I
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
OFFICE OF
PREVENTION, PESTICIDES AND
TOXIC SUBSTANCES
Pesticide Fact Sheet
Name of Chemical: Flazasulfuron
Reason for Issuance: Conditional Registration
Date Issued: May 17, 2007
Description of Chemical:
Common Name:
Chemical Name:
Chemical Formula:
EPA PC Code:
Chemical Abstracts
Service (CAS) Number:
Year of Initial
Registration:
Pesticide Type:
Chemical Class:
U.S. Producer:
Flazasulfuron
N-[[(4,6-dimethoxy-2-pyrimidinyl) amino]carbonyl]
-3-(trifluoromethyl)-2-pyridinesulfonamide
CHi
104040-78-0
2007
Herbicide
Sulfonylurea
ISK Biosciences Corp.
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Use Patterns and Formulations
Application Sites:
Types of Formulations:
Application Methods
And Rates:
Flazasulfuron is registered for use on non-residential areas
including golf courses and non-residential turf areas such as
industrial parks, tank farms, sod farms, seed farms, sports
fields and commercial lawns.
Technical grade manufacturing use product (96.9% active)
Water-dispersible granule end-use product (25% active)
Flazasulfuron 25 WG Herbicide is to be used as a selective
herbicide for pre- and post-emergence. The product is
proposed as a selective herbicide for post-emergence with
some pre-emergence activity for control of a broadcast
spectrum of annual and perennial grasses, sedges and
broadleaf weeds in non-cropped areas growing on turf,
including golf courses. The herbicide is only to be applied
using ground application methods consisting of broadcast
foliar spray and spot treatments with backpack sprayers.
The maximum proposed application rate is 0.047 Ib ai/acre,
with three ground applications per season and 14-day
reapplication intervals.
Data Deficiencies
Additional information is needed to fulfill data requirements in the following areas:
• Aerobic aquatic metabolism
• Aerobic soil metabolism
• Anaerobic aquatic metabolism
• Soil mobility - batch-equilibrium adsorption/desorption
• Analytical Chemistry Methods (Water; Soil)
The submitted methods were not independently validated, as required.
• Fish early life-stage study
• Daphnid reproduction study
• Seedling emergence study
• Aquatic vascular plant (duckweed) study
• Acute neurotoxic study: FED is requesting historical positive control data, analytical data
verifying homogeneity, and stability of formulated test material for this study.
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Physical and Chemical Properties
Physicochemical Properties
Molecular Weight
Melting point/range
PH
Density
Water solubility (20 °C)
Solvent solubility (25 °C)
Vapor pressure (25 °C)
Dissociation constant, pKa
Octanol/water partition
coefficient, logPow (25 °C)
407.3 g/mol
147- 150 °C
4.01
0.79 g/cm3
pH
5
7
9
Solvent
hexanes:
octanol:
methanol:
acetone:
toluene:
di chl oromethane :
ethyl acetate:
acetonitrile:
mg/ml
0.027
2.1
Not Stable
Solubility
0.50 Dg/mL
0.20 mg/mL
4.2 mg/mL
22.7 mg/mL
0.56 mg/mL
22.1 mg/mL
6.9 mg/mL
8.7 mg/mL
< 1 x 10"7torr
4.37
pH 5 Buffer: 20
pH 7 Buffer: <10
Acute Toxicology
Technical flazasulfuron exhibits low acute toxicity.
Acute Toxicity Profile
Guideline
No.
870.1100
870.1200
Study Type
Acute oral [rat]
Acute dermal [rat]
MRID(s)
46220908
46220909
Results
LD50 > 5000 mg/kg
(male and females)
LD50 > 2000 mg/kg
(male and females)
Toxicity
Category
IV
III
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Acute Toxicity Profile
870.1300
870.2400
870.2500
870.2600
Acute inhalation
[rat]
Acute eye
irritation [rabbit]
Acute dermal
irritation [rabbit]
Skin sensitization
[guinea pig]
462209 10
46220911
46220912
46220913
LCso > 5 mg/L (male and
females)
Minimal conjunctivitis
through 48 hours. Free
by 72 hours.
No erythema, edema, or
dermal effects observed
at application site.
Not a sensitizer
IV
III
IV
-
Carcinogenicity
Based on lack of carcinogenic effects in the rat and mouse carcinogenicity studies and lack of a
mutagenicity concern, flazasulfuron can be classified as "No evidence of carcinogenicity to
humans".
