Chemical Properties
colourless liquid
Uses
Mevinphos is a pesticide used in the protection of crops. Insecticide.
General Description
Pale yellow to orange liquid, with a weak odor. Used as an insecticide and acaricide on vegetables, alfalfa, deciduous fruits and nuts.
Air & Water Reactions
Hydrolyzes rapidly as MEVINPHOS dissolves in water.
Reactivity Profile
Organophosphates, such as MEVINPHOS, are susceptible to formation of highly toxic and flammable phosphine gas in the presence of strong reducing agents such as hydrides. Partial oxidation by oxidizing agents may result in the release of toxic phosphorus oxides.
Health Hazard
MEVINPHOS is super toxic; the probable oral lethal dose for humans is less than 5 mg/kg, or a taste (less than 7 drops) for a 150-lb. person. It has direct and immediate effects whether it is swallowed, inhaled, or absorbed through the skin.
Fire Hazard
Fire may produce irritating or poisonous gases. Runoff from fire control may give off poisonous gases and also cause pollution. When heated to decomposition, MEVINPHOS emits toxic fumes of phosphorus oxides. Avoid strong oxidizers. Avoid temperatures above 77-86F, sources of heat, fire, free flames or spark-generating equipment.
Hazard
Toxic by ingestion, inhalation, and skinabsorption; use may be restricted; cholinesteraseinhibitor. Questionable carcinogen.
Potential Exposure
Those engaged in the manufacture,
formulation, and application of this super toxic contact and
systemic insecticide and acaricide.
First aid
If this chemical gets into the eyes, remove any
contact lenses at once and irrigate immediately for at least
15 minutes, occasionally lifting upper and lower lids. Seek
medical attention immediately. If this chemical contacts the
skin, remove contaminated clothing and wash immediately
with soap and water. Speed in removing material from skin
is of extreme importance. Shampoo hair promptly if contaminated.
Seek medical attention immediately. If this
chemical has been inhaled, remove from exposure, begin
rescue breathing (using universal precautions, including
resuscitation mask) if breathing has stopped and CPR if
heart action has stopped. Transfer promptly to a medical
facility. When this chemical has been swallowed, get medical
attention. Give large quantities of water and induce
vomiting. Do not make an unconscious person vomit.
Shipping
UN3018 Organophosphorus pesticides, liquid,
toxic, Hazard Class: 6.1; Labels: 6.1-Poisonous materials.
UN2783 Organophosphorus pesticides, solid, toxic, Hazard
Class: 6.1; Labels: 6.1-Poisonous material.
Incompatibilities
Decomposes in heat (below boiling point
@ 300℃) producing phosphoric acid and phosphorous oxides
fumes. Strong oxidizers may cause release of toxic phosphorus
oxides. Organophosphates, in the presence of strong
reducing agents such as hydrides, may form highly toxic and
flammable phosphine gas. Keep away from alkaline materials.
Corrosive to cast iron, some stainless steels and brass.
Attacks some forms of plastics, rubber and coatings.
Waste Disposal
Mevinphos is 50% hydrolyzed
in aqueous solutions at an unspecified temperature in
1.4 hours at pH 11, 35 days at pH 7; and 120 days at pH 6.
Thermal decomposition is rapidly accomplished by lime
sulfur. Mevinphos may also incinerated. In accordance with
40CFR165, follow recommendations for the disposal of
pesticides and pesticide containers. 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.
Definition
ChEBI: Mevinphos is a dialkyl phosphate and an organophosphate insecticide. It has a role as an EC 3.1.1.7 (acetylcholinesterase) inhibitor, an acaricide, an agrochemical and an avicide. It is functionally related to a methyl 3-hydroxybut-2-enoate.
Agricultural Uses
Insecticide, Acaricide: Mevinphos is an organophosphate insecticide used
to control a broad spectrum of insects, including aphids,
grasshoppers, leafhoppers, cutworms, caterpillars, and
many other insects on a wide range of field, forage, vegetable,
and fruit crops. It is also an acaricide that kills or
controls mites and ticks. It acts quickly both as a contact
insecticide, acting through direct contact with target pests,
and as a systemic insecticide which becomes absorbed by
plants on which insects feed. Not approved for use in EU
countries. Not registered for use in the U.S.
Trade name
AI3-22374®; APAVINPHOS®; CASWELL
No. 160B®; CENTURY-CIDE®[C]; COMPOUND
2046®; DURHAM®[C]; EXCELCIDE®[C]; GESFID®;
GESTID®; PD 5®; HELENA PHOSDRIN®[C]
Environmental Fate
Plant. In plants, mevinphos is hydrolyzed to phosphoric acid dimethyl ester, phosphoric
acid and other less toxic compounds (Hartley and Kidd, 1987). In one day, the compound
is almost completely degraded in plants (Cremlyn, 1991). Casida et al. (1956) proposed
two degradative pathways of mevinphos in bean plants and cabbage. In the first degradative
pathway, cleavage of the vinyl phosphate bond affords methylacetoacetate and acetoacetic
acid which may be precursors to the formation of the end products dimethyl phosphoric
acid, methanol, acetone and carbon dioxide. In the other degradative pathway, direct
hydrolysis of the carboxylic ester would yield vinyl phosphates as intermediates. The halflife
of mevinphos in bean plants was 12 hours (Casida et al., 1956). In alfalfa, the halflife
was 17 hours (Huddelston and Gyrisco, 1961).
Chemical/Physical. The reported hydrolysis half-lives of cis-mevinphos and transmevinphos
at pH 11.6 are 1.8 and 3.0 hours, respectively (Casida et al., 1956). The
volatility half-lives for the cis and trans forms at 28°C were 21 and 24 hours, respectively
(Casida et al., 1956). Worthing and Hance (1991) reported that at pH values of 6, 7, 9 and
11, the hydrolysis half-lives were 120 days, 35 days, 3.0 days and 1.4 hours, respectively
(Worthing and Hance, 1991).
Emits toxic phosphorus oxide fumes when heated to decomposition (Lewis, 1990).
storage
Color Code—Blue: Health Hazard/Poison: Storein a secure poison location. Prior to working with thischemical you should be trained on its proper handling andstorage. Store in tightly closed containers in a cool, wellventilated area away from oxidizers.
Toxicity evaluation
Acute oral LD50 for rats is 3–12 mg/kg.Inhalation LC50 (1 h) for rats is 0.125 mg/L air. No
ill effects were observed in rats receiving 4 mg/kg diet
(0.2 mg/kg/d) for 2 yr. ADI is 1.5 μg/kg b.w. In comparison
with the Z-isomer, E-mevinphos is a more effective
insecticide and is detoxified more quickly in plants but
more slowly in animals.
