©EPA
www.epa.gov/nhsrc
technical BR
Evaluation of Nine Chemical-Based Technologies for Removal of
Radiological Contamination from Concrete Surfaces
Background
Because of its potential for deployment as a
terrorist weapon in an urban setting, the
radiological dispersion device (ROD), or "dirty
bomb," is a very real and significant danger.
Cesium-137 is one of many radioactive
isotopes with the potential to be employed in
an ROD. The National Response Framework,
the federal document that details how the
nation responds to such threats, identifies the
U.S. Environmental Protection Agency (EPA)
as a lead federal agency for decontamination
following such a radiological incident. This
response to a radiological incident could
include decontamination of buildings, equipment, and outdoor areas. In support of this role, the
EPA's National Homeland Security Research Center (NHSRC) evaluated the performance of
nine chemical-based decontamination technologies for their ability to remove Cesium-137 from
the surface of unpainted concrete. In addition, NHSRC evaluated various deployment-related
characteristics of the products.
The work, completed in 2011, is described in a series
of reports. These peer-reviewed reports provide
rigorous evaluations of the efficacy of nine
commercially-available surface cleaning technologies
of the type that could be employed to decontaminate
concrete surfaces following an ROD incident
releasing Cs-737.These reports, which can be
accessed via the NHSRC website
(www.epa.gov/nhsrc/), provide information that
emergency responders and their support personnel
can use in recommending or selecting appropriate
technologies for use during cleanup operations. This
information can also be used to assist federal, state,
and local emergency management authorities and
emergency response planners to prepare for
radiological homeland security events.
As part of U, S. EPA's Office of Research and
Development, the National Homeland Security Research
Center (NHSRC) provides products and expertise to
improve our nation's ability to respond to environmental
contamination caused by terrorist attacks on our nation's
water infrastructure, buildings and outdoor areas.
NHSRC conducts research related to:
• Detecting and containing contamination from
chemical, biological, and radiological agents
• Assessing and mitigating exposure to
contamination
• Understanding the health effects of
contamination
• Developing risk-based exposure advisories
• Decontaminating and disposing of
contaminated rn;
August 2011
This document does not constitute nor should be construed as an EPA endorsement of any particular
product, service, or technology.
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Results
A summary of the decontamination efficacy results is presented in Table 1. Unpainted
concrete coupons (standardized samples) were contaminated with Cs-137 and the
amount of contamination (radiological activity) deposited on each coupon was measured.
Each coupon was then treated with the decontamination technology under investigation
and the amount of contamination remaining was measured. The efficacy of the
decontamination technology is expressed both in terms of percent of contamination removed
(%R) and decontamination factor (DF). These efficacy measures are determined based on the
following relationships:
%R = (1-Af/A0) x 100%
DF = A0/Af
%R = percent of contamination removed
DF = decontamination factor
A0 = radiological activity from the surface of the coupon before decontamination
Af = radiological activity from the surface of the coupon after decontamination
For each technology, the product name in Table 1 is hyperlinked to the corresponding report in
the EPA's Science Inventory database. Operational-related characteristics are presented in
Table 2.
Table 1. Decontamination Efficacy
Product
Arqonne SuperGel
CBI DeconGel 1101
CBI DeconGel 1108
EAI Rad-Release I
EAI Rad-Release II
INTEK ND-75
INTEK ND-600
RDS Liquid
RDS Foam
Application Type
Liquid Spray/Vacuum
Strippable Coating
Strippable Coating
Liquid Spray/Rinse/Vacuum
Liquid Spray/Rinse/Vacuum
Liquid Spray/Rinse/Vacuum
Liquid Spray/Rinse/Vacuum
Liquid Spray/Wipe
Foam Spray/Wipe
Decontamination Efficacy
%R
73 + 5
49 + 7
67 + 9
71+13
85 + 2
47 + 6
52 + 12
53 + 7
51+8
DF
3.8 + 0.7
1.9 + 0.2
3.2 + 0.9
3.9 + 1.5
7.0 + 1.1
1.9 + 0.2
2.1+0.4
2.1+0.3
2.1+0.4
%R, percent of contamination removed; DF, decontamination factor
August 2011
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Table 2. Operational Characteristics
Parameter
Description
Decontamination Rate
• Arqonne SuperGel: Applied by trowel (paint scraper), scale up would require
spray equipment (similar to airless paint sprayer) or roller. Requires 1-2 hour
dwell time.
