Evaluation of USEPA method 1622 for detection of Cryptosporidium oocysts in stream waters

Journal - American Water Works Association
By: , and 

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Abstract

To improve surveillance for Cryptosporidium oocysts in water, the US Environmental Protection Agency developed method 1622, which consists of filtration, concentration, immunomagnetic separation, fluorescent antibody and 4, 6-diamidino-2-phenylindole (DAPI) counter-staining, and microscopic evaluation. Two filters were compared for analysis of 11 stream water samples collected throughout the United States. Replicate 10-L stream water samples (unspiked and spiked with 100–250 oocysts) were tested to evaluate matrix effects. Oocyst recoveries from the stream water samples averaged 22% (standard deviation [SD] = ±17%) with a membrane disk and 12% (SD = ±6%) with a capsule filter. Oocyst recoveries from reagent water precision and recovery samples averaged 39% (SD = ±13%) with a membrane disk and 47% (SD = ±19%) with a capsule filter. These results demonstrate that Cryptosporidium oocysts can be recovered from stream waters using method 1622, but recoveries are lower than those from reagent-grade water. This research also evaluated concentrations of indicator bacteria in the stream water samples. Because few samples were oocyst-positive, relationships between detections of oocysts and concentrations of indicator organisms could not be determined.

Publication type Article
Publication Subtype Journal Article
Title Evaluation of USEPA method 1622 for detection of Cryptosporidium oocysts in stream waters
Series title Journal - American Water Works Association
DOI 10.1002/j.1551-8833.2001.tb09101.x
Volume 93
Issue 1
Year Published 2001
Language English
Publisher American Water Works Association
Publisher location Denver, CO, United States
Description 10 p.
First page 78
Last page 87
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