A History of Groundwater Contamination and Treatment in Wooster, Ohio

May 1, 2020   /  

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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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)

30 thoughts on “A History of Groundwater Contamination and Treatment in Wooster, Ohio”

  1. Mason, nice water table map. I am a little unclear about the air strippers. Were they installed in 2005? Are there air strippers at both wellfields, or only the southern wellfield?

    1. Hello,

      The first air strippers were built in 2005 in the south wellfield, and additional ones were built in both wellfields on an as-needed basis.

  2. Hi Mason! Great water table map! It seems like a water table map would be useful for any community that taps the local aquifer for drinking water. What were some of the challenges to making this water table map? Do you think communities should invest in making water table maps?

    1. Hi Dr. Pollock!

      The main challenge for creating the water table map was finding the data necessary. The well logs provided by the ODNR were very convenient and almost always had all the data I needed, but some were very old or missing important pieces of data. The well logs also recorded depth to static water level, which is not helpful to compare to other parts of the aquifer because of changing topography. This was easy to normalize by subtracting the depth to static water level from the elevation.

      Part of my IS that I did not discuss here involved comparing Wooster to other towns that experienced similar contamination events. A town in Massachussettes also saw their drinking water source contaminated with TCE from a local manufacturing plant, but these manufacturing plants were in the shallower section of the aquifer, essentially the opposite of what we see in Wooster. As a result, this town saw much more adverse health effects, and the case gained national attention. If they had invested in a water table map, it is possible they would have known that contamination from the manufacturing plants was likely to spread to the rest of the aquifer, and they could have implemented preventative measures in advance.

  3. How do you think this study will influence what you do in the future?

    1. Hi!

      A big reason I chose this topic was because I wanted to be able to use my background in Earth Sciences to help people affected by environmental problems. This is definatly something that I would hope to continue to do in my future careers.

  4. This was really interesting to get some of the behind-the-scenes history of cleanup of the public water supply in the city. Thanks for putting together such an interesting project and poster.

  5. Thank you for you research Mason. Insistence and verification on the quality of our water is so important. Are the current checks and balances in place adequate? How can we keep our water safe on a larger scale?

    1. HI!

      Thanks for your question. Protecting drinking water quality is very important. From what I have seen in Wooster, the water treatment plant has done a great job of protecting and maintaining the quality of drinking water and has been very good about keeping the public updated on any changes. I would say the best way to keep water safe on a larger scale is to support candidates and legislation that will protect clean water sources in both local and national elections.

  6. Can you explain how an air stripper tower reduced contamination levels in the aquifer? I’m sorry, I’m a humanities major so I’m not familiar with many of these terms. Also, do you think other cities should take the steps Wooster did in order to reduce contamination in drinking water?

    Cool project, thanks for researching an area we are all familiar with!

    1. Hi Waverley,

      Air strippers are difficult for some STEM majors to understand, so no need to apologize! Basically, certain compounds like the ones I looked at have a high vapor pressure and low aqueous solubility, meaning they will dissolve in air better than they will in water. Air strippers take advantage of this by pumping contaminated water from the aquifer through a series of filters, while simultaneously pumping air through them. The contaminants dissolve in the air and leave through the top of the tower, while clean water is pumped back into the aquifer.

      Thanks for your question!

  7. Nice work looking into our historical water quality data! Do you think that appreciable vinyl chloride and DCE could be coming from sources other than TCE degradation?

    1. Hi!

      Thank you for your question. We were very fortunate with the circumstances surrounding the TCE contamination, as a general source and time range are known, which makes it easy to study. Currently, we know that there is contamination coming from other sources, but theories as to where it originated range from metalworking plants in town to old city dump no longer in use. I chose not to look into these sources for my IS because there is very little information on these sources, even with the water treatment plant. Still, it is very likely that DCE and Vinyl Chloride are originating from other sources.

  8. Great job Mason! This research is so important, and it’s clear how knowledgeable you are about the subject.

    1. Thanks so much, Ellie! I was just taking a look at your project and I thought you did a fantastic job as well!

  9. Thanks so much, Ellie! I was just taking a look at your project and I thought you did a fantastic job as well!

  10. Hi Mason,
    I found this information in your history: “Wooster, Ohio is a city whose groundwater has been affected by contamination as a result of the town’s industrial waste”

    Do the parties responsible for the groundwater contamination, industries, have to cover the remediation costs? Who pays to ensure citizens have safe water?

    1. Hi!

      The two main companies involved both claimed that they do not believe that they were responsible, but were willing to help the EPA with remediation efforts. This included drilling monitoring and interception wells on their sites, as well as monitoring contamination levels on site. In terms of cost, the cleanup efforts were funded by the taxpayers.

  11. How long does it take for TCE to leach into the aquifer? Is it quick transmission via percolation from the surface or is it deeper in the soil as a buried contaminant from decades of disposal?

    1. Hi!

      This is a great question, and one I am not entirely sure I know the answer to. The water treatment plant does not have any test results older than 1985, but the contamination from manufacturing plants began as early as the 1950s, so it’s hard to determine how quickly it became present at high levels. I would assume it was a quick transmission, but it is possible that it has been in the aquifer long enough to be buried deeper.

  12. Hi Mason–

    So proud of you for doing a virtual presentation at IS Symposium and reppin’ our department so well. Years ago, I took hydro from Dr. Bair, an amazing hydrogeologist at Ohio State. He was a graduate of Wooster and our department!! My first introduction to Wooster’s water problem with TCE, etc., was a field trip that I came on with him from Columbus to Wooster years ago. We visited the wellfields and saw the geography first hand. Life comes full circle.

    Again, great job finishing IS, doing this Symposium, and for finishing finals this week. -SJ

    1. Hi Dr. Judge,

      Thank you so much for your kind words, and for all you’ve done for me and the department these last couple years! In one of my earliest meetings with the water treatment plant, they told me this aquifer was one of the most studied aquifers in the country, so I am just glad I was able to do my part and push the research along. Hopefully, the next student will be able to expand on it even further.

  13. Nice job Mason – great points about just how heroic and busy the folks at the Wooster Water Plant have been over the years keeping our water safe. We are fortunate. Best wishes for your future in Environmental issues.

    1. Thanks Dr. Wiles! The Wooster Water Plant has been fantastic, both in helping with this study, and in protecting water sources. I never would have gotten in contact with them without your connections, so thank you for that as well!

  14. Hello Mason! Excellent poster. It’s so important to know what’s in our local water, and it’s great to see how well contamination has been handled at Wooster. I’m wondering if you know how long air strippers will have to be active to continue ensuring our safe drinking water. Great work!

    1. Hi Alexis!

      I actually don’t know the answer to that, and I could definitely see that being the topic of a future research project. I am fairly certain that as of right now, Wooster doesn’t have any plans of ending the use of air strippers, and they will likely be needed for quite some time, as contamination does continue to occur in the aquifer.

      Great job on your research with groundwater as well!

  15. Mason!

    This is so fascinating. As a history major and a relatively unobservant person, I found your presentation informative and engaging. I also thought it was cool that you chose Wooster for your study, which made me think a lot about all of the times I drank Wooster water over the last four years.

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