Bacterial toxicity and metabolism of three hydrazine fuels

Abstract: Hydrazine based fuels are used for Titan and Minuteman missiles and the F-16 aircraft and by the Space Shuttle Program. These uses represent significant production, transportation, and storage of these fuels, and, as such, a serious threat to the aquatic environment from the potential for accidental release. This research sought to determine the toxicity of hydrazine (H), monomethyl hydrazine (MMH), and unsymmetrical dimethyl hydrazine (UDMH) to four enriched bacterial cultures: Nitrobacter, Nitrosomonas - Nitrobacter, anaerobic bacteria, and denitrifying bacteria. In addition, the metabolism of hydrazine by Nitrosomonas - Nitrobacter was examined. The toxicity studies used batch bioassay methods with response measured in terms of substrate metabolism rates. Results showed that hydrazine produced a 50% reduction in metabolism rate for Nitrobacter, Nitrosomonas - Nitrobacker, anaerobic bacteria and denitrifying bacteria at concentrations of about 15, 165, 100 and 100 milligram per liter, respectively; monomethyl hydrazine at 15, 1, 75 and 10 milligram per liter, respectively, and UDMH at 1800, 35, 2300, and 12,500 milligram per liter, respectively. It was concluded that spills of these three fuels could be expected to seriously disrupt the natural bacterial balance in the aquatic environment. In addition, use of biological waste treatment for detoxification of these three fuels is not recommended.