organophosphaten

Organophosphates are a large class of organophosphorus compounds that are esters derived from phosphoric acid and related phosphorus acids. They typically feature a phosphorus atom double-bonded to oxygen (P=O) and bound to three substituents, at least one of which is an organic group; some derivatives have sulfur in place of oxygen (phosphorothioates), affecting reactivity and volatility. They are widely used as agricultural pesticides, agrochemicals, flame retardants, plasticizers, and, in some cases, as nerve agents.

Most organophosphates exert toxicity by inhibiting acetylcholinesterase (AChE), the enzyme that breaks down acetylcholine in nerve synapses. Phosphorylation of the active site leads to accumulation of acetylcholine, causing continuous stimulation of muscarinic and nicotinic receptors. In many organophosphates, aging of the enzyme-adduct increases stability and toxicity. Nerve agents such as sarin, soman, tabun, and VX are highly potent organophosphates; common pesticides include malathion, parathion, chlorpyrifos, and diazinon.

Uses and safety: As pesticides, organophosphates control insects in agriculture and stored products but pose significant risks to humans and wildlife. Exposure can occur via inhalation, skin contact, or ingestion and may cause symptoms ranging from headaches and dizziness to excessive salivation, bronchoconstriction, muscle weakness, and seizures. Acute treatment uses atropine to block muscarinic effects and oximes (pralidoxime) to reactivate AChE, along with supportive care.

Regulation and environmental concerns: Because of toxicity, organophosphates are subject to regulatory controls, restricted-use labels, and safety guidelines. Some are banned or phased out in many regions, with ongoing shifts toward safer alternatives and integrated pest management.