U.S. Environmental Protection Agency
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Immunoassay Test Kits for Atrazine
The U.S. EPA Environmental Technology Verification
(ETV) Program's Advanced Monitoring Systems
(AMS) Center, operated by Battelle under a cooperative
agreement with EPA, has verified the performance of
four immunoassay test kits for atrazine, three of which
provide quantitative results, while the fourth is a
qualitative method (Table I).1 These portable atrazine
test kits detect atrazine in various drinking and
environmental water matrices within hours. Results
from these test kits, followed by subsequent laboratory
confirmation, allow for quick corrective actions to
reduce atrazine levels if detected at levels of concern.
Conventional laboratory methods use gas
chromatography/mass spectrometry (GC/MS) to
measure atrazine in water. The verified test kits can
offer advantages over GC/MS in terms of time and cost
by providing a quick and cost-effective screening
method for atrazine levels.
Table 1 : Verified Immunoassay Test Kits for Atrazine in Water
Technology
Abraxis LLC
Atrazine ELISA Kit
Beacon Analytical Systems, Inc.
Atrazine Tube Kit
Silver Lake Research Corporation
Watersafe® Pesticide Kit
Strategic Diagnostics, Inc.
RaPID Assay® Kit
Type of Result
Quantitative
Quantitative
Qualitative
Quantitative
Technology Description and
Verification Testing
The verified test kits are based on colorimetric
immunoassay methods, which use specific antibodies to
detect and measure atrazine. The verification tests were
conducted in September 2003, on surface water
samples collected in South Carolina, ground water
samples from an aquifer on the Missouri River, and
chlorinated drinking water samples from a Battelle
laboratory in Duxbury, Massachusetts. ETV verified the
test kits in collaboration with the Texas Commission
on Environmental Quality (CEQ); EPA Office of
Prevention, Pesticides, and Toxic Substances; National
Oceanic and Atmospheric Administration (NOAA); and
University of Missouri-Rolla. The three test kits which
provided quantitative results were evaluated for
accuracy, precision and linearity. All four test kits were
evaluated for matrix interference, rate of false positives/
negatives, method detection limit, cross-reactivity, and
Atrazine and Its Regulatory
Background at a Glance
Atrazine, 2-chloro-4-(ethylamine)-6-
(isopropylamine)-s-triazine, is a commonly
used herbicide in the United States.
Annually, approximately 76.5 million pounds
of atrazine are used in formulations of
various products which are applied mainly to
agricultural crops such as corn and sorghum.
Following application, atrazine is absorbed
by plants or dispersed to the environment
through surface run-off, water seepage,
primary spray drift, and air dispersion and
precipitation.
In 1991, because of its frequent usage and
concerns about its health and environmental
effects, EPA established a drinking water
standard for atrazine of 3 parts per billion
(ppb). EPA is currently re-evaluating the
drinking water standard to determine if a
revision is needed. As part of the Interim
Reregistration Eligibility Decision (IRED) for
atrazine in 2003, EPA updated the human
health risk assessment for atrazine. The IRED
also required additional atrazine monitoring
for certain vulnerable public drinking water
systems and watersheds.
sample throughput. Table 2 lists the performance
of the four ETV-verified immunoassay test kits
for atrazine in water. Additional information is
available in the full verification reports which can
be found at http ://www.epa.gov/etv/verifications/
vcenter 1-28 .html.
A verified immunoassay test kit
The ETV Program operates largely as a public-private partnership through competitive cooperative agreements with non-profit research institutes. The
program provides objective quality-assured data on the performance of commercial-ready technologies. Verification does not imply product approval or
effectiveness. ETV does not endorse the purchase or sale of any products or services mentioned in this document.
