Increasing Occurrence of High Fecal Indicator Bacteria (FIB) in Headwater Streams Within the Lower Delaware River Watershed

Elaine Langone Center, Forum

According to United States’ Environmental Protection Agency (EPA), bacteria and pathogen contamination has been ranked as the leading cause for impaired and threatened waters nationwide including streams in the Delaware River Watershed. Historic bacteria samples from the lower Delaware River Basin have primarily been collected from larger streams at the base of contributing sub-watersheds. As a result, there is little information on the status of bacterial contamination in headwater streams in this region. Headwaters constitute more than three quarters of the stream length in these watersheds and significantly influence water quantity and quality (physical, chemical and biological). In this study, we monitored fecal indicator bacteria (FIB) including total coliform, E. coli and Enterococci at 46 upstream sites across Delaware River Watershed, including the White Clay Creek, Red Clay Creek, Brandywine Creek, and the Schuylkill River. These data indicated an increasing occurrence of high FIB in the watershed. The concentrations of total coliform, E. coli and Enterococci were significantly higher than the EPA standards, suggesting a rising public health threat, a potential risk for surface-fed drinking water suppliers, and a challenge for watershed managers. Relationships between concentrations of FIB and landuses and other stream and watershed physical factors (e.g., watershed size, population density, location of known point sources) are also explored and discussed. Finally, molecular source tracking methods were used to identify the possible sources for FIB contamination, and our results indicated that headwaters are more susceptible to local landuses, and the bacterial contaminations are likely related to agriculture, urbanization, mushroom operations, and wildlife.