The chemical degradation of five N-
nitrosamides used widely for the experimental induction of
cancer has been studied with the goal of identifying, and experimentally validating, reliable methods that can be recommended for the destruction of carcinogenic N-nitrosoureas and related compounds in laboratory wastes. Although data are not yet complete, preliminary evidence indicates that none of the five methods studied thus far is ideal for hazard-control purposes. Decomposition with 1 mol/L
potassium hydroxide solution destroyed the N-
nitrosamides, but generated diazoalkanes, which are carcinogenic, toxic and potentially
explosive. Treatment with strong
acid in the presence of
sulfamic acid or
iron filings completely decomposed all N-
nitrosamides without forming diazoalkanes, but failed in the presence of
solvents which were immiscible with water. Cleavage with
hydrogen bromide in
glacial acetic acid proceeded to a point of maximum degradation, following which gradual reformation of the N-nitrosamide was observed; this resynthesis could be avoided by carefully bubbling
nitrogen through the reaction mixture, but degradation was slow or failed completely in the presence of hydroxylic
solvents.
Permanganate oxidation was effective in
sulfuric acid solution, but was incomplete when an alcohol or
dimethyl sulfoxide was present. Salmonella typhimurium tester strains TA1535, TA1530 and TA100, which detect base-pair substitutions in
DNA, detected mutagenic degradation products in each of the destruction methods, with the exception of the
hydrobromic acid/
acetic acid procedure.