E X T O X N E T
Extension Toxicology Network
A Pesticide Information Project of Cooperative Extension Offices of
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University of California at Davis. Major support and funding was provided
by the USDA/Extension Service/National Agricultural Pesticide Impact
Assessment Program.
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Pesticide
Information
Profile
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Diphacinone
Publication Date: 9/93
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TRADE OR OTHER NAMES
Common names include diphacin (Italy and Turkey), ratindan (USSR),
dipazin, diphenadione and diphenacin (2). Trade names include
Diphacine, Ditrac, Gold Crest, Kill-Ko, P.C.Q., Promar, Ramik, Rat
Killer, Rodent Cake.
REGULATORY STATUS
All formulations containing 3% or more of diphacinone are
classified as Restricted Use Pesticides (RUP) by the EPA. RUPs may be
purchased and used only by certified applicators. The signal word
required on products containing diphacinone varies, depending on the
type of formulation. "Danger" is required for the technical material.
"Warning" is required for concentrate formulations and "Caution" is
required for bait formulations (3).
INTRODUCTION
Diphacinone is an anti-coagulant rodenticide bait used for control
of rats, mice, voles and other rodents. It is available in meal,
pellet, wax block, and liquid bait formulations, as well as in tracking
powder and concentrate formulations.
TOXICOLOGICAL EFFECTS
ACUTE TOXICITY
Diphacinone is highly toxic to humans and other mammals by
inhalation, dermal absorption, and ingestion (4). It causes internal
hemorrhaging that can lead to death. It acts by inhibiting enzymes
involved in blood clotting (2). Animals given lethal doses exhibited
labored breathing, muscular weakness, excitability, fluid in the lungs,
and irregular heartbeats. Other signs of poisoning include spitting of
blood, bloody urine or stools, internal hemorrhaging, and widespread
bruising or bleeding into the joints. When a lethal dose does not cause
immediate death, then death tends to be delayed and due to massive
hemorrhage (4).
Diphacinone does not irritate the skin and it is not a skin
sensitizer (2). It is a mild eye irritant.
The amount of a chemical that is lethal to one-half (50%) of
experimental animals fed the material is referred to as its acute oral
lethal dose fifty, or LD50. The oral LD50 for technical diphacinone in
rats is 0.3 to 7 mg/kg, 3.0 to 7.5 mg/kg in dogs, 14.7 mg/kg in cats,
150 mg/kg in pigs, 50 to 300 mg/kg in mice, and 35 mg/kg in rabbits (2,
3, 4). The dermal LD50 in rats is 200 mg/kg (4), and in rabbits is
greater than 3.6 mg/kg. The lethal concentration fifty, or LC50, is
that concentration of a chemical in air or water that kills half of the
experimental animals exposed to it for a set time period. The 4-hr
inhalation LC50 in rats is 2 mg/m3 (4, 6).
CHRONIC TOXICITY
EPA does not require data on the chronic health effects of
diphacinone because this pesticide is used in a manner which poses only
a minimal hazard of chronic human exposure.
Reproductive Effects
Because diphacinone is used in a manner which poses no hazard of
chronic exposure to humans, EPA does not require testing for potential
effects on reproduction.
Teratogenic Effects
Tests results regarding potential teratogenicity of diphacinone
will be submitted to EPA by June of 1993.
Mutagenic Effects
Diphacinone was not mutagenic in the Ames test (2). Mutagenicity
data was under review by EPA during October 1992.
Carcinogenic Effects
Because diphacinone is used in a manner which poses only a minimal
hazard of chronic exposure to humans, EPA does not require testing for
potential carcinogenic effects.
Organ Toxicity
Poisoning by diphacinone may affect the heart and gastrointestinal
system (4).
Fate in Humans and Animals
Three to 7.5 hours after radio-labeled diphacinone was given orally
to mice, the highest concentrations appeared in the liver and lungs. In
another study, rats given oral doses eliminated 70% of the dose in the
feces and 10% in the urine within 8 days. A similar pattern of
elimination occurred in mice given the same treatment. Levels of
diphacinone were highest in the liver and significant in the kidneys and
lungs 4 and 8 days after treatment for rats and mice respectively.
