843-3146
Contact: Paul Boothe
Phone: 409/845-5137
Skidaway Institute of Oceanography
P.O. Box 13687
Savannah, Georgia 31416
Contact: H.L. Windom
Phone: 912/598-2490
Green Meadows Laboratory
363 W. Drake Road
Fort Collins, CO 80526
Contact: Rod Skogerboe
Phone: 303/223-9828
Research Triangle Institute
Institute Drive, Building 6
Research Triangle Park, NC 27709
Contact: Peter Grohse
Phone: 919/541-6190
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APPENDIX B
Office of Water Interim Guidance Concerning the
Collection of Metals Data at WQC Levels
(November 8, 1994)
EPA Office of Water, Office of Science & Technology
-------
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, O.C. 20460
OFFICE OF
WATER
. NOV 8 1994
MEMORANDUM
SUBJECT: Interim Guidance Concerning the Collection of Metals
Data at WQC Levels
TO: Water Division Directors
FROM: Tudor Davies, Director
Office of Science and Technology
SUMMARY
As we discussed during our last meeting, the Office of
Science and Technology's Engineering and Analysis Division (EAD)
has been engaged in the development of guidance to support the
Office of Water's policy regarding the implementation of water
quality criteria (WQC) for metals. These efforts include the
development of sampling and analysis methods, and of data
reporting and review guidelines. Draft sampling and analysis
methods have been completed and have been subjected to limited
peer review within and outside of the Agency. These methods are
currently undergoing validation and more extensive peer review.
Draft data reporting guidelines have also been developed and will
serve as a cornerstone for the forthcoming data review
guidelines. A schedule of projected completion dates for each of
these efforts is provided as Attachment 1 to this memo. Copies
of the draft sampling method and the quality control supplement
are also attached.
During the development of the methods and guidance described
above, EAD has fielded numerous questions from Regional and State
offices regarding interim measures that these offices can take to
maximize the quality of trace metals data that they are currently
gathering or will be gathering in the near future. The remainder
of this memorandum addresses these questions and is intended to
serve as interim guidance to Regional and State permitting staff
until completion and issuance of the guidance and methods cited
above.
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contain* « tout 50% nKydod fib*
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-------
IHTERZM GUIDANCE
The following is a list of activities or areas that should
assist Regional and State offices in obtaining reliable metals
data. Please hdte that, in some instances, the information that
is referenced is contained in the draft sampling and analysis
guidance documents that are provided in Attachment 2. The Office
of Science and Technology emphasizes that the information in this
memo and in the draft guidance is guidance. It is intended to
assist Regional and State personnel and does not constitute
formal Agency policy at this time.
Awareness; Two of the most important factors in avoiding/
reducing sample contamination are (1) an awareness of potential
sources of contamination, and (2) strict attention to work being
performed. For this reason, we recommend that all permitting and
monitoring staff become aware of the activities necessary to
prevent sample contamination by reading the draft EAD sampling
and analytical guidance and the technical literature on
determination of metals at trace levels. In order to minimize
the cumulative effects of contamination from multiple sources,
sample and laboratory staff should be instructed to implement as
many aspects of the guidance as are feasible in their current
activities. Guidance aspects that EAD believes may be most
critical in reducing or minimizing the potential for
contamination.include the following:
Preparing samples and standards in a controlled area:
Exposure of samples, standards, and blanks to the atmosphere
is one of the most common ways of introducing contamination.
Therefore, samples and standards should be prepared in a
controlled area. Preferably, this controlled area is a
clean room, a clean bench, or a glove box.
Cleaning sample bottles and labware: EAD has found that all
researchers performing trace metals analyses agree on the
need for extensive procedures for bottle cleaning. While
the actual cleaning procedures used by researchers vary
(from boiling in nitric acid for 8 hours, to soaking in 50
°C nitric acid for two weeks followed by storage filled with
dilute hydrochloric acid), all procedures used are exten-
sive. We highly recommend that such extensive procedures be
implemented in any interim data gathering efforts.
Wearing gloves and changing gloves when a potential source
of contamination has been touched: Although not absolutely
necessary, the discipline of wearing gloves brings with it
an awareness that samples can be contaminated. Further, the
use of gloves is simple, inexpensive, and may serve to
reduce the cumulative effects of contamination to levels
that will not have an adverse impact on data quality.
Using metal"free apparatus: In addition to inspecting all
apparatus that the sample will contact for the presence of
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metals, procedures should be in place to make sure that the
surfaces that the sample will touch will not contact metals.
Analyzing Blanks; Results of the analysis of equipment blanks
will inform the equipment cleaning facility that the cleaning
processes are in control. These results should be used to
facilitate corrective actions prior to sample collection.
Similarly, results of analysis of laboratory blanks will inform
the analyst and the laboratory quality assurance officer (QAO)
that laboratory operations are in control. These results should
be used to facilitate corrective actions prior to completion of
sample analysis. Finally, analysis of field and laboratory
blanks will enable the data user to assess the source, extent,
and impact of contamination (if any).
QC Data; The ability to assess data quality is directly linked
to the presence of QC data. Therefore, we highly recommend that,
as a minimum requirement, all new data gathering efforts include
the collection, analysis, and evaluation of QC samples described
in the draft guidance documents. These QC samples include
equipment, field, laboratory, and calibration blanks,
demonstrations of instrument calibration and calibration
verification, demonstrations of initial and ongoing laboratory
precision and accuracy through the analysis of IPR and OPR (or
equivalent) samples, and demonstration of method precision and
accuracy (through the analysis of matrix spike/matrix spike
duplicate samples).
Many EPA methods provide either performance data or
performance criteria for certain QC elements. Unless program-
specific performance criteria have been developed for the data in
question, data users should review the QC data against the
criteria provided in the QC Supplement included with this
guidance. These criteria were developed based on data from
determination of the analytes in multiple matrices, and are an
attempt to reflect the somewhat additional variability that can
be expected when trace metals are determined at or near ambient
water quality criteria levels. If the QC Supplement does not
contain QC criteria, and if program-specific criteria have not
been developed, OST recommends that the data user evaluate QC
data against criteria provided in an alternate EPA method that
utilizes similar analytical procedures.
Regardless of the specifications contained in the method,
OST recommends that data users adhere to the following guidelines
concerning the presence of contamination in blank samples:
Ideally, all blank samples should be free from contamination
above the Method Detection Level (MDL) or estimated MDL for
the analyte in the method.
If blank contamination is present, but it is present at a
level that is at least 10 times less than the levels in
associated field samples, we believe that the field sample
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data are of acceptable quality.
If blank contamination is present, but it is present at a
. level that is between 5 and 10 tines less than the levels in
the associated field samples, we believe that the sample
data may be biased high, and data users should be cautioned
when using such data for enforcement purposes.
If blank contamination is present, but is present at a level
that is between 1 and 5 times less than the level in the
sample, data should be suspect unless there are sufficient
data from analyses of multiple blanks to perform a
statistical analysis proving the significance of the
analytical result. Such statistical analyses are beyond the
scope of this guidance.
If blank contamination is found in some types of QC samples
but not others (e.g., only in the laboratory blank but not
in the field blank), the data user should apply the
guidelines listed above, but may also use this information
to identify the source of contamination and take corrective
actions to prevent future recurrences.
If supporting QC data are not present and cannot be
obtained, the data user must recognize that the analytical result
may be valid but that validity cannot be proved, and that no
statement can be made regarding data quality. An exception to
this situation is one in which long-term monitoring data are
available and the long term data are associated with QC data that
demonstrate data validity. If this circumstance exists, and if a
single result is missing associated QC data but is statistically
consistent with the validated long-term data, the data user may
reasonably make the assumption that the single value is valid.
Note, however, that the presence of unvalidated long-term
monitoring data does not pr.ovide any level of certainty. Long-
term data may be continuously biased by contamination or other
failures if the data are continuously generated using the same
procedures. Without QC data to support the long-term monitoring
data, there is no way to assess long-term data validity.
If you have any questions regarding the information contained in
this memo, please contact Bill Telliard of HAD at 202/260-7134.
Attachments
cc: Environmental Services Division Directors, RO I - X
Enforcement Division Directors, OECA
Tom O'Farrell
Sheila Frace
Betsy Southerland
Margaret Stasikowski
Mike Cook
Cynthia Dougherty
Dana Minerva
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Attachment 1
Projected Schedules and Activities for Development of
EAD Trace Metals Guidance
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Engineering and Analysis Division
Analytical Methods Staff
Projected Schedules and Activities for Development of Trace Metals Guidance
October 31, 1994
Sampling Guidance
• A draft sampling method was completed in January 1994; this version and subsequent revisions (now
referred to as EPA Method 1669) have been subjected to limited peer review within and outside the
Agency. The most recent draft is undergoing more extensive peer review.
• Final revision of sampling guidance incorporating clean techniques from USGS and other experts will be
completed by December 1994.
• Development of guidance for effluent sampling will be completed by January 1995.
Analytical Methods
• New analytical methods for determination of most metals at WQC levels will be available by the end of
December 1994.
Validation of Quality Control Supplement for Determination of Metals at Ambient Water Quality
Criteria Levels Using EPA Methods is underway for 10 metals; revision of the QC Supplement
to reflect the validation study will be completed by December 1994.
New EPA methods that incorporate the procedures in the final version of the QC Supplement will
be available by March 1995.
• Methods are currently under development for
Arsenic, Chromium (III) and Mercury
Draft methods will be completed by December 1994
Method validation activities will be conducted in early FY95
• Interlaboratory studies of all new methods will be initiated in FY95
Data Reporting and Data Review Guidance
• Draft data reporting guidelines have been developed to serve as the foundation for draft data review
guidance. The data reporting guidelines are designed to capture all data elements necessary to assess and
define data quality.
• Data review guidelines are scheduled for completion in FY95.
Other Activities
• An ORD report evaluating clean rooms will be released in October 1994. EAD will issue guidance on
upgrading existing laboratory facilities for clean techniques in December.
• A Trace Metals Workshop for State and Regions is scheduled to be held in conjunction with the Norfolk
Conference in May 1995.
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APPENDIX C
Office of Water Policy and Technical Guidance on
Interpretation and Implementation of
Aquatic Life Metals Criteria
(October 1, 1993)
EPA Office of Water
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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON. D.C. 20460
OCT 1 693
OFFCEOF
WATER
MEMOR A NDUM
SUBJECT: Office of Water Policy and Technical Guidance on Interpretation and
Implementation of Aquatic Life Metals Criteria
FROM: Martha G. Prothro
Acting Assistant Administrator for Water
TO: Water Management Division Directors
Environmental Services Division Directors
Regions l-X
Introduction
The implementation of metals criteria is complex due to the site-specific nature of
metals toxicity. We have undertaken a number of activities to develop guidance in this area,
notably the Interim Metals Guidance, published May 1992, and a public meeting of experts
held in Annapolis, MD, in January 1993. This memorandum transmits Office of Water
(OW) policy and guidance on the interpretation and implementation of aquatic life criteria for
the management of metals and supplements my April 1, 1993, memorandum on the same
subject. The issue covers a number of areas including the expression of aquatic life criteria;
total maxirflum daily loads (TMDLs), permits, effluent monitoring, and compliance; and
ambient monitoring. The memorandum covers each in turn. Attached to this policy
memorandum are three guidance documents with additional technical details. They are:
Guidance Document on Expression of Aquatic Life Criteria as Dissolved Criteria
(Attachment #2), Guidance Document on Dynamic Modeling and Translators (Attachment
#3), and Guidance Document on Monitoring (Attachment #4). These will be supplemented
as additional data become available. (See the schedule in Attachment #1.)
