Diguat [1,1'-Ethylene-2,2'-dipyridinium dibromide] 
Paraquat. [1,1'-Dimethy1-4,4'-dipyridinium di(methyl sulfate) ] 
ce *ipiguat and paraquat, administered as a single oral dose to rats, 
appeared in feces within 2 days. The percentage of the dose appearing in 
the urine seemed to depend on the strain of rat used. After an oral dose, 
the bulk of the material appeared in the feces; whereas after a subcutaneous 
dose, most of the diquat and paraquat was in the urine. There was no marked 
biliary excretion. Comparison of colorimetric and radioactivity determina- 
tions on feces indicated that about 70% of the oral dose of diquat and about 
30% of an oral dose of paraquat appeared in feces in a degraded form. 
Incubation with a fecal homogenate, heat treated and not heat treated, 
demonstrated that the degradation was the result of microbiological action 
(336). 
After administration of labeled diquat and paraquat to dairy cattle, 
only about 0.001 - 0.015% of the ingested dose appeared in the milk. 
Analyses indicated several metabolites arose from diquat. Very little 
(less than 3%) of either compound appeared in the urine. Most of the 
diquat ingested was excreted on the second day after dosage; and, after 
eleven days, no measurable radioactivity was present. Tissue levels were 
very low except in organs of excretion (1361). 
After feeding dairy cattle and sheep on diquat-—treated silage, no 
residues were detected in the milk of the cattle nor in the meat or organs 
of the sacrificed animal. Incubation of diquat with sheep feces or rumen 
liquor resulted in an appreciable loss of diquat (119). 
Studies with labeled material indicated that those compounds were not 
degraded by alligatorweed. Both compounds reacted as free radicals (510, 
686). 
Paraquat dihydrochloride was applied to maize, tomato, and broad bean 
plants as droplets of an aqueous solution. There was little or no loss of 
paraquat on plants kept in darkness. When treated plants were exposed to 
sunlight, 4-carboxy-l-methylpyridinium chloride and methylamine were 
detected (1319). 
Isolation of micro-organisms were made from a wide variety of soils, 
some of which had been treated with paraquat prior to sampling. 
Corynebacterium fascians (Tilford) Dowson, Clostridium pasteurianum 
Winogradsky and some unidentified anerobes, and Lipomyces starkeyi, 
a yeast, were able to degrade paraquat (76). Reduction of paraquat and 
diquat to colored free radicals was observed in fungal and bacterial 
cultures. In some cases, the organisms were colored, indicating entrance 
178 

