April 2003
     Environmental Technology
     Verification Report


     WTW MEASUREMENT SYSTEMS
     CYANIDE ELECTRODE CN501
     with Reference Electrode R503D
     and Ion Pocket Meter 340i
                Prepared by
                 Battelle
                Battelle
              . . . Putting Technology To Work
            Under a cooperative agreement with


            U.S. Environmental Protection Agency
ElV ET1/ ElV

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                                  April 2003
Environmental Technology Verification
               Report

  ETV Advanced Monitoring Systems Center

  WTW MEASUREMENT SYSTEMS
    CYANIDE ELECTRODE CN501
    with Reference Electrode R503D
       and Ion Pocket Meter 340i
                 by
                Ryan James
                Amy Dindal
              Zachary Willenberg
                Karen Riggs
                Battelle
             Columbus, Ohio 43201

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                                       Notice
The U.S. Environmental Protection Agency (EPA), through its Office of Research and
Development, has financially supported and collaborated in the extramural program described
here. This document has been peer reviewed by the Agency. Mention of trade names or
commercial products does not constitute endorsement or recommendation by the EPA for use.
                                          11

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                                      Foreword
The U.S. Environmental Protection Agency (EPA) is charged by Congress with protecting the
nation's air, water, and land resources. Under a mandate of national environmental laws, the
Agency strives to formulate and implement actions leading to a compatible balance between
human activities and the ability of natural systems to support and nurture life. To meet this
mandate, the EPA's  Office of Research and Development provides data and science support that
can be used to solve environmental problems and to build the scientific knowledge base needed
to manage our ecological resources wisely, to understand how pollutants affect our health, and to
prevent or reduce environmental risks.

The Environmental Technology Verification  (ETV) Program has been established by the EPA to
verify the performance characteristics of innovative environmental technology across all media
and to report this objective information to permitters, buyers, and users of the technology, thus
substantially accelerating the entrance of new environmental  technologies into the marketplace.
Verification organizations oversee and report verification activities based on testing and quality
assurance protocols  developed with input from major stakeholders  and customer groups
associated with the technology  area. ETV consists of seven environmental technology centers.
Information about each of these centers can be found on the Internet at http://www.epa.gov/etv/.

Effective verifications of monitoring technologies are needed to assess environmental quality
and to supply cost and performance data to select the most appropriate technology for that
assessment. In 1997, through a  competitive cooperative agreement, Battelle was awarded EPA
funding and support to plan, coordinate, and conduct such verification tests for "Advanced
Monitoring Systems for Air, Water, and  Soil" and report the results to the community at large.
Battelle conducted this  verification under a follow-on to the original cooperative agreement.
Information concerning this specific environmental technology area can be found on the Internet
at http://www.epa.gov/etv/centers/centerl .html.
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                                 Acknowledgments
The authors wish to acknowledge the support of all those who helped plan and conduct the
verification test, analyze the data, and prepare this report. We would like to thank Billy Potter,
U.S. EPA, National Exposure Research Laboratory;  Ricardo DeLeon, Metropolitan Water
District of Southern California; William Burrows, U.S. Army Center for Environmental Health
Research; and Kenneth Wood, Du Pont Corporate Environmental Engineering Group, for their
technical review of the test/QA plan and for their careful review of this verification report. We
also would like to thank Allan Chouinard, City of Montpelier, VT; Gordon Brand, Des Moines,
IA, Water Works; Wylie Harper, City of Seattle, WA; John Morrill, City of Tallahassee, EL; and
Tom Scott, City of Flagstaff, AZ, water distribution facilities who provided post-treatment water
samples for evaluation.
                                          IV

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                                      Contents
                                                                                  Page


Notice	ii

Foreword  	  iii

Acknowledgments  	  iv

List of Abbreviations 	  viii

1 Background  	 1

2 Technology Description  	2

3 Test Design and Procedures 	3
       3.1 Introduction	3
       3.2 Reference Method	4
       3.3 Test Design  	4
       3.4 Test Samples  	4
            3.4.1 Quality Control Samples  	5
            3.4.2 Performance Test Samples	7
            3.4.3 Lethal/Near-Lethal Concentrations of Cyanide in Water	7
            3.4.4 Surface Water; Drinking Water from Around the U.S.;
                 and Columbus, OH, Drinking Water	7
       3.5 Test Procedure	9
            3.5.1 Calibration and Maintenance	9
            3.5.2 Sample Preparation  	  10
            3.5.3 Sample Identification	  10
            3.5.4 Sample Analysis	  11

4 Quality Assurance/Quality Control	  12
       4.1 Reference Method QC Results	  12
       4.2 Audits  	  15
            4.2.1 Performance Evaluation Audit	  15
            4.2.2 Technical Systems Audit	  15
            4.2.3 Audit of Data Quality	  16
       4.3 QA/QC Reporting 	  16
       4.4 Data Review  	  16

5 Statistical Methods and Reported Parameters	  18
       5.1 Accuracy	  18
       5.2 Precision 	  18
       5.3 Linearity 	  19
       5.4 Method Detection Limit  	  19

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       5.5  Inter-Unit Reproducibility	  19
       5.6  Lethal or Near-Lethal Dose Response	  19
       5.7  Field Portability	20
       5.8  Ease of Use  	20
       5.9  Sample Throughput	20

6 Test Results	21
       6.1  Calibration Results  	21
       6.2  Accuracy	22
       6.3  Precision  	22
       6.4  Linearity  	29
       6.5  Method Detection Limit  	30
       6.6  Inter-Unit Reproducibility	31
       6.7  Lethal or Near-Lethal Dose Response	31
       6.8  Field Portability	33
       6.9  Ease of Use  	33
       6.10 Sample Throughput	34

7 Performance Summary	35

8 References  	37
                                        Figures

Figure 2-1.  WTW Measurement Systems ISE  	2

Figure 3-1.  Sampling through Analysis Process	8

Figure 6-1.  Linearity Results 	30

Figure 6-2.  Inter-Unit Reproducibility Results	31



                                        Tables

Table 3-1.   Test Samples  	6

Table 4-1.   Reference Method QCS Results	 13

Table 4-2.   Reference Method LFM Analysis Results  	 14

Table 4-3.   Summary of Performance Evaluation Audit  	 15

Table 4-4.   Summary of Data Recording Process	 17

                                          vi

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Table 6-1.  Calibration Results	21

Table 6-2a. Cyanide Results from Performance Test Samples  	23

Table 6-2b. Cyanide Results from Surface Water	24

Table 6-2c. Cyanide Results from U.S. Drinking Water	25

Table 6-2d. Cyanide Results from Columbus, OH, Drinking Water	26

Table 6-3a. Percent Accuracy of Performance Test Sample Measurements  	27

Table 6-3b. Percent Accuracy of Surface Water Measurements  	27

Table 6-3c. Percent Accuracy of U.S. Drinking Water Measurements	27

Table 6-3d. Percent Accuracy of Columbus, OH, Drinking Water Measurements	28

Table 6-4a. Relative Standard Deviation of Performance Test Measurements	28

Table 6-4b. Relative Standard Deviation of Surface Water Measurements	28

Table 6-4c. Relative Standard Deviation of U.S. Drinking Water Measurements	29

Table 6-4d. Relative Standard Deviation of Columbus, OH, Drinking
           Water Measurements 	29

Table 6-5.  Results of Method Detection Limit Assessment 	30

Table 6-6a. Lethal/Near-Lethal Concentration Sample Results  	32

Table 6-6b. Percent Accuracy of Lethal/Near-Lethal Concentration Samples	32

Table 6-6c. Relative Standard Deviation of Lethal/Near-Lethal Concentration Samples .... 32
                                         vn

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                              List of Abbreviations
AMS
ASTM
ATEL
DPD
EPA
ETV
ID
ISE
KCN
L
LFM
MDL
mg
mL
mV
NaOH
PE
PT
QA
QA/QC
QC
QCS
QMP
RB
RPD
RSD
TSA
Advanced Monitoring Systems
American Society of Testing and Materials
Aqua Tech Environmental Laboratories
n,n-diethyl-p-phenylenediamine
U.S. Environmental Protection Agency
Environmental Technology Verification
identification
ion selective electrode
potassium cyanide
liter
laboratory-fortified matrix
method detection limit
milligram
milliliter
millivolt
sodium hydroxide
performance evaluation
performance test
quality assurance
quality assurance/quality control
quality control
quality control standard
quality management plan
reagent blank
relative percent difference
relative standard deviation
technical systems audit
                                        Vlll

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                                      Chapter 1
                                     Background
The U.S. Environmental Protection Agency (EPA) supports the Environmental Technology
Verification (ETV) Program to facilitate the deployment of innovative environmental tech-
nologies through performance verification and dissemination of information. The goal of the
ETV Program is to further environmental protection by substantially accelerating the acceptance
and use of improved and cost-effective technologies. ETV seeks to achieve this goal by provid-
ing high-quality, peer-reviewed data on technology performance to those involved in the design,
distribution, financing, permitting, purchase, and use of environmental technologies.

