Disulfoton

Disulfoton is an organophosphate compound that is used as a systemic insecticide and acaricide. It is a colorless oil, although commercial samples can appear as a dark brown liquid. Disulfoton is known for its high toxicity to mammals, including humans, and is classified as an extremely hazardous substance in the United States as defined in Section 302 of the U.S. Emergency Planning and Community Right-to-Know Act (42 U.S.C. 11002). Due to its high toxicity and the potential for causing widespread harm, its use is highly regulated or banned in many countries.

Chemical Properties

Disulfoton is chemically described as O,O-diethyl S-[2-(ethylthio)ethyl] phosphorodithioate. It has the chemical formula C_8H_19O_2PS_3. The compound works by inhibiting acetylcholinesterase, an enzyme essential for nerve function in insects, leading to their death. This mode of action is similar to other organophosphates.

Usage

Historically, disulfoton was used to control pests on a variety of crops, including cotton, tobacco, and ornamental plants. It was applied either directly to the soil or as a foliar spray. However, due to its high toxicity and potential for environmental contamination, its agricultural use has significantly declined.

Health Effects

Exposure to disulfoton can occur through inhalation, ingestion, or skin contact. Symptoms of poisoning can range from mild effects, such as headache and dizziness, to severe effects, including convulsions, respiratory failure, and death. The severity of symptoms depends on the amount of exposure. Immediate medical attention is required in the case of suspected disulfoton poisoning.

Environmental Impact

Disulfoton is highly toxic to aquatic organisms and can contaminate water bodies through runoff. It also poses a risk to birds and beneficial insects. Its persistence in the environment and potential for bioaccumulation are concerns for ecosystems and have led to increased regulation and monitoring of its use.

Regulation

In response to the risks associated with disulfoton, regulatory agencies in many countries have imposed restrictions or outright bans on its use. In the United States, the Environmental Protection Agency (EPA) has classified disulfoton as a Restricted Use Pesticide (RUP), meaning it can only be applied by certified applicators. The European Union has banned the use of disulfoton under its pesticide regulations.

Alternatives

With the phasing out of disulfoton, there has been a shift towards using less toxic and more environmentally friendly pest control methods. These include biological control agents, integrated pest management (IPM) practices, and the development of new, safer chemical pesticides.

See Also

• Organophosphate poisoning
• Pesticide regulation in the United States
• Integrated pest management