July 2004
Environmental Technology
Verification Report
YSI Incorporated
6600 EDS Multi-Parameter
Water Quality Probe/Sonde
Prepared by
Battelle
Bafteiie
The Business of Innovation
In cooperation with the
National Oceanic and Atmospheric Administration
Under a cooperative agreement with
&EPA U.S. Environmental Protection Agency
ETV EtV ElV
-------
July 2004
Environmental Technology Verification
Report
ETV Advanced Monitoring Systems Center
YSI Incorporated
6600 EDS Multi-Parameter
Water Quality Probe/Sonde
by
Jeffrey Myers
Amy Dindal
Zachary Willenberg
Karen Riggs
Battelle
Columbus, Ohio 43201
and
Paul Pennington
Michael Fulton
Geoffrey Scott
NOAA CCEHBR
Charleston, South Carolina 29412
-------
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 and recommended for public release.
Mention of trade names or commercial products does not constitute endorsement or
recommendation by the EPA for use.
The National Oceanic and Atmospheric Administration (NOAA) does not approve, recommend,
or endorse any proprietary product or material mentioned in this publication. No reference shall
be made to NOAA in any advertising or sales promotion which would indicate or imply that
NOAA approves, recommends, or endorses any proprietary product or proprietary material
mentioned herein.
11
-------
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. Under a cooperative agreement, Battelle has received EPA funding 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. Information concerning this
specific environmental technology area can be found on the Internet at
http ://www. epa. gov/etv/centers/center 1. html.
111
-------
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 the National
Oceanic and Atmospheric Administration's (NOAA) National Ocean Service, National Centers
for Coastal Ocean Science staff at the Center for Coastal Environmental Health and
Biomolecular Research. In addition, NOAA's Coastal Service Center is acknowledged for
providing access to dock facilities on a tributary of Charleston Harbor for the saltwater testing,
as well as the South Carolina Department of Natural Resources for the use of its land and pier.
We also acknowledge the assistance of the ETV Advanced Monitoring Systems Center
stakeholders Christine Kolbe of the Texas Commission on Environmental Quality, Vito Minei
and Robert Waters of the Suffolk County New York Department of Health Services, and
Paul Pennington and Geoff Scott of NOAA, as well as James O'Dell and Linda Sheldon of the
U.S. Environmental Protection Agency.
iv
-------
Contents
Page
Notice ii
Foreword iii
Acknowledgments iv
List of Abbreviations ix
1 Background 1
2 Technology Description 2
3 Test Design and Procedures 4
3.1 Introduction 4
3.2 Test Site Characteristics 4
3.3 Test Design 5
3.3.1 Saltwater Testing 8
3.3.2 Freshwater Testing 9
3.3.3 Mesocosm Testing 10
3.4 Reference Measurements 10
4 Quality Assurance/Quality Control 12
4.1 Instrument Calibration 12
4.2 Field Quality Control 12
4.3 Sample Custody 12
4.4 Audits 13
4.4.1 Performance Evaluation Audit 13
4.4.2 Technical Systems Audit 14
4.4.3 Audit of Data Quality 14
4.5 QA/QC Reporting 14
4.6 Data Review 15
5 Statistical Methods 16
5.1 Calibration Check Accuracy 16
5.2 Relative Bias 16
5.3 Precision 17
5.4 Linearity 17
5.5 Inter-Unit Reproducibility 17
v
-------
6 Test Results 18
6.1 Calibration Check Accuracy 21
6.2 Relative Bias 21
6.3 Precision 32
6.4 Linearity 34
6.5 Inter-Unit Reproducibility 41
6.6 Other Factors 61
6.6.1 Ease of Use 61
6.6.2 Data Completeness 61
7 Performance Summary 62
8 References 63
Appendix A Reference Sample and Probe Readings A-l
Figures
Figure 2-1. YSI 6600 EDS 2
Figure 3-1. Saltwater Site 6
Figure 3-2. Freshwater Site 6
Figure 3-3. Mesocosm Tank 7
Figure 3-4. Saltwater Deployment 8
Figure 6-1. 6600 EDS Prior to Deployment 18
Figure 6-2. 6600 EDS After Saltwater Deployment 19
Figure 6-3. Cleaned and Reconditioned 6600 EDSs in Storage Tank Used
Between Deployments 20
Figure 6-4. 6600 EDS After Freshwater Deployment 20
Figure 6-5a. Relative Bias Data for DO (Saltwater) 25
Figure 6-5b. Relative Bias Data for DO (Mesocosm) 25
Figure 6-5c. Relative Bias Data for Specific Conductivity (Saltwater) 26
Figure 6-5d. Relative Bias Data for Specific Conductivity (Mesocosm) 26
Figure 6-5e. Relative Bias Data for Temperature (Saltwater) 27
Figure 6-5f. Relative Bias Data for Temperature (Mesocosm) 27
Figure 6-5g. Relative Bias Data for pH (Saltwater) 28
Figure 6-5h. Relative Bias Data for pH (Mesocosm) 28
Figure 6-5i. Relative Bias Data for Turbidity (Saltwater) 29
Figure 6-5j. Relative Bias Data for Turbidity (Mesocosm) 29
Figure 6-5k. Relative Bias Data for Chlorophyll (Saltwater) 30
Figure 6-51. Relative Bias Data for Chlorophyll (Mesocosm) 30
Figure 6-6a. Linearity Data for DO (Saltwater) 35
Figure 6-6b. Linearity Data for DO (Mesocosm) 35
Figure 6-6c. Linearity Data for Specific Conductivity (Saltwater) 36
Figure 6-6d. Linearity Data for Specific Conductivity (Mesocosm) 36
Figure 6-6e. Linearity Data for Temperature (Saltwater) 37
vi
-------
Figure 6-6f. Linearity Data for Temperature (Mesocosm) 37
Figure 6-6g. Linearity Data for pH (Saltwater) 38
Figure 6-6h. Linearity Data for pH (Mesocosm) 38
Figure 6-6i. Linearity Data for Turbidity (Saltwater) 39
Figure 6-6j. Linearity Data for Turbidity (Mesocosm) 39
Figure 6-6k. Linearity Data for Chlorophyll (Saltwater) 40
Figure 6-61. Linearity Data for Chlorophyll (Mesocosm) 40
Figure 6-7a. Inter-Unit Reproducibility Data for DO During Saltwater Tests 43
Figure 6-7b. Inter-Unit Reproducibility Data for DO During Freshwater Tests 44
Figure 6-7c. Inter-Unit Reproducibility Data for DO During Mesocosm Tests 45
Figure 6-8a. Inter-Unit Reproducibility Data for Specific Conductivity
During Saltwater Tests 46
Figure 6-8b. Inter-Unit Reproducibility Data for Specific Conductivity
During Freshwater Tests 47
Figure 6-8c. Inter-Unit Reproducibility Data for Specific Conductivity
During Mesocosm Tests 48
Figure 6-9a. Inter-Unit Reproducibility Data for Temperature During Saltwater Tests 49
Figure 6-9b. Inter-Unit Reproducibility Data for Temperature During Freshwater Tests .... 50
Figure 6-9c. Inter-Unit Reproducibility Data for Temperature During Mesocosm Tests .... 51
Figure 6-10a. Inter-Unit Reproducibility Data for pH During Saltwater Tests 52
Figure 6-10b. Inter-Unit Reproducibility Data for pH During Freshwater Tests 53
Figure 6-10c. Inter-Unit Reproducibility Data for pH During Mesocosm Tests 54
Figure 6-1 la. Inter-Unit Reproducibility Data for Turbidity During Saltwater Tests 55
Figure 6-1 lb. Inter-Unit Reproducibility Data for Turbidity During Freshwater Tests 56
Figure 6-1 lc. Inter-Unit Reproducibility Data for Turbidity During Mesocosm Tests 57
Figure 6-12a. Inter-Unit Reproducibility Data for Total Chlorophyll
During Saltwater Tests 58
Figure 6-12b. Inter-Unit Reproducibility Data for Total Chlorophyll
During Freshwater Tests 59
Figure 6-12c. Inter-Unit Reproducibility Data for Total Chlorophyll
During Mesocosm Tests 60
Tables
Table 2-1. 6600 EDS Range, Resolution, and Accuracy as Provided by the Vendor 3
Table 3-1. Water Characteristics at the Test Sites 5
Table 3-2. Verification Test Schedule 7