Neurotoxicity
Neurotoxicity was observed using an acute neurotoxicity battery. A transient decrease in motor
activity on Day 0 (5 hours post-dosing) was observed at the mid dose of 1000 mg/kg.
Developmental Toxicity
Developmental toxicity has been investigated in two rat studies and one rabbit study. The effects
on reproduction have been examined in one rat study. Reduced fetal weights and retardation in
ossification were the effects observed in a Sprague-Dawley rat developmental study. A second
developmental rat study (Wistar) showed increased incidence of visceral malformations
(interventricular septal defect). The developmental study in rabbits showed high incidences of
abortion at the highest dose tested.
Reproductive Toxicity
Decreases in body weight and chronic nephropathy were observed in offspring in a 2-generation
rat reproduction study.
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FQPA Safety Factor
Because this is a non-food use pesticide, consideration of an FQPA Safety Factor is not required.
Toxicology Profile
Subchronic, Chronic and Other Toxicity Profile
Guideline No./
Study Type
MRID No. (year)/
Classification /Doses
Results
870.3100
90-Day oral
toxicity (rat)
46220920 (1988)
M/F: 0, 40, 200, 1000,
5000 ppm
M: 0,2.31, 11.66,57.1,
287 mg/kg/day
F: 0,2.53, 12.8,61.5,
309 mg/kg/day
Acceptable/Guideline
NOAEL (M/F) = 11.66/61.5 mg/kg/day
LOAEL (M/F) = 57.1/309 mg/kg/day based on
depression of body weight gain (M/F) and slight
anemia due to decrease in hemoglobin (F).
870.3150
90-Day oral
toxicity (dog)-
capsule
46220921 (1994)
M: 0, 2, 10, 50, 250
mg/kg/day
F:0, 2, 10,50, 100
mg/kg/day
Acceptable/Guideline
NOAEL (M/F) = 2/10 mg/kg/day
LOAEL (M/F) = 10/50 mg/kg/day based on changes in
liver (increase in: deposition of brown pigments,
glutamic pyruvic transaminase, creatine
phosphokinase, inflammatory cell infiltration,
microgranulomas).
870.3200
21-Day dermal
toxicity (rabbit)
46220922 (1994)
0, 250, 500, 1000
mg/kg/day
Acceptable/Guideline
NOAEL (M/F) = 1000/1000 mg/kg/day
LOAEL (M/F) = No systemic toxicity was observed at
the limit dose. No localized dermal effects were
observed.
870.3700a
Prenatal
developmental in
(rat):
Wistar
46220924 (1988)
0, 100, 300, 1000
mg/kg/day
Acceptable/Guideline
Maternal NOAEL = 100 mg/kg/day
LOAEL = 300 mg/kg/day based on increase in
maternal relative liver weight and decreased body
weight gain and food consumption.
Developmental NOAEL =100 mg/kg/day
LOAEL = 300 mg/kg/day based on increased
incidence of visceral malformations (interventricular
septal defect).
870.3700a
Prenatal
developmental in
(rat):
Sprague-Dawley
46220925 (1996)
0, 100, 300, 1000
mg/kg/day
Acceptable/Guideline
Maternal NOAEL = 300 mg/kg/day
LOAEL =1000 mg/kg/day based on transient
decreased body weight gain and food consumption.
Developmental NOAEL = 300 mg/kg/day
LOAEL = 1000 mg/kg/day based on reduced fetal
weights and retardation in ossification.
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Subchronic, Chronic and Other Toxicity Profile
Guideline No./
Study Type
MRID No. (year)/
Classification /Doses
Results
870.3700b
Prenatal
developmental in
(rabbit)
46220923 (1988)
0, 50, 150, 450
mg/kg/day
Acceptable/Guideline
Maternal NOAEL =150 mg/kg/day
LOAEL = 450 mg/kg/day based on high incidences of
abortion and decrease in food consumption after initial
administration.
Developmental NOAEL =150 mg/kg/day
LOAEL = 450 mg/kg/day based on high incidences of
abortion.
870.3800
Reproduction and
fertility effects
(rat)
46220926 (1995)
0, 200, 2000, 10000
ppm
M:0, 8.7, 87.5, 473.0
mg/kg/day
F:0, 11.7, 124.5,
613.7 mg/kg/day
Acceptable/Guideline
Parental/Systemic NOAEL (M/F) = 8.7/124.5
mg/kg/day
LOAEL (M/F) = 87.5/613.7 mg/kg/day based on
changes in kidney parameters (M/F: Bilateral
discoloration, enlargement, mild nephropathy) and
reductions in body weight in both generations (F0, FI).
