United States
Environmental Protection
Agency
Persistence of Toxic Industrial
Chemical Warfare Agents on
Building Materials Under
Conventional Environmental
Conditions
INVESTIGATION REPORT
National Homeland Security Research Cente
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II
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EPA/600/R-08/075 July 2008 www.epa.gov/ord
Persistence of Toxic Industrial Chemicals
and Chemical Warfare Agents on
Building Materials Under Conventional
Environmental Conditions
INVESTIGATION REPORT
Ian C. MacGregor
James V. Rogers
Donald V. Kenny
Timothy Hayes
Michael L. Taylor
Marcia G. Nishioka
Karen B.Riggs
Zachary J. Willenberg
Robert T. Krile
Harry J. Stone
Battelle
505 King Avenue
Columbus, OH 43201
Shawn Ryan
Task Order Project Officer
National Homeland Security Research Center
Office of Research and Development
U.S. Environmental Protection Agency
Mail Code E343-06
Research Triangle Park, NC 27711
Office of Research and Development
National Homeland Security Research Center, Decontamination and Consequence Management Division
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Disclaimer
The U.S. Environmental Protection Agency (EPA), through its Office of Research
and Development's National Homeland Security Research Center (NHSRC). funded
and managed this investigation through a Blanket Purchase Agreement under General
Services Administration contract number GS23F0011L-3 withBattelle. This report
has been peer and administratively reviewed and has been approved for publication as
an EPA document. It does not necessarily reflect the views of the Agency. No official
endorsement should be inferred. EPA does not endorse the purchase or sale of any
commercial products or services.
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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 (ORD)
provides data and science support that can be used to solve environmental problems and
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.
In September 2002, EPA announced the formation of the National Homeland Security
Research Center (NHSRC). NHSRC is part of the ORD; it manages, coordinates,
supports, and conducts a variety of research and technical assistance efforts. These efforts
are designed to provide appropriate, affordable, effective, and validated technologies and
methods for addressing risks posed by chemical, biological, and radiological terrorist
attacks. Research focuses on enhancing our ability to detect, contain, and decontaminate
in the event of such attacks.
NHSRC's team of world renowned scientists and engineers is dedicated to understanding
the terrorist threat, communicating the risks, and mitigating the results of attacks. Guided
by the roadmap set forth in EPA's Strategic Plan for Homeland Security, NHSRC ensures
rapid production and distribution of security-related products.
The NHSRC has created the Technology Testing and Evaluation Program (TTEP)
in an effort to provide reliable information regarding the performance of homeland
security related technologies. TTEP provides independent, quality-assured performance
information that is useful to decision makers in purchasing or applying the tested
technologies. It provides potential users with unbiased, third-party information that
can supplement vendor-provided information. Stakeholder involvement ensures
that user needs and perspectives are incorporated into the test design so that useful
performance information is produced for each of the tested technologies. The technology
categories of interest include detection and monitoring, water treatment, air purification,
decontamination, and computer modeling tools for use by those responsible for protecting
buildings and drinking water supplies and infrastructure, and for decontaminating
structures and the outdoor environment. In addition, environmental persistence
information is also important for containment and decontamination decisions.
The investigation reported herein was conducted by Battelle, under the direction of
NHSRC, as part of the TTEP program. Information on NHSRC and TTEP can be found
at http://www.epa.gov/ordnhsrc/index.htm.
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Acknowledgments
The authors wish to acknowledge the support of all those who helped plan and conduct
the evaluation, analyze the data, and prepare this report. We also would like to thank
Larry Kaelin, EPA National Decontamination Team; Leroy Mickelsen, EPA National
Decontamination Team; Emily Snyder, EPA National Homeland Security Research
Center; and Joe Wood. EPA National Homeland Security Research Center for their
review of this report.
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Contents
Disclaimer ii
Foreword iii
Acknowledgments iv
Abbreviations/Acronyms x
Executive Summary xiii
1.0 Introduction 1
1.1 Objectives for Persistence Testing 1
1.2 Approach 2
1.3 Study Design 2
2.0 Methods 5
2.1 TICs 5
2.1.1 Test Chamber 5
2.1.2 Building Materials 7
2.1.3 TICs, SRSs, and IS 7
2.1.4 Application of TICs to Test Coupons 7
2.1.5 Extraction Method for TICs 8
2.1.6 Analysis Method for TICs 9
2.1.7 Measurement of TICs in Test Chamber Air 10
2.1.8 Calculation of Analytical Recovery and Persistence 10
2.1.9 Statistical Analysis of Persistence and Impact of Fans 12
2.2 CWAs 12
2.2.1 Test Chamber 12
2.2.2 Building Materials 12
2.2.3 CWAs and SRSs 12
2.2.4 Application of CWAs to Test Coupons 14
2.2.5 Extraction Method for CWAs 14
2.2.6 Analysis Method for CWAs 14
2.2.7 Measurement of CWAs in Test Chamber Air 15
2.2.8 Calculation of Percent Recovery and Persistence 15
3.0 Quality Assurance/Quality Control 17
3.1 PE Audit 17
3.2 Technical Systems Audit 17
3.3 Data Quality Audit 17
3.4 QA/QC Reporting 17
3.5 Deviations from Test/QAPlan 17
3.6 Data Quality Indicators 18
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4.0 Results and Discussion 19
4.1 Results for TICs 19
4.1.1 Analytical Method: Recovery of TICs from Building Materials 19
4.1.2 Persistence overTime of TICs on Building Materials 20
4.1.3 Concentrations of TICs in Test Chamber Air 29
4.1.4 Mass Balance of TICs 30
4.1.5 TICs on Building Material Blanks 32
4.1.6 Environmental Conditions During Persistence Tests 33
4.2 Results for CWAs 34
4.2.1 Analytical Method: Recovery of CWAs from Building Materials 34
4.2.2 Persistence Over Tune of CWAs on Building Materials 35
4.2.3 Concentrations of CWAs in Test Chamber Air 42
4.2.4 CWAs on Building Material Blanks 43
5.0 Summary 45
6.0 References 47
Appendix A 49
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Figures
Figure 2-1. Frontal (top) and Overhead (bottom) Views of Test Chamber Used for Persistence Test of TICs 6
Figure 4-1. Recovery of Malathion from Building Materials (Mean conditions fans on: 25 °C and 3 8% RH;
fans off :24°C and 41%RH; error bars are 1 SD) 22
Figure 4-2. Recovery of DMMP from Building Materials (Mean conditions fans on: 25 °C and 36% RH;
fans off: 24 °C and 42% RH; error bars are 1 SD) 23
Figure 4-3. Recovery of TNT from Building Materials (Mean conditions fans on: 25 °C and 37% RH;
fans off:" 25 °C and 3 9% RH; error bars are 1 SD) 24
Figure 4-4. Mean Persistence of Malathion on Building Materials as Percentage of Time 0 Recoveries
(Mean conditions fans on: 25 °C and38%RH; fans off: 24 °C and41%RH) 27
Figure 4-5. Persistence of DMMP on Building Materials as Percentage of Time 0 Recoveries
(Mean conditions fans on: 25 °C and36%RH; fans off: 24 °C and42%RH) 28
Figure 4-6. Persistence of TNT on Building Materials as Percentage of Time 0 Recoveries
(Mean conditions fans on: 25 °C and 37% RH; fans off: 25 °C and 39% RH) 28
Figure 4-7. Accounting for Mass of Malathion 31
Figure 4-8. Accounting for Mass of DMMP 31
Figure 4-9. Accounting for Mass of TNT 32
Figure 4-10. Recovery of GB from Building Materials as Percentage of Time 0 Recoveries
(Mean conditions fans off: 20 °C and 14% RH) 37
Figure 4-11. Recovery of TGD from Building Materials as Percentage of Time 0 Recoveries
(Mean conditions fans off: 21 °C and 22% RH) 38
Figure 4-12. Recovery of VX from Building Materials as Percentage of Time 0 Recoveries
(Mean conditions fans off: 21 °C and 12% RH) 39
Figure 4-13. Persistence of GB, TGD, and VX on Building Materials Compared to Percentage
of Spike Amount Recovered at Time 0 41
Figure 5-1. Mean Persistence (as % of the Day 0 Recovery') of TICs andCWAs on Building
Material Coupons after Seven Days (Error bars are 1 SD) 46
Figure A-1. Real-Tune Gas Phase Malathion Concentration in the Test Chamber with the Fans On 52
Figure A-2. Real-Time Gas PhaseDMMP Concentration in the Test Chamber with the Fans On 52
Figure A-3. Real-Time Gas Phase DMMP Concentration in the Test Chamber with the Fans Off 53
Figure A-4. Real-Time Gas Phase TNT Concentration in the Test Chamber with the Fans On 53
Figure A-5. Real-Time Gas Phase TNT Concentration in the Test Chamber with the Fans Off 54
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Tables
Table ES-1. Persistence of TICs and CWAs in Still Air Conditions xiv
Table 1-1. Physicockemical Properties of Representative TICs and CWAs 2
Table 1-2. Selected TICs and CWAs with Analytical Measurement Parameters 3
Table 1-3. Parameters for Persistence Testing 4
Table 2-1. Building Material Test Coupon Characteristics for TIC Persistence Tests 7
Table 2-2. Source of TICs 7
Table 2-3. Spike Amounts of TICs Applied to Building Material Coupons 7
Table 2-4. Solvent Evaporation Tunes for TIC Spikes in the Analytical Method Recovery Tests 8
Table 2-5. Extraction and Concentration Techniques Used for TICs 8
Table 2-6. GC and MS Conditions for TIC Analyses 9
Table 2-7. GC Retention Times and Monitored Ions for TIC Analyses 9
Table 2-8. Building Material Test Coupon Characteristics for CWATests 13
Table 2-9. Source of CWAs and SRSs 13
Table 2-10. Spike Amounts of CWAs Applied to Building Material Coupons 14
Table 2-11. GC and FPD Conditions for CWA Analyses 14
Table 2-12. GC Retention Times for CWAAnalyses 15
Table 3-1. PE Audit Results 17
Table 3-2. Measurements and Data Quality Indicators for Persistence Testing 18
Table 4-1. Mean Percent Recovery of TICs and Matched SRSs from Building Materials 19
Table 4-2. Comparison of Mean Percent SRS Recoveries by Building Material for Analytical
Method Recovery Tests and Persistence Tests 20
Table 4-3. MDLs for TICs 20
Table 4-4. Mean Recovery of TICs from Building Materials Under Environmental Conditions 21
Table 4-5. Mean Persistence of TICs on Building Materials over Time as Percent of Day 0 Recovery 26
Table 4-6. Air Concentrations of TICs During Persistence Tests 29
Table 4-7. Amount of TIC Vented from Chamber by Air Exchange (7.5 L/min) 29
Table 4-8. Estimate of Distribution of TICs Among Coupons and Vented Air 30
Table 4-9. Amount of TICs on Building Material CouponBlanks 32
Table 4-10. Temperature, RH, and Air Velocity for Persistence Tests (Average ± SD) 33
Table 4-11. Mean Recovery of CWAs and SRSs from Building Materials as Percent of Expected Spike 34
Table 4-12. Comparison of Mean SRS Recoveries by Building Material for Method Recovery
Tests and Persistence Tests 35
Table 4-13. MDLs for CWAs 35
Table 4-14. Mean Recovery of CWAs from Building Materials 36
Table 4-15. Persistence of CWAs on Building Materials over Tune as Percent of Day 0 Spike Recovery 40
Table 4-16. Method Recovery of CWAs from Carboxen™ Sorbent 42
Table 4-17. Air Concentration of CWAs During Persistence Tests 42
Table 4-18. Amount of CWA Vented from Chamber by Air Exchange 42
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Table 4-19. Distribution of CWA Mass Between Known and Unknown Compartments During First
(DayO, 1 h) Sampling Period 42
Table 4-20. Amount of CWA on Laboratory and Procedural Blank Coupons 43
Table 5-1. Trends in Persistence of TICs and CWAs on Building Materials 45
Table A-1. APCI MS/MS Acquisition File Settings 49
Table A-2. Primary and Secondary Transitions for TICs and APCI IS 50
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Abbreviations/Acronyms
APCI MS/MS atmospheric pressure chemical ionization tandem mass spectrometry
BBRC Battelle Biomedical Research Center
C Celsius
cm centimeter
CWA(s) chemical warfare agent(s)
DMMP dimethyl methylphosphonate
ft miir1 feet per minute
EPA U.S. Environmental Protection Agency
FPD flame photometric detection
g gram
GB Sarin
GC gas chromatography
GD Soman
g nr2 gram per square meter
h hour(s)
Ir1 per hour
Hg Mercury
IS internal standard(s)
L liter
M meter(s)
m/z mass-to-charge ratio (dirnensionless)
mm miflimeter(s)
MDL(s) method detection limit(s)
MFC(s) mass flow controfler(s)
min minute(s)
min"1 per minute
mL milliliter(s)
mg milligram(s)
MS mass spectrometry
NA not applicable
NC not calculated
ND not detected
NT not tested
NHSRC National Homeland Security Research Center
ORD Office of Research and Development
ppb parts per billion
ppm parts per million
PE performance evaluation
QA quality assurance
QC quality control
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QMP quality management plan
RH relative humidity
RT retention time
SARM Standard Analytical Reference Material
SRS(s) surrogate recovery standard(s)
SD standard deviation
TBP tributyl phosphate
Temp temperature
TGD thickened soman
TIC(s) toxic industrial chemical(s)
TNT 2,4,6-trinitrotoluene
TSA technical systems audit
TTEP Technology Testing and Evaluation Program
ug microgram(s)
uL microliter(s)
VX VX nerve agent
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Executive Summary
The U.S. Environmental Protection Agency's (EPA's) NHSRC
Technology Testing and Evaluation Program (TTEP) is helping to
protect human health and the environment from adverse impacts
resulting from acts of terror by carrying out performance tests
on homeland security technologies. The persistence of three
different toxic industrial chemicals (TICs) and three different
chemical warfare agents (CWAs), each on various types of
building materials, was investigated at environmental conditions
typical of an office building. In this work, persistence is a relative
term describing a compound's ability to remain over time on the
building material.
This report presents the results of a screening investigation
to determine whether TICs and CWAs of interest persist
sufficiently on selected indoor building materials to allow further
investigation of decontamination technologies that might be
used to remove the chemicals from contaminated surfaces. (A
subsequent report will present the results of the investigation of
decontamination technologies.)
The primary objective of this work was to determine the
persistence of TICs and CWAs at conditions that would provide
a baseline for decontamination technology investigations. While
this also provides data on natural attenuation of TICs and CWAs
from building materials, investigation of causes of persistence
or manipulation of environmental factors to impact persistence
(except for the increased air flow over TICs) was beyond the
scope of this task order. Because fumigation technologies may
include air movement across the coupons, the impact of high air
flow was evaluated for the TICs. In addressing this objective, this
research investigates the following questions:
• Do TICs and CWAs persist on indoor building materials?
• Does air flow over the contaminated building materials
change persistence?
• Do TICs and CWAs persist to such an extent on various
indoor materials to permit testing of decontamination
technologies?
Differences in physicochemical properties of various TICs
and CWAs, as well as the properties of the building materials,
may result in differences in persistence of the chemicals on the
materials. Properties that would be expected to have a significant
impact on persistence include, for example, vapor pressures
and hydrolysis rates. In addition, the physical properties of the
building materials, such as surface area, sorption capacity, and
their relative affinity for water, also have a significant impact on
persistence of TICs and CWAs. This investigation analyzed the
persistence of TICs and CWAs on a variety of building materials.
Three TICs were selected for this effort, including the
organophosphate insecticide malathion, the sarin surrogate
dimethyl methylphosphonate (DMMP), and the explosive
2,4,6-trinitrotoluene (TNT). Three CWAs were also selected.
including sarin (GB), thickened soman (TGD), and VX. The
wide range of vapor pressures and hydrolysis rates for these six
compounds ensured mat persistence on building materials would
vary significantly. The building materials were test coupons
(3.5-10 square centimeters [cm2]) of nylon carpet (absorptive),
decorative rnelamine laminate (nonporous), galvanized metal
ductwork (nonporous), and concrete (porous). Decorative
laminate, carpet and concrete were used with the TICs. Because
of apparent interaction between malathion and concrete,
galvanized metal rather than concrete was used for the CWA
testing. The persistence tests were performed under conventional
building environmental conditions of 22 °C-24 °C and 40%
(TICs) or 17% (CWAs) relative humidity (RH). The duration
of the testing was up to seven days. Persistence tests with the
TICs and CWAs were carried out under conditions simulating
an indoor office building or residential environment, that being
one air exchange rate per hour (Ir1) and no overt air flow over
the surfaces. Additional persistence tests were carried out with
the TICs under these same conditions with the addition of a
continuous rapid air flow at 400 feet per minute (ft min'1) over the
building materials in order to represent the use of industrial fans
for mixing
Methods for extraction and analysis were developed and
validated for TICs and CWAs on building material test coupons
selected for use in this investigation. The analytical work also
included the development of techniques for measuring these
chemicals in the gas phase over test coupons. For the TICs, the
measurement of gas-phase levels involved a real-time mass
spectrometry (MS) technique; for the CWAs this involved time-
integrated air sampling onto Carboxen™ sorbent. The CWA was
extracted from the sorbent with chloroform. Sample extracts
were analyzed using gas chromatography with flame photometric
detection. Air sampling analysis was needed to ascertain the
extent to which persistence was tempered by volatilization
into air and removal at normal ventilation rates. The analytical
methods were sensitive, selective, and reproducible — allowing
detection of levels as low as 0.05% of the initial spike amount
made to each type of test coupon.
The test chambers designed and fabricated for this investigation
incorporated controls for temperature, humidity, air exchange,
and additional air flow over the test surfaces.
