California and Idaho Irrigation Canal Tour for Acrolein

(Meeting Summaries)

Acrolein is an aquatic herbicide used to control various weed species in
irrigation conveyance systems, primarily in the West, where off-farm
sources for irrigation water are well developed and important to
agriculture.  The EPA risk assessment and risk management team for
acrolein traveled to California and Idaho to discuss the use of acrolein
and to gain a better understanding of the use and need for this
chemical. 

California Air Resources Board Meeting- (4/9/08)

Attendees:

CA Air Resources Board (ARB)

CA Department of Pesticide Regulation (DPR)

US EPA Office of Pesticide Programs (HQ/OPP)

US EPA Region 9

On Wednesday, April 9, 2008, personnel from the Agency (SRRD, HED, EFED
and BEAD) traveled to Sacramento, CA to meet with representatives from
the California Air Resources Board (CARB) and California Department of
Pesticide Regulation (DPR) to discuss three recent air quality studies
measuring acrolein in and around irrigation canals.  CARB conducts
ambient air monitoring in California to assess air pollution exposures
to citizens.  CARB recently developed a method for measuring acrolein
concentrations in air from automobile/diesel exhaust, manufacturing and
forest fires.   DPR requested that CARB measure air concentrations of
acrolein resulting from herbicide applications to irrigation canals.   

Two of the CARB studies were cited in the Acrolein Human Health Risk
Assessment and showed canal side air concentrations above the EPA’s
level of concern.  CARB personnel presented the results of the third
study along with aerial photographs showing the proximity of residential
areas to canals.    It was interesting to note that in one of the air
monitoring studies conducted, elevated levels of acrolein were detected
at a significance distance downstream from the original application
site.  The distance traveled by the “slug”, which is volume of
treated water that moves downstream within the canal, should have
allowed the acrolein to dissipate along the way.  Confounding factors
such as nearby diesel exhaust may have contributed to these high levels.

HQ EPA (OPP), CARB and DPR personnel had an interesting discussion
regarding endpoints.  OPP’s endpoint is an irritation endpoint based
on a human study.   DPR’s endpoint is similar, but lower than OPP’s.
 Cal EPA is also looking at acrolein as a possible ozone depleting
chemical within the region; more specifically in the San Joaquin Valley.

California Department of Pesticide Regulation and County Agricultural
Commissioners Meeting- (4/9/08) 

Attendees:

Syed M. Ali- CA State Water Resources Control Board

Megan Bloodworth, Jose Bueno, Ada Ann Scott- CA Department of Pesticide
Regulation

Eric Smith, Rick Strider- CA Department of Pesticide Regulation
(Enforcement) 

Linda O’Connell- CA Department of Pesticide Regulation (Worker Safety)

Randy Segawa- CA Department of Pesticide Regulation (Environmental
Monitoring)

David Robinson, Sean Runyon- Merced County Ag. Commissioners Office

Jerry Prieto, Jr., Karen Francone- Fresno County Ag. Commissioners
Office

R David Jones, Kris Garber, Becky Daiss, John Pates, Laura Parsons,
Derek Berwald- US EPA Office of Pesticide Programs (HQ/OPP)

Patti TenBrook, Cindy Wire- US EPA (Region 9)

Marilou S. Lagasca- Kern County Agricultural Commissioner

On Wednesday, April 9, 2008, personnel from the Agency (SRRD, HED, EFED
and BEAD) traveled to Merced, CA to meet with representatives from
several County Agricultural Commissioner offices to discuss the use of
acrolein in and around irrigation canals.  

The County Agricultural Commissioner’s role is to enforce the
pesticide label restrictions on a local level.  As part of this role,
they are responsible for granting applications for restricted use
pesticides.  They also collect agricultural information and incident
data, which is then entered into a database.  This allows them a better
understanding of sensitive areas within their local jurisdiction in the
event that an application of a pesticide needs to take place.  This
involves a listing of species, such as endangered species, within the
proposed application site where an application of acrolein would not be
permissible.

When granting applications for restricted use pesticides, such as
acrolein, a Notice of Intent (NOI) must be submitted to the county
office and a pre-site inspection completed before an application can be
approved.  For sensitive sites, such as schools, buffer zones have been
established for certain counties and are determined independently by
each county commissioner.  Such is the case for restricted use
pesticides in Kern and Fresno County where there is an 1/8 mile buffer
zone in place.  In regards to the application, there is always an
official on site to observe and make certain that the application is
made at the requested site.  Additionally, agricultural commissioners
can also regulate to disallow an application such as along a public
right-of-way.

From 1983-2006 there have been 14 illnesses reported from the use of
acrolein.  Incident data has also shown that there have been reports of
some fish kills.  One instance happened in northern CA where ornamental
fish were killed, but the incident could have been avoided if the farmer
had heeded the warning/notice from the county that acrolein applications
were taking place.  Another instance involved a leaky gate where
acrolein was allowed to flow into a natural body of water resulting in
fish kills.  However, it should be noted that organic farmers and others
are notified prior to an application of acrolein; therefore, it is up to
the discretion of the irrigation district and farmers whether to take
water or not during this time period.

Seasonal distribution of water within the canal ends @July 31st, whereby
the use of groundwater wells is the common practice to deliver the
necessary remaining water to canal customers for their agricultural
needs.