Since metals toxicity is significantly affected by site-specific factors, it presents a
number of programmatic challenges. Factors that must be considered in the management of
metals in the aquatic environment include: toxicity specific to effluent chemistry; toxicity
specific to ambient water chemistry; different patterns of toxicity for different metals;
evolution of the state of the science of metals toxicity, fate, and transport; resource
limitations for monitoring, analysis, implementation, and research functions; concerns
regarding some of the analytical data currently on record due to possible sampling and
analytical contamination; and lack of standardized protocols for clean and ultraclean metals
analysis. The States have the key role in the risk management process of balancing these
factors in the management of water programs. The site-specific nature of this issue could be
perceived as requiring a permit-by-permit approach to implementation. However, we believe
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that this gtvdance can be effectively implemented on a broader level, across any waters with
roughly the same physical and chemical characteristics, and recommend that we work with
the States with that perspective in mind.
Expression of Aquatic Life Criteria
o Dissolved vs. Total Recoverable Metal
A major issue is whether, and how, to use dissolved metal concentrations ("dissolved
metal") or total recoverable metal concentrations ("total recoverable metal") in setting State
water quality standards. In the past, States have used both approaches when applying the
same Environmental Protection Agency (EPA) criteria numbers. Some older criteria
documents may have facilitated these different approaches to interpretation of the criteria
because the documents were somewhat equivocal with regards to analytical methods. The
May 1992 interim guidance continued the policy that either approach was acceptable.
It is now the policy of the Office of Water that the use of dissolved metal to set and
measure compliance with water quality standards is the recommended approach, because
dissolved metal more closely approximates the bioavailable fraction of metal in the water
column than does total recoverable metal. This conclusion regarding metals bioavailability is
supported by a majority of the scientific community within and outside the Agency. One
reason is that a primary mechanism for water column toxiciry is adsorption at the gill surface
which requires metals to be in the dissolved form.
The position that the dissolved metals approach is more accurate has been questioned
because it neglects the possible toxicity of paniculate metal. It is true that some studies have
indicated that paniculate metals appear to contribute to the toxicity of metals,, perhaps
because of factors such as desorption of metals at the gill surface, but these, same studies
indicate the toxicity of paniculate metal is substantially less than that of dissolved metal.
Furthermore, any error incurred from excluding the contribution of paniculate metal
will generally be compensated by other factors which make criteria conservative. For
example, metals in toxicity tests are added as simple salts to relatively clean water. Due to
the likely presence of a significant concentration of metals binding agents in many discharges
and ambient waters, metals in toxiciry tests would generally be expected to be more
bioavailabile than metals in discharges or in ambient waters.
If total recoverable metal is used for the purpose of water quality standards,
compounding of factors due to the lower bioavailability of paniculate metal and lower
bioavailability of metals as they are discharged may result in a conservative water quality
standard. The use of dissolved metal in water quality standards gives a more accurate result.
However, the majority of the participants at the Annapolis meeting felt that total recoverable
measurements in ambient water had some value, and that exceedences of criteria on a total ^
recoverable basis were an indication that metal loadings could be a stress to the ecosystem^
particularly in locations other than the water column.
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The reasons for the potential consideration of total recoverable measurements include
risk management considerations not covered by evaluation of water column toxicity. The
ambient water quality criteria are neither designed nor intended to protect sediments, or to
prevent effects due to food webs containing sediment dwelling organisms. A risk manager,
however, may consider sediments and food chain effects and may decide to take a
conservative approach for metals, considering that metals are very persistent chemicals. This
conservative approach could include the use of total recoverable metal in water quality
standards. However, since consideration of sediment impacts is not incorporated into the
criteria methodology, the degree of conservatism inherent in the total recoverable approach is
unknown. The uncertainty of metal impacts in sediments stem from the lack of sediment
criteria and an imprecise understanding of the fate and transport of metals. EPA will
continue to pursue research and other activities to close these knowledge gaps.
Until the scientific uncertainties are better resolved, a range of different risk
management decisions can be justified. EPA recommends that State water quality standards
be based on dissolved metal. (See the paragraph below and the attached guidance for
technical details on developing dissolved criteria.) EPA will also approve a State risk
management decision to adopt standards based on total recoverable metal, if those standards
are otherwise approvable as a matter of law.
o Dissolved Criteria
In the toxicity tests used to develop EPA metals criteria for aquatic life, some fraction
of the metal is dissolved while some fraction is bound to paniculate matter. The present
criteria were developed using total recoverable metal measurements or measures expected to
give equivalent results in toxicity tests, and are articulated as total recoverable. Therefore,
in order to express the EPA criteria as dissolved, a total recoverable to dissolved correction
factor must be used. Attachment 82 provides guidance for calculating EPA dissolved.criteria
from the published total recoverable criteria. The data expressed as percentage metal
dissolved are presented as recommended values and ranges. However, the choice within
ranges is a State risk management decision. We have recently supplemented the data for
copper and are proceeding to further supplement the data for copper and other metals. As
testing is completed, we will make this information available and this is expected to reduce
the magnitude of the ranges for some of the conversion factors provided. We also strongly
encourage the application of dissolved criteria across a watershed or waterbody, as
technically sound and the best use of resources.
o Site-Specific Criteria Modifications
While the above methods will correct some site-specific factors affecting metals
toxicity, further refinements are possible. EPA has issued guidance (Water Quality
Standards Handbook, 1983; Guidelines for Deriving Numerical Aquatic Site-Specific Water
Quality Criteria by Modifying National Criteria, EPA-600/3-H4-099, October 1984) for three
site-specific criteria development methodologies: recalculation procedure, indicator species
procedure (also known as the water-effect ratio (WER)) and resident species procedure.
Only the first two of these have been widely used.
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In the National Toxics Rule (57 FR 60848, December 22, 1992), EPA identified the
WER as an optional method, for site-specific criteria development for certain metals. EPA
committed in the NTR preamble to provide guidance on determining the WER. A draft of
this guidance has been circulated to the States and Regions for review and comment. As
justified by water characteristics and as recommended by the WER guidance, we strongly
encourage the application of the WER across a watershed or waterbody as opposed to
application on a discharger by discharger basis, as technically sound and an efficient use of
resources.
In order to meet current needs, but allow for changes suggested by protocol users,
EPA will issue the guidance as "interim." EPA will accept WERs developed using this
guidance, as well as by using other scientifically defensible protocols. OW expects the
interim WER guidance will be issued in the next two months.
Total Maximum Daily Loads fTMDLsl and National Pollutant Discharge Elimination System
(NPDES> Permits
o Dynamic Water Quality Modeling
Although not specifically part of the reassessment of water quality criteria for metals,
dynamic or probabilistic models are another useful tool for implementing water quality
criteria, especially for those criteria protecting aquatic life. These models provide another
way to incorporate site-specific data. The 1991 Technical Support Document for Water
Quality-based Toxics Control (TSD) (EPA/505/2-90-001) describes dynamic, as well as static
(steady-state) models. Dynamic models make the best use of the specified magnitude,
duration, and frequency of water quality criteria and, therefore, provide a more accurate
representation of the probability that a water quality standard exceedence will occur. In
contrast, steady-state models make a number of simplifying, worst case assumptions which
makes them less complex and less accurate than dynamic models.
Dynamic models have received increased attention over the last few years as a result
of the widespread belief that steady-state modeling is over-conservative due to
environmentally conservative dilution assumptions. This belief has led to the misconception
that dynamic models will always lead to less stringent regulatory controls (e.g., NPDES
effluent limits) than steady-state models, which is not true in every application of dynamic
models. EPA considers dynamic models to be a more accurate approach to implementing
water quality criteria and continues'to recommend their use. - Dynamic modeling does require
commitment of resources to develop appropriate data. (See Attachment #3 and the TSD for
details on the use of dynamic models.)
o Dissolved-Total Metal Translators
Expressing water quality criteria as the dissolved form of a metal poses a need
able to translate from dissolved metal to total recoverable metal for TMDLs and NPD
permits. TMDLs for metals must be able to calculate: (1) dissolved metal in order to
ascertain attainment of water quality standards, and (2) total recoverable metal in order to
achieve mass balance necessary for permitting purposes.
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EPA's NPDES regulations require that limits of metals in permits be stated as total
recoverable in most cases (see 40 CFR §122.45(c)) except when an effluent guideline
specifies the limitation in another form of the metal, the approved analytical methods
measure only dissolved metal, or the permit writer expresses a metals limit in another form
(e.g., dissolved, valent, or total) when required to carry out provisions of the Clean Water
Act. This is because the chemical conditions in ambient waters frequently differ substantially
from those in the effluent, and there is no assurance that effluent paniculate metal would not
dissolve after discharge. The NPDES rule does not require that State water quality standards
be expressed as total recoverable; rather, the rule requires permit writers to translate between
different metal forms in the calculation of the permit limit so that a total recoverable limit
can be established. Both the TMDL and NPDES uses of water quality criteria require the
ability to translate between dissolved metal and total recoverable metal. Attachment #3
provides methods for this translation.
Guidance on Monitoring
o Use of Clean Sampling and Analytical Techniques
In assessing waterbodies to determine the potential for toxicity problems due to
metals, the quality of the data used is an important issue. Metals data are used to determine
attainment status for water quality standards, discern trends in water quality, estimate
background loads for TMDLs, calibrate fate and transport models, estimate effluent
concentrations (including effluent variability), assess permit compliance, and conduct
research. The quality of trace level metal data, especially below 1 ppb, may be
compromised due to contamination of samples during collection, preparation, storage, and
analysis. Depending on the level of metal present, the use of "clean" and "ultraclean"
techniquesTor sampling and analysis may be critical to accurate data for implementation of
aquatic life criteria for metals.
The magnitude of the contamination problem increases as the ambient and effluent
metal concentration decreases and, therefore, problems are more likely in ambient
measurements. "Clean" techniques refer to those requirements (or practices for sample
collection and handling) necessary to produce reliable analytical data in the part per billion
(ppb) range. "Ultraclean" techniques refer to those requirements or practices necessary to
produce reliable analytical data in the part per trillion (ppt) range. Because typical
concentrations of metals in surface waters and effluents vary from one metal to another, the
effect of contamination on the quality of metals monitoring data varies appreciably.
We plan to develop protocols on the use of clean and ultra-clean techniques and are
coordinating with the United States Geological Survey (USGS) on this project, because USGS
has been doing work on these techniques for some time, especially the sampling procedures.
