Pesticidas

7 Cholinesterase inhibitor pesticides

Cholinesterase inhibitors are mostly used in agriculture for the control of softbodied insects. They consist of 2 distinct chemical groups of compounds: ophosphorus derivatives and carbamates (Figure 7.1). In both groups áre widely varying toxicities. The chemical difference is of interest, ~ntidotes useful in treating the organophosphorus type may notwork or
be contraindicated in poisoning by carbamate-type insecticides. Formuscontaining from less than 1 % to more than 95% of pure material are . only available. The highest concentrations are mostly used to prepare and wettable powders in factories, although TEPP and malathion con
J~ates have been available to the general publico
,'I'ábles 7.1 and 7.2 give fatal doses in experimentalanimals, and the data n:be used as an indication of hazard to humans. Thus, exposure to
.thylchlorothion, DEF, malathion, or Phostex is unlikely to cause fatal ,isoning, whereas EPN, parathion, Di-Syston, and Bidrin can be dangerous


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CHOLINESTERASE INHIBITOR PESTICIDES 125


Table 7.1 Organic phosphate pesticides
||Exposure Ilmit (mglm') |LD50 (mglkg) |
| Abate, temophos |10 |4204 |
|Acephate, Orthene | |361 |
|AnHofos| |360 |
|Azamethiphos | |1180 |
|Azinphos-ethyl, Gusathion-A | |12 |
| Azinphos-methyl, Guthion|0.2 |6 |
| Azodrin, monocrolophos |0.25 |18 |
|Bensulide, Betasan, Prefar | |271 |
| Bidrin, dicrotophos|0.25 |15 |
|Butamiphos | |845 |
|Cadusafos | |37 |
|Chlorethoxyfos, Fortress| |10 |
|Chlorfenvinphos, Birlane, Supona, Vinylphate | |24 |
|Chlormephos | |7 |
|Chlorpyrifos, lorsban| |135 |
|Chlorpyrifos-methyl | |1000 |
|Coumaphos Co-Ral | |15 |
|Cyanophos| |710 |
|Cythioate, Cyflee, Proban | |107 |
|DEF, S,S,S-tribulyl phosphorotrithioate | |250 |
|Diazinon...