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Relationships and trends of E. Coli, human-associated Bacteroides, and pathogens in the Proctor Creek Watershed
Citation:
Snyder, B., M. Molina, AND O. Georgacopoulos. Relationships and trends of E. Coli, human-associated Bacteroides, and pathogens in the Proctor Creek Watershed. Georgia Water Resources Conference, Athens, GA, April 19 - 20, 2017.
Impact/Purpose:
Urban streams can be negatively impacted by anthropogenic sources Sanitary and storm sewers Failing infrastructure Impervious surfaces
Description:
Urban surface waters can be impacted by anthropogenic sources such as impervious surfaces, sanitary and storm sewers, and failing infrastructure. Fecal indicator bacteria (FIB) and microbial source tracking (MST) markers are common gauges of stream water quality, however, little is known about their relationship with public health. In this study, we measured culturable and molecular concentrations of E. coli, a human-associated Bacteroides marker (HF183MGB), and selected waterborne pathogens and toxins (Salmonella sp. and Shiga-toxin (Stx2)) in surface water throughout a highly urbanized watershed near downtown Atlanta, GA to determine if any relationships exist between these parameters. The Proctor Creek watershed, a tributary to the Chattahoochee River, consistently fails fecal coliform standards and is therefore, listed on the Environmental Protection Agency’s (EPA) 303(d) impaired waters list. Water grab samples were taken at 12 locations throughout the watershed every two weeks for one year. Culturable E. coli concentrations varied greatly throughout the watershed (24 to 101,330 MPN/100 mL). The human associated marker was widespread throughout the watershed and correlated highly with molecular E. coli (R2 = 0.63). Salmonella was present at all mainstem and half of the tributary sites, whereas Stx-2 was widespread throughout the entire watershed but was most frequently found at headwater locations where storm water inlets and outfalls were more prevalent. Based on their high correlation, E. coli could be a useful parameter in predicting human-associated Bacteroides in this watershed. Our results also indicate that major and consistent human sources of fecal contamination are present throughout the watershed suggesting that sanitary sewer leaks could be widespread across the region.
