STORM AND SEASONAL DISTRIBUTIONS OF FECAL COLIFORMS AND CRYPTOSPORIDIUM IN A SPRING

Authors: Boyer, Douglas; Kuczynska, Ewa

Submitted to: Journal of the American Water Resources Association
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/30/2003
Publication Date: 12/31/2003
Citation: BOYER, D.G., KUCZYNSKA, E. STORM AND SEASONAL DISTRIBUTIONS OF FECAL COLIFORMS AND CRYPTOSPORIDIUM IN A SPRING. JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION. DECEMBER 2003. PP 1449-1456.

Interpretive Summary: 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 concern about pathogen transport through karst aquifers. We studied changes in fecal coliform bacteria concentrations and Cryptosporidium parvum oocyst concentrations during storms at an agriculturally impacted karst spring in southeastern West Virginia. Cryptosporidium parvum oocyst concentrations were not correlated with fecal coliform concentrations or with flow. Fecal coliform concentrations were correlated with flow during storms. Cryptosporidium oocysts appeared to be transported to the epikarstic zone (soil/bedrock interface) where they accumulated under ideal environmental conditions until saturated conditions caused epikarstic storage to be flushed into the aquifer. Fecal coliform densities were greatest at storm peaks, when sediment loads were also greatest, and did not exhibit much seasonality indicating that direct influence of surface flow into the aquifer was the primary transport mechanism. Multiple transport mechanisms may necessitate various agricultural land management and livestock health maintenance practices to control movement of pathogens to karst groundwater.

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 concern about pathogen transport through karst aquifers. The purpose of this study was to compare the temporal variability, in stormflow, of fecal coliform bacteria densities and Cryptosporidium parvum oocyst densities in agriculturally impacted karst groundwater. 1316 storm samples were collected during 50 separate storms from December 1999 through August 2001. Cryptosporidium oocyst densities ranged from 0 L-1 to 1050 L-1 and flow-weighted mean storm densities ranged from 4 oocysts L-1 to 154 oocysts L-1. Fifty-three percent of the samples were positive for C. parvum. Fecal coliform densities ranged from <1 CFU 100 mL-1 to 40,000 CFU 100 mL-1 and flow-weighted mean storm densities ranged from 493 CFU 100 mL-1 to 12,027 CFU 100 mL-1. Ninety-one percent of the samples were positive for fecal coliforms. Fecal coliform densities correlated well with flow during storms, but Cryptosporidium oocyst densities exhibited a great deal of sample-to-sample variability and were not correlated with flow. Fecal coliform densities did not correlate positively with Cryptosporidium oocyst densities. Cryptosporidium oocysts appeared to be transported to the epikarstic zone where they accumulated under optimum environmental conditions until saturated conditions caused epikarstic storage to be flushed into the aquifer. Fecal coliform densities were greatest at storm peaks, when sediment loads were also greatest, and did not exhibit much seasonality indicating that direct influence of surface flow into the aquifer was the primary transport mechanism. Multiple transport mechanisms may necessitate various agricultural land management and livestock health maintenance practices to control movement of pathogens to karst groundwater.