The persistence tests were conducted by spiking 400-500
micrograrns (ug) of TICs onto the surface of 3.5-5 cm2 test
coupons, or spiking 1000 ug of CWAs onto 10 cm2 test coupons,
to achieve an initial surface loading of approximately 1 gram per
square meter (g nr2). A loading of 1 g nr2 is representative of a
potential worst-case indoor contamination scenario. The three
different types of test coupons were each spiked sequentially and
expeditiously with the chosen TIC or CWA, and then all coupons
were loaded into the test chamber at the same time. Sufficient
coupons were spiked to allow five replicate test coupons of
each building material to be removed for analysis at each of the
chosen time intervals comprising a persistence test. Additional
test coupons were spiked and not placed into the test chamber,
but extracted immediately to establish a baseline against which
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persistence could be measured. For the TICs, coupons were
removed from the test chamber at Day 1, Day 3, and Day 7 after
spiking. The test coupons spiked with CWAs were removed
at 1 h, 4 h, Day 1, Day 3, and Day 7 after spiking. To assess
redistribution inside the test chamber for the CWAs, procedural
blank coupons were placed in the chamber and removed for
analysis along with the previously spiked test coupons.
The persistence of the chemicals on test coupons in relatively
still air (one air exchange rate per hour) in the test chamber is
summarized in Table ES-1 below. The percent persistence is
the mean mass of TIC or CWA recovered from the coupons at a
given time divided by the mean mass of TIC or CWA recovered
from coupons at Time 0 x 100%. The persistence of malathion
and TNT on industrial carpet and concrete was approximately
equal with either the fans on or the fans off (still air); however,
on laminate, the persistence was approximately half with the fans
on. The persistence of the CWAs was not tested under conditions
with fans directing air over the surfaces of the building materials.
The persistence on industrial carpet and laminate coupons was
apparently related to the vapor pressure of the TIC or CWA, with
the most volatile ones exhibiting lowest persistence. A similar
trend was observed for the persistence of the CWAs on the metal
ductwork coupons. The persistence of the TICs on concrete may-
be a function of several factors. The malathion may be lost due
to a heterogeneous hydrolysis reaction, as the CWA VX, which
has a chemical structure similar to malathion, has been shown
to hydrolyze on concrete.11'21 Given the structural similarities
between VX and malathion, a similar hydrolysis reaction may
occur between malathion and concrete. DMMP was essentially
retained on the concrete; the lower persistence of less-volatile
TNT cannot be fully explained at this time, unless basic sites on
the concrete facilitated hydrolysis or degradation.
Measurement of the gas-phase concentration of the TICs and the
CWAs in the test chamber air showed that there were quantifiable
levels of these compounds present. However, levels in the air
accounted for less than 5% of the total mass of TIC or CWA
originally placed into the chamber. The procedural blank coupons
placed in the chamber during the CWA persistence tests showed
that gas phase material was redistributed to sorptive surfaces, as
levels on the carpet procedural blanks were much higher than
those on laminate or ductwork procedural blank coupons. At the
end of the seven-day test period, as much as 76% of the DMMP,
58% of the malathion, and 50% of the TNT were not accounted
for by residual levels remaining on test coupons and the volatile
chemicals measured in the air of the test chamber. These results
suggested that in real-world decontamination scenarios it would
be essential to take into account that certain TICs and CWAs do
volatilize and that certain building materials may have a greater
affinity or capacity than others to retain one or more chemicals.
Furthermore, the volatilized compounds may adsorb onto or
absorb into other materials.
Table ES-1. Persistence of TICs and CWAs3 in Still Air Conditions
Duration
Malathion
DMMP
TNT
GB
TGD
VX
Persistence on Carpet, % remaining of initial mass ± SD (n=5)
Ih
4h
Day 1
Day 3
Day 7
-
-
103 ±3
94 ±3
85 ±3
-
-
16 ±3
11 ±2
7±2
-
-
80 ±7
84 ±8
61±8
18 ±4
9±4
3. 3 ±2.6
2.0 ±1.2
0.4 ±0.5
84 ±47
43 ± 3
12 ± 1
12 ± 7
4±0
103 ±8
101 ±18
88 ±6
36 ±3
18±1
Persistence on Laminate, % remaining of initial mass ± SD (n=5)
Ih
4h
Day 1
Day 3
Day 7
-
-
97 ±3
87 ±6
72 ±3
-
-
0.5 ±0.4
0.5 ±0.1
0.2 ±0.3
-
-
69 ±11
68 ±17
45 ±13
Not Detected
at 5 min
17±4
0.28 ±0.01
0.11 ±0.04
ND, <0.1
ND, <0.1
99 ±7
105 ±28
52 ±4
8±4
4±3
Persistence on Concrete, % remaining of initial mass ± SD (n=5)
Day 1
Day 3
Day 7
46 ± 10
17 ±11
7± 4
106 ±7
87 ±4
99 ±5
81 ± 19
85 ±21
57 ± 9
-
-
-
-
-
-
-
-
-
Persistence on Metal Ductwork, % remaining of initial mass ± SD (n=5)
111
4h
Day 1
Day 3
Day 7
-
-
-
-
-
-
-
-
-
-
-
-
.
-
-
Not Detected
at 15 min
41 ±12
1.39 ±0.23
0.91 ±0.13
0.91 ±0.33
0.51 ±0.04
97 ± 5
117 ±24
89 ± 5
55 ± 20
24 ± 8
a TICs and CWAs on various materials were exposed to conditions simulating an indoor
environment, that being one air exchange fr1 and no overt air flow over the surface.
- Not tested
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1.0
Introduction
The EPA's NHSRC is helping to protect human health and the
environment from adverse impacts resulting from intentional acts
of terror. With an emphasis on decontamination and consequence
management, water infrastructure protection, and threat and
consequence assessment, NHRSC is working to develop tools
and information that will help detect the intentional introduction
of chemical, radiological, or biological contaminants into
buildings, subways, water systems, or outdoor environments;
contain these contaminants; decontaminate these environments;
and facilitate the disposal of material resulting from cleanups.
NHSRC's TTEP 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 in carrying
out performance tests on homeland security technologies. The
program evaluates the performance of innovative homeland
security technologies by developing test plans that are responsive
to the needs of stakeholders, conducting tests, 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 high
quality are generated and that the results are defensible. TTEP
provides high-quality information that is useful to decision
makers in purchasing or applying the tested technologies. It
provides potential users with unbiased, third-party information
that can supplement vendor-provided information. Stakeholder
involvement ensures that user needs and perspectives are
incorporated into the test design so that useful performance
information is produced for each of the tested technologies.
Inherent characteristics of chemicals, such as volatility or the
ability to react with surface materials, may result in the low
persistence of chemicals on given surfaces. If chemicals do not
persist on a given surface, investigations of decontamination
technologies against such chemical-surface combinations would
not generate useful information. Therefore, screening tests were
needed prior to performing the systematic decontamination
investigations in order to ensure that only useful combinations
of chemicals and building materials were included in the
decontamination investigation. This report presents the results
of a screening investigation to determine whether TICs and
C WAs of interest persist sufficiently on selected indoor building
materials to allow further investigation of decontamination
technologies that might be used to remove the chemicals from
contaminated surfaces.
1.1 Objectives for Persistence Testing
This testing was conducted to measure the persistence, under
conventional indoor building conditions, of three representative
TICs and three representative C WAs on a range of indoor
building materials. The primary objective of this work was
to determine the persistence of TICs and CWAs at conditions
that would provide a baseline for decontamination technology
investigations. Investigation of causes of persistence or
manipulation of environmental factors to impact persistence
(except for the increased air flow over TICs) was beyond the
scope of this task order. Because fumigation technologies may
include air movement across the coupons, the impact of high air
flow was evaluated for the TICs. Persistence in this investigation
was assessed by quantifying the amount of TIC or CWA extracted
at different times from test coupons of the selected building
materials, which had been initially spiked with known quantities
of a TIC or CWA. In other words, persistence is a relative term
describing a compound's ability to remain, or persist, over time
on the test coupons.
To address the objective, this research investigates the following
questions:
• Do TICs and CWAs persist on indoor building materials?
• Does air flow over the contaminated building materials
change persistence?
• Do TICs and CWAs persist to such an extent on various
indoor materials to permit testing of decontamination
technologies?
Differences in physicochemical properties of various TICs and
CWAs, as well as the properties of the building materials, may-
result in differences in persistence of the chemicals on building
materials. Properties that would be expected to have a significant
impact on persistence include, for example, vapor pressures
and hydrolysis rates. In addition, the physical properties of the
building materials, such as surface area, sorption capacity, and
their relative affinity for water, also have a significant impact on
the persistence of TICs and CWAs. This investigation analyzed
the persistence of TICs and CWAs on a variety of building
materials. Physicochemical properties of representative TICs and
CWAs are listed in Table 1-1.
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Table 1-1. Physicochemical Properties of Representative TICs and CWAs
Property
Molecular weight, g/mole
Melting point. °C
Boiling point, °C
Vapor pressure, millimeter (nun) Hg at 25 °C
Hydrolysis rate, half-life, days
Octanol: water partition; Log Kow
TICs
Malathion
330.3
2.8
157
3.38e-06
21
2.36
DMMPa
124.8
-50
181
1.2
NAe
0.5
TNT"
227.1
80.9
240
8.0e-06
730
1.6
CWAs
GBC
140.0
-56
158
2.9
1.6
0.3
TGDd
182.2
-42
198
0.4
1.9
1.78
VX
267.4
-39
300
6.3e-04
42
2.09
a DMMP = dimethyl methylphosphonate
b TNT= 2.4,6-trinitrotoluene
c GB= sarin
d TGD = GD tliickened with polymethyl metliacrylate; thickened soman
e NA= not available
1.2 Approach
The general approach developed and used for persistence testing
was to apply a known amount of each TIC or CWA to each of
several test coupons of the same building material and allow
these spiked test coupons' surfaces to age under controlled
environmental conditions. At specified intervals, replicate
test coupons were extracted and the extracts were analyzed to
determine the amount of the TIC or CWA that remained on the
test coupon at that specific time.
The approach developed and applied for testing the persistence
of TICs and CWAs was generally the same, and therefore this
section gives information that is applicable to persistence testing
that was performed for both TICs and CWAs. The specific details
for the methodologies used to test the persistence of TICs and
CWAs are described in Section 2.0.
The scope of the study was to screen TICs and CWAs to ensure
that the chemicals exhibited adequate persistence on the selected
materials to support decontamination testing. The results also
served as a baseline for comparison with the application of
decontamination technologies in later investigations. A systematic
investigation of other factors that are likely to affect persistence
(e.g., ambient temperature effect or changing RH) was not
performed because it was beyond the scope of this screening
study.
1.3 Study Design
Table 1-2 includes the TICs and CWAs mat were selected for
this study. It also includes important elements of the analytical
methods used for each compound, including the surrogate
recovery standard (SRS) used to track extraction efficiency
and analytical recovery, and the internal standard (IS) used for
quantification (see Section 2.0). As described further in Sections
2.0 and 4.0, the SRS for each TIC or CWA is an important
element of the analytical plan used here. Each SRS was chosen
for its structural similarity to a given analyte; its recovery was
used to correct for variation in extraction efficiency and recovery
through the analytical method. Table 1-2 also includes the general
analysis method employed for extracts of building materials,
as well as the sampling and analysis methods employed in
measuring the chemicals in the air over the building materials
during persistence testing.
The building materials used in this persistence investigation
included industrial grade carpet, laminate countertop material,
unpainted concrete, and galvanized metal ductwork. The
objective was to find a combination of building materials and
chemicals on which the chemicals were persistent and from
which the chemicals could be efficiently recovered. As will be
discussed, preliminary work with TICs showed that malathion
(a surrogate for VX) appeared to react with concrete. Given
these results, an alternate building material (galvanized metal
ductwork) was evaluated for use with the CWAs.
Building materials were cut into coupons of small, defined size,
and the toxic chemicals were applied at a rate equivalent to 1
g nr2, which is representative of a potential worst-case indoor
contamination scenario. The coupons to which TICs were applied
were approximately 5 cm2, and the coupons to which CWAs were
applied were approximately 10 cm2. The sizes were chosen so as
to take advantage of the available area in the test chambers and
to optimize the spiking volume of chemicals being applied to the
coupons.
All testing with TICs was carried out in standard chemical
laboratories at Battelle. Due to the stringent controls needed for
working with CWAs, persistence tests for CWAs were carried
out at Battelle's certified chemical surety facility (Battelle
Biomedical Research Center [BBRC]) in West Jefferson, Ohio).
The persistence tests were conducted with coupons inside
specially fabricated test chambers with controls for air exchange
rate (see Section 2.1). The persistence of each chemical (TIC or
CWA) was investigated separately; however, the behavior of a
given chemical was investigated on all building material coupon
types simultaneously.
-------
Table 1-2. Selected TICs and CWAs with Analytical Measurement Parameters
Parameter
SRS
IS
Extraction
Analysis
Air sample
collection
Air sample
analysis
TICs
Malathion
Fenchlorphos
DBBd
Sonication
GC/MS8
Real-time head
space1
APCI
MS/MS1
DMMP
DEEP3
DIMPe
Sonication
GC/MS
Real-time head
space
APCI MS/MS
TNT
TNBb
3-NBPf
Sonication
GC/MS
Real-time head
space
APCI MS/MS
CWAs
GB
TBPC
DIMP
Shake/stand
GC/FPDh
Carboxen™
sorbent
GC/FPD
TGD
TBP
DIMP
Shake/stand
GC/FPD
Carboxen™
sorbent
GC/FPD
VX
TBP
DIMP
Shake/stand
GC/FPD
Carboxen™
sorbent
GC/FPD
a DEEP = diethyl ethylphosphonate
b TNB = 1,3,5-trinitrobenzene
0 TBP = tributyl phosphate
d DBB = dibromobiphenyl
e DIMP = diisopropyl methylphosphonate
f 3-NBP=3-nitrobiphenyl
8 GC/MS = gas chromatography/mass spectrometry in the multiple ion detection mode
h GC/FPD = gas chromatography/flame photometric detection
1 Real time = monitoring of headspace (air) in the chamber in real time
J APCI MS/MS = atmospheric pressure chemical ionization tandem mass spectrometry
-------
Table 1-3 presents a summary of the matrix of building materials
and chemicals, together with the test chamber conditions that
were used in the persistence testing. For TICs. persistence of each
TIC was tested under two sets of conditions—with and without
air flow over the coupons.
Preliminary tests carried out to assess recovery of CWAs from
ceiling tile provided some insights into persistence on this
building material (see Section 4.2.1). The temperature and
humidity in the chamber, the air exchange rate in the chamber,
and the times at which test coupons were removed for analysis
were physical factors manipulated in the investigation of the
persistence of TICs and CWAs. For the persistence testing of
TICs, two fans were placed inside the test chamber such that,
when activated, air passed over the coupons at approximately
400 ft min"1. This additional air flow over the coupons served to
simulate the use of fans during decontamination, for example to
distribute or cycle fumigant. The increased rate of volatilization
of chemicals from various materials due to the increased air speed
might decrease their persistence and confound decontamination
testing. The results from the TICs testing were considered
sufficient to understand the impact of air speed on persistence of
volatile and relatively nonvolatile chemicals on various types of
materials. Therefore, no CWA persistence tests were conducted
with high air flow over the coupons.
The temperature and RH inside the test chambers and air
velocity over the coupons (for TICs) were monitored and
recorded. The air flow into the chambers, and therefore, the air
exchange rate, was constantly controlled. Five replicate coupons
of each building material type were analyzed at each time point,
for each chemical.
Throughout each trial, the amount of TIC or CWA in the gas
phase in the test chamber was measured using either atmospheric
pressure chemical ionization tandem mass spectrometry
(APCI-MS/MS) or collection of a known quantity of air on a
Carboxen™ sorbent tube. In the latter case, the sorbent was
extracted and the resultant extract was analyzed for the CWA.
Table 1-3. Parameters for Persistence Testing
Chemical
Building
Materials
Temperature,
RH Maintained
Air Exchange
Rate
Air Flow
over Coupons
Sampling Points
in Time
TIC
Malathion
DMMP
TNT
Carpet
Laminate
Concrete
Carpet
Laminate
Concrete
Carpet
Laminate
Concrete
24 °C,
40% RH
24 °C,
40% RH
24 °C,
40% RH
lh-'
llr1
llr1
Oftmin-1
400 ft min-1
0 ft min-1
400 ft miir1
0 ft min-1
400 ft min-1
0 h. Day 1, 3, 7
0 h, Day 1, 3, 7
0 h. Day 1, 3, 7
CWA
GB
TGD
VX
Carpet
Carpet
Laminate
Ductwork
Carpet
Laminate
Ductwork
22 °C,
17% RH
22 °C,
17%RH
22 °C,
17% RH
llr1
llr1
lh-1
Oftmin-1
0 ft min-1
0 ft min-1
0 h, 1 h, 4 h,
Day 1, 3, 7
0 h, 1 h, 4 h.
Day 1, 3, 7
0 h. 1 h. 4 h.
Day 1, 3, 7
-------
2.0
Methods
All testing was performed in accordance with the peer-reviewed
and EPA-approved Test/QA Plan for the Systematic Evaluation
of Technologies for Decontaminating Surfaces Inoculated with
Highly Hazardous Chemicals (Chemical Warfare Agents and
TICs), Manipulation of Environmental Conditions to Alter
Persistence, Version 7[3) as amended to include Appendices 1
and 2.
2.1 TICs
2.1.1 Test Chamber
A customized test chamber consisting of fabricated and off-
the-shelf equipment and components was assembled and
used to carry out all experiments for persistence of TICs. The
448-liter (L) test chamber (Labconco) is shown hi Figure 2-1.
