sodium arsenate EPA Pesticide Fact Sheet 12/86
EPA Pesticide Fact Sheet
Name of Chemical: Sodium arsenate
Reason for Issuance: Special review
Date Issued: December 1986
Fact Sheet Number: 114
1. DESCRIPTION OF CHEMICAL
- Common Name: Sodium Arsenate
- Chemical Name: Sodium Orthoarsenate - Na2HAsO4.7H20
- Trade Names: None
- EPA Shaughnessy Code: 013505
- Chemical Abstracts Service (CAS) Number: 7778-43-0
- Year of Initial Registration:
- Pesticide Type: Insecticide
- Chemical Family: Inorganic Arsenicals
- U.S. and Foreign Producers: Osmose Wood Preservative Company
of America, Inc.
2. USE PATTERNS AND FORMULATIONS
Sodium arsenate.is currently registered for use as an ant bait.
These baits are used in approximately 1% of U.S. homes.
- Methods of Application: Liquid bait applied where ants are seen.
Applied as a bait station using cardboard, waxpaper, cotton, or bottle
caps; or apply directly across ant trails and at entry points as a
thin line 3 to 4 inches long.
- Application Rates: Insecticide- The bait used is a 1.3% arsenic
- Types of Formulations: Ready to use solution, granular.
3. SCIENCE FINDINGS
- Sodium arsenate is a pentavalent form of inorganic arsenic. It is a
heptahydrate which normally exists as colorless crystals with no
discernible odor. Sodium arsenate contains 24% arsenic and is soluble
in 5.6 gm at 0 degrees C and 100 gm at 100 degrees C in 100 cc of
water, soluble in glycerol and slightly soluble in alcohol. The
melting point of calcium arsenate is 130 degrees C, the density is
1.88 and the molecular weight is 312.01. The technical chemical
contains 98% and the formulations contain from 0.92% to 3.08% sodium
- 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
arsenate'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 cardio-
vascular reactions are also known to occur following oral exposure to
- The environmental fate of sodium arsenate is not well documented.
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. Based on very limited data sodium arsenate is not
predicted to leach significantly.
- Sodium arsenate is moderately toxic to birds, slightly toxic to fish
and moderately toxic to aquatic invertebrate species.
- Metabolism: The metabolism of inorganic arsenic compounds in animals
is well known. The pentavalent form, such as sodium arsenate, is
metabolized 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 metabolism except rats,
which retain arsenic in their bodies for up to 90 days.
- Tolerance Assessment: A tolerance for residues of the insecticide
sodium arsenate on grapes was established at 3.5 ppm in 40 CFR
- Reported Pesticide Incidents: The Agency's Pesticide Incident
Monitoring System (PIMS) contains many recorded incidents of
accidental poisonings from the use of sodium arsenate baits. 190
children were involved in 186 reported incidents; five of these
children died and 43 were hospitalized.
4. SUMMARY OF REGULATORY POSITION AND RATIONALE
The Agency is proposing to cancel all existing nonwood registrations
of sodium arsenate. Based upon the risk of acute toxicity poisonings
and the other toxicological characteristics described above the Agency
has determined that in light of the limited benefits for nonwood uses of
sodium arsenate the risks of continued use outweigh the benefits.
- Benefits Analysis: No economic impact is expected as a result of
cancellation of this use. Comparatively priced alternatives are
5. CONTACT PERSON
Special Review Branch, Registration Division
Office of Pesticide Programs (TS-767C)
401 M Street, S.W.
Washington, D.C. 20460
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.