We anticipate that our draft protocols for clean techniques will be available in late calendar
year 1993. The development of comparable protocols for ultra-clean techniques is underway
and will be available in 1995. In developing these protocols, we will consider the costs of
these techniques and will give guidance as to the situations where their use is necessary.
Appendix B to the WER guidance document provides some general guidance on the use of
7
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clean analytical techniques. (See Attachment #4.) We recommend that this guidance be used
by States and Regions as an interim step, while the clean and ultra-clean protocols are being
developed.
o Use of Historical Data
The concerns about metals sampling and analysis discussed above raise corresponding
concerns about the validity of historical data. Data on effluent and ambient metal
concentrations are collected by a variety of organizations including Federal agencies (e.g.,
EPA. USGS), State pollution control agencies and health departments, local government
agencies, municipalities, industrial dischargers, researchers, and others. The data are
collected for a variety of purposes as discussed above.
Concern about the reliability of the sample collection and analysis procedures is
greatest where they have been used to monitor very low level metal concentrations.
Specifically, studies have shown data sets with contamination problems during sample
collection and laboratory analysis, that have resulted in inaccurate measurements. For
example, in developing a TMDL for New York Harbor, some historical ambient data showed
extensive metals problems in the harbor, while other historical ambient data showed only
limited metals problems. Careful resampling and analysis in 1992/1993 showed the latter
view was correct. The key to producing accurate data is appropriate quality assurance (QA,
and quality control (QQ procedures. We believe that most historical data for metals,
collected and analyzed with appropriate QA and QC at levels of 1 ppb or higher, are
reliable. The data used in development of EPA criteria are also considered reliable, both
because they meet the above test and because the toxicity test solutions are created by adding
known amounts of metals.
With_respect to effluent monitoring reported by an NPDES permittee, the permittee is
responsible for collecting and reporting quality data on a Discharge Monitoring Report
(DMR). Permitting authorities should continue to consider the information reported to be
true, accurate, and complete as certified by the permittee. Where the permittee becomes
aware of new information specific to the effluent discharge that questions the quality of
previously submitted DMR data, the permittee must promptly submit that information to the
permitting authority. The permitting authority will consider all information submitted by the
permittee in determining appropriate enforcement responses to monitoring/reporting and
effluent violations. (See Attachment i4 for additional details.)
Summary
The management of metals in the aquatic environment is complex. The science
supporting our technical and regulatory programs is continuing to evolve, here as in all
areas. The policy and guidance outlined above represent the position of OW and should be
incorporated into ongoing program operations. We do not expect that ongoing operations
would be delayed or deferred because of this guidance. i
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If you have questions concerning this guidance, please contact Jim Hanlon, Acting
Director, Office of Science and Technology, at 202-260-5400. If you have questions on
specific details of the guidance, please contact the appropriate OW Branch Chief. The
Branch Chiefs responsible for the various areas of the water quality program are: Bob April
(202-260-6322, water quality criteria), Elizabeth Fellows (202-260-7046, monitoring and data
issues), Russ Kinerson (202-260-1330, modeling and translators), Don Brady (202-260-7074,
Total Maximum Daily Loads), Sheila Frace (202-260-9537, permits), Dave Sabock
(202-260-1315, water quality standards), Bill Telliard (202-260-7134, analytical methods)
and Dave Lyons (202-260-8310, enforcement).
Attachments
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ATTACHMENT #1
TECHNICAL GUIDANCE FOR METALS
Schedule of Upcoming Guidance
Water-effect Ratio Guidance - September 1993
Draft "Clean" Analytical Methods - Spring 1994
Dissolved Criteria - currently being done; as testing is completed, we will release the
updated percent dissolved data
Draft Sediment Criteria for Metals - 1994
Final Sediment Criteria for Metals - 1995
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ATTACHMENT #2
GUIDANCE DOCUMENT
ON DISSOLVED CRITERIA
Expression of Aquatic Life Criteria
October 1993
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10-1-93
Percent Dissolved in Aquatic Toxicity Tests on Metals
The attached table contains all the data that were found
concerning the percent of the total recoverable metal that was
dissolved in aquatic toxicity tests. This table is intended to
contain the available data that are relevant to the conversion of
EPA's aquatic life criteria for metals from a total recoverable
basis to a dissolved basis. (A factor of 1.0 is used to convert
aquatic life criteria for metals that are expressed on the basis
of the acid-soluble measurement to criteria expressed on the
basis of the total recoverable measurement.) Reports by Grunvald
(1992) and Brungs et al. (1992) provided references to many of
the documents in which pertinent data were found. Each document
was obtained and examined to determine whether it contained
useful data.
"Dissolved" is defined as metal that passes through a 0.45-pm
membrane filter. If otherwise acceptable, data that were
obtained using 0.3-pm glass fiber filters and 0.1-^m membrane
filters were used, and are identified in the table; these data
did not seem to be outliers.
Data were used only if the metal was in a dissolved inorganic
form when it was added to the dilution water. In addition, data
were used only if they were generated in water that would have
been acceptable for use as a dilution water in tests used in the
derivation of water quality criteria for aquatic life; in
particular, the pH had to be between 6.5 and 9.0, and the
concentrations of total organic carbon (TOG) and total suspended
solids (TSS) had to be below 5 mg/L. Thus most data generated
using rrver water would not be used.
Some data were not used for other reasons. Data presented by
Carroll et al. (1979) for cadmium were not used because 9 of the
36 values were above 150%. Data presented by Davies et al.
(1976) for lead and Holcombe and Andrew (1978) for zinc were not
used because "dissolved" was defined on the basis of
polarography, rather than filtration.
Beyond this, the data were not reviewed for quality. Horowitz et
al. (1992) reported that a number of aspects of the filtration
procedure might affect the results. In addition, there might be
concern about use of "clean techniques" and adequate QA/QC.
Each line in the table is intended to represent a separate piece
of information. All of the data in the table were determined in
fresh water, because no saltwater data were found. Data are
becoming available for copper in salt water from the New York
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Harbor study; based on the first set of tests, Hansen (1993)
suggested that the average percent of the copper that is
dissolved in' sensitive saltwater tests is in the range of 76 to
82 percent.
A thorough investigation of the percent of total recoverable
metal that is dissolved in toxicity tests might attempt to
determine if the percentage is affected by test technique
(static, renewal, f low- through ), feeding (were the test animals
fed and, if so, what food and how much) , water quality
characteristics (hardness, alkalinity, pH, ' salinity) , test
organisms (species, loading) , etc.
The attached table also gives the freshwater criteria
concentrations (CMC and CCC) because percentages for total
recoverable concentrations much (e.g., more than a factor of 3)
above or below the CMC and CCC are likely to be less relevant.
When a criterion is expressed as a hardness equation, the range
given extends from a hardness of 50 mg/L to a hardness of 200
rog/L.
The following is a summary of the available information for each
metal:
The data available indicate that the percent dissolved is about
100, but all the available data are for concentrations that are
much higher than the CMC and CCC.
CadmjuTO
— j, . ' /
Schuytema et al. (1984) reported that "there were no real
differences" between measurements of total and dissolved cadmium
at concentrations of 10 to 80 ug/L (pH - 6.7 to 7.8, hardness »
25 mg/L, and alkalinity « 33 mg/L); total and dissolved
concentrations were said to be "virtually equivalent1*.
The CMC and .CCC are close together and only range from 0.66 to
8.6 ug/L. The only available data that are known to be in the
range of the CMC and CCC were determined with a glass fiber
filter. The percentages that are probably most relevant are 75,
92, 89, 78, and 80.
Chromium f III 1
The percent dissolved decreased as the total recoverable
concentration increased, even though the highest concentrations
reduced the pH substantially. The percentages that are probab;
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roost relevant to the CMC are 50-75, wherean the percentages that
are probably most relevant to the CCC are 86 and 61.
Chromium(VI)
The data available indicate that the percent dissolved is about
100, but all the available data are for concentrations that are
much higher than the CMC and CCC.
Copper
Howarth and Sprague (1978) reported that the total and dissolved
concentrations of copper were "little different" except when the
total copper concentration was above 500 ug/L at hardness « 360
ng/L and pH = 8 or 9. Chakoumakos et al. (1979) found that the
percent dissolved depended more on alkalinity than on hardness,
pH, or the total recoverable concentration of copper.
/
Chapman (1993) and Lazorchak (19S7) both found that the addition
of daphnid food affected the percent dissolved very little, even
though Chapman used yeast-trout chow-alfalfa whereas Lazorchak
used algae in most tests, but yeast-trout chow-alfalfa in some
tests. Chapman (1993) found a low percent dissolved with and
without food, whereas Lazorchak (1987) found a high percent
dissolved with and without food. All of Lazorchak's values were
in high hardness water; Chapman's one value in high hardness
water was much higher than his other values.
Chapman (1993) and Lazorchak (1987) both compared the effect of
food on the total recoverable LC50 with the effect of food on the
dissolved LC50. Both authors found that food raised both the
dissolved LC50 and the total recoverable LC50 in about the ,same
proportion, indicating that food did not raise the total
recoverable LC50 by sorbing metal onto food particles; possibly .
the food raised both LCSOs by (a) decreasing the toxicity of
dissolved metal, (b) forming nontoxic dissolved complexes with
the metal, or (c) reducing uptake.
The CMC and CCC are close together and only range from 6.5 to 34
ug/L. The percentages that are probably most relevant are 74,
95, 95, 73, 57, 53, 52, 64, and 91.
Lead
The data presented in Spehar et al. (1978) were from Holcombe et
al. (1976). Both Chapman (1993) and Holcombe et al. (1976) found
that the percent dissolved increased as the total recoverable
concentration increased. It would seem reasonable to expect more
precipitate at higher total recoverable concentrations and
-------
therefore a lower percent dissolved at higher concentrations.
The increase in percent dissolved with increasing concentration
might be due to a lowering of the pH as more metal is added if
the stock solution was acidic.
The percentages that are probably most relevant to the CMC are 9,
18, 25, 10, 62, 68, 71, 75, 81, and 95, whereas the percentages
that are probably most relevant to the CCC are 9 and 10.
Mercury
The only percentage that is available is 73, but it is for a
concentration that is much higher than the CMC.
Nickel
The percentages that are probably most relevant to the CMC are
88, 93, 92, and 100, whereas the only percentage that is probably
relevant to the CCC is 76.
Selenium
No data are available.
Silver
There is a CMC, but not a CCC. The percentage dissolved seems to
be greatly reduced by the food used to feed daphnids, but not by
the food used to feed fathead minnows. The percentages that are
probably~most relevant to the CMC are 41, 79, 79, 73, 91, 90, and
93.
Zinc
The CMC and CCC are close together and only range from 59 to 210
ug/L. The percentages that are probably most relevant are 31,
77, 77, 99, 94, 100, 103, and 96.