The temperature hi the chamber was maintained between 24 °C
and 25 °C. Zero air (nominally hydrocarbon-free air with
approximately <0.1 ppm hydrocarbons) was supplied to the test
chamber by a zero air generator (AADCO). To achieve an air
exchange rate of one h"1, the total air flow into the test chamber
was set to 7.5 L miff1, using two separate 0-10 L miff1 mass
flow controllers (MFC; Sierra Instruments). One MFC admitted
moisture-free air to the test chamber at a rate of 4.25 L miir1.
Dry air was metered through the second MFC, passed through a
humidity generator (10 L miff1 model, Fuel Cell Technologies),
and admitted into the test chamber at 3.25 L miff1. At these
two flow rates, the RH was maintained at 40%. A small 8-cni
fan (Papst Model 8412), mounted hi the upper left side of the
chamber, was used to circulate and mix the gas phase components
of the test chamber atmosphere. Temperature and RH in the test
chamber were monitored in real time, using a National Institute
of Standards and Technology-traceable therniohygrometer
(Traceable Hygrometer, Model 4185, Control Company). During
testing, approximately 4 L miff1 of the test chamber air was
withdrawn into the APCI MS/MS instrument for monitoring the
gas phase TIC concentration. The remainder of the test chamber
effluent (3.5 L miff1) was directed to vent.
The building material coupons were placed on a custom-
fabricated polycarbonate carousel that was mounted inside
the test chamber, as shown in Figure 2-1. Two 8-cm fans were
positioned directly above the carousel in a straight line along
the carousel diameter so as to pass air directly above the coupon
surfaces. The carousel completed one full rotation each minute
(inin). The operation of the carousel was controlled to ensure that
air was passed across all coupons as uniformly as possible for the
duration of each seven-day test. Each of the two fans produced
an air velocity of 400 ft miff1 as measured by anemometers (TSI
model 8455) 1 to 2 mm above the carousel (very nearly at or just
below the surface of the coupons) placed downstream of each of
the two carousel fans.
The test chamber included an air lock through which coupons
could be removed at the end of a given time interval while
minimizing disturbance to the test chamber atmosphere.'41
-------
Figure 2-1. Frontal (top) and Overhead (bottom) Views of Test Chamber Used for
Persistence Test of TICs
I Temperature/Humidity
Mixing
Relative
Anemometer
-------
2.1.2 Building Materials
The test coupons used (see Table 2-1) included both porous
(concrete and industrial grade carpet) and nonporous (decorative
laminate) surfaces representing a variety of building materials.
Test coupons were cut (to the sizes indicated in Table 2-1)
from larger pieces of stock material. Each coupon was visually
inspected prior to being used in any experiment or test. Coupons
with anomalies on the application surface were discarded.
2.1.3 TICs, SRSs, and IS
The source, lot number, and purity of each TIC used for the
recovery experiments and persistence tests are listed in the upper
section of Table 2-2; these parameters are also listed in the lower
section of Table 2-2 for die secondary source material used in the
QA performance evaluation (PE) audit.
The surrogate recovery standards (SRSs; see Table 1-2) were
obtained from multiple sources: fenchlorphos and DEEP from
ChemService and TNB from Aldrich. The IS for quantification
(see Table 1-2) were also obtained from multiple sources: DBB
and 3-NBP from Aldrich and DIMP from Cerilliant.
2.1.4 Application of TICs to Test Coupons
For both analytical method recovery testing and persistence
testing, the test coupons were each spiked with individual TICs to
achieve a loading of ~1 g nr2. These levels are listed in Table 2-3.
Table 2-1. Building Material Test Coupon Characteristics for TIC Persistence Tests
Material
Decorative Laminate
Industrial-grade Carpet
Concrete,
Retaining Wall
Lot, Batch, or
Observation
Laminate/ Formica/
White Matte Finish
ShawTek,
EcoTek 6
Five parts sand:
two parts cement
Manufacturer/
Supplier Name
Solid Surface Design
Shaw Industries, Inc
Wysong Concrete
Approximate Coupon Surface
Size, L x W, in cm
3.5x1.5
(5.25 cm2)
3.5x1.5
(5.25 cm2)
3.5x1.0
(3.5 cm2)
Table 2-2. Source of TICs
Chemical
Manufacturer/
Supplier Name
Lot Number
Purity or
Concentration
Concentration as
Applied
Materials used for recovery experiments and persistence tests
Malathion
DMMP
TNT
ChemService
Aldrich
Battelle magazine
343-1 10B
10110EA
Unknown
99.2%
97%
Unknown
10 mg mL~4n acetone
10 mg nuVin acetone
10 mg ml/'in acetone
Materials used for QA performance audit
Malathion
DMMP
TNT
ChemService
ChemService
Restek
332-16B
08113TC
A033065
98%
97%
1000 ug/mL
(in acetonitrile)
NAa
NA
NA
' NA= Not applicable
Table 2-3. Spike Amounts of TICs Applied to Building Material Coupons
Coupon Type
Carpet
Laminate
Concrete
Coupon Size, cm2
5.3
5.3
3.5
Spike Volume
50iJLof lOmgmL-1
50(.iLof lOmgmL-1
40u.Lof lOmgmL-1
Spike Amount, ug
500
500
400
-------
The addition of 500 ug of a TIC to carpet or laminate coupons is
equivalent to 0.5 mg per 5.3 cm2, or about 1 mg per 10 cm2 or 1
g m~2. Similarly, the addition of 400 ug to a concrete coupon is
equivalent to 0.4 mg per 3.5 cm2, or about 1 mg per 10 cm2 or 1 g
nr2. The spike of each TIC was delivered from a variable volume
pipettor (Eppendorf) onto each test coupon in a laboratory' fume
hood separate from the test chamber. Laboratory blank coupons
were not exposed to TICs or to the laboratory atmosphere in
which the test chamber resides. Instead, when the coupons were
retrieved from storage, one coupon of each type was placed
immediately into an airtight vial for subsequent extraction as a
method laboratory blank coupon. All other coupons retrieved
from storage were placed in the fume hood where the test
coupons and positive controls were spiked. The procedural blank
coupons were not spiked but were in the hood during the spiking
and handling of the test coupons.
For the analytical method recovery tests, the TIC and SRS
solutions were spiked onto the coupons just prior to extraction.
In this way, the recovery of each shows the extent to which the
combined extraction efficiency and analytical recovery of the
SRS agrees with that of its matched TIC. A short drying time
was used to allow the solvent to evaporate before extraction.
Similarly, for persistence tests, the coupons were placed in the
laboratory' fume hood and spiked with the TIC solution. The
solvent was allowed to evaporate before the coupons were placed
in the test chamber. The solvent evaporation times, listed in
Table 2-4, were selected on the basis of the TIC and coupon type.
Evaporation tune was selected based on the relative volatility
of the chemical and the porosity of the substrate. Longer drying
time (and soak-in time) was provided for less volatile chemicals
(TNT and malathion) on porous materials (carpet and concrete).
A short drying time was used for volatile DMMP on all materials.
The test chamber was already equilibrated at the appropriate
temperature, RH, and air flow when the coupons were added. For
the persistence tests, the SRS was not spiked onto each coupon
until after coupons were removed from the test chamber, just
before analytical extraction. For the analytical method recovery'
tests, the TIC solution was spiked onto the coupons and the
solvent allowed to evaporate as indicated in Table 2-4. As with all
other coupons, SRS was not spiked onto these coupons until just
prior to extraction.
2.1.5 Extraction Method for TICs
For extraction, each coupon was placed into a 22-mL amber glass
vial and then spiked with 25 microhters (uL) of a 10-ug uL'1
solution of the appropriate SRS (to deliver 250 ug). A20-mL
aliquot of acetone was added to each vial; the vial was sealed
with a screw-cap lid and sonicated for 30 min in an ultrasonic
bath (Branson 5510). The extract was decanted through a quartz
fiber filter (Pallflex QAT-UP) to either a 200-mL TurboVap tube
or a 25-rnL Kuderna-Danish tube with attached 125-mL reservoir.
Carpet and concrete samples were extracted with three replicate
aliquots of acetone; extracts were combined before concentration.
Laminate coupons required only one extraction cycle. The
number of extraction cycles and the concentration technique
used for each TIC and building material combination are listed in
Table 2-5. Extracts were concentrated to a final volume of 5 mL
and spiked with 25 uL of a 10-ug uL'1 solution of the appropriate
IS (see Table 1.2) to give a 50-ug mL'1 concentration. The extract
was then filtered through a disposable syringe filter (GD/X;
Whatman) prior to the GC/MS analysis.
Table 2-4. Solvent Evaporation Times for TIC Spikes in
the Analytical Method Recovery Tests
TIG
TNT, Malathion
TNT, Malathion
DMMP
Material
industrial Grade Carpet
Concrete Retaining Wall
Decorative Laminate
Decorative Laminate,
Industrial Grade Carpet
Concrete Retaining Wall
Evaporation Time,
min
30
3
1
Table 2-5. Extraction and Concentration Techniques Used for TICs
Coupon Type
Carpet, Concrete
Carpet, Concrete
Laminate
Laminate
TIC
TNT, Malathion
DMMP
TNT, Malathion
DMMP
Extraction
Technique
Sonication
Sonication
Sonication
Sonication
Extraction
Acetone; 3 x 20 mL
Acetone; 3 x 20 mL
Acetone; 1 x 20 mL
Acetone; 1 x 20 mL
Concentration
Technique
Turbo Vap
Kuderna-Danish
Turbo Vap
Kuderna-Danish
-------
2.1.6 Analysis Method for TICs
Sample extracts were analyzed using GC/MS in selected ion-
monitoring mode on an Agilent 6890/5973 GC/MS. Data
collection, reduction, and analysis were performed using Agilent
Chemstation software, version B.02.05. The GC and MS
conditions used for analyses of the three different TICs are listed
in Table 2-6.
Two ions were monitored for each TIC, SRS, and IS. The
primary ion was used for quantification, and the secondary ion
was used for qualitative confirmation of identification. Criteria
for identification of an analyte included the correct GC retention
time (RT) ±0.02 min chromatographicaUy co-maximized primary
and secondary ions and the correct ratio of the intensity of
the primary and secondary ions. The monitored ions and GC
retention times are listed in Table 2-7.
The quantification was performed using the IS method.151
The IS was present at the same concentration in all samples
and standards. The 11-point calibration curve spanned the
concentration range of 0.1-150 ugml/1. This concentration
range is equivalent to 0.1% to 150% recovery of the spike
amount used in recovery tests and persistence tests. R2 values for
all regression curves were greater than 0.990.
The full calibration curve was generated at the start of each
analysis set. Then samples were analyzed with the 20-ug ml/1
standard nin after every five samples as a continuing check on
the calibration. If the calculated concentration of the continuing
calibration standard was more than 20% different compared to its
true concentration, the cause of the problem was investigated and
the five samples before and after this standard were reanalyzed.
Calibration curves were constructed using a quadratic least-
squares regression analysis routine with the weighting scaled
by the inverse of the analyte concentration. Typically, the
calibration data could be fitted to a single curve for malathion
and DMMP. However, due to the wide calibration range,
occasionally two separate calibration curves (one with high
values and one with low values) were needed to define the
malathion calibration data. TNT data was fitted with two 6-point
calibration curves, one covering 0.1 to 5 ug ml/1 and the other
covering 5 to 150 ug inl/1.
Table 2-6. GC and MS Conditions for TIC Analyses
Parameter
GC column'
Inlet liner
Temp program for malathion
Temp program for DMMP
Temp program for TNT
GC injection
Transfer line temp
MS source temp
Quadruple temp
Condition
DB-1701; 30 m x 0.25 mm ID 0. 15 urn film thickness; J&W Scientific
Siltek double goose neck
100 °C (2 min); 100 °C-180 °C &. 10 °C/min; 180 °C-220 °C @ 5
°C/min; 220 °C-260 °C @ 20 °C/min (20 nun run time)
50 °C (2 min); 50 °C-95 °C @. 3 °C/min; 95 °C-250 °C @ 20 °C/min:
hold 2.25 min (27 min run time)
100 °C (2 min); 100 °C-180 °C @ 10 °C/min; 180 °C-210 °C @ 5
°C/min; 210 °C-260 °C @ 15 °C/min; hold 3 min (22.3 min runtime)
1 uL splitless at 280 °C
280 °C
230 °C
150 °C
' In all cases, helium was the carrier gas: 0.8 ml. min"1 flow for malathion; 1 ml, min"1 for DMMP
and TNT.
Table 2-7. GC Retention Times and Monitored
Ions for TIC Analyses
Chemical
Malathion
SRS
IS
DMMP
SRS
IS
TNT
SRS
IS
GC RT, min
17.2
15.5
16.5
9.0
17.0
15.6
14.8
15.5
14.6
Ions Monitored, m/z
Quantification ion
173
285
312
94
111
97
210
213
199
Qualifier ion
127
125
152
79
93
123
§9
75
152
-------
2.1.7 Measurement of TICs in Test Chamber Air
Throughout each test, approximately 4 L miir1 of air from the test chamber was continuously withdrawn and
introduced to the Perkin Elmer Sciex APCI MS/MS for quantification of the TIC air concentration in real time.
Multipoint calibration curves, consisting of a minimum of six points, were generated at the beginning and end of
each seven-day test period for each TIC. The responses comprising the two curves were averaged and the resultant
mean response factor was used to quantify the TIC. For calibration, known amounts of a specific TIC were admitted
to the APCI MS/MS at a known rate; the delivery method depended on the volatility of the TIC. For malathion
and TNT, dilute aqueous solutions of varying concentration (typically from 0.1 to 10 ug ml/1) were prepared and
directed into the MS source through a custom-built vaporizer at a known flow rate (typically 5 to 15 rnL h"1) using a
syringe pump. As the air flow into the APCI MS/MS was constant, variation of the aqueous concentration and liquid
delivery rate allowed for different gas-phase concentrations to be delivered to the MS/MS. For the higher volatility
DMMP, the effluent from a diffusion tube containing DMMP maintained at a constant temperature in a permeation
oven was introduced to the MS/MS source in vary ing amounts through a heated transfer line. That is. in order to
generate a multipoint calibration curve, the amount of DMMP delivered to the APCI inlet was adjusted by varying
the fraction of the oven air stream that was vented away from the transfer tine and replaced with DMMP-free
makeup air.
The TIC concentration was calculated using the measured MS/MS response and the mean response ratio from the
appropriate calibration curves. Further discussion of this analysis method is presented in Appendix A.
2.1.8 Calculation of Analytical Recovery and Persistence
The analytical method performance recovery was determined initially for both the TIC and its matched SRS
according to the following formula:
Concentration of extract us ImL x Extract volume, mL
Analytical Method (Raw) Recovery.% - J ^S !_= x 100% (1)
Mass applied, fig
In many analytical methods, an isotopically labeled chemical version of an analyte (e.g.. labeled with deuterium-
or carbon-13) is used as the SRS; in that case the analyte and SRS are generally recovered through an analytical
method to the same extent because among the population of native and labeled molecules, there is no discernible
difference in losses between the native and labeled versions with respect to the types of analytical procedures.
In this case, the SRS recovery in each particular sample is used to correct for extraction efficiency and analytical
method losses. Where an isotopicafly labeled version of the analyte is not available, an SRS is chosen to be as
similar as possible to a given analyte so as to minimize the potential for differential loss mechanisms between the
two compounds. When the SRS and the analyte are not a perfect match to one another, the correction addressed by
the SRS recovery needs to be modified by the relative ratio of SRS to analyte recovery. This ratio of SRS to TIC
recovery was taken from the recovery measurements of these compounds in the method performance tests.
The analytical method recovery, calculated as shown in Equation 1, for the TIC and its matched SRS was
determined, and the ratio of the means of those recoveries were used in Equation 2 to determine the ratio of the SRS
recovery to the TIC recovery.
Mean analytical method SRS recovery, %•
SRS I TIC Recovery Ratio = —— (2)
Mean analytical method TIC recovery, %
The (raw) recovery' of the individual TIC or SRS (calculated using Equation 1) from a building material coupon
during a persistence test was corrected by its corresponding SRS (raw) recovery (calculated using Equation 1)
and the SRS/TIC recovery ratio (calculated in Equation 2). This resulted in the TIC corrected recovery calculated
according to the following equation:
,,.„,,, TIC (ran ) recovery, % ,
//( Corrected Recovery, % = - x SRS/ IK recovery ratio x 100% (3)
SRS (ra\v)recovery, %
-------
The TIC corrected recovery at each sampling interval, calculated using Equation 3, was then used to calculate
percent persistence as shown in Equation 4. The percent persistence at each time point, calculated as shown in
Equation 4. represent the primary outcome of this investigation. These results are presented graphically as percent
persistence versus time.
TIC corrected recovery at time ,
Persistence, % - - - - - x 1 00% (4)
ifC corrected recovery at time 0
The calculation of the level of a TIC in a blank coupon was calculated according to the following formula:
Blank Level, % of Spike -
TIC concentration in blank extract, pg/mLx Extract volume, mL Average SRS recovered (5)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ X ^^^^^^^^^^^^^^^^^^^^^^^^^^~ X I UU /fl
Mass of TIC applied So lest coupons, pig x SRS recovery, % Average TIC recovered
To convert a gas-phase TIC concentration from parts per billion (ppb) to a mass concentration at one atmosphere of
pressure and 25 °C, the following equation'61 was used:
_ 3 Concentration, ppb
Concentration tn air, itg m - (6\
0.0409 x Molecular Weight
For the TICs, a calculation of mass balance was carried out to determine the extent to which measurements of the
TICs on the coupons and in the chamber air (and in the air that was vented to maintain the air exchange rate) could
account for the known amount of the TICs initially spiked onto the coupons.
