AWWA JAW36162

The authors conducted a blind survey of 16 commercial laboratories in order to evaluate their ability to test for Giardia and Cryptosporidium using the American Society for Testing and Materials (ASTM) method. After filters were spiked with approximately 740 Giardia cysts and Cryptosporidium oocysts or 500 cells of the alga Oocystis, they were sent to the laboratories for analysis. For the laboratories that submitted reports, Giardia cyst recoveries ranged from 0.8 to 22.3 percent, averaging 9.1 percent; Cryptosporidium oocyst recoveries ranged from 1.3 to 5.5 percent, averaging 2.8 percent. Four of the laboratories falsely reported the Oocystis as positive, four laboratories failed to recover the Giardia cysts, and six laboratories failed to recover the Cryptosporidium oocysts. Not all laboratories strictly followed the ASTM method. The majority of laboratories need to make improvements in one or more of the following areas: response to clients, adequacy of sampling equipment and directions for use, analytical methods, and data accuracy. Includes 12 references, tables, figure.

Product Details

Edition:

Vol. 86 - No. 5

Published:

05/01/1994

Number of Pages:

9

File Size:

1 file , 18 MB