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Influence of Impervious Surfaces on Pathogen Occurrence and Human-Associated Bacteroides in an Urbanized Stream
Citation:
Snyder, B., M. Molina, AND O. Georgacopoulos. Influence of Impervious Surfaces on Pathogen Occurrence and Human-Associated Bacteroides in an Urbanized Stream. ASM Microbe 2018, Atlanta, GA, June 07 - 11, 2018.
Impact/Purpose:
Overview of study which examined if impervious surface cover could be used as a predictor for pathogen (Salmonella sp.), Shiga-toxin (Stx-2), E. coli (culturable and molecular) or human-associated Bacteroides marker (HF183MGB) occurrence in an urban watershed.
Description:
Urban surface waters can be impacted by anthropogenic sources such as impervious surfaces, sani-tary and storm sewers, and failing infrastructure. Fecal indicator bacteria (FIB) and microbial source tracking (MST) markers are common gauges of stream water qual-ity, 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 water-borne pathogens and toxins (Salmonella sp. and Shiga-toxin (Stx2)) in surface water throughout a highly urban-ized 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 Agen-cy’s (EPA) 303(d) impaired waters list. Water grab sam-ples were taken at 12 locations throughout the watershed every two weeks for one year. Culturable E. coli concen-trations 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 wa-tershed but was most frequently found at headwater loca-tions 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 contam-ination are present throughout the watershed suggesting that sanitary sewer leaks could be widespread across the region.
