SYNTHESIS AND STABILITY OF DIMETHYLNITROSAMINE IN CATTLE MANURE

Beef cattle feedlots are a source of large quantities of organic and inorganic N compounds, among which are the precursors for the synthesis of N-nitrosamines, compounds carcinogenic to laboratory test animals and, possibly, to man. Objectives of this study were to determine if N-dimethylnitrosamine (DMNA) and N-diethylnitrosamine (DENA) could be detected in cattle feedlot manure packs; to identify and quantify nitrosamine precursors; to determine whether DMNA could be synthesized from dimethylamine (DMA) and nitrite (NO2-) added to manure and to determine the stability of DMNA in manures under aerobic and anaerobic conditions. Although the precursors necessary are present in manures, no DMNA of DENA was found at minimum detection limits of 0.02 ppm in manure. Aerobic incubation of manure with DMA-N (500 ppm) plus NO2--N (1000 ppm) generates detectable DMNA, but DMNA was not detected in samples incubated anaerobically or with lower levels of precursors. DMNA added to manure was relatively stable under aerobic and anaerobic conditions.