Experimental Study on Testing Soil with Water Arsenic Tests Modified by Temperature

1. Picture 2- Shen and Brumbaugh Working Picture 1- Brumbaugh Working Results The data came in the form of HACH test kit strips as shown in picture 4. The test shows that as heat is increased, so is the amount of arsenic detected. 90˚C drew out almost 150% of 80˚C which in turn was almost double of 70˚C. Surprisingly, 60˚C also drew out more arsenic than 70˚C. The temperature that detected the least amount of arsenic was room temperature. 50˚C detected the second smallest amount of arsenic. Experimental Study on Testing Soil with Water Arsenic Tests Modified by Temperature Introduction Arsenic is a non-water soluble element on the periodic table. Despite this, in many regions of the world, soil arsenic is suspected to be contributing to hazardous levels of arsenic in ground water. It is important to locate these regions, but most methods are costly and time-consuming. This experiment seeks to find an inexpensive, in-the-field means by which to test soil arsenic. This project is unique because the goal is not to mind a method to remove arsenic or find how arsenic effects anything. There are many remediation strategies, such as using ferns to draw out arsenic from water and soil, but there are not many ways to measure if the remediation strategies work. ICP tests use heat to digest arsenic out of samples. Also, for non-gaseous compounds, heat increases solubility. For those main reasons heat was chosen as the variable. For the experiment, water was heated prior to being mixed with soil. The soil and water mixture was tested as a water sample. Discussion The numbers that came back were much smaller than what was anticipated. All the test results were miniscule- the greatest numbers were around 1/3000 of the actual amount. Despite this, if more trials were done with the exact same procedure with different samples and they proved the equation to be correct, then this data could be used. However, this experiment was not a failure. More research is needed before a solution to the goal comes to a conclusion. Increased heat has shown to draw out an increased level of arsenic. Further modification could draw out an even higher level of arsenic. Future groups could modify the procedure and create an equation with a bigger percentage. This experiment also shows how it is easy for arsenic to travel from soil to water. This is a problem for many countries whose drinking water is affected by arsenic. If the experiment was to continue on, it would be better to work with bigger percentages. Heat has shown potential, but not all that potential was used. To fully utilize heat, the experiment must be conducted with a hot plate instead of a Bunsen burner. Then, the samples could be continuously mixed with the water at the desired temperature. The data would give a greater percentage. To test the percentage, test samples with varying levels of arsenic. Table 1- The amount of arsenic detected by number and percentage By Connie Shen and Andrew Brumbaugh Methods & Materials Heat. It is something that everyone understands and it is also something people do not even need to leave their houses to obtain. The method created was simple. Send 5 soil samples of a region known to contain arsenic –like Sweet Home- to the OSU Radiation Center. Then, heat distilled water to the temperatures tested, the first one being 50˚C. Once it reaches that temperature, dump the soil in and let the sample soak for 5 minutes. After the 5 minutes, a “water sample” is then created. This “water sample” is then run through the test like any other water sample. The temperatures tested were 50˚C , 60˚C, 70˚C, 80˚C, 90˚C and room temperature which was 19˚C. 100˚C was not tested because that temperature creates volatile gases. Graph 1- graph depicts % arsenic detected vs. temperature of water Picture 3- Bunsen burner heating distilled water Picture 4- HACH test kit strips, the form the data came in These strips were randomly chosen to represent their temperature Revised: February 15, 2007