Description
Dichlorvos is a famous organophosphate insecticide that widely used to control household pests, in public health, and protecting stored product from insects. The compound has been commercially available since 1961. It can be used for the treatment of mushroom flies, aphids, spiders, caterpillars, thrips and whiteflies in fruits and crops as well as many kinds of parasitic worm in dogs and livestock as well as human beings. Its primary target, like other kinds of organophosphate insecticide, is the acetylcholinesterase. Therefore, it blocks the normal function of the nervous systems of insects. However, its application has been under controversy due to its potential toxicity on human beings and animals. Exposure to it can cause multiple adverse reactions of respiratory, cardiovascular, eye, skin, and muscle, nervous and so on. It is also known that Dichlorvos is extremely toxic to fishes, being capable of impairing fish health through impairing normal metabolism and even leading to death.
References
Das, Suchismita. "A review of Dichlorvos toxicity in fish." Current World Environment 8.1(2013):143-149.
Booth, Ed, and E. B. Jones. "Review of the in vitro and in vivo genotoxicity of dichlorvos. " Regulatory Toxicology & Pharmacology 49.3(2007):316.
Ero?lu HE. "Toxic nuclear effects of the organophosphorus insecticide Dichlorvos (DDVP) in human peripheral blood lymphocytes." Acta Biologica Hungarica 60.4(2009):409-16.
Description
Cases of sensitization to dichlorvos have been seen in
chrysanthem growers, horticulturists, technicians and
in a chemist.
Description
Dichlorvos is an organophosphate insecticide and inhibitor of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE; IC
50s = 269 and 44 nM, respectively). It also binds to the M
2 muscarinic receptor in rat heart homogenates. Dichlorvos is lethal to 4-week old German cockroach (
B. germanica) nymphs (LD
50 = 0.108 μg per insect) and silkworms (
B. mori) in third instar (LC
50 = 6.63 mg/L) after 24 hours. It is lethal to zebrafish (
D. rerio) embryos (LC
50 = 39.75 mg/L after 24 hours) and decreases swimming activity of larvae 6 days after fertilization when administered at a concentration of 25 mg/L in tank water. Dichlorvos (150 ppm for 80 weeks) also increases the incidence of benign and malignant neoplasms in male rats from 47 to 88% as compared to controls.
Chemical Properties
Dichlorvos is available as an oily colourless to amber liquid with an aromatic chemical odour. It is slightly soluble in water but soluble in kerosene, ethanol, chloroform, and acetone and miscible with alcohol, aromatic and chlorinated hydrocarbon solvents, aerosol propellants, and other non-polar solvents. Dichlorvos in contact with strong acids or alkalis undergoes decomposition and releases hazardous products toxic gases and vapours such as phosphorus, chlorinated oxides, and carbon monoxide.
Chemical Properties
Dichlorvos is a colorless to amber liquid with
a mild aromatic odor.
Chemical Properties
Dichlorvos occurs as an oily colorless to amber liquid with slight solubility in water. It has
an aromatic chemical odor. Dichlorvos is used as an agricultural insecticide for the control
of crop pests, such as fl ies, aphids, spider mites, caterpillars, and thrips, and also pests in
store grains, and parasitic worms in animals, in fl ea collars for dogs. Occupational workers
and the general public can be exposed to dichlorvos while working with the manufacture,
formulation, and application on agricultural crops, and when used as a fumigant, and as
pest strips. Human exposures also occur through food contamination.
Physical properties
Colorless to yellow liquid with a mild aromatic odor
Uses
Dichlorvos is used for the control of household and public health
insect pests and the control of sucking and chewing pests in a wide range
of crops. It is used as a veterinary anthelmintic, as an ectoparasiticide on
fish and domestic pets and a vapour phase domestic insecticide as well for
the control of phorid and sciarid flies in mushroom compost.
Uses
Cholinesterase inhibitor. Anthelmintic, insecticide.
Uses
Organophosphorus insecticide and fumigant used against flies, mosquitoes and
moths.
