Ray's Blog

First Blog

Normally I would be under the supervision of Sam Ying, but right now she is in China collecting samples so for the past few weeks I have been interning for Kristin Boye. In the the past couple days, I've learned a lot of new skills and was taught how to use many different machines, I also use some old machines that I used last year that was a fun reminder of all that I learned last year. Last year I grinded and prepped a lot of samples of the x-ray fluorescence machine, so in the beginning I started by doing what I already knew. For the first few days I grinded a lot of soil and prepared a lot of samples to run through the XRF machine, but after a few days I started to learn and do different activities. Grinding soil is pretty simple because all you use are mortars and pestles, but recently I learned how to use the plant grinder machine to grind plants. Plant grinding is a lot less tiring because you don’t have to use strength, all you have to do is operate a machine. Also most recently I used syringes and water to measure the volumes of vials so that my mentor could calculate the concentration of the gas that was in the vials before. Soon Sam Ying will come back and I will probably start to grind the soil she brings back from China.

Second Blog

Right now I am under the supervision of Sam Ying, she recently came back from China. In China, she collected over 140 samples of soil; there are 70+ surface soils and 70+ soils from 10 cm under the surface. There soils are similar to the ones she brought back 2 years ago, but the main difference between them is that she collected soil samples from a much larger radius than she did last time. The sites where she collected the samples are farther from each other when compared to 2 years ago. Also this time she didn't collect soil from all surfaces, she focused on crop fields and some lotus ponds and ignored surfaces like cement and dirt near roads.

She wanted to XRF all of the samples she had, and so the soil she brought back need to be ground; we started immediately after she got back. The most difficult part of the process was the drying of the samples; all the samples were extremely wet, especially the ones that were from below the surface. We decided to put the soil into cups so it could air quicker; a week later we started to grind the soil. It took a long time, but just a while ago we ground all 140 samples and we have almost put all of them into the XRF. With the XRF we can see what elements the soil is composed of; the XRF sends x-rays through the soil and lists the percent of each element that is in the soil starting with calcium. The XRF is unable to detect lighter elements like carbon, so for the coal, fly ash , and some soil samples she brought back we used a carbon elemental analyzer to see how much carbon the samples had. For the elemental analyzer we weighed out the samples into foil balls and combusted to measure the gas. Soon we will have all the data and she will walk me through what it means and how to analyze it.

Third Blog

For the past summer, We have ground a lot of soil so that it could be prepped and ran through the X-ray fluorescence. Just two weeks ago, we completed running all the samples through the XRF. Now we can look at the data from 140 samples, we would compare the surface samples to the deep samples to see if the surface is enriched. The focus of my summer was to how much the soil was enriched by trace metals, we focus on lead, chromium, arsenic, manganese, zinc, and cadmium. To calculate the enrichment factor, I had to use this formula ([Pb]surface/[Ti]surface)/ ([Pb]deep/[Ti]deep). The reason we compare it to titanium is because the amount of titanium in the surface and deep are close and doesn't change. Then after you plug it in, you receive a number if that number is greater than 1 it means the soil is enriched by the element you used as your numerator. If the number you get is below one it means that the soil is depleted and there is more of the element in the deep than there is in the surface. Right now when we compare surface soil and deep soil it is called local enrichment, but in the future when we receive the XRF data of the deep cores we will be able to calculate regional enrichment which is replacing the deep data in the enrichment factor formula with the deep core data. So hopefully before AGU we will be able to have all the deep core data.

To read more about Ray's adventures in 2013, see https://sites.google.com/site/earthscienceshighschool/2013-general-program-intern-blogs/ray-s-blog