AWWA WQTC65881

The current project explored various modifications to United States Environmental Protection Agency Method 1623. Method 1623 is a performance-based method for the analysis of Cryptosporidium and Giardia in water. The various modifications that were tested included: filter type; slide type; methanol fixation; elution buffer; IFA kit; and, sample resuspension method. These variations were assessed in terms of the mean percent recovery and percent relative standard deviation that was achieved. The first modification assessed was stain, followed by methanol fixation, and slide type. After that initial assessment, the best combination was selected and used in the processing of other samples. After a filter was selected, subsequent samples were subjected to changes in transfer method, and elution buffer. All future modifications that increased the percent recovery, without any adverse effects, were used for the analysis of subsequent samples. The desired end result was an optimized method that achieved the best percent recoveries and the least variable recoveries in various water matrices. Includes 18 references, figures.