This mass balance assessment required calculation of the total amount of TIC applied to coupons that were in
the chamber at each test interval and the total amount of TIC remaining on those coupons at the end of each test
interval. The total mass of spiked TIC was the sum of the spiked mass on the carpet, laminate and concrete coupons,
according to the following equation:
i
Mass of spiked TIC, mg = \ spiked mass on coupon typek (7)
r— I
The mass on each coupon type was:
Spiked mass on coupon type x ~ # coupons of type ^ at time y x spike amount per coupon, mg (g)
For example, 0.5 mg was spiked onto each carpet and laminate coupon and 0.4 mg was spiked onto each concrete
coupon. There were five replicate coupons of each type for each of the three time intervals (Day 1, Day 2-3, and
Day 4-7). On Day 1, with 45 coupons in the chamber, there was a total of 2 1 mg of a given TIC on all coupon types
in the chamber. After removal of 15 coupons at the end of Day 1, there was a maximum of 14 mg of that TIC on
coupons during the test interval of Day 2-3. Then, after removal of another 15 coupons at the end of Day 3, there
was a maximum of 7 mg of that TIC on coupons during the test interval of Day 4-7.
The percentage distribution on the coupons at the end of a test interval was the amount recovered from the coupons
at that time interval divided by the amount originally spiked onto the coupons present in that test interval. The
percentage distribution in the air was the amount of the TIC in the vented air divided by the amount originally
spiked onto the coupons present in that test interval. The sum of these two percentages was subtracted from 100%
to obtain the percentage of the mass that was not accounted for in these two known compartments (coupons and
air). The unaccounted for mass may have been distributed between compartments such as the chamber walls and
degradation products.
-------
2.1.9 Statistical Analysis of Persistence and
Impact of Fans
The TIC persistence data calculated using Equation 4 were
used in a statistical analysis to determine whether there was a
statistically significant difference between persistence at the start
of the experiment (Time 0) and at the end of the test interval
(after seven days) (i.e., was there a reduction in persistence
over the course of the evaluation?) and whether there was a
statistically significant difference in persistence after seven days
with fans on and with fans off for each combination of TIC and
building material.
The first objective was evaluated with a one-sample t-test, with
the p-value reported. The p-value is the probability of finding, by
chance, a result as extreme or more extreme than that observed
if the preliminary assumption of no loss of persistence is
true. P-values less than 0.05 mean that there was at least 95%
confidence that the persistence after seven days was lower than
persistence at Time 0.
The second objective was evaluated with a two-sample t-test,
with the p-value reported. The p-value is the probability of
finding, by chance, a result as extreme or more extreme than
that observed if the preliminary assumption of no difference
in persistence between the fans on and fans off conditions is
true. P-values less than 0.05 mean that there was at least 95%
confidence that the persistence was different between the two
tested conditions. For the two-sample t-test, a preliminary test
was conducted to determine whether there was a statistically
significant difference in the variability of the data for the two
conditions (fan on and fan off). If no significant difference was
found, the t-test was performed with a variance estimate formed
by pooling the data for the two conditions. If a significant
difference was found, the t-test was performed using a
Satterthwaite approximation for the variance.
The t-tests were performed in SAS® v 9.2, using the PROC
TEST procedure.
2.2 CWAs
Persistence testing for CWAs was used to establish an
environmental baseline condition for subsequent liquid and
furnigant decontamination investigations. Based on the results
from the TICs persistence investigation, the impact of varying air
velocity by use of fans blowing over the coupons for CWAs was
not investigated here.
2.2.1 Test Chamber
The test chamber consisted of a specially fabricated
polycarbonate (Lexan®) chamber inside a stainless steel cage
(with double security locks. The coupons were placed on
removable custom built shelves made of 26 gauge cold rolled
steel inside the chamber. The inner chamber had dimensions
of 26 x 29 x 27 cm. or 20.4 L. A new polycarbonate chamber
and shelves were used for each CWA tested. An MFC (Sierra
Instruments) was used to adjust and maintain an air exchange
rate of one change h"1 in the chamber with laboratory air. Air
removed from the test chamber was vented through a carbon
scrubber column before being discharged into the laboratory
fume hood where the chamber was housed.
The temperature and humidity in the chamber were monitored
continuously (at 30 min intervals) by the HVAC system. The
HVAC readings were verified twice daily using a calibrated
NIST-traceable thermometer/hygrometer (VWR) with accuracy
of ± 1 °C for temperature and ±5% for RH. All of the readings
taken in the laboratory indicated that the temperature and RH
were constant throughout the test periods.
At the conclusion of tests, the chambers were decontaminated and
decommissioned according to U.S. Army regulation (AR50-6)
and BBRC standard operating procedures.14'7"111
2.2.2 Building Materials
The building materials that were spiked with CWAs to assess
analytical recovery and persistence are listed in Table 2-8; these
materials included porous, adsorptive, and nonporous surface
types. Test coupons were cut to the sizes indicated in Table 2-8
from larger pieces of stock material.
2.2.3 CWAs and SRSs
The source, lot number, and purity of the CWAs and SRS used
for the recovery experiments and persistence tests are listed in
Table 2-9.
Polymethyl methacrylate was added, 5% on a weight:volume
basis, as a thickening agent for GD. Typically, 5 mL of thickened
GD was prepared in a batch.
-------
Table 2-8. Building Material Test Coupon Characteristics for CWA Tests
Material
Decorative
laminate
Industrial-grade
carpet
Galvanized
metal ductwork
Ceiling tile'1
Lot or Batch
Grade 10, nominal thickness
1.2 mm, matte white finish
Style #M7978, color #910; Carpet
Corp of America, Rome, GA
Industry HVAC standard 24
gauge galvanized steel; Adept
Products Inc. West Jefferson, OH
Armstrong 954, Classic Fine
Textured
Manufacturer/
Supplier Name
Solid Surface Design
Shaw Industries,
Incorporated
Accurate Fabrication
Armstrong
Approximate Coupon
Surface Size, L x W, cm
(Surface area)
6.5 x 1.5 (9.75 cm2)
6.5 x 1.5 (9.75 cm2)
6.5 x 1.5 (9.75 cm2)
6.5 x 1.5(9.75 cm2)
Material
Preparation
None
None
Clean with
acetone
None
1 Limited analytical method recovery tests conducted with ceiling tile and GB; no persistence tests conducted
due to significant losses
Table 2-9. Source of CWAs and SRSs
Chemical
Manufacturer/Supplier
Purity or Concentration
Concentration as Applied
Materials used for analytical methods tests and persistence tests
GB
GD
VX
TBP (SRS)
U.S. Army
U.S. Army
U.S. Army
Aldrich
96
94
70
99
Neat
95% neat
Neat
Neat
Standard Analytical Reference Material (SARM) used to confirm CWA purity
GB
GD
VX
US Army Medical Research Institute
of Chemical Defense
US Army Medical Research Institute
of Chemical Defense
US Army Medical Research Institute
of Chemical Defense
1 mg/mT.
1 nig/mL
1 mg/mT .
Not Applicable
-------
2.2.4 Application of CWAs to Test Coupons
For both analytical method recovery testing and persistence
testing, the coupons were spiked with the individual CWA to
achieve a loading of approximately 1 g m2. All building materials
were spiked with 1 uL of neat agent to deliver approximately 1
mg. A 50-uL repeating dispenser pipette (Hamilton) that delivers
50 equal volumes per syringe load was used to apply the CWA
to the test coupons. Because the syringe volume and dispensed
volume are not adjustable, it was not possible, for example, to
apply 1.4 uL of VX so as to offset the 70% purity. Concurrently
with the spikes to the test coupons, a 1-uL spike of each agent
was made directly into 10 mL of the extraction solvent and this
solution was analyzed to assess the amount of CWA applied to
the building materials. The amounts of CWAs applied to test
coupons are listed in Table 2-10.
Table 2-10. Spike Amounts of CWAs
Applied to Building Material Coupons
Chemical
GB
TGD
VX
Amount of CWA Applied
840 ng
840 ^g
580 ng
For the persistence tests, the coupon spiking was completed
within approximately 30 seconds, and coupons were loaded
directly into the test chamber after spiking. Drying time was
not needed since there was no solvent involved.
2.2.5 Extraction Method for CWAs
For extraction of building material coupons, the SRS was first
applied directly to the coupon as neat material; 1 uL of the SRS
delivered 1 mg. The coupon was then loaded into a 40-mL sample
extraction vial and a 10-mL aliquot of hexane containing the IS at
100 ug mL'1 was added. The vial was shaken briefly and then the
building material was allowed to stand in the solvent overnight
(~14-16 h) for passive extraction. Several times after addition
of the solvent, the vials were shaken to facilitate extraction and
dispersion.
2.2.6 Analysis Method for CWAs
Sample extracts were analyzed using gas chromatography with
flame photometric detection (GC/FPD) on an Agilent 6890
GC. Data collection, reduction, and analysis were performed
using Agilent Chemstation software, version B.02.05. The GC
conditions used for analyses of the three different CWAs are
listed in Table 2-11.
The GC retention times were monitored for each CWA, SRS, and
IS. Identification of an analyte included the correct GC retention
time ±0.02 min. The GC retention times are listed in Table
2-12. The quantification was performed using the IS method.
The IS was present at the same concentration in all samples and
standards. The 9-point calibration curve spanned the range of
0.24-190 ug ml/1. This concentration range is equivalent to 0.24
to 190% recovery of the spike amount used in recovery tests and
persistence tests.
Table 2-11. GC and FPD Conditions for CWA Analyses
Parameter
GC column for GBa
Condition
DB-5: 25 meter x 0.32 mm ID x 0.52 um film thickness; Agilent
Temp program for GB
55 °C (1 min); 55 °C-100 °C @. 10 °C/min; 100 °C-250 °C @ 25 °C/min (11.5 min rim
time)
GC column for TGDa
Rtx-5; 30 meter x 0.32 mm ID x 0.50 um film thickness; Restek
Temp program for TGD
40 °C (1 min); 40 °C-100 °C @ 10 °C/min; 100 °C-250 °C @ 30 °C/min (12 min run
time)
GC column for VX"
DB-5; 25 meter x 0.32 mm ID x 0.52 um film thickness; Agilent
55 °C (1 min): 55 °C-100 °C @ 10 °C/min; 100 °C-300 °C @, 25 °C/min (13.5 min run
time)
Temp program for VX
GC injection
1 uL splitless at 250 °C
Detector temp
250 °C
Hydrogen flow
70 mL min"1
Makeup gas flow
Nitrogen at 15 mL miir1
In all cases, helium was the carrier gas with a flow rate of 1.7 mL miir1.
-------
Table 2-12. GC Retention Times
for CWA Analyses
Chemical
GB
SRS
IS
TGD isomer 1
TGD isomer 2
SRS
IS
VX
SRS
IS
GC Retention Time, min
3.49
11.6
6.92
6.62
6.67
11.8
&92
6.16
5.74
2.05
2.2.7 Measurement of CWAs in Test Chamber Air
Measurement of the CWA concentration in the test chamber air
was performed by collection of an air sample onto a Carboxen
sorbent tube at denned intervals during the seven-day test period.
Aportion (100 mL min"1) of the vented chamber air (340 ml, mi IT
'), vented to maintain an air exchange rate of one exchange h"1,
was collected on the Carboxen sorbent tube. Sample collection
was 1 h in duration, with three sampling periods during Day
1, four sampling periods during Days 2-3, and four sampling
periods during Days 4-7. Following collection of the gas-phase
CWA. the Carboxen was removed from the sorbent tube and
placed in a 2-mL sample vial. A 1-mL aliquot of chloroform
containing the IS for quantification was added to the vial. The
sorbent and solvent were mixed vigorously on a vortex mixer
for 30 seconds; the sorbent was allowed to settle and a portion
of the extract was removed for analysis. The sorbent extract was
analyzed as described above for the coupon extracts.
2.2.8 Calculation of Percent Recovery and
Persistence
The calculations of percent recovery in analytical method test
experiments and calculations of persistence were carried out
using the same equations listed and described in Section 2.1.8
for the TICs.
In a manner identical to that described in Section 2.1.8, a
calculation of the distribution of the CWA between the known
compartments (air and coupons) and the unknown compartments
(walls, degradation products) was carried out for the first
sampling interval (first h of the persistence test). The CWA
recovered from the coupons was divided by the total amount
that was known to have been spiked onto the coupons to obtain
the analytical method (raw) recovery percentage from the
coupons. The CWA measured in the sampled air was divided by
the total amount that was known to have been spiked onto the
coupons to obtain the percentage in the air. The sum of these two
compartments was subtracted from 100% to obtain an estimate of
the amount of the originally spiked mass that was not accounted
for in the known compartments.
-------
-------
3.0
Quality Assurance/Quality Control
QA/quality control (QC) procedures were performed in
accordance with the TTEP Quality Management Plan (QMP)[I21
and the test/QA plan[3] for this investigation. QA/QC procedures
are summarized below.
3.1 PE Audit
A PE audit was conducted to assess the quality of die GC/MS
results obtained during these experiments. For the three TICs,
this PE audit was performed by diluting and analyzing standards
obtained from a secondary source. The secondary source
standards were diluted to 100 (ig ml/1 and analyzed using a
calibration curve constructed from the primary source standards.
The results of this analysis are given in Table 3-1. The target
tolerance was a percent difference less than 25%; results were
well within the target tolerance.
3.2 Technical Systems Audit
The Battelle QA Manager conducted a technical systems
audit (TSA) to ensure that the tests were being performed in
accordance with the test/QA plan[3] and QMP.[12] As part of the
audit, the Battelle QA Manager reviewed the reference sampling
and analysis methods used, compared actual test procedures with
those specified in the test/QA plan, and reviewed data acquisition
and handling procedures. No significant findings that might
impact the quality of the evaluation results were noted in this
audit. The records concerning the TSA are permanently stored
with the Battelle QA Manager.
3.3 Data Quality Audit
At least 10% of the data acquired during the evaluation was
audited. Battelle's QA Manager traced the data from the initial
acquisition through reduction to final reporting to ensure the
integrity of the reported results. In compliance with the test/QA
plan, all data calculations were checked.
3.4 QA/QC Reporting
Each assessment and audit was documented in accordance with
the test/QA plan[3] and QMP.[121 For this evaluation, no significant
findings were noted in any assessment or audit, and no follow-
up correction action was necessary. Copies of the TSA and
assessment report were distributed to the EPA QA Manager and
Battelle staff.
3.5 Deviations from Test/QA Plan
The persistence tests for the CWAs were conducted at RH values
of 12%-22%. rather than the 40% RH listed in the test/QA plan.
The RH was that of the laboratory air. To expedite work, it was
agreed that this would be acceptable for these tests but that
modifications would be made to achieve targeted RH values for
the decontamination tests. The persistence may have been slightly
lower with higher RH, so these results were taken as an upper
bound on persistence in planning for the decontamination tests.
In the persistence tests of TNT with the fans on, the coupons were
inadvertently spiked with 10% of the targeted spiked amount: 50
ug on the carpet and laminate coupons, rather than 500 ug, and
40 ug on the concrete, rather than 400 ug. Because of the general
agreement in results between the fans on and fans off conditions,
it appeared that this error did not compromise the utility of the
persistence data in planning for the decontamination tests.
The test/QA plan envisioned use of a 317-L test chamber. When
the coupon carousel and equipment would not fit into this sized
chamber, a 448-L chamber was substituted. This change did not
impact the investigation.
During the DMMP test with fans on, the humid air was
inadvertently turned off overnight and RH fell outside of the
target range for a total of about 20 h. The humidity level in the
test chamber was stabilized within 4 h of reactivating the RH
generator.
Appendix 1 (Version 3) specifies that the mass flow controller
used to control the air exchange rate in the test chamber will
be compared to a second NIST-traceable calibrated flow meter
before and after the experiment. The comparison of the mass
flow controller to a second NIST-traceable calibrated flow meter
was not performed during the CWA persistence investigatioa
Because the flow meters were within their calibration, the staff
inadvertently forgot to obtain a second calibrated meter to
compare the values. It is believed that there was no negative
impact on the study since the mass flow control meters were
within calibration and the calibration can be traced to NIST
standards.
Table 3-1. PE Audit Results
TIC
Malathion
DMMP
TNT
Sample ID
50866-100-19
50866-100-34
50866-38-16
Date of Audit
01/30/2006
02/05/2006
09/29/2005
Standard
Concentration
100 ugml/1
100 ug ml/1
100 ug ml/1
Measured Result
97.65 ug ml/1
84.06 ug ml/1
10 1.22 ugml/1
% Difference
-2.3
-15.9
L2
-------
3.6 Data Quality Indicators
Table 3-2 summarizes the data quality indicators that were
monitored and evaluated in accordance with the test/QA plan. GB
recovery from laminate was below the acceptance level specified
in the test/QA plan. However, this was believed to be due to high
volatility rather than inefficient extraction methods. Therefore,
GB on laminate was included in the persistence testing.
No CWA was recovered from laboratory blank coupons.
However, GB, TGD, and VX were all found to redeposit at
relatively high levels onto procedural blank coupons in the
test chamber. In many instances the recovery of CWA from
procedural blank coupons was above the acceptance level of
<10% of the mass recovered from test coupons that was specified
in the test/QA plan. These surprising results were accepted as
experimental findings.
Table 3-2. Measurements and Data Quality Indicators for Persistence Testing
Parameter
Measurement
Method
Data Quality Indicators
Corrective Action
(None except as specified)
Temperature
NIST-traceable
thermometer
Thermometer was compared against a calibrated
thermometer before and after experiment and
agreed within ±2 °C.
None.
Relative humidity
NIST-traceable
hygrometer
Hygrometer was compared against a calibrated
hygrometer before and after experiment, agreed
within ±10% except one check with bias of
-20%.
Subsequent hygrometer calibration check
performed at 40% RH, 22 °C found
instrument to read within 5% of the challenge
concentration.