Table 3-3. Schedule for Saltwater Sample Collection—Tributary of Charleston Harbor .... 9
Table 3-4. Schedule for Freshwater Sample Collection—Hollings Wetlands 9
Table 3-5. Schedule for Mesocosm Sample Collection 10
Table 3-6. Maximum Sample Holding Times 11
Table 4-1. Replicate Analysis QC Criteria 13
Table 4-2. Expected Values for Field Blanks 13
Table 4-3. Summary of Performance Evaluation Audits 13
Table 4-4. Summary of Data Recording Process 15
Table 6-1. Calibration Check Accuracy 22
vii
-------
Table 6-2. Average Relative Bias Results for YSIAA and YSIAB 31
Table 6-3. Measurements and Percent Relative Standard Deviations for
YSI AA and YSI AB During Stable Mesocosm Operation 33
Table 6-4. Average Absolute Difference Between YSI AA and YSI AB
Readings for Each Parameter at Each Deployment Location 42
Table 6-5. Installation, Operation, and Maintenance Activities 61
Table 7-1. Summary of Performance 62
viii
-------
List of Abbreviations
AMS Advanced Monitoring Systems
CCEHBR Center for Coastal Environmental Health and Biomolecular Research
cm centimeter
DAS data acquisition system
DO dissolved oxygen
EDS Extended Deployment System
EPA U.S. Environmental Protection Agency
ETV Environmental Technology Verification
L liter
|_ig microgram
mg milligram
mS millisiemen
NIST National Institute of Standards and Technology
NOAA National Oceanic and Atmospheric Administration
NTU nephelometric turbidity unit
PE performance evaluation
QA/QC quality assurance/quality control
QMP Quality Management Plan
RSD relative standard deviation
TSA technical systems audit
IX
-------
Chapter 1
Background
The U.S. Environmental Protection Agency (EPA) has created 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 YSI Incorporated 6600 Extended Deployment System
(EDS).
1
-------
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 6600 EDS water probe by YSI Incorporated. Following
is a description of the 6600 EDS, based on information provided by the vendor. The information
provided below was not verified in this test.
The 6600 EDS (Figure 2-1) is a multi-parameter
water probe/sonde capable of measuring dissolved
oxygen (DO), specific conductivity, temperature,
pH, turbidity, and chlorophyll (total in vivo).
The 6600 EDS is maintained free of fouling by
the Clean Sweep™ universal wiper assembly, as
well as by individual optical wipers. 6600 EDS
sensors are field-replaceable and integrate with
data collection platforms. Flash memory prevents
data loss, and C-cell battery power allows long-
term deployment. The tested 6600 EDS was
coated with YSFs optional anti-fouling paint.
Figure 2-1. YSI 6600 EDS
$10,000. The range, resolution, and accuracy
listed in Table 2-1 for the parameters tested.
The outer diameter of the 6600 EDS is
8.9 centimeters (cm) (3.5 inches). It is 52 cm
(20.4 inches) long and weighs 2.7 kilograms (six
pounds). The 6600 EDS sells for approximately
rf the 6600 EDS, as indicated by the vendor, are
2
-------
Table 2-1. 6600 EDS Range, Resolution, and Accuracy as Provided by the Vendor
Parameter
Range
Resolution
Accuracy
DO %
Saturation
0 to 500%
0.1%
0 to 200% ±2%; 200 to 500%
±6% of reading
DO
0 to 50 milligrams/liter
(mg/L)
0.01 mg/L
0 to 20 mg/L ±0.2 mg/L
20 to 50 mg/L ±0.6 mg/L
Specific
conductivity
0 to 100 millisiemen
(mS)/cm
0.001 to 0.1 mS/cm
±0.5% of reading +0.001
mS/cm
Temperature
-5 to +45 °C
0.01°C
±0.15°C
pH
Oto 14
0.01
±0.2
Turbidity
0 to 1,000 nephelometric
turbidity unit (NTU)
0.1 NTU
±5% of reading or 2 NTU,
whichever is greater
Chlorophyll
0 to 400 microgram (|ig)/L
0 to 100% fluorescence
0.1 |ig/L chlorophyll
0.1% fluorescence
NA
NA = not applicable (measures total fluorescence)
3
-------
Chapter 3
Test Design and Procedures
3.1 Introduction
This verification test was conducted according to procedures specified in the Test/QA Plan for
Long-Term Deployment of Multi-Parameter Water Quality Probes/Sondes m The purpose of the
verification test was to evaluate the performance of the 6600 EDS under realistic operating
conditions. The 6600 EDS was evaluated by determining calibration check accuracy and by
comparing 6600 EDS measurements with standard reference measurements and measurements
from handheld calibrated probes. Two 6600 EDSs were deployed in saltwater, freshwater, and
laboratory environments near Charleston, South Carolina, during a 3 '/2-month verification test.
Water quality parameters were measured both by the 6600 EDSs and by reference methods
consisting of collocated field-portable instrumentation and analyses of collected water samples.
During each phase, performance was assessed in terms of calibration check accuracy, relative
bias, precision, linearity, and inter-unit reproducibility for each 6600 EDS.
The performance of the 6600 EDS was verified in terms of the following parameters:
¦ DO
¦ Specific conductivity
¦ Temperature
¦ pH
¦ Turbidity
¦ Chlorophyll (total in vivo).
3.2 Test Site Characteristics
The three test sites used for this verification were selected in an attempt to expose the 6600 EDS
to the widest possible range of conditions while conducting an efficient test. The three sites
included one saltwater, one freshwater, and one controlled location. Approximate ranges for the
target parameters at each of the test sites as determined by reference measurements are given in
Table 3-1.
4
-------
Table 3-1. Water Characteristics at the Test Sites
Saltwater Freshwater Mesocosm
Parameter
Low
High
Low
High
Low
High
DO
3 mg/L
6 mg/L
6.8 mg/L
11.2 mg/L
9.3 mg/L
12.1 mg/L
Specific
conductivity
31 mS/cm
41 mS/cm
0.27 mS/cm
29.3 mS/cm
0.5 mS/cm
28 mS/cm
Temperature
20°C
28°C
11°C
27°C
9°C
16°C
pH
7.2
7.8
6.9
7.5
7.1
8.5
Turbidity
8 NTU
37 NTU
1.7 NTU
3.6 NTU
0.4 NTU
15 NTU
Chlorophyll
(total fluorescence)
2 |_ig/L
5 |ig/L
0.0 |ig/L
16 |ig/L
0.2 |ig/L
1.4 |ig/L
3.3 Test Design
The verification test was designed to assess the performance of multi-parameter water probes
and was closely coordinated with the National Oceanic and Atmospheric Administration
(NOAA) through the Center for Coastal Environmental Health and Biomolecular Research
(CCEHBR). The test was conducted in three phases at a saltwater site in a tributary of
Charleston Harbor; a freshwater site at the Hollings wetland on the CCEHBR campus; and a
controlled site at the CCEHBR mesocosm facility in Charleston, South Carolina. At each test
site, two 6600 EDSs were deployed as close to each other as possible to assess inter-unit
reproducibility. The first phase of the test was conducted at the saltwater site (Figure 3-1). The
CCEHBR campus has access to the tributary of Charleston Harbor site, which is a
predominantly tidal body of water that receives some riverine input; its salinities range from 20
to 35 parts per thousand. The second phase of the test was conducted at the freshwater site
(Figure 3-2). The freshwater site was a wetlands area near the Hollings Marine Research
Laboratory, located on the CCHEBR campus. The third phase was conducted at the CCEHBR's
mesocosm facility (Figure 3-3). This facility contains modular mesocosms that can be classified
as "tidal" or "estuarine." The mesocosm phase included both saltwater and freshwater
conditions.
