Environmental influences on fecal bacterial concentrations in Texas marinas

Tanu Uppal, The University of Texas School of Public Health


The presence of fecal pathogens in water systems poses a significant threat to human health and ecosystems. Often, it is difficult to ascertain the dominant source of fecal bacteria in recreational waters. Clear Lake, Texas, a tributary to Galveston Bay, is characterized by migrating and resident waterfowl, recreational boater activity, and the presence of bacterial hotspots, which cause it to be a potential contributor to fecal pollution in the Bay. Galveston Bay serves an important recreational and economic resource for Texas residents. In this study, we statistically analyzed water sample data collected during the summer of 2014 in order to determine whether there were any associations between wet weather events, weekend boater activity, and the presence of waterfowl and waterfowl guano and concentrations of fecal enterococci in two Texas marinas that reside on Clear Lake. Furthermore, we compared results with data from 2013 to determine if environmental influences were consistent year to year. Results showed significantly lower concentrations of fecal bacteria in the presence of guano on nearby piers at one of two marinas (chi-square p-value 0.0252). Effects of wet weather and weekend boater activity were insignificant at a marina where, in the past, these environmental parameters were significant contributors to fecal concentrations (wet weather, Pearson;s chi-square p-values 0.8999, 0.0475; weekend boater activity, McNemar's test p-values 0.060, 00473). Overall, results indicate that no single non-point source could be identified as the dominant contributor to fecal waste in these two marinas; combined effects of multiple sources may be responsible for presence of fecal bacteria in these waters.

Subject Area

Environmental Health|Environmental Studies|Water Resource Management

Recommended Citation

Uppal, Tanu, "Environmental influences on fecal bacterial concentrations in Texas marinas" (2015). Texas Medical Center Dissertations (via ProQuest). AAI1597552.