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Key value for chemical safety assessment

Additional information

Genotoxicity in vitro

No evidence of mutagenicity was seen in a guideline-comparable Ames test performed with anhydrous ammonia (Shimizu et al, 1985) or in a guideline-compliant Ames test with the read-across substance ammonium sulphate (BASF, 1989). Similarly, there was no evidence of mutagenicity in a non-standard study using E. coli (Szybalski, 1958).

Genotoxicity in vivo

No evidence of an increase in the incidence of micronucleated polychromatic erythrocytes was seen in a mouse micronucleus assay performed with the read-across compound ammonium chloride (Hayashi et al, 1988).

Ammonia is a simple molecule and does not possess any structural alerts for genotoxicity. Ammonia is present at relatively low levels in the systemic circulation as a consequence of protein catabolism (largely in the liver) and is also present at higher levels in the hepatic portal circulation due to the breakdown of urea by gastrointestinal bacteria. The ubiquitous presence of ammonia in the leads to the conclusion that it is unlikely to be genotoxic. The WHO evaluation (EHC 54, 1986) concludes that there is no evidence that ammonia is mutagenic in mammals. A UK Health Protection Agency (HPA) evaluation similarly concludes that ammonia does not have significant mutagenic potential.

Short description of key information:
Anhydrous ammonia is not considered to be genotoxic based on the results of studies in vitro and in vivo with the substances aqueous ammonia, ammonium chloride and ammonium sulphate.

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

No classification is proposed for anhydrous ammonia: there is no evidence for genotoxicity in studies performed in vitro or in vivo.