California Acrolein Tour Irrigation Districts Meeting- (4/9/08)

Attendees:

Wes Croxen- Baker Petrolite

David Weisenberger- Banta-Carbona Irrigation District

R David Jones, Laura Parsons, Derek Berwald, Kris Garber, John Pates,
Becky Daiss- US EPA Office of Pesticide Programs (HQ/OPP)

Patti TenBrook, Cindy Wire- US EPA Region 9

John Mallyon- James Irrigation District

Terry Sutton, Sheridan Nicholas- Kern Delta Water District

Bob Acker, Tom Valenta- Merced Irrigation District

Ed Tobias, Walt Ward, Michael Niemi- Modesto Irrigation District

Kevin King- Oakdale Irrigation District

Yates Brooks, Ildo Martins- San Luis Water District

Jim Atherstone, Jeff Shields- South San Joaquin Irrigation District

Debbie Liebersbach, Keith Larson- Turlock Irrigation District

On Wednesday, April 9, 2008, personnel from the Agency (SRRD, HED, EFED
and BEAD) traveled to Modesto, CA to meet with managers from several
California Irrigation Districts to discuss enforcement issues, general
use practices, alternative use options and view a typical irrigation
canal.  

Irrigation districts managers are responsible for managing the districts
where applications are made.  When applications are being made, signs
are placed in the general area where acrolein is being applied in the
canal to let any unexpected passerby know to stay clear of the area. 
The majority of canals are located on private property, but contain
rights-of-ways to allow access to the canals for maintenance purposes
and are considered off-limits to the public.  No other postings are made
on the canals, but advisories are listed in the paper to warn of
upcoming applications.  Also, many of the canal systems are located in
close proximity to residential establishments.  However, the Agency was
informed that no acrolein applications are made near these types of
settings (dwellings).  

Since Sago pond weed is a common problem within the canal system,
acrolein is the preferred chemical of choice. Only a few other chemicals
can be used as aquatic herbicides within the irrigation canal system,
such as xylene, but offer little long term help, require higher rates of
application, or are more toxic than acrolein.  Chaining is another
alternative but is not a suitable method due to the expense in labor and
equipment costs as well as the risk of accidental injury from overturned
tractors and/or trucks.  The vastness of the canal system makes this
practice inefficient.

After having the opportunity of viewing one of the canals, it was quite
evident how important the conveyance system is to the agricultural
community.  Still, there remain many questions as to how to adequately
address bystander protection.

Boise Project Board of Control Meeting- (4/10/08)

Attendees:

Lynn Harmon- American Falls District

Dale Carpenter- Baker Petrolite

Dennis Heaps- Black Canyon Irrigation District

Bob Carter, Tim Page, Paul J. Deveau- Boise Project Board of Control

Dirk Helder, Kris Garber, Derek Berwald, Laura Parsons, R David Jones,
John Pates, Becky Daiss- US EPA Office of Pesticide Programs (HQ/OPP)

Sandy Halstead- US EPA Region 10

Bob Spencer- Idaho State Department of Agriculture

Norm Semanko- Idaho Water Users Association

John P. Anderson- Meridian Irrigation District

Billy Thompson, Michael Knight- Minidoka Irrigation District

John P. Anderson- Nampa Irrigation District

Ted Diehl, Larry Pennington- North Side Canal Company

Brian Olmstead- Twin Falls Canal Company

On Thursday, April 10, 2008, personnel from the Agency (SRRD, HED, EFED
and BEAD) traveled to Boise, ID to meet with irrigation district
personnel from across Idaho to discuss various weed control methods,
view irrigation water delivery systems and observe a mock application of
acrolein.

Discussions between the Agency and the irrigation personnel enabled a
more in-depth understanding of canal irrigation methods as well as
acrolein application and chemical management.  Over 750,000 of 2.5
million acres in Idaho are for agricultural use and part of the canal
conveyance system.  Acrolein is a vital tool for keeping the canals at
an optimum flow rate in order to deliver necessary water to farmers on
the lower end of the canal system.  

Irrigation personnel discussed several various methods of aquatic weed
control and explained the challenges for each method.  Shading is
another method that was contemplated for the purpose of weed control,
but it was agreed that the practice wouldn’t be feasible or work in
respect to the vastness of the conveyance system.  The idea of
introducing grass carp into the canal as a form of weed control was also
considered, but it was deemed to be labor intensive and costly.  The
Boise Project Board of Control also demonstrated the method of bank
thinning with the use of machinery that trimmed weeds from the canal
bank in an effort to control overgrowth.  However, it too is costly and
time consuming.  Interestingly, it was reported that the Twin Falls
Canal Co., in one year, uses the chaining method (basically a form of
dredging) on 1,500 miles of canal.  This process takes around the year
work to accomplish and is costly to maintain on a limited budget. In the
past, this method was accomplished by the use of horses up until 1980.  

Copper compounds can be used for algal control, and used in between
acrolein applications, but are not effective for weed control such as
Sago Pond Weed or American Pond Weed on a regular basis.  Xylene is
sometimes used but not preferred due to the necessary amounts needed for
application purposes.  Therefore, acrolein is almost exclusively the
chemical of choice due to its overall effectiveness.  The day also
included a mock application of acrolein so that EPA personnel could see
the safety precautions taken with applications.   Different stops of the
tour were the point at which the Boise River is diverted into the
irrigation system and the end of the canal system where the water flows
into a protected wetland.   The Idaho managers have many years of
experience with aquatic weed control and were generous with their time
and knowledge of the irrigation system in Idaho.