ETV works in partnership with recognized testing organizations; with stakeholder groups
consisting of buyers, vendor organizations, and permitters; and with the full participation of
individual technology developers. The program evaluates the performance of innovative tech-
nologies by developing test plans that are responsive to the needs of stakeholders, conducting
field or laboratory tests (as appropriate), collecting and analyzing data, and preparing peer-
reviewed reports. All evaluations are conducted in accordance with rigorous quality assurance
(QA) protocols to ensure that data of known and  adequate quality are generated and that the
results are defensible.

The EPA's  National Exposure Research Laboratory and its verification organization partner,
Battelle, operate the Advanced Monitoring Systems (AMS) Center under ETV. The AMS Center
recently evaluated the performance  of the WTW Measurement Systems Cyanide  Electrode
CN501 with the Reference Electrode R503D and Ion Pocket Meter 340i (referred to as the
WTW ion selective electrode [ISE] in this report) in detecting the presence of cyanide in water.
Portable cyanide analyzers were identified as a priority technology verification category through
the AMS Center stakeholder process.

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                                      Chapter 2
                               Technology Description
The objective of the ETV AMS Center is to verify the performance characteristics of
environmental monitoring technologies for air, water, and soil. This verification report provides
results for the verification testing of the WTWISE. Following is a description of the WTWISE,
based on information provided by the vendor. The information provided below was not verified
in this test.

The WTW ISE consists of a solid sensing element containing a mixture of inorganic silver
compounds bonded into the tip of an epoxy electrode body. When the sensing element is in
contact with a cyanide solution, silver ions dissolve from the membrane surface. Silver ions
within the sensing element move to the surface to replace the dissolved ions, establishing a
potential difference that is dependent on the cyanide concentration in the solution. Upon
calibration with solutions of known cyanide concentrations, these potential differences are
converted to concentrations and displayed on a digital readout when the WTW ISE is inserted
into an unknown solution.
                                  WTW ISE accessories include a hard carrying case, an
                                  electrode stand, a one-meter cable, and a reference
                                  electrode filling solution. List price for the provided items
                                  was $985 for the Ion Pocket Meter 340i and carrying case,
                                  $596 for the Cyanide Electrode CN501, and $121 for the
                                  electrode stand. The WTW ISE operates on four AA
                                  batteries and has dimensions of 6.9 x 3.2 x 1.5 inches.

                                  To analyze water samples for cyanide with the WTW ISE it
                                  has to first be calibrated using calibration solutions of
                                  known concentrations of cyanide in 0.100 M sodium
                                  hydroxide (NaOH). After calibration, a 50.0-mL sample is
                                  stirred with a magnetic stirrer; the WTW ISE is lowered
                                  into the sample; and, when a stable reading is attained, the
                                  concentration is recorded in milligrams per liter (mg/L).
Figure 2-1. WTW Measurement
Systems ISE

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                                      Chapter 3
                             Test Design and Procedures
3.1 Introduction
Cyanide can be present in various forms in water. This verification test focuses on the detection
of the free cyanide ion prepared using potassium cyanide (KCN) and referred to as simply
"cyanide" in this report. At high doses, this form of cyanide inhibits cellular respiration and, in
some cases, can result in death. Because of the toxicity of cyanide to humans, the EPA has set
0.200 mg/L as the maximum concentration of cyanide that can be present in drinking water. In
drinking and surface water under ambient conditions, cyanide evolves from aqueous hydrogen
cyanide, sodium cyanide, potassium cyanide, and other metal or ionic salts where cyanide is
released when dissolved in water. Heavier cyanide complexes (e.g., iron) are bound tightly,
requiring an acid distillation to liberate the toxic free cyanide ion,  a step not verified as part of
this test since field portability would have been eliminated. Because disassociation of the free
cyanide ion is unlikely under ambient conditions, the heavier salts are considered much less
toxic than simple cyanide salts such as potassium and sodium cyanide.

This verification test was conducted according to procedures specified in the Test/QA Plan for
Verification of Portable Analyzers for Detection of Cyanide in Water.,(1) The verification was
based on comparing the cyanide concentrations of water samples analyzed using the WTWISE
with cyanide concentrations analyzed using a laboratory-based reference method. The reference
method used during this verification test was EPA Method 335.1, Cyanides Amenable to
Chlorination.(2) This method was selected because it  measures the concentration of the cyanide
ion in water samples under ambient conditions, which is the same form  of cyanide that the
participating technologies are designed to measure. The WTW ISE was  verified by analyzing
performance test (PT), lethal/near-lethal concentration, surface, and drinking water samples. A
statistical comparison of the analytical results from the WTW ISE and the reference method
provided the basis for the quantitative performance evaluations.

The WTW ISE's performance was evaluated in terms of

•      Calibration results
•      Accuracy
•      Precision
•      Linearity
•      Method detection limit
•      Inter-unit reproducibility

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       Lethal or near-lethal dose response
       Field portability
       Ease of use
       Sample throughput.
3.2 Reference Method

Aqua Tech Environmental Laboratories (ATEL) in Marion, OH, performed the reference
analyses of all test samples. ATEL received the samples from Battelle labeled with an
identification number meaningful only to Battelle, performed the analyses, and submitted to
Battelle the results of the analyses without knowledge of the prepared or fortified concentration
of the samples.

The analytical results for the WTWISE were compared with the results obtained from analysis
using semi-automated colorimetry according to EPA Method 335.1.(2) For the reference method
analyses, the concentration of free cyanide was determined by the difference of two measure-
ments of total cyanide. One colorimetric determination was made after the free cyanide in the
sample had been chlorinated to cyanogen chloride, which degrades quickly, and a second was
made without chlorination. Typically, samples were sent to the reference laboratory for analysis
each testing day. The reference analysis was performed within 14 days of sample collection.
3.3 Test Design

Two WTW ISEs were tested independently between January 13 and February 4, 2003. All
preparation and analyses were performed according to the manufacturer's recommended
procedures. Some PT samples were reanalyzed on February 24, 2003, due to a laboratory error.
Because ISE technologies are not likely to be operated by non-technical users, operator bias was
not evaluated. All the results in this report were generated by a technical operator. The
verification test involved challenging the WTW ISE with a variety of test samples, including sets
of drinking and surface water samples representative of those likely to be analyzed by the WTW
ISE. The results from the WTW ISE were compared with the reference method to quantitatively
assess accuracy and linearity. Multiple aliquots of each test sample were analyzed separately to
assess the precision of the WTW ISE and the reference method.

Sample throughput was estimated based on the time required to prepare and analyze a sample.
Ease of use was based on documented observations by the operator and the Battelle Verification
Test Coordinator. The WTW ISE was used in a field environment as well as in a laboratory
setting to assess the impact of field conditions  on performance.
3.4 Test Samples

Test samples used in the verification test included quality control (QC) samples, PT samples,
lethal/near-lethal concentration samples, drinking water samples, and surface water samples

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(Table 3-1). The QC, PT, and lethal/near-lethal samples were prepared from purchased
standards. The PT and QC sample concentrations were targeted to the EPA maximum con-
taminant level in drinking water, which for cyanide is 0.200 mg/L.(3) The PT samples ranged
from 0.030 mg/L to 25.0 mg/L. The performance of the WTWISE also was quantitatively
evaluated with samples prepared in an American Society for Testing and Materials (ASTM)
Type n deionized water with cyanide concentrations up to 250 mg/L that could be lethal if
ingested. Two surface water sources (Olentangy River and Alum Creek Reservoir) were sampled
and analyzed. In addition, five sources of drinking water from around the United States and two
sources of Columbus, OH, drinking water were evaluated (Table 3-1).

3.4.1  Quality Control Samples

Prepared QC samples included both laboratory reagent blanks (RBs) and laboratory-fortified
matrix (LFM) samples (Table 3-1). The RB samples were prepared from ASTM type n
deionized water and were exposed to handling and analysis procedures identical to other
prepared samples, including the addition of all reagents. These samples were used to help ensure
that no sources of contamination were introduced in the sample handling and analysis
procedures. One reagent blank sample was analyzed for every batch of about 12 water samples.
The LFM samples were prepared as aliquots of drinking and surface water samples spiked with
KCN  as free cyanide to increase the cyanide concentration by 2.00 mg/L. The LFM spiking
concentration anticipated in the test/QA plan(1) was 0.200 mg/L. However, because
manufacturer's estimated limit of detection for the WTW ISE was reported as 0.200 mg/L, the
LFM samples for this technology were made at 2.00 mg/L. This was done so the WTW ISE was
not tested in drinking water matrices at concentrations near the detection limit. Before this
adjustment in the test/QA plan was made, the surface water  and two sets of drinking water
(Seattle, WA, and Montpelier, VT) LFM samples had already been analyzed after being fortified
at 0.200 mg/L. The drinking water samples were analyzed again after being fortified at
2.00 mg/L, but the surface water samples were not. Four LFM samples were analyzed for each
source of water. These samples were used to monitor the general performance of the reference
method to help determine whether matrix effects had an influence on the analytical results.

