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DETECTION OF CRYPTOSPORIDIUM OOCYSTS IN STREAM WATER SAMPLES USING U.S. ENVIRONMENTAL PROTECTION AGENCY METHOD 1622
Citation:
Simmons, O. D., C. D. Heaney, D. S. Francy, R. Nally, F W. Schaefer, AND M. D. Sobsey. DETECTION OF CRYPTOSPORIDIUM OOCYSTS IN STREAM WATER SAMPLES USING U.S. ENVIRONMENTAL PROTECTION AGENCY METHOD 1622. JOURNAL OF THE AMERICAN WATER WORKS ASSOCIATION 67(3):1123-1127, (2001).
Impact/Purpose:
1) Refine new, practical methods for the detection of CCL-related and emerging waterborne human protozoa.
2) Perform field tests of devices or methods that have been developed under this task.
3) Evaluate these methods or devices in a variety of water matrices and parasite concentrations.
This work in this task supports CCL2 and 3 and is expected to be completed by 9/07.
Description:
To improve surveillance for cryptosporidium oocysts in water the USEPA developed Method 1622 which consists of filtration, concentration, immunomagnetic separation, fluorescent antibody and DAPI counter staining, and microscopic evaluation. Two filters were compared for analysis of 11 stream water samples collected throughout the U.S. 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% and 12% with a membrane disk and a capsule filter, respectively. These results demonstrate that cryptosporidium oocysts can be recovered from stream waters using Method 1622 but recoveries are lower than from reagent-grade water. Concentrations of indicator bacteria also were evaluated in these steam water samples. Because few samples were oocyst-positive, relationships between detections of oocysts and concentrations of indicator organisms could not be determined.