Reproductive NOAEL (M/F) =473.0/613.7mg/kg/day
LOAEL (M/F) =not established.
Offspring NOAEL (M/F) = 87.5/124.5 mg/kg/day
LOAEL (M/F) = 473.0/613.7 mg/kg/day based on
reduction in lactational body weights of the Fj and F2
offspring.
870.4100b
Chronic toxicity
(dog)-capsule
46220927 (1995)
M: 0, 0.4, 2, 10, 50
mg/kg/day
F: 0, 2, 10, 50
mg/kg/day
Acceptable/Guideline
NOAEL = 2 mg/kg/day
LOAEL =10 mg/kg/day based on changes in liver
(increase in: inflammatory cell infiltration,
hepatocellular necrosis, hepatocellular swelling, and
bile duct proliferation).
870.4300
Combined
Chronic Toxicity/
Carcinogenicity
(rat)
46220929 (1995)
M: 0, 40, 400, 2000
ppm
F: 0, 40, 400, 4000
ppm
M:0, 1.3, 13.3,70.1
mg/kg/day
F: 0, 1.6, 16.4, 172.6
mg/kg/day
Acceptable/Guideline
NOAEL =1.3 mg/kg/day
LOAEL =13.3 mg/kg/day based on : Adverse change
in kidney function (chronic nephropathy) and kidney
physiology (enlargement, dark color of kidney)
no evidence of carcinogenicity
870.4200
Carcinogenicity
(mouse)
46220928 (1995)
0, 500, 3500, 7000 ppm
M: 0, 77.3, 552.7,
1053.8 mg/kg/day
F: 0, 93.7, 659.8,
1208.2 mg/kg/day
Acceptable/Guideline
NOAEL (M/F) = 77.3/93.7 mg/kg/day
LOAEL (M/F) = 552.7/659.8 mg/kg/day based on
decrease in body weight, body weight gain, food
consumption and an increase in liver effects (liver
weight and hepatocellular hypertrophy).
no evidence of carcinogenicity
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Subchronic, Chronic and Other Toxicity Profile
Guideline No./
Study Type
870.5500
Salmonella
typhimurium and
Escherichia coli
Reverse Mutation
Assay
870.5300
in vitro Mouse
Lymphoma
Mutagenesis
Assay
870.5375
in vitro
Cytogenetics Test
870.5395
in vivo
Mammalian
Erythrocyte
Micronucleus
Test: Mouse
870.6200a
Acute
neurotoxicity
screening battery
(rat)
MRID No. (year)/
Classification /Doses
46220933 (1987)
0, 20, 50, 100, 200,
500, 1000 Dg/ plate (S.
typhimurium); 0, 100,
200, 500, 1000, 2000,
5000 (E. coli} in the
presence and absence
of metabolic activation
(±S9)
Acceptable/Guideline
46220930 (1993)
0, 20, 30, 40, 50, 60,
70, 80, 90, 100, 500
Dg/ml in the presence
and absence of
metabolic activation
(±S9)
Acceptable/Guideline
46220931 (1988)
0, 3.3 xlO'4, 1.7 xlO'4,
8.3 xlO'5, 4.1xlO'5,
2.1xlO'5M, with and
without metabolic
activation (+ S9)
Acceptable/Guideline
46220932 (1995)
0, 1250, 2500, 5000
mg/kg
Acceptable/Guideline
46220934 (2002)
0, 50, 1000, 2000
mg/kg/day
Acceptable pending
data submission
/Guideline
Results
Flazasulfuron was not cytotoxic with or without S9
activation in four S. typhimurium strains and one strain
of E. coli, and did not induce a genotoxic response in
any strain.
Negative
There was no evidence of biologically significant
induction of mutant colonies.
Negative
Flazasulfuron did not induce chromosome aberrations
in Chinese hamster lung cells, in the presence and
absence of S9 activation.
Negative
There was no statistically significant increase in the
frequency of micronucleated polychromatic
erythrocytes in mouse bone marrow at any dose or
collection time.
