Calcium acid methanearsonate is an obsolete herbicide that was used for post-emergence weed control mainly on turf. It is highly soluble in water and is expected to be persistent in soil systems. It has a low avian toxicity but moderately toxic to honeybees. It has a low mammalian toxicity if ingested but is a probably neurotoxin.
Colorless liquid. Odorless.
Calcium acid methanearsonate is commercially produced by neutralising methanearsonic acid with a calcium base such as calcium hydroxide or calcium carbonate. Methanearsonic acid itself is synthesised through the reaction of arsenic acid with formaldehyde, forming the organoarsenic backbone. Once the methanearsonic acid is prepared, it is reacted with the calcium compound under controlled pH and temperature conditions to yield calcium acid methanearsonate as a water-soluble salt. The final product is typically dried and milled into a powder or granule form for use.
Inhibitor of mitochondrial ATP synthase.
Moderately toxic by
intraperitoneal and possibly other routes.
Arsenic compounds are considered to be
poisons. An herbicide. When heated to
decomposition it emits toxic fumes of As.
See also ARSENIC COMPOUNDS and
CALCIUM COMPOUNDS.
Organoarsenic herbicide, and defoliant
used to control a wide variety of broadleaf weeds and
annual grasses, primarily in industrial and residential
environments
UN3280 Organoarsenic compound, liquid, n.o.s.,
Hazard Class: 6.1; Labels: 6.1-Poisonous materials,
Technical Name Required, Potential Inhalation Hazard
(Special Provision 5
Keep this material away from bases, heavy metal salts, strong oxidizers; alkaline materials. Contact
with reducing agents may release toxic arsine gas
Do not discharge into drains
or sewers. Dispose of waste material as hazardous waste
using a licensed disposal contractor to an approved landfill.
Consult with environmental regulatory agencies for guidance on acceptable disposal practices. If allowed,
Incineration with effluent gas scrubbing is recommended.
In accordance with 40CFR165, follow recommendations for
the disposal of pesticides and pesticide containers.
Noncombustible containers should be crushed and buried
under more than 40 cm of soil. Must be disposed properly
by following package label directions or by contacting your
local or federal environmental control agency, or by contacting your regional EPA office. Chemical Treatability of
Arsenic—(1) Concentration Process: Chemical
Precipitation; Chemical Classification: Metal; Scale of
Study: Pilot Scale; Type of Wastewater Used: Domestic
Wastewater 1 Pure Compound; Results of Study: 5 ppm @
4 gpm @ pH 5 7.0. Iron system—90% reduction; low lime
system—80% reduction; high lime system—76% reduction;
(3 coagulant systems were used; Iron system used 45 ppm as
Fe of Fe2(SO4)3 @ pH 5 6.0. Low lime system used 20 ppm
Fe of Fe2(SO4)3 and 260 ppm of CaO @ pH 5 10.0. High
lime system used 600 ppm of CaO @ pH 5 11.5. Chemical
coagulation was followed by multimedia filtration). (2)
Concentration Process: Chemical Precipitation; Chemical
Classification: Metal; Scale of Study: Full Scale Continuous
Flow; Type of Wastewater Used: Domestic Wastewater;
Results of Study: Effluent character (ppb): 2.5, 56% reduction with lime; 3.3, 24% reduction with lime; (lime dose of
350400 ppm as calcium oxide @ pH 5 11.3)
