United State* Office of Pesticides and Toxic Substances
Environmental Protection Office of Pesticide Programs (TS-766C)
Agency Washington. DC 20460
vvEPA Pesticide
Fact Sheet
Name of Chemical:
Reason for Issuance: Registration of New Chemical
Date Issued: June 25, 1937
Fact Sheet Number: 138
1. Description of Chemical
Generic name: 0-(5-chloro-l-[methylethyl)-lH-l,2,4-triazol-3-yl)
0,0-d iethy1 phosphoroth ioa te
Common name: Isazophos (BSI)
Trade name: CGA-12223, Triumph
EPA Shaughnessy code: 124101
Chemical abstracts service (CAS) number: 42509-80-8
Year of initial registration: 1987
Pesticide type: Insecticide
Chemical family: Organophosphate
U.S. Producer: None
Foreign Producer: Ciba-geigy, Switzerland
2. Use Patterns and Formulations
Application sites: lawns
Types of formulations: liquid
Types/methods of application: ground spray
Application rates: 0.75 to 1.5 fl. oz. of product in a minimum of 3 gals, of
water per 1,000 sq. ft. of lawn. A maximum of 2.0 Ibs
a.i./A per year may be applied.
Usual Carriers: xylene
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3. Scierce Findings
Adequate studies are available to assess the toxicological and
envirorinental hazards of both the technical produt and the end—use
enulsifiable corcentrate prothrt for use on lawns. toxicological
or envirorinental hazards of corcern were identified fran use of these
pro&c ts when used according to preec ribed label directions.
Chanical characteristics
Physical state: slightly viscous liquid
Qior: characteristic org arxDphospborus odor
Color: pure material: colorless; technical material: yellow
iling point: 100°C at 0.001 mbar
ecific gravity: 1.22 g/cm 3 at 20°C
Solubility: ter: l5Oppn at 20°C
Vapor pressure: 4.3 x l0 mbar at 20°C
Mia ibility: miscible with methanol, chloroform, dichioranethane,
hexane, toluene, xylene.
Dnpirical formula: C 9 H 17 C1N 3 O 3 PS
Toxicology
Acute oral toxicity: f ran 33 mg/kg to 84 mg/kg in both male
arxi fanale rats (Tox Cat. I)
Acute inhalation: fran 0. 245 C to 1 89 C for both male and fenale
rats (Tox Cat. I)
Acute dermal (rabbit): intact: 870 i f kg
abraded: 571 mg/kg (Tox Cat. II)
Primary eye irritation: caused slight eye irritation in rabbits
which wes found to be reversible within
7 days (Tbx Cat. III)
Primary dermal irritation: caused slight dermal irritation in
rabbits (Tc)x Cat. IV)
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The no-thserved—effect levels ( )EL) for the chemical with respect to
cholinesterase inhibition are as follows:
Study mj/kg
90-day rat feeding 20 0.1
6-i onth dog feeding 0.05 0.0125
21—day dermal in rabbits ———— 0.1
ute delayed neurotoxic ity: The sutrnitted study shows that the
chemical does r t intk e delayed
neurotoxicity in female chickens at
a dose of approximately 25.4 mg/kg.
Terata3enicity: The ? EL for maternal toxicity in the rat and
rabbit were 6 mg/kg/day and 5 mg/kg/day,
respectively. The effects were clinical signs of
chol inesterase inhibition. Fetotox ic ity (runts)
were thserved in pregnant rats given the highest
dose tested (9 mg/kg). teratogenic effects were
thserved in the sutniitted studies.
Physiological and Biochemical Behavioral Characteristics :
Mechaniem of pesticidal action: cholinesterase inhibitor
Metaboli n and Persister e in Plants and Animals
The rretabolisn studies which were sutinitted suggest that CGk 12223 is
almost canpietely excreted within 24 hours after dosing of rats (93 to
97%). The primary route of excretion is the urine (approximately 99%
of the total excreted). The phosphorus—triazolyl ester bond is
cleaved, and the major portion of excreted residues in the urine
consists of glicuronic and sulfuric acid conjugates of the triazole
moiety or free triazole.
