In News:

• In a landmark ruling, a Thiruvananthapuram court sentenced a 24-year-old woman to death for the murder of her boyfriend by poisoning him with paraquat, a highly toxic herbicide.
• The incident, which occurred in 2022, has brought the spotlight back on paraquat's widespread availability, extreme toxicity, and the lack of regulatory enforcement in India.

What is Paraquat?

• Paraquat, chemically known as paraquat dichloride or methyl viologen, is one of the most widely used herbicides globally.
• It is primarily used for:
  • Weed control
  • Crop desiccation, especially in crops like cotton before harvest
• Despite its toxicity, India and the United States continue to permit its usage, unlike over 70 countries, including China, Brazil, and the European Union, which have banned it.

WHO Classification

• The World Health Organization (WHO) classifies paraquat as a Category 2 chemical, meaning it is moderately hazardous and irritating to the skin and eyes.
• It has a narrow margin between a safe and lethal dose, making accidental or intentional poisoning common and often fatal.

Routes and Effects of Exposure

• Ingestion is the most common method of poisoning.
• It may also occur through inhalation or skin contact, especially if the exposure is prolonged or the skin is broken.

Symptoms Vary by Dosage and Exposure Time:

Exposure Level                        Symptoms and Organ Damage

Small Quantity                       Gradual damage to lungs, liver, kidneys, and heart over days/weeks

Large Quantity                       Immediate symptoms such as:

• Acute kidney failure
• Liver and heart failure
• Seizures
• Respiratory failure
• Severe abdominal pain
• Bloody diarrhea
• Nausea
• Mouth and throat swelling |

Treatment and Challenges

• No known antidote exists for paraquat poisoning.
• Treatment options include:
  • Immunosuppressive therapy
  • Charcoal hemoperfusion (a blood-purification technique)
• However, these treatments offer limited efficacy, especially in cases of large-dose ingestion.

Regulatory and Public Health Implications in India

• Despite paraquat’s well-documented toxicity, it remains:
  • Legally available in India
  • Easily accessible in rural markets
• The lack of regulation increases the risks of:
  • Occupational exposure
  • Accidental poisoning
  • Use in crimes or suicides