The precision measurements were performed before the 6600 EDS was deployed into the
saltwater environment. The 6600 EDS was placed in a tank of saline water inside the NOAA
laboratory. While in this stable environment, the 6600 EDS sampled at a rate of once per minute
for approximately 30 minutes to collect data used in the percent relative standard deviation
(RSD).
The schedule for the various testing activities is given in Table 3-2.
5
-------
Figure 3-1. Saltwater Site
Figure 3-2. Freshwater Site
6
-------
Figure 3-3. Mesocosm Tank
Table 3-2. Verification Test Schedule
Activity
Date
Vendor setup for saltwater phase
October 1, 2003
Begin saltwater phase
October 2, 2003
End saltwater phase
October 29, 2003
Set up freshwater phase
October 31, 2003
Begin freshwater phase
November 4, 2003
End freshwater phase
December 8, 2003
Vendor setup for mesocosm
December 9, 2003
Begin mesocosm phase
December 10, 2003
End mesocosm phase
January 5, 2004
Return all equipment
January 8, 2004
7
-------
3.3.1 Saltwater Testing
The saltwater phase lasted for 28 days, during which time the 6600 EDS monitored the naturally
occurring range of the target parameters 24 hours per day at 15-minute measurement intervals.
Dockside reference measurements were made for DO, specific conductivity, temperature, and
pH, while reference samples for turbidity and chlorophyll were collected and returned to the
laboratory for analysis. Figure 3-4 shows the 6600 EDSs at the pier. The 6600 EDSs were
mounted on iron posts that were driven into the river bed. The 6600 EDSs were approximately
0.5 meters apart in the shallows of the tidal river. Reference samples were collected throughout
the day during the test. For the duration of this phase, the 6600 EDSs were deployed at depths
between approximately one and 10 feet, varying according to the tide. Table 3-3 shows the times
and numbers of samples taken throughout the saltwater phase.
Figure 3-4. Saltwater Deployment
8
-------
Table 3-3. Schedule for Saltwater Sample Collection—Tributary of Charleston Harbor
Test Day Date # Reference Samples Activities
1 10/2/2003 Deploy 6600 EDSs
7 10/8/2003 2
8 10/9/2003 4
14 10/15/2003 4
15 10/16/2003 4
22 10/23/2003 6
26 10/27/2003 9
27 10/28/2003 6
28 10/29/2003 6
29 10/30/2003 Retrieve 6600 EDSs
3.3.2 Freshwater Testing
Freshwater testing was conducted at the wetlands on the CCEHBR campus and lasted 35 days.
As in the saltwater phase of the verification test, the 6600 EDSs monitored the naturally
occurring target parameters 24 hours per day, while reference measurements were made and
turbidity and chlorophyll reference samples collected, again rotating among collection times.
Table 3-4 shows the sampling times and number of samples collected throughout the freshwater
phase. The 6600 EDSs were hung from a large post suspended several feet from the bottom of the
pond.
During this portion of the deployment, the salinity and stratification of the freshwater pond
increased. Natural weather and extreme tidal events caused the freshwater pond to become
brackish and highly stratified. Reference measurements taken at varying depths along the water
column during the first week of December showed significant stratification between the top and
bottom of the freshwater pond. As a result, the freshwater phase at the Hollings wetlands was
discontinued on December 8. The mesocosm deployment (Section 3.3.3) was extended to collect
data using a freshwater deployment.
Table 3-4. Schedule for Freshwater Sample Collection—Hollings Wetlands
Test Day Date # Reference Samples Activities
1 11/4/2003 Deploy 6600 EDSs
2 11/5/2003 6
3 11/6/2003 9
4 11/7/2003 6
17 11/20/2003 9
30 12/03/2003 9
35 12/08/2003 16 Retrieve 6600 EDSs
9
-------
3.3.3 Mesocosm Testing
Mesocosm testing was performed over 27 days according to the schedule shown in Table 3-5.
Reference measurements were made and water samples were collected during each test day
throughout the normal operating hours of the facility (nominally 6 a.m. to 6 p.m.). During this
phase, the mesocosm was manipulated to introduce variations in the measured parameters. The
turbidity of the system was varied by operating a pump near the sediment trays to suspend
additional solids in the water. Specific conductivity was varied by adding freshwater to the
saltwater during the last three weeks of testing. These activities are detailed in Table 3-5.
Table 3-5. Schedule for Mesocosm Sample Collection
Test Day Date # Reference Samples Activities
1 12/10/2003 4 Deploy 6600 EDSs in saltwater
3 12/12/2003 6 10:00 - Transition to freshwater (to change
specific conductivity)
4 12/13/2003 Begin freshwater portion of deployment
6 12/15/2003 4 11:05 - Turn off air bubblers and turn off
circulation pump
7 12/16/2003 4 10:40 - Turn on circulation pump
10:50 - Add mud slurry (to change turbidity)
13:00 - Add additional mud slurry
15:11 - Turn off circulation pump
8 12/17/2003 5
9 12/18/2003 2
24 1/2/2004 3 10:20 - Turn on air bubblers (to change DO)
27 1/5/2004 3 Retrieve 6600 ED Ss
Variations in DO, temperature, pH, and chlorophyll were driven by natural forces and the
changes in the other test parameters. Parameters over the ranges specified in Table 3-1 were
monitored by the 6600 EDS. Samples were collected and analyzed using a reference method for
comparison.
3.4 Reference Measurements
The reference measurements made in this verification test and the equipment used for the
measurements were as follows:
¦ DO—National Institute of Standards and Technology (NIST)-traceable, commercially
available probe (Orion 830A)
¦ Specific conductivity—NIST-traceable, handheld specific conductivity meter (Myron 4P)
10
-------
¦ Temperature—NIST-traceable, handheld thermocouple and readout (Orion 830A)
¦ pH—NIST-traceable, handheld pH meter (Orion 230)
¦ Turbidity—Hach Ratio XR turbidity meter (Hach 43900)
¦ Chlorophyll—Turner 10-AU fluorometer (total in vivo fluorescence).
Reagents were distilled deionized water (for field blanks) and a Hach Ratio XR turbidity standard
from Advanced Polymer Systems. Sampling equipment consisted of 0.5- to 1.0-L glass bottles, a
Niskin sampling device, and provisions for sample storage. The maximum sample holding times
are given in Table 3-6. All sample holding time requirements were met.
Table 3-6. Maximum Sample Holding Times
Parameter Holding Time
DO none(a)
Specific conductivity none
Temperature none
pH none
Turbidity 24 hours
Chlorophyll 1 week
{!i> "None" indicates that the sample analyses must be performed immediately after sample collection or in the water
column at the site.
11
-------
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(2) and the test/QA plan for this verification
test.(1)
4.1 Instrument Calibration
Both the portable and laboratory reference instruments were calibrated by CCEHBR according to
the procedures and schedules in place at the test facility, and documentation was provided to
Battelle.