Quality control standards (QCSs) were used to ensure the proper calibration of the reference
instrument. The reference laboratory prepared the QCSs for  its use from a stock solution inde-
pendent from the one used to prepare the QCS analyzed using the WTW ISE. The QCSs for the
WTW ISE were purchased by Battelle from a commercial supplier and subject only to dilution
as appropriate. An additional independent QCS was used in a performance evaluation (PE) audit
of the reference method.

The reference method required that the concentration of each QCS be within 25% of the known
concentration. If the difference was larger that 25%, the data collected since the most recent
QCS were flagged; and proper maintenance was performed to regain accurate cyanide
measurement, according  to ATEL protocols. Section 4.1 describes these samples in more detail.

QCSs were analyzed (without defined performance expectations) by the WTW ISE to demon-
strate  their proper functioning to the operator. A QCS was analyzed before and after each sample
batch  (typically consisting of 12 water samples).

                                          5

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Table 3-1. Test Samples
Type of Sample
Quality Control
Performance Test
Lethal /
Near-Lethal
Surface Water
Drinking Water
from Around the
U.S.
Columbus, OH,
Area Drinking
Water
Sample Characteristics
RB
LFM
QCS
For the determination of
method detection limit
Cyanide
Cyanide
Cyanide
Cyanide
Cyanide
Cyanide
Cyanide
Cyanide
Cyanide
Cyanide
Cyanide
Alum Creek Reservoir
Olentangy River
Northwestern U.S.
Southwestern U.S.
Midwestern U.S.
Southeastern U.S.
Northeastern U.S.
Residence with city water
Residence with well water
Concentration
~0
0.200 or 2.00 mg/L
0.200 mg/L
0.800 mg/L
0.030 mg/L
0.100 mg/L
0.200 mg/L
0.400 mg/L
0.800 mg/L
5.00 mg/L
15.0 mg/L
25.0 mg/L
50.0 mg/L
100 mg/L
250 mg/L
Background
0.200 mg/L LFM
Background
0.200 mg/L LFM
Background
0.200 and 2.00 mg/L LFM
Background
2.00 mg/L LFM
Background
2.00 mg/L LFM
Background
2. 00 mg/L LFM
Background
0.200 and 2.00 mg/L LFM
Background
2.00 mg/L LFM
Background
2.00 mg/L LFM
No. of Samples
10% of all
4 per water
source (also
listed below)
10% of all
7
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
2
4
1
4
1
4
1
4
2
4
6
12
6
12

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3.4.2  Performance Test Samples

The PT samples (Table 3-1) were prepared in the laboratory using ASTM Type n deionized
water. The samples were used to determine the WTW ISE's accuracy, linearity, and detection
limit. Seven non-consecutive replicate analyses of a 0.800-mg/L solution were made to obtain
precision data with which to determine the method detection limit (MDL).(4) Seven other
solutions were prepared to assess the linearity over a 0.030- to 25.0-mg/L range of cyanide
concentrations. Four aliquots of each of these solutions were analyzed separately to assess the
precision of the analyzers.  The concentrations of the PT samples are listed in Table 3-1. The
operator analyzed the PT samples blindly and in random order to minimize bias.

3.4.3  Lethal/Near-Lethal Concentrations of Cyanide in Water

To assess the response of the WTW ISE when cyanide is present in drinking water at lethal and
near-lethal concentrations (>50 mg/L), samples were prepared in ASTM Type n deionized water
at concentrations of 50.0, 100, and 250 mg/L. Quantitative comparison of the results generated
by the WTW ISE to results from the reference method while analyzing such samples was done.
This is a change from the original test/QA plan.(1) Originally the ISE technologies were not to be
tested on the lethal/near-lethal concentration samples, but the ISE vendors recommended that the
technologies be tested quantitatively at these concentrations.

3.4.4 Surface Water; Drinking Waterfront Around the U.S.; and
Columbus, OH, Drinking Water

Water samples, including fresh surface water and tap water (well and local distribution sources)
were collected from a variety of sources and used to evaluate technology performance. Surface
water samples were collected from

•      Alum Creek Reservoir (OH)

•      Olentangy River (OH).

Drinking water samples were collected from

•      Local distribution source water (post-treatment) from five cities (Montpelier, VT;
       Des Moines, IA; Seattle, WA; Tallahassee, EL; and Flagstaff, AZ).

•      Columbus, OH, city water

•      Columbus, OH, well water.

The water samples collected as part of this verification test were not characterized in any way
(i.e., hardness, alkalinity, etc.) other than for cyanide concentration. Each sample was tested for
the presence of chlorine, dechlorinated if necessary, preserved with NaOH to a pH greater than
12.0, and split into two subsamples. Figure 3-1 is a diagram of the process leading from
sampling to aliquot analysis. One subsample was spiked with 0.200 or 2.00 mg/L of cyanide to

                                           7

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                       Dechlorinate
                           Background
                           Subsample
               J_
            Analyze
              four
           aliquots by
            reference
            method
          (background)
 Spike four
aliquots with
  0.2 mg/L
  cyanide
at reference
 laboratory
                           Analyze by
                            reference
                            method
                             (LFM)
                     _L
  Analyze
  aliquots
 by portable
  cyanide
  analyzer
(background)
                                           LFM
                                       Subsample
 Spike four
aliquots with
0.2 or 2 mg/L
  cyanide
                                       Analyze four
                                      50-mL aliquots
                                        by portable
                                         cyanide
                                         analyzer
                                          (LFM)
         Figure 3-1. Sampling through Analysis Process


provide LFM aliquots, and the other subsample remained unspiked (background). One 50-mL
aliquot was taken from each subsample and analyzed for cyanide by the WTWISE four separate
times (background samples). Also taken from the background subsample were eight aliquots
used for analysis by the reference method. Four of the aliquots were left unspiked and analyzed
by the reference method, and four of the aliquots were fortified with 0.200 mg/L of KCN as free
cyanide at the reference laboratory just before the reference analyses took place. This was done
to closely mimic the time elapsed between when the LFM samples were fortified with 0.200 or
2.00 mg/L KCN as free cyanide and when they were analyzed during the testing of the
participating technologies.

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To assess the reproducibility of background water samples, four replicates of Columbus, OH,
city and well water; Alum Creek samples; and Olentangy River samples were analyzed. None of
these samples had detectable concentrations of cyanide. Four LFM aliquots were prepared and
analyzed for every drinking and surface water source. To avoid replicating  samples with non-
detectable concentrations of cyanide, only one background aliquot of the drinking water sample
from around the country was analyzed.

Surface water from the Olentangy River and Alum Creek Reservoir and drinking water samples
collected at the five U.S. cities were shipped to Battelle for use in verification testing. Surface
water was collected near the shoreline by submerging containers no more than one inch below
the surface of the water. Representatives of each city's water treatment facility provided Battelle
a sample of water that had completed the water treatment process, but had not yet entered the
water distribution system. When the samples arrived at Battelle, they were  dechlorinated,
preserved, and split into background and  LFM subsamples, as described above for the rest of the
water samples.

Columbus, OH, city and well water samples were used to verify the field portability of the WTW
ISE. Approximately 20 liters of water were collected from an outside spigot at two participating
residences, one with well water and one with Columbus, OH, city water, and  split into three
samples. One sample was analyzed outdoors at the residence under the current weather condi-
tions. The weather conditions on the two  days of outdoor testing happened to be extremely cold
(air temperature ~0°C, sample temperature ~4 to 6°C). A second sample was equilibrated to
room temperature inside the residence (~17°C) and analyzed inside the residence. These two
samples were preserved,  split into background and LFM samples, and analyzed at the field
location as described for the other water samples (see Figure 3-1). For the third sample,  the
background  and LFM samples were prepared at the field location and transported to Battelle for
analysis in the laboratory five to six days  later. Because these analyses were done using the same
bulk water sample, a single  set of four background replicates was analyzed using the reference
method. The LFM sample fortified at the  field location and the LFM sample fortified at the
reference laboratory were analyzed by the reference method (see Table 4-2). These background
and LFM reference concentrations were compared to the results produced by the WTW ISE at
the indoor and outdoor field locations and the laboratory location.
3.5 Test Procedure

3.5.7  Calibration and Maintenance

The WTW ISE required a daily calibration using three calibration solutions. Solutions of 0.200,
2.00, 20.0, and 200 mg/L were used depending on the expected concentration of the samples to
be analyzed. The 2.00- and 20.0-mg/L calibration solutions were always used, but the third
calibration solution (0.200 or 200 mg/L) was chosen based on whether the samples were
expected to be on the high end of the calibration range or on the low end. For example, the
0.200-, 2.00-, and 20.0-mg/L calibration solutions were used most often for calibration because
most of the QC, PT, surface, and drinking water samples were below 20.0 mg/L cyanide.
However, when the water samples with lethal/near lethal concentrations (50.0 to 250 mg/L) were

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analyzed, the 200-mg/L calibration solution was used instead of the 0.200-mg/L calibration
solution. The operator also polished the WTWISE daily before calibration to ensure a clean
electrode surface. This was done by wetting a polishing strip (provided by the manufacturer)
with ASTM Type n deionized water and gently rubbing the face of the electrode in a single
direction for about 30 seconds. The operator attempted to polish each electrode in an identical
fashion.