-------
Recommended Values (*)A and Ranges of Measured Percent: Dissolved
' Considered Most Relevant in Fresh Water
Metal £M£ CC£
Recommended Recommended
Value f%l (Ranoc %1 Value f%l fRanae
Arsenic (III)
Cadmium
Chromium (II I)
Chromium (VI )
Copper
Lead
Mercury
Nickel
Selenium
Silver
Zinc
95
85
85
95
85
50
85
85
NAE
85
85
100-104*
75-92
50-75
100*
52-95
9-95
73*
88-100
NAC
41-93
31-103
95
85
85
95
85
25
NAE
85
NAE
YY°
85
100-1048
75-92
61-86
100B
52-95
9-10
NAE
76
NAC
YYD
31-103
A The recommended values are based on current knowledge and are
subject to change as more data becomes available.
8 All available data are for concentrations that are much higher
than the CMC.
^
c NA - No data are available.
0 YY » A CCC is not available, and therefore cannot be adjusted.
E NA - BioaccumuLative chemical and not appropriate to adjust to
percent dissolved.
-------
Concn.A
fua/Ll
Percent
Diss.1 nc
Soecies0
ARSENlCfllll { Freshwater: CCC «
600-15000
12600
CADMIUM
0.16
0.28
0.4-4.0
13
15-21
42
10
35
51
6-80
3-232
450-6400
104 5
100 3
(Freshwater:
41 ?
75 ?
92° ?
89 3
96 8
84 4
78 ?
77 ?
59 ?
80 8
90H 5
70 5
?
FM
CCC - 0.66
DM
DM
CS
FM
FM
FM
DM
DM
DM
?
?
FM
SRFB Food Hard. Alk. Efl
190 ug/L; CMC = 360 ug/L)
?
F
to 2.0
R
R
F
F
S
S
S
S
S
S
F
F
7
No
ug/L;
Yes
Yes
No
No
No
No
No
No
No
No
?
No
48
44
CMC «
53
103
21
44
42
45
51
105
209
47
46
202
41
43
1.8
46
83
19
43
31
41
38
88
167
44
42
157
7.6
7.4
to 8.6
7.6
7.9
7.1
7.4
7.5
7.4
7.5
8.0
8.4
7.5
7.4
7.7
Ref.
Lima et al. 1984
Spehar and Fiandt 1986
ug/L)'
Chapman 1993
Chapman 1993
Finlayson and Verrue 1982
Spehar and Fiandt 1986
Spehar and Carlson 1984
Spehar and Carlson 1984
Chapman 1993
Chapman 1993
Chapman 1993
Call et al. 1982
Spehar et al. 1978
Pickering and Cast 1972
-------
(Freshwater: CCC - 120 to 370 ug/L;; CMC = 980 to 3100 ug/L)'
5-13
19-495
>1100
42
114
16840
26267
27416
58665
CHROMIUM
>25,000
43,300
CQEEEB
10-30
40-200
30-100
100-200
20-200
40-300
94 ?
86 ?
50-75 ?
CA ?
3H *
HI ">
61 i
26 ?
32 ?
27 ?
23 ?
(VI) (Freshwater
100 1
99.5 4
(Freshwater: CCC
74 ?
78 ?
79 ?
82 ?
86 ?
87 ?
SG
SG
SG
DM
DM
fc/1 1
DM
DM
DM
DM
: ccc •
FM.GF
FM
• 6.5
CT
CT
CT
CT
CT
CT
F
It
F
R
R
S
S
S
S
=• 11
F
F
?
?
NO
Yes
Yes
No
No
No
No
ug/L; CMC
Yes
No
25
25
25
206
52
<51
110
96
190
«= 16
220
44
to 21 ug/L; CMC = 9
F
F
F
F
F
F
No
No
NO
No
No
NO
27
154
74
192
31
83
24
24
24
166
45
9
9
10
25
ug/L)
214
43
.2 to
20
20
23
72
78
70
7.3
7.2
7.0
8.2
7.4
6.3'
6.7
6.01
6.2'
7.6
7.4
Stevens and Chapman
Stevens and Chapman
Stevens and Chapman
Chapman 1993
Chapman 1993
Chapman 1993
Chapman 1993
Chapman 1993
Chapman 1993
1984
1984
1984
Adelman and Smith 1976
Spehar and Fiandt 1986
34 ug/L)p
7.0
6.8
7-6
7.0
8.3
7.4
Chakoumakos et al.
Chakoumakos et al.
Chakoumakos et al.
Chakoumakos et al.
Chakoumakos et al.
Chakoumakos et al.
1979
1979
1979
1979
1979
1979
10-80
89
CT
NO
25
169 8.5 Chakoumakos et al. 1979
-------
300-1300
100-400
1-4'
L2-911
L8-19
201
50
1751
5-52
*r ^f **
6-80
6.7
35
13
^k V
16
A v
51
32
W •»
33
•* •*
39
25-84
17
120
15-90
12-162
28-58
26-59
56,101
92 ?
94 ?
125-167 2
79-84 3
95 2
95 1
96 2
91 2
>82K ?
83° ?
57 ?
43 ?
73 ?
57 ?
39 ?
53 ?
52 ?
64 ?
96 14
91 6
88 14
74 19
80M ?
85 6
79 7
86 2
CT
CT
CD
CD
DA
DA
FM
FM
FM
CS
DM
DM
DM
DM
DM
DM
DM
DM
FM,GM
DM
SG
?
BG
DM
DM
DM
F
F
R
|R
s
R
S
R
F
F
S
S
R
R
R
S
S
S
S
S
S
S
F
R
R
R
No
No
Yes
Yes
No
No
No
No
YesL
No
No
Yes
Yes
Yes
Yes
No
No
No
No
NO
NO
No
YesL
No
YesM
AA
YesM
195
70
31
31
52
31
52
31
47
21
49
48
211
51
104
52
105
106
50
52
48
48
45
168
168
168
160
174
38
38
55
38
55
38
43
19
37
39
169
44
83
45
79
82
40
43
47
47
43
117
117
117
7.0
8.5
7.2
7.2
7.7
7.2
7.7
7.2
8.0
7.1
7.7
7.4
8.1
7.6
7.8
7.8
7.9
8.1
7.0
7.3
7.3
7.7
7-8
8.0
8.0
8.0
Chakoumakos et al. 1979
Chakoumakos et al. 1979
Carlson et al. 1986a,b
Carlson et al. I986a,b
Carlson et al. 1986b
Carlson et al. I986b :
Carlson et al. 1986b .
Carlson et al. 1986b
Lind et al. 1978
Finlayson and Verrue 1982
Chapman 1993
Chapman 1993
Chapman 1993
Chapman 1993
Chapman 1993
Chapman 1993
Chapman 1993
Chapman 1993
Hanmermeister et al. 1983
Hammermelster et al. 1983
Hamroermelater et al. 1983
Call et al. 1982
Benoit 1975
Lazorchak 1987
Lazorchak 1987
Lazorchak 1987
-------
96
160
230-3000
86
94
>69->79
4
1
?
FM
FM
CR
F
S
F
No
No
No
44
203
17
43
171
13
7.4
8.2
** • «b
7.6
17
181
193
612
952
1907
7-29
34
58
119
235
474
4100
2100
(Freshwater: CCC « 1.3
9 ? DM
18 ? DM
25 ? DM
29 ? DM
33 ? DM
-38 ? DM
10 ? E2
62" ? BT
68" 7 BT
71M ? BT
75M ? BT
81H ? BT
82M ? BT
220-2700
580
79
96
95
7 FM
14 FM,GM,DM
14 SG
R
R
R
S
S
S
F
F
F
F
F
F
S
S
No
No
,; CMC
Yes
Yes
Yes
No
No
No
No
Yes
Yes
Yes
Yes
Yes
No
No
No
No
203
17
- 34
52
102
151
50
100
150
22
44
44
44
44
44
44
44
49
51
171
13
to 200
47
86
126
••
-------
NICKEL (Freshwater: CCC •> 88 to 280 ug/L; CMC «= 790 to 2500 ug/L)F
21
150
578
645
1809
1940
2344
81 ?
76 ?
87 ?
88 ?
93 ?
92 ?
100 ?
DM
DM
DM
DM
DM
DM
DM
R
R
p
s
s
s
s
Yes
Yes
Yes
No
No
No
No
51
107
205
54
51
104
100
49
87
161
43
44
84
84
7.4
7.8
8.1
7.7
7.7
8.2
7.9
4000
90
PK
NO
21
Chapman 1993
Chapman 1993
Chapman 1993
Chapman 1993
chapman 1993
Chapman 1993
Chapman 1993
JRB Associates 1983
SELENIUM (FRESHWATER: CCC - 5 ug/L; CMC « 20 ug/L)
No data are available.
0.19
9.98
4.0
4.0
3
2-54
2-32
4-32
5-89
6-401
^
74 1
13 1
41 1
11 i
79 1
79 1
73 1
91 1
90 1
93 1
\
r DM
p DM
? DM
r DM
? FM
r FM
P FM
P FM
> FM
r FM
s
s
s
s
s
s
s
s
s
s
_,
No
Yes
No
Yes
No
Yes0
No
No
No
No
47
47
36
36
51
49
50
48
120
249
37
37
25
25
49
49
49
49
49
49
7.6
7.5
7.0
7.0
8.1
7.9
8.1
8.1
8.2
8.1
»»«i
Chapman 1993
Chapman 1993
Nebeker et al.
Nebeker et al.
UWS 1993
UWS 1993
UWS 1993
UWS 1993
UWS 1993
UWS 1993
1983
1983
1Q
-------
(Freshwater: CCC - 59 to 190 ug/L; CMC 65 to 210 ug/L)f
52
62
191
356
551
741
7'
1B-2731
1671
180
188-3931
551
40-500
1940
5520
<4000
>4000
160-400
240
31
77
77
74
78
76
71-129
81-107
99
94
100
100
95°
100
83
90
70
103
96
?
?
?
?
?
?
2
2
2
1
2
1
?
?
7
?
?
13
13
DM
DM
DM
DM
DM
DM
CD
CD
CD
CD
FM
FM
CS
AS
AS
FM
FM
FM,GM,DM
SG
R
R
P
0
S
s
S
R
R
R
S
R
S
F
F
F
F
F
S
S
Yes
Yes
Yes
No
No
No
Yes
Yes
No
No
No
No
No
No
No
No
No
No
No
211
104
52
54
105
196
31
31
31
52
31
52
21
20
20
204
204
52
49
169
83
47
47
85
153
38
38
38
55
38
55
19
12
12
162
162
43
46
8.2
7.8
7.5
7.6
8.1
8.2
7.2
7.2
7.2
7.7
7.2
7.7
7.1
7.1
7.9
7.7
7.7
7.5
7.2
Chapman 1993
Chapman 1993
Chapman 1993
Chapman 1993
Chapman 1993
Chapman 1993
Carlson et al. 1986b
Carlson et al. 1986b
Carlson et al. I986b
Carlson et al. 1986b
Carlson et al. 1986b
Carlson et al. 1986b
Finlayson and Verrue 1982
Sprague 1964
Sprague 1964
Mount 1966
Mount 1966
Hammermeister et al. 1983
Hammermeister et al. 1983
A Total recoverable concentration.
