Cryptosporidium and Giardia in Water: Reassessment of Occurrence and Significance
Publication: Journal of Environmental Engineering
Volume 143, Issue 3
Abstract
The current approach in the U.S. water industry for monitoring Cryptosporidium and Giardia has weaknesses that have contributed to the difficulty of interpreting resulting data. This often leads to potentially significant and dangerous misinterpretation. The purpose of this paper is to summarize information on which the conflicting conclusions on the occurrence and distribution of Cryptosporidium and Giardia have been based. Effort is made to determine the most plausible and supportable interpretation. The objective is to provide a basis for rethinking the current approach to monitoring and management of Cryptosporidium and Giardia in water. The importance of measuring recovery efficiency and reporting measurements of these organisms in terms of concentration to any quantitative application is emphasized. Data presentation to illustrate critical features of organism concentration levels and variation is reviewed. Analysis of major data sets resulting from the U.S. Environmental Protection Agency Information Collection Rule Supplemental Survey (USEPA ICR SS) and the Long-Term 2 Enhanced Surface Water Treatment Rule (LT2) monitoring and other previously published relevant data sets is presented to illustrate key features of Cryptosporidium and Giardia occurrence in surface water and their universal geographic distribution. Current thinking emphatically requires revision.
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References
Chow, V. T. (1954). “The log-probability law and its engineering applications.” Proc. Am. Soc. Civ. Eng., 80(1–125), 536-1–536-25.
Haas, C. N., and Rose, J. B. (1996). “Distribution of Cryptosporidium oocysts in a water supply.” Water Res., 30(10), 2251–2254.
Hansen, J., and Ongerth, J. E. (1991). “Effects of time and watershed characteristics on the concentration of Cryptosporidium oocysts in river water.” Appl. Environ. Microbiol., 57(10), 2790–2795.
LeChevallier, M. W., Norton, W. D., and Lee, R. G. (1991). “Occurrence of Giardia and Cryptosporidium spp. in surface water supplies.” Appl. Environ. Microbiol., 57(9), 2610–2616.
Messner, M. (2011). “USEPA LT2 round 1 Cryptosporidium occurrence.” ⟨http://water.epa.gov/lawsregs/rulesregs/sdwa/lt2/upload/lt2round1crypto.pdf⟩ (Jun. 10, 2015).
Ongerth, J. E. (1989). “Giardia cyst concentrations in river water.” J. Am. Water Works Assoc., 81(9), 81–86.
Ongerth, J. E. (2013a). “ICR SS protozoan data site-by-site—A picture of Cryptosporidium and Giardia in USA surface water.” Environ. Sci. Technol., 47(18), 10145–10154.
Ongerth, J. E. (2013b). “The LT2 Cryptosporidium data…What do they tell us about Cryptosporidium in surface water in the USA?” Environ. Sci. Technol., 47(9), 4029–4038.
Ongerth, J. E. (2013c). “The concentration of Cryptosporidium and Giardia in water—The role and importance of recovery efficiency.” Water Res., 47(7), 2479–2488.
OriginPro [Computer software]. OriginLab, Northhampton, MA.
USEPA (U.S. Environmental Protection Agency). (1995). “ICR protozoan method for detecting Giardia cysts and Cryptosporidium oocysts in water by a fluorescent antibody procedure.” EPA/14-B-95-003, Washington, DC.
USEPA (U.S. Environmental Protection Agency). (1996). “National primary drinking water regulation: Monitoring for public water supplies; final rule.” Fed. Regist., 61(94), 24353–24388, Washington, DC.
USEPA (U.S. Environmental Protection Agency). (2005a). “Appendix A. Waterborne outbreaks caused by microbial agents in public water systems 1991–2000.” EPA 814-R-06-002, Washington, DC.
USEPA (U.S. Environmental Protection Agency). (2005b). “Occurrence and exposure assessment for the final long term enhanced surface water treatment rule.” EPA 815-R-06-002, Washington, DC.
USEPA (U.S. Environmental Protection Agency). (2006). “Long term 2 enhanced surface water treatment rule.” ⟨https://Federalregister.gov/a/06-4⟩ (May 10, 2016).
Information & Authors
Information
Published In
Journal of Environmental Engineering
Volume 143 • Issue 3 • March 2017
Copyright
© 2016 American Society of Civil Engineers.
History
Received: Apr 12, 2016
Accepted: Jun 1, 2016
Published online: Sep 13, 2016
Discussion open until: Feb 13, 2017
Published in print: Mar 1, 2017
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