Human E. coli found in Burnet Woods Park after sewer overflow

By Bob Hyland, hylandrt@ucmail.uc.edu

An interdisciplinary team of undergraduates at the University of Cincinnati investigated human E. coli levels in soil after a combined sewer overflow (CSO)  event late Wednesday April 2 and early Thursday April 3.    

Data show a known combined sewer overflow in Burnet Woods Park may pose serious risk to the public health.  Samples taken at 8, 24, and 72 hours after the overflow contained alarming levels of human E. coli colony forming units (CFUs). One sample collected at the 8-hour interval contained E. coli at greater than 130,000 CFUs/100mL. For reference, the threshold for recreational waters is 200 CFUs/100mL.

Mounting evidence indicates combined sewer overflows (CSO) into the soils of Burnet Woods leave behind human E. coli bacteria at levels which can pose a public health risk. In spring 2025, students performed a temporal investigation of E. coli counts in the soil after a known CSO event. Results from this project agree with what’s found in the research literature, and show human E. coli at levels which underscore the years-long pleas from parks volunteers and advocates for the Cincinnati Parks Board of Commissioners to remediate the problem immediately.

A cursory review of the research literature helps contextualize and underscore the public’s concern surrounding CSO events in Burnet Woods. Soil retention of bacteria from resurfaced sanitary sewer water can be a concern with the presence of E. coli in heavily recreated spaces. CSOs have detrimental impacts on the quality of air, water, and soil.

An investigation compared antibiotic-resistant bacteria (ABR) E. coli presence in small-flow CSO discharges (like those in Burnet Woods) to wastewater treatment effluents and found CSOs contained significantly higher concentrations. 

This high-traffic urban park includes picnic shelters and other gathering spots, potentially increasing the likelihood of E. coli exposure when CSO events occur. Samples where taken at three locations.

The primary aim of this project is to educate decision makers without the requisite expertise so they can realize the need to (re)prioritize resource allocation in order to put public safety first. The project also aims to support the public’s right to know.