Skip common site navigation and headers
United States Environmental Protection Agency
Exposure Research
Begin Hierarchical Links EPA Home > Research & Development > Exposure Research > Publications/Presentations > End Hierarchical Links

 

Evaluation of Spiking Procedures for Recovery of Cryptosporidium in Stream Waters Using USEPA Method 1623

spacer
spacer
Abstract:U.S. Environmental Protection Agency Method 1623 is widely used to monitor source waters and drinking water supplies for Cryptosporidium oocysts. Analyzing matrix spikes is an important component of Method 1623. Matrix spikes are used to determine the effect of the environmental matrix on the method's recovery efficiency for the target organism and require the collection and analysis of two environmental samples. Using a new product, ColorSeed, spiked organisms can be differentiated from unmodified organisms and thus recovery efficiencies can be determined by analyzing only one environmental sample. Twenty-nine stream-water samples and one effluent sample were collected to compare ColorSeed to traditional spiking procedures. Adjusted recoveries of oocysts ranged from 2.8 to 49 percent for viable oocysts (traditional spiking procedure) and 3.1 to 59 percent for ColorSeed. The recoveries between the two spiking procedures were highly correlated (r = 0.802) and were not found to be significantly different. Recoveries using ColorSeed, therefore, were comparable to recoveries using traditional spiking procedures. Collecting and processing these samples afforded the opportunity to address other issues regarding the use of Method 1623 for monitoring environmental waters. In examining the effects of water-qualiy variables on method recovery efficiency of oocysts, significant negative correlations were found between average oocyst recovery and turbidity or suspended sediment; this was especially apparent in samples with turbidities greater than 100 NTU and suspended-sediment concentrations greater than 100 mg/L. Because oocysts were found in a small percentage of samples (16.7 percent), the presence of Cryptosporidium was qualitatively compared to concentrations of microbiological indicators and to concentrations of chemical constituents known to be associated with fecal contamination. Concentrations of E. coli, F-specific coliphage, and total phosphorus were above the median non-detection concentrations in all samples with detections of Cryptosporidium, but were not above the median for Cl. perfringens, somatic coliphage, chloride, and nitrate.
spacer
Citation:Simmons, O. D., D. S. Francy, E. J. Granger, M. W. Ware, M. D. Sobsey, and F. W. Schaefer III. Evaluation of Spiking Procedures for Recovery of Cryptosporidium in Stream Waters Using USEPA Method 1623. Presented at 104th General Meeting of the American Society for Microbiology, New Orleans, LA, May 23-27, 2004.
spacer
spacer
Contact: Mary P. O'Bryant - (919)-541-4871 or obriant.mary@epa.gov
spacer
Division: Microbiological & Chemical Exposure Assessment Division
spacer
Branch: Biohazard Assessment Research Branch
spacer
Product Type: Abstrct/Oral
spacer
Presented: 05/23/2004
spacer
Related Entries:
spacer
Bullet Item Detecting Ccl-Related, Emerging and Regulated Waterborne Human Protozoa for Exposure Assessment
spacer Relationship Reason:   A Project of the Product
spacer
spacer
spacer

 

ORD Home | Search EPA | Search NERL | Search EIMS | Contacts | Help

 
Begin Site Footer

EPA Home | Privacy and Security Notice | Contact Us

Last Updated on Monday, October 22, 2007
URL: http://cfpub.epa.gov