Tracking toxins: A pilot investigation of cyanotoxins in north-central Tennessee’s surface waters and wells

Toxins
By: , and 

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Abstract

Cyanobacterial toxins (cyanotoxins) threaten aquatic ecosystems and human health, yet the factors influencing their production and distribution in freshwater remain unclear. In north-central Tennessee, nutrient-rich runoff from agricultural and urban areas, combined with a karst landscape that supports drinking and recreational water use, heightens the need to understand cyanotoxin behavior. To examine cyanotoxin patterns, the U.S. Geological Survey and the Tennessee Department of Environment and Conservation monitored 18 sites, including two wells under the influence of surface water, every two weeks from September 2022 to November 2024. At least one cyanotoxin was detected at all sites, with the highest concentrations in deep reservoirs and lower levels in shallow systems. Most detections occurred during summer and fall, aligning with high temperatures and rapid-onset drought. Statistical analysis indicated that increased specific conductivity and pH raised the likelihood of detecting total microcystin, likely resulting from drought conditions and nutrient-laden runoff. Additionally, dissolved microcystin showed an inverse relationship with Cumberland River water levels, and principal component analysis showed that Secchi depth, chlorophyll a, pH, temperature, and conductivity explained most water quality variability. These results help increase understanding of cyanotoxin distribution and associated water quality conditions during detections to guide future freshwater cyanotoxin monitoring studies.

Suggested Citation

Hill, K., Jaegge, A., Moore, D.M., and Byl, T.D., 2026, Tracking toxins: A pilot investigation of cyanotoxins in north-central Tennessee’s surface waters and wells: Toxins, v. 18, no. 6, 239, 27 p., https://doi.org/10.3390/toxins18060239.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Tracking toxins: A pilot investigation of cyanotoxins in north-central Tennessee’s surface waters and wells
Series title Toxins
DOI 10.3390/toxins18060239
Volume 18
Issue 6
Publication Date May 22, 2026
Year Published 2026
Language English
Publisher MDPI
Contributing office(s) Lower Mississippi-Gulf Water Science Center
Description 239, 27 p.
Country United States
State Tennessee
Additional publication details