Negative
NOAEL (M/F) = 50 mg/kg
LOAEL = 1000 mg/kg based on: transient decrease in
motor activity observed at Day 0 (5 hours post-dosing)
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Subchronic, Chronic and Other Toxicity Profile
Guideline No./
Study Type
MRID No. (year)/
Classification /Doses
Results
870.7485
Metabolism and
pharmacokinetics
(rat)
46220940 (1994),
46220941 (1995),
46220942 (1995),
46220943 (1995)
single dose: 2, 50
mg/kg
multiple dose: 2 mg/kg
Radiolabel:
(first ring: Pyridine
second ring:
Pyrimidine)
Acceptable/Guideline
Radiolabeled flazasulruron (Pyridine/Pyrimidine) was
rapidly distributed and excreted in the urine and feces
following multiple dosing. Urinary elimination,
calculated from a total collection of 168 hours,
occurred slower in males (74/73%) compared to
females (90/91%). Fecal elimination, calculated from a
total collection of 168 hours, was greater in males
(23/23%) than in females (10/9%). Radiolabel was
detected at low concentrations in carcass (M: 1.7/1.1%;
F:0.30/0.23%)), blood (M: 0.74/0.35%; F: 0.16/0.02),
liver (M: 0.23/0.14%; F: 0.04/0.04%), and kidney (M:
0.13/0.02%; F: 0.02/ <0.005%). Peak plasma
concentration following single dose administration
occurred at 6 hours in both sexes.
Toxicological Endpoints
Toxicological Doses and Endpoints
Exposure
Scenario
Acute Dietary
(Female 13-49)
Chronic Dietary
(all populations)
Incidental Oral
Short-Term
(1 - 30 days)
Dose Used in Risk
Assessment, UF
NOAEL =50
mg/kg
UF = 100
Acute RfD = 0.5
mg/kg
Oral
NOAEL =1.3
mg/kg/day
UF = 100
Chronic RfD =
0.013 mg/kg/day
NOAEL = 50
mg/kg
Special FQPA SF*
and Level of
Concern for Risk
Assessment
FQPA SF = IX
aPAD = acute RfD
FQPA SF
= 0.5 mg/kg
FQPA SF = IX
cPAD=chronic
RfD
FQPA SF
= 0.0 13 mg/kg/day
Occupational:
LOG for MOE =
100
Study and Toxicological Effects
Acute neurotoxicity (rat) LOAEL =
1000 mg/kg based on: transient
decrease in motor activity observed
at Day 0 (5 hours post-dosing).
Combined Chronic Toxicity/
Carcinogenicity rats
LOAEL= 13.3 mg/kg/day based on:
Adverse change in kidney function
(chronic nephropathy)
Acute neurotoxicity (rat) LOAEL =
1000 mg/kg based on: transient
decrease in motor activity observed
at Day 0 (5 hours post-dosing).
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Toxicological Doses and Endpoints
Exposure
Scenario
Incidental Oral
Intermediate -
Term
(1-6 months)
Dermal
Short-Term
(1 - 30 days)
Dermal
Intermediate -
Term
(1-6 months)
Dermal
Long-Term
(> 6 months)
Inhalation
Short-Term
(1 - 30 days)
Inhalation
Intermediate -
Term
(1-6 months)
Dose Used in Risk
Assessment, UF
NOAEL = 2
mg/kg/day
Oral
NOAEL = 50
mg/kg
(dermal absorption
rate = 45%)
Oral
NOAEL = 2
mg/kg/day
(dermal absorption
rate = 45%)
Oral
NOAEL =1.3
mg/kg/day
(dermal absorption
rate = 45%)
NOAEL = 50
mg/kg
(inhalation
absorption rate =
100%)
NOAEL = 2
mg/kg/day
(inhalation
absorption rate =
100%)
Special FQPA SF*
and Level of
Concern for Risk
Assessment
Occupational:
LOG for MOE=
100
Occupational:
LOG for MOE=
100
Occupational:
LOG for MOE =
100
Occupational:
LOG for MOE =
100
Occupational:
LOG for MOE =
100
Occupational:
LOG for MOE =
100
Study and Toxicological Effects
90-Day oral toxicity in (dog)
LOAEL= 10 mg/kg/day based on
changes in liver (increase in:
deposition of brown pigments,
glutamic pyruvic transaminase,
creatine phosphokinase,
inflammatory cell infiltration,
microgranulomas) .
Acute neurotoxicity (rat) LOAEL =
1000 mg/kg based on: transient
decrease in motor activity observed
at Day 0 (5 hours post-dosing).
90-Day oral toxicity in (dog)
LOAEL =10 mg/kg/day based on
changes in liver (increase in:
deposition of brown pigments,
glutamic pyruvic transaminase,
creatine phosphokinase,
inflammatory cell infiltration,
microgranulomas) .