4.2 Field Quality Control
Replicate samples were taken during field sampling for assessment of the reference methods. The
replicate samples were collected once each week during a regular sampling period by splitting
field samples into two separate samples (containers) and analyzing both by the same laboratory
reference methods. The results from the replicate analysis and the field blanks met the criteria
listed in Tables 4-1 and 4-2, respectively. A container of deionized water (field blank) was taken
to the field, brought back to the laboratory, and analyzed in the same manner as the collected
samples.
4.3 Sample Custody
Samples collected at the saltwater, freshwater, and mesocosm sites were transported by the
scientist performing the sampling at CCEHBR to the laboratory in an ice-filled cooler and
analyzed immediately; therefore, no chain-of-custody forms were required.
12
-------
Table 4-1. Replicate Analysis QC Criteria
Parameter Observed Agreement
DO ±5%
Specific conductivity ±5%
Temp erature ± 1 ° C
pH ±0.1
Turbidity ±5 NTU
Chlorophyll ±5%
Table 4-2. Expected Values for Field Blanks
Parameter
Observed Maximum Difference
Turbidity
1 NTU
Chlorophyll
3 x average of three blank filters
4.4 Audits
4.4.1 Performance Evaluation Audit
A performance evaluation (PE) audit was conducted by the Battelle Test Coordinator once during
the verification test to assess the quality of the reference measurements. For the PE audit,
independent standards were used. Table 4-3 shows the procedures used for the PE audit and
associated results.
Table 4-3. Summary of Performance Evaluation Audits
Audited
Parameter
Audit Procedure
Acceptable
Tolerance
Actual
Difference
Passed
Audit
DO
Oakton 100 monitor
±5%
1.1%
Yes
Specific
conductivity
Myron 4P meter
±5%
0.9%
Yes
Temperature
Orion 230 thermometer
±rc
0.0°C
Yes
pH
Oakton 300 pH meter
±0.1
0.05
Yes
Turbidity
Advanced Polymer Systems
turbidity standard
±10%
0.72%
Yes
Chlorophyll
Independent chlorophyll standard
±5%
0.4%
Yes
The DO measurement made by the Orion 830A was compared with that from a handheld DO
Oakton 100 monitor. Agreement within 1.1% was achieved. A handheld Oakton 300 specific
13
-------
conductivity meter was used to perform the specific conductivity audit. Agreement within 0.9%
between the results of the Myron 4P meter and those of the Oakton reference meter was seen. A
NIST-traceable Orion 230 thermometer was used for the temperature performance audit. The
comparison was made with a sample of collected water, and agreement was within 0.0°C. The
Oakton 100 handheld pH reference meter was compared with the Oakton 300 handheld pH
meter. A pH tolerance of 0.05 was recorded. The Hach turbidity meter measurements were
compared with an independent turbidity standard. Agreement within 0.4% was observed. The in
vivo chlorophyll measurements agreed within 0.1%.
4.4.2 Technical Systems Audit
The Battelle Quality Manager conducted a technical systems audit (TSA) on October 28, 2003, to
ensure that the verification test was performed in accordance with the test/QA plan(1) and the
AMS Center QMP.(2) As part of the audit, the Battelle Quality Manager reviewed the reference
methods 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. The
records concerning the TSA are permanently stored with the Battelle Quality Manager.
During the verification test, two deviations from the test/QA plan were necessary. The first
occurred when natural weather events caused the freshwater pond to become brackish and highly
stratified, resulting in reference measurements that were not representative of the water the
6600 EDS measured. An extended freshwater period, beginning on December 13, 2003, was
added to the end of mesocosm deployment to provide data from a freshwater deployment.
Therefore, relative bias and linearity data were not collected at the freshwater site. The data were
collected from the mesocosm extension instead. The second deviation occurred when a problem
with the Niskin sampler developed. The sampler broke after several uses at the beginning of the
saltwater period and was replaced as soon as possible. However, this malfunction resulted in
fewer reference samples. The deviations had no impact on the results of the test.
4.4.3 Audit of Data Quality
At least 10%) of the data acquired during the verification test was 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.
4.5 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.(2) Once the assessment report was prepared, the 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 TSA were sent to the EPA.
14
-------
4.6 Data Review
Records generated in the verification test were reviewed within two weeks of generation 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 Battelle and a CCEHBR 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.
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
events
CCEHBR
Laboratory record
books/data sheets
Start/end of test; at
each change of a test
parameter; at sample
collection
Used to organize/check
test results; manually
incorporated data into
spreadsheets - stored in
test binder
Test parameters
Battelle/
CCEHBR
Laboratory record
books/data sheets
Each sample
collection
Used to organize/check
test results; manually
incorporated data into
spreadsheets - stored in
test binder
6600 EDS data
- digital display
- electronic
output
CCEHBR
CCEHBR
Data sheets
Probe data
acquisition system
(DAS); data
stored on probe
downloaded to
personal computer
Continuous
15-minute sampling;
data downloaded to
personal computer
Used to organize/check
test results; incorporated
data into electronic
spreadsheets - stored in
test binder
Reference monitor
readings/reference
analytical results
CCEHBR
Laboratory record
book/data sheets
or data manage-
ment system, as
appropriate
After each batch
sample collection;
data recorded after
reference method
performed
Used to organize/check
test results; manually
incorporated data into
spreadsheets - stored in
test binder
Reference calibration
data
CCEHBR
Laboratory record
books/data
sheets/DAS
Whenever zero and
calibration checks are
done
Documented correct
performance of reference
methods - stored in test
binder
PE audit results
Battelle
Laboratory record
books/data
sheets/DAS
At times of PE audits
Test reference methods
with independent
standards/measurements -
stored in test binder
(a) All activities subsequent to data recording were carried out by Battelle.
15
-------
Chapter 5
Statistical Methods
The statistical methods presented in this chapter were used to verify the performance parameters
listed in Section 3.1.
5.1 Calibration Check Accuracy
The 6600 EDS was calibrated for each measured parameter at the beginning and end of each
deployment period according to the vendor's instruction manual. The results from the calibration
checks were summarized, and accuracy was determined each time the calibration check was
conducted. Calibration check accuracy (A) is reported as a percentage, calculated using the
following equation:
A=l-(C-Cp)/Csx 100 (1)
where Cs is the value of the reference standard, and Cp is the value measured by the 6600 EDS.
The closer^ is to 100, the more consistent the calibration check accuracy.
5.2 Relative Bias
Water samples were analyzed by both the reference method and the 6600 EDS, and the results
were compared. The results for each sample were recorded, and the accuracy was expressed in
terms of the average relative bias (B), as calculated from the following equation:
CR - CP
B= x 100 (2)
^R
where CP is a measurement taken from the 6600 EDS being verified at the same time as the
reference measurement was taken, and CR is the reference measurement. This calculation was
performed for each reference sample analysis for each of the six target water parameters. In
addition, relative bias was assessed independently for each 6600 EDS so the results may be used
to determine inter-unit reproducibility.
16
-------
5.3 Precision
The standard deviation (S) of the measurements made during a period of stable operation at the
mesocosm was calculated and used as a measure of probe precision:
where n is the number of replicate measurements, Ck is the concentration reported for the kth
measurement, and C is the average concentration of the replicate measurements.
Precision was calculated for each of the six target water parameters. Probe precision was reported
in terms of the percent RSD of the series of measurements.
5.4 Linearity
For target water parameters, linearity was assessed by linear regression, with the analyte
concentration measured by the reference method as an independent variable and the reading from
the analyzer verified as a dependent variable. Linearity is expressed in terms of the slope,
intercept, and coefficient of determination (r2). Linearity was assessed separately for each 6600
EDS.
5.5 Inter-Unit Reproducibility
The results obtained from the two 6600 EDSs were compiled independently and compared to
assess inter-unit reproducibility. Inter-unit reproducibility was determined by calculating the
average absolute difference between the two 6600 EDSs. In addition, the two 6600 EDSs were
compared by evaluating the relative bias of each.