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Table 2: Performance of Verified Test Kits for Atrazine in Water
Technology3
A
B
C
D"
Accuracy0
(percent recovery)
PT: 96 to 151%
Env: 102 to 156%
PT: 102 to 127%
Env: 100 to 140%
PT: 82 to 133%
Env: 83 to 171%
PT: 18 of 21
Env: 31 of 36
Precision0
(relative standard
deviation)
PT: 0.9 to 51.1%
Env: 2.6 to 16.7%
PT: 6.9 to 24.1%
Env: 3.5 to 15.2%
PT: 5.0 to 25.4%
Env: 3.9 to 22.8%
PT:7of7
Env: 9 of 12
Rate of False
Positives11
4 of 38
(11%)
4 of 38
(11%)
6 of 38
(16%)
8 of 56
(14%)
Rate of False
Negatives
none
none
none
none
Linearity
Slope
0.93
1.23
0.81
Not
evaluated
Intercept
0.26
-0.025
0.24
Not
evaluated
r
0.995
0.994
0.957
Not
evaluated
Sample Throughput'
50-60 samples in
1 .5 hours
50 samples in
1 .5 hours
30 samples in
1 hour
10 samples in
1/z hour
a Because the ETV Program does not compare technologies, the performance results shown in the table do not identify the technologies associated with
each result and are not in the same order listed in Table 1 .
b For this vendor, "accuracy" refers to the number of accurate results out of the total number of tests, and "precision" refers to the number of consistent
sets of replicate sample results out of total number of sets.
c PT = performance test sample; Env = environmental sample (overall range for all environmental samples); a result of 1 00% indicates perfect
accuracy relative to the nominal spike level atrazine concentration for PT samples and relative to the reference method results for Env samples. A
result of 0% indicates perfect precision.
d The test kits for the three quantitative technologies for false positive readings were compared to the lowest calibration standard of 0.1 ppb. For the
qualitative technology, the false positive readings were compared to a 3 ppb threshold level.
e Linearity was assessed using PT samples.
f Sample throughput includes calibration standards, quality control samples, and test samples.
Selected Outcomes of Verified Immunoassay Test Kits for Atrazine
Based on data from the IRED and other sources, the ETV Program estimates that approximately 3,900
community surface water systems, 940,000 private wells, and 10,000 watersheds are located in atrazine use
areas. With a 25% market penetration of the potential market, ETV estimates the following:
• The test kits would be used at 240,000 private water wells, 960 community surface water systems, and
2,500 watersheds to provide timely information on atrazine levels in water. These estimates include
systems and watersheds that require additional monitoring under the IRED.
• The information provided by the test kits can be used to identify whether mitigation is needed to reduce
atrazine levels. Ultimately, this information can assist in the reduction of atrazine exposure, with
associated environmental and human health benefits.
• The test kits would reduce monitoring costs and save time, since the immunoassay analyses used by the
verified technologies cost approximately five times less than GC/MS laboratory analyses and have
significantly shorter sample turnaround times (hours versus days). Based on model sampling programs at
960 community surface water systems and 2,500 watersheds, and assuming that 25% of the samples
required GC/MS confirmation, a national sampling cost savings of $5 million per year can be achieved.
• EPA is also using the data from the verification studies in deciding whether to withdraw or modify the
approved analysis method used for monitoring compliance with drinking water regulations.
• The ETV verification results have been used by state and federal agencies, including NOAA's National
Centers for Coastal Ocean Science Center for Coastal Environmental Health and Biomolecular Research
in Charleston, South Carolina, Nebraska Department of Environmental Quality, and Texas CEQ. Based in
part on the ETV results, a study sponsored by the American Water Works Association chose one of the
verified test kits for use in weekly sampling of 47 drinking
water facilities over a seven-month period.
References
U.S. EPA, ETV Case Studies: Demonstrating Program Outcomes, Vol-
ume II. EPA/600/R-06/082. September 2006. (primary source), http://
www.epa.gov/etv/pdfs/publications/600r06082/600r06082.pdf.
U.S. EPA, ETV, http://www.epa.gov/etv.
ETV Advanced Monitoring
Systems Center
Robert Fuerst, EPA
fuerst.roberti@,epa.gov
Tel: (919) 541-2220
Amy Dindal, Battelle
dindala@battelle.org
Tel: (561)422-0113
EPA/600/S-07/016
April 2007
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