Air exchange rate
in chamber
Mass flow
controller
NIST-traceable flow meter used for the air
exchange measurements was within calibration.
Before and after each experiment the meter was
compared to a second NIST-traceable calibrated
flow meter.
During the TICs persistence investigation, the
calibrated flow control meter was checked
16 times and all checks passed the acceptance
criterion.
During the CWAs persistence investigation,
a calibrated flow control meter was used,
but the flow meters were not compared
to a second flow meter before or after the
experiment. This deviation is described in
Section 3.5.
Agent on positive
control
Extraction/GC;
IS quantitation
48%-91% recovery of TICs from all materials;
within 40% to 120% recovery specified in the
test/QA plan.
45%-113% recovery of CWAfrom all
materials, except 23% recovery of GB from
laminate, within 40% to 120% recovery
specified in the test/QA plan.
All analytes and IS within 60%-140% of actual
value after correction for percent recovery.
Results from all coupons were within three
standard deviations of the mean—no outliers
were excluded.
All IS quantitation within 40%-120% specified.
Extraction of GB on laminate was rerun;
extraction efficiency of 23% for GB
on laminate was accepted for further
investigation because the low recovery was
believed to reflect evaporation rather than
issues with recovery methods.
Agent on
laboratory blank
or on procedural
blank
Extraction/GC,
IS quantitation
For all TICs, non-detect to 0.50% of spike
amount detected on blank coupons; lower than
limits of 1% and 10%, respectively, in test/QA
plan.
CWA all non-detects (<0.2%) of spike amount
on all laboratory blank coupons.
Some procedural blank coupons for GB. TGD,
and VX were observed to have more than 10%
of the amount of analy te compared to that
found on test coupons; this exceeded the level
of recovery from procedural blank coupons
specified in the test/QA plan.
The redepositiou of CWA onto procedural
blank coupons was accepted as an
unanticipated experimental result; findings
are included in Section 4.2.4.
-------
4.1 Results for TICs
4.1.1 Analytical Method: Recovery of TICs from
Building Materials
Prior to testing the persistence of TICs on test coupons of
building materials, the analytical method was tested to ascertain
accuracy (recovery) and precision (variability). The recoveries
of the individual TICs and their matched SRS compounds from
the different building materials are listed in Table 4-1. These are
raw recovery data calculated using Equation 1 in Section 2.1.8.
Because the TICs were being applied to each test coupon as a
spike in a solvent carrier, sufficient time was required to allow
the solvent to evaporate completely before testing extraction
efficiency. The time allowed for solvent to evaporate, 3-30 min,
was found to be excessive for DMMP as this TIC is considerably
more volatile than the other two. As a consequence, recoveries
of DMMP after 3-30 min evaporation times were less than 50%.
This test of analytical method recovery was repeated for DMMP
using one min evaporation times.
Table 4-1. Mean Percent Recovery of TICs and Matched SRSs from
Building Materials
4.0
Results and Discussion
The SRS was chosen so that its recovery in test coupon samples
would be similar to the recovery of the analyte of concern
and therefore informative about the method performance and
recovery of the analyte from the matrix when its level was not
known. As seen in Table 4-1, the recovery ratios of SRS/TIC
for malathion and DMMP (with short evaporation times) for
the different matrices were within 20% of each other (ratio of
0.80-1.20), which is slightly greater than what can be expected
when a labeled analog of an analyte is used as the SRS. The
recovery ratios for TNT and its SRS tended to be lower than
0.80, indicating that the method recovers the analyte more
efficiently than the SRS. Because of the differences in SRS and
TIC analytical method recoveries, the concentrations of analytes
in blind samples were corrected by relative recoveries of the SRS
and TIC, in addition to the normal correction by SRS recovery.
Recovery from Building Material, % ± SD
Material
Carpet (n = 9)
Laminate (n = 10)
Concrete (n = 10)
Evaporation
time, min
30
3
30
Carpet (n = 10)
Laminate (n = 9)
Concrete (n = 10)
30
3
30
Carpet (n = 10)
Laminate (n = 10)
Concrete (n =10)
1
1
1
Carpet (n = 9)
Laminate (n = 10)
Concrete (n = 10)
30
3
30
TIC
Malathion
84 ±7
80 ±3
51 ±4
DMMP
37 ±6
29 ±6
46 ±4
DMMP
72 ±4
71 ±9
48 ±4
TNT
91 ±6
16 i 16
48 ± 9
SRS
Fenchlorphos
95 ± 5
87 ±3
56 ±7
DEEP
78 ± 10
76 ±6
40 ±4
DEEP
86 ±4
82 ±3
52 ±4
TNB
69 ±7
62 ±8
32 ± 14
SRS/TIC
recovery ratio
1.13
1.09
1.11
2.10a
2.62a
0.87a
1.20
1.15
1.09
0.76
0.81
0.68
1 Ratio listed to show effect of evaporation time on relative losses of TIC and SRS; not used
in sample analyses.
-------
Recovery of the SRS during method development and during
persistence testing followed the same method described for the
TICs in Section 2.1. The recoveries of the SRSs in the analytical
method tests and the persistence tests were generally in good
agreement, with greater agreement for the SRS of malathion and
lesser agreement for the SRS of DMMP, presumably due to the
high volatility of the DEEP SRS used (compared to the generally
lower volatility of the malathion SRS). The similarities of these
SRS recoveries indicated that the method of analyte correction
based on SRS recovery is reasonable. The comparison of SRS
recoveries in the analytical method and persistence tests is given
in Table 4-2.
The approximate method detection limits (MDLs) for the TIC are
listed in Table 4-3. The MDL was estimated based on the signal
of the lowest level calibration standard (0.1 ug ml/1), the signal-
to-noise ratio for this concentration, and the peak area that can be
integrated reliably for any signal.
4.1.2 Persistence Over Time of TICs on
Building Materials
The persistence for each TIC on each of the building materials
was conducted simultaneously. The mean temperature and %
RH in the test chamber during the persistence testing is included
in Table 4-4. Details of the temperature and RH and air velocity
measurements are described in Section 4.1.6. One positive control
coupon was spiked and extracted immediately, along with a
laboratory blank coupon. A total of 45 test coupons (15 carpet test
coupons, 15 laminate test coupons, and 15 concrete test coupons)
were spiked with 500ug (400 ug for concrete) of the TIC, as
described in Section 2.1.4, and loaded into the test chamber. A
total of 5 spiked test coupons of each building material type were
removed after 24 h (one day), after an additional 48 h (three days
total), and after an additional 96 h (seven days total). These test
coupons were analyzed as described in Section 2. Each test was
conducted once with fans blowing air over the coupons with a
linear velocity of 400 ft miff1 (fans on) and once with the fans
turned off (fans off). The percent recoveries of the spiked TICs
from each building material type at initiation (Day 0) and on
subsequent days (Day 1, Day 3. Day 7). with the fans on and fans
off, were calculated as described in Section 2.1.8, using Equation
3, and are listed in Table 4-4. The spike recovery assumes spike
amounts as listed in Table 2-3. Spiked amounts were not checked
against an independent spike check samples as the Day 0 samples
were assumed to fulfill that role.
The between-trial variability in Day 0 recoveries (e.g., fans-on
and fans-off Day 0 recovery of malathion from carpet) had a
mean of 7.8% with a SD of 0.08% and ranged from <1% to 24%.
These results exclude Day 0 for TNT on concrete because of the
difference in mass spiked onto the coupons on those two days.
Table 4-2. Comparison of Mean Percent SRS Recoveries by
Building Material for Analytical Method Recovery Tests and
Persistence Tests
SRS (matched TIC)
Material
Fenchlorphos (Malathion)
DEEP (DMMP)
TNB (TNT)
Carpet
Laminate
Concrete
Carpet
Laminate
Concrete
Carpet
Laminate
Concrete
Mean SRS Recovery, % ± SD
Method test
(n=9 or 10)
95 ±5
87 ±3
56 ±7
86 ±4
82 ±3
52 ±4
69 ±7
62 ±8
32 ±14
Persistence test
(n=32)
97 ±9
85 ±12
52 ±14
74 ±5
66 ±6
56 ±13
58 ±16
71 ±13
25 ±13
Table 4-3. MDLs for TICs
MDL
In solution
On coupon
Malathion
0.01 ug ml/1
0.05 ug
DMMP
0.01 ugmL-'
0.05 ug
TNT
0.025 ug ml/1
0.125ug
-------
Table 4-4. Mean Recovery of TICs from Building Materials Under
Environmental Conditions
Time
Day 0 (n=l)
Day 1 (n=5)
Day 3 (n=5)
Day 7 (n=5)
Mean TIC Remaining on Building Material as Percent of Expected Spike Amount, % ± SDa
Malathion
Carpet
Fans on
25 °C, 38%RH
115
104 ±8
102 ±2
91 ±4
Fans off
24 °C, 41%RH
112
115 ± 3
105 ±3
94±3
Laminate
Fans on
25 °C, 38% RH
101
101 ± 9
76 ±11
33 ± 8
Fans off
24 °C, 41%RH
119
115±4
103 ±7
85±4
Concrete
Fans on
25 °C, 38%RH
63
24 ±8
12 ±8
5±3
Fans off
24 °C, 41% RH
103
48 ± 10
17 ±11
7± 4
DMMP
Time
Day 0 (n=l)
Day 1 (n=5)
Day 3 (n=5)
Day 7 (n=5)
Time
Day 0 (n=l)
Day 1 (n=5)
Day 3 (n=5)
Day 7 (n=5)
Carpet
Fans on
25 °C, 36% RH
110
23 ±5
12 ±2
7±3
Fans off
24 °C, 42% RH
112
18 ±3
13 ±2
8±2
Laminate
Fans on
25 °C, 36% RH
S9
0.7 ±0.2
0.6 ± 0.3
0.6 ± 0.3
Fans off
24 °C, 42% RH
71
0.3 ±0.3
0.4 ±0.1
0.2 ±0.2
Concrete
Fans on
25 °C, 36% RH
ii
102 ± 22
58 ±20
53 ± 8
Fans off
24 °C, 42% RH
74
78 ±5
65 ±3
74 ±4
TNT
Carpet
Fans onb
25 °C, 37% RH
129
121 ± 11
126 ±21
114 ±16
Fans off
25 °C, 39%RH
101
81 ±7
85 ±8
62 ±8
Laminate
Fans onb
25 °C, 37% RH
91
40 ±5
16 ±7
11±7
Fans off
25 °C, 39%RH
100
69 ± 10
68 ±17
45 ±13
Concrete
Fans onb
25 °C, 37%RH
5
8± 3
12± 4
21 ±14
Fans off
25 °C, 39% RH
53
43 ± 10
45 ±11
30± 5
a Mean recovery corrected by sample SRS mean recovery and by ratio of SRS to TIC recovery.
b TNT inadvertently spiked with 10% of die planned amount.
-------
Graphical representation of the spike recovery trends listed above
for malathion, DMMP, and TNT are shown in Figures 4-1, 4-2,
and 4-3. respectively. In the figures, fan off corresponds to the
condition in which the two fans above the carousel were off
during the test. Fan on corresponds to the test in which the two
fans were on throughout the duration of the experiment.
To assess persistence, the recovery data for Day 1,3, and 7 were
corrected by the amount measured in the extract of the Day 0
positive control sample. The TIC persistence on individual
coupons was calculated using Equation 4 in Section 2.1.8.
The mean persistence of the TICs over time is given in Table
4-5, along with notation of whether there was a statistically
Figure 4-1. Recovery of Malathion from Building
Materials (Mean conditions fans on: 25 °C and 38% RH;
fans off: 24 °C and 41% RH; error bars are 1 SD)
Recovery of malathion from carpet
140
120
100
HO
so
40
20
•
fan on
0246
Time since spiking, days
Recovery of malathion from laminate
110
120
100
aa
to
40
20
0
140
120
100
H
n
40
20
0
Time since spiking, days
Recovery of malathion from concrete
-9 -
fan on
•
\
2 4
Time since spiking, days
-------
Figure 4-2. Recovery of DMMP from Building Materials
(Mean conditions fans on: 25 °C and 36% RH; fans off:
24 °C and 42% RH; error bars are 1 SD)
140
120
100
SO
60
40
20
0
Recovery of DMMP from carpet
2 4
Time since spiking, days
Recovery of DMMP from laminate
120
100
so
Kl
40
M
0
-
•
\\
r \
\
\ .
-
fin on
i H
,
-
.
J 4
Time since spiking, days
140
120
100
H
50
--.o
20
o
Recovery of DMMP from concrete
0 2 A 6
Time since spiking, days
-------
140
120
100
n
so
40
20
o
Figure 4-3. Recovery of TNT from Building Materials
(Mean conditions fans on: 25 °C and 37% RH; fans
off: 25 °C and 39% RH; error bars are 1 SD)
Recovery of DMMP from carpet
fan on
Fan off
Time since spiking, days
Recovery of DMMP from laminate
120
too
80
60
40
20
o
•
fan on
fan riff
1*1
130
100
so
so
40
a
0
) 2 4 6
Time since spiking, days
Recovery of DMMP from concrete
•
fan on
2 4
Time since spiking, days
-------
significant reduction in persistence after seven days compared
to the persistence at Day 0 (Time 0); the t-test p-value for this
evaluation is listed. Table 4-5 also lists whether there was a
statistically significant difference between the persistence at
Day 7 for the conditions of "fans on" and "fans off" for each
combination of TIC and building material. Similarly, the p-value
for die t-test for this evaluation is listed.
As shown in Table 4-5, the fans-on condition had little or no
impact on the persistence of malathion on carpet and concrete.
However, in the case of malatliion on laminate, the fans-on
condition resulted in significant and substantial decrease in
persistence compared to the fans-off condition.
As indicated in the analytical method recovery tests, recovery of
malathion from concrete is about 50% even under relatively short
contact times with the matrix. This low recovery of malathion
from concrete is probably not due to volatilization losses, but
rather to hydrolysis or irreversible binding to the substrate.
Concrete is a highly basic substrate and also contains hydrated
inorganic complexes. Malatliion is readily hydrolyzed under
aqueous neutral, basic, and acidic conditions, so the water and/or
the basic sites in concrete could lead to degradation of malatliion
over time. In addition, given malathioif s low vapor pressure,
volatilization from concrete may be only a minor contribution
to analyte loss. In correcting each TIC recovery by the sample-
specific SRS recovery, we have assumed that the losses are
due only to analytical issues, e.g., extraction or concentration.
This may lead to an over-estimate of the amount of malatliion
remaining on the concrete, since the SRS does not account for
possible malatliion degradation.
In contrast, highly volatile DMMP does not persist on laminate
test coupons. This lack of persistence may be attributable to the
high vapor pressure and nonporosity of the coupon substrate
and low octanol:water partition coefficient of DMMP. On carpet
the DMMP is gradually lost from the coupons (down to 11%
by Day 3 and 7% by Day 7 with or without the fan on). Since
DMMP is not readily hydrolyzed, it appears that its persistence
on concrete is governed largely by vapor pressure; with air flow
over the surface to disperse vaporized material, the volatilization
rate increases. For laminate and carpet, air flow does not reduce
persistence. The DMMP is largely retained by the concrete;
persistence is reduced by air flow.
TNT is intermediate between malathion and DMMP in vapor
pressure and octanol:water partition coefficient, though more
similar to malathion than to DMMP. Indeed, TNT clearly persists
on carpet, but less on laminate surface. The greater persistence
of TNT on carpet with the fans on, compared with the fans off,
is difficult to explain or understand on the basis of these data.
Given the resistance of TNT to hydrolysis, it appears that its
persistence on concrete is governed by its low volatility rather
than hydrolysis to alternative products.
-------
Table 4-5. Mean Persistence of TICs on Building Materials over
Time as Percent of Day 0 Recovery
Duration
Day 1
Day 3
Day?
Reduction over time?
p-value
Difference with fans?
p-value
Duration
Day 1
Day 3
Day?
Reduction over time?
p-value
Difference with fans?
p-value
Duration
Day!
Day 3
Day?
Reduction over time?
p-value
Difference with fans?
p-value
Mean TIC Persistence on Building Material, % of Day 0 Recovery ± SD
Malathion
Carpet
Fans on
90 ±7
88 ± 1
79 ±4
Yes
p=0.0002
Fans off
103 ± 3
94 ±2
85 ±3
Yes
p=0.0003
Fans on=Lower persistence
p=0.0355
Laminate
Fans on
100 ±9
75 ± 10
32 ±8
Yes
pO.OOOl
Fans off
97 ±3
87 ±6
72 ±4
Yes
pO.OOOl
Fans on=Lower persistence
pO.OOOl
Concrete
Fans on
38 ± 13
19 ± 13
7±5
Yes
pO.OOOl
Fans off
46 ± 10
17±11
7±3
Yes
pO.OOOl
No difference in persistence
p=0.8131
IDMMP
Carpet
Fans on
21 ±4
11±1
7±3
Yes
pO.OOOl
Fans off
16 ±3
11±1
7±2
Yes
pO.OOOl
No difference in persistence
p=0.9495
Laminate
Fans on
0.8 ±0.2
0.7 ±0.3
0.6 ± 0.3
Yes
pO.OOOl
Fans off
0.4 ±0.4
0.5 ± 0.2
0.2 ±0.2
Yes
pO.OOOl
Fans on=Higher persistence
p=0.0445 •
Concrete
Fans on
104 ± 22
59 ± 20
54 ±8
Yes
p=0.0003
Fans off
106 ±6
87 ±4
99 ±6
No
p=0.8474
Fans on=Lower persistence
• pO.OOOl
TNT
Carpet
Fans ona'b
94 ±9
97 ± 17
89 ± 13
No
p=0.1143
Fans off
SI*,?
