Hello, Internet! I’m Maya Domeshek (’18) and I’m working on the Paradise Pond Sediment Sluicing Project. I’ve been working on it since last fall, and it’s been one of the great pleasures of my first year at Smith that I’ve been able to spend time on the pond in all seasons and weathers. I especially enjoyed collecting sediment samples this fall (who doesn’t like to get their hands covered in mud?) and traversing the pond and the Mill River in a row boat, a pontoon boat, and a canoe. As the River Rat in The Wind in the Willows would say “There is nothing—absolute nothing—half so much worth doing as simply messing about in boats. Simply messing.”
But Geology isn’t all field trips; it’s also lab work and data analysis. So I thought I’d take this opportunity to tell you a little about what we do in the lab and the wonderful laboratory machines that Marc Anderson tends and explains with such love. Much of my research work this past year has been focused on analyzing the sediment samples we’ve collected in order to to determine their metal content. We would like to know, for example, if they have high lead concentrations so that we don’t wash anything poisonous downstream. Don’t worry—so far none of our sediment has dangerous levels of lead.
When I analyze a sediment sample for metal, I take a few grams of sediment and heat them with nitric and hydrochloric acid and then burn off the organics with peroxide. This pulls most of the metal into solution. I then dilute the acidic water and soil solution to a known volume and measure the concentration of metal in that solution. Once I know the concentration of metal in a known volume, I can calculate the total amount of metal in that known volume and thus the total amount in the few grams of sediment I started with.
My favorite part of this process is that I get to measure the concentration of metals in the sediment using the lab’s ICP-OES (Inductively Coupled Plasma Optical Emission Spectrometer). This machine takes a small amount of a sample and heats it up hotter than the surface of the sun. It then measures the intensity of light the atoms in the sample emit at their characteristic wavelengths. Based on these intensity measurements, it can calculate the concentration.
There are many other things do in the lb and many other fascinating instruments to do them with. My fellow student researcher Lizzie often works with the Hydra C, which measures mercury using atomic absorption (not emission). Lyn has been looking at the changing chemistry of the water over the course of a storm, so she often uses the IC which measures the concentration of ions like nitrate and sulfate. And Marcia has been determining the size makeup of the sediment, which actually only requires sieving.
I suppose that’s enough information about lab procedures and machines for now. But, it really is amazing to think about how much thought and work that went into creating the analytic tools we get to use. Check back next time to hear about data analysis.
-Maya Domeshek ’18 is currently working on the Paradise Pond Project as a CEEDS-supported Summer Undergraduate Research Fellow with Professor Robert Newton. She has not yet settled on a major, but in her free time she enjoys dancing, dance teaching, and sharing a meal with friends and family.