A History of Groundwater Contamination and Treatment in Wooster, Ohio

Student: Mason Minerva
Major: Geology
Advisors: Dr. Alex Crawford, Dr. Greg Wiles
Contamination of drinking water can be incredibly problematic for the associated community, causing health problems that can be harmful for generations. There have been safeguards established in order to protect drinking water, including laws, and infrastructure built into community water treatment systems in many communities in the US. The success of these efforts vary among the locations, and understanding the causes and successful remediation efforts are important for creating future plans to deal with other water contamination events. Wooster, Ohio is a city whose groundwater has been affected by contamination as a result of the town’s industrial waste. By using GIS techniques and running statistical tests on volatile organic compounds and well log data, this study aims to provide a history of contamination and remediation of Wooster’s drinking water by showing visual and statistical representations of the data. Overall, the contamination within the aquifer has decreased greatly since it’s detection.

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Description

Previously, the EPA has ordered site clean ups in Wooster due to Trichloroethylene (TCE) contamination in drinking water. When consumed, TCE is known to cause a number of health problems, including cancer, liver problems, and death when consumed in high amounts. If not removed quickly, then TCE can degrade into dichloroethene (DCE), which further degrade into Vinyl Chloride, both of which lead to similar health problems. The City of Wooster has made significant efforts to decrease contamination levels and prevent further contamination. This study aims to evaluate these efforts and examine how the aquifer affected contamination rates.
One goal of this study was to map the water table in order to determine how groundwater will flow within the aquifer. In order to do this, location, elevation, and depth to static water were recorded from well logs provided by the Ohio Department of Natural Resources. Using the GIS tools available, we were able to create a map that showed the water table was shallowest in the northeast part of the aquifer, and got deeper as it moved towards the buried valley in the southwest part of the aquifer, where the wellfields are located. Groundwater will flow downgradient from the shallowest depths to the deepest, bringing any contamination with it. Therefore, deeper parts of the aquifer, like the well fields, are at risk of contamination that occurs anywhere else in the aquifer, however contamination that occurs here is unlikely to spread to other locations.
There was not enough for TCE to plot on a graph, so DCE and Vinyl Chloride results at the S-1 well and the air stripper towers were examined to determine change over time. In this data, the DCE levels decrease soon after testing begins, and remains below EPA maximum contamination level (MCL) for a majority of the time. It did begin to increase again after 2005, never back to previous levels. The air strippers were implemented to remove contamination from the aquifer. Here, levels are brought down quickly and remain low for most of the time series, indicating their success. There are some spikes in contamination, most likely due to mechanical
error. Vinyl Chloride is not present at the S-1 Well until 2005. After then, it is detected often, but not enough to cause significant concern. In the Air Strippers, VInyl Chloride is almost never found, meaning they are successful in removing it from the aquifer.
Mason will be online to field comments on May 8:
2-4pm EDT (PST 11am-1pm, Africa/Europe: evening)

Posted in I.S. Symposium, Independent Study on May 1, 2020.