• DeconGel 1101 and 1108: Applied with paint brush, scale up would require
spray equipment or roller. Requires overnight drying before stripping dry
coating.
• EAI Rad-Release I and Rad-Release II: Applied using spray bottles in just
seconds. Rad-Release I is a single step process requiring approximately 30
minute dwell time. Rad-Release II is two-step process requiring a total of 60
minutes dwell time. Scale-up would require spray or foam generating
equipment, but dwell time would be the same.
• INTEK ND-75 and ND-600: Applied using spray bottles in just seconds. ND-75
requires three 15 minute application cycles. ND-600 requires three 30 minute
application cycles. Scale-up would require spray equipment, but dwell times
would be the same.
• RDS Liquid and Foam: Applied using spray/foam bottles in seconds. Requires
six cycles of application with two solutions and wiping with towels. Required 3-6
minutes for each 225 cm2 concrete coupon.
Applicability to irregular surfaces
All technologies were judged to be applicable to irregular surfaces, but those
requiring vacuum removal (Argonne, EAI, INTEK) may prove to be more difficult
depending on the surface and available vacuum attachments.
Skilled labor requirement
As evaluated, a brief training session is adequate. Scale up would require
somewhat more complex equipment and/or contractor support with corresponding
training requirements for equipment operation.
Utilities required
110v for vacuum; scale up would require more complex equipment such as
sprayers.
Extent of portability
Very portable; limited by need for utilities for vacuum and possible scaled-
application tools.
Setup time
Less than 15 minutes for all technologies as tested. Scaled up application would
require increased set-up time consistent with commercial spraying equipment.
Secondary waste management
towels was not reached due to the relative size of the coupons, Argonne
SuperGel: 5 L/ m2 gel waste collected in wet vacuum.
DeconGel 1101 and 1108: 319 g/m2 of dried coating and a volumetric waste
generation of 252 cm3/m2
EAI Rad-Release I and Rad-Release II: Approximately 1 L/m2 collected by the
wet vacuum
INTEK: Approximately 1 L/m2 collected by the wet vacuum
RDS Liquid and Foam: 4 L/m2 mostly collected by the towels used to wipe the
surface; 2000-3000 cm3 of towels used during this evaluation. The maximum
effective collection capacity of the therefore the total secondary waste volume
for a scaled up scenario is not a direct comparison. The capacity of the toweling
material was not evaluated.
August 2011
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Surface damage
Cost (material only; does not include
labor, equipment, or waste
management)
None of the technologies caused visible surface damage.
• Argonne SuperGel: approximately $2/m2
• DeconGel 1101 and 1 108: approximately $40/m2 (both 1101 and 1 108)
• EAI Rad-Release I and Rad-Release II: approximately $33-55/m2
• INTEK: approximately $1/m2 for ND-75 and $2/m2 for ND-600
• RDS Liquid and Foam: approximately $250/m2
Technology Evaluation Reports Referenced
Drake, J. 2011. Argonne National Laboratory Argonne SuperGel for Radiological
Decontamination. Washington, D.C.: U.S. Environmental Protection Agency. EPA/600/R-
11/081.
Drake, J. 2011. CBI Polymers DeconGe/® 1101 and 1108 for Radiological Decontamination.
Washington, D.C.: U.S. Environmental Protection Agency. EPA/600/R-11/084.
Drake, J. 2011. Environmental Alternatives, Inc. Rad-Release I and II for Radiological
Decontamination. Washington, D.C.: U.S. Environmental Protection Agency. EPA/600/R-
11/083.
Drake, J. 2011. INTEK Technologies ND-75 and ND-600 for Radiological Decontamination.
Washington, D.C.: U.S. Environmental Protection Agency. EPA/600/R-11/085.
Drake, J. 2011. Radiation Decontamination Solutions, LLC "Quick Decon" Solutions for
Radiological Decontamination. Washington, D.C.: U.S. Environmental Protection Agency.
EPA/600/R-11//086.
Contact Information
For more information, visit the NHSRC Web site at www.epa.gov/nhsrc
Technical Contact: John Drake (drake.john@epa.gov)
General Feedback/Questions: Kathy Nickel (nickel.kathv@epa.gov)
August 2011
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