Seasonal Animal and Human Activity Near Recreational Water Sources in Pueblo, Colorado Is Correlated with Increased Total Coliform Levels

Abstract

Rapid population growth has increased the burden on recreational water sources, with elevated animal and human presence potentially impacting microbial water quality. Previous studies have suggested that high animal activity near water sources can contribute to microbiological contamination. Here, we evaluated whether increased animal and human activity levels correlate with total coliform and Escherichia coli contamination in recreational and control water sources in Pueblo, Colorado, USA. Activity scores were derived using a qualitative visual assessment of five environmental photographs per site at the time of collection. To incorporate seasonal variation, samples were collected across both Fall and Spring seasons. Water samples were analyzed using Most Probable Number (MPN) assays for E. coli and total coliforms, and further verified by growth on Eosin Methylene Blue (EMB) agar and Gram staining. Our findings reveal a strong correlation between total coliform contamination and activity scores during the Fall season. However, E. coli contamination showed more variation and was not significantly correlated with activity. These findings underscore the importance of continued seasonal monitoring and refined activity assessment tools to evaluate recreational water quality.