3.5.2 Sample Preparation

QC and PT samples were prepared  from a commercially available National Institute of
Standards and Technology-traceable standard.  The standard was dissolved and diluted to
appropriate concentrations using ASTM Type n deionized water in Class A volumetric
glassware. The QC and PT samples were prepared at the start of testing, preserved with NaOH at
a pH greater than 12, and stored at 4°C  for the duration of the test.

Surface and drinking water samples were collected from the sources indicated in Section 3.4.4
and were stored in high-density polyethylene containers. Because free chlorine degrades cyanide
during storage, at the time of sample receipt, before NaOH preservation, all of the samples were
tested for free chlorine with potassium iodide starch paper. When the  samples collected as part
of this verification test were tested in this manner, none of them changed the color of the paper,
indicating that free chlorine was not present. However, when the LFM samples were analyzed
with the colorimetric technologies being evaluated, non-detectable results were  observed. To
further investigate the possibility of a chlorine interference, approximately 500 mL of each water
sample were added to separate beakers,  and one n,n-diethyl-p-phenylenediamine (DPD) chlorine
indicator tablet (Orbeco Analytical  Systems, Inc.) was added and crushed with a glass stirring
rod.  If the water turned pink, the presence of chlorine was indicated; and ascorbic acid was
added a few crystals at a time until  the color disappeared. All the drinking water samples were
tested in this manner; and, if the presence of chlorine was indicated, approximately 60 mg  of
ascorbic acid were added per liter of bulk sample to dechlorinate the sample.  A separate DPD
indicator test (as described above) was done to confirm adequate dechlorination of the sample
(indicated by no  color change). After dechlorination, 0.500 mL of alkaline reagent provided by
WTW ISE was added to 50.0 mL of each sample to be analyzed by the WTW ISE, according to
the manufacturer's specifications (see Figure 3-1). All the samples to  be analyzed by the
reference method were stored at 4°C and preserved with NaOH at a pH of greater than 12.0.

3.5.3 Sample Identification

Aliquots to be analyzed were drawn from the prepared standard solutions or from source and
drinking water samples and placed  in uniquely identified sample containers for subsequent
analysis. The sample containers were identified by a unique identification (ID) number. A
master log of the samples and sample ID numbers for each unit being verified was kept by
Battelle. The ID number, date, person collecting, sample location,  and time of collection were
recorded on a chain-of-custody form for all field samples.
                                           10

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3.5.4 Sample Analysis

The two WTW ISEs were tested independently. Each WTWISE analyzed the full set of samples,
and verification results were compared to assess inter-unit reproducibility. As shown in
Table 3-1, the samples included replicates of each of the PT, QC, surface water, and drinking
water samples. The analyses were performed according to the manufacturer's recommended
procedures.

Results were recorded manually on appropriate data sheets. In addition to the analytical results,
the data sheets and corresponding laboratory notebooks included records of the time required for
sample analysis and operator observations concerning the use of the WTW ISE (i.e., ease of use,
maintenance, etc.).

While the participating technologies were being tested,  a replicate sample set was being
analyzed by the reference laboratory. The reference instrument was operated according to the
recommended procedures in the instruction manual, and samples were analyzed according to
EPA Method  335.1(2) and ATEL standard operating procedures. Results from the reference
analyses were recorded electronically and compiled by ATEL into a report, including the sample
ID and the analyte concentration for each sample.
                                           11

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                                     Chapter 4
                        Quality Assurance/Quality Control
Quality assurance/quality control (QA/QC) procedures were performed in accordance with the
quality management plan (QMP) for the AMS Center(5) and the test/QA plan for this verification
test.(1)
4.1 Reference Method QC Results

Analyses of QC samples were used to document the performance of the reference method. To
ensure that no sources of contamination were present, RB samples were analyzed. The test/QA
plan stated that if the analysis of an RB sample indicated a concentration above the MDL for the
reference method, any contamination source was to be corrected and proper blank reading
achieved before proceeding with the verification test. Six reagent blank samples were analyzed,
and all of them were reported as below the 0.005-mg/L reporting limit for the reference method.

The reference instrument was calibrated initially according to the procedures specified in the
reference method. The accuracy of the reference method was verified with QCS samples analyzed
with the sample sets. One of two QCS samples, one with a concentration  of 0.150 mg/L and the
other with a concentration of 0.200 mg/L, were analyzed with each analytical batch
(approximately every 10 water samples). As required by the test/QA plan,(1) if the QCS analysis
differed by more than 25% from the true value of the standard, corrective action would be taken
before the analysis of more samples. As shown in Table 4-1, the QCS results were always within
the acceptable percent recovery range of 75 to 125%  and, in fact, were always between 90 and
110%.

Reference LFM samples were analyzed to confirm the proper functioning of the reference method
and to assess whether matrix effects influenced  the results of the reference method. The LFM
recovery (R) of the spiked solution was calculated from the following equation:

                                 R = Cs~C xlOO                                    (1)
where Cs is the reference concentration of the spiked sample, C is the reference concentration of
the background sample which, in this case, was always zero (results were below the MDL for the
reference method), and s is the fortified concentration of the cyanide spike. If the percent recovery
of an LFM fell outside the range of from 75 to 125%, a matrix effect or some other analytical
problem was suspected. As shown in Table 4-2, only the percent recovery for the LFM

                                           12

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Table 4-1. Reference
Date
1/13/2003
1/13/2003
1/15/2003
1/15/2003
1/16/2003
1/16/2003
1/17/2003
1/17/2003
1/20/2003
1/20/2003
1/21/2003
1/21/2003
1/27/2003
1/27/2003
1/28/2003
1/28/2003
1/29/2003
1/29/2003
1/30/2003
1/30/2003
1/30/2003
1/30/2003
1/31/2003
1/31/2003
1/31/2003
2/3/2003
2/3/2003
2/5/2003
2/5/2003
2/5/2003
2/6/2003
2/6/2003
2/7/2003
2/7/2003
2/10/2003
2/10/2003
2/11/2003
2/11/2003
2/11/2003
2/11/2003
2/12/2003
2/12/2003
2/12/2003
2/12/2003
2/13/2003
Method QCS Results
Analysis Result
0.157
0.200
0.142
0.180
0.151
0.194
0.154
0.190
0.190
0.158
0.153
0.201
0.143
0.187
0.146
0.186
0.149
0.189
0.139
0.187
0.139
0.188
0.146
0.150
0.196
0.152
0.189
0.147
0.149
0.194
0.151
0.198
0.154
0.199
0.148
0.181
0.141
0.180
0.136
0.191
0.159
0.201
0.153
0.201
0.158

Known QCS
Concentration (mg/L)
0.150
0.200
0.150
0.200
0.150
0.200
0.150
0.200
0.200
0.150
0.150
0.200
0.150
0.200
0.150
0.200
0.150
0.200
0.150
0.200
0.150
0.200
0.150
0.150
0.200
0.150
0.200
0.150
0.150
0.200
0.150
0.200
0.150
0.200
0.150
0.200
0.150
0.200
0.150
0.200
0.150
0.200
0.150
0.200
0.150

% Recovery
105
102
95
90
101
97
103
95
95
105
102
103
95
94
97
93
99
95
93
94
93
94
97
100
98
101
95
98
99
97
101
99
103
100
99
90
94
90
91
96
106
106
102
103
105
13

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Table 4-2. Reference Method LFM Analysis Results
       Sample Description
                   Average
   Fortified       Reference
Concentration  Concentration
    (mg/L)          (mg/L)
 % LFM   Reference
Recovery     RSD
Alum Creek LFM
Olentangy River LFM
Des Moines, IA, LFM
Flagstaff, AZ, LFM
Montpelier, VT, LFM
Tallahassee, FL, LFM
Seattle, WA, LFM
Columbus, OH, City Water LFM(a)
Columbus, OH, City Water LFM(b)
Columbus, OH, Well Water LFM(a)
Columbus, OH, Well Water LFM(b)
0.200
0.200
0.200
0.200
0.200
0.200
0.200
0.200
0.200
0.200
0.200
0.168
0.175
0.178
0.153
0.170
0.161
0.173
0.172
0.152
0.107
<0.005
84%
87%
89%
76%
85%
80%
87%
86%
76%
53%
0%
8%
2%
3%
12%
2%
2%
2%
4%
1%
13%
NA(C)
(a) Reference LFM sample spiked minutes before analysis by the reference method.
(b) Reference LFM sample spiked 8 to 10 days before analysis by the reference method.

