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Title: TEMPORAL VARIABILITY OF FECAL COLIFORM AND CRYPTOSPORIDIUM DENSITIES

Author
item Boyer, Douglas
item Kuczynska, Ewa

Submitted to: American Water Resources Association Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 3/30/2002
Publication Date: 6/30/2002
Citation: Boyer, D.G., Kuczynska, E. 2002. Temporal variability of fecal coliform and cryptosporidium densities. Summer Specialty Conference on Ground Water Surface Water Interactions, Keystone, CO, American Water Resources Association, Middleburg, VA, p. 594.

Interpretive Summary:

Technical Abstract: The transmission of disease in groundwater is a topic of great concern to government agencies, groundwater specialists, and the general public. The intricate mix of surface water and groundwater in karst terrain leads to concerns about pathogen transport through karst aquifers. The purpose of this study was to compare the temporal variability, in storm flow, of fecal coliform bacteria densities and Cryptosporidium parvum oocyst densities in karst groundwater impacted by grazing livestock. Storm samples (831) were collected during 35 separate storms from December 1999 through January 2001 at a carbonate spring in southeastern West Virginia. A data logger instrumented with a pressure transducer to measure water stage at the spring triggered an automatic water sampler to collect one-liter samples every 45 minutes once storm flow commenced. Fecal coliform densities correlated well with flow during storms, but Cryptosporidium parvum oocyst densities exhibited a great deal of sample-to-sample variability and were not correlated with flow. Cryptosporidium parvum oocyst densities tended to peak prior to the storm peak flow, but fecal coliform densities often peaked after the storm peak flow. The timing differences indicate that the sources of the organisms differ. Cryptosporidium parvum oocysts appear to be entering ground water from a subsurface storage pool - probably the epikarstic zone. Surface runoff appears to be the source delivery mechanism for fecal coliform bacteria. Seasonal differences in flow-weighted mean storm densities were observed for both Cryptosporidium parvum oocysts and fecal coliform bacteria. Flow-weighted mean storm Cryptosporidium parvum oocyst densities were greatest in late autumn and winter whereas flow-weighted mean fecal coliform bacteria densities were greatest in summer. Differential timings of delivery of different microorganisms to the groundwater are problematic. Multiple agricultural land management strategies may be needed to control transport of various pathogens to karst groundwater.