Combined Chronic Toxicity/
Carcinogenicity rats
LOAEL= 13.3 mg/kg/day based on:
Adverse change in kidney function
(chronic nephropathy)
Acute neurotoxicity (rat) LOAEL =
1000 mg/kg based on: transient
decrease in motor activity observed
at Day 0 (5 hours post-dosing).
90-Day oral toxicity in (dog)
LOAEL =10 mg/kg/day based on
changes in liver (increase in:
deposition of brown pigments,
glutamic pyruvic transaminase,
creatine phosphokinase,
inflammatory cell infiltration,
microgranulomas) .
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Toxicological Doses and Endpoints
Exposure
Scenario
Inhalation
Long-Term
(> 6 months)
Cancer (oral,
dermal,
inhalation)
Dose Used in Risk
Assessment, UF
Oral
NOAEL =1.3
mg/kg/day
(inhalation
absorption rate =
100%)
Special FQPA SF*
and Level of
Concern for Risk
Assessment
Occupational:
LOG for MOE =
100
Study and Toxicological Effects
Combined Chronic Toxicity/
Carcinogenicity rats
LOAEL= 13.3 mg/kg/day based on:
Adverse change in kidney function
(chronic nephropathy) and kidney
physiology (enlargement, dark color
of kidney)
Classification: No evidence of carcinogenicity to humans
UF = uncertainty factor, FQPA SF = Special FQPA safety factor, NOAEL = no observed adverse effect level,
LOAEL = lowest observed adverse effect level, PAD = population adjusted dose (a = acute, c = chronic) RfD =
reference dose, MOE = margin of exposure, LOG = level of concern, NA = Not Applicable
Metabolism
Metabolism studies in the rat indicate that flazasulfuron is rapidly distributed and excreted in the
urine and feces. Excretion in urine occurred more slowly in males (73%) than females (90%).
Fecal elimination was greater in males (23%) than females (10%).
The most prevalent metabolites (expressed as percent of administered dose) were FfDTG+TPPG
(-6.5-17.7% in urine, -0.4-9.7% in feces, and -6.5-14% in bile), with minor amounts (<5%) of
other compounds. Individually, unidentified fractions generally accounted for less than 2% of
the administered dose in the urine and biliary metabolite profile. The fecal metabolite profile
had up to 35% unidentified of the recovered dose.
Drinking Water Exposure
Only acute and chronic dietary assessments were conducted for drinking water exposure because
flazasulfuron is not used on agricultural crops. Acute and chronic drinking water risk
assessments were conducted using the DEEM (DEEM-FCID™, Ver 2.03) which use water
consumption data from the USDA's Continuing Surveys of Food Intakes by Individuals (CSFII)
from 1994-1996 and 1998. The acute and chronic drinking water exposure/risk analyses for
flazasulfuron were conducted using unrefined Tier 1 drinking water exposure assumptions for all
uses. An estimated ground water concentration of 92 ppb was used for both the acute and
chronic drinking water assessments.
Results of the Tier I DEEM acute drinking water exposure analyses conclude that the acute and
chronic drinking water exposure estimates are below the Agency's level of concern. The DEEM
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acute drinking water exposure estimates at the 95th percentile for the highest exposed population
subgroup, all infants (< 1 year old), is 4% of the aPAD. The DEEM chronic drinking water
exposure estimates for the highest exposed population subgroup, all infants (< 1 year old), is
49% of the cPAD.
Based on the FIFRA Index Reservoir Screening Tool (FIRST) and the Screening Concentration
in Ground Water (SC-GROW) model the estimated environmental concentration (EECs) of
flazasulfuron in surface water are an acute EEC of 14.7 ug/L and a chronic EEC of 5.1 ug/L and
in ground water the acute and chronic EEC are 92 ug/L. These values are below the Agency's
level of concern.
Residential Exposure
Flazasulfuron is proposed for use on golf courses and athletic fields. Application of
flazasulfuron is to be made by professional pest control operators (PCOs) only. Therefore, non-
occupational handler exposure was not evaluated. Recreational post-application exposure via the
dermal route is likely for adults and children using golf courses or athletic fields.
Postapplication exposure is possible for recreational golfers who use the course after
flazasulfuron has been applied. The short-term MOE is greater than 100 on the day of
application, and therefore, is not of concern.