¦5= —I" (Ck-C)
n_1L^k=I^ *
1/2
(3)
S
%RSD = = x 100
C
(4)
17
-------
Chapter 6
Test Results
The results of the verification of the two 6600 EDSs (identified as YSIAA and YSIAB in this
report) are presented in this section. The 6600 EDS data were recorded at 15-minute intervals
throughout the verification test. First, a visual record of the condition of the 6600 EDSs pre- and
post-deployment is discussed, then the statistical comparisons are made. Finally, a record of the
activities involved in servicing and maintenance of the 6600 EDSs is presented.
Prior to the initial saltwater deployment, the 6600 EDSs were in "like-new" condition. That is,
they arrived from the vendor crated and ready for installation. Figure 6-1 shows one of the two
Figure 6-1. 6600 EDS Prior to Deployment. Starting in the
upper right and proceeding clockwise: (1) clean 6600 EDS,
(2) close-up of clean probes, (3) close-up of wiping brushes,
(4) protective shroud and mesh, (5) aluminum tube guarding
against crushing damage.
18
-------
6600 EDSs in its pre-deployment condition. As deployed, the end where the individual probes
connect is protected by the PVC shroud shown in Figure 6-1. Over this shroud is a nylon mesh
that was used to keep small animals away from the optical sensors of the 6600 EDS. Finally, this
entire apparatus was placed inside an aluminum tube that guarded against crushing damage.
Following the saltwater deployment, the 6600 EDSs were retrieved from the water and imme-
diately returned to the laboratory to record the post-deployment condition. Figure 6-2 shows the
post-deployment condition of the 6600 EDSs. The 6600 EDSs were covered with a combination
of green algae, silt, and some shell growth. The protective screens appeared to have helped keep
some of this materi al off of the sensor heads.
Figure 6-2. 6600 EDS After Saltwater Deployment. 6600 EDSs
on the pier (top), close-up of wiping brushes (bottom)
Prior to redeployment at the freshwater location, the 6600 EDSs were cleaned and serviced as
necessary. Then the 6600 EDSs were placed overnight in a tank of oxygen-saturated water before
deployment. Figure 6-3 shows the cleaned and reconditioned 6600 EDSs in this tank.
19
-------
Figure 6-3. Cleaned and Reconditioned 6600 EDSs in Storage
Tank Used Between Deployments
Finally, the condition of the 6600 EDSs after the freshwater deployment was recorded and is
shown in Figure 6-4.
Figure 6-4. 6600 EDS After Freshwater
Deployment
20
-------
6.1 Calibration Check Accuracy
The 6600 EDSs were calibrated at the beginning of each deployment period, and the calibrations
were checked at the end of each deployment. In the case of pH and turbidity, a two-point
calibration was performed as instructed by the vendor. No check was performed for temperature.
The calibration check levels were selected based on the manufacturer's instructions. Table 6-1
shows the results from these calibration checks for the saltwater, freshwater, and mesocosm tests.
The "Calibration Standard" column refers to the listed concentration of the standards used in the
calibrations, the "YSIAA and YSIAB Readings" columns give the 6600 EDSs results during the
calibration checks, and the "YSI AA and YSI AB Accuracy" columns show the calibration check
accuracy using the calculations given in Section 5.1. In the cases where the zero point was
checked, only the absolute difference is listed. During the deployments, the accuracy for DO
ranged from 87.0 to 105%; for specific conductivity, from 96.8 to 102%; for pH, from 98.3 to
102%; and for turbidity, from 98 to 101%, The zero point check for turbidity resulted in a
difference of -0.2 to 0.3 NTU; and, for chlorophyll, the zero point check resulted in a difference
of -0.5 to 0.9 total (in vivo) chlorophyll.
The two extreme points were found during the DO calibration checks on December 9, 2003, of
87%) (YSI AA) and 105% (YSI AB) after the freshwater deployment. It was observed that the
6600 EDS had several bubbles under the membrane. These bubbles could have been formed
during transit and may have decreased calibration check accuracy. These bubbles were not
present during other calibration checks.
6.2 Relative Bias
Relative bias (the percent difference between the 6600 EDS measurements and the reference
measurements) was assessed by comparing the reference measurements with the YSI AA and
YSI AB readings. The 6600 EDS reading that was closest in time to the reference sample was
used. Plots of the YSI AA and YSI AB data, along with the corresponding reference measure-
ments that were used for the relative bias calculations, are shown in Figures 6-5a through 1.
The relative bias results are summarized in Table 6-2. As mentioned in Section 3.3.2, due to the
stratification of the freshwater pond, no relative bias calculations were conducted on measure-
ments between November 11 and December 8, 2003. In general, the relative bias was less for
temperature, specific conductivity, DO, and pH; while the optically measured parameters of
chlorophyll and turbidity were much greater. This may be due to the fact that the 6600 EDS
measurements for turbidity and chlorophyll are instantaneous, while the reference measurements
are integrated over several seconds.
Specifically, the results from the temperature measurements yielded the smallest relative bias,
being less than 1% over the test. Dissolved oxygen and pH were less than 1.7% during the
mesocosm deployment and less than 8.1% during the saltwater deployment. Specific conductivity
was less than 12.8% during the mesocosm deployment and less than 8.7% during the saltwater
deployment. During the saltwater deployment, the 6600 EDS specific conductivity measurements
21
-------
Table 6-1. Calibration Check Accuracy
Calibration Standard
YSIAA Readings
Specific
Specific
Deployment
DO
conductivity
Turbidity
Chlorophyll
DO
conductivity
Turbidity
Chlorophyll
Location
Date
(%)
(mS/cm)
PH
(NTU)
(Total)
(%)
(mS/cm)
PH
(NTU)
(Total)
Saltwater
10/29/2003
100
50.0
7.00
0.0
0.0
99.6
50.1
7.02
0.3
-0.5
10/29/2003
10.0
120
10.1
120
Freshwater
12/9/2003
100
1.0
7.00
0.0
0.0
87.0
1.01
6.88
-0.2
0.9
12/9/2003
10.0
120
10.1
120
Mesocosm
1/13/2004
100
1.0
7.00
0.0
0.0
97.0
0.968
7.12
0.20
0.8
1/13/2004
10.0
120
10.1
120
-------
Table 6-1. Calibration Check Accuracy (continued)
Calibraton Standard
YSIAB Readings
Deployment
Specific
Specific
Location
DO
conductivity
Turbidity
Chlorophyll
DO
conductivity
Turbidity
Chlorophyll
Date
(%)
(mS/cm)
PH
(NTU)
(Total)
(%)
(mS/cm)
PH
(NTU)
(Total)
Saltwater
10/29/2003
100
50.0
7.00
0.0
0.0
101
49.7
7.12
0.2
-0.3
10/29/2003
10.0
120
10.1
120
Freshwater
12/9/2003
100
1.00
7.00
0.0
0.0
105
1.02
7.01
-0.2
-0.1
12/9/2003
10.0
120
10.1
123
Mesocosm
1/13/2004
100
1.00
7.00
0.0
0.0
99.1
0.98
7.06
0.2
-0.1
1/13/2004
10.0
120
10.02
124
-------
Table 6-1. Calibration Check Accuracy (continued)
YSIAA Calibration Check Accuracy (%)
YSI AB Calibration Check Accuracy (%)
Deployment
Specific
Specific
Location
Date
DO
conductivity
PH
Turbidity
Chlorophyll
DO
conductivity
PH
Turbidity
Chlorophyll
Saltwater
10/29/2003
99.6
100
100
0.3(a)
-0.5®
101
99.5
102
0.2(a)
-0.3(b)
10/29/2003
101
100
101
98
Freshwater
12/9/2003
87.0
101
98.3
-0.2(a)
0.9(b)
105
102
100
-0.2(a)
-0.1(b)
12/9/2003
101
99
101
100
Mesocosm
1/13/2004
97.0
96.8
102
0.2(a)
0.8(b)
99.1
98.1
101
0.2(a)
-0.1(b)
1/13/2004
101
99
100
101
^ Because zero point was checked, only absolute difference in NTU is listed.