Definition
ChEBI: An alkenyl phosphate that is the 2,2-dichloroethenyl ester of dimethyl phosphate.
brand name
Atgard (Boehringer Ingelheim Animal Health); Equigard (Boehringer Ingelheim Animal Health); Equigel (Boehringer Ingelheim Animal Health); TASK Tabs (Boehringer Ingelheim Animal Health).
General Description
An aromatic colorless to amber liquid absorbed in a dry carrier. Denser than water and slightly soluble in water. Toxic by inhalation, skin absorption, absorption, or ingestion. Flash point 175°F or higher. When heated to high temperatures may emit toxic chloride fumes and phosgene gas. Used as a pesticide.
Air & Water Reactions
Slightly soluble in water.
Reactivity Profile
DICHLORVOS MIXTURE is incompatible with strong acids and bases. Dichlorvos is slowly hydrolyzed in acidic media and rapidly hydrolyzed by alkalis. Dichlorvos is corrosive to iron and mild steel. . Organophosphates 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
Exposures to dichlorvos through all routes, namely, oral, dermal, and respiratory,
cause adverse effects to species of laboratory animals, such as rats, mice, and rabbits.
The symptoms of poisoning include perspiration, nausea, salivation, vomiting, diarrhea,
drowsiness, fatigue, headache, and in severe cases, tremors, ataxia, convulsions,
and coma.
Humans exposed to dichlorvos show many symptoms of poisoning that include, but
are not limited to, irritability, confusion, headache, speech diffi culties, sweating, blurred
vision, drowsiness or insomnia, numbness, tingling sensations, incoordination, tremor,
abdominal cramps, diffi culty in breathing or respiratory depression and slow heart beat,
impaired memory concentration, disorientation, and severe depressions.
Health Hazard
Highly toxic, may be fatal if inhaled, swallowed or absorbed through skin. Contact with molten substance may cause severe burns to skin and eyes. Avoid any skin contact. Effects of contact or inhalation may be delayed. Fire may produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may be corrosive and/or toxic and cause pollution.
Health Hazard
Highly toxic by all routes of exposure;exhibits acute, delayed, and chronic poison-ing; cholinesterase inhibitor; signs and symp-toms of exposure are similar to those ofother organophosphates; toxic effects includesweating, twitching of muscle, constrictionof pupils, lacrimation, salivation, tightnessin the chest, wheezing, slurred speech, nau-sea, vomiting, abdominal pain, and diarrhea;high exposure can result in coma, cessationof breathing, and death. Oral LD50 valuein rodents reported in the literature varieswidely from 17 to 80 mg/kg in rat and61–275 mg/kg in mouse.
LC50 inhalation (mouse): 13 mg/m
3 /4 h
LD50 skin (mouse): 206 mg/kg
LD50 oral (wild bird): 12 mg/kg.
Fire Hazard
Combustible material: may burn but does not ignite readily. Containers may explode when heated. Runoff may pollute waterways. Substance may be transported in a molten form.
Agricultural Uses
Insecticide, Acaricide, Nematicide: Dichlorvos is used for insect control in food-storage
areas, green-houses, and barns, and control of insects
on livestock. It is not generally used on outdoor crops.
Dichlorvos is sometimes used for insect control in workplaces
and in the home. Dichlorvos used in pest control
is diluted with other chemicals and used as a spray. It can
also be incorporated into plastic that slowly releases the
chemical. Veterinarians use it to control parasites on pets.
Dichlorvos is effective against mushroom flies, aphids, spider
mites, caterpillars, thrips, and white flies in greenhouse,
outdoor fruit, and vegetable crops. It is used to treat a variety
of parasitic worm infections in dogs, livestock, and humans.
Dichlorvos can be fed to livestock to control botfly
larvae in the manure. It acts against insects as both a contact
and a stomach poison. It is used as a fumigant and has
been used to make pet collars and pest strips. It is available
as an aerosol and soluble concentrate. Not approved for use
in EU countries. A U.S. EPA restricted Use Pesticide
(RUP). Dichlorvos also exists as a breakdown product.
