Occupational Exposure to Organophosphates

Occupational Exposure to Organophosphates
Page content

Organophosphate poisoning is a TRUE EMERGENCY. If you think somebody has been exposed to organophosphates, note the type of product involved and activate emergency medical services immediately. To find your local POISON CONTROL CENTER in the United States only, enter your state into the form at the American Association of Poison Control Centers website.

To identify the SIGNS of organophosphate poisoning, remember the acronym SLUDGE.

  • Salivation - excessive salivation
  • Lacrimation - excessive tearing/shedding of tears
  • Urinary incontinence - uncontrolled urination
  • Defecation - lack of bowel control
  • Gastrointestinal motility (diarrhea)
  • Emesis - vomiting

The acute toxicity of organophosphate affects both professionals and amateurs, so if you even suspect an exposure, CALL. It’s better to be safe than to be sorry.

What are Organophosphates?

Approximately 900 types of pesticides are used in the United States. Of these, some are based on organophosphates.

Organophosphates are among a group of chemicals used to kill insects in homes, agriculture, and industries. They have become the most commonly used pesticides after organochloride insecticides.

Development of Organophosphates

Organophosphates were developed to target the unwanted effects of certain species. They were also developed in the 1940s in terms of highly toxic warfare agents like Sarin and Tabun. VX “nerve gas” was also created in the UK in the 1950s, but the first commercial product of organophosphate was Parathion, developed to replace DDT.

This group of chemicals was originally referred to as “nerve agents.” Now, these insecticides have been modernized up to a great extent.

Chemical Structure of Organophosphates

Actually, organophosphates are esters of phosphoric acid. They are formed by the esterification of phosphoric acid by the attachment of organic groups to phosphorous through oxygen linkers. Phosphoric acid is a triprotic acid; therefore, it forms tri-esters during its esterification.

The image given below indicates the structure of organophosphates. (Please click to enlarge.)

There are three important points regarding their structure:

  • A terminal oxygen attached to phosphorous by a double bond.
  • Two lipophilic groups bonded to the phosphorous.
  • A leaving group bonded to the phosphorus. Usually, a halide is used as a leaving group.

How Organophosphates Work

The work of organophosphates is to kill insects by inhibiting their brain and nervous system. The mechanism of these insecticides is developed to block the enzyme acetyl-cholinesterase that causes the insect’s death by damaging the nervous and respiratory system.

Although they are very useful for killing insects, they may harm the brains and nervous system of animals and humans too, and this is the main disadvantage of these insecticides.

Organophosphate Poisoning: Disadvantage of Excess Use of Organophosphate Insecticides

Organophosphates are used in various industries as solvents, plasticizers, and EP additives. They are very harmful for animals and humans. They are very toxic and likely to cause several effects including death. They are a potent nerve agent and can inhibit the action of acetylcholinesterase present in nerve cells. They are often used for suicides in agriculture areas, unfortunately. The other bad effect of these insecticides comes with chronic exposure, which kills 300,000 people every year, usually poorer people living near chemical factories.

Effects of Organophosphate

Some effects of organophosphates are given below:

  • The organophosphate insecticide chlorpyrifos is used for fruits and vegetables, which reduces physical coordination and causes ADHD in children.
  • According to a study, organophosphate exposure increases the risk of Alzheimer’s disease.
  • Exposure to agricultural use of organophosphates causes depression.
  • Occupational exposure to organophosphates causes a cardiac effect that is responsible to decreased cardiac output.
  • They produce teratogenic effects in animals.
  • During agriculture use, your eyes may get harmed by these insecticides.

The level of effect of these chemicals depends upon:

  • The type of the chemical
  • The concentration of exposure
  • The length of the time and the method of exposure

Toxicity in Organophosphates Insecticides

Organophosphates are generally acutely toxic. They are divided into three groups with respect to their toxicity.

  • The members of first group such as chlorfenvinphos have LD50 in the range 1-30 mg/kg.
  • The second group has LD50 of the range 30-50 mg/kg. Dichlorvos is the example of the second group.
  • The third and last group has a range of 60-1,300 mg/kg LD50, for example malathion.

Why Organophosphate Poisoning Takes Place

Here are some causes that tend to organophosphate poisoning

  • Eating or drinking something with some organophosphate in it is the most important cause of organophosphate poisoning.
  • Inhaling the air that has some organophosphates contents in it may cause you organophosphate poisoning.
  • The direct contact of your skin with any organophosphate is also a cause of organophosphate poisoning.

Symptoms of Organophosphate Exposure

  • Feeling sick
  • Headache
  • Weakness and tiredness
  • Sweating and salivation
  • Vomiting
  • Problem of stomach cramps
  • Pupils of eyes becomes very small
  • Blurred vision
  • Breathing becomes bubbly
  • Unconsciousness

Organophosphates have both advantages and disadvantages. They are useful in certain areas and harmful for our health, too. If you feel these symptoms, go for treatment as soon as possible.


Reference- www.pan-uk.org



Image- Organophosphate structure- wikimedia.org