^ Because zero point was checked, only absolute difference in total (in vivo) chlorophyll is listed.
-------
A s
ft A
a
s
Saltwater
10/6/2003 12:00AM 10/11/2003 12:00 AM 10/16/2003 12:00AM 10/21/2003 12:00AM 10/26/2003 12:00 AM 10/31/2003 12:00 AM
Date and Time
Figure 6-5a. Relative Bias Data for DO (Saltwater)
E, 10
o
~ Reference
0 AA
AAB
&
t
Mesocosm
12/10/2003 0:00
12/15/2003 0:00
12/20/2003 0:00
12/25/2003 0:00
Date and Time
12/30/2003 0:00
1/4/2004 0:00
1/9/2004 0:00
Figure 6-5b. Relative Bias Data for DO (Mesocosm)
25
-------
£
s
o 20
O
~ Reference
0AA
AAB
i 8
t :
Saltwater
i_L
10/6/2003 12:00 AM 10/11/2003 12:00 AM 10/16/2003 12:00 AM 10/21/2003 12:00 AM 10/26/2003 12:00 AM 10/31/2003 12:00 AM
Date and Time
Figure 6-5c. Relative Bias Data for Specific Conductivity (Saltwater)
5) 20
E
~ Reference
0AA
A AB
t #
Mesocosm
12/10/2003 0:00 12/15/2003 0:00 12/20/2003 0:00 12/25/2003 0:00 12/30/2003 0:00 1/4/2004 0:00 1/9/2004 0:00
Date and Time
Figure 6-5d. Relative Bias Data for Specific Conductivity (Mesocosm)
26
-------
30
~ Reference
0AA
AAB
Saltwater
10/6/2003 12:00 AM 10/11/2003 12:00 AM 10/16/2003 12:00 AM 10/21/2003 12:00 AM 10/26/2003 12:00 AM 10/31/2003 12:00 AM
Date and Time
Figure 6-5e. Relative Bias Data for Temperature (Saltwater)
t
a
~
~ Reference
~ AA
AAB
Mesocosm
12/10/2003 0:00 12/15/2003 0:00 12/20/2003 0:00
12/25/2003 0:00
Date and Time
12/30/2003 0:00 1 /4/2004 0:00
Figure 6-5f. Relative Bias Data for Temperature (Mesocosm)
27
-------
B B
~ Reference
~ AA
A AB
6 9
B ~
Saltwater
10/6/2003 12:00 AM 10/11/2003 12:00 AM 10/16/2003 12:00 AM 10/21/2003 12:00 AM 10/26/2003 12:00 AM 10/31/2003 12:00 AM
Date and Time
Figure 6-5g. Relative Bias Data for pH (Saltwater)
? ? f 9
~ Reference
BAA
A AB
Mesocosm
12/10/2003 0:00 12/15/2003 0:00 12/20/2003 0:00 12/25/2003 0:00 12/30/2003 0:00
Date and Time
1/4/2004 0:00 1/9/2004 0:00
Figure 6-5h. Relative Bias Data for pH (Mesocosm)
28
-------
~ Reference
0 AA
AAB
Saltwater
J % •
10/6/2003 12:00 AM 10/11/2003 12:00 AM 10/16/2003 12:00 AM 10/21/2003 12:00 AM 10/26/2003 12:00 AM 10/31/2003 12:00 AM
Date and Time
Figure 6-5i. Relative Bias Data for Turbidity (Saltwater)
~ Reference
0AA
AAB
A 6
Mesocosm
t
0 -
12/10/21)03 0:00 12/15/2003 0:00 12/20/2003 0:00 12/25/2003 0:00 12/30/2003 0:00 1/4/2004 0:00 1/9/2044 0:00
Date and Time
Figure 6-5j. Relative Bias Data for Turbidity (Mesocosm)
29
-------
~ Reference
0AA
AAB
~ ~
0
$
6
Saltwater
a &
-j*
n ft
~ 0
10/6/2003 12:00 AM 10/11/2003 12:00 AM 10/16/2003 12:00 AM 10/21/2003 12:00 AM 10/26/2003 12:00 AM 10/31/2003 12:00 AM
Date and Time
Figure 6-5k. Relative Bias Data for Chlorophyll (Saltwater)
~ Reference
~ AA
AAB
4 l 1 «
a 4 7
ft It
103 0:00 12/15/2003 0:00 12/20/2003 0:00 12/25/2003 0:00 12/30/2003 0:00 1/4/2004 0:00
Mesocosm
1/9/2004 0:00
Date and Time
Figure 6-51. Relative Bias Data for Chlorophyll (Mesocosm)
30
-------
Table 6-2. Average Relative Bias Results for YSIAA and YSIAB
Saltwater
Mesocosm
Parameter
% Rel. Bias AA
% Rel. Bias AB
% Rel. Bias AA
% Rel. Bias AB
DO
-7.4
-5.7
0.3
1.7
Specific conductivity
-8.7
-7.6
12.8
10.2
Temperature
-0.1
-0.1
-0.2
-0.2
pH
7.5
8.1
0.39
0.35
Turbidity
-33.6
-184
-17.4
-30.1
Chlorophyll
-98.0
-133
-72.1
-131
-------
displayed a positive 3 to 4 mS/cm relative to reference measurements. This shift was not present
during the mesocosm deployment. Chlorophyll and turbidity ranged between -17.4% and -184%.
Another representation of the 6600 EDS performance may be obtained by referring to the
comparison of reference and 6600 EDS measurements for pre-and post-calibration results
(Section 6.1), where the 6600 EDS displayed closer agreement to the reference standards.
6.3 Precision
Table 6-3 shows the results of calculations taken from measurements performed before the
saltwater deployment. The precision, reported as %RSD, was less than 1% for DO, specific
conductivity, temperature, and pH. Data from turbidity and chlorophyll resulted in higher
%RSDs (19.4 and 29.6 for turbidity and 19.8 and 24.6 for chlorophyll). In the test procedures
employed to determine precision, turbidity and chlorophyll were subject to possible spikes when
a particle passed the field of view of the sensor head.
32
-------
Table 6-3. Measurements and Percent Relative Standard Deviations for YSIAA and YSIAB During Stable Mesocosm
Operation
YSI AA
YSI AB
Specific
Specific
DO
Conductivity Temperature
Turbidity Chlorophyll
DO
Conductivity
Temperature
Turbidity
Chlorophyll
(mg/L)
(mS/cm)
(°C)
pH
(NTU)
(Total)
(mg/L)
(mS/cm)
(°C)
pH
(NTU)
(Total)
Maximum
7.38
44.0
20.7
7.35
2.00
2.20
7.79
43.8
20.7
7.46
2.10
2.70
Minimum
7.26
43.8
20.2
7.22
0.5
1.0
7.65
42.9
20.2
7.24
1.0
0.60
Standard
Deviation
0.03
0.06
0.15
0.05
0.38
0.30
0.04
0.23
0.15
0.06
0.30
0.38
Average
7.32
43.9
20.4
7.27
1.29
1.49
7.72
43.3
20.5
7.33
1.52
1.55
%RSD
0.44
0.14
0.74
0.62
29.6
19.8
0.46
0.53
0.75
0.76
19.4
24.6
-------
6.4 Linearity
Linearity was assessed by comparing probe readings against the reference values for each of the
parameters at each deployment location. Figures 6-6a-l give the results of this comparison by
showing the slope, intercept, and coefficient of determination (r2) for each parameter. In general,
linearity and regression coefficients indicated better agreement between the 6600 EDS readings
and reference values for the parameters that do not use optical measurements, such as DO,
specific conductivity, temperature, and pH. This may be because the test site water was dynamic
and the measurements taken were instantaneous. In such cases, the reference method and the
6600 EDS were not measuring exactly the same water sample. The manifestation of this effect
would be largest whenever the parameters being measured were rapidly changing, such as in the
case of chlorophyll, turbidity, and the induced dynamic environment found in the mesocosm.
