Ms. Linda Aschbrenner
State Registration Specialist
PO Box 12014
Research Triangle Park, North Carolina 27709
Dear Ms. Aschbrenner:
Re: Registration of One New Pesticide Product, Option Corn Herbicide (EPA Reg. No. 264-685), Which Contains the New
Active Ingredient Foramsulfuron
The New York State Department of Environmental Conservation (Department)
has reviewed your application,
received July 12, 2002, and additional information, received
October 21, 2002, to register one new pesticide product, Option Corn Herbicide (EPA Reg.
No. 264-685), in New York
State. The product contains the new active ingredient foramsulfuron (chemical code 122020).
The application was deemed complete for purposes of review on December 11,
2002 and a registration
decision is due by May 9, 2003.
Option Corn Herbicide (EPA Reg. No. 264-685) is a sulfonylurea herbicide
which is labeled for ground
application as a foliar spray in field corn for the control of annual and perennial grass
and broadleaf weeds. The
maximum application rate is 0.08 pounds of foramsulfuron per acre per year.
The Department has reviewed the information supplied to date in support of
registration of the new
product Option Corn Herbicide (EPA Reg. No. 264-685).
The New York State Department of Health (DOH) stated that neither foramsulfuron
nor Option Corn
Herbicide was very acutely toxic in animal studies by the oral, dermal or inhalation routes of
formulated product was slightly irritating to the skin and eyes (tested on rabbits) and had
properties (tested on guinea pigs), whereas the active ingredient was not irritating to skin
or eyes, and was not a dermal sensitizer.
Foramsulfuron did not cause effects in any of the subchronic, chronic,
developmental and reproductive
toxicity studies. All of these toxicity studies were tested at the limit dose of 1,000
milligrams per kilogram body
weight per day (mg/kg/day) or greater, except the rabbit developmental toxicity study
where the highest dose tested was
500 mg/kg/day. The United States Environmental Protection Agency (USEPA) designated
foramsulfuron as "not likely to be
carcinogenic to humans" based on a lack of evidence of carcinogenicity in rats and mice,
as well as a lack of effects in a number of genotoxicity studies.
The USEPA did not conduct either worker or dietary risk assessments for
foramsulfuron because no
significant adverse effects were reported for the subchronic, chronic, developmental and
reproductive toxicity studies.
In addition, the USEPA exempted foramsulfuron from the requirement of a tolerance.
There are no chemical specific federal or State drinking water/groundwater
standards for foramsulfuron.
Based on its chemical structure, this compound falls under the 50 microgram per liter
(_g/L) New York State drinking
water standard for "unspecified organic contaminants" (10 NYCRR Part 5, Public Water Systems).
The available information on foramsulfuron and Option Corn Herbicide
indicate that they are not very
acutely toxic in laboratory animal studies. In addition, foramsulfuron did not cause
toxicity in subchronic, chronic,
reproductive and developmental toxicity studies at the highest doses tested. The USEPA
did not conduct dietary or
worker risk assessments on foramsulfuron due to its demonstrated low toxicity. Because
the formulated product has
shown skin sensitization properties, the product's label cautions that "Prolonged or
frequently repeated skin contact
may cause allergic reaction in some individuals." To further mitigate exposure, the
Option Corn Herbicide label
requires the use of personal protective equipment including long-sleeved shirt, long
pants and chemical-resistant
gloves. Given the above, Option Corn Herbicide use should not pose a significant risk
to workers or the general public.
The Department's Division of Fish, Wildlife & Marine Resources' Bureau
of Habitat (BOH) reviewed the
information submitted in support of registration of Option Corn Herbicide and stated
that they have no objection to registration.