• Except as noted, a 0.45-fim membrane filter was used.
11
-------
c Number of paired comparisons,
0 The abbreviations used are:
AS
BT
CD
CR
CS
CT
Atlantic salmon DM » Daphnia magna
Brook trout EZ » Elassoma zonatum
Ceriodaphnia dubia I FH » Fathead minnow
Crayfish GF » Goldfish
Chinook salmon GN - Gammarid
Cutthroat trout PK « Palaemonetes kadiakenaia
DA - Daphnids SG - Salmo gairdnerj,
e The abbreviations used are:
S - static
R - renewal
F - flow-through
* The two numbers are for hardnesses of 50 and 200 mg/L, respectively.
0 A 0.3-pm glass fiber filter was used.
H A 0.10-pm membrane filter was used.
1 The pH was below 6.5.
' The dilution water was a clean river water with TSS and Toe below 5 mg/L.
K Only limited information is available concerning this value.
L It is assumed that the solution that was filtered was from the test chambers that
contained fish and food.
M The food was algae.
H The food was yeast-trout chow-alfalfa.
0 The food was frozen adult brine shrimp.
-------
References' •
Adelman, I.R.., and L.L. Smith, Jr. 19*76. Standard Test Fish
Development. Part I. Fathead Minnows fPimephales promelas) and
Goldfish rcarassius auratusl as Standard Fish in Bioassays and
Their Reaction to Potential Reference Toxicants. EPA-600/3-76-
06la. National Technical Information Service, Springfield, VA.
Page 24.
Benoit, D.A. 1975. Chronic Effects of Copper on Survival,
Growth, and Reproduction of the Bluegill (Lepomis joacrochirus).
Trans. Am. Fish. Soc. 104:353-358.
Brungs, W.A., T.S. Holderman, and M.T. Southerland. 1992.
Synopsis of Water-Effect Ratics for Heavy Metals as Derived for
Site-Specific Water Quality Criteria.
Call, D.J., L.T. Brooke, and D.D. Vaishnav. 1982. Aquatic
Pollutant Hazard Assessments and Development of a Hazard
Prediction Technology by Quantitative Structure-Activity
Relationships. Fourth Quarterly Report. University of
Wisconsin-Superior, Superior, WI.
Carlson, A.R., H. Nelson, and D. Haamermeir-ter. 19S6a*
Development and Validation of Site-Specific Water Quality
Criteria for Copper. Environ. Toxicol. Chem. 5:997-1012.
Carlson, A.R., H. Nelson, and C. Hammermeister. 1986b.
Evaluation of Site-Specific Criteria for Copper and Zinc: An
Integration of Metal Addition Toxicity, Effluent and Receiving
Water Toxicity, and Ecological Survey Data. EPA/600/S3-86-026.
National- Technical Information Service, Springfield, VA.
Carroll, J.J., S.J. Ellis, and W.s. Oliver. ,1979. Influences of
Hardness Constituents on the Acute Toxicity of Cadmium to Brook
Trout (Salvelinus /ontinalis).
Chakoumakos, C., R.C. Russo, and R.V. Thurston. 1979. Toxicity
of Copper to Cutthroat Trout (Salao clarJci) under Different
Conditions of Alkalinity, pH, and Hardness. Environ. Sci.
Technol. 13:213-219.
Chapman, G.A. 1993. Memorandum to C. Stephan. June 4.
Davies, P.H., J.P. Goettl, Jr., J.R. Sinley, and N.F. Smith.
1976. Acute and Chronic Toxicity of Lead to Rainbow Trout Salmo
gairdnari, in Hard and Soft Water. Water Res. 10:199-206.
Finlayson, B.J., and K.M Verrue. 1982. Toxicities of Copper,
Zinc, and Cadmium Mixtures to Juvenile Chinook Salmon. Trans.
Am. Fish. Soc. 111:645-650.
13
-------
Geckler, J.R., W.B. Horning, T.M. Neiheisel, Q.H. Pickering, E.L.-
Robinson, and C.E. Stephan. 1976. Validity of Laboratory Tests
for Predicting Copper Toxicity in Streams. EPA-600/3-76-116.
National Technical Information Service, Springfield, VA. Page
118;
Grunwald, 0. 1992. Metal Toxicity Evaluation: Review, Results,
and Data Base Documentation.
Hamnermeister, D., C. Northcott, L. Brooke,, and D. Call. 1983.
Comparison of Copper, Lead and Zinc Toxicity to Four Animal
Species in Laboratory and ST. Louis River Water. University of
Wisconsin-Superior, Superior, WI.
Hansen, D.J. 1993. Memorandum to C.E. Stephan. April 15.
Holcombe, G.W., D.A. Benoit, E.K. Leonard, and J.M. McKim. 1976.
Long-Term Effects of Lead Exposure on Three Generations of Brook
Trout (Salvelinus fontinalis). J. Fish. Res. Bd. Canada 33:1731-
1741.
Holcombe, G.W., and R.W. Andrew. 1978. The Acute Toxicity of
Zinc to Rainbow and Brook Trout. EPA-600/3-78-094. National
Technical Information Service, Springfield, VA.
Horowitz, A.J., K.A. Elrick, and M.R. Colberg. 1992. The EffecJ
of Membrane Filtration Artifacts on Dissolved Trace Element
Concentrations. Water Res. 26:753-763.
Howarth, R.S., and J.B. Sprague. 1978. Copper Lethality to
Rainbow Trout in Waters on Various Hardness and pH. Hater Res.
12:455-462.
JRB Associates. 1983. Demonstration of the Site-specific
Criteria Modification Process: Selser's Creek, Ponchatoula,
Louisiana;
Lazorchak, J.M. 1987. The Significance of Weight Loss of
Daphni,a maana Straus During Acute Toxicity Tests with Copper.
Ph.D. Thesis.
Lima, A.R., C. Curtis, D.E. Hammermeistcr, T.P. Mark.ee, C.E.
Northcott, L.T. Brooke. 1984. Acute and Chronic Toxicities of
Arsenic(III) to Fathead Minnows, Flagfish, Daphnids, and an
Amphipod. Arch. Environ. Contam. Toxicbl. 13:595-601.
Lind, D., K. Alto, and S. Chatterton. 1978. Regional Copper-
Nickel Study. Draft.
Mount, D.I. 1966. The Effect of Total Hardness and pR on Acute
Toxicity of Zinc to Fish. Air Water Pollut. Int. J. 10:49-56.
14
-------
ttebeker, A...V., C.K. McAuliffe, R. Mshar, and D.G. Stevens. 1983.
Toxicity of Silver to Steelhead and Kainbow Trout, Fathead
Minnows, and Daphnia magna. Environ. Toxicol. Chem. 2:95-104.
Pickering, Q.P., and M.H. Cast. 1972. Acute and Chronic
Toxicity of Cadmium to the Fathead Minnow (Pimephales pronelas).
J. Fish. Res. Bd. Canada 29:1099-1106.
Rice, D.W., Jr., and F.L. Harrison. 1983. The Sensitivity of
Adult, Embryonic, and Larval Crayfish Procaabarus clarJcii to
Copper. NUREG/CR-3133 or UCRL-53048. National Technical
Information Service, Springfield, VA.
Schuytema, G.S., P.O. Nelson, K.W. Malueg, A.V. Nebeker, D.F.
Krawczyk, A.K. Ratcliff, and J.H. Gakstatter. 1984. Toxicity of
Cadmium in Water and Sediment Slurries to Daphnia magna.
Environ. Toxicol. Chem. 3:293-308.
Spehar, R.L., R.L. Anderson, and J.T. Fiandt. 1978. Toxicity
and Bioaccumulation of Cadmium and Lead in Aquatic Invertebrates.
Environ. Pollut. 15:195-208. .
Spehar, R.L., and A.R. Carlson. 1984. Derivation of Site-
Specific Water Quality Criteria for Cadmium and the St. Louis
River Basin, Duluth,.Minnesota. Environ. Toxicol. Chem. 3:651-
665.
Spehar, R.L., and J.T. Fiandt. 1986. Acute and Chronic Effects
of Water Quality Criteria-Based Metal Mixtures on Three Aquatic
Species. Environ. Toxicol. Chem. 5:917-931.
Sprague, J.B. 1964. Lethal Concentration of Copper and Zinc for
Young Atlantic Salmon. J. Fish. Res. Bd. Canada 21:17-9926.
Stevens, D.G., and G.A. Chapman. 1984. Toxicity of Trivalent
Chromium to Early Life Stages of Steelhead Trout. Environ.
Toxicol. Chem. 3:125-133.
University of Wisconsin-Superior. 1993. Preliminary data from
work assignment 1-10 for Contract No. 68-C1-0034.
15
-------
ATTACHMENT
GUIDANCE DOCUMENT
ON DYNAMIC MODELING AND TRANSLATORS
August 1993
Total Maximum Daily Loads (TMDLs) and Permits
o Dynamic Water Quality Modeling
Although not specifically pan of the reassessment of water quality criteria for metals,
dynamic or probabilistic models are another useful tool for implementing water quality
criteria, especially those for protecting aquatic life. Dynamic models make best use of the
specified magnitude, duration, and frequency of water quality criteria and thereby provide a
more accurate calculation of discharge impacts on ambient water quality. In contrast, steady-
state modeling is based on various simplifying assumptions which makes it less complex and
less accurate than dynamic modeling. Building on accepted practices in water resource
engineering, ten years ago OW devised methods allowing the use of probability distributions
in place of worst-case conditions. The description of these .models and their advantages and
disadvantages is found in the 1991 Technical Support Document for Water Quality-based
Toxic Control (TSD).
Dynamic models have received increased attention in the last few years as a result of
the perception that static modeling is over-conservative due to environmentally conservative
dilution assumptions. This has led to the misconception that dynamic models will always
justify less stringent regulatory controls (e.g. NPDES effluent limits) than static models. In
effluent dominated waters where the upstream concentrations are relatively constant,
however, a dynamic model will calculate a more stringent wasteload allocation than will a
steady state model. The reason is that the critical low flow required by many State water
quality standards in effluent dominated streams occurs more frequently than once every three
years. When other environmental factors (e.g. upstream pollutant concentrations) do not
vary appreciably, then the overall return frequency of the steady state model may be greater
than once in three years. A dynamic modeling approach, on the other hand, would be more
stringent, allowing only a once in three year return frequency. As a result, EPA considers
dynamic models to be a more accurate rather than a less stringent approach to implementing
water quality criteria.
