Document ID: EPA-HQ-OPP-2007-0934-0022
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2008-01-07T05:00Z

Statement of National Corn Grower Association

Presented by DaNita Murray, Director of Public Policy

Before the EPA FIFRA Scientific Advisory Panel on Atrazine

Purpose:  To consider and review the interpretation of the ecological
significance of atrazine stream-water concentrations using a
statistically-designed monitoring program

December 4, 2007

Thank you for the opportunity to comment.  My colleague, Lisa Kelley,
was scheduled to be here today but unforeseen circumstances have caused
her to be out of town.

The National Corn Growers Association (NCGA) was founded in 1957 and
represents more than 32,000 members in 48 states, 47 affiliated state
organizations and more than 300,000 corn farmers who contribute to state
check-off programs for the purpose of creating new opportunities and
markets for corn growers. 

How well a producer controls weeds makes all the difference in their
yields and return on investment.  Corn growers depend on the safe,
effective use of atrazine and pre-packs containing atrazine to control
weeds on about two-thirds of the country’s corn acreage.  By using
atrazine over alternative herbicides, farmers save an average of $28 per
acre in herbicide costs and yield advantages, according to a review by
the U.S. Environmental Agency (EPA, 2003). 

Atrazine is the most thoroughly tested herbicide ever used in crop
protection, with the weight of evidence of nearly 6,000 scientific
studies supporting its safety.  In 2006, EPA re-registered atrazine
after a more than a decade of intense scientific review.  However, as a
condition of re-registration EPA required the registrant to develop a
monitoring program to determine whether atrazine concentrations in
streams associated with corn and sorghum production were exceeding a
designated and extremely conservative effects-based threshold based on
aquatic plant communities.  For over two years, Syngenta has conducted
this intensive monitoring program in the most vulnerable watersheds in
Midwest corn production and determined that there are minimal to no
effects on these aquatic communities from atrazine use when the modeling
system is used appropriately.

NCGA believes that in some areas EPA’s inputs to the model could be
readily corrected. For example, EPA pushes the simulation back to
January 1 in the model year, long before the first application of
atrazine when the first detections of atrazine in streams are possible
(about day-105 of the year).  EPA’s assumptions and input to the model
artificially presume that concentrations of atrazine are impacting a
watershed when in fact atrazine applications do not occur until time to
plant corn.  The model incorrectly assumes that low levels of atrazine
have a biological impact. 

Additionally, NCGA notes that the model assumes that common rooted
vascular plants (macrophytes) are a large part of the aquatic ecosystem
early in the year.  In the winter months in the Midwest this would be
extremely uncommon.  In fact these types of plants are not typically
found in the headwater streams monitored in this program.

EPA has stated that it will return to another SAP when it corrects the
way the model seems to overestimate the effects of extended-duration,
low-level exposures and the apparent underestimate of the effects of
short-term, high-level exposures. We note that, high level exposures of
atrazine would likely not affect the aquatic community since the mode of
action of atrazine (inhibition of photosynthesis) is reversible.  The
streams and ecosystems on our growers farms are extremely resilient and
would easily recover from this type of exposure.

Moreover, no-till agriculture becomes impossible without herbicide use,
resulting in increased erosion estimated to be more than 300 billion
pounds of soil annually or a 15 percent increase. Much of this soil
erosion would enter waterways and significantly reduce the quality of
the nation’s surface water.  Soil erosion causes siltation -- the most
significant problem facing waterways in agricultural regions.  When
rooted plants as well algae in streams are restricted in growth it is
often by lack of light from erosion-borne sediment deposition. 
According to the U.S. Department of Agriculture, atrazine is the most
widely used herbicide in conservation tillage systems, which reduces
soil erosion by as much as 90%.  

In conclusion, corn growers are committed to leaving our environment in
better shape than we found it.  NCGA believes that atrazine is used
safely on farms in the U.S. without any detrimental effects to aquatic
communities.  We believe that the Agency should complete the corrections
to the model to show that additional monitoring is not necessary.  We
appreciate the opportunity to comment.