|Jennifer Tully ('11) with the TEM at Miami University|
Jennifer (Miller) Tully graduated from Ashland in 2011 with a B.S. in Geology and a B.S.Ed. in Integrated Science Education. Her undergraduate research with Dr. Jeff Weidenhamer focused on the detection of toxic metals in consumer products. Jennifer wrote the following about her current experience in graduate school at Miami University.
My second to last semester is coming to a close, as I am getting closer to finishing up my Masters degree in geology. I spent this past summer collecting and analyzing river sediment samples for my thesis, which has involved examining heavy metal contamination in a stretch of the Great Miami River that flows through Hamilton, Ohio. After obtaining the bulk chemical data I identified samples of interest and further characterized those samples using scanning electron microscopy (SEM) to determine how heavy metals were manifesting themselves in the river sediment. I was able to identify coal spherules (from coal combustion) and particles of barium, lead and lead chromate (pigment in yellow road paint). The lead chromate was of particular interest because the Cr in this compound is Cr+6 (carcinogenic) and we found potential evidence for dissolution. I was then able to present my findings at the Annual Geological Society of America meeting held in Charlotte, NC and chair the session in which I presented.
There is still more work to be completed on this project as ICP-MS data indicated there are large amounts of Cu and Zn present in my samples; however I was unable to find any evidence via SEM. So, over winter break I will be working with the transmission electron microscope (TEM) and learning how to do scanning transmission electron microscopy (STEM), which is a technique, I will use to “map” elements on clay particles within my samples. This may help determine where Cu and Zn are in our samples and we will be able to determine if any other heavy metals are sorbing onto clay particles.
The first micrograph depicts lead chromate (bright white crystals) embedded in a Si/Ca/organics matrix (darker material), and the second micrograph is of a coal spherule.