DETECTION AND SOURCE TRACKING OF FECAL POLLUTION IN ALABAMA RIVERS

Alabama has an amazing network of streams and rivers that provide opportunities for recreational activities, including swimming, boating, and fishing, as well drinking water to more than one-fourth of the state’s population. However, these aquatic environments also receive fecal pollution from unprocessed human wastewater (e.g., failing septic systems or sewage overflows following large storms), manure from concentrated animal farming operations (both cattle and chickens), and wild animals (birds, fish, deer, feral hogs, etc.). To better understand the extent and sources of fecal pollution, river water samples were collected monthly for two years at fifteen locations (ten constant and five variable) on each of three rivers by their associated Riverkeeper organizations. After DNA was extracted from replicate subsample filters, droplet digital PCR (ddPCR) was performed to determine the presence and origin of Bacteroides, a gut-obligate, anaerobic bacterial genus. By obtaining variable location samples upstream of fecally-impacted constant sampling sites and employing a multiplex ddPCR assay to identify various sources of Bacteroides, specific point and non-point sources of fecal pollution have been identified. Not surprisingly, precipitation appears to impact the movement of fecal material into rivers, both via enhanced overland flow and by creating episodic sewage overflow events. Quantitative microbial risk assessments are underway to better determine the human health risks associated with exposure to fecally-polluted river waters, particularly from human sources.

Presentation Preference: Oral

Primary Presenter: Julie Olson, University of Alabama (jolson@ua.edu)

Authors:

Julie Olson, University of Alabama  (jolson@ua.edu)

Kellan Hoffman, University of Alabama  (kphoffman@crimson.ua.edu)