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N-nitrosodimethylamine (NDMA) is present in groundwater and drinking water from industrial, agricultural, water treatment, and military/aerospace sources. NDMA is a suspected human carcinogen and an emerging groundwater contaminant that has been detected at a number of Department of Defense (DoD) and National Aeronautics and Space Administration (NASA) sites involved in the production, testing, and/or disposal of liquid propellants containing unsymmetrical dimethylhydrazine (UDMH). NDMA was a common contaminant in UDMHcontaining fuels (e.g., Aerozine-50) and is also produced when these fuels enter the environment through natural oxidation processes. Currently, the most effective treatment technology for NDMA in groundwater is pump-and-treat with ultraviolet (UV) irradiation. However, this approach is expensive because it requires high energy input to effectively reduce the levels of NDMA to meet regulatory requirements. The objective of this Environmental Security Technology Certification Program (ESTCP) project was to demonstrate and validate the use of an advanced bioreactor design, a fluidized bed bioreactor (FBR), in the field for the ex situ treatment of NDMA from part-per-billion (micrograms per liter [ g/L]) influent concentrations to low part-per trillion (nanograms per liter [ng/L]) effluent concentrations. The demonstration was conducted at the NASA White Sands Test Facility (WSTF) in Las Cruces, NM. The capital and operational costs of the FBR were subsequently compared to those of an existing UV system for NDMA treatment at the WSTF facility.

A primary goal of this research program is to provide pertinent information about the energetics, photochemistry, and chemical dynamics of spacecraft effluents, including H2O, NH3, hydrazine (N2H4), monomethylhydrazine, and unsymmetrical dimethylhydrazine. By using the unique VUV laser facilities developed in our laboratory, we plan to perform high-resolution photodissociation, photoionization, and photoelectron studies of these molecules, and to examine their chemical interactions with major atmospheric ions, aiming to identify possible sources of optical emission signatures that can be used for reliable tracking and detection of spacecraft maneuvers and rocket launches.

The autoxidations of unsymmetrical dimethylhydrazine (UDMH) and a mixture of 50-percent UDMH and 50-percent hydrazine (50-50 blend) have been studied at pressures of several Torr in 44-cm reaction vessels and several ppm in a long path cell. With initial UDMH pressures of several Torr, autoxidation proceeded too slowly to be differentiated from natural decay processes. When the initial UDMH pressure was lowered to a few ppm, the addition of oxygen caused approximately first order decay with a half life of about 84 hours. The main oxidation product under these conditions was formaldehyde dimethylhydrazone. The 50-50 blend did not behave as two independent systems; instead, there were substantial positive synergistic effects observed. At concentrations of a few Torr of each component, the addition of oxygen resulted in a 10- to 20-fold increase in decay rate over that shown by UDMH or hydrazine by itself. At ppm concentration levels, the situation was similar for UDMH where a four-fold oxidation rate increase was observed when compared with a similar experiment with no hydrazine present. However, hydrazine oxidation in the 50-50 blend was somewhat slower that it was in a similar experiment with only hydrazine present. (Author)

The applicability of bacterial systems as an indicator of environmental toxicity was determined by observation of the effect of selected missile propellants on the growth dynamics of a soil microorganism. A soil isolate capable of rapid growth in a mineral salts medium was exposed to various concentrations of the propellants hydrazine (Hz), unsymmetrical dimethylhydrazine (UDMH) and monomethylhydrazine (MMH). Growth of the exposed cultures was followed turbidimetrically and compared to unexposed cells. Ten experiments were conducted indicating the order of toxicity to be Hz > MMH > UDMH. The bacterial response was a delay in the onset of log growth, with as little as 0.05 ppm Hz exerting on inhibitory effect. Responses were dose dependent and suggested a two-phased mechanism consisting probably of a bacteriocidal and a bacteriostatic component.

The reactions of chloramine with appropriate nitrogen bases to form unsymmetrical dimethylhydrazine or monomethylhydrazine were examined. Various by-products were identified and mechanisms proposed. Processes for the synthesis of both of these hydrazines were developed. The oxidation of unsymmetrical dimethylhydrazine by gaseous oxygen was studied and the various products identified. The oxidation of monomethylhydrazine was also investigated. The oxidation of unsymmetrical dimethylhydrazine by mercuric oxide was also studied. (Author)

The effects of exposure to pollutants on the development of Rana pipiens and Xenopus laevis embryos and larvae are described. Compounds evaluated include N-phenyl-alpha-naphthylamine, octyl-phenyl-alpha-naphthylamine, dioctyldiphenylamine, hydrazine sulfate, methylhydrazine, unsymmetrical dimethylhydrazine, and symmetrical dimethylhydrazine. Experiments focused on determination of lethal, teratogenic, and no effect levels of exposure. Techniques for exposing amphibian embryos and larvae to pollutants are also discussed.

