Indicator Bacteria in Beach Environments

Abstract

Bacterial presence in the environment has become a growing concern in recent years. The exposure of the public to elevated levels of microbes in the environment has been linked with respiratory and gastrointestinal illnesses. It is important to understand the behavior of bacteria in the environment in order to address public health concerns. This project was intended to improve our understanding of bacteria in the environment that are used as indicators for fecal pollution. Using the standard indicator species E. coli and Enterococci data was collected at Bradford Beach in Milwaukee Wisconsin throughout the summer months of 2013 and 2014. In order to better understand enumeration of these species from sand samples an experiment was conducted comparing the effectiveness of PBS and DI water as eluents. This experiment found that on average DI water served as a more effective eluent for E. coli while PBS was somewhat better for eluting Enterococci. Another investigation included the impact of algae on bacteria levels. It was found that indicator bacteria are elevated in water and sand directly adjacent to algal mats but no significant differences were found at larger distances. Other factors investigated were the effects of rain, temperature, and time on indicator bacteria levels in water. Moderate positive correlations were found for rain and temperature while no significant temporal correlations were found.