Post-application Short-Term MOEs for Golfers
Application
Rate (AR)
(Ibs ai/A)
0.047
TTR (ug/cm2)3
0.026
Transfer
Coefficient
(Tc)
(cm2/hr)
500
Exposure Time
(ET) (hrs/day)
4
Short-Term Dermal
ADD
(mg/kg/day)b
0.00034
MOEC
150,000
Dislodgeable Foliar Residue Postapplication day zero (ug/cm ) = Application rate (Ib ai/A) x Fraction of ai Retained on the Foliage
(0.05) x 4.54E+8 jjg/lb x 2.47E-8 A/cm2
a Default TTR value based on standard assumption of 5% of application rate for fraction of ai initially available.
b Average daily dose (ADD) (mg/kg/day) = [(TTR (ug/cm2) * Tc (cm2/hr) * 45% dermal absorption * mg/1,000 ug * ET (hrs/day)] / [70-kg BW]
c Short-Term MOE = NOAEL / ADD; Short-Term NOAEL = 50 mg/kg/day. The LOC is 100.
Postapplication exposure is also possible for people who use sports fields after flazasulfuron has
been applied. The short-term MOE for this scenario is above the LOC of 100, and is not of
concern.
Postapplication Dermal Exposure and Risk From Treated Turf
Subgroup
Exposed
Adults
Application
Rate
(Ib ai/A)
0.047
Dislodgeable
Foliar Residue
(ug/cm2)
0.026
Dermal
Transfer
Coefficient
(cm2/hr)
43,000
Body Wt
(kg)
70
Daily Dose2
(mg/kg/day)
Short-term
0.015
Dermal MOE3
Short-term
3,400
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1 Dislodgeable Foliar Residue Postappiication day zero (ug/cm2) = Application rate (Ib ai/A) x Fraction of ai Retained on the Foliage
(0.05) x 4.54E+8 jjg/lb x 2.47E-8 A/cm2
2 Daily Dose = [Dislodgeable Foliar Residue x Absorption Factor (0.45) x 0.001 mg/ug x Dermal Transfer Coefficient x
Exposure Time (2 hrs/day)]/Body weight
3 Dermal MOE = Dermal NOAEL/Daily Dose; where Short-term NOAEL = 50 mg/kg/day.
Occupational Exposure
Occupational Exposure is not of concern (MOEs > 100). There is a potential for exposure to
flazasulfuron during mixing, loading, and application activities.
Summary of MOEs for Occupational Handlers of Flazasulfuron
Exposure Scenario (Scenario
#)
Dermal Unit Exposure
(mg/lb ai) '
Baseline
PPE
(gloves)
Inhalation Unit
Exposure
Oig/lbai)2
Application
Rate
(Ib ai/A) 3
Area
Treated
(A/day)4
Total Short-term
MOE5
Baseline
PPE
(gloves)
Mixer/Loader
(1) Mixing/Loading Dry
Flowables for Groundboom
application
0.066
0.77
0.047
40
61,000
Applicator
(2) Applying Sprays with
Open Cab Groundboom
0.014
_
0.74
0.047
40
270,000
_
Mixer/Loader/Applicator
(3) Mixing/Loading Dry
Flowables and Applying with
Handgun Sprayer
(4) Mixing/Loading Dry
Flowables and Applying with
Low-Pressure Handwand
(3) Mixing/Loading Dry
Flowables and Applying with
Backpack Sprayer
no data
100
no data
0.59
0.43
2.5
2.2
30
30
0.047
0.00053
(Ib ai/gal)
0.00053
(Ib ai/gal)
5
40
(gal/day)
40
(gal/day)
no data
3,700
no data
56,000
140,000
1 Baseline dermal unit exposure values represent long pants, long sleeved shirts, shoes, and socks; PPE values represent the addition of chemical-
resistant gloves for those scenarios for which data are not available without gloves. Values are reported in the PHED Surrogate Exposure Guide
dated August 1998, except for the handgun value which was obtained from ORETF.
2 Inhalation unit exposure values represent no respirator. Values are reported in the PHED Surrogate Exposure Guide dated August 1998.
3 Application rates are based on maximum values found in label: Flazasulfruon 25WG (Reg No: 71512-XXX).
4 Daily area treated is based on the area or gallons that can be reasonably applied in a single day for each exposure scenario of concern based on
the application method and formulation/packaging type, (standard EPA/OPP/HED values).
5 ShorWIntermediate-Term MOE = NOAEL (50 mg/kg/day) / Total Daily Absorbed Short-Term Dose. The LOC is 100.
Total Daily Absorbed Dose (mg/kg/day) = {[(Dermal unit exposure * 45% Dermal absorption) + (Inhalation unit exposure * 100%
absorption)] * Application rate * Area treated} / 70-kg Body weight.
