CHRONIC TOXICITY TESTS OF SODIUM THIOCYANATE WITH SODIUM NITRITE IN F344 RATS

Sodium thiocyanate, a common environmental chemical, was found to increase the incidence of liver tumors in a group of rats treated with 0.08 % in drinking water. To test the possibility that thiocyanate was catalyzing the formation of carcinogenic nitrosa-mines from amines and nitrite in the food, a group of 20 male and 20 female rats was given a higher dose of sodium thiocyanate (0.32%) together with sodium nitrite (0.2%) in drinking water. Sim-ilar groups of rats were given 0.32 % sodium thiocyanate or 0.2% sodium nitrite in drinking water or were untreated. All treatments lasted most of the lifetime of the rats, at least 2 years. There was no difference between the groups, treated or untreated, in survival, or in the incidence of any tumor that could be related to the treat-ment. The results indicate that sodium thiocyanate is without car-cinogenic activity in rats, alone or combined with sodium nitrite. A common source of exposure of humans to carcinogens is to N-nitroso compound