Disulfoton is a synthetic pesticide used to control a wide variety of insects that attack crops such as grains, vegetables, fruit, nuts, and ornamental plants. It does not occur naturally.
Pure disulfoton is a colourless oil with no odour or taste, while the technical-grade product is dark yellowish with an aromatic smell. It is poorly soluble in water, evaporates slowly into air, and is usually found in hazardous waste sites either in drums or mixed with soil.
Its molecular formula is C₈H₁₉O₂PS₃.
What is Disulfoton used for?
Disulfoton is mainly used in agriculture, including:
Protection of small grains, corn, sorghum, fruit, nut, and vegetable crops
Ornamental and potted plants
Mosquito control in swampy areas
Disulfoton is primarily used in agriculture to protect a variety of crops—including small grains, corn, sorghum, fruits, nuts, and vegetables—against pests by acting as a systemic insecticide and acaricide.
In the Environment
Although once widely applied, the use of disulfoton has declined in recent years due to health and environmental concerns.
Disulfoton enters the environment primarily through spraying or applying granules to crops.
Accidental spills during storage or transport can also release it.
Hazardous waste sites are another significant source of contamination.
In soil and water, disulfoton breaks down through chemical reactions and bacterial activity, but some breakdown by-products can be more toxic than the original chemical.
It binds moderately to soil and does not easily leach into groundwater.
Fish can accumulate disulfoton in their tissues at levels hundreds of times higher than the surrounding water.
Sources & Routes of Exposure
Sources of Exposure
Breathing contaminated air
Drinking contaminated water
Eating contaminated food
Working in industries that manufacture, formulate, or apply disulfoton
Farming activities, especially spraying or re-entering recently treated fields
Use of disulfoton in home gardens
Living near hazardous waste sites containing disulfoton
Children may be exposed by touching or ingesting contaminated soil near these sites.
Routes of Exposure
Inhalation
Ingestion
Skin and/or eye contact
Health Effects
Acute Toxicity
Disulfoton is highly toxic to mammals by all routes of exposure.
Early symptoms: blurred vision, fatigue, headache, dizziness, sweating, tearing, and salivation.
Severe poisoning: nausea, urination, diarrhoea, convulsions, fluid in the lungs, or coma.
Death may occur from respiratory muscle failure or airway constriction.
Ingestion symptoms appear rapidly, while those from skin exposure may be delayed up to 12 hours.
Full recovery takes at least a week; normalisation of cholinesterase enzyme activity may take up to three months.
Chronic Toxicity
Rapidly absorbed through skin.
Inhibits cholinesterase, affecting the nervous system, eyes, and respiratory system.
Long-term effects may include flu-like symptoms, memory issues, anxiety, slower reaction times, and irritability.
Chronic exposure may also lead to cataracts.
Reproductive Effects
High-dose animal studies show reduced pregnancy rates, smaller litter sizes, and liver damage in offspring.
Long-term exposure may cause reproductive issues in humans.
Teratogenic Effects
Animal studies suggest a low likelihood of birth defects in humans.
High doses in rats led to incomplete bone development in foetuses; in rabbits, maternal toxicity (tremors, incoordination, and death) was seen at high doses, but not foetal harm.
Mutagenic Effects
Shown to be mutagenic in bacteria.
Carcinogenic Effects
Long-term studies in rats and mice found no evidence of tumour development.
The EPA has determined that disulfoton is not carcinogenic.
Safety
First Aid Measures
General: Seek medical attention immediately and provide physicians with safety data information if available.
Inhalation: Move the person to fresh air. If not breathing, provide artificial respiration. Seek urgent medical attention.
Skin contact: Wash thoroughly with soap and water. Remove contaminated clothing and take the victim to the hospital. Seek medical attention.
Eye contact: Rinse eyes with plenty of water. Seek medical advice if irritation develops.
Ingestion: Do not give anything by mouth to an unconscious person. Rinse mouth with water and consult a physician immediately.
Exposure Controls and Personal Protection
Engineering Controls
Ensure appropriate ventilation and local exhaust systems to prevent inhalation exposure.
Avoid skin, eye, and clothing contact.
Wash hands after handling and before breaks.
Personal Protective Equipment
Eye/face protection: Safety glasses and a face shield, compliant with NIOSH (US) or EN 166 (EU) standards.
Skin protection: Chemical-resistant gloves meeting EN 374 standards. Inspect gloves before use, follow correct removal techniques, and dispose of safely. Wash and dry hands thoroughly.
Body protection: A complete chemical-resistant protective suit, depending on workplace concentration and risk level.
Respiratory protection:
For routine work: full-face respirator with multi-purpose cartridges (NIOSH or EN 14387 ABEK type).
For high-risk exposure: a full-face supplied-air respirator.
Regulation
United States
NIOSH: The National Institute for Occupational Safety and Health (NIOSH) recommends an exposure limit of 0.1 mg disulfoton/m³ of air for a 10-hour workday within a 40-hour workweek.
EPA: The Environmental Protection Agency recommends that no more than 10 parts of disulfoton per billion parts (ppb) of water be present in drinking water that children drink for periods of up to 10 days. Disulfoton in drinking water should not exceed 3 ppb for children or 9 ppb for adults if they drink the water for longer periods and should not exceed 0.3 ppb for adults who will drink the water during an average lifetime. EPA has designated disulfoton as a hazardous substance, but it does not intend to cancel or restrict registration of pesticide products containing disulfoton. Federal regulations limit the amount of disulfoton that factories can release into wastewater. The EPA requires industries to report releases or spills of 1 pound or more.
OSHA: The Occupational Safety & Health Administration has not established any regulation.
Australia
Safe Work Australia: Safe Work Australia has established a Time Weighted Average (TWA) concentration of 0.1 mg/m³ for disulfoton over a 40-hour workweek.
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