The students, led by junior applied geography (environmental analysis track) major and Grawemeyer Scholar Sam Kessler, invented the tool during a service project with Metropolitan Sewer District, Bernheim Forest and The Nature Conservancy. They volunteered to help monitor, clean up and restore streams in Louisville, including testing them for E.coli bacteria, which is found in biological waste and can sometimes cause disease. 

But, the team would have to consistently travel to each site — 10 sites across three different watersheds — at least five times per month to keep pace with the minimum testing required by the Environmental Protection Agency and Kentucky Department for Environmental Protection.

“With our class schedules, going to each of those sites multiple times per month wasn’t going to work for very long,” Kessler said. “We were traveling to some of these sites four times per week in between classes – Beargrass Creek, Bernheim Forest and all over. We needed something more efficient.”

To solve that problem, Kessler said, they invented a now patent-pending tool made from PVC pipe containing a special type of sediment material in mesh bags that can be left in the stream and read just once per month. Kessler believes their tool could dramatically improve the time and cost efficiency of testing.

“This is set-and-forget. You can leave it in the stream or river all month and test once instead of making at least five different trips,” he said. “And, because it’s in the stream all month instead of the isolated tests we currently do, you get more insightful results from a cumulative sample. This research could significantly improve the way we sample water for E.coli.”

Current testing only measures the levels of E.coli at the time of the test, not the days in between tests, Kessler said. For example, if a test on Monday shows no E.coli, the tester would have no way of knowing the stream was polluted the next day. Because the students’ tool can be left in the water all month, he said the result is a more comprehensive, cumulative sample.

“Understanding what makes safe, clean waterways is complex,” said Erin Wagoner, Environmental Partnerships Liaison for Louisville MSD. “From all the ways that land draining to a stream is used, to the chemical composition of the water in the stream, making these connections to improve the health of our waterways is a challenge. Creating a plan and developing a tool to make this process more efficient removes barriers to diagnosing the problems we are all trying to solve.”

While the tool has been tested only with E.coli so far, Kessler sees other potential applications. For example, he is interested in investigating whether it could be used to screen for SARS-CoV-2 by placing the device in wastewater.

“During COVID-19 specifically, limiting the amount of time human personnel are testing in the field is a smart thing to do,” Kessler said. “Maybe this could help.”

The Nature Conservancy is overseeing the planting of approximately 8,000 trees and shrubs in the designated neighborhoods. Researchers with the University of Louisville’s Christina Lee Brown Envirome Institute will compare data about the health of people living in the neighborhoods and air pollution levels collected before the plantings with data collected two years after the vegetation is planted. The results will provide insight into how the additional vegetation affects the health of people in the community.

“Our primary objective is to understand how increasing greenness affects the risk of heart disease within the community,” said Aruni Bhatnagar, PhD, director of the at the University of Louisville, who oversees the project. “Heart disease remains the leading cause of death throughout the world. We can treat heart disease with stents and statins, but we cannot prevent the disease. If we can show that putting in more trees will lower the incidence of the disease, even by a fraction of what it is, that would be a major achievement.”

The Nature Conservancy is planting the trees and shrubs in designated residents’ yards at no charge to property owners.

“We’re excited to enter the next phase of the Green Heart project,” said David Phemister, state director for in Kentucky. “Tree plantings at this scale require strong partnerships and deep engagement with the community. Green Heart is not just a science experiment – it is a deep investment to bring more nature to neighborhoods in the heart of Louisville.”

The residents’ health is being assessed by UofL researchers through the Health, Environment and Action in Louisville (HEAL) Study. The HEAL researchers obtained health information from approximately 700 participating residents of the Taylor-Berry, Jacobs, Hazelwood, Oakdale, Wilder Park and Beechmont neighborhoods before the planting began. They collected information such as blood pressure, cholesterol, heart health and other health indicators. The same participants will be evaluated again in two years to determine if these health indicators have changed.

“We wanted Louisville to become maybe one of the first cities in the country that makes its decisions through the lens of all forms of health,” said Christina Lee Brown, benefactor of the Envirome Institute. “That is the Envirome’s objective. This project is a magnificent example of healing our community from the roots up.”

In addition to the Envirome Institute and The Nature Conservancy, the project is funded by the National Institutes of Health and is supported by partnerships with Metro Louisville, Louisville Grows, Washington University in St. Louis, Hyphae Design Laboratory and the United States Forest Service. The total cost of the five-year project is more than $15 million.

A UofL video about this project is available on .