Environmental Characteristics
Studies show CX —12223 to be subject to relatively rapid degradation
by both hydrolysis and photolysis in aqueous solution. The hydrolysis
halflife at neutral pH is 48 days, while the half—life for photolysis
is approximately six days. The major degradation prcdi.ct (CG —17193)
of both reactions is the same and results fran cleavage of the phosphorus
ester bond to prcxhce the result ing hydroxy triazole. Metabolisn studies
indicate significant degradation of CGA—12223 in soil, with a half—life
of approximately 14 days under field conditions. As in the hydrolysis
and photolysis studies, the major degradation prothct in the soil metaboli n
studies was cGA—17193. CGA—12223 did r t significantly affect the growth
of soil mic roorganisns or, spec i fically, cellulose-decançosing mic roorgan iems
and did r t alter soil nitrification. Soil colunn leaching studies indicate
that the chemical has a high potential to leach in representative bare soils.
Dissipation f ran turf was found to be relatively rapid, with a half—life of
approximately 13 days. An in—house Pesticide ot Zone Model (PRZM)
simulation of miui ph used on turf shows that the chemical has little, if
any potential to leach, when used on turf.
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Bioa cunulation ratios in catfish exposed to a soil/water system re
very low, with maxim’ .nit values of 11X in the edible portion after one
day of exposure and 44X in the whole fish after 14 days.
Ecological char&teristics :
Avian aute oral toxicity (mallard duck) = 61 rr /kg
Avian dietary toxicity (mallard d k) = 244 prxn
(bobwhite quail) 81 ppn
Fish aute toxicity (rainbow trout) = .00636 ppn
(bluegill s’.jrifish) = .00383 ppn
(flathead minnow) = 0.138 ppn
Aquatic invertebrate toxicity (48 hr. — Daphnia magna) = 1.40 ppb
Avian reprcxkction: reprcxLctive eff ts at highest level tested
(30 p in) in both mallard duk and bobwhite
quail.
Ibxic ity to estuarine and marine animals:
96 hr.; sheepshead mirux)w = 6.02 ppb
E nbryo—Larvae and 1 i fe—cycle:
21—day life cycle (E phnia ma rma) =
> 0.198 and > 0.495 ug/L
early—life stage (fathead minnow) = MM
> 2.5 and > 6.3 ppb
Tolerar e asses Tients :
There are no tolerar es for the chemical. The use on lawns is a non—food
use.
4. St.minary of Regulatory Position and Required Unique Labeling
Use classification — use on lawns restricted to use only by certified
applications or persons under their direzt supervision. striction is
due to avian fish and aquatic organi n toxicity.
RDzmulation: 46.8% enulsifiable corcentrate.
An asses nent of potential exposure to h jnans re—entering lawns after
application of the pesticide as conducted. The dir t ccinparison of
detmal exposure estimates to a subohronic dennal toxicity EL
provides margin of safety (rIGS) ratios of 51.3, 25.6, and 17.3 for
1—, 2—, or 3—bour exposures.
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Based on data subnitted in support of a re—entry interval, the
following restriction is required on the labeling for use of the
chemical on lawns:
Dz not allow children or pets on the grass on
the day of treathLe t until 1/2 inch of water
has been applied and the grass is dry.
Based on results of the PRZM modeling for the use of the chemical on turf,
the following label restriction is required for use of the prcdtxt on
lawns:
l) not use on sandy soil.
5. Siminary of major data gaps
There are no data gaps for the registration of the chemical on lawns.
6. Contact person at EPA
William H. Miller
Prod t Manager (16)
Insec tic ide—Rodenticide Brarch
Registration Division (IS—767)
E virorinenta1 Protection Agency
Washington, ix : 20460
lephone Mimber (703) 557—2600
DISCLAIMER: The information presented in this themical Information Fact
Sheet is for informational purposes only and may ixt be used to fulfill
data requirements for pesticide registration and reregistration.
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