34
-------
Reference DO (mg/L)
Figure 6-6a. Linearity Data for DO (Saltwater)
Reference DO (mg/L)
Figure 6-6b. Linearity Data for DO (Mesocosm)
35
-------
Reference Conductvity (mS/cm)
Figure 6-6c. Linearity Data for Specific Conductivity (Saltwater)
Reference Conductvity (mS/cm)
Figure 6-6d. Linearity Data for Specific Conductivity (Mesocosm)
36
-------
Reference Temperature (C)
Figure 6-6e. Linearity Data for Temperature (Saltwater)
Reference Temperature (C)
Figure 6-6f. Linearity Data for Temperature (Mesocosm)
37
-------
Reference pH
Figure 6-6g. Linearity Data for pH (Saltwater)
Reference pH
Figure 6-6h. Linearity Data for pH (Mesocosm)
38
-------
~ AA
A AB
- - - AB
AA Linear Regression
y = 1.3358X + 0.0199
r2 = 0.7696
AB Linear Regression
y = -0.6713x +60.888
r2 = 0.0039
15 20 25 30
Reference Turbidity (NTU)
Figure 6-6i. Linearity Data for Turbidity (Saltwater)
AA
AB
—AA
- AB
AA Linear Regression
y = 1.0396X +0.1739
r2 = 0.7768
AB Linear Regression
y = 1.023X +0.4312
r2 = 0.7511
Reference Turbidity (NTU)
Figure 6-6j. Linearity Data for Turbidity (Mesocosm)
39
-------
Reference Chlorophyll (Total)
Figure 6-6k. Linearity Data for Chlorophyll (Saltwater)
Figure 6-61. Linearity Data for Chlorophyll (Mesocosm)
40
-------
6.5 Inter-Unit Reproducibility
Inter-unit reproducibility was assessed both by comparing the relative bias of the two 6600 EDSs
(Section 6.2) and by comparing the average differences between the two 6600 EDS readings for
each parameter at each deployment location. Freshwater results are included because the two
6600 EDSs were deployed to the same depth. The assessment using the relative bias data is done
by looking at the relative bias results in Table 6-2 and comparing the percent relative bias for AA
and AB. That comparison, in general, does not show a difference in the relative bias between YSI
AA and AB.
This section presents all the 6600 EDS data collected during the deployments for both AA and
AB. A comparison of the average absolute differences between the two 6600 EDS readings for
each parameter at each deployment location is used to indicate inter-unit reproducibility.
Figures 6-7 through 6-12 show the data used for these calculations. Note that Figure 6-1 la is on a
log scale, since the range of turbidity results was unusually broad. The results of average
difference comparisons are shown in Table 6-4, where "n" is the number of measurements.
In most cases, the absolute difference between YSI AA and AB was less in the mesocosm phase
than in the saltwater or freshwater phase. The DO difference between the two 6600 EDSs tested
averaged 0.28 mg/L (Figures 6-7a-c) across all three test phases. The difference in specific
conductivity 0.28 mS/cm (Figures 6-8a-c). The average difference in temperature readings was
0.02°C (Figures 6-9a-c). The average difference in pH readings was 0.04 (Figures 6-10a-c). The
average difference in turbidity readings was 3.67 NTU, (Figures 6-lla-c). Finally, chlorophyll
readings had an average difference of 1.07 (Figures 6-12a-c).
See Table 2-1 for vendor's specifications and Table 4-1 for quality control criteria and tolerances
associated with the reference monitors.
41
-------
Table 6-4. Average Absolute Difference Between YSIAA and YSIAB Readings for Each Parameter at Each
Deployment Location
Average Absolute Difference Between YSI AA and YSI AB
Specific
DO Conductivity Temperature Turbidity Chlorophyll
Location
(n)
(mg/L)
(mS/cm)
(°C)
PH
(NTU)
(total)
Saltwater
2,802
0.14
0.42
0.03
0.01
10.5
0.78
Freshwater
2,800
0.48
0.38
0.02
0.08
0.29
1.95
Mesocosm
2,588
0.19
0.05
0.02
0.03
0.27
0.48
Average
0.28
0.28
0.02
0.04
3.67
1.07
-------
0
Saltwater
9/26/2003 10/1/2003 10/6/2003 10/11/2003 10/16/2003 10/21/2003 10/26/2003 10/31/2003 11/5/2003
12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM
Date and Time
Figure 6-7a. Inter-Unit Reproducibility Data for DO During Saltwater Tests
-------
10/26/2003 10/31/2003 11/5/2003 11/10/2003 11/15/2003 11/20/2003 11/25/2003 11/30/2003 12/5/2003 12/10/2003 12/15/2003
12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM
Date and Time
Figure 6-7b. Inter-Unit Reproducibility Data for DO During Freshwater Tests
-------
11.5
10.5 -
AA
AB
~ Reference
Mesocosm
12/5/2003 12:00 12/10/2003 12:00 12/15/2003 12:00 12/20/2003 12:00 12/25/2003 12:00 12/30/2003 12:00 1/4/2004 12:00 1/9/2004 12:00
AM AM AM AM AM AM AM AM
Date and Time
Figure 6-7c. Inter-Unit Reproducibility Data for DO During Mesocosm Tests
-------
Saltwater
17
9/26/2003 10/1/2003 10/6/2003 10/11/2003 10/16/2003 10/21/2003 10/26/2003 10/31/2003 11/5/2003
12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM
Date and Time
Figure 6-8a. Inter-Unit Reproducibility Data for Specific Conductivity During Saltwater Tests
-------
45
10
10/26/2003 10/31/2003 11/5/2003 11/10/2003 11/15/2003 11/20/2003 11/25/2003 11/30/2003 12/5/2003
12:00AM 12:00AM 12:00AM 12:00AM 12:00AM 12:00AM 12:00AM 12:00AM 12:00AM
Date and Time
12/10/2003 12/15/2003
12:00AM 12:00AM
Figure 6-8b. Inter-Unit Reproducibility Data for Specific Conductivity During Freshwater Tests
-------
AA
AB
~ Reference
1
~
<
~
<
~
-
Mesocosm
f —,
12/5/2003 12:00 12/10/2003 12:00 12/15/2003 12:00 12/20/2003 12:00 12/25/2003 12:00 12/30/2003 12:00 1/4/2004 12:00 1/9/2004 12:00
AM AM AM AM AM AM AM AM
Date and Time
Figure 6-8c. Inter-Unit Reproducibility Data for Specific Conductivity During Mesocosm Tests
-------
Date and Time
Figure 6-9a. Inter-Unit Reproducibility Data for Temperature During Saltwater Tests
-------
12
Freshwater
10
10/26/2003 10/31/2003 11/5/2003 11/10/2003 11/15/2003 11/20/2003 11/25/2003 11/30/2003 12/5/2003 12/10/2003 12/15/2003
12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM
Date and Time
Figure 6-9b. Inter-Unit Reproducibility Data for Temperature During Freshwater Tests
-------
o
ai
ns
ai
a.
