FORMATION OF CARCINOGEN, N-NITROSOCARBARYL, BY INTERACTIONS OF CARBAMATE INSECTICIDE, CARBARYL AND SODIUM-NITRITE IN GASTRIC-JUICE OF RAT

The formation of the carcinogen N-nitrosocarbaryl from the insecticide carbaryl (N-methyllnaphthyl carbamate) in the presence of sodium nitrite has been studied in vitro in rat gastric juice at 37°C. N-Nitrosocarbaryl was formed very rapidly and a linear relationship between the time of incubation and the amount of N-nitrosocarbaryl formed was apparent up to 45 min (when the yield was about 0·45% of the theoretical). The yields of the N-nitroso derivative were significant even at low concentrations of carbaryl and sodium nitrite and the amounts formed were related to the quantity of the two precursors. The amount of N-nitrosocarbaryl in the gastric juice decreased rapidly after the maximum concentration had been reached. A number of different factors may interfere with the accurate estimation of the N-nitrosocarbaryl present. However, these results show that N-nitrosocarbaryl can be produced in rat gastric juice and this possible formation constitutes a potential carcinogenic risk. © 1979.