Trade name
ALCO® Dichlorvos; APAVAP®;
ASTROBOT®; ATGARD®; BAY 19149®; BAYER 19149®;
BENFOS®; BIBESOL®; BREVINYL®; BREVINYL
E 50®; CANOGARD®; CEKUSAN®; CYPONA®;
DEDEVAP®; DERRIBAN®; DERRIBANTE®; DES®;
DEVIKOL®; DICLORCAL 50®; DIDIVANE; DIVIPAN®;
DOOM®; DQUIGARD®; DUO-KILL®; DURAVOS®;
ELASTREL®; EQUIGARD®[C]; EQUIGEL®[C];
ESTROSEL®; ESTROSOL®; FECAMA®; FEKAMA®;
FLY-DIE®; FLY FIGHTER®; HERKOL®; INSECTIGAS
D®; KRECALVIN®; LINDAN®; MAFU®; MARVEX®;
MOPARI®; NEFRAFOS®; NERKOL®; NOGOS®; NOPEST®;
NOVOTOX®; NUVA®; NUVAN®; OKO®;
OMS 14®; PANAPLATE®; PHOSVIT®; PRENTOX®;
SD 1750®; SUCHLOR®; SZKLARNIAK®; TAP
9VP®; TASK®; TENAC®; TETRAVOS®; UNIFOS
(PESTICIDE)®; UNITOX®; VAPONA® et al.
[C]; VAPONITE®; VERDICAN®; VERDIPOR®;
VERDISOL®; VINYLOFOS®; VINYLOPHOS®;
WINYLOPHOS®
Contact allergens
Cases of sensitization to this organophosphorus
compound with several commercial names (Benfos,
Brevinyl, Chlorvinphos, DDVP, Equigard, Fly fghte,
Nogos, and Unifos) were occupationally seen in chry-
santhem growers, horticulturists, technicians, and in a
chemist.
Safety Profile
Confirmed carcinogen
with carcinogenic and tumorigenic data.
Poison by ingestion, inhalation, skin contact,
subcutaneous, intravenous, and intraperitoneal routes. Experimental
teratogenic and reproductive effects. Human
mutation data reported. A cholinesterase
inhibitor, it is used in flea (pest) collars for
pets. No neurotoxicity has been observed. It
is very rapidly metabolized and excreted.
When heated to decomposition it emits very
toxic fumes of Cl and POx. See also
PARATHION.
Potential Exposure
A potential danger to those involved
in manufacture, formulation and application of this fumigant insecticide in household, public health and agricultural
uses. Used as an insecticide and as an anthelminthic for
swine and dogs.
Veterinary Drugs and Treatments
Dichlorvos is effective in swine against Ascaris, Trichuris, Ascarops
strongylina and Oesophagostomum spp.
Dichlorvos as a “No Pest Strip” is used as an ectoparasiticide
for
small mammals. It is also used as a premise spray to keep fly populations
controlled.
In horses, dichlorvos is labeled as being
effective for the treatment
and control of bots, pinworms, large and small bloodworms,
and large roundworms, but no systemic equine products are currently
being marketed in the USA.
Dichlorvos was available for use internally in dogs and cats for
the treatment of roundworms and hookworms, but no products
are currently being marketed since newer, safer and more effective
anthelmintics have replaced dichlorvos.
First aid
If this chemical gets into the eyes, remove anycontact lenses at once and irrigate immediately for at least15 min, occasionally lifting upper and lower lids. Seek medical attention immediately. If this chemical contacts theskin, remove contaminated clothing and wash immediatelywith soap and water. Speed in removing material from skinis of extreme importance. Shampoo hair promptly if contaminated. Seek medical attention immediately. If thischemical has been inhaled, remove from exposure, beginrescue breathing (using universal precautions, includingresuscitation mask) if breathing has stopped and CPR ifheart action has stopped. Transfer promptly to a medicalfacility. When this chemical has been swallowed, get medical attention. Give large quantities of water and inducevomiting. Do not make an unconscious person vomit.Medical observation is recommended for 24-48 h following overexposure.
Carcinogenicity
Two epidemiological studies
reporting an association between exposure to dichlorvos
resin strips and childhood cancer were reviewed
by EPA and found to have biases and confounders that
could explain the observed associations. Additional studies
that correct for the control of potential biases and problems of
exposure determination are needed before an association
between dichlorvos and childhood cancer can be established.