Postappiication inhalation exposure is expected to be negligible; however, dermal exposure is
possible for workers mowing/maintaining the turfgrass.
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Post-application Short-Term MOEs for Turf Maintenance Workers
Scenario
Maintenance
Activities
Turfgrass
TTR (ug/cm2)3
0.026
Transfer
Coefficient (Tc)
(cm2/hr)
3,400
Exposure Time
(ET) (hrs/day)
8
Short-Term Dermal
ADD
(mg/kg/day)b
0.0046
MOEC
11,000
a Default TTR value based on standard assumption of 5% of ai initially available from the application rate of 0.047 Ib ai/A.
b Average daily dose (ADD) (mg/kg/day) = [(TTR (ng/cm2) * Tc (cm2/hr) *45% dermal absorption * mg/1,000 ug * ET ( hrs/day)] / [70-kg BW]
c Short-Term MOE = NOAEL / ADD; Short-Term NOAEL = 50 mg/kg/day. The LOC is 100.
Residue Chemistry
There are no proposed tolerances for flazasulfuron.
Environmental Fate Characterization
Flazasulfuron is expected to be relatively persistent in soil and water (half-life about one month).
Flazasulfuron's persistence is likely to increase with increasing pH of the media. Chemical and
enzyme-mediated hydrolysis is a major route of transformation of flazasulfuron in water, soil,
and water-sediment systems. Both the rate (half-life) and mechanism of hydrolysis (i.e., how
products are formed) are pH dependent. There are four major hydrolytic and five metabolic
products. Flazasulfuron primarily forms bridge-contraction products. Flazasulfuron does not sob
strongly to soils and has the potential to leach to ground water and/or reach surface water during
runoff events. Flazasulfuron is a weak acid (pKa of 4.37). The mobility of flazasulfuron is
expected to increase with increasing pH. Flazasulfuron has low potential to volatilize from soil
or water or to bioaccumulate. A potential transport route is the wind erosion of soil particulates
containing flazasulfuron.
Environmental Effects Characterization
Flazasulfuron is practically non-toxic to freshwater and marine/estuarine fish and invertebrates,
birds, mammals, and bees and toxic to terrestrial and nonvascular aquatic plants.
Potential Risks to Non-Target Organisms
There is potential for direct adverse effects to non-target terrestrial and aquatic vascular plants.
There is potential for indirect adverse effects to animal species associated with the use of
flazasulfuron and indirect effects may result as a consequence of potential direct effects on
plants. Functionally, estimated risks may translate to reduced survival, reproduction, or growth
in affected species with the potential for subsequent effects at higher levels of biological
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organization.
For federally listed endangered or threatened species, direct effect LOCs were exceeded for
aquatic and terrestrial plants. There is potential for indirect effects to animals that depend on
plants for survival, growth, or reproduction.
RQs That Exceed the Acute Risk LOG
The listed and non-listed acute risk LOCs were exceeded for aquatic vascular
plants (RQ = 13 & 5.66). The listed and non-listed LOCs were exceeded for
terrestrial plants (see table below).
Terrestrial Plant Risk Quotient Summary for Flazasulfuron
Taxa
Non-endangered RQs
Terrestrial
Adjacent area
Turf (0.047 Ibs ai/A)
Ground spray application
Monocot
Dicot
94*
1.1*
Semi-aquatic
Adjacent area
800*
9.2*
Drift
Endangered RQs
Terrestrial
Adjacent area
16*
11.8*
67173**
2**
Semi-aquatic
Adjacent area
570714**
17**
Drift
11190**
22**
* RQ exceeds the Non-Endangered Species LOG; RQ >1 .0.
** RQ exceeds the Endangered Species LOG; RQ >1 .0.
The RQs for non-target plants in semi-aquatic and terrestrial areas adjacent to
agricultural fields irrigated with water containing flazasulfuron exceeded the non-
listed plant species LOCs (RQ = 2.4).
Label Modifications
The label will prominently state that flazasulfuron is not for use in areas where children can
contact treated turf.
The label will be clear that only 3 applications may be made per year.
Label language will be included stating that there is a potential for injury to crops irrigated with
run-off water containing flazasulfuron.
The following labeling will be required:
Environmental Hazards
Do not apply directly to water, or to areas where surface water is present or to intertidal
areas below the mean high water mark. Do not contaminate water when disposing of
equipment washwater or rinsate.