The 1991 TSD provides recommendations on the use of steady state and dynamic
water quality models. The reliability of any modeling technique greatly depends on tile
accuracy of the data used in the analysis. Therefore, the selection of a model also depends
upon the data. EPA recommends that steady state wasteload allocation analyses generally be
used where few or no whole effluent toxicity or specific chemical measurements are
available, or where daily receiving water flow records are not available. Also, if staff
resources are insufficient to use and defend the use of dynamic models, then steady state
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models may be necessary. If adequate receiving water flow and effluent concentration data
are available to estimate frequency distributions, EPA recommends that one of the dynamic
wasteload allocation modeling techniques be used to derive wasteload allocations which will
more exactly maintain water quality standards. The minimum data required for input into
dynamic models include at least 30 years of river flow data and one year of effluent and
ambient pollutant concentrations.
o Dissolved-Total Metal Translators
When water quality criteria are expressed as the dissolved form of a metal, there is a
need to translate TMDLs and NPDES permits to and from the dissolved form of a metal to
the total recoverable form. TMDLs for toxic metals must be able to calculate 1) the
dissolved metal concentration in order to ascertain attainment of water quality standards and
2) the total recoverable metal concentration in order to achieve mass balance. In meeting
these requirements, TMDLs consider metals to be conservative pollutants and quantified as
total recoverable to pres^nre conservation of mass. The TMDL calculates the dissolved or
ionic species of the met based on factors such as total suspended solids (TSS) and ambient
pH. (These assumptions ignore the complicating factors of metals interactions with other
metals.) In addition, this approach assumes that ambient factors influencing metal
partitioning remain constant with distance down the river. This assumption probably is
under the low flow conditions typically used as design flows for permitting of metals (e.g.,
7Q10, 4B3, etc) because erosion, resuspension, and wet weather loadings are unlikely to be
significant and river chemistry is generally stable. In steady-state dilution modeling, metals
releases may be assumed to remain fairly constant (concentrations exhibit low variability)
with time.
EPA-s NPDES regulations require that metals limits in permits be stated as total
recoverable in most cases (see 40 CFR §122.4S(c)). Exceptions occur when an effluent
guideline specifies the limitation in another form of the metal or the approved analytical
methods measure only the dissolved form. Also, the permit writer may express a metals
limit in another form (e.g., dissolved, valent, or total) when required, in highly unusual
cases, to carry out the provisions of the CWA.
The preamble to the September 1984 National Pollutant Discharge Elimination System
Permit Regulations states that the total recoverable method measures dissolved metals plus
that portion of solid metals that can easily dissolve under ambient conditions (see 49 EsdfflQl
Register 38028, September 26,1984). This method is intended to measure metals in the
effluent that are or may easily become environmentally active, while not measuring metals
that are expected to settle out and remain inert
The preamble cites, as an example, effluent from an electroplating facility that adds
lime and uses clarifiers. This effluent will be a combination of solids not removed by t^fc
clarifiers and residual dissolved metals. When the effluent from the clarifien, usually wWa
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high pH level, mixes with receiving water having significantly lower pH level, these solids
instantly dissolve. Measuring dissolved metals in the effluent, in this case, would
underestimate the impact on the receiving water. Measuring with the total metals method, on
the other hand, would measure metals that would be expected to disperse or settle out and
remain inert or be covered over. Thus, measuring total recoverable metals in the effluent
best approximates the amount of metal likely to produce water quality impacts.
However, the NPDES rule does not require in any way that State water quality
standards be in the total recoverable form; rather, the rule requires permit writers to consider
the translation between differing metal forms in the calculation of the permit limit so that a
total recoverable limit can be established. Therefore, both the TMDL and NPDES uses of
water quality criteria require the ability to translate from the dissolved form and the total
recoverable form.
Many toxic substances, including metals, have a tendency to leave the dissolved phase
and attach to suspended solids. The partitioning of toxics between solid and dissolved phases
can be determined as a function of a pollutant-specific partition coefficient and the
concentration of solids. This function is expressed by a linear partitioning equation:
where,
dissolved phase metal concentration,
total metal concentration,
TSS «= total suspended solids concentration, and
partition coefficient.
A key assumption of the linear partitioning equation is that the sorption reaction
reaches dynamic equilibrium at the point of application of the criteria; that is, after allowing
for initial mixing the partitioning of the pollutant between the adsorbed and dissolved forms
can be used at any location to predict the fraction of pollutant in each respective phase.
Successful application of the linear'partitioning equation relies on the selection of the
partition coefficient. The use of a partition coefficient to represent the degree to which
toxics adsorb to solids is most readily applied to organic pollutants; .partition coefficients for
metals are more difficult to define. Metals typically exhibit more complex speciation and
complexation reactions than organics and the degree of partitioning can vary greatly
depending upon site-specific water chemistry. Estimated partition coefficients can be
determined for a number of metals, but waterbody or site-specific observations of dissolved
and adsorbed concentrations are preferred.
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EPA suggests three approaches for instances where a water quality criterion for a
metal is expressed in the dissolved form in a State's water quality standards:
1. Using clean analytical techniques and field sampling procedures with appropriate
QA/QC, collect receiving water samples and determine site specific values of K* for
each metal. Use these K« values to "translate" between total recoverable and
dissolved metals in receiving water. This approach is. more difficult to apply because
it relies upon the availability of good quality measurements of ambient metal
concentrations. This approach provides an accurate assessment of the dissolved metal
fraction providing sufficient samples are collected. EPA's initial recommendation is
that at least four pairs of total recoverable and dissolved ambient metal measurements
be made during low flow conditions or 20 pairs over all flow conditions. EPA
suggests that the average of data collected during low flow or the 95th percentile
highest dissolved fraction for all flows be used. The low flow average provides a
representative picture of conditions during the rare low flow events. The 95th
percentile highest dissolved fraction for all flows provides a critical condition
approach analogous to the approach used to identify low flows and other critical
environmental conditions.
2. Calculate the total recoverable concentration for the purpose of setting the permit
limit. Use a value of 1 unless the permittee has collected data (see til above) to show
that a different ratio should be used. The value of 1 is conservative and will not err
on the side of violating standards. This approach is very simple to apply because it
places the entire burden of data collection and analysis solely upon permitted
facilities. In terms of technical merit, it has the same characteristics of the previous
approach. However, permitting authorities may be faced with difficulties in
negotiating with facilities on the amount of data necessary to determine the ratio and
the necessary quality control methods to assure that the ambient data are reliable.
3. Use the historical data on total suspended solids (TSS) in receiving waterbodies at
appropriate design flows and K* values presented in the Technical Guidance Manual
for Performing Waste Load Allocations. Book U. Streams and Rivers. EPA-440/4-
84-020 (1984) to •translate" between (total recoverable) permits limits and dissolved
metals in receiving water. This approach is fairly simple to apply. However, these
K« values are-suspect due .to possible quality assurance problems with the data used to
develop the values. EPA's initial analysis of this approach and these values in one
site indicates that these K« values generally over-estimate the dissolved fraction of
metals in ambient waters (see Figures following). Therefore, although this approach
may not provide an accurate estimate of the dissolved fraction, the bias in the estimate
is likely to be a conservative one.
EPA suggests that regulatory authorities use approaches i 1 and S2 where States
express their water quality standards in the dissolved form. In those States where the
standards are in the total recoverable or acid soluble form, EPA recommends that no
/ s*
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approach #1.
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M«Mtir«d vs. -odeled Dissolved Copper Concentrations
3.5 T
3
25
2
15
1
0.5
0
—•— Modeled
--u- Measured
•4-
10
IS
20 25
Sampling Station
30
1-
35
40 45
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v«. Hod*lad Diaaolvtd CadaUtui Concentrations
20 25
Sampling Station
Modeled
Measured
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I
Measured vs. Modeled Dissolved Lead Concentrations
10
15 20 25
Sampling Station
30
35
40
Modeled
—ll Measured
I
45
-------
j
M«a»ur«d v». Mod*lad Diaaolvad Mercury Concentrations
0.12 T
o.i 4
0.08
B, 006
3
0.04
0.02
10 15 20 25
Sampling Station
30
- »- Modeled
- n Measured
35
40
45
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Dis«olv«d Hlckal concentrations
-•- Modeled
-t>— Measured
Sampling Station
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ATTACHMENT #4
GUIDANCE DOCUMENT
ON CLEAN ANALYTICAL TECHNIQUES AND MONITORING
October 1993
Guidance on Monitoring
o Use of Clean Sampling and Analytical Techniques
Appendix B to the WER guidance document (attached) provides some general guidance
on the use of clean techniques. The Office of Water recommends that this guidance be used
by States and Regions as an interim step while the Office of Water prepares more detailed
guidance.
o Use of Historical DMR Data
With respect to effluent or ambient monitoring data reported by an NPDES permittee
on a Discharge Monitoring Report (DMR), the certification requirements place the burden on
the permittee for collecting and reporting quality data. The certification regulatipn at 40
CFR 122.22(d) requires permittees, when submitting information, to state: "I certify under
penalty of law that this document and all attachments were prepared under my direction or
supervision in accordance with a system designed to assure that qualified personnel properly
gather and evaluate the information submitted. Based on my inquiry of the person or persons
who manage the system, or those persons directly responsible for gathering the information,
the information submitted is, to the best of my knowledge and belief, true, accurate, and
complete. I am aware that there are significant penalties for submitting false information,
including the possibility of fine and imprisonment for knowing violations."
Permitting authorities should continue to consider the information reported in DMRs
to be true, accurate, and complete as certified by the permittee. Under 40 CFR 122.41(0(8),
however, as soon as the permittee becomes aware of new information specific to the effluent
discharge that calls into question the accuracy of the DMR data, the permittee must submit
such information to the permitting authority. Examples of such information include a new
rinding that the reagents used in the laboratory analysis are contaminated with trace levels of
metals, or a new study that the sampling equipment imparts trace metal contamination. This
information must be specific to the discharge and based on actual measurements rather than
extrapolations from reports from other facilities. Where a permittee submits information
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In addition to submitting the information described above, the permittee also must
develop procedures to assure the collection and analysis of quality data that are true,
accurate, and complete. For .example, the permittee may submit a revised quality assurance
plan that describes the specific procedures to be undertaken to reduce or eliminate trace
metal contamination.
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M.a»ur.d vs. Micelea Dissolved Zlno Concentrations
25
Sampling Station.
30
35
Modeled
Measured
45
-------
Maaaurad vs. Mo4alad Diaaolvad Araanio Concentrations
25
0.5
A
if ^
\
1 \-
10
20 25
Sampling Stilton
30 35
•••-• Modeled
1' Measured
40
I
45
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10-1-93
Appendix B. Guidance concerning tbe Use of "Clean Techniques" and
QA/QC in the Measurement of Trace Metals
Recent information (ShiHer and Boyle 1987; Hindom et al. 1991)
has raised questions concerning the quality of reported
concentrations of trace metals in both fresh and salt (estuarine
and marine) surface waters. A lack of awareness of true ambient
concentrations of metals in saltwater and freshwater systems can
be both a cause and a result of the problem. The ranges of
dissolved metals that are typical in surface waters of the United
States away from the immediate influence of discharges (Bruland
1983; Shiller and Boyle 1985,1987; Trefry et al. 1986; Windom et
al. 1991) are:
Metal Salt water Fresh water
fuo/Ll fuo/Ll
Cadmium 0.01 to 0.2 0.002 to 0.08
Copper 0.1 to 3. 0.4 to 4.
