Soil Contamination in Rivers
Agricultural runoff from farm fields into a stream in Iowa.Copyright 2011 Lynn Betts, USDA Natural Resources Conservation Service, U.S. Department of Agriculture, Wikimedia Commons http://commons.wikimedia.org/wiki/File:NRCSIA99139_-_Iowa_(2979)(NRCS_Photo_Gallery).jpg
Students learn about contamination and pollution, specifically in reference to soil in and around rivers. To start, groups use color sensors to take light reflection measurements of different colors of sand (dyed with various amounts of a liquid food dye), generating a set of "soil" calibration data. Then, they use a stream table with a simulated a river that has a scattering of "contaminated wells" represented by locations of unknown amounts of dye. They make visual observations and use color sensors again to take reflection measurements and refer to their earlier calibration data to determine the level of "contamination" (color dye) in each well. Acting as engineers, they determine if their measured data is comparable to visual observations. The small-scale simulated flowing river shows how contamination can spread.
Civil, geotechnical and geo-environmental engineers investigate and mitigate soil and groundwater contamination in order to ensure safe health conditions for people who live nearby. Approximately half the U.S. population obtains its drinking water from groundwater so engineers make sure municipal water is safe to drink. Soil contamination is a topic on the forefront of many environmental conversations, and billions of dollars are required to clean up contaminated soil sites nationwide, such as the 1300+ "superfund" sites in the U.S. In this activity, use of an erosion table and the data collection, calibration, analysis and extrapolation engages students in typical engineering activities, helping them to see the connection between soil contamination and water pollution.
After this activity, students should be able to:
- Define pollution, its causes, and the different forms in which it exists.
- Describe the necessity for calibration in science experiments.
- Use a color sensor to make scientific observations.