Dichlorvos (2,2-dichlorovinyl dimethyl phosphate, commonly abbreviated as an DDVP) is an organophosphate widely used as an insecticide to control household pests, in public health, and protecting stored products from insects. The compound has been commercially available since 1961 and has become controversial because of its prevalence in urban waterways and the fact that its toxicity extends well beyond insects. Since 1988, dichlorvos cannot be used as a plant protection product in the EU.

Use

Dichlorvos is effective against mushroom flies,

aphid Aphids are small sap-sucking insects and members of the superfamily Aphidoidea. Common names include greenfly and blackfly, although individuals within a species can vary widely in color. The group includes the fluffy white woolly aphids. A t ...

s, spider mites, caterpillars,

thrips Thrips (order Thysanoptera) are minute (mostly long or less), slender insects with fringed wings and unique asymmetrical mouthparts. Different thrips species feed mostly on plants by puncturing and sucking up the contents, although a few are ...

, and whiteflies in greenhouses and in outdoor crops. It is also used in the milling and grain handling industries and to treat a variety of

parasitic worm Parasitic worms, also known as helminths, are large macroparasites; adults can generally be seen with the naked eye. Many are intestinal worms that are soil-transmitted and infect the gastrointestinal tract. Other parasitic worms such as sc ...

infections in animals and humans. It is fed to livestock to control

botfly Botflies, also known as warble flies, heel flies, and gadflies, are a family of flies known as the Oestridae. Their larvae are internal parasites of mammals, some species growing in the host's flesh and others within the gut. '' Dermatobia hom ...

larvae in manure. It acts against insects as both a contact poison and an ingested poison. It is available as an aerosol and soluble concentrate. It is also used in pet

flea collar An animal collar is a device that attaches to the neck of an animal to allow it to be harnessed or restrained. Types of collars Pet collar A piece of material put around the neck of certain pet animals, such as dogs, cats, or pigs, for co ...

s and "no-pest strips" in the form of a pesticide-impregnated plastic; this material has been available to households since 1964 and has been the source of some concern, partly due to misuse.

Properties

Dichlorvos is a colourless liquid with aromatic odour. Its density is at , melting point below and a boiling point of at 27

hPa HPA may refer to: Organizations * Harry Potter Alliance, a charity * Halifax Port Authority, Canada * Hamburg Port Authority, Germany * Hawaii Preparatory Academy, a school in Hawaii, US * Health Protection Agency, UK * Heerespersonalamt, the Ger ...

. Dichlorvos is soluble in water.

Mechanism of action

Dichlorvos, like other organophosphate insecticides, acts on acetylcholinesterase, associated with the nervous systems of insects. Evidence for other modes of action, applicable to higher animals, have been presented. It is claimed to damage DNA of insects.

Regulation

The

United States Environmental Protection Agency The Environmental Protection Agency (EPA) is an independent executive agency of the United States federal government tasked with environmental protection matters. President Richard Nixon proposed the establishment of EPA on July 9, 1970; it ...

has reviewed the safety data of dichlorvos several times. In 1995 a voluntary agreement was reached with the supplier, Amvac Chemical Corporation, which restricted the use of dichlorvos in many, but not all, domestic uses, all aerial applications, and other uses. Additional voluntary cancellations were implemented in 2006, 2008, and 2010. Major concerns focus on acute and chronic toxicity and the fact that this pesticide is prevalent in urban waterways. A 2010 study found that each 10-fold increase in urinary concentration of organophosphate metabolites was associated with a 55% to 72% increase in the odds of ADHD in children.

Safety

People can be exposed to dichlorvos in the workplace by breathing it in, skin absorption, swallowing it, and eye contact. The

Occupational Safety and Health Administration The Occupational Safety and Health Administration'' (OSHA ) is a large regulatory agency of the United States Department of Labor that originally had federal visitorial powers to inspect and examine workplaces. Congress established the agenc ...

(OSHA) has set the legal limit (

permissible exposure limit The permissible exposure limit (PEL or OSHA PEL) is a legal limit in the United States for exposure of an employee to a chemical substance or physical agent such as high level noise. Permissible exposure limits are established by the Occupational ...

