Lead monitoring consumer information

Absorption, Distribution, Metabolism, Excretion. Examination of Section 2.6 clearly indicates that oral administration of NDMA has been the preferred route for studying its absorption, distribution, metabolism and excretion. This is not surprising since oral administration is easier to monitor when compared to other routes. The oral route seems to be the most pertinent to study since humans are most likely to be exposed to nitrosamines orally. Toxicokinetic data with regard to dermal and inhalation exposure of NDMA are clearly lacking. Furthermore, dermal and inhalation exposures may lead to different metabolic pathways and patterns of distribution and excretion, which could account for differences in the degree of toxicity exhibited by different routes of exposure. The metabolism of NDMA in isolated microsomal preparations seems to be well understood, but studies with cultured human cells could provide additional useful information. However, exploration of the denitrosation mechanism as an alternative to a-hydroxylation requires more attention. Determination of the urinary excretion of NDMA in control human volunteers and in individuals known to consume foods with high contents of nitrosamines could provide information concerning absorption and excretion of the xenobiotic. 

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