Organochlorine (OC)
Definition
Chlorinated hydrocarbon insecticides (DDT, BHC/lindane, endosulfan, dicofol, aldrin, dieldrin). Highly lipophilic, neurotoxic via voltage-gated sodium channel disruption, and persistent in fat and breast milk. Most are banned or restricted under the Stockholm Convention.
- Examples
- DDT, BHC/lindane, endosulfan, dicofol, aldrin, dieldrin
- Mechanism
- Voltage-gated sodium channel disruption
- Persistence
- Highly lipophilic, accumulates in fat and breast milk
- Regulatory status
- Mostly banned or restricted under the Stockholm Convention
Common questions
Why does organochlorine persistence matter for forensic wildlife or human poisoning cases?+
Because these compounds accumulate in fatty tissue rather than being rapidly excreted, they can be detected in fat, liver or milk samples long after exposure, which lets toxicologists identify chronic or historical exposure even when the acute poisoning episode occurred weeks or months before sampling.
How does an organochlorine's mechanism of toxicity differ from an organophosphate's?+
Organochlorines disrupt sodium channel gating in nerve membranes, causing prolonged depolarisation, while organophosphates work by irreversibly inhibiting the acetylcholinesterase enzyme, causing a buildup of acetylcholine at synapses. The two toxidromes differ clinically, which helps a toxicologist narrow the likely poison class before confirmatory testing.
Related terms
- AChE / BChE
- Acetylcholinesterase (RBC membrane bound, true cholinesterase) and butyrylcholinesterase (plasma, pseudo-cholinesterase). Both depressed in OP and carbamate exposure; plasma BChE falls first and...
- Aluminium Phosphide (AlP)
- Solid grain-fumigant rodenticide sold as Celphos, Quickphos, Sulfas tablets. On contact with moisture or stomach acid, releases phosphine (PH3) gas, which blocks...
- Carbamate
- Carbamic-acid ester insecticides (carbaryl, carbofuran, propoxur, aldicarb). Reversibly inhibit acetylcholinesterase by carbamylating the active-site serine; spontaneous decarbamylation makes oximes unnecessary and sometimes...
- Ellman Method
- Standard spectrophotometric cholinesterase assay. Acetylthiocholine substrate plus 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB) yields a yellow 5-thio-2-nitrobenzoate anion read at 412 nm. The rate of...
- Organophosphate (OP)
- A class of insecticides (monocrotophos, chlorpyrifos, methyl parathion, dichlorvos, phorate) that inhibit acetylcholinesterase, producing the cholinergic toxidrome. The dominant suicidal poison in...
- Pyrethroid
- Synthetic analogues of natural pyrethrins (deltamethrin, cypermethrin, permethrin, fenvalerate). Act on voltage-gated sodium channels like OC but break down quickly in mammals,...
- QuEChERS
- Quick, Easy, Cheap, Effective, Rugged and Safe sample-prep protocol for pesticide residues. Acetonitrile extraction, MgSO4 + NaCl partition, dispersive SPE clean-up with...