84 ±8
61 ±8
Yes
p=0.0005
Fans on=Higher persistence
p=0.0038
Laminate
Fans ona'b
43 ±5
17 ±7
12±8
Yes
pO.OOOl
Fans off
69 ±11
68 ±17
45 ±13
Yes
p=0.0006
Fans on=Lower persistence
p=0.0011
Concrete
Fans ona-b
17 ±6
24 ±9
43 ± 29
Yes
p=0.0120
Fan off
81 ±19
85 ± 20
57 ±9
Yes
p=0.0004
No difference in persistence
p=0.3254
a Due to anomalous data for Day 0 positive controls, the initial method recovery of TNT from concrete was
substituted for the positive control.
b TNT inadvertently spiked at 10% of planned spike amount.
-------
The statistical analysis provides evidence that persistence is
reduced after seven days for all agents, materials, and test
conditions with the exception of DMMP on concrete with the
fan off and TNT on carpet with the fan on. In the separate
comparison of whether mere is a difference in persistence for
Day 7 results between the tests done with fans on and fans off,
the results are mixed. For malathion, persistence with the fans
on is statistically significantly lower than with the fans off for
carpet and laminate, but no significant difference is detected
for concrete. For DMMP, the fans-on condition results in
significantly lower persistence on concrete, but not for carpet
or laminate. The laminate result actually shows a statistically
significantly greater persistence with the fans-on as compared
to fans-off, though both fans-on and fans-off conditions exhibit
very low average persistence (less than 1%). For TNT, the fans-
on condition yields significantly greater persistence than with
fans off on carpet. The reverse is true for laminate; the fans-on
condition provides lower persistence. The results for concrete
move in the same direction as the laminate result, but the
variability in observed persistence is so large that the difference
does not achieve statistical significance.
The statistical analysis results above are presented with the
assumption that statistical significance can be concluded
whenever the p-value is less than 0.05. This approach confers
95% confidence (i.e., no more than a 5% risk) that a significant
difference will not be concluded in error for a single comparison.
However, over the large number of comparisons made in
this evaluation, the cumulative chance of making at least one
erroneous conclusion of significance becomes larger than 5%. A
more conservative approach is to suppose that a maximum 5%
chance of error (i.e., minimum 95% confidence) is desired for
the collective set of all comparisons in the evaluation. A simple
approach to achieving this outcome is to employ a Bonferroni
correction to the results. Under this strategy, only p-values less
than 0.0019 would be considered statistically significant. The
general trend of reduced persistence after seven days would still
hold. However, the statistically significant differences between
fans on and fans off would be reduced. Only malathion and TNT
on laminate, and DMMP on concrete would exhibit statistically
significantly lower persistence with the fans on; none of the
test conditions would exhibit statistically significantly higher
persistence with the fans on.
Graphical representations of these trends for each TIC on the
three different types of building materials are shown in Figures
4-4, 4-5, and 4-6 for malathion, DMMP, and TNT, respectively.
Figure 4-4. Mean Persistence of Malathion on Building Materials as
Percentage of Time 0 Recoveries (Mean conditions fans on: 25 °C and
38% RH; fans off: 24 °C and 41% RH)
Persistence of Malathion on Carpet, Laminate, and Concrete
120
100
BO
60
40
20
o
A
O
A
carpet- Fan off
carpet- fan on
laminate- fan off
laminate- fan on
concrete- fan on
concrete- fan off
2 4
Time since spiking, days
-------
Figure 4-5. Persistence of DMMP on Building Materials as Percentage of
Time 0 Recoveries (Mean conditions fans on: 25 °C and 36% RH; fans off:
24 °C and 42% RH)
Persistence of DMMP on Carpet, Laminate, and Concrete
120
100
80
40
20
0
A
concrete- fan off
concrete- fan on
carpet- fun off
carpel- fen on
laminate- fan on
laminate-fan off
2 4
Time since spiking, days
6
Figure 4-6. Persistence of TNT on Building Materials as Percentage of
Time 0 Recoveries (Mean conditions fans on: 25 °C and 37% RH; fans
off: 25 °C and 39% RH)
Persistence of TNT on Carpet, Laminate, and Concrete
120
100
0-
carpei- fan an
carpal- fan off
concrete* fan off
laminate- fan off
concrete* fan on
laminate* fan on
246
Time since sptking, days
-------
4.1.3 Concentrations of TICs in Test Chamber Air
Real-time APCI MS/MS was used to monitor the air
concentration of each TIC in the chamber during the persistence
tests. Approximately 50% of the air that was vented from the
chamber to achieve 1 air exchange Ir1 (7.5 L/min) was directed
into the inlet of the APCI MS/MS instrument. Except for
once daily calibration of the instrument response (needed for
quantification), the MS/MS instrument monitored effluent from
the chamber continuously. The time-weighted average chamber
air concentrations of each TIC during the persistence tests
are listed in Table 4-6. The concentrations are listed as those
measured during the time when all 45 test coupons were in the
chamber (Day 1 of the test), during the next 48 h period when
30 test coupons were in the chamber (Day 2-3), and during the
following 96 h period when 15 test coupons were in the chamber
(Day 4-7).
After the completion of a seven-day persistence test, the
polycarbonate front panel was removed and all inner surfaces
(fiberglass) were wiped with acetone. Before reassembly, the
chamber and polycarbonate front panel were allowed to air
dry. Following reassembly, the chamber was purged with zero
air at least 12 h before the next persistence test was begun.
At the beginning of a persistence test, the background TIC
concentrations were measured in real-time with APCI-MS/MS
and were found to be quite low if not negligible.
Calculations based on APCI MS/MS results were used to
estimate the total amount of each TIC lost from the chamber due
to air exchange ventilation. This value, described as an average
ventilation loss (ug Ir1), is listed in Table 4-7 for these three time
periods.
The amount of a TIC removed from the chamber by volatilization
and subsequent ventilation due to maintenance of one air
exchange h"1 represented only a small percentage of the total
amount of that TIC present in the chamber. As discussed below in
Section 4.1.4, the amount of TIC removed from the chamber due
to ventilation was <5% of the amount estimated to be present in
the chamber.
Table 4-6. Air Concentrations of TICs During Persistence Tests
Average Air Concentration in Chamber, ug rtr3
Time (Coupons in chamber)
Day 1 (45 coupons)
Day 2-3 (30 coupons)
Day 4-7 (15 coupons)
Malathion
Fans on
2.4
1.6
0.54
Fans off
NT-
NT
NT
DMMP
Fans on
61
20
10
Fans off
61
15
5.1
TNT
Fans on
0.77
0.63
0.37
Fans off
0.84
1.0
0.93
aNT= not tested; instrument difficulties prevented monitoring during this test (see Appendix
Section A.2.3 for details).
Table 4-7. Amount of TIC Vented from Chamber by Air Exchange
(7.5 L/min)
Amount of TIC Vented, ug (average ug h-1)
Time (Coupons in test
chamber)
Day 1 (45 coupons)
Day 2-3 (30 coupons)
Day 4-7 (15 coupons)
Malathion
Fans on
23 (0.96)
37 (0.77)
26 (0.27)
Fans off
NT
NT
NT
DMMP
Fans on
840 (35)
320 (6.7)
390(4.1)
Fans off
1100 (46)
390(8.1)
250 (2.6)
TNT
Fans on
6.5 (0.27)
11 (0.23)
13(0.14)
Fans off
7.3 (0.30)
26 (0.54)
36 (0.38)
NT= not tested (see Appendix Section A.2.3 for details).
-------
4.1.4 Mass Balance of TICs
The estimates of the amount of each TIC removed from the
chamber due to ventilation compared with the spiked amounts on
die coupons and the measured amount remaining on die coupons
indicated a significant shortfall in accounting for the mass of
each TIC. Two possibilities exist for diis shortfall: analytes may
have been degraded to other species or the analyte may have
redistributed to odier surfaces in the chamber such as die walls,
platform, and fans. Degradation on concrete may be a reasonable
explanation for a TIC such as malathion, which is more prone to
hydrolysis, because concrete retains water and has basic sites. In
die majority of the cases, though, given die stability of the TICs
and die neutral nature of die substrate, it is possible diat much of
the unaccounted for mass of each TIC was adsorbed on (or in) die
walls of die chamber following initial volatilization. The interior
walls of die chamber were not sampled at die end of each test to
verify' this hypotiiesis. Five of the six chamber walls were made
of fiberglass, but the front wall was constructed of polycarbonate.
It is possible that this polymer would act as a sorbent for gas-
phase material.
Distribution of each TIC between the measured and known
compartments (coupons and air) and the unmeasured and
unknown compartments (walls, degradation products) are given
in Table 4-8.
The distribution of mass between known and measured
compartments (coupons and air) and unknown compartments
(degradation or wall losses) are shown graphically in Figures 4-7,
4-8, and 4-9 for rnalathion, DMMP, and TNT, respectively. The
total amount in die chamber decreased over time first because
five coupons of each building materials type were removed at
each interval and second because of losses due to degradation or
adsorption onto otiier compartments such as walls. Tests were not
conducted to ascertain die loss mechanisms.
Table 4-8. Estimate of Distribution of TICs Among Coupons and Vented Air
TIC
Malatliion
DMMP
TNT
Fans
on
off
on
off
on
off
Time period
Day 1
Day 2-3
Day 4-7
Day 1
Day 2-3
Day 4-7
Day 1
Day 2-3
Day 4-7
Day 1
Day 2-3
Day 4-7
Day 1
Day 2-3
Day 4-7
Dav 1
Day 2-3
Day 4-7
Distribution, % of Total
Coupons
79
64
42
84
7§
s»
36
21
18
34
29
31
54
48
48
76
79
54
Air
0.1
0.3
0.4
NT-
NT
NT
4
2
6
5
3
4
0.3
0.8
I;f
0.1
0.2
0.5
Mass Not Accounted for,
% of Total
Unknown
21
36
58
If"
3P;
42 b
60
77
76
60
68
66
46
51
5i
24
21
45
aNT= not tested; air concentration of malatliion not tested witii fans off.
bBased on assumption that air level is <1%.
-------
Figure 4-7. Accounting for Mass of Malathion
Malathion mass accounted for and unaccounted for
20-
15-
10-
on coupons and in air
unaccounted for mass
i liii
V ^/ \J Q
test interval and condition of fans in chamber
Figure 4-8. Accounting for Mass of DMMP
DMMP mass accounted for and unaccounted for
20
15 -
10 -
on coupons
unaccounted for mass
in air
J
~
"
test interval and condition of fans in chamber
-------
Figure 4-9. Accounting for Mass of TNT
TNT mass accounted for and unaccounted for
20
15
10-
on coupons and In air
unaccounted for mass
I
I
, v-
X'
, v-
,. ov
it'"
y-
o*1 o*1 o*1 oai
test interval and condition of fans in chamber
(Note: 10% of the intended spike level was added to the concrete coupons for the
test with the fans on, and thus the total amounts to be accounted for are lower in
this test.)
4.1.5 TICs on Building Material Blanks
The quantities of the TICs on the building material coupon
blanks, SD, and % of spike amount are listed in Table 4-9. The
limit of quantification (LOQ) of the analytical method is 0.1%
of the spike amount. The amount of contamination measured
on coupon blanks was in all cases at or below the LOQ of
the analytical method. The most probable explanation for
the small amount of TIC contamination measured on the blank
coupons is slight background contamination of the analytical
instrument, which manifested as coupon contamination. These
small background amounts are insignificant with respect to test
outcomes.
The blanks included the laboratory coupon blanks that were
not exposed to the laboratory fume hood where spiking was
performed and the procedural coupon blanks mat were held in the
laboratory fume hood and extracted at such time as the matched
test coupons were extracted. Because of the similarity in blank
levels on the laboratory blank coupons and the procedural blank
coupons, as well as the similarity in levels for coupons from
the tests with fans on or fans off, the data were averaged and
presented as a single value.
Table 4-9. Amount of TICs on Building Material Coupon Blanks
Amount on Coupon Blanks, ug ± SD (% of spike amount), n=10
Malathion
DMMP
TNT
Carpet
0.50 ±0.18 (0.10%)
0.12 ±0.05 (0.02%)
0.16 ±0.22 (0.03%)
Laminate
0.38 ± 0.22 (0.08%)
0.10 ±0.06 (0.02%)
ND. <0.04 (0.01%)a
Concrete
0.28 ±0.17 (0.07%)
0.12 ±0.07 (0.03%)
0.09 ± 0.09 (0.02%)
aND = not detected; less man the MDL.
-------
4.1.6 Environmental Conditions During
Persistence Tests
The air exchange rate through the test chamber was maintained
at one exchange h'1 throughout all testing by using MFCs to
set the total flow into the -450 L chamber at 7.5 L mirr1. The
temperature, RH, and air flow over the building material coupons
were carefully controlled and monitored during all trials. The data
for the environmental parameters are presented in Table 4-10.
As noted in Table 4-10, footnote b, during one test, the humid
air was inadvertently turned off overnight. Dehumidification
occurred immediately after Day 1 coupons were removed from
the chamber and the humidity generator was refilled with DI
water. The test crew inadvertently forgot to restart the flow
through the humidity generator after refilling, so the chamber
humidity slowly dropped overnight. Humidification was restored
the next morning (after approximately 16 h) and RH quickly
came back up to target level of- 40%. The mean RH over
seven days was 36%. There were no significant and consistent
differences observed between fans-on and fans-off recoveries
(shown in Table 4-5) that would suggest that the period of low
humidity had an impact on the results.
When the anemometers were positioned 1-2 nun above the
carousel platform, die air velocities were approximately 400 ft
min'1. However, two problems were noted with this configuration:
• The anemometers were easily disturbed when removing the
coupons from the chamber.
• The measured variability in wind speed artificially increased
when only a few coupons, 15 or less, remained in the test
chamber.
By repositioning the anemometers to an approximate height
of 8 mm above the carousel, the probes were less likely to
be disturbed when coupons were removed from the chamber.
A subsequent velocity mapping study was performed at the
8 nun. The study confirmed that the anemometers registered
air velocities of 130-180 ft min"1 while the air velocity over
the coupons remained at ~ 400 ft miff1. The variability in the
measured air velocity was not significantly decreased by the
relocation.
For the persistence tests with no air actively directed over the
coupons, the anemometers detected a small but measurable air
velocity. Air was moving inside the test chamber due to the action
of the mixing fan that always operated to ensure a homogeneous
test chamber atmosphere. The typical background air velocity
was ~20 ft min'1, or only 5% of the target air velocity with the
fans activated.
Table 4-10. Temperature, RH, and Air Velocity for Persistence Tests
(Average ± SD)
Test
Malathion - fans on
Malathion - fans off
DMMP - fans on
DMMP - fans off
TNT - fans on
TNT - fans off
Temperature, °C
25.0 ±0.9
23. 7 ±2. 3
25.0 ±1.8
24.0 ± 2.4
25.3 ± 1.7
24.6 ±1.6
%RH
37.8 ±3.5
40.5 ±3.9
36.1±24b
41. 7 ±5.9
37.4 ±3.6
38.9 ±2.9
Air Velocity, ft min *
Anemometer 1
356 ± T
26 ±9"
154 ±7"
21±llc
138 ±5C
20 ±8°
Anemometer 2
428 ± T
20 ±3"
177 ± 6"
23 ± 6C
133 ±5C
23 ±7°
a Anemometers positioned 1-2 nun above the carousel stage.
bHumid air inadvertently turned off overnight, causing mean RH to drop and variability to
increase.
c Anemometers moved to 8 mm above carousel stage; with anemometers in this position a
reading of 130 -180 ft min'1 indicates an air velocity 1-2 mm above the carousel stage and
over the coupons of about 400 ft min'1.
-------
4.2 Results for CWAs
4.2.1 Analytical Method: Recovery of CWAs from
Building Materials
As described in Section 4.1.1, the analytical method was first
tested to ascertain accuracy and precision. Given the results
for DMMP from TICs testing, alternate building materials
(galvanized metal ductwork and ceiling tile) were evaluated for
use with the CWAs in order to get adequate persistence with
highly volatile GB. Galvanized metal was selected for use in
place of concrete for the CWA persistence testing. The recoveries
of the individual CWAs and the associated SRS from the different
building materials are shown in Table 4-11. Since there was no
solvent carrier for the application of CWAs, drying time was not
an issue. However, the length of time between application of
agent and initiation of extraction was found to be a significant
factor in recovery due to the higher volatility of GB in particular.
The recovery was tested initially with the 1-7-min hold times
between spiking and extraction, and was subsequently repeated
for several of the materials with 0.5-min hold times. As shown
in Table 4-11, recovery of GB from ductwork was virtually
100% with a 0.5-min hold time but dropped to about 50% with a
7-min hold time. Recovery of GB from the nonporous laminate
surface was about 25% after 0.5 min and dropped to less than
10% after 1 nun. The recovery from the ceiling tile with a 0.5-
min was approximately 30% from either the painted front side
or the unpainted back side. Given the high volatility of GB,
these recovery data indicated that the analytical losses were
probably due to volatilization from the surface before extraction
could be initiated, rather than to conventional analytical losses.
It appeared that GB was not sufficiently persistent on laminate.
metal ductwork, or ceiling tile to be useful for investigations of
decontamination technologies; therefore, extensive persistence
testing was not performed with these building materials.
Recoveries of TGD and VX were essentially 100% from all
matrices with hold times as much as 5 min between spiking and
extraction.
