What is Guthion?

Guthion is the common name of an organophosphorus insecticide. It is a formulation that includes the active ingredient of azinphos-methyl.  The molecular formula for azinphos-methyl is C₁₀H₁₂N₃O₃PS_2. Pure guthion is a colourless to white odourless crystalline solid. Technical-grade guthion is a cream to yellow-brown granular solid. It does not occur naturally in the environment.

What is Guthion used for?

Guthion has been used on a variety of orchard fruits, cotton, almonds, sugarcane, and other crops; many of these uses have been cancelled, and all remaining uses are scheduled to be phased out.

In the Environment

Release: Guthion can be released during production and use as a pesticide.

Distribution: Found in all environmental compartments without a specific tendency to partition.

Persistence: Not highly persistent; has moderate to low mobility in soil and sediment.

Degradation: In air, Guthion degrades by photolysis and reaction with hydroxyl radicals (half-life of a few hours).

Surface Water/Soil: Biodegradation, photolysis, and hydrolysis occur, with a half-life of 3-50 days in water and 32-150 days in soil.

Bioaccumulation: Not expected to bioconcentrate or bioaccumulate.

Sources & Routes of Exposure

Sources of Exposure

• Food: Main source through consumption of treated foods, like apples, pears, peaches, and cherries.
• Air: Near orchards or crops where Guthion is used.
• Workplace: Agricultural workers like pesticide applicators and fruit pickers may have higher exposure, along with their families (residues on clothes or items).
• Children: May be exposed through soil in treated areas, especially through hand-to-mouth activity.

Routes of Exposure

• Inhalation: Main route for workers during production, handling, and application.
• Oral: Main route for the general public through food and water.
• Dermal: Main route for workers during handling and application.

Health Effects

Acute Health Effects

• Symptoms: Rapid and potentially fatal organophosphate poisoning (headache, sweating, nausea, vomiting, diarrhea, muscle twitching, and possible death).
• Respiratory: Irritates lungs, can cause pulmonary edema (fluid in lungs), a medical emergency.

Chronic Health Effects

• Nervous System: Repeated exposure can damage nerves, causing weakness, "pins and needles," and poor coordination.
• Mental Health: May lead to personality changes like depression, anxiety, or irritability.

Cancer Hazard

• Unknown: Guthion’s carcinogenicity in humans is not confirmed. Studies on animals were inconclusive.

Reproductive Effects

• Unknown: No evidence of reproductive impact in humans or animals.

Safety

First Aid Measures

• Eyes: Rinse with water for 15-20 minutes. Call a physician or poison control.
• Skin: Rinse with water for at least 15 minutes. Remove contaminated clothing. Seek medical help.
• Ingestion: Call a poison control centre immediately. Rinse mouth and give water in small sips. Do not induce vomiting unless advised by a professional.
• Inhalation: Move to fresh air. Call 911 if not breathing and administer artificial respiration. Seek medical help.
• Physician Notes: Guthion is a cholinesterase-inhibiting pesticide. Treat with atropine sulfate in large doses; 2-PAM may also be used. Monitor for pulmonary edema.

Exposure Controls & Personal Protection

General Controls

• Follow label instructions and train employees on safe use.
• Follow the manufacturer's instructions for cleaning PPE. If not provided, wash with detergent and warm water. Keep PPE separate from other laundry.

Engineering Controls

• Maintain exposure levels below limits using general and local ventilation.

Personal Protective Equipment (PPE)

• Eye Protection: Use tightly fitting safety goggles.
• Hand Protection: Chemical-resistant nitrile rubber gloves.
• Body Protection: Wear long-sleeved shirts, long pants, shoes, and socks.
• Respiratory Protection: Use NIOSH-approved respirators as required based on airborne concentrations.

Regulation

United States

OSHA: The Occupational Safety & Health Administration has established a legal airborne permissible exposure limit (PEL) for guthion of 0.2 mg/m³ averaged over an 8-hour workshift.

NIOSH: The National Institute for Occupational Safety & Health has set a recommended airborne exposure limit for guthion of 0.2 mg/m³ averaged over a 10-hour workshift.

ACGIH: The American Conference of Governmental Industrial Hygienists has set a recommended airborne exposure limit for guthion of 0.2 mg/m³ averaged over an 8-hour workshift.

EPA: The Environmental Protection Agency has established tolerances for guthion residues that range from 0.2 to 5 parts per million in raw agricultural commodities.

Australia

Safe Work Australia: Safe Work Australia has set a Time Weighted Average (TWA) concentration for guthion of 0.2 mg/m³ averaged over an 8-hour workshift.