E
12/5/2003 12:00
AM
12/10/2003 12:00
AM
12/15/2003 12:00
AM
12/20/2003 12:00 12/25/2003 12:00
AM AM
Date and Time
12/30/2003 12:00
AM
1/4/2004 12:00
AM
1/9/2004 12:00
AM
Figure 6-9c. Inter-Unit Reproducibility Data for Temperature During Mesocosm Tests
-------
9/26/2003 10/1/2003 10/6/2003 10/11/2003 10/16/2003 10/21/2003 10/26/2003 10/31/2003 11/5/2003
12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM
Date and Time
AA
AB
~ Reference
Figure 6-10a. Inter-Unit Reproducibility Data for pH During Saltwater Tests
-------
AA
AB
. ....
—
Freshwater
10/26/2003 10/31/2003 11/5/2003 11/10/2003 11/15/2003 11/20/2003 11/25/2003 11/30/2003 12/5/2003 12/10/2003 12/15/2003
12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM
Date and Time
Figure 6-10b. Inter-Unit Reproducibility Data for pH During Freshwater Tests
(on 10/31 and 11/5 YSIAA and AB drop to a pH of zero when removed from water)
-------
14
12
AA
AB
~ Reference
10
~
~
"CT
Mesocosm
12/5/2003 12:00
AM
12/10/2003 12:00
AM
12/15/2003 12:00
AM
12/20/2003 12:00
AM
12/25/2003 12:00
AM
12/30/2003 12:00
AM
1/4/2004 12:00
AM
1/9/2004 12:00
AM
Date and Time
Figure 6-10c. Inter-Unit Reproducibility Data for pH During Mesocosm Tests
-------
10000 -|
AA
AB
~ Reference
9/26/2003 10/1/2003 10/6/2003 10/11/2003 10/16/2003 10/21/2003 10/26/2003 10/31/2003 11/5/2003
12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM
Date and Time
Figure 6-lla. Inter-Unit Reproducibility Data for Turbidity During Saltwater Tests (log scale)
-------
Figure 6-llb. Inter-Unit Reproducibility Data for Turbidity During Freshwater Tests
-------
Figure 6-1 lc. Inter-Unit Reproducibility Data for Turbidity During Mesocosm Tests
-------
9/26/2003 10/1/2003 10/6/2003 10/11/2003 10/16/2003 10/21/2003 10/26/2003 10/31/2003 11/5/2003
12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM 12:00 AM
Date and Time
Figure 6-12a. Inter-Unit Reproducibility Data for Total Chlorophyll During Saltwater Tests
-------
Figure 6-12b. Inter-Unit Reproducibility Data for Total Chlorophyll During Freshwater Tests
-------
6
Figure 6-12c. Inter-Unit Reproducibility Data for Total Chlorophyll During Mesocosm Tests
-------
6.6 Other Factors
6.6.1 Ease of Use
The 6600 EDSs were installed and deployed by CCEHBR staff with the oversight of YSI during
installation and Battelle during deployment. The only maintenance required was periodically
changing the DO membrane and recalibrating the measured parameters at the end of the
deployment periods. Data were collected from the 6600 EDS to a personal computer using a
vendor-supplied serial connection cable and YSI software, Ecowatch version 3.15.00. A sample
printout of the data is shown in Appendix A. The software provided simple access to the data for
downloading and viewing. The 6600 EDSs required minimal interaction by operators during the
test. Those interactions that did occur are described in Table 6-5.
Table 6-5. Installation, Operation, and Maintenance Activities
Date
Service Time
Activity
10/1/2003
10/2/2003
10/30/2003
10/31/2003
11/4/2003
12/8/2003
12/10/2003
1/5/2004
1/5/2004
Total
180 minutes
180 minutes
15 minutes
375 minutes
Vendor representatives arrived on site.
6600 EDS deployed.
6600 EDS collected.
Data downloaded; oxygen membrane changed;
6600 EDS cleaned and calibrated.
6600 EDS deployed.
6600 EDS collected; data downloaded; oxygen
membrane changed; 6600 EDS cleaned and
calibrated.
6600 EDS deployed.
6600 EDS collected; data downloaded.
End of test.
6.6.2 Data Completeness
All of the required data were recorded during this verification. The two 6600 EDSs submitted for
this test collected data at 15-minute intervals from October 1, 2003, until January 5, 2004,
without any interruption in data collection. One hundred percent of the required data was
collected by the 6600 EDS.
61
-------
Chapter 7
Performance Summary
Two 6600 EDSs were evaluated in saltwater, freshwater, and mesocosm environments between
October 2, 2003, and January 5, 2004. These 6600 EDSs measured DO, specific conductivity,
temperature, pH, turbidity, and chlorophyll in water at 15-minute intervals throughout these
deployments. Table 7-1 summarizes the performance of the 6600 EDSs.
Table 7-1. Summary of Performance
Statistical
YSI AA
YSI AB
Measure
Parameter
Saltwater
F reshwater
Mesocosm
Saltwater
F reshwater
Mesocosm
DO (%)
99.6
87.0
97.0
101
105
99.1
Calibration check
Specific conductivity (%)
pH (%)
100
100-101
101
98.3-101
96.8
102-101
99.5
101-102
102
100-101
98.1
100-101
accuracy ^
Turbidity at 120 NTU (%)
Turbidity at 0 NTU (NTU)
100
0.3
99
-0.2
99
0.2
98
0.2
100
-0.2
101
0.2
Chlorophyll (total in vivo)
-0.5
0.9
0.8
-0.3
-0.1
-0.1
DO (%)
-7.4
_(°)
0.3
-5.7
_(°)
1.7
Average relative
bias ®
Specific conductivity (%)
Temperature (%)
pH (%)
-8.7
-0.1
7.5
_(°)
_(°)
_(°)
12.8
-0.2
0.39
-7.6
-0.1
8.1
_(°)
_(°)
_(°)
10.2
-0.2
0.35
Turbidity (%)
Chlorophyll (%)
-33.6
-98.0
_(°)
_(°)
-17.4
-72.1
-184
-133
_(°)
_(°)
-30.1
-131
YSI AA
YSI AB
DO (%RSD)
0.44
0.46
Specific conductivity
(%RSD)
0.14
0.53
Average precision
Temperature (%RSD)
pH (%RSD)
Turbidity (%RSD)
Chlorophyll (%RSD)
0.74
0.62
29.6
19.8
0.75
0.76
19.4
24.6
Linearity
Linearity and regression coefficients indicated better agreement between the
6600 EDS readings and reference values for the parameters that do not use
optical measurements, such as DO, specific conductivity, temperature, and pH.
Average Difference Between YSIAA and AB Readings
Saltwater
F reshwater
Mesocosm
Inter-unit
reproducibility
DO (mg/L)
Specific conductivity
(mS/cm)
Temperature (°C)
PH
Turbidity (NTU)
Chlorophyll (total)
0.14
0.42
0.03
0.01
10.5
0.78
0.48
0.38
0.02
0.08
0.29
1.95
0.19
0.05
0.02
0.03
0.27
0.48
(A)
The closer the percentage is to 100, the better.
® The closer the percentage is to zero, the better.
(c:i Stratification; no data reported.
62
-------
Chapter 8
References
Test/QA Plan for Long-Term Deployment of Multi-Parameter Water Quality
Probe s/Sondes, Battelle, Columbus, Ohio, Version 1.0, May 2002.
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.
63
-------
Appendix A
Reference Sample and Probe Readings
A-l
-------
SW738AB.DAT
30.0*
27.0-
24.0-
| 21.0-
H 18,0-
15.0+
07:16
11-Ot
53.0-
41.4-
> 29-8'
5 18.2-
07:16
6,10"i
;aa/\aMAaAaAaAaAMAaawaa/ww^a«jw\aAaAaA7WWWWW\a/
16.04-
5.02-
10/12/03 10/18/03
DateTime(M/D/Y)
A-2
------- |