This report describes recent work performed at The Aerospace Corporation to determine the capability of the CO2 laser photoacoustic technique to detect the rocket fuels hydrazine, monomethylhydrazine (MMH), and unsymmetrical dimethylhydrazine (UDMH) at low parts-per-billion (ppb) levels in the ambient air in real time. These compounds are highly toxic and recent studies indicate that they may also be carcinogens. Estimates made from CO2 laser absorption cross section data determined for the hydrazines in a previous Aerospace study indicate that the hydrazines should be detectable by the CO2 laser photoacoustic technique at the desired low ppb levels even in the presence of the ambient levels of pollutants and water vapor found in urban atmospheres. To assess the validity of these hydrazine-fuel detection estimates by the CO2 laser photoacoustic technique, various laboratory photoacoustic detection systems were assembled and their minimum detectable absorptivity values were determined during the present study. The photoacoustic detection system that provided the best performance in this study possessed optically tandem sample and reference cells connected to a differential capacitance manometer. This system was designed to minimize the effects of spurious absorption at the photoacoustic cell windows.

The fate of chemicals in aqueous environments is determined by diverse processes: chemical degradation, physical phase transfer, and dilution or dispersion. The study focused on the uncatalyzed aqueous decomposition (distilled, sea, and pond water) of hydrazine fuels. Despite their hypergolic nature, these fuels are remarkably stable in uncatalyzed aqueous solutions. Monomethylhydrazine (MMH) and unsymmetrical dimethylhydrazine (UDMH) were found to be extremely stable in distilled water, and had slow half-lives (10-14 days) in ponds and seawaters. As this study minimized biological decomposition and phase transfer losses, the aqueous half-lives of 10-14 days are very conservative figures and represent worst case situations. (Author)

Four animal species were exposed for 6-months to selected vapor concentrations of propellant grade unsymmetrical dimethylhydrazine to determine its oncogenic effects. The UDMH concentrations at or near the current threshold limit value were 0.05, 0.5, and 5 ppm. Animals were maintained for various time periods postexposure as long as: hamsters, 17 months; mice and rats, 19 months; and dogs, 54 months. The lung was a target organ in rats while the liver was the main target of 5 ppm UDMH induced neoplastic changes in rats and mice. Rats had an increased incidence of bronchiolar adenomas compared to controls. Mice exposed to 5 ppm UDMH developed a 4.7% incidence of liver hemangiosarcomas while controls had a 0.7% incidence. Kupffer cell sarcomas were also increased in UDHM exposed mice. Originator supplied

The subject of this report is the development of a portable system for the detection of low concentrations of nitrogen tetroxide (N2O4), fluorine (F2), and unsymmetrical dimethylhydrazine (UDMH) in air. The detection system is based upon the change of electrical resistivity of thin metal films when exposed to these gases. Silver metal films coated with appropriate salts proved to be applicable to the detection of all three gases; however, the following sensitized metal films were found to be optimum: for N2O4, silver; for F2, copper; and for UDMH, gold. Using the best film and salt combinations found to date, N2O4 could be monitored over the range of 0.1 to 50 ppm, F2 over the range 1.0 to 50 ppm, and UDMH over the range 10 to 100 ppm, with a standard deviation of about 20 percent. The effects of temperature over the range 50 to 90C and of humidity from 10 to 90 percent on the response characteristics of the thin film sensors were found to be significant but within the tolerance limits. Means for reducing these effects were suggested which, if successful, would, in effect, make this detection system practically independent of changes in the environment. A portable breadboard readout instrument was designed and fabricated for use with the sensors to form an integrated detection system for personal protection.

A research program was initiated to develop a personal colorimetric dosimeter for hydrazine fuels. An extensive literature survey was conducted to ascertain the most appropriate colorimetric reactions applicable to such a device. Many reagents were found which formed a color upon contact with various hydrazine vapors; however, most of these colored reaction products proved unstable during accelerated aging tests. Bindone, (delta 1,2' -- Biindan)--1', 3,3' -- Trione, uniformly dispersed on Eastman Chromagram Sheet (Type K301R2) was selected for incorporation as the sensing element in the dosimeter badge, because its response to hydrazine, unsymmetrical dimethylhydrazine (UDMH), and monomethylhydrazine (MMH) was both linear and readily observable. Synthetic color standards were developed and included in the dosimeter to provide the user with a means of estimating accumulated exposure within the range of 100-1800 ppm-minutes.

Solubilities of He, N2, and Ar in liquid hydrazine, methylhydrazine, and unsymmetrical dimethylhydrazine were measured at various pressures and temperatures. The results show that Henry's law is obeyed and the standard change of Gibbs energy is linear in temperature. The standard heat of solution and the entropy of solution were obtained, and the Gibbs energy was expressed as a linear function of temperature. The change in the solubility of a chosen gas from one solvent to another has been correlated by using the Lennard-Jones 6-12 potential with the assumption that the solute interacts with a hard core studded with H atoms. The functional forms of (Gibbs energy) = (heat of solution) - T(entropy of solution) for He, N2, and Ar in symmetrical dimethylhydrazine have been obtained from such correlations, and the method is shown to be useful for similar gas-liquid systems. It is shown that (a) the changes in the solubilities follow the changes in the dipole moments of liquids and (b) the entropy of solution varies linearly with the logarithm of mol fractions of solutes in methylhydrazine and in unsymmetrical dimethylhydrazine but not of solutes in hydrazine.