Graduate Student Asked to Return to NASA

William Clarke (M.S., Geology) spent 2008 at NASA as an intern where he determined the extent of bio leaching of grains of ilmenite (FeTiO4); cyanobacteria (as do most all bacteria) excrete organic acids. With these acids, minerals can be dissolved to release metallic elements into solution. The overall goal was to test how much of these metals are released over time, and find a viable way to extract the metals from solution before the bacteria utilize them for themselves. The study is being conducted for potential use on the moon as a bio-mining system, that would also produce oxygen (cyanobacteria turn CO2 into O2), to be used on a possible future lunar base or outpost.

Bill had to engineer how the flasks would be put together and sealed to remain as a closed system where he learned how to grow and harvest the bacteria for use in the experiments. He also worked on the Scanning Electron Microscope (SEM) looking at the surface of each grain used in the experiment. The SEM analysis resulted in visible bio-leaching signatures, such as small holes, crystal latius degradations, and bacterial shaped grooves etched in the surface.

When he returns summer 09, he will continue to work. The purpose of his returning is to more closely monitor the metal extraction, and devise a method for a continuous flow that would refresh the solution, and allow the bacteria to continue "mining" the metals (because the previous system would kill the bacteria once the solution was to saturated with elements, cause even essential metals can kill anything if there is too much of it). This is all with an end goal to produce publishable data.

 

NSF Predoctoral Fellowship Awarded to Israel del Toro

Israel del Toro, one of our graduates, has been awarded one of the prestigious NSF Predoctoral Fellowships to study the invasion ecology of ants at the University of Massachusetts, Amherst and the Harvard Forest LTER. He will begin his studies with Dr. Aaron Ellison in the fall.

 

Congratulations, Anita Thapalia

Anita was awarded a Geological Society of America Scholarship! The title of her proposal was: Development of Simple Leach Test for Construction Materials

 

Transport of Radionuclide Bearing Dust by Aeolian Processes, Peña Blanca, Chihuahua, Mexico: Preliminary Results

R. Velarde1, P. Goodell1, M. Ren1, T. Gill1,2

1 The University of Texas at El Paso, Department of Geological Sciences

2 The University of Texas at El Paso, Environmental Science and Engineering Program

This investigation evaluates potential radionuclide transport during wind erosion of high-grade uranium ore storage piles at Peña Blanca (50km north of Chihuahua City), Chihuahua, Mexico. Fractionation of soil, suspended dust, and radionuclides will be established. Grain size, mineralogy, and whether there is secular equilibrium will also be established. Three sediment collecting stations were deployed: S-1 upwind, S-2 on the repository, and S-3 downwind. One BSNE sediment catcher and marble dust trap per station were installed. Samples were collected by entraining the air with dust via a leaf blower (simulating a natural perturbation). Initially, element mapping and particle sizing were determined with an electron microprobe and Malvern 2000, respectively. Finally, gamma-ray spectrometry (i.e., Canberra HPGe) will determine radioactive levels and colloids will be analyzed for the presence of metals. At Station S-1 (72 meters west and upwind of repository), the predominant elements detected are Si, Al, K, Fe, and Ca. These elements are typically found in potassium-bearing silicate rocks such as potassium feldspars. The possible minerals are K-feldspars and calcite. For Station S-2 (at repository), the predominant elements detected are V, K, U, Si, Al, and Ca. Vanadium accompanies iron oxides, and argillaceous rocks; however, it is also found in industrial emissions (e.g., oil combustion residues). The uranium bearing mineral is uranophane. For Station S-3 (90.5 meters east and downwind of repository), the predominant elements detected are Zn, Ca, Si, and Pb. Zinc may have been deposited by hydrological processes or induced by collection mechanisms (i.e., rake, leaf blower, or sediment catchers). Trace lead may be attributed to vehicular emissions. The possible minerals are K-feldspars and calcite. Similar sites do not exist in the US (all uranium mining sites have been reclaimed). This study site can serve as an analog to active and inactive uranium mines worldwide. These studies have important implications regarding national security and public health.