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 4.2 Audits

 4.2.1 Performance Evaluation Audit

 A PE audit was conducted once to assess the quality of the reference measurements made in this
 verification test. For the PE audit, an independent standard was obtained from a different vendor
 than the one that supplied the QCSs. The relative percent difference (RPD) of the measured
 concentration and the known concentration was calculated using the following equation:
                                    RPD = — xlOO
                                            A
(2)
 where M is the absolute difference between the measured and known concentrations, and A is
 the mean of the same two concentrations. An RPD of less than 25% was required for the
 reference measurements to be considered acceptable. Failure to achieve this agreement would
 have triggered a repeat of the PE comparison. As shown in Table 4-3, all of the PE sample
 results were well within this required range.

 Table 4-3. Summary of Performance Evaluation Audit


Sample
PE-A
PE-B
PE-C
PE-D


Date of Analysis
2-12-2003
2-12-2003
2-12-2003
2-12-2003
Measured
Concentration
(mg/L)
0.216
0.213
0.218
0.203
Known
Concentration
(mg/L)
0.200
0.200
0.200
0.200

RPD
(%)
8
6
9
1
4.2.2  Technical Systems Audit

The Battelle Quality Manager performed a pre-verification test audit of the reference laboratory
(ATEL) to ensure that the selected laboratory was proficient in the reference analyses. This
entailed a review of the appropriate training records, state certification data, and the laboratory
QMP. The Battelle Quality Manager also conducted a technical systems audit (TSA) to ensure
that the verification test was performed in accordance with the test/QA plan(1) and the AMS
Center QMP.(5) As part of the audit, the Battelle Quality Manager reviewed the reference method
used, compared actual test procedures to those specified in the test/QA plan, and reviewed data
acquisition and handling procedures. Observations and findings from this audit were documented
and submitted to the Battelle Verification Test Coordinator for response. No findings were docu-
mented that required any corrective action. The records concerning the TSA are permanently
stored with the Battelle Quality Manager.
                                           15

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4.2.3  Audit of Data Quality

At least 10% of the data acquired during the verification test were audited. Battelle's Quality
Manager traced the data from the initial acquisition, through reduction and statistical analysis, to
final reporting, to ensure the integrity of the reported results. All calculations performed on the
data undergoing the audit were checked.
4.3 QA/QC Reporting

Each assessment and audit was documented in accordance with Sections 3.3.4 and 3.3.5 of the
QMP for the ETV AMS Center.(5) Once the assessment report was prepared, the Battelle
Verification Test Coordinator ensured that a response was provided for each adverse finding or
potential problem and implemented any necessary follow-up corrective action. The Battelle
Quality Manager ensured that follow-up corrective action was taken. The results of the TS A were
sent to the EPA.

4.4 Data Review

Records generated in the verification test were reviewed before these records were used to
calculate, evaluate, or report verification results. Table 4-4 summarizes the types of data
recorded. The review was performed by a technical staff member involved in the verification test,
but not the staff member who originally generated the record. The person performing the review
added his/her initials and the date to a hard copy of the record being reviewed.
                                            16

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Table 4-4. Summary of Data Recording Process
      Data to be
      Recorded
 Responsible
    Party
 Where Recorded
    How Often
    Recorded
Disposition of Data(a)
 Dates, times of test    Battelle
 events
 Test parameters        Battelle
 (meteorological
 conditions, analyte
 concentrations,
 location, etc.)

 Water sampling data   Battelle
 Reference method
 sample analysis,
 chain of custody,
 results
ATEL
                 Laboratory record
                 books
                 Laboratory record
                 books
                 Laboratory record
                 books
Laboratory record
book/data sheets or
data acquisition
system, as
appropriate	
                     Start/end of test; at
                     each change of a
                     test parameter
                    When set or
                    changed, or as
                    needed to
                    document stability


                    At least at the time
                    of sampling
Throughout sample
handling and
analysis process
Used to organize/
check test results;
manually incorporated
data into spreadsheets
as necessary

Used to organize/
check test results;
manually incorporated
data into spreadsheets
as necessary

Used to organize/
check test results;
manually incorporated
data into spreadsheets
as necessary

Excel spreadsheets
(a) All activities subsequent to data recording were carried out by Battelle.
                                                  17

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                                      Chapter 5
                  Statistical Methods and Reported Parameters
The statistical methods presented in this chapter were used to verify the performance parameters
listed in Section 3.1.
5.1 Accuracy

Accuracy was assessed relative to the results obtained from the reference analyses. Samples were
analyzed by both the reference method and the WTWISE. The results for each set of analyses
were averaged, and the accuracy was expressed in terms of a relative average bias (B) as
calculated from the following equation:


                                  S = = xlOO                                  (3)
                                      CR

where ~d  is the average difference between the readings from the WTW ISE and those from the
reference method, and CR is the average of the reference measurements. Accuracy was assessed
independently for each WTW ISE to determine inter-unit reproducibility.
5.2 Precision

The standard deviation (51) of the results for the replicate samples was calculated and used as a
measure of WTW ISE precision at each concentration.
                           S =
                                                   -,
                                      k=l
                                                     1/2
(4)
                                           18

-------
where n is the number of replicate samples, Ck is the concentration measured for the k"1 sample,
and c  is the average concentration of the replicate samples. The analyzer precision at each
concentration was reported in terms of the RSD, e.g.,
                                             xlOO                                  (5)
                                          c

5.3 Linearity
Linearity was assessed by linear regression, with the analyte concentration measured by the
reference method as independent variable and the reading from the WTWISE as dependent
variable. Linearity is expressed in terms of the slope, intercept, and the coefficient of
determination (r2).
5.4 Method Detection Limit

The MDL(4) for each WTW ISE was assessed from the seven replicate analyses of a fortified
sample with a cyanide concentration of approximately four times the vendor's estimated
detection limit (see Table 3-1).  The test/QA plan(1) called for the use of five times that
concentration, but the Code of Federal Regulations procedure for determining MDLs
recommends using a solution in the range of three to five times that concentration. Since the
0.800-mg/L PT solution was already prepared, and it was within the recommended range, it was
used for the MDL determination. The MDL was calculated from the following equation:

                                    MDL=txS                                    (6)
where t is the Student's value for a 99% confidence level, and S is the standard deviation of the
replicate samples. The MDL for each WTW ISE was reported separately.
5.5 Inter-Unit Reproducibility

The results obtained from two identical WTW ISEs were compiled independently for each WTW
ISE and compared to assess inter-unit reproducibility. The results were interpreted using a linear
regression of one WTW ISE's results plotted against the results produced by the other WTW ISE.
If the WTW ISEs function alike, the slope of such a regression should not differ significantly
from unity.
5.6 Lethal or Near-Lethal Dose Response

The accuracy of the WTW ISE for analyzing solutions at lethal/near-lethal concentrations was
assessed relative to the results obtained from the reference analyses. Samples were analyzed by

                                            19

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both the reference method and the WTWISE. The results for each set of analyses were averaged,
and the accuracy was expressed in terms of a relative average bias (B) as described in
Section 5.1.
5.7 Field Portability

The results obtained from the measurements made on drinking water samples in the laboratory
and field settings were compared to assess the accuracy of the measurements under the different
analysis conditions. The results were interpreted qualitatively since factors such as temperature
and matrix effects largely influenced the results.
5.8 Ease of Use

Ease of use was a qualitative measure of the user friendliness of the WTW ISE, including how
easy or hard the instruction manual was to use.
5.9 Sample Throughput

Sample throughput indicated the amount of time required to analyze a sample, including both
sample preparation and analysis.
                                           20

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                                        Chapter 6
                                       Test Results
The results of the verification test of the WTWISE are presented in this section.
6.1 Calibration Results

Table 6-1 shows the calibration results recorded throughout the verification test, including the
calibration solutions used and the actual slopes attained from the calibration linear regressions.
Upon calibration with three calibration solutions performed as suggested by the manufacturer's
instructions, the WTW ISE would automatically calculate and report the slope of the calibration
linear regression. The manufacturer suggested that this slope should be within the range of -54 to
-60 millivolt (mV) per tenfold increase in cyanide concentration. To simulate  the situation that a
field technician would be in when using  this technology, one calibration was performed; and then
the samples were analyzed, regardless of whether the slope value was within the recommended
range. As shown in Table 6-1, the slopes were usually in or within 10% of this range.

Table 6-1. Calibration Results
Date Calibration Solutions (mg/L)
1/14/2003
1/16/2003
1/17/2003
1/21/2003
1/27/2003
l/28/2003(b)
l/28/2003(b)
l/29/2003(b)
l/29/2003(b)
2/3/2003
2/4/2003
0.200, 2.00, 20.0
0.200, 2.00, 20.0
0.200, 2.00, 20.0
0.200, 2.00, 20.0
0.200, 2.00, 20.0
0.200, 2.00, 20.0
0.200, 2.00, 20.0
0.200, 2.00, 20.0
0.200, 2.00, 20.0
0.200, 2.00, 20.0
2.00, 20.0, 200
Unit#l(a)
(slope)
-58.2
-51.7
-55.2
-57.6
-57.9
-58.3
-53.4
-55.7
-53.1
-52.6
-51.9
Unit#2(a)
(slope)
-56.6
-56.1
-54.4
-56.0
-50.1
-58.4
-50.0
-52.8
-50.8
-55.1
-50.9
(a) Slopes are in units of mV per tenfold increase in cyanide concentration.
(b) ISE was calibrated twice on these two days because a calibration was completed before samples were run both
  indoors and outdoors.
                                             21

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6.2 Accuracy

Tables 6-2a-d present the measured cyanide results from analysis of the PT samples; surface
water; drinking water from various regions of the United States; and drinking water from
Columbus, OH, respectively, for both the reference analyses and the WTWISE. Results are
shown for both WTW ISEs that were tested (labeled as Unit #1 and #2).