ENVIRONMENTAL FATE AND GROUNDWATER IMPACTS:
The Department's groundwater staff stated the following:
Hydrolysis: Hydrolysis of this acidic compound was highly sensitive to pH and
temperature, slowing dramatically
above pH 5 and with decreasing temperature. The USEPA-calculated half-life was 4.5
days at pH 4, 10.6 days at pH 5,
156 days at pH 7 and 176 days at pH 9. At pHs 4 and 5, degradates AE F153745 and AE
F092944 were found at a maximum of
74.7% and 83.3%, respectively. At pHs 7 and 9, degradates AE F130619, AE F092944, AE
AE 0001082 were found at a maximum of 29.6%, 33.3%, 15.6% and 10.7% respectively.
AE F130619 was the only degradate that retained the sulfonylurea bridge.
Photolysis: Foramsulfuron is stable to aqueous and soil photolysis.
Aerobic Soil Metabolism: The combination of this study and several other aerobic
soil metabolism studies in
different soils and under different experimental conditions of temperature and relative
soil moisture satisfy the data
requirement for aerobic soil metabolism. Foramsulfuron is relatively short-lived and
degradation is bi-phasic. In
three soils, the two-compartment DT50 day value was 1.2, 3.5 and 9.5. The two-compartment
DT90 day value was 40, 13
and 51 days, respectively. Two major organic metabolites were identified and quantified.
AE F130619 was found at 31%
of applied radioactivity at day one, and AE F092944 reached 27% of applied at 22 days.
AE F130619 appeared to decline
rapidly in a few days, and AE F092944 appeared to be persistent in all soils ("half-lives"
hundreds of days). The
USEPA Pesticide Fact Sheet for Foramsulfuron, dated March 27, 2002, indicates that the
parent has an aerobic soil metabolism half-life of 40 days.
Degradate Aerobic Soil Metabolism: Radiolabeled AE F130619 was short lived in the
four soils tested in this
study. Most striking was the rapid formation of large fractions of unextracted soil residues
(up to approximately 100%
near the end of the 120 day test period). The major identified metabolite was AE F092944.
Aerobic Aquatic Metabolism: In two different laboratory sediment/water systems, the
two-compartment values at DT50 were 34 and 55 days for non-sterile samples and 87 days and
190 days for sterile
samples; the DT90s were 110 and 180 days for non-sterile and 290 days and 634 days for
sterile samples. Two major
degradates were formed: AE 0338795 up to 25%, and AE F153745 up to 25%. Five minor
degradates were formed.
Anaerobic Aquatic Metabolism: Five minor degradates were formed, but no major degradates.
The USEPA Pesticide Fact Sheet for Foramsulfuron, dated March 27, 2002, indicates that it has
an anaerobic aquatic metabolism half-life of 76 days.
Adsorption/Desorption: Kocs for foramsulfuron were 151 for a silty clay loam, 89 for a
loamy sand, 51 for a
loamy sand, 38 for sand and 63 for clay. The USEPA Pesticide Fact Sheet for Foramsulfuron,
dated March 27, 2002,
indicates that it is weakly sorbed to soils.
Degradate Adsorption/Desorption: Kocs for AE F153745 were 63 for a sand soil, 35 for
a clay loam soil, 50 for a
sandy loam soil, and 48 for a loam soil.
Degradate Adsorption/Desorption: Desorption Phase 2 of the bi-phasic desorption Kocs for
AE F130619 were 199 for a sandy loam soil, 186 for a sand soil, 132 for a clay loam soil and
465 for a loam soil.
Degradate Adsorption/Desorption: Kocs for AE F092944 were 211 in a sand, 89, 625 and
663 in loamy sands, 696
and 395 in sandy loams, 11289 in a silt loam and 917 in a silty clay. This degradate was
previously know as Hoe 092944.
Lysimeter Study: The mobility of foramsulfuron was studied in an English sand soil.
Two lysimeters were
prepared and planted with maize the first year, and wheat subsequently. Precipitation was
augmented with irrigation.
Bromide tracer broke through approximately 4 months after the first application. The
maximum amount of tracer occurred
at 5 months and 8 months. Collected leachate in the first two years accounted for 42-50%
of the total water input.
