United Stitn Office of Ptnictd* and Toxic Sutatancn
Environmental Pronction Office of Pentode Progr«m» (TS-766C)
Agency Wuhinqton. DC 20460
&EPA Pesticide
Fact Sheet
Name Of Chemical: Sodium arsenite
Reason for Issuance: Special review
Date Issued: Decenber 0986
FacTSheet Number: 113
1. DESCRIPTION OF CHEMICAL
Common Name: Sodium Arsenite
Chemical Name: Sodium Metaarsenite - NaAs02
Trade Names: Chem Pels C, Chem-Sen 56, Kill-All, Penite
Prodalumnol Double
EPA Shaughnessy Code: 013603
Chemical Abstracts Service (CAS) Number: 77784-46-5
Year of Initial Registration:
Pesticide Type: Acaricide, Fungicide," Herbicide, Insecticide,
Termiticide
Chemical Family: Inorganic Arsenicals
U.S. and Foreign Producers: Agtrol Chemicals, Fasey &
Besthoff, Inc.
2. USE PATTERNS AND FORMULATIONS
Sodium arsenite-is used as-a broad spectrum
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oai"
• Types and Methods of Application, Wind JP"y
hand application equipment, injection, dip, and
bait.
• Application Rates: Fungicide - 1.5 lb. arsenic/A
Types of Formulations: Flowable liquid, soluble concentrate,
wettable powder/dust
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3. SCIENCE FINDINGS
0 Chemical Characteristics
Sodium arsenite is a trivalent form of inorganic arsenic.
It normally exists as a gray—white powder with no discernible
odor. Sodium arsenite contains 58% arsenic and is very
soluble in water and alcohol. The boiling point of sodium
arsenite is 100°C, the density is 1.87 and the molecular
weight is 129.91. Sodium arsenite is a highly toxic sub-
stance with an acute oral LD 50 (mammalian) of 10—50 mg/kg.
° Toxicological Characteristics
Inorganic arsenical compounds have been classified as Class
A oncogens, demonstrating positive oncogenic effects based
on sufficient human epidemiological evidence.
Inorganic arsenicals have been assayed for mutagenic activity
in a variety of test systems ranging from bacterial cells
to peripheral lymphocytes from humans exposed to arsenic.
The weight of evidence indicates that inorganic arsenical
compounds are mutagenic.
Evidence exists indicating that there is teratogenic and
fetotoxic potential based on intravenous and Intraperitoneal
routes of exposure; however, evidence by the oral route is
insufficient to confirm sodium arsenite’s teratogeniC and
fetotoxic effects.
Inorganic arsenicals are known to be acutely toxic. The
symptoms which follow oral exposure include severe gastro-
intestinal damage resulting In vomiting and diarrhea, and
general vascular collapse leading to shock, coma and death.
Muscular cramps, facial edema, and cardiovascular reactions
are also known to occur following oral exposure to arsenic.
° Environmental CharacteriStlCs The environmental fate of
sodium arsenite is not well documented. However, because
of its extreme toxicity and Its solubility in soil moisture
and hence the hazard to water supplies, sodium arsenite is
not used now for many purposes formerly common practice.
Studies to demonstrate its fate must take into account the
fact that inorganic arsenicals are natural constituents of
the soil, and that forms of inorganic arsenic may change
depending on environmental conditions.
O Ecological Characteristics: Sodium arsenite is toxic to
birds, fish and aquatic invertebrate species.
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Metabolism: The metabolism of inorganic arsenic compounds
in animals is well known. The pentavalent form is metabo—
lized by reduction into the trivalent form, followed by
transformation into organic forms which are excreted within
several days via the urine. All animals exhibit this metabo-
lism except rats, which retain arsenic in their bodies for
up to 90 days.
o Tolerance Assessment: Tolerances were established in 40
CFR 180.335 for residues of the insecticide sodium arsenite
(expressed as As 2 0 3 ) resulting from dermal application to
animals under the supervision of the U.S. Department of
Agriculture. An interim tolerance of 0.05 ppm (as As 2 0 3 )
for grapes was established in 40 CFR 180.319.
o Reported Pesticide Incidents: The Agency’s Pesticide
Incident Monitoring System (PIMS) has many recorded inci-
dents of accidental poisonings from the use of sodium arsenite.
From 1966 to 1979, sixty—one reports involving humans were
reported. Eleven of these incidents involved hospitaliza-
tions and 24 involved child or adult fatalities.
4. SUMMARY OF REGULATORY POSITION AND RATIONALE
The Agency is proposing to cancel all existing nonwood
registrations of sodium arsenite, with the exception of the
fungicidal use on grapes. Measures to mitigate the inhalation
risks including dust masks, respirators, which would be
expected to reduce inhalation exposure by 80 and 90 percent,
respectively, and restricting the use to certified applicators
were considered by the Agency during the Special Review. The
Agency has determined that these protective measures would not
reduce risks to an acceptable level in light of the limited
benefits. The Agency has further determined that the tox-
icological risks from all nonwood uses of sodium arsenite, except
for the use on grapes, outweigh the limited benefits. The fungi-
cide use on grapes is being deferred pending further evaluation
by EPA’S Risk Assesment Forum of the carcinogenic potency of in-
organic arsenic from derma]. and dietary exposure.
o Benefits Analysis: No economic impact is expected as a result
of cancellation of the herbicide and insecticide registrations
of sodium arsenite.
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5. CONTACT PERSON
Douglas Mckinney
Special Review Branch, Registration Division
Office of Pesticide Programs (TS—767C)
401 M Street, S.W.
Washington, D.C. 20460
(703) 557—5488
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
or reregistration.
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