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Environmental Health - Toxic Substances

Research Projects - Emerging Contaminants

Emerging Microbial Contaminants - National-Scale Research

Surface waters are commonly monitored for the presence of fecal indicator bacteria, but little is known regarding the co-occurrence of common disease-causing bacteria. Toxic Substances Hydrology Program researchers are analyzing surface-water samples collected during a Source-Water Reconnaissance for the presence of pathogenic Escherichia coli and Enterococcus bacteria and are evaluating relations between their occurrence and measures of land use and water quality. Fecal coliform and E. coli bacteria concentrations were determined using standard methods. Pathogenic E. coli (exemplified by E. coli O157:H7) were detected using a DNA-based method that differentiates three virulence genes: eaeA (adhesion protein) and stx1 and stx2 (Shiga Toxins 1 and 2). Positive samples were further analyzed using culture-based methods. Detections of shiga-toxin genes varied with land-use in the watershed. Relations are being examined between these gene detections and chemical water-quality profiles for the same samples (e.g., caffeine, triclosan, antibiotics, industrial chemicals, urban- vs agricultural pesticides, nitrogen and phosphorous, chloride, etc.). These data will be useful for interpreting the significance of indicator bacteria numbers in various environmental settings. In addition, these data may be useful for setting Total Maximum Daily Loads (TMDLs), and for evaluating the effect of various sources of bacterial contamination on surface waters.

Available Publications

Haack, S.K., Duris, J.W., Fogarty, L.R., Kolpin, D.W., Focazio, M.J., Furlong, E.T., and Meyer, M.T., 2009, Comparing wastewater chemicals, indicator bacteria concentrations, and bacterial pathogen genes as fecal pollution indicators: Journal of Environmental Quality, v. 38, no. 1, p. 248-258, doi:10.2134/jeq2008.0173.

More Information

  • Project contact: Sheridan Haack

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