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Surface Water Label Advisories
This product may contaminate water through drift of spray in wind, or drift of soil from
treated areas.
This product has a high potential for runoff for several months or more 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
forecasted to occur within 48 hours.
Spray Drift Management
The following label statements concerning spray drift reduction should appear on the label:
AVOIDING SPRAY DRIFT AT THE APPLICATION SITE IS THE
RESPONSIBILITY OF THE APPLICATOR. The interaction of many equipment-and-
weather-related factors determines the potential for spray drift. The applicator is
responsible for considering all these factors when making decisions. Where states have
more stringent regulations, they should be observed.
Do not treat areas where either possible downwind movement into the soil or surface
washing may cause contact of Flazasulfuron 25WG herbicide with bentgrass greens and
stressed grasses.
Avoid making applications when spray particles may be carried by air currents to areas
where sensitive crops and plants are growing. Do not spray near sensitive plants if windy
is gusty, below 2 mph, or in excess of 10 mph and moving in the direction of adjacent
areas of sensitive crops or plants. Do not apply during temperature inversions. Always
make applications when there is some air movement to determine the direction and
distance of possible spray drift. Leave an adequate buffer zone of 100 feet between area
to be treated and sensitive plants.
To avoid injury to desirable plants, equipment used to apply Flazasulfuron 25WG
herbicide should be thoroughly cleaned (see PROCEDURE FOR CLEANING SPRAY
EQUIPMENT) before reusing to apply any other chemicals.
A label statement pertaining to mandatory spray drift reduction is required for all end use
products that allow for ground applications. Additional advisory language on spray drift
reduction may also be included. This advisory language will not supersede the mandatory label
requirements. The following risk reduction measures for spray drift are suggested for such a
label advisory.
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(1) INFORMATION ON DROPLET SIZE
The best drift management strategy is to apply large droplets and to limit or eliminate
small droplets. Applying large droplets reduces drift potential, but will not prevent drift
if applications are made improperly or under unfavorable environmental conditions (see
sections below).
(2) CONTROLLING DROPLET SIZE
o Volume - Use sufficient volume to form droplets large enough to avoid drift
potential.
o Pressure - Pressure and nozzle type and orientation should be carefully managed
to avoid formation of fine droplets.
o Number of nozzles - Use the minimum number of nozzles that provide uniform
coverage.
o Nozzle Type - Use a nozzle type that is designed for the intended application.
With most nozzle types, narrower spray angles produce larger droplets. Consider
using low- drift nozzles. Properly designed solid stream nozzles should produce
the lowest drift potential. Select nozzles, which do not have a wide discharge
profile.
(3) CALIBRATION
Equipment should be calibrated regularly according to the manufacturer's specifications.
(4) WIND
Applications should not be made when wind speed exceeds 10 mph. Use caution when
applying in wind speeds less than 2-3 mph because a temperature inversion may be
present and wind direction may vary. Many factors, including droplet size and
equipment, determine drift potential at any wind speed. The applicator should be familiar
with local wind patterns and should monitor wind conditions at the site at time of
application.
(7) SENSITIVE AREAS
It is the applicator's responsibility to exercise reasonable prudence when considering the
potential for drift into any area, including sensitive areas (e.g. areas where people or
nontarget plants may be present, bodies of water, known habitat for threatened or
endangered species, etc.).
(8) TEMPERATURE AND HUMIDITY
Low humidity and high temperature increase the evaporation rate of droplets and
therefore increase spray drift potential. The applicator should compensate for
temperature and humidity.
(9) TEMPERATURE INVERSIONS
Because of high drift potential, applications should not be made when droplets may reach
a temperature inversion layer. It is the applicator's responsibility to identify the presence
of a temperature inversion at the time of application. Accurate measurements of
temperature, relative humidity, and wind speed help determine if an inversion exists.
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Local sources of weather information may help identify the presence of temperature
inversions.
Contact Person at EPA
Jim Tompkins
Product Manager 25
Herbicide Branch
Registration Division (7505P)
Office of Pesticide Programs
Environmental Protection Agency
Aerial Rios Building
1200 Pennsylvania Ave., NW
Washington, DC 20460
Office Location and Telephone Number
One Potomac Yard
2777 S. Crystal Drive
Arlington, VA 22202
(703)305-5697
DISCLAIMER
The information presented in this Pesticide Fact Sheet is for informational purposes only
and may not be used to fulfill data requirements for pesticide registration and reregi strati on.
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