Paraquat - A Widely Used Toxic Herbicide

What Is Paraquat?

Paraquat is one of the most widely and commonly used herbicides for controlling weeds in many agricultural and non-agricultural practices. It is also used as a defoliant (chemicals used to kill unwanted leaves) on crops, like cotton, before harvest. Paraquat is a safe and effective herbicide if used in the correct direction as indicated. However, for several reasons, suicide with agrochemicals is a very devastating and unfortunate social problem, particularly in a few developed countries.

Paraquat, in 1961, was produced for commercial purposes. It is commonly used as a herbicide worldwide, and many cases have been reported of accidental ingestion of paraquat as an agrochemical. Paraquat poisoning is not the only common problem seen in the United States. It is a major medical problem in many parts of Asia and other areas of the world. It is also reported that more than 70 percent of people who ingest the chemical mistakenly lead to paraquat poisonings which result in life-threatening conditions and even death.

Paraquat is the active ingredient of Gramoxone, used in agricultural land to control weeds and grasses and all the unwanted plants which can harm the crop and land fertility. It is restricted in the market to use as a pesticide due to acute toxicity and is only for use by certified applicators who can buy and use it. The product is toxic to humans and wildlife, is mildly corrosive to aluminum, and produces hydrogen gas which may form a highly combustible gas mixture in the presence of aluminum.

What Is the Mechanism of Paraquat Poisoning?

The severity of paraquat poisoning depends on the amount, route, and duration of exposure. It also depends on the person's immunity and health. Paraquat can cause damage when it comes into contact with the mouth, stomach, or intestinal lining. After the paraquat enters the body, it can spread to all the body parts. Paraquat causes toxic chemical reactions in many internal organs, such as the lungs, the liver, and the kidneys.

What Are the Signs the Symptoms Associated With Paraquat Poisoning?

Paraquat poisoning leads to certain signs and symptoms after an individual intakes a large amount of paraquat. The individual will be immediately likely to have pain and swelling in the mouth and throat. It can lead to some serious illnesses following ingestion, such as gastrointestinal symptoms like nausea, vomiting, abdominal pain, and diarrhea (which may become bloody). Severe gastrointestinal symptoms may result in dehydration, electrolyte abnormalities, and hypotension (low blood pressure).

Ingestion of a small amount of paraquat may result in the following adverse effects.

• Heart failure.

• Kidney failure.

• Liver failure.

• Lung scarring.

Ingestion of large amounts of paraquat can result in the following effects.

• Acute kidney failure.

• Confusion.

• Coma.

• Fast heart rate.

• Injury to the heart.

• Liver failure.

• Lung scarring (evolves more quickly when small to medium amounts have been ingested).

• Muscle weakness.

• Pulmonary edema (accumulation of fluid in the lungs).

• Respiratory failure (breathing difficulty).

• Seizures.

What Are the Treatment Modalities for Paraquat Poisoning?

In most cases, drinking paraquat is the most common reason for paraquat poisoning. The treatment involves removing the poison from the body and treating other symptoms. Some paraquat poisoning treatments may include:

• Fuller’s earth binds and removes it from the body.

• Activated charcoal helps to remove paraquat and stop it from being absorbed.

• N-acetyl-cysteine or other antioxidants help the liver detoxify.

• Fluids through an IV needle.

• Medications to improve breathing.

• Medications to raise blood pressure.

• Ventilator to improve breathing.

• Kidney dialysis helps the kidneys filter blood.

• Sometimes it is suggested that using oxygen therapy as a treatment can also help a lot, but oxygen therapy has its own drawbacks, so it can be avoided.

If a person spills paraquat on the clothes or skin or gets it in their eyes, they should:

• Remove their clothes right away and avoid using the same clothes to rub their face.

• Quickly wash the body with lots of soap and water.

• Avoid contact with the eyes.

• Rinse the eyes with plain water.

• Go to a hospital right away.

How Is Paraquat Poisoning Treated?

At the hospital, the doctor's first focus is to eliminate the paraquat from the system.

• If a person is exposed to paraquat, activated charcoal is given to take orally or through a nasal tube. This may help absorb the chemical and reduce the amount that is taken up by the body.

• If the paraquat poisoning is more advanced, the doctors may order a hemoperfusion. This procedure filters blood through charcoal to remove the paraquat from the system, especially from the lungs.

• The affected person will also be given fluids and electrolytes through an IV route to keep the body hydrated. If breathing becomes labored or difficult, the patient will be given respiratory support, such as oxygen therapy.

• Doctors will continue to test the blood and urine and continuously monitor vital signs. Doctors may perform a chest X-ray or CT scan (computed tomography) to evaluate lung injury. They may also be attached to a heart monitor or order an electrocardiogram (ECG) to evaluate the heart’s functioning.

• As symptoms arise, the doctors will administer medications and perform medical interventions to address them. This may include anti-vomiting and anti-seizure medications.

Conclusion:

Paraquat is a commonly used herbicide, and ingestion of the chemical can result in serious conditions. There are various rules and regulations for purchasing and using the paraquat to avoid unwanted circumstances. It is often not possible to reverse the damage caused by the exposure, and it can lead to long-term consequences. However, early diagnosis and treatment can help to avoid permanent side effects of the poisoning. Unfortunately, paraquat is highly toxic, and there is no cure or antidote for it.