Diphacinone is not extensively metabolized in rats, with less than 1% of
the dose expired as carbon dioxide (2).
The half-life of diphacinone in humans is 15 to 20 days (2).
ECOLOGICAL EFFECTS
Effects on Birds
Diphacinone is slightly toxic to birds. The oral LD50 for
diphacinone in mallard ducks is 3158 mg/kg (2, 5), and in bobwhite quail
is 1630 mg/kg.
Effects on Aquatic Organisms
Diphacinone is slightly to moderately toxic to fish. The 96-hour
LC50 for technical diphacinone in channel catfish is 2.1 mg/l, for
bluegills is 7.6 mg/l, and for rainbow trout is 2.8 mg/l (1, 5). The
48-hour LC50 in Daphnia, a small freshwater crustacean, is 1.8 mg/l.
Effects on Other Animals (Nontarget species)
No information available.
ENVIRONMENTAL FATE
Breakdown of Chemical in Soil and Groundwater
Diphacinone has a low potential to leach in soil (6).
Breakdown of Chemical in Water
Diphacinone is rapidly decomposed in water by sunlight (2).
Breakdown of Chemical in Vegetation
No information available.
PHYSICAL PROPERTIES AND GUIDELINES
Technical diphacinone is an odorless, pale yellow powder (3).
Diphacinone is stable under normal temperatures and pressures. It may
burn, but does not ignite readily. Thermal decomposition of diphacinone
may release carbon monoxide and carbon dioxide (4, 1).
Exposure Guidelines:
No occupational exposure limits have been established for
diphacinone by OSHA, NIOSH or ACGIH (4).
Physical Properties:
| CAS #: | 82-66-6 |
| Specific gravity: | 1.6 |
| H20 solubility: | almost insoluble; 0.3 mg/l (2, 4) |
| Solubility in other solvents: | soluble in acetone (29 gm/l), acetic acid and toluene (73 gm/l). slightly soluble in benzene (2, 4) |
| Melting point: | 295-297 degrees F (146-147 degrees C) (4) |
| Decomposition temperature: | Technical material decomposes at 338 degrees C without boiling (5) |
| Vapor pressure: | 13.7 mm Hg at 25 degrees C (technical) (5) |
| Chemical Class/Use: | anticoagulant rodenticide |
BASIC MANUFACTURER
Bell Laboratories, Inc.
3699 Kinsman Blvd.
Madison, WI 53704
Hacco Inc.
P.O. Box 7190
537 Atlas Ave.
Madison, WI 53707
Telephone: 608-221-6200
Review by Basic Manufacturer - Bell Labs:
Comments solicited: October, 1992.
Comments received: November, 1992.
Review by Basic Manufacturer - Hacco Inc.:
Comments solicited: October, 1992.
Comments received: November, 1992.
REFERENCES
Bell Laboratories, Inc. July, 1990. Diphacinone Technical: MSDS.
Bell Labs, Madison, WI.
Hayes, W.J. and E.R. Laws (ed.). 1990. Handbook of Pesticide
Toxicology, Vol. 3, Classes of Pesticides. Academic Press, Inc., NY.
Meister, R.T. (ed.). 1992. Farm Chemicals Handbook '92. Meister
Publishing Company, Willoughby, OH.
Occupational Health Services, Inc. 1991 (Sept. 16). MSDS for
Diphacinone. OHS Inc., Secaucus, NJ.
Worthing, C.R., ed. 1983. The Pesticide Manual: A World
Compendium, 7th Ed. British Crop Protection Council, Croydon, England.
US Environmental Protection Agency. 1991 (Feb 25). Pesticide
Environmental Fate One Line Summary: Diphacinone. Environmental Fate
and Effects Div., US EPA, Washington DC.
Disclaimer: Please read
the pesticide label prior to use. The information contained at this web
site is not a substitute for a pesticide label. Trade names used herein
are for convenience only; no endorsement of products is intended, nor is
criticism of unnamed products implied. Most of this information is historical
in nature and may no longer be applicable.
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