Due to the limited number of potential compounds available
to use as SRS compounds, and the lengthy experience of the
analysis group with the existing method, there was no attempt
Table 4-11. Mean Recovery of CWAs and SRSs from Building
Materials as Percent of Expected Spike
Mean Recovery from Building Material, % ± SD
Material
Hold
time, mina
Laminate (n = 7)
Ductwork (n = 7)
Ceiling tile, front (n=7)
Ceiling tile, back (n=7)
0.5
0.5
0.5
0.5
Carpet (n = 7)
Laminate (n = 7)
Ductwork (n = 7)
7
1
7
Carpet (n = 7)
Laminate (n = 7)
Ductwork (n = 7)
|
5
5
Carpet (n = 7)
Laminate (n = 7)
Ductwork (n = 7)
1
5
5
CWA
GB
23 ± 25
113 ±52
32 ± 14
32 ±9
GB
91 ±12
7± 11
45 ±18
TGD
88 ±18
97 ± 8
98 ±11
VX
113 ±9
107 ± 6
110 ±6
SRS
TBP
108 ± 5
102 ± 3
110 ± 16
88 ±22
TBP
87 ±14
81 ± 16
76 ± 13
TBP
98 ±11
89 ± 9
88 ±10
TBP
103 ±21
93 ±14
94 ±15
SRS/CWA
recovery ratiob
4.7
0.90
3.4
2.8
0.96
11.6
1.7
1.11
0.92
0.90
SJ1
0.87
0.85
"Length of time between spiking and extraction.
bRecovery of SRS/recovery of CWA; used to adjust for slight differences in
extraction and analytical recovery between each CWA and the SRS; combined with
the SRS recovery correction in every sample to adjust for analytical losses.
-------
made to select a specifically matched SRS for each CWA. Rather,
die same SRS was used for all analyses. In general, the data
indicate that TGD and VX are recovered slighdy more efficiendy
than the SRS from the building materials. For materials where
GB was fully recovered, it appears that recovery of GB is also
slightly greater than die recovery of the SRS.
The recoveries of the SRS in die analytical method tests and
the persistence tests were generally in good agreement. The
recoveries of die SRS were higher hi die persistence tests
compared with the method recovery tests, but tiiese differences
are not statistically significant. The comparison between SRS
recoveries in the two sets of tests is given in Table 4-12.
The MDLs for the CWAs are listed in Table 4-13. Note that die
MDL on die coupon takes into account the 10-mL final volume of
extracts from a coupon.
Table 4-12. Comparison of Mean SRS Recoveries by Building
Material for Method Recovery Tests and Persistence Tests
SRS (CWA)
TBP (GB)
TBP (TGD)
TBP(VX)
TBP (TGD)
TBP (VX)
TBP (TGD)
TBP(VX)
Material
Carpet
Carpet
Carpet
Laminate
Laminate
Ductwork
Ductwork
Mean SRS Recovery, % ± SD
Method test (n=7)
87 ±14
98 ±11
103 ± 21
89 ±9
93 ±14
88 ±10
94 ±15
Persistence test (n=30)
93 ± 15
103 ± 14
124 ±7
97 ±9
114±10
99 ±12
116 ± 11
Table 4-13. MDLs for CWAs
MDL
In solution
On coupon
GB
0.04 ug/mL
0.4 ug
TGD
0.08 ug/mL
0.8 ug
VX
0.09 ug/mL
0.9 ug
4.2.2 Persistence Over Time of CWAs
on Building Materials
The low recovery of GB from laminate, ductwork, and ceiling tile
was attributed to high volatility of GB rather tiian to incomplete
extraction from the matrix. Because of die low recovery of GB
from laminate (7% after 1 niin), from ductwork (45% after 7
min), and from ceiling tile (32% after 0.5 min), comprehensive
persistence testing using tiiese building materials was not
attempted. Rather, some limited data were gadiered on the
recovery of GB from laminate and ductwork coupons over a
30-uiin interval. These limited recovery data and the data from
application of die controlled persistence tests of GB. TGD, and
VX on otiier building materials are shown as a part of Table 4-14.
The testing of the persistence of each CWA was conducted
simultaneously for all of die building materials selected for
that compound. The protocol included analysis of five positive
control coupons, as opposed to the one positive control coupon
used in the TIC persistence tests. There was, in addition, one
spike control where a 1-uL aliquot of neat agent (identical to the
volume applied to a building material coupon) was added directly
to a vial containing 10 mL of the extraction solvent. The analysis
of this spike control was used to determine the absolute amount
of the CWA applied to all the coupons spiked at diat time for a
test.
For TGD and VX, a total of 90 test coupons were spiked and
loaded into die test chamber. For GB (because only carpet was
tested in the chamber), there were 30 test coupons spiked and
loaded into die test chamber. The recoveries of the CWAs in
these persistence tests are listed in Table 4-14. The percent
recoveries of die spiked CWA from each building material type
at initiation (Day 0) and at subsequent times were calculated
as described in Section 2.1.8, using Equation 3. GB evaporates
from die nonporous surfaces tested in less than 15 min and
evaporates from carpeting in approximately seven days. TGD is
nondetectable, or nearly so, on all three matrices in seven days;
recoverable VX also decreases by seven days.
-------
Table 4-14. Mean Recovery of CWAs from Building Materials
Mean CWA Remaining on Building Material Test Coupons
as Percent of Expected Spike, % ± SD
Sampling Time
Day 0, 0 h (n=5)
Day 0, 1 h (n=5)
Day 0, 4 h (n=5)
Day 1 (n=5)
Day 3 (n=5)
Day 7 (n=5)
Sampling Time
Day 0, 0 h (n=5)
Day 0, 1 h (n=5)
Day 0, 4 h (n=5)
Day 1 (n=5)
Day 3 (n=5)
Day 7 (n=5)
Sampling Time
Day 0, 0 h (n=5)
Day 0, 1 h (n=5)
Day 0, 4 h (n=5)
Day 1 (n=5)
Day 3 (n=5)
Day 7 (n=5)
GB
Carpet
76 ±5
14 ±3
7±3
2.5 ±2.0
1.5 ±0.9
0.3 ±0.4
Laminate8
55±7(n=2) 0.5 min
NDb (n=2) 5 min
ND (n=2) 15 min
ND (n=2) 30 min
Ductwork3
85 (n=l) 0.5 min
34 ± 14 (n=2) 5 min
ND (n=2) 15 min
ND (n=2) 30 min
TGD
Carpet
74 ±14
62 ±35
32 ±2
9± 1
9±5
3 ± 0.2
Laminate
75 ±1
13 ± 3
0.21 ±0.01
0.08 ±0.03
ND
ND
Ductwork
69 ±6
28 ±8
0.96 ±0.16
0.63 ± 0.09
0.63 ±0.23
0.35 ± 0.03
m.
Carpet
72 ±17
74 ±6
73 ± 13
63 ±4
26 ±2
13 ± 0.6
Laminate
75 ±4
74 ±5
79 ±21
39 ±3
6±3
3 ±2
Ductwork
75 ± 3
73 ±4
88 ±18
67 ±4
41 ± 15
18 ±6
aLimited recovery data generated for highly volatile GB.
bND = not detected; less than MDL.
Graphical representations of the recovery trends above for
GB, TGD, and VX are shown in Figures 4-10, 4-11, and 4-12,
respectively. Note in particular that in the three graphs for GB
(Figure 4-10) that the time period for testing on carpet was
significantly different from the time period used for testing
persistence on laminate and metal ductwork surfaces, with the
testing on carpet being conducted over days and the testing on the
other two surfaces being conducted in minutes.
-------
Figure 4-10. Recovery of GB from Building Materials as
Percentage of Time 0 Recoveries (Mean conditions fans
off: 20 °C and 14% RH)
100
Recovery of GB from carpet
20
Z 4
Time since spiking, days
100
00
20
Recovery of GB from laminate
no air flow
10 15 20
Time since spiking, min
25
30
35
100
SO
60
40
20
Recovery of GB from ductwork
-•- noalrltow
10 15 20
Time since spiking, min
-------
Figure 4-11. Recovery of TGD from Building Materials as
Percentage of Time 0 Recoveries (Mean conditions fans off:
21 °C and 22% RH)
120
1CO
no
60
40
Recovery of TGD from carpet
no all flow
100
80
60
2 4
Time since spiking, days
Recovery of TGD from laminate
o
no ait How
100
80
60
40
20
2 4
Time since spiking, days
Recovery of TGD from ductwork
no air flow
Time since spiking, days
-------
Figure 4-12. Recovery of VX from Building Materials as
Percentage of Time 0 Recoveries (Mean conditions fans off:
21 °C and 12% RH)
100
ao
CO
40
20
0
Recovery of VX from carpet
2 4
Time since spiking, days
Recovery of VX from laminate
100
90
60
40
20
0
—*— no AH (low
Z 4
Time since spiking, days
Recovery of VX from ductwork
100
60
60
40
20
0
2 4
Time since spiking, days
-------
The recovery data were corrected by the recovery on the
Day 0 positive control coupons to determine persistence. The
persistence of the CWAs over time is given in Table 4-15.
Clearly, the volatility of these agents played a major role in the
amount that was retained on these building materials. In three
out of nine cases, no C WA was detected in the coupon extract at
the end of the test regimen; in four out of nine cases, the amount
remaining was less than 5% of the original spiked quantity; in
the remaining two cases (of nine) the amount remaining was less
than 25% of the original amount.
Graphical representations of these trends for each CWA on the
three types of building materials are shown in the three panels of
Figure 4-13 for GB, TGD, and VX.
Table 4-15. Persistence of CWAs on Building Materials
over Time as Percent of Day 0 Spike Recovery
CWA Persistence on Building Material Test Coupons, % ± SD
Duration
Ih
4h
Day 1
Day 3
Day 7
Duration
Ih
4h
Day 1
Day 3
Day?
Duration
Ih
4h
Day 1
Day 3
Day?
GB
Carpet
18±4
9±4
3.3 ±3
2.0 ±1
0.4 ±0.5
Laminatea
NDb, O.05 5 min
ND, <0.05 15 min
ND, O.05 30 min
Ductwork3
40 ± 16 5 min
ND, <0.05 15 min
ND, O.05 30 min
TGD
Carpet
84 ±47
43 ±3
12 ±1
12 ±7
4±0
Laminate
17 ±4
0.28 ±0.01
0.11 ±0.04
ND, <0.1
ND, <0.1
Ductwork
41 ±12
1.4 ±0.2
0.91 ±0.1
0.91 ±0.3
0.51 ±0.04
VX
Carpet
103 ±8
101 ±18
88 ±6
36 ±3
18 ±1
Laminate
99 ±7
105 ± 28
52 ±4
8±4
4±3
Ductwork
97 ±5
117 ±24
89 ±5
55 ± 20
24 ±8
aLimited persistence data for highly volatile GB.
bND = not detected; less man detection limit converted to percentage
of spike amount.
-------
Figure 4-13. Persistence of GB, TGD, and VX on Building
Materials Compared to Percentage of Spike Amount
Recovered at Time 0
Persistence of GB on Carpet
100
80
60
40
20
0
1
-
.
•
-
-e-carptt
-
-
0
2 4
Time since spiking, days
120
100
80
60
40
20
0
Persistence of TGD on Carpet, Laminate, and Ductwork
A
•-*-
caipct
ductwork
laminate
2 4
Time since spiking, days
140
120
100
80
CO
40
20
0
Persistence of VX on Carpet, Laminate, and Ductwork
2 4
Time since spiking, days
-------
4.2.3 Concentrations of CWAs in Test Chamber Air
The accuracy (recovery) and precision (reproducibility) of the
analysis methods for the sorbent-collected air samples of the
CWAs are listed in Table 4-16. These data were determined by
spiking a known amount of CWA onto the sorbent. The sorbent
was spiked with a known amount of C WA, and then clean air
was passed through the tube for 1 h. The tube was extracted and
extracts were analyzed and recoveries calculated.
Table 4-16. Method Recovery of CWAs
from Carboxen™ Sorbent
Recovery of CWA from Sorbent Tube, % ± SD (n=6)
GB
90 ±9
TGD
79 ±13
VX
61 ±13
The concentrations of the CWAs in the test chamber air at
the time intervals during persistence testing and the numbers
of coupons in the test chamber at each interval are listed in
Table 4-17.
The total amounts of each CWA vented from die test chamber,
due to air exchange, during each time interval of persistence
testing, and the conversion of this value to an hourly rate, are
listed in Table 4-18.
The amount of the CWA in the gas phase accounts for relatively
little of the total amount of the agent in the chamber at any given
time. Again, the high volatility of GB and TGD and the sorptive
nature of the polymeric chamber walls may together form a
plausible explanation for the fate of the CWAs. Distribution of
the CWA mass between the known compartments (coupons and
air) and the unknown compartments (walls, degradation products,
or other) for the first 1 h time period are listed in Table 4-19.
These distributions were calculated as described in Sections 2.1.8
and 2.2.8.
By the time the Day 7 samples were taken, the CWA (GB or
TGD) was not detected. The chamber was essentially free of
agent prior to the testing using each subsequent agent.
As shown in Table 4-19, the amount in the air accounts for 2%,
at most, of the total amount of the CWA in the test chamber.
As discussed below (see Section 4.2.4), a small amount of the
unaccounted for mass was found on the procedural blank coupons
that were held in the test chamber along with the spiked coupons.
Table 4-17. Air Concentration of CWAs During Persistence Tests
Time Period
Day 0, 1 h
Day 0, 2-4 h
Day 0, 5-24 h
Dav 2-3
Day 4-7
Number Coupons in Test Chamber
GBa
25
20
15
10
5
TGDorVXb
75
60
45
m
15
Average Air Concentration, ug rrr3
GB
16,000
850
20
5
ND, <4
TGD
60,000
16,700
1350
340
90
VX
NDC. <4
43
46
52
51
aTesting was performed only on carpet coupons.
bSimultaneous testing was performed on carpet, laminate, and ductwork coupons.
CND= not detected; less than identified MDL.
Table 4-18. Amount of CWA Vented from Chamber by Air Exchange
Time Period
Day 0, 1 h
Day 0, 2-4 h
Day 0, 5-24 h
Day 2-3
Day 4-7
CWA Vented, ug
GB
326
52
8
5
ND, <8
TGD
1224
1022
550
333
176
VX
NDa, O.08
2.6
19
51
100
CWA Vented, ug h '
GB
326
17
0.41
0.10
ND, <0.08
TGD
1224
340
28
7
2
VX
ND, 0.08
0.9
0.9
1.1
1.0
aND = not detected; less than identified MDL.
Table 4-19. Distribution of CWA Mass Between Known and
Unknown Compartments During First (Day 0, 1 h) Sampling Period
GB
TGD
VX
Distribution in Compartments, %
Coupons
14
34
74
Air
1
2
0
Unknown
85
64
26
-------
4.2.4 CWAs on Building Material Blanks
In contrast to the persistence tests for the TICs, the procedural
building material blank coupons for the CWAs persistence tests
were placed in the chamber during the persistence tests. The
blank building material coupon corresponding to Time 0, though,
was not placed in die chamber and is, therefore, a laboratory
matrix blank sample. The amounts of the CWAs measured on
these two different types of blank coupons, and those amounts as
a calculated percentage of the spike level applied to an individual
test coupon, are listed in Table 4-20 for the different agents and
building materials. The calculation and expression of the blank
level as a percentage of the amount that was spiked onto an
individual coupon was used to show that when detectable, levels
on blanks were quite low.
As shown in Table 4-20 for the Tune 0 laboratory blank coupons
(not placed in the test chamber), no CWA was detected. That
is, no background levels of CWA were detected. However.
the results for the building material blank coupons that were
placed in the test chamber indicate mat the CWAs redistribute
to adsorptive media in the chamber. The percentage of the spike
listed in Table 4-20 corresponds to the detected amount relative to
the spike amount applied to any single coupon. When the amount
found on the procedural blank coupons was normalized to the
total amount of the CWA in the chamber at a dine, approximately
0.4%-1.3% of the total mass was found on die procedural blanks.
Given the relatively small area of the coupons compared with die
overall area of die chamber, it seems plausible to assume diat the
majority of die unaccounted for mass may have been adsorbed
onto die chamber walls. In addition, die unaccounted for mass
may have become reaction degradation products. However,
neidier of tiiese possible explanations were tested.
Table 4-20. Amount of CWA on Laboratory and Procedural Blank Coupons
CWA
GB
TGD
VX
Time
0
Ih
4h
Day 1
Day 3
Day 7
0
Ih
4h
Day 1
Day 3
Day 7
0
Ih
4h
Day 1
Day 3
Day 7
Type of Coupon
Blank3
Lab
Procedural
Procedural
Procedural
Procedural
Procedural
Lab
Procedural
Procedural
Procedural
Procedural
Procedural
Lab
Procedural
Procedural
Procedural
Procedural
Procedural
Amount on Laboratory and Procedural
Blank Coupon, ug (% of single coupon spike amount)1'
Carpet
NDC (0.05%)
37 (4%)
9.0(1%)
1.8 (0.2%)
0.80(0.1%)
ND (<0.05%)
ND (<0. 1%)
170 (20%)
190 (23%)
53 (6%)
27 (3%)
15 (2%)
ND (<0.2%)
17 (3%)
17 (3%)
27 (5%)
44 (8%)
45 (7%)
Laminate
Ductwork
NTd
ND (<0. 1%)
ND(<0.1%)
ND(<0.1%)
ND(<0.1%)
ND(<0.1%)
ND(<0.1%)
ND (<0.2%)
19 (3%)
21 (4%)
NDa (<0.2%)
1.6 (0.3%)
2.2 (0.3%)
ND(<0.1%)
ND(<0.1%)
ND(<0.1%)
ND(<0.1%)
ND(<0.1%)
ND(<0.1%)
ND (<0.2%)
ND (<0.2%)
25 (4%)
NDa (<0.2%)
NDa (<0.2%)
NDa (<0.2%)
aLab blank = laboratory blank coupon, not spiked and not exposed to test chamber; procedural
blank = coupon not spiked, but adjacent to test coupons during spiking or placed in die test
chamber during persistence testing.
bBlank level expressed as a percentage of die amount that was spiked to an individual coupon; used
to show tiiat when detectable, blank levels were quite low.
