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TRANSPORT OF CHEMICAL AND MICROBIAL CONTAMINANTS FROM KNOWN WASTEWATER DISCHARGES
Citation:
Glassmeyer, S, I. Ferrer, E. T. Furlong, J. D. Cahill, S. D. Zaugg, S. L. Werner, D. W. Kolpin, AND D D. Kryak. TRANSPORT OF CHEMICAL AND MICROBIAL CONTAMINANTS FROM KNOWN WASTEWATER DISCHARGES. Presented at National Groundwater Association 3rd International Conference on Pharmaceuticals and Endocrine Disrupting Chemicals in Water, Minneapolis, MN, March 19-21, 2003.
Impact/Purpose:
The objectives of this task are to evaluate a large suite of chemical compounds for their correlation with the concentration of indicator microbes, and determine their ability to monitor water quality in source and finished waters as a surrogate for traditional methods of human fecal contamination.
Description:
The quality of drinking and recreational water is currently ascertained using indicator bacteria, such as Escherichia coli and fecal enterococci. However, the tests to analyze for these bacteria require a considerable length of time to complete, and do not discriminate between human and animal fecal material sources. One solution to these problems is to use chemicals that are commonly found in human wastewater as supplementary tracer compounds. The chemicals have the advantage of requiring shorter analysis times, and they can be chosen to be human specific markers.
For this project, we focused on a variety of compounds to determine their efficacy as chemical indicators of human fecal contamination. This list included compounds that are produced and excreted by humans (coprostanol, urobilin), that are consumed and pass easily through humans (pharmaceuticals and caffeine), and that are associated with humans and deposited into the combined graywater/ blackwater household septic waste stream (surfactants). Stream samples were collected upstream, at the point of discharge, and at two points downstream from wastewater treatment facilities at ten locations. This longitudinal sampling scheme was developed to determine the persistence of the compounds in streams. Compounds that are quickly removed or degraded may not be persistent enough to serve as tracers; those that are too recalcitrant would similarly not be suitable as they would be present after the pathogens have been eliminated. To estimate the desired duration, the water samples were analyzed for E. coli and fecal enterococci in addition to the suite of chemicals. For the chemicals, the water samples were extracted using either solid phase extraction (for the pharmaceuticals) or liquid-liquid extraction (for the other wastewater contaminants) and were analyzed using either high-performance liquid chromatography/mass spectrometry (HPLC/MS; pharmaceuticals) or gas chromatography/mass spectrometry (GC/MS; other wastewater contaminants; Kolpin et al., 2002). To analyze for the microbial contaminants, three aliquots of water (100, 10, and 1 mL) were filtered through cellulose disks and placed on modified mTEC (E. coli, ) or mEI (enterococci) media and incubated (USEPA, 2000).