Tables 6-3a-d present the percent accuracy of the WTW ISE results. The bias values were
determined according to Equation (3), Section 5.1. Bias was not calculated for background
samples with non-detectable concentrations of cyanide. However, in instances when the LFM
samples resulted in a non-detect reading due to a matrix effect, the bias was reported as 100%.
The bias values shown in Tables 6-3a-d can be summarized by the range of bias observed with
different sample sets.  For example, the biases ranged from 2 to 17% for the PT samples, 31 to
128% for the surface water samples, 2 to 39% for the drinking water samples from around the
country, and 3  to 44% for the Columbus, OH, water samples. Because of the low well water
reference LFM sample recovery (see Table 4-2), the well water biases were calculated using the
fortified concentration of 2 mg/L as the reference concentration rather than the result produced by
the reference method.

6.3 Precision

Tables 6-4a-d show the RSD of the cyanide analysis results for PT samples; surface water;
drinking water from around the U.S.; and drinking water from Columbus, OH, respectively, from
the WTW ISE and the reference method. Results are shown for both units that were tested. RSD
was not calculated for results reported as less than the MDL for WTW ISE. The RSD values
shown in Tables 6-4a-d can be summarized by the range of RSDs observed with different sample
sets. For example, the RSD ranged from 1 to 23% for the PT samples; 5 to 10% for the surface
water samples; 2 to 13% for the drinking water samples from around the country; and 2 to 10%
for all of the Columbus, OH, drinking water samples.
                                          22

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Table 6-2a. Cyanide Results
Concentration (mg/L)
0.030
0.030
0.030
0.030
0.100
0.100
0.100
0.100
0.200
0.200
0.200
0.200
0.400
0.400
0.400
0.400
0.800
0.800
0.800
0.800
5.00
5.00
5.00
5.00
15.0
15.0
15.0
15.0
25.0
25.0
25.0
25.0
from Performance
Ref. Cone.
(mg/L)
0.027
0.023
0.026
0.023
0.102
0.089
0.097
0.103
0.173
0.179
0.173
0.174
0.381
0.392
0.392
0.395
0.736
0.724
0.720
0.740
4.60
4.50
4.60
4.58
13.3
13.8
13.5
13.2
22.6
23.5
22.4
24.0
Test Samples
Unit #1
(mg/L)
<0.200
<0.200
<0.200
<0.200
<0.200
<0.200
<0.200
<0.200
0.200
0.192(a)
0.190(a)
0.150(a)
0.347
0.358
0.334
0.320
0.773
0.713
0.696
0.703
4.65
5.04
5.02
4.90
15.7
15.4
14.6
14.6
23.4
23.8
23.8
23.9

Unit #2
(mg/L)
<0.200
<0.200
<0.200
<0.200
<0.200
<0.200
<0.200
<0.200
0.185(a)
0.159(a)
0.147(a)
0.110(a)
0.383
0.370
0.335
0.352
0.723
0.637
0.607
0.613
4.63
4.64
4.61
4.83
13.4
12.9
13.1
12.6
21.1
21.3
21.3
22.3
(a)  Result below the WTW ISE detection limit of 0.200 mg/L, but still reported because of its close proximity to that
   limit.
                                                      23

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Table 6-2b.  Cyanide Results from Surface Water

Sample Description
Alum Creek Background
Alum Creek Background
Alum Creek Background
Alum Creek Background
Alum Creek LFMa
Alum Creek LFMa
Alum Creek LFMa
Alum Creek LFMa
Olentangy River Background
Olentangy River Background
Olentangy River Background
Olentangy River Background
Olentangy River LFM(a)
Olentangy River LFM(a)
Olentangy River LFM(a)
Olentangy River LFM(a)
Ref. Cone.
(mg/L)
<0.005
<0.005
<0.005
<0.005
0.166
0.183
0.173
0.151
<0.005
<0.005
<0.005
<0.005
0.174
0.178
0.171
0.176
Unit #1
(mg/L)
<0.200
<0.200
<0.200
<0.200
0.249
0.222
0.204
0.205
<0.200
<0.200
<0.200
<0.200
0.295
0.252
0.245
0.242
Unit #2
(mg/L)
<0.200
<0.200
<0.200
<0.200
0.357
0.373
0.340
0.335
<0.200
<0.200
<0.200
<0.200
0.430
0.389
0.394
0.379
(a)  These drinking water LFM samples were analyzed before the fortification amount of cyanide was changed from
   0.200 mg/L to 2 mg/L.
                                               24

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Table 6-2c. Cyanide Results from
Sample Description
Des Moines, IA, Background
Des Moines, IA, LFM
Des Moines, IA , LFM
Des Moines, IA, LFM
Des Moines, IA, LFM
Flagstaff, AZ, Background
Flagstaff, AZ, LFM
Flagstaff, AZ, LFM
Flagstaff, AZ, LFM
Flagstaff, AZ, LFM
Montpelier, VT, 0.200 mg/L LFM(a)
Montpelier, VT, 0.200 mg/L LFM(a)
Montpelier, VT, 0.200 mg/L LFM(a)
Montpelier, VT, 0.200 mg/L LFM(a)
Montpelier, VT, Background
Montpelier, VT, Background
Montpelier, VT, LFM
Montpelier, VT, LFM
Montpelier, VT, LFM
Montpelier, VT, LFM
Seattle, WA, 0.200 mg/L LFM(a)
Seattle, WA, 0.200 mg/L LFM(a)
Seattle, WA, 0.200 mg/L LFM(a)
Seattle, WA, 0.2 mg/L LFM(a)
Seattle, WA, Background
Seattle, WA, Background
Seattle, WA, LFM
Seattle, WA, LFM
Seattle, WA , LFM
Seattle, WA, LFM
Tallahassee, FL, Background
Tallahassee, FL, LFM
Tallahassee, FL, LFM
Tallahassee, FL, LFM
Tallahassee, FL, LFM
U.S. Drinking Water
Ref. Cone.
(mg/L)
<0.005
1.73
1.73
1.83
1.81
<0.005
1.57
1.32
SL00
1.69
0.167
0.176
0.168
0.168
<0.005
<0.005
1.67
1.76
1.68
1.68
0.177
0.174
0.170
0.172
<0.005
<0.005
1.77
1.74
1.70
1.72
<0.005
1.57
1.61
1.65
1.59

Unit #1
(mg/L)
<0.200
2.11
1.97
1.64
1.61
<0.200
1.87
1.69
1.72
1.68
0.192(c)
0.200
0.193(c)
0.196(c)
<0.200
<0.200
2.25
2.13
2.10
2.05
0.209
0.203
0.207
0.217
<0.200
<0.200
2.13
2.04
2.06
1.88
<0.200
1.82
1.65
1.59
1.57

Unit #2
(mg/L)
<0.200
1.26
1.28
1.08
1.21
<0.200
1.22
1.27
1.21
1.32
0.193(c)
0.200
0.191(c)
0.193(c)
<0.200
<0.200
1.45
1.43
1.29
1.21
0.208
0.214
0.214
0.216
<0.200
<0.200
1.42
1.23
1.26
1.17
<0.200
1.10
1.06
1.07
1.10
^ These drinking water LFM samples were analyzed before the fortification amount of cyanide was changed from
   0.200 mg/L to 2.00 mg/L.
^ SL= sample lost due to a laboratory error.