°ND = not detected (MDL expressed as percentage of the spike level used on an individual coupon).
dNT = not tested.
-------
-------
For the three TICs and three CWAs tested, the amounts persisting
on the building materials decreased over dine when held at
environmental conditions typical of those that may be found
inside an office building or subway. As expected, the persistence
was significantly different for the different compounds in contact
with different building materials, and these differences may
be rationalized in terms of physicochemical properties such as
vapor pressure, hydrolysis rate, and solubility in organic-like
matrices (as indicated by the octanol:water partition coefficient).
For example, persistence of relatively nonvolatile malathion
and TNT on industrial carpet was approximately 61%-85%
over the seven-day period tested; in contrast, the persistence of
the higher volatility compounds (DMMP, GB, and TGD) was
7% on industrial carpet. For these highly volatile compounds,
persistence on the nonporous laminate surface or on the metal
ductwork was 0%-0.7%. VX is considered a nonvolatile agent
— it has the lowest vapor pressure of all of the conventional
CWAs. VX, with intennediate volatility between the highly
5.0
Summary
volatile compounds and the relatively nonvolatile compounds
like malathion, exhibited an intennediate persistence of 18% on
carpet and 25% on ductwork over the seven-day period tested.
The general trends in persistence on the different building
materials are summarized below in Table 5-1.
As shown in Table 5-1, TICs and CWAs on carpet generally
exhibited the most persistence; TICs and CWAs on laminate
generally exhibited the least persistence. For the persistence
testing with the TICs. which was determined with fans either
on or off in the test chamber, the persistence of lower volatility
malathion and TNT was greater when the fans were turned off.
For higher volatility DMMP, the persistence was approximately
the same whether fans were on or off.
The amounts of TICs or CWAs in the test chamber air accounted
for relatively little of the total mass of the applied compounds.
Distribution of the TICs and CWAs to other compartments, e.g.,
absorption to walls or conversion to degradation products, was
not determined.
Table 5-1. Trends in Persistence of TICs and CWAs
on Building Materials
Compound
DMMP
TNT
Malathion
GB
TGD
VX
Persistence on Building Material, Highest to
Lowest
Concrete > carpet > laminate
Carpet > concrete > laminate
Carpet > laminate » concrete
Carpet > laminate = metal ductwork
Carpet > metal ductwork > laminate
Metal ductwork > carpet > laminate
-------
Figure 5-1. Mean Persistence (as % of the Day 0
Recovery) of TICs and CWAs on Building Material
Coupons After Seven Days (Error bars are 1 SD)
Persistence of TICs after 7 days- with Fans off
120
100
-------
6.0
References
1. Boguski, T.K., Understanding Units of Measure, Environmental Science and Technology Briefs for Citizens
Issue 2 Center for Hazardous Substance Research, October 2006.
2. Groenewold, G., Williams J.M., Appelhans A.D., Gresham G.L., Olson I.E., Jeffery M.T., Rowland B., Hydrolysis
ofVXon concrete: rate of degradation by direct surface interrogation using an ion trap secondary ion mass
spectrometer. Environ. Sci. Tech., 2002. 36 (22): 4790^794.
3. Battelle, Test/QA Plan for the Systematic Evaluation of Technologies for Decontaminating Surfaces Inoculated
with Highly Hazardous Chemicals (Chemical Warfare Agents and TICs), Manipulation of Environmental
Conditions to Alter Persistence, Version 1 June 2005.
4. Battelle, SOP TTEP MECAP-004-00, "Spiking, Handling, Loading, and Removing Building Material Coupons
from the Exposure Chamber. " October 2005.
5. Method 8000 "Determinative Chromatographic Separations " as part ofSW-846 Third edition.
6. SMARTe.org, Understanding Units of Measure. September 2007.
7. Battelle, BBRC SOP 1-002 For the Storage, Dilution, and Transfer of Chemical Agents (CA) When CA
Concentration/Quantity Is Greater Than Research Dilute Solutions (RDS).
8. Battelle, SOP TTEP MECAP-OOI-00, "The Safe Handling of Quantities of2,4,6-Trintrotoluene (TNT)
for the Preparation and Storage of Standard Solutions. " August 2005.
9. Battelle, SOP TTEP MECAP-005-00, "Extraction of2,4,6-Trinitrotoluenefrom Building Material Coupons
and Preparation of Extracts for GC/MS Analysis. " February 2006.
10. Battelle, SOP TTEP MECAP-002-00, "Extraction ofMalathionfrom Building Material Coupons and
Preparation of Extracts for GC/AdS Analysis. " October 2005.
11. Batteile, SOP TTEP MECAP-003-00, "Extraction of Dimethyl Methylphoshonate (DMMP) from Building
Material Coupons and Preparation of Extracts for GC/MSAnalysis. " October 2005.
12. Battelle, Quality Management Plan (QMP)for the Technology Testing and Evaluation Program (TTEP);
Version 2. January 2006.
-------
-------
Appendix A
APCI MS/MS: Method Development and Real-Time
Monitoring for Gas-Phase TICs
During persistence testing, a PE-Sciex APCI-365 tandem MS
(APCI MS/MS) quantified in real time the concentration of TICs
present in the gas phase in the atmosphere of the test chamber.
The development of the APCI monitoring method, the procedures
to monitor TIC concentrations in real time including calibration
procedures and instrument performance and sensitivity checks,
and a brief synopsis of the data reduction methodology are
presented in this appendix. In addition, the results obtained for
real-time monitoring of the gas-phase TIC concentrations using
the APCI MS/MS technique are presented.
A.I Method Development
For each of the three TICs. the response of the APCI MS/MS was
first maximized by optimizing the potentials on the instrument's
various ion optics and the focus of the first and third quadruples
(Ql and Q3). The TICs were introduced into the MS ionization
source either directly as a vapor or were infused into the source
as a dilute aqueous solution. Separate sets of optimized MS
acquisition parameters were created for each TIC and are shown
in Table A-1.
An MS spectrum and an MS/MS spectrum were obtained under
the optimized conditions for each compound's appropriate
mass-to-charge ratio. See Table A-2 for the transitions that were
optimized and then monitored for real-time measurements. Also
shown in Table A-2 are the names and MS transitions of the IS
compounds used to correct for variations in MS response over
the course of a single seven-day experiment. This procedure is
explained in further detail below.
Table A-l. APCI MS/MS Acquisition File Settings
Acquisition File Parameters
Ion Mode
Nebulizer Gas Flow"
Curtain Gas Flow"
Collision Activated Dissociation Gas Flow3
Needle Current, kilovolts
Orifice Plate, volts
Ring Electrode, volts
Quad 0 Rod Offset, volts
Inter Quad 1 Len, volts
Stubbies, volts
Rod Offset 1, volts
Inter Quad 2. volts
Rod Offset 2, volts
Inter Quad 3, volts
Rod Off set 3, volts
Deflector, volts
Multiplier, volts
Malathion
Values
Positive
0
12
3
5
3
180
-4
•4
-10
-5
-15
-40
-55
-45
-300
2400
DMMP
Values
Positive
0
12
3
5
12
100
-5
-6
-8
-9
-15
-25
-55
-45
-300
2400
TNT
Values
Negative
0
12
3
-7
-20
-60
2.5
7
20
12
14
12.8
15
26
300
2600
aThe number corresponds to the dial setting. The relationship between the
setting and measured flow rates is not established.
dial
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Table A-2. Primary and Secondary Transitions for TICs
and APCI IS
Analyte
Malathion
Dimethyl methylphosphonate (DMMP)
Diisopropyl metliylphosphonate (DIMP) (IS)
2,4,6-Trinilrotoluene (TNT)
1,3,5-Trinitrobenzene (TNB) (IS)
Primary Ion
Transition
331 > 99
125.1 > 111
181 > 97
227 > 2 10
213 > 183
Secondary Ion
Transition
331>125
125.1>93
NA
227 > 193
NA
A.2 Real-Time Monitoring
Throughout each test, approximately 4 L mirr1 of air from the
test chamber was continuously withdrawn and introduced to the
APCI. The response of the APCI to a given TIC was averaged
and recorded over 30 time intervals. To ensure the proper
operation of the instrument, its mass calibration and response
sensitivity were periodically checked as described below.
A.2.1 External Calibration for Quantification
of TICs
Multipoint calibration curves, consisting of a minimum of six
points, were generated at the beginning and end of each seven-
day test period for each TIC. For calibration, known amounts
of a specific TIC were delivered to the APCI at a known rate;
the delivery method depended on the volatility of the TIC.
For malathion and TNT, dilute aqueous solutions of varying
concentration (typically from 0.1 to 10 ug ml/1) were prepared
and directed into the MS source through a custom-built vaporizer
at a known flow rate (typically 5 to 15 mL fr1) using a syringe
pump. As the air flow into the APCI MS/MS was constant,
variation of the aqueous concentration and liquid delivery rate
allowed for different gas-phase concentrations to be delivered
to the MS. For the higher volatility DMMP, the effluent from a
diffusion tube, containing neat chemical maintained at a constant
temperature in a permeation oven, was introduced to the MS
source in varying amounts through a heated transfer line. That is,
in order to generate a multipoint calibration curve, the amount
of DMMP delivered to the APCI inlet was adjusted by varying
the fraction of the oven air stream that was vented away from
the transfer line and replaced with DMMP-free makeup air.
Calibration was performed before and after each of the six TIC
experiments; the responses of the two curves were averaged
and the resultant mean response factor was used to quantify the
compound. All calibration curves generated had a correlation
coefficient of 0.985 or greater.
A.2.2 Mass Calibration Checks
A daily calibration of the mass scale of the APCI MS/MS was
performed during real-time monitoring in order to verify the
accuracy of the mass assignments of the MS/MS system. Mass
calibration was performed by disconnecting the instrument
from the test chamber and allowing compounds of known
mass to charge ratios (m/z) to be introduced to the MS source.
This procedure calibrated both mass resolving quadruples (Ql
and Q3) over the mass range of the selected TICs. The mass
accuracy was acceptable when within ±0.2 atomic mass units for
both Ql and Q3. If the mass calibration was unacceptable, the
instrument acquisition parameters were adjusted and the mass
calibration procedures repeated until the calibration was within
the acceptance criteria.
A.2.3 MS Response: Sensitivity Checks and
Tracking
To track and correct for short-term variation hi the response
of the MS/MS detector, sensitivity checks were performed.
For malathion, sensitivity checks were performed daily by
introduction of a known amount of malathion hi the gas phase
from a constant-temperature diffusion tube (for the fans-on
trial) and by infusion of malathion in an aqueous solution with
a vaporizer (for the fans-off trial). Although useful for tracking
the change in detector response, the concentration of these daily
checks was in general higher than the test chamber malathion
concentration. Following the completion of the checks, the
measured test chamber malathion concentration tended to
remain high and only gradually decreased to levels indicative
of the test chamber concentration observed prior to the checks.
This is possibly due to malathion carryover hi the sampling
lines or APCI inlet, as malathion is a semi-volatile compound.
Carry over was especially problematic during the fans-off trial
and caused such disturbance and variation in the measured
test chamber malathion concentration that the data for this run
were inconsistent and thus not reported. Therefore, the daily
sensitivity checks were discontinued in favor of simultaneous
real-time monitoring of an IS for the DMMP and TNT trials. To
generate a known constant IS gas concentration, the outlet of a
permeation oven containing the IS compound in a diffusion tube
was teed into the APCI sampling hue downstream from the test
chamber so that the IS was continually bled into the APCI inlet.
The IS response was monitored throughout the experiment to
assess the day-to-day sensitivity changes of the MS system and
to adjust the TIC concentration over the test period. Diisopropyl
metliylphosphonate (DIMP) was the IS used for DMMP and
1,3,5-trinitrobenzene (TNB) was the IS used for TNT. The
transitions monitored for these compounds are shown in
Table A-2.
-------
A.3 Data Reduction
The TIC concentration was calculated using the measured MS
response and the mean response ratio from the appropriate
calibration curves. Periods in the monitoring record where the
APCI had been disconnected to perform mass or MS sensitivity
checks were interpolated using a linear method with respect to
time. The DMMP and TNT concentrations were then multiplied
by a correction factor determined using the corresponding IS
response. The correction factor was calculated as the ratio of the
initial IS response (averaged over several hours at the beginning
of a trial) to the MS response to the IS at die time when the
correction was performed. TIC concentrations were plotted
with respect to time, and the mass measured over several time
intervals (Days 0 to 1, 1 to 3, 3 to 7, and total) were determined
by appropriately integrating the area under the concentration vs.
time curve.
A.4 Results from Air Sampling with APCI
MS/MS
The concentration of the TICs in the gas-phase in the test
chamber was monitored in real time during each of the six trials
using the APCI MS/MS. The primary objective of this real-time
monitoring was to investigate whether the APCI-365 could be
used to detect the TICs of interest in the gaseous atmosphere
of the test chamber. If the gaseous TICs could be detected,
additional objectives were to:
• Observe how the gas-phase concentration of the TICs
changes over the course of the seven-day test periods.
• Perform a mass balance calculation by quantifying the
amount of gas-phase TIC and comparing it to the amount
lost from the coupons as measured by extraction and
GC/MS.
The real-time monitoring results obtained during the TICs
persistence investigation are presented graphically in Figures A-l
through A-5. Designated in the figures are the dines at which die
coupons were removed from the test chamber on Days 1, 3. and
7. As described in Section A.2.3, a plot for maladiion with fans
off is not available because of difficulties witii die APCI MS/MS.
For all trials, the gas-phase TIC concentration in the test
chamber began to increase immediately when the coupons were
placed in the chamber at die start of a given trial. Furthermore,
in all cases the gas-phase concentrations were observed to
decrease over the duration of the trial. The results appear
consistent with volatilization of TICs from the coupons and
removal of coupons (spiked with TICs) from the test chamber
over the seven-day test periods.
The results obtained for malatliion, shown in Figure A-l, indicate
that the gas-phase concentrations of maladiion peaked at nearly
0.2 ppb shortly before the Day 1 coupons were removed from
the test chamber. With the fans on, die malathion concentration
decreased gradually from Day 1 through Day 7.
Among the tiiree TICs, die DMMP volatilized die most readily,
a fact tiiat was confirmed using real-time APCI MS/MS
monitoring. With the fans on, DMMP concentrations peaked at 62
ppb, but the maximum concentration reached was greater at 101
ppb with the fans off. Although die maximum concentration was
higher, die peak concentration was reached more quickly witii the
fans on: ~ 20 niin for fans on compared to ~ one h for fans off.
Thus real-time monitoring suggests tiiat increased air velocity
decreases DMMP persistence by accelerating volatilization of the
DMMP from the coupon surfaces.
Moreover, for both die fans-on and fans-off trials, DMMP
concentrations quickly decreased within hours after placing the
coupons in the test chamber and remained relatively low for the
remainder of the seven-day test period. This rapid rise in gas-
phase concentration of DMMP and subsequent steep decline is
in agreement with the GC/MS results for DMMP extracted from
coupons: during the first 24 h of the extraction experiments, all
of the DMMP was lost from the laminate and only 15%-20%
persisted on the carpet.
The TNT had die lowest gas-phase concentrations measured
during testing, witii a peak of-0.09 ppb shortly after the
commencement of the fans-on trial and concentrations
approaching 0.14 ppb during the second day of testing with
the fans off. The low gas-phase concentration witii the fans
on is most likely explained by the fact that only 10% of the
spike amount of TNT (0.1 g nr2) was applied to die coupons
as compared to those used in the fans-off trial (1 g nr2). Thus,
less TNT was present to volatilize from the coupon surfaces,
resulting in lower gas-phase concentrations. With die fans on,
gas-phase TNT concentrations rose rapidly upon placement of the
coupons into the test chamber, peaked within the first 24 h, and
then decreased over time. Witii the fans off, TNT concentrations
climbed throughout die first two days, peaked broadly during
Days 2 and 3, and gradually decreased tiirough Day 7. Without
air passing over the coupons, it appears tiiat TNT volatilization
was suppressed, as die persistence of TNT on the laminate
coupons indicates, causing TNT to accumulate in die gas phase
more slowly. The real-time monitoring results for TNT. shown
in Figures A-4 and A-5, support the assertion that increased air
velocity over the coupons generally decreases TNT persistence.
-------
Figure A-l. Real-Time Gas-phase Malathion Concentration in the
Test Chamber with the Fans On
0.25
.a
OH
a.
0.15
o
O
0.05
10/06/2005 10/07/2005 10/08/2005 10/09/2005 10/10/2005 10/11/2005 10/12/2005 10/13/2005 10/14/2005
Day
Figure A-2. Real-Time Gas-phase DMMP Concentration in the Test
Chamber with the Fans On
10/25/2005 10/26/2005 10/27/2005 10/28/2005 10/29/2005 10/30/2005 10/31/2005 11/01/2005 11/02/2005
-------
Figure A-3. Real-Time Gas-phase DMMP Concentration in the Test
Chamber with the Fans Off
11/04/2005 11/05/2005 11/06/2005 11/07/2005 11/08/2005 11/09/2005 11/10/2005 11/11/2005 11/12/2005
Day
Figure A-4. Real-Time Gas-phase TNT Concentration in the
Test Chamber with the Fans On
o.
0.00
11/16/2005 11/17/2005 11/18/2005 11/19/2005 11/20/2005 11/21/2005 11/22/2005 11/23/2005 11/24/2005
Day
-------
Figure A-5. Real-Time Gas-phase TNT Concentration in the
Test Chamber with the Fans Off
0.00
11/30/2005 12/01/2005 12/02/2005 12/03/2005 12/04/2005 12/05/2005 12/06/2005 12/07/2005 12/08/2005
-------
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