Degradate AE F130619 was present in the leachate at a maximum of 0.005 g ai equivalents/L.
No parent or other degradate was detected in the leachate. When the final soil columns
were tested, foramsulfuron, AE
F099095, AE F 092944 and AE F130619 were present down to the
0-10 cm depth at 0.01-0.15%, 0.74-0.85%, 0.5-0.61% and 0.37-0.53% of the applied respectively,
and each were present
in the 10-20 cm depth at 0.20% of the applied. Unextracted residues present in the 10-20 cm
and 20-30 cm depths were
5.54-10.06% and 1.43-2.95% of the applied, respectively. Total residues present in the maize,
wheat and weeds were 0.44-1.67%, 0.01% and
0.61-1.02% of applied, respectively.
Field Dissipation: USEPA found this study to be supplemental and in partial fulfillment
of the requirements.
Parent foramsulfuran was not found at the four study sites with reviewer-calculated first-order
half-lives ranging from 11-18 days.
Label Statements: The following statements appears on the label:
Surface Water Advisory - This product has a high potential for runoff after application. Poorly draining soils
and soils with shallow water tables are more prone to produce runoff that contains this product. A level,
well-maintained vegetative buffer strip between areas to which this product is applied and surface water features such
as ponds, streams, and springs will reduce the potential for contamination of water from rainfall runoff. Runoff of
this product will be reduced by avoiding applications when rainfall is forecast to occur within 48 hours. Sound
erosion control practices will reduce this product's contribution to surface water contamination.
Soil Insecticide Interaction Information - When Option Corn Herbicide and organophosphate (OP) insecticides are
applied to corn, the degradation of Option Corn Herbicide is slower and corn injury can occur. DO NOT USE Option Corn
Herbicide in the same season as Counter 15G, Counter 20CR, Dyfonate and Thimet.
Computer Modeling: Modeling by the Department on Riverhead sand, using 0.08 lb ai/a/yr,
a Koc of 89 for both
the parent and the degradate (27%) and an aerobic half-life of 40 days projected breakthrough
for the parent in the
second year, and peaks starting in the second year ranging between 0 and less than 0.03 ppb.
The model predicted the
degradate AE F092944 had breakthrough at about 4 months, and peaks ranging from less than 0.1
to less than 0.3 ppb.
Changing to the field dissipation half-life of 18 days, the model projected breakthrough for
the parent in the second
year, and peaks starting in the second year ranging between 0 and less than 0.02 ppb. For the
degradate, the model
projected breakthrough in four months, and peaks starting in the second year ranging from
between 0 and 0.2 ppb.
While this active ingredient has fairly low Kocs and is mobile, the application rate is low
and the half-lives are not
long. The soil insecticide interaction information indicates that the degradation rate will
be slower if the product
is used with OP insecticides, which if modeled would indicate persistence and accumulation.
However, even if the
product is used in conjunction with the above-referenced OP products, it is staff's opinion
that the leaching rate
would still be very low.
The Department concludes that Option Corn Herbicide should not have an adverse
effect on the health of
workers or the general public, the fish and wildlife resources, or the ground and surface water
of New York State when used as labeled.
Therefore, the Department hereby accepts for registration the new product
Option Corn Herbicide (EPA
Reg. No. 264-685).
Enclosed are your New York State stamped "ACCEPTED" label and a copy of
the Certificate of Registration.
Bayer CropScience is reminded that if New York State registration is requested
for this product or for
any other product which contains foramsulfuron with an increased application rate and/or
expanded use sites, the
product will be considered a Major Change in Labeling and the Department will require an
If you have any questions, please contact Mr. Samuel Jackling, Chief of
our Pesticide Product
Registration Section, at (518) 402-8768.
Maureen P. Serafini
Bureau of Pesticides Management
N. Kim/D. Luttinger - NYS Dept. of Health
R. Zimmerman/ R. Mungari - NYS Dept. of Ag. & Markets
G. Good/W. Smith - Cornell University, PMEP