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Table 6-2d. Cyanide Results from Columbus, OH, Drinking Water

Sample Description
City Water Background - Outdoor Field Site
City Water Background - Indoor Field Site
City Water Background - Lab
City Water Background - Lab
City Water Background - Lab
City Water Background - Lab
City Water LFM - Outdoor Field Site
City Water LFM - Outdoor Field Site
City Water LFM - Outdoor Field Site
City Water LFM - Outdoor Field Site
City Water LFM - Indoor Field Site
City Water LFM - Indoor Field Site
City Water LFM - Indoor Field Site
City Water LFM - Indoor Field Site
City Water LFM - Lab
City Water LFM - Lab
City Water LFM - Lab
City Water LFM - Lab
Well Water Background - Outdoor Field Site
Well Water Background - Indoor Field Site
Well Water Background - Lab
Well Water Background - Lab
Well Water Background - Lab
Well Water Background - Lab
Well Water LFM - Outdoor Field Site
Well Water LFM - Outdoor Field Site
Well Water LFM - Outdoor Field Site
Well Water LFM - Outdoor Field Site
Well Water LFM - Indoor Field Site
Well Water LFM - Indoor Field Site
Well Water LFM - Indoor Field Site
Well Water LFM - Indoor Field Site
Well Water LFM - Lab
Well Water LFM - Lab
Well Water LFM - Lab
Well Water LFM - Lab
Ref. Conc.(a)
(mg/L)
<0.005
<0.005
<0.005
<0.005
<0.005
<0.005
1.76
1.67
1.65
1.78
1.76
1.67
1.65
1.78
1.76
1.67
1.65
1.78
<0.005
<0.005
<0.005
<0.005
<0.005
<0.005
1.00
1.21
1.14
0.91
1.00
1.21
1.14
0.91
1.00
1.21
1.14
0.91
Unit #1
(mg/L)
<0.200
<0.200
<0.200
<0.200
<0.200
<0.200
2.43
2.71
2.51
2.24
2.26
2.33
2.36
2.23
1.92
1.91
2.03
1.70
<0.200
<0.200
<0.200
<0.200
<0.200
<0.200
1.98
2.06
2.07
2.10
2.69
2.92
3.09
2.55
2.03
1.75
1.75
1.65
Unit #2
(mg/L)
<0.200
<0.200
<0.200
<0.200
<0.200
<0.200
2.38
2.38
2.13
2.26
2.15
2.07
2.22
2.49
2.25
2.63
2.22
2.25
<0.200
<0.200
<0.200
<0.200
<0.200
<0.200
1.58
1.66
1.64
1.63
2.65
2.89
2.57
2.27
2.40
2.38
2.29
2.08
 1 The same reference LFM samples are used for the outdoor, indoor, and laboratory analysis locations
                                             26

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Table 6-3a. Percent Accuracy of Performance Test Sample Measurements
Sample Concentration (mg/L)
0.030
0.100
0.200
0.400
0.800
5.00
15.0
25.0
Unit #1 (bias)
NA(a)
NA
12%
13%
4%
7%
12%
3%
Unit #2 (bias)
NA
NA
17%
8%
12%
2%
4%
7%
(a)
  NA = calculation of bias not appropriate when result was outside the detectable range of the WTW ISE.
Table 6-3b. Percent Accuracy of Surface Water Measurements

    Sample Description              Unit #1 (bias)                   Unit #2 (bias)
Alum Creek LFM                        31 %                            109%
Olentangy River LFM	48%	128%
Table 6-3c.  Percent Accuracy of U.S. Drinking Water Measurements
Sample Description
Montpelier, VT, 0.2.00 mg/L LFM(a)
Seattle, WA, 0.200 mg/L LFM(a)
Montpelier, VT, LFM
Seattle, WA, FM
Tallahassee, FL, LFM
Flagstaff, AZ, LFM
Des Moines, IA, LFM
Unit #1 (bias)
15%
2%
26%
17%
6%
39%
14%
Unit #2 (bias)
14%
2%
21%
27%
33%
32%
32%
(a) These drinking water LFM samples were analyzed before the drinking water fortification amount of cyanide was
  changed from 0.200 mg/L to 2.00 mg/L.
                                            27

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Table 6-3d. Percent Accuracy of Columbus, OH, Drinking Water Measurements
Sample Description
City Water LFM - Lab
City Water LFM - Indoor Field Site
City Water LFM - Outdoor Field Site
Well Water LFM - Lab(a)
Well Water LFM - Indoor Field Site(a)
Well Water LFM - Outdoor Field Site(a)
Unit #1 (bias)
12%
35%
44%
11%
40%
3%
Unit #2 (bias)
36%
30%
33%
14%
30%
19%

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Table 6-4c. Relative Standard Deviation of U.S. Drinking Water Measurements
Reference Method
Sample Description (RSD)
Montpelier, VT, 0.2 mg/L LFM(a)
Seattle, WA, 0.2 mg/L LFM(a)
Montpelier, VT, LFM
Seattle, WA, LFM
Tallahassee, FL, LFM
Flagstaff, AZ, LFM
Des Moines, IA, LFM
2%
2%
2%
2%
2%
12%
3%
Unit #1
(RSD)
2%
3%
4%
5%
7%
5%
13%
Unit #2
(RSD)
2%
2%
9%
8%
2%
4%
7%
(a)  These drinking water LFM samples were analyzed before the drinking water fortification amount of cyanide was
   changed from 0.200 mg/L to 2.00 mg/L.


Table 6-4d. Relative Standard Deviation of Columbus, OH, Drinking Water Measurements

Sample Description
City Water LFM - Lab
City Water LFM - Indoor Field Site
City Water LFM - Outdoor Field Site
Well Water LFM - Lab
Well Water LFM - Indoor Field Site
Well Water LFM - Outdoor Field Site
Reference Method
(RSD)
4%
4%
4%
13%
13%
13%
Unit #1
(RSD)
7%
2%
8%
9%
9%
2%
Unit #2
(RSD)
8%
8%
5%
6%
10%
2%
6.4 Linearity

The linearity of the WTWISE was assessed by using a linear regression of the PT results against
the reference method results (Table 6-2a). Figure 6-1 shows a scatter plot of the results from the
WTW ISE, versus the reference results.

A linear regression of the data in Figure 6-1 for the WTW ISE gives the following regression
equation:

        y (WTW ISE results in  mg/L)=0.99 (± 0.02) x (reference result in mg/L)
        + 0.075 (± 0.200) mg/L with r2=0.993 and N=64.

where the values in parentheses represent the 95% confidence interval of the slope and intercept.
The slope is not significantly different from unity, the intercept is not significantly different from
zero, and the r2 value is above 0.990, indicating that the WTW ISE was linear over the entire
range of PT concentrations  (0.030 to 25.0 mg/L).
                                            29

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                 30 -,
                                   10       15       20
                                     Reference cone. (mg/L)
                                                            25
                                                                    30
            Figure 6-1. Linearity Results
6.5 Method Detection Limit

The manufacturer's estimated detection limit for the WTWISE is 0.200 mg/L cyanide. The
MDL(4) was determined by analyzing seven replicate samples at a concentration of 0.800 mg/L.
Table 6-5 shows the results of the MDL assessment. The MDLs determined as described in
Equation (6) of Section 5.4 were 0.221 and 0.271 mg/L for Unit #1 and Unit #2, respectively.
Table 6-5.  Results of Method Detection Limit Assessment
MDL Cone. (mg/L)
0.800
0.800
0.800
0.800
0.800
0.800
0.800
Std Dev
t (n=7)
MDL
Unit #1 (RSD)
0.773
0.713
0.696
0.703
0.625
0.584
0.592
0.070
3.140
0.221
Unit #2 (RSD)
0.723
0.637
0.607
0.613
0.507
0.508
0.487
0.086
3.140
0.271
                                           30

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6.6 Inter-Unit Reproducibility

The inter-unit reproducibility of the WTWISE was assessed by using a linear regression of the
results produced by one WTW ISE plotted against the results produced by the other WTW ISE.
The results from all of the samples that had detectable amounts of cyanide (including the PT,
surface, and drinking water samples) were included in this regression.  Figure 6-2 shows a scatter
plot of the results from both analyzers.
                 30
             D)
             E,

             *
             .«
             c
25 -

20 -

15 -

10 -

 5 -

 0
                      y = 1.1126x+ 0.028
                          r2 = 0.9945
                    0
                      10        15
                      Unit #2 (mg/L)
20
25
            Figure 6-2.  Inter-Unit Reproducibility Results
A linear regression of the data in Figure 6-2 for the inter-unit reproducibility assessment gives the
following regression equation:

       y (Unit #1 result in mg/L)=1.113 (± 0.017) x (Unit #2 result in mg/L) + 0.028 (± 0.095)
       mg/L with r2=0.995 and N=92.

where the values in parentheses represent the 95% confidence interval of the slope and intercept.
While the slope is significantly different from unity, further analysis of the data revealed that the
deviation is heavily influenced by the 15.0- and 25.0-mg/L concentration levels. If only the PT
samples with cyanide concentrations of 0.200 through 5.00 mg/L are included in this regression,
the slope is unity, and the intercept is near zero. These data indicate that the two WTW ISEs
functioned  similarly to  one another except at the two highest PT sample concentration levels.  The
inclusion of these data caused approximately 10% deviation from a slope of unity.
6.7 Lethal or Near-Lethal Dose Response

Samples at 50.0-, 100-, and 250-mg/L concentrations (close to what may be lethal if a volume the
size of a typical glass of water was ingested) were prepared and analyzed by the WTW ISE.
Tables 6-6a-c present the measured cyanide results from analysis of the lethal/near-lethal
concentration samples for both the reference analyses and the WTW ISE. Results are shown in
Table 6-6a for both WTW ISEs. Table 6-6b presents the percent accuracy of the same results.  The
bias values were determined according to Equation (3), Section 5.1. The bias values shown in
Table 6-6b ranged from 3 to 34%, and the RSD of these results are shown in Table 6-6c and
                                            31

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ranged from 2 to 19%. The WTWISE performed as well when analyzing water samples at
lethal/non-lethal concentrations as it did at much lower concentrations.

