A study by researchers across multiple disciplines at the University of Kentucky has offered the most in-depth look at what’s flowing through Kentucky’s streams and rivers, and how these waterways can be safeguarded.

The work, published in Science of the Total Environment and led by Tiffany Messer, UK Martin-Gatton College of Agriculture, Food and Environment (CAFE) Gatton Foundation Endowed Chair, examined watersheds across the state — each representing a different land-use backdrop.

“About 95% of Kentucky’s drinking water comes from surface water, meaning that whatever ends up in our rivers and streams will eventually make its way into our water treatment systems,” said Messer, also an associate professor in the Department of Biosystems and Agricultural Engineering (BAE).

The team behind this study includes researchers from the Kentucky Water Research Institute, Martin-Gatton CAFE’s Department of Forestry and Natural Resources, and the U.S. Department of Agriculture’s (USDA) Agriculture Research Service at the University of Nebraska-Lincoln.

“Our goal was to understand exactly what contaminants are present and how different land uses influence water quality, so we can develop targeted strategies to protect both people and the environment,” said Messer.

This work is supported by the UK Center for Appalachian Research in Environmental Sciences (UK-CARES), Southeast Center for Agricultural Health and Injury Prevention housed in Martin-Gatton CAFE, U.S. National Science Foundation (NSF) and USDA.

A comprehensive sampling strategy

The researchers employed two complementary methods to capture a complete picture of contaminants over an extended period.

First, they collected traditional “grab” samples each month — a quick snapshot of the water’s condition at a specific moment. At the same time, they deployed Polar Organic Chemical Integrative Samplers (POCIS) — membrane-like devices left submerged for 30 days at a time. While grab samples can show the immediate levels of pollutants, these long-term samplers pick up traces of chemicals that might only be present sporadically, creating a more accurate account of average water quality conditions.

Over the course of eight months (March through October 2022), the researchers detected 77 contaminants. These ranged from conventional pollutants like fertilizers and trace metals to emerging contaminants such as personal care products and prescription drugs. By analyzing the data in concert with flow measurements from U.S. Geological Survey monitoring stations, the team could link changes in contaminant levels to rainfall, flooding events and seasonal factors.

One of the key takeaways was how strongly land use in different areas of Kentucky affected contamination “fingerprints.”

“We found that every region had its own unique set of contaminants. In urban areas, we detected more chemicals from lawn care, pet products and wastewater, including caffeine and certain pharmaceuticals,” Messer said. “Agricultural areas had higher levels of herbicides commonly used in farming, while the mining region showed elevated sulfate levels from mine drainage. Each landscape tells a different story about the sources of pollution.”

Beyond identifying these chemicals, the researchers examined whether levels ever topped standards set to protect fish and other aquatic life. In five cases, concentrations exceeded guidelines for freshwater organisms, meaning that these contaminants could potentially harm wildlife. Since most of Kentucky’s drinking water originates in surface waterways, these findings highlight the need for careful monitoring and management.

“During heavy rains, runoff from fields, roads and industrial sites rose significantly, flushing many of these pollutants into local streams in intense bursts,” Messer said. “These spikes were most pronounced in agricultural and urban areas, suggesting that improved runoff management could curb pollution peaks. Meanwhile, antibiotics and prescription drugs suggest that wastewater infrastructure may need upgrades in specific communities to filter out pharmaceuticals more effectively before water is discharged downstream.”

Searching for sustainable solutions

Identifying contaminants is only the first step. Messer’s team is already testing natural, low-cost treatments — particularly using constructed wetlands — to strip chemicals from the water before they become a threat to environmental or public health. Preliminary results, soon to be published in two additional papers, show that well-designed wetlands can effectively remove a broad spectrum of contaminants.

An integral part of this project has been a high school outreach initiative, called mesoWheels. According to Messer, this direct community engagement helps everyone see water quality as something they can actively protect.

“More than 1,000 students from 15 schools across Kentucky have taken on classroom experiments that mirror our team’s research,” said Messer. “These hands-on activities not only teach vital scientific principles but also invite young people to investigate their local streams, discuss environmental stewardship and propose their own ideas for solutions.”

With most of the state’s residents are dependent on surface water, the findings carry important implications. Understanding which contaminants are present — and how they get there — helps policymakers, water treatment facilities, farmers and everyday citizens decide where to focus clean-up efforts. From guiding regulations on fertilizer application to encouraging upgrades to wastewater systems, Messer said the research is a springboard for evidence-based decisions aimed at protecting both human and ecological health.

“The team’s forthcoming publications will explore in greater detail the specific designs and performance of these constructed wetlands, offering stakeholders practical solutions for pollutant removal,” Messer said. “For now, the takeaway is clear: While water contamination in Kentucky stems from many sources, there are tangible, cost-effective ways to reduce it, and local communities — engaged through classroom participation — are already helping pave the way toward cleaner, safer streams and rivers for all.”

BAE is a partnership between Martin-Gatton CAFE and the Stanley and Karen Pigman College of Engineering. To learn more, visit https://www.engr.uky.edu/research-faculty/departments/biosystems-agricultural-engineering.

Research reported in this publication was supported by the National Institute of Environmental Health Sciences of the National Institutes of Health under Award Number P30ES026529 and the National Institute for Occupational Safety and Health of the National Institutes of Health under Award Number 5U54OH007547. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Research reported in this publication was supported by the U.S. National Science Foundation under Award No. 2042761. The opinions, findings, and conclusions or recommendations expressed are those of the author(s) and do not necessarily reflect the views of the U.S. National Science Foundation.

This material is based upon work that is supported by the National Institute of Food and Agriculture, U.S. Department of Agriculture, Hatch Project under award number W-4045. Any opinions, findings, conclusions or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the Department of Agriculture.

University of Kentucky alum and former trustee Carol Martin “Bill” Gatton bestowed a transformational $100 million gift to the UK College of Agriculture, Food and Environment through The Bill Gatton Foundation. It is the largest gift to the university in its history. Four Pillars of The Bill Gatton Foundation's Gift are Scholarships and Student Success Initiatives; Companion Animal Program; Capital Projects and New Initiatives Fund; and Faculty Research.