calcium arsenate (Pencal, Security) EPA Environmental Fact Sheet 8/90
EPA Environmental Fact Sheet 8/90
I. DESCRIPTION OF CHEMICAL
- COMMON NAME: Calcium arsenate
- CHEMICAL NAME: Calcium Orthoarsenate - Ca3(AsO4)2
- TRADE NAMES: Pencal, Security
- EPA SHAUGHNESSY CODE: 013501
- CHEMICAL ABSTRACTS SERVICE (CAS) NUMBER: 7778-44-1
- PESTICIDE TYPE: Crop herbicide, Insecticide and molluscicide
- PESTICIDE FAMILY: Inorganic arsenicals
- U.S. AND FOREIGN PRODUCERS: Woolfolk Chemical Works, Inc., Commercial
II. USE PATTERNS AND FORMULATIONS
Calcium arsenate was registered as a foliar insecticide on various
small fruits and berries and certain vegetable crops. It was applied at
a rate of 4.5 lb. active ingredient/acre. As a molluscicide, calcium
arsenate bait was composed o f 80% bran, 10% molasses and 10% calcium
arsenate. It was applied to the soil near plants for protection.
III. SCIENTIFIC FINDINGS
Calcium arsenate is a pentavalent form of inorganic arsenic. It
normally exists as white crystals with no discernable odor. Calcium
arsenate contains 38% arsenic and is very slightly soluble in cold water
and soluble in dilute acids. The melting point is 1045 degrees C; the
specific gravity is 3.62 and the molecular weight is 398.08.
Inorganic arsenical compounds have been classified as Group A, or
known human carcinogens.
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 inorganic arsenical compounds are mutagenic.
Evidence exists there is teratogenic and fetotoxic potential based on
intravenous and intraperitoneal routes of exposure; however, evidence by
the oral route is insufficient to confirm calcium arsenate's teratogenic
and fetotoxic effects.
Inorganic arsenicals are known to be acutely toxic. The symptoms
which follow oral exposure include severe gastrointestinal 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
Studies to demonstrate calcium arsenate's fate must take into account
the fact that inorganic arsenicals are natural constituents of the soil,
and that forms of inorganic arsenicals may change depending on
environmental conditions. Based on limited data, calcium arsenate is
not predicted to leach significantly.
Calcium arsenate is moderately toxic to birds, slightly toxic to fish
and moderately toxic to aquatic invertebrate species.
On October 18, 1978, EPA issued a Notice of Rebuttable Presumption
Against Registration (RPAR) -- now called Special Review -- of pesticide
products containing inorganic arsenic (as well as creosote, coal tar,
coal tar neutral oils, and pentachlorophenol).
On January 2, 1987, EPA proposed to cancel most registrations for
inorganic arsenicals, including the food uses of calcium arsenate, based
on acute toxicity from accidental ingestion and oncogenic risks posed to
workers. The final determination to cancel these registrations was
issued June 30, 1988 (53 FR 24787). In that Notice, the sale,
distribution and use of food use products containing calcium arsenate,
among other inorganic arsenical products, was prohibited after August 1,
V. PROP0SED TOLERANCE EVOCATION
EPA is proposing to revoke all tolerances for calcium arsenate, which
are found at 40 CR 180.192. No action levels will be recommended to
replace the tolerances proposed for revocation.
VI. REGULATORY POSITION AND RATIONALE
Calcium arsenate was registered for food use as an insecticide on
various field and orchard crops. The cancellation of these
registrations, based on acute toxicity, were announced in a June 30,
1988 Federal Register Notice. In that Notice, the sale, distribution
and use of calcium arsenate, including any exiting stocks provision, was
prohibited after August 1, 1988. It was noted in that Federal Register
Notice that most registrations had been either suspended or voluntarily
cancelled before the 1988 cancellation Notice. It is believed all
treated commodities have passed through channels of trade. Thus there
would be no seizure of legally treated goods.
No economic impact is expected as a result of cancellation of these
uses since it is estimated that there has been no use for several years.
VII. CONTACT PERSON
Special Review and Reregistration Division (H7508C),
Office of Pesticide Programs,
Environmental Protection Agency,
401 M St., SW.,
Washington, DC 20460.