Table 6-6a. Lethal/Near-Lethal Concentration Sample Results
Sample Concentration
(mg/L)
50.0
50.0
50.0
50.0
100
100
100
100
250
250
250
250
Ref. Cone.
(mg/L)
53.3
54.8
51.3
53.5
107
108
108
110
270
266
273
254
Unit #1
(mg/L)
58.5
54.6
55.2
52.1
SL(a)
116
115
105
438
383
316
285
Unit #2
(mg/L)
49.5
47.1
48.0
47.7
111
109
110
116
383
313
317
338
 1 SL = sample lost due to a laboratory error.
Table 6-6b. Percent Accuracy of Lethal/Near-Lethal Concentration Samples
Sample Concentration (mg/L)
50.0
100
250
Unit #1 (bias)
5%
6%
34%
Unit #2 (bias)
10%
3%
27%
Table 6-6c. Relative Standard Deviation of Lethal/Near-Lethal Concentration Samples
Prepared Concentration
(mg/L)
50.0
100
250
Reference Method
(RSD)
3%
1%
3%
Unit #1
(RSD)
5%
5%
19%
Unit #2
(RSD)
2%
3%
9%
                                         32

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6.8 Field Portability

The WTWISE was operated in laboratory and field settings during this verification test. It was
packaged in a hard plastic carrying case, which weighed about five pounds when fully loaded
with its contents. WTW also provided an electrode stand and a battery-powered magnetic stirrer
that were crucial for operating the analyzer in a field setting. These items are not routinely
provided with the WTW ISE and would have to be purchased separately. The electrode stand and
magnetic stirrer did not fit into the carrying case, but could easily be carried to the field. Tables
6-2d, 6-3d, and 6-4d show the results of the laboratory and field measurements. From an
operational standpoint, the WTW ISE was easily transported to the field setting, and the samples
were analyzed in the same fashion as they were in the laboratory. While no functional aspects of
the WTW ISE were compromised by performing the analyses in the field setting, close attention
had to be paid to bringing the calibration solutions to a temperature similar to the samples. This
was done by letting the sample and calibration solutions equilibrate overnight at the indoor field
location and for approximately one hour at the outdoor field location. The electrode equilibration
time was similar for samples analyzed indoors or outdoors.

Table 6-3d shows the bias of the samples analyzed in the field setting (indoors with sample
temperatures of approximately 16°C and outdoors with sample temperatures of 4 to 6°C) and of
the identical samples analyzed at the laboratory at approximately 20°C. The Columbus, OH, city
and well water samples were both dechlorinated as described in Section  3.5.2. In addition,
because the well water sample had a pungent odor, lead carbonate was added to a small aliquot
after NaOH preservation to check for the presence of sulfides. The lead carbonate did not turn
black. Such a color change would have indicated the presence of sulfides.

The Columbus, OH, well water LFM samples resulted in biases ranging  from 3 to 40%. Very
low biases (3 and 19%) were attained from the samples that were analyzed outside in frigid
temperatures. The biases of the well water sample analyzed indoors were 30 and 40%,  and those
measured in the laboratory were 11 and  14%. There was no clear trend for biases from indoor and
outdoor locations. The analyses performed outdoors by the WTW ISE resulted in biases as low or
lower than those performed indoors. The apparent matrix interference that affected the reference
LFM results did not seem to affect the results from the WTW ISE.  One possible reason is that the
LFM samples for the WTW ISE were fortified with 2.00 mg/L, ten times the fortification amount
for the other technologies being verified.

The Columbus, OH, city water LFM samples resulted in biases from 30 to 44%, except for the
12% bias of Unit #1 operated in the laboratory. These data indicate that the WTW ISE functioned
similarly in a laboratory and a field setting.
6.9 Ease of Use

The instruction manual for the WTW ISE was not easy to understand. It took consultation with a
WTW representative to assemble and operate the WTW ISE properly. However, after that initial
consultation with WTW, which included approximately a one-hour telephone call, the WTW ISE
was easy to operate. The WTW ISE required calibration and electrode polishing before every

                                           33

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sample set to ensure the most accurate measurements. Although the manual describes a five-point
calibration at 16 levels, the calibration concentrations were pre-programmed into the ISE meter
so only 0.200-, 2.00-, 20.0-, or 200-mg/L calibration solutions could be used. A sample could be
analyzed as long as the pH was above 12. No pH adjustment was necessary. One drawback of
this technology was that  the battery-powered stirrer would not operate at the slow speeds recom-
mended for use while making ISE measurements. There was some agitation of the calibration and
sample solutions when the stirrer was operating at its slowest setting.

6.10 Sample Throughput

The WTW ISE was calibrated  with three calibration solutions before performing any sample
analyses. Calibration took between 15 and 30 minutes, depending on the length of time it took for
solution equilibration with the electrode surface. Once the WTW ISE was calibrated, each sample
took approximately five minutes to attain a stable reading. A typical sample set of 12 analyses
plus calibration took approximately an hour and a half.
                                           34

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                                      Chapter 7
                               Performance Summary
Upon calibration with three calibration solutions performed as suggested by the manufacturer's
instructions, the WTWISE would automatically calculate and report the slope of the calibration
linear regression. The manufacturer suggested that this slope should be within the range of -54 to
-60 millivolt (mV) per tenfold increase in cyanide concentration. The slopes attained were usually
in this range or within 10% of this range. Regardless of whether the slope was within the
suggested range, one calibration was performed and then the samples were analyzed.

The biases for the WTW ISE ranged from 2 to 17% for the PT samples; 31 to 128% for the
surface water samples; 2 to 39% for the drinking water samples from around the country; and 3
to 44% for the Columbus, OH, drinking water samples.

The RSDs ranged from  1 to 23% for the PT samples; 5 to 10% for the surface water samples; 2 to
13% for the drinking water samples from around the country; and 2 to 10% for all of the
Columbus, OH, drinking water samples.

A linear regression of the linearity data for the WTW ISE gives the following regression equation:

       y (WTW ISE results in mg/L)=0.99 (± 0.02) x (reference result in mg/L)
       + 0.075 (± 0.200) mg/L with r2=0.993 and N=64.

where the values in parentheses represent the 95% confidence interval of the slope and intercept.
The slope is not significantly different from unity, the intercept is not significantly different from
zero, and the r2 value is above 0.99.

The MDLs for the WTW ISE were determined to be 0.221 and 0.271  mg/L.

A linear regression of the data for the inter-unit reproducibility assessment gives the following
regression equation:

       y (Unit #1 result in mg/L)=1.113 (± 0.017) x (Unit #2 result in mg/L) + 0.028 (± 0.095)
       mg/L with r2=0.995 and N=92.

where the values in parentheses represent the 95% confidence interval of the slope and intercept.
While the slope is significantly different from unity, further analysis of the data revealed that the
deviation is heavily influenced by the 15- and 25-mg/L concentration levels.
                                           35

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When analyzing lethal/near-lethal concentrations of cyanide, the bias values ranged from 3 to
34%, and the RSDs of these results ranged from 2 to 19%.

From an operational standpoint, the WTWISE was easily transported to the field setting, and the
samples were analyzed in the same fashion as they were in the laboratory. While no functional
aspects of the WTW ISE were compromised by performing the analyses in the field setting, close
attention had to be paid to bringing the calibration solutions to a temperature similar to the
samples.

The operator found the instruction manual for the WTW ISE difficult to understand. Consultation
with the supplier was required for explanation before the technician could properly assemble and
operate the WTW ISE. The WTW ISE required calibration and electrode polishing before every
sample set to ensure the most accurate measurements. The calibration concentrations were  pre-
programmed into the ISE meter so only 0.2-, 2-, 20-, or 200-mg/L calibration solutions could be
used. These solutions needed to be prepared and transported to the field. No pH adjustment was
necessary once the sample was preserved to a pH greater than  12.0. One drawback of the WTW
ISE was that the battery-powered stirrer would not operate at the slow speeds recommended.

The WTW ISE was calibrated with three calibration solutions before performing any sample
analyses. Calibration took between 15 and 30 minutes. Once the WTW ISE was calibrated, each
sample took approximately five minutes to attain a stable reading. A typical sample set of
12 analyses plus calibration took approximately an hour and a half.
                                           36

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                                    Chapter 8
                                    References
1.      Test/QA Plan for Verification of Portable Analyzers for Detection of Cyanide in Water,
       Battelle, Columbus, Ohio, January 2003.

2.      U.S. EPA Method 335.1, Cyanides Amenable to Chlorination, 1974, in "Methods for
       Chemical Analysis of Water and Wastes," EPA/600/4-79/020, March 1983.

3.      United States Environmental Protection Agency, National Primary Drinking Water
       Standards, EPA/816-F-02-013, July 2002.

4.      Code of Federal Regulations, Title 40, Part 136, Appendix B, Definition and Procedure
       for the Determination of the Method Detection Limit-Revision 1.11.

5.      Quality Management Plan (QMP)for the ETV Advanced Monitoring Systems Center,
       Version 4.0, U.S. EPA Environmental Technology Verification Program, Battelle,
       Columbus, Ohio, December 2002.
                                         37

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