) for dichlorvos exposure in the workplace as 1 mg/m³ over an 8-hour workday. The

National Institute for Occupational Safety and Health The National Institute for Occupational Safety and Health (NIOSH, ) is the United States federal agency responsible for conducting research and making recommendations for the prevention of work-related injury and illness. NIOSH is part of the C ...

(NIOSH) has set a

recommended exposure limit A recommended exposure limit (REL) is an occupational exposure limit that has been recommended by the United States National Institute for Occupational Safety and Health. The REL is a level that NIOSH believes would be protective of worker safet ...

(REL) of 1 mg/m³ over an 8-hour workday. At levels of 100 mg/m³, dichlorvos is

immediately dangerous to life or health The term immediately dangerous to life or health (IDLH) is defined by the US National Institute for Occupational Safety and Health (NIOSH) as exposure to airborne contaminants that is "likely to cause death or immediate or delayed permanent advers ...

(IDLH).

Effects on humans

Since it is an

acetylcholinesterase inhibitor Acetylcholinesterase inhibitors (AChEIs) also often called cholinesterase inhibitors, inhibit the enzyme acetylcholinesterase from breaking down the neurotransmitter acetylcholine into choline and acetate, thereby increasing both the level and ...

, symptoms of dichlorvos exposure include weakness, headache, tightness in chest, blurred vision, salivation, sweating, nausea, vomiting, diarrhea, abdominal cramps, eye and skin irritation,

miosis Miosis, or myosis (), is excessive constriction of the pupil.Farlex medical dictionary
citing: ...

(pupil constriction), eye pain, runny nose,

wheezing A wheeze is a continuous, coarse, whistling sound produced in the respiratory airways during breathing. For wheezes to occur, some part of the respiratory tree must be narrowed or obstructed (for example narrowing of the lower respiratory tract ...

laryngospasm Laryngospasm is an uncontrolled or involuntary muscular contraction (spasm) of the vocal folds. The condition typically lasts less than 60 seconds, but in cases partial blocking it may last 20 to 30 minutes and hinder inspiration, while exhala ...

, cyanosis,

anorexia Anorexia nervosa, often referred to simply as anorexia, is an eating disorder characterized by low weight, food restriction, body image disturbance, fear of gaining weight, and an overpowering desire to be thin. ''Anorexia'' is a term of Gre ...

, muscle fasciculation, paralysis, dizziness,

ataxia Ataxia is a neurological sign consisting of lack of voluntary coordination of muscle movements that can include gait abnormality, speech changes, and abnormalities in eye movements. Ataxia is a clinical manifestation indicating dysfunction of ...

, convulsions,

hypotension Hypotension is low blood pressure. Blood pressure is the force of blood pushing against the walls of the arteries as the heart pumps out blood. Blood pressure is indicated by two numbers, the systolic blood pressure (the top number) and the dia ...

(low blood pressure), and

cardiac arrhythmia Arrhythmias, also known as cardiac arrhythmias, heart arrhythmias, or dysrhythmias, are irregularities in the heartbeat, including when it is too fast or too slow. A resting heart rate that is too fast – above 100 beats per minute in adults ...

s. It is also known to affect DNA replication in bacteria.

In popular culture

Dichlorvos is mentioned in John Brunner's science fiction novel ''

The Sheep Look Up ''The Sheep Look Up'' is a science fiction novel by British author John Brunner, first published in 1972. The novel is decidedly dystopian; the book deals with the deterioration of the environment in the United States. It was nominated for th ...

''. One of the book's many vignettes tells of a woman who nearly dies, having taken barbiturates and gone to sleep in a closed room where a fly-killing strip doused with the material was placed.

References

External links

Extension Toxicology Network - Pesticide Information Profiles - Dichlorvos
(last maintained 1996)

Australian Pesticides & Veterinary Medicines Authority Chemical Review Program - Dichlorvos

Material Safety Data Sheet (MSDS) for Dichlorvos
*
BBC News: Insecticide ban amid cancer fears
{{Acetylcholine metabolism and transport modulators Acetylcholinesterase inhibitors IARC Group 2B carcinogens Organochlorides Organophosphate insecticides

Use