Ingestion of carcinogenic N-nitrosamines by infants and children.

Volatile N-nitrosamines are very potent carcinogens. They can be approximately 5 million times more powerful than saccharin. One of two principal methods is generally used when assaying rubber products for nitrosamine content: (1) the German method (aqueous extraction) or (2) the U.S. method (dichloromethane extraction). When 16 types of baby-bottle nipples and children's pacifiers were tested recently, relatively high levels of nitramines, nitrosamines, and nitrosatable precursors were found. Eighty-one percent failed to meet the strict Dutch standards (based on the German method), but only 37.5% would have been banned according to U.S. regulations, which ignore nitrosatable-precursor content. Up to one-third of the nitrosamines present in a rubber nipple may migrate into the milk in the bottle within a few hours. Transfer into infant formula may exceed 40%, and transfer into saliva may be even higher. Thus, a highly contaminated nipple may cause a 5-kg infant who drinks 1 l/d to ingest approximately 2 micrograms/kg body weight.d of nitrosamines. To this, add any exposure resulting from pacifier use or from in vivo nitrosation of precursors. Therefore, daily exposure of infants may, in the worst case, conceivably reach 4-5 micrograms/kg body weight.d. Entire average daily exposure of an American adult to volatile nitrosamines from major sources is estimated to be less than 0.05 micrograms/kg body weight.d. Infants who use products like those tested may, therefore, be exposed daily to less than or equal to 100 times more of these carcinogens than are adults.(ABSTRACT TRUNCATED AT 250 WORDS)