A non-selective, non-residual contact dipyridilium herbicide which is highly toxic. Available commercially in the form of very soluble concentrates for dilution with water.
For etiology, clinical features, lesions, treatment and investigations, see Dipyridiliums


[toxic.gif] Toxicity
Oral doses in mg/kg or concentrations in mg/l:
LD50 rats 100-150
  mice 120
  guinea pigs 20-40
  rabbits 110
  dogs 25-50
  cats 35
 
monkeys  
 
50-70
 
cattle  
 
35-50
 
chickens  
 
110-360
 
turkeys  
 
290
  pheasants 28
  geese 120
  hares 35
LD
sheep  
 
8-10
  pigs 75
  ducks 100 for7 days
LC50 (96 h) fish 13-76



[case.gif] Case summary
A herd of ewes was put to pasture on a field which had just been treated with a paraquat based herbicide. Shortly afterwards, one animal presented with intermittent neurological signs: grinding of the teeth, paddling movements and opisthotonos. The ewe died several hours later. Of the remaining animals, only one case of mild diarrhoea was observed. Toxicological analysis of the ruminal contents showed a level of 2.7 ppm (2.7 mg/l) of paraquat; as the product readily degrades, the high level was adequate confirmation of the cause of poisoning.