StatM Wit* of Ptitieida ind Toxic Substinm
Environment*! Protection Offict of Ptttiad* Proa.r«m* (TS-766C)
Agency Wahington. DC 20460
c/EPA Pesticide
Fact Sheet
Name Of Chemical: Calcium arsenate
Reason for Issuance: special review
Date Issued: Decertber 1986
FacYSheet Number: 111
1. DESCRIPTION OF CHEMICAL
Common Name: Calcium Arsenate
Chemical Name: Calcium Orthoarsenate - Ca3(As04>2
Trade Name: Turf-Cal
EPA Shaughnessy Code: 013501
Chemical Abstracts Service (CAS) Number: 7778-44-1
Year of Initial Registration:
Pesticide Type: Herbicide
Chemical Family: Inorganic Arsenicals
U.S. and Foreign Producers: Security Chemical Co.
2.' USE PATTERNS AND FORMULATIONS
Calcium arsenate is currently used as a herbicide on 18%
of U.S. golf courses for controlling Poa annua, crabgrass,
and other .annual grasses. It has also been used as a crop
herbicide and an insecticide; however, these uses are
considered to be inactive.
0 Methods of Application: The flowable (liquid suspension)
fotmulation is generally applied by ground boom. Products
which are currently suspended include application by hand-
held sprayer or broadcast spreader.
0 Application Rates: Turf- 4.5 Ib ai/A
Types of Formulations: The remaining active registered
product is a flowable (liquid suspension). Products which
are currently suspended include granular, wettable powder,
and wettable powder/dust formulations.
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3. SCIENCE FINDINGS
Che”ti’ al Characteristics
Calcium arsenate is a pentavalent form of inorganic arsenic.
It normally exists as a colorless amorphic powder with no
discernible odor. Calcium arsenate contains 38% arsenic and
is slightly soluble in water and soluble in dilute acids.
The melting point of calcium arsenate is 1455°C the
density is 3.62 and the molecular weight is 398.08.
° 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 mutagertic.
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 calcium 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 cardiovascular reactions
are also known to occur following oral exposure to arsenic.
o Environmental Characteristics: The environmental fate of
calcium 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
calcium arsenate is not predicted to leach significantly.
O Ecological Characteristics: Calcium arsenate is moderately
toxic to birds, slightly toxic to fish and moderately toxic
to aquatic invertebrate species.
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Metabolism : The metabolism of inorganic arsenic compounds
in animals is well known. The pentavalent form, such as
calcium 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.
4. SUMMARY OF REGULATORY POSITION AND RATIONALE
The Agency is proposing to cancel all existing registrations
of calcium arsenate, with the exception of the flowable formulation
for use on turf. 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 toxicological risks from all non—
wood uses of calcium arsenate, except the aformentioned use on
turf, outweigh the limited benefits. The flowable formulation
for use on turf is being deferred pending further evaluation by
EPA’s Risk Assesment Forum of the carcinogenic potency of inorganic
arsenic from dermal and dietary exposure. -
Benefits Analysis : No economic impact is expected as a result
of cancellation of these uses. Viable alternatives are
available.
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
rereg istrat ion.
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