Lead 0.01 to 1. 0.01 to 0.19
Nickel 0.3 to 5. 1. to 2.
Silver O.OOS to 0.2
Zinc 0.1 to 15. 0.03 to 5.
The U.S. EPA (1983,1991) has published analytical methods for
monitoring metals in waters and wastewaters, but these methods
are inadequate for determination of ambient concentrations of
some metals in some surface waters. Accurate and precise
measurement of these low concentrations requires appropriate
attention to seven areas:
1. Use of_"clean techniques" during collecting, handling,
storing, preparing, and analyzing samples to avoid
contamination.
2. Use of analytical methods that have sufficiently low detection
limits.
3. Avoidance of interference in the quantification (instrumental
analysis) step.
4. Use of blanks to assess contamination.
5; Use of matrix spikes (sample spikes) and certified reference
materials (CBMs) to assess interference and contamination.
6. Use of replicates to assess precision.
7. Use of certified-standards.
In a strict sense, the term "clean techniques" refers to
techniques that reduce contamination and enable the accurate and
precise measurement of trace metals in fresh and salt surface
waters. In a broader sense, the tern also refers to related
issues concerning detection limits, quality control, and quality
assurance. Documenting data quality demonstrates the amount of
confidence that can be placed in the data, whereas increasing the
sensitivity of methods reduce the problem of deciding how to
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interpret results that are reported to be below detection limits
This appendix.is written for those analytical laboratories that
want guidance concerning ways to lower detection limits, increase
precision, and/or increase accuracy. The ways to achieve these
goals are to increase the sensitivity of the analytical methods,
decrease contamination, and decrease interference. Ideally,
validation of a procedure for measuring concentrations of metals
in surface water requires demonstration that agreement can be
obtained using completely different procedures beginning with the
sampling step and continuing through the quantification step
(Bruland et al. 1979), but few laboratories have the resources to
compare two different procedures. Laboratories can, however, (a)
use techniques that others have found useful for improving
detection limits, accuracy, and precision, and (b) document data
quality through use of blanks, spikes, CRMs, replicates, and
standards.
In general, in order to achieve accurate and precise measurement
of a particular concentration, both the detection limit and the
blanks should be less than one-tenth of that concentration.
Therefore, the term "metal-free" can be interpreted to mean that
the total amount of contamination that occurs during sample
collection and processing (e.g., from gloves, sample containers,
labware, sampling apparatus, cleaning solutions, air, reagents,
etc.) is sufficiently low that blanks are less than one-tenth a
the lowest concentration that needs to be measured. '
Atmospheric particulates can be a major source of contamination
(Moody 1982; Adeloju and Bond 1985). The term "class-100" refers
to a specification concerning the amount of particulates in air
(Moody 1982); although the specification says nothing about the
composition of the particulates, generic control of particulates
can greatly reduce trace-metal blanks. Except during collection
of samples and initial cleaning of equipment, all handling of
samples, sample containers, labware, and sampling apparatus
should be performed in a class-100 bench, room, or glove box.
Nothing contained or not contained in this appendix adds to or
subtracts from any regulatory requirements set fprth in other EPA
documents concerning metal analyses. The word "must** is used in
this appendix merely to indicate items that are considered very
important by analytical chemists who have worked to increase
accuracy and precision and lower detection limits in trace-metal
analysis. Some items are considered important because they have
been found to have received inadequate attention in some
laboratories performing trace-metal analyses.
Two topics that are not addressed in this appendix are:
1. The "ultraclean techniques" that are likely to be necessary
when trace analyses of mercury are performed.
2. Safety in analytical laboratories.
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Other documents should be consulted if these topics are of
, concern.
Avoiding contamination bv use of "clean techniques^1
Measurement of trace metals in receiving waters must take into
account the potential for contamination during each step in the
process. Regardless of the specific procedures used for
collection, handling/ storage, preparation (digestion,
filtration, and/or extraction), and quantification (instrumental
analysis), the general principles of contamination control must
be applied. Some specific recommendations are:
a. Non-talc latex or class-100 polyethylene gloves must be worn
during all steps from sample collection to analysis. (Talc
seems to be a particular problem with zinc; gloves made with
talc cannot be decontaminated sufficiently.) Gloves should
only contact surfaces that are metal-free; gloves should be
changed if even suspected of contamination.
b. The acid used to acidify samples for preservation and
digestion and to acidify water for final cleaning of labware,
sampling apparatus, and sample containers must be metal-free.
The quality of the acid used should be better than reagent-
grade. Each lot of acid must be analyzed for the metal(s) of
interest before use.
c. The water used to prepare acidic cleaning solutions and to
rinse labware, sample containers, and sampling apparatus may
be prepared by distillation, deionization, or reverse osmosis,
and must be demonstrated to be metal-free.
d. The work area, including bench tops and hoods, should be
cleaned (e.g., washed and wiped dry with lint-free, class-100
wipes) frequently to remove contamination.
e. All handling of samples in the laboratory, including filtering
and analysis, must be performed in a class-100 clean bench or
a glove box fed by particle-free air or nitrogen; ideally the
clean bench or glove box should be located within a class-100
clean room.
f. Labware, reagents, sampling apparatus, and sample containers
must never be left open to the atmosphere; they should be
stored in a class-100 bench, covered with plastic wrap, stored
in a plastic box, or turned upside down on a clean surface.
Minimizing the time between cleaning and using will help
minimize contamination. '
g. Separata sets of sample containers, labware, and sampling
apparatus should be dedicated for different kinds of samples,
e.g., receiving water samples, affluent samples, etc.
h. To avoid contamination of clean rooms, samples that contain
very high concentrations of metals and do not require use of
"clean techniques" should not be brought into clean rooms.
i. Acid-cleaned plastic, such as high-density polyethylene
(HOPE), low-density polyethylene (LDPE), or a f luoroplastic,
must be the only material that ever contacts a sample, except
possibly during digestion for the total recoverable
-.-7
-------
measurement. (Total recoverable samples can be 'digested in
some plast.ic containers.) Even HOPE and LDPE might not be
acceptable for mercury, however.
All labware, sample containers, and sampling apparatus must be
acid-cleaned before use or reuse.
1. Sample containers, sampling apparatus, tubing, membrane
filters, filter assemblies, and other labvare must be
soaked in acid until metal-free. The amount of cleaning
necessary might depend on the amount of contamination and
the length of time the item will be in contact with
samples. For example, if an acidified sample will be
stored in a sample container for three weeks, ideally the
container should have been soaked in an acidified metal-
free solution for at least three weeks.
2. It might be desirable to perform initial cleaning, for
which reagent-grade acid may be used, before the items are
allowed into a clean room. For most metals, items should
be either (a) soaked in 10 percent concentrated nitric acid
at 50°C for at least one hour, or (b) soaked in SO percent
concentrated nitric acid at room temperature for at least
two days; for arsenic and mercury, soaking for up to two
weeks at 50«C in 10 percent concentrated nitric acid might
be required. For plastics that might be damaged by strong
nitric acid, such as polycarbonate and possibly HOPE and
LDPE, soaking in 10 percent concentrated hydrochloric acicW
either in place of or before soaking in a nitric acid
solution, might be desirable.
3. Chromic acid must not be used to clean items that will be
used in analysis of metals.
4. Final soaking and cleaning of sample containers, labware,
and sampling apparatus must be performed in a class-100
clean room using metal-free acid and water. The solution
in an acid bath must be analyzed periodically to
demonstrate that it is metal-free.
5. After labware and sampling apparatus are cleaned, they may
be stored in a clean room in a weak acid bath prepared
using metal-free acid and water. Before use, the items
should be rinsed at least three times vith metal-free
water. After the final rinse, the items should be moved
immediately, with the open end pointed down, to a class-100.
clean bench. Items may be dried on a class-100 clean
bench; items must not be dried in an oven or with
laboratory towels. The sampling apparatus should be
assembled in-a class-100 clean room or bench and double-
bagged in metal-free polyethylene zip-type bags for
transport to the field; new bags are usually metal-free.
6. After sample containers are cleaned, they should be filled
with metal-free water that has been acidified to a pH of 2
with metal-free nitric acid (about 0.5 mL per liter) for
storage until use. At the time of sample collection, the
sample containers should be emptied and rinsed at least -
twice with the solution being sampled before the actual
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nickel, and zinc (Bruland et al. 1979; Nriagu et al. 1993).
b. The detection limit should be .less than ten percent of the
lowest concentration that is to be measured.
Avoiding interferences
a. Potential interferences must be assessed for the specific
instrumental analysis technique used and each metal to be
measured.
b. If direct analysis is used, the salt present in high-salinity
saltwater samples is likely to cause interference in most
instrumental techniques.
c. As stated above, extraction of the metal from the sample is
particularly useful because it simultaneously concentrates the
metal and eliminates potential matrix interferences.
Using blanks to assess contamination
a. A laboratory (procedural, method) blank consists of filling a
sample container with analyzed metal-free water and processing
(filtering, acidifying, etc.) the water through the laboratory
procedure in exactly the same way as a sample. A laboratory
blank must be included in each set of ten or fewer samples to
check for contamination in the laboratory, and must contain
less than ten percent of the lowest concentration that is to
be measured. Separate laboratory blanks must be processed for
the total recoverable and dissolved measurements, if both
measurements are performed.
b. A field (trip) blank consists of filling a sample container
with analyzed metal-free water in the laboratory, taking the
container to the site, processing the water through tubing,
filter, etc., collecting the water in a sample container, and
acidifying the water the same as a field sample. A field
blank must be processed for each sampling trip. Separate
field blanks must be processed for the total recoverable
measurement and for the dissolved measurement, if filtrations
are performed at the site. Field blanks vast be processed in
the laboratory the same as laboratory blanks.
Assessing accuracy
a. A calibration curve must be determined for each analytical run
and the calibration should be checked about every tenth
sample. Calibration solutions must be traceable back to a
certified standard from the U.S. EPA or the National Institute
of Science and Technology (HIST).
b. A blind standard or a blind calibration solution must be
included in each group of about twenty samples.
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sample.is placed in the sample container.
k. Field samples must be collected in a manner that eliminates
the potential for contamination from the sampling platform,
probes, etc. Exhaust from boats and the direction of wind and
water currents should be taken into account. The people who
collect the samples must be specifically trained on how to
collect field samples. After collection, all handling of
samples in the field that will expose the sample to air must
be performed in a portable class-100 clean bench or glove box.
1. Samples must be acidified (after filtration if dissolved metal
is to be measured) to a pH of less than 2, except that the pH
must be less than 1 for mercury. Acidification should be done
in a clean room or bench, and so it might be desirable to wait
and acidify samples in a laboratory rather than in the field.
If samples are acidified in the field, metal-free acid can be
transported in plastic bottles and poured into a plastic
container from which acid can be removed and added to samples
using plastic pipettes. Alternatively, plastic automatic
dispensers can be used.