Environmental Fate
Biological. When dichlorvos was incubated with sewage sludge for one week at 29°C,
it was converted to dichloroethanol, dichloroacetic acid, ethyl dichloroacetate and an
inorganic phosphate. In addition, dimethyl phosphate formed in the presence or absence
of microorganisms (Lieberman and Alexander, 1983). Dichlorvos degraded fastest in
nonsterile soils and decomposed faster in soils that were sterilized by gamma radiation
than in soils that were sterilized by autoclaving. After one day of incubation, the percent
of dichlorvos degradation that occurred in autoclaved, irradiated and nonsterile soils were
17, 88 and 99, respectively (Getzin and Rosefield, 1968).
Soil. In a silt loam and sandy loam, reported Rf values were 0.79 and 0.80, respectively
(Sharma et al., 1986).
Plant. Metabolites identified in cotton leaves include dimethyl phosphate, phosphoric
acid, methyl phosphate and O-demethyl dichlorvos (Bull and Ridgway, 1969).
Photolytic. Dichlorvos should not undergo direct photolysis since it does not absorb
UV light at wavelengths >240 nm (Gore et al., 1971).
Chemical/Physical. Releases very toxic fumes of phosphorus oxides and chlorine when
heated to decomposition (Sax and Lewis, 1987).
Slowly hydrolyzes in water and in acidic media but is more rapidly hydrolyzed under
alkaline conditions to dimethyl hydrogen phosphate and dichloroacetaldehyde (Capel et
al., 1988; Hartley and Kidd, 1987; Worthing and Hance, 1991). In the Rhine River (pH
7.4), the hydrolysis half-life of dichlorvos was 6 hours (Capel et al., 1988).
Atkinson and Carter (1984) estimated a half-life of 320 days for the reaction of
dichlorvos with ozone in the atmosphere.
Metabolic pathway
The metabolism of dichlorvos has been extensively studied particularly
in mammals. Dichlorvos is rapidly transformed in both environmental
and biological situations via a hydrolytic mechanism to yield
dimethyl phosphate and dichloroacetaldehyde which is further metabolised
to 2,2-dichloroethanol or dechlorinated to glycolic acid. An additional
important route in mammals involves demethylation catalysed
by glutathione-S-methyl transferase to yield methylglutathione and
desmethyldichlorvos.
storage
Color Code—Blue: Health Hazard/Poison: Storein a secure poison location. Prior to working with dichlorvos you should be trained on its proper handling and storage. Store in tightly closed containers in a cool, wellventilated area away from strong acids; strong alkalis.Dichlorvos will attack some forms of mild iron, plastics,rubber, and coatings.
Shipping
UN3018 Organophosphorus pesticides, liquid,
toxic, Hazard Class: 6.1; Labels: 6.1-Poisonous materials
Degradation
Dichlorvos is slowly hydrolysed in water and in acidic media and rapidly
hydrolysed by alkali to dichloroacetaldehyde (2) and dimethyl phosphate
(3) (PM)
Toxicity evaluation
Acute oral LD
50 for rats: ca. 50 mg /kg
Incompatibilities
Contact with oxidizers may cause the
release of phosphorous oxides. Organophosphates are susceptible to formation of highly toxic and flammable phosphine gas in the presence of strong reducing agents such as
hydrideds and active metals. Partial oxidation by oxidizing
agents may result in the release of toxic phosphorus oxides Corrosive to iron, mild steel, some forms of plastics, rubber, and coatings
Waste Disposal
50% hydrolysis is obtained
in pure water in 25 minutes @ 70_x0003_°C and in 61.5 days @
20C. A buffered solution yields 50% hydrolysis (37.5°C) in
301 minutes at pH 8, 462 minutes at pH 7, 620 minutes at
pH 5.4. Hydrolysis yields no toxic residues. Incineration in a
furnace equipped with an afterburner and alkaline scrubber is
recommended as is alkaline hydrolysis followed by soil
burial. 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.
