Parathion

Organophosphate insecticide

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Parathion, also known as ethyl parathion, is an organophosphate insecticide and acaricide that was widely used in the past for agricultural purposes. It is a highly toxic compound and is classified as a cholinesterase inhibitor, which means it disrupts the normal function of the nervous system by inhibiting the enzyme acetylcholinesterase.

Chemical Properties

Parathion is a phosphorothioate with the chemical formula C₁₀H₁₄NO₅PS. It is a yellow to brown liquid with a faint odor and is soluble in most organic solvents.

Mechanism of Action

Parathion exerts its toxic effects by inhibiting the enzyme acetylcholinesterase, which is responsible for breaking down the neurotransmitter acetylcholine in the synaptic cleft. This inhibition leads to an accumulation of acetylcholine, resulting in continuous stimulation of muscles, glands, and central nervous system receptors. The overstimulation can cause muscle paralysis, respiratory failure, and death.

Uses

Parathion was primarily used as an insecticide on a variety of crops, including cotton, rice, wheat, fruits, nuts, and vegetables. Its effectiveness in controlling a wide range of pests made it a popular choice among farmers.

Toxicity and Safety

Parathion is extremely toxic to humans and other mammals. Exposure can occur through inhalation, ingestion, or dermal contact. Symptoms of parathion poisoning include headache, dizziness, nausea, vomiting, abdominal cramps, sweating, salivation, muscle twitching, and convulsions.

Treatment

The primary treatment for parathion poisoning involves the administration of atropine and pralidoxime. Atropine acts as an antagonist to acetylcholine, while pralidoxime reactivates acetylcholinesterase.

Environmental Impact

Parathion is highly toxic to wildlife, particularly birds and aquatic organisms. Its use has been restricted or banned in many countries due to its environmental persistence and potential to cause ecological harm.

Regulation

Due to its high toxicity, the use of parathion has been heavily regulated. In the United States, the Environmental Protection Agency (EPA) has classified parathion as a restricted use pesticide, meaning it can only be applied by certified applicators. Many countries have banned its use altogether.

Related pages

• Organophosphate poisoning
• Acetylcholinesterase inhibitor
• Pesticide regulation