organofosfat

Organophosphates are a broad class of organophosphorus compounds that contain phosphorus bonded to oxygen and carbon in ester linkages. They typically feature a phosphorus(V) center with a P=O bond and multiple alkoxy or aryloxy substituents, resulting in a diverse family of phosphor ester compounds. The class encompasses a wide range of chemicals, including many used as pesticides as well as certain industrial additives and, in some cases, nerve agents.

Uses and notable examples vary widely. The most familiar applications are agricultural pesticides such as parathion, malathion, chlorpyrifos, and diazinon. Some organophosphates have been used as flame retardants, plasticizers, or hydraulic fluids. Due to toxicity concerns, many organophosphates have faced regulatory restrictions or phaseouts, particularly for residential and consumer use, and safety measures are emphasized in handling and application.

Mechanism of action and health effects. Organophosphates exert their toxic effects primarily by inhibiting the enzyme acetylcholinesterase, leading to the accumulation of acetylcholine at nerve synapses. This causes overstimulation of muscarinic and nicotinic receptors, producing a range of acute symptoms such as salivation, sweating, lacrimation, urination, defecation, diarrhea, vomiting, muscle twitching, seizures, and potentially life-threatening respiratory problems. Some compounds require metabolic activation to more potent oxon forms, which can influence toxicity. Chronic exposure and high-level exposure raise concerns for neurological and developmental outcomes.

Environmental fate and regulation. Organophosphates can undergo hydrolysis and degradation in soil and water, with persistence varying by compound and conditions. They can affect non-target organisms, including aquatic life. Regulatory frameworks in many countries restrict or ban certain organophosphates, promote safer handling practices, and mandate protective equipment for applicators.