Dursban [3,5,6-Trichloro-2-pyridyl phosphorothioate] 
Dursban was stable when incubated with fresh rumen fluid or beef 
liver. When fed to cows, some unchanged dursban was found in feces but 
not in the urine or milk. Diethylthiophosphate and diethylphosphate 
were excreted in the urine (590). The oxon occurred in sprayed cattle (1704). 
After single doses of C1°-dursban were fed to rats, 90% of the 
radioactivity rapidly appeared in the urine and 10% in feces. Compounds 
IV and V were identified. However, only dursban itself seemed to accu- 
mulate in the tissues and this was essentially in the fat (1327). 
The metabolism of dursban in fish was studied in a tank containing 
soil and plants. After exposure to dursban, the fish were sacrificed 
and the fish and some water examined via paper chromatography. In 
addition to the oxygen analog (II) of dursban, the monoethyl analog (IIT) 
of dursban and its oxygen (IV) analog, 3,5,6-trichloro-2-pyridyl phosphate 
(V), and 3,5,6~trichloro-2-pyridinol (VI) were also found. In the fish 
tissues themselves, compounds II, IV, V, VI were found (1325). 
Cranberry beans were grown in a nutrient solution containing 50 ppm 
C136 Dursban. Some dursban was apparently lost as a result of the 
continuous aeration of the nutrient solution, Chromatography of plant 
extracts indicated the presence of seven metabolites, Of these, four 
were identified as: 3,5,6-trichloro-2-pyridyl phosphate; 3,5,6-trichloro-2- 
pyridinol; Ethyl 3,5,6-trichloro-2-pyridyl phosphate; O-ethyl-0-3,5,6- 
trichloro-2-pyridyl phosphorothioate (1328). 
c!4-and C136-labeled dursban was applied to cranberry bean and corn 
leaves. Within three days, about 80% of the radioactivity was lost, 
presumably by volatilization, The remainder was slowly metabolized. 
c1°6-chloride was found in the plants, indicating dehalogenation of the 
pyridinol had taken place. Analyses also showed the presence of 3,5,6- 
trichloro~2-pyridinol. The low level of radioactivity present in the 
plants made it impossible to obtain definite proof that compounds III and 
IV were present as plant metabolites or UV breakdown products (1326). 
Dursban was very stable under neutral or slightly acid conditions 
at room temperatures, Breakdown increased with pH. The half-life in 
water (pH not given) or soil was about 80-100 days. Exposure of 
crystalline dursban to UV converted it slowly from white to a brown color. 
In solution, decomposition was more rapid and complete. Chlorine was re- 
placed by hydroxyl groups which could undergo oxidation to keto groups. 
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