Ingestion of Carcinogenic N-Nitrosamines by Infants and Children

Abstract

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 μg/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 μg/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 μg/kg body weight - d. Infants who use products like those tested may, therefore, be exposed daily to < 100 times more of these carcinogens than are adults. In countries where appropriate legislation has yet to be enacted or adequately enforced, these products may represent both a major source of exposure to potent carcinogens of children and, given the increased sensitivity of newborns to carcinogens, a most serious public health hazard.