B. Such things as probes and thermometers must not be put in
samples that are to be analyzed for metals. In particular, pH
electrodes and mercury-in-glass thermometers must not be used
if mercury is, to be measured. If pH is measured, it must be
done on a separate aliquot.
n. Sample handling should be minimized. For example, instead of
pouring a sample into a graduated cylinder to measure the
volume, the sample can be weighed after being poured into a
tared container; alternatively, the container from which the
sample is poured can be weighed. (For saltwater samples, the
salinity or density should be taken into account when weight
is converted to volume.)
o. Each reagent used must be verified to be metal-free. If
metal^free reagents are not commercially available, removal of
metals will probably be necessary.
p. For the total recoverable measurement, samples should be
digested in a class-100 bench, not in a metallic hood. If
feasible, digestion should be done in the sample container by
acidification and heating.
q. The longer the time between collection and analysis of
samples, the greater the chance of contamination, loss, etc.
r. Samples must be stored in the dark, preferably between 0 and
4°C with no air space in the sample container.
Achieving low detection limits
a. Extraction of the metal from the sample can be extremely
useful if it simultaneously concentrates the metal, and
eliminates potential matrix interferences. For example,
ammonium 1-pyrrolidinedithiocarbamate and/or diethylanmonium
diethyldithiocarbamate can extract cadmium, copper, lead,
-------
.nickel, and zinc (Bruland et al. 1979; Nriagu et al. 1993).
b-X.The.detectipn limit should be less than ten percent of the
concentration that is to be measured.
A Voiding interferences
;'• j ' : . •.•
a, potential interferences must be assessed for the specific
instrumental analysis technique used and each metal to be
measured.
b. If. direct analysis is used, the salt present in high-salinity
saltwater samples is likely to cause interference in most
instrumental -techniques.
c. As stated above, extraction of the metal from the sample is
- particularly useful because it simultaneously concentrates the
: metal and eliminates potential matrix interferences.
Usino blanks to assess contamination
a. A laboratory (procedural, method) blank consists of filling a
. sample container with analyzed metal-free water and processing
.(filtering, acidifying, etc.) the water through the laboratory
procedure in exactly the same way as a sample. A laboratory
blank must be included in each set of ten or fewer samples to
check for contamination in the laboratory, and must contain
less than ten percent of the lowest concentration that is to
be measured. Separate laboratory blanks must be processed for
the total recoverable and dissolved measurements, if both
measurements are performed.
b. A field (trip) blank consists of filling a sample container
' with analyzed metal-free water in the laboratory, taking the
container to the site, processing the water through tubing,
filter, etc., collecting the water in a sample container, and
acidifying the water the same as a field sample. A field
blank must be processed for each sampling trip. Separate
field blanks must be processed for the total recoverable
measurement and for the dissolved measurement, if filtrations
are. performed at the site. Field blanks must be processed in
the laboratory the same as laboratory blanks.
Assessing accuracy
a. A calibration curve must be determined for each analytical run
and -the calibration should be checked about every tenth
sample. Calibration solutions must be traceable back to a
certified standard from the U.S. EPA or the National Institute
of Science and Technology (MIST).
b. A blind standard or a blind calibration solution must be
included in each group of about twenty samples.
202
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c. At least'one of .the following must be included in each group
of about twenty samples:
1. A matrix spike (spiked sample; the method of known
additions).
2. A CRM, if one is available in a matrix that closely
approximates that of the samples. Values obtained for the
CRM must be within the published values.
The concentrations in blind standards and solutions, spikes, and
CRMs must not be more than 5 times the median concentration
expected to be present in the samples.
Assessing precision
a. A sampling replicate must be included with each set of samples
collected at each sampling location.
b. If the volume of the sample is large enough, replicate
analysis of at least one sample must be performed along with
each group of about ten samples.
Special considerations concerning the dissolved measurement
Whereas the total recoverable measurement is especially subject
to contamination during the digestion step, the dissolved
measurement is subject to both loss and contamination during the
filtration step.
a. Filtrations must be performed using acid-cleaned plastic
filter holders and acid-cleaned membrane filters. Samples
must not be filtered through glass fiber filters, even if the
filters have been cleaned with acid. If positive-pressure
filtration is used, the air or gas must be passed through a
Q.2-um in-line filter; if vacuum filtration is used, it must
be performed on a class-100 bench.
b. Plastic filter holders must be rinsed and/or dipped between
fNitrations, but they do not have to be soaked between
filtrations if all the samples contain about the same
concentrations of metal. It is best to filter samples from
low to high concentrations. A membrane filter must not be
used for more than one filtration. After each filtration, the
membrane filter-must-be removed and discarded, and the filter
holder must be either rinsed with metal-free water or dilute
acid and dipped in a metal-free acid bath or rinsed at least
twice with metal-free dilute acid; finally, the filter holder
must be rinsed at least twice with metal-free water.
c. For each sample to be filtered, the filter holder and membrane
filter must be conditioned with the sample, i.e., an initial
portion of the sample must be filtered and discarded.
The accuracy and precision of the dissolved measurement should be
-------
assessed periodically. A large volume of a buffered solution {
(such as aerated 0.05 N sodium bicarbonate) should be spiked so
that the concentration of the metal of interest is in the range
of the low concentrations that are to be measured. The total
recoverable concentration and the dissolved concentration of the
metal in the spiked buffered solution should be measured
alternately until each measurement has been performed at least
ten times. The means and standard deviations for the two
measurements should be the same. All values deleted as outliers
aust be acknowledged.
Reporting results
To indicate the quality of the data, reports of results of
measurements of the concentrations of metals must include a
description of the blanks, spikes, CPMs, replicates, and
standards that were run, the number run, and the results
obtained. All values deleted as outliers must be acknowledged.
Additional information
The items presented above are some of the important aspects of
"clean techniques"; some aspects of quality assurance and qua
control are also presented. This is not a definitive treatmen
of these topics; additional information that might be useful is
available in such publications as Patterson and Settle (1976) ,
Zief and Mitchell (1976), Bruland et al. (1979), Moody and Beary
(1982), Moody (1982), Bruland (1983), Adeloju and Bond (1985),
Barman and Yeats (1985), Byrd and Andreae (1986), Taylor (1987),
Sakamoto-Arnold (1987), Tramontane et al. (1987), Puls and
Barcelona (1989), Windom et al. (1991), U.S. EPA (1992), Horowitz
et al. (1992), and Nriagu et al. (1993).
References
Adeloju, S.B., and A.M. Bond. 1985. Influence of Laboratory
Environment on the Precision and Accuracy of Trace Element
Analysis. Anal. Chem. 57:1728-1733.
Berman, S.S., and P.A. Yeats. 1985. Sampling of Seawater for
Trace Metals. CRC Reviews in Analytical Chemistry 16:1-14.
Bruland, K.W., R.p. Franks, G.A. Knauer, and J.H. Martin. 1979.
Sampling and Analytical Methods for the Determination of Copper,
Cadmium, Zinc, and Nickel at the Kanogram per Liter Level in Sea
Water. Anal. Chim. Acta 105:233-245.
8
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' Bruland, K.W. 1983. Trace Elements in Sea-water. In: Chemical
Oceanography, Vol. 8. J.P. Riley and R. Chester, eds. Academic
Press, New York, NY. pp. 157-220.
Byrd, J.T., and M.O. Andreae. 1986. Dissolved and Particulate
Tin in North Atlantic Seawater. Marine Chemistry 19:193-200.
Horowitz, A.J., K.A. Elrick, and M.R. Colberg. 1992. The Effect
of Membrane Filtration Artifacts on Dissolved Trace Element
Concentrations. Water Res. 26:753-763.
Moody, J.R. 1982. NBS Clean Laboratories for Trace Element
Analysis. Anal. Chem. 54:1358A-1376A.
Moody, J.R., and E.S. Beary. 1982. Purified Reagents for Trace
Metal Analysis. Talanta 29:1003-1010.
Nriagu, J.O., G. Lawson, H.K.T. Hong, and J.M. Azcue. 1993. A
Protocol for Minimizing Contamination in the Analysis of Trace
Metals in Great Lakes Waters. J. Great Lakes Res. 19:175-182.
Patterson, C.C., and D.M. Settle. 1976. The Reduction in Orders
of Magnitude Errors in Lead Analysis of Biological Materials and
Natural Waters by Evaluating and Controlling the Extent and
Sources of Industrial Lead Contamination Introduced during Sample
Collection and Processing. In: Accuracy in Trace Analysis:
Sampling, Sample Handling, Analysis. P.D. LaFleur, ed. National
Bureau of Standards Spec. Publ. 422, U.S. Government Printing
Office, Washington, DC.
Puls, R.W., and M.J. Barcelona. 1989. Ground Water Sampling for
Metals Analyses. EPA/540/4-89/001. National Technical
Information Service, Springfield, VA.
Sakamoto-Arnold, C.M., A.K. Hanson, Jr., D.L. Huizenga, and' D.R.
Kester. 1987. Spatial and Temporal Variability of Cadmium in
Gulf Stream Warm-core Rings and Associated Waters. J. Mar. Res.
45:201-230.
Shiller, A.M., and E. Boyle. 1985. Dissolved Zinc in Rivers.
Nature 317:49-52.
Shiller, A.M., and E.A. Boyle. 1987. Variability of Dissolved
Trace Metals in the. Mississippi River. Geochim. Cosmochim. Acta
51:3273-3277.
Taylor, J.K. 1987. Quality Assurance of Chemical Measurements.
Lewis Publishers, Chelsea, MI.
Tramontane, J.M., J.R. Scudlark, and T.M. Church. 1987. A
Method for the Collection, Handling, and Analysis of Trace Metals
in Precipitation. Environ. Sci. Technol. 21:749-753.
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Trefry, J.H., T.A. Nelsen, R.P. Trocine, S. Metz., and T.w.
Vetter. 1986. Rapp. P.-v. Reun. Cons. int. Explor. Her.
186^277-288.
U.S. Environmental Protection Agency. 1983. Methods for
Chemical Analysis of Water and Wastes. EPA-600/4-79-020.
National Technical Information Service, Springfield, VA.
Sections 4.1.1, 4.1.3, and 4.1.4
U.S. Environmental Protection Agency. 1991. Methods for the
Determination of Metals in Environmental Samples. EPA-600/4-91-
010. National Technical Information Service, Springfield, VA.
U.S. Environmental Protection Agency. 1992. Evaluation of
Trace-Metal Levels in Ambient Waters and Tributaries to New
York/New Jersey Harbor for Waste Load Allocation. Prepared by
Battelle Ocean Sciences under Contract No. 68-C8-0105. -
Windom, H.L., J.T. Byrd, R.G. Smith, and F. Huan. 1991.
Inadequacy of NASQAN Data for Assessing Metals Trends in the
Nation's Rivers. Environ. Sci. Technol. 25:1137-1142. (Also see
Comment and Response, Vol. 25, p. 1940.)
Zief, M., and J.W. Mitchell. 1976. Contamination Control in
Trace Element Analysis. Chemical Analysis Series, Vol. 47.
Wiley, New York, NY.
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