THE ENVIRONMENTAL TECHNOLOGY VERIFICATION
PROGRAM
U.S. Environmental Protection Agency
~~ ' INTERNATIONAL
ET
ETV Joint Verification Statement
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TECHNOLOGY TYPE: DUST SUPPRESSANT
APPLICATION: CONTROL OF DUST ON UNPAVED ROADS
TECHNOLOGY NAME: DustGard
COMPANY: NORTH AMERICAN SALT COMPANY
ADDRESS: 9900 W. 109th STREET, STE 600
OVERLAND PARK, KS 66210
PHONE: 913-344-9391
WEB SITE: http://www.nasalt.com/
E-MAIL: kubalikb@compassminerals.com
The U.S. Environmental Protection Agency (EPA) has created the Environmental Technology
Verification (ETV) Program to facilitate the deployment of innovative or improved
environmental technologies through performance verification and dissemination of information.
The goal of the ETV Program is to further environmental protection by accelerating the
acceptance and use of improved and cost-effective technologies. ETV seeks to achieve this goal
by providing high-quality, peer-reviewed data on technology performance to those involved in
the design, distribution, financing, permitting, purchase, and use of environmental technologies.
ETV works in partnership with recognized standards and testing organizations; stakeholder
groups, which consist of buyers, vendor organizations, permitters, and other interested parties;
and with the full participation of individual technology developers. The program evaluates the
performance of innovative technologies by developing test plans that are responsive to the needs
of stakeholders, conducting field or laboratory tests (as appropriate), collecting and analyzing
data, and preparing peer-reviewed reports. All evaluations are conducted in accordance with
rigorous quality assurance (QA) protocols to ensure that data of known and adequate quality are
generated and that the results are defensible.
The Air Pollution Control Technology (APCT) Verification Center, a center under the ETV
Program, is operated by RTI International (RTI) in cooperation with EPA's National Risk
Management Research Laboratory. The APCT Center has evaluated the performance of a dust
suppressant product for control of dust on an unpaved road.
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ETV TEST DESCRIPTION
A field test program was designed by RTI and Midwest Research Institute (MRI) to evaluate the
performance of dust suppressant products. Five dust suppressants manufactured or distributed
by three firms were tested in this program. The field test for North American Salt Company's
DustGard was conducted at Fort Leonard Wood, Missouri (FLW). A July 2003 test/QA plan for
the field testing was developed and approved by EPA. The test/QA plan describes the
procedures and methods used for the tests. The July 2003 version of the test/QA plan was based
on an October 2002 version and a subsequent test/QA plan addendum (dated February 19, 2003).
The goal of each test was to measure the performance of the products relative to uncontrolled
sections of road over a 1-year period. Field testing was planned quarterly over a 1-year period;
however, some logistical difficulties related to winter weather and then maintenance activities on
the roads of interest arose, and the test/QA plan was revised (Rev 3) to address those issues. Test
periods occurred per the test/QA plan for three roughly 6-month periods. Two of those test
periods are summarized below and are considered most representative of product performance;
the third testing period occurred after unexpected road maintenance, and those data may be seen
in the verification report. The verification report also contains 90 percent confidence limits for
the data collected during all of the test periods. Emissions measurements were made for total
particulate (TP), particulate matter less than or equal to 10 micrometers (|_im) in aerodynamic
diameter (PMio), and for particulate matter less than or equal to 2.5 [im in aerodynamic diameter
(PM2.5).
The host facility for the field test program, FLW, is a U.S. Army base. The test site used
unpaved Roads P and PA in training area (TA) 236. Roads P and PA are the main access routes
to TA 236 and are traveled by truck convoys, as well as traffic into and out of TA 236.
DustGard was applied to test section E, located on Road PA; and test section F, located on Road
P, was left untreated as the experimental control. Section 3.1 of the verification report provides a
figure showing the test locations. Testing was conducted during October 2002, May 2003, and
October 2003.
Table 1 presents test conditions for key parameters that may affect the performance of dust
suppressants on unpaved roads.
Table 1. Test Conditions
Parameter
Initial application rate, 1/m2
Follow-up application rate, 1/m2
Time between application and testing, days
Precipitation during test week, cm
Precipitation during week before testing, cm
Precipitation between application and testing, total, cm
Soil moisture during test weeks, % — uncontrolled road
Soil moisture during test weeks, % — controlled road
Soil silt during test weeks, % — uncontrolled road
Soil silt during test weeks, % — controlled road
FLW,
October 2003
2.5
2.5
122
0.2
1.8
39
0.62-1.5
1.9-3.5
1.7-5.4
1.2-1.7
FLW,
May 2003
2.5
2.4
79
3.7
3.2
24
0.01-1.8
0.20-0.42
1.6-4.3
1.2-2.6
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The DustGard product was analyzed using an array of chemical and toxicity tests. The results of
these tests are included in the appendices to the verification report. A summary of the toxicity
data is presented in Table 2.
Table 2. Toxicity Test Results
Species
Ceriodaphnia dubia
Fathead minnow
Americamysis bahia
Acute LCSO
for survival
> 1,000 mg/L (48-hr)
>1,000 mg/L (96-hr)
> 1,000 mg/L (96-hr)
Chronic LCSO
for survival
> 1,000 mg/L (7-d)
> 1,000 mg/L (7-d)
> 1,000 mg/L (7-d)
Chronic ECSO
>1,000 mg/L (7-d),
reproduction
>1,000 mg/L (7-d),
growth
>1,000 mg/L (7-d), growth,
fecundity
d = day
EC50 = effective concentration which affects 50% of sample population
hr = hour
LC50 = lethal concentration which kills 50% of sample population
LOEC = lowest observed effective concentration
mg/L = milligrams per liter
NOEC = no observed effect concentration
VERIFIED TECHNOLOGY DESCRIPTION
This verification statement is applicable to North American Salt Company's DustGard, which is
a hygroscopic product made of magnesium chloride. The material safety data sheet (MSDS) for
DustGard is retained in the RTI project files and is available at http://www.nasalt.com/msds/
Magnesium%20Chloride%20(liquid).pdf [accessed July 2005].
VERIFICATION OF PERFORMANCE
The overall reduction in paniculate matter emissions achieved by the DustGard dust suppressant
compared to uncontrolled sections of road is shown in Table 3.
Table 2. Summary of Test Results
Test location and
period
FLW, October 2003
FLW, May 2003
Average control efficiency, %
TP
86
75
PM10
>90
88
PM25
59
58
Noted events
Rain events the day before test.3
Rain events the morning of test.b
a All test sections were wet from rain the previous day. The uncontrolled section was heavily
potholed and another section was used for the test. MRI used traffic to dry the road before
testing.
b Rainfall in the morning meant that the uncontrolled section of the road was wet and another
section was used for the test.
The APCT Center QA officer has reviewed the test results and quality control data and has
concluded that the data quality objectives given in the generic verification protocol and test/QA
plan have been attained. EPA and APCT Center QA staff have conducted technical assessments
at the test organization and of the data handling. These confirm that the ETV tests were
conducted in accordance with the EPA-approved test/QA plan.
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This verification statement verifies the effectiveness ofNorth American Salt Company's
DustGardto control dust on unpaved roads as described above. Extrapolation outside that range
should be done with caution and an understanding of the scientific principles that control the
performance of the technologies. This verification focused on emissions. Potential technology
users may obtain other types of performance information from the manufacturer.
In accordance with the generic verification protocol, this verification statement is valid,
commencing on the date below, indefinitely for application of North American Salt Company's
DustGardto control dust on unpaved roads.
Signed by Sally Gutierrez 9/25/2005 Signed by Andrew Trenholm 9/16/2005
Sally Gutierrez, Director Date Andrew R. Trenholm, Director Date
National Risk Management Research Air Pollution Control Technology
Laboratory